The evaluation model of the enterprise energy efficiency based on DPSR.

PubMed

Wei, Jin-Yu; Zhao, Xiao-Yu; Sun, Xue-Shan

2017-05-08

The reasonable evaluation of the enterprise energy efficiency is an important work in order to reduce the energy consumption. In this paper, an effective energy efficiency evaluation index system is proposed based on DPSR (Driving forces-Pressure-State-Response) with the consideration of the actual situation of enterprises. This index system which covers multi-dimensional indexes of the enterprise energy efficiency can reveal the complete causal chain which includes the "driver forces" and "pressure" of the enterprise energy efficiency "state" caused by the internal and external environment, and the ultimate enterprise energy-saving "response" measures. Furthermore, the ANP (Analytic Network Process) and cloud model are used to calculate the weight of each index and evaluate the energy efficiency level. The analysis of BL Company verifies the feasibility of this index system and also provides an effective way to improve the energy efficiency at last.

Production efficiencies of U.S. electric generation plants: Effects of data aggregation and greenhouse gas and renewable energy policy

NASA Astrophysics Data System (ADS)

Lynes, Melissa Kate

Over the last few decades there has been a shift in electricity production in the U.S. Renewable energy sources are becoming more widely used. In addition, electric generation plants that use coal inputs are more heavily regulated than a couple decades ago. This shift in electricity production was brought on by changes in federal policy -- a desire for electricity produced in the U.S. which led to policies being adopted that encourage the use of renewable energy. The change in production practices due to policies may have led to changes in the productivity of electric generation plants. Multiple studies have examined the most efficient electric generation plants using the data envelopment analysis (DEA) approach. This study builds on past research to answer three questions: 1) Does the level of aggregation of fuel input variables affect the plant efficiency scores and how does the efficiency of renewable energy input compare to nonrenewable energy inputs; 2) Are policies geared toward directly or indirectly reducing greenhouse gas emissions affecting the production efficiencies of greenhouse gas emitting electric generation plants; and 3) Do renewable energy policies and the use of intermittent energy sources (i.e. wind and solar) affect the productivity growth of electric generation plants. All three analysis, presented in three essays, use U.S. plant level data obtained from the Energy Information Administration to answer these questions. The first two essays use DEA to determine the pure technical, overall technical, and scale efficiencies of electric generation plants. The third essay uses DEA within the Malmquist index to assess the change in productivity over time. Results indicate that the level of aggregation does matter particularly for scale efficiency. This implies that valuable information is likely lost when fuel inputs are aggregated together. Policies directly focused on reducing greenhouse gas emissions may improve the production efficiencies of greenhouse gas emitting electric generation plants. However, renewable energy policies do not have an effect on productivity growth. Renewable energy inputs are found to be as efficient if not more efficient than traditional energy sources.

Energy sustainability: consumption, efficiency, and ...

EPA Pesticide Factsheets

One of the critical challenges in achieving sustainability is finding a way to meet the energy consumption needs of a growing population in the face of increasing economic prosperity and finite resources. According to ecological footprint computations, the global resource consumption began exceeding planetary supply in 1977 and by 2030, global energy demand, population, and gross domestic product are projected to greatly increase over 1977 levels. With the aim of finding sustainable energy solutions, we present a simple yet rigorous procedure for assessing and counterbalancing the relationship between energy demand, environmental impact, population, GDP, and energy efficiency. Our analyses indicated that infeasible increases in energy efficiency (over 100 %) would be required by 2030 to return to 1977 environmental impact levels and annual reductions (2 and 3 %) in energy demand resulted in physical, yet impractical requirements; hence, a combination of policy and technology approaches is needed to tackle this critical challenge. This work emphasizes the difficulty in moving toward energy sustainability and helps to frame possible solutions useful for policy and management. Based on projected energy consumption, environmental impact, human population, gross domestic product (GDP), and energy efficiency, for this study, we explore the increase in energy-use efficiency and the decrease in energy use intensity required to achieve sustainable environmental impact le

Statistical properties of proportional residual energy intake as a new measure of energetic efficiency.

PubMed

Zamani, Pouya

2017-08-01

Traditional ratio measures of efficiency, including feed conversion ratio (FCR), gross milk efficiency (GME), gross energy efficiency (GEE) and net energy efficiency (NEE) may have some statistical problems including high correlations with milk yield. Residual energy intake (REI) or residual feed intake (RFI) is another criterion, proposed to overcome the problems attributed to the traditional ratio criteria, but it does not account for production or intake levels. For example, the same REI value could be considerable for low producing and negligible for high producing cows. The aim of this study was to propose a new measure of efficiency to overcome the problems attributed to the previous criteria. A total of 1478 monthly records of 268 lactating Holstein cows were used for this study. In addition to FCR, GME, GEE, NEE and REI, a new criterion called proportional residual energy intake (PREI) was calculated as REI to net energy intake ratio and defined as proportion of net energy intake lost as REI. The PREI had an average of -0·02 and range of -0·36 to 0·27, meaning that the least efficient cow lost 0·27 of her net energy intake as REI, while the most efficient animal saved 0·36 of her net energy intake as less REI. Traditional ratio criteria (FCR, GME, GEE and NEE) had high correlations with milk and fat corrected milk yields (absolute values from 0·469 to 0·816), while the REI and PREI had low correlations (0·000 to 0·069) with milk production. The results showed that the traditional ratio criteria (FCR, GME, GEE and NEE) are highly influenced by production traits, while the REI and PREI are independent of production level. Moreover, the PREI adjusts the REI magnitude for intake level. It seems that the PREI could be considered as a worthwhile measure of efficiency for future studies.

10 CFR Appendix B to Subpart F of... - Sampling Plan For Enforcement Testing

Code of Federal Regulations, 2010 CFR

2010-01-01

... sample as follows: ER18MR98.010 where (x 1) is the measured energy efficiency, energy or water (in the...-tailed probability level and a sample size of n 1. Step 6(a). For an Energy Efficiency Standard, compare... an Energy Efficiency Standard, determine the second sample size (n 2) as follows: ER18MR98.015 where...

Monitoring trends in civil engineering and their effect on indoor radon.

PubMed

Ringer, W

2014-07-01

In this paper, the importance of monitoring new building concepts is discussed. The effect of energy-efficient construction technologies on indoor radon is presented in more detail. Comparing the radon levels of about 100 low-energy and passive houses in Austria with radon levels in conventional new houses show that, in energy-efficient new houses, the radon level is about one-third lower than in conventional new houses. Nevertheless, certain features or bad practice may cause high radon levels in energy-efficient new houses. Recommendations to avoid adverse effects were set up. Furthermore, the paper deals with the effect of thermal retrofitting on indoor radon. Results from a Swiss study where 163 dwellings were measured before and after thermal retrofit yield an increase of the radon level of 26% in average. Among the various retrofit measures, replacing windows has the greatest impact on the indoor radon level. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Energy efficiency, human behavior, and economic growth: Challenges to cutting energy demand to sustainable levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santarius, Tilman, E-mail: tilman@santarius.de

Increasing energy efficiency in households, transportation, industries, and services is an important strategy to reduce energy service demand to levels that allow the steep reduction of greenhouse gases, and a full fledged switch of energy systems to a renewable basis. Yet, technological efficiency improvements may generate so-called rebound effects, which may ‘eat up’ parts of the technical savings potential. This article provides a comprehensive review of existing research on these effects, raises critiques, and points out open questions. It introduces micro-economic rebound effect and suggests extending consumer-side analysis to incorporate potential ‘psychological rebound effects.’ It then discusses meso-economic rebound effects,more » i.e. producer-side and market-level rebounds, which so far have achieved little attention in the literature. Finally, the article critically reviews evidence for macro-economic rebound effects as energy efficiency-induced economic growth impacts. For all three categories, the article summarizes assessments of their potential quantitative scope, while pointing out remaining methodological weaknesses and open questions. As a rough “rule of thumb”, in the long term and on gross average, only half the technical savings potential of across-the-board efficiency improvements may actually be achieved in the real world. Policies that aim at cutting energy service demand to sustainable levels are well advised to take due note of detrimental behavioral and economic growth impacts, and should foster policies and measures that can contain them.« less

Milk production and energy efficiency of Holstein and Jersey-Holstein crossbred dairy cows offered diets containing grass silage.

PubMed

Xue, B; Yan, T; Ferris, C F; Mayne, C S

2011-03-01

Eight Holstein and 8 Jersey-Holstein crossbred dairy cows (all primiparous) were used in a repeated 2 (genotype) × 2 (concentrate level) factorial design study involving a total of 4 periods (each of 6-wk duration), designed to examine the effect of cross-breeding on the efficiency of milk production and energy use. The 4 periods began at 5, 11, 27, and 33 wk of lactation, respectively. Animals were offered a completely mixed diet containing grass silage and concentrates, with the level of concentrate in the diet either 30 or 70% of dry matter (DM). During the final 10 d of each period, ration digestibility and energy use was measured, the latter in indirect open-circuit respiration calorimeters. No significant interaction existed between cow genotype and dietary concentrate level for feed intake, milk production, or any of the energy use parameters measured. Across the 2 genotypes, total DM intake, milk yield, and milk protein and lactose concentrations increased with increasing dietary concentrate level. Thus, cows offered the high-concentrate diet had a higher gross energy (GE) intake, and a higher energy output in feces, urine, milk as heat, and a higher metabolizable energy (ME) intake as a proportion of GE intake and as a proportion of digestible energy intake. Across the 2 levels of concentrates, the Jersey-Holstein cows had a significantly higher total DM intake and body condition score, and produced milk with higher fat, protein, and energy concentrations, compared with those of the Holstein cows. In addition, the Jersey-Holstein cows had a significantly higher GE intake and energy output in urine, methane, and milk. However, crossbreeding had no significant effect on energy digestibility or metabolizability, energy partitioning between milk and body tissue, or the efficiency of ME use for lactation. Relating ME intake to milk energy output and heat production indicated that crossbreeding did not influence ME requirement for maintenance or energy efficiencies. The energy metabolism data were also used to compare energy efficiencies between "early" (data pooled for the first 2 periods) and "late" (data pooled for the second 2 periods) stages of lactation. Stage of lactation had no effect on energy digestibility or metabolizability, whereas increasing stage of lactation increased the rate of energy partitioning into body tissue and reduced the rate of energy partitioning into milk, irrespective of cow genotype. In conclusion, crossbreeding of Holstein dams with Jersey sires had no adverse effects on the overall production efficiency of Holstein dairy cows in terms of milk production, efficiency of ME use for lactation, and energy partitioning between milk and body tissue. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Energy Efficiency for Architectural Drafting Instructors.

ERIC Educational Resources Information Center

Scharmann, Larry, Ed.

Intended primarily but not solely for use at the postsecondary level, this curriculum guide contains five units on energy efficiency that were designed to be incorporated into an existing program in architectural drafting. The following topics are examined: energy conservation awareness (residential energy use and audit procedures); residential…

Buy Energy-Efficient Products: A Guide for Federal Purchasers and Specifiers

DOE Office of Scientific and Technical Information (OSTI.GOV)

In a single year, energy-efficient product purchases could save the federal government almost a half billion dollars worth of energy. By purchasing products that exceed the minimum required efficiency levels, buyers can save the government even more energy and money. Federal employees and contractors must take an active role in ensuring that the government receives products that meet efficiency requirements. This document provides an overview of product purchasing requirements and shows you how to write compliant contracts, find funding, and confirm product compliance.

Gaining Campaign Support through Peer Networking: An Impact Analysis of Energy Efficiency Projects in Malaysia

ERIC Educational Resources Information Center

Mustafa, Hasrina

2010-01-01

This article presents a comprehensive evaluation of the impact of two community projects on energy efficiency held in Malaysia in January 2008. Specifically, the study was undertaken to compare levels of attitudes and practices of energy efficiency between baseline and post-campaign survey; compare electricity consumptions before, one month after,…

Modeling Energy Efficiency As A Green Logistics Component In Vehicle Assembly Line

NASA Astrophysics Data System (ADS)

Oumer, Abduaziz; Mekbib Atnaw, Samson; Kie Cheng, Jack; Singh, Lakveer

2016-11-01

This paper uses System Dynamics (SD) simulation to investigate the concept green logistics in terms of energy efficiency in automotive industry. The car manufacturing industry is considered to be one of the highest energy consuming industries. An efficient decision making model is proposed that capture the impacts of strategic decisions on energy consumption and environmental sustainability. The sources of energy considered in this research are electricity and fuel; which are the two main types of energy sources used in a typical vehicle assembly plant. The model depicts the performance measurement for process- specific energy measures of painting, welding, and assembling processes. SD is the chosen simulation method and the main green logistics issues considered are Carbon Dioxide (CO2) emission and energy utilization. The model will assist decision makers acquire an in-depth understanding of relationship between high level planning and low level operation activities on production, environmental impacts and costs associated. The results of the SD model signify the existence of positive trade-offs between green practices of energy efficiency and the reduction of CO2 emission.

Safeguarding our energy future

NASA Astrophysics Data System (ADS)

1993-02-01

Throughout the past several years, states have been receiving settlement monies distributed from escrow accounts maintained by the Department of Energy and various courts. These monies are paid by oil companies for alleged violations of the petroleum pricing regulations of the 1970's. These funds, commonly referred to as Petroleum Violation Escrow (PVE) or Oil Overcharge funds, have been an important tool in supporting energy efficiency programs and technologies at the state level. The aim of this publication is to highlight some of the many interesting, replicable projects funded with PVE monies and to serve as a resource for successful, energy efficiency programs in planning, technology application, and education. By capturing a number of these innovative state-level programs, this document will expand the information network on renewable energy and energy efficiency and serve as a point of departure for others pursuing similar goals. Projects referenced throughout this publication reflect some of the program areas in which the Department of Energy takes an active interest and fall into the following categories: (1) alternative fuels; (2) industrial efficiency and waste minimization; (3) electric power production from renewable resources; (4) building efficiency; (5) integrated resource planning; and (6) energy education.

Energy Efficient Cluster Based Scheduling Scheme for Wireless Sensor Networks

PubMed Central

Srie Vidhya Janani, E.; Ganesh Kumar, P.

2015-01-01

The energy utilization of sensor nodes in large scale wireless sensor network points out the crucial need for scalable and energy efficient clustering protocols. Since sensor nodes usually operate on batteries, the maximum utility of network is greatly dependent on ideal usage of energy leftover in these sensor nodes. In this paper, we propose an Energy Efficient Cluster Based Scheduling Scheme for wireless sensor networks that balances the sensor network lifetime and energy efficiency. In the first phase of our proposed scheme, cluster topology is discovered and cluster head is chosen based on remaining energy level. The cluster head monitors the network energy threshold value to identify the energy drain rate of all its cluster members. In the second phase, scheduling algorithm is presented to allocate time slots to cluster member data packets. Here congestion occurrence is totally avoided. In the third phase, energy consumption model is proposed to maintain maximum residual energy level across the network. Moreover, we also propose a new packet format which is given to all cluster member nodes. The simulation results prove that the proposed scheme greatly contributes to maximum network lifetime, high energy, reduced overhead, and maximum delivery ratio. PMID:26495417

SEE Action Guide for States: Energy Efficiency as a Least-Cost Strategy to Reduce Greenhouse Gases and Air Pollution and Meet Energy Needs in the Power Sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Lisa; Leventis, Greg; Schiller, Steven R.

This guide is designed to provide information to state decision makers and staff on options to advance energy efficiency through strategies designed or implemented at the state and local levels of government and in the private sector.1 The information in this guide is intended to be useful to a wide variety of partners and stakeholders involved in energy-related discussions and decision-making at state and local levels. These energy efficiency options, or “pathways” as they are identified in this guide, can assist states in using energy efficiency to meet air pollution reduction and other policy objectives such as energy affordability andmore » reliability. A pathway is a set of interdependent actions that results in measurable energy savings streams and associated avoided air emissions and other benefits over a period of time. These activities can include state, local, or private sector regulations, policies, programs and other activities. For each of five broad pathways that offer sizable cost-effective energy savings, the guide addresses likely questions policy makers and regulators face when screening for the best opportunities to advance energy efficiency in their state.« less

Increasing energy efficiency level of building production based on applying modern mechanization facilities

NASA Astrophysics Data System (ADS)

Prokhorov, Sergey

2017-10-01

Building industry in a present day going through the hard times. Machine and mechanism exploitation cost, on a field of construction and installation works, takes a substantial part in total building construction expenses. There is a necessity to elaborate high efficient method, which allows not only to increase production, but also to reduce direct costs during machine fleet exploitation, and to increase its energy efficiency. In order to achieve the goal we plan to use modern methods of work production, hi-tech and energy saving machine tools and technologies, and use of optimal mechanization sets. As the optimization criteria there are exploitation prime cost and set efficiency. During actual task-solving process we made a conclusion, which shows that mechanization works, energy audit with production juxtaposition, prime prices and costs for energy resources allow to make complex machine fleet supply, improve ecological level and increase construction and installation work quality.

The Global Experience of Deployment of Energy-Efficient Technologies in High-Rise Construction

NASA Astrophysics Data System (ADS)

Potienko, Natalia D.; Kuznetsova, Anna A.; Solyakova, Darya N.; Klyueva, Yulia E.

2018-03-01

The objective of this research is to examine issues related to the increasing importance of energy-efficient technologies in high-rise construction. The aim of the paper is to investigate modern approaches to building design that involve implementation of various energy-saving technologies in diverse climates and at different structural levels, including the levels of urban development, functionality, planning, construction and engineering. The research methodology is based on the comprehensive analysis of the advanced global expertise in the design and construction of energy-efficient high-rise buildings, with the examination of their positive and negative features. The research also defines the basic principles of energy-efficient architecture. Besides, it draws parallels between the climate characteristics of countries that lead in the field of energy-efficient high-rise construction, on the one hand, and the climate in Russia, on the other, which makes it possible to use the vast experience of many countries, wholly or partially. The paper also gives an analytical review of the results arrived at by implementing energy efficiency principles into high-rise architecture. The study findings determine the impact of energy-efficient technologies on high-rise architecture and planning solutions. In conclusion, the research states that, apart from aesthetic and compositional interpretation of architectural forms, an architect nowadays has to address the task of finding a synthesis between technological and architectural solutions, which requires knowledge of advanced technologies. The study findings reveal that the implementation of modern energy-efficient technologies into high-rise construction is of immediate interest and is sure to bring long-term benefits.

Assessing National Employment Impacts of Investment in Residential and Commercial Sector Energy Efficiency: Review and Example Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, David M.; Belzer, David B.; Livingston, Olga V.

Pacific Northwest National Laboratory (PNNL) modeled the employment impacts of a major national initiative to accelerate energy efficiency trends at one of two levels: • 15 percent savings by 2030. In this scenario, efficiency activities save about 15 percent of the Annual Energy Outlook (AEO) Reference Case electricity consumption by 2030. It is assumed that additional energy savings in both the residential and commercial sectors begin in 2015 at zero, and then increase in an S-shaped market penetration curve, with the level of savings equal to about 7.0 percent of the AEO 2014 U.S. national residential and commercial electricity consumptionmore » saved by 2020, 14.8 percent by 2025, and 15 percent by 2030. • 10 percent savings by 2030. In this scenario, additional savings begin at zero in 2015, increase to 3.8 percent in 2020, 9.8 percent by 2025, and 10 percent of the AEO reference case value by 2030. The analysis of the 15 percent case indicates that by 2030 more than 300,000 new jobs would likely result from such policies, including an annual average of more than 60,000 jobs directly supporting the installation and maintenance of energy efficiency measures and practices. These are new jobs resulting initially from the investment associated with the construction of more energy-efficient new buildings or the retrofit of existing buildings and would be sustained for as long as the investment continues. Based on what is known about the current level of building-sector energy efficiency jobs, this would represent an increase of more than 10 percent from the current estimated level of over 450,000 such jobs. The more significant and longer-lasting effect comes from the redirection of energy bill savings toward the purchase of other goods and services in the general economy, with its attendant influence on increasing the total number of jobs. This example analysis utilized PNNL’s ImSET model, a modeling framework that PNNL has used over the past two decades to assess the economic impacts of the U.S. Department of Energy’s (DOE’s) energy efficiency programs in the buildings sector.« less

Priority directions of the improvement of energy management at the enterprise

NASA Astrophysics Data System (ADS)

Dyakova, Galina; Izmaylova, Svetlana; Mottaeva, Angela; Karanina, Elena

2017-10-01

The relevance of article is caused by the fact that at the industrial enterprises pay little attention to the matters of energy saving or to the management of energy efficiency. The authors of the article defined that the potential of the increase in energy efficiency as well as the improvement of quality of strategic management at the enterprise, is connected with investment into the human capital. For the improvement of system of energy management, the key indicators of energy efficiency at the individual level are defined, the algorithm of the development of key indicators by means of which the energy efficiency of the human capital will be measured is developed, actions for support to the developed transitional strategy of power management are offered, positive results of formation of the human capital directed to increase in energy efficiency are designated.

Wind energy development in the United States: Can state-level policies promote efficient development of wind energy capacity?

NASA Astrophysics Data System (ADS)

Goldstein, Blair S.

In the absence of strong U.S. federal renewable energy policies, state governments have taken the lead in passing legislation to promote wind energy. Studies have shown that many of these policies, including Renewable Portfolio Standards (RPS), have aided in the development of wind energy capacity nationwide. This paper seeks to analyze whether these state-level policies have led to an efficient development of U.S. wind energy. For the purposes of this paper, wind energy development is considered efficient if competitive markets enable wind capacity to be built in the most cost effective manner, allowing states to trade wind energy between high wind potential states and low wind potential states. This concept is operationalized by analyzing how state policies that incentivize the in-state development of wind energy impact where wind capacity is developed. A multivariate regression model examining wind capacity in the 48 contiguous United States that had some wind capacity between 1999 and 2008 found these in-state policies are associated with increased wind capacity, controlling for states' wind potential. The results suggest that state-level policies are distorting where wind is developed. These findings support the enactment of a more comprehensive federal energy policy, such as a national RPS, a cap-and-trade program, or a targeted federal transmission policy. These federal policies could spur national markets that would result in the more efficient development of U.S. wind energy.

In vitro fragmentation efficiency of holmium: yttrium-aluminum-garnet (YAG) laser lithotripsy--a comprehensive study encompassing different frequencies, pulse energies, total power levels and laser fibre diameters.

PubMed

Kronenberg, Peter; Traxer, Olivier

2014-08-01

To assess the fragmentation (ablation) efficiency of laser lithotripsy along a wide range of pulse energies, frequencies, power settings and different laser fibres, in particular to compare high- with low-frequency lithotripsy using a dynamic and innovative testing procedure free from any human interaction bias. An automated laser fragmentation testing system was developed. The unmoving laser fibres fired at the surface of an artificial stone while the stone was moved past at a constant velocity, thus creating a fissure. The lithotripter settings were 0.2-1.2 J pulse energies, 5-40 Hz frequencies, 4-20 W power levels, and 200 and 550 μm core laser fibres. Fissure width, depth, and volume were analysed and comparisons between laser settings, fibres and ablation rates were made. Low frequency-high pulse energy (LoFr-HiPE) settings were (up to six times) more ablative than high frequency-low pulse energy (HiFr-LoPE) at the same power levels (P < 0.001), as they produced deeper (P < 0.01) and wider (P < 0.001) fissures. There were linear correlations between pulse energy and fragmentation volume, fissure width, and fissure depth (all P < 0.001). Total power did not correlate with fragmentation measurements. Laser fibre diameter did not affect fragmentation volume (P = 0.81), except at very low pulse energies (0.2 J), where the large fibre was less efficient (P = 0.015). At the same total power level, LoFr-HiPE lithotripsy was most efficient. Pulse energy was the key variable that drove fragmentation efficiency. Attention must be paid to prevent the formation of time-consuming bulky debris and adapt the lithotripter settings to one's needs. As fibre diameter did not affect fragmentation efficiency, small fibres are preferable due to better scope irrigation and manoeuvrability. © 2013 The Authors. BJU International © 2013 BJU International.

Energy Efficiency for Building Construction Technology.

ERIC Educational Resources Information Center

Scharmann, Larry, Ed.

Intended primarily but not solely for use at the postsecondary level, this curriculum guide contains five units of materials on energy efficiency that were designed to be incorporated into an existing program in building construction. The following topics are examined: conservation measures (residential energy use and methods for reducing…

Energy Efficiency for Electrical Technology.

ERIC Educational Resources Information Center

Scharmann, Larry, Ed.

Intended primarily but not solely for use at the postsecondary level, this curriculum guide contains five units on energy efficiency that were designed to be incorporated into an existing program in electrical technology. The following topics are examined: where to look for energy waste; conservation methods for electrical consumers, for…

Is Efficiency Enough? Towards a New Framework for Carbon Savingsin the California Residential Sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moezzi, Mithra; Diamond, Rick

2005-10-01

The overall implementation of energy efficiency in the United States is not adequately aligned with the environmental benefits claimed for efficiency, because it does not consider absolute levels of energy use, pollutant emissions, or consumption. In some ways, promoting energy efficiency may even encourage consumption. A more effective basis for environmental policy could be achieved by recognizing the degree and nature of the synchronization between environmental objectives and efficiency. This research seeks to motivate and initiate exploration of alternative ways of defining efficiency or otherwise moderating energy use toward reaching environmental objectives, as applicable to residential electricity use in California.more » The report offers three main recommendations: (1) produce definitions of efficiency that better integrate absolute consumption, (2) attend to the deeper social messages of energy efficiency communications, and (3) develop a more critical perspective on benefits and limitations of energy efficiency for delivering environmental benefits. In keeping with the exploratory nature of this project, the report also identifies ten questions for further investigation.« less

The Next Breakthrough for Organic Photovoltaics?

PubMed

Jackson, Nicholas E; Savoie, Brett M; Marks, Tobin J; Chen, Lin X; Ratner, Mark A

2015-01-02

While the intense focus on energy level tuning in organic photovoltaic materials has afforded large gains in device performance, we argue here that strategies based on microstructural/morphological control are at least as promising in any rational design strategy. In this work, a meta-analysis of ∼150 bulk heterojunction devices fabricated with different materials combinations is performed and reveals strong correlations between power conversion efficiency and morphology-dominated properties (short-circuit current, fill factor) and surprisingly weak correlations between efficiency and energy level positioning (open-circuit voltage, enthalpic offset at the interface, optical gap). While energy level positioning should in principle provide the theoretical maximum efficiency, the optimization landscape that must be navigated to reach this maximum is unforgiving. Thus, research aimed at developing understanding-based strategies for more efficient optimization of an active layer microstructure and morphology are likely to be at least as fruitful.

[Efficiency of industrial energy conservation and carbon emission reduction in Liaoning Pro-vince based on data envelopment analysis (DEA)method.

PubMed

Wang, Li; Xi, Feng Ming; Li, Jin Xin; Liu, Li Li

2016-09-01

Taking 39 industries as independent decision-making units in Liaoning Province from 2003 to 2012 and considering the benefits of energy, economy and environment, we combined direction distance function and radial DEA method to estimate and decompose the energy conservation and carbon emissions reduction efficiency of the industries. Carbon emission of each industry was calculated and defined as an undesirable output into the model of energy saving and carbon emission reduction efficiency. The results showed that energy saving and carbon emission reduction efficiency of industries had obvious heterogeneity in Liaoning Province. The whole energy conservation and carbon emissions reduction efficiency in each industry of Liaoning Province was not high, but it presented a rising trend. Improvements of pure technical efficiency and scale efficiency were the main measures to enhance energy saving and carbon emission reduction efficiency, especially scale efficiency improvement. In order to improve the energy saving and carbon emission reduction efficiency of each industry in Liaoning Province, we put forward that Liaoning Province should adjust industry structure, encourage the development of low carbon high benefit industries, improve scientific and technological level and adjust the industry scale reasonably, meanwhile, optimize energy structure, and develop renewable and clean energy.

ORNL takes energy-efficient housing to a new level

ScienceCinema

None

2017-12-09

Oak Ridge National Laboratory, TVA and the Department of Energy are taking energy-saving research into a West Knox County neighborhood. In the Campbell Creek subdivision, ORNL researchers have helped builders to construct three homes with three different levels of energy-saving features.

101 things to do to reduce energy in every home and business. [Advertising supplement to Newsday

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This advertising supplement to Newsday features the following articles: Three Levels of Conservation; Nassau and Energy; Suffolk and Conservation; Energy Conservation and Land Use Planning; The Energy Efficient Community Program; NYSERDA Promotes Energy Efficiency and Conservation; The New York State Energy Conservation Plan; Architecture and Energy Conservation; The Engineer's Role in Energy Conservation; Energy Management Programs; a Model Energy-Efficient Home; and Choosing a Contractor. A feature also is Homeowners Energy Check List: 101 Ways to Save Money by Saving Energy. This checklist is included separately with the news supplement also. Many advertisements provide information on where to obtain energy conservationmore » equipment, specifically, solar energy systems equipment. (MCW)« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fell, Harrison; Kaffine, Daniel; Steinberg, Daniel

We investigate the role of energy efficiency in rate-based emissions intensity standards, a particularly policy-relevant consideration given that the Environmental Protection Agency's Clean Power Plan allows crediting of electricity savings as a means of complying with state-specific emissions standards. We show that with perfectly inelastic energy services demand, crediting efficiency measures can recover the first-best allocation. However, when demand for energy services exhibits some elasticity, crediting energy efficiency can no longer recover first-best. While crediting removes the relative distortion between energy generation and energy efficiency, it distorts the absolute level of energy services. Building on these results, we derive themore » conditions determining the second-best intensity standard and crediting rule. Simulations calibrated to the electricity sector in Texas find that while some form of crediting is generally welfare-improving, the proposed one-for-one crediting of energy savings is unlikely to achieve efficient outcomes.« less

Conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage.

PubMed

Kano, Shinya; Fujii, Minoru

2017-03-03

We study the conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

Energy Efficiency Improvement and Cost Saving Opportunities for the Baking Industry: An ENERGY STAR ® Guide for Plant and Energy Managers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masanet, Eric; Therkelsen, Peter; Worrell, Ernst

The U.S. baking industry—defined in this Energy Guide as facilities engaged in the manufacture of commercial bakery products such as breads, rolls, frozen cakes, pies, pastries, and cookies and crackers—consumes over $800 million worth of purchased fuels and electricity per year. Energy efficiency improvement is an important way to reduce these costs and to increase predictable earnings, especially in times of high energy price volatility. There are a variety of opportunities available at individual plants to reduce energy consumption in a cost-effective manner. This Energy Guide discusses energy efficiency practices and energy-efficient technologies that can be implemented at the component,more » process, facility, and organizational levels. Many measure descriptions include expected savings in energy and energy-related costs, based on case study data from real-world applications in food processing facilities and related industries worldwide. Typical measure payback periods and references to further information in the technical literature are also provided, when available. A summary of basic, proven measures for improving plant-level water efficiency is also provided. The information in this Energy Guide is intended to help energy and plant managers in the U.S. baking industry reduce energy and water consumption in a cost-effective manner while maintaining the quality of products manufactured. Further research on the economics of all measures—as well as on their applicability to different production practices—is needed to assess their cost effectiveness at individual plants.« less

Energy efficiency as a commodity: The emergence of a secondary market for efficiency savings in commercial buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kats, G.H.; Rosenfield, A.H.; McIntosh, T.A.

1997-06-01

The energy efficiency industry is constrained by lack of financing. For example, in the United States, commercial and public buildings need an investment of $100 billion for cost-effective retrofits with an average payback of about four years. But the current level of financing is stagnant at only about 34% of this level per year. The U.S. Department of Energy (DOE) has led the development of the North American Energy Measurement and Verification Protocol (NEMVP). This Protocol will increase the reliability and quality of estimated efficiency savings and improve realized savings. A critical element in the development of low cost financingmore » and a secondary market--whether for homes or credit card debt--is the adoption of protocols to provide uniformity and reliability of the product. This is also true of energy efficiency installations, which have been characterized by inconsistency in the installation methodologies and, frequently, unreliability of savings. This Protocol, published in April 1996, is a DOE-led effort involving American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. ASHRAE, National Association of Energy Service Companies NAESCO, National Association of Regulatory Utility Commissioners NARUC, National Association of State Energy Officials NASEO, US Environmental Protection Agency EPA, Canada`s Canadian Association of Energy Service Companies CAESCO, and Mexico`s Comision Nacional Para El Ahorro De Energia CONAE and Fideicomiso De Apoyo Al Programa De Ahorro De Energia Del Sector Electrico FIDE. DOE has begun to build on this Protocol to develop new forms of lower-cost financing including, ultimately, development of a secondary market for energy efficiency. This could double financing for building energy efficiency within five years.« less

Accessing Secondary Markets as a Capital Source for Energy Efficiency Finance Programs: Program Design Considerations for Policymakers and Administrators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kramer, C.; Martin, E. Fadrhonc; Thompson, P.

Estimates of the total opportunity for investment in cost-effective energy efficiency in the United States are typically in the range of several hundred billion dollars (Choi Granade, et al., 2009 and Fulton & Brandenburg, 2012).1,2 To access this potential, many state policymakers and utility regulators have established aggressive energy efficiency savings targets. Current levels of taxpayer and utility bill-payer funding for energy efficiency is only a small fraction of the total investment needed to meet these targets (SEE Action Financing Solutions Working Group, 2013). Given this challenge, some energy efficiency program administrators are working to access private capital sources withmore » the aim of amplifying the funds available for investment. In this context, efficient access to secondary market capital has been advanced as one important enabler of the energy efficiency industry “at scale.”3 The question of what role secondary markets can play in bringing energy efficiency to scale is largely untested despite extensive attention from media, technical publications, advocates, and others. Only a handful of transactions of energy efficiency loan products have been executed to date, and it is too soon to draw robust conclusions from these deals. At the same time, energy efficiency program administrators and policymakers face very real decisions regarding whether and how to access secondary markets as part of their energy efficiency deployment strategy.« less

An analysis of partial efficiencies of energy utilisation of different macronutrients by barramundi (Lates calcarifer) shows that starch restricts protein utilisation in carnivorous fish.

PubMed

Glencross, Brett D; Blyth, David; Bourne, Nicholas; Cheers, Susan; Irvin, Simon; Wade, Nicholas M

2017-02-01

This study examined the effect of including different dietary proportions of starch, protein and lipid, in diets balanced for digestible energy, on the utilisation efficiencies of dietary energy by barramundi (Lates calcarifer). Each diet was fed at one of three ration levels (satiety, 80 % of initial satiety and 60 % of initial satiety) for a 42-d period. Fish performance measures (weight gain, feed intake and feed conversion ratio) were all affected by dietary energy source. The efficiency of energy utilisation was significantly reduced in fish fed the starch diet relative to the other diets, but there were no significant effects between the other macronutrients. This reduction in efficiency of utilisation was derived from a multifactorial change in both protein and lipid utilisation. The rate of protein utilisation deteriorated as the amount of starch included in the diet increased. Lipid utilisation was most dramatically affected by inclusion levels of lipid in the diet, with diets low in lipid producing component lipid utilisation rates well above 1·3, which indicates substantial lipid synthesis from other energy sources. However, the energetic cost of lipid gain was as low as 0·65 kJ per kJ of lipid deposited, indicating that barramundi very efficiently store energy in the form of lipid, particularly from dietary starch energy. This study defines how the utilisation efficiency of dietary digestible energy by barramundi is influenced by the macronutrient source providing that energy, and that the inclusion of starch causes problems with protein utilisation in this species.

Smart City Energy Interconnection Technology Framework Preliminary Research

NASA Astrophysics Data System (ADS)

Zheng, Guotai; Zhao, Baoguo; Zhao, Xin; Li, Hao; Huo, Xianxu; Li, Wen; Xia, Yu

2018-01-01

to improve urban energy efficiency, improve the absorptive ratio of new energy resources and renewable energy sources, and reduce environmental pollution and other energy supply and consumption technology framework matched with future energy restriction conditions and applied technology level are required to be studied. Relative to traditional energy supply system, advanced information technology-based “Energy Internet” technical framework may give play to energy integrated application and load side interactive technology advantages, as a whole optimize energy supply and consumption and improve the overall utilization efficiency of energy.

Using learning curves on energy-efficient technologies to estimate future energy savings and emission reduction potentials in the U.S. iron and steel industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karali, Nihan; Park, Won Young; McNeil, Michael A.

Increasing concerns on non-sustainable energy use and climate change spur a growing research interest in energy efficiency potentials in various critical areas such as industrial production. This paper focuses on learning curve aspects of energy efficiency measures in the U.S iron and steel sector. A number of early-stage efficient technologies (i.e., emerging or demonstration technologies) are technically feasible and have the potential to make a significant contribution to energy saving and CO 2 emissions reduction, but fall short economically to be included. However, they may also have the cost effective potential for significant cost reduction and/or performance improvement in themore » future under learning effects such as ‘learning-by-doing’. The investigation is carried out using ISEEM, a technology oriented, linear optimization model. We investigated how steel demand is balanced with/without the availability learning curve, compared to a Reference scenario. The retrofit (or investment in some cases) costs of energy efficient technologies decline in the scenario where learning curve is applied. The analysis also addresses market penetration of energy efficient technologies, energy saving, and CO 2 emissions in the U.S. iron and steel sector with/without learning impact. Accordingly, the study helps those who use energy models better manage the price barriers preventing unrealistic diffusion of energy-efficiency technologies, better understand the market and learning system involved, predict future achievable learning rates more accurately, and project future savings via energy-efficiency technologies with presence of learning. We conclude from our analysis that, most of the existing energy efficiency technologies that are currently used in the U.S. iron and steel sector are cost effective. Penetration levels increases through the years, even though there is no price reduction. However, demonstration technologies are not economically feasible in the U.S. iron and steel sector with the current cost structure. In contrast, some of the demonstration technologies are adapted in the mid-term and their penetration levels increase as the prices go down with learning curve. We also observe large penetration of 225kg pulverized coal injection with the presence of learning.« less

Inventing an Energy Internet: Concepts, Architectures and Protocols for Smart Energy Utilization

ScienceCinema

Tsoukalas, Lefteri

2018-01-24

In recent years, the Internet is revolutionizing information availability much like the Power Grid revolutionized energy availability a century earlier. We will explore the differences and similarities of these two critical infrastructures and identify ways for convergence which may lead to an energy internet. Pricing signals, nodal forecasting, and short-term elasticities are key concepts in smart energy flows respecting the delicate equilibrium involved in generation-demand and aiming at higher efficiencies. We will discuss how intelligent forecasting approaches operating at multiple levels (including device or nodal levels) can ameliorate the challenges of power storage. In addition to higher efficiencies, an energy internet may achieve significant reliability and security improvements and offer greater flexibility and transparency in the overall energy-environmental relation.

Memristive Mixed-Signal Neuromorphic Systems: Energy-Efficient Learning at the Circuit-Level

DOE PAGES

Chakma, Gangotree; Adnan, Md Musabbir; Wyer, Austin R.; ...

2017-11-23

Neuromorphic computing is non-von Neumann computer architecture for the post Moore’s law era of computing. Since a main focus of the post Moore’s law era is energy-efficient computing with fewer resources and less area, neuromorphic computing contributes effectively in this research. Here in this paper, we present a memristive neuromorphic system for improved power and area efficiency. Our particular mixed-signal approach implements neural networks with spiking events in a synchronous way. Moreover, the use of nano-scale memristive devices saves both area and power in the system. We also provide device-level considerations that make the system more energy-efficient. The proposed systemmore » additionally includes synchronous digital long term plasticity, an online learning methodology that helps the system train the neural networks during the operation phase and improves the efficiency in learning considering the power consumption and area overhead.« less

Memristive Mixed-Signal Neuromorphic Systems: Energy-Efficient Learning at the Circuit-Level

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakma, Gangotree; Adnan, Md Musabbir; Wyer, Austin R.

Neuromorphic computing is non-von Neumann computer architecture for the post Moore’s law era of computing. Since a main focus of the post Moore’s law era is energy-efficient computing with fewer resources and less area, neuromorphic computing contributes effectively in this research. Here in this paper, we present a memristive neuromorphic system for improved power and area efficiency. Our particular mixed-signal approach implements neural networks with spiking events in a synchronous way. Moreover, the use of nano-scale memristive devices saves both area and power in the system. We also provide device-level considerations that make the system more energy-efficient. The proposed systemmore » additionally includes synchronous digital long term plasticity, an online learning methodology that helps the system train the neural networks during the operation phase and improves the efficiency in learning considering the power consumption and area overhead.« less

Energy Efficiency Roadmap for Uganda, Making Energy Efficiency Count. Executive Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

de la Rue du Can, Stephane; Pudleiner, David; Jones, David

Like many countries in Sub-Saharan Africa, Uganda has focused its energy sector investments largely on increasing energy access by increasing energy supply. The links between energy efficiency and energy access, the importance of energy efficiency in new energy supply, and the multiple benefits of energy efficiency for the level and quality of energy available, have been largely overlooked. Implementing energy efficiency in parallel with expanding both the electricity grid and new clean energy generation reduces electricity demand and helps optimize the power supply so that it can serve more customers reliably at minimum cost. Ensuring efficient appliances are incorporated intomore » energy access efforts provides improved energy services to customers. Energy efficiency is an important contributor to access to modern energy. This Energy Efficiency Roadmap for Uganda (Roadmap) is a response to the important role that electrical energy efficiency can play in meeting Uganda’s energy goals. Power Africa and the United Nations Sustainable Energy for All (SEforALL) initiatives collaborated with more than 24 stakeholders in Uganda to develop this document. The document estimates that if the most efficient technologies on the market were adopted, 2,224 gigawatt hours could be saved in 2030 across all sectors, representing 31% of the projected load. This translates into 341 megawatts of peak demand reductions, energy access to an additional 6 million rural customers and reduction of carbon dioxide emissions by 10.6 million tonnes in 2030. The Roadmap also finds that 91% of this technical potential is cost-effective, and 47% is achievable under conservative assumptions. The Roadmap prioritizes recommendations for implementing energy efficiency and maximizing benefits to meet the goals and priorities established in Uganda’s 2015 SEforALL Action Agenda. One important step is to create and increase demand for efficiency through long-term enabling policies and financial incentives combined with development of technical expertise in the labor force to allow for the promotion of new business models, such as energy service companies. A combination of enabling policies, financial schemes, regulations, enforcement, and skill development are needed to open the energy efficiency market.« less

Energy Efficiency Improvement and Cost Saving Opportunities for the Fruit and Vegetable Processing Industry. An ENERGY STAR Guide for Energy and Plant Managers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masanet, Eric; Masanet, Eric; Worrell, Ernst

2008-01-01

The U.S. fruit and vegetable processing industry--defined in this Energy Guide as facilities engaged in the canning, freezing, and drying or dehydrating of fruits and vegetables--consumes over $800 million worth of purchased fuels and electricity per year. Energy efficiency improvement isan important way to reduce these costs and to increase predictable earnings, especially in times of high energy price volatility. There are a variety of opportunities available at individual plants in the U.S. fruit and vegetable processing industry to reduce energy consumption in a cost-effective manner. This Energy Guide discusses energy efficiency practices and energy-efficient technologies that can be implementedmore » at the component, process, facility, and organizational levels. A discussion of the trends, structure, and energy consumption characteristics of the U.S. fruit and vegetable processing industry is provided along with a description of the major process technologies used within the industry. Next, a wide variety of energy efficiency measures applicable to fruit and vegetable processing plants are described. Many measure descriptions include expected savings in energy and energy-related costs, based on case study data from real-world applications in fruit and vegetable processing facilities and related industries worldwide. Typical measure payback periods and references to further information in the technical literature are also provided, when available. Given the importance of water in fruit and vegetable processing, a summary of basic, proven measures for improving plant-level water efficiency are also provided. The information in this Energy Guide is intended to help energy and plant managers in the U.S. fruit and vegetable processing industry reduce energy and water consumption in a cost-effective manner while maintaining the quality of products manufactured. Further research on the economics of all measures--as well as on their applicability to different production practices--is needed to assess their cost effectiveness at individual plants.« less

Approaches to the Organization of the Energy Efficient Activity at the Regional Level in the Context of Limited Budget Resources during the Transformation of Energy Market Paradigm

NASA Astrophysics Data System (ADS)

Vakulenko, Ihor; Myroshnychenko, Iuliia

2015-12-01

The research is devoted to the problem of the assessment of the integrated projects investment efficiency, energy saving and energy efficiency measures for social and municipal buildings within the course aimed at the reduction of the natural gas consumption and its replacement by alternative fuel types, that is important for a number of European countries, and Ukraine in particular. The objectives of the research are as follows: comparative assessment of the quality of integrated and element-by-element approaches to energy saving encompassing investment, environmental, social and organizational aspects; the formulation of practical recommendations to improve the efficiency of development and implementation of integrated programs in the field of energy saving and energy efficiency. It is proposed to use the methodology of system analysis with the elements of deduction that is practical and that allows to set key factors that influence the processes of energy replacement and energy efficiency increase, as well as factors that constrain them.

Efficient Double Auction Mechanisms in the Energy Grid with Connected and Islanded Microgrids

NASA Astrophysics Data System (ADS)

Faqiry, Mohammad Nazif

The future energy grid is expected to operate in a decentralized fashion as a network of autonomous microgrids that are coordinated by a Distribution System Operator (DSO), which should allocate energy to them in an efficient manner. Each microgrid operating in either islanded or grid-connected mode may be considered to manage its own resources. This can take place through auctions with individual units of the microgrid as the agents. This research proposes efficient auction mechanisms for the energy grid, with is-landed and connected microgrids. The microgrid level auction is carried out by means of an intermediate agent called an aggregator. The individual consumer and producer units are modeled as selfish agents. With the microgrid in islanded mode, two aggregator-level auction classes are analyzed: (i) price-heterogeneous, and (ii) price homogeneous. Under the price heterogeneity paradigm, this research extends earlier work on the well-known, single-sided Kelly mechanism to double auctions. As in Kelly auctions, the proposed algorithm implements the bidding without using any agent level private infor-mation (i.e. generation capacity and utility functions). The proposed auction is shown to be an efficient mechanism that maximizes the social welfare, i.e. the sum of the utilities of all the agents. Furthermore, the research considers the situation where a subset of agents act as a coalition to redistribute the allocated energy and price using any other specific fairness criterion. The price homogeneous double auction algorithm proposed in this research ad-dresses the problem of price-anticipation, where each agent tries to influence the equilibri-um price of energy by placing strategic bids. As a result of this behavior, the auction's efficiency is lowered. This research proposes a novel approach that is implemented by the aggregator, called virtual bidding, where the efficiency can be asymptotically maximized, even in the presence of price anticipatory bidders. Next, an auction mechanism for the energy grid, with multiple connected mi-crogrids is considered. A globally efficient bi-level auction algorithm is proposed. At the upper-level, the algorithm takes into account physical grid constraints in allocating energy to the microgrids. It is implemented by the DSO as a linear objective quadratic constraint problem that allows price heterogeneity across the aggregators. In parallel, each aggrega-tor implements its own lower-level price homogeneous auction with virtual bidding. The research concludes with a preliminary study on extending the DSO level auc-tion to multi-period day-ahead scheduling. It takes into account storage units and conven-tional generators that are present in the grid by formulating the auction as a mixed inte-ger linear programming problem.

Efficiency of fat deposition from non-starch polysaccharides, starch and unsaturated fat in pigs.

PubMed

Halas, Veronika; Babinszky, László; Dijkstra, Jan; Verstegen, Martin W A; Gerrits, Walter J J

2010-01-01

The aim was to evaluate under protein-limiting conditions the effect of different supplemental energy sources: fermentable NSP (fNSP), digestible starch (dStarch) and digestible unsaturated fat (dUFA), on marginal efficiency of fat deposition and distribution. A further aim was to determine whether the extra fat deposition from different energy sources, and its distribution in the body, depends on feeding level. A total of fifty-eight individually housed pigs (48 (SD 4) kg) were used in a 3 x 2 factorial design study, with three energy sources (0.2 MJ digestible energy (DE)/kg(0.75) per d of fNSP, dStarch and dUFA added to a control diet) at two feeding levels. Ten pigs were slaughtered at 48 (SD 4) kg body weight and treatment pigs at 106 (SD 3) kg body weight. Bodies were dissected and the chemical composition of each body fraction was determined. The effect of energy sources on fat and protein deposition was expressed relative to the control treatments within both energy intake levels based on a total of thirty-two observations in six treatments, and these marginal differences were subsequently treated as dependent variables. Results showed that preferential deposition of the supplemental energy intake in various fat depots did not depend on the energy source, and the extra fat deposition was similar at each feeding level. The marginal energetic transformation (energy retention; ER) of fNSP, dStarch and dUFA for fat retention (ERfat:DE) was 44, 52 and 49 % (P>0.05), respectively. Feeding level affected fat distribution, but source of energy did not change the relative partitioning of fat deposition. The present results do not support values of energetic efficiencies currently used in net energy-based systems.

Technology Prioritization: Transforming the U.S. Building Stock to Embrace Energy Efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Farese, Philip; Abramson, Alexis

2013-01-01

The U.S. Buildings sector is responsible for about 40% of the national energy expenditures. This is due in part to wasteful use of resources and limited considerations made for energy efficiency during the design and retrofit phases. Recent studies have indicated the potential for up to 30-50% energy savings in the U.S. buildings sector using currently available technologies. This paper discusses efforts to accelerate the transformation in the U.S. building energy efficiency sector using a new technology prioritization framework. The underlying analysis examines building energy use micro segments using the Energy Information Administration Annual Energy Outlook and other publically availablemore » information. The tool includes a stock-and-flow model to track stock vintage and efficiency levels with time. The tool can be used to investigate energy efficiency measures under a variety of scenarios and has a built-in energy accounting framework to prevent double counting of energy savings within any given portfolio. This tool is developed to inform decision making and estimate long term potential energy savings for different market adoption scenarios.« less

2010 Northwest Federal Market Assessment Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scanlon, Tim; Sandusky, William F.

The primary intent of this market assessment is to provide insights on the effectiveness of current energy efficiency and renewable energy program offerings available to Federal sites in the region. The level of detail, quality and currency of the data used in this market assessment varies significantly by Federal agency and energy efficiency service provider. Limited access to some Federal sites, limited availability of key points of contact, time/resource constraints, and other considerations limited the total number of Federal agencies and energy efficiency service providers participating in the survey.

Home energy efficiency and radon related risk of lung cancer: modelling study

PubMed Central

Milner, James; Shrubsole, Clive; Das, Payel; Jones, Benjamin; Ridley, Ian; Chalabi, Zaid; Hamilton, Ian; Armstrong, Ben; Davies, Michael

2014-01-01

Objective To investigate the effect of reducing home ventilation as part of household energy efficiency measures on deaths from radon related lung cancer. Design Modelling study. Setting England. Intervention Home energy efficiency interventions, motivated in part by targets for reducing greenhouse gases, which entail reduction in uncontrolled ventilation in keeping with good practice guidance. Main outcome measures Modelled current and future distributions of indoor radon levels for the English housing stock and associated changes in life years due to lung cancer mortality, estimated using life tables. Results Increasing the air tightness of dwellings (without compensatory purpose-provided ventilation) increased mean indoor radon concentrations by an estimated 56.6%, from 21.2 becquerels per cubic metre (Bq/m3) to 33.2 Bq/m3. After the lag in lung cancer onset, this would result in an additional annual burden of 4700 life years lost and (at peak) 278 deaths. The increases in radon levels for the millions of homes that would contribute most of the additional burden are below the threshold at which radon remediation measures are cost effective. Fitting extraction fans and trickle ventilators to restore ventilation will help offset the additional burden but only if the ventilation related energy efficiency gains are lost. Mechanical ventilation systems with heat recovery may lower radon levels and the risk of cancer while maintaining the advantage of energy efficiency for the most airtight dwellings but there is potential for a major adverse impact on health if such systems fail. Conclusion Unless specific remediation is used, reducing the ventilation of dwellings will improve energy efficiency only at the expense of population wide adverse impact on indoor exposure to radon and risk of lung cancer. The implications of this and other consequences of changes to ventilation need to be carefully evaluated to ensure that the desirable health and environmental benefits of home energy efficiency are not compromised by avoidable negative impacts on indoor air quality. PMID:24415631

Specification of Energy Assessment Methodologies to Satisfy ISO 50001 Energy Management Standard

NASA Astrophysics Data System (ADS)

Kanneganti, Harish

Energy management has become more crucial for industrial sector as a way to lower their cost of production and in reducing their carbon footprint. Environmental regulations also force the industrial sector to increase the efficiency of their energy usage. Hence industrial sector started relying on energy management consultancies for improvements in energy efficiency. With the development of ISO 50001 standard, the entire energy management took a new dimension involving top level management and getting their commitment on energy efficiency. One of the key requirements of ISO 50001 is to demonstrate continual improvement in their (industry) energy efficiency. The major aim of this work is to develop an energy assessment methodology and reporting format to tailor the needs of ISO 50001. The developed methodology integrates the energy reduction aspect of an energy assessment with the requirements of sections 4.4.3 (Energy Review) to 4.4.6 (Objectives, Targets and Action Plans) in ISO 50001 and thus helping the facilities in easy implementation of ISO 50001.

Energy partitioning and thyroid hormone levels during Salmonella enteritidis infections in pullets with high or low residual feed intake.

PubMed

Van Eerden, E; Van Den Brand, H; Heetkamp, M J W; Decuypere, E; Kemp, B

2006-10-01

This experiment was conducted to investigate whether feed efficiency, as measured by residual feed intake as a phenotypic trait, affects energy partitioning in pullets that have received Salmonella inoculation as an immune challenge. In each of 8 trials, energy partitioning was measured during 5 wk in 15-wk-old efficient (R-) and nonefficient (R+) pullets, which were housed per efficiency group in 2 identical climate respiration chambers. After 1 wk of adaptation, the pullets in 4 trials were orally inoculated with 10(8) cfu of Salmonella enteritidis; pullets in the remaining trials were not inoculated and served as controls. Heat production was calculated from continuous recordings of O(2) consumption and CO(2) production. Energy and N partitioning were recorded on a weekly basis. Blood samples for analyses on thyroid hormones were taken at 16, 17, and 19 wk of age. There were no interactions between efficiency type and Salmonella treatment or Salmonella treatment effects in energy partitioning, except for a short-term increase in heat production in inoculated pullets. Nonefficient pullets had higher gross energy and ME intake, higher estimated ME for maintenance, lower ME:gross energy ratio, and higher total heat production and nonactivity-related heat production compared with R- pullets. Triiodothyronine levels in R+ pullets were higher at 16 and 17 wk but were lower at 19 wk of age compared with R- pullets. Thyroxine levels were higher in R- at 16 wk and showed interactions between efficiency type and Salmonella treatment at 17 and 19 wk of age. Body weights and spleen weights did not differ between efficiency groups. Nonefficient pullets had higher heart, liver, and ovary weights and more large yellow follicles than R- pullets. There were no Salmonella effects on body and organ weights. We conclude that R+ pullets have a faster running energy metabolism and that they put more resources into organ development than R- pullets. Inoculation with Salmonella has a short-term effect on nonactivity-related heat production but does not affect energy partitioning, regardless of efficiency type.

Energy-efficient neural information processing in individual neurons and neuronal networks.

PubMed

Yu, Lianchun; Yu, Yuguo

2017-11-01

Brains are composed of networks of an enormous number of neurons interconnected with synapses. Neural information is carried by the electrical signals within neurons and the chemical signals among neurons. Generating these electrical and chemical signals is metabolically expensive. The fundamental issue raised here is whether brains have evolved efficient ways of developing an energy-efficient neural code from the molecular level to the circuit level. Here, we summarize the factors and biophysical mechanisms that could contribute to the energy-efficient neural code for processing input signals. The factors range from ion channel kinetics, body temperature, axonal propagation of action potentials, low-probability release of synaptic neurotransmitters, optimal input and noise, the size of neurons and neuronal clusters, excitation/inhibition balance, coding strategy, cortical wiring, and the organization of functional connectivity. Both experimental and computational evidence suggests that neural systems may use these factors to maximize the efficiency of energy consumption in processing neural signals. Studies indicate that efficient energy utilization may be universal in neuronal systems as an evolutionary consequence of the pressure of limited energy. As a result, neuronal connections may be wired in a highly economical manner to lower energy costs and space. Individual neurons within a network may encode independent stimulus components to allow a minimal number of neurons to represent whole stimulus characteristics efficiently. This basic principle may fundamentally change our view of how billions of neurons organize themselves into complex circuits to operate and generate the most powerful intelligent cognition in nature. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Phased Retrofits in Existing Homes in Florida Phase I: Shallow and Deep Retrofits

DOE Office of Scientific and Technical Information (OSTI.GOV)

D. Parker; Sutherland, K.; Chasar, D.

2016-02-01

The U.S. Department of Energy (DOE) Building America program, in collaboration with Florida Power and Light (FPL), conducted a phased residential energy-efficiency retrofit program. This research sought to establish impacts on annual energy and peak energy reductions from the technologies applied at two levels of retrofit - shallow and deep, with savings levels approaching the Building America program goals of reducing whole-house energy use by 40%. Under the Phased Deep Retrofit (PDR) project, we have installed phased, energy-efficiency retrofits in a sample of 56 existing, all-electric homes. End-use savings and economic evaluation results from the phased measure packages and singlemore » measures are summarized in this report.« less

Study on Laws, Regulations and Standards on Energy Efficiency, Energy Conserving and Emission Reduction of Industrial Boilers in EU

NASA Astrophysics Data System (ADS)

Liu, Ren; Zhao, Yuejin; Chen, Haihong; Liang, Xiuying; Yang, Ming

2017-12-01

Industrial boilers are widely applied in such fields as factory power, building heating, and people’s lives; China is the world’s largest producer and user of industrial boilers, with very high annual energy consumption; clear requirements have been put forward by China on the energy efficiency since the “11th Five-year Plan” with the hope to save energy and reduce emission by means of energy efficiency standards and regulations on the supervision and control of various special equipment. So far, the energy efficiency of industrial boilers in China has been improved significantly but there is still a gap with the EU states. This paper analyzes the policies of energy efficiency, implementation models and methods of supervision and implementation at the EU level from laws, regulations, directives as well as standards; the paper also puts forward suggestions of energy conserving and emission reduction on the improvement of energy conserving capacity of industrial boilers in China through studying the legislations and measures of the developed countries in energy conserving of boilers.

Indoor radon problem in energy efficient multi-storey buildings.

PubMed

Yarmoshenko, I V; Vasilyev, A V; Onishchenko, A D; Kiselev, S M; Zhukovsky, M V

2014-07-01

Modern energy-efficient architectural solutions and building construction technologies such as monolithic concrete structures in combination with effective insulation reduce air permeability of building envelope. As a result, air exchange rate is significantly reduced and conditions for increased radon accumulation in indoor air are created. Based on radon survey in Ekaterinburg, Russia, remarkable increase in indoor radon concentration level in energy-efficient multi-storey buildings was found in comparison with similar buildings constructed before the-energy-saving era. To investigate the problem of indoor radon in energy-efficient multi-storey buildings, the measurements of radon concentration have been performed in seven modern buildings using radon monitoring method. Values of air exchange rate and other parameters of indoor climate in energy-efficient buildings have been estimated. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salasovich, James; LoVullo, David; Kandt, Alicen

This report summarizes results from the energy efficiency, water efficiency, and renewable energy site assessment of the Mendenhall Glacier Visitor Center and site in Juneau, Alaska. The assessment is an American Society of Heating, Refrigerating, and Air-Conditioning Engineers Level 2 audit and meets Energy Independence and Security Act requirements. A team led by the U.S. Department of Energy's National Renewable Energy Laboratory conducted the assessment with U.S. Forest Service personnel August 19-20, 2015, as part of ongoing efforts by USFS to reduce energy and water use.

An Energy Efficient Protocol For The Internet Of Things

NASA Astrophysics Data System (ADS)

Venčkauskas, Algimantas; Jusas, Nerijus; Kazanavičius, Egidijus; Štuikys, Vytautas

2015-01-01

The Internet of Things (IoT) is a technological revolution that represents the future of computing and communications. One of the most important challenges of IoT is security: protection of data and privacy. The SSL protocol is the de-facto standard for secure Internet communications. The extra energy cost of encrypting and authenticating of the application data with SSL is around 15%. For IoT devices, where energy resources are limited, the increase in the cost of energy is a very significant factor. In this paper we present the energy efficient SSL protocol which ensures the maximum bandwidth and the required level of security with minimum energy consumption. The proper selection of the security level and CPU multiplier, can save up to 85% of the energy required for data encryption.

A system-level mathematical model for evaluation of power train performance of load-leveled electric-vehicles

NASA Technical Reports Server (NTRS)

Purohit, G. P.; Leising, C. J.

1984-01-01

The power train performance of load leveled electric vehicles can be compared with that of nonload leveled systems by use of a simple mathematical model. This method of measurement involves a number of parameters including the degree of load leveling and regeneration, the flywheel mechanical to electrical energy fraction, and efficiencies of the motor, generator, flywheel, and transmission. Basic efficiency terms are defined and representative comparisons of a variety of systems are presented. Results of the study indicate that mechanical transfer of energy into and out of the flywheel is more advantageous than electrical transfer. An optimum degree of load leveling may be achieved in terms of the driving cycle, battery characteristics, mode of mechanization, and the efficiency of the components. For state of the art mechanically coupled flyheel systems, load leveling losses can be held to a reasonable 10%; electrically coupled systems can have losses that are up to six times larger. Propulsion system efficiencies for mechanically coupled flywheel systems are predicted to be approximately the 60% achieved on conventional nonload leveled systems.

NASA technology utilization house

NASA Technical Reports Server (NTRS)

1977-01-01

Following systems and features, which are predicted to save approximately $20,000 in utility costs over twenty year period, are incorporated into single-level, contemporarily designed, energy efficient residential structure: solar heating and cooling; energy efficient appliances; water recycling; security, smoke, and tornado detectors; and flat conductor electrical wiring.

Climate stabilization wedges in action: a systems approach to energy sustainability for Hawaii Island.

PubMed

Johnson, Jeremiah; Chertow, Marian

2009-04-01

Pacala and Socolow developed a framework to stabilize global greenhouse gas levels for the next fifty years using wedges of constant size representing an increasing use of existing technologies and approaches for energy efficiency, carbon free generation, renewables, and carbon storage. The research presented here applies their approach to Hawaii Island, with modifications to support local scale analysis and employing a "bottom-up" methodology that allows for wedges of various sizes. A discretely bounded spatial unit offers a testing ground for a holistic approach to improving the energy sector with the identification of local options and limitations to the implementation of a comprehensive energy strategy. Nearly 80% of total primary energy demand across all sectors for Hawaii Island is currently met using petroleum-based fuels.The Sustainable Energy Plan scenario included here presents an internally consistent set of recommendations bounded by local constraints in areas such as transportation efficiency, centralized renewable generation (e.g., geothermal, wind), reduction in transmission losses, and improved building efficiency. This scenario shows thatthe demand for primary energy in 2030 could be reduced by 23% through efficiency measures while 46% could be met by renewable generation, resulting in only 31% of the projected demand being met by fossil fuels. In 2030, the annual releases of greenhouse gases would be 3.2 Mt CO2-eq/year under the Baseline scenario, while the Sustainable Energy Plan would reduce this to 1.2 Mt CO2-eq/year--an annual emissions rate 40% below 2006 levels and 10% below 1990 levels. The total for greenhouse gas emissions during the 24-year study period (2007 to 2030) is 59.9 Mt CO2-eq under the Baseline scenario and 32.5 Mt CO2-eq under the Sustainable Energy Plan scenario. Numerous combinations of efficiency and renewable energy options can be employed in a manner that stabilizes the greenhouse gas emissions of Hawaii Island.

Cache Energy Optimization Techniques For Modern Processors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mittal, Sparsh

2013-01-01

Modern multicore processors are employing large last-level caches, for example Intel's E7-8800 processor uses 24MB L3 cache. Further, with each CMOS technology generation, leakage energy has been dramatically increasing and hence, leakage energy is expected to become a major source of energy dissipation, especially in last-level caches (LLCs). The conventional schemes of cache energy saving either aim at saving dynamic energy or are based on properties specific to first-level caches, and thus these schemes have limited utility for last-level caches. Further, several other techniques require offline profiling or per-application tuning and hence are not suitable for product systems. In thismore » book, we present novel cache leakage energy saving schemes for single-core and multicore systems; desktop, QoS, real-time and server systems. Also, we present cache energy saving techniques for caches designed with both conventional SRAM devices and emerging non-volatile devices such as STT-RAM (spin-torque transfer RAM). We present software-controlled, hardware-assisted techniques which use dynamic cache reconfiguration to configure the cache to the most energy efficient configuration while keeping the performance loss bounded. To profile and test a large number of potential configurations, we utilize low-overhead, micro-architecture components, which can be easily integrated into modern processor chips. We adopt a system-wide approach to save energy to ensure that cache reconfiguration does not increase energy consumption of other components of the processor. We have compared our techniques with state-of-the-art techniques and have found that our techniques outperform them in terms of energy efficiency and other relevant metrics. The techniques presented in this book have important applications in improving energy-efficiency of higher-end embedded, desktop, QoS, real-time, server processors and multitasking systems. This book is intended to be a valuable guide for both newcomers and veterans in the field of cache power management. It will help graduate students, CAD tool developers and designers in understanding the need of energy efficiency in modern computing systems. Further, it will be useful for researchers in gaining insights into algorithms and techniques for micro-architectural and system-level energy optimization using dynamic cache reconfiguration. We sincerely believe that the ``food for thought'' presented in this book will inspire the readers to develop even better ideas for designing ``green'' processors of tomorrow.« less

Application configuration selection for energy-efficient execution on multicore systems

DOE PAGES

Wang, Shinan; Luo, Bing; Shi, Weisong; ...

2015-09-21

Balanced performance and energy consumption are incorporated in the design of modern computer systems. Several runtime factors, such as concurrency levels, thread mapping strategies, and dynamic voltage and frequency scaling (DVFS) should be considered in order to achieve optimal energy efficiency fora workload. Selecting appropriate run-time factors, however, is one of the most challenging tasks because the run-time factors are architecture-specific and workload-specific. And while most existing works concentrate on either static analysis of the workload or run-time prediction results, we present a hybrid two-step method that utilizes concurrency levels and DVFS settings to achieve the energy efficiency configuration formore » a worldoad. The experimental results based on a Xeon E5620 server with NPB and PARSEC benchmark suites show that the model is able to predict the energy efficient configuration accurately. On average, an additional 10% EDP (Energy Delay Product) saving is obtained by using run-time DVFS for the entire system. An off-line optimal solution is used to compare with the proposed scheme. Finally, the experimental results show that the average extra EDP saved by the optimal solution is within 5% on selective parallel benchmarks.« less

Energy efficient engine sector combustor rig test program

NASA Technical Reports Server (NTRS)

Dubiel, D. J.; Greene, W.; Sundt, C. V.; Tanrikut, S.; Zeisser, M. H.

1981-01-01

Under the NASA-sponsored Energy Efficient Engine program, Pratt & Whitney Aircraft has successfully completed a comprehensive combustor rig test using a 90-degree sector of an advanced two-stage combustor with a segmented liner. Initial testing utilized a combustor with a conventional louvered liner and demonstrated that the Energy Efficient Engine two-stage combustor configuration is a viable system for controlling exhaust emissions, with the capability to meet all aerothermal performance goals. Goals for both carbon monoxide and unburned hydrocarbons were surpassed and the goal for oxides of nitrogen was closely approached. In another series of tests, an advanced segmented liner configuration with a unique counter-parallel FINWALL cooling system was evaluated at engine sea level takeoff pressure and temperature levels. These tests verified the structural integrity of this liner design. Overall, the results from the program have provided a high level of confidence to proceed with the scheduled Combustor Component Rig Test Program.

Efficient Charge Transfer and Fine-Tuned Energy Level Alignment in a THF-Processed Fullerene-Free Organic Solar Cell with 11.3% Efficiency.

PubMed

Zheng, Zhong; Awartani, Omar M; Gautam, Bhoj; Liu, Delong; Qin, Yunpeng; Li, Wanning; Bataller, Alexander; Gundogdu, Kenan; Ade, Harald; Hou, Jianhui

2017-02-01

Fullerene-free organic solar cells show over 11% power conversion efficiency, processed by low toxic solvents. The applied donor and acceptor in the bulk heterojunction exhibit almost the same highest occupied molecular orbital level, yet exhibit very efficient charge creation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy Efficiency for Automotive Instructors.

ERIC Educational Resources Information Center

Scharmann, Larry, Ed.; Lay, Gary, Ed.

Intended primarily but not solely for use at the postsecondary level, this curriculum guide contains six units on energy efficiency that were designed to be incorporated into an existing program in automobile mechanics. The following topics are examined: drivers and public awareness (relationship between driving and fuel consumption); ignition…

Induction Consolidation of Thermoplastic Composites Using Smart Susceptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsen, Marc R

2012-06-14

This project has focused on the area of energy efficient consolidation and molding of fiber reinforced thermoplastic composite components as an energy efficient alternative to the conventional processing methods such as autoclave processing. The expanding application of composite materials in wind energy, automotive, and aerospace provides an attractive energy efficiency target for process development. The intent is to have this efficient processing along with the recyclable thermoplastic materials ready for large scale application before these high production volume levels are reached. Therefore, the process can be implemented in a timely manner to realize the maximum economic, energy, and environmental efficiencies.more » Under this project an increased understanding of the use of induction heating with smart susceptors applied to consolidation of thermoplastic has been achieved. This was done by the establishment of processing equipment and tooling and the subsequent demonstration of this fabrication technology by consolidating/molding of entry level components for each of the participating industrial segments, wind energy, aerospace, and automotive. This understanding adds to the nation's capability to affordably manufacture high quality lightweight high performance components from advanced recyclable composite materials in a lean and energy efficient manner. The use of induction heating with smart susceptors is a precisely controlled low energy method for the consolidation and molding of thermoplastic composites. The smart susceptor provides intrinsic thermal control based on the interaction with the magnetic field from the induction coil thereby producing highly repeatable processing. The low energy usage is enabled by the fact that only the smart susceptor surface of the tool is heated, not the entire tool. Therefore much less mass is heated resulting in significantly less required energy to consolidate/mold the desired composite components. This energy efficiency results in potential energy savings of {approx}75% as compared to autoclave processing in aerospace, {approx}63% as compared to compression molding in automotive, and {approx}42% energy savings as compared to convectively heated tools in wind energy. The ability to make parts in a rapid and controlled manner provides significant economic advantages for each of the industrial segments. These attributes were demonstrated during the processing of the demonstration components on this project.« less

Energy in the environment and the second law of thermodynamics

NASA Technical Reports Server (NTRS)

Mueller, R. F.

1972-01-01

The relationship between the consumption of energy by technological cultures and the second law of thermodynamics is discussed. The analysis is based on a description of the operation of a mechanical device which consumes energy. It is concluded that the flow of energy in manifold spontaneous conditions, which play a vital role in the operation of any technological process, remove most of the energy flow path from the control of the operator. It is stated that the increased efficiency of a process can benefit the environment only as much as this efficiency enables the total energy input to be reduced for a given level of production and increasing efficiency cannot meet the problems of an increased rate of energy utilization.

Energy efficient engine

NASA Technical Reports Server (NTRS)

Burrus, D.; Sabla, P. E.; Bahr, D. W.

1980-01-01

The feasibility of meeting or closely approaching the emissions goals established for the Energy Efficient Engine (E3) Project with an advanced design, single annular combustor was determined. A total of nine sector combustor configurations and one full-annular-combustor configuration were evaluated. Acceptable levels of carbon monoxide and hydrocarbon emissions were obtained with several of the sector combustor configurations tested, and several of the configurations tested demonstrated reduced levels of nitrogen oxides compared to conventional, single annular designs. None of the configurations tested demonstrated nitrogen oxide emission levels that meet the goal of the E3 Project.

IDEN2-A program for visual identification of spectral lines and energy levels in optical spectra of atoms and simple molecules

NASA Astrophysics Data System (ADS)

Azarov, V. I.; Kramida, A.; Vokhmentsev, M. Ya.

2018-04-01

The article describes a Java program that can be used in a user-friendly way to visually identify spectral lines observed in complex spectra with theoretically predicted transitions between atomic or molecular energy levels. The program arranges various information about spectral lines and energy levels in such a way that line identification and determination of positions of experimentally observed energy levels become much easier tasks that can be solved fast and efficiently.

The pressure cold wind system on the impact of industrial boiler economy and security

NASA Astrophysics Data System (ADS)

Li, Henan; Qian, Hongli; Jiang, Lei; Yu, Dekai; Li, Guannan; Yuan, Hong

2017-05-01

Industrial boiler is one of the most energy-consuming equipment in china, the annual consumption of energy accounts for about one-third of the national energy consumption.Industrial boiler in service at present have several severe problems such as small capacity, low efficiency, high energy consumption and causing severe pollution on environment, the average industrial boiler operation efficiency is only 65%. If the efficiency increased by 15% ∼ 20%, which meet the international advanced level, each year 70 million tons of coal saving and reduce environmental pollution[1]. As energy conservation and emissions reduction becomes the basic national policy of our country, improving the efficiency of industrial boiler energy is facing opportunities and challenges, optimizing the operation mode of the existing units, it is necessary to increase the flexibility of the boiler control.

Improving building energy efficiency in India: State-level analysis of building energy efficiency policies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Sha; Tan, Qing; Evans, Meredydd

India is expected to add 40 billion m2 of new buildings till 2050. Buildings are responsible for one third of India’s total energy consumption today and building energy use is expected to continue growing driven by rapid income and population growth. The implementation of the Energy Conservation Building Code (ECBC) is one of the measures to improve building energy efficiency. Using the Global Change Assessment Model, this study assesses growth in the buildings sector and impacts of building energy policies in Gujarat, which would help the state adopt ECBC and expand building energy efficiency programs. Without building energy policies, buildingmore » energy use in Gujarat would grow by 15 times in commercial buildings and 4 times in urban residential buildings between 2010 and 2050. ECBC improves energy efficiency in commercial buildings and could reduce building electricity use in Gujarat by 20% in 2050, compared to the no policy scenario. Having energy codes for both commercial and residential buildings could result in additional 10% savings in electricity use. To achieve these intended savings, it is critical to build capacity and institution for robust code implementation.« less

Inventing an Energy Internet: Concepts, Architectures and Protocols for Smart Energy Utilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsoukalas, Lefteri

2009-04-29

In recent years, the Internet is revolutionizing information availability much like the Power Grid revolutionized energy availability a century earlier. We will explore the differences and similarities of these two critical infrastructures and identify ways for convergence which may lead to an energy internet. Pricing signals, nodal forecasting, and short-term elasticities are key concepts in smart energy flows respecting the delicate equilibrium involved in generation-demand and aiming at higher efficiencies. We will discuss how intelligent forecasting approaches operating at multiple levels (including device or nodal levels) can ameliorate the challenges of power storage. In addition to higher efficiencies, an energymore » internet may achieve significant reliability and security improvements and offer greater flexibility and transparency in the overall energy-environmental relation.« less

An Evaluation of the Consumer Costs and Benefits of Energy Efficiency Resource Standards

NASA Astrophysics Data System (ADS)

Lessans, Mark D.

Of the modern-day policies designed to encourage energy efficiency, one with a significant potential for impact is that of Energy Efficiency Resource Standards (EERS). EERS policies place the responsibility for meeting an efficiency target on the electric and gas utilities, typically setting requirements for annual reductions in electricity generation or gas distribution to customers as a percentage of sales. To meet these requirements, utilities typically implement demand-side management (DSM) programs, which encourage energy efficiency at the customer level through incentives and educational initiatives. In Maryland, a statewide EERS has provided for programs which save a significant amount of energy, but is ultimately falling short in meeting the targets established by the policy. This study evaluates residential DSM programs offered by Pepco, a utility in Maryland, for cost-effectiveness. However, unlike most literature on the topic, analysis focuses on the costs-benefit from the perspective of the consumer, and not the utility. The results of this study are encouraging: the majority of programs analyzed show that the cost of electricity saved, or levelized cost of saved energy (LCSE), is less expensive than the current retail cost of electricity cost in Maryland. A key goal of this study is to establish a metric for evaluating the consumer cost-effectiveness of participation in energy efficiency programs made available by EERS. In doing so, the benefits of these programs can be effectively marketed to customers, with the hope that participation will increase. By increasing consumer awareness and buy-in, the original goals set out through EERS can be realized and the policies can continue to receive support.

Time-Varying Value of Energy Efficiency in Michigan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mims, Natalie; Eckman, Tom; Schwartz, Lisa C.

Quantifying the time-varying value of energy efficiency is necessary to properly account for all of its benefits and costs and to identify and implement efficiency resources that contribute to a low-cost, reliable electric system. Historically, most quantification of the benefits of efficiency has focused largely on the economic value of annual energy reduction. Due to the lack of statistically representative metered end-use load shape data in Michigan (i.e., the hourly or seasonal timing of electricity savings), the ability to confidently characterize the time-varying value of energy efficiency savings in the state, especially for weather-sensitive measures such as central air conditioning,more » is limited. Still, electric utilities in Michigan can take advantage of opportunities to incorporate the time-varying value of efficiency into their planning. For example, end-use load research and hourly valuation of efficiency savings can be used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service (KEMA 2012). In addition, accurately calculating the time-varying value of efficiency may help energy efficiency program administrators prioritize existing offerings, set incentive or rebate levels that reflect the full value of efficiency, and design new programs.« less

Development of a differentially balanced magnetic bearing and control system for use with a flywheel energy storage system

NASA Technical Reports Server (NTRS)

Higgins, Mark A.; Plant, David P.; Ries, Douglas M.; Kirk, James A.; Anand, Davinder K.

1992-01-01

The purpose of a magnetically suspended flywheel energy storage system for electric utility load leveling is to provide a means to store energy during times when energy is inexpensive to produce and then return it to the customer during times of peak power demand when generated energy is most expensive. The design of a 20 kWh flywheel energy storage system for electric utility load leveling applications involves the successful integration of a number of advanced technologies so as to minimize the size and cost of the system without affecting its efficiency and reliability. The flywheel energy storage system uses a carbon epoxy flywheel, two specially designed low loss magnetic bearings, a high efficiency motor generator, and a 60 cycle AC power converter all integrated through a microprocessor controller. The basic design is discussed of each of the components that is used in the energy storage design.

Light Increases Energy Transfer Efficiency in a Boreal Stream

PubMed Central

Lesutienė, Jūratė; Gorokhova, Elena; Stankevičienė, Daiva; Bergman, Eva; Greenberg, Larry

2014-01-01

Periphyton communities of a boreal stream were exposed to different light and nutrient levels to estimate energy transfer efficiency from primary to secondary producers using labeling with inorganic 13C. In a one-day field experiment, periphyton grown in fast-flow conditions and dominated by opportunistic green algae were exposed to light levels corresponding to sub-saturating (forest shade) and saturating (open stream section) irradiances, and to N and P nutrient additions. In a two-week laboratory experiment, periphyton grown in low-flow conditions and dominated by slowly growing diatoms were incubated under two sub-saturating light and nutrient enrichment levels as well as grazed and non-grazed conditions. Light had significant positive effect on 13C uptake by periphyton. In the field experiment, P addition had a positive effect on 13C uptake but only at sub-saturating light levels, whereas in the laboratory experiment nutrient additions had no effect on the periphyton biomass, 13C uptake, biovolume and community composition. In the laboratory experiment, the grazer (caddisfly) effect on periphyton biomass specific 13C uptake and nutrient content was much stronger than the effects of light and nutrients. In particular, grazers significantly reduced periphyton biomass and increased biomass specific 13C uptake and C:nutrient ratios. The energy transfer efficiency, estimated as a ratio between 13C uptake by caddisfly and periphyton, was positively affected by light conditions, whereas the nutrient effect was not significant. We suggest that the observed effects on energy transfer were related to the increased diet contribution of highly palatable green algae, stimulated by higher light levels. Also, high heterotrophic microbial activity under low light levels would facilitate energy loss through respiration and decrease overall trophic transfer efficiency. These findings suggest that even a small increase in light intensity could result in community-wide effects on periphyton in boreal streams, with a subsequent increase in energy transfer and system productivity. PMID:25412343

China's Pathways to Achieving 40% ~ 45% Reduction in CO{sub 2} Emissions per Unit of GDP in 2020: Sectoral Outlook and Assessment of Savings Potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Nina; Fridley, David; Zhou, Nan

2011-09-30

Achieving China’s goal of reducing its carbon intensity (CO{sub 2} per unit of GDP) by 40% to 45% percent below 2005 levels by 2020 will require the strengthening and expansion of energy efficiency policies across the buildings, industries and transport sectors. This study uses a bottom-up, end-use model and two scenarios -- an enhanced energy efficiency (E3) scenario and an alternative maximum technically feasible energy efficiency improvement (Max Tech) scenario – to evaluate what policies and technical improvements are needed to achieve the 2020 carbon intensity reduction target. The findings from this study show that a determined approach by Chinamore » can lead to the achievement of its 2020 goal. In particular, with full success in deepening its energy efficiency policies and programs but following the same general approach used during the 11th Five Year Plan, it is possible to achieve 49% reduction in CO{sub 2} emissions per unit of GDP (CO{sub 2} emissions intensity) in 2020 from 2005 levels (E3 case). Under the more optimistic but feasible assumptions of development and penetration of advanced energy efficiency technology (Max Tech case), China could achieve a 56% reduction in CO{sub 2} emissions intensity in 2020 relative to 2005 with cumulative reduction of energy use by 2700 Mtce and of CO{sub 2} emissions of 8107 Mt CO{sub 2} between 2010 and 2020. Energy savings and CO{sub 2} mitigation potential varies by sector but most of the energy savings potential is found in energy-intensive industry. At the same time, electricity savings and the associated emissions reduction are magnified by increasing renewable generation and improving coal generation efficiency, underscoring the dual importance of end-use efficiency improvements and power sector decarbonization.« less

Market leadership by example: Government sector energy efficiency in developing countries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Wie McGrory, Laura; Harris, Jeffrey; Breceda, Miguel

2002-05-20

Government facilities and services are often the largest energy users and major purchasers of energy-using equipment within a country. In developing as well as industrial countries, government ''leadership by example'' can be a powerful force to shift the market toward energy efficiency, complementing other elements of a national energy efficiency strategy. Benefits from more efficient energy management in government facilities and operations include lower government energy bills, reduced greenhouse gas emissions, less demand on electric utility systems, and in many cases reduced dependence on imported oil. Even more significantly, the government sector's buying power and example to others can generatemore » broader demand for energy-efficient products and services, creating entry markets for domestic suppliers and stimulating competition in providing high-efficiency products and services. Despite these benefits, with the exception of a few countries government sector actions have often lagged behind other energy efficiency policies. This is especially true in developing countries and transition economies - even though energy used by public agencies in these countries may represent at least as large a share of total energy use as the public sector in industrial economies. This paper summarizes work in progress to inventory current programs and policies for government sector energy efficiency in developing countries, and describes successful case studies from Mexico's implementation of energy management in the public sector. We show how these policies in Mexico, begun at the federal level, have more recently been extended to state and local agencies, and consider the applicability of this model to other developing countries.« less

Accelerating the deployment of energy efficient and renewable energy technologies in South Africa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shickman, Kurt

Purpose of the project was to accelerate the deployment of energy efficient and renewable energy technologies in South Africa. Activities were undertaken to reduce barriers to deployment by improving product awareness for the South African market; market and policy intelligence for U.S. manufacturers; product/service availability; local technical capacity at the workforce, policymaker and expert levels; and ease of conducting business for these technologies/services in the South African market.

Evaluating architecture impact on system energy efficiency

PubMed Central

Yu, Shijie; Wang, Rui; Luan, Zhongzhi; Qian, Depei

2017-01-01

As the energy consumption has been surging in an unsustainable way, it is important to understand the impact of existing architecture designs from energy efficiency perspective, which is especially valuable for High Performance Computing (HPC) and datacenter environment hosting tens of thousands of servers. One obstacle hindering the advance of comprehensive evaluation on energy efficiency is the deficient power measuring approach. Most of the energy study relies on either external power meters or power models, both of these two methods contain intrinsic drawbacks in their practical adoption and measuring accuracy. Fortunately, the advent of Intel Running Average Power Limit (RAPL) interfaces has promoted the power measurement ability into next level, with higher accuracy and finer time resolution. Therefore, we argue it is the exact time to conduct an in-depth evaluation of the existing architecture designs to understand their impact on system energy efficiency. In this paper, we leverage representative benchmark suites including serial and parallel workloads from diverse domains to evaluate the architecture features such as Non Uniform Memory Access (NUMA), Simultaneous Multithreading (SMT) and Turbo Boost. The energy is tracked at subcomponent level such as Central Processing Unit (CPU) cores, uncore components and Dynamic Random-Access Memory (DRAM) through exploiting the power measurement ability exposed by RAPL. The experiments reveal non-intuitive results: 1) the mismatch between local compute and remote memory node caused by NUMA effect not only generates dramatic power and energy surge but also deteriorates the energy efficiency significantly; 2) for multithreaded application such as the Princeton Application Repository for Shared-Memory Computers (PARSEC), most of the workloads benefit a notable increase of energy efficiency using SMT, with more than 40% decline in average power consumption; 3) Turbo Boost is effective to accelerate the workload execution and further preserve the energy, however it may not be applicable on system with tight power budget. PMID:29161317

Evaluating architecture impact on system energy efficiency.

PubMed

Yu, Shijie; Yang, Hailong; Wang, Rui; Luan, Zhongzhi; Qian, Depei

2017-01-01

As the energy consumption has been surging in an unsustainable way, it is important to understand the impact of existing architecture designs from energy efficiency perspective, which is especially valuable for High Performance Computing (HPC) and datacenter environment hosting tens of thousands of servers. One obstacle hindering the advance of comprehensive evaluation on energy efficiency is the deficient power measuring approach. Most of the energy study relies on either external power meters or power models, both of these two methods contain intrinsic drawbacks in their practical adoption and measuring accuracy. Fortunately, the advent of Intel Running Average Power Limit (RAPL) interfaces has promoted the power measurement ability into next level, with higher accuracy and finer time resolution. Therefore, we argue it is the exact time to conduct an in-depth evaluation of the existing architecture designs to understand their impact on system energy efficiency. In this paper, we leverage representative benchmark suites including serial and parallel workloads from diverse domains to evaluate the architecture features such as Non Uniform Memory Access (NUMA), Simultaneous Multithreading (SMT) and Turbo Boost. The energy is tracked at subcomponent level such as Central Processing Unit (CPU) cores, uncore components and Dynamic Random-Access Memory (DRAM) through exploiting the power measurement ability exposed by RAPL. The experiments reveal non-intuitive results: 1) the mismatch between local compute and remote memory node caused by NUMA effect not only generates dramatic power and energy surge but also deteriorates the energy efficiency significantly; 2) for multithreaded application such as the Princeton Application Repository for Shared-Memory Computers (PARSEC), most of the workloads benefit a notable increase of energy efficiency using SMT, with more than 40% decline in average power consumption; 3) Turbo Boost is effective to accelerate the workload execution and further preserve the energy, however it may not be applicable on system with tight power budget.

Technical support documentation for the Automated Residential Energy Standard (ARES) in support of proposed interim energy conservation voluntary performance standards for new non-federal residential buildings: Volume 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The Automated Residential Energy Standard (ARES) program is designed to identify levels of thermal integrity (e.g., insulation levels, glazing layers, equipment efficiencies, etc.) that are cost effective for typical residential structures and to create a residential energy standard based on these levels. This document contains technical background the explains the data and the algorithms used by the program.

Rolling resistance and propulsion efficiency of manual and power-assisted wheelchairs.

PubMed

Pavlidou, Efthymia; Kloosterman, Marieke G M; Buurke, Jaap H; Rietman, Johan S; Janssen, Thomas W J

2015-11-01

Rolling resistance is one of the main forces resisting wheelchair propulsion and thus affecting stress exerted on the upper limbs. The present study investigates the differences in rolling resistance, propulsion efficiency and energy expenditure required by the user during power-assisted and manual propulsion. Different tire pressures (50%, 75%, 100%) and two different levels of motor assistance were tested. Drag force, energy expenditure and propulsion efficiency were measured in 10 able-bodied individuals under different experimental settings on a treadmill. Results showed that drag force levels were significantly higher in the 50%, compared to the 75% and 100% inflation conditions. In terms of wheelchair type, the manual wheelchair displayed significantly lower drag force values than the power-assisted one. The use of extra-power-assisted wheelchair appeared to be significantly superior to conventional power-assisted and manual wheelchairs concerning both propulsion efficiency and energy expenditure required by the user. Overall, the results of the study suggest that the use of power-assisted wheelchair was more efficient and required less energy input by the user, depending on the motor assistance provided. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Exciton shelves for charge and energy transport in third-generation quantum-dot devices

NASA Astrophysics Data System (ADS)

Goodman, Samuel; Singh, Vivek; Noh, Hyunwoo; Casamada, Josep; Chatterjee, Anushree; Cha, Jennifer; Nagpal, Prashant

2014-03-01

Quantum dots are semiconductor nanocrystallites with size-dependent quantum-confined energy levels. While they have been intensively investigated to utilize hot-carriers for photovoltaic applications, to bridge the mismatch between incident solar photons and finite bandgap of semiconductor photocells, efficient charge or exciton transport in quantum-dot films has proven challenging. Here we show development of new coupled conjugated molecular wires with ``exciton shelves'', or different energy levels, matched with the multiple energy levels of quantum dots. Using single nanoparticle and ensemble device measurements we show successful extraction and transport of both bandedge and high-energy charge carriers, and energy transport of excitons. We demonstrate using measurements of electronic density of states, that careful matching of energy states of quantum-dot with molecular wires is important, and any mismatch can generate midgap states leading to charge recombination and reduced efficiency. Therefore, these exciton-shelves and quantum dots can lead to development of next-generation photovoltaic and photodetection devices using simultaneous transport of bandedge and hot-carriers or energy transport of excitons in these nanostructured solution-processed films.

GLIDES – Efficient Energy Storage from ORNL

ScienceCinema

Momen, Ayyoub M.; Abu-Heiba, Ahmad; Odukomaiya, Wale; Akinina, Alla

2018-06-25

The research shown in this video features the GLIDES (Ground-Level Integrated Diverse Energy Storage) project, which has been under development at Oak Ridge National Laboratory (ORNL) since 2013. GLIDES can store energy via combined inputs of electricity and heat, and deliver dispatchable electricity. Supported by ORNL’s Laboratory Director’s Research and Development (LDRD) fund, this energy storage system is low-cost, and hybridizes compressed air and pumped-hydro approaches to allow for storage of intermittent renewable energy at high efficiency. A U.S. patent application for this novel energy storage concept has been submitted, and research findings suggest it has the potential to be a flexible, low-cost, scalable, high-efficiency option for energy storage, especially useful in residential and commercial buildings.

GLIDES – Efficient Energy Storage from ORNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Momen, Ayyoub M.; Abu-Heiba, Ahmad; Odukomaiya, Wale

2016-03-01

The research shown in this video features the GLIDES (Ground-Level Integrated Diverse Energy Storage) project, which has been under development at Oak Ridge National Laboratory (ORNL) since 2013. GLIDES can store energy via combined inputs of electricity and heat, and deliver dispatchable electricity. Supported by ORNL’s Laboratory Director’s Research and Development (LDRD) fund, this energy storage system is low-cost, and hybridizes compressed air and pumped-hydro approaches to allow for storage of intermittent renewable energy at high efficiency. A U.S. patent application for this novel energy storage concept has been submitted, and research findings suggest it has the potential to bemore » a flexible, low-cost, scalable, high-efficiency option for energy storage, especially useful in residential and commercial buildings.« less

Modeling Pumped Thermal Energy Storage with Waste Heat Harvesting

NASA Astrophysics Data System (ADS)

Abarr, Miles L. Lindsey

This work introduces a new concept for a utility scale combined energy storage and generation system. The proposed design utilizes a pumped thermal energy storage (PTES) system, which also utilizes waste heat leaving a natural gas peaker plant. This system creates a low cost utility-scale energy storage system by leveraging this dual-functionality. This dissertation first presents a review of previous work in PTES as well as the details of the proposed integrated bottoming and energy storage system. A time-domain system model was developed in Mathworks R2016a Simscape and Simulink software to analyze this system. Validation of both the fluid state model and the thermal energy storage model are provided. The experimental results showed the average error in cumulative fluid energy between simulation and measurement was +/- 0.3% per hour. Comparison to a Finite Element Analysis (FEA) model showed <1% error for bottoming mode heat transfer. The system model was used to conduct sensitivity analysis, baseline performance, and levelized cost of energy of a recently proposed Pumped Thermal Energy Storage and Bottoming System (Bot-PTES) that uses ammonia as the working fluid. This analysis focused on the effects of hot thermal storage utilization, system pressure, and evaporator/condenser size on the system performance. This work presents the estimated performance for a proposed baseline Bot-PTES. Results of this analysis showed that all selected parameters had significant effects on efficiency, with the evaporator/condenser size having the largest effect over the selected ranges. Results for the baseline case showed stand-alone energy storage efficiencies between 51 and 66% for varying power levels and charge states, and a stand-alone bottoming efficiency of 24%. The resulting efficiencies for this case were low compared to competing technologies; however, the dual-functionality of the Bot-PTES enables it to have higher capacity factor, leading to 91-197/MWh levelized cost of energy compared to 262-284/MWh for batteries and $172-254/MWh for Compressed Air Energy Storage.

Transportation Energy Futures Series. Potential for Energy Efficiency Improvement Beyond the Light-Duty-Vehicle Sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vyas, A. D.; Patel, D. M.; Bertram, K. M.

2013-02-01

Considerable research has focused on energy efficiency and fuel substitution options for light-duty vehicles, while much less attention has been given to medium- and heavy-duty trucks, buses, aircraft, marine vessels, trains, pipeline, and off-road equipment. This report brings together the salient findings from an extensive review of literature on future energy efficiency options for these non-light-duty modes. Projected activity increases to 2050 are combined with forecasts of overall fuel efficiency improvement potential to estimate the future total petroleum and greenhouse gas (GHG) emissions relative to current levels. This is one of a series of reports produced as a result ofmore » the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Transportation Energy Futures Series: Potential for Energy Efficiency Improvement Beyond the Light-Duty-Vehicle Sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vyas, A. D.; Patel, D. M.; Bertram, K. M.

2013-03-01

Considerable research has focused on energy efficiency and fuel substitution options for light-duty vehicles, while much less attention has been given to medium- and heavy-duty trucks, buses, aircraft, marine vessels, trains, pipeline, and off-road equipment. This report brings together the salient findings from an extensive review of literature on future energy efficiency options for these non-light-duty modes. Projected activity increases to 2050 are combined with forecasts of overall fuel efficiency improvement potential to estimate the future total petroleum and greenhouse gas (GHG) emissions relative to current levels. This is one of a series of reports produced as a result ofmore » the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Smart Manufacturing Technologies and Data Analytics for Improving Energy Efficiency in Industrial Energy Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nimbalkar, Sachin U.; Guo, Wei; Wenning, Thomas J.

Smart manufacturing and advanced data analytics can help the manufacturing sector unlock energy efficiency from the equipment level to the entire manufacturing facility and the whole supply chain. These technologies can make manufacturing industries more competitive, with intelligent communication systems, real-time energy savings, and increased energy productivity. Smart manufacturing can give all employees in an organization the actionable information they need, when they need it, so that each person can contribute to the optimal operation of the corporation through informed, data-driven decision making. This paper examines smart technologies and data analytics approaches for improving energy efficiency and reducing energy costsmore » in process-supporting energy systems. It dives into energy-saving improvement opportunities through smart manufacturing technologies and sophisticated data collection and analysis. The energy systems covered in this paper include those with motors and drives, fans, pumps, air compressors, steam, and process heating.« less

Efficient transformer for electromagnetic waves

DOEpatents

Miller, R.B.

A transformer structure for efficient transfer of electromagnetic energy from a transmission line to an unmatched load provides voltage multiplication and current division by a predetermined constant. Impedance levels are transformed by the square of that constant. The structure includes a wave splitter, connected to an input transmission device and to a plurality of output transmission devices. The output transmission devices are effectively connected in parallel to the input transmission device. The output transmission devices are effectively series connected to provide energy to a load. The transformer structure is particularly effective in increasing efficiency of energy transfer through an inverting convolute structure by capturing and transferring energy losses from the inverter to the load.

Saturation and energy-conversion efficiency of auroral kilometric radiation

NASA Technical Reports Server (NTRS)

Wu, C. S.; Tsai, S. T.; Xu, M. J.; Shen, J. W.

1981-01-01

A quasi-linear theory is used to study the saturation level of the auroral kilometric radiation. The investigation is based on the assumption that the emission is due to a cyclotron maser instability as suggested by Wu and Lee and Lee et al. The thermodynamic bound on the radiation energy is also estimated separately. The energy-conversion efficiency of the radiation process is discussed. The results are consistent with observations.

Ultralow-power electronics for biomedical applications.

PubMed

Chandrakasan, Anantha P; Verma, Naveen; Daly, Denis C

2008-01-01

The electronics of a general biomedical device consist of energy delivery, analog-to-digital conversion, signal processing, and communication subsystems. Each of these blocks must be designed for minimum energy consumption. Specific design techniques, such as aggressive voltage scaling, dynamic power-performance management, and energy-efficient signaling, must be employed to adhere to the stringent energy constraint. The constraint itself is set by the energy source, so energy harvesting holds tremendous promise toward enabling sophisticated systems without straining user lifestyle. Further, once harvested, efficient delivery of the low-energy levels, as well as robust operation in the aggressive low-power modes, requires careful understanding and treatment of the specific design limitations that dominate this realm. We outline the performance and power constraints of biomedical devices, and present circuit techniques to achieve complete systems operating down to power levels of microwatts. In all cases, approaches that leverage advanced technology trends are emphasized.

Synergistic effect of fluorination on molecular energy level modulation in highly efficient photovoltaic polymers.

PubMed

Zhang, Maojie; Guo, Xia; Zhang, Shaoqing; Hou, Jianhui

2014-02-01

The synergistic effect of fluorination on molecular energy level modulation is realized by introducing fluorine atoms onto both the donor and the acceptor moieties in a D-A polymer, and as a result, the polymer solar cell device based on the trifluorinated polymer, PBT-3F, shows a high efficiency of 8.6%, under illumination of AM 1.5G, 100 mW cm(-) (2) . © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The SEAD global efficiency medal competition: accelerating market transformation for efficient televisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ravi, Kavita; Bennich, Peter; Cockburn, John

2013-10-15

The Global Efficiency Medal competition, a cornerstone activity of the Super-efficient Equipment and Appliance Deployment (SEAD) Initiative, is an awards program that encourages the production and sale of super-efficient products. SEAD is a voluntary multinational government collaboration of the Clean Energy Ministerial (CEM). This winner-takes-all competition recognizes products with the best energy efficiency, guides early adopter purchasers towards the most efficient product choices and demonstrates the levels of energy efficiency achievable by commercially available and emerging technologies. The first Global Efficiency Medals were awarded to the most energy-efficient flat panel televisions; an iconic consumer purchase. SEAD Global Efficiency Medals weremore » awarded to televisions that have proven to be substantially more energy efficient than comparable models available at the time of the competition (applications closed in the end of May 2012). The award-winning TVs consume between 33 to 44 percent less energy per 2 unit of screen area than comparable LED-backlit LCD televisions sold in each regional market and 50 to 60 percent less energy than CCFL-backlit LCD TVs. Prior to the launch of this competition, SEAD conducted an unprecedented international round-robin test (RRT) to qualify TV test laboratories to support verification testing for SEAD awards. The RRT resulted in increased test laboratory capacity and expertise around the world and ensured that the test results from participating regional test laboratories could be compared in a fair and transparent fashion. This paper highlights a range of benefits resulting from this first SEAD awards competition and encourages further investigation of the awards concept as a means to promote energy efficiency in other equipment types.« less

A Metamaterial-Inspired Approach to RF Energy Harvesting

NASA Astrophysics Data System (ADS)

Fowler, Clayton; Zhou, Jiangfeng

2016-03-01

We demonstrate an RF energy harvesting rectenna design based on a metamaterial perfect absorber (MPA). With the embedded Schottky diodes, the rectenna converts captured RF energy to DC currents. The Fabry-Perot cavity resonance of the MPA greatly improves the amount of energy captured and hence improves the rectification efficiency. Furthermore, the FP resonance exhibits a high Q-factor and significantly increases the voltage across the Schottky diodes. This leads to a factor of 16 improvement of RF-DC conversion efficiency at ambient intensity level.

A Metamaterial-Inspired Approach to RF Energy Harvesting

NASA Astrophysics Data System (ADS)

Fowler, Clayton; Zhou, Jiangfeng

We demonstrate an RF energy harvesting rectenna design based on a metamaterial perfect absorber (MPA). With the embedded Schottky diodes, the rectenna converts captured RF energy to DC currents. The Fabry-Perot cavity resonance of the MPA greatly improves the amount of energy captured and hence improves the rectification efficiency. Furthermore, the FP resonance exhibits high Q-factor and significantly increases the voltage across the Schottky diodes. This leads to a factor of 16 improvement of RF-DC conversion efficiency at ambient intensity level.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, Kelly L.; Foster, Rebecca; McGowan, Terry

This article for a building trade magazine describes a national design competition for energy efficient lighting sponsored by the U.S. Department of Energy, the American Lighting Association, and the Consortium for Energy Efficiency, with winners announced at ALA's Annual Conference May 14, 2004, in Tucson. The Lighting for Tomorrow competition was the first national lighting fixture design competition focusing on energy-efficient residential lighting. The competition invited fixture manufacturers and designers to come up with beautiful, functional lighting fixtures that also happen to be energy efficient. Fixtures were required to use a ''dedicated'' energy-efficient light source, such as a pin-based fluorescentmore » lamp that cannot be replaced with a screw-in incandescent bulb. Fixtures also had to meet a minimum energy efficiency level that eliminated use of incandescent and halogen lamps, leaving the door open only to fluorescent sources and LEDs. More than 150 paper designs were submitted in the first phase of the competition, in 2003. Of those, 24 finalists were invited to submit working prototypes in 2004, and the winners were announced in May. The Grand Prize of $10,000 went to American Fluorescent of Waukegan, Illinois, for its ''Salem'' chandelier. Some winning fixtures are already available through Lowe's Home Improvement Centers.« less

A Framework to Survey the Energy Efficiency of Installed Motor Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, Prakash; Hasanbeigi, Ali; McKane, Aimee

2013-08-01

While motors are ubiquitous throughout the globe, there is insufficient data to properly assess their level of energy efficiency across regional boundaries. Furthermore, many of the existing data sets focus on motor efficiency and neglect the connected drive and system. Without a comprehensive survey of the installed motor system base, a baseline energy efficiency of a country or region’s motor systems cannot be developed. The lack of data impedes government agencies, utilities, manufacturers, distributers, and energy managers when identifying where to invest resources to capture potential energy savings, creating programs aimed at reducing electrical energy consumption, or quantifying the impactsmore » of such programs. This paper will outline a data collection framework for use when conducting a survey under a variety of execution models to characterize motor system energy efficiency within a country or region. The framework is intended to standardize the data collected ensuring consistency across independently conducted surveys. Consistency allows for the surveys to be leveraged against each other enabling comparisons to motor system energy efficiencies from other regions. In creating the framework, an analysis of various motor driven systems, including compressed air, pumping, and fan systems, was conducted and relevant parameters characterizing the efficiency of these systems were identified. A database using the framework will enable policymakers and industry to better assess the improvement potential of their installed motor system base particularly with respect to other regions, assisting in efforts to promote improvements to the energy efficiency of motor driven systems.« less

Development of a performance-based industrial energy efficiency indicator for corn refining plants.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, G. A.; Decision and Information Sciences; USEPA

2006-07-31

Organizations that implement strategic energy management programs have the potential to achieve sustained energy savings if the programs are carried out properly. A key opportunity for achieving energy savings that plant managers can take is to determine an appropriate level of energy performance by comparing their plant's performance with that of similar plants in the same industry. Manufacturing facilities can set energy efficiency targets by using performance-based indicators. The U.S. Environmental Protection Agency (EPA), through its ENERGY STAR{reg_sign} program, has been developing plant energy performance indicators (EPIs) to encourage a variety of U.S. industries to use energy more efficiently. Thismore » report describes work with the corn refining industry to provide a plant-level indicator of energy efficiency for facilities that produce a variety of products--including corn starch, corn oil, animal feed, corn sweeteners, and ethanol--for the paper, food, beverage, and other industries in the United States. Consideration is given to the role that performance-based indicators play in motivating change; the steps needed to develop indicators, including interacting with an industry to secure adequate data for an indicator; and the actual application and use of an indicator when complete. How indicators are employed in the EPA's efforts to encourage industries to voluntarily improve their use of energy is discussed as well. The report describes the data and statistical methods used to construct the EPI for corn refining plants. Individual equations are presented, as are the instructions for using them in an associated Excel spreadsheet.« less

Design and Implementation of RF Energy Harvesting System for Low-Power Electronic Devices

NASA Astrophysics Data System (ADS)

Uzun, Yunus

2016-08-01

Radio frequency (RF) energy harvester systems are a good alternative for energizing of low-power electronics devices. In this work, an RF energy harvester is presented to obtain energy from Global System for Mobile Communications (GSM) 900 MHz signals. The energy harvester, consisting of a two-stage Dickson voltage multiplier circuit and L-type impedance matching circuits, was designed, simulated, fabricated and tested experimentally in terms of its performance. Simulation and experimental works were carried out for various input power levels, load resistances and input frequencies. Both simulation and experimental works have been carried out for this frequency band. An efficiency of 45% is obtained from the system at 0 dBm input power level using the impedance matching circuit. This corresponds to the power of 450 μW and this value is sufficient for many low-power devices. The most important parameters affecting the efficiency of the RF energy harvester are the input power level, frequency band, impedance matching and voltage multiplier circuits, load resistance and the selection of diodes. RF energy harvester designs should be optimized in terms of these parameters.

An Efficient Method to Evaluate Intermolecular Interaction Energies in Large Systems Using Overlapping Multicenter ONIOM and the Fragment Molecular Orbital Method

PubMed Central

Asada, Naoya; Fedorov, Dmitri G.; Kitaura, Kazuo; Nakanishi, Isao; Merz, Kenneth M.

2012-01-01

We propose an approach based on the overlapping multicenter ONIOM to evaluate intermolecular interaction energies in large systems and demonstrate its accuracy on several representative systems in the complete basis set limit at the MP2 and CCSD(T) level of theory. In the application to the intermolecular interaction energy between insulin dimer and 4′-hydroxyacetanilide at the MP2/CBS level, we use the fragment molecular orbital method for the calculation of the entire complex assigned to the lowest layer in three-layer ONIOM. The developed method is shown to be efficient and accurate in the evaluation of the protein-ligand interaction energies. PMID:23050059

Energy level alignment at planar organic heterojunctions: influence of contact doping and molecular orientation.

PubMed

Opitz, Andreas

2017-04-05

Planar organic heterojunctions are widely used in photovoltaic cells, light-emitting diodes, and bilayer field-effect transistors. The energy level alignment in the devices plays an important role in obtaining the aspired gap arrangement. Additionally, the π-orbital overlap between the involved molecules defines e.g. the charge-separation efficiency in solar cells due to charge-transfer effects. To account for both aspects, direct/inverse photoemission spectroscopy and near edge x-ray absorption fine structure spectroscopy were used to determine the energy level landscape and the molecular orientation at prototypical planar organic heterojunctions. The combined experimental approach results in a comprehensive model for the electronic and morphological characteristics of the interface between the two investigated molecular semiconductors. Following an introduction on heterojunctions used in devices and on energy levels of organic materials, the energy level alignment of planar organic heterojunctions will be discussed. The observed energy landscape is always determined by the individual arrangement between the energy levels of the molecules and the work function of the electrode. This might result in contact doping due to Fermi level pinning at the electrode for donor/acceptor heterojunctions, which also improves the solar cell efficiency. This pinning behaviour can be observed across an unpinned interlayer and results in charge accumulation at the donor/acceptor interface, depending on the transport levels of the respective organic semiconductors. Moreover, molecular orientation will affect the energy levels because of the anisotropy in ionisation energy and electron affinity and is influenced by the structural compatibility of the involved molecules at the heterojunction. High structural compatibility leads to π-orbital stacking between different molecules at a heterojunction, which is of additional interest for photovoltaic active interfaces and for ground-state charge-transfer.

Study on Enhanceing Mechanisim and Policy on Energy Efficiency of Electrical Motor System in China

NASA Astrophysics Data System (ADS)

Liu, Ren; Zhao, Yuejin; Liu, Meng; Chen, Lili; Yang, Ming

2017-12-01

Motor is a kind of terminal energy-consumption equipment with the maximum power consumption in China every year; compared with international advanced level, the technical innovation of motor equipment, speed regulating system, drive system and automatic intelligent control technique in China still lag behind relatively; the standard technical service support system of motor system is not complete, the energy conserving transformation mode needs to be innovated, and the market development mechanism of motor industry is not perfect, etc. This paper analyzes the promotion mechanism and policy on energy efficiency of the motor system in China in recent years, studies the demonstration cases of successful promotion of high-efficiency motor, standard labeling, financial finance and tax policy, and puts forward suggestions on promotion of high-efficiency motor in China.

Residential End Uses: Historical Efficiency Data and Incremental Installed Costs for Efficiency Upgrades

EIA Publications

2017-01-01

The residential sector comprises equipment consuming various fuels and providing different end-use services. When replacing equipment, consumers may choose to purchase equipment that meets minimum federal equipment efficiency standards, or they may opt for higher-efficiency equipment, such as equipment that meets or exceeds ENERGY STAR® specifications. Consumers may also choose to purchase or retrofit different types of equipment, which may require additional costs (e.g., for ducts, exhaust vents, natural gas lines, or electrical connections) to install. The stock mix of equipment types, efficiency levels, and fuels consumed directly affects total residential sector energy consumption.

Blinking fluorescence of single donor-acceptor pairs: important role of "dark'' states in resonance energy transfer via singlet levels.

PubMed

Osad'ko, I S; Shchukina, A L

2012-06-01

The influence of triplet levels on Förster resonance energy transfer via singlet levels in donor-acceptor (D-A) pairs is studied. Four types of D-A pair are considered: (i) two-level donor and two-level acceptor, (ii) three-level donor and two-level acceptor, (iii) two-level donor and three-level acceptor, and (iv) three-level donor and three-level acceptor. If singlet-triplet transitions in a three-level acceptor molecule are ineffective, the energy transfer efficiency E=I_{A}/(I_{A}+I_{D}), where I_{D} and I_{A} are the average intensities of donor and acceptor fluorescence, can be described by the simple theoretical equation E(F)=FT_{D}/(1+FT_{D}). Here F is the rate of energy transfer, and T_{D} is the donor fluorescence lifetime. In accordance with the last equation, 100% of the donor electronic energy can be transferred to an acceptor molecule at FT_{D}≫1. However, if singlet-triplet transitions in a three-level acceptor molecule are effective, the energy transfer efficiency is described by another theoretical equation, E(F)=F[over ¯](F)T_{D}/[1+F[over ¯](F)T_{D}]. Here F[over ¯](F) is a function of F depending on singlet-triplet transitions in both donor and acceptor molecules. Expressions for the functions F[over ¯](F) are derived. In this case the energy transfer efficiency will be far from 100% even at FT_{D}≫1. The character of the intensity fluctuations of donor and acceptor fluorescence indicates which of the two equations for E(F) should be used to find the value of the rate F. Therefore, random time instants of photon emission in both donor and acceptor fluorescence are calculated by the Monte Carlo method for all four types of D-A pair. Theoretical expressions for start-stop correlators (waiting time distributions) in donor and acceptor fluorescence are derived. The probabilities w_{N}^{D}(t) and w_{N}^{A}(t) of finding N photons of donor and acceptor fluorescence in the time interval t are calculated for various values of the energy transfer rate F and for all four types of D-A pair. Comparison of the calculated D and A fluorescence trajectories with those measured by Weiss and co-workers proves the important role of triplet levels in energy transfer via singlet levels.

Efficient light emission from inorganic and organic semiconductor hybrid structures by energy-level tuning

PubMed Central

Schlesinger, R.; Bianchi, F.; Blumstengel, S.; Christodoulou, C.; Ovsyannikov, R.; Kobin, B.; Moudgil, K.; Barlow, S.; Hecht, S.; Marder, S.R.; Henneberger, F.; Koch, N.

2015-01-01

The fundamental limits of inorganic semiconductors for light emitting applications, such as holographic displays, biomedical imaging and ultrafast data processing and communication, might be overcome by hybridization with their organic counterparts, which feature enhanced frequency response and colour range. Innovative hybrid inorganic/organic structures exploit efficient electrical injection and high excitation density of inorganic semiconductors and subsequent energy transfer to the organic semiconductor, provided that the radiative emission yield is high. An inherent obstacle to that end is the unfavourable energy level offset at hybrid inorganic/organic structures, which rather facilitates charge transfer that quenches light emission. Here, we introduce a technologically relevant method to optimize the hybrid structure's energy levels, here comprising ZnO and a tailored ladder-type oligophenylene. The ZnO work function is substantially lowered with an organometallic donor monolayer, aligning the frontier levels of the inorganic and organic semiconductors. This increases the hybrid structure's radiative emission yield sevenfold, validating the relevance of our approach. PMID:25872919

Efficient light emission from inorganic and organic semiconductor hybrid structures by energy-level tuning.

PubMed

Schlesinger, R; Bianchi, F; Blumstengel, S; Christodoulou, C; Ovsyannikov, R; Kobin, B; Moudgil, K; Barlow, S; Hecht, S; Marder, S R; Henneberger, F; Koch, N

2015-04-15

The fundamental limits of inorganic semiconductors for light emitting applications, such as holographic displays, biomedical imaging and ultrafast data processing and communication, might be overcome by hybridization with their organic counterparts, which feature enhanced frequency response and colour range. Innovative hybrid inorganic/organic structures exploit efficient electrical injection and high excitation density of inorganic semiconductors and subsequent energy transfer to the organic semiconductor, provided that the radiative emission yield is high. An inherent obstacle to that end is the unfavourable energy level offset at hybrid inorganic/organic structures, which rather facilitates charge transfer that quenches light emission. Here, we introduce a technologically relevant method to optimize the hybrid structure's energy levels, here comprising ZnO and a tailored ladder-type oligophenylene. The ZnO work function is substantially lowered with an organometallic donor monolayer, aligning the frontier levels of the inorganic and organic semiconductors. This increases the hybrid structure's radiative emission yield sevenfold, validating the relevance of our approach.

Energy-efficient sensing in wireless sensor networks using compressed sensing.

PubMed

Razzaque, Mohammad Abdur; Dobson, Simon

2014-02-12

Sensing of the application environment is the main purpose of a wireless sensor network. Most existing energy management strategies and compression techniques assume that the sensing operation consumes significantly less energy than radio transmission and reception. This assumption does not hold in a number of practical applications. Sensing energy consumption in these applications may be comparable to, or even greater than, that of the radio. In this work, we support this claim by a quantitative analysis of the main operational energy costs of popular sensors, radios and sensor motes. In light of the importance of sensing level energy costs, especially for power hungry sensors, we consider compressed sensing and distributed compressed sensing as potential approaches to provide energy efficient sensing in wireless sensor networks. Numerical experiments investigating the effectiveness of compressed sensing and distributed compressed sensing using real datasets show their potential for efficient utilization of sensing and overall energy costs in wireless sensor networks. It is shown that, for some applications, compressed sensing and distributed compressed sensing can provide greater energy efficiency than transform coding and model-based adaptive sensing in wireless sensor networks.

Retrofitting a 1960s Split-Level, Cold-Climate Home

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puttagunta, Srikanth

2015-07-13

National programs such as Home Performance with ENERGY STAR® and numerous other utility air-sealing programs have made homeowners aware of the benefits of energy-efficiency retrofits. Yet these programs tend to focus only on the low-hanging fruit: they recommend air sealing the thermal envelope and ductwork where accessible, switching to efficient lighting and low-flow fixtures, and improving the efficiency of mechanical systems (though insufficient funds or lack of knowledge to implement these improvements commonly prevent the implementation of these higher cost upgrades). At the other end of the spectrum, various utilities across the country are encouraging deep energy retrofit programs. Althoughmore » deep energy retrofits typically seek 50% energy savings, they are often quite costly and are most applicable to gut-rehab projects. A significant potential for lowering energy use in existing homes lies between the lowhanging fruit and deep energy retrofit approaches—retrofits that save approximately 30% in energy compared to the pre-retrofit conditions. The energy-efficiency measures need to be nonintrusive so the retrofit projects can be accomplished in occupied homes.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mittal, Sparsh; Zhang, Zhao

With each CMOS technology generation, leakage energy consumption has been dramatically increasing and hence, managing leakage power consumption of large last-level caches (LLCs) has become a critical issue in modern processor design. In this paper, we present EnCache, a novel software-based technique which uses dynamic profiling-based cache reconfiguration for saving cache leakage energy. EnCache uses a simple hardware component called profiling cache, which dynamically predicts energy efficiency of an application for 32 possible cache configurations. Using these estimates, system software reconfigures the cache to the most energy efficient configuration. EnCache uses dynamic cache reconfiguration and hence, it does not requiremore » offline profiling or tuning the parameter for each application. Furthermore, EnCache optimizes directly for the overall memory subsystem (LLC and main memory) energy efficiency instead of the LLC energy efficiency alone. The experiments performed with an x86-64 simulator and workloads from SPEC2006 suite confirm that EnCache provides larger energy saving than a conventional energy saving scheme. For single core and dual-core system configurations, the average savings in memory subsystem energy over a shared baseline configuration are 30.0% and 27.3%, respectively.« less

NET-ZERO ENERGY BUILDING OPERATOR TRAINING PROGRAM (NZEBOT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brizendine, Anthony; Byars, Nan; Sleiti, Ahmad

2012-12-31

The primary objective of the Net-Zero Energy Building Operator Training Program (NZEBOT) was to develop certificate level training programs for commercial building owners, managers and operators, principally in the areas of energy / sustainability management. The expected outcome of the project was a multi-faceted mechanism for developing the skill-based competency of building operators, owners, architects/engineers, construction professionals, tenants, brokers and other interested groups in energy efficient building technologies and best practices. The training program draws heavily on DOE supported and developed materials available in the existing literature, as well as existing, modified, and newly developed curricula from the Department ofmore » Engineering Technology & Construction Management (ETCM) at the University of North Carolina at Charlotte (UNC-Charlotte). The project goal is to develop a certificate level training curriculum for commercial energy and sustainability managers and building operators that: 1) Increases the skill-based competency of building professionals in energy efficient building technologies and best practices, and 2) Increases the workforce pool of expertise in energy management and conservation techniques. The curriculum developed in this project can subsequently be used to establish a sustainable energy training program that can contribute to the creation of new “green” job opportunities in North Carolina and throughout the Southeast region, and workforce training that leads to overall reductions in commercial building energy consumption. Three energy training / education programs were developed to achieve the stated goal, namely: 1. Building Energy/Sustainability Management (BESM) Certificate Program for Building Managers and Operators (40 hours); 2. Energy Efficient Building Technologies (EEBT) Certificate Program (16 hours); and 3. Energy Efficent Buildings (EEB) Seminar (4 hours). Training Program 1 incorporates the following topics in the primary five-day Building Energy/Sustainability Management Certificate program in five training modules, namely: 1) Strategic Planning, 2) Sustainability Audits, 3) Information Analysis, 4) Energy Efficiency, and 5) Communication. Training Program 2 addresses the following technical topics in the two-day Building Technologies workshop: 1) Energy Efficient Building Materials, 2) Green Roofing Systems, 3) Energy Efficient Lighting Systems, 4) Alternative Power Systems for Buildings, 5) Innovative Building Systems, and 6) Application of Building Performance Simulation Software. Program 3 is a seminar which provides an overview of elements of programs 1 and 2 in a seminar style presentation designed for the general public to raise overall public awareness of energy and sustainability topics.« less

Radon safety in terms of energy efficiency classification of buildings

NASA Astrophysics Data System (ADS)

Vasilyev, A.; Yarmoshenko, I.; Zhukovsky, M.

2017-06-01

According to the results of survey in Ekaterinburg, Russia, indoor radon concentrations above city average level have been found in each of the studied buildings with high energy efficiency class. Measures to increase energy efficiency were confirmed to decrease the air exchange rate and accumulation of high radon concentrations indoors. Despite of recommendations to use mechanical ventilation with heat recovery as the main scenario for reducing elevated radon concentrations in energy-efficient buildings, the use of such systems did not show an obvious advantage. In real situation, mechanical ventilation system is not used properly both in the automatic and manual mode, which does not give an obvious advantage over natural ventilation in the climate of the Middle Urals in Ekaterinburg. Significant number of buildings with a high class of energy efficiency and built using modern space-planning decisions contributes to an increase in the average radon concentration. Such situation contradicts to “as low as reasonable achievable” principle of the radiation protection.

Energy Efficient Image/Video Data Transmission on Commercial Multi-Core Processors

PubMed Central

Lee, Sungju; Kim, Heegon; Chung, Yongwha; Park, Daihee

2012-01-01

In transmitting image/video data over Video Sensor Networks (VSNs), energy consumption must be minimized while maintaining high image/video quality. Although image/video compression is well known for its efficiency and usefulness in VSNs, the excessive costs associated with encoding computation and complexity still hinder its adoption for practical use. However, it is anticipated that high-performance handheld multi-core devices will be used as VSN processing nodes in the near future. In this paper, we propose a way to improve the energy efficiency of image and video compression with multi-core processors while maintaining the image/video quality. We improve the compression efficiency at the algorithmic level or derive the optimal parameters for the combination of a machine and compression based on the tradeoff between the energy consumption and the image/video quality. Based on experimental results, we confirm that the proposed approach can improve the energy efficiency of the straightforward approach by a factor of 2∼5 without compromising image/video quality. PMID:23202181

Polymer solar cells with enhanced open-circuit voltage and efficiency

NASA Astrophysics Data System (ADS)

Chen, Hsiang-Yu; Hou, Jianhui; Zhang, Shaoqing; Liang, Yongye; Yang, Guanwen; Yang, Yang; Yu, Luping; Wu, Yue; Li, Gang

2009-11-01

Following the development of the bulk heterojunction structure, recent years have seen a dramatic improvement in the efficiency of polymer solar cells. Maximizing the open-circuit voltage in a low-bandgap polymer is one of the critical factors towards enabling high-efficiency solar cells. Study of the relation between open-circuit voltage and the energy levels of the donor/acceptor in bulk heterojunction polymer solar cells has stimulated interest in modifying the open-circuit voltage by tuning the energy levels of polymers. Here, we show that the open-circuit voltage of polymer solar cells constructed based on the structure of a low-bandgap polymer, PBDTTT, can be tuned, step by step, using different functional groups, to achieve values as high as 0.76 V. This increased open-circuit voltage combined with a high short-circuit current density results in a polymer solar cell with a power conversion efficiency as high as 6.77%, as certified by the National Renewable Energy Laboratory.

Efficient Solar Energy Harvesting and Storage through a Robust Photocatalyst Driving Reversible Redox Reactions.

PubMed

Zhou, Yangen; Zhang, Shun; Ding, Yu; Zhang, Leyuan; Zhang, Changkun; Zhang, Xiaohong; Zhao, Yu; Yu, Guihua

2018-06-14

Simultaneous solar energy conversion and storage is receiving increasing interest for better utilization of the abundant yet intermittently available sunlight. Photoelectrodes driving nonspontaneous reversible redox reactions in solar-powered redox cells (SPRCs), which can deliver energy via the corresponding reverse reactions, present a cost-effective and promising approach for direct solar energy harvesting and storage. However, the lack of photoelectrodes having both high conversion efficiency and high durability becomes a bottleneck that hampers practical applications of SPRCs. Here, it is shown that a WO 3 -decorated BiVO 4 photoanode, without the need of extra electrocatalysts, can enable a single-photocatalyst-driven SPRC with a solar-to-output energy conversion efficiency as high as 1.25%. This SPRC presents stable performance over 20 solar energy storage/delivery cycles. The high efficiency and stability are attributed to the rapid redox reactions, the well-matched energy level, and the efficient light harvesting and charge separation of the prepared BiVO 4 . This demonstrated device system represents a potential alternative toward the development of low-cost, durable, and easy-to-implement solar energy technologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

NREL: International Activities - Bilateral Partnerships

Science.gov Websites

development and use of renewable energy and energy efficiency technologies: Algeria Angola Argentina Australia sufficiently accurate information for national-level strategic energy planning. China NREL manages renewable energy cooperation with China under the U.S.-China Renewable Energy Partnership program. This program was

Energy efficiency, renewable energy and sustainable development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ervin, C.A.

1994-12-31

The Office of Energy Efficiency and Renewable Energy (EE) is part of the U.S. Department of Energy that is specifically charged with encouraging the more efficient use of energy resources, and the use of renewable energy resources - such as solar power, wind power, biomass energy and geothermal energy. In the past several years, EE has increased its emphasis on technology deployment through partnerships with states, local governments and private companies. Partnerships move new discoveries more quickly into the marketplace, where they can create jobs, prevent pollution, save resources, and produce many other benefits. The author then emphasizes the importancemore » of this effort in a number of different sections of the paper: energy consumption pervades everything we do; U.S. energy imports are rising to record levels; transportation energy demand is increasing; U.S. energy use is increasing; population growth increases world energy demand; total costs of energy consumption aren`t always counted; world energy markets offer incredible potential; cost of renewables is decreasing; clean energy is essential to sustainable development; sustainable energy policy; sustainable energy initiatives: utilities, buildings, and transportation.« less

Experimental and Theoretical Investigation of the Function of 4- tert-Butyl Pyridine for Interface Energy Level Adjustment in Efficient Solid-State Dye-Sensitized Solar Cells.

PubMed

Yang, Lei; Lindblad, Rebecka; Gabrielsson, Erik; Boschloo, Gerrit; Rensmo, Håkan; Sun, Licheng; Hagfeldt, Anders; Edvinsson, Tomas; Johansson, Erik M J

2018-04-11

4- tert-Butylpyridine ( t-BP) is commonly used in solid state dye-sensitized solar cells (ssDSSCs) to increase the photovoltaic performance. In this report, the mechanism how t-BP functions as a favorable additive is investigated comprehensively. ssDSSCs were prepared with different concentrations of t-BP, and a clear increase in efficiency was observed up to a maximum concentration and for higher concentrations the efficiency thereafter decreases. The energy level alignment in the complete devices was measured using hard X-ray photoelectron spectroscopy (HAXPES). The results show that the energy levels of titanium dioxide are shifted further away from the energy levels of spiro-OMeTAD as the t-BP concentration is increased. This explains the higher photovoltage obtained in the devices with higher t-BP concentration. In addition, the electron lifetime was measured for the devices and the electron lifetime was increased when adding t-BP, which can be explained by the recombination blocking effect at the surface of TiO 2 . The results from the HAXPES measurements agree with those obtained from density functional theory calculations and give an understanding of the mechanism for the improvement, which is an important step for the future development of solar cells including t-BP.

Fluorescence properties and energy transfer study of Er3+/Nd3+ doped fluorophosphate glass pumped at 800 and 980 nm for mid-infrared laser applications

NASA Astrophysics Data System (ADS)

Tian, Ying; Xu, Rongrong; Hu, Lili; Zhang, Junjie

2012-04-01

The fluorescence properties of 2.7 μm emission as well as near infrared emissions in Er3+/Nd3+ doped fluorophosphate glasses are investigated under 800 and 980 nm excitation. The fluorescence dynamics and energy transfer processes between Er and Nd ions in different pumping schemes are reported. Three Judd-Ofelt intensity parameters, energy transfer microparameters, and efficiency have been determined using the Judd-Ofelt and Förster-Dexter theories. The calculated energy transfer efficiency of the Er3+:4I13/2 level to the Nd3+:4I15/2 level is as high as 83.91%. The results indicate that Nd3+ may be an efficient sensitizer for Er3+ to obtain mid-infrared emission and the more suitable pumping scheme of 2.7 μm laser applications for Er3+/Nd3+ doped fluorophosphate glass is 980 nm excitation.

The Shifting Landscape of Ratepayer-Funded Energy Efficiency in the U.S.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbose, Galen L; Goldman, Charles; Schlegel, Jeff

Over the last two decades, utility ratepayer funding for energy efficiency programs - and the associated energy savings - has seen both booms and busts. Currently, about 35 states implement ratepayer-funded energy efficiency programs, with a total U.S. budget of $3.1 billion in 2008, approximately 80% of which is concentrated in just ten states (CEE 2008).2 However, a proliferation of new state-level policies enacted over the past several years suggests that the next decade may see a dramatic and sustained increase in overall funding levels, and a fundamental re-drawing of the energy efficiency map. These new state energy efficiency policiesmore » reflect a variety of concerns, including the increasing cost and siting challenges of building new generation and transmission, fuel cost and supply risks, and the potential cost of future carbon regulations. Within the past three years, for example, eleven states have adopted energy efficiency portfolio (or resource) standards (EEPS or EERS) that establish specific long-term savings targets that utilities are obligated to meet, and at least three other states are currently considering the same. A growing number of states have recently established laws requiring utilities to acquire all available cost-effective energy efficiency. Regulators in several Western states have also recently revised integrated resource planning (IRP) and demand-side management (DSM) planning rules to require more robust analysis of the resource potential and benefits of energy efficiency, which has resulted in increased savings targets for their energy efficiency portfolios (Hopper et al. 2008). Finally, regulators and utilities in many states are beginning to look more closely at regulatory incentive mechanisms to better align utility financial interests with improvements in customer energy efficiency. We examined energy efficiency policies on the books or in the pipeline in all 50 states, along with recent IRPs and DSM plans, and developed low, medium and high projections of future energy efficiency spending and savings. Depending on how aggressively and effectively states implement these policies, we estimate that spending on ratepayer-funded energy efficiency could increase from $3.1 billion in 2008 to more than $12 billion (nominal dollars) per year by 2020 in our high case, a growth rate in spending of about 12% per year. Annual electricity savings nationally could triple from an estimated 0.3% of retail electricity sales in 2008 to 0.9% of retail electricity sales in 2020. In the low and medium scenarios, ratepayer funding for electric and gas energy efficiency in the U.S. would increase to $5.4 and $7.5 billion, respectively, by 2020. What are the implications of such a scale-up of ratepayer-funded energy efficiency activity for national energy policy, such as a national EEPS or future carbon regulations? Can a ramp-up of this scale be achieved, and what practical constraints might slow these efforts? This paper addresses these questions by first providing an overview of recent trends in state policies pertaining to ratepayer-funded energy efficiency programs in the U.S. The paper then presents our set of projections of future spending and savings from such programs, highlighting key themes. Projected energy savings are compared to what might be required under a future national EEPS (or broader clean energy standard that includes energy efficiency), in order to gauge the potential incremental impact of such policies. In addition, the carbon emission reductions associated with our projection of energy savings from ratepayer-funded programs is compared to the total emission reductions that might be required under the American Clean Energy and Security Act of 2009 (aka, the Waxman-Markey bill), which was passed by the U.S. House of Representatives in June 2009 and would establish a cap on total greenhouse gas emission for many sectors of the U.S. economy. Last, the paper discusses some of the major obstacles and challenges that states and program administrators may face over the coming decade, as they seek to dramatically ramp-up ratepayer-funded energy efficiency program activity, as projected.« less

Sensitivity of Water-Energy Nexus to dam operation: A Water-Energy Productivity concept.

PubMed

Basheer, Mohammed; Elagib, Nadir Ahmed

2018-03-01

Understanding and modelling the complex nature of interlinkages between water and energy are essential for efficient use of the two resources. Hydropower storage dams represent an interesting example of the water-energy interdependencies since they are often multipurpose. The concept of Water-Energy Productivity (WEP), defined as the amount of energy produced per unit of water lost in the process, is introduced in this study to illustrate the relationship between energy generation and water losses by examining the sensitivity of the Water-Energy Nexus (WEN) to changing dam operation policy. This concept is demonstrated by developing a water allocation model of the White Nile in Sudan, including Jebel Aulia Dam (JAD), using a general river and reservoir simulation software called RiverWare. A number of 77 operation scenarios of JAD are examined for 30 hydrologic years (1980-2009), considering reducing the Full Supply Level (FSL) gradually from its current value to the minimum possible value, increasing the Minimum Operating Level (MOL) gradually to the maximum possible level, and operating the dam at a Constant Operating Level (COL). The results show that raising the operating level does not necessarily increase the WEP. In comparison to the current policy, the analysis shows that a maximum WEP of 32.6GWh/BCM (GWh/Billion Cubic Meters) would be reached by raising the MOL to 375masl (meters above sea level), resulting in an increase in average annual energy generation to 164.6GWh (+18.1%) at the expense of an annual water loss of 5.05BCM (+12.7%). Even though this operation policy results in a more efficient water use compared to the original operation policy, a basin-wide assessment that includes all hydropower storage dams in the Nile basin should be conducted to decide on where and how much energy should be generated. The present analysis and future examination of the multi-dimensions of the WEN in the context of dam operation are imperative to improve the decision making in the quest for efficient resource use and management. Copyright © 2017 Elsevier B.V. All rights reserved.

An impact assessment of sustainable technologies for the Chinese urban residential sector at provincial level

NASA Astrophysics Data System (ADS)

Xing, Rui; Hanaoka, Tatsuya; Kanamori, Yuko; Dai, Hancheng; Masui, Toshihiko

2015-06-01

Recently, energy use in the urban residential sector of China has drastically increased due to higher incomes and urbanization. The fossil fuels dominant energy supply has since worsened the air quality, especially in urban areas. In this study we estimate the future energy service demands in Chinese urban residential areas, and then use an AIM/Enduse model to evaluate the emission reduction potential of CO2, SO2, NOx and PM. Considering the climate diversity and its impact on household energy service demands, our analysis is down-scaled to the provincial-level. The results show that in most of the regions, penetration of efficient technologies will bring CO2 emission reductions of over 20% compared to the baseline by the year 2030. Deployment of energy efficient technologies also co-benefits GHG emission reduction. However, efficient technology selection appears to differ across provinces due to climatic variation and economic disparity. For instance, geothermal heating technology is effective for the cold Northern areas while biomass technology contributes to emission reduction the most in the warm Southern areas.

Smart Buildings and Demand Response

NASA Astrophysics Data System (ADS)

Kiliccote, Sila; Piette, Mary Ann; Ghatikar, Girish

2011-11-01

Advances in communications and control technology, the strengthening of the Internet, and the growing appreciation of the urgency to reduce demand side energy use are motivating the development of improvements in both energy efficiency and demand response (DR) systems in buildings. This paper provides a framework linking continuous energy management and continuous communications for automated demand response (Auto-DR) in various times scales. We provide a set of concepts for monitoring and controls linked to standards and procedures such as Open Automation Demand Response Communication Standards (OpenADR). Basic building energy science and control issues in this approach begin with key building components, systems, end-uses and whole building energy performance metrics. The paper presents a framework about when energy is used, levels of services by energy using systems, granularity of control, and speed of telemetry. DR, when defined as a discrete event, requires a different set of building service levels than daily operations. We provide examples of lessons from DR case studies and links to energy efficiency.

Personalized Energy Reduction Cyber-Physical System (PERCS): A gamified end-user platform for energy efficiency and demand response.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sintov, Nicole; Orosz, Michael; Schultz, P. Wesley

2015-01-01

The mission of the Personalized Energy Reduction Cyber-physical System (PERCS) is to create new possibilities for improving building operating efficiency, enhancing grid reliability, avoiding costly power interruptions, and mitigating greenhouse gas emissions. PERCS proposes to achieve these outcomes by engaging building occupants as partners in a user-centered smart service platform. Using a non-intrusive load monitoring approach, PERCS uses a single sensing point in each home to capture smart electric meter data in real time. The household energy signal is disaggregated into individual load signatures of common appliances (e.g., air conditioners), yielding near real-time appliance-level energy information. Users interact with PERCSmore » via a mobile phone platform that provides household- and appliance-level energy feedback, tailored recommendations, and a competitive game tied to energy use and behavioral changes. PERCS challenges traditional energy management approaches by directly engaging occupant as key elements in a technological system.« less

Selection of bi-level image compression method for reduction of communication energy in wireless visual sensor networks

NASA Astrophysics Data System (ADS)

Khursheed, Khursheed; Imran, Muhammad; Ahmad, Naeem; O'Nils, Mattias

2012-06-01

Wireless Visual Sensor Network (WVSN) is an emerging field which combines image sensor, on board computation unit, communication component and energy source. Compared to the traditional wireless sensor network, which operates on one dimensional data, such as temperature, pressure values etc., WVSN operates on two dimensional data (images) which requires higher processing power and communication bandwidth. Normally, WVSNs are deployed in areas where installation of wired solutions is not feasible. The energy budget in these networks is limited to the batteries, because of the wireless nature of the application. Due to the limited availability of energy, the processing at Visual Sensor Nodes (VSN) and communication from VSN to server should consume as low energy as possible. Transmission of raw images wirelessly consumes a lot of energy and requires higher communication bandwidth. Data compression methods reduce data efficiently and hence will be effective in reducing communication cost in WVSN. In this paper, we have compared the compression efficiency and complexity of six well known bi-level image compression methods. The focus is to determine the compression algorithms which can efficiently compress bi-level images and their computational complexity is suitable for computational platform used in WVSNs. These results can be used as a road map for selection of compression methods for different sets of constraints in WVSN.

The assessment of global thermo-energy performances of existing district heating systems optimized by harnessing renewable energy sources

NASA Astrophysics Data System (ADS)

Şoimoşan, Teodora M.; Danku, Gelu; Felseghi, Raluca A.

2017-12-01

Within the thermo-energy optimization process of an existing heating system, the increase of the system's energy efficiency and speeding-up the transition to green energy use are pursued. The concept of multi-energy district heating system, with high harnessing levels of the renewable energy sources (RES) in order to produce heat, is expected to be the key-element in the future urban energy infrastructure, due to the important role it can have in the strategies of optimizing and decarbonizing the existing district heating systems. The issues that arise are related to the efficient integration of different technologies of harnessing renewable energy sources in the energy mix and to the increase of the participation levels of RES, respectively. For the holistic modeling of the district heating system, the concept of the energy hub was used, where the synergy of different primary forms of entered energy provides the system a high degree energy security and flexibility in operation. The optimization of energy flows within the energy hub allows the optimization of the thermo-energy district system in order to approach the dual concept of smart city & smart energy.

City Reach Code Technical Support Document

DOE Office of Scientific and Technical Information (OSTI.GOV)

Athalye, Rahul A.; Chen, Yan; Zhang, Jian

This report describes and analyzes a set of energy efficiency measures that will save 20% energy over ASHRAE Standard 90.1-2013. The measures will be used to formulate a Reach Code for cities aiming to go beyond national model energy codes. A coalition of U.S. cities together with other stakeholders wanted to facilitate the development of voluntary guidelines and standards that can be implemented in stages at the city level to improve building energy efficiency. The coalition's efforts are being supported by the U.S. Department of Energy via Pacific Northwest National Laboratory (PNNL) and in collaboration with the New Buildings Institute.

Product lifetime, energy efficiency and climate change: A case study of air conditioners in Japan.

PubMed

Nishijima, Daisuke

2016-10-01

This study proposed a modelling technique for estimating life-cycle CO2 emissions of durable goods by considering changes in product lifetime and energy efficiency. The stock and flow of durable goods was modelled by Weibull lifetime distributions and the trend in annual energy efficiency (i.e., annual electricity consumption) of an "average" durable good was formulated as a reverse logistic curve including a technologically critical value (i.e., limit energy efficiency) with respect to time. I found that when the average product lifetime is reduced, there is a trade-off between the reduction in emissions during product use (use phase), due to the additional purchases of new, more energy-efficient air conditioners, and the increase in emissions arising from the additional production of new air conditioners stimulated by the reduction of the average product lifetime. A scenario analysis focused on residential air conditioners in Japan during 1972-2013 showed that for a reduction of average lifetime of 1 year, if the air conditioner energy efficiency limit can be improved by 1.4% from the estimated current efficiency level, then CO2 emissions can be reduced by approximately the same amount as for an extension of average product lifetime of 1 year. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design of high efficiency and energy saving aeration device for aquaculture

NASA Astrophysics Data System (ADS)

Liu, Sibo

2017-03-01

Energy efficient aeration device for aquaculture, in line with "by more than a generation, dynamic aeration" train of thought for technical design and improvement. Removable aeration terminal as the core, multi-level water to improve the method, the mobile fading pore aeration, intelligent mobile and open and close as the main function, aimed at solving the existing pond aeration efficiency, low energy consumption is high, the function of a single problem. From energy saving, efficiency, biological bacteria on the three directions, the aquaculture industry of energy conservation and emissions reduction. Device of the main advantages are: 1, original mobile fading aerator on the one hand, to expand the scope of work, playing a micro porous aeration of dissolved oxygen with high efficiency and to achieve "by more than a generation", on the other hand, through the sports equipment, stir the mixture of water, the water surface of photosynthesis of plants rich in dissolved oxygen input parts of the tank, compared to the stillness of the aerator can be more fully dissolved oxygen.2, through the opening of the pressure sensor indirect control device, can make the equipment timely and stop operation, convenient in use at the same time avoid the waste of energy.3, the biofilm suspension in aeration terminal, can be accomplished by nitration of microbial multi-level water improvement, still can make biofilm increase rate of netting in the movement process, the biological and mechanical aerobic promote each other, improve the efficiency of both. In addition, the device has small power consumption, low cost of characteristics. And have a certain degree of technical barriers, have their own intellectual property rights, and high degree of product market demand, easily accepted by customers, has a very high popularization value.

An Energy Efficient Cooperative Hierarchical MIMO Clustering Scheme for Wireless Sensor Networks

PubMed Central

Nasim, Mehwish; Qaisar, Saad; Lee, Sungyoung

2012-01-01

In this work, we present an energy efficient hierarchical cooperative clustering scheme for wireless sensor networks. Communication cost is a crucial factor in depleting the energy of sensor nodes. In the proposed scheme, nodes cooperate to form clusters at each level of network hierarchy ensuring maximal coverage and minimal energy expenditure with relatively uniform distribution of load within the network. Performance is enhanced by cooperative multiple-input multiple-output (MIMO) communication ensuring energy efficiency for WSN deployments over large geographical areas. We test our scheme using TOSSIM and compare the proposed scheme with cooperative multiple-input multiple-output (CMIMO) clustering scheme and traditional multihop Single-Input-Single-Output (SISO) routing approach. Performance is evaluated on the basis of number of clusters, number of hops, energy consumption and network lifetime. Experimental results show significant energy conservation and increase in network lifetime as compared to existing schemes. PMID:22368459

Exergy Based Analysis for the Environmental Control and Life Support Systems of the International Space Station

NASA Technical Reports Server (NTRS)

Clem, Kirk A.; Nelson, George J.; Mesmer, Bryan L.; Watson, Michael D.; Perry, Jay L.

2016-01-01

When optimizing the performance of complex systems, a logical area for concern is improving the efficiency of useful energy. The energy available for a system to perform work is defined as a system's energy content. Interactions between a system's subsystems and the surrounding environment can be accounted for by understanding various subsystem energy efficiencies. Energy balance of reactants and products, and enthalpies and entropies, can be used to represent a chemical process. Heat transfer energy represents heat loads, and flow energy represents system flows and filters. These elements allow for a system level energy balance. The energy balance equations are developed for the subsystems of the Environmental Control and Life Support (ECLS) system aboard the International Space Station (ISS). The use of these equations with system information would allow for the calculation of the energy efficiency of the system, enabling comparisons of the ISS ECLS system to other systems as well as allows for an integrated systems analysis for system optimization.

Efficient globally optimal segmentation of cells in fluorescence microscopy images using level sets and convex energy functionals.

PubMed

Bergeest, Jan-Philip; Rohr, Karl

2012-10-01

In high-throughput applications, accurate and efficient segmentation of cells in fluorescence microscopy images is of central importance for the quantification of protein expression and the understanding of cell function. We propose an approach for segmenting cell nuclei which is based on active contours using level sets and convex energy functionals. Compared to previous work, our approach determines the global solution. Thus, the approach does not suffer from local minima and the segmentation result does not depend on the initialization. We consider three different well-known energy functionals for active contour-based segmentation and introduce convex formulations of these functionals. We also suggest a numeric approach for efficiently computing the solution. The performance of our approach has been evaluated using fluorescence microscopy images from different experiments comprising different cell types. We have also performed a quantitative comparison with previous segmentation approaches. Copyright © 2012 Elsevier B.V. All rights reserved.

A Comprehensive Study on Energy Efficiency and Performance of Flash-based SSD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Seon-Yeon; Kim, Youngjae; Urgaonkar, Bhuvan

2011-01-01

Use of flash memory as a storage medium is becoming popular in diverse computing environments. However, because of differences in interface, flash memory requires a hard-disk-emulation layer, called FTL (flash translation layer). Although the FTL enables flash memory storages to replace conventional hard disks, it induces significant computational and space overhead. Despite the low power consumption of flash memory, this overhead leads to significant power consumption in an overall storage system. In this paper, we analyze the characteristics of flash-based storage devices from the viewpoint of power consumption and energy efficiency by using various methodologies. First, we utilize simulation tomore » investigate the interior operation of flash-based storage of flash-based storages. Subsequently, we measure the performance and energy efficiency of commodity flash-based SSDs by using microbenchmarks to identify the block-device level characteristics and macrobenchmarks to reveal their filesystem level characteristics.« less

Energy Efficiency of a New Trifocal Intraocular Lens

NASA Astrophysics Data System (ADS)

Vega, F.; Alba-Bueno, F.; Millán, M. S.

2014-01-01

The light distribution among the far, intermediate and near foci of a new trifocal intraocular lens (IOL) is experimentally determined, as a function of the pupil size, from image analysis. The concept of focus energy efficiency is introduced because, in addition to the theoretical diffraction efficiency of the focus, it accounts for other factors that are naturally presented in the human eye such as the level of spherical aberration (SA) upon the IOL, light scattering at the diffractive steps or the depth of focus. The trifocal IOL is tested in-vitro in two eye models: the aberration-free ISO model, and a so called modified-ISO one that uses an artificial cornea with positive spherical SA in instead. The SA upon the IOL is measured with a Hartmann-Shack sensor and compared to the values of theoretical eye models. The results show, for large pupils, a notorious reduction of the energy efficiency of the far and near foci of the trifocal IOL due to two facts: the level of SA upon the IOL is larger than the value the lens is able to compensate for and there is significant light scattering at the diffractive steps. On the other hand, the energy efficiency of the intermediate focus for small pupils is enhanced by the contribution of the extended depth of focus of the near and far foci. Thus, while IOLs manufacturers tend to provide just the theoretical diffraction efficiency of the foci to show which would be the performance of the lens in terms of light distribution among the foci, our results put into evidence that this is better described by using the energy efficiency of the foci.

Forecasting jobs in the supply chain for investments in residential energy efficiency retrofits in Florida

NASA Astrophysics Data System (ADS)

Fobair, Richard C., II

This research presents a model for forecasting the numbers of jobs created in the energy efficiency retrofit (EER) supply chain resulting from an investment in upgrading residential buildings in Florida. This investigation examined material supply chains stretching from mining to project installation for three product types: insulation, windows/doors, and heating, ventilating, and air conditioning (HVAC) systems. Outputs from the model are provided for the project, sales, manufacturing, and mining level. The model utilizes reverse-estimation to forecast the numbers of jobs that result from an investment. Reverse-estimation is a process that deconstructs a total investment into its constituent parts. In this research, an investment is deconstructed into profit, overhead, and hard costs for each level of the supply chain and over multiple iterations of inter-industry exchanges. The model processes an investment amount, the type of work and method of contracting into a prediction of the number of jobs created. The deconstruction process utilizes data from the U.S. Economic Census. At each supply chain level, the cost of labor is reconfigured into full-time equivalent (FTE) jobs (i.e. equivalent to 40 hours per week for 52 weeks) utilizing loaded labor rates and a typical employee mix. The model is sensitive to adjustable variables, such as percentage of work performed per type of product, allocation of worker time per skill level, annual hours for FTE calculations, wage rate, and benefits. This research provides several new insights into job creation. First, it provides definitions that can be used for future research on jobs in supply chains related to energy efficiency. Second, it provides a methodology for future investigators to calculate jobs in a supply chain resulting from an investment in energy efficiency upgrades to a building. The methodology used in this research is unique because it examines gross employment at the sub-industry level for specific commodities. Most research on employment examines the net employment change (job creation less job destruction) at levels for regions, industries, and the aggregate economy. Third, it provides a forecast of the numbers of jobs for an investment in energy efficiency over the entire supply chain for the selected industries and the job factors for major levels of the supply chain.

Quantifying Adoption Rates and Energy Savings Over Time for Advanced Manufacturing Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanes, Rebecca; Carpenter Petri, Alberta C; Riddle, Matt

Energy-efficient manufacturing technologies can reduce energy consumption and lower operating costs for an individual manufacturing facility, but increased process complexity and the resulting risk of disruption means that manufacturers may be reluctant to adopt such technologies. In order to quantify potential energy savings at scales larger than a single facility, it is necessary to account for how quickly and how widely the technology will be adopted by manufacturers. This work develops a methodology for estimating energy-efficient manufacturing technology adoption rates using quantitative, objectively measurable technology characteristics, including energetic, economic and technical criteria. Twelve technology characteristics are considered, and each characteristicmore » is assigned an importance weight that reflects its impact on the overall technology adoption rate. Technology characteristic data and importance weights are used to calculate the adoption score, a number between 0 and 1 that represents how quickly the technology is likely to be adopted. The adoption score is then used to estimate parameters for the Bass diffusion curve, which quantifies the change in the number of new technology adopters in a population over time. Finally, energy savings at the sector level are calculated over time by multiplying the number of new technology adopters at each time step with the technology's facility-level energy savings. The proposed methodology will be applied to five state-of-the-art energy-efficient technologies in the carbon fiber composites sector, with technology data obtained from the Department of Energy's 2016 bandwidth study. Because the importance weights used in estimating the Bass curve parameters are subjective, a sensitivity analysis will be performed on the weights to obtain a range of parameters for each technology. The potential energy savings for each technology and the rate at which each technology is adopted in the sector are quantified and used to identify the technologies which offer the greatest cumulative sector-level energy savings over a period of 20 years. Preliminary analysis indicates that relatively simple technologies, such as efficient furnaces, will be adopted more quickly and result in greater cumulative energy savings compared to more complex technologies that require process retrofitting, such as advanced control systems.« less

Estimate of Cost-Effective Potential for Minimum Efficiency Performance Standards in 13 Major World Economies Energy Savings, Environmental and Financial Impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Letschert, Virginie E.; Bojda, Nicholas; Ke, Jing

2012-07-01

This study analyzes the financial impacts on consumers of minimum efficiency performance standards (MEPS) for appliances that could be implemented in 13 major economies around the world. We use the Bottom-Up Energy Analysis System (BUENAS), developed at Lawrence Berkeley National Laboratory (LBNL), to analyze various appliance efficiency target levels to estimate the net present value (NPV) of policies designed to provide maximum energy savings while not penalizing consumers financially. These policies constitute what we call the “cost-effective potential” (CEP) scenario. The CEP scenario is designed to answer the question: How high can we raise the efficiency bar in mandatory programsmore » while still saving consumers money?« less

[Environmental efficiency evaluation under carbon emission constraint in Western China].

PubMed

Rong, Jian-bo; Yan, Li-jiao; Huang, Shao-rong; Zhang, Ge

2015-06-01

This research used the SBM model based on undesirable outputs to measure the static environmental efficiency of Western China under carbon emission constraint from 2000 to 2012. The researchers also utilized the Malmquist index to further analyze the change tendency of environmental efficiency. Additionally, Tobit regression analysis was used to study the factors relevant to environmental efficiency. Practical solutions to improve environmental quality in Western China were put forward. The study showed that in Western China, environmental efficiency with carbon emission constraint was significantly lower than that without carbon emission constraint, and the difference could be described as an inverse U-shaped curve which increased at first and then decreased. Guang-xi and Inner Mongolia, the two provinces met the effective environmental efficiency levels all the time under carbon emission constraint. However, the five provinces of Guizhou, Gansu, Qinghai, Ningxia and Xinjiang did not. Furthermore, Ningxia had the lowest level of environmental efficiency, with a score between 0.281-0.386. Although the environmental efficiency of most provinces was currently at an ineffective level, the environmental efficiency quality was gradually improving at an average speed of 6.6%. Excessive CO2 emission and a large amount of energy consumption were the primary factors causing environmental inefficiency in Western China, and energy intensity had the most negative impact on the environmental efficiency. The increase of import and export trade reduced the environmental efficiency significantly in Western China, while the increase of foreign direct investment had a positive effect on its environmental efficiency.

Interactions between Energy Efficiency Programs funded under the Recovery Act and Utility Customer-Funded Energy Efficiency Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldman, Charles A.; Stuart, Elizabeth; Hoffman, Ian

2011-02-25

Since the spring of 2009, billions of federal dollars have been allocated to state and local governments as grants for energy efficiency and renewable energy projects and programs. The scale of this American Reinvestment and Recovery Act (ARRA) funding, focused on 'shovel-ready' projects to create and retain jobs, is unprecedented. Thousands of newly funded players - cities, counties, states, and tribes - and thousands of programs and projects are entering the existing landscape of energy efficiency programs for the first time or expanding their reach. The nation's experience base with energy efficiency is growing enormously, fed by federal dollars andmore » driven by broader objectives than saving energy alone. State and local officials made countless choices in developing portfolios of ARRA-funded energy efficiency programs and deciding how their programs would relate to existing efficiency programs funded by utility customers. Those choices are worth examining as bellwethers of a future world where there may be multiple program administrators and funding sources in many states. What are the opportunities and challenges of this new environment? What short- and long-term impacts will this large, infusion of funds have on utility customer-funded programs; for example, on infrastructure for delivering energy efficiency services or on customer willingness to invest in energy efficiency? To what extent has the attribution of energy savings been a critical issue, especially where administrators of utility customer-funded energy efficiency programs have performance or shareholder incentives? Do the new ARRA-funded energy efficiency programs provide insights on roles or activities that are particularly well-suited to state and local program administrators vs. administrators or implementers of utility customer-funded programs? The answers could have important implications for the future of U.S. energy efficiency. This report focuses on a selected set of ARRA-funded energy efficiency programs administered by state energy offices: the State Energy Program (SEP) formula grants, the portion of Energy Efficiency and Conservation Block Grant (EECBG) formula funds administered directly by states, and the State Energy Efficient Appliance Rebate Program (SEEARP). Since these ARRA programs devote significant monies to energy efficiency and serve similar markets as utility customer-funded programs, there are frequent interactions between programs. We exclude the DOE low-income weatherization program and EECBG funding awarded directly to the over 2,200 cities, counties and tribes from our study to keep its scope manageable. We summarize the energy efficiency program design and funding choices made by the 50 state energy offices, 5 territories and the District of Columbia. We then focus on the specific choices made in 12 case study states. These states were selected based on the level of utility customer program funding, diversity of program administrator models, and geographic diversity. Based on interviews with more than 80 energy efficiency actors in those 12 states, we draw observations about states strategies for use of Recovery Act funds. We examine interactions between ARRA programs and utility customer-funded energy efficiency programs in terms of program planning, program design and implementation, policy issues, and potential long-term impacts. We consider how the existing regulatory policy framework and energy efficiency programs in these 12 states may have impacted development of these selected ARRA programs. Finally, we summarize key trends and highlight issues that evaluators of these ARRA programs may want to examine in more depth in their process and impact evaluations.« less

The energetics of fish growth and how it constrains food-web trophic structure.

PubMed

Barneche, Diego R; Allen, Andrew P

2018-06-01

The allocation of metabolic energy to growth fundamentally influences all levels of biological organisation. Here we use a first-principles theoretical model to characterise the energetics of fish growth at distinct ontogenetic stages and in distinct thermal regimes. Empirically, we show that the mass scaling of growth rates follows that of metabolic rate, and is somewhat steeper at earlier ontogenetic stages. We also demonstrate that the cost of growth, E m , varies substantially among fishes, and that it may increase with temperature, trophic level and level of activity. Theoretically, we show that E m is a primary determinant of the efficiency of energy transfer across trophic levels, and that energy is transferred more efficiently between trophic levels if the prey are young and sedentary. Overall, our study demonstrates the importance of characterising the energetics of individual growth in order to understand constraints on the structure of food webs and ecosystems. © 2018 John Wiley & Sons Ltd/CNRS.

Energy-optimal path planning by stochastic dynamically orthogonal level-set optimization

NASA Astrophysics Data System (ADS)

Subramani, Deepak N.; Lermusiaux, Pierre F. J.

2016-04-01

A stochastic optimization methodology is formulated for computing energy-optimal paths from among time-optimal paths of autonomous vehicles navigating in a dynamic flow field. Based on partial differential equations, the methodology rigorously leverages the level-set equation that governs time-optimal reachability fronts for a given relative vehicle-speed function. To set up the energy optimization, the relative vehicle-speed and headings are considered to be stochastic and new stochastic Dynamically Orthogonal (DO) level-set equations are derived. Their solution provides the distribution of time-optimal reachability fronts and corresponding distribution of time-optimal paths. An optimization is then performed on the vehicle's energy-time joint distribution to select the energy-optimal paths for each arrival time, among all stochastic time-optimal paths for that arrival time. Numerical schemes to solve the reduced stochastic DO level-set equations are obtained, and accuracy and efficiency considerations are discussed. These reduced equations are first shown to be efficient at solving the governing stochastic level-sets, in part by comparisons with direct Monte Carlo simulations. To validate the methodology and illustrate its accuracy, comparisons with semi-analytical energy-optimal path solutions are then completed. In particular, we consider the energy-optimal crossing of a canonical steady front and set up its semi-analytical solution using a energy-time nested nonlinear double-optimization scheme. We then showcase the inner workings and nuances of the energy-optimal path planning, considering different mission scenarios. Finally, we study and discuss results of energy-optimal missions in a wind-driven barotropic quasi-geostrophic double-gyre ocean circulation.

Improving energy efficiency via smart building energy management systems. A comparison with policy measures

DOE PAGES

Rocha, Paula; Siddiqui, Afzal; Stadler, Michael

2014-12-09

In this study, to foster the transition to more sustainable energy systems, policymakers have been approving measures to improve energy efficiency as well as promoting smart grids. In this setting, building managers are encouraged to adapt their energy operations to real-time market and weather conditions. Yet, most fail to do so as they rely on conventional building energy management systems (BEMS) that have static temperature set points for heating and cooling equipment. In this paper, we investigate how effective policy measures are at improving building-level energy efficiency compared to a smart BEMS with dynamic temperature set points. To this end,more » we present an integrated optimisation model mimicking the smart BEMS that combines decisions on heating and cooling systems operations with decisions on energy sourcing. Using data from an Austrian and a Spanish building, we find that the smart BEMS results in greater reduction in energy consumption than a conventional BEMS with policy measures.« less

Empirical valence bond models for reactive potential energy surfaces: a parallel multilevel genetic program approach.

PubMed

Bellucci, Michael A; Coker, David F

2011-07-28

We describe a new method for constructing empirical valence bond potential energy surfaces using a parallel multilevel genetic program (PMLGP). Genetic programs can be used to perform an efficient search through function space and parameter space to find the best functions and sets of parameters that fit energies obtained by ab initio electronic structure calculations. Building on the traditional genetic program approach, the PMLGP utilizes a hierarchy of genetic programming on two different levels. The lower level genetic programs are used to optimize coevolving populations in parallel while the higher level genetic program (HLGP) is used to optimize the genetic operator probabilities of the lower level genetic programs. The HLGP allows the algorithm to dynamically learn the mutation or combination of mutations that most effectively increase the fitness of the populations, causing a significant increase in the algorithm's accuracy and efficiency. The algorithm's accuracy and efficiency is tested against a standard parallel genetic program with a variety of one-dimensional test cases. Subsequently, the PMLGP is utilized to obtain an accurate empirical valence bond model for proton transfer in 3-hydroxy-gamma-pyrone in gas phase and protic solvent. © 2011 American Institute of Physics

Shockley-Read-Hall recombination in pre-filled and photo-filled intermediate band solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayani, Maryam Gholami; Reenaas, Turid Worren, E-mail: turid.reenaas@ntnu.no

2014-08-18

In this work, we study how Shockley-Read-Hall (SRH) recombination via energy levels in the bandgap, caused by defects or impurities, affects the performance of both photo-filled and pre-filled intermediate band solar cells (IBSCs). For a pre-filled cell, the IB is half-filled in equilibrium, while it is empty for the photo-filled cell in equilibrium. The energy level, density, and capture cross-sections of the defects/impurities are varied systematically. We find that the photo-filled cells are, in general, less efficient than pre-filled cells, except when the defect level is between the conduction band and the IB. In that case, for a range ofmore » light intensities, the photo-filled cell performs better than the pre-filled. When the defect level is at the same energy as the IB, the efficiency is above 82% of the defect-free case, when less than 50% of the states at the IB lead to SRH recombination. This shows that even if SRH recombination via the IB takes place, high efficiencies can be achieved. We also show that band gap optimization can be used to reduce the SRH recombination.« less

Smart integrated microsystems: the energy efficiency challenge (Conference Presentation) (Plenary Presentation)

NASA Astrophysics Data System (ADS)

Benini, Luca

2017-06-01

The "internet of everything" envisions trillions of connected objects loaded with high-bandwidth sensors requiring massive amounts of local signal processing, fusion, pattern extraction and classification. From the computational viewpoint, the challenge is formidable and can be addressed only by pushing computing fabrics toward massive parallelism and brain-like energy efficiency levels. CMOS technology can still take us a long way toward this goal, but technology scaling is losing steam. Energy efficiency improvement will increasingly hinge on architecture, circuits, design techniques such as heterogeneous 3D integration, mixed-signal preprocessing, event-based approximate computing and non-Von-Neumann architectures for scalable acceleration.

AVERT Main Module Quick Start Guide

EPA Pesticide Factsheets

Learn how to get started with the AVERT tool, which guides non-experts in evaluating county-level emissions displaced at electric power plants by energy efficiency and renewable energy policies and programs.

Energy Efficiency and Universal Design in Home Renovations - A Comparative Review.

PubMed

Kapedani, Ermal; Herssens, Jasmien; Verbeeck, Griet

2016-01-01

Policy and societal objectives indicate a large need for housing renovations that both accommodate lifelong living and significantly increase energy efficiency. However, these two areas of research are not yet examined in conjunction and this paper hypothesizes this as a missed opportunity to create better renovation concepts. The paper outlines a comparative review on research in Energy Efficiency and Universal Design in order to find the similarities and differences in both depth and breadth of knowledge. Scientific literature in the two fields reveals a disparate depth of knowledge in areas of theory, research approach, and degree of implementation in society. Universal Design and Energy Efficiency are part of a trajectory of expanding scope towards greater sustainability and, although social urgency has been a driver of the research intensity and approach in both fields, in energy efficiency there is an engineering, problem solving approach while Universal Design has a more sociological, user-focused one. These different approaches are reflected in the way home owners in Energy Efficiency research are viewed as consumers and decision makers whose drivers are studied, while Universal Design treats home owners as informants in the design process and studies their needs. There is an inherent difficulty in directly merging Universal Design and Energy Efficiency at a conceptual level because Energy Efficiency is understood as a set of measures, i.e. a product, while Universal Design is part of a (design) process. The conceptual difference is apparent in their implementation as well. Internationally energy efficiency in housing has been largely imposed through legislation, while legislation directly mandating Universal Design is either non-existent or it has an explicit focus on accessibility. However, Energy Efficiency and Universal Design can be complementary concepts and, even though it is more complex than expected, the combination offers possibilities to advance knowledge in both fields.

Study of Conical Pulsed Inductive Thruster with Multiple Modes of Operation

NASA Technical Reports Server (NTRS)

Miller, Robert; Eskridge, Richard; Martin, Adam; Rose, Frank

2008-01-01

An electrodeless, pulsed, inductively coupled thruster has several advantages over current electric propulsion designs. The efficiency of a pulsed inductive thruster is dependent upon the pulse characteristics of the device. Therefore, these thrusters are throttleable over a wide range of thrust levels by varying the pulse rate without affecting the thruster efficiency. In addition, by controlling the pulse energy and the mass bit together, the ISP of the thruster can also be varied with minimal efficiency loss over a wide range of ISP levels. Pulsed inductive thrusters will work with a multitude of propellants, including ammonia. Thus, a single pulsed inductive thruster could be used to handle a multitude of mission needs from high thrust to high ISP with one propulsion solution that would be variable in flight. A conical pulsed inductive lab thruster has been built to study this form of electric propulsion in detail. This thruster incorporates many advantages that are meant to enable this technology as a viable space propulsion technology. These advantages include incorporation of solid state switch technology for all switching needs of the thruster and pre-ionization of the propellant gas prior to acceleration. Pre-ionizing will significantly improve coupling efficiency between drive and bias fields and the plasma. This enables lower pulse energy levels without efficiency reduction. Pre-ionization can be accomplished at a small fraction of the drive pulse energy.

Growth and energy budget of juvenile lenok Brachymystax lenok in relation to ration level

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Zhongjie; Zhang, Tanglin; Yuan, Jing; Mou, Zhenbo; Liu, Jiashou

2015-03-01

We evaluated the effect of ration level (RL) on the growth and energy budget of lenok Brachymystax lenok. Juvenile lenok (initial mean body weight 3.06±0.13 g) were fed for 21 d at five different ration levels: starvation, 2%, 3%, 4% bwd (body weight per day, based on initial mean values), and apparent satiation. Feed consumption, apparent digestibility, and growth were directly measured. Specific growth rates in terms of wet weight, dry weight, protein, and energy increased logarithmically with an increase in ration levels. The relationship between specific growth rate in terms of wet weight (SGRw, %/d) and RL (%) was characterized by a decelerating curve: SGRw=-1.417+3.166ln(RL+1). The apparent digestibility coefficients of energy exhibited a decreasing pattern with increasing ration level, and there was a significant difference among different RLs. Body composition was significantly affected by ration size. The relationship between feed efficiency rate in terms of energy (FERe) and RL was: FERe=-14.167+23.793RL-3.367(RL)2, and the maximum FERe was observed at a 3.53% ration. The maintenance requirement for energy of juvenile lenok was 105.39 kJ BW (kg)-0.80/d, the utilization efficiency of DE for growth was 0.496. The energy budget equation at satiation was: 100IE=29.03FE+5.78(ZE+UE)+39.56 HE+25.63 RE, where IE is feed energy, FE is fecal energy, ZE+UE is excretory energy, HE is heat production, and RE is recovered energy. Our results suggest that the most suitable feeding rate for juvenile lenok aquaculture for wet weight growth is 2.89% bwd, whereas for energy growth, the suggested rate is 3.53% bwd at this growth stage.

Research and Energy Efficiency: Selected Success Stories

DOE R&D Accomplishments Database

Garland, P. W.; Garland, R. W.

1997-06-26

Energy use and energy technology play critical roles in the U.S. economy and modern society. The Department of Energy (DOE) conducts civilian energy research and development (R&D) programs for the purpose of identifying promising technologies that promote energy security, energy efficiency, and renewable energy use. DOE-sponsored research ranges from basic investigation of phenomena all the way through development of applied technology in partnership with industry. DOE`s research programs are conducted in support of national strategic energy objectives, however austere financial times have dictated that R&D programs be measured in terms of cost vs. benefit. In some cases it is difficult to measure the return on investment for the basic "curiosity-driven" research, however many applied technology development programs have resulted in measurable commercial successes. The DOE has published summaries of their most successful applied technology energy R&D programs. In this paper, we will discuss five examples from the Building Technologies area of the DOE Energy Efficiency program. Each story will describe the technology, discuss the level of federal funding, and discuss the returns in terms of energy savings, cost savings, or national economic impacts.

Measurement and decomposition of energy efficiency of Northeast China-based on super efficiency DEA model and Malmquist index.

PubMed

Ma, Xiaojun; Liu, Yan; Wei, Xiaoxue; Li, Yifan; Zheng, Mengchen; Li, Yudong; Cheng, Chaochao; Wu, Yumei; Liu, Zhaonan; Yu, Yuanbo

2017-08-01

Nowadays, environment problem has become the international hot issue. Experts and scholars pay more and more attention to the energy efficiency. Unlike most studies, which analyze the changes of TFEE in inter-provincial or regional cities, TFEE is calculated with the ratio of target energy value and actual energy input based on data in cities of prefecture levels, which would be more accurate. Many researches regard TFP as TFEE to do analysis from the provincial perspective. This paper is intended to calculate more reliably by super efficiency DEA, observe the changes of TFEE, and analyze its relation with TFP, and it proves that TFP is not equal to TFEE. Additionally, the internal influences of the TFEE are obtained via the Malmquist index decomposition. The external influences of the TFFE are analyzed afterward based on the Tobit models. Analysis results demonstrate that Heilongjiang has the highest TFEE followed by Jilin, and Liaoning has the lowest TFEE. Eventually, some policy suggestions are proposed for the influences of energy efficiency and study results.

Efficiency of energy recovery from waste incineration, in the light of the new Waste Framework Directive.

PubMed

Grosso, Mario; Motta, Astrid; Rigamonti, Lucia

2010-07-01

This paper deals with a key issue related to municipal waste incineration, which is the efficiency of energy recovery. A strong driver for improving the energy performances of waste-to-energy plants is the recent Waste Framework Directive (Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain Directives), which allows high efficiency installations to benefit from a status of "recovery" rather than "disposal". The change in designation means a step up in the waste hierarchy, where the lowest level of priority is now restricted to landfilling and low efficiency wastes incineration. The so-called "R1 formula" reported in the Directive, which counts for both production of power and heat, is critically analyzed and correlated to the more scientific-based approach of exergy efficiency. The results obtained for waste-to-energy plants currently operating in Europe reveal some significant differences in their performance, mainly related to the average size and to the availability of a heat market (district heating). Copyright (c) 2010 Elsevier Ltd. All rights reserved.

9.0% power conversion efficiency from ternary all-polymer solar cells

DOE PAGES

Li, Zhaojun; Xu, Xiaofeng; Zhang, Wei; ...

2017-01-01

High-performance ternary all-polymer solar cells with outstanding efficiency of 9.0% are realized by incorporating two donor and one acceptor polymers with complementary absorption and proper energy level alignment.

Efficient solar-driven synthesis, carbon capture, and desalinization, STEP: solar thermal electrochemical production of fuels, metals, bleach.

PubMed

Licht, S

2011-12-15

STEP (solar thermal electrochemical production) theory is derived and experimentally verified for the electrosynthesis of energetic molecules at solar energy efficiency greater than any photovoltaic conversion efficiency. In STEP the efficient formation of metals, fuels, chlorine, and carbon capture is driven by solar thermal heated endothermic electrolyses of concentrated reactants occuring at a voltage below that of the room temperature energy stored in the products. One example is CO(2) , which is reduced to either fuels or storable carbon at a solar efficiency of over 50% due to a synergy of efficient solar thermal absorption and electrochemical conversion at high temperature and reactant concentration. CO(2) -free production of iron by STEP, from iron ore, occurs via Fe(III) in molten carbonate. Water is efficiently split to hydrogen by molten hydroxide electrolysis, and chlorine, sodium, and magnesium from molten chlorides. A pathway is provided for the STEP decrease of atmospheric carbon dioxide levels to pre-industial age levels in 10 years. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scout: An Impact Analysis Tool for Building Energy-Efficiency Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Chioke; Langevin, Jared; Roth, Amir

Evaluating the national impacts of candidate U.S. building energy-efficiency technologies has historically been difficult for organizations with large energy efficiency portfolios. In particular, normalizing results from technology-specific impact studies is time-consuming when those studies do not use comparable assumptions about the underlying building stock. To equitably evaluate its technology research, development, and deployment portfolio, the U.S. Department of Energy's Building Technologies Office has developed Scout, a software tool that quantitatively assesses the energy and CO2 impacts of building energy-efficiency measures on the national building stock. Scout efficiency measures improve upon the unit performance and/or lifetime operational costs of an equipmentmore » stock baseline that is determined from the U.S. Energy Information Administration Annual Energy Outlook (AEO). Scout measures are characterized by a market entry and exit year, unit performance level, cost, and lifetime. To evaluate measures on a consistent basis, Scout uses EnergyPlus simulation on prototype building models to translate measure performance specifications to whole-building energy savings; these savings impacts are then extended to a national scale using floor area weighting factors. Scout represents evolution in the building stock over time using AEO projections for new construction, retrofit, and equipment replacements, and competes technologies within market segments under multiple adoption scenarios. Scout and its efficiency measures are open-source, as is the EnergyPlus whole building simulation framework that is used to evaluate measure performance. The program is currently under active development and will be formally released once an initial set of measures has been analyzed and reviewed.« less

Towards energy efficient operation of Heating, Ventilation and Air Conditioning systems via advanced supervisory control design

NASA Astrophysics Data System (ADS)

Oswiecinska, A.; Hibbs, J.; Zajic, I.; Burnham, K. J.

2015-11-01

This paper presents conceptual control solution for reliable and energy efficient operation of heating, ventilation and air conditioning (HVAC) systems used in large volume building applications, e.g. warehouse facilities or exhibition centres. Advanced two-level scalable control solution, designed to extend capabilities of the existing low-level control strategies via remote internet connection, is presented. The high-level, supervisory controller is based on Model Predictive Control (MPC) architecture, which is the state-of-the-art for indoor climate control systems. The innovative approach benefits from using passive heating and cooling control strategies for reducing the HVAC system operational costs, while ensuring that required environmental conditions are met.

International Experience in Standards and Labeling Programs for Rice Cookers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Nan; Zheng, Nina

China has had an active program on energy efficiency standards for household appliances since the mid-1990s. Rice cooker is among the first to be subject to such mandatory regulation, since it is one of the most prevalent electric appliances in Chinese households. Since first introduced in 1989, the minimum energy efficiency standard for rice cookers has not been revised. Therefore, the potential for energy saving is considerable. Initial analysis from CNIS indicates that potential carbon savings is likely to reach 7.6 million tons of CO2 by the 10th year of the standard implementation. Since September 2007, CNIS has been workingmore » with various groups to develop the new standard for rice cookers. With The Energy Foundation's support, LBNL has assisted CNIS in the revision of the minimum energy efficiency standard for rice cookers that is expected to be effective in 2009. Specifically, work has been in the following areas: assistance in developing consumer survey on usage pattern of rice cookers, review of international standards, review of international test procedures, comparison of the international standards and test procedures, and assessment of technical options of reducing energy use. This report particularly summarizes the findings of reviewing international standards and technical options of reducing energy consumption. The report consists of an overview of rice cooker standards and labeling programs and testing procedures in Hong Kong, South Korea, Japan and Thailand, and Japan's case study in developing energy efficiency rice cooker technologies and rice cooker efficiency programs. The results from the analysis can be summarized as the follows: Hong Kong has a Voluntary Energy Efficiency Labeling scheme for electric rice cookers initiated in 2001, with revision implemented in 2007; South Korea has both MEPS and Mandatory Energy Efficiency Label targeting the same category of rice cookers as Hong Kong; Thailand's voluntary endorsement labeling program is similar to Hong Kong in program design but has 5 efficiency grades; Japan's program is distinct in its adoption of the 'Top Runner' approach, in which, the future efficiency standards is set based on the efficiency levels of the most efficient product in the current domestic market. Although the standards are voluntary, penalties can still be evoked if the average efficiency target is not met. Both Hong Kong and South Korea's tests involve pouring water into the inner pot equal to 80% of its rated volume; however, white rice is used as a load for its tests in Hong Kong whereas no rice is used for tests in South Korea. In Japan's case, water level specified by the manufactures is used and milled rice is used as a load only partially in the tests. Moreover, Japan does not conduct heat efficiency test but its energy consumption measurements tests are much more complex, with 4 different tests are conducted to determine the annual average energy consumption. Hong Kong and Thailand both set Minimum Allowable Heat Efficiency for different rated wattages. The energy efficiency requirements are identical except that the minimum heat efficiency in Thailand is 1 percentage point higher for all rated power categories. In South Korea, MEPS and label's energy efficiency grades are determined by the rice cooker's Rated Energy Efficiency for induction, non-induction, pressure, nonpressure rice cookers. Japan's target standard values are set for electromagnetic induction heating products and non-electromagnetic induction heating products by different size of rice cookers. Specific formulas are used by type and size depending on the mass of water evaporation of the rice cookers. Japan has been the leading country in technology development of various types of rice cookers, and developed concrete energy efficiency standards for rice cookers. However, as consumers in Japan emphasize the deliciousness of cooked rice over other factors, many types of models were developed to improve the taste of cooked rice. Nonetheless, the efficiency of electromagnetic induction heating (IH) rice cookers in warm mode has improved approximately 12 percent from 1993 to 2004 due to the 'low temperature warming method' developed by manufacturers. The Energy Conservation Center of Japan (IEEJ) releases energy saving products database on the web regularly, on which the energy saving performance of each product is listed and ranked. Energy saving in rice cookers mostly rest with insulation of the pot. Technology developed to improve the energy efficiency of the rice cookers includes providing vacuum layers on both side of the pot, using copper-plated materials, and double stainless layer lid that can be heated and steam can run in between the two layers to speed the heating process.« less

Long-term Energy and Emissions Savings Potential in New York City Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatt, Vatsal; Lee, John; Klein, Yehuda

2012-09-30

The New York State Energy Research and Development Authority (NYSERDA) partnered with the Brookhaven National Laboratory (BNL) and the City University of New York (CUNY) to develop an integrated methodology that is capable of quantifying the impact of energy efficiency and load management options in buildings, including CUNY’s campus buildings, housing projects, hospitals, and hotels, while capturing the synergies and offsets in a complex and integrated energy-environmental system. The results of this work serve as a guideline in implementing urban energy efficiency and other forms of urban environmental improvement through cost-effective planning at the institutional and local level.

Evaluating the efficiency of nuclear energy policies: an empirical examination for 26 countries.

PubMed

Gozgor, Giray; Demir, Ender

2017-08-01

The decarbonization of the global economy is an urgent concern. As a potential solution, it can be important to understand the efficiency of nuclear energy policies. For this purpose, the paper analyzes whether there is a unit root in nuclear energy consumption in 26 countries and it uses the unit root tests with two endogenous (unknown) structural breaks. The paper finds that nuclear energy consumption is stationary around a level and the time trend in 25 of 26 countries and nuclear energy consumption contains a unit root only in France. The paper also discusses the potential implications of the findings.

Residual energy level based clustering routing protocol for wireless sensor networks

NASA Astrophysics Data System (ADS)

Yuan, Xu; Zhong, Fangming; Chen, Zhikui; Yang, Deli

2015-12-01

The wireless sensor networks, which nodes prone to premature death, with unbalanced energy consumption and a short life time, influenced the promotion and application of this technology in internet of things in agriculture. This paper proposes a clustering routing protocol based on the residual energy level (RELCP). RELCP includes three stages: the selection of cluster head, establishment of cluster and data transmission. RELCP considers the remaining energy level and distance to base station, while election of cluster head nodes and data transmitting. Simulation results demonstrate that the protocol can efficiently balance the energy dissipation of all nodes, and prolong the network lifetime.

2.097μ Cth:YAG flashlamp pumped high energy high efficiency laser operation (patent pending)

NASA Astrophysics Data System (ADS)

Bar-Joseph, Dan

2018-02-01

Flashlamp pumped Cth:YAG lasers are mainly used in medical applications (urology). The main laser transition is at 2.13μ and is called a quasi-three level having an emission cross-section of 7x10-21 cm2 and a ground state absorption of approximately 5%/cm. Because of the relatively low absorption, combined with a modest emission cross-section, the laser requires high reflectivity output coupling, and therefore high intra-cavity energy density which limits the output to approximately 4J/pulse for reliable operation. This paper will describe a method of efficiently generating high output energy at low intra-cavity energy density by using an alternative 2.097μ transition having an emission cross-section of 5x10-21 cm2 and a ground level absorption of approximately 14%/cm.

Application of higher energy collisional dissociation (HCD) to the fragmentation of new DOTA-based labels and N-termini DOTA-labeled peptides.

PubMed

El-Khatib, A H; He, Y; Esteban-Fernández, D; Linscheid, M W

2017-08-01

1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) derivatives are applied in quantitative proteomics owing to their ability to react with different functional groups, to harbor lanthanoides and hence their compatibility with molecular and elemental mass spectrometry. The new DOTA derivatives, namely Ln-MeCAT-Click and Ln-DOTA-Dimedone, allow efficient thiol labeling and targeting sulfenation as an important post-translational modification, respectively. Quantitative applications require the investigation of fragmentation behavior of these reagents. Therefore, the fragmentation behavior of Ln-MeCAT-Click and Ln-DOTA-Dimedone was studied using collision-induced dissociation (CID), infrared multiphoton dissociation (IRMPD) and higher-energy collision dissociation (HCD) using different energy levels, and the efficiency of reporter ion production was estimated. The efficiency of characteristic fragment formation was in the order IRMPD > HCD (normal energy level) > CID. On the other hand, the application of HCD at high energy levels (HCD@HE; NCE > 250%) resulted in a significant increase in reporter ion production (33-54%). This new strategy was successfully applied to generate label-specific reporter ions for DOTA amino labeling at the N-termini and in a quantitative fashion for the estimation of amino:thiol ratio in peptides. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Cooperative and Integrated Vehicle and Intersection Control for Energy Efficiency (CIVIC-E²)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hou, Yunfei; Seliman, Salaheldeen M. S.; Wang, Enshu

Recent advances in connected vehicle technologies enable vehicles and signal controllers to cooperate and improve the traffic management at intersections. This paper explores the opportunity for cooperative and integrated vehicle and intersection control for energy efficiency (CIVIC-E 2) to contribute to a more sustainable transportation system. We propose a two-level approach that jointly optimizes the traffic signal timing and vehicles' approach speed, with the objective being to minimize total energy consumption for all vehicles passing through an isolated intersection. More specifically, at the intersection level, a dynamic programming algorithm is designed to find the optimal signal timing by explicitly consideringmore » the arrival time and energy profile of each vehicle. At the vehicle level, a model predictive control strategy is adopted to ensure that vehicles pass through the intersection in a timely fashion. Our simulation study has shown that the proposed CIVIC-E 2 system can significantly improve intersection performance under various traffic conditions. Compared with conventional fixed-time and actuated signal control strategies, the proposed algorithm can reduce energy consumption and queue length by up to 31% and 95%, respectively.« less

Cooperative and Integrated Vehicle and Intersection Control for Energy Efficiency (CIVIC-E²)

DOE PAGES

Hou, Yunfei; Seliman, Salaheldeen M. S.; Wang, Enshu; ...

2018-02-15

Recent advances in connected vehicle technologies enable vehicles and signal controllers to cooperate and improve the traffic management at intersections. This paper explores the opportunity for cooperative and integrated vehicle and intersection control for energy efficiency (CIVIC-E 2) to contribute to a more sustainable transportation system. We propose a two-level approach that jointly optimizes the traffic signal timing and vehicles' approach speed, with the objective being to minimize total energy consumption for all vehicles passing through an isolated intersection. More specifically, at the intersection level, a dynamic programming algorithm is designed to find the optimal signal timing by explicitly consideringmore » the arrival time and energy profile of each vehicle. At the vehicle level, a model predictive control strategy is adopted to ensure that vehicles pass through the intersection in a timely fashion. Our simulation study has shown that the proposed CIVIC-E 2 system can significantly improve intersection performance under various traffic conditions. Compared with conventional fixed-time and actuated signal control strategies, the proposed algorithm can reduce energy consumption and queue length by up to 31% and 95%, respectively.« less

Parallel elastic elements improve energy efficiency on the STEPPR bipedal walking robot

DOE PAGES

Mazumdar, Anirban; Spencer, Steven J.; Hobart, Clinton; ...

2016-11-23

This study describes how parallel elastic elements can be used to reduce energy consumption in the electric motor driven, fully-actuated, STEPPR bipedal walking robot without compromising or significantly limiting locomotive behaviors. A physically motivated approach is used to illustrate how selectively-engaging springs for hip adduction and ankle flexion predict benefits for three different flat ground walking gaits: human walking, human-like robot walking and crouched robot walking. Based on locomotion data, springs are designed and substantial reductions in power consumption are demonstrated using a bench dynamometer. These lessons are then applied to STEPPR (Sandia Transmission-Efficient Prototype Promoting Research), a fully actuatedmore » bipedal robot designed to explore the impact of tailored joint mechanisms on walking efficiency. Featuring high-torque brushless DC motors, efficient low-ratio transmissions, and high fidelity torque control, STEPPR provides the ability to incorporate novel joint-level mechanisms without dramatically altering high level control. Unique parallel elastic designs are incorporated into STEPPR, and walking data shows that hip adduction and ankle flexion springs significantly reduce the required actuator energy at those joints for several gaits. These results suggest that parallel joint springs offer a promising means of supporting quasi-static joint torques due to body mass during walking, relieving motors of the need to support these torques and substantially improving locomotive energy efficiency.« less

Parallel elastic elements improve energy efficiency on the STEPPR bipedal walking robot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazumdar, Anirban; Spencer, Steven J.; Hobart, Clinton

This study describes how parallel elastic elements can be used to reduce energy consumption in the electric motor driven, fully-actuated, STEPPR bipedal walking robot without compromising or significantly limiting locomotive behaviors. A physically motivated approach is used to illustrate how selectively-engaging springs for hip adduction and ankle flexion predict benefits for three different flat ground walking gaits: human walking, human-like robot walking and crouched robot walking. Based on locomotion data, springs are designed and substantial reductions in power consumption are demonstrated using a bench dynamometer. These lessons are then applied to STEPPR (Sandia Transmission-Efficient Prototype Promoting Research), a fully actuatedmore » bipedal robot designed to explore the impact of tailored joint mechanisms on walking efficiency. Featuring high-torque brushless DC motors, efficient low-ratio transmissions, and high fidelity torque control, STEPPR provides the ability to incorporate novel joint-level mechanisms without dramatically altering high level control. Unique parallel elastic designs are incorporated into STEPPR, and walking data shows that hip adduction and ankle flexion springs significantly reduce the required actuator energy at those joints for several gaits. These results suggest that parallel joint springs offer a promising means of supporting quasi-static joint torques due to body mass during walking, relieving motors of the need to support these torques and substantially improving locomotive energy efficiency.« less

Energy conservation and efficiency in manufacturing: Employee decisions and actions

NASA Astrophysics Data System (ADS)

Corson, Marla D.

Energy conservation and intensity reduction efforts are becoming increasingly more prevalent and ultimately necessary, especially for energy-intensive manufacturing companies in particular to stay in business. Typical actions are to change technology, and thus, realize an energy cost savings in overall utilities. However, in today's competitive market, with climate change and other environmental impacts as well, it is necessary for the cost of energy to be valued as a cost of making a product, and thus, managed at the same level as the cost of labor or materials. This research assessed human behavior at the individual and organizational levels both at work and at home that either prompted or prohibited employees from taking daily action to conserve energy or develop greater energy efficient practices. Ultimately, the questions began with questions regarding employee views and knowledge of energy at work and at home and what drives both behaviors toward conservation or efficiency. And, the contribution identifies the key drivers, barriers, and/or incentives that affect those behaviors. The results of this study show that the key driver and motivator for energy conservation both at home and work is cost savings. The study showed that to further motivate individuals to conserve energy at home and work, more knowledge of the impact their actions have or could have as well as tools would be needed. The most poinient aspect of the research was the level of importance placed on energy conservation and the desire to conserve. The feedback given to the open ended questions was quite impressive regarding what employees have done and continue to do particularly within their homes to conserve energy. These findings brought about final recommendations that were in fact not expected but could significantly influence an increase in energy conservation at work by leveraging the existing desire to conserve which is a key component to decision making.

The thermoelectric efficiency of quantum dots in indium arsenide/indium phosphide nanowires

NASA Astrophysics Data System (ADS)

Hoffmann, Eric A.

State of the art semiconductor materials engineering provides the possibility to fabricate devices on the lower end of the mesoscopic scale and confine only a handful of electrons to a region of space. When the thermal energy is reduced below the energetic quantum level spacing, the confined electrons assume energy levels akin to the core-shell structure of natural atoms. Such "artificial atoms", also known as quantum dots, can be loaded with electrons, one-by-one, and subsequently unloaded using source and drain electrical contacts. As such, quantum dots are uniquely tunable platforms for performing quantum transport and quantum control experiments. Voltage-biased electron transport through quantum dots has been studied extensively. Far less attention has been given to thermoelectric effects in quantum dots, that is, electron transport induced by a temperature gradient. This dissertation focuses on the efficiency of direct thermal-to-electric energy conversion in InAs/InP quantum dots embedded in nanowires. The efficiency of thermoelectric heat engines is bounded by the same maximum efficiency as cyclic heat engines; namely, by Carnot efficiency. The efficiency of bulk thermoelectric materials suffers from their inability to transport charge carriers selectively based on energy. Owing to their three-dimensional momentum quantization, quantum dots operate as electron energy filters---a property which can be harnessed to minimize entropy production and therefore maximize efficiency. This research was motivated by the possibility to realize experimentally a thermodynamic heat engine operating with near-Carnot efficiency using the unique behavior of quantum dots. To this end, a microscopic heating scheme for the application of a temperature difference across a quantum dot was developed in conjunction with a novel quantum-dot thermometry technique used for quantifying the magnitude of the applied temperature difference. While pursuing high-efficiency thermoelectric performance, many mesoscopic thermoelectric effects were observed and studied, including Coulomb-blockade thermovoltage oscillations, thermoelectric power generation, and strong nonlinear behavior. In the end, a quantum-dot-based thermoelectric heat engine was achieved and demonstrated an electronic efficiency of up to 95% Carnot efficiency.

Case studies of energy efficiency financing in the original five pilot states, 1993-1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farhar, B C; Collins, N E; Walsh, R W

1997-05-01

The purpose of this report is to document progress in state-level programs in energy efficiency financing programs that are linked with home energy rating systems. Case studies are presented of programs in five states using a federal pilot program to amortize the costs of home energy improvements. The case studies present background information, describe the states` program, list preliminary evaluation data and findings, and discuss problems and solution encountered in the programs. A comparison of experiences in pilot states will be used to provide guidelines for program implementers, federal agencies, and Congress. 5 refs.

Advanced Commercial Buildings Initiative Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, Sydney G.

The Southface Advanced Commercial Buildings Initiative has developed solutions to overcome market barriers to energy reductions in small commercial buildings by building on the success of four local and Southeast regional energy efficiency deployment programs. These programs address a variety of small commercial building types, efficiency levels, owners, facility manager skills and needs for financing. The deployment programs also reach critical private sector, utility, nonprofit and government submarkets, and have strong potential to be replicated at scale. During the grant period, 200 small commercial buildings participated in Southface-sponsored energy upgrade programs, saving 166,736,703 kBtu of source energy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Todt, Michael A.; Isenberg, Allan E.; Nanayakkara, Sanjini U.

Semiconducting transition-metal dichalcogenide (TMD) nanoflake thin films are promising large-area electrodes for photo-electrochemical solar energy conversion applications. However, their energy conversion efficiencies are typically much lower than those of bulk electrodes. It is unclear to what extent this efficiency gap stems from differences among nanoflakes (e.g., area, thickness, and surface structural features). It is also unclear whether individual exfoliated nanoflakes can achieve energy conversion efficiencies similar to those of bulk crystals. Here, we use a single-nanoflake photo-electrochemical approach to show that there are both highly active and completely inactive nanoflakes within a film. For the exfoliated MoSe 2 samples studiedmore » herein, 7% of nanoflakes are highly active champions, whose photocurrent efficiency exceeds that of the bulk crystal. However, 66% of nanoflakes are inactive spectators, which are mostly responsible for the overall lower photocurrent efficiency compared to the bulk crystal. The photocurrent collection efficiency increases with nanoflake area and decreases more at perimeter edges than at interior step edges. These observations, which are hidden in ensemble-level measurements, reveal the underlying performance issues of exfoliated TMD electrodes for photo-electrochemical energy conversion applications.« less

Life cycle assessment for optimising the level of separated collection in integrated MSW management systems.

PubMed

Rigamonti, L; Grosso, M; Giugliano, M

2009-02-01

This life cycle assessment study analyses material and energy recovery within integrated municipal solid waste (MSW) management systems, and, in particular, the recovery of the source-separated materials (packaging and organic waste) and the energy recovery from the residual waste. The recovery of materials and energy are analysed together, with the final aim to evaluate possible optimum levels of source-separated collection that lead to the most favourable energetic and environmental results; this method allows identification of an optimum configuration of the MSW management system. The results show that the optimum level of source-separated collection is about 60%, when all the materials are recovered with high efficiency; it decreases to about 50%, when the 60% level is reached as a result of a very high recovery efficiency for organic fractions at the expense of the packaging materials, or when this implies an appreciable reduction of the quality of collected materials. The optimum MSW management system is thus characterized by source-separated collection levels as included in the above indicated range, with subsequent recycling of the separated materials and energy recovery of the residual waste in a large-scale incinerator operating in combined heat and power mode.

Exploring efficacy of residential energy efficiency programs in Florida

NASA Astrophysics Data System (ADS)

Taylor, Nicholas Wade

Electric utilities, government agencies, and private interests in the U.S. have committed and continue to invest substantial resources in the pursuit of energy efficiency and conservation through demand-side management (DSM) programs. Program investments, and the demand for impact evaluations that accompany them, are projected to grow in coming years due to increased pressure from state-level energy regulation, costs and challenges of building additional production capacity, fuel costs and potential carbon or renewable energy regulation. This dissertation provides detailed analyses of ex-post energy savings from energy efficiency programs in three key sectors of residential buildings: new, single-family, detached homes; retrofits to existing single-family, detached homes; and retrofits to existing multifamily housing units. Each of the energy efficiency programs analyzed resulted in statistically significant energy savings at the full program group level, yet savings for individual participants and participant subgroups were highly variable. Even though savings estimates were statistically greater than zero, those energy savings did not always meet expectations. Results also show that high variability in energy savings among participant groups or subgroups can negatively impact overall program performance and can undermine marketing efforts for future participation. Design, implementation, and continued support of conservation programs based solely on deemed or projected savings is inherently counter to the pursuit of meaningful energy conservation and reductions in greenhouse gas emissions. To fully understand and optimize program impacts, consistent and robust measurement and verification protocols must be instituted in the design phase and maintained over time. Furthermore, marketing for program participation must target those who have the greatest opportunity for savings. In most utility territories it is not possible to gain access to the type of large scale datasets that would facilitate robust program analysis. Along with measuring and optimizing energy conservation programs, utilities should provide public access to historical consumption data. Open access to data, program optimization, consistent measurement and verification and transparency in reported savings are essential to reducing energy use and its associated environmental impacts.

Molecular design of photovoltaic materials for polymer solar cells: toward suitable electronic energy levels and broad absorption.

PubMed

Li, Yongfang

2012-05-15

Bulk heterojunction (BHJ) polymer solar cells (PSCs) sandwich a blend layer of conjugated polymer donor and fullerene derivative acceptor between a transparent ITO positive electrode and a low work function metal negative electrode. In comparison with traditional inorganic semiconductor solar cells, PSCs offer a simpler device structure, easier fabrication, lower cost, and lighter weight, and these structures can be fabricated into flexible devices. But currently the power conversion efficiency (PCE) of the PSCs is not sufficient for future commercialization. The polymer donors and fullerene derivative acceptors are the key photovoltaic materials that will need to be optimized for high-performance PSCs. In this Account, I discuss the basic requirements and scientific issues in the molecular design of high efficiency photovoltaic molecules. I also summarize recent progress in electronic energy level engineering and absorption spectral broadening of the donor and acceptor photovoltaic materials by my research group and others. For high-efficiency conjugated polymer donors, key requirements are a narrower energy bandgap (E(g)) and broad absorption, relatively lower-lying HOMO (the highest occupied molecular orbital) level, and higher hole mobility. There are three strategies to meet these requirements: D-A copolymerization for narrower E(g) and lower-lying HOMO, substitution with electron-withdrawing groups for lower-lying HOMO, and two-dimensional conjugation for broad absorption and higher hole mobility. Moreover, better main chain planarity and less side chain steric hindrance could strengthen π-π stacking and increase hole mobility. Furthermore, the molecular weight of the polymers also influences their photovoltaic performance. To produce high efficiency photovoltaic polymers, researchers should attempt to increase molecular weight while maintaining solubility. High-efficiency D-A copolymers have been obtained by using benzodithiophene (BDT), dithienosilole (DTS), or indacenodithiophene (IDT) donor unit and benzothiadiazole (BT), thienopyrrole-dione (TPD), or thiazolothiazole (TTz) acceptor units. The BDT unit with two thienyl conjugated side chains is a highly promising unit in constructing high-efficiency copolymer donor materials. The electron-withdrawing groups of ester, ketone, fluorine, or sulfonyl can effectively tune the HOMO energy levels downward. To improve the performance of fullerene derivative acceptors, researchers will need to strengthen absorption in the visible spectrum, upshift the LUMO (the lowest unoccupied molecular orbital) energy level, and increase the electron mobility. [6,6]-Phenyl-C(71)-butyric acid methyl ester (PC(70)BM) is superior to [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) because C(70) absorbs visible light more efficiently. Indene-C(60) bisadduct (ICBA) and Indene-C(70) bisadduct (IC(70)BA) show 0.17 and 0.19 eV higher LUMO energy levels, respectively, than PCBM, due to the electron-rich character of indene and the effect of bisadduct. ICBA and IC(70)BA are excellent acceptors for the P3HT-based PSCs.

Dynamics of energy transfer from lycopene to bacteriochlorophyll in genetically-modified LH2 complexes of Rhodobacter sphaeroides.

PubMed

Hörvin Billsten, H; Herek, J L; Garcia-Asua, G; Hashøj, L; Polívka, T; Hunter, C N; Sundström, V

2002-03-26

LH2 complexes from Rb. sphaeroides were modified genetically so that lycopene, with 11 saturated double bonds, replaced the native carotenoids which contain 10 saturated double bonds. Tuning the S1 level of the carotenoid in LH2 in this way affected the dynamics of energy transfer within LH2, which were investigated using both steady-state and time-resolved techniques. The S1 energy of lycopene in n-hexane was determined to be approximately 12 500 +/- 150 cm(-1), by direct measurement of the S1-S2 transient absorption spectrum using a femtosecond IR-probing technique, thus placing an upper limit on the S1 energy of lycopene in the LH2 complex. Fluorescence emission and excitation spectra demonstrated that energy can be transferred from lycopene to the bacteriochlorophyll molecules within this LH2 complex. The energy-transfer dynamics within the mutant complex were compared to wild-type LH2 from Rb. sphaeroides containing the carotenoid spheroidene and from Rs. molischianum, in which lycopene is the native carotenoid. The results show that the overall efficiency for Crt --> B850 energy transfer is approximately 80% in lyco-LH2 and approximately 95% in WT-LH2 of Rb. sphaeroides. The difference in overall Crt --> BChl transfer efficiency of lyco-LH2 and WT-LH2 mainly relates to the low efficiency of the Crt S(1) --> BChl pathway for complexes containing lycopene, which was 20% in lyco-LH2. These results show that in an LH2 complex where the Crt S1 energy is sufficiently high to provide efficient spectral overlap with both B800 and B850 Q(y) states, energy transfer via the Crt S1 state occurs to both pigments. However, the introduction of lycopene into the Rb. sphaeroides LH2 complex lowers the S1 level of the carotenoid sufficiently to prevent efficient transfer of energy to the B800 Q(y) state, leaving only the Crt S1 --> B850 channel, strongly suggesting that Crt S1 --> BChl energy transfer is controlled by the relative Crt S1 and BChl Q(y) energies.

Coupled-Double-Quantum-Dot Environmental Information Engines: A Numerical Analysis

NASA Astrophysics Data System (ADS)

Tanabe, Katsuaki

2016-06-01

We conduct numerical simulations for an autonomous information engine comprising a set of coupled double quantum dots using a simple model. The steady-state entropy production rate in each component, heat and electron transfer rates are calculated via the probability distribution of the four electronic states from the master transition-rate equations. We define an information-engine efficiency based on the entropy change of the reservoir, implicating power generators that employ the environmental order as a new energy resource. We acquire device-design principles, toward the realization of corresponding practical energy converters, including that (1) higher energy levels of the detector-side reservoir than those of the detector dot provide significantly higher work production rates by faster states' circulation, (2) the efficiency is strongly dependent on the relative temperatures of the detector and system sides and becomes high in a particular Coulomb-interaction strength region between the quantum dots, and (3) the efficiency depends little on the system dot's energy level relative to its reservoir but largely on the antisymmetric relative amplitudes of the electronic tunneling rates.

Polaron effects on the performance of light-harvesting systems: a quantum heat engine perspective

NASA Astrophysics Data System (ADS)

Xu, Dazhi; Wang, Chen; Zhao, Yang; Cao, Jianshu

2016-02-01

We explore energy transfer in a generic three-level system, which is coupled to three non-equilibrium baths. Built on the concept of quantum heat engine, our three-level model describes non-equilibrium quantum processes including light-harvesting energy transfer, nano-scale heat transfer, photo-induced isomerization, and photovoltaics in double quantum-dots. In the context of light-harvesting, the excitation energy is first pumped up by sunlight, then is transferred via two excited states which are coupled to a phonon bath, and finally decays to the reaction center. The efficiency of this process is evaluated by steady state analysis via a polaron-transformed master equation; thus the entire range of the system-phonon coupling strength can be covered. We show that the coupling with the phonon bath not only modifies the steady state, resulting in population inversion, but also introduces a finite steady state coherence which optimizes the energy transfer flux and efficiency. In the strong coupling limit, the steady state coherence disappears and the efficiency recovers the heat engine limit given by Scovil and Schultz-Dubois (1959 Phys. Rev. Lett. 2 262).

TV Energy Consumption Trends and Energy-Efficiency Improvement Options

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Won Young; Phadke, Amol; Shah, Nihar

2011-07-01

The SEAD initiative aims to transform the global market by increasing the penetration of highly efficient equipment and appliances. SEAD is a government initiative whose activities and projects engage the private sector to realize the large global energy savings potential from improved appliance and equipment efficiency. SEAD seeks to enable high-level global action by informing the Clean Energy Ministerial dialogue as one of the initiatives in the Global Energy Efficiency Challenge. In keeping with its goal of achieving global energy savings through efficiency, SEAD was approved as a task within the International Partnership for Energy Efficiency Cooperation (IPEEC) in Januarymore » 2010. SEAD partners work together in voluntary activities to: (1) ?raise the efficiency ceiling? by pulling super-efficient appliances and equipment into the market through cooperation on measures like incentives, procurement, awards, and research and development (R&D) investments; (2) ?raise the efficiency floor? by working together to bolster national or regional policies like minimum efficiency standards; and (3) ?strengthen the efficiency foundations? of programs by coordinating technical work to support these activities. Although not all SEAD partners may decide to participate in every SEAD activity, SEAD partners have agreed to engage actively in their particular areas of interest through commitment of financing, staff, consultant experts, and other resources. In addition, all SEAD partners are committed to share information, e.g., on implementation schedules for and the technical detail of minimum efficiency standards and other efficiency programs. Information collected and created through SEAD activities will be shared among all SEAD partners and, to the extent appropriate, with the global public.As of April 2011, the governments participating in SEAD are: Australia, Brazil, Canada, the European Commission, France, Germany, India, Japan, Korea, Mexico, Russia, South Africa, Sweden, the United Arab Emirates, the United Kingdom, and the United States. More information on SEAD is available from its website at http://www.superefficient.org/.« less

The performance of the jet trigger for the ATLAS detector during 2011 data taking

NASA Astrophysics Data System (ADS)

Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Gonzalez, B. Alvarez; Piqueras, D. Álvarez; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Navarro, L. Barranco; Barreiro, F.; da Costa, J. Barreiro Guimarães; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Benitez, J.; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Berghaus, F.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bylund, O. Bessidskaia; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Bortfeldt, J.; Bortoletto, D.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Sola, J. D. Bossio; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Madden, W. D. Breaden; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Broughton, J. H.; de Renstrom, P. A. Bruckman; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Brunt, BH; Bruschi, M.; Bruscino, N.; Bryant, P.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Budagov, I. A.; Buehrer, F.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burghgrave, B.; Burka, K.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Urbán, S. Cabrera; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Calvet, T. P.; Toro, R. Camacho; Camarda, S.; Camarri, P.; Cameron, D.; Armadans, R. Caminal; Camincher, C.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Bret, M. Cano; Cantero, J.; Cantrill, R.; Cao, T.; Garrido, M. D. M. Capeans; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, I.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Casper, D. 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C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Santurio, E. Valdes; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Vallecorsa, S.; Ferrer, J. A. Valls; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vazeille, F.; Schroeder, T. Vazquez; Veatch, J.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Boeriu, O. E. Vickey; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Vigne, R.; Villa, M.; Perez, M. Villaplana; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Milosavljevic, M. Vranjes; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Wong, K. H. Yau; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Nedden, M. zur; Zurzolo, G.; Zwalinski, L.

2016-10-01

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton-proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon-nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction.

Reduced energy offset via substitutional doping for efficient organic/inorganic hybrid solar cells.

PubMed

Jin, Xiao; Sun, Weifu; Zhang, Qin; Ruan, Kelian; Cheng, Yuanyuan; Xu, Haijiao; Xu, Zhongyuan; Li, Qinghua

2015-06-01

Charge carrier transport in bulk heterojunction that is central to the device performance of solar cells is sensitively dependent on the energy level alignment of acceptor and donor. However, the effect of energy level regulation induced by nickel ions on the primary photoexcited electron transfer and the performance of P3HT/TiO₂ hybrid solar cells remains being poorly understood and rarely studied. Here we demonstrate that the introduction of the versatile nickel ions into TiO₂ nanocrystals can significantly elevate the conduction and valence band energy levels of the acceptor, thus resulting in a remarkable reduction of energy level offset between the conduction band of acceptor and lowest unoccupied molecular orbital of donor. By applying transient photoluminescence and femtosecond transient absorption spectroscopies, we demonstrate that the electron transfer becomes more competitive after incorporating nickel ions. In particular, the electron transfer life time is shortened from 30.2 to 16.7 ps, i.e., more than 44% faster than pure TiO₂ acceptor, thus leading to a notable increase of power conversion efficiency in organic/inorganic hybrid solar cells. This work underscores the promising virtue of engineering the reduction of 'excess' energy offset to accelerate electron transport and demonstrates the potential of nickel ions in applications of solar energy conversion and photon detectors.

Diode-laser pumping into the emitting level for efficient lasing of depressed cladding waveguides realized in Nd:YVO4 by the direct femtosecond-laser writing technique.

PubMed

Pavel, Nicolaie; Salamu, Gabriela; Jipa, Florin; Zamfirescu, Marian

2014-09-22

Depressed cladding waveguides have been realized in Nd:YVO(4) employing direct writing technique with a femtosecond-laser beam. It was shown that the output performances of such laser devices are improved by the reduction of the quantum defect between the pump wavelength and the laser wavelength. Thus, under the classical pump at 808 nm (i.e. into the (4)F(5/2) level), a 100-μm diameter circular waveguide inscribed in a 0.7-at.% Nd:YVO(4) outputted 1.06-μm laser pulses with 3.0-mJ energy, at 0.30 optical efficiency and slope efficiency of 0.32. The pump at 880 nm (i.e.directly into the (4)F(3/2) emitting level) increased the pulse energy at 3.8 mJ and improved both optical efficiency and slope efficiency at 0.36 and 0.39, respectively. The same waveguide yielded continuous-wave 1.5-W output power at 1.06 μm under the pump at 880 nm. Laser emission at 1.34 μm was also improved using the pump into the (4)F(3/2) emitting level of Nd:YVO(4).

77 FR 28927 - Energy Conservation Program for Certain Industrial Equipment: Energy Conservation Standards and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-16

...The U.S. Department of Energy (DOE) is amending its energy conservation standards for small, large, and very large water-cooled and evaporatively-cooled commercial package air conditioners, and variable refrigerant flow (VRF) water-source heat pumps less than 17,000 Btu/h. DOE is adopting new energy conservation standards for computer room air conditioners and VRF water-source heat pumps with a cooling capacity at or greater than 135,000 Btu/h and less than 760,000 Btu/h. Pursuant to the Energy Policy and Conservation Act of 1975 (EPCA), as amended, DOE must assess whether the uniform national standards for these covered equipment need to be updated each time the corresponding industry standard--the American National Standards Institute (ANSI)/American Society of Heating, Refrigerating, and Air- Conditioning Engineers (ASHRAE)/Illuminating Engineering Society of North America (IESNA) Standard 90.1 (ASHRAE Standard 90.1)--is amended, which most recently occurred on October 29, 2010. The levels DOE is adopting are the same as the efficiency levels specified in ASHRAE Standard 90.1-2010. DOE has determined that the ASHRAE Standard 90.1- 2010 efficiency levels for the equipment types listed above are more stringent than existing Federal energy conservation standards and will result in economic and energy savings compared existing energy conservation standards. Furthermore, DOE has concluded that clear and convincing evidence does not exist, as would justify more-stringent standard levels than the efficiency levels in ASHRAE Standard 90.1-2010 for any of the equipment classes. DOE is also updating the current Federal test procedures or, for certain equipment, adopting new test procedures to incorporate by reference the most current versions of the relevant industry test procedures specified in ASHRAE Standard 90.1- 2010. Furthermore, DOE is adopting additional test procedure provisions to include with modification certain instructions from Air- Conditioning, Heating, and Refrigeration Institute (AHRI) operations manuals in that organization's test procedures that would clarify the application of the DOE test procedures and harmonize DOE testing with the testing performed by industry.

Selectively Modulating Triplet Exciton Formation in Host Materials for Highly Efficient Blue Electrophosphorescence.

PubMed

Li, Huanhuan; Bi, Ran; Chen, Ting; Yuan, Kai; Chen, Runfeng; Tao, Ye; Zhang, Hongmei; Zheng, Chao; Huang, Wei

2016-03-23

The concept of limiting the triplet exciton formation to fundamentally alleviate triplet-involved quenching effects is introduced to construct host materials for highly efficient and stable blue phosphorescent organic light-emitting diodes (PhOLEDs). The low triplet exciton formation is realized by small triplet exciton formation fraction and rate with high binding energy and high reorganization energy of triplet exciton. Demonstrated in two analogue molecules in conventional donor-acceptor molecule structure for bipolar charge injection and transport with nearly the same frontier orbital energy levels and triplet excited energies, the new concept host material shows significantly suppressed triplet exciton formation in the host to avoid quenching effects, leading to much improved device efficiencies and stabilities. The low-voltage-driving blue PhOLED devices exhibit maximum efficiencies of 43.7 cd A(-1) for current efficiency, 32.7 lm W(-1) for power efficiency, and 20.7% for external quantum efficiency with low roll-off and remarkable relative quenching effect reduction ratio up to 41%. Our fundamental solution for preventing quenching effects of long-lived triplet excitons provides exciting opportunities for fabricating high-performance devices using the advanced host materials with intrinsically small triplet exciton formation cross section.

Energy-Efficient Control with Harvesting Predictions for Solar-Powered Wireless Sensor Networks.

PubMed

Zou, Tengyue; Lin, Shouying; Feng, Qijie; Chen, Yanlian

2016-01-04

Wireless sensor networks equipped with rechargeable batteries are useful for outdoor environmental monitoring. However, the severe energy constraints of the sensor nodes present major challenges for long-term applications. To achieve sustainability, solar cells can be used to acquire energy from the environment. Unfortunately, the energy supplied by the harvesting system is generally intermittent and considerably influenced by the weather. To improve the energy efficiency and extend the lifetime of the networks, we propose algorithms for harvested energy prediction using environmental shadow detection. Thus, the sensor nodes can adjust their scheduling plans accordingly to best suit their energy production and residual battery levels. Furthermore, we introduce clustering and routing selection methods to optimize the data transmission, and a Bayesian network is used for warning notifications of bottlenecks along the path. The entire system is implemented on a real-time Texas Instruments CC2530 embedded platform, and the experimental results indicate that these mechanisms sustain the networks' activities in an uninterrupted and efficient manner.

Energy-Efficient Control with Harvesting Predictions for Solar-Powered Wireless Sensor Networks

PubMed Central

Zou, Tengyue; Lin, Shouying; Feng, Qijie; Chen, Yanlian

2016-01-01

Wireless sensor networks equipped with rechargeable batteries are useful for outdoor environmental monitoring. However, the severe energy constraints of the sensor nodes present major challenges for long-term applications. To achieve sustainability, solar cells can be used to acquire energy from the environment. Unfortunately, the energy supplied by the harvesting system is generally intermittent and considerably influenced by the weather. To improve the energy efficiency and extend the lifetime of the networks, we propose algorithms for harvested energy prediction using environmental shadow detection. Thus, the sensor nodes can adjust their scheduling plans accordingly to best suit their energy production and residual battery levels. Furthermore, we introduce clustering and routing selection methods to optimize the data transmission, and a Bayesian network is used for warning notifications of bottlenecks along the path. The entire system is implemented on a real-time Texas Instruments CC2530 embedded platform, and the experimental results indicate that these mechanisms sustain the networks’ activities in an uninterrupted and efficient manner. PMID:26742042

An Energy Balanced and Lifetime Extended Routing Protocol for Underwater Sensor Networks.

PubMed

Wang, Hao; Wang, Shilian; Zhang, Eryang; Lu, Luxi

2018-05-17

Energy limitation is an adverse problem in designing routing protocols for underwater sensor networks (UWSNs). To prolong the network lifetime with limited battery power, an energy balanced and efficient routing protocol, called energy balanced and lifetime extended routing protocol (EBLE), is proposed in this paper. The proposed EBLE not only balances traffic loads according to the residual energy, but also optimizes data transmissions by selecting low-cost paths. Two phases are operated in the EBLE data transmission process: (1) candidate forwarding set selection phase and (2) data transmission phase. In candidate forwarding set selection phase, nodes update candidate forwarding nodes by broadcasting the position and residual energy level information. The cost value of available nodes is calculated and stored in each sensor node. Then in data transmission phase, high residual energy and relatively low-cost paths are selected based on the cost function and residual energy level information. We also introduce detailed analysis of optimal energy consumption in UWSNs. Numerical simulation results on a variety of node distributions and data load distributions prove that EBLE outperforms other routing protocols (BTM, BEAR and direct transmission) in terms of network lifetime and energy efficiency.

Energy efficient engine: Turbine intermediate case and low-pressure turbine component test hardware detailed design report

NASA Technical Reports Server (NTRS)

Leach, K.; Thulin, R. D.; Howe, D. C.

1982-01-01

A four stage, low pressure turbine component has been designed to power the fan and low pressure compressor system in the Energy Efficient Engine. Designs for a turbine intermediate case and an exit guide vane assembly also have been established. The components incorporate numerous technology features to enhance efficiency, durability, and performance retention. These designs reflect a positive step towards improving engine fuel efficiency on a component level. The aerodynamic and thermal/mechanical designs of the intermediate case and low pressure turbine components are presented and described. An overview of the predicted performance of the various component designs is given.

78 FR 37995 - Energy Efficiency Standards for Manufactured Housing

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-25

... address the relationship between potential reductions in levels of natural air infiltration and both... typical baseline levels of air infiltration through recently-built manufactured homes and information on...

Frontiers of controlling energy levels at interfaces

NASA Astrophysics Data System (ADS)

Koch, Norbert

The alignment of electron energy levels at interfaces between semiconductors, dielectrics, and electrodes determines the function and efficiency of all electronic and optoelectronic devices. Reliable guidelines for predicting the level alignment for a given material combination and methods to adjust the intrinsic energy landscape are needed to enable efficient engineering approaches. These are sufficiently understood for established electronic materials, e.g., Si, but for the increasing number of emerging materials, e.g., organic and 2D semiconductors, perovskites, this is work in progress. The intrinsic level alignment and the underlying mechanisms at interfaces between organic and inorganic semiconductors are discussed first. Next, methods to alter the level alignment are introduced, which all base on proper charge density rearrangement at a heterojunction. As interface modification agents we use molecular electron acceptors and donors, as well as molecular photochromic switches that add a dynamic aspect and allow device multifunctionality. For 2D semiconductors surface transfer doping with molecular acceptors/donors transpires as viable method to locally tune the Fermi-level position in the energy gap. The fundamental electronic properties of a prototypical 1D interface between intrinsic and p-doped 2D semiconductor regions are derived from local (scanning probe) and area-averaged (photoemission) spectroscopy experiments. Future research opportunities for attaining unsurpassed interface control through charge density management are discussed.

Triplet exciton confinement for enhanced fluorescent organic light-emitting diodes using a co-host system

NASA Astrophysics Data System (ADS)

Yoo, Han Kyu; Lee, Ho Won; Lee, Song Eun; Kim, Young Kwan; Kim, Se Hyun; Yoon, Seung Soo; Park, Jaehoon

2016-05-01

In this work, the co-host system within an emitting layer (EML) consists of the host and triplet managing (TM) host materials. A set of EML structures was fabricated with various concentrations of the TM host (0, 10, 30, 50, and 70%). The TM host triplet energy level is lower than the energy levels of the host and the guest, which leads to a reduction in the triplet exciton density and the singlet-triplet annihilation of the guest. Blue fluorescent organic light-emitting diodes exhibit a maximum luminous efficiency (LE) and an external quantum efficiency (EQE) of 9.74 cd/A and 4.92%, respectively. In addition, the efficiency roll-off ratios of the LE and the EQE are 14.25 and 13.16%, respectively.

Energy Efficiency Improvement and Cost Saving Opportunities for the Dairy Processing Industry: An ENERGY STAR? Guide for Energy and Plant Managers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brush, Adrian; Masanet, Eric; Worrell, Ernst

The U.S. dairy processing industry—defined in this Energy Guide as facilities engaged in the conversion of raw milk to consumable dairy products—consumes around $1.5 billion worth of purchased fuels and electricity per year. Energy efficiency improvement is an important way to reduce these costs and to increase predictable earnings, especially in times of high energy price volatility. There are a variety of opportunities available at individual plants in the U.S. dairy processing industry to reduce energy consumption and greenhouse gas emissions in a cost-effective manner. This Energy Guide discusses energy efficiency practices and energy-efficient technologies that can be implemented atmore » the component, process, facility, and organizational levels. A discussion of the trends, structure, and energy consumption characteristics of the U.S. dairy processing industry is provided along with a description of the major process technologies used within the industry. Next, a wide variety of energy efficiency measures applicable to dairy processing plants are described. Many measure descriptions include expected savings in energy and energy-related costs, based on case study data from real-world applications in dairy processing facilities and related industries worldwide. Typical measure payback periods and references to further information in the technical literature are also provided, when available. Given the importance of water in dairy processing, a summary of basic, proven measures for improving water efficiency are also provided. The information in this Energy Guide is intended to help energy and plant managers in the U.S. dairy processing industry reduce energy and water consumption in a cost-effective manner while maintaining the quality of products manufactured. Further research on the economics of all measures—as well as on their applicability to different production practices—is needed to assess their cost effectiveness at individual plants.« less

Fayette County Better Buildings Initiative

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capella, Arthur

The Fayette County Better Buildings Initiative represented a comprehensive and collaborative approach to promoting and implementing energy efficiency improvements. The initiative was designed to focus on implementing energy efficiency improvements in residential units, while simultaneously supporting general marketing of the benefits of implementing energy efficiency measures. The ultimate goal of Fayette County’s Better Buildings Initiative was to implement a total of 1,067 residential energy efficiency retrofits with a minimum 15% estimated energy efficiency savings per unit. Program partners included: United States Department of Energy, Allegheny Power, and Private Industry Council of Westmoreland-Fayette, Fayette County Redevelopment Authority, and various local partners.more » The program was open to any Fayette County residents who own their home and meet the prequalifying conditions. The level of assistance offered depended upon household income and commitment to undergo a BPI – Certified Audit and implement energy efficiency measures, which aimed to result in at least a 15% reduction in energy usage. The initiative was designed to focus on implementing energy efficiency improvements in residential units, while simultaneously supporting general marketing of the benefits of implementing energy efficiency measures. Additionally, the program had components that involved recruitment and training for employment of persons in the energy sector (green jobs), as well as marketing and implementation of a commercial or community facilities component. The residential component of Fayette County’s Better Buildings Initiative involved a comprehensive approach, providing assistance to low- moderate- and market-rate homeowners. The initiative will also coordinate activities with local utility providers to further incentivize energy efficiency improvements among qualifying homeowners. The commercial component of Fayette County’s Better Building Initiative involved grants and loans to assist up to $15,000 projects per commercial structure with a mixture of a grant and financing at 0% for up to three – (3) years. The maximum award can be a $5,000 grant and a $10,000 loan. For projects less than $15,000, the award will have a ratio of 1/3 grant and 2/3 loan.« less

Walking model with no energy cost.

PubMed

Gomes, Mario; Ruina, Andy

2011-03-01

We have numerically found periodic collisionless motions of a walking model consisting of linked rigid objects. Unlike previous designs, this model can walk on level ground at noninfinitesimal speed with zero energy input. The model avoids collisional losses by using an internal mode of oscillation: swaying of the upper body coupled to the legs by springs. Appropriate synchronized internal oscillations set the foot-strike collision to zero velocity. The concept might be of use for energy-efficient robots and may also help to explain aspects of human and animal locomotion efficiency.

Pump efficiency in solar-energy systems

NASA Technical Reports Server (NTRS)

1978-01-01

Study investigates characteristics of typical off-the-shelf pumping systems that might be used in solar systems. Report includes discussion of difficulties in predicting pump efficiency from manufacturers' data. Sample calculations are given. Peak efficiencies, flow-rate control, and noise levels are investigated. Review or theory of pumps types and operating characteristics is presented.

Cross-layer cluster-based energy-efficient protocol for wireless sensor networks.

PubMed

Mammu, Aboobeker Sidhik Koyamparambil; Hernandez-Jayo, Unai; Sainz, Nekane; de la Iglesia, Idoia

2015-04-09

Recent developments in electronics and wireless communications have enabled the improvement of low-power and low-cost wireless sensors networks (WSNs). One of the most important challenges in WSNs is to increase the network lifetime due to the limited energy capacity of the network nodes. Another major challenge in WSNs is the hot spots that emerge as locations under heavy traffic load. Nodes in such areas quickly drain energy resources, leading to disconnection in network services. In such an environment, cross-layer cluster-based energy-efficient algorithms (CCBE) can prolong the network lifetime and energy efficiency. CCBE is based on clustering the nodes to different hexagonal structures. A hexagonal cluster consists of cluster members (CMs) and a cluster head (CH). The CHs are selected from the CMs based on nodes near the optimal CH distance and the residual energy of the nodes. Additionally, the optimal CH distance that links to optimal energy consumption is derived. To balance the energy consumption and the traffic load in the network, the CHs are rotated among all CMs. In WSNs, energy is mostly consumed during transmission and reception. Transmission collisions can further decrease the energy efficiency. These collisions can be avoided by using a contention-free protocol during the transmission period. Additionally, the CH allocates slots to the CMs based on their residual energy to increase sleep time. Furthermore, the energy consumption of CH can be further reduced by data aggregation. In this paper, we propose a data aggregation level based on the residual energy of CH and a cost-aware decision scheme for the fusion of data. Performance results show that the CCBE scheme performs better in terms of network lifetime, energy consumption and throughput compared to low-energy adaptive clustering hierarchy (LEACH) and hybrid energy-efficient distributed clustering (HEED).

Reaction wheels for kinetic energy storage

NASA Astrophysics Data System (ADS)

Studer, P. A.

1984-11-01

In contrast to all existing reaction wheel implementations, an order of magnitude increase in speed can be obtained efficiently if power to the actuators can be recovered. This allows a combined attitude control-energy storage system to be developed with structure mounted reaction wheels. The feasibility of combining reaction wheels with energy storage wwheels is demonstrated. The power required for control torques is a function of wheel speed but this energy is not dissipated; it is stored in the wheel. The I(2)R loss resulting from a given torque is shown to be constant, independent of the design speed of the motor. What remains, in order to efficiently use high speed wheels (essential for energy storage) for control purposes, is to reduce rotational losses to acceptable levels. Progress was made in permanent magnet motor design for high speed operation. Variable field motors offer more control flexibility and efficiency over a broader speed range.

Reaction wheels for kinetic energy storage

NASA Technical Reports Server (NTRS)

Studer, P. A.

1984-01-01

In contrast to all existing reaction wheel implementations, an order of magnitude increase in speed can be obtained efficiently if power to the actuators can be recovered. This allows a combined attitude control-energy storage system to be developed with structure mounted reaction wheels. The feasibility of combining reaction wheels with energy storage wwheels is demonstrated. The power required for control torques is a function of wheel speed but this energy is not dissipated; it is stored in the wheel. The I(2)R loss resulting from a given torque is shown to be constant, independent of the design speed of the motor. What remains, in order to efficiently use high speed wheels (essential for energy storage) for control purposes, is to reduce rotational losses to acceptable levels. Progress was made in permanent magnet motor design for high speed operation. Variable field motors offer more control flexibility and efficiency over a broader speed range.

Intermediate photovoltaic system application experiment operational performance report. Volume 6: Beverly High School, Beverly, Mass.

NASA Astrophysics Data System (ADS)

1982-03-01

Performance data are given for the month of February, 1982 for a photovoltaic power supply at a Massachusetts high school. Data given include: monthly and daily electrical energy yield; monthly and daily insolation; monthly and daily array efficiency; energy production as a function of power level, voltage, cell temperature, and hour of day; insolation as a function of hour of the day; input, output and efficiency for each of two power conditioning units and for the total power conditioning system; energy supplied to the load by the photovoltaic system and by the grid; photovoltaic system efficiency; dollar value of the energy supplied by the photovoltaic system; capacity factor; daily photovoltaic energy to load; daily system availability and hours of daylight; heating and cooling degree days; hourly cell temperature, ambient temperature, wind speed, and insolation; average monthly wind speed; wind direction distribution; and daily data acquisition mode and recording interval plot.

Intermediate photovoltaic system application experiment operational performance report: Volume 5, for Beverly High School, Beverly, Mass.

NASA Astrophysics Data System (ADS)

1982-02-01

Performance data for the month of January, 1982 for a grid connected photovoltaic power supply in Massachusetts are presented. Data include: monthly and daily electrical energy produced; monthly and daily solar energy incident on the array; monthly and daily array efficiency; plots of energy produced as a function of power level, voltage, cell temperature and time of day; power conditioner input, output and efficiency for each of two individual units and for the total power conditioning system; photovoltaic system efficiency; capacity factor; PV system to load and grid to load energies and corresponding dollar values; daily energy supplies to the load by the PV system; daily PV system availability; monthly and hourly insolation; monthly and hourly temperature average; monthly and hourly wind speed; wind direction distribution; average heating and cooling degree days; number of freeze/thaw cycles; and the data acquisition mode and recording interval plot.

Resonant energy transfer and trace-level sensing using branched Ag-rod-supported carbon dots

NASA Astrophysics Data System (ADS)

Nair, Radhika V.; Arya, M.; Vijayan, C.

2018-05-01

We report on the resonant energy transfer in branched Ag rod-supported carbon dots (C-dots) and its applications for the trace-level sensing of highly reactive oxygen species and organic pollutants based on surface plasmon enhanced energy transfer (SPEET) and surface enhanced Raman spectroscopy (SERS). The branched morphology of Ag is found to significantly enhance visible light absorption and thus increases the spectral overlap with C-dot emission. In addition, branched morphology results in the formation of a large number of plasmonic hotspots and efficient propagation of plasmons through the interconnections, as also supported by finite-difference time-domain simulations. Branched Ag-rod—C-dot composite is found to be able to detect 0.02 µM of hydrogen peroxide based on SPEET. The efficient transfer of electrons from C-dots to the Ag rod enhances the SERS efficiency of Ag resulting in an enhancement factor of the order of 108 and enables the composite to detect 10‑10 M of the organic pollutant Rhodamine 6G.

Analytical energy gradient based on spin-free infinite-order Douglas-Kroll-Hess method with local unitary transformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakajima, Yuya; Seino, Junji; Nakai, Hiromi, E-mail: nakai@waseda.jp

In this study, the analytical energy gradient for the spin-free infinite-order Douglas-Kroll-Hess (IODKH) method at the levels of the Hartree-Fock (HF), density functional theory (DFT), and second-order Møller-Plesset perturbation theory (MP2) is developed. Furthermore, adopting the local unitary transformation (LUT) scheme for the IODKH method improves the efficiency in computation of the analytical energy gradient. Numerical assessments of the present gradient method are performed at the HF, DFT, and MP2 levels for the IODKH with and without the LUT scheme. The accuracies are examined for diatomic molecules such as hydrogen halides, halogen dimers, coinage metal (Cu, Ag, and Au) halides,more » and coinage metal dimers, and 20 metal complexes, including the fourth–sixth row transition metals. In addition, the efficiencies are investigated for one-, two-, and three-dimensional silver clusters. The numerical results confirm the accuracy and efficiency of the present method.« less

Building Energy Efficiency in Rural China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Meredydd; Yu, Sha; Song, Bo

2014-04-01

Rural buildings in China now account for more than half of China’s total building energy use. Forty percent of the floorspace in China is in rural villages and towns. Most of these buildings are very energy inefficient, and may struggle to meet basic needs. They are cold in the winter, and often experience indoor air pollution from fuel use. The Chinese government plans to adopt a voluntary building energy code, or design standard, for rural homes. The goal is to build on China’s success with codes in urban areas to improve efficiency and comfort in rural homes. The Chinese governmentmore » recognizes rural buildings represent a major opportunity for improving national building energy efficiency. The challenges of rural China are also greater than those of urban areas in many ways because of the limited local capacity and low income levels. The Chinese government wants to expand on new programs to subsidize energy efficiency improvements in rural homes to build capacity for larger-scale improvement. This article summarizes the trends and status of rural building energy use in China. It then provides an overview of the new rural building design standard, and describes options and issues to move forward with implementation.« less

Roadmap of retail electricity market reform in China: assisting in mitigating wind energy curtailment

NASA Astrophysics Data System (ADS)

Yu, Dezhao; Qiu, Huadong; Yuan, Xiang; Li, Yuan; Shao, Changzheng; Lin, You; Ding, Yi

2017-01-01

Among the renewable energies, wind energy has gained the rapidest development in China. Moreover wind power generation has been penetrated into power system in a large scale. However, the high level wind curtailment also indicates a low efficiency of wind energy utilization over the last decade in China. One of the primary constraints on the utilization of wind energy is the lack of an electricity market, in which renewable energies can compete equally with traditional fossil fuel generation. Thus the new round electric power industry reform is essential in China. The reform involves implementing new pricing mechanism, introducing retail-side competition, promoting the consumption of renewable energy. The new round reform can be a promising solution for promoting the development and consumption of wind energy generation in China. Based on proposed reform policies of electric power industry, this paper suggests a roadmap for retail electricity market reform of China, which consists of three stages. Barriers to the efficient utilization of wind energy are also analysed. Finally, this paper introduces several efficient measures for mitigating wind curtailment in each stage of reform.

Radiation efficiency of earthquake sources at different hierarchical levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocharyan, G. G., E-mail: gevorgkidg@mail.ru; Moscow Institute of Physics and Technology

Such factors as earthquake size and its mechanism define common trends in alteration of radiation efficiency. The macroscopic parameter that controls the efficiency of a seismic source is stiffness of fault or fracture. The regularities of this parameter alteration with scale define several hierarchical levels, within which earthquake characteristics obey different laws. Small variations of physical and mechanical properties of the fault principal slip zone can lead to dramatic differences both in the amplitude of released stress and in the amount of radiated energy.

Electrical Matching at Metal/Molecule Contacts for Efficient Heterogeneous Charge Transfer.

PubMed

Sato, Shino; Iwase, Shigeru; Namba, Kotaro; Ono, Tomoya; Hara, Kenji; Fukuoka, Atsushi; Uosaki, Kohei; Ikeda, Katsuyoshi

2018-02-27

In a metal/molecule hybrid system, unavoidable electrical mismatch exists between metal continuum states and frontier molecular orbitals. This causes energy loss in the electron conduction across the metal/molecule interface. For efficient use of energy in a metal/molecule hybrid system, it is necessary to control interfacial electronic structures. Here we demonstrate that electrical matching between a gold substrate and π-conjugated molecular wires can be obtained by using monatomic foreign metal interlayers, which can change the degree of d-π* back-donation at metal/anchor contacts. This interfacial control leads to energy level alignment between the Fermi level of the metal electrode and conduction molecular orbitals, resulting in resonant electron conduction in the metal/molecule hybrid system. When this method is applied to molecule-modified electrocatalysts, the heterogeneous electrochemical reaction rate is considerably improved with significant suppression of energy loss at the internal electron conduction.

Energy Use and Power Levels in New Monitors and Personal Computers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberson, Judy A.; Homan, Gregory K.; Mahajan, Akshay

2002-07-23

Our research was conducted in support of the EPA ENERGY STAR Office Equipment program, whose goal is to reduce the amount of electricity consumed by office equipment in the U.S. The most energy-efficient models in each office equipment category are eligible for the ENERGY STAR label, which consumers can use to identify and select efficient products. As the efficiency of each category improves over time, the ENERGY STAR criteria need to be revised accordingly. The purpose of this study was to provide reliable data on the energy consumption of the newest personal computers and monitors that the EPA can usemore » to evaluate revisions to current ENERGY STAR criteria as well as to improve the accuracy of ENERGY STAR program savings estimates. We report the results of measuring the power consumption and power management capabilities of a sample of new monitors and computers. These results will be used to improve estimates of program energy savings and carbon emission reductions, and to inform rev isions of the ENERGY STAR criteria for these products. Our sample consists of 35 monitors and 26 computers manufactured between July 2000 and October 2001; it includes cathode ray tube (CRT) and liquid crystal display (LCD) monitors, Macintosh and Intel-architecture computers, desktop and laptop computers, and integrated computer systems, in which power consumption of the computer and monitor cannot be measured separately. For each machine we measured power consumption when off, on, and in each low-power level. We identify trends in and opportunities to reduce power consumption in new personal computers and monitors. Our results include a trend among monitor manufacturers to provide a single very low low-power level, well below the current ENERGY STAR criteria for sleep power consumption. These very low sleep power results mean that energy consumed when monitors are off or in active use has become more important in terms of contribution to the overall unit energy consumption (UEC). Cur rent ENERGY STAR monitor and computer criteria do not specify off or on power, but our results suggest opportunities for saving energy in these modes. Also, significant differences between CRT and LCD technology, and between field-measured and manufacturer-reported power levels reveal the need for standard methods and metrics for measuring and comparing monitor power consumption.« less

Factors affecting energy and nitrogen efficiency of dairy cows: a meta-analysis.

PubMed

Phuong, H N; Friggens, N C; de Boer, I J M; Schmidely, P

2013-01-01

A meta-analysis was performed to explore the correlation between energy and nitrogen efficiency of dairy cows, and to study nutritional and animal factors that influence these efficiencies, as well as their relationship. Treatment mean values were extracted from 68 peer-reviewed studies, including 306 feeding trials. The main criterion for inclusion of a study in the meta-analysis was that it reported, or permitted calculation of, energy efficiency (Eeff; energy in milk/digestible energy intake) and nitrogen efficiency (Neff; nitrogen in milk/digestible nitrogen intake) at the digestible level (digestible energy or digestible protein). The effect of nutritional and animal variables, including neutral detergent fiber, acid detergent fiber (ADF), digestible energy, digestible protein, proportion of concentrate (PCO), dry matter intake, milk yield, days in milk, and body weight, on Eeff, Neff, and the Neff:Eeff ratio was analyzed using mixed models. The interstudy correlation between Eeff and Neff was 0.62, whereas the intrastudy correlation was 0.30. The higher interstudy correlation was partly due to milk yield and dry matter intake being present in both Eeff and Neff. We, therefore, also explored the Neff:Eeff ratio. Energy efficiency was negatively associated with ADF and PCO, whereas Neff was negatively associated with ADF and digestible energy. The Neff:Eeff ratio was affected by ADF and PCO only. In conclusion, the results indicate a possibility to maximize feed efficiency in terms of both energy and nitrogen at the same time. In other words, an improvement in Eeff would also mean an improvement in Neff. The current study also shows that these types of transverse data are not sufficient to study the effect of animal factors, such as days in milk, on feed efficiency. Longitudinal measurements per animal would probably be more appropriate. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Scaling up the energy service company business: market status and company feedback in the Russian Federation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roshchanka, Volha; Evans, Meredydd

Many energy efficiency professionals have proposed using Energy Performance Contracts (EPCs) as a mechanism to improve public sector energy efficiency in countries with restrictive government budgets. However, in practice, most middle-income countries have used this mechanism only in a limited way. Russia offers an interesting case study because of its huge energy savings opportunities, increasing energy prices, robust political backing for public sector energy efficiency, and evolving legislation that supports EPCs. In 2009, the Russian Federation launched a program to reduce the energy intensity of the country’s large public sector, which accounts for 9 percent of Russia’s total energy consumption.more » To achieve energy efficiency goals, Russia experimented with its public procurement rules, adjusting them to encourage EPCs. We conducted structured interviews with Energy Service Companies (ESCOs) in Russia and supplemented them with online research. Our review shows that, to date, nearly 50 ESCOs signed about 150 contracts in public facilities. Most ESCO contracts in Russia are for 5 years, and they generally are small (under $100,000). ESCOs in Russia face a challenging environment, which leads to smaller projects. ESCOs also are concerned about costly and risky tender procedures, uncertainty regarding repayment from public facilities, the inability to expand projects, and financing. We discuss these challenges and propose potential solutions at policy and company levels. The ESCOs feedback regarding Russia’s experimental model can inform the country’s program for public sector energy efficiency and offer lessons for other countries attempting to develop the EPC mechanism.« less

Analysis and Optimization of Building Energy Consumption

NASA Astrophysics Data System (ADS)

Chuah, Jun Wei

Energy is one of the most important resources required by modern human society. In 2010, energy expenditures represented 10% of global gross domestic product (GDP). By 2035, global energy consumption is expected to increase by more than 50% from current levels. The increased pace of global energy consumption leads to significant environmental and socioeconomic issues: (i) carbon emissions, from the burning of fossil fuels for energy, contribute to global warming, and (ii) increased energy expenditures lead to reduced standard of living. Efficient use of energy, through energy conservation measures, is an important step toward mitigating these effects. Residential and commercial buildings represent a prime target for energy conservation, comprising 21% of global energy consumption and 40% of the total energy consumption in the United States. This thesis describes techniques for the analysis and optimization of building energy consumption. The thesis focuses on building retrofits and building energy simulation as key areas in building energy optimization and analysis. The thesis first discusses and evaluates building-level renewable energy generation as a solution toward building energy optimization. The thesis next describes a novel heating system, called localized heating. Under localized heating, building occupants are heated individually by directed radiant heaters, resulting in a considerably reduced heated space and significant heating energy savings. To support localized heating, a minimally-intrusive indoor occupant positioning system is described. The thesis then discusses occupant-level sensing (OLS) as the next frontier in building energy optimization. OLS captures the exact environmental conditions faced by each building occupant, using sensors that are carried by all building occupants. The information provided by OLS enables fine-grained optimization for unprecedented levels of energy efficiency and occupant comfort. The thesis also describes a retrofit-oriented building energy simulator, ROBESim, that natively supports building retrofits. ROBESim extends existing building energy simulators by providing a platform for the analysis of novel retrofits, in addition to simulating existing retrofits. Using ROBESim, retrofits can be automatically applied to buildings, obviating the need for users to manually update building characteristics for comparisons between different building retrofits. ROBESim also includes several ease-of-use enhancements to support users of all experience levels.

Analysis of Minimum Efficiency Performance Standards for Residential General Service Lighting in Chile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Letschert, Virginie E.; McNeil, Michael A.; Leiva Ibanez, Francisco Humberto

2011-06-01

Minimum Efficiency Performance Standards (MEPS) have been chosen as part of Chile's national energy efficiency action plan. As a first MEPS, the Ministry of Energy has decided to focus on a regulation for lighting that would ban the sale of inefficient bulbs, effectively phasing out the use of incandescent lamps. Following major economies such as the US (EISA, 2007) , the EU (Ecodesign, 2009) and Australia (AS/NZS, 2008) who planned a phase out based on minimum efficacy requirements, the Ministry of Energy has undertaken the impact analysis of a MEPS on the residential lighting sector. Fundacion Chile (FC) and Lawrencemore » Berkeley National Laboratory (LBNL) collaborated with the Ministry of Energy and the National Energy Efficiency Program (Programa Pais de Eficiencia Energetica, or PPEE) in order to produce a techno-economic analysis of this future policy measure. LBNL has developed for CLASP (CLASP, 2007) a spreadsheet tool called the Policy Analysis Modeling System (PAMS) that allows for evaluation of costs and benefits at the consumer level but also a wide range of impacts at the national level, such as energy savings, net present value of savings, greenhouse gas (CO2) emission reductions and avoided capacity generation due to a specific policy. Because historically Chile has followed European schemes in energy efficiency programs (test procedures, labelling program definitions), we take the Ecodesign commission regulation No 244/2009 as a starting point when defining our phase out program, which means a tiered phase out based on minimum efficacy per lumen category. The following data were collected in order to perform the techno-economic analysis: (1) Retail prices, efficiency and wattage category in the current market, (2) Usage data (hours of lamp use per day), and (3) Stock data, penetration of efficient lamps in the market. Using these data, PAMS calculates the costs and benefits of efficiency standards from two distinct but related perspectives: (1) The Life-Cycle Cost (LCC) calculation examines costs and benefits from the perspective of the individual household; and (2) The National Perspective projects the total national costs and benefits including both financial benefits, and energy savings and environmental benefits. The national perspective calculations are called the National Energy Savings (NES) and the Net Present Value (NPV) calculations. PAMS also calculate total emission mitigation and avoided generation capacity. This paper describes the data and methodology used in PAMS and presents the results of the proposed phase out of incandescent bulbs in Chile.« less

Minimizing energy dissipation of matrix multiplication kernel on Virtex-II

NASA Astrophysics Data System (ADS)

Choi, Seonil; Prasanna, Viktor K.; Jang, Ju-wook

2002-07-01

In this paper, we develop energy-efficient designs for matrix multiplication on FPGAs. To analyze the energy dissipation, we develop a high-level model using domain-specific modeling techniques. In this model, we identify architecture parameters that significantly affect the total energy (system-wide energy) dissipation. Then, we explore design trade-offs by varying these parameters to minimize the system-wide energy. For matrix multiplication, we consider a uniprocessor architecture and a linear array architecture to develop energy-efficient designs. For the uniprocessor architecture, the cache size is a parameter that affects the I/O complexity and the system-wide energy. For the linear array architecture, the amount of storage per processing element is a parameter affecting the system-wide energy. By using maximum amount of storage per processing element and minimum number of multipliers, we obtain a design that minimizes the system-wide energy. We develop several energy-efficient designs for matrix multiplication. For example, for 6×6 matrix multiplication, energy savings of upto 52% for the uniprocessor architecture and 36% for the linear arrary architecture is achieved over an optimized library for Virtex-II FPGA from Xilinx.

Recovery of the local gravity field by spherical regularization wavelets approximation and its numerical implementation

NASA Astrophysics Data System (ADS)

Shuler, Harrey Jeong

Information technology (IT) is becoming increasingly pervasive throughout society as more data is digitally processed, stored, and transferred. The infrastructure that supports IT activity is growing accordingly, and data center energy demands have increased by nearly a factor of four over the past decade. This dissertation investigates how building design and operation influence energy use and indoor air quality in data centers and provides strategies to improve both design goals simultaneously. As an initial step toward understanding data center air quality, measurements of particle concentrations were made at multiple operating northern California data centers. Ratios of measured particle concentrations in conventional data centers to the corresponding outside concentrations were significantly lower than those reported in the literature for office or residential buildings. Estimates using a material-balance model match well with empirical results, indicating that the dominant particle sources and losses---ventilation and filtration---have been characterized. Measurements taken at a data center using economizers show nearly an order of magnitude increase in particle concentration during economizer activity. However, even with the increase, the measured particle concentrations are still below concentration limits recommended in most industry standards. The research proceeds by exploring the feasibility of using economizers in data centers while simultaneously controlling particle concentrations with high-quality air filtration. Physical and chemical properties of indoor and outdoor particles were analyzed at a data center using economizers and varying levels of air filtration efficiency. Results show that when improved filtration is used in combination with an economizer, the indoor/outdoor concentration ratios for most measured particle types were similar to the measurements when using conventional filtration without economizers. An energy analysis of the data center reveals that, even during the summer months, chiller savings from economizer use greatly outweigh the increase in fan power associated with improved filtration. These findings indicate that economizer use combined with improved filtration could significantly reduce data center energy demand while providing a level of protection from particles of outdoor origin similar to that observed with conventional design. The emphasis of the dissertation then shifts to evaluate the energy benefits of economizer use in data centers under different design strategies. Economizer use with high ventilation rates is compared against an alternative, water-side economizer design that does not affect indoor particle concentrations. Building energy models are employed to estimate energy savings of both economizer designs for data centers in several climate zones in California. Results show that water-side economizers consistently provide less energy savings than air-side economizers, though the difference in savings varies by location. Model results also show that conventional limits on humidity levels in data centers can restrict the energy benefits of economizers. The modeling efforts are then extended to estimate national data center energy use. Different size data centers are modeled to represent the national variation in efficiency and operation of associated mechanical equipment. Results indicate increased energy efficiency opportunities with larger data centers and highlight the importance of temperature setpoints in maximizing economizer efficiency. A bottom-up modeling approach is used to estimate current (2008) United States data center energy use at nearly 62--70 billion kWh annually. The model indicates that more about 65--70% of this energy demand can be avoided through energy efficient IT and cooling infrastructure design, equivalent to an annual energy efficiency resource of approximately 40--50 billion kWh available at a national level. Within the context of greenhouse gas emissions, benefits can be significantly increased by incorporating site location into energy-efficient design strategies. (Abstract shortened by UMI.).

Techno-Economic Analysis of Indian Draft Standard Levels for RoomAir Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNeil, Michael A.; Iyer, Maithili

The Indian Bureau of Energy Efficiency (BEE) finalized its first set of efficiency standards and labels for room air conditioners in July of 2006. These regulations followed soon after the publication of levels for frost-free refrigerators in the same year. As in the case of refrigerators, the air conditioner program introduces Minimum Efficiency Performance Standards (MEPS) and comparative labels simultaneously, with levels for one to five stars. Also like the refrigerator program, BEE defined several successive program phases of increasing stringency. In support of BEE's refrigerator program, Lawrence Berkeley National Laboratory (LBNL) produced an analysis of national impacts of standardsmore » in collaboration with the Collaborative Labeling and Standards Program (CLASP). That analysis drew on LBNL's experience with standards programs in the United States, as well as many other countries. Subsequently, as part of the process for setting optimal levels for air conditioner regulations, CLASP commissioned LBNL to provide support to BEE in the form of a techno-economic evaluation of air conditioner efficiency technologies. This report describes the methodology and results of this techno-economic evaluation. The analysis consists of three components: (1) Cost effectiveness to consumers of efficiency technologies relative to current baseline. (2) Impacts on the current market from efficiency regulations. (3) National energy and financial impacts. The analysis relied on detailed and up-to-date technical data made available by BEE and industry representatives. Technical parameters were used in conjunction with knowledge about air conditioner use patterns in the residential and commercial sectors, and prevailing marginal electricity prices, in order to give an estimate of per-unit financial impacts. In addition, the overall impact of the program was evaluated by combining unit savings with market forecasts in order to yield national impacts. LBNL presented preliminary results of these analyses in May 2006, at a meeting of BEEs Technical Committee for Air Conditioners. This meeting was attended by a wide array of stakeholder, including industry representatives, engineers and consumer advocates. Comments made by stakeholders at this meeting are incorporated into the final analysis presented in this report. The current analysis begins with the Rating Plan drafted by BEE in 2006, along with an evaluation of the market baseline according to test data submitted by manufacturers. MEPS, label rating levels, and baseline efficiencies are presented in Section 2. First, we compare Indian MEPS with current standards in other countries, and assess their relative stringency. Baseline efficiencies are then used to estimate the fraction of models likely to remain on the market at each phase of the program, and the impact on market-weighted efficiency levels. Section 3 deals with cost-effectiveness of higher efficiency design options. The cost-benefit analysis is grounded in technical parameters provided by industry representatives in India. This data allows for an assessment of financial costs and benefits to consumers as a result of the standards and labeling program. A Life-Cycle Cost (LCC) calculation is used to evaluate the impacts of the program at the unit level, thus providing some insight into the appropriateness of the levels chosen, and additional opportunities for further ratcheting. In addition to LCC, we also calculate payback periods, cost of conserved energy (CCE), and return on investment (ROI). Finally, Section 4 covers national impacts. This is an extension of unit level estimates in the two previous sections. Extrapolation to the national level depends on a forecast of air conditioner purchases (shipments), which we describe here. Following the cost-benefit analysis, we construct several efficiency scenarios including the BEE plan, but also considering further potential for efficiency improvement. These are combined with shipments through a stock accounting model in order to forecast air conditioner energy consumption in each scenario, and associated electricity savings and carbon emission mitigation. Finally, financial costs and savings are scaled to the national level to evaluate net fiscal benefits.« less

Energy efficient strategy for throughput improvement in wireless sensor networks.

PubMed

Jabbar, Sohail; Minhas, Abid Ali; Imran, Muhammad; Khalid, Shehzad; Saleem, Kashif

2015-01-23

Network lifetime and throughput are one of the prime concerns while designing routing protocols for wireless sensor networks (WSNs). However, most of the existing schemes are either geared towards prolonging network lifetime or improving throughput. This paper presents an energy efficient routing scheme for throughput improvement in WSN. The proposed scheme exploits multilayer cluster design for energy efficient forwarding node selection, cluster heads rotation and both inter- and intra-cluster routing. To improve throughput, we rotate the role of cluster head among various nodes based on two threshold levels which reduces the number of dropped packets. We conducted simulations in the NS2 simulator to validate the performance of the proposed scheme. Simulation results demonstrate the performance efficiency of the proposed scheme in terms of various metrics compared to similar approaches published in the literature.

Energy Efficient Strategy for Throughput Improvement in Wireless Sensor Networks

PubMed Central

Jabbar, Sohail; Minhas, Abid Ali; Imran, Muhammad; Khalid, Shehzad; Saleem, Kashif

2015-01-01

Network lifetime and throughput are one of the prime concerns while designing routing protocols for wireless sensor networks (WSNs). However, most of the existing schemes are either geared towards prolonging network lifetime or improving throughput. This paper presents an energy efficient routing scheme for throughput improvement in WSN. The proposed scheme exploits multilayer cluster design for energy efficient forwarding node selection, cluster heads rotation and both inter- and intra-cluster routing. To improve throughput, we rotate the role of cluster head among various nodes based on two threshold levels which reduces the number of dropped packets. We conducted simulations in the NS2 simulator to validate the performance of the proposed scheme. Simulation results demonstrate the performance efficiency of the proposed scheme in terms of various metrics compared to similar approaches published in the literature. PMID:25625902

The Program Administrator Cost of Saved Energy for Utility Customer-Funded Energy Efficiency Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Billingsley, Megan A.; Hoffman, Ian M.; Stuart, Elizabeth

End-use energy efficiency is increasingly being relied upon as a resource for meeting electricity and natural gas utility system needs within the United States. There is a direct connection between the maturation of energy efficiency as a resource and the need for consistent, high-quality data and reporting of efficiency program costs and impacts. To support this effort, LBNL initiated the Cost of Saved Energy Project (CSE Project) and created a Demand-Side Management (DSM) Program Impacts Database to provide a resource for policy makers, regulators, and the efficiency industry as a whole. This study is the first technical report of themore » LBNL CSE Project and provides an overview of the project scope, approach, and initial findings, including: • Providing a proof of concept that the program-level cost and savings data can be collected, organized, and analyzed in a systematic fashion; • Presenting initial program, sector, and portfolio level results for the program administrator CSE for a recent time period (2009-2011); and • Encouraging state and regional entities to establish common reporting definitions and formats that would make the collection and comparison of CSE data more reliable. The LBNL DSM Program Impacts Database includes the program results reported to state regulators by more than 100 program administrators in 31 states, primarily for the years 2009–2011. In total, we have compiled cost and energy savings data on more than 1,700 programs over one or more program-years for a total of more than 4,000 program-years’ worth of data, providing a rich dataset for analyses. We use the information to report costs-per-unit of electricity and natural gas savings for utility customer-funded, end-use energy efficiency programs. The program administrator CSE values are presented at national, state, and regional levels by market sector (e.g., commercial, industrial, residential) and by program type (e.g., residential whole home programs, commercial new construction, commercial/industrial custom rebate programs). In this report, the focus is on gross energy savings and the costs borne by the program administrator—including administration, payments to implementation contractors, marketing, incentives to program participants (end users) and both midstream and upstream trade allies, and evaluation costs. We collected data on net savings and costs incurred by program participants. However, there were insufficient data on participant cost contributions, and uncertainty and variability in the ways in which net savings were reported and defined across states (and program administrators).« less

Investigating power capping toward energy-efficient scientific applications: Investigating Power Capping toward Energy-Efficient Scientific Applications

DOE PAGES

Haidar, Azzam; Jagode, Heike; Vaccaro, Phil; ...

2018-03-22

The emergence of power efficiency as a primary constraint in processor and system design poses new challenges concerning power and energy awareness for numerical libraries and scientific applications. Power consumption also plays a major role in the design of data centers, which may house petascale or exascale-level computing systems. At these extreme scales, understanding and improving the energy efficiency of numerical libraries and their related applications becomes a crucial part of the successful implementation and operation of the computing system. In this paper, we study and investigate the practice of controlling a compute system's power usage, and we explore howmore » different power caps affect the performance of numerical algorithms with different computational intensities. Further, we determine the impact, in terms of performance and energy usage, that these caps have on a system running scientific applications. This analysis will enable us to characterize the types of algorithms that benefit most from these power management schemes. Our experiments are performed using a set of representative kernels and several popular scientific benchmarks. Lastly, we quantify a number of power and performance measurements and draw observations and conclusions that can be viewed as a roadmap to achieving energy efficiency in the design and execution of scientific algorithms.« less

Investigating power capping toward energy-efficient scientific applications: Investigating Power Capping toward Energy-Efficient Scientific Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haidar, Azzam; Jagode, Heike; Vaccaro, Phil

The emergence of power efficiency as a primary constraint in processor and system design poses new challenges concerning power and energy awareness for numerical libraries and scientific applications. Power consumption also plays a major role in the design of data centers, which may house petascale or exascale-level computing systems. At these extreme scales, understanding and improving the energy efficiency of numerical libraries and their related applications becomes a crucial part of the successful implementation and operation of the computing system. In this paper, we study and investigate the practice of controlling a compute system's power usage, and we explore howmore » different power caps affect the performance of numerical algorithms with different computational intensities. Further, we determine the impact, in terms of performance and energy usage, that these caps have on a system running scientific applications. This analysis will enable us to characterize the types of algorithms that benefit most from these power management schemes. Our experiments are performed using a set of representative kernels and several popular scientific benchmarks. Lastly, we quantify a number of power and performance measurements and draw observations and conclusions that can be viewed as a roadmap to achieving energy efficiency in the design and execution of scientific algorithms.« less

Prospective Evaluation of the Energy and CO 2 Emissions Impact of China’s 2010 – 2013 Efficiency Standards for Products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khanna, Nina; Zhou, Nan; Fridley, David

Since China introduced its first mandatory minimum energy performance standards (MEPS) for eight major household products in 1989, its MEPS program has expanded significantly to cover nearly 60 residential, industrial and commercial products. In June of 2012, the pace of standards development for new and revised standards was further accelerated with the launch of the national “100 Energy Efficiency Standards.” Initiatives. An unprecedented 21 MEPS were adopted by China from 2012 to 2013, compared to only 7 MEPS adopted from 2010 to 2011. The Chinese MEPS program now covers 15 products in the residential sector, 15 types of commercial andmore » office equipment, 14 types of industrial equipment and 13 lighting products, making it one of the most comprehensive MEPS program in the world. This study provides an updated prospective evaluation of the potential energy and CO 2 impact of 23 of the 28 MEPS adopted by China from 2010 to 2013. This study updates a previous analysis (Zhou et al. 2011) by quantifying the additional potential energy and CO 2 reductions from the newest standards that have been adopted since 2010. The most recent actual and projected sales, usage, and efficiency data were collected for 14 product categories covered under 23 MEPS adopted between 2010 and 2013. Three scenarios are then used to quantify the energy and CO 2 reduction potential of the one-time implementation of these 23 MEPS, including a baseline counterfactual scenario, the actual MEPS scenario and a best available technologies efficiency scenario. The setting of the baseline efficiency is crucial to determining the savings potential of the new and revised MEPS and international best available technology efficiency levels, as it reflects the market average in the absence of MEPS. For this study, the average baseline is based on either the reported 2010 market-average efficiency if sales-weighted efficiency data is available for new product MEPS and selected products with revised MEPS, or the minimum efficiency requirement of the previous MEPS for products with revised MEPS from 2010 to 2013 that do not have sales-weighted efficiency data. Using sales-weighted efficiency data for the baseline help capture market transformation that has already occurred prior to the implementation of the MEPS, and can better differentiate the savings that are attributable to MEPS. The efficiency levels of best available technologies are taken from recent reviews of international commercially available best available technologies.« less

A Recursive Method for Calculating Certain Partition Functions.

ERIC Educational Resources Information Center

Woodrum, Luther; And Others

1978-01-01

Describes a simple recursive method for calculating the partition function and average energy of a system consisting of N electrons and L energy levels. Also, presents an efficient APL computer program to utilize the recursion relation. (Author/GA)

Increasing levels of rapeseed expeller meal in diets for pigs: effects on protein and energy metabolism.

PubMed

Pérez de Nanclares, M; Marcussen, C; Tauson, A-H; Hansen, J Ø; Kjos, N P; Mydland, L T; Bach Knudsen, K E; Øverland, M

2018-05-28

The heavy reliance on imported soybean meal (SBM) as a protein source makes it necessary for the European pig industry to search for alternatives and to develop pigs that perform efficiently when fed such ingredients. Digestion and metabolism are major physiological processes contributing to variation in feed efficiency. Therefore, an experiment was conducted to assess the effects of replacing SBM with increasing levels of rapeseed meal (RSM) in diets for young pigs on apparent total tract digestibility (ATTD) of energy and nutrients, nitrogen (N) balance, energy metabolism and carbohydrate, protein and fat oxidation. Four diets were fed to 32 pigs (22.7±4.1 kg initial BW) for three weeks. The diets consisted of a control cereal grain-SBM basal diet and three test diets where SBM and wheat were partially replaced with 10%, 20%, and 30% of expeller RSM. Increasing level of RSM in the diets linearly reduced ATTD of organic matter, CP, total carbohydrates, dietary fiber and energy. Utilization of digested nitrogen (DN) for N retention and total N excretion were not affected by RSM inclusion, however, RSM inclusion induced a shift in N excretion from urine to feces. Despite a linear increase in liver to metabolic BW ratio, heat production and utilization of metabolizable energy (ME) for retention were not affected by increasing RSM inclusion. In conclusion, replacing SBM with up to 30% of expeller RSM in nutritionally balanced diets for young pigs reduced the ATTD of most nutrients and energy, but did not affect N and energy retention in the body or efficiency of utilization of DN or ME for retention.

Effect of diet energy level and genomic residual feed intake on pre-bred dairy heifer feed intake and growth

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the growth, feed intake, and feed efficiency of pre-bred dairy heifers with different predicted genomic residual feed intakes as lactating cows (RFI), and offered diets with different energy levels. Pre-bred heifers (128, ages 4-9 months) were blocked by ...

Models of charge pair generation in organic solar cells.

PubMed

Few, Sheridan; Frost, Jarvist M; Nelson, Jenny

2015-01-28

Efficient charge pair generation is observed in many organic photovoltaic (OPV) heterojunctions, despite nominal electron-hole binding energies which greatly exceed the average thermal energy. Empirically, the efficiency of this process appears to be related to the choice of donor and acceptor materials, the resulting sequence of excited state energy levels and the structure of the interface. In order to establish a suitable physical model for the process, a range of different theoretical studies have addressed the nature and energies of the interfacial states, the energetic profile close to the heterojunction and the dynamics of excited state transitions. In this paper, we review recent developments underpinning the theory of charge pair generation and phenomena, focussing on electronic structure calculations, electrostatic models and approaches to excited state dynamics. We discuss the remaining challenges in achieving a predictive approach to charge generation efficiency.

The role of incline, performance level, and gender on the gross mechanical efficiency of roller ski skating

PubMed Central

Sandbakk, Øyvind; Hegge, Ann Magdalen; Ettema, Gertjan

2013-01-01

The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level, and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points [the Federation of International Skiing (FIS) approved scoring system for ski racing] where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r = −0.89 to 0.98 and P < 0.05 in all cases). Gross efficiency was higher at the steeper incline, both for men (17.1 ± 0.4 vs. 15.8 ± 0.5%, P < 0.05) and women (16.9 ± 0.5 vs. 15.7 ± 0.4%, P < 0.05), but without any gender differences being apparent. Significant correlations between gross efficiency and performance level were found for both inclines and genders (r = −0.65 to 0.81 and P < 0.05 in all cases). The current study demonstrated that cross-country skiers of both genders used less metabolic energy to perform the same amount of work at steeper inclines, and that the better ranked elite male and female skiers skied more efficiently. PMID:24155722

The role of incline, performance level, and gender on the gross mechanical efficiency of roller ski skating.

PubMed

Sandbakk, Oyvind; Hegge, Ann Magdalen; Ettema, Gertjan

2013-01-01

The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level, and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points [the Federation of International Skiing (FIS) approved scoring system for ski racing] where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r = -0.89 to 0.98 and P < 0.05 in all cases). Gross efficiency was higher at the steeper incline, both for men (17.1 ± 0.4 vs. 15.8 ± 0.5%, P < 0.05) and women (16.9 ± 0.5 vs. 15.7 ± 0.4%, P < 0.05), but without any gender differences being apparent. Significant correlations between gross efficiency and performance level were found for both inclines and genders (r = -0.65 to 0.81 and P < 0.05 in all cases). The current study demonstrated that cross-country skiers of both genders used less metabolic energy to perform the same amount of work at steeper inclines, and that the better ranked elite male and female skiers skied more efficiently.

National Energy Efficiency Evaluation, Measurement and Verification (EM&V) Standard: Scoping Study of Issues and Implementation Requirements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiller Consulting, Inc.; Schiller, Steven R.; Goldman, Charles A.

2011-02-04

This report is a scoping study that identifies issues associated with developing a national evaluation, measurement and verification (EM&V) standard for end-use, non-transportation, energy efficiency activities. The objectives of this study are to identify the scope of such a standard and define EM&V requirements and issues that will need to be addressed in a standard. To explore these issues, we provide and discuss: (1) a set of definitions applicable to an EM&V standard; (2) a literature review of existing guidelines, standards, and 'initiatives' relating to EM&V standards as well as a review of 'bottom-up' versus 'top-down' evaluation approaches; (3) amore » summary of EM&V related provisions of two recent federal legislative proposals (Congressman Waxman's and Markey's American Clean Energy and Security Act of 2009 and Senator Bingaman's American Clean Energy Leadership Act of 2009) that include national efficiency resource requirements; (4) an annotated list of issues that that are likely to be central to, and need to be considered when, developing a national EM&V standard; and (5) a discussion of the implications of such issues. There are three primary reasons for developing a national efficiency EM&V standard. First, some policy makers, regulators and practitioners believe that a national standard would streamline EM&V implementation, reduce costs and complexity, and improve comparability of results across jurisdictions; although there are benefits associated with each jurisdiction setting its own EM&V requirements based on their specific portfolio and evaluation budgets and objectives. Secondly, if energy efficiency is determined by the US Environmental Protection Agency to be a Best Available Control Technology (BACT) for avoiding criteria pollutant and/or greenhouse gas emissions, then a standard can be required for documenting the emission reductions resulting from efficiency actions. The third reason for a national EM&V standard is that such a standard is likely to be required as a result of future federal energy legislation that includes end-use energy efficiency, either as a stand-alone energy-efficiency resource standard (EERS) or as part of a clean energy or renewable energy standard. This study is focused primarily on this third reason and thus explores issues associated with a national EM&V standard if energy efficiency is a qualifying resource in federal clean energy legislation. Developing a national EM&V standard is likely to be a lengthy process; this study focuses on the critical first step of identifying the issues that must be addressed in a future standard. Perhaps the most fundamental of these issues is 'how good is good enough?' This has always been the fundamental issue of EM&V for energy efficiency and is a result of the counter-factual nature of efficiency. Counter-factual in that savings are not measured, but estimated to varying degrees of accuracy by comparing energy consumption after a project (program) is implemented with what is assumed to have been the consumption of energy in the absence of the project (program). Therefore, the how good is good enough question is a short version of asking how certain does one have to be of the energy savings estimate that results from EM&V activities and is that level of certainty properly balanced against the amount of effort (resources, time, money) that is utilized to obtain that level of certainty. The implication is that not only should energy efficiency investments be cost-effective, but EM&V investments should consider risk management principles and thus also balance the costs and value of information derived from EM&V (EM&V should also be cost-effective).« less

Environmental policy and technological change: The effects of economic incentives and direct regulation on energy-saving innovation

NASA Astrophysics Data System (ADS)

Newell, Richard G., Jr.

Over the long run, the impacts of environmental policies will be greatly affected by the influence these policies have on the rate and direction of technological change. In particular, the roles played by energy prices and product regulation in energy-saving technology innovation are exceptionally important considerations in modeling climate change and evaluating alternative policy options. We analyze the effects of energy prices and energy-efficiency regulations on the menu of air conditioner and water heater models available on the market over a period of more than three decades, measuring their innovation in terms of improvements in the products' underlying characteristics. Through estimation of a series of "characteristics transformation surfaces," we find that during less than four decades, substantial innovation in these products reduced the total capital and operating costs of air conditioning by one-half and water heating by more than one-fifth. Although the overall rate of innovation in these products appears to be independent of energy prices and regulations, the evidence suggests that the direction of innovation may be responsive to energy price changes. This would imply that energy price increases induced innovation in a direction that lowered the capital cost tradeoffs inherent in producing more energy-efficient products. The evidence supporting "regulation-induced" changes in these tradeoffs is much weaker. Our estimates indicate that about one- to two-fifths of the energy-efficiency improvements in these products from 1973 to 1993 were associated with historical changes in energy prices. We also find that this responsiveness to price changes increased substantially after product labeling requirements came into effect, and that minimum efficiency standards had a significant positive effect on average efficiency levels. Nonetheless, a sizeable portion of historical efficiency improvements in these technologies is associated with the products' overall rate of innovation. Looking forward, we estimate that energy taxes of 10 to 30 percent of retail prices could significantly increase the energy efficiency of the product menu. We predict that such taxes would lead to additional efficiency increases in air conditioners of 6 to 26 percent. We conclude that the price-induced component of energy-efficiency innovation should not be ignored when assessing alternative climate change policies.

Energy-Efficient Transmissions for Remote Wireless Sensor Networks: An Integrated HAP/Satellite Architecture for Emergency Scenarios

PubMed Central

Dong, Feihong; Li, Hongjun; Gong, Xiangwu; Liu, Quan; Wang, Jingchao

2015-01-01

A typical application scenario of remote wireless sensor networks (WSNs) is identified as an emergency scenario. One of the greatest design challenges for communications in emergency scenarios is energy-efficient transmission, due to scarce electrical energy in large-scale natural and man-made disasters. Integrated high altitude platform (HAP)/satellite networks are expected to optimally meet emergency communication requirements. In this paper, a novel integrated HAP/satellite (IHS) architecture is proposed, and three segments of the architecture are investigated in detail. The concept of link-state advertisement (LSA) is designed in a slow flat Rician fading channel. The LSA is received and processed by the terminal to estimate the link state information, which can significantly reduce the energy consumption at the terminal end. Furthermore, the transmission power requirements of the HAPs and terminals are derived using the gradient descent and differential equation methods. The energy consumption is modeled at both the source and system level. An innovative and adaptive algorithm is given for the energy-efficient path selection. The simulation results validate the effectiveness of the proposed adaptive algorithm. It is shown that the proposed adaptive algorithm can significantly improve energy efficiency when combined with the LSA and the energy consumption estimation. PMID:26404292

Energy-Efficient Transmissions for Remote Wireless Sensor Networks: An Integrated HAP/Satellite Architecture for Emergency Scenarios.

PubMed

Dong, Feihong; Li, Hongjun; Gong, Xiangwu; Liu, Quan; Wang, Jingchao

2015-09-03

A typical application scenario of remote wireless sensor networks (WSNs) is identified as an emergency scenario. One of the greatest design challenges for communications in emergency scenarios is energy-efficient transmission, due to scarce electrical energy in large-scale natural and man-made disasters. Integrated high altitude platform (HAP)/satellite networks are expected to optimally meet emergency communication requirements. In this paper, a novel integrated HAP/satellite (IHS) architecture is proposed, and three segments of the architecture are investigated in detail. The concept of link-state advertisement (LSA) is designed in a slow flat Rician fading channel. The LSA is received and processed by the terminal to estimate the link state information, which can significantly reduce the energy consumption at the terminal end. Furthermore, the transmission power requirements of the HAPs and terminals are derived using the gradient descent and differential equation methods. The energy consumption is modeled at both the source and system level. An innovative and adaptive algorithm is given for the energy-efficient path selection. The simulation results validate the effectiveness of the proposed adaptive algorithm. It is shown that the proposed adaptive algorithm can significantly improve energy efficiency when combined with the LSA and the energy consumption estimation.

Alternative Formats to Achieve More Efficient Energy Codes for Commercial Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conover, David R.; Rosenberg, Michael I.; Halverson, Mark A.

2013-01-26

This paper identifies and examines several formats or structures that could be used to create the next generation of more efficient energy codes and standards for commercial buildings. Pacific Northwest National Laboratory (PNNL) is funded by the U.S. Department of Energy’s Building Energy Codes Program (BECP) to provide technical support to the development of ANSI/ASHRAE/IES Standard 90.1. While the majority of PNNL’s ASHRAE Standard 90.1 support focuses on developing and evaluating new requirements, a portion of its work involves consideration of the format of energy standards. In its current working plan, the ASHRAE 90.1 committee has approved an energy goalmore » of 50% improvement in Standard 90.1-2013 relative to Standard 90.1-2004, and will likely be considering higher improvement targets for future versions of the standard. To cost-effectively achieve the 50% goal in manner that can gain stakeholder consensus, formats other than prescriptive must be considered. Alternative formats that include reducing the reliance on prescriptive requirements may make it easier to achieve these aggressive efficiency levels in new codes and standards. The focus on energy code and standard formats is meant to explore approaches to presenting the criteria that will foster compliance, enhance verification, and stimulate innovation while saving energy in buildings. New formats may also make it easier for building designers and owners to design and build the levels of efficiency called for in the new codes and standards. This paper examines a number of potential formats and structures, including prescriptive, performance-based (with sub-formats of performance equivalency and performance targets), capacity constraint-based, and outcome-based. The paper also discusses the pros and cons of each format from the viewpoint of code users and of code enforcers.« less

Single-Nanoflake Photo-Electrochemistry Reveals Champion and Spectator Flakes in Exfoliated MoSe 2 Films

DOE PAGES

Todt, Michael A.; Isenberg, Allan E.; Nanayakkara, Sanjini U.; ...

2018-03-06

Semiconducting transition-metal dichalcogenide (TMD) nanoflake thin films are promising large-area electrodes for photo-electrochemical solar energy conversion applications. However, their energy conversion efficiencies are typically much lower than those of bulk electrodes. It is unclear to what extent this efficiency gap stems from differences among nanoflakes (e.g., area, thickness, and surface structural features). It is also unclear whether individual exfoliated nanoflakes can achieve energy conversion efficiencies similar to those of bulk crystals. Here, we use a single-nanoflake photo-electrochemical approach to show that there are both highly active and completely inactive nanoflakes within a film. For the exfoliated MoSe 2 samples studiedmore » herein, 7% of nanoflakes are highly active champions, whose photocurrent efficiency exceeds that of the bulk crystal. However, 66% of nanoflakes are inactive spectators, which are mostly responsible for the overall lower photocurrent efficiency compared to the bulk crystal. The photocurrent collection efficiency increases with nanoflake area and decreases more at perimeter edges than at interior step edges. These observations, which are hidden in ensemble-level measurements, reveal the underlying performance issues of exfoliated TMD electrodes for photo-electrochemical energy conversion applications.« less

Interfacial Energy-Level Alignment for High-Performance All-Inorganic Perovskite CsPbBr3 Quantum Dot-Based Inverted Light-Emitting Diodes.

PubMed

Subramanian, Alagesan; Pan, Zhenghui; Zhang, Zhenbo; Ahmad, Imtiaz; Chen, Jing; Liu, Meinan; Cheng, Shuang; Xu, Yijun; Wu, Jun; Lei, Wei; Khan, Qasim; Zhang, Yuegang

2018-04-18

All-inorganic perovskite light-emitting diode (PeLED) has a high stability in ambient atmosphere, but it is a big challenge to achieve high performance of the device. Basically, device design, control of energy-level alignment, and reducing the energy barrier between adjacent layers in the architecture of PeLED are important factors to achieve high efficiency. In this study, we report a CsPbBr 3 -based PeLED with an inverted architecture using lithium-doped TiO 2 nanoparticles as the electron transport layer (ETL). The optimal lithium doping balances the charge carrier injection between the hole transport layer and ETL, leading to superior device performance. The device exhibits a current efficiency of 3 cd A -1 , a luminance efficiency of 2210 cd m -2 , and a low turn-on voltage of 2.3 V. The turn-on voltage is one of the lowest values among reported CsPbBr 3 -based PeLEDs. A 7-fold increase in device efficiencies has been obtained for lithium-doped TiO 2 compared to that for undoped TiO 2 -based devices.

Public Housing: A Tailored Approach to Energy Retrofits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dentz, Jordan; Conlin, Francis; Podorson, David

2014-06-01

More than 1 million HUD-supported public housing units provide rental housing for eligible low-income families across the country. A survey of over 100 public housing authorities (PHAs) across the country indicated that there is a high level of interest in developing low-cost solutions that improve energy efficiency and can be seamlessly included in the refurbishment process. Further, PHAs, have incentives (both internal and external) to reduce utility bills. ARIES worked with two PHAs to develop packages of energy efficiency retrofit measures the PHAs can cost effectively implement with their own staffs in the normal course of housing operations when unitsmore » are refurbished between occupancies. The energy efficiency turnover protocols emphasized air infiltration reduction, duct sealing and measures that improve equipment efficiency. ARIES documented implementation 10 ten housing units. Total source energy consumption savings was estimated at 6%-10% based on BEopt modeling with a simple payback of 1.7 to 2.2 years. At typical housing unit turnover rates, these measures could impact hundreds of thousands of units per year nationally.« less

Investigation of operating parameters on CO2 splitting by dielectric barrier discharge plasma

NASA Astrophysics Data System (ADS)

Pan, CHEN; Jun, SHEN; Tangchun, RAN; Tao, YANG; Yongxiang, YIN

2017-12-01

Experiments of CO2 splitting by dielectric barrier discharge (DBD) plasma were carried out, and the influence of CO2 flow rate, plasma power, discharge voltage, discharge frequency on CO2 conversion and process energy efficiency were investigated. It was shown that the absolute quantity of CO2 decomposed was only proportional to the amount of conductive electrons across the discharge gap, and the electron amount was proportional to the discharge power; the energy efficiency of CO2 conversion was almost a constant at a lower level, which was limited by CO2 inherent discharge character that determined a constant gap electric field strength. This was the main reason why CO2 conversion rate decreased as the CO2 flow rate increase and process energy efficiency was decreased a little as applied frequency increased. Therefore, one can improve the CO2 conversion by less feed flow rate or larger discharge power in DBD plasma, but the energy efficiency is difficult to improve.

Industry Efficiency and Total Factor Productivity Growth under Resources and Environmental Constraint in China

PubMed Central

Tao, Feng; Li, Ling; Xia, X. H.

2012-01-01

The growth of China's industry has been seriously depending on energy and environment. This paper attempts to apply the directional distance function and the Luenberger productivity index to measure the environmental efficiency, environmental total factor productivity, and its components at the level of subindustry in China over the period from 1999 to 2009 while considering energy consumption and emission of pollutants. This paper also empirically examines the determinants of efficiency and productivity change. The major findings are as follows. Firstly, the main sources of environmental inefficiency of China's industry are the inefficiency of gross industrial output value, the excessive energy consumption, and pollutant emissions. Secondly, the highest growth rate of environmental total factor productivity among the three industrial categories is manufacturing, followed by mining, and production and supply of electricity, gas, and water. Thirdly, foreign direct investment, capital-labor ratio, ownership structure, energy consumption structure, and environmental regulation have varying degrees of effects on the environmental efficiency and environmental total factor productivity. PMID:23365517

Industry efficiency and total factor productivity growth under resources and environmental constraint in China.

PubMed

Tao, Feng; Li, Ling; Xia, X H

2012-01-01

The growth of China's industry has been seriously depending on energy and environment. This paper attempts to apply the directional distance function and the Luenberger productivity index to measure the environmental efficiency, environmental total factor productivity, and its components at the level of subindustry in China over the period from 1999 to 2009 while considering energy consumption and emission of pollutants. This paper also empirically examines the determinants of efficiency and productivity change. The major findings are as follows. Firstly, the main sources of environmental inefficiency of China's industry are the inefficiency of gross industrial output value, the excessive energy consumption, and pollutant emissions. Secondly, the highest growth rate of environmental total factor productivity among the three industrial categories is manufacturing, followed by mining, and production and supply of electricity, gas, and water. Thirdly, foreign direct investment, capital-labor ratio, ownership structure, energy consumption structure, and environmental regulation have varying degrees of effects on the environmental efficiency and environmental total factor productivity.

A tale of two cities: Comparison of impacts on CO2 emissions, the indoor environment and health of home energy efficiency strategies in London and Milton Keynes

NASA Astrophysics Data System (ADS)

Shrubsole, C.; Das, P.; Milner, J.; Hamilton, I. G.; Spadaro, J. V.; Oikonomou, E.; Davies, M.; Wilkinson, P.

2015-11-01

Dwellings are a substantial source of global CO2 emissions. The energy used in homes for heating, cooking and running electrical appliances is responsible for a quarter of current total UK emissions and is a key target of government policies for greenhouse gas abatement. Policymakers need to understand the potential impact that such decarbonization policies have on the indoor environment and health for a full assessment of costs and benefits. We investigated these impacts in two contrasting settings of the UK: London, a predominantly older city and Milton Keynes, a growing new town. We employed SCRIBE, a building physics-based health impact model of the UK housing stock linked to the English Housing Survey, to examine changes, 2010-2050, in end-use energy demand, CO2 emissions, winter indoor temperatures, airborne pollutant concentrations and associated health impacts. For each location we modelled the existing (2010) housing stock and three future scenarios with different levels of energy efficiency interventions combined with either a business-as-usual, or accelerated decarbonization of the electricity grid approach. The potential for CO2 savings was appreciably greater in London than Milton Keynes except when substantial decarbonization of the electricity grid was assumed, largely because of the lower level of current energy efficiency in London and differences in the type and form of the housing stock. The average net impact on health per thousand population was greater in magnitude under all scenarios in London compared to Milton Keynes and more beneficial when it was assumed that purpose-provided ventilation (PPV) would be part of energy efficiency interventions, but more detrimental when interventions were assumed not to include PPV. These findings illustrate the importance of considering ventilation measures for health protection and the potential variation in the impact of home energy efficiency strategies, suggesting the need for tailored policy approaches in different locations, rather than adopting a universally rolled out strategy.

40 CFR 63.7533 - Can I use efficiency credits earned from implementation of energy conservation measures to comply...

Code of Federal Regulations, 2014 CFR

2014-07-01

... the implementation plan for efficiency credits to the Administrator for review and approval no later... level adjusted by applying the efficiency credits earned, lb per million Btu steam output (or lb per MWh) for the affected boiler. Em = Emissions measured during the performance test, lb per million Btu steam...

40 CFR 63.7533 - Can I use efficiency credits earned from implementation of energy conservation measures to comply...

Code of Federal Regulations, 2013 CFR

2013-07-01

... the implementation plan for efficiency credits to the Administrator for review and approval no later... level adjusted by applying the efficiency credits earned, lb per million Btu steam output (or lb per MWh) for the affected boiler. Em = Emissions measured during the performance test, lb per million Btu steam...

Existing Whole-House Solutions Case Study: Retrofitting a 1960s Split-Level Cold-Climate Home

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puttagunta, S.

2015-08-01

National programs such as Home Performance with ENERGY STAR® and numerous other utility air sealing programs have brought awareness to homeowners of the benefits of energy efficiency retrofits. Yet, these programs tend to focus on the low-hanging fruit: air-sealing the thermal envelope and ductwork where accessible, switch to efficient lighting, and low-flow fixtures. At the other end of the spectrum, deep-energy retrofit programs are also being encouraged by various utilities across the country. While deep energy retrofits typically seek 50% energy savings, they are often quite costly and most applicable to gut-rehab projects. A significant potential for lowering energy usagemore » in existing homes lies between the low hanging fruit and deep energy retrofit approaches - retrofits that save approximately 30% in energy over the existing conditions.« less

[Food value of spiruline algae for growth of the broiler-type chicken].

PubMed

Blum, J C; Calet, C

1975-01-01

Five trials were carried out during the growth (0-8 weeks) of the broiler type chicken. The weight increase was always depressed when spiruline algae replaced traditional protein sources (soybean meal, fish meal, ...) in a complete and well balanced diet (trials 1 and 2). The delay in growth was small and non significant for 5 p. 100 or less of spirulines in the diet. However, for the highest levels of spirulines the delay in growth was more pronounced, especially during the starting period (0-4 weeks): live weight gain was reduced from 16 and 26 per cent for the spirulines levels of 20 and 30 p. 100. Different methods (live weight gain, balance technique, body analysis) were used for the determination of the protein and energy efficiencies. Spirulines were fed at different levels, either added to a protein free diet (trial 3), or included with other protein sources in complete diets (trial 4). Both protein and energy efficiencies were reduced when the spiruline level increased. Thus, the protein efficiency of the spirulines was found to be similar to that of the other traditional protein sources (soybean, fish,...) for a level lower than 10 p. 100. In contrast, it was reduced (--20 p. 100) when more than 20 p. 100 of algae were included in the diet. The average metabolizable energy was 2,487 kcal per kilogram when 20 and 30 p. 100 of algae were added in the protein free diet. In the complete diets, this value was found to be smaller or greater according to the level of spirulines, 30 p. 100 reduced and 5 p. 100 increased the energy value. The poor digestibility of some glucidic fraction in the algae seems responsible for the low energy value and for the reduced growth performance. The addition of a glycolytic enzyme to the diet failed to improve the performance (trial 5).

A gas circulation and purification system for gas-cell-based low-energy RI-beam production.

PubMed

Sonoda, T; Tsubota, T; Wada, M; Katayama, I; Kojima, T M; Reponen, M

2016-06-01

A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part per billion is achieved with this method.

A gas circulation and purification system for gas-cell-based low-energy RI-beam production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sonoda, T.; Wada, M.; Katayama, I.

A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part permore » billion is achieved with this method.« less

The performance of the jet trigger for the ATLAS detector during 2011 data taking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aad, G.; Abbott, B.; Abdallah, J.

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by themore » trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction.« less

The performance of the jet trigger for the ATLAS detector during 2011 data taking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aad, G.; Abbott, B.; Abdallah, J.

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Eventsmore » are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction.« less

The performance of the jet trigger for the ATLAS detector during 2011 data taking

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2016-09-27

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by themore » trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction.« less

The performance of the jet trigger for the ATLAS detector during 2011 data taking.

PubMed

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Tojo, J; Tokár, S; Tokushuku, K; Tolley, E; Tomlinson, L; Tomoto, M; Tompkins, L; Toms, K; Tong, B; Torrence, E; Torres, H; Pastor, E Torró; Toth, J; Touchard, F; Tovey, D R; Trefzger, T; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Tripiana, M F; Trischuk, W; Trocmé, B; Trofymov, A; Troncon, C; Trottier-McDonald, M; Trovatelli, M; Truong, L; Trzebinski, M; Trzupek, A; Tseng, J C-L; Tsiareshka, P V; Tsipolitis, G; Tsirintanis, N; Tsiskaridze, S; Tsiskaridze, V; Tskhadadze, E G; Tsui, K M; Tsukerman, I I; Tsulaia, V; Tsuno, S; Tsybychev, D; Tudorache, A; Tudorache, V; Tuna, A N; Tupputi, S A; Turchikhin, S; Turecek, D; Turgeman, D; Turra, R; Turvey, A J; Tuts, P M; Tyndel, M; Ucchielli, G; Ueda, I; Ueno, R; Ughetto, M; Ukegawa, F; Unal, G; Undrus, A; Unel, G; Ungaro, F C; Unno, Y; Unverdorben, C; Urban, J; Urquijo, P; Urrejola, P; Usai, G; Usanova, A; Vacavant, L; Vacek, V; Vachon, B; Valderanis, C; Santurio, E Valdes; Valencic, N; Valentinetti, S; Valero, A; Valery, L; Valkar, S; Vallecorsa, S; Ferrer, J A Valls; Van Den Wollenberg, W; Van Der Deijl, P C; van der Geer, R; van der Graaf, H; van Eldik, N; van Gemmeren, P; Van Nieuwkoop, J; van Vulpen, I; van Woerden, M C; Vanadia, M; Vandelli, W; Vanguri, R; Vaniachine, A; Vankov, P; Vardanyan, G; Vari, R; Varnes, E W; Varol, T; Varouchas, D; Vartapetian, A; Varvell, K E; Vasquez, J G; Vazeille, F; Schroeder, T Vazquez; Veatch, J; Veloce, L M; Veloso, F; Veneziano, S; Ventura, A; Venturi, M; Venturi, N; Venturini, A; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vest, A; Vetterli, M C; Viazlo, O; Vichou, I; Vickey, T; Boeriu, O E Vickey; Viehhauser, G H A; Viel, S; Vigani, L; Vigne, R; Villa, M; Perez, M Villaplana; Vilucchi, E; Vincter, M G; Vinogradov, V B; Vittori, C; Vivarelli, I; Vlachos, S; Vlasak, M; Vogel, M; Vokac, P; Volpi, G; Volpi, M; von der Schmitt, H; von Toerne, E; Vorobel, V; Vorobev, K; Vos, M; Voss, R; Vossebeld, J H; Vranjes, N; Milosavljevic, M Vranjes; Vrba, V; Vreeswijk, M; Vuillermet, R; Vukotic, I; Vykydal, Z; Wagner, P; Wagner, W; Wahlberg, H; Wahrmund, S; Wakabayashi, J; Walder, J; Walker, R; Walkowiak, W; Wallangen, V; Wang, C; Wang, C; Wang, F; Wang, H; Wang, H; Wang, J; Wang, J; Wang, K; Wang, R; Wang, S M; Wang, T; Wang, T; Wang, X; Wanotayaroj, C; Warburton, A; Ward, C P; Wardrope, D R; Washbrook, A; Watkins, P M; Watson, A T; Watson, I J; Watson, M F; Watts, G; Watts, S; Waugh, B M; Webb, S; Weber, M S; Weber, S W; Webster, J S; Weidberg, A R; Weinert, B; Weingarten, J; Weiser, C; Weits, H; Wells, P S; Wenaus, T; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Wessels, M; Wetter, J; Whalen, K; Whallon, N L; Wharton, A M; White, A; White, M J; White, R; White, S; Whiteson, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik-Fuchs, L A M; Wildauer, A; Wilk, F; Wilkens, H G; Williams, H H; Williams, S; Willis, C; Willocq, S; Wilson, J A; Wingerter-Seez, I; Winklmeier, F; Winston, O J; Winter, B T; Wittgen, M; Wittkowski, J; Wollstadt, S J; Wolter, M W; Wolters, H; Wosiek, B K; Wotschack, J; Woudstra, M J; Wozniak, K W; Wu, M; Wu, M; Wu, S L; Wu, X; Wu, Y; Wyatt, T R; Wynne, B M; Xella, S; Xu, D; Xu, L; Yabsley, B; Yacoob, S; Yakabe, R; Yamaguchi, D; Yamaguchi, Y; Yamamoto, A; Yamamoto, S; Yamanaka, T; Yamauchi, K; Yamazaki, Y; Yan, Z; Yang, H; Yang, H; Yang, Y; Yang, Z; Yao, W-M; Yap, Y C; Yasu, Y; Yatsenko, E; Wong, K H Yau; Ye, J; Ye, S; Yeletskikh, I; Yen, A L; Yildirim, E; Yorita, K; Yoshida, R; Yoshihara, K; Young, C; Young, C J S; Youssef, S; Yu, D R; Yu, J; Yu, J M; Yu, J; Yuan, L; Yuen, S P Y; Yusuff, I; Zabinski, B; Zaidan, R; Zaitsev, A M; Zakharchuk, N; Zalieckas, J; Zaman, A; Zambito, S; Zanello, L; Zanzi, D; Zeitnitz, C; Zeman, M; Zemla, A; Zeng, J C; Zeng, Q; Zengel, K; Zenin, O; Ženiš, T; Zerwas, D; Zhang, D; Zhang, F; Zhang, G; Zhang, H; Zhang, J; Zhang, L; Zhang, R; Zhang, R; Zhang, X; Zhang, Z; Zhao, X; Zhao, Y; Zhao, Z; Zhemchugov, A; Zhong, J; Zhou, B; Zhou, C; Zhou, L; Zhou, L; Zhou, M; Zhou, N; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zhukov, K; Zibell, A; Zieminska, D; Zimine, N I; Zimmermann, C; Zimmermann, S; Zinonos, Z; Zinser, M; Ziolkowski, M; Živković, L; Zobernig, G; Zoccoli, A; Nedden, M Zur; Zurzolo, G; Zwalinski, L

2016-01-01

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton-proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon-nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction.

Spatial exciton allocation strategy with reduced energy loss for high-efficiency fluorescent/phosphorescent hybrid white organic light-emitting diodes

DOE PAGES

Zhao, Fangchao; Wei, Ying; Xu, Hui; ...

2017-05-17

Due to the poor operational lifetime of blue phosphorescent dopants and blue thermally activated delayed fluorescent (TADF) materials, hybrid white organic light-emitting diodes (WOLEDs) with conventional blue fluorescent emitters are still preferred for commercial applications in general lighting. However, the improvement in the overall efficiency of hybrid WOLEDs has been limited due to energy losses during the energy transfer process and exciton quenching after the spatial separation of the singlet and triplet excitons. Here we demonstrate the development of a Spatial Exciton Allocation Strategy (SEAS) to achieve close to 100% internal quantum efficiency (IQE) in blue-yellow complementary color hybrid WOLEDs.more » The employed blue fluorophore not only has a resonant triplet level with the yellow phosphor to reduce energy loss during energy transfer processes and triplet–triplet annihilation (TTA), but also has a resonant singlet level with the electron transport layer to extend singlet exciton distribution and enhance both singlet and triplet exciton utilization. Thus, the resulting hybrid WOLEDs exhibited 104 lm W -1 efficacy at 100 cd m -2 and 74 lm W -1 at 1000 cd m -2 with CIE coordinates of (0.42, 0.44) which is warm white and suitable for indoor lighting.« less

Spatial exciton allocation strategy with reduced energy loss for high-efficiency fluorescent/phosphorescent hybrid white organic light-emitting diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Fangchao; Wei, Ying; Xu, Hui

Due to the poor operational lifetime of blue phosphorescent dopants and blue thermally activated delayed fluorescent (TADF) materials, hybrid white organic light-emitting diodes (WOLEDs) with conventional blue fluorescent emitters are still preferred for commercial applications in general lighting. However, the improvement in the overall efficiency of hybrid WOLEDs has been limited due to energy losses during the energy transfer process and exciton quenching after the spatial separation of the singlet and triplet excitons. Here we demonstrate the development of a Spatial Exciton Allocation Strategy (SEAS) to achieve close to 100% internal quantum efficiency (IQE) in blue-yellow complementary color hybrid WOLEDs.more » The employed blue fluorophore not only has a resonant triplet level with the yellow phosphor to reduce energy loss during energy transfer processes and triplet–triplet annihilation (TTA), but also has a resonant singlet level with the electron transport layer to extend singlet exciton distribution and enhance both singlet and triplet exciton utilization. Thus, the resulting hybrid WOLEDs exhibited 104 lm W -1 efficacy at 100 cd m -2 and 74 lm W -1 at 1000 cd m -2 with CIE coordinates of (0.42, 0.44) which is warm white and suitable for indoor lighting.« less

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

PubMed

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

PubMed Central

Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency. PMID:28594862

REDOX electrochemical energy storage

NASA Technical Reports Server (NTRS)

Thaller, L. H.

1980-01-01

Reservoirs of chemical solutions can store electrical energy with high efficiency. Reactant solutions are stored outside conversion section where charging and discharging reactions take place. Conversion unit consists of stacks of cells connected together in parallel hydraulically, and in series electrically. Stacks resemble fuel cell batteries. System is 99% ampere-hour efficient, 75% watt hour efficient, and has long projected lifetime. Applications include storage buffering for remote solar or wind power systems, and industrial load leveling. Cost estimates are $325/kW of power requirement plus $51/kWh storage capacity. Mass production would reduce cost by about factor of two.

Solar Innovator | Alta Devices

ScienceCinema

Mattos, Laila; Le, Minh

2017-12-09

Selected to participate in the Energy Department's SunShot Initiative, Alta Devices produces solar cells that convert sunlight into electricity at world record-breaking levels of efficiency. Through its innovative solar technology Alta is helping bring down the cost of solar. Learn more about the Energy Department's efforts to advance solar technology at energy.gov/solar .

Photovoltaic conversion efficiency of InN/InxGa1-xN quantum dot intermediate band solar cells

NASA Astrophysics Data System (ADS)

Ben Afkir, N.; Feddi, E.; Dujardin, F.; Zazoui, M.; Meziane, J.

2018-04-01

The behavior of InN/InxGa1-xN spherical quantum dots solar cell is investigated, considering the internal electric field induced by the polarization of the junction. In order to determine the position of the intermediate band (IB), we present an efficient numerical technique based on difference finite method to solve the 3D time-independent Schrödinger's equation in spherical coordinates. The resultant n × n Hamiltonian matrix when considering n discrete points in spatial direction is diagonalized in order to calculate energy levels. Thus, the interband and intersubband transitions are determined, taking into consideration the effect of the internal electric field, size dots, interdot distances, and indium content on the energy levels, optical transition, photo-generated current density, open-circuit voltage and power conversion efficiency of the QD-IBSCs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martel, Laura; Smith, Paul; Rizea, Steven

The Ocean Thermal Energy Conversion (OTEC) Life Cycle Cost Assessment (OLCCA) is a study performed by members of the Lockheed Martin (LM) OTEC Team under funding from the Department of Energy (DOE), Award No. DE-EE0002663, dated 01/01/2010. OLCCA objectives are to estimate procurement, operations and maintenance, and overhaul costs for two types of OTEC plants: -Plants moored to the sea floor where the electricity produced by the OTEC plant is directly connected to the grid ashore via a marine power cable (Grid Connected OTEC plants) -Open-ocean grazing OTEC plant-ships producing an energy carrier that is transported to designated ports (Energymore » Carrier OTEC plants) Costs are developed using the concept of levelized cost of energy established by DOE for use in comparing electricity costs from various generating systems. One area of system costs that had not been developed in detail prior to this analysis was the operations and sustainment (O&S) cost for both types of OTEC plants. Procurement costs, generally referred to as capital expense and O&S costs (operations and maintenance (O&M) costs plus overhaul and replacement costs), are assessed over the 30 year operational life of the plants and an annual annuity calculated to achieve a levelized cost (constant across entire plant life). Dividing this levelized cost by the average annual energy production results in a levelized cost of electricity, or LCOE, for the OTEC plants. Technical and production efficiency enhancements that could result in a lower value of the OTEC LCOE were also explored. The thermal OTEC resource for Oahu, Hawaii and projected build out plan were developed. The estimate of the OTEC resource and LCOE values for the planned OTEC systems enable this information to be displayed as energy supplied versus levelized cost of the supplied energy; this curve is referred to as an Energy Supply Curve. The Oahu Energy Supply Curve represents initial OTEC deployment starting in 2018 and demonstrates the predicted economies of scale as technology and efficiency improvements are realized and larger more economical plants deployed. Utilizing global high resolution OTEC resource assessment from the Ocean Thermal Extractable Energy Visualization (OTEEV) project (an independent DOE project), Global Energy Supply Curves were generated for Grid Connected and Energy Carrier OTEC plants deployed in 2045 when the predicted technology and efficiencies improvements are fully realized. The Global Energy Supply Curves present the LCOE versus capacity in ascending order with the richest, lowest cost resource locations being harvested first. These curves demonstrate the vast ocean thermal resource and potential OTEC capacity that can be harvested with little change in LCOE.« less

Matching Charge Extraction Contact for Wide-Bandgap Perovskite Solar Cells.

PubMed

Lin, Yuze; Chen, Bo; Zhao, Fuwen; Zheng, Xiaopeng; Deng, Yehao; Shao, Yuchuan; Fang, Yanjun; Bai, Yang; Wang, Chunru; Huang, Jinsong

2017-07-01

Efficient wide-bandgap (WBG) perovskite solar cells are needed to boost the efficiency of silicon solar cells to beyond Schottky-Queisser limit, but they suffer from a larger open circuit voltage (V OC ) deficit than narrower bandgap ones. Here, it is shown that one major limitation of V OC in WBG perovskite solar cells comes from the nonmatched energy levels of charge transport layers. Indene-C60 bisadduct (ICBA) with higher-lying lowest-unoccupied-molecular-orbital is needed for WBG perovskite solar cells, while its energy-disorder needs to be minimized before a larger V OC can be observed. A simple method is applied to reduce the energy disorder by isolating isomer ICBA-tran3 from the as-synthesized ICBA-mixture. WBG perovskite solar cells with ICBA-tran3 show enhanced V OC by 60 mV, reduced V OC deficit of 0.5 V, and then a record stabilized power conversion efficiency of 18.5%. This work points out the importance of matching the charge transport layers in perovskite solar cells when the perovskites have a different composition and energy levels. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Explaining rISC and 100% efficient TADF (Conference Presentation)

NASA Astrophysics Data System (ADS)

Monkman, Andrew P.; Etherington, Marc; Graves, David; Data, Przemyslaw; Dos Santos, Paloma Lays; Nobuyasu, Roberto; Baiao Dias, Fernando M.

2016-09-01

Detailed photophysical measurements of intramolecular charge transfer (ICT) states have been made both in solution and solid state. Temperature dependent time resolved emission, delayed emission and photoinduced absorption are used to map the energy levels involved in molecule decay, and through detailed kinetic modelling of the thermally activated processes observed, true electron exchange energies and other energy barriers of the systems determined with the real states involved in the reversed intersystem crossing mechanism elucidated. For specific donor acceptor molecules, the CT singlet and local triplet states (of donor or acceptor) are found to be the lowest lying excited states of the molecule with very small energy barrier between them ? kT. In these cases the decay kinetics of the molecules become significantly different to normal molecules, and the effect of rapid recycling between CT singlet and local triplet states is observed which gives rise to the true triplet harvesting mechanism in TADF. Using a series of different TADF emitters we will show how the energy level ordering effects or does not effect TADF and how ultimate OLED performance is dictated by energy level ordering, from 5% to 22% external quantum efficiency. From this understanding, we are able to define three criterion for TADF in different molecules and these will be discussed.

Experimental demonstration of plasmon enhanced energy transfer rate in NaYF4:Yb3+,Er3+ upconversion nanoparticles

PubMed Central

Lu, Dawei; Mao, Chenchen; Cho, Suehyun K.; Ahn, Sungmo; Park, Wounjhang

2016-01-01

Energy transfer upconversion (ETU) is known to be the most efficient frequency upconversion mechanism. Surface plasmon can further enhance the upconversion process, opening doors to many applications. However, ETU is a complex process involving competing transitions between multiple energy levels and it has been difficult to precisely determine the enhancement mechanisms. In this paper, we report a systematic study on the dynamics of the ETU process in NaYF4:Yb3+,Er3+ nanoparticles deposited on plasmonic nanograting structure. From the transient near-infrared photoluminescence under various excitation power densities, we observed faster energy transfer rates under stronger excitation conditions until it reached saturation where the highest internal upconversion efficiency was achieved. The experimental data were analyzed using the complete set of rate equations. The internal upconversion efficiency was found to be 56% and 36%, respectively, with and without the plasmonic nanograting. We also analyzed the transient green emission and found that it is determined by the infrared transition rate. To our knowledge, this is the first report of experimentally measured internal upconversion efficiency in plasmon enhanced upconversion material. Our work decouples the internal upconversion efficiency from the overall upconverted luminescence efficiency, allowing more targeted engineering for efficiency improvement. PMID:26739230

Improving health and energy efficiency through community-based housing interventions.

PubMed

Howden-Chapman, Philippa; Crane, Julian; Chapman, Ralph; Fougere, Geoff

2011-12-01

Houses designed for one climate and cultural group may not be appropriate for other places and people. Our aim is to find cost-effective ways to improve the characteristics of older homes, ill-fitted for New Zealand's climate, in order to improve the occupants' health. We have carried out two community randomised trials, in partnership with local communities, which have focused on retrofitted insulation and more effective heating and have two other studies under way, one which focuses on electricity vouchers and the other on housing hazard remediation. The Housing, Insulation and Health Study showed that insulating 1,350 houses, built before insulation was required, improved the occupants' health and well being as well as household energy efficiency. In the Housing, Heating and Health Study we investigated the impact of installing more effective heating in insulated houses for 409 households, where there was a child with doctor-diagnosed asthma. Again, the study showed significant results in the intervention group; indoor temperatures increased and levels of NO(2) were halved. Children reported less poor health, lower levels of asthma symptoms and sleep disturbances by wheeze and dry cough. Children also had fewer days off school. Improving the energy efficiency of older housing leads to health improvements and energy efficiency improvements. Multidisciplinary studies of housing interventions can create compelling evidence to support policies for sustainable housing developments which improve health.

UV emissions from low energy artificial light sources.

PubMed

Fenton, Leona; Moseley, Harry

2014-01-01

Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Implementation study of wearable sensors for activity recognition systems.

PubMed

Rezaie, Hamed; Ghassemian, Mona

2015-08-01

This Letter investigates and reports on a number of activity recognition methods for a wearable sensor system. The authors apply three methods for data transmission, namely 'stream-based', 'feature-based' and 'threshold-based' scenarios to study the accuracy against energy efficiency of transmission and processing power that affects the mote's battery lifetime. They also report on the impact of variation of sampling frequency and data transmission rate on energy consumption of motes for each method. This study leads us to propose a cross-layer optimisation of an activity recognition system for provisioning acceptable levels of accuracy and energy efficiency.

Distributed Coordination of Energy Storage with Distributed Generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Tao; Wu, Di; Stoorvogel, Antonie A.

2016-07-18

With a growing emphasis on energy efficiency and system flexibility, a great effort has been made recently in developing distributed energy resources (DER), including distributed generators and energy storage systems. This paper first formulates an optimal coordination problem considering constraints at both system and device levels, including power balance constraint, generator output limits, storage energy and power capacity and charging/discharging efficiencies. An algorithm is then proposed to dynamically and automatically coordinate DERs in a distributed manner. With the proposed algorithm, the agent at each DER only maintains a local incremental cost and updates it through information exchange with a fewmore » neighbors, without relying on any central decision maker. Simulation results are used to illustrate and validate the proposed algorithm.« less

Technical Support Document: 50% Energy Savings Design Technology Packages for Highway Lodging Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Wei; Gowri, Krishnan; Lane, Michael D.

2009-09-28

This Technical Support Document (TSD) describes the process, methodology and assumptions for development of the 50% Energy Savings Design Technology Packages for Highway Lodging Buildings, a design guidance document intended to provide recommendations for achieving 50% energy savings in highway lodging properties over the energy-efficiency levels contained in ANSI/ASHRAE/IESNA Standard 90.1-2004, Energy Standard for Buildings Except Low-Rise Residential Buildings.

From Zero Energy Buildings to Zero Energy Districts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polly, Ben; Kutscher, Chuck; Macumber, Dan

Some U.S. cities are planning advanced districts that have goals for zero energy, water, waste, and/or greenhouse gas emissions. From an energy perspective, zero energy districts present unique opportunities to cost-effectively achieve high levels of energy efficiency and renewable energy penetration across a collection of buildings that may be infeasible at the individual building scale. These high levels of performance are accomplished through district energy systems that harness renewable and wasted energy at large scales and flexible building loads that coordinate with variable renewable energy supply. Unfortunately, stakeholders face a lack of documented processes, tools, and best practices to assistmore » them in achieving zero energy districts. The National Renewable Energy Laboratory (NREL) is partnering on two new district projects in Denver: the National Western Center and the Sun Valley Neighborhood. We are working closely with project stakeholders in their zero energy master planning efforts to develop the resources needed to resolve barriers and create replicable processes to support future zero energy district efforts across the United States. Initial results of these efforts include the identification and description of key zero energy district design principles (maximizing building efficiency, solar potential, renewable thermal energy, and load control), economic drivers, and master planning principles. The work has also resulted in NREL making initial enhancements to the U.S. Department of Energy's open source building energy modeling platform (OpenStudio and EnergyPlus) with the long-term goal of supporting the design and optimization of energy districts.« less

An energy harvesting solution based on the post-buckling response of non-prismatic slender beams

NASA Astrophysics Data System (ADS)

Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Alavi, Amir H.; Lajnef, Nizar

2017-04-01

Systems based on post-buckled structural elements have been extensively used in many applications such as actuation, remote sensing and energy harvesting thanks to their efficiency enhancement. The post-buckling snap- through behavior of bilaterally constrained beams has been used to create an efficient energy harvesting mechanism under quasi-static excitations. The conversion mechanism has been used to transform low-rate and low-frequency excitations into high-rate motions. Electric energy can be generated from such high-rate motions using piezoelectric transducers. However, lack of control over the post-buckling behavior severely limits the mechanism's efficiency. This study aims to maximize the levels of the harvestable power by controlling the location of the snapping point along the beam at different buckling transitions. Since the snap-through location cannot be controlled by tuning the geometry properties of a uniform cross-section beam, non-uniform cross sections are examined. An energy-based theoretical model is herein developed to predict the post-buckling response of non-uniform cross-section beams. The total potential energy is minimized under constraints that represent the physical confinement of the beam between the lateral boundaries. Experimentally validated results show that changing the shape and geometry dimensions of non- uniform cross-section beams allows for the accurate control of the snap-through location at different buckling transitions. A 78.59% increase in harvested energy levels is achieved by optimizing the beam's shape.

Hierarchical fuzzy control of low-energy building systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Zhen; Dexter, Arthur

2010-04-15

A hierarchical fuzzy supervisory controller is described that is capable of optimizing the operation of a low-energy building, which uses solar energy to heat and cool its interior spaces. The highest level fuzzy rules choose the most appropriate set of lower level rules according to the weather and occupancy information; the second level fuzzy rules determine an optimal energy profile and the overall modes of operation of the heating, ventilating and air-conditioning system (HVAC); the third level fuzzy rules select the mode of operation of specific equipment, and assign schedules to the local controllers so that the optimal energy profilemore » can be achieved in the most efficient way. Computer simulation is used to compare the hierarchical fuzzy control scheme with a supervisory control scheme based on expert rules. The performance is evaluated by comparing the energy consumption and thermal comfort. (author)« less

Efficiency Goals

ERIC Educational Resources Information Center

Graham, Donald

2009-01-01

The lighting of learning environments is an important focus in designing new schools and renovating older schools. Studies long have shown that appropriate lighting levels and daylighting improve learning; now, climbing energy budgets have spurred school administrators to seek more efficient use of lighting. Electricity rates are expected to rise…

The Energy Budget at the Earth’s Surface: Photosynthesis Under Field Condition: Solar Radiation Balance and Photosynthetic Efficiency.

DTIC Science & Technology

40-cm level in corn that is 300 cm high. Calculations indicate maximum thermal efficiency of photosynthesis under the experimental conditions to be 40 percent of the yield obtained from laboratory grown chlorella . (Author)

Research on multi-level decision game strategy of electricity sales market considering ETS and block chain

NASA Astrophysics Data System (ADS)

Liu, Jinjie

2017-08-01

In order to fully consider the impact of future policies and technologies on the electricity sales market, improve the efficiency of electricity market operation, realize the dual goal of power reform and energy saving and emission reduction, this paper uses multi-level decision theory to put forward the double-layer game model under the consideration of ETS and block chain. We set the maximization of electricity sales profit as upper level objective and establish a game strategy model of electricity purchase; while we set maximization of user satisfaction as lower level objective and build a choice behavior model based on customer satisfaction. This paper applies the strategy to the simulation of a sales company's transaction, and makes a horizontal comparison of the same industry competitors as well as a longitudinal comparison of game strategies considering different factors. The results show that Double-layer game model is reasonable and effective, it can significantly improve the efficiency of the electricity sales companies and user satisfaction, while promoting new energy consumption and achieving energy-saving emission reduction.

RF rectifiers for EM power harvesting in a Deep Brain Stimulating device.

PubMed

Hosain, Md Kamal; Kouzani, Abbas Z; Tye, Susannah; Kaynak, Akif; Berk, Michael

2015-03-01

A passive deep brain stimulation (DBS) device can be equipped with a rectenna, consisting of an antenna and a rectifier, to harvest energy from electromagnetic fields for its operation. This paper presents optimization of radio frequency rectifier circuits for wireless energy harvesting in a passive head-mountable DBS device. The aim is to achieve a compact size, high conversion efficiency, and high output voltage rectifier. Four different rectifiers based on the Delon doubler, Greinacher voltage tripler, Delon voltage quadrupler, and 2-stage charge pumped architectures are designed, simulated, fabricated, and evaluated. The design and simulation are conducted using Agilent Genesys at operating frequency of 915 MHz. A dielectric substrate of FR-4 with thickness of 1.6 mm, and surface mount devices (SMD) components are used to fabricate the designed rectifiers. The performance of the fabricated rectifiers is evaluated using a 915 MHz radio frequency (RF) energy source. The maximum measured conversion efficiency of the Delon doubler, Greinacher tripler, Delon quadrupler, and 2-stage charge pumped rectifiers are 78, 75, 73, and 76 % at -5 dBm input power and for load resistances of 5-15 kΩ. The conversion efficiency of the rectifiers decreases significantly with the increase in the input power level. The Delon doubler rectifier provides the highest efficiency at both -5 and 5 dBm input power levels, whereas the Delon quadrupler rectifier gives the lowest efficiency for the same inputs. By considering both efficiency and DC output voltage, the charge pump rectifier outperforms the other three rectifiers. Accordingly, the optimised 2-stage charge pumped rectifier is used together with an antenna to harvest energy in our DBS device.

Engineering Strategies and Methods for Avoiding Air-Quality Externalities: Dispersion Modeling, Home Energy Conservation, and Scenario Planning

NASA Astrophysics Data System (ADS)

Knox, Andrew James

Energy conservation can improve air quality by reducing emissions from fuel combustion. The human health value retained through better air quality can then offset the cost of energy conservation. Through this thesis' innovative yet widely-accessible combination of air pollution dispersion modeling and atmospheric chemistry, it is estimated that the health value retained by avoiding emissions from Ontario's former coal-fired generating stations is 5.74/MWh (using an upper-bound value of 265,000 per year of life lost). This value is combined with energy modeling of homes in the first-ever assessment of the air-quality health benefits of low-energy buildings. It is shown that avoided health damages can equal 7% of additional construction costs of energy efficient buildings in Ontario. At 7%, health savings are a significant item in the cost analysis of efficient buildings. Looking to energy efficiency in the context of likely future low-resource natural gas scenarios, building efficient buildings today is shown to be more economically efficient than any building retrofit option. Considering future natural gas scarcity in the context of Ontario's Long-Term Energy Plan reveals that Ontario may be forced to return to coal-fired electricity. Projected coal use would result in externalities greater than $600 million/year; 80% more than air-quality externalities from Ontario's electricity in 1985. Radically aggressive investment in electricity conservation (75% reduction per capita by 2075) is one promising path forward that keeps air-quality externalities below 1985 levels. Non-health externalities are an additional concern, the quantification, and ultimately monetization, of which could be practical using emerging air pollution monitoring technologies. Energy, conservation, energy planning, and energy's externalities form a complex situation in which today's decisions are critical to a successful future. It is clear that reducing the demand for energy is essential and that there are economically efficient conservation opportunities, particularly in the building sector, being missed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desroches, Louis-Benoit; Garbesi, Karina

It is well established that energy efficiency is most often the lowest cost approach to reducing national energy use and minimizing carbon emissions. National investments in energy efficiency to date have been highly cost-effective. The cumulative impacts (out to 2050) of residential energy efficiency standards are expected to have a benefit-to-cost ratio of 2.71:1. This project examined energy end-uses in the residential, commercial, and in some cases the industrial sectors. The scope is limited to appliances and equipment, and does not include building materials, building envelopes, and system designs. This scope is consistent with the scope of DOE's appliance standardsmore » program, although many products considered here are not currently subject to energy efficiency standards. How much energy could the United States save if the most efficient design options currently feasible were adopted universally? What design features could produce those savings? How would the savings from various technologies compare? With an eye toward identifying promising candidates and strategies for potential energy efficiency standards, the Max Tech and Beyond project aims to answer these questions. The analysis attempts to consolidate, in one document, the energy savings potential and design characteristics of best-on-market products, best-engineered products (i.e., hypothetical products produced using best-on-market components and technologies), and emerging technologies in research & development. As defined here, emerging technologies are fundamentally new and are as yet unproven in the market, although laboratory studies and/or emerging niche applications offer persuasive evidence of major energy-savings potential. The term 'max tech' is used to describe both best-engineered and emerging technologies (whichever appears to offer larger savings). Few best-on-market products currently qualify as max tech, since few apply all available best practices and components. The three primary analyses presented in this report are: Nevertheless, it is important to analyze best-on-market products, since data on truly max tech technologies are limited. (1) an analysis of the cross-cutting strategies most promising for reducing appliance and equipment energy use in the U.S.; (2) a macro-analysis of the U.S. energy-saving potential inherent in promising ultra-efficient appliance technologies; and (3) a product-level analysis of the energy-saving potential.« less

Solar-pumped electronic-to-vibrational energy transfer lasers

NASA Technical Reports Server (NTRS)

Harries, W. L.; Wilson, J. W.

1981-01-01

The possibility of using solar-pumped lasers as solar energy converters is examined. The absorbing media considered are halogens or halogen compounds, which are dissociated to yield excited atoms, which then hand over energy to a molecular lasing medium. Estimates of the temperature effects for a Br2-CO2-He system with He as the cooling gas are given. High temperatures can cause the lower energy levels of the CO2 laser transition to be filled. The inverted populations are calculated and lasing should be possible. However, the efficiency is less than 0.001. Examination of other halogen-molecular lasant combinations (where the rate coefficients are known) indicate efficiencies in all cases of less than 0.005.

Similarity criteria in calculations of the energy characteristics of a cw oxygen - iodine laser

NASA Astrophysics Data System (ADS)

Mezhenin, A. V.; Azyazov, V. N.

2012-12-01

The calculated and experimental data on the energy efficiency of a cw oxygen - iodine laser (OIL) are analysed based on two similarity criteria, namely, on the ratio of the residence time of the gas mixture in the resonator to the characteristic time of extraction of the energy stored in singlet oxygen td and on the gain-to-loss ratio Π. It is shown that the simplified two-level laser model satisfactorily predicts the output characteristics of OILs with a stable resonator at τd <= 7. Efficient energy extraction from the OIL active medium is achieved in the case of τd = 5 - 7, Π = 4 - 8.

Residential energy use and conservation in Venezuela: Results and implications of a household survey in Caracas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Figueroa, M.J.; Ketoff, A.; Masera, O.

1992-10-01

This document presents the final report of a study of residential energy use in Caracas, the capital of Venezuela. It contains the findings of a household energy-use survey held in Caracas in 1988 and examines options for introducing energy conservation measures in the Venezuelan residential sector. Oil exports form the backbone of the Venezuelan economy. Improving energy efficiency in Venezuela will help free domestic oil resources that can be sold to the rest of the world. Energy conservation will also contribute to a faster recovery of the economy by reducing the need for major investments in new energy facilities, allowingmore » the Venezuelan government to direct its financial investments towards other areas of development. Local environmental benefits will constitute an important additional by-product of implementing energy-efficiency policies in Venezuela. Caracas`s residential sector shows great potential for energy conservation. The sector is characterized by high saturation levels of major appliances, inefficiency of appliances available in the market, and by careless patterns of energy use. Household energy use per capita average 6.5 GJ/per year which is higher than most cities in developing countries; most of this energy is used for cooking. Electricity accounts for 41% of all energy use, while LPG and natural gas constitute the remainder. Specific options for inducing energy conservation and energy efficiency in Caracas`s residential sector include energy-pricing policies, fuel switching, particularly from electricity to gas, improving the energy performance of new appliances and customer information. To ensure the accomplishment of an energy-efficiency strategy, a concerted effort by energy users, manufacturers, utility companies, government agencies, and research institutions will be needed.« less

Investigation of the charge boost technology for the efficiency increase of closed sorption thermal energy storage systems

NASA Astrophysics Data System (ADS)

Rohringer, C.; Engel, G.; Köll, R.; Wagner, W.; van Helden, W.

2017-10-01

The inclusion of solar thermal energy into energy systems requires storage possibilities to overcome the gap between supply and demand. Storage of thermal energy with closed sorption thermal energy systems has the advantage of low thermal losses and high energy density. However, the efficiency of these systems needs yet to be increased to become competitive on the market. In this paper, the so-called “charge boost technology” is developed and tested via experiments as a new concept for the efficiency increase of compact thermal energy storages. The main benefit of the charge boost technology is that it can reach a defined state of charge for sorption thermal energy storages at lower temperature levels than classic pure desorption processes. Experiments are conducted to provide a proof of principle for this concept. The results show that the charge boost technology does function as predicted and is a viable option for further improvement of sorption thermal energy storages. Subsequently, a new process application is developed by the author with strong focus on the utilization of the advantages of the charge boost technology over conventional desorption processes. After completion of the conceptual design, the theoretical calculations are validated via experiments.

Hexaazatrinaphthylene derivatives: Efficient electron-transporting materials with tunable energy levels for inverted perovskite solar cells

DOE PAGES

Zhao, Dongbing; Zhu, Zonglong; Kuo, Ming -Yu; ...

2016-06-08

Hexaazatrinaphthylene (HATNA) derivatives have been successfully shown to function as efficient electron-transporting materials (ETMs) for perovskite solar cells (PVSCs). The cells demonstrate a superior power conversion efficiency (PCE) of 17.6% with negligible hysteresis. Furthermore, this study provides one of the first nonfullerene small-moleculebased ETMs for high-performance p–i–n PVSCs.

Blood flow dynamic improvement with aneurysm repair detected by a patient-specific model of multiple aortic aneurysms.

PubMed

Sughimoto, Koichi; Takahara, Yoshiharu; Mogi, Kenji; Yamazaki, Kenji; Tsubota, Ken'ichi; Liang, Fuyou; Liu, Hao

2014-05-01

Aortic aneurysms may cause the turbulence of blood flow and result in the energy loss of the blood flow, while grafting of the dilated aorta may ameliorate these hemodynamic disturbances, contributing to the alleviation of the energy efficiency of blood flow delivery. However, evaluating of the energy efficiency of blood flow in an aortic aneurysm has been technically difficult to estimate and not comprehensively understood yet. We devised a multiscale computational biomechanical model, introducing novel flow indices, to investigate a single male patient with multiple aortic aneurysms. Preoperative levels of wall shear stress and oscillatory shear index (OSI) were elevated but declined after staged grafting procedures: OSI decreased from 0.280 to 0.257 (first operation) and 0.221 (second operation). Graftings may strategically counter the loss of efficient blood delivery to improve hemodynamics of the aorta. The energy efficiency of blood flow also improved postoperatively. Novel indices of pulsatile pressure index (PPI) and pulsatile energy loss index (PELI) were evaluated to characterize and quantify energy loss of pulsatile blood flow. Mean PPI decreased from 0.445 to 0.423 (first operation) and 0.359 (second operation), respectively; while the preoperative PELI of 0.986 dropped to 0.820 and 0.831. Graftings contributed not only to ameliorate wall shear stress or oscillatory shear index but also to improve efficient blood flow. This patient-specific modeling will help in analyzing the mechanism of aortic aneurysm formation and may play an important role in quantifying the energy efficiency or loss in blood delivery.

Conceptual study of superconducting urban area power systems

NASA Astrophysics Data System (ADS)

Noe, Mathias; Bach, Robert; Prusseit, Werner; Willén, Dag; Gold-acker, Wilfried; Poelchau, Juri; Linke, Christian

2010-06-01

Efficient transmission, distribution and usage of electricity are fundamental requirements for providing citizens, societies and economies with essential energy resources. It will be a major future challenge to integrate more sustainable generation resources, to meet growing electricity demand and to renew electricity networks. Research and development on superconducting equipment and components have an important role to play in addressing these challenges. Up to now, most studies on superconducting applications in power systems have been concentrated on the application of specific devices like for example cables and current limiters. In contrast to this, the main focus of our study is to show the consequence of a large scale integration of superconducting power equipment in distribution level urban power systems. Specific objectives are to summarize the state-of-the-art of superconducting power equipment including cooling systems and to compare the superconducting power system with respect to energy and economic efficiency with conventional solutions. Several scenarios were considered starting from the replacement of an existing distribution level sub-grid up to a full superconducting urban area distribution level power system. One major result is that a full superconducting urban area distribution level power system could be cost competitive with existing solutions in the future. In addition to that, superconducting power systems offer higher energy efficiency as well as a number of technical advantages like lower voltage drops and improved stability.

A 60 GOPS/W, -1.8 V to 0.9 V body bias ULP cluster in 28 nm UTBB FD-SOI technology

NASA Astrophysics Data System (ADS)

Rossi, Davide; Pullini, Antonio; Loi, Igor; Gautschi, Michael; Gürkaynak, Frank K.; Bartolini, Andrea; Flatresse, Philippe; Benini, Luca

2016-03-01

Ultra-low power operation and extreme energy efficiency are strong requirements for a number of high-growth application areas, such as E-health, Internet of Things, and wearable Human-Computer Interfaces. A promising approach to achieve up to one order of magnitude of improvement in energy efficiency over current generation of integrated circuits is near-threshold computing. However, frequency degradation due to aggressive voltage scaling may not be acceptable across all performance-constrained applications. Thread-level parallelism over multiple cores can be used to overcome the performance degradation at low voltage. Moreover, enabling the processors to operate on-demand and over a wide supply voltage and body bias ranges allows to achieve the best possible energy efficiency while satisfying a large spectrum of computational demands. In this work we present the first ever implementation of a 4-core cluster fabricated using conventional-well 28 nm UTBB FD-SOI technology. The multi-core architecture we present in this work is able to operate on a wide range of supply voltages starting from 0.44 V to 1.2 V. In addition, the architecture allows a wide range of body bias to be applied from -1.8 V to 0.9 V. The peak energy efficiency 60 GOPS/W is achieved at 0.5 V supply voltage and 0.5 V forward body bias. Thanks to the extended body bias range of conventional-well FD-SOI technology, high energy efficiency can be guaranteed for a wide range of process and environmental conditions. We demonstrate the ability to compensate for up to 99.7% of chips for process variation with only ±0.2 V of body biasing, and compensate temperature variation in the range -40 °C to 120 °C exploiting -1.1 V to 0.8 V body biasing. When compared to leading-edge near-threshold RISC processors optimized for extremely low power applications, the multi-core architecture we propose has 144× more performance at comparable energy efficiency levels. Even when compared to other low-power processors with comparable performance, including those implemented in 28 nm technology, our platform provides 1.4× to 3.7× better energy efficiency.

MIROS: A Hybrid Real-Time Energy-Efficient Operating System for the Resource-Constrained Wireless Sensor Nodes

PubMed Central

Liu, Xing; Hou, Kun Mean; de Vaulx, Christophe; Shi, Hongling; Gholami, Khalid El

2014-01-01

Operating system (OS) technology is significant for the proliferation of the wireless sensor network (WSN). With an outstanding OS; the constrained WSN resources (processor; memory and energy) can be utilized efficiently. Moreover; the user application development can be served soundly. In this article; a new hybrid; real-time; memory-efficient; energy-efficient; user-friendly and fault-tolerant WSN OS MIROS is designed and implemented. MIROS implements the hybrid scheduler and the dynamic memory allocator. Real-time scheduling can thus be achieved with low memory consumption. In addition; it implements a mid-layer software EMIDE (Efficient Mid-layer Software for User-Friendly Application Development Environment) to decouple the WSN application from the low-level system. The application programming process can consequently be simplified and the application reprogramming performance improved. Moreover; it combines both the software and the multi-core hardware techniques to conserve the energy resources; improve the node reliability; as well as achieve a new debugging method. To evaluate the performance of MIROS; it is compared with the other WSN OSes (TinyOS; Contiki; SOS; openWSN and mantisOS) from different OS concerns. The final evaluation results prove that MIROS is suitable to be used even on the tight resource-constrained WSN nodes. It can support the real-time WSN applications. Furthermore; it is energy efficient; user friendly and fault tolerant. PMID:25248069

MIROS: a hybrid real-time energy-efficient operating system for the resource-constrained wireless sensor nodes.

PubMed

Liu, Xing; Hou, Kun Mean; de Vaulx, Christophe; Shi, Hongling; El Gholami, Khalid

2014-09-22

Operating system (OS) technology is significant for the proliferation of the wireless sensor network (WSN). With an outstanding OS; the constrained WSN resources (processor; memory and energy) can be utilized efficiently. Moreover; the user application development can be served soundly. In this article; a new hybrid; real-time; memory-efficient; energy-efficient; user-friendly and fault-tolerant WSN OS MIROS is designed and implemented. MIROS implements the hybrid scheduler and the dynamic memory allocator. Real-time scheduling can thus be achieved with low memory consumption. In addition; it implements a mid-layer software EMIDE (Efficient Mid-layer Software for User-Friendly Application Development Environment) to decouple the WSN application from the low-level system. The application programming process can consequently be simplified and the application reprogramming performance improved. Moreover; it combines both the software and the multi-core hardware techniques to conserve the energy resources; improve the node reliability; as well as achieve a new debugging method. To evaluate the performance of MIROS; it is compared with the other WSN OSes (TinyOS; Contiki; SOS; openWSN and mantisOS) from different OS concerns. The final evaluation results prove that MIROS is suitable to be used even on the tight resource-constrained WSN nodes. It can support the real-time WSN applications. Furthermore; it is energy efficient; user friendly and fault tolerant.

Neighborhood Energy/Economic Development project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-12-31

Energy costs impact low income communities more than anyone else. Low income residents pay a larger percentage of their incomes for energy costs. In addition, they generally have far less discretionary energy use to eliminate in response to increasing energy prices. Furthermore, with less discretionary income, home energy efficiency improvements are often too expensive. Small neighborhood businesses are in the same situation. Improved efficiency in the use of energy can improve this situation by reducing energy costs for residents and local businesses. More importantly, energy management programs can increase the demand for local goods and services and lead to themore » creation of new job training and employment opportunities. In this way, neighborhood based energy efficiency programs can support community economic development. The present project, undertaken with the support of the Urban Consortium Energy Task Force, was intended to serve as a demonstration of energy/economic programming at the neighborhood level. The San Francisco Neighborhood Energy/Economic Development (NEED) project was designed to be a visible demonstration of bringing the economic development benefits of energy management home to low-income community members who need it most. To begin, a Community Advisory Committee was established to guide the design of the programs to best meet needs of the community. Subsequently three neighborhood energy/economic development programs were developed: The small business energy assistance program; The youth training and weatherization program; and, The energy review of proposed housing development projects.« less

Fine-Tuning the Energy Levels of a Nonfullerene Small-Molecule Acceptor to Achieve a High Short-Circuit Current and a Power Conversion Efficiency over 12% in Organic Solar Cells.

PubMed

Kan, Bin; Zhang, Jiangbin; Liu, Feng; Wan, Xiangjian; Li, Chenxi; Ke, Xin; Wang, Yunchuang; Feng, Huanran; Zhang, Yamin; Long, Guankui; Friend, Richard H; Bakulin, Artem A; Chen, Yongsheng

2018-01-01

Organic solar cell optimization requires careful balancing of current-voltage output of the materials system. Here, such optimization using ultrafast spectroscopy as a tool to optimize the material bandgap without altering ultrafast photophysics is reported. A new acceptor-donor-acceptor (A-D-A)-type small-molecule acceptor NCBDT is designed by modification of the D and A units of NFBDT. Compared to NFBDT, NCBDT exhibits upshifted highest occupied molecular orbital (HOMO) energy level mainly due to the additional octyl on the D unit and downshifted lowest unoccupied molecular orbital (LUMO) energy level due to the fluorination of A units. NCBDT has a low optical bandgap of 1.45 eV which extends the absorption range toward near-IR region, down to ≈860 nm. However, the 60 meV lowered LUMO level of NCBDT hardly changes the V oc level, and the elevation of the NCBDT HOMO does not have a substantial influence on the photophysics of the materials. Thus, for both NCBDT- and NFBDT-based systems, an unusually slow (≈400 ps) but ultimately efficient charge generation mediated by interfacial charge-pair states is observed, followed by effective charge extraction. As a result, the PBDB-T:NCBDT devices demonstrate an impressive power conversion efficiency over 12%-among the best for solution-processed organic solar cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiscale Quantum Mechanics/Molecular Mechanics Simulations with Neural Networks.

PubMed

Shen, Lin; Wu, Jingheng; Yang, Weitao

2016-10-11

Molecular dynamics simulation with multiscale quantum mechanics/molecular mechanics (QM/MM) methods is a very powerful tool for understanding the mechanism of chemical and biological processes in solution or enzymes. However, its computational cost can be too high for many biochemical systems because of the large number of ab initio QM calculations. Semiempirical QM/MM simulations have much higher efficiency. Its accuracy can be improved with a correction to reach the ab initio QM/MM level. The computational cost on the ab initio calculation for the correction determines the efficiency. In this paper we developed a neural network method for QM/MM calculation as an extension of the neural-network representation reported by Behler and Parrinello. With this approach, the potential energy of any configuration along the reaction path for a given QM/MM system can be predicted at the ab initio QM/MM level based on the semiempirical QM/MM simulations. We further applied this method to three reactions in water to calculate the free energy changes. The free-energy profile obtained from the semiempirical QM/MM simulation is corrected to the ab initio QM/MM level with the potential energies predicted with the constructed neural network. The results are in excellent accordance with the reference data that are obtained from the ab initio QM/MM molecular dynamics simulation or corrected with direct ab initio QM/MM potential energies. Compared with the correction using direct ab initio QM/MM potential energies, our method shows a speed-up of 1 or 2 orders of magnitude. It demonstrates that the neural network method combined with the semiempirical QM/MM calculation can be an efficient and reliable strategy for chemical reaction simulations.

Urban sustainable energy development: A case study of the city of Philadelphia

NASA Astrophysics Data System (ADS)

Argyriou, Iraklis

This study explores the role of cities in sustainable energy development through a governance-informed analysis. Despite the leading position of municipalities in energy sustainability, cities have been mostly conceptualized as sites where energy development is shaped by external policy scales, i.e. the national level. A growing body of research, however, critiques this analytical perspective, and seeks to better understand the type of factors and dynamics that influence energy sustainability within a multi-level policy context for urban energy. Given that particular circumstances are applicable across cities, a context-specific analysis can provide insight regarding how sustainable energy development takes place in urban areas. In applying such an analytical perspective on urban energy sustainability, this study undertakes a qualitative case study analysis for the city of Philadelphia, Pennsylvania, by looking at four key local policy initiatives relevant to building energy efficiency and solar electricity development at the municipal government and city-wide level. The evaluation of the initiatives suggests that renewable electricity use has increased substantially in the city over the last years but the installed capacity of local renewable electricity systems, including solar photovoltaics, is low. On the other hand, although the city has made little progress in meeting its building energy efficiency targets, more comprehensive action is taken in this area. The study finds that the above outcomes have been shaped mainly by four factors. The first is the city government's incremental policy approach aiming to develop a facilitative context for local action. The second is the role that a diverse set of stakeholders have in local sustainable energy development. The third is the constraints that systemic policy barriers create for solar power development. The fourth is the ways through which the relevant multi-level policy environment structures the city's possibilities on sustainable energy. In this context, the study identifies four areas of policy recommendation that could enhance Philadelphia's prospects for energy sustainability: integrated municipal energy planning; stable financing for market development; enhanced actor interactions; and multi-level policymaking that facilitates local action. These policy directions could be of interest to a broader body of metropolitan cities regarding their efforts in sustainable energy development.

Real-time Data Center Energy Efficiency At Pacific Northwest National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisk, Daniel R.; Khaleel, Mohammad A.; Marquez, Andres

2009-05-26

The escalating consumption of power in data centers worldwide has brought the issue of data center energy efficiency to the forefront. Data center owners and operators now regard detailed knowledge of the energy efficiencies of their data centers as a competitive advantage. With funding from the Department of Energy (NNSA), PNNL has undertaken an in-depth analysis of the real-time energy efficiency for its Energy Smart Data Center Test Bed(ESDC-TB), which is housed in the mixed-use EMSL. The analysis is centered around the real-time display of The Green Grid’s proposed DCiE metric. To calculate this metric, PNNL relies on a varietymore » of sources of data. At the ESDC-TB level, the data center is instrumented to the 100% level (all power consumption, and water temperatures and flow rates are measured). Most of this data is monitored in real-time, but the exception to this is with the CRAHs, which rely on a one-time power consumption measurement for the blowers (these are single speed blowers, so a one-time measurement suffices.). Outside of the data center (EMSL facility level), PNNL relies on the following: • Real-time data from the entire chiller plant (five chillers), six chilled water pumps, and one of four cooling towers (blowers only). • One-time power measurements for a single fixed speed pump that is representative of each grouping of pumps (the other pumps are assumed to possess the same power consumption levels). • One-time power measurements for a single two-speed cooling tower blower. This same blower model is deployed in three of the four cooling towers, so is assumed to be representative for all these blowers. • One-time power measurements for a single fixed speed cooling tower pump. This same pump model is deployed in all four cooling towers, so is assumed to be representative for all these pumps. A software tool named FRED was developed by PNNL to acquire, reduce, display, and archive all the data acquired from the ESDC-TB and EMSL. FRED provides the ability to display various levels of real-time data starting at the ESDC-TB and EMSL levels, then to lower levels as desired. For example, for the ESDC-TB, graphical screens are provided at the data center level, the rack level, the server level, and even the component level. In the near-term, FRED will also display the real-time DCiE. One of the major challenges to doing this in a mixed-use facility has been to quantify the power consumption of each major mechanical or electrical subsystem that is attributable to the IT equipment housed within the ESDC-TB (i.e., NW-ICE). PNNL has tackled this issue for its five chiller plant, and the analysis is presented in the paper. The analysis for all the remaining mechanical and electrical subsystems is now underway and will be presented in future publications.« less

Energy Awareness and Scheduling in Mobile Devices and High End Computing

ERIC Educational Resources Information Center

Pawaskar, Sachin S.

2013-01-01

In the context of the big picture as energy demands rise due to growing economies and growing populations, there will be greater emphasis on sustainable supply, conservation, and efficient usage of this vital resource. Even at a smaller level, the need for minimizing energy consumption continues to be compelling in embedded, mobile, and server…

Zero Energy Schools--Beyond Platinum

ERIC Educational Resources Information Center

Hutton, Paul C.

2011-01-01

One of the fastest growing trends in school design is Net Zero Energy Schools. There are now at least a dozen or more schools completed or in construction that have achieved, or have committed to, this incredible level of energy efficiency. In this article, the author examines this trend and take a brief look at some of the exemplary projects that…

Comparing Server Energy Use and Efficiency Using Small Sample Sizes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coles, Henry C.; Qin, Yong; Price, Phillip N.

This report documents a demonstration that compared the energy consumption and efficiency of a limited sample size of server-type IT equipment from different manufacturers by measuring power at the server power supply power cords. The results are specific to the equipment and methods used. However, it is hoped that those responsible for IT equipment selection can used the methods described to choose models that optimize energy use efficiency. The demonstration was conducted in a data center at Lawrence Berkeley National Laboratory in Berkeley, California. It was performed with five servers of similar mechanical and electronic specifications; three from Intel andmore » one each from Dell and Supermicro. Server IT equipment is constructed using commodity components, server manufacturer-designed assemblies, and control systems. Server compute efficiency is constrained by the commodity component specifications and integration requirements. The design freedom, outside of the commodity component constraints, provides room for the manufacturer to offer a product with competitive efficiency that meets market needs at a compelling price. A goal of the demonstration was to compare and quantify the server efficiency for three different brands. The efficiency is defined as the average compute rate (computations per unit of time) divided by the average energy consumption rate. The research team used an industry standard benchmark software package to provide a repeatable software load to obtain the compute rate and provide a variety of power consumption levels. Energy use when the servers were in an idle state (not providing computing work) were also measured. At high server compute loads, all brands, using the same key components (processors and memory), had similar results; therefore, from these results, it could not be concluded that one brand is more efficient than the other brands. The test results show that the power consumption variability caused by the key components as a group is similar to all other components as a group. However, some differences were observed. The Supermicro server used 27 percent more power at idle compared to the other brands. The Intel server had a power supply control feature called cold redundancy, and the data suggest that cold redundancy can provide energy savings at low power levels. Test and evaluation methods that might be used by others having limited resources for IT equipment evaluation are explained in the report.« less

Energy Level Tuning of Poly(phenylene-alt-dithienobenzothiadiazole)s for Low Photon Energy Loss Solar Cells.

PubMed

Heuvel, Ruurd; van Franeker, Jacobus J; Janssen, René A J

2017-03-01

Six poly(phenylene- alt -dithienobenzothiadiazole)-based polymers have been synthesized for application in polymer-fullerene solar cells. Hydrogen, fluorine, or nitrile substitution on benzo-thiadiazole and alkoxy or ester substitution on the phenylene moiety are investigated to reduce the energy loss per converted photon. Power conversion efficiencies (PCEs) up to 6.6% have been obtained. The best performance is found for the polymer-fullerene combination with distinct phase separation and crystalline domains. This improves the maximum external quantum efficiency for charge formation and collection to 66%. The resulting higher photocurrent compensates for the relatively large energy loss per photon ( E loss = 0.97 eV) in achieving a high PCE. By contrast, the poly-mer that provides a reduced energy loss ( E loss = 0.49 eV) gives a lower photocurrent and a reduced PCE of 1.8% because the external quantum efficiency of 17% is limited by a suboptimal morphology and a reduced driving force for charge transfer.

Global map of solar power production efficiency, considering micro climate factors

NASA Astrophysics Data System (ADS)

Hassanpour Adeh, E.; Higgins, C. W.

2017-12-01

Natural resources degradation and greenhouse gas emissions are creating a global crisis. Renewable energy is the most reliable option to mitigate this environmental dilemma. Abundancy of solar energy makes it highly attractive source of electricity. The existing global spatial maps of available solar energy are created with various models which consider the irradiation, latitude, cloud cover, elevation, shading and aerosols, and neglect the influence of local meteorological conditions. In this research, the influences of microclimatological variables on solar energy productivity were investigated with an in-field study at the Rabbit Hills solar arrays near Oregon State University. The local studies were extended to a global level, where global maps of solar power were produced, taking the micro climate variables into account. These variables included: temperature, relative humidity, wind speed, wind direction, solar radiation. The energy balance approach was used to synthesize the data and compute the efficiencies. The results confirmed that the solar power efficiency can be directly affected by the air temperature and wind speed.

Recent advances in efficient long-life, eye-safe solid state and CO2 lasers for laser radar applications

NASA Technical Reports Server (NTRS)

Hess, R. V.; Buoncristiani, A. M.; Brockman, P.; Bair, C. H.; Schryer, D. R.; Upchurch, B. T.; Wood, G. M.

1989-01-01

The key problems in the development of eye-safe solid-state lasers are discussed, taking into account the energy transfer mechanisms between the complicated energy level manifolds of the Tm, Ho, Er ion dopants in hosts with decreasing crystal fields such as YAG or YLF. Optimization of energy transfer for efficient lasing through choice of dopant concentration, power density, crystal field and temperature is addressed. The tailoring of energy transfer times to provide efficient energy extraction for short pulses used in DIAL and Doppler lidar is considered. Recent advances in Pt/SnO2 oxide catalysts and other noble metal/metal oxide combinations for CO2 lasers are discussed. Emphasis is given to the dramatic effects of small quantities of H2O vapor for increasing the activity and lifetime of Pt/SnO2 catalysts and to increased lifetime operation with rare isotope (C-12)(O-18)2 lasing mixtures.

Review of Evaluation, Measurement and Verification Approaches Used to Estimate the Load Impacts and Effectiveness of Energy Efficiency Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Messenger, Mike; Bharvirkar, Ranjit; Golemboski, Bill

Public and private funding for end-use energy efficiency actions is expected to increase significantly in the United States over the next decade. For example, Barbose et al (2009) estimate that spending on ratepayer-funded energy efficiency programs in the U.S. could increase frommore » $3.1 billion in 2008 to $$7.5 and 12.4 billion by 2020 under their medium and high scenarios. This increase in spending could yield annual electric energy savings ranging from 0.58% - 0.93% of total U.S. retail sales in 2020, up from 0.34% of retail sales in 2008. Interest in and support for energy efficiency has broadened among national and state policymakers. Prominent examples include {approx}$$18 billion in new funding for energy efficiency programs (e.g., State Energy Program, Weatherization, and Energy Efficiency and Conservation Block Grants) in the 2009 American Recovery and Reinvestment Act (ARRA). Increased funding for energy efficiency should result in more benefits as well as more scrutiny of these results. As energy efficiency becomes a more prominent component of the U.S. national energy strategy and policies, assessing the effectiveness and energy saving impacts of energy efficiency programs is likely to become increasingly important for policymakers and private and public funders of efficiency actions. Thus, it is critical that evaluation, measurement, and verification (EM&V) is carried out effectively and efficiently, which implies that: (1) Effective program evaluation, measurement, and verification (EM&V) methodologies and tools are available to key stakeholders (e.g., regulatory agencies, program administrators, consumers, and evaluation consultants); and (2) Capacity (people and infrastructure resources) is available to conduct EM&V activities and report results in ways that support program improvement and provide data that reliably compares achieved results against goals and similar programs in other jurisdictions (benchmarking). The National Action Plan for Energy Efficiency (2007) presented commonly used definitions for EM&V in the context of energy efficiency programs: (1) Evaluation (E) - The performance of studies and activities aimed at determining the effects and effectiveness of EE programs; (2) Measurement and Verification (M&V) - Data collection, monitoring, and analysis associated with the calculation of gross energy and demand savings from individual measures, sites or projects. M&V can be a subset of program evaluation; and (3) Evaluation, Measurement, and Verification (EM&V) - This term is frequently seen in evaluation literature. EM&V is a catchall acronym for determining both the effectiveness of program designs and estimates of load impacts at the portfolio, program and project level. This report is a scoping study that assesses current practices and methods in the evaluation, measurement and verification (EM&V) of ratepayer-funded energy efficiency programs, with a focus on methods and practices currently used for determining whether projected (ex-ante) energy and demand savings have been achieved (ex-post). M&V practices for privately-funded energy efficiency projects (e.g., ESCO projects) or programs where the primary focus is greenhouse gas reductions were not part of the scope of this study. We identify and discuss key purposes and uses of current evaluations of end-use energy efficiency programs, methods used to evaluate these programs, processes used to determine those methods; and key issues that need to be addressed now and in the future, based on discussions with regulatory agencies, policymakers, program administrators, and evaluation practitioners in 14 states and national experts in the evaluation field. We also explore how EM&V may evolve in a future in which efficiency funding increases significantly, innovative mechanisms for rewarding program performance are adopted, the role of efficiency in greenhouse gas mitigation is more closely linked, and programs are increasingly funded from multiple sources often with multiple program administrators and intended to meet multiple purposes.« less

An IoT-Based Solution for Monitoring a Fleet of Educational Buildings Focusing on Energy Efficiency.

PubMed

Amaxilatis, Dimitrios; Akrivopoulos, Orestis; Mylonas, Georgios; Chatzigiannakis, Ioannis

2017-10-10

Raising awareness among young people and changing their behaviour and habits concerning energy usage is key to achieving sustained energy saving. Additionally, young people are very sensitive to environmental protection so raising awareness among children is much easier than with any other group of citizens. This work examines ways to create an innovative Information & Communication Technologies (ICT) ecosystem (including web-based, mobile, social and sensing elements) tailored specifically for school environments, taking into account both the users (faculty, staff, students, parents) and school buildings, thus motivating and supporting young citizens' behavioural change to achieve greater energy efficiency. A mixture of open-source IoT hardware and proprietary platforms on the infrastructure level, are currently being utilized for monitoring a fleet of 18 educational buildings across 3 countries, comprising over 700 IoT monitoring points. Hereon presented is the system's high-level architecture, as well as several aspects of its implementation, related to the application domain of educational building monitoring and energy efficiency. The system is developed based on open-source technologies and services in order to make it capable of providing open IT-infrastructure and support from different commercial hardware/sensor vendors as well as open-source solutions. The system presented can be used to develop and offer new app-based solutions that can be used either for educational purposes or for managing the energy efficiency of the building. The system is replicable and adaptable to settings that may be different than the scenarios envisioned here (e.g., targeting different climate zones), different IT infrastructures and can be easily extended to accommodate integration with other systems. The overall performance of the system is evaluated in real-world environment in terms of scalability, responsiveness and simplicity.

Numerical Modeling and Testing of an Inductively-Driven and High-Energy Pulsed Plasma Thrusters

NASA Technical Reports Server (NTRS)

Parma, Brian

2004-01-01

Pulsed Plasma Thrusters (PPTs) are advanced electric space propulsion devices that are characterized by simplicity and robustness. They suffer, however, from low thrust efficiencies. This summer, two approaches to improve the thrust efficiency of PPTs will be investigated through both numerical modeling and experimental testing. The first approach, an inductively-driven PPT, uses a double-ignition circuit to fire two PPTs in succession. This effectively changes the PPTs configuration from an LRC circuit to an LR circuit. The LR circuit is expected to provide better impedance matching and improving the efficiency of the energy transfer to the plasma. An added benefit of the LR circuit is an exponential decay of the current, whereas a traditional PPT s under damped LRC circuit experiences the characteristic "ringing" of its current. The exponential decay may provide improved lifetime and sustained electromagnetic acceleration. The second approach, a high-energy PPT, is a traditional PPT with a variable size capacitor bank. This PPT will be simulated and tested at energy levels between 100 and 450 joules in order to investigate the relationship between efficiency and energy level. Arbitrary Coordinate Hydromagnetic (MACH2) code is used. The MACH2 code, designed by the Center for Plasma Theory and Computation at the Air Force Research Laboratory, has been used to gain insight into a variety of plasma problems, including electric plasma thrusters. The goals for this summer include numerical predictions of performance for both the inductively-driven PPT and high-energy PFT, experimental validation of the numerical models, and numerical optimization of the designs. These goals will be met through numerical and experimental investigation of the PPTs current waveforms, mass loss (or ablation), and impulse bit characteristics.

An IoT-Based Solution for Monitoring a Fleet of Educational Buildings Focusing on Energy Efficiency

PubMed Central

Akrivopoulos, Orestis

2017-01-01

Raising awareness among young people and changing their behaviour and habits concerning energy usage is key to achieving sustained energy saving. Additionally, young people are very sensitive to environmental protection so raising awareness among children is much easier than with any other group of citizens. This work examines ways to create an innovative Information & Communication Technologies (ICT) ecosystem (including web-based, mobile, social and sensing elements) tailored specifically for school environments, taking into account both the users (faculty, staff, students, parents) and school buildings, thus motivating and supporting young citizens’ behavioural change to achieve greater energy efficiency. A mixture of open-source IoT hardware and proprietary platforms on the infrastructure level, are currently being utilized for monitoring a fleet of 18 educational buildings across 3 countries, comprising over 700 IoT monitoring points. Hereon presented is the system’s high-level architecture, as well as several aspects of its implementation, related to the application domain of educational building monitoring and energy efficiency. The system is developed based on open-source technologies and services in order to make it capable of providing open IT-infrastructure and support from different commercial hardware/sensor vendors as well as open-source solutions. The system presented can be used to develop and offer new app-based solutions that can be used either for educational purposes or for managing the energy efficiency of the building. The system is replicable and adaptable to settings that may be different than the scenarios envisioned here (e.g., targeting different climate zones), different IT infrastructures and can be easily extended to accommodate integration with other systems. The overall performance of the system is evaluated in real-world environment in terms of scalability, responsiveness and simplicity. PMID:28994719

Direct work function measurement by gas phase photoelectron spectroscopy and its application on PbS nanoparticles.

PubMed

Axnanda, Stephanus; Scheele, Marcus; Crumlin, Ethan; Mao, Baohua; Chang, Rui; Rani, Sana; Faiz, Mohamed; Wang, Suidong; Alivisatos, A Paul; Liu, Zhi

2013-01-01

Work function is a fundamental property of a material's surface. It is playing an ever more important role in engineering new energy materials and efficient energy devices, especially in the field of photovoltaic devices, catalysis, semiconductor heterojunctions, nanotechnology, and electrochemistry. Using ambient pressure X-ray photoelectron spectroscopy (APXPS), we have measured the binding energies of core level photoelectrons of Ar gas in the vicinity of several reference materials with known work functions (Au(111), Pt(111), graphite) and PbS nanoparticles. We demonstrate an unambiguously negative correlation between the work functions of reference samples and the binding energies of Ar 2p core level photoelectrons detected from the Ar gas near the sample surface region. Using this experimentally determined linear relationship between the surface work function and Ar gas core level photoelectron binding energy, we can measure the surface work function of different materials under different gas environments. To demonstrate the potential applications of this ambient pressure XPS technique in nanotechnology and solar energy research, we investigate the work functions of PbS nanoparticles with various capping ligands: methoxide, mercaptopropionic acid, and ethanedithiol. Significant Fermi level position changes are observed for PbS nanoparticles when the nanoparticle size and capping ligands are varied. The corresponding changes in the valence band maximum illustrate that an efficient quantum dot solar cell design has to take into account the electrochemical effect of the capping ligand as well.

Effects of energy transfer on quantum efficiency of YAG:Nd

NASA Astrophysics Data System (ADS)

Lupei, V.; Lupei, A.; Georgescu, S.; Yen, W. M.

1989-10-01

Using the energy transfer parameters deduced from the study on nonexponential luminescence decay of the 4F3/2 level of Nd(3+) in YAG at room temperature, it is shown that up to 1.5 at. pct Nd, the relative quantum efficiency is reduced by an amount of 18.2C, C being the relative Nd concentration. It is pointed out that about 20 percent of this reduction is due to a very effective quenching mechanism inside the nearest-neighbor Nd-ion pairs.

Nanocrystal Size-Dependent Efficiency of Quantum Dot Sensitized Solar Cells in the Strongly Coupled CdSe Nanocrystals/TiO2 System.

PubMed

Yun, Hyeong Jin; Paik, Taejong; Diroll, Benjamin; Edley, Michael E; Baxter, Jason B; Murray, Christopher B

2016-06-15

Light absorption and electron injection are important criteria determining solar energy conversion efficiency. In this research, monodisperse CdSe quantum dots (QDs) are synthesized with five different diameters, and the size-dependent solar energy conversion efficiency of CdSe quantum dot sensitized solar cell (QDSSCs) is investigated by employing the atomic inorganic ligand, S(2-). Absorbance measurements and transmission electron microscopy show that the diameters of the uniform CdSe QDs are 2.5, 3.2, 4.2, 6.4, and 7.8 nm. Larger CdSe QDs generate a larger amount of charge under the irradiation of long wavelength photons, as verified by the absorbance results and the measurements of the external quantum efficiencies. However, the smaller QDs exhibit faster electron injection kinetics from CdSe QDs to TiO2 because of the high energy level of CBCdSe, as verified by time-resolved photoluminescence and internal quantum efficiency results. Importantly, the S(2-) ligand significantly enhances the electronic coupling between the CdSe QDs and TiO2, yielding an enhancement of the charge transfer rate at the interfacial region. As a result, the S(2-) ligand helps improve the new size-dependent solar energy conversion efficiency, showing best performance with 4.2-nm CdSe QDs, whereas conventional ligand, mercaptopropionic acid, does not show any differences in efficiency according to the size of the CdSe QDs. The findings reported herein suggest that the atomic inorganic ligand reinforces the influence of quantum confinement on the solar energy conversion efficiency of QDSSCs.

78 FR 20628 - Wireless Metering Challenge

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-05

... metering devices for use at the electrical panel level within commercial buildings. The specifications are intended to spur the development of new technologies in the wireless electric metering space. DATES... Technologies Office, Mailstop EE-2J, Office of Energy Efficiency and Renewable Energy, U.S. Department of...

Energy level and thickness control on PEDOT:PSS layer for efficient planar heterojunction perovskite cells

NASA Astrophysics Data System (ADS)

Wang, Chunhua; Zhang, Chujun; Tong, Sichao; Xia, Huayan; Wang, Lijuan; Xie, Haipeng; Gao, Yongli; Yang, Junliang

2018-01-01

Efficient planar heterojunction perovskite solar cells (PHJ-PSCs) with an architecture of ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/Al were fabricated by controlling the energy level and thickness of the PEDOT:PSS layer, where the PEDOT:PSS precursor was diluted with deionized water (H2O) and isopropyl alcohol (IPA), i.e. W-PEDOT:PSS and I-PEDOT:PSS. The performance parameters of the PHJ-PSCs showed soaring enhancement after employing W-PEDOT:PSS or I-PEDOT:PSS instead of pristine PEDOT:PSS (P-PEDOT:PSS), resulting in an increase of the power conversion efficiency (PCE) of W-PEDOT:PSS-based PHJ-PSCs to 15.60% from 11.95% for P-PEDOT:PSS-based PHJ-PSCs. The performance improvement results from two aspects. On the one hand, as compared to P-PEDOT:PSS, the occupied molecular orbital energy (HOMO) level of dilute PEDOT:PSS showed an impressive decrease and can well match the valence band of CH3NH3PbI3 film, resulting in less energy loss and a significant improvement in the open-circuit voltage (V oc). On the other hand, the dilute PEDOT:PSS could produce a thinner film as compared with the P-PEDOT:PSS, which also played an important role in the performance of the PHJ-PSCs. Furthermore, the electrochemical impedance spectroscopy (EIS) results indicated that the interface between perovskite and PEDOT:PSS was greatly improved by employing W-PEDOT:PSS or I-PEDOT:PSS, leading to an obvious decrease in the series resistance (R s) and an increase in the recombination resistance (R rec). The research demonstrated that diluting PEDOT:PSS with a common solvent, such as H2O and IPA, is a feasible low-temperature way of achieving efficient PHJ-PSCs.

Estimating Energy Consumption of Mobile Fluid Power in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynch, Lauren; Zigler, Bradley T.

This report estimates the market size and energy consumption of mobile off-road applications utilizing hydraulic fluid power, and summarizes technology gaps and implementation barriers. Mobile fluid power is the use of hydraulic fluids under pressure to transmit power in mobile equipment applications. The mobile off-road fluid power sector includes various uses of hydraulic fluid power equipment with fundamentally diverse end-use application and operational requirements, such as a skid steer loader, a wheel loader or an agriculture tractor. The agriculture and construction segments dominate the mobile off-road fluid power market in component unit sales volume. An estimated range of energy consumedmore » by the mobile off-road fluid power sector is 0.36 - 1.8 quads per year, which was 1.3 percent - 6.5 percent of the total energy consumed in 2016 by the transportation sector. Opportunities for efficiency improvements within the fluid power system result from needs to level and reduce the peak system load requirements and develop new technologies to reduce fluid power system level losses, both of which may be facilitated by characterizing duty cycles to define standardized performance test methods. There are currently no commonly accepted standardized test methods for evaluating equipment level efficiency over a duty cycle. The off-road transportation sector currently meets criteria emissions requirements, and there are no efficiency regulations requiring original equipment manufacturers (OEM) to invest in new architecture development to improve the fuel economy of mobile off-road fluid power systems. In addition, the end-user efficiency interests are outweighed by low equipment purchase or lease price concerns, required payback periods, and reliability and durability requirements of new architecture. Current economics, low market volumes with high product diversity, and regulation compliance challenge OEM investment in commercialization of new architecture development.« less

Real estate market and building energy performance: Data for a mass appraisal approach

PubMed Central

Bonifaci, Pietro; Copiello, Sergio

2015-01-01

Mass appraisal is widely considered an advanced frontier in the real estate valuation field. Performing mass appraisal entails the need to get access to base information conveyed by a large amount of transactions, such as prices and property features. Due to the lack of transparency of many Italian real estate market segments, our survey has been addressed to gather data from residential property advertisements. The dataset specifically focuses on property offer prices and dwelling energy efficiency. The latter refers to the label expressed and exhibited by the energy performance certificate. Moreover, data are georeferenced with the highest possible accuracy: at the neighborhood level for a 76.8% of cases, at street or building number level for the remaining 23.2%. Data are related to the analysis performed in Bonifaci and Copiello [1], about the relationship between house prices and building energy performance, that is to say, the willingness to pay in order to benefit from more efficient dwellings. PMID:26793751

Real estate market and building energy performance: Data for a mass appraisal approach.

PubMed

Bonifaci, Pietro; Copiello, Sergio

2015-12-01

Mass appraisal is widely considered an advanced frontier in the real estate valuation field. Performing mass appraisal entails the need to get access to base information conveyed by a large amount of transactions, such as prices and property features. Due to the lack of transparency of many Italian real estate market segments, our survey has been addressed to gather data from residential property advertisements. The dataset specifically focuses on property offer prices and dwelling energy efficiency. The latter refers to the label expressed and exhibited by the energy performance certificate. Moreover, data are georeferenced with the highest possible accuracy: at the neighborhood level for a 76.8% of cases, at street or building number level for the remaining 23.2%. Data are related to the analysis performed in Bonifaci and Copiello [1], about the relationship between house prices and building energy performance, that is to say, the willingness to pay in order to benefit from more efficient dwellings.

Energy efficiency as a unifying principle for human, environmental, and global health.

PubMed

Fontana, Luigi; Atella, Vincenzo; Kammen, Daniel M

2013-01-01

A strong analogy exists between over/under consumption of energy at the level of the human body and of the industrial metabolism of humanity. Both forms of energy consumption have profound implications for human, environmental, and global health. Globally, excessive fossil-fuel consumption, and individually, excessive food energy consumption are both responsible for a series of interrelated detrimental effects, including global warming, extreme weather conditions, damage to ecosystems, loss of biodiversity, widespread pollution, obesity, cancer, chronic respiratory disease, and other lethal chronic diseases. In contrast, data show that the efficient use of energy-in the form of food as well as fossil fuels and other resources-is vital for promoting human, environmental, and planetary health and sustainable economic development. While it is not new to highlight how efficient use of energy and food can address some of the key problems our world is facing, little research and no unifying framework exists to harmonize these concepts of sustainable system management across diverse scientific fields into a single theoretical body. Insights beyond reductionist views of efficiency are needed to encourage integrated changes in the use of the world's natural resources, with the aim of achieving a wiser use of energy, better farming systems, and healthier dietary habits. This perspective highlights a range of scientific-based opportunities for cost-effective pro-growth and pro-health policies while using less energy and natural resources.

Energy efficient engine high-pressure turbine component rig performance test report

NASA Technical Reports Server (NTRS)

Leach, K. P.

1983-01-01

A rig test of the cooled high-pressure turbine component for the Energy Efficient Engine was successfully completed. The principal objective of this test was to substantiate the turbine design point performance as well as determine off-design performance with the interaction of the secondary flow system. The measured efficiency of the cooled turbine component was 88.5 percent, which surpassed the rig design goal of 86.5 percent. The secondary flow system in the turbine performed according to the design intent. Characterization studies showed that secondary flow system performance is insensitive to flow and pressure variations. Overall, this test has demonstrated that a highly-loaded, transonic, single-stage turbine can achieve a high level of operating efficiency.

A review of technologies and performances of thermal treatment systems for energy recovery from waste.

PubMed

Lombardi, Lidia; Carnevale, Ennio; Corti, Andrea

2015-03-01

The aim of this work is to identify the current level of energy recovery through waste thermal treatment. The state of the art in energy recovery from waste was investigated, highlighting the differences for different types of thermal treatment, considering combustion/incineration, gasification and pyrolysis. Also different types of wastes - Municipal Solid Waste (MSW), Refuse Derived Fuel (RDF) or Solid Refuse Fuels (SRF) and some typologies of Industrial Waste (IW) (sludge, plastic scraps, etc.) - were included in the analysis. The investigation was carried out mainly reviewing papers, published in scientific journals and conferences, but also considering technical reports, to gather more information. In particular the goal of this review work was to synthesize studies in order to compare the values of energy conversion efficiencies measured or calculated for different types of thermal processes and different types of waste. It emerged that the dominant type of thermal treatment is incineration associated to energy recovery in a steam cycle. When waste gasification is applied, the produced syngas is generally combusted in a boiler to generate steam for energy recovery in a steam cycle. For both the possibilities--incineration or gasification--co-generation is the mean to improve energy recovery, especially for small scale plants. In the case of only electricity production, the achievable values are strongly dependent on the plant size: for large plant size, where advanced technical solutions can be applied and sustained from an economic point of view, net electric efficiency may reach values up to 30-31%. In small-medium plants, net electric efficiency is constrained by scale effect and remains at values around 20-24%. Other types of technical solutions--gasification with syngas use in internally fired devices, pyrolysis and plasma gasification--are less common or studied at pilot or demonstrative scale and, in any case, offer at present similar or lower levels of energy efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

The African disability scooter: efficiency testing in paediatric amputees in Malawi

PubMed Central

Beckles, Verona; McCahill, Jennifer L.; Stebbins, Julie; Mkandawire, Nyengo; Church, John C. T.; Lavy, Chris

2016-01-01

Abstract Purpose: The African Disability Scooter (ADS) was developed for lower limb amputees, to improve mobility and provide access to different terrains. The aim of this study was to test the efficiency of the ADS in Africa over different terrains. Method: Eight subjects with a mean age of 12 years participated. Energy expenditure and speed were calculated over different terrains using the ADS, a prosthetic limb, and crutches. Repeated testing was completed on different days to assess learning effect. Results: Speed was significantly faster with the ADS on a level surface compared to crutch walking. This difference was maintained when using the scooter on rough terrain. Oxygen cost was halved with the scooter on level ground compared to crutch walking. There were no significant differences in oxygen consumption or heart rate. There were significant differences in oxygen cost and speed between days using the scooter over level ground, suggesting the presence of a learning effect. Conclusions: This study demonstrates that the ADS is faster and more energy efficient than crutch walking in young individuals with amputations, and should be considered as an alternative to a prosthesis where this is not available. The presence of a learning effect suggests supervision and training is required when the scooter is first issued.Implications for RehabilitationThe African Disability Scooter:is faster than crutch walking in amputees;is more energy efficient than walking with crutches;supervised use is needed when learning to use the device;is a good alternative/adjunct for mobility. PMID:25316033

Strategies toward High Performance Organic Photovoltaic Cell: Material and Process

NASA Astrophysics Data System (ADS)

Kim, Bong Gi

The power conversion efficiency of organic photovoltaic (OPV) cells has been rapidly improved during the last few years and currently reaches around 10 %. The performance is evenly governed by absorption, exciton diffusion, exciton dissociation, carrier transfer, and collection efficiencies. Establishing a better understanding of OPV device physics combined with the development of new materials for each executive step contributes to this dramatic improvement. This dissertation focuses mainly on material design and development to correlate the intrinsic properties of organic semiconductors and the OPV performance. The introductory Chapter 1 briefly reviews the motivation of OPV research, its working mechanism, and representative organic materials for OPV application. Chapter 2 discusses the modulation of conjugated polymer's (CP's) absorption behavior and an efficient semi-empirical approach to predict CP's energy levels from its constituent monomers' HOMO/LUMO values. A strong acceptor lowered both the HOMO and LUMO levels of the CP, but the LUMO dropped more rapidly which ultimately produced a narrowed band-gap in the electron donating/accepting alternating copolymer system. In addition, the energy level difference between the CP and the constituent monomers converged to a constant value, providing an energy level prediction tool. Chapter 3 illustrates the systematic investigation on the relationship between the molecular structure of an energy harvesting organic dye and the exciton dissociation efficiency. The study showed that the quantum yield decreased as the exciton binding energy increases, and dipole moment direction should be properly oriented in the dye framework in order to improve photo-current generation when used in a dye sensitized photovoltaic device. Chapter 4 demonstrates the ultrasonic-assisted self-assembly of CPs in solution, rapidly and efficiently. Ultrasonication combined with dipolar media accelerated CP's aggregation, and the effect of CP's aggregation on the enhancement of OPV performance by promoting photo-current generation and increasing carrier mobility was systematically investigated. The correlation between the chemical structure of a CP and it aggregation behavior is further described in Chapter 5. To promote CP aggregate, a planar chain conformation was advantageous and CP aggregation improved hole mobility in the OPV device. However, thermally induced CP aggregates caused strong charge recombination, resulting in open circuit voltage drop. In Chapter 6, a novel polymer design principle to enable directed CP alignment is discussed. Regulating chain planarity and preventing massive crystallization of CP achieved by the developed molecular design principle allowed directed CP alignment under small shear flow.

Efficient generation of ultra-intense few-cycle radially polarized laser pulses.

PubMed

Carbajo, Sergio; Granados, Eduardo; Schimpf, Damian; Sell, Alexander; Hong, Kyung-Han; Moses, Jeffrey; Kärtner, Franz X

2014-04-15

We report on efficient generation of millijoule-level, kilohertz-repetition-rate few-cycle laser pulses with radial polarization by combining a gas-filled hollow-waveguide compression technique with a suitable polarization mode converter. Peak power levels >85  GW are routinely achieved, capable of reaching relativistic intensities >10(19)  W/cm2 with carrier-envelope-phase control, by employing readily accessible ultrafast high-energy laser technology.

Best Practices Manual, 2002 Edition.

ERIC Educational Resources Information Center

Collaborative for High Performance Schools, CA.

The goal of this manual is to create a new generation of high performance school facilities in California. The focus is on public schools and levels K-12, althoughmany of the design principals apply to private schools and higher education facilities as well. High performance schools are healthy, comfortable, energy efficient, resource efficient,…

Machine Learning of Accurate Energy-Conserving Molecular Force Fields

NASA Astrophysics Data System (ADS)

Chmiela, Stefan; Tkatchenko, Alexandre; Sauceda, Huziel; Poltavsky, Igor; Schütt, Kristof; Müller, Klaus-Robert; GDML Collaboration

Efficient and accurate access to the Born-Oppenheimer potential energy surface (PES) is essential for long time scale molecular dynamics (MD) simulations. Using conservation of energy - a fundamental property of closed classical and quantum mechanical systems - we develop an efficient gradient-domain machine learning (GDML) approach to construct accurate molecular force fields using a restricted number of samples from ab initio MD trajectories (AIMD). The GDML implementation is able to reproduce global potential-energy surfaces of intermediate-size molecules with an accuracy of 0.3 kcal/mol for energies and 1 kcal/mol/Å for atomic forces using only 1000 conformational geometries for training. We demonstrate this accuracy for AIMD trajectories of molecules, including benzene, toluene, naphthalene, malonaldehyde, ethanol, uracil, and aspirin. The challenge of constructing conservative force fields is accomplished in our work by learning in a Hilbert space of vector-valued functions that obey the law of energy conservation. The GDML approach enables quantitative MD simulations for molecules at a fraction of cost of explicit AIMD calculations, thereby allowing the construction of efficient force fields with the accuracy and transferability of high-level ab initio methods.

Citizens Utilities Company's successful residential new construction market transformation program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caulfield, T.O.; Shepherd, M.A.

1998-07-01

Citizens Utilities Company, Arizona Electric Division (CUC/AED) fielded a Residential New Construction Program (RNC) in the forth quarter of 1994 that had been designed from conception as a market transformation program. The CUC RNC Program encouraged builders to adopt energy efficient building practices for new homes by supplying builders estimates of energy savings, supplying inspections services to assist builders in applying energy efficient building practices while verifying compliance, and posting and promoting the home as energy efficient during the sales period. Measures generally required to qualify for the program were R-38 ceiling insulation, R-21 wall insulation, polysealing of all infiltrationmore » gaps during construction, well sealed air-conditioning ducts, and an air conditioner Seasonal Energy Efficiency Rating (SEER) of 11.0 or greater. In less than two years the program achieved over 17% market penetration without offering rebates to builders. This paper reviews the design of the program, including a discussion of the features felt to be primarily responsible for its success. It reviews the levels of penetration achieved, free-ridership, spillover, and market barriers encountered. Finally it proposes improvements to the program designed to carry it the next step toward a self-sustaining market transformation program.« less

Energy efficiency façade design in high-rise apartment buildings using the calculation of solar heat transfer through windows with shading devices

NASA Astrophysics Data System (ADS)

Ha, P. T. H.

2018-04-01

The architectural design orientation at the first design stage plays a key role and has a great impact on the energy consumption of a building throughout its life-cycle. To provide designers with a simple and useful tool in quantitatively determining and simply optimizing the energy efficiency of a building at the very first stage of conceptual design, a factor namely building envelope energy efficiency (Khqnl ) should be investigated and proposed. Heat transfer through windows and other glazed areas of mezzanine floors accounts for 86% of overall thermal transfer through building envelope, so the factor Khqnl of high-rise buildings largely depends on shading solutions. The author has established tables and charts to make reference to the values of Khqnl factor in certain high-rise apartment buildings in Hanoi calculated with a software program subject to various inputs including: types and sizes of shading devices, building orientations and at different points of time to be respectively analyzed. It is possible and easier for architects to refer to these tables and charts in façade design for a higher level of energy efficiency.

JPRS Report, Science and Technology, Europe.

DTIC Science & Technology

1989-06-16

nature of their central energy sources, to the complex distribution of gases around the nucleus and possibly to understanding the origin of the diffuse...development. CCD’s are ideal for single photon X-ray imaging and spectroscopy. They have a high quantum efficiency over a broad energy range, high spatial...resolution, low readout noise, and an energy resolution approaching 100 at high energy levels. Reflection gratings have been chosen for XMM rather

25. anniversary of the 1973 oil embargo: Energy trends since the first major U.S. energy crisis

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The purpose of this publication is not to assess the causes of the 1973 energy crisis or the measures that were adopted to resolve it. The intent is to present some data on which such analyses can be based. Many of the trends presented here fall into two distinct periods. From 1973 to the mid-1980`s, prices continued at very high levels, in part because of a second oil shock in 1979--80. During this period, rapid progress was made in raising American oil production, reducing dependence on oil imports, and improving end-use efficiency. After the oil price collapse of the mid-1980`s,more » however, prices retreated to more moderate levels, the pace of efficiency gains slowed, American oil production fell, and the share of imports rose. 30 figs.« less

The effects of an energy efficiency retrofit on indoor air quality.

PubMed

Frey, S E; Destaillats, H; Cohn, S; Ahrentzen, S; Fraser, M P

2015-04-01

To investigate the impacts of an energy efficiency retrofit, indoor air quality and resident health were evaluated at a low-income senior housing apartment complex in Phoenix, Arizona, before and after a green energy building renovation. Indoor and outdoor air quality sampling was carried out simultaneously with a questionnaire to characterize personal habits and general health of residents. Measured indoor formaldehyde levels before the building retrofit routinely exceeded reference exposure limits, but in the long-term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long-term follow-up sampling within certain resident subpopulations (i.e. residents who report smoking and residents who had lived longer at the apartment complex). © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Efficient modulation of optical and electrical properties of X-shaped thermally activated delayed fluorescence emitters by substitution.

PubMed

Fan, Jianzhong; Wang, Xin; Lin, Lili; Wang, Chuankui

2016-08-01

A series of X-shaped thermally activated delayed fluorescence (TADF) emitters are systematically studied by first-principles calculations. Effects of the cyano group adding to the acceptor unit and the hydroxyl group adding to the donor part on the optical and electrical properties are analyzed. It is found that both kinds of groups can efficiently increase the emission wavelength to realize full-color emission. Although they play different roles in modulating the energy level of frontier orbitals, the S-T energy gap, the reorganization energy and transfer integral for different molecules, they can efficiently increase the charge transfer rate and reduce the difference of electron transfer rate and hole transfer rate. These results indicate that these designed strategies are efficient to achieve balanced charge transfer rates and modulate emission colors. By analyzing the energy matching between the TADF emitters and three kinds of hosts, the emission spectra of the 3,5-bis(N-carbazolyl)benzene (mcp) and the absorption spectra of most TADF emitters have a large overlap, which provides helpful information in application of these TADF molecules.

Connectivity-enhanced route selection and adaptive control for the Chevrolet Volt

DOE PAGES

Gonder, Jeffrey; Wood, Eric; Rajagopalan, Sai

2016-01-01

The National Renewable Energy Laboratory and General Motors evaluated connectivity-enabled efficiency enhancements for the Chevrolet Volt. A high-level model was developed to predict vehicle fuel and electricity consumption based on driving characteristics and vehicle state inputs. These techniques were leveraged to optimize energy efficiency via green routing and intelligent control mode scheduling, which were evaluated using prospective driving routes between tens of thousands of real-world origin/destination pairs. The overall energy savings potential of green routing and intelligent mode scheduling was estimated at 5% and 3%, respectively. Furthermore, these represent substantial opportunities considering that they only require software adjustments to implement.

Implementation study of wearable sensors for activity recognition systems

PubMed Central

Ghassemian, Mona

2015-01-01

This Letter investigates and reports on a number of activity recognition methods for a wearable sensor system. The authors apply three methods for data transmission, namely ‘stream-based’, ‘feature-based’ and ‘threshold-based’ scenarios to study the accuracy against energy efficiency of transmission and processing power that affects the mote's battery lifetime. They also report on the impact of variation of sampling frequency and data transmission rate on energy consumption of motes for each method. This study leads us to propose a cross-layer optimisation of an activity recognition system for provisioning acceptable levels of accuracy and energy efficiency. PMID:26609413

The potential of Fourier transform infrared spectroscopy of milk samples to predict energy intake and efficiency in dairy cows.

PubMed

McParland, S; Berry, D P

2016-05-01

Knowledge of animal-level and herd-level energy intake, energy balance, and feed efficiency affect day-to-day herd management strategies; information on these traits at an individual animal level is also useful in animal breeding programs. A paucity of data (especially at the individual cow level), of feed intake in particular, hinders the inclusion of such attributes in herd management decision-support tools and breeding programs. Dairy producers have access to an individual cow milk sample at least once daily during lactation, and consequently any low-cost phenotyping strategy should consider exploiting measureable properties in this biological sample, reflecting the physiological status and performance of the cow. Infrared spectroscopy is the study of the interaction of an electromagnetic wave with matter and it is used globally to predict milk quality parameters on routinely acquired individual cow milk samples and bulk tank samples. Thus, exploiting infrared spectroscopy in next-generation phenotyping will ensure potentially rapid application globally with a negligible additional implementation cost as the infrastructure already exists. Fourier-transform infrared spectroscopy (FTIRS) analysis is already used to predict milk fat and protein concentrations, the ratio of which has been proposed as an indicator of energy balance. Milk FTIRS is also able to predict the concentration of various fatty acids in milk, the composition of which is known to change when body tissue is mobilized; that is, when the cow is in negative energy balance. Energy balance is mathematically very similar to residual energy intake (REI), a suggested measure of feed efficiency. Therefore, the prediction of energy intake, energy balance, and feed efficiency (i.e., REI) from milk FTIRS seems logical. In fact, the accuracy of predicting (i.e., correlation between predicted and actual values; root mean square error in parentheses) energy intake, energy balance, and REI from milk FTIRS in dairy cows was 0.88 (20.0MJ), 0.78 (18.6MJ), and 0.63 (22.0MJ), respectively, based on cross-validation. These studies, however, are limited to results from one research group based on data from 2 contrasting production systems in the United Kingdom and Ireland and would need to be replicated, especially in a range of production systems because the prediction equations are not accurate when the variability used in validation is not represented in the calibration data set. Heritable genetic variation exists for all predicted traits. Phenotypic differences in energy intake also exists among animals stratified based on genetic merit for energy intake predicted from milk FTIRS, substantiating the usefulness of such FTIR-predicted phenotypes not only for day-to-day herd management, but also as part of a breeding strategy to improve cow performance. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Size Effects in Dye-Sensitized TiO2 Clusters

NASA Astrophysics Data System (ADS)

Marom, Noa; Körzdörfer, Thomas; Ren, Xinguo; Tkatchenko, Alexandre; Chelikowsky, James

2014-03-01

The development of solar cells is driven by the need for clean and sustainable energy. Organic and dye sensitized cells are considered as promising technologies, particularly for large area, low cost applications. However, the efficiency of such cells is still far from the theoretical limit. Ab initio simulations may be used for computer-aided design of new materials and nano-structures for more efficient solar cells. It is essential to obtain an accurate description of the electronic structure, including the fundamental gaps and energy level alignment at the interfaces in the device active region. This requires going beyond ground-state DFT to the GW approximation. A recently developed GW method [PRB 86, 041110R (2012)] is applied to dye-sensitized TiO2 clusters [PRB 84, 245115 (2011)]. The effect of cluster size on the energy level alignment at the dye-TiO2 interface is discussed. With the increase in the TiO2 cluster size its gap narrows. The gap of the molecule attached to the cluster subsequently narrows due to screening. As a result, the energy level alignment at the interface changes in an unexpected way [Marom, Körzdörfer, Ren, Tkatchenko, Chelikowsky, to be published].

Energy efficiency in the U.S. residential sector: An engineering and economic assessment of opportunities for large energy savings and greenhouse gas emissions reductions

NASA Astrophysics Data System (ADS)

Lima de Azevedo, Ines Margarida

Energy efficiency and conservation is a very promising part of a portfolio of the needed strategies to mitigate climate change. Several technologies and energy efficiency measures in the residential sector offer potential for large energy savings. However, while energy efficiency options are currently considered as a means of reducing carbon emissions, there is still large uncertainty about the effect of such measures on overall carbon savings. The first part of this thesis provides a national assessment of the energy efficiency potential in the residential sector under several different scenarios, which include the perspectives of different economic agents (consumers, utilities, ESCOs, and a society). The scenarios also include maximizing energy, electricity or carbon dioxide savings. The second part of this thesis deals with a detailed assessment of the potential for white-light LEDs for energy and carbon dioxide savings in the U.S. commercial and residential sectors. Solid-state lighting shows great promise as a source of efficient, affordable, color-balanced white light. Indeed, assuming market discount rates, the present work demonstrates that white solid-state lighting already has a lower levelized annual cost (LAC) than incandescent bulbs and that it will be lower than that of the most efficient fluorescent bulbs by the end of this decade. However, a large literature indicates that households do not make their decisions in terms of simple expected economic value. The present analysis shows that incorporating the findings from literature on high implicit discount rates from households when performing decisions towards efficient technologies delays the adoption of white LEDs by a couple of years. After a review of the technology, the present work compares the electricity consumption, carbon emissions and cost-effectiveness of current lighting technologies, when accounting for expected performance evolution through 2015. Simulations of lighting electricity consumption and implicit greenhouse gases emissions for the U.S. residential and commercial sectors through 2015 under different policy scenarios (voluntary solid-state lighting adoption, implementation of lighting standards in new construction and rebate programs or equivalent subsidies) are also included.

High-efficiency generation of pulsed Lyman-α radiation by resonant laser wave mixing in low pressure Kr-Ar mixture.

PubMed

Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Louchev, Oleg A; Iwasaki, Masahiko; Wada, Satoshi

2016-04-04

We report an experimental generation of ns pulsed 121.568 nm Lyman-α radiation by the resonant nonlinear four-wave mixing of 212.556 nm and 845.015 nm radiation pulses providing a high conversion efficiency 1.7x10^-3 with the output pulse energy 3.6 μJ achieved using a low pressure Kr-Ar mixture. Theoretical analysis shows that this efficiency is achieved due to the advantage of using (i) the high input laser intensities in combination with (ii) the low gas pressure allowing us to avoid the onset of full-scale discharge in the laser focus. In particular, under our experimental conditions the main mechanism of photoionization caused by the resonant 2-photon 212.556 nm radiation excitation of Kr atoms followed by the 1-photon ionization leads to ≈17% loss of Kr atoms and efficiency loss only by the end of the pulse. The energy of free electrons, generated by 212.556 nm radiation via (2 + 1)-photon ionization and accelerated mainly by 845.015 nm radiation, remains during the pulse below the level sufficient for the onset of full-scale discharge by the electron avalanche. Our analysis also suggests that ≈30-fold increase of 845.015 nm pulse energy can allow one to scale up the L-α radiation pulse energy towards the level of ≈100 μJ.

A new strategy for efficient solar energy conversion: Parallel-processing with surface plasmons

NASA Technical Reports Server (NTRS)

Anderson, L. M.

1982-01-01

This paper introduces an advanced concept for direct conversion of sunlight to electricity, which aims at high efficiency by tailoring the conversion process to separate energy bands within the broad solar spectrum. The objective is to obtain a high level of spectrum-splitting without sequential losses or unique materials for each frequency band. In this concept, sunlight excites a spectrum of surface plasma waves which are processed in parallel on the same metal film. The surface plasmons transport energy to an array of metal-barrier-semiconductor diodes, where energy is extracted by inelastic tunneling. Diodes are tuned to different frequency bands by selecting the operating voltage and geometry, but all diodes share the same materials.

Elevating the triplet energy levels of dibenzofuran-based ambipolar phosphine oxide hosts for ultralow-voltage-driven efficient blue electrophosphorescence: from D-A to D-π-A systems.

PubMed

Han, Chunmiao; Zhang, Zhensong; Xu, Hui; Li, Jing; Zhao, Yi; Yan, Pengfei; Liu, Shiyong

2013-01-21

A series of donor (D)-π-acceptor (A)-type phosphine-oxide hosts (DBF(x) POPhCz(n)), which were composed of phenylcarbazole, dibenzofuran (DBF), and diphenylphosphine-oxide (DPPO) moieties, were designed and synthesized. Phenyl π-spacer groups were inserted between the carbazolyl and DBF groups, which effectively weakened the charge transfer and triplet-excited-state extension. As the result, the first triplet energy levels (T(1)) of DBF(x)POPhCz(n) are elevated to about 3.0 eV, 0.1 eV higher than their D-A-type analogues. Nevertheless, the electrochemical analysis and DFT calculations demonstrated the ambipolar characteristics of DBF(x)POPhCz(n). The phenyl π spacers hardly influenced the frontier molecular orbital (FMO) energy levels and the carrier-transporting ability of the materials. Therefore, these D-π-A systems are endowed with higher T(1) states, as well as comparable electrical properties to D-A systems. Phosphorescent blue-light-emitting diodes (PHOLEDs) that were based on DBF(x)POPhCz(n) not only inherited the ultralow driving voltages (2.4 V for onset, about 2.8 V at 200 cd m(-2), and <3.4 V at 1000 cd m(-2)) but also had much-improved efficiencies, including about 26 cd A(-1) for current efficiency, 30 Lm W(-1) for power efficiency, and 13% for external quantum efficiency, which were more than twice the values of devices that are based on conventional unipolar host materials. This performance makes DBFDPOPhCz(n) among the best hosts for ultralow-voltage-driven blue PHOLEDs reported so far. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energetics and biomechanics of locomotion by red kangaroos (Macropus rufus).

PubMed

Kram, R; Dawson, T J

1998-05-01

As red kangaroos hop faster over level ground, their rate of oxygen consumption (indicating metabolic energy consumption) remains nearly the same. This phenomenon has been attributed to exceptional elastic energy storage and recovery via long compliant tendons in the legs. Alternatively, red kangaroos may have exceptionally efficient muscles. To estimate efficiency, we measured the metabolic cost of uphill hopping, where muscle fibers must perform mechanical work against gravity. We found that uphill hopping was much more expensive than level hopping. The maximal rate of oxygen consumption measured (3 ml O2 kg-1 s-1) exceeds all but a few vertebrate species. However, efficiency values were normal, approximately 30%. At faster level hopping speeds the effective mechanical advantage of the extensor muscles of the ankle joint remained the same. Thus, kangaroos generate the same muscular force at all speeds but do so more rapidly at faster hopping speeds. This contradicts a recent hypothesis for what sets the cost of locomotion. The cost of transport (J kg-1 m-1) decreases at faster hopping speeds, yet red kangaroos prefer to use relatively slow speeds that avoid high levels of tendon stress.

Analytical Study on Multi-Tier 5G Heterogeneous Small Cell Networks: Coverage Performance and Energy Efficiency.

PubMed

Xiao, Zhu; Liu, Hongjing; Havyarimana, Vincent; Li, Tong; Wang, Dong

2016-11-04

In this paper, we investigate the coverage performance and energy efficiency of multi-tier heterogeneous cellular networks (HetNets) which are composed of macrocells and different types of small cells, i.e., picocells and femtocells. By virtue of stochastic geometry tools, we model the multi-tier HetNets based on a Poisson point process (PPP) and analyze the Signal to Interference Ratio (SIR) via studying the cumulative interference from pico-tier and femto-tier. We then derive the analytical expressions of coverage probabilities in order to evaluate coverage performance in different tiers and investigate how it varies with the small cells' deployment density. By taking the fairness and user experience into consideration, we propose a disjoint channel allocation scheme and derive the system channel throughput for various tiers. Further, we formulate the energy efficiency optimization problem for multi-tier HetNets in terms of throughput performance and resource allocation fairness. To solve this problem, we devise a linear programming based approach to obtain the available area of the feasible solutions. System-level simulations demonstrate that the small cells' deployment density has a significant effect on the coverage performance and energy efficiency. Simulation results also reveal that there exits an optimal small cell base station (SBS) density ratio between pico-tier and femto-tier which can be applied to maximize the energy efficiency and at the same time enhance the system performance. Our findings provide guidance for the design of multi-tier HetNets for improving the coverage performance as well as the energy efficiency.

Analytical Study on Multi-Tier 5G Heterogeneous Small Cell Networks: Coverage Performance and Energy Efficiency

PubMed Central

Xiao, Zhu; Liu, Hongjing; Havyarimana, Vincent; Li, Tong; Wang, Dong

2016-01-01

In this paper, we investigate the coverage performance and energy efficiency of multi-tier heterogeneous cellular networks (HetNets) which are composed of macrocells and different types of small cells, i.e., picocells and femtocells. By virtue of stochastic geometry tools, we model the multi-tier HetNets based on a Poisson point process (PPP) and analyze the Signal to Interference Ratio (SIR) via studying the cumulative interference from pico-tier and femto-tier. We then derive the analytical expressions of coverage probabilities in order to evaluate coverage performance in different tiers and investigate how it varies with the small cells’ deployment density. By taking the fairness and user experience into consideration, we propose a disjoint channel allocation scheme and derive the system channel throughput for various tiers. Further, we formulate the energy efficiency optimization problem for multi-tier HetNets in terms of throughput performance and resource allocation fairness. To solve this problem, we devise a linear programming based approach to obtain the available area of the feasible solutions. System-level simulations demonstrate that the small cells’ deployment density has a significant effect on the coverage performance and energy efficiency. Simulation results also reveal that there exits an optimal small cell base station (SBS) density ratio between pico-tier and femto-tier which can be applied to maximize the energy efficiency and at the same time enhance the system performance. Our findings provide guidance for the design of multi-tier HetNets for improving the coverage performance as well as the energy efficiency. PMID:27827917

Cost-Benefit of Improving the Efficiency of Room Air Conditioners (Inverter and Fixed Speed) in India

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, Nihar; Abhyankar, Nikit; Park, Won Young

Improving efficiency of air conditioners (ACs) typically involves improving the efficiency of various components such as compressors, heat exchangers, expansion valves, refrigerant and fans. We estimate the incremental cost of improving the efficiency of room ACs based on the cost of improving the efficiency of its key components. Further, we estimate the retail price increase required to cover the cost of efficiency improvement, compare it with electricity bill savings, and calculate the payback period for consumers to recover the additional price of a more efficient AC. We assess several efficiency levels, two of which are summarized below in the report.more » The finding that significant efficiency improvement is cost effective from a consumer perspective is robust over a wide range of assumptions. If we assume a 50% higher incremental price compared to our baseline estimate, the payback period for the efficiency level of 3.5 ISEER is 1.1 years. Given the findings of this study, establishing more stringent minimum efficiency performance criteria (one star level) should be evaluated rigorously considering significant benefits to consumers, energy security and environment.« less

Energy efficiency as a unifying principle for human, environmental, and global health

PubMed Central

Fontana, Luigi; Atella, Vincenzo; Kammen, Daniel M

2013-01-01

A strong analogy exists between over/under consumption of energy at the level of the human body and of the industrial metabolism of humanity. Both forms of energy consumption have profound implications for human, environmental, and global health. Globally, excessive fossil-fuel consumption, and individually, excessive food energy consumption are both responsible for a series of interrelated detrimental effects, including global warming, extreme weather conditions, damage to ecosystems, loss of biodiversity, widespread pollution, obesity, cancer, chronic respiratory disease, and other lethal chronic diseases. In contrast, data show that the efficient use of energy—in the form of food as well as fossil fuels and other resources—is vital for promoting human, environmental, and planetary health and sustainable economic development. While it is not new to highlight how efficient use of energy and food can address some of the key problems our world is facing, little research and no unifying framework exists to harmonize these concepts of sustainable system management across diverse scientific fields into a single theoretical body. Insights beyond reductionist views of efficiency are needed to encourage integrated changes in the use of the world’s natural resources, with the aim of achieving a wiser use of energy, better farming systems, and healthier dietary habits. This perspective highlights a range of scientific-based opportunities for cost-effective pro-growth and pro-health policies while using less energy and natural resources. PMID:24555053

Energy efficiency of growing ram lambs fed concentrate-based diets with different roughage sources.

PubMed

Galvani, D B; Pires, A V; Susin, I; Gouvêa, V N; Berndt, A; Chagas, L J; Dórea, J R R; Abdalla, A L; Tedeschi, L O

2014-01-01

Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P < 0.01). Lambs fed the diet with LQR had greater body fat (g/kg of empty BW) and energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P < 0.05). Using a low-quality roughage as a primary source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with LQR resulted in a 17% better efficiency of ME use for gain (P < 0.01), which was associated with a greater partial efficiency of energy retention as fat (P < 0.01). This increased nutritional efficiency, however, should be viewed with caution because it is related to visceral fat deposition, a nonedible tissue.

Probabilistic assessment of the potential indoor air impacts of vent-free gas heating appliances in energy-efficient homes in the United States.

PubMed

Whitmyre, Gary K; Pandian, Muhilan D

2018-06-01

Use of vent-free gas heating appliances for supplemental heating in U.S. homes is increasing. However, there is currently a lack of information on the potential impact of these appliances on indoor air quality for homes constructed according to energy-efficient and green building standards. A probabilistic analysis was conducted to estimate the impact of vent-free gas heating appliances on indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO 2 ), carbon dioxide (CO 2 ), water vapor, and oxygen in "tight" energy-efficient homes in the United States. A total of 20,000 simulations were conducted for each Department of Energy (DOE) heating region to capture a wide range of home sizes, appliance features, and conditions, by varying a number of parameters, e.g., room volume, house volume, outdoor humidity, air exchange rates, appliance input rates (Btu/hr), and house heat loss factors. Predicted airborne levels of CO were below the U.S. Environmental Protection Agency (EPA) standard of 9 ppm for all modeled cases. The airborne concentrations of NO 2 were below the U.S. Consumer Product Safety Commission (CPSC) guideline of 0.3 ppm and the Health Canada benchmark of 0.25 ppm in all cases and were below the World Health Organization (WHO) standard of 0.11 ppm in 99-100% of all cases. Predicted levels of CO 2 were below the Health Canada standard of 3500 ppm for all simulated cases. Oxygen levels in the room of vent-free heating appliance use were not significantly reduced. The great majority of cases in all DOE regions were associated with relative humidity (RH) levels from all indoor water vapor sources that were less than the EPA-recommended 70% RH maximum to avoid active mold and mildew growth. The conclusion of this investigation is that when installed in accordance with the manufacturer's instructions, vent-free gas heating appliances maintain acceptable indoor air quality in tight energy-efficient homes, as defined by the standards referenced in this report. Probabilistic modeling of indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO 2 ), carbon dioxide (CO 2 ), water vapor, and oxygen associated with use of vent-free gas heating appliances provides new data indicating that uses of these devices are consistent with acceptable indoor air quality in "tight" energy-efficient homes in the United States. This study will provide authoritative bodies such as the International Code Council with definitive information that will assist in the development of future versions of national building codes, and will provide evaluation of the performance of unvented gas heating products in energy conservation homes.

Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling.

PubMed

Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

2015-09-18

This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols.

Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling

PubMed Central

Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

2015-01-01

This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols. PMID:26393608

Quantifying the Financial Benefits of Multifamily Retrofits

DOE Office of Scientific and Technical Information (OSTI.GOV)

D. Philbrick; Scheu, R.; Brand, L.

The U.S. Department of Energy’s Building America research team Partnership for Advanced Residential Retrofit analyzed building, energy, and financial program data as well as other public and private data to examine the relationship between energy-efficiency retrofits and financial performance on three levels: building, city, and community.

Improved System Yields $100,000 Annual Savings (Systems Analysis at Alcoa Yields Significant Savings)

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1999-01-01

In another Office of Industrial Technologies Motor Challenge Success Story, Alcoa (formerly Alumax) aluminum reduced annual energy consumption by 12% and reduced both maintenance and noise levels. Order this fact sheet now to learn how your company can both increase energy efficiency and decrease pollution.

7 CFR 1780.57 - Design policies.

Code of Federal Regulations, 2014 CFR

2014-01-01

... et seq.). (c) Energy/environment. Facility design should consider cost effective energy-efficient and... distribution system water losses do not exceed reasonable levels. (g) Conformity with State drinking water... title XIV of the Public Health Service Act (commonly known as the ‘Safe Drinking Water Act’) (42 U.S.C...

7 CFR 1780.57 - Design policies.

Code of Federal Regulations, 2010 CFR

2010-01-01

... et seq.). (c) Energy/environment. Facility design should consider cost effective energy-efficient and... distribution system water losses do not exceed reasonable levels. (g) Conformity with State drinking water... title XIV of the Public Health Service Act (commonly known as the ‘Safe Drinking Water Act’) (42 U.S.C...

7 CFR 1780.57 - Design policies.

Code of Federal Regulations, 2011 CFR

2011-01-01

... et seq.). (c) Energy/environment. Facility design should consider cost effective energy-efficient and... distribution system water losses do not exceed reasonable levels. (g) Conformity with State drinking water... title XIV of the Public Health Service Act (commonly known as the ‘Safe Drinking Water Act’) (42 U.S.C...

7 CFR 1780.57 - Design policies.

Code of Federal Regulations, 2013 CFR

2013-01-01

... et seq.). (c) Energy/environment. Facility design should consider cost effective energy-efficient and... distribution system water losses do not exceed reasonable levels. (g) Conformity with State drinking water... title XIV of the Public Health Service Act (commonly known as the ‘Safe Drinking Water Act’) (42 U.S.C...

7 CFR 1780.57 - Design policies.

Code of Federal Regulations, 2012 CFR

2012-01-01

... et seq.). (c) Energy/environment. Facility design should consider cost effective energy-efficient and... distribution system water losses do not exceed reasonable levels. (g) Conformity with State drinking water... title XIV of the Public Health Service Act (commonly known as the ‘Safe Drinking Water Act’) (42 U.S.C...

Computer simulation of magnetic resonance spectra employing homotopy.

PubMed

Gates, K E; Griffin, M; Hanson, G R; Burrage, K

1998-11-01

Multidimensional homotopy provides an efficient method for accurately tracing energy levels and hence transitions in the presence of energy level anticrossings and looping transitions. Herein we describe the application and implementation of homotopy to the analysis of continuous wave electron paramagnetic resonance spectra. The method can also be applied to electron nuclear double resonance, electron spin echo envelope modulation, solid-state nuclear magnetic resonance, and nuclear quadrupole resonance spectra. Copyright 1998 Academic Press.

Evaluation of Ho:KPb2Cl5 as a Diode-Pumpable Mid-IR Laser Material

DTIC Science & Technology

2016-09-01

is the decay of the upper laser level without emitting light , due to the simultaneous emission of enough lattice vibrational quanta (phonons) to...have an energy level spacing that can result in emission at the desired laser wavelength, and that state must emit light efficiently. It is also...extremely desirable that it absorb light in the wavelength region where laser diodes operate most efficiently, approximately 800–1000 nm. This enables

In situ evaluation of water and energy consumptions at the end use level: The influence of flow reducers and temperature in baths.

PubMed

Matos, C; Briga-Sá, A; Bentes, I; Faria, D; Pereira, S

2017-05-15

Nowadays, water and energy consumption is intensifying every year in most of the countries. This perpetual increase will not be supportable in the long run, making urgently to manage these resources on a sustainable way. Domestic consumptions of water and electric energy usually are related and it's important to study that relation, identifying opportunities for use efficient improvement. In fact, without an understanding of water-energy relations, there are water efficiency measures that may lead to unintentional costs in the energy efficiency field. In order to take full advantage of combined effect between water and energy water management methodologies, it is necessary to collect data to ensure that the efforts are directed through the most effective paths. This paper presents a study based in the characterization, measurement and analysis of water and electricity consumption in a single family house (2months period) in order to find an interdependent relationship between consumptions at the end user level. The study was carried out on about 200 baths, divided in four different scenarios where the influence of two variables was tested: the flow reducer valve and the bath temperature. Data showed that the presence of flow reducer valve decreased electric energy consumption and water consumption, but increased the bath duration. Setting a lower temperature in water-heater, decreased electric consumption, water consumption and bath duration. Analysing the influence of the flow reducer valve and 60°C temperature simultaneously, it was concluded that it had a significant influence on electric energy consumption and on the baths duration but had no influence on water consumption. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Fatigue level estimation of monetary bills based on frequency band acoustic signals with feature selection by supervised SOM

NASA Astrophysics Data System (ADS)

Teranishi, Masaru; Omatu, Sigeru; Kosaka, Toshihisa

Fatigued monetary bills adversely affect the daily operation of automated teller machines (ATMs). In order to make the classification of fatigued bills more efficient, the development of an automatic fatigued monetary bill classification method is desirable. We propose a new method by which to estimate the fatigue level of monetary bills from the feature-selected frequency band acoustic energy pattern of banking machines. By using a supervised self-organizing map (SOM), we effectively estimate the fatigue level using only the feature-selected frequency band acoustic energy pattern. Furthermore, the feature-selected frequency band acoustic energy pattern improves the estimation accuracy of the fatigue level of monetary bills by adding frequency domain information to the acoustic energy pattern. The experimental results with real monetary bill samples reveal the effectiveness of the proposed method.

Assessment of Energy Efficiency Improvement and CO2 Emission Reduction Potentials in India's Cement Industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrow, III, William R.; Hasanbeigi, Ali; Xu, Tengfang

2012-12-03

India’s cement industry is the second largest in the world behind China with annual cement production of 168 Mt in 2010 which accounted for slightly greater than six percent of the world’s annual cement production in the same year. To produce that amount of cement, the industry consumed roughly 700 PJ of fuel and 14.7 TWh of electricity. We identified and analyzed 22 energy efficiency technologies and measures applicable to the processes in the Indian cement industry. The Conservation Supply Curve (CSC) used in this study is an analytical tool that captures both the engineering and the economic perspectives ofmore » energy conservation. Using a bottom-up electricity CSC model and compared to an electricity price forecast the cumulative cost-effective plant-level electricity savings potential for the Indian cement industry for 2010- 2030 is estimated to be 83 TWh, and the cumulative plant-level technical electricity saving potential is 89 TWh during the same period. The grid-level CO2 emissions reduction associated with cost-effective electricity savings is 82 Mt CO2 and the electric grid-level CO2 emission reduction associated with technical electricity saving potential is 88 Mt CO2. Compared to a fuel price forecast, an estimated cumulative cost-effective fuel savings potential of 1,029 PJ with associated CO2 emission reduction of 97 Mt CO2 during 2010-2030 is possible. In addition, a sensitivity analysis with respect to the discount rate used is conducted to assess the effect of changes in this parameter on the results. The result of this study gives a comprehensive and easy to understand perspective to the Indian cement industry and policy makers about the energy efficiency potential and its associated cost over the next twenty years.« less

Investigating the Gap Between Estimated and Actual Energy Efficiency and Conservation Savings for Public Buildings Projects & Programs in United States

NASA Astrophysics Data System (ADS)

Qaddus, Muhammad Kamil

The gap between estimated and actual savings in energy efficiency and conservation (EE&C) projects or programs forms the problem statement for the scope of public and government buildings. This gap has been analyzed first on impact and then on process-level. On the impact-level, the methodology leads to categorization of the gap as 'Realization Gap'. It then views the categorization of gap within the context of past and current narratives linked to realization gap. On process-level, the methodology leads to further analysis of realization gap on process evaluation basis. The process evaluation criterion, a product of this basis is then applied to two different programs (DESEU and NYC ACE) linked to the scope of this thesis. Utilizing the synergies of impact and process level analysis, it offers proposals on program development and its structure using our process evaluation criterion. Innovative financing and benefits distribution structure is thus developed and will remain part of the proposal. Restricted Stakeholder Crowd Financing and Risk-Free Incentivized return are the products of proposed financing and benefit distribution structure respectively. These products are then complimented by proposing an alternative approach in estimating EE&C savings. The approach advocates estimation based on range-allocation rather than currently utilized unique estimated savings approach. The Way Ahead section thus explores synergy between financial and engineering ranges of energy savings as a multi-discipline approach for future research. Moreover, it provides the proposed program structure with risk aversion and incentive allocation while dealing with uncertainty. This set of new approaches are believed to better fill the realization gap between estimated and actual energy efficiency savings.

Energy-Efficient Optimal Power Allocation in Integrated Wireless Sensor and Cognitive Satellite Terrestrial Networks

PubMed Central

Li, Guangxia; An, Kang; Gao, Bin; Zheng, Gan

2017-01-01

This paper proposes novel satellite-based wireless sensor networks (WSNs), which integrate the WSN with the cognitive satellite terrestrial network. Having the ability to provide seamless network access and alleviate the spectrum scarcity, cognitive satellite terrestrial networks are considered as a promising candidate for future wireless networks with emerging requirements of ubiquitous broadband applications and increasing demand for spectral resources. With the emerging environmental and energy cost concerns in communication systems, explicit concerns on energy efficient resource allocation in satellite networks have also recently received considerable attention. In this regard, this paper proposes energy-efficient optimal power allocation schemes in the cognitive satellite terrestrial networks for non-real-time and real-time applications, respectively, which maximize the energy efficiency (EE) of the cognitive satellite user while guaranteeing the interference at the primary terrestrial user below an acceptable level. Specifically, average interference power (AIP) constraint is employed to protect the communication quality of the primary terrestrial user while average transmit power (ATP) or peak transmit power (PTP) constraint is adopted to regulate the transmit power of the satellite user. Since the energy-efficient power allocation optimization problem belongs to the nonlinear concave fractional programming problem, we solve it by combining Dinkelbach’s method with Lagrange duality method. Simulation results demonstrate that the fading severity of the terrestrial interference link is favorable to the satellite user who can achieve EE gain under the ATP constraint comparing to the PTP constraint. PMID:28869546

Integrating theory, synthesis, spectroscopy and device efficiency to design and characterize donor materials for organic photovoltaics: a case study including 12 donors

DOE PAGES

Oosterhout, S. D.; Kopidakis, N.; Owczarczyk, Z. R.; ...

2015-04-07

There have been remarkable improvements in the power conversion efficiency of solution-processable Organic Photovoltaics (OPV) have largely been driven by the development of novel narrow bandgap copolymer donors comprising an electron-donating (D) and an electron-withdrawing (A) group within the repeat unit. The large pool of potential D and A units and the laborious processes of chemical synthesis and device optimization, has made progress on new high efficiency materials slow with a few new efficient copolymers reported every year despite the large number of groups pursuing these materials. In our paper we present an integrated approach toward new narrow bandgap copolymersmore » that uses theory to guide the selection of materials to be synthesized based on their predicted energy levels, and time-resolved microwave conductivity (TRMC) to select the best-performing copolymer–fullerene bulk heterojunction to be incorporated into complete OPV devices. We validate our methodology by using a diverse group of 12 copolymers, including new and literature materials, to demonstrate good correlation between (a) theoretically determined energy levels of polymers and experimentally determined ionization energies and electron affinities and (b) photoconductance, measured by TRMC, and OPV device performance. The materials used here also allow us to explore whether further copolymer design rules need to be incorporated into our methodology for materials selection. For example, we explore the effect of the enthalpy change (ΔH) during exciton dissociation on the efficiency of free charge carrier generation and device efficiency and find that ΔH of -0.4 eV is sufficient for efficient charge generation.« less

Maximizing Energy Savings Reliability in BC Hydro Industrial Demand-side Management Programs: An Assessment of Performance Incentive Models

NASA Astrophysics Data System (ADS)

Gosman, Nathaniel

For energy utilities faced with expanded jurisdictional energy efficiency requirements and pursuing demand-side management (DSM) incentive programs in the large industrial sector, performance incentive programs can be an effective means to maximize the reliability of planned energy savings. Performance incentive programs balance the objectives of high participation rates with persistent energy savings by: (1) providing financial incentives and resources to minimize constraints to investment in energy efficiency, and (2) requiring that incentive payments be dependent on measured energy savings over time. As BC Hydro increases its DSM initiatives to meet the Clean Energy Act objective to reduce at least 66 per cent of new electricity demand with DSM by 2020, the utility is faced with a higher level of DSM risk, or uncertainties that impact the costeffective acquisition of planned energy savings. For industrial DSM incentive programs, DSM risk can be broken down into project development and project performance risks. Development risk represents the project ramp-up phase and is the risk that planned energy savings do not materialize due to low customer response to program incentives. Performance risk represents the operational phase and is the risk that planned energy savings do not persist over the effective measure life. DSM project development and performance risks are, in turn, a result of industrial economic, technological and organizational conditions, or DSM risk factors. In the BC large industrial sector, and characteristic of large industrial sectors in general, these DSM risk factors include: (1) capital constraints to investment in energy efficiency, (2) commodity price volatility, (3) limited internal staffing resources to deploy towards energy efficiency, (4) variable load, process-based energy saving potential, and (5) a lack of organizational awareness of an operation's energy efficiency over time (energy performance). This research assessed the capacity of alternative performance incentive program models to manage DSM risk in BC. Three performance incentive program models were assessed and compared to BC Hydro's current large industrial DSM incentive program, Power Smart Partners -- Transmission Project Incentives, itself a performance incentive-based program. Together, the selected program models represent a continuum of program design and implementation in terms of the schedule and level of incentives provided, the duration and rigour of measurement and verification (M&V), energy efficiency measures targeted and involvement of the private sector. A multi criteria assessment framework was developed to rank the capacity of each program model to manage BC large industrial DSM risk factors. DSM risk management rankings were then compared to program costeffectiveness, targeted energy savings potential in BC and survey results from BC industrial firms on the program models. The findings indicate that the reliability of DSM energy savings in the BC large industrial sector can be maximized through performance incentive program models that: (1) offer incentives jointly for capital and low-cost operations and maintenance (O&M) measures, (2) allow flexible lead times for project development, (3) utilize rigorous M&V methods capable of measuring variable load, process-based energy savings, (4) use moderate contract lengths that align with effective measure life, and (5) integrate energy management software tools capable of providing energy performance feedback to customers to maximize the persistence of energy savings. While this study focuses exclusively on the BC large industrial sector, the findings of this research have applicability to all energy utilities serving large, energy intensive industrial sectors.

A model study of assisted adiabatic transfer of population in the presence of collisional dephasing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masuda, Shumpei, E-mail: shumpei.masuda@aalto.fi; Rice, Stuart A., E-mail: s-rice@uchicago.edu

2015-06-28

Previous studies have demonstrated that when experimental conditions generate non-adiabatic dynamics that prevents highly efficient population transfer between states of an isolated system by stimulated Raman adiabatic passage (STIRAP), the addition of an auxiliary counter-diabatic field (CDF) can restore most or all of that efficiency. This paper examines whether that strategy is also successful in a non-isolated system in which the energies of the states fluctuate, e.g., when a solute is subject to collisions with solvent. We study population transfer in two model systems: (i) the three-state system used by Demirplak and Rice [J. Chem. Phys. 116, 8028 (2002)] andmore » (ii) a four-state system, derived from the simulation studies of Demirplak and Rice [J. Chem. Phys. 125, 194517 (2006)], that mimics HCl in liquid Ar. Simulation studies of the vibrational manifold of HCl in dense fluid Ar show that the collision induced vibrational energy level fluctuations have asymmetric distributions. Representations of these asymmetric energy level fluctuation distributions are used in both models (i) and (ii). We identify three sources of degradation of the efficiency of STIRAP generated selective population transfer in model (ii): too small pulse areas of the laser fields, unwanted interference arising from use of strong fields, and the vibrational detuning. For both models (i) and (ii), our examination of the efficiency of STIRAP + CDF population transfer under the influence of the asymmetric distribution of the vibrational energy fluctuations shows that there is a range of field strengths and pulse durations under which STIRAP + CDF control of population transfer has greater efficiency than does STIRAP generated population transfer.« less

Analysis of Energy Consumption for Ad Hoc Wireless Sensor Networks Using a Bit-Meter-per-Joule Metric

NASA Astrophysics Data System (ADS)

Gao, J. L.

2002-04-01

In this article, we present a system-level characterization of the energy consumption for sensor network application scenarios. We compute a power efficiency metric -- average watt-per-meter -- for each radio transmission and extend this local metric to find the global energy consumption. This analysis shows how overall energy consumption varies with transceiver characteristics, node density, data traffic distribution, and base-station location.

Effect of occupant behavior and air-conditioner controls on humidity in typical and high-efficiency homes

DOE PAGES

Winkler, Jon; Munk, Jeffrey; Woods, Jason

2018-04-01

Increasing insulation levels and improved windows are reducing sensible cooling loads in high-efficiency homes. This trend raises concerns that the resulting shift in the balance of sensible and latent cooling loads may result in higher indoor humidity, occupant discomfort, and stunted adoption of high-efficiency homes. This study utilizes established moisture-buffering and air-conditioner latent degradation models in conjunction with an approach to stochastically model internal gains. Building loads and indoor humidity levels are compared for simulations of typical new construction homes and high-efficiency homes in 10 US cities. The sensitivity of indoor humidity to changes in cooling set point, air-conditioner capacity,more » and blower control parameters are evaluated. The results show that high-efficiency homes in humid climates have cooling loads with a higher fraction of latent loads than the typical new construction home, resulting in higher indoor humidity. Reducing the cooling set point is the easiest method to reduce indoor humidity, but it is not energy efficient, and overcooling may lead to occupant discomfort. Eliminating the blower operation at the end of cooling cycles and reducing the cooling airflow rate also reduce indoor humidity and with a smaller impact on energy use and comfort.« less

Effect of occupant behavior and air-conditioner controls on humidity in typical and high-efficiency homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winkler, Jon; Munk, Jeffrey; Woods, Jason

Increasing insulation levels and improved windows are reducing sensible cooling loads in high-efficiency homes. This trend raises concerns that the resulting shift in the balance of sensible and latent cooling loads may result in higher indoor humidity, occupant discomfort, and stunted adoption of high-efficiency homes. This study utilizes established moisture-buffering and air-conditioner latent degradation models in conjunction with an approach to stochastically model internal gains. Building loads and indoor humidity levels are compared for simulations of typical new construction homes and high-efficiency homes in 10 US cities. The sensitivity of indoor humidity to changes in cooling set point, air-conditioner capacity,more » and blower control parameters are evaluated. The results show that high-efficiency homes in humid climates have cooling loads with a higher fraction of latent loads than the typical new construction home, resulting in higher indoor humidity. Reducing the cooling set point is the easiest method to reduce indoor humidity, but it is not energy efficient, and overcooling may lead to occupant discomfort. Eliminating the blower operation at the end of cooling cycles and reducing the cooling airflow rate also reduce indoor humidity and with a smaller impact on energy use and comfort.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feibel, C.E.

This study uses multiple data collection and research methods including in depth interviews, 271 surveys of shared taxi and minibus operators, participant observation, secondary sources, and the literature on public transport from low, medium, and high-income countries. Extensive use is also made of a survey administered in Istanbul in 1976 to 1935 paratransit operators. Primary findings are that private buses are more efficient than public buses on a cost per passenger-km basis, and that private minibuses are as efficient as public buses. In terms of energy efficiency, minibuses are almost as efficient as public and private buses using actual-occupancy levels.more » Large shared taxis are twice as cost and energy efficient as cars, and small shared taxis 50% more efficient. In terms of investment cost per seat, large shared taxis have the lowest cost followed by smaller shared taxis, minibuses, and buses. Considering actual occupancy levels, minibuses are only slightly less effective in terms of congestion than buses, and large and small shared taxis are twice as effective as cars. It is also shown that minibuses and shared taxis have better service quality than buses because of higher frequencies and speeds, and because they provide a much higher probability of getting a seat than buses. Analysis of regulation and policy suggests that there are many unintended cost of public-transport regulations.« less

Random benzotrithiophene-based donor-acceptor copolymers for efficient organic photovoltaic devices.

PubMed

Nielsen, Christian B; Ashraf, Raja Shahid; Schroeder, Bob C; D'Angelo, Pasquale; Watkins, Scott E; Song, Kigook; Anthopoulos, Thomas D; McCulloch, Iain

2012-06-14

A series of benzotrithiophene-containing random terpolymers for polymer solar cells is reported. Through variations of the two other components in the terpolymers, the absorption profile and the frontier energy levels are optimized and maximum power conversion efficiencies are nearly doubled (5.14%) relative to the parent alternating copolymer.

Energy-Efficient Crowdsensing of Human Mobility and Signal Levels in Cellular Networks

PubMed Central

Foremski, Paweł; Gorawski, Michał; Grochla, Krzysztof; Polys, Konrad

2015-01-01

The paper presents a practical application of the crowdsensing idea to measure human mobility and signal coverage in cellular networks. Currently, virtually everyone is carrying a mobile phone, which may be used as a sensor to gather research data by measuring, e.g., human mobility and radio signal levels. However, many users are unwilling to participate in crowdsensing experiments. This work begins with the analysis of the barriers for engaging people in crowdsensing. A survey showed that people who agree to participate in crowdsensing expect a minimum impact on their battery lifetime and phone usage habits. To address these requirements, this paper proposes an application for measuring the location and signal strength data based on energy-efficient GPS tracking, which allows one to perform the measurements of human mobility and radio signal levels with minimum energy utilization and without any engagement of the user. The method described combines measurements from the accelerometer with effective management of the GPS to monitor the user mobility with the decrease in battery lifetime by approximately 20%. To show the applicability of the proposed platform, the sample results of signal level distribution and coverage maps gathered for an LTE network and representing human mobility are shown. PMID:26340633

Building America Case Study: Philadelphia Housing Authority Energy-Efficiency Turnover Protocols, Philadelphia, Pennsylvania

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-02-01

Over one million HUD-supported public housing units provide rental housing for eligible low-income families across the country. A survey of over 100 public housing authorities (PHAs) across the country indicated that there is a high level of interest in developing low-cost solutions that improve energy efficiency and can be seamlessly included in the refurbishment process. Further, PHAs, have incentives (both internal and external) to reduce utility bills. ARIES worked with four PHAs to develop packages of energy efficiency retrofit measures the PHAs can cost-effectively implement with their own staffs in the normal course of housing operations at the time whenmore » units are refurbished between occupancies. The energy efficiency turnover protocols emphasized air infiltration reduction, duct sealing, and measures that improve equipment efficiency. ARIES documented implementation in 18 housing units. Reductions in average air leakage were 16 percent and duct leakage reductions averaged 23 percent. Total source energy consumption savings due to implemented measures was estimated at 3-10 percent based on BEopt modeling with a simple payback of 1.6 to 2.5 years. Implementation challenges were encountered mainly related to required operational changes and budgetary constraints. Nevertheless, simple measures can feasibly be accomplished by PHA staff at low or no cost. At typical housing unit turnover rates, these measures could impact hundreds of thousands of units per year nationally.« less

Islip Housing Authority Energy Efficiency Turnover Protocols, Islip, New York (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2014-08-01

More than 1 million HUD-supported public housing units provide rental housing for eligible low-income families across the country. A survey of over 100 PHAs across the country indicated that there is a high level of interest in developing low cost solutions that improve energy efficiency and can be seamlessly included in the refurbishment process. Further, PHAs, have incentives (both internal and external) to reduce utility bills. ARIES worked with two public housing authorities (PHAs) to develop packages of energy efficiency retrofit measures the PHAs can cost effectively implement with their own staffs in the normal course of housing operations atmore » the time when units are refurbished between occupancies. The energy efficiency turnover protocols emphasized air infiltration reduction, duct sealing and measures that improve equipment efficiency. ARIES documented implementation in ten housing units. Reductions in average air leakage were 16-20% and duct leakage reductions averaged 38%. Total source energy consumption savings was estimated at 6-10% based on BEopt modeling with a simple payback of 1.7 to 2.2 years. Implementation challenges were encountered mainly related to required operational changes and budgetary constraints. Nevertheless, simple measures can feasibly be accomplished by PHA staff at low or no cost. At typical housing unit turnover rates, these measures could impact hundreds of thousands of unit per year nationally.« less

Convolutional networks for fast, energy-efficient neuromorphic computing

PubMed Central

Esser, Steven K.; Merolla, Paul A.; Arthur, John V.; Cassidy, Andrew S.; Appuswamy, Rathinakumar; Andreopoulos, Alexander; Berg, David J.; McKinstry, Jeffrey L.; Melano, Timothy; Barch, Davis R.; di Nolfo, Carmelo; Datta, Pallab; Amir, Arnon; Taba, Brian; Flickner, Myron D.; Modha, Dharmendra S.

2016-01-01

Deep networks are now able to achieve human-level performance on a broad spectrum of recognition tasks. Independently, neuromorphic computing has now demonstrated unprecedented energy-efficiency through a new chip architecture based on spiking neurons, low precision synapses, and a scalable communication network. Here, we demonstrate that neuromorphic computing, despite its novel architectural primitives, can implement deep convolution networks that (i) approach state-of-the-art classification accuracy across eight standard datasets encompassing vision and speech, (ii) perform inference while preserving the hardware’s underlying energy-efficiency and high throughput, running on the aforementioned datasets at between 1,200 and 2,600 frames/s and using between 25 and 275 mW (effectively >6,000 frames/s per Watt), and (iii) can be specified and trained using backpropagation with the same ease-of-use as contemporary deep learning. This approach allows the algorithmic power of deep learning to be merged with the efficiency of neuromorphic processors, bringing the promise of embedded, intelligent, brain-inspired computing one step closer. PMID:27651489

Convolutional networks for fast, energy-efficient neuromorphic computing.

PubMed

Esser, Steven K; Merolla, Paul A; Arthur, John V; Cassidy, Andrew S; Appuswamy, Rathinakumar; Andreopoulos, Alexander; Berg, David J; McKinstry, Jeffrey L; Melano, Timothy; Barch, Davis R; di Nolfo, Carmelo; Datta, Pallab; Amir, Arnon; Taba, Brian; Flickner, Myron D; Modha, Dharmendra S

2016-10-11

Deep networks are now able to achieve human-level performance on a broad spectrum of recognition tasks. Independently, neuromorphic computing has now demonstrated unprecedented energy-efficiency through a new chip architecture based on spiking neurons, low precision synapses, and a scalable communication network. Here, we demonstrate that neuromorphic computing, despite its novel architectural primitives, can implement deep convolution networks that (i) approach state-of-the-art classification accuracy across eight standard datasets encompassing vision and speech, (ii) perform inference while preserving the hardware's underlying energy-efficiency and high throughput, running on the aforementioned datasets at between 1,200 and 2,600 frames/s and using between 25 and 275 mW (effectively >6,000 frames/s per Watt), and (iii) can be specified and trained using backpropagation with the same ease-of-use as contemporary deep learning. This approach allows the algorithmic power of deep learning to be merged with the efficiency of neuromorphic processors, bringing the promise of embedded, intelligent, brain-inspired computing one step closer.

Waking the sleeping giant: Introducing new heat exchanger technology into the residential air-conditioning marketplace

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapp, T.; Voss, M.; Stephens, C.

1998-07-01

The Air Conditioning Industry has made tremendous strides in improvements to the energy efficiency and reliability of its product offerings over the past 40 years. These improvement can be attributed to enhancements of components, optimization of the energy cycle, and modernized and refined manufacturing techniques. During this same period, energy consumption for space cooling has grown significantly. In January of 1992, the minimum efficiency requirement for central air conditioning equipment was raised to 10 SEER. This efficiency level is likely to increase further under the auspices of the National Appliance Energy Conservation Act (NAECA). A new type of heat exchangermore » was developed for air conditioning equipment by Modine Manufacturing Company in the early 1990's. Despite significant advantages in terms of energy efficiency, dehumidification, durability, and refrigerant charge there has been little interest expressed by the air conditioning industry. A cooperative effort between Modine, various utilities, and several state energy offices has been organized to test and demonstrate the viability of this heat exchanger design throughout the nation. This paper will review the fundamentals of heat exchanger design and document this simple, yet novel technology. These experiences involving equipment retrofits have been documented with respect to the performance potential of air conditioning system constructed with PF{trademark} Heat Exchangers (generically referred to as microchannel heat exchangers) from both an energy efficiency as well as a comfort perspective. The paper will also detail the current plan to introduce 16 to 24 systems into an extended field test throughout the US which commenced in the Fall of 1997.« less

Microwave Driven Magnetic Plasma Accelerator Studies (CYCLOPS)

NASA Technical Reports Server (NTRS)

Crimi, G. F.; Eckert, A. C.; Miller, D. B.

1967-01-01

A microwave-driven cyclotron resonance plasma acceleration device was investigated using argon, krypton, xenon, and mercury as propellants. Limited ranges of propellant flow rate, input power, and magnetic field strength were used. Over-all efficiencies (including the 65% efficiency of the input polarizer) less than 10% were obtained for specific impulse values between 500 and 1500 sec. Power transfer efficiencies, however, approached 100% of the input power available in the right-hand component of the incident circularly polarized radiation. Beam diagnostics using Langmuir probes, cold gas mapping, r-f mapping and ion energy analyses were performed in conjunction with an engine operating in a pulsed mode. Measurements of transverse electron energies at the position of cyclotron resonant absorption yielded energy values more than an order of magnitude lower than anticipated. The measured electron energies were, however, consistent with the low values of average ion energy measured by retarding potential techniques. The low values of average ion energy were also consistent with the measured thrust values. It is hypothesized that ionization and radiation limit the electron kinetic energy to low-values thus limiting the energy which is finally transferred to the ion. Thermalization by electron-electron collision was also identified as an additional loss mechanism. The use of light alkali metals, which have relatively few low lying energy levels to excite, with the input power to mass ratio selected so as to limit the electron energies to less than the second ionization potential, is suggested. It is concluded, however, that the over-all efficiency for such propellants would be less than 40 per cent.

Enhancing monellin production by Pichia pastoris at low cell induction concentration via effectively regulating methanol metabolism patterns and energy utilization efficiency

PubMed Central

Jia, Luqiang; Tu, Tingyong; Huai, Qiangqiang; Sun, Jiaowen; Chen, Shanshan; Li, Xin; Ding, Jian

2017-01-01

In heterologous protein productions by P. pastoris, methanol induction is generally initiated when cell concentration reaches very high density. The alternative strategy by initiating methanol induction at lower cells concentration was also reported to be effective in easing DO control, reducing toxic by-metabolites accumulation and increasing targeted proteins titers. However, the methanol/energy regulation mechanisms are seldom reported. We theoretically analyzed the methanol/energy metabolisms in protein expression process with the strategies of initiating induction at higher or lower cells concentrations, using monellin production as a prototype. When initiating induction at lower cells concentration and controlling induction temperature at 30°C, monellin concentration reached the highest levels of 2.62~2.71 g/L, which was 2.5~4.9 fold of those obtained with the strategy of initiating induction at higher cells concentration. With the desired induction strategy, 1) carbon metabolism ratio directing into the precursors synthesis route for monellin production reached the highest level of 65%, carbon metabolism ratios towards to precursors synthesis and ATP regeneration routes were regulated at relatively balanced levels; 2) monellin synthesis was completely cell growth associated, with the largest associated coefficient and higher specific growth rate; 3) theoretical NADH (energy) utilization efficiency η was the highest, and η stayed high levels (≥0.8) during most period (89%) within induction phase to supply sufficient energy in supporting monellin synthesis. PMID:28981536

Enhancing monellin production by Pichia pastoris at low cell induction concentration via effectively regulating methanol metabolism patterns and energy utilization efficiency.

PubMed

Jia, Luqiang; Tu, Tingyong; Huai, Qiangqiang; Sun, Jiaowen; Chen, Shanshan; Li, Xin; Shi, Zhongping; Ding, Jian

2017-01-01

In heterologous protein productions by P. pastoris, methanol induction is generally initiated when cell concentration reaches very high density. The alternative strategy by initiating methanol induction at lower cells concentration was also reported to be effective in easing DO control, reducing toxic by-metabolites accumulation and increasing targeted proteins titers. However, the methanol/energy regulation mechanisms are seldom reported. We theoretically analyzed the methanol/energy metabolisms in protein expression process with the strategies of initiating induction at higher or lower cells concentrations, using monellin production as a prototype. When initiating induction at lower cells concentration and controlling induction temperature at 30°C, monellin concentration reached the highest levels of 2.62~2.71 g/L, which was 2.5~4.9 fold of those obtained with the strategy of initiating induction at higher cells concentration. With the desired induction strategy, 1) carbon metabolism ratio directing into the precursors synthesis route for monellin production reached the highest level of 65%, carbon metabolism ratios towards to precursors synthesis and ATP regeneration routes were regulated at relatively balanced levels; 2) monellin synthesis was completely cell growth associated, with the largest associated coefficient and higher specific growth rate; 3) theoretical NADH (energy) utilization efficiency η was the highest, and η stayed high levels (≥0.8) during most period (89%) within induction phase to supply sufficient energy in supporting monellin synthesis.

A socio-technical approach to improving retail energy efficiency behaviours.

PubMed

Christina, Sian; Waterson, Patrick; Dainty, Andrew; Daniels, Kevin

2015-03-01

In recent years, the UK retail sector has made a significant contribution to societal responses on carbon reduction. We provide a novel and timely examination of environmental sustainability from a systems perspective, exploring how energy-related technologies and strategies are incorporated into organisational life. We use a longitudinal case study approach, looking at behavioural energy efficiency from within one of the UK's leading retailers. Our data covers a two-year period, with qualitative data from a total of 131 participants gathered using phased interviews and focus groups. We introduce an adapted socio-technical framework approach in order to describe an existing organisational behavioural strategy to support retail energy efficiency. Our findings point to crucial socio-technical and goal-setting factors which both impede and/or enable energy efficient behaviours, these include: tensions linked to store level perception of energy management goals; an emphasis on the importance of technology for underpinning change processes; and, the need for feedback and incentives to support the completion of energy-related tasks. We also describe the evolution of a practical operational intervention designed to address issues raised in our findings. Our study provides fresh insights into how sustainable workplace behaviours can be achieved and sustained over time. Secondly, we discuss in detail a set of issues arising from goal conflict in the workplace; these include the development of a practical energy management strategy to facilitate secondary organisational goals through job redesign. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Flapping wing applied to wind generators

NASA Astrophysics Data System (ADS)

Colidiuc, Alexandra; Galetuse, Stelian; Suatean, Bogdan

2012-11-01

The new conditions at the international level for energy source distributions and the continuous increasing of energy consumption must lead to a new alternative resource with the condition of keeping the environment clean. This paper offers a new approach for a wind generator and is based on the theoretical aerodynamic model. This new model of wind generator helped me to test what influences would be if there will be a bird airfoil instead of a normal wind generator airfoil. The aim is to calculate the efficiency for the new model of wind generator. A representative direction for using the renewable energy is referred to the transformation of wind energy into electrical energy, with the help of wind turbines; the development of such systems lead to new solutions based on high efficiency, reduced costs and suitable to the implementation conditions.

Energy-level alignment and open-circuit voltage at graphene/polymer interfaces: theory and experiment

NASA Astrophysics Data System (ADS)

Noori, Keian; Konios, Dimitrios; Stylianakis, Minas M.; Kymakis, Emmanuel; Giustino, Feliciano

2016-03-01

Functionalized graphene promises to become a key component of novel solar cell architectures, owing to its versatile ability to act either as transparent conductor, electron acceptor, or buffer layer. In spite of this promise, the solar energy conversion efficiency of graphene-based devices falls short of the performance of competing solution-processable photovoltaic technologies. Here we address the question of the maximum achievable open-circuit voltage of all-organic graphene: polymer solar cells using a combined theoretical/experimental approach, going from the atomic scale level to the device level. Our calculations on very large atomistic models of the graphene/polymer interface indicate that the ideal open-circuit voltage approaches one volt, and that epoxide functional groups can have a dramatic effect on the photovoltage. Our predictions are confirmed by direct measurements on complete devices where we control the concentration of functional groups via chemical reduction. Our findings indicate that the selective removal of epoxide groups and the use of ultradisperse polymers are key to achieving graphene solar cells with improved energy conversion efficiency.

Mission Assessment of the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)

NASA Technical Reports Server (NTRS)

Dankanich, John W.; Polzin, Kurt A.

2008-01-01

Pulsed inductive thrusters have typically been considered for future, high-power, missions requiring nuclear electric propulsion. These high-power systems, while promising equivalent or improved performance over state-of-the-art propulsion systems, presently have no planned missions for which they are well suited. The ability to efficiently operate an inductive thruster at lower energy and power levels may provide inductive thrusters near term applicability and mission pull. The Faraday Accelerator with Radio-frequency Assisted Discharge concept demonstrated potential for a high-efficiency, low-energy pulsed inductive thruster. The added benefits of energy recapture and/or pulse compression are shown to enhance the performance of the pulsed inductive propulsion system, yielding a system that con compete with and potentially outperform current state-of-the-art electric propulsion technologies. These enhancements lead to mission-level benefits associated with the use of a pulsed inductive thruster. Analyses of low-power near to mid-term missions and higher power far-term missions are undertaken to compare the performance of pulsed inductive thrusters with that delivered by state-of-the-art and development-level electric propulsion systems.

Dynamic Geospatial Modeling of the Building Stock to Project Urban Energy Demand.

PubMed

Breunig, Hanna Marie; Huntington, Tyler; Jin, Ling; Robinson, Alastair; Scown, Corinne Donahue

2018-06-26

In the United States, buildings account for more than 40 percent of total energy consumption, and the evolution of the urban form will impact the effectiveness of strategies to reduce energy use and mitigate emissions. This paper presents a broadly applicable approach for modeling future commercial, residential, and industrial floorspace, thermal consumption (heating and cooling), and associated GHG emissions at the tax assessor land parcel level. The approach accounts for changing building standards and retrofitting, climate change, and trends in housing and industry. We demonstrate the automated workflow for California, and project building stock, thermal energy consumption, and associated GHG emissions out to 2050. Our results suggest that if buildings in California have long lifespans, and minimal energy efficiency improvements compared to building codes reflective of 2008, then the state will face a 20% or higher increase in thermal energy consumption by 2050. Baseline annual GHG emissions associated with thermal energy consumption in the modeled building stock in 2016 is 34% below 1990 levels (110 Mt CO2eq/y).While the 2020 targets for the reduction of GHG emissions set by the California Senate Bill 350 have already been met, none of our scenarios achieve >80% reduction from 1990 levels by 2050, despite assuming an 86% reduction in electricity carbon intensity in our "Low Carbon" scenario. The results highlight the challenge California faces in meeting its new energy efficiency targets unless the State's building stock undergoes timely and strategic turnover, paired with deep retrofitting of existing buildings and natural gas equipment.

The Advancement of Cool Roof Standards in China from 2010 to 2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ge, Jing; Levinson, Ronnen M.

Since the initiation of the U.S.-China Clean Energy Research Center-Building Energy Efficiency (CERC-BEE) cool roof research collaboration between the Lawrence Berkeley National Laboratory Heat Island Group and Chinese institutions in 2010, new cool surface credits (insulation trade- offs) have been adopted in Chinese building energy efficiency standards, industry standards, and green building standards. JGJ 75-2012: Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Warm Winter Zone became the first national level standard to provide cool surface credits. GB/T 50378-2014: Assessment Standard for Green Building is the first national level green building standard that offers points formore » heat island mitigation. JGJ/T 359-2015: Technical Specification for Application of Architectural Reflective Thermal Insulation Coating is the first industry standard that offers cool coating credits for both public and residential buildings in all hot-summer climates (Hot Summer/Cold Winter, Hot Summer/Warm Winter). As of December 2015, eight provinces or municipalities in hot-summer regions have credited cool surfaces credits in their residential and/or public building design standards; five other provinces or municipalities in hot-summer regions recommend, but do not credit, the use of cool surfaces in their building design standards. Cool surfaces could be further advanced in China by including cool roof credits for residential and public building energy efficiency standards in all hot-summer regions; developing a standardized process for natural exposure and aged-property rating of cool roofing products; and adapting the U.S.-developed laboratory aging process for roofing materials to replicate solar reflectance changes induced by natural exposure in China.« less

Efficiency of transfer of essential polyunsaturated fatty acids versus organic carbon from producers to consumers in a eutrophic reservoir.

PubMed

Gladyshev, Michail I; Sushchik, Nadezhda N; Anishchenko, Olesia V; Makhutova, Olesia N; Kolmakov, Vladimir I; Kalachova, Galina S; Kolmakova, Anzhelika A; Dubovskaya, Olga P

2011-02-01

One of the central paradigms of ecology is that only about 10% of organic carbon production of one trophic level is incorporated into new biomass of organisms of the next trophic level. Many of energy-yielding compounds of carbon are designated as 'essential', because they cannot be synthesized de novo by consumers and must be obtained with food, while they play important structural and regulatory functions. The question arises: are the essential compounds transferred through trophic chains with the same efficiency as bulk carbon? To answer this question, we measured gross primary production of phytoplankton and secondary production of zooplankton and content of organic carbon and essential polyunsaturated fatty acids of ω-3 family with 18-22 carbon atoms (PUFA) in the biomass of phytoplankton and zooplankton in a small eutrophic reservoir during two summers. Transfer efficiency between the two trophic levels, phytoplankton (producers) and zooplankton (consumers), was calculated as ratio of the primary production versus the secondary (zooplankton) production for both carbon and PUFA. We found that the essential PUFA were transferred from the producers to the primary consumers with about twice higher efficiency than bulk carbon. In contrast, polyunsaturated fatty acids with 16 carbon atoms, which are synthesized exclusively by phytoplankton, but are not essential for animals, had significantly lower transfer efficiency than both bulk carbon, and essential PUFA. Thus, the trophic pyramid concept, which implicitly implies that all the energy-yielding compounds of carbon are transferred from one trophic level to the next with the same efficiency of about on average 10%, should be specified for different carbon compounds.

Facility Energy Performance Benchmarking in a Data-Scarce Environment

DTIC Science & Technology

2017-08-01

environment, and analyze occupant-, system-, and component-level faults contributing to energy in- efficiency. A methodology for developing DoD-specific...Research, Development, Test, and Evaluation (RDTE) Program to develop an intelligent framework, encompassing methodology and model- ing, that...energy performers by installation, climate zone, and other criteria. A methodology for creating the DoD-specific EUIs would be an important part of a

Development of Design Guidance for K-12 Schools from 30% to 50% Energy Savings: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pless, S.; Torcellini, P.; Long, N.

2008-07-01

This paper describes the development of energy efficiency recommendations for achieving 30% whole-building energy savings in K-12 schools over levels achieved by following the ANSI/ASHRAE/IESNA Standard 90.1. These design recommendations look at building envelope, fenestration, lighting systems (including electrical lights and daylighting), HVAC systems, building automation and controls, outside air treatment, and service water heating.

Valuing uncertain cash flows from investments that enhance energy efficiency.

PubMed

Abadie, Luis M; Chamorro, José M; González-Eguino, Mikel

2013-02-15

There is a broad consensus that investments to enhance energy efficiency quickly pay for themselves in lower energy bills and spared emission allowances. However, investments that at first glance seem worthwhile usually are not undertaken. One of the plausible, non-excluding explanations is the numerous uncertainties that these investments face. This paper deals with the optimal time to invest in an energy efficiency enhancement at a facility already in place that consumes huge amounts of a fossil fuel (coal) and operates under carbon constraints. We follow the Real Options approach. Our model comprises three sources of uncertainty following different stochastic processes which allows for application in a broad range of settings. We assess the investment option by means of a three-dimensional binomial lattice. We compute the trigger investment cost, i.e., the threshold level below which immediate investment would be optimal. We analyze the major drivers of this decision thus aiming at the most promising policies in this regard. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chance-constrained economic dispatch with renewable energy and storage

DOE PAGES

Cheng, Jianqiang; Chen, Richard Li-Yang; Najm, Habib N.; ...

2018-04-19

Increased penetration of renewables, along with uncertainties associated with them, have transformed how power systems are operated. High levels of uncertainty means that it is not longer possible to guarantee operational feasibility with certainty, instead constraints are required to be satisfied with high probability. We present a chance-constrained economic dispatch model that efficiently integrates energy storage and high renewable penetration to satisfy renewable portfolio requirements. Specifically, it is required that wind energy contributes at least a prespecified ratio of the total demand and that the scheduled wind energy is dispatchable with high probability. We develop an approximated partial sample averagemore » approximation (PSAA) framework to enable efficient solution of large-scale chanceconstrained economic dispatch problems. Computational experiments on the IEEE-24 bus system show that the proposed PSAA approach is more accurate, closer to the prescribed tolerance, and about 100 times faster than sample average approximation. Improved efficiency of our PSAA approach enables solution of WECC-240 system in minutes.« less

Chance-constrained economic dispatch with renewable energy and storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Jianqiang; Chen, Richard Li-Yang; Najm, Habib N.

Increased penetration of renewables, along with uncertainties associated with them, have transformed how power systems are operated. High levels of uncertainty means that it is not longer possible to guarantee operational feasibility with certainty, instead constraints are required to be satisfied with high probability. We present a chance-constrained economic dispatch model that efficiently integrates energy storage and high renewable penetration to satisfy renewable portfolio requirements. Specifically, it is required that wind energy contributes at least a prespecified ratio of the total demand and that the scheduled wind energy is dispatchable with high probability. We develop an approximated partial sample averagemore » approximation (PSAA) framework to enable efficient solution of large-scale chanceconstrained economic dispatch problems. Computational experiments on the IEEE-24 bus system show that the proposed PSAA approach is more accurate, closer to the prescribed tolerance, and about 100 times faster than sample average approximation. Improved efficiency of our PSAA approach enables solution of WECC-240 system in minutes.« less

Potential Evaluation of Solar Heat Assisted Desiccant Hybrid Air Conditioning System

NASA Astrophysics Data System (ADS)

Tran, Thien Nha; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

The solar thermal driven desiccant dehumidification-absorption cooling hybrid system has superior advantage in hot-humid climate regions. The reasonable air processing of desiccant hybrid air conditioning system and the utility of clean and free energy make the system environment friendly and energy efficient. The study investigates the performance of the desiccant dehumidification air conditioning systems with solar thermal assistant. The investigation is performed for three cases which are combinations of solar thermal and absorption cooling systems with different heat supply temperature levels. Two solar thermal systems are used in the study: the flat plate collector (FPC) and the vacuum tube with compound parabolic concentrator (CPC). The single-effect and high energy efficient double-, triple-effect LiBr-water absorption cooling cycles are considered for cooling systems. COP of desiccant hybrid air conditioning systems are determined. The evaluation of these systems is subsequently performed. The single effect absorption cooling cycle combined with the flat plate collector solar system is found to be the most energy efficient air conditioning system.

Design of experiment analysis of CO2 dielectric barrier discharge conditions on CO production

NASA Astrophysics Data System (ADS)

Becker, Markus; Ponduri, Srinath; Engeln, Richard; van de Sanden, Richard; Loffhagen, Detlef

2016-09-01

Dielectric barrier discharges (DBD) are frequently used for the generation of CO from CO2 which is of particular interest for syngas production. It has been found by means of fluid modelling in that the CO2 conversion frequency in a CO2 DBD depends linearly on the specific energy input (SEI) while the energy efficiency of CO production is only weakly dependent on the SEI. Here, the same numerical model as in is applied to study systematically the influence of gas pressure, applied voltage amplitude and frequency on the CO2 conversion frequency and the energy efficiency of CO production based on a 2-level 3-factor full factorial experimental design. It is found that the operating conditions of the CO2 DBD for CO production can be chosen to either have an optimal throughput or a better energy efficiency. This work was partly supported by the German Research Foundation within the Collaborative Research Centre Transregio 24.

Mitochondrial oxidative phosphorylation efficiency is upregulated during fasting in two major oxidative tissues of ducklings.

PubMed

Monternier, Pierre-Axel; Teulier, Loïc; Drai, Jocelyne; Bourguignon, Aurore; Collin-Chavagnac, Delphine; Hervant, Frédéric; Rouanet, Jean-Louis; Roussel, Damien

2017-10-01

Fasted endothermic vertebrates must develop physiological responses to maximize energy conservation and survival. The aim of this study was to determine the effect of 1-wk. fasting in 5-wk. old ducklings (Cairina moschata) from whole-body resting metabolic rate and body temperature to metabolic phenotype of tissues and mitochondrial coupling efficiency. At the level of whole organism, the mass-specific metabolic rate of ducklings was decreased by 40% after 1-wk. of fasting, which was associated with nocturnal Tb declines and shallow diurnal hypothermia during fasting. At the cellular level, fasting induced a large reduction in liver, gastrocnemius (oxidative) and pectoralis (glycolytic) muscle masses together with a fuel selection towards lipid oxidation and ketone body production in liver and a lower glycolytic phenotype in skeletal muscles. At the level of mitochondria, fasting induced a reduction of oxidative phosphorylation activities and an up-regulation of coupling efficiency (+30% on average) in liver and skeletal muscles. The present integrative study shows that energy conservation in fasted ducklings is mainly achieved by an overall reduction in mitochondrial activity and an increase in mitochondrial coupling efficiency, which would, in association with shallow hypothermia, increase the conservation of endogenous fuel stores during fasting. Copyright © 2017 Elsevier Inc. All rights reserved.

10 CFR 433.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... stage when the energy efficiency and sustainability details (such as insulation levels, HVAC systems, water-using systems, etc.) are either explicitly determined or implicitly included in a project cost...

High energy efficiency and high power density proton exchange membrane fuel cells: Electrode kinetics and mass transport

NASA Technical Reports Server (NTRS)

Srinivasan, Supramaniam; Velev, Omourtag A.; Parthasathy, Arvind; Manko, David J.; Appleby, A. John

1991-01-01

The development of proton exchange membrane (PEM) fuel cell power plants with high energy efficiencies and high power densities is gaining momentum because of the vital need of such high levels of performance for extraterrestrial (space, underwater) and terrestrial (power source for electric vehicles) applications. Since 1987, considerable progress has been made in achieving energy efficiencies of about 60 percent at a current density of 200 mA/sq cm and high power densities (greater than 1 W/sq cm) in PEM fuel cells with high (4 mg/sq cm) or low (0.4 mg/sq cm) platinum loadings in electrodes. The following areas are discussed: (1) methods to obtain these high levels of performance with low Pt loading electrodes - by proton conductor impregnation into electrodes, localization of Pt near front surface; (2) a novel microelectrode technique which yields electrode kinetic parameters for oxygen reduction and mass transport parameters; (3) demonstration of lack of water transport from anode to cathode; (4) modeling analysis of PEM fuel cell for comparison with experimental results and predicting further improvements in performance; and (5) recommendations of needed research and development for achieving the above goals.

A review of technologies and performances of thermal treatment systems for energy recovery from waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lombardi, Lidia, E-mail: lidia.lombardi@unicusano.it; Carnevale, Ennio; Corti, Andrea

2015-03-15

Highlights: • The topic of energy recovery from waste by thermal treatment is reviewed. • Combustion, gasification and pyrolysis were considered. • Data about energy recovery performances were collected and compared. • Main limitations to high values of energy performances were illustrated. • Diffusion of energy recovery from waste in EU, USA and other countries was discussed. - Abstract: The aim of this work is to identify the current level of energy recovery through waste thermal treatment. The state of the art in energy recovery from waste was investigated, highlighting the differences for different types of thermal treatment, considering combustion/incineration,more » gasification and pyrolysis. Also different types of wastes – Municipal Solid Waste (MSW), Refuse Derived Fuel (RDF) or Solid Refuse Fuels (SRF) and some typologies of Industrial Waste (IW) (sludge, plastic scraps, etc.) – were included in the analysis. The investigation was carried out mainly reviewing papers, published in scientific journals and conferences, but also considering technical reports, to gather more information. In particular the goal of this review work was to synthesize studies in order to compare the values of energy conversion efficiencies measured or calculated for different types of thermal processes and different types of waste. It emerged that the dominant type of thermal treatment is incineration associated to energy recovery in a steam cycle. When waste gasification is applied, the produced syngas is generally combusted in a boiler to generate steam for energy recovery in a steam cycle. For both the possibilities – incineration or gasification – cogeneration is the mean to improve energy recovery, especially for small scale plants. In the case of only electricity production, the achievable values are strongly dependent on the plant size: for large plant size, where advanced technical solutions can be applied and sustained from an economic point of view, net electric efficiency may reach values up to 30–31%. In small-medium plants, net electric efficiency is constrained by scale effect and remains at values around 20–24%. Other types of technical solutions – gasification with syngas use in internally fired devices, pyrolysis and plasma gasification – are less common or studied at pilot or demonstrative scale and, in any case, offer at present similar or lower levels of energy efficiency.« less

Energy utilization in fluctuating biological energy converters

PubMed Central

Szőke, Abraham; Hajdu, Janos

2016-01-01

We have argued previously [Szoke et al., FEBS Lett. 553, 18–20 (2003); Curr. Chem. Biol. 1, 53–57 (2007)] that energy utilization and evolution are emergent properties based on a small number of established laws of physics and chemistry. The relevant laws constitute a framework for biology on a level intermediate between quantum chemistry and cell biology. There are legitimate questions whether these concepts are valid at the mesoscopic level. Such systems fluctuate appreciably, so it is not clear what their efficiency is. Advances in fluctuation theorems allow the description of such systems on a molecular level. We attempt to clarify this topic and bridge the biochemical and physical descriptions of mesoscopic systems. PMID:27191009

Comparison of holographic lens and filter systems for lateral spectrum splitting

NASA Astrophysics Data System (ADS)

Vorndran, Shelby; Chrysler, Benjamin; Kostuk, Raymond K.

2016-09-01

Spectrum splitting is an approach to increasing the conversion efficiency of a photovoltaic (PV) system. Several methods can be used to perform this function which requires efficient spatial separation of different spectral bands of the incident solar radiation. In this paper several of holographic methods for implementing spectrum splitting are reviewed along with the benefits and disadvantages associated with each approach. The review indicates that a volume holographic lens has many advantages for spectrum splitting in terms of both power conversion efficiency and energy yield. A specific design for a volume holographic spectrum splitting lens is discussed for use with high bandgap InGaP and low bandgap silicon PV cells. The holographic lenses are modeled using rigorous coupled wave analysis, and the optical efficiency is evaluated using non-sequential raytracing. A proof-of-concept off-axis holographic lens is also recorded in dichromated gelatin film and the spectral diffraction efficiency of the hologram is measured with multiple laser sources across the diffracted spectral band. The experimental volume holographic lens (VHL) characteristics are compared to an ideal spectrum splitting filter in terms of power conversion efficiency and energy yield in environments with high direct normal incidence (DNI) illumination and high levels of diffuse illumination. The results show that the experimental VHL can achieve 62.5% of the ideal filter power conversion efficiency, 64.8% of the ideal filter DNI environment energy yield, and 57.7% of the ideal diffuse environment energy yield performance.

7 CFR 1710.255 - Energy efficiency work plans-energy efficiency borrowers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 11 2014-01-01 2014-01-01 false Energy efficiency work plans-energy efficiency... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.255 Energy efficiency work plans—energy efficiency borrowers. (a) All energy efficiency borrowers must maintain a...

Engineering the Implementation of Pumped Hydro Energy Storage in the Arizona Power Grid

NASA Astrophysics Data System (ADS)

Dixon, William Jesse J.

This thesis addresses the issue of making an economic case for bulk energy storage in the Arizona bulk power system. Pumped hydro energy storage (PHES) is used in this study. Bulk energy storage has often been suggested for large scale electric power systems in order to levelize load (store energy when it is inexpensive [energy demand is low] and discharge energy when it is expensive [energy demand is high]). It also has the potential to provide opportunities to avoid transmission and generation expansion, and provide for generation reserve margins. As the level of renewable energy resources increases, the uncertainty and variability of wind and solar resources may be improved by bulk energy storage technologies. For this study, the MATLab software platform is used, a mathematical based modeling language, optimization solvers (specifically Gurobi), and a power flow solver (PowerWorld) are used to simulate an economic dispatch problem that includes energy storage and transmission losses. A program is created which utilizes quadratic programming to analyze various cases using a 2010 summer peak load from the Arizona portion of the Western Electricity Coordinating Council (WECC) system. Actual data from industry are used in this test bed. In this thesis, the full capabilities of Gurobi are not utilized (e.g., integer variables, binary variables). However, the formulation shown here does create a platform such that future, more sophisticated modeling may readily be incorporated. The developed software is used to assess the Arizona test bed with a low level of energy storage to study how the storage power limit effects several optimization outputs such as the system wide operating costs. Large levels of energy storage are then added to see how high level energy storage affects peak shaving, load factor, and other system applications. Finally, various constraint relaxations are made to analyze why the applications tested eventually approach a constant value. This research illustrates the use of energy storage which helps minimize the system wide generator operating cost by "shaving" energy off of the peak demand. The thesis builds on the work of another recent researcher with the objectives of strengthening the assumptions used, checking the solutions obtained, utilizing higher level simulation languages to affirm results, and expanding the results and conclusions. One important point not fully discussed in the present thesis is the impact of efficiency in the pumped hydro cycle. The efficiency of the cycle for modern units is estimated at higher than 90%. Inclusion of pumped hydro losses is relegated to future work.

Rapid charging of thermal energy storage materials through plasmonic heating.

PubMed

Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

2014-09-01

Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites.

Rapid Charging of Thermal Energy Storage Materials through Plasmonic Heating

PubMed Central

Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

2014-01-01

Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites. PMID:25175717

Performance Evaluation of Energy-Autonomous Sensors Using Power-Harvesting Beacons for Environmental Monitoring in Internet of Things (IoT).

PubMed

Moiş, George Dan; Sanislav, Teodora; Folea, Silviu Corneliu; Zeadally, Sherali

2018-05-25

Environmental conditions and air quality monitoring have become crucial today due to the undeniable changes of the climate and accelerated urbanization. To efficiently monitor environmental parameters such as temperature, humidity, and the levels of pollutants, such as fine particulate matter (PM2.5) and volatile organic compounds (VOCs) in the air, and to collect data covering vast geographical areas, the development of cheap energy-autonomous sensors for large scale deployment and fine-grained data acquisition is required. Rapid advances in electronics and communication technologies along with the emergence of paradigms such as Cyber-Physical Systems (CPSs) and the Internet of Things (IoT) have led to the development of low-cost sensor devices that can operate unattended for long periods of time and communicate using wired or wireless connections through the Internet. We investigate the energy efficiency of an environmental monitoring system based on Bluetooth Low Energy (BLE) beacons that operate in the IoT environment. The beacons developed measure the temperature, the relative humidity, the light intensity, and the CO₂ and VOC levels in the air. Based on our analysis we have developed efficient sleep scheduling algorithms that allow the sensor nodes developed to operate autonomously without requiring the replacement of the power supply. The experimental results show that low-power sensors communicating using BLE technology can operate autonomously (from the energy perspective) in applications that monitor the environment or the air quality in indoor or outdoor settings.

Public Housing: A Tailored Approach to Energy Retrofits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dentz, J.; Conlin, F.; Podorson, D.

2014-06-01

Over one million HUD-supported public housing units provide rental housing for eligible low-income families across the country. A survey of over 100 PHAs across the country indicated that there is a high level of interest in developing low cost solutions that improve energy efficiency and can be seamlessly included in the refurbishment process. Further, PHAs, have incentives (both internal and external) to reduce utility bills. ARIES worked with two public housing authorities (PHAs) to develop packages of energy efficiency retrofit measures the PHAs can cost effectively implement with their own staffs in the normal course of housing operations at themore » time when units are refurbished between occupancies. The energy efficiency turnover protocols emphasized air infiltration reduction, duct sealing and measures that improve equipment efficiency. ARIES documented implementation in ten housing units. Reductions in average air leakage were 16-20% and duct leakage reductions averaged 38%. Total source energy consumption savings was estimated at 6-10% based on BEopt modeling with a simple payback of 1.7 to 2.2 years. Implementation challenges were encountered mainly related to required operational changes and budgetary constraints. Nevertheless, simple measures can feasibly be accomplished by PHA staff at low or no cost. At typical housing unit turnover rates, these measures could impact hundreds of thousands of unit per year nationally.« less

Enhanced performances for top-emitting white organic light-emitting diodes by utilizing green phosphor as energy transfer medium

NASA Astrophysics Data System (ADS)

Deng, Lingling; Bao, Yiyang; Zhang, Yanan; Peng, Ling; Zhu, Wenjing; Zhao, Yue; Xu, Yewen; Chen, Shufen

2016-06-01

In top-emitting white organic light-emitting diodes (TWOLEDs), the device performances attribute to the several important factors, such as exciton profile, energy transfer, and microcavity effect. In this paper, a TWOLED containing a heterojunction blue emission layer (EML) and a red EML is reported. A host material with high triplet energy level is employed for the adjacent blue and red EML, while the inefficient red emission reduces the emission efficiency of the TWOLED. In order to enhance the red emission efficiency, mixed-host and co-doping technologies are used in the red EML. By mixing the hole transporting and electron transporting host materials, the exciton recombination zone extends to the red EML to increase the red emission intensity and reduce the efficiency roll-off. And by co-doping a green phosphor into the red EML as the energy transfer medium, the energy transfer rate is enhanced, and then the current efficiency increases. Besides, both the mixed-host and co-doping change the carrier transport and the exciton recombination zone, which further affects the microcavity resonance in the devices. Due to the enhancement on the red emission intensity and the shift of resonant wavelength, the chromaticity of the TWOLED is improved.

Ecological conversion efficiency and its influencers in twelve species of fish in the Yellow Sea Ecosystem

NASA Astrophysics Data System (ADS)

Tang, Qisheng; Guo, Xuewu; Sun, Yao; Zhang, Bo

2007-09-01

The ecological conversion efficiencies in twelve species of fish in the Yellow Sea Ecosystem, i.e., anchovy ( Engraulis japonicus), rednose anchovy ( Thrissa kammalensis), chub mackerel ( Scomber japonicus), halfbeak ( Hyporhamphus sajori), gizzard shad ( Konosirus punctatus), sand lance ( Ammodytes personatus), red seabream ( Pagrus major), black porgy ( Acanthopagrus schlegeli), black rockfish ( Sebastes schlegeli), finespot goby ( Chaeturichthys stigmatias), tiger puffer ( Takifugu rubripes), and fat greenling ( Hexagrammos otakii), were estimated through experiments conducted either in situ or in a laboratory. The ecological conversion efficiencies were significantly different among these species. As indicated, the food conversion efficiencies and the energy conversion efficiencies varied from 12.9% to 42.1% and from 12.7% to 43.0%, respectively. Water temperature and ration level are the main factors influencing the ecological conversion efficiencies of marine fish. The higher conversion efficiency of a given species in a natural ecosystem is acquired only under the moderate environment conditions. A negative relationship between ecological conversion efficiency and trophic level among ten species was observed. Such a relationship indicates that the ecological efficiency in the upper trophic levels would increase after fishing down marine food web in the Yellow Sea ecosystem.

High Energy Density Regenerative Fuel Cell Systems for Terrestrial Applications

NASA Technical Reports Server (NTRS)

Burke, Kenneth A.

1999-01-01

Regenerative Fuel Cell System (RFCS) technology for energy storage has been a NASA power system concept for many years. Compared to battery-based energy storage systems, RFCS has received relatively little attention or resources for development because the energy density and electrical efficiency were not sufficiently attractive relative to advanced battery systems. Even today, RFCS remains at a very low technology readiness level (TRL of about 2 indicating feasibility has been demonstrated). Commercial development of the Proton Exchange Membrane (PEM) fuel cells for automobiles and other terrestrial applications and improvements in lightweight pressure vessel design to reduce weight and improve performance make possible a high energy density RFCS energy storage system. The results from this study of a lightweight RFCS energy storage system for a remotely piloted, solar-powered, high altitude aircraft indicate an energy density up to 790 w-h/kg with electrical efficiency of 53.4% is attainable. Such an energy storage system would allow a solar-powered aircraft to carry hundreds of kilograms of payload and remain in flight indefinitely for use in atmospheric research, earth observation, resource mapping. and telecommunications. Future developments in the areas of hydrogen and oxygen storage, pressure vessel design, higher temperature and higher- pressure fuel cell operation, unitized regenerative fuel cells, and commercial development of fuel cell technology will improve both the energy density and electrical efficiency of the RFCS.

Ireland's Generic Repeat Design Schools Programme

ERIC Educational Resources Information Center

Sheppard, Tony

2011-01-01

The Irish Department of Education and Skills (DoE) is strongly committed to energy efficiency and to reducing CO[subscript 2] by developing and implementing energy level ceilings in relation to school design that aim to remain below half of the accepted good practice in the field. This approach works within normal departmental budgetary limits to…

Effect of diet energy level and genomic residual feed intake on dairy heifer performance

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the growth, feed intake, and feed efficiency of dairy heifers with different genomically predicted residual feed intakes (RFI), and offered diets differing in energy density. Post-bred Holstein heifers (N=128; ages 14-20 months) were blocked by initial we...

Electric train energy consumption modeling

DOE PAGES

Wang, Jinghui; Rakha, Hesham A.

2017-05-01

For this paper we develop an electric train energy consumption modeling framework considering instantaneous regenerative braking efficiency in support of a rail simulation system. The model is calibrated with data from Portland, Oregon using an unconstrained non-linear optimization procedure, and validated using data from Chicago, Illinois by comparing model predictions against the National Transit Database (NTD) estimates. The results demonstrate that regenerative braking efficiency varies as an exponential function of the deceleration level, rather than an average constant as assumed in previous studies. The model predictions are demonstrated to be consistent with the NTD estimates, producing a predicted error ofmore » 1.87% and -2.31%. The paper demonstrates that energy recovery reduces the overall power consumption by 20% for the tested Chicago route. Furthermore, the paper demonstrates that the proposed modeling approach is able to capture energy consumption differences associated with train, route and operational parameters, and thus is applicable for project-level analysis. The model can be easily implemented in traffic simulation software, used in smartphone applications and eco-transit programs given its fast execution time and easy integration in complex frameworks.« less

Electric train energy consumption modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jinghui; Rakha, Hesham A.

For this paper we develop an electric train energy consumption modeling framework considering instantaneous regenerative braking efficiency in support of a rail simulation system. The model is calibrated with data from Portland, Oregon using an unconstrained non-linear optimization procedure, and validated using data from Chicago, Illinois by comparing model predictions against the National Transit Database (NTD) estimates. The results demonstrate that regenerative braking efficiency varies as an exponential function of the deceleration level, rather than an average constant as assumed in previous studies. The model predictions are demonstrated to be consistent with the NTD estimates, producing a predicted error ofmore » 1.87% and -2.31%. The paper demonstrates that energy recovery reduces the overall power consumption by 20% for the tested Chicago route. Furthermore, the paper demonstrates that the proposed modeling approach is able to capture energy consumption differences associated with train, route and operational parameters, and thus is applicable for project-level analysis. The model can be easily implemented in traffic simulation software, used in smartphone applications and eco-transit programs given its fast execution time and easy integration in complex frameworks.« less

Absence of Intramolecular Singlet Fission in Pentacene-Perylenediimide Heterodimers: The Role of Charge Transfer State.

PubMed

Wang, Long; Wu, Yishi; Chen, Jianwei; Wang, Lanfen; Liu, Yanping; Yu, Zhenyi; Yao, Jiannian; Fu, Hongbing

2017-11-16

A new class of donor-acceptor heterodimers based on two singlet fission (SF)-active chromophores, i.e., pentacene (Pc) and perylenediimide (PDI), was developed to investigate the role of charge transfer (CT) state on the excitonic dynamics. The CT state is efficiently generated upon photoexcitation. However, the resulting CT state decays to different energy states depending on the energy levels of the CT state. It undergoes extremely rapid deactivation to the ground state in polar CH 2 Cl 2 , whereas it undergoes transformation to a Pc triplet in nonpolar toluene. The efficient triplet generation in toluene is not due to SF but CT-mediated intersystem crossing. In light of the energy landscape, it is suggested that the deep energy level of the CT state relative to that of the triplet pair state makes the CT state actually serve as a trap state that cannot undergoes an intramolecular singlet fission process. These results provide guidance for the design of SF materials and highlight the requisite for more widely applicable design principles.

Economical and environmental analysis of thermal and photovoltaic solar energy as source of heat for industrial processes

NASA Astrophysics Data System (ADS)

Pérez-Aparicio, Elena; Lillo-Bravo, Isidoro; Moreno-Tejera, Sara; Silva-Pérez, Manuel

2017-06-01

Thermal energy for industrial processes can be generated using thermal (ST) or photovoltaic (PV) solar energy. ST energy has traditionally been the most favorable option due to its cost and efficiency. Current costs and efficiencies values make the PV solar energy become an alternative to ST energy as supplier of industrial process heat. The aim of this study is to provide a useful tool to decide in each case which option is economically and environmentally the most suitable alternative. The methodology used to compare ST and PV systems is based on the calculation of the levelized cost of energy (LCOE) and greenhouse gas emissions (GHG) avoided by using renewable technologies instead of conventional sources of energy. In both cases, these calculations depend on costs and efficiencies associated with ST or PV systems and the conversion factor from thermal or electrical energy to GHG. To make these calculations, a series of hypotheses are assumed related to consumer and energy prices, operation, maintenance and replacement costs, lifetime of the system or working temperature of the industrial process. This study applies the methodology at five different sites which have been selected taking into account their radiometric and meteorological characteristics. In the case of ST energy three technologies are taken into account, compound parabolic concentrator (CPC), linear Fresnel collector (LFC) and parabolic trough collector (PTC). The PV option includes two ways of use of generated electricity, an electrical resistance or a combination of an electrical resistance and a heat pump (HP). Current values of costs and efficiencies make ST system remains as the most favorable option. These parameters may vary significantly over time. The evolution of these parameters may convert PV systems into the most favorable option for particular applications.

Energy dissipation in the blade tip region of an axial fan

NASA Astrophysics Data System (ADS)

Bizjan, B.; Milavec, M.; Širok, B.; Trenc, F.; Hočevar, M.

2016-11-01

A study of velocity and pressure fluctuations in the tip clearance flow of an axial fan is presented in this paper. Two different rotor blade tip designs were investigated: the standard one with straight blade tips and the modified one with swept-back tip winglets. Comparison of integral sound parameters indicates a significant noise level reduction for the modified blade tip design. To study the underlying mechanisms of the energy conversion and noise generation, a novel experimental method based on simultaneous measurements of local flow velocity and pressure has also been developed and is presented here. The method is based on the phase space analysis by the use of attractors, which enable more accurate identification and determination of the local flow structures and turbulent flow properties. Specific gap flow energy derived from the pressure and velocity time series was introduced as an additional attractor parameter to assess the flow energy distribution and dissipation within the phase space, and thus determines characteristic sources of the fan acoustic emission. The attractors reveal a more efficient conversion of the pressure to kinetic flow energy in the case of the modified (tip winglet) fan blade design, and also a reduction in emitted noise levels. The findings of the attractor analysis are in a good agreement with integral fan characteristics (efficiency and noise level), while offering a much more accurate and detailed representation of gap flow phenomena.

Solid State Lighting: A Nanoenabled Case Study in Sustainability

NASA Astrophysics Data System (ADS)

Hicks, Andrea L.

This work uses three household lighting technology options (incandescent, compact fluorescent (CFL), and light emitting diode (LED)) in a nanoenabled case study of artificial lighting. Life cycle assessment (LCA) is used to analyze the environmental impact of three lighting types across all four lifecycle phases: raw materials acquisition, manufacturing, use, and end of life. Using the average United States electricity profile, the use phase is found to have the greatest impact in all nine impact categories defined by TRACI (Tool for the Reduction and Assessment of Chemical and other environmental Impacts). Agent based modeling (ABM) is used to further investigate the use phase with respect to the adoption of energy efficient lighting and the rebound effect. Survey data on the consumer adoption and use of energy efficient lighting technology yields insight into consumer actions and the potential for rebound to occur, and is used to inform the ABM. Based on the results of the ABM analysis it is suggested that regardless of the type of energy efficient lighting, as long as the consumption of light continues to increase, efficiency alone will not reduce energy consumption. Over extended periods of time (~70 years), energy consumption rebounds to levels of pre-efficiency periods. There is a need for policy measures that are coupled with efficiency increases in such a way that energy savings are sustainable. Geographical and temporal variations in electricity profiles and their associated impacts are explored using LCA. It is found that there is the potential for significant variation in the lifetime environmental impact of lighting options based on shifts in the electricity profile. These results suggest the need for effective local policy in coordination with flexible national policy.

Design and Development of a Residential Gas-Fired Heat Pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vineyard, Edward Allan; Abu-Heiba, Ahmad; Mahderekal, Dr. Isaac

2017-01-01

Heating, ventilating, and air-conditioning equipment consumes 43% of the total primary energy consumption in U.S. households. Presently, conventional gas furnaces have maximum heating efficiencies of 98%. Electric air conditioners used in association with the furnace for cooling have a minimum seasonal energy efficiency ratio (SEER) of 14.0. A residential gas-fired heat pump (RGHP) was developed and tested under standard rating conditions, resulting in a significant increase in heating efficiency of over 40% versus conventional natural gas furnaces. The associated efficiency of the RGHP in cooling mode is comparable in efficiency to an electric air conditioner (14.0 SEER) when compared onmore » a primary energy basis. The RGHP is similar in nature to a conventional heat pump but with two main differences. First, the primary energy savings are higher, based on a site versus source comparison, as the result of using natural gas to supply shaft power to the compressor rather than an electric motor. Second, waste heat is recovered from the engine to supplement space heating and reduce the energy input. It can also be used to provide supplemental water heating. The system utilizes a programmable logic controller that allows variable-speed operation to achieve improved control to meet building loads. RGHPs significantly reduce peak electric use during periods of high demand, especially peak summer loads, as well as peak winter loads in regions with widespread use of electric heating. This contributes to leveling year-round gas loads, with the potential to increase annual gas demand in some regions. The widespread adoption of RGHPs will contribute to significant reductions in primary energy consumption and carbon emissions through improved efficiencies.« less

Air flow optimization for energy efficient blower of biosafety cabinet class II A2

NASA Astrophysics Data System (ADS)

Ibrahim, M. D.; Mohtar, M. Z.; Alias, A. A.; Wong, L. K.; Yunos, Y. S.; Rahman, M. R. A.; Zulkharnain, A.; Tan, C. S.; Thayan, R.

2017-04-01

An energy efficient Biosafety Cabinet (BSC) has become a big challenge for manufacturers to develop BSC with the highest level of protection. The objective of research is to increase air flow velocity discharge from centrifugal blower. An aerodynamic duct shape inspired by the shape of Peregrine Falcon’s wing during diving flight is added to the end of the centrifugal blower. Investigation of air movement is determined by computational fluid dynamics (CFD) simulation. The results showed that air velocity can be increased by double compared to typical manufactured BSC and no air recirculation. As conclusion, a novel design of aerodynamic duct shape successfully developed and proved that air velocity can be increase naturally with same impeller speed. It can contribute in increasing energy efficiency of the centrifugal blower. It is vital to BSC manufacturer and can be apply to Heating, Air Ventilation and Air Conditioning (HVAC) industries.

Nomogram Method as Means for Resource Potential Efficiency Predicative Aid of Petrothermal Energy

NASA Astrophysics Data System (ADS)

Gabdrakhmanova, K. F.; Izmailova, G. R.; Larin, P. A.; Vasilyeva, E. R.; Madjidov, M. A.; Marupov, S. R.

2018-05-01

The article describes the innovative approach when predicting the resource potential efficiency of petrothermal energy. Various geothermal gradients representative of Bashkortostan and Tatarstan republics regions were considered. With the help of nomograms, the authors analysed fluid temperature dependency graphs at the outlet and the thermal power versus fluid velocity along the wellbore. From the family of graphs plotted by us, velocities corresponding to specific temperature were found. Then, according to thermal power versus velocity curve, power levels corresponding to these velocities relative to the selected fluid temperature were found. On the basis of two dependencies obtained, nomograms were plotted. The result of determining the petrothermal energy production efficiency is a family of isocline lines that enables one to select the optimum temperature and injection rate to obtain the required amount of heat for a particular depth and geothermal gradient.

Definition of Static Voltage Characteristics of the Motor Load for the Purpose of Increase in Energy Efficiency of Coal Mines of Kuzbass

NASA Astrophysics Data System (ADS)

Nepsha, Fedor; Efremenko, Vladimir

2017-11-01

The task of determining the static load characteristics is one of the most important tasks, the solution of which is necessary for the correct development of measures to increase the energy efficiency of the Kuzbass coal mines. At present, the influence of electric receivers on the level of consumption of active and reactive power is not taken into account, therefore, the proposed measures to increase the energy efficiency are not optimal. The article analyzes the L-shaped and T-shaped circuit for the replacement of an asynchronous motor (AM), according to the results of which it is determined that the T-shaped replacement scheme is the most accurate for determination of static load characteristics. The authors proposed and implemented in the MATLAB Simulink environment an algorithm for determining the static voltage characteristics of the motor load.

Walking efficiency before and after total hip replacement.

PubMed

Brown, M; Hislop, H J; Waters, R L; Porell, D

1980-10-01

The energy cost of walking and gait characteristics of patients with hip disease were studied to determine changes in walking efficiency following total hip replacement. Twenty-nine patients, 24 with unilateral hip disease and 5 with bilateral hip disease, were tested preoperatively and at various times postoperatively. Oxygen uptake was measured by a modified Douglas bag procedure. The temporal and distance characteristics of gait were measured with contact closing heel switches. Results showed postoperative increases in velocity, cadence, and stride length in patients with unilateral disease and with bilateral disease with bilateral replacement. After surgery, energy cost tended toward more normal levels, but the subjects were not within normal limits for oxygen uptake per minute, oxygen uptake per distance walked, or percent of predicted maximum aerobic capacity. Comparison of energy expenditure data with temporal and distance factors of gait indicated that all subjects became more physiologically efficient after hip replacement.

Leveraging Human-environment Systems in Residential Buildings for Aggregate Energy Efficiency and Sustainability

NASA Astrophysics Data System (ADS)

Xu, Xiaoqi

Reducing the energy consumed in the built environment is a key objective in many sustainability initiatives. Existing energy saving methods have consisted of physical interventions to buildings and/or behavioral modifications of occupants. However, such methods may not only suffer from their own disadvantages, e.g. high cost and transient effect, but also lose aggregate energy saving potential due to the oftentimes-associated single-building-focused view and an isolated examination of occupant behaviors. This dissertation attempts to overcome the limitations of traditional energy saving research and practical approaches, and enhance residential building energy efficiency and sustainability by proposing innovative energy strategies from a holistic perspective of the aggregate human-environment systems. This holistic perspective features: (1) viewing buildings as mutual influences in the built environment, (2) leveraging both the individual and contextualized social aspects of occupant behaviors, and (3) incorporating interactions between the built environment and human behaviors. First, I integrate three interlinked components: buildings, residents, and the surrounding neighborhood, and quantify the potential energy savings to be gained from renovating buildings at the inter-building level and leveraging neighborhood-contextualized occupant social networks. Following the confirmation of both the inter-building effect among buildings and occupants' interpersonal influence on energy conservation, I extend the research further by examining the synergy that may exist at the intersection between these "engineered" building networks and "social" peer networks, focusing specifically on the additional energy saving potential that could result from interactions between the two components. Finally, I seek to reach an alignment of the human and building environment subsystems by matching the thermostat preferences of each household with the thermal conditions within their apartment, and develop the Energy Saving Alignment Strategy to be considered in public housing assignment policy. This strategy and the inter-building level energy management strategies developed in my preceding research possess large-scale cost-effectiveness and may engender long-lasting influence compared with existing energy saving approaches. Building from the holistic framework of coupled human-environment systems, the findings of this research will advance knowledge of energy efficiency in the built environment and lead to the development of novel strategies to conserve energy in residential buildings.

The efficiency of utilization of metabolizable energy and apparent absorption of amino acids in sheep given spring- and autumn-harvested dried grass.

PubMed

Macrae, J C; Smith, J S; Dewey, P J; Brewer, A C; Brown, D S; Walker, A

1985-07-01

Three experiments were conducted with sheep given spring-harvested dried grass (SHG) and autumn-harvested dried grass (AHG). The first was a calorimetric trial to determine the metabolizable energy (ME) content of each grass and the efficiency with which sheep utilize their extra ME intakes above the maintenance level of intake. The second examined the relative amounts of extra non-ammonia-nitrogen (NAN) and individual amino acids absorbed from the small intestine per unit extra ME intake as the level of feeding was raised from energy equilibrium (M) to approximately 1.5 M. The third was a further calorimetric trial to investigate the effect of an abomasal infusion of 30 g casein/d on the efficiency of utilization of AHG. The ME content of the SHG (11.8 MJ/kg dry matter (DM] was higher than that of AHG (10.0 MJ/kg DM). The efficiency of utilization of ME for productive purposes (i.e. above the M level of intake; kf) was higher when given SHG (kf 0.54 between M and 2 M) than when given AHG (kf 0.43 between M and 2 M). As the level of intake of each grass was raised from M to 1.5 M there was a greater increment in the amounts of NAN (P less than 0.001) and the total amino acid (P less than 0.05) absorbed from the small intestines when sheep were given the SHG (NAN absorption, SHG 5.4 g/d, AHG 1.5 g/d, SED 0.54; total amino acid absorption SHG 31.5 g/d, AHG 14.3 g/d, SED 5.24). Infusion of 30 g casein/d per abomasum of sheep given AHG at M and 1.5 M levels of intake increased (P less than 0.05) the efficiency of utilization of the herbage from kf 0.45 to kf 0.57. Consideration is given to the possibility that the higher efficiency of utilization of ME in sheep given SHG may be related to the amounts of extra glucogenic amino acids absorbed from the small intestine which provide extra reducing equivalents (NADPH) and glycerol phosphate necessary for the conversion of acetate into fatty acids.

The Energy Maintenance Theory of Aging: Maintaining Energy Metabolism to Allow Longevity.

PubMed

Chaudhari, Snehal N; Kipreos, Edward T

2018-06-14

Fused, elongated mitochondria are more efficient in generating ATP than fragmented mitochondria. In diverse C. elegans longevity pathways, increased levels of fused mitochondria are associated with lifespan extension. Blocking mitochondrial fusion in these animals abolishes their extended longevity. The long-lived C. elegans vhl-1 mutant is an exception that does not have increased fused mitochondria, and is not dependent on fusion for longevity. Loss of mammalian VHL upregulates alternate energy generating pathways. This suggests that mitochondrial fusion facilitates longevity in C. elegans by increasing energy metabolism. In diverse animals, ATP levels broadly decreases with age. Substantial evidence supports the theory that increasing or maintaining energy metabolism promotes the survival of older animals. Increased ATP levels in older animals allow energy-intensive repair and homeostatic mechanisms such as proteostasis that act to prevent cellular aging. These observations support the emerging paradigm that maintaining energy metabolism promotes the survival of older animals. © 2018 WILEY Periodicals, Inc.

Quantum Dot Light-Emitting Devices: Beyond Alignment of Energy Levels

DOE PAGES

Zaiats, Gary; Ikeda, Shingo; Kinge, Sachin; ...

2017-08-25

Multinary semiconductor nanoparticles such as CuInS 2, AgInS 2, and the corresponding alloys with ZnS hold promise for designing future quantum dot light-emitting devices (QLED). The QLED architectures require matching of energy levels between the different electron and hole transport layers. In addition to energy level alignment, conductivity and charge transfer interactions within these layers determine the overall efficiency of QLED. By employing CuInS 2-ZnS QDs we succeeded in fabricating red-emitting QLED using two different hole-transporting materials, polyvinylcarbazole and poly(4- butylphenyldiphenylamine). Despite the similarity of the HOMO-LUMO energy levels of these two hole transport materials, the QLED devices exhibit distinctlymore » different voltage dependence. The difference in onset voltage and excited state interactions shows the complexity involved in selecting the hole transport materials for display devices.« less

Quantum Dot Light-Emitting Devices: Beyond Alignment of Energy Levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaiats, Gary; Ikeda, Shingo; Kinge, Sachin

Multinary semiconductor nanoparticles such as CuInS 2, AgInS 2, and the corresponding alloys with ZnS hold promise for designing future quantum dot light-emitting devices (QLED). The QLED architectures require matching of energy levels between the different electron and hole transport layers. In addition to energy level alignment, conductivity and charge transfer interactions within these layers determine the overall efficiency of QLED. By employing CuInS 2-ZnS QDs we succeeded in fabricating red-emitting QLED using two different hole-transporting materials, polyvinylcarbazole and poly(4- butylphenyldiphenylamine). Despite the similarity of the HOMO-LUMO energy levels of these two hole transport materials, the QLED devices exhibit distinctlymore » different voltage dependence. The difference in onset voltage and excited state interactions shows the complexity involved in selecting the hole transport materials for display devices.« less

Software augmented buildings: Exploiting existing infrastructure to improve energy efficiency and comfort in commercial buildings

NASA Astrophysics Data System (ADS)

Balaji, Bharathan

Commercial buildings consume 19% of energy in the US as of 2010, and traditionally, their energy use has been optimized through improved equipment efficiency and retrofits. Beyond improved hardware and infrastructure, there exists a tremendous potential in reducing energy use through better monitoring and operation. We present several applications that we developed and deployed to support our thesis that building energy use can be reduced through sensing, monitoring and optimization software that modulates use of building subsystems including HVAC. We focus on HVAC systems as these constitute 48-55% of building energy use. Specifically, in case of sensing, we describe an energy apportionment system that enables us to estimate real-time zonal HVAC power consumption by analyzing existing sensor information. With this energy breakdown, we can measure effectiveness of optimization solutions and identify inefficiencies. Central to energy efficiency improvement is determination of human occupancy in buildings. But this information is often unavailable or expensive to obtain using wide scale sensor deployment. We present our system that infers room level occupancy inexpensively by leveraging existing WiFi infrastructure. Occupancy information can be used not only to directly control HVAC but also to infer state of the building for predictive control. Building energy use is strongly influenced by human behaviors, and timely feedback mechanisms can encourage energy saving behavior. Occupants interact with HVAC using thermostats which has shown to be inadequate for thermal comfort. Building managers are responsible for incorporating energy efficiency measures, but our interviews reveal that they struggle to maintain efficiency due to lack of analytical tools and contextual information. We present our software services that provide energy feedback to occupants and building managers, improves comfort with personalized control and identifies energy wasting faults. For wide scale deployment of such energy saving software, they need to be portable across multiple buildings. However, buildings consist of heterogeneous equipment and use inconsistent naming schema, and developers need extensive domain knowledge to map sensor information to a standard format. To enable portability, we present an active learning algorithm that automates mapping building sensor metadata to a standard naming schema.

Energy Efficient Demonstration Proves Powerful in Home Retrofits -

Science.gov Websites

project team that included key Navy stakeholders at the regional and Naval Base Guam installation levels was Naval Base Guam in Apra Harbor, which has 1,369 houses for its active-duty Navy and family members millions." Given Naval Base Guam's high electricity rates of $0.50 per kilowatt hour, the efficiency

Photovoltaics: Reviewing the European Feed-in-Tariffs and Changing PV Efficiencies and Costs

PubMed Central

Zhang, H. L.; Van Gerven, T.; Baeyens, J.; Degrève, J.

2014-01-01

Feed-in-Tariff (FiT) mechanisms have been important in boosting renewable energy, by providing a long-term guaranteed subsidy of the kWh-price, thus mitigating investment risks and enhancing the contribution of sustainable electricity. By ongoing PV development, the contribution of solar power increases exponentially. Within this significant potential, it is important for investors, operators, and scientists alike to provide answers to different questions related to subsidies, PV efficiencies and costs. The present paper therefore (i) briefly reviews the mechanisms, advantages, and evolution of FiT; (ii) describes the developments of PV, (iii) applies a comprehensive literature-based model for the solar irradiation to predict the PV solar energy potential in some target European countries, whilst comparing output predictions with the monthly measured electricity generation of a 57 m² photovoltaic system (Belgium); and finally (iv) predicts the levelized cost of energy (LCOE) in terms of investment and efficiency, providing LCOE values between 0.149 and 0.313 €/kWh, as function of the overall process efficiency and cost. The findings clearly demonstrate the potential of PV energy in Europe, where FiT can be considerably reduced or even be eliminated in the near future. PMID:24959614

Thermoelectrics as elements of hybrid-electric vehicle thermal energy systems

NASA Astrophysics Data System (ADS)

Headings, Leon; Washington, Gregory; Jaworski, Christopher M.

2008-03-01

Despite vast technological improvements, the traditional internal combustion powered vehicle still achieves only 25- 30% efficiency, with the remainder lost primarily as heat. While the load leveling offered by hybrid-electric vehicle technology helps to improve this overall efficiency, part of the efficiency gains are achieved by making new systems such as regenerative braking viable. In a similar fashion, thermoelectric (TE) energy recovery has long been considered for traditional vehicles with mixed results, but little has been done to consider thermoelectrics in the framework of the unique energy systems of hybrid vehicles. Systems that may not have been viable or even possible with traditional vehicles may offer improvements to system efficiency as well as emissions, vehicle durability, passenger comfort, and cost. This research describes a simulation developed for evaluating and optimizing thermoelectric energy recovery systems and results for four different system configurations. Two novel system configurations are presented which offer the potential for additional benefits such as emissions reduction that will soon be quantified. In addition, a test setup is presented which was constructed for the testing and validation of various thermoelectric recovery systems. Actual test performance was near the expected theoretical performance and supported the conclusions reached from the computer simulations.

Energy conservation and management system using efficient building automation

NASA Astrophysics Data System (ADS)

Ahmed, S. Faiz; Hazry, D.; Tanveer, M. Hassan; Joyo, M. Kamran; Warsi, Faizan A.; Kamarudin, H.; Wan, Khairunizam; Razlan, Zuradzman M.; Shahriman A., B.; Hussain, A. T.

2015-05-01

In countries where the demand and supply gap of electricity is huge and the people are forced to endure increasing hours of load shedding, unnecessary consumption of electricity makes matters even worse. So the importance and need for electricity conservation increases exponentially. This paper outlines a step towards the conservation of energy in general and electricity in particular by employing efficient Building Automation technique. It should be noted that by careful designing and implementation of the Building Automation System, up to 30% to 40% of energy consumption can be reduced, which makes a huge difference for energy saving. In this study above mentioned concept is verified by performing experiment on a prototype experimental room and by implementing efficient building automation technique. For the sake of this efficient automation, Programmable Logic Controller (PLC) is employed as a main controller, monitoring various system parameters and controlling appliances as per required. The hardware test run and experimental findings further clarifies and proved the concept. The added advantage of this project is that it can be implemented to both small and medium level domestic homes thus greatly reducing the overall unnecessary load on the Utility provider.

Mecanismes physiques et fondements theoriques de la recuperation d'energie micro-ondes ambiante pour les dispositifs sans fil a faible consommation

NASA Astrophysics Data System (ADS)

Petzl Lorenz, Carlos Henrique

Powering low consumption and low duty cycle devices and circuits using Ambient Microwave Energy Harvesting (AMEH) has been the subject of several investigations in recent years. The interest for this research topic has been promoted mainly by various and new applications driven mainly by the Internet of things, Building Automation and new developments in devices for the Body Area Networks. A common characteristic among several of these applications is the need for a wireless source which does not require regular maintenance, and has a small size and low weight. Batteries are often too cumbersome and require a maintenance plan to recharge or replace them, which is not always possible. A new source of energy is thus necessary. Ambient energy harvesting is proposed as an alternative source of power to these low power consumption devices and circuits. This M.A.Sc. work is developed to explore the microwave ambient energy harvesting using diode rectifier circuits. A mathematical model is first developed to explain the mechanisms that contribute to the process of recovery of microwave energy in the range of power found in the ambient microwave energy harvesting applications. An evaluation of this model is made using simulation results and then measurements results from three prototypes developed under this M.A.Sc. program. The results show an excellent agreement between the three methods. The developed model includes losses in the parasitic components of the non-linear element used for the rectification of energy as well as the impedance matching network insertion losses. Based on this model, two possible ways of improving the efficiency of ambient microwave power rectifiers at the power levels found in the AMEH are explored. In this work, it is considered that the AMEH takes place within the range of powers with a peak value of -30 dBm, however at average power levels well below this threshold. First, a cooperative hybrid circuit of ambient energy harvesting is presented where collected microwave and mechanical energies are converted in a cooperative manner through a single nonlinear component. Theory, simulations and measurements show that the total power recovered by the proposed scheme can provide up to twice the efficiency of a circuit combining the output of two independent harvesters. Then, a work demonstrating for the first time that the limitations of a Schottky diode harvester can be overcome by using backward tunnel diodes is presented. It is shown that the limitation reached by the Schottky diodes half a century ago can be overcome thanks to a higher current responsivity obtained through tunneling transport. The measured power recovery efficiency was equal to 18.2% when a -30 dBm signal at 2.4 GHz was applied to the input of the microwave energy harvesting circuit. The efficiency of conversion for a similar circuit using Schottky diodes, which is presented in the first chapter together with the mathematical model, does not exceed 11% at the same input power level and similar frequency. On the date of publication of the articles presented in this thesis, the highest published microwave power conversion efficiency was close to 5% for input power levels equal to -30 dBm and frequency close to 2 GHz. Finally, an application of microwave power transfer is presented. A rectenna operating at 94 GHz is built and measured, an energy conversion efficiency equal to 37.7% was obtained for an input power equal to 3 dBm. This rectenna is proposed as an alternative power source for microrobots, which may not use batteries due to their small size and light weight.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The report is an overview of electric energy efficiency programs. It takes a concise look at what states are doing to encourage energy efficiency and how it impacts electric utilities. Energy efficiency programs began to be offered by utilities as a response to the energy crises of the 1970s. These regulatory-driven programs peaked in the early-1990s and then tapered off as deregulation took hold. Today, rising electricity prices, environmental concerns, and national security issues have renewed interest in increasing energy efficiency as an alternative to additional supply. In response, new methods for administering, managing, and delivering energy efficiency programs aremore » being implemented. Topics covered in the report include: Analysis of the benefits of energy efficiency and key methods for achieving energy efficiency; evaluation of the business drivers spurring increased energy efficiency; Discussion of the major barriers to expanding energy efficiency programs; evaluation of the economic impacts of energy efficiency; discussion of the history of electric utility energy efficiency efforts; analysis of the impact of energy efficiency on utility profits and methods for protecting profitability; Discussion of non-utility management of energy efficiency programs; evaluation of major methods to spur energy efficiency - systems benefit charges, resource planning, and resource standards; and, analysis of the alternatives for encouraging customer participation in energy efficiency programs.« less

Flat-plate solar array project. Volume 4: High-efficiency solar cells

NASA Technical Reports Server (NTRS)

Leipold, M.; Cheng, L.; Daud, T.; Mokashi, A.; Burger, D.; Christensen, E. (Editor); Murry, J. (Editor); Bengelsdorf, I. (Editor)

1986-01-01

The High Efficiency Solar Cell Task was assigned the objective of understanding and developing high efficiency solar cell devices that would meet the cost and performance goals of the Flat Plate Solar Array (FSA) Project. The need for research dealing with high efficiency devices was considered important because of the role efficiency plays in reducing price per watt of generated energy. The R&D efforts conducted during the 1982 to 1986 period are summarized to provide understanding and control of energy conversion losses associated with crystalline silicon solar cells. New levels of conversion efficiency were demonstrated. Major contributions were made both to the understanding and reduction of bulk and surface losses in solar cells. For example, oxides, nitrides, and polysilicon were all shown to be potentially useful surface passivants. Improvements in measurement techniques were made and Auger coefficients and spectral absorption data were obtained for unique types of silicon sheets. New modelling software was developed including a program to optimize a device design based on input characteristics of a cell.

Innovative, energy-efficient lighting for New York state roadways : opportunities for incorporating mesopic visibility considerations into roadway lighting practice

DOT National Transportation Integrated Search

2008-04-01

The present report outlines activities undertaken to assess the potential for implementing research on visibility at mesopic light levels into lighting practices for roadways in New York State. Through measurements of light levels at several roadway ...

Performance of the CELSS Antarctic Analog Project (CAAP) Crop Production System

NASA Technical Reports Server (NTRS)

Bubenheim, David L.; Flynn, Michael T.; Bates, Maynard; Schlick, Greg; Kliss, Mark (Technical Monitor)

1998-01-01

Regenerative life support systems potentially offer a level of self-sufficiency and a concomitant decrease in logistics and associated costs in support of space exploration and habitation missions. Current state-of-the-art in plant based, regenerative life support requires resources in excess of resource allocations proposed for candidate mission scenarios. Feasibility thresholds have been identified for candidate exploration missions. The goal of this paper is to review recent advances in performance achieved in the CELSS Antarctic Analog Project (CAAP) in light of likely resource constraints. A prototype CAAP crop production chamber has been constructed and operated at the Ames Research Center. The chamber includes a number of unique hardware and software components focused on attempts to increase production efficiency, increase energy efficiency, and control the flow of energy and mass through the system to achieve enhanced performance efficiency. Both single crop, batch production, and continuous cultivation of mixed crops Product ion scenarios have been completed. The crop productivity as well as engineering performance of the chamber will be described. For each scenario, energy required and partitioned for lighting, cooling, pumps, fans, etc. is quantified. Crop production and the resulting lighting efficiency and energy conversion efficiencies are presented. In the mixed-crop scenario, with up to 25 different crops under cultivation, 17 sq m of crop area provided a mean of 515 g edible biomass per day (83% of the approximately 620 g required for one person). Lighting efficiency (moles on photons kWh-1) approached 4 and the conversion efficiency of light energy to biomass was greatly enhanced compared with conventional growing systems. Engineering and biological performance achieved place plant-based life support systems at the threshold of feasibility.

Optimal quantum operations at zero energy cost

NASA Astrophysics Data System (ADS)

Chiribella, Giulio; Yang, Yuxiang

2017-08-01

Quantum technologies are developing powerful tools to generate and manipulate coherent superpositions of different energy levels. Envisaging a new generation of energy-efficient quantum devices, here we explore how coherence can be manipulated without exchanging energy with the surrounding environment. We start from the task of converting a coherent superposition of energy eigenstates into another. We identify the optimal energy-preserving operations, both in the deterministic and in the probabilistic scenario. We then design a recursive protocol, wherein a branching sequence of energy-preserving filters increases the probability of success while reaching maximum fidelity at each iteration. Building on the recursive protocol, we construct efficient approximations of the optimal fidelity-probability trade-off, by taking coherent superpositions of the different branches generated by probabilistic filtering. The benefits of this construction are illustrated in applications to quantum metrology, quantum cloning, coherent state amplification, and ancilla-driven computation. Finally, we extend our results to transitions where the input state is generally mixed and we apply our findings to the task of purifying quantum coherence.

Airflow energy harvesting with high wind velocities for industrial applications

NASA Astrophysics Data System (ADS)

Chew, Z. J.; Tuddenham, S. B.; Zhu, M.

2016-11-01

An airflow energy harvester capable of harvesting energy from vortices at high speed is presented in this paper. The airflow energy harvester is implemented using a modified helical Savonius turbine and an electromagnetic generator. A power management module with maximum power point finding capability is used to manage the harvested energy and convert the low voltage magnitude from the generator to a usable level for wireless sensors. The airflow energy harvester is characterized using vortex generated by air hitting a plate in a wind tunnel. By using an aircraft environment with wind speed of 17 m/s as case study, the output power of the airflow energy harvester is measured to be 126 mW. The overall efficiency of the power management module is 45.76 to 61.2%, with maximum power point tracking efficiency of 94.21 to 99.72% for wind speed of 10 to 18 m/s, and has a quiescent current of 790 nA for the maximum power point tracking circuit.

Towards energy-efficient nonoscillatory forward-in-time integrations on lat-lon grids

NASA Astrophysics Data System (ADS)

Polkowski, Marcin; Piotrowski, Zbigniew; Ryczkowski, Adam

2017-04-01

The design of the next-generation weather prediction models calls for new algorithmic approaches allowing for robust integrations of atmospheric flow over complex orography at sub-km resolutions. These need to be accompanied by efficient implementations exposing multi-level parallelism, capable to run on modern supercomputing architectures. Here we present the recent advances in the energy-efficient implementation of the consistent soundproof/implicit compressible EULAG dynamical core of the COSMO weather prediction framework. Based on the experiences of the atmospheric dwarfs developed within H2020 ESCAPE project, we develop efficient, architecture agnostic implementations of fully three-dimensional MPDATA advection schemes and generalized diffusion operator in curvilinear coordinates and spherical geometry. We compare optimized Fortran implementation with preliminary C++ implementation employing the Gridtools library, allowing for integrations on CPU and GPU while maintaining single source code.

Operational Energy Metrics: Increasing Flexibility While Reducing Vulnerability

DTIC Science & Technology

2010-03-01

procurement decisions with a greater level of fidelity concerning the cost- benefit analysis for systems lifetime cost of energy. Furthermore, it...or we have to RTB, we’re BINGO -fuel48”? As General Ronald Keys, USAF (RET.) stated when discussing energy efficiency and mission effectiveness...of Defense change to fully value the delivered cost of fuel, the sooner joint force commanders will reap the “strategic benefits of reallocating

Current status and future prospects of power generators using dielectric elastomers

NASA Astrophysics Data System (ADS)

Chiba, Seiki; Waki, Mikio; Kornbluh, Roy; Pelrine, Ron

2011-12-01

Electroactive polymer artificial muscle (EPAM), known collectively as dielectric elastomers in the literature, has been shown to offer unique capabilities as an actuator and is now being developed for a wide variety of generator applications. EPAM has several characteristics that make it potentially well suited for wave, water current, wind, human motion, and other environmental energy harvesting systems including a high energy density allowing for minimal EPAM material quantities, high energy conversion efficiency independent of frequency of operation and non-toxic and low-cost materials not susceptible to corrosion. Experiments have been performed on push-button and heel-mounted generator devices powered by human motion, ocean wave power harvesters mounted on buoys and water turbines. While the power output levels of such demonstration devices is small, the performance of these devices has supported the potential benefits of EPAM. For example, an electrical energy conversion efficiency of over 70% was achieved with small wave heights. The ability of EPAM to produce hydrogen fuel for energy storage was also demonstrated. Because the energy conversion principle of EPAM is capacitive in nature, the performance is largely independent of size and it should eventually be possible to scale up EPAM generators to the megawatt level to address a variety of electrical power needs.

Intermediate Band Gap Solar Cells: The Effect of Resonant Tunneling on Delocalization

NASA Astrophysics Data System (ADS)

William, Reid; Mathew, Doty; Sanwli, Shilpa; Gammon, Dan; Bracker, Allan

2011-03-01

Quantum dots (QD's) have many unique properties, including tunable discrete energy levels, that make them suitable for a variety of next generation photovoltaic applications. One application is an intermediate band solar cell (IBSC); in which QD's are incorporated into the bulk material. The QD's are tuned to absorb low energy photons that would otherwise be wasted because their energy is less than the solar cell's bulk band gap. Current theory concludes that identical QD's should be arranged in a superlattice to form a completely delocalized intermediate band maximizing absorption of low energy photons while minimizing the decrease in the efficiency of the bulk material. We use a T-matrix model to assess the feasibility of forming a delocalized band given that real QD ensembles have an inhomogeneous distribution of energy levels. Our results suggest that formation of a band delocalized through a large QD superlattice is challenging; suggesting that the assumptions underlying present IBSC theory require reexamination. We use time-resolved photoluminescence of coupled QD's to probe the effect of delocalized states on the dynamics of absorption, energy transport, and nonradiative relaxation. These results will allow us to reexamine the theoretical assumptions and determine the degree of delocalization necessary to create an efficient quantum dot-based IBSC.

Refurbishment of a Victorian terraced house for energy efficiency

NASA Astrophysics Data System (ADS)

Dimitriou, Angeliki

The impacts of global warming are now obvious. The international community has committed itself to reduce CO2 emissions, the main contributor to the greenhouse effect, both at international and national levels. In the Kyoto Protocol signed in 1997, countries have committed to reduce their greenhouse gases emissions below their 1990 levels by the period 2008-2012. The UK specifically should reduce those emissions by 12.5%. Format reason, the UK has introduced a package of policies, which promote not only the use of renewable energy resources, but most importantly the reduction in energy use, with energy efficiency. Refurbishment of existing houses has and will contribute to the reduction of energy consumption. A Victorian mid-terraced house was studied in this report, and different refurbishment measures were tested, using two software programmes: TAS and SAP. The targets were to achieve certain levels of thermal comfort, to comply with the Building Regulation for building thermal elements and to achieve a high SAP rating. Then, the cost of each measure was calculated and its CO2 emissions were compared. Heat losses were mainly through the walls and roof. Roof and mainly wall refurbishment measures reduce the heating loads the most. Ground floor insulation does not contribute to the reduction of the heating loads, on the contrary it has detrimental effect in summer, where the cooling effect coming from the ground is being reduced. Window replacement achieves a very good performance in summer resulting in the reduction of overheating. Wall and roof insulation increase the SAP rating the most, between the building elements, but boiler replacement and upgrading of heating controls increase it more. According to the SAP rating, CO2 annual emissions are reduced the most by boiler replacement and then by wall and roof. The results given by the two softwares concerning which measure is more leads more to energy efficiency, are the same. Finally, if the measures which lead to the best energy performance are combined together, then the house could cut its energy bills by half, and could have 70% reduction in CO2 emissions.

Energy release for the actuation and deployment of muscle-inspired asymmetrically multistable chains

NASA Astrophysics Data System (ADS)

Kidambi, Narayanan; Zheng, Yisheng; Harne, Ryan L.; Wang, K. W.

2018-03-01

Animal locomotion and movement requires energy, and the elastic potential energy stored in skeletal muscle can facilitate movements that are otherwise energetically infeasible. A significant proportion of this energy is captured and stored in the micro- and nano-scale constituents of muscle near the point of instability between asymmetric equilibrium states. This energy may be quickly released to enable explosive macroscopic motions or to reduce the metabolic cost of cyclic movements. Inspired by these behaviors, this research explores modular metastructures of bistable element chains and develops methods to release the energy stored in higher-potential system configurations. Quasi-static investigations reveal the role of state-transition pathways on the overall efficiency of the deployment event. It is shown that sequential, local release of energy from the bistable elements is more efficient than concurrent energy release achieved by applying a force at the free end of the structure. From dynamic analyses and experiments, it is shown that that the energy released from one bistable element can be used to activate the release of energy from subsequent links, reducing the actuation energy required to extend or deploy the chain below that required for quasi-static deployment. This phenomenon is influenced by the level of asymmetry in the bistable constituents and the location of the impulse that initiates the deployment of the structure. The results provide insight into the design and behavior of asymmetrically multistable chains that can leverage stored potential energy to enable efficient and effective system deployment and length change.

Simulation of the outdoor energy efficiency of an autonomous solar kit based on meteorological data for a site in Central Europa

NASA Astrophysics Data System (ADS)

Bouzaki, Mohammed Moustafa; Chadel, Meriem; Benyoucef, Boumediene; Petit, Pierre; Aillerie, Michel

2016-07-01

This contribution analyzes the energy provided by a solar kit dedicated to autonomous usage and installed in Central Europa (Longitude 6.10°; Latitude 49.21° and Altitude 160 m) by using the simulation software PVSYST. We focused the analysis on the effect of temperature and solar irradiation on the I-V characteristic of a commercial PV panel. We also consider in this study the influence of charging and discharging the battery on the generator efficiency. Meteorological data are integrated into the simulation software. As expected, the solar kit provides an energy varying all along the year with a minimum in December. In the proposed approach, we consider this minimum as the lowest acceptable energy level to satisfy the use. Thus for the other months, a lost in the available renewable energy exists if no storage system is associated.

Investigation of applications for high-power, self-critical fissioning uranium plasma reactors

NASA Technical Reports Server (NTRS)

Rodgers, R. J.; Latham, T. S.; Krascella, N. L.

1976-01-01

Analytical studies were conducted to investigate potentially attractive applications for gaseous nuclear cavity reactors fueled by uranium hexafluoride and its decomposition products at temperatures of 2000 to 6000 K and total pressures of a few hundred atmospheres. Approximate operating conditions and performance levels for a class of nuclear reactors in which fission energy removal is accomplished principally by radiant heat transfer from the high temperature gaseous nuclear fuel to surrounding absorbing media were determined. The results show the radiant energy deposited in the absorbing media may be efficiently utilized in energy conversion system applications which include (1) a primary energy source for high thrust, high specific impulse space propulsion, (2) an energy source for highly efficient generation of electricity, and (3) a source of high intensity photon flux for heating working fluid gases for hydrogen production or MHD power extraction.

Energy Level Alignment at Aqueous GaN and ZnO Interfaces

NASA Astrophysics Data System (ADS)

Hybertsen, Mark S.; Kharche, Neerav; Muckerman, James T.

2014-03-01

Electronic energy level alignment at semiconductor-electrolyte interfaces is fundamental to electrochemical activity. Motivated in particular by the search for new materials that can be more efficient for photocatalysis, we develop a first principles method to calculate this alignment at aqueous interfaces and demonstrate it for the specific case of non-polar GaN and ZnO interfaces with water. In the first step, density functional theory (DFT) based molecular dynamics is used to sample the physical interface structure and to evaluate the electrostatic potential step at the interface. In the second step, the GW approach is used to evaluate the reference electronic energy level separately in the bulk semiconductor (valence band edge energy) and in bulk water (the 1b1 energy level), relative to the internal electrostatic energy reference. Use of the GW approach naturally corrects for errors inherent in the use of Kohn-Sham energy eigenvalues to approximate the electronic excitation energies in each material. With this predicted interface alignment, specific redox levels in water, with potentials known relative to the 1b1 level, can then be compared to the semiconductor band edge positions. Our results will be discussed in the context of experiments in which photoexcited GaN and ZnO drive the hydrogen evolution reaction. Research carried out at Brookhaven National Laboratory under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.

Solving employment problems in the European Union: The role of energy efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiltshire, V.

1998-07-01

This paper is based on a project funded under the European Commission's SAVE (Specific Actions for Vigorous Energy Efficiency) program. The project is looking at the employment implications of energy efficiency programs, using a large number of case studies throughout the nine European Union (EU) countries participating in the project. Various modeling techniques are being used to investigate policy scenarios. The EU is particularly interested in looking at employment potential of energy efficiency at the present time. Traditionally, jobs in the environmental sector have only been seen as occurring in end-of-pipe type industries, such as pollution control; but a largemore » potential for employment opportunities has now been recognized in the energy efficiency sector. Included in the study will be a detailed discussion of the quality, as well as the quantity, of jobs created, i.e. what skill levels will be required and the types of people who would wish to undertake the work. The qualitative aspect of jobs will be looked at for their suitability for solving EU and country specific problems, such as long term unemployment of unskilled workers. This paper will present some initial results from the study and discuss the issues raised by it and by other recent work in this area. Such issues include not only the types and numbers of jobs directly created through the programs, but also indirect effects on the local, national and international economies. The negative effects, such as the reduced energy usage effect on the supply industry will also be examined.« less

Energy efficient neural stimulation: coupling circuit design and membrane biophysics.

PubMed

Foutz, Thomas J; Ackermann, D Michael; Kilgore, Kevin L; McIntyre, Cameron C

2012-01-01

The delivery of therapeutic levels of electrical current to neural tissue is a well-established treatment for numerous indications such as Parkinson's disease and chronic pain. While the neuromodulation medical device industry has experienced steady clinical growth over the last two decades, much of the core technology underlying implanted pulse generators remain unchanged. In this study we propose some new methods for achieving increased energy-efficiency during neural stimulation. The first method exploits the biophysical features of excitable tissue through the use of a centered-triangular stimulation waveform. Neural activation with this waveform is achieved with a statistically significant reduction in energy compared to traditional rectangular waveforms. The second method demonstrates energy savings that could be achieved by advanced circuitry design. We show that the traditional practice of using a fixed compliance voltage for constant-current stimulation results in substantial energy loss. A portion of this energy can be recuperated by adjusting the compliance voltage to real-time requirements. Lastly, we demonstrate the potential impact of axon fiber diameter on defining the energy-optimal pulse-width for stimulation. When designing implantable pulse generators for energy efficiency, we propose that the future combination of a variable compliance system, a centered-triangular stimulus waveform, and an axon diameter specific stimulation pulse-width has great potential to reduce energy consumption and prolong battery life in neuromodulation devices.

The mechanics of explosive seed dispersal in orange jewelweed (Impatiens capensis)

PubMed Central

Hayashi, Marika; Feilich, Kara L.; Ellerby, David J.

2009-01-01

Explosive dehiscence ballistically disperses seeds in a number of plant species. During dehiscence, mechanical energy stored in specialized tissues is transferred to the seeds to increase their kinetic and potential energies. The resulting seed dispersal patterns have been investigated in some ballistic dispersers, but the mechanical performance of a launch mechanism of this type has not been measured. The properties of the energy storage tissue and the energy transfer efficiency of the launch mechanism were quantified in Impatiens capensis. In this species the valves forming the seed pod wall store mechanical energy. Their mass specific energy storage capacity (124 J kg−1) was comparable with that of elastin and spring steel. The energy storage capacity of the pod tissues was determined by their level of hydration, suggesting a role for turgor pressure in the energy storage mechanism. During dehiscence the valves coiled inwards, collapsing the pod and ejecting the seeds. Dehiscence took 4.2±0.4 ms (mean ±SEM, n=13). The estimated efficiency with which energy was transferred to the seeds was low (0.51±0.26%, mean ±SEM, n=13). The mean seed launch angle (17.4±5.2, mean ±SEM, n=45) fell within the range predicted by a ballistic model to maximize dispersal distance. Low ballistic dispersal efficiency or effectiveness may be characteristic of species that also utilize secondary seed dispersal mechanisms. PMID:19321647

The mechanics of explosive seed dispersal in orange jewelweed (Impatiens capensis).

PubMed

Hayashi, Marika; Feilich, Kara L; Ellerby, David J

2009-01-01

Explosive dehiscence ballistically disperses seeds in a number of plant species. During dehiscence, mechanical energy stored in specialized tissues is transferred to the seeds to increase their kinetic and potential energies. The resulting seed dispersal patterns have been investigated in some ballistic dispersers, but the mechanical performance of a launch mechanism of this type has not been measured. The properties of the energy storage tissue and the energy transfer efficiency of the launch mechanism were quantified in Impatiens capensis. In this species the valves forming the seed pod wall store mechanical energy. Their mass specific energy storage capacity (124 J kg(-1)) was comparable with that of elastin and spring steel. The energy storage capacity of the pod tissues was determined by their level of hydration, suggesting a role for turgor pressure in the energy storage mechanism. During dehiscence the valves coiled inwards, collapsing the pod and ejecting the seeds. Dehiscence took 4.2+/-0.4 ms (mean +/-SEM, n=13). The estimated efficiency with which energy was transferred to the seeds was low (0.51+/-0.26%, mean +/-SEM, n=13). The mean seed launch angle (17.4+/-5.2, mean +/-SEM, n=45) fell within the range predicted by a ballistic model to maximize dispersal distance. Low ballistic dispersal efficiency or effectiveness may be characteristic of species that also utilize secondary seed dispersal mechanisms.

Energy-aware Thread and Data Management in Heterogeneous Multi-core, Multi-memory Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Chun-Yi

By 2004, microprocessor design focused on multicore scaling—increasing the number of cores per die in each generation—as the primary strategy for improving performance. These multicore processors typically equip multiple memory subsystems to improve data throughput. In addition, these systems employ heterogeneous processors such as GPUs and heterogeneous memories like non-volatile memory to improve performance, capacity, and energy efficiency. With the increasing volume of hardware resources and system complexity caused by heterogeneity, future systems will require intelligent ways to manage hardware resources. Early research to improve performance and energy efficiency on heterogeneous, multi-core, multi-memory systems focused on tuning a single primitivemore » or at best a few primitives in the systems. The key limitation of past efforts is their lack of a holistic approach to resource management that balances the tradeoff between performance and energy consumption. In addition, the shift from simple, homogeneous systems to these heterogeneous, multicore, multi-memory systems requires in-depth understanding of efficient resource management for scalable execution, including new models that capture the interchange between performance and energy, smarter resource management strategies, and novel low-level performance/energy tuning primitives and runtime systems. Tuning an application to control available resources efficiently has become a daunting challenge; managing resources in automation is still a dark art since the tradeoffs among programming, energy, and performance remain insufficiently understood. In this dissertation, I have developed theories, models, and resource management techniques to enable energy-efficient execution of parallel applications through thread and data management in these heterogeneous multi-core, multi-memory systems. I study the effect of dynamic concurrent throttling on the performance and energy of multi-core, non-uniform memory access (NUMA) systems. I use critical path analysis to quantify memory contention in the NUMA memory system and determine thread mappings. In addition, I implement a runtime system that combines concurrent throttling and a novel thread mapping algorithm to manage thread resources and improve energy efficient execution in multi-core, NUMA systems.« less

Efficient Construction of Free Energy Profiles of Breathing Metal–Organic Frameworks Using Advanced Molecular Dynamics Simulations

PubMed Central

2017-01-01

In order to reliably predict and understand the breathing behavior of highly flexible metal–organic frameworks from thermodynamic considerations, an accurate estimation of the free energy difference between their different metastable states is a prerequisite. Herein, a variety of free energy estimation methods are thoroughly tested for their ability to construct the free energy profile as a function of the unit cell volume of MIL-53(Al). The methods comprise free energy perturbation, thermodynamic integration, umbrella sampling, metadynamics, and variationally enhanced sampling. A series of molecular dynamics simulations have been performed in the frame of each of the five methods to describe structural transformations in flexible materials with the volume as the collective variable, which offers a unique opportunity to assess their computational efficiency. Subsequently, the most efficient method, umbrella sampling, is used to construct an accurate free energy profile at different temperatures for MIL-53(Al) from first principles at the PBE+D3(BJ) level of theory. This study yields insight into the importance of the different aspects such as entropy contributions and anharmonic contributions on the resulting free energy profile. As such, this thorough study provides unparalleled insight in the thermodynamics of the large structural deformations of flexible materials. PMID:29131647

Efficient Construction of Free Energy Profiles of Breathing Metal-Organic Frameworks Using Advanced Molecular Dynamics Simulations.

PubMed

Demuynck, Ruben; Rogge, Sven M J; Vanduyfhuys, Louis; Wieme, Jelle; Waroquier, Michel; Van Speybroeck, Veronique

2017-12-12

In order to reliably predict and understand the breathing behavior of highly flexible metal-organic frameworks from thermodynamic considerations, an accurate estimation of the free energy difference between their different metastable states is a prerequisite. Herein, a variety of free energy estimation methods are thoroughly tested for their ability to construct the free energy profile as a function of the unit cell volume of MIL-53(Al). The methods comprise free energy perturbation, thermodynamic integration, umbrella sampling, metadynamics, and variationally enhanced sampling. A series of molecular dynamics simulations have been performed in the frame of each of the five methods to describe structural transformations in flexible materials with the volume as the collective variable, which offers a unique opportunity to assess their computational efficiency. Subsequently, the most efficient method, umbrella sampling, is used to construct an accurate free energy profile at different temperatures for MIL-53(Al) from first principles at the PBE+D3(BJ) level of theory. This study yields insight into the importance of the different aspects such as entropy contributions and anharmonic contributions on the resulting free energy profile. As such, this thorough study provides unparalleled insight in the thermodynamics of the large structural deformations of flexible materials.

Energy expenditure and activity of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees.

PubMed

Kaufman, Kenton R; Levine, James A; Brey, Robert H; McCrady, Shelly K; Padgett, Denny J; Joyner, Michael J

2008-07-01

To quantify the energy efficiency of locomotion and free-living physical activity energy expenditure of transfemoral amputees using a mechanical and microprocessor-controlled prosthetic knee. Repeated-measures design to evaluate comparative functional outcomes. Exercise physiology laboratory and community free-living environment. Subjects (N=15; 12 men, 3 women; age, 42+/-9 y; range, 26-57 y) with transfemoral amputation. Research participants were long-term users of a mechanical prosthesis (20+/-10 y as an amputee; range, 3-36 y). They were fitted with a microprocessor-controlled knee prosthesis and allowed to acclimate (mean time, 18+/-8 wk) before being retested. Objective measurements of energy efficiency and total daily energy expenditure were obtained. The Prosthetic Evaluation Questionnaire was used to gather subjective feedback from the participants. Subjects demonstrated significantly increased physical activity-related energy expenditure levels in the participant's free-living environment (P=.04) after wearing the microprocessor-controlled prosthetic knee joint. There was no significant difference in the energy efficiency of walking (P=.34). When using the microprocessor-controlled knee, the subjects expressed increased satisfaction in their daily lives (P=.02). People ambulating with a microprocessor-controlled knee significantly increased their physical activity during daily life, outside the laboratory setting, and expressed an increased quality of life.

Increasing Flexibility in Energy Code Compliance: Performance Packages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hart, Philip R.; Rosenberg, Michael I.

Energy codes and standards have provided significant increases in building efficiency over the last 38 years, since the first national energy code was published in late 1975. The most commonly used path in energy codes, the prescriptive path, appears to be reaching a point of diminishing returns. As the code matures, the prescriptive path becomes more complicated, and also more restrictive. It is likely that an approach that considers the building as an integrated system will be necessary to achieve the next real gains in building efficiency. Performance code paths are increasing in popularity; however, there remains a significant designmore » team overhead in following the performance path, especially for smaller buildings. This paper focuses on development of one alternative format, prescriptive packages. A method to develop building-specific prescriptive packages is reviewed based on a multiple runs of prototypical building models that are used to develop parametric decision analysis to determines a set of packages with equivalent energy performance. The approach is designed to be cost-effective and flexible for the design team while achieving a desired level of energy efficiency performance. A demonstration of the approach based on mid-sized office buildings with two HVAC system types is shown along with a discussion of potential applicability in the energy code process.« less

An ultra-high gain and efficient amplifier based on Raman amplification in plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vieux, G.; Cipiccia, S.; Grant, D. W.

Raman amplification arising from the excitation of a density echelon in plasma could lead to amplifiers that significantly exceed current power limits of conventional laser media. Here we show that 1–100 J pump pulses can amplify picojoule seed pulses to nearly joule level. The extremely high gain also leads to significant amplification of backscattered radiation from “noise”, arising from stochastic plasma fluctuations that competes with externally injected seed pulses, which are amplified to similar levels at the highest pump energies. The pump energy is scattered into the seed at an oblique angle with 14 J sr -1, and net gainsmore » of more than eight orders of magnitude. The maximum gain coefficient, of 180 cm -1, exceeds high-power solid-state amplifying media by orders of magnitude. The observation of a minimum of 640 J sr -1 directly backscattered from noise, corresponding to ≈10% of the pump energy in the observation solid angle, implies potential overall efficiencies greater than 10%.« less

An ultra-high gain and efficient amplifier based on Raman amplification in plasma

DOE PAGES

Vieux, G.; Cipiccia, S.; Grant, D. W.; ...

2017-05-25

Raman amplification arising from the excitation of a density echelon in plasma could lead to amplifiers that significantly exceed current power limits of conventional laser media. Here we show that 1–100 J pump pulses can amplify picojoule seed pulses to nearly joule level. The extremely high gain also leads to significant amplification of backscattered radiation from “noise”, arising from stochastic plasma fluctuations that competes with externally injected seed pulses, which are amplified to similar levels at the highest pump energies. The pump energy is scattered into the seed at an oblique angle with 14 J sr -1, and net gainsmore » of more than eight orders of magnitude. The maximum gain coefficient, of 180 cm -1, exceeds high-power solid-state amplifying media by orders of magnitude. The observation of a minimum of 640 J sr -1 directly backscattered from noise, corresponding to ≈10% of the pump energy in the observation solid angle, implies potential overall efficiencies greater than 10%.« less

Behavior-aware cache hierarchy optimization for low-power multi-core embedded systems

NASA Astrophysics Data System (ADS)

Zhao, Huatao; Luo, Xiao; Zhu, Chen; Watanabe, Takahiro; Zhu, Tianbo

2017-07-01

In modern embedded systems, the increasing number of cores requires efficient cache hierarchies to ensure data throughput, but such cache hierarchies are restricted by their tumid size and interference accesses which leads to both performance degradation and wasted energy. In this paper, we firstly propose a behavior-aware cache hierarchy (BACH) which can optimally allocate the multi-level cache resources to many cores and highly improved the efficiency of cache hierarchy, resulting in low energy consumption. The BACH takes full advantage of the explored application behaviors and runtime cache resource demands as the cache allocation bases, so that we can optimally configure the cache hierarchy to meet the runtime demand. The BACH was implemented on the GEM5 simulator. The experimental results show that energy consumption of a three-level cache hierarchy can be saved from 5.29% up to 27.94% compared with other key approaches while the performance of the multi-core system even has a slight improvement counting in hardware overhead.

Defects with deep levels in a semiconductor structure of a photoelectric converter of solar energy with an antireflection film of porous silicon

NASA Astrophysics Data System (ADS)

Tregulov, V. V.; Litvinov, V. G.; Ermachikhin, A. V.

2017-11-01

Defects in a semiconductor structure of a photoelectric converter of solar energy based on a p-n junction with an antireflection film of porous silicon on the front surface have been studied by current deeplevel transient spectroscopy. An explanation of the influence of thickness of a porous-silicon film formed by electrochemical etching on the character of transformation of defects with deep levels and efficiency of solarenergy conversion is proposed.

Experimental thermodynamics of single molecular motor.

PubMed

Toyabe, Shoichi; Muneyuki, Eiro

2013-01-01

Molecular motor is a nano-sized chemical engine that converts chemical free energy to mechanical motions. Hence, the energetics is as important as kinetics in order to understand its operation principle. We review experiments to evaluate the thermodynamic properties of a rotational F1-ATPase motor (F1-motor) at a single-molecule level. We show that the F1-motor achieves 100% thermo dynamic efficiency at the stalled state. Furthermore, the motor reduces the internal irreversible heat inside the motor to almost zero and achieves a highly-efficient free energy transduction close to 100% during rotations far from quasistatic process. We discuss the mechanism of how the F1-motor achieves such a high efficiency, which highlights the remarkable property of the nano-sized engine F1-motor.

Quantum-Carnot engine for particle confined to cubic potential

NASA Astrophysics Data System (ADS)

Sutantyo, Trengginas Eka P.; Belfaqih, Idrus H.; Prayitno, T. B.

2015-09-01

Carnot cycle consists of isothermal and adiabatic processes which are reversible. Using analogy in quantum mechanics, these processes can be well explained by replacing variables in classical process with a quantum system. Quantum system which is shown in this paper is a particle that moves under the influence of a cubic potential which is restricted only to the state of the two energy levels. At the end, the efficiency of the system is shown as a function of the width ratio between the initial conditions and the farthest wall while expanding. Furthermore, the system efficiency will be considered 1D and 2D cases. The providing efficiencies are different due to the influence of the degeneration of energy and the degrees of freedom of the system.

Performance Evaluation and Comparative Analysis of SubCarrier Modulation Wake-up Radio Systems for Energy-Efficient Wireless Sensor Networks

PubMed Central

Oller, Joaquim; Demirkol, Ilker; Casademont, Jordi; Paradells, Josep; Gamm, Gerd Ulrich; Reindl, Leonhard

2014-01-01

Energy-efficient communication is one of the main concerns of wireless sensor networks nowadays. A commonly employed approach for achieving energy efficiency has been the use of duty-cycled operation of the radio, where the node's transceiver is turned off and on regularly, listening to the radio channel for possible incoming communication during its on-state. Nonetheless, such a paradigm performs poorly for scenarios of low or bursty traffic because of unnecessary activations of the radio transceiver. As an alternative technology, Wake-up Radio (WuR) systems present a promising energy-efficient network operation, where target devices are only activated in an on-demand fashion by means of a special radio signal and a WuR receiver. In this paper, we analyze a novel wake-up radio approach that integrates both data communication and wake-up functionalities into one platform, providing a reconfigurable radio operation. Through physical experiments, we characterize the delay, current consumption and overall operational range performance of this approach under different transmit power levels. We also present an actual single-hop WuR application scenario, as well as demonstrate the first true multi-hop capabilities of a WuR platform and simulate its performance in a multi-hop scenario. Finally, by thorough qualitative comparisons to the most relevant WuR proposals in the literature, we state that the proposed WuR system stands out as a strong candidate for any application requiring energy-efficient wireless sensor node communications. PMID:24451452

Performance evaluation and comparative analysis of SubCarrier Modulation Wake-up Radio systems for energy-efficient wireless sensor networks.

PubMed

Oller, Joaquim; Demirkol, Ilker; Casademont, Jordi; Paradells, Josep; Gamm, Gerd Ulrich; Reindl, Leonhard

2013-12-19

Energy-efficient communication is one of the main concerns of wireless sensor networks nowadays. A commonly employed approach for achieving energy efficiency has been the use of duty-cycled operation of the radio, where the node's transceiver is turned off and on regularly, listening to the radio channel for possible incoming communication during its on-state. Nonetheless, such a paradigm performs poorly for scenarios of low or bursty traffic because of unnecessary activations of the radio transceiver. As an alternative technology, Wake-up Radio (WuR) systems present a promising energy-efficient network operation, where target devices are only activated in an on-demand fashion by means of a special radio signal and a WuR receiver. In this paper, we analyze a novel wake-up radio approach that integrates both data communication and wake-up functionalities into one platform, providing a reconfigurable radio operation. Through physical experiments, we characterize the delay, current consumption and overall operational range performance of this approach under different transmit power levels. We also present an actual single-hop WuR application scenario, as well as demonstrate the first true multi-hop capabilities of a WuR platform and simulate its performance in a multi-hop scenario. Finally, by thorough qualitative comparisons to the most relevant WuR proposals in the literature, we state that the proposed WuR system stands out as a strong candidate for any application requiring energy-efficient wireless sensor node communications.

The Impact of DOE Building Technology Energy Efficiency Programs on U.S. Employment, Income, and Investment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Michael J.; Roop, Joseph M.; Schultz, Robert W.

2008-07-31

To more fully evaluate its programs to increase the energy efficiency of the U.S. residential and commercial building stock, the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) assesses the macroeconomic impacts of those programs, specifically on national employment, wage income, and (most recently) investment. The analysis is conducted using the Impact of Sector Energy Technologies (ImSET) model, a special-purpose 188-sector input-output model of the U.S. economy designed specifically to evaluate the impacts of energy efficiency investments and saving. For the analysis described in the paper, ImSET was amended to provide estimates of sector-by-sector capital requirementsmore » and investment. In the scenario of the Fiscal Year (FY) 2005 Buildings Technology (BT) program, the technologies and building practices being developed and promoted by the BT program have the prospect of saving about 2.9×1015 Btu in buildings by the year 2030, about 27% of the expected growth in buildings energy consumption by the year 2030. The analysis reported in the paper finds that, by the year 2030, these savings have the potential to increase employment by up to 446,000 jobs, increase wage income by $7.8 billion, reduce needs for capital stock in the energy sector and closely related supporting industries by about $207 billion (and the corresponding annual level of investment by $13 billion), and create net capital savings that are available to grow the nation’s future economy.« less

Identifying risk factors for exposure to culturable allergenic moulds in energy efficient homes by using highly specific monoclonal antibodies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharpe, Richard A.; Cocq, Kate Le; Nikolaou, Vasilis

The aim of this study was to determine the accuracy of monoclonal antibodies (mAbs) in identifying culturable allergenic fungi present in visible mould growth in energy efficient homes, and to identify risk factors for exposure to these known allergenic fungi. Swabs were taken from fungal contaminated surfaces and culturable yeasts and moulds isolated by using mycological culture. Soluble antigens from cultures were tested by ELISA using mAbs specific to the culturable allergenic fungi Aspergillus and Penicillium spp., Ulocladium, Alternaria, and Epicoccum spp., Cladosporium spp., Fusarium spp., and Trichoderma spp. Diagnostic accuracies of the ELISA tests were determined by sequencing ofmore » the internally transcribed spacer 1 (ITS1)-5.8S-ITS2-encoding regions of recovered fungi following ELISA. There was 100% concordance between the two methods, with ELISAs providing genus-level identity and ITS sequencing providing species-level identities (210 out of 210 tested). Species of Aspergillus/Penicillium, Cladosporium, Ulocladium/Alternaria/Epicoccum, Fusarium and Trichoderma were detected in 82% of the samples. The presence of condensation was associated with an increased risk of surfaces being contaminated by Aspergillus/Penicillium spp. and Cladosporium spp., whereas moisture within the building fabric (water ingress/rising damp) was only associated with increased risk of Aspergillus/Penicillium spp. Property type and energy efficiency levels were found to moderate the risk of indoor surfaces becoming contaminated with Aspergillus/Penicillium and Cladosporium which in turn was modified by the presence of condensation, water ingress and rising damp, consistent with previous literature. - Highlights: • Monoclonal antibodies were used to track culturable allergenic moulds in homes. • Allergenic moulds were recovered from 82% of swabs from contaminated surfaces. • The mAbs were highly specific with 100% agreement to PCR of recovered fungi. • Improvements to energy efficiency lowered risk of exposure to allergenic fungi.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

The technology necessary to build net zero energy buildings (NZEBs) is ready and available today, however, building to net zero energy performance levels can be challenging. Energy efficiency measures, onsite energy generation resources, load matching and grid interaction, climatic factors, and local policies vary from location to location and require unique methods of constructing NZEBs. It is recommended that Components start looking into how to construct and operate NZEBs now as there is a learning curve to net zero construction and FY 2020 is just around the corner.

Learning energy literacy concepts from energy-efficient homes

NASA Astrophysics Data System (ADS)

Paige, Frederick Eugene

The purpose of this study is to understand ways that occupants' and visitors' interaction with energy efficient home design affects Energy Literacy. Using a case study approach including interviews, surveys, and observations, I examined the potential for affordable energy efficient homes in the Greenville South Carolina area to "teach" concepts from an Energy Literacy framework developed by dozens of educational partners and federal agencies that comprise the U.S. Global Change Research Program Partners. I paid particular attention to concepts from the framework that are transferable to energy decisions beyond a home's walls. My research reveals ways that interaction with high efficiency homes can effect understanding of the following Energy Literacy concepts: human use of energy is subject to limits and constraints, conservation is one way to manage energy resources, electricity is generated in multiple ways, social and technological innovations effect the amount of energy used by society, and energy use can be calculated and monitored. Examples from my case studies show how the at-home examples can make lessons on energy more personally relevant, easy to understand, and applicable. Specifically, I found that: • Home occupants learn the limits of energy in relation to the concrete and constricting costs associated with their consumption. • Heating and cooling techniques showcase the limits and constraints on different sources of energy. • Relatable systems make it easier to understand energy's limits and constraints. • Indistinct and distant power utilities allow consumers to overlook the root of electricity sources. • Visible examples of electricity generation systems make it clear that electricity is generated in multiple ways. • Small and interactive may mean inefficient electricity generation, but efficient energy education. • Perceptions of expense and complexity create a disconnect between residential energy consumers and renewable electricity generation. • Utility bill limits and constraints exemplify the ability to conserve energy resources. • Replicable examples teach lessons on conservation. • Via an understanding of the water-energy nexus, water conservation lessons transfer to energy saving lessons. • Passive design exemplifies how a shift in thinking can conserve energy resources through informed efficient decision-making. • Societal shifts in energy consumption are evident at home. • Efficient homes provide applicable examples of social and technological innovations. • The home is the environment in which memorable lessons on energy are passed through cultures. • Home energy consumption comparisons are a popular and effective social innovation, but people have mixed emotions about their usefulness. • A utility bill communicates that utility companies are monitoring energy use to calculate cost. • Interactivity enhances feedback from energy monitors. • Calculating and monitoring energy use is perceived as a complex mathematical process. • Energy consumption feedback at the appliance level is desired to inform decisions. • There is a separation between personal energy monitoring and public monitoring. Implications of this research are that an energy literate society will have the knowledge that is a prerequisite for the motivation to address energy and climate issues. Educators, policy makers, engineers, and designers all play a role in creating a built environment that encourages energy saving behavior.

Power inversion design for ocean wave energy harvesting

NASA Astrophysics Data System (ADS)

Talebani, Anwar N.

The needs for energy sources are increasing day by day because of several factors, such as oil depletion, and global climate change due to the higher level of CO2, so the exploration of various renewable energy sources is very promising area of study. The available ocean waves can be utilized as free source of energy as the water covers 70% of the earth surface. This thesis presents the ocean wave energy as a source of renewable energy. By addressing the problem of designing efficient power electronics system to deliver 5 KW from the induction generator to the grid with less possible losses and harmonics as possible and to control current fed to the grid to successfully harvest ocean wave energy. We design an AC-DC full bridge rectifier converter, and a DC-DC boost converter to harvest wave energy from AC to regulated DC. In order to increase the design efficiency, we need to increase the power factor from (0.5-0.6) to 1. This is accomplished by designing the boost converter with power factor correction in continues mode with RC circuit as an input to the boost converter power factor correction. This design results in a phase shift between the input current and voltage of the full bridge rectifier to generate a small reactive power. The reactive power is injected to the induction generator to maintain its functionality by generating a magnetic field in its stator. Next, we design a single-phase pulse width modulator full bridge voltage source DC-AC grid-tied mode inverter to harvest regulated DC wave energy to AC. The designed inverter is modulated by inner current loop, to control current injected to the grid with minimal filter component to maintain power quality at the grid. The simulation results show that our design successfully control the current level fed to the grid. It is noteworthy that the simulated efficiency is higher than the calculated one since we used an ideal switch in the simulated circuit.

75 FR 34657 - Energy Efficiency and Sustainable Design Standards for New Federal Buildings

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-18

... Efficiency and Sustainable Design Standards for New Federal Buildings AGENCY: Office of Energy Efficiency and....S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Federal Energy Management... June 11, 2010. Cathy Zoi, Assistant Secretary, Energy Efficiency and Renewable Energy. [FR Doc. 2010...

48 CFR 23.203 - Energy-efficient products.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Energy-efficient products... SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy and Water Efficiency and Renewable Energy 23.203 Energy-efficient...

48 CFR 23.203 - Energy-efficient products.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Energy-efficient products... SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy and Water Efficiency and Renewable Energy 23.203 Energy-efficient...

48 CFR 23.203 - Energy-efficient products.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Energy-efficient products... SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy and Water Efficiency and Renewable Energy 23.203 Energy-efficient...

48 CFR 23.203 - Energy-efficient products.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Energy-efficient products... SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy and Water Efficiency and Renewable Energy 23.203 Energy-efficient...

48 CFR 23.203 - Energy-efficient products.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Energy-efficient products... SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy and Water Efficiency and Renewable Energy 23.203 Energy-efficient...

Energy Efficient Engine: Combustor component performance program

NASA Technical Reports Server (NTRS)

Dubiel, D. J.

1986-01-01

The results of the Combustor Component Performance analysis as developed under the Energy Efficient Engine (EEE) program are presented. This study was conducted to demonstrate the aerothermal and environmental goals established for the EEE program and to identify areas where refinements might be made to meet future combustor requirements. In this study, a full annular combustor test rig was used to establish emission levels and combustor performance for comparison with those indicated by the supporting technology program. In addition, a combustor sector test rig was employed to examine differences in emissions and liner temperatures obtained during the full annular performance and supporting technology tests.

Exploring Valleys without Climbing Every Peak: More Efficient and Forgiving Metabasin Metadynamics via Robust On-the-Fly Bias Domain Restriction

PubMed Central

2015-01-01

Metadynamics is an enhanced sampling method designed to flatten free energy surfaces uniformly. However, the highest-energy regions are often irrelevant to study and dangerous to explore because systems often change irreversibly in unforeseen ways in response to driving forces in these regions, spoiling the sampling. Introducing an on-the-fly domain restriction allows metadynamics to flatten only up to a specified energy level and no further, improving efficiency and safety while decreasing the pressure on practitioners to design collective variables that are robust to otherwise irrelevant high energy driving. This paper describes a new method that achieves this using sequential on-the-fly estimation of energy wells and redefinition of the metadynamics hill shape, termed metabasin metadynamics. The energy level may be defined a priori or relative to unknown barrier energies estimated on-the-fly. Altering only the hill ensures that the method is compatible with many other advances in metadynamics methodology. The hill shape has a natural interpretation in terms of multiscale dynamics, and the computational overhead in simulation is minimal when studying systems of any reasonable size, for instance proteins or other macromolecules. Three example applications show that the formula is accurate and robust to complex dynamics, making metadynamics significantly more forgiving with respect to CV quality and thus more feasible to apply to the most challenging biomolecular systems. PMID:26587809

Enhancement of quasi-static strain energy harvesters using non-uniform cross-section post-buckled beams

NASA Astrophysics Data System (ADS)

Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

2017-08-01

Thanks to their efficiency enhancement systems based on post-buckled structural elements have been extensively used in many applications such as actuation, remote sensing and energy harvesting. The post-buckling snap-through behavior of bilaterally constrained beams has been exploited to create sensing or energy harvesting mechanisms for quasi-static applications. The conversion mechanism has been used to transform low-rate and low-frequency excitations into high-rate motions. Electric energy has been generated from such high-rate motions using piezoelectric transducers. However, lack of control over the post-buckling behavior severely limits the mechanism’s efficiency. This study aims to maximize the levels of harvestable power by controlling the location of snap-throughs along the beam at different buckling transitions. Since the snap-through location cannot be controlled by tuning the geometric properties of a uniform beam, non-uniform cross-sections are examined. An energy-based theoretical model is herein developed to predict the post-buckling response of non-prismatic beams. The total potential energy is minimized under constraints that represent the physical confinement of the beam between the lateral boundaries. The experimentally validated results show that changing the shape and geometric dimensions of non-uniform beams allows for the accurate controlling of the snap-through location at different buckling transitions. A 78.59% improvement in harvested energy levels has been achieved by optimization of beam shape.

Reducing cement's CO2 footprint

USGS Publications Warehouse

van Oss, Hendrik G.

2011-01-01

The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

Colin A. McMillan | NREL

Science.gov Websites

Colin A. McMillan Photo of Colin A. McMillan. Colin McMillan Researcher IV-Operations Research Econometrics Research Interests Systems-level energy efficiency analysis Material and energy flows in economies ; Journal of Industrial Ecology 17, no. 5 (October 2013): 700-11. doi:10.1111/jiec.12050 McMillan, C.A., S.J

The impact of state energy programs and other contextual factors on U.S. buildings energy consumption

NASA Astrophysics Data System (ADS)

Ofori-Boadu, Andrea N. Y. A.

High energy consumption in the United States has been influenced by populations, climates, income and other contextual factors. In the past decades, U.S. energy policies have pursued energy efficiency as a national strategy for reducing U.S. environmental degradation and dependence on foreign oils. The quest for improved energy efficiency has led to the development of energy efficient technologies and programs. The implementation of energy programs in the complex U.S. socio-technical environment is believed to promote the diffusion of energy efficiency technologies. However, opponents doubt the fact that these programs have the capacity to significantly reduce U.S. energy consumption. In order to contribute to the ongoing discussion, this quantitative study investigated the relationships existing among electricity consumption/ intensity, energy programs and contextual factors in the U.S. buildings sector. Specifically, this study sought to identify the significant predictors of electricity consumption and intensity, as well as estimate the overall impact of selected energy programs on electricity consumption and intensity. Using state-level secondary data for 51 U.S. states from 2006 to 2009, seven random effects panel data regression models confirmed the existence of significant relationships among some energy programs, contextual factors, and electricity consumption/intensity. The most significant predictors of improved electricity efficiency included the price of electricity, public benefits funds program, building energy codes program, financial and informational incentives program and the Leadership in Energy and Environmental Design (LEED) program. Consistently, the Southern region of the U.S. was associated with high electricity consumption and intensity; while the U.S. commercial sector was the greater benefactor from energy programs. On the average, energy programs were responsible for approximately 7% of the variation observed in electricity consumption and intensity, over and above the variation associated with the contextual factors. This study also had implications in program implementation theory, and revealed that resource availability, stringency and adherence had significant impacts on program outcomes. Using seven classification tables, this study categorized and matched the predictors of electricity consumption and intensity with the specific energy sectors in which they demonstrated significance. Project developers, energy advocates, policy makers, program administrators, building occupants and other stakeholders could use study findings in conjunction with other empirical findings, to make informed decisions regarding the adoption, continuation or discontinuation of energy programs, while taking contextual factors into consideration. The adoption and efficient implementation of the most significant programs could reduce U.S. electricity consumption, and in the long term, probably reduce U.S. energy waste, environmental degradation, energy imports, energy prices, and demands for expanding energy generation and distribution infrastructure.

The regulation of the chloroplast proton motive force plays a key role for photosynthesis in fluctuating light.

PubMed

Armbruster, Ute; Correa Galvis, Viviana; Kunz, Hans-Henning; Strand, Deserah D

2017-06-01

Plants use sunlight as their primary energy source. During photosynthesis, absorbed light energy generates reducing power by driving electron transfer reactions. These are coupled to the transfer of protons into the thylakoid lumen, generating a proton motive force (pmf) required for ATP synthesis. Sudden alterations in light availability have to be met by regulatory mechanisms to avoid the over-accumulation of reactive intermediates and maximize energy efficiency. Here, the acidification of the lumen, as an intermediate product of photosynthesis, plays an important role by regulating photosynthesis in response to excitation energy levels. Recent findings reveal pmf regulation and the modulation of its composition as key determinants for efficient photosynthesis, plant growth, and survival in fluctuating light environments. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Final report to the Department of Energy: Green Schools Project DE-FC01-99EE10685. Schools for the 21st century: Transferring the Green Schools experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrigan, Merrilee

2002-01-15

This report describes five major activities that the Alliance to Save Energy performed for the years 2000 and 2001 to support and compliment DOE's Energy Smart Schools Partnership. The major tasks under this project were to: (1) Promote the School Efficiency Peer Exchange program for school personnel; (2) develop the Earth Apple Awards program and disseminate the best award-winning ideas; (3) link Green Schools with Rebuilt with at least one metropolitan area such as Philadelphia or Buffalo; (4) support Rebuild/Energy Smart Schools through working at the state level to develop business, state, and local government and through making presentations inmore » support of school efficiency; (5) update the curriculum search originally conducted in 1995.« less

Driving Demand for Home Energy Improvements: Motivating residential customers to invest in comprehensive upgrades that eliminate energy waste, avoid high utility bills, and spur the economy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuller, Merrian C.

Policy makers and program designers in the U.S. and abroad are deeply concerned with the question of how to scale up energy efficiency to a level that is commensurate both to the scale of the energy and climate challenges we face, and to the potential for energy savings that has been touted for decades. When policy makers ask what energy efficiency can do, the answers usually revolve around the technical and economic potential of energy efficiency - they rarely hone in on the element of energy demand that matters most for changing energy usage in existing homes: the consumer. Amore » growing literature is concerned with the behavioral underpinnings of energy consumption. We examine a narrower, related subject: How can millions of Americans be persuaded to divert valued time and resources into upgrading their homes to eliminate energy waste, avoid high utility bills, and spur the economy? With hundreds of millions of public dollars flowing into incentives, workforce training, and other initiatives to support comprehensive home energy improvements, it makes sense to review the history of these programs and begin gleaning best practices for encouraging comprehensive home energy improvements. Looking across 30 years of energy efficiency programs that targeted the residential market, many of the same issues that confronted past program administrators are relevant today: How do we cost-effectively motivate customers to take action? Who can we partner with to increase program participation? How do we get residential efficiency programs to scale? While there is no proven formula - and only limited success to date with reliably motivating large numbers of Americans to invest in comprehensive home energy improvements, especially if they are being asked to pay for a majority of the improvement costs - there is a rich and varied history of experiences that new programs can draw upon. Our primary audiences are policy makers and program designers - especially those that are relatively new to the field, such as the over 2,000 towns, cities, states, and regions who are recipients of American Reinvestment and Recovery Act funds for clean energy programs. This report synthesizes lessons from first generation programs, highlights emerging best practices, and suggests methods and approaches to use in designing, implementing, and evaluating these programs. We examined 14 residential energy efficiency programs, conducted an extensive literature review, interviewed industry experts, and surveyed residential contractors to draw out these lessons.« less

Cost-Benefit of Improving the Efficiency of Room Air Conditioners (Inverter and Fixed Speed) in India

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phadke, Amol; Shah, Nihar; Abhyankar, Nikit

Improving efficiency of air conditioners (ACs) typically involves improving the efficiency of various components such as compressors, heat exchangers, expansion valves, refrigerant,and fans. We estimate the incremental cost of improving the efficiency of room ACs based on the cost of improving the efficiency of its key components. Further, we estimate the retail price increase required to cover the cost of efficiency improvement, compare it with electricity bill savings, and calculate the payback period for consumers to recover the additional price of a more efficient AC. The finding that significant efficiency improvement is cost effective from a consumer perspective is robustmore » over a wide range of assumptions. If we assume a 50% higher incremental price compared to our baseline estimate, the payback period for the efficiency level of 3.5 ISEER is 1.1 years. Given the findings of this study, establishing more stringent minimum efficiency performance criteria (one-star level) should be evaluated rigorously considering significant benefits to consumers, energy security, and environment« less

Three strategies for conservation

NASA Technical Reports Server (NTRS)

1975-01-01

The three strategies considered as energy conservation oriented were given: national energy conservation, electrification, and diversification. The first one applies to the near term period (now-1985), the second one to the mid term (1985-2000), and the third one to the far term (2000- ). The rest of this section was focussed on the near term period. The following proposed actions were considered: (1) roll back the price of newly discovered oil, (2) force conversion of many power plants from gas and oil to coal, (3) freeze gasoline production for three years at 1972 levels, (4) mandate automobile mileage requirements, (5) require industry to improve energy efficiency, and (6) require manufacture of household appliances with greater efficiency. Each of these six actions was described and discussed in more detail.

An inductor-based converter with EMI reduction for low-voltage thermoelectric energy harvesting

NASA Astrophysics Data System (ADS)

Wang, Chuang; Zhao, Kai; Li, Zunchao

2017-07-01

This paper presents a self-powered inductor-based converter which harvests thermoelectric energy and boosts extremely low voltage to a typical voltage level for supplying body sensor nodes. Electromagnetic interference (EMI) of the converter is reduced by spreading spectrum of fundamental frequency and harmonics via pseudo-random modulation, which is obtained via combining the linear feedback shift register and digitally controlled oscillator. Besides, the methods, namely extracting energy near MPP and reducing the power dissipation, are employed to improve the power efficiency. The presented inductor-based converter is designed and verified in CSMC CMOS 0.18-µm 1P6M process. The results reveal that it achieves the high efficiency and EMI reduction at the same time.

12 J, 10 Hz diode-pumped Nd:YAG distributed active mirror amplifier chain with ASE suppression.

PubMed

Liu, Tinghao; Sui, Zhan; Chen, Lin; Li, Zhupeng; Liu, Qiang; Gong, Mali; Fu, Xing

2017-09-04

Experimental amplification of 10-ns pulses to an energy of 12.2 J at the repetition rate of 1-10 Hz is reported from a diode-pumped room-temperature distributed active mirror amplifier chain (DAMAC) based on Nd:YAG slabs. Efficient power scaling at the optical-optical efficiency of 20.6% was achieved by suppressing the transverse parasitic oscillation with ASE absorbers. To the best of our knowledge, this is the first demonstration of a diode-pumped Nd:YAG active-mirror laser with nanosecond pulse energy beyond 10 joules. The verified DAMAC concept holds the promise of scaling the energy to a 50 J level and higher by adding 10-12 more pieces of active mirror in the chain.

Comparison of Test Procedures and Energy Efficiency Criteria in Selected International Standards and Labeling Programs for Clothes Washers, Water Dispensers, Vending Machines and CFLs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fridley, David; Zheng, Nina; Zhou, Nan

Since the late 1970s, energy labeling programs and mandatory energy performance standards have been used in many different countries to improve the efficiency levels of major residential and commercial equipment. As more countries and regions launch programs covering a greater range of products that are traded worldwide, greater attention has been given to harmonizing the specific efficiency criteria in these programs and the test methods for measurements. For example, an international compact fluorescent light (CFL) harmonization initiative was launched in 2006 to focus on collaboration between Australia, China, Europe and North America. Given the long history of standards and labelingmore » programs, most major energy-consuming residential appliances and commercial equipment are already covered under minimum energy performance standards (MEPS) and/or energy labels. For these products, such as clothes washers and CFLs, harmonization may still be possible when national MEPS or labeling thresholds are revised. Greater opportunity for harmonization exists in newer energy-consuming products that are not commonly regulated but are under consideration for new standards and labeling programs. This may include commercial products such as water dispensers and vending machines, which are only covered by MEPS or energy labels in a few countries or regions. As China continues to expand its appliance standards and labeling programs and revise existing standards and labels, it is important to learn from recent international experiences with efficiency criteria and test procedures for the same products. Specifically, various types of standards and labeling programs already exist in North America, Europe and throughout Asia for products in China's 2010 standards and labeling programs, namely clothes washers, water dispensers, vending machines and CFLs. This report thus examines similarities and critical differences in energy efficiency values, test procedure specifications and other technical performance requirements in existing international programs in order to shed light on where Chinese programs currently stands and considerations for their 2010 programs.« less

Recombination activity associated with thermal donor generation in monocrystalline silicon and effect on the conversion efficiency of heterojunction solar cells

NASA Astrophysics Data System (ADS)

Tomassini, M.; Veirman, J.; Varache, R.; Letty, E.; Dubois, S.; Hu, Y.; Nielsen, Ø.

2016-02-01

The recombination properties of the carrier lifetime-limiting center formed during the generation of oxygen-related thermal donors (so called "old" thermal donors) in n-type Czochralski silicon were determined over a wide range of thermal donors' concentrations. The procedure involved (1) determining the various energy levels associated with dopants with the help of temperature Hall effect measurements, (2) clarifying which energy level limits the carrier lifetime by temperature lifetime spectroscopy, and (3) determining the recombination parameters of the involved defect from room-temperature carrier lifetime curves. Our results support the fact that a deep energy level in the range of 0.2-0.3 eV below the conduction band limits the carrier lifetime. The second family of thermal donors, featuring bistable properties, was tentatively identified as the corresponding defect. From the obtained experimental data, the influence of the defect on the amorphous/crystalline silicon heterojunction solar cell conversion efficiency was simulated. It is observed that for extended donor generation, the carrier lifetime is reduced by orders-of-magnitude, leading to unacceptable losses in photovoltaic conversion efficiency. A key result is that even for samples with thermal donor concentrations of 1015 cm-3—often met in seed portions of commercial ingots—simulations reveal efficiency losses greater than 1% absolute for state-of-the-art cells, in agreement with recent experimental studies from our group. This result indicates to crystal growers the importance to mitigate the formation of thermal donors or to develop cost-effective processes to suppress them at the ingot/wafer scale. This is even more critical as ingot cool-down is likely to be slower for future larger ingots, thus promoting the formation of thermal donors.

10 CFR 431.16 - Test procedures for the measurement of energy efficiency.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Test procedures for the measurement of energy efficiency. 431.16 Section 431.16 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR... Methods of Determining Efficiency § 431.16 Test procedures for the measurement of energy efficiency. For...

10 CFR 431.16 - Test procedures for the measurement of energy efficiency.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Test procedures for the measurement of energy efficiency. 431.16 Section 431.16 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR... Methods of Determining Efficiency § 431.16 Test procedures for the measurement of energy efficiency. For...

Calibration of 4π NaI(Tl) detectors with coincidence summing correction using new numerical procedure and ANGLE4 software

NASA Astrophysics Data System (ADS)

Badawi, Mohamed S.; Jovanovic, Slobodan I.; Thabet, Abouzeid A.; El-Khatib, Ahmed M.; Dlabac, Aleksandar D.; Salem, Bohaysa A.; Gouda, Mona M.; Mihaljevic, Nikola N.; Almugren, Kholud S.; Abbas, Mahmoud I.

2017-03-01

The 4π NaI(Tl) γ-ray detectors are consisted of the well cavity with cylindrical cross section, and the enclosing geometry of measurements with large detection angle. This leads to exceptionally high efficiency level and a significant coincidence summing effect, much more than a single cylindrical or coaxial detector especially in very low activity measurements. In the present work, the detection effective solid angle in addition to both full-energy peak and total efficiencies of well-type detectors, were mainly calculated by the new numerical simulation method (NSM) and ANGLE4 software. To obtain the coincidence summing correction factors through the previously mentioned methods, the simulation of the coincident emission of photons was modeled mathematically, based on the analytical equations and complex integrations over the radioactive volumetric sources including the self-attenuation factor. The measured full-energy peak efficiencies and correction factors were done by using 152Eu, where an exact adjustment is required for the detector efficiency curve, because neglecting the coincidence summing effect can make the results inconsistent with the whole. These phenomena, in general due to the efficiency calibration process and the coincidence summing corrections, appear jointly. The full-energy peak and the total efficiencies from the two methods typically agree with discrepancy 10%. The discrepancy between the simulation, ANGLE4 and measured full-energy peak after corrections for the coincidence summing effect was on the average, while not exceeding 14%. Therefore, this technique can be easily applied in establishing the efficiency calibration curves of well-type detectors.