Science.gov

Sample records for seasonal thermal energy

  1. Seasonal thermal energy storage

    SciTech Connect

    Allen, R.D.; Kannberg, L.D.; Raymond, J.R.

    1984-05-01

    This report describes the following: (1) the US Department of Energy Seasonal Thermal Energy Storage Program, (2) aquifer thermal energy storage technology, (3) alternative STES technology, (4) foreign studies in seasonal thermal energy storage, and (5) economic assessment.

  2. Seasonal Thermal Energy Storage Program

    NASA Technical Reports Server (NTRS)

    Minor, J. E.

    1980-01-01

    The Seasonal Thermal Energy Storage (STES) Program designed to demonstrate the storage and retrieval of energy on a seasonal basis using heat or cold available from waste or other sources during a surplus period is described. Factors considered include reduction of peak period demand and electric utility load problems and establishment of favorable economics for district heating and cooling systems for commercialization of the technology. The initial thrust of the STES Program toward utilization of ground water systems (aquifers) for thermal energy storage is emphasized.

  3. Seasonal Solar Thermal Absorption Energy Storage Development.

    PubMed

    Daguenet-Frick, Xavier; Gantenbein, Paul; Rommel, Mathias; Fumey, Benjamin; Weber, Robert; Gooneseker, Kanishka; Williamson, Tommy

    2015-01-01

    This article describes a thermochemical seasonal storage with emphasis on the development of a reaction zone for an absorption/desorption unit. The heat and mass exchanges are modelled and the design of a suitable reaction zone is explained. A tube bundle concept is retained for the heat and mass exchangers and the units are manufactured and commissioned. Furthermore, experimental results of both absorption and desorption processes are presented and the exchanged power is compared to the results of the simulations.

  4. Bibliography of the seasonal thermal energy storage library

    SciTech Connect

    Prater, L.S.; Casper, G.; Kawin, R.A.

    1981-08-01

    The Main Listing is arranged alphabetically by the last name of the first author. Each citation includes the author's name, title, publisher, publication date, and where applicable, the National Technical Information Service (NTIS) number or other document number. The number preceding each citation is the identification number for that document in the Seasonal Thermal Energy Storage (STES) Library. Occasionally, one or two alphabetic characters are added to the identification number. These alphabetic characters indicate that the document is contained in a collection of papers, such as the proceedings of a conference. An Author Index and an Identification Number Index are included. (WHK)

  5. Aquifer thermal energy storage reference manual: seasonal thermal energy storage program

    SciTech Connect

    Prater, L.S.

    1980-01-01

    This is the reference manual of the Seasonal Thermal Energy Storage (STES) Program, and is the primary document for the transfer of technical information of the STES Program. It has been issued in preliminary form and will be updated periodically to include more technical data and results of research. As the program progresses and new technical data become available, sections of the manual will be revised to incorporate these data. This primary document contains summaries of: the TRW, incorporated demonstration project at Behtel, Alaska, Dames and Moore demonstration project at Stony Brook, New York, and the University of Minnesota demonstration project at Minneapolis-St. Paul, Minnesota; the technical support programs including legal/institutional assessment; economic assessment; environmental assessment; field test facilities; a compendia of existing information; numerical simulation; and non-aquifer STES concepts. (LCL)

  6. Seasonal thermal energy storage program. Progress report, January 1980-December 1980

    SciTech Connect

    Minor, J.E.

    1981-05-01

    The objectives of the Seasonal Thermal Energy Storage (STES) Program is to demonstrate the economic storage and retrieval of energy on a seasonal basis, using heat or cold available from waste sources or other sources during a surplus period to reduce peak period demand, reduce electric utilities peaking problems, and contribute to the establishment of favorable economics for district heating and cooling systems for commercialization of the technology. Aquifers, ponds, earth, and lakes have potential for seasonal storage. The initial thrust of the STES Program is toward utilization of ground-water systems (aquifers) for thermal energy storage. Program plans for meeting these objectives, the development of demonstration programs, and progress in assessing the technical, economic, legal, and environmental impacts of thermal energy storage are described. (LCL)

  7. Preliminary survey and evaluation of nonaquifer thermal energy storage concepts for seasonal storage

    SciTech Connect

    Blahnik, D.E.

    1980-11-01

    Thermal energy storage enables the capture and retention of heat energy (or cold) during one time period for use during another. Seasonal thermal energy storage (STES) involves a period of months between the input and recovery of energy. The purpose of this study was to make a preliminary investigation and evaluation of potential nonaquifer STES systems. Current literature was surveyed to determine the state of the art of thermal energy storage (TES) systems such as hot water pond storage, hot rock storage, cool ice storage, and other more sophisticated concepts which might have potential for future STES programs. The main energy sources for TES principally waste heat, and the main uses of the stored thermal energy, i.e., heating, cooling, and steam generation are described. This report reviews the development of sensible, latent, and thermochemical TES technologies, presents a preliminary evaluation of the TES methods most applicable to seasonal storage uses, outlines preliminary conclusions drawn from the review of current TES literature, and recommends further research based on these conclusions. A bibliography of the nonaquifer STES literature review, and examples of 53 different TES concepts drawn from the literature are provided. (LCL)

  8. Summary of seasonal thermal energy storage field test projects in the United States

    SciTech Connect

    Johnson, B.K.

    1989-07-01

    Seasonal thermal energy storage (STES) involves storage of available heat or chill for distribution at a later time to meet thermal loads. STES can reduce energy consumption, peak energy demand, and emissions of carbon dioxide to the atmosphere over conventional systems. It is estimated that full-scale application of STES would provide 2% to 4% of total energy needs in the United States. One STES technology, aquifer thermal energy storage (ATES), has been determined to be the most cost-effective option in the United States when site conditions enable its use. ATES has been analyzed in the laboratory and investigated in the field in the United States since the program was established at Pacific Northwest Laboratory (PNL) in 1979. Two field test facilities (FTFs), one for heating ATES at the University of Minnesota and the other for cooling ATES at the University of Alabama, have been primary testing grounds for US ATES research. Computer models have been developed to analyze the complex thermal and fluid dynamics. Extensive monitoring of FTFs has provided verification of and refinements to the computer models. The areas of geochemistry and microbiology have been explored as they apply to the aquifer environment. In general, the two FTFs have been successful in demonstrating the steps needed to make an ATES system operational.

  9. Seasonal Thermal Energy Storage Program: Progress summary for the period April 1986 through March 1988

    SciTech Connect

    Kannberg, L.D.

    1988-10-01

    This report discusses recent progress in the DOE program, directed by Pacific Northwest Laboratory, to develop seasonal thermal energy storage (STES). STES has been identified as one method to substantially improve energy efficiency and economics in certain sectors of our economy. It provides a potentially economic means of using waste heat and climatic energy resources to meet a significant portion of our growing energy need for building and industrial process heating and cooling. Environmental benefits accompany the use of STES in many applications. Furthermore, STES can contribute to reduced reliance on premium fuels that are often obtained from foreign sources. Lastly by improving the energy economics of industry, STES can contribute to improved US industrial competitiveness. The report is provided in four sections; the first being this introduction Section 2 of the report describes the program and briefly documents its organization, goals, history, and long-term plans. Section 3 describes the progress during the period from April, 1986, through March, 1988. Section 4 provides a short update on international development of STES. 17 refs., 16 figs., 7 tabs.

  10. Seasonal thermal energy storage in unsaturated soils: Model development and field validation

    SciTech Connect

    Doughty, C.; Nir, Aharon, Tsang, Chin-Fu

    1991-06-01

    This report summarizes ten years of activity carried out at the Earth Sciences Division of the Lawrence Berkeley Laboratory (LBI) in the subject of seasonal storage of thermal energy in unsaturated soils. The objectives of the work were to make a conceptual study of this type of storage, to offer guidelines for planning and evaluation of the method, to produce models and simulation for an actual field experiment, to participate in an on-line data analysis of experimental results. and to evaluate the results in terms of the validation of the concept, models and the experimental techniques. The actual field experiments were performed in Beer-Sheva, Israel. Details of engineering and field operations are not included in this report.

  11. Field and laboratory studies of subsurface water injection: Seasonal Thermal Energy Storage program (STES)

    NASA Astrophysics Data System (ADS)

    Owen, L. B.; Blair, S. C.; Peterson, E.

    1982-12-01

    The Seasonal Thermal Energy Storage (STES) project office at the Battelle, Pacific Northwest Laboratory has sponsored development of an Aquifer Properties Test Facility (APTF) to evaluate the effects of thermal cycling on reservoir properties. The APTF Laboratory apparatus for testing aquifer materials at elevated temperature and pressure (Figure 1) is now being used to evaluate aquifer material from the University of Minnesota Field Test Facility (FTF). Injection well impairment has been experienced at STES sites in Mobile, Alabama and Stony Brook, New York. Terra Tek Research, under contract to Battelle, PNL, performed a laboratory evaluation of impairment mechanisms that may have been involved in the failure of the injection well at the Stony Brook site. Terra Tek Research, again under contract to Battelle, PNL, designed, built and installed a portable Field Injectability Test Stand (FITS) at the STES Field Test Facility, University of Minnesota, St. Paul, Minnesota. The injectability apparatus uses membrane filters and core samples as injection formation analogs to evaluate the response of a representative porous matrix to injected water.

  12. Seasonal meridional energy balance and thermal structure of the atmosphere of Uranus - A radiative-convective-dynamical model

    NASA Technical Reports Server (NTRS)

    Friedson, James; Ingersoll, Andrew P.

    1987-01-01

    A model is presented for the thermodynamics of the seasonal meridional energy balance and thermal structure of the Uranian atmosphere. The model considers radiation and small-scale convection, and dynamical heat fluxes due to large-scale baroclinic eddies. Phase oscillations with a period of 0.5 Uranian year are discerned in the total internal power and global enthalpy storage. The variations in the identity of the main transport agent with the magnitude of the internal heat source are discussed. It is shown that meridional heat transport in the atmosphere is sufficient to lower seasonal horizontal temperature contrasts below those predicted with radiative-convection models.

  13. Liquid temperature determination in a seasonal heat storage at joint operation with a solar collector and thermal energy consumer

    SciTech Connect

    Sivoraksha, V.E.; Zolotko, K.E.; Markov, V.L.; Petrov, B.E.; Lyagushyn, S.F.

    1998-07-01

    Usual solar thermal systems include a solar collector providing solar power conversion into the thermal form and a heat storage accumulating thermal energy, the great capacity of storage systems allows heating and hot water supply during the cold season. The joint operation of the solar collector and a seasonal heat storage has a cyclic mode day by day. The following operation scheme is analyzed in the paper: in night liquid (water) does not circulate; after sunrise the solar collector is warmed up and after its temperature reaching the temperature of water in the thermal energy storage TTS circulation is switched on and thermal power is transferred to the heat storage; after midday water temperature in the solar collector decreases and circulation stops when it becomes equal to the heat storage temperature. TTS increase results in the reduction of the duration of the joint operation of the solar collector and the energy storage and in the decrease of the heat power input. A functional connection between the daily input of power from the solar collector and an average temperature in the heat storage is of importance for technological calculations. The moments of the beginning and end of circulation and daily heat input from the solar collector are determined under the assumption of the sinusoidal law of solar radiation coming in the day-time. Then the heat balance equation is solved for the whole power system with taking into account power consumption and heat losses. The polynomial approximation for the dependence of heat input upon heat carrier temperature permits obtaining an analytical solution for the seasonal behavior of the liquid temperature in the thermal energy storage. The obtained dependence of TTS upon time allows calculation of this parameter with admissible accuracy at the stage of the project development proceeding from the performance of the solar collector and heat storage and from the averaged meteorological data.

  14. Modeling surface energy fluxes and thermal dynamics of a seasonally ice-covered hydroelectric reservoir.

    PubMed

    Wang, Weifeng; Roulet, Nigel T; Strachan, Ian B; Tremblay, Alain

    2016-04-15

    The thermal dynamics of human created northern reservoirs (e.g., water temperatures and ice cover dynamics) influence carbon processing and air-water gas exchange. Here, we developed a process-based one-dimensional model (Snow, Ice, WAater, and Sediment: SIWAS) to simulate a full year's surface energy fluxes and thermal dynamics for a moderately large (>500km(2)) boreal hydroelectric reservoir in northern Quebec, Canada. There is a lack of climate and weather data for most of the Canadian boreal so we designed SIWAS with a minimum of inputs and with a daily time step. The modeled surface energy fluxes were consistent with six years of observations from eddy covariance measurements taken in the middle of the reservoir. The simulated water temperature profiles agreed well with observations from over 100 sites across the reservoir. The model successfully captured the observed annual trend of ice cover timing, although the model overestimated the length of ice cover period (15days). Sensitivity analysis revealed that air temperature significantly affects the ice cover duration, water and sediment temperatures, but that dissolved organic carbon concentrations have little effect on the heat fluxes, and water and sediment temperatures. We conclude that the SIWAS model is capable of simulating surface energy fluxes and thermal dynamics for boreal reservoirs in regions where high temporal resolution climate data are not available. SIWAS is suitable for integration into biogeochemical models for simulating a reservoir's carbon cycle.

  15. Thermal Energy Storage: Fourth Annual Review Meeting

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The development of low cost thermal energy storage technologies is discussed in terms of near term oil savings, solar energy applications, and dispersed energy systems for energy conservation policies. Program definition and assessment and research and technology development are considered along with industrial storage, solar thermal power storage, building heating and cooling, and seasonal thermal storage. A bibliography on seasonal thermal energy storage emphasizing aquifer thermal energy is included.

  16. Aquifer thermal energy storage program

    NASA Technical Reports Server (NTRS)

    Fox, K.

    1980-01-01

    The purpose of the Aquifer Thermal Energy Storage Demonstration Program is to stimulate the interest of industry by demonstrating the feasibility of using a geological formation for seasonal thermal energy storage, thereby, reducing crude oil consumption, minimizing thermal pollution, and significantly reducing utility capital investments required to account for peak power requirements. This purpose will be served if several diverse projects can be operated which will demonstrate the technical, economic, environmental, and institutional feasibility of aquifer thermal energy storage systems.

  17. Model-based assessment of the potential of seasonal aquifer thermal energy storage and recovery as a groundwater ecosystem service for the Brussels-Capital Region

    NASA Astrophysics Data System (ADS)

    Anibas, Christian; Huysmans, Marijke

    2015-04-01

    Urban areas are characterized by their concentrated demand of energy, applying a high pressure on urban ecosystems including atmosphere, soils and groundwater. In the light of global warming, urbanization and an evolving energy system, it is important to know how urbanized areas can contribute to their own energy demands. One option is to use the possibilities aquifers offer as an ecosystem service (BONTE et al., 2011). If used effectively an improvement in air and groundwater quality is achieved. Additionally, the more efficient distribution of the used energy may also lead to a decrease in primary energy consumption (ZUURBIER, 2013). Therefore, investigations of the potential of seasonal aquifer thermal energy storage and recovery (ATES) for the Brussels-Capital Region, Belgium is being conducted. The potential of ATES systems are of special interest for energy demands in high density urban areas because of such infrastructure as office buildings, schools, hospitals and shopping malls. In an open water circuit ATES systems consist of two or more groundwater wells, where in seasonal cycles one subtracts and the other recharges water to the aquifer. Heat pumps use the heat capacity of water for heating or cooling a building. An important limitation of the methodology is the quality of the groundwater used (i.e. precipitation of Fe- or Mn-oxides can decrease the yield). However, ATES systems on the other hand can also improve groundwater quality and groundwater ecosystems. The current knowledge of the potential for ATES systems in the Brussels-Capital Region is based on geological assessments from VITO (2007). The Brussels-Capital Region is divided into a western and eastern section with respect to geology. While the western part has less favorable conditions for ATES, the eastern is composed of the Brussels Sand formation, which is a 20-40 m thick aquifer layer that has the highest potential for ATES systems in the region. By applying groundwater flow and heat

  18. HEATS: Thermal Energy Storage

    SciTech Connect

    2012-01-01

    HEATS Project: The 15 projects that make up ARPA-E’s HEATS program, short for “High Energy Advanced Thermal Storage,” seek to develop revolutionary, cost-effective ways to store thermal energy. HEATS focuses on 3 specific areas: 1) developing high-temperature solar thermal energy storage capable of cost-effectively delivering electricity around the clock and thermal energy storage for nuclear power plants capable of cost-effectively meeting peak demand, 2) creating synthetic fuel efficiently from sunlight by converting sunlight into heat, and 3) using thermal energy storage to improve the driving range of electric vehicles (EVs) and also enable thermal management of internal combustion engine vehicles.

  19. Thermal energy transformer

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M.; Thiele, C. L. (Inventor)

    1979-01-01

    For use in combination with a heat engine, a thermal energy transformer is presented. It is comprised of a flux receiver having a first wall defining therein a radiation absorption cavity for converting solar flux to thermal energy, and a second wall defining an energy transfer wall for the heat engine. There is a heat pipe chamber interposed between the first and second walls having a working fluid disposed within the chamber and a wick lining the chamber for conducting the working fluid from the second wall to the first wall. Thermal energy is transferred from the radiation absorption cavity to the heat engine.

  20. Thermal energy storage

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.; Picklesimer, E. A.

    1978-01-01

    The general scope of study on thermal energy storage development includes: (1) survey and review possible concepts for storing thermal energy; (2) evaluate the potentials of the surveyed concepts for practical applications in the low and high temperature ranges for thermal control and storage, with particular emphasis on the low temperature range, and designate the most promising concepts; and (3) determine the nature of further studies required to expeditiously convert the most promising concept(s) to practical applications. Cryogenic temperature control by means of energy storage materials was also included.

  1. Thermal energy storage

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The planning and implementation of activities associated with lead center management role and the technical accomplishments pertaining to high temperature thermal energy storage subsystems are described. Major elements reported are: (1) program definition and assessment; (2) research and technology development; (3) industrial storage applications; (4) solar thermal power storage applications; and (5) building heating and cooling applications.

  2. The impact of low-temperature seasonal aquifer thermal energy storage (SATES) systems on chlorinated solvent contaminated groundwater: Modeling of spreading and degradation

    NASA Astrophysics Data System (ADS)

    Zuurbier, Koen G.; Hartog, Niels; Valstar, Johan; Post, Vincent E. A.; van Breukelen, Boris M.

    2013-04-01

    Groundwater systems are increasingly used for seasonal aquifer thermal energy storage (SATES) for periodic heating and cooling of buildings. Its use is hampered in contaminated aquifers because of the potential environmental risks associated with the spreading of contaminated groundwater, but positive side effects, such as enhanced contaminant remediation, might also occur. A first reactive transport study is presented to assess the effect of SATES on the fate of chlorinated solvents by means of scenario modeling, with emphasis on the effects of transient SATES pumping and applicable kinetic degradation regime. Temperature effects on physical, chemical, and biological reactions were excluded as calculations and initial simulations showed that the small temperature range commonly involved (ΔT < 15 °C) only caused minor effects. The results show that a significant decrease of the contaminant mass and (eventually) plume volume occurs when degradation is described as sediment-limited with a constant rate in space and time, provided that dense non-aqueous phase liquid (DNAPL) is absent. However, in the presence of DNAPL dissolution, particularly when the dissolved contaminant reaches SATES wells, a considerably larger contaminant plume is created, depending on the balance between DNAPL dissolution and mass removal by degradation. Under conditions where degradation is contaminant-limited and degradation rates depend on contaminant concentrations in the aquifer, a SATES system does not result in enhanced remediation of a contaminant plume. Although field data are lacking and existing regulatory constraints do not yet permit the application of SATES in contaminated aquifers, reactive transport modeling provides a means of assessing the risks of SATES application in contaminated aquifers. The results from this study are considered to be a first step in identifying the subsurface conditions under which SATES can be applied in a safe or even beneficial manner.

  3. Thermal energy storage program description

    SciTech Connect

    Reimers, E.

    1989-03-01

    The U.S. Department of Energy (DOE) has sponsored applied research, development, and demonstration of technologies aimed at reducing energy consumption and encouraging replacement of premium fuels (notably oil) with renewable or abundant indigenous fuels. One of the technologies identified as being able to contribute to these goals is thermal energy storage (TES). Based on the potential for TES to contribute to the historic mission of the DOE and to address emerging energy issues related to the environment, a program to develop specific TES technologies for diurnal, industrial, and seasonal applications is underway. Currently, the program is directed toward three major application targets: (1) TES development for efficient off-peak building heating and cooling, (2) development of advanced TES building materials, and (3) TES development to reduce industrial energy consumption.

  4. Ocean Thermal Energy.

    ERIC Educational Resources Information Center

    Berkovsky, Boris

    1987-01-01

    Describes Ocean Thermal Energy Conservation (OTEC) as a method for exploiting the temperature difference between warm surface waters of the sea and its cold depths. Argues for full-scale demonstrations of the technique for producing energy for coastal regions. (TW)

  5. Ocean thermal energy conversion

    SciTech Connect

    Avery, W.H.

    1983-03-17

    A brief explanation of the Ocean Thermal Energy Conversion (OTEC) concept and an estimate of the amount of energy that can be produced from the ocean resource without introducing environmental concerns are presented. Use of the OTEC system to generate electric power and products which can replace fossil fuels is shown. The OTEC program status and its prospects for the future are discussed.

  6. Thermal energy storage for cogeneration applications

    NASA Astrophysics Data System (ADS)

    Drost, M. K.; Antoniak, Z. I.

    1992-04-01

    Cogeneration is playing an increasingly important role in providing energy efficient power generation and thermal energy for space heating and industrial process heat applications. However, the range of applications for cogeneration could be further increased if the generation of electricity could be decoupled from the generation of process heat. Thermal energy storage (TES) can decouple power generation from the production of process heat, allowing the production of dispatchable power while fully utilizing the thermal energy available from the prime mover. The Pacific Northwest Laboratory (PNL) leads the US Department of Energy's Thermal Energy Storage Program. The program focuses on developing TES for daily cycling (diurnal storage), annual cycling (seasonal storage), and utility applications (utility thermal energy storage (UTES)). Several of these technologies can be used in a cogeneration facility. This paper discusses TES concepts relevant to cogeneration and describes the current status of these TES systems.

  7. Optimum utilization of site energy sources for all-season thermal comfort in new residential construction for single-family attached (rowhouse/townhouse) designs

    SciTech Connect

    Not Available

    1981-02-26

    A proposed design analysis is presented of a passive solar energy efficient system for a typical three-level, three bedroom, two story, garage-under townhouse. The design incorporates the best, most performance-proven and cost effective products, materials, processes, technologies, and sub-systems which are available today. Seven distinct categories recognized for analysis are identified as: the exterior environment; the interior environment; conservation of energy; natural energy utilization; auxiliary energy utilization; control and distribution systems; and occupant adaptation. Preliminary design features, fenestration sysems, the plenum-supply system, the thermal-storage party-fire walls, direct gain storage, the radiant comfort system, and direct passive cooling systems are briefly described. Features of the design under analysis and on which conclusions have not yet been formulated are: the energy reclamation system, auxiliary energy back-up systems, the distribution system and operating modes, the control systems, and non-comfort energy systems and inputs. (MCW)

  8. Thermal energy storage material

    DOEpatents

    Leifer, Leslie

    1976-01-01

    A thermal energy storage material which is stable at atmospheric temperature and pressure and has a melting point higher than 32.degree.F. is prepared by dissolving a specific class of clathrate forming compounds, such as tetra n-propyl or tetra n-butyl ammonium fluoride, in water to form a substantially solid clathrate. The resultant thermal energy storage material is capable of absorbing heat from or releasing heat to a given region as it transforms between solid and liquid states in response to temperature changes in the region above and below its melting point.

  9. Solar thermal energy receiver

    NASA Technical Reports Server (NTRS)

    Baker, Karl W. (Inventor); Dustin, Miles O. (Inventor)

    1992-01-01

    A plurality of heat pipes in a shell receive concentrated solar energy and transfer the energy to a heat activated system. To provide for even distribution of the energy despite uneven impingement of solar energy on the heat pipes, absence of solar energy at times, or failure of one or more of the heat pipes, energy storage means are disposed on the heat pipes which extend through a heat pipe thermal coupling means into the heat activated device. To enhance energy transfer to the heat activated device, the heat pipe coupling cavity means may be provided with extensions into the device. For use with a Stirling engine having passages for working gas, heat transfer members may be positioned to contact the gas and the heat pipes. The shell may be divided into sections by transverse walls. To prevent cavity working fluid from collecting in the extensions, a porous body is positioned in the cavity.

  10. The thermal seasons variability in Poland, 1951-2010

    NASA Astrophysics Data System (ADS)

    Czernecki, Bartosz; Miętus, Mirosław

    2017-01-01

    The aim of this study is to detect variability and changes in the occurrence of the thermal seasons in Poland during the period from 1951 to 2010. A monthly temperature dataset using average area values allowed the researchers to set proper occurrence dates for the thermal seasons' beginnings and length according to the following criteria: winter ( t < 0 °C), early spring (0-5 °C), spring (5-15 °C), summer ( t > 15 °C), autumn (5-15 °C) and early winter (0-5 °C). Statistically significant long-term trends have been detected for the occurrence dates of the thermal seasons' beginnings and season length. Seasonal variability accelerated significantly since the end of the twentieth century. The trend of limiting wintertime in Poland is 0.64 days per year, while summer and early spring seasons are longer by approximately 0.30 and 0.25 days per year, respectively. All seasons since thermal early spring until thermal summer tend to occur earlier, while the following seasons have the opposite trend. As a result, the number of years without thermal winter has substantially increased in the past 20 years. Simultaneously, thermal summer became the longest season in 85 % of years after 1990 in comparison to less than 50 % in the period from 1951 to 1970. Also, the change in the annual course of monthly mean temperature results in the fact that thermal spring is becoming longer than thermal autumn.

  11. Article for thermal energy storage

    DOEpatents

    Salyer, Ival O.

    2000-06-27

    A thermal energy storage composition is provided which is in the form of a gel. The composition includes a phase change material and silica particles, where the phase change material may comprise a linear alkyl hydrocarbon, water/urea, or water. The thermal energy storage composition has a high thermal conductivity, high thermal energy storage, and may be used in a variety of applications such as in thermal shipping containers and gel packs.

  12. Thermal Energy Conversion Branch

    NASA Technical Reports Server (NTRS)

    Bielozer, Matthew C.; Schreiber, Jeffrey, G.; Wilson, Scott D.

    2004-01-01

    The Thermal Energy Conversion Branch (5490) leads the way in designing, conducting, and implementing research for the newest thermal systems used in space applications at the NASA Glenn Research Center. Specifically some of the most advanced technologies developed in this branch can be broken down into four main areas: Dynamic Power Systems, Primary Solar Concentrators, Secondary Solar Concentrators, and Thermal Management. Work was performed in the Dynamic Power Systems area, specifically the Stirling Engine subdivision. Today, the main focus of the 5490 branch is free-piston Stirling cycle converters, Brayton cycle nuclear reactors, and heat rejection systems for long duration mission spacecraft. All space exploring devices need electricity to operate. In most space applications, heat energy from radioisotopes is converted to electrical power. The Radioisotope Thermoelectric Generator (RTG) already supplies electricity for missions such as the Cassini Spacecraft. The focus of today's Stirling research at GRC is aimed at creating an engine that can replace the RTG. The primary appeal of the Stirling engine is its high system efficiency. Because it is so efficient, the Stirling engine will significantly reduce the plutonium fuel mission requirements compared to the RTG. Stirling is also being considered for missions such as the lunar/Mars bases and rovers. This project has focused largely on Stirling Engines of all types, particularly the fluidyne liquid piston engine. The fluidyne was developed by Colin D. West. This engine uses the same concepts found in any type of Stirling engine, with the exception of missing mechanical components. All the working components are fluid. One goal was to develop and demonstrate a working Stirling Fluidyne Engine at the 2nd Annual International Energy Conversion Engineering Conference in Providence, Rhode Island.

  13. Cost effective seasonal storage of wind energy

    SciTech Connect

    Cavallo, A.J.; Keck, M.B.

    1995-09-01

    Seasonal variation of the wind electric potential on the Great Plains could be a significant obstacle to the large scale utilization of wind generated electricity. Wind power densities usually are greatest during the spring, and decrease by at least 30 percent relative to the annual average in many areas during the summer months, when demand is highest. This problem can be overcome by using an oversized wind farm and a compressed air energy storage system (a baseload wind energy system). A minimum volume storage reservoir is needed to transform intermittent wind energy to baseload power, while a larger reservoir can be used to store excess power produced during the spring for either peak power or baseload output during the summer. The yearly average cost of energy increases by about 3 percent for the largest storage reservoir, indicating the seasonal storage of wind energy is economically as well as technically feasible.

  14. Aquifer thermal energy (heat and chill) storage

    SciTech Connect

    Jenne, E.A.

    1992-11-01

    As part of the 1992 Intersociety Conversion Engineering Conference, held in San Diego, California, August 3--7, 1992, the Seasonal Thermal Energy Storage Program coordinated five sessions dealing specifically with aquifer thermal energy storage technologies (ATES). Researchers from Sweden, The Netherlands, Germany, Switzerland, Denmark, Canada, and the United States presented papers on a variety of ATES related topics. With special permission from the Society of Automotive Engineers, host society for the 1992 IECEC, these papers are being republished here as a standalone summary of ATES technology status. Individual papers are indexed separately.

  15. Thermal energy storage test facility

    NASA Technical Reports Server (NTRS)

    Ternes, M. P.

    1980-01-01

    The thermal behavior of prototype thermal energy storage units (TES) in both heating and cooling modes is determined. Improved and advanced storage systems are developed and performance standards are proposed. The design and construction of a thermal cycling facility for determining the thermal behavior of full scale TES units is described. The facility has the capability for testing with both liquid and air heat transport, at variable heat input/extraction rates, over a temperature range of 0 to 280 F.

  16. Ocean Thermal Extractable Energy Visualization

    SciTech Connect

    Ascari, Matthew

    2012-10-28

    The Ocean Thermal Extractable Energy Visualization (OTEEV) project focuses on assessing the Maximum Practicably Extractable Energy (MPEE) from the world’s ocean thermal resources. MPEE is defined as being sustainable and technically feasible, given today’s state-of-the-art ocean energy technology. Under this project the OTEEV team developed a comprehensive Geospatial Information System (GIS) dataset and software tool, and used the tool to provide a meaningful assessment of MPEE from the global and domestic U.S. ocean thermal resources.

  17. Ocean Thermal Energy Conversion (OTEC)

    NASA Technical Reports Server (NTRS)

    Lavi, A.

    1977-01-01

    Energy Research and Development Administration research progress in Ocean Thermal Energy Conversion (OTEC) is outlined. The development program is being focused on cost effective heat exchangers; ammonia is generally used as the heat exchange fluid. Projected costs for energy production by OTEC vary between $1000 to $1700 per kW.

  18. Lih thermal energy storage device

    DOEpatents

    Olszewski, Mitchell; Morris, David G.

    1994-01-01

    A thermal energy storage device for use in a pulsed power supply to store waste heat produced in a high-power burst operation utilizes lithium hydride as the phase change thermal energy storage material. The device includes an outer container encapsulating the lithium hydride and an inner container supporting a hydrogen sorbing sponge material such as activated carbon. The inner container is in communication with the interior of the outer container to receive hydrogen dissociated from the lithium hydride at elevated temperatures.

  19. Thermal energy storage and transport

    NASA Technical Reports Server (NTRS)

    Hausz, W.

    1980-01-01

    The extraction of thermal energy from large LWR and coal fired plants for long distance transport to industrial and residential/commercial users is analyzed. Transport of thermal energy as high temperature water is shown to be considerably cheaper than transport as steam, hot oil, or molten salt over a wide temperature range. The delivered heat is competitive with user-generated heat from oil, coal, or electrode boilers at distances well over 50 km when the pipeline operates at high capacity factor. Results indicate that thermal energy storage makes meeting of even very low capacity factor heat demands economic and feasible and gives the utility flexibility to meet coincident electricity and heat demands effectively.

  20. Predicting tree pollen season start dates using thermal conditions.

    PubMed

    Myszkowska, Dorota

    2014-01-01

    Thermal conditions at the beginning of the year determine the timing of pollen seasons of early flowering trees. The aims of this study were to quantify the relationship between the tree pollen season start dates and the thermal conditions just before the beginning of the season and to construct models predicting the start of the pollen season in a given year. The study was performed in Krakow (Southern Poland); the pollen data of Alnus, Corylus and Betula were obtained in 1991-2012 using a volumetric method. The relationship between the tree pollen season start, calculated by the cumulated pollen grain sum method, and a 5-day running means of maximum (for Alnus and Corylus) and mean (for Betula) daily temperature was found and used in the logistic regression models. The estimation of model parameters indicated their statistically significance for all studied taxa; the odds ratio was higher in models for Betula, comparing to Alnus and Corylus. The proposed model makes the accuracy of prediction in 83.58 % of cases for Alnus, in 84.29 % of cases for Corylus and in 90.41 % of cases for Betula. In years of model verification (2011 and 2012), the season start of Alnus and Corylus was predicted more precisely in 2011, while in case of Betula, the model predictions achieved 100 % of accuracy in both years. The correctness of prediction indicated that the data used for the model arrangement fitted the models well and stressed the high efficacy of model prediction estimated using the pollen data in 1991-2010.

  1. Ocean thermal energy conversion (OTEC)

    SciTech Connect

    Lockerby, R.W.

    1981-01-01

    Ocean thermal energy conversion (OTEC) is reviewed briefly. The two types of OTEC system (open and closed) are described and limitations are pointed out. A bibliography of 148 references on OTEC is given for the time period 1975 to 1980. Entries are arranged alphabetically according to the author's name. (MJJ)

  2. Seasonal Contrasts in the Surface Energy Balance of the Sahel

    SciTech Connect

    Miller, Ron; Slingo, A.; Barnard, James C.; Kassianov, Evgueni I.

    2009-03-14

    Over most of the world ocean, heating of the surface by sunlight is balanced predominately by evaporative cooling. Even over land, moisture for evaporation is available from vegetation or the soil reservoir. However, at the ARM Mobile Facility in Niamey, Niger, soil moisture is so depleted that evaporation makes a significant contribution to the surface energy balance only at the height of the rainy season, when precipitation has replenished the soil reservoir. Using observations at the Mobile Facility from late 2005 to early 2007, we describe how the surface balances radiative forcing. How the surface compensates time-averaged solar heating varies with seasonal changes in atmospheric water vapor, which modulates the greenhouse effect and the ability of the surface to radiate thermal energy directly to space. During the dry season, sunlight is balanced mainly by longwave radiation and the turbulent flux of sensible heat. The ability of longwave radiation to cool the surface drops after the onset of the West African summer monsoon, when moist, oceanic air flows onshore, increasing local column moisture and atmospheric opacity at these wavelengths. After the monsoon onset, but prior to significant rainfall, solar heating is compensated mainly by the sensible heat flux. During the rainy season, the magnitude of evaporation is initially controlled by the supply of moisture from precipitation. However, by the height of the rainy season, sufficient precipitation has accumulated at the surface that evaporation is related to the flux demanded by solar radiation, and radiative forcing of the surface is balanced comparably by the latent, sensible, and longwave fluxes. Radiative forcing of the surface also varies on a subseasonal time scale due to fluctuations in water vapor, clouds, and aerosol concentration. Except at the height of the rainy season, subseasonal forcing is balanced mainly by sensible heating and longwave anomalies. The efficacy of the sensible heat flux

  3. Influence of seasonal timing on thermal ecology and thermal reaction norm evolution in Wyeomyia smithii.

    PubMed

    Ragland, G J; Kingsolver, J G

    2007-11-01

    Evolutionary changes in the seasonal timing of life-history events can alter a population's exposure to seasonally variable environmental factors. We illustrate this principle in Wyeomyia smithii by showing that: (1) geographic divergence in diapause timing reduces differences among populations in the thermal habitat experienced by nondiapause stages; and (2) the thermal habitat of the growing season is more divergent at high compared with low temperatures with respect to daily mean temperatures. Geographic variation in thermal reaction norms for development time was greater in a warm compared with a cool rearing treatment, mirroring the geographic trend in daily mean temperature. Geographic variation in body size was unrelated to geographic temperature variation, but was also unrelated to development time or fecundity. Our results suggest that proper interpretation of geographic trends may often require detailed knowledge of life-history timing.

  4. Thermal energy storage devices, systems, and thermal energy storage device monitoring methods

    DOEpatents

    Tugurlan, Maria; Tuffner, Francis K; Chassin, David P.

    2016-09-13

    Thermal energy storage devices, systems, and thermal energy storage device monitoring methods are described. According to one aspect, a thermal energy storage device includes a reservoir configured to hold a thermal energy storage medium, a temperature control system configured to adjust a temperature of the thermal energy storage medium, and a state observation system configured to provide information regarding an energy state of the thermal energy storage device at a plurality of different moments in time.

  5. Seasonal variability of eddy kinetic energy in a global high-resolution ocean model

    NASA Astrophysics Data System (ADS)

    Rieck, Jan K.; Böning, Claus W.; Greatbatch, Richard J.; Scheinert, Markus

    2015-11-01

    A global ocean model with 1/12° horizontal resolution is used to assess the seasonal cycle of surface eddy kinetic energy (EKE). The model reproduces the salient features of the observed mean surface EKE, including amplitude and phase of its seasonal cycle in most parts of the ocean. In all subtropical gyres of the Pacific and Atlantic, EKE peaks in summer down to a depth of ˜350 m, below which the seasonal cycle is weak. Investigation of the possible driving mechanisms reveals the seasonal changes in the thermal interactions with the atmosphere to be the most likely cause of the summer maximum of EKE. The development of the seasonal thermocline in spring and summer is accompanied by stronger mesoscale variations in the horizontal temperature gradients near the surface which corresponds, by thermal wind balance, to an intensification of mesoscale velocity anomalies toward the surface.

  6. Seasonal storage of energy in solar heating

    NASA Astrophysics Data System (ADS)

    Braun, J. E.; Klein, S. A.; Mitchell, J. W.

    1981-01-01

    This paper focuses on several aspects of seasonal storage for space heating using water as the storage medium. The interrelationships between collector area, storage volume, and system performance are investigated using the transient simulation program TRNSYS. The situations for which seasonal storage is most promising are presented. Particular emphasis is placed upon design of seasonal storage systems. A design method is presented which is applicable for storage capacities ranging from a few days to seasonal storage. This design method, coupled with cost information, should be useful in assessing the economic viability of seasonal storage systems. Also investigated are the importance of the load heat exchanger size, tank insulation, collector slope, and year-to-year weather variations in system design.

  7. Microwavable thermal energy storage material

    DOEpatents

    Salyer, I.O.

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments. 3 figs.

  8. Microwavable thermal energy storage material

    DOEpatents

    Salyer, Ival O.

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene-vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments.

  9. Titan's Seasonal Changes Observed in the Thermal Infrared (Invited)

    NASA Astrophysics Data System (ADS)

    Jennings, D. E.; Anderson, C. M.; Nixon, C. A.; Bjoraker, G. L.; Achterberg, R. K.; Flasar, F.; Cottini, V.; Coustenis, A.; Vinatier, S.; Teanby, N. A.; Bampasidis, G.

    2013-12-01

    A central goal of the Cassini Mission is the detection and tracking of seasonal variations on Titan. Cassini arrived in the Saturn system in late northern winter and has so far observed for almost four Titan months, enough time to see significant changes as solar warming has moved northward. In the thermal infrared the shift has been apparent both in emission from the atmosphere and temperatures at the surface. Gases, clouds and aerosols in the atmosphere warm and cool with the seasons, accumulate and dissipate, and undergo transport on a global scale. Warming of the surface helps drive the exchange of heat and volatiles with the atmosphere, which contributes to weather. Seasonal activity in the north can be expected to be repeated in the south over the course of a year, so that it may be possible by the end of the Cassini Mission to combine winter-spring data from the north and summer-autumn data from the south to build up a picture that covers almost a full annual cycle. The Composite Infrared Spectrometer (CIRS) on Cassini records thermal infrared spectra in the 7-1000 micron range. CIRS has found that surface temperatures at Titan's poles are about 2.5 K lower than near the equator and that the temperatures moved from peaking south of the equator in 2005 to being approximately centered at the equator in 2011. As Titan passed through equinox in 2009, CIRS watched as atmospheric patterns that had been associated with northern winter began to emerge in the south. Emission from stratospheric gases and condensates varied dramatically as temperatures, chemistry and transport configurations adjusted to the season. Complex nitriles that had only been present at high northern latitudes began to appear near the South Pole while a polar ice cloud, originally identified in the north by its spectral emission, made an abrupt debut in the south. We expect much more evidence of seasonal evolution in the thermal infrared as CIRS continues to study Titan through the remainder of

  10. Thermal energy storage flight experiments

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1989-01-01

    Consideration is given to the development of an experimental program to study heat transfer, energy storage, fluid movement, and void location under microgravity. Plans for experimental flight packages containing Thermal Energy Storage (TES) material applicable for advanced solar heat receivers are discussed. Candidate materials for TES include fluoride salts, salt eutectics, silicides, and metals. The development of a three-dimensional computer program to describe TES material behavior undergoing melting and freezing under microgravity is also discussed. The TES experiment concept and plans for ground and flight tests are outlined.

  11. CALORSTOCK 1994: Thermal energy storage. Better economy, environment, technology

    NASA Astrophysics Data System (ADS)

    Kangas, M. T.; Lund, P. D.

    This publication is the second volume of the Proceedings of CALORSTOCK'94, the Sixth International Conference on Thermal Energy Storage held in Espoo, Finland on 22-25 Aug. 1994. This volume contains 51 presentations from the following six sessions: Chemical storage; Heat storage and environment; Central solar heating plants with seasonal storage; Water storage pits and tanks; Cooling; and National activities.

  12. More Efficient Solar Thermal-Energy Receiver

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.

    1987-01-01

    Thermal stresses and reradiation reduced. Improved design for solar thermal-energy receiver overcomes three major deficiencies of solar dynamic receivers described in literature. Concentrator and receiver part of solar-thermal-energy system. Receiver divided into radiation section and storage section. Concentrated solar radiation falls on boiling ends of heat pipes, which transmit heat to thermal-energy-storage medium. Receiver used in number of applications to produce thermal energy directly for use or to store thermal energy for subsequent use in heat engine.

  13. Energy from ocean thermal gradients

    NASA Astrophysics Data System (ADS)

    Cohen, R.

    1980-02-01

    Ocean Thermal Energy Conversion (OTEC) transforms the solar heating of the ocean surface into electrical energy, either transmitting it to shore or using it to manufacture energy-intensive products such as aluminum, ammonia, hydrogen or magnesium at sea. Open-cycle systems, requiring extremely large turbines and degasifiers, are not thought to be as advanced as closed-cycle systems which use heat exchangers (either shell-and-tube or plate) that are made of titanium, stainless steel or aluminum alloys, which must minimize corrosion and biofouling, and that use ammonia, propane or fluorocarbons as working fluids. OTEC platform configurations include ship shapes and submersibles, such as spar buoys, and require cold-water pipes 1,000 m long, made of such materials as elastomers, lightweight concrete and fiberglass-reinforced plastic.

  14. Ocean thermal-energy conversion

    NASA Astrophysics Data System (ADS)

    Ford, G.; Niblett, C.; Walker, L.

    1983-03-01

    The principles underlying ocean thermal-energy conversion (OTEC) are reviewed, and a schematic layout of a system is included. The two systems currently under study, the open system and the closed system, are described. The prospect now, it is noted, is that OTEC plants will not be commercially viable on a widespread basis, even in the tropics. This is especially true of the large-scale plants that have been envisioned. A strong possibility is seen, however, that smaller plants, generating about 40 megawatts of electrical power, can survive commercially. The following conditions would favor their success: placement on land rather than at sea; placement in areas (such as islands) where alternative energy supplies are at a premium; and designing the plant to operate in conjunction with either an aquaculture or a desalination plant.

  15. Solar energy thermally powered electrical generating system

    NASA Technical Reports Server (NTRS)

    Owens, William R. (Inventor)

    1989-01-01

    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  16. Skilful seasonal predictions for the European energy industry

    NASA Astrophysics Data System (ADS)

    Clark, Robin T.; Bett, Philip E.; Thornton, Hazel E.; Scaife, Adam A.

    2017-02-01

    We assess the utility of seasonal forecasts for the energy industry by showing how recently-established predictability of the North Atlantic Oscillation (NAO) in winter allows predictability of near-surface wind speed and air temperature and therefore energy supply and demand respectively. Our seasonal prediction system (GloSea5) successfully reproduces the influence of the NAO on European climate, leading to skilful forecasts of wind speed and wind power and hence wind driven energy supply. Temperature is skilfully forecast using the observed temperature-NAO relationship and the NAO forecast. Using the correlation between forecast NAO and observed GB electricity demand, we demonstrate that skilful predictions of winter demand are also achievable on seasonal timescales well in advance of the season. Finally, good reliability of probabilistic forecasts of above/below-average wind speed and temperature is also demonstrated.

  17. Thermal Energy Harvesting from Wildlife

    NASA Astrophysics Data System (ADS)

    Woias, P.; Schule, F.; Bäumke, E.; Mehne, P.; Kroener, M.

    2014-11-01

    In this paper we present the measurement of temperature differences between the ambient air and the body temperature of a sheep (Heidschnucke) and its applicability for thermoelectric energy harvesting from livestock, demonstrated via the test of a specially tailored TEG system in a real-life experiment. In three measurement campaigns average temperature differences were found between 2.5 K and 3.5 K. Analytical models and FEM simulations were carried out to determine the actual thermal resistance of the sheep's fur from comparisons with the temperature measurements. With these data a thermoelectric (TEG) generator was built in a thermally optimized housing with adapted heats sink. The whole TEG system was mounted to a collar, including a data logger for recording temperature and TEG voltage. First measurements at the neck of a sheep were accomplished, with a calculated maximal average power output of 173 μW at the TEG. Taking the necessity of a low-voltage step-up converter into account, an electric output power of 54 μW is available which comes close to the power consumption of a low-power VHF tracking system.

  18. Thermal energy management process experiment

    NASA Technical Reports Server (NTRS)

    Ollendorf, S.

    1984-01-01

    The thermal energy management processes experiment (TEMP) will demonstrate that through the use of two-phase flow technology, thermal systems can be significantly enhanced by increasing heat transport capabilities at reduced power consumption while operating within narrow temperature limits. It has been noted that such phenomena as excess fluid puddling, priming, stratification, and surface tension effects all tend to mask the performance of two-phase flow systems in a 1-g field. The flight experiment approach would be to attack the experiment to an appropriate mounting surface with a 15 to 20 meter effective length and provide a heat input and output station in the form of heaters and a radiator. Using environmental data, the size, location, and orientation of the experiment can be optimized. The approach would be to provide a self-contained panel and mount it to the STEP through a frame. A small electronics package would be developed to interface with the STEP avionics for command and data handling. During the flight, heaters on the evaporator will be exercised to determine performance. Flight data will be evaluated against the ground tests to determine any anomalous behavior.

  19. Solar energy thermalization and storage device

    DOEpatents

    McClelland, J.F.

    A passive solar thermalization and thermal energy storage assembly which is visually transparent is described. The assembly consists of two substantial parallel, transparent wall members mounted in a rectangular support frame to form a liquid-tight chamber. A semitransparent thermalization plate is located in the chamber, substantially paralled to and about equidistant from the transparent wall members to thermalize solar radiation which is stored in a transparent thermal energy storage liquid which fills the chamber. A number of the devices, as modules, can be stacked together to construct a visually transparent, thermal storage wall for passive solar-heated buildings.

  20. Solar energy thermalization and storage device

    DOEpatents

    McClelland, John F.

    1981-09-01

    A passive solar thermalization and thermal energy storage assembly which is visually transparent. The assembly consists of two substantial parallel, transparent wall members mounted in a rectangular support frame to form a liquid-tight chamber. A semitransparent thermalization plate is located in the chamber, substantially paralled to and about equidistant from the transparent wall members to thermalize solar radiation which is stored in a transparent thermal energy storage liquid which fills the chamber. A number of the devices, as modules, can be stacked together to construct a visually transparent, thermal storage wall for passive solar-heated buildings.

  1. Smart Building: Decision Making Architecture for Thermal Energy Management.

    PubMed

    Uribe, Oscar Hernández; Martin, Juan Pablo San; Garcia-Alegre, María C; Santos, Matilde; Guinea, Domingo

    2015-10-30

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

  2. Smart Building: Decision Making Architecture for Thermal Energy Management

    PubMed Central

    Hernández Uribe, Oscar; San Martin, Juan Pablo; Garcia-Alegre, María C.; Santos, Matilde; Guinea, Domingo

    2015-01-01

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction. PMID:26528978

  3. High-energy thermal synchrotron emission

    NASA Technical Reports Server (NTRS)

    Imamura, J. N.; Epstein, R. I.; Petrosian, V.

    1985-01-01

    It is shown how the thermal synchrotron emission spectrum is modified when the photon energy is greater than the mean energy of the radiating particles. The effect if applying this energy conservation constraint is to produce spectra which have less high-energy photon emission than had been previously estimated. The thermal synchrotron spectra provide satisfactory fits to recently observed very high energy gamma ray spectra of certain burst sources.

  4. Passive solar/Earth sheltered office/dormitory cooling season thermal performance

    NASA Astrophysics Data System (ADS)

    Christian, J.

    1984-06-01

    Continuous detailed hourly thermal performance measurements were taken since February 1982 in and around an occupied, underground, 4000 ft(2) office/dormitory building at the Oak Ridge National Laboratory in Oak Ridge, Tennessee. This building has a number of energy saving features which were analyzed relative to their performance in a southeastern US climate and with respect to overall commercial building performance. Cooling season performance is documented, as well as effects of earth constact, interior thermal mass, an economizer cycle and interface of an efficient building envelope with a central three-ton heat pump. The Joint Institute Dormitory obtains a cooling energy savings of about 30% compared with an energy-efficient, above-grade structure and has the potential to save as much as 50%. The proper instllation of the overhand, interior thermal mass, massive supply duct system, and earth contact team up to prevent summertime overheating. From May through September, this building cost a total of $300 (at 5.7) cents/kWh) to cool and ventilate 24 hours per day. Besides thermal performance of the building envelope, extensive comfort data was taken illustrating that at least 90% of the occupants are comfortable all of the time according to the PMV measurements.

  5. Seasonal modulations of the underground cosmic-ray muon energy

    SciTech Connect

    Malgin, A. S.

    2015-08-15

    The parameters of the seasonal modulations in the intensity of muons and cosmogenic neutrons generated by them at a mean muon energy of 280 GeV have been determined in the LVD (Large Volume Detector) experiment. The modulations of muons and neutrons are caused by a temperature effect, the seasonal temperature and density variations of the upper atmospheric layers. The analysis performed here leads to the conclusion that the variations in the mean energy of the muon flux are the main source of underground cosmogenic neutron variations, because the energy of muons is more sensitive to the temperature effect than their intensity. The parameters of the seasonal modulations in the mean energy of muons and the flux of cosmogenic neutrons at the LVD depth have been determined from the data obtained over seven years of LVD operation.

  6. The impact of seasonality in temperature on thermal tolerance and elevational range size.

    PubMed

    Sheldon, Kimberly S; Tewksbury, Joshua J

    2014-08-01

    Environmental temperature variation can influence physiology, biogeography, and life history, with large consequences for ecology, evolution, and the impacts of climate change. Based on the seasonality hypothesis, greater annual temperature variation at high latitudes should result in greater thermal tolerance and, consequently, larger elevational ranges in temperate compared to tropical species. Despite the mechanistic nature of this hypothesis, most research has used latitude as a proxy for seasonality, failing to directly examine the impact of temperature variation on physiology and range size. We used phylogenetically matched beetles from locations spanning 60 degrees of latitude to explore links between seasonality, physiology and elevational range. Thermal tolerance increased with seasonality across all beetle groups, but realized seasonality (temperature variation restricted to the months species are active) was a better predictor of thermal tolerance than was annual seasonality. Additionally, beetles with greater thermal tolerance had larger elevational ranges. Our results support a mechanistic framework linking variation in realized temperature to physiology and distributions.

  7. Seasonal energy and evapotranspiration partitioning in a desert vineyard

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The challenge of partitioning energy and evapotranspiration (ET) components was addressed over a season (bud break till harvest) in a wine grape vineyard located in an extreme arid region. A below canopy energy balance approach was applied to continuously estimate evaporation from the soil (E) while...

  8. Thermal comfort of people in the hot and humid area of China-impacts of season, climate, and thermal history.

    PubMed

    Zhang, Y; Chen, H; Wang, J; Meng, Q

    2016-10-01

    We conducted a climate chamber study on the thermal comfort of people in the hot and humid area of China. Sixty subjects from naturally ventilated buildings and buildings with split air conditioners participated in the study, and identical experiments were conducted in a climate chamber in both summer and winter. Psychological and physiological responses were observed over a wide range of conditions, and the impacts of season, climate, and thermal history on human thermal comfort were analyzed. Seasonal and climatic heat acclimatization was confirmed, but they were found to have no significant impacts on human thermal sensation and comfort. The outdoor thermal history was much less important than the indoor thermal history in regard to human thermal sensation, and the indoor thermal history in all seasons of a year played a key role in shaping the subjects' sensations in a wide range of thermal conditions. A warmer indoor thermal history in warm seasons produced a higher neutral temperature, a lower thermal sensitivity, and lower thermal sensations in warm conditions. The comfort and acceptable conditions were identified for people in the hot and humid area of China.

  9. Thermal energy storage apparatus, controllers and thermal energy storage control methods

    DOEpatents

    Hammerstrom, Donald J.

    2016-05-03

    Thermal energy storage apparatus, controllers and thermal energy storage control methods are described. According to one aspect, a thermal energy storage apparatus controller includes processing circuitry configured to access first information which is indicative of surpluses and deficiencies of electrical energy upon an electrical power system at a plurality of moments in time, access second information which is indicative of temperature of a thermal energy storage medium at a plurality of moments in time, and use the first and second information to control an amount of electrical energy which is utilized by a heating element to heat the thermal energy storage medium at a plurality of moments in time.

  10. Seasonal adaptations in energy budgeting in the primate Lepilemur leucopus.

    PubMed

    Bethge, Janina; Wist, Bianca; Stalenberg, Eleanor; Dausmann, Kathrin

    2017-03-17

    The spiny forest of South Madagascar is one of the driest and most unpredictable habitats in Africa. The small-bodied, nocturnal primate Lepilemur leucopus lives in this harsh habitat with high diurnal and seasonal changes in ambient temperature. In this study, we investigated seasonal adaptions in energy budgeting of L. leucopus, which allow it to live under these conditions by measuring resting metabolic rate using open-flow respirometry. No signs of heterothermy were detected, and resting metabolic rate was significantly lower in the warmer wet season than in the colder dry season. In fact, L. leucopus possesses one of the lowest mass-specific metabolic rates measured so far for an endotherm, probably the result of adaptations to its habitat and folivorous and potentially toxic diet. Surprisingly, we identified a shift of the thermoneutral zone from between 25 and 30 °C in the wet season to between 29 and 32 °C in the cool dry season. L. leucopus seems to be more affected by the hot daytime temperatures during the dry season and thermoregulation seems to be more costly during this time, which makes this shift of the thermoneutral zone advantageous. Our findings suggest that L. leucopus has a very small scope to unfavorable conditions, making it highly vulnerable, e.g., to changing conditions due to climate change.

  11. The influence of thermal insulation position in building exterior walls on indoor thermal comfort and energy consumption of residential buildings in Chongqing

    NASA Astrophysics Data System (ADS)

    Wang, D.; Yu, W.; Zhao, X.; Dai, W.; Ruan, Y.

    2016-08-01

    This paper focused on the influence of using position of thermal insulation materials in exterior walls on the indoor thermal comfort and building energy consumption of residential building in Chongqing. In this study, four (4) typical residential building models in Chongqing were established, which have different usage of thermal insulation layer position in exterior walls. Indoor thermal comfort hours, cooling and heating energy consumption of each model were obtained by using a simulation tool, Energyplus. Based on the simulation data, the influence of thermal insulation position on indoor thermal comfort and building energy consumption in each season was analyzed. The results showed that building with internal insulation had the highest indoor thermal comfort hours and least cooling and heating energy consumption in summer and winter. In transitional season, the highest indoor thermal comfort hours are obtained when thermal insulation is located on the exterior side.

  12. Hybrid energy harvesting using active thermal backplane

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Wook; Lee, Dong-Gun

    2016-04-01

    In this study, we demonstrate the concept of a new hybrid energy harvesting system by combing solar cells with magneto-thermoelectric generator (MTG, i.e., thermal energy harvesting). The silicon solar cell can easily reach high temperature under normal operating conditions. Thus the heated solar cell becomes rapidly less efficient as the temperature of solar cell rises. To increase the efficiency of the solar cell, air or water-based cooling system is used. To surpass conventional cooling devices requiring additional power as well as large working space for air/water collectors, we develop a new technology of pairing an active thermal backplane (ATB) to solar cell. The ATB design is based on MTG technology utilizing the physics of the 2nd order phase transition of active ferromagnetic materials. The MTG is cost-effective conversion of thermal energy to electrical energy and is fundamentally different from Seebeck TEG devices. The ATB (MTG) is in addition to being an energy conversion system, a very good conveyor of heat through both conduction and convection. Therefore, the ATB can provide dual-mode for the proposed hybrid energy harvesting. One is active convective and conductive cooling for heated solar cell. Another is active thermal energy harvesting from heat of solar cell. These novel hybrid energy harvesting device have potentially simultaneous energy conversion capability of solar and thermal energy into electricity. The results presented can be used for better understanding of hybrid energy harvesting system that can be integrated into commercial applications.

  13. Thermal Comfort and Strategies for Energy Conservation.

    ERIC Educational Resources Information Center

    Rohles, Frederick H., Jr.

    1981-01-01

    Discusses studies in thermal comfort which served as the basis for the comfort standard. Examines seven variables in the human response to the thermal environment in terms of the ways in which they can be modified to conserve energy. (Author/MK)

  14. Energy conservation, using remote thermal scanning

    NASA Technical Reports Server (NTRS)

    Bowman, R. L.; Jack, J. R.

    1978-01-01

    Airborne thermal infrared scans and thermal maps utilized in NASA's energy conservation program have proven to be efficient cost-effective method for identifying heat losses from building roofs and heating system distribution lines. Method employs commercially available equipment in highly developed way.

  15. TES (Thermal Energy Storage) Video News Release

    NASA Technical Reports Server (NTRS)

    1994-01-01

    TES is an in-space technology experiment that flew on STS-62. Its intent is to investigate the behavior of two different thermal energy storage materials as they undergo repeated melting and freezing in the microgravity environment.

  16. Efficient hybrid electric and thermal energy generation

    NASA Astrophysics Data System (ADS)

    Xia, X. Winston; Parfenov, Alexander V.; Aye, Tin M.; Shih, Min-Yi

    2011-10-01

    We demonstrate a novel hybrid solar photovoltaic electrical and thermal energy cogeneration system with high efficiency, at potentially reduced overall weight and size compared with current solar energy systems. The new system is based on highly efficient photovoltaic solar cells and tubular water thermal receivers, incorporating holographic spectral beam light guide concentrators resulting in a more cost-effective solution. Details of fabrication and preliminary experimental testing results are presented.

  17. U.S. Department of Energy thermal energy storage research activities review: 1989 Proceedings

    SciTech Connect

    Hoffman, H.W.; Tomlinson, J.J.

    1989-03-01

    Thermal Energy Storage (TES) offers the opportunity for the recovery and re-use of heat currently rejected to the ambient environment. Further, through the ability of TES to match an energy supply with a thermal energy demand, TES increases efficiencies of energy systems and improves capacity factors of power plants. The US Department of Energy has been the leader in TES research, development, and demonstration since recognition in 1976 of the need for fostering energy conservation as a component of the national energy budget. The federal program on TES R and D is the responsibility of the Office of Energy Storage and Distribution within the US Department of Energy (DOE). The overall program is organized into three program areas: diurnal--relating primarily to lower temperature heat for use in residential and commercial buildings on a daily cycle; industrial--relating primarily to higher temperature heat for use in industrial and utility processes on an hourly to daily cycle; seasonal--relating primarily to lower temperature heat or chill for use in residential complexes (central supply as for apartments or housing developments), commercial (light manufacturing, processing, or retail), and industrial (space conditioning) on a seasonal to annual cycle. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  18. Ocean Thermal Energy Conversion: An overview

    SciTech Connect

    Not Available

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the US Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential -- either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. This publication provides an overview of the OTEC technology. 47 refs., 25 figs.

  19. Ocean thermal energy conversion: An overview

    NASA Astrophysics Data System (ADS)

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the U.S. Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential; either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. An overview of the OTEC technology is provided.

  20. Application and verification of ECMWF seasonal forecast for wind energy

    NASA Astrophysics Data System (ADS)

    Žagar, Mark; Marić, Tomislav; Qvist, Martin; Gulstad, Line

    2015-04-01

    A good understanding of long-term annual energy production (AEP) is crucial when assessing the business case of investing in green energy like wind power. The art of wind-resource assessment has emerged into a scientific discipline on its own, which has advanced at high pace over the last decade. This has resulted in continuous improvement of the AEP accuracy and, therefore, increase in business case certainty. Harvesting the full potential output of a wind farm or a portfolio of wind farms depends heavily on optimizing operation and management strategy. The necessary information for short-term planning (up to 14 days) is provided by standard weather and power forecasting services, and the long-term plans are based on climatology. However, the wind-power industry is lacking quality information on intermediate scales of the expected variability in seasonal and intra-annual variations and their geographical distribution. The seasonal power forecast presented here is designed to bridge this gap. The seasonal power production forecast is based on the ECMWF seasonal weather forecast and the Vestas' high-resolution, mesoscale weather library. The seasonal weather forecast is enriched through a layer of statistical post-processing added to relate large-scale wind speed anomalies to mesoscale climatology. The resulting predicted energy production anomalies, thus, include mesoscale effects not captured by the global forecasting systems. The turbine power output is non-linearly related to the wind speed, which has important implications for the wind power forecast. In theory, the wind power is proportional to the cube of wind speed. However, due to the nature of turbine design, this exponent is close to 3 only at low wind speeds, becomes smaller as the wind speed increases, and above 11-13 m/s the power output remains constant, called the rated power. The non-linear relationship between wind speed and the power output generally increases sensitivity of the forecasted power

  1. Enhancing radiative energy transfer through thermal extraction

    NASA Astrophysics Data System (ADS)

    Tan, Yixuan; Liu, Baoan; Shen, Sheng; Yu, Zongfu

    2016-06-01

    Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics. Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal

  2. Solar energy system performance evaluation: Seasonal report for SEMCO, Loxahatchee, Florida

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The operational and thermal performance of a variety of solar systems installed in operational test sites are described. The analysis used is based on instrumented system data monitored and collected for at least one full season of operation. The long-term field performance of the installed system and the technical contributions to the definition of techniques and requirements solar energy system design are analyzed. The solar energy system was designed to supply domestic hot water for a family of four, single-family residences. It consists of two liquid flat plate collectors, single tank, controls, and transport lines.

  3. Solar energy system performance evaluation: Seasonal report for SEMCO. Loxahatchee, Florida

    NASA Astrophysics Data System (ADS)

    1980-01-01

    The operational and thermal performance of a variety of solar systems installed in operational test sites are described. The analysis used is based on instrumented system data monitored and collected for at least one full season of operation. The long-term field performance of the installed system and the technical contributions to the definition of techniques and requirements solar energy system design are analyzed. The solar energy system was designed to supply domestic hot water for a family of four, single-family residences. It consists of two liquid flat plate collectors, single tank, controls, and transport lines.

  4. Solar energy system performance evaluation: Seasonal report for fern, Tunkhannock, Pennsylvania

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The operational and thermal performance of a variety of solar systems installed in operational test sites are described. The analysis is based on instrumented system data monitored and collected for at least one full season of operation. The long-term field performance of the installed system is reported, and technical contributions to the definition of techniques and requirements for solar energy system design are made. The solar energy system was designed to supply space heating and domestic hot water for single-family residences. The system consists of air flat plate collectors, storage tank, pumps, heat exchangers, associated plumbing, and controls.

  5. A thermal model for the seasonal nitrogen cycle on Triton

    NASA Technical Reports Server (NTRS)

    Hansen, Candice J.; Paige, David A.

    1992-01-01

    The seasonal N2-cycle model presently used to characterize such observed phenomena on Triton as atmospheric pressure and surface albedo features at the time of the Voyager encounter incorporates diurnal and seasonal subsurface heat conduction, and can account for the heat capacity of N2 frost deposits. The results obtained by this model differ from those of previous studies in that they do not predict the seasonal freezing-out of the Triton atmosphere; even for a wide range of input parameters, the bright southern polar cap is seen as rather unlikely to be N2. The results support the microphysical arguments for the presence of either dark or smooth translucent N2 frosts on the Triton surface.

  6. Thermal Energy Storage Flight Experiment in Microgravity

    NASA Technical Reports Server (NTRS)

    Namkoong, David

    1992-01-01

    The Thermal Energy Storage Flight Experiment was designed to characterize void shape and location in LiF-based phase change materials in different energy storage configurations representative of advanced solar dynamic systems. Experiment goals and payload design are described in outline and graphic form.

  7. Phase-Change Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    1989-11-01

    The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axes tracking mirrors) to focus the sun's radiant energy onto a single, tower-mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating working fluid. Receiver temperatures range from 100 C in low-temperature troughs to over 1500 C in dish and central receiver systems.

  8. The role of thermal energy storage in industrial energy conservation

    NASA Technical Reports Server (NTRS)

    Duscha, R. A.; Masica, W. J.

    1979-01-01

    Thermal Energy Storage for Industrial Applications is a major thrust of the Department of Energy's Thermal Energy Storage Program. Utilizing Thermal Energy Storage (TES) with process or reject heat recovery systems is shown to be extremely beneficial for several applications. Recent system studies resulting from contracts awarded by the Department of Energy (DOE) identified four especially significant industries where TES appears attractive - food processing, paper and pulp, iron and steel, and cement. Potential annual fuel savings with large scale implementation of near term TES systems for these industries is over 9,000,000 bbl of oil. This savings is due to recuperation and storage in the food processing industry, direct fuel substitution in the paper and pulp industry and reduction in electric utility peak fuel use through inplant production of electricity from utilization of reject heat in the steel and cement industries.

  9. Evaluation of New Thermally Conductive Geopolymer in Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    Černý, Matěj; Uhlík, Jan; Nosek, Jaroslav; Lachman, Vladimír; Hladký, Radim; Franěk, Jan; Brož, Milan

    This paper describes an evaluation of a newly developed thermally conductive geopolymer (TCG), consisting of a mixture of sodium silicate and carbon micro-particles. The TCG is intended to be used as a component of high temperature energy storage (HTTES) to improve its thermal diffusivity. Energy storage is crucial for both ecological and economical sustainability. HTTES plays a vital role in solar energy technologies and in waste heat recovery. The most advanced HTTES technologies are based on phase change materials or molten salts, but suffer with economic and technological limitations. Rock or concrete HTTES are cheaper, but they have low thermal conductivity without incorporation of TCG. It was observed that TCG is stable up to 400 °C. The thermal conductivity was measured in range of 20-23 W m-1 K-1. The effect of TCG was tested by heating a granite block with an artificial fissure. One half of the fissure was filled with TCG and the other with ballotini. 28 thermometers, 5 dilatometers and strain sensors were installed on the block. The heat transport experiment was evaluated with COMSOL Multiphysics software.

  10. New Results on the Seasonal Variations in Saturn's Thermal Plasma

    NASA Astrophysics Data System (ADS)

    Elrod, M. K.; Tseng, W.; Johnson, R. E.

    2012-12-01

    The region of the magnetosphere from the main rings to inside the orbit of Enceladus is populated by oxygen from the Saturn's ring atmosphere and water products from Enceladus. Therefore, we examined the CAPS plasma data for several equatorial periapsis passes from 2004 to 2012 for the region from 2.4 to 3.8 Saturn radii (~60,300 km) including Voyager 2 in order to separate the contributions from these two sources and to understand the temporal variations in the plasma. Because of the high background in this region, only eight orbits were used in this study. Using Voyager II data and CAPS data from 2004, and 2012 we show that large variations in ion density, temperature, and composition occur. Although the Enceladus plumes are variable, we propose that the large change in the ion density from 2004 to equinox near 2010 was likely due to the seasonal variation in the ring atmosphere (Elrod et al. 2012). Furthermore, when comparing the recent 2012 passes with the 2010 passes, where are much closer to Enceladus, and likely dominated by the water sources from this moon, we still see an increase in the signal between 2010 and 2012 indicating that there is likely still a seasonal variation throughout the region. This interpretation of the plasma data was in turn supported by a simple photochemical model which combined water products from Enceladus and with the seasonally variable oxygen from the the ring atmosphere (Tseng et al. 2012). In this presentation we will compare the results of our recent analysis of the 2012 data with our model for seasonal variations in the plasma source in this region. Elrod, M. K., W.-L. Tseng, R. J. Wilson, and R. E. Johnson (2012), Seasonal variations in Saturn's plasma between the main rings and Enceladus, J. Geophys. Res., 117, A03207, doi:10.1029/2011JA017332. Tseng, W.-L., et al., Modeling the seasonal variability of the plasma environment in Saturn's magnetosphere between main rings and Mimas. Planetary and Space Science (2012), http

  11. Molten Salt Thermal Energy Storage Systems

    NASA Technical Reports Server (NTRS)

    Maru, H. C.; Dullea, J. F.; Kardas, A.; Paul, L.; Marianowski, L. G.; Ong, E.; Sampath, V.; Huang, V. M.; Wolak, J. C.

    1978-01-01

    The feasibility of storing thermal energy at temperatures of 450 C to 535 C in the form of latent heat of fusion was examined for over 30 inorganic salts and salt mixtures. Alkali carbonate mixtures were chosen as phase-change storage materials in this temperature range because of their relatively high storage capacity and thermal conductivity, moderate cost, low volumetric expansion upon melting, low corrosivity, and good chemical stability. Means of improving heat conduction through the solid salt were explored.

  12. Seasonal changes in humidity impact drought resistance in tropical Drosophila leontia: testing developmental effects of thermal versus humidity changes.

    PubMed

    Parkash, Ravi; Ranga, Poonam

    2014-03-01

    Drosophila leontia is native to highly humid equatorial tropical habitats but its desiccation sensitivity (~10h) is not consistent with its abundance during the drier autumn season in the subtropical regions. We have tested the effects of developmental acclimation on desiccation resistance and water balance related traits of D. leontia collected during rainy and autumn seasons. The isofemale lines of seasonal populations were reared under ecologically relevant growth temperatures (18 or 26 °C) or humidity conditions (35 or 85% RH) but tested at different times under identical experimental conditions. The larvae as well as flies reared under two thermal conditions (18 or 26 °C) showed no effect on desiccation related traits as well as storage and utilization of energy metabolites. In contrast, for D. leontia reared under low humidity (35% RH), significant changes at larval as well adult stages include increase in the desiccation resistance as well as cuticular lipid quantity, reduced levels of rate of body water loss, higher storage of carbohydrates but lower rate of utilization of carbohydrates as compared with flies reared at high humidity (85% RH). D. leontia has responded to rearing under low humidity conditions by increasing its desiccation resistance but not due to changes in the growth temperatures. These laboratory observations on seasonal populations highlight differences due to rearing conditions but not due to seasons. Further, direct analysis of wild-caught seasonal populations has shown trends similar to developmental acclimation effects. For wild caught flies, there are significant seasonal differences i.e. higher desiccation resistance as well as cuticular lipid quantity but reduced rate of water loss for autumn than rainy season flies. Thus, our laboratory observations are relevant for understanding seasonal adaptations of natural populations of tropical D. leontia to wet-dry conditions in the wild.

  13. Thermal energy in Robertson-Walker universes

    NASA Astrophysics Data System (ADS)

    Ruiz, Fernando Ruiz

    1989-03-01

    The covariant functional Schrödinger formalism is used to study thermal equilibrium for a scalar field in Robertson-Walker spacetimes. It is found that thermal equilibrium can be maintained for field masses, coupling constants and geometries satisfying a given differential equation, of which the massless conformally coupled case is a solution, but not the only one. The thermal energy is computed; it contains a term which for particular geometries, such as de Sitter spacetime, grows in time. On leave of absence from Departamento de Física Teórica, Universidad Complutense, 28040 Madrid 3, Spain.

  14. Seasonal energy storage using bioenergy production from abandoned croplands

    NASA Astrophysics Data System (ADS)

    Campbell, J. Elliott; Lobell, David B.; Genova, Robert C.; Zumkehr, Andrew; Field, Christopher B.

    2013-09-01

    Bioenergy has the unique potential to provide a dispatchable and carbon-negative component to renewable energy portfolios. However, the sustainability, spatial distribution, and capacity for bioenergy are critically dependent on highly uncertain land-use impacts of biomass agriculture. Biomass cultivation on abandoned agriculture lands is thought to reduce land-use impacts relative to biomass production on currently used croplands. While coarse global estimates of abandoned agriculture lands have been used for large-scale bioenergy assessments, more practical technological and policy applications will require regional, high-resolution information on land availability. Here, we present US county-level estimates of the magnitude and distribution of abandoned cropland and potential bioenergy production on this land using remote sensing data, agriculture inventories, and land-use modeling. These abandoned land estimates are 61% larger than previous estimates for the US, mainly due to the coarse resolution of data applied in previous studies. We apply the land availability results to consider the capacity of biomass electricity to meet the seasonal energy storage requirement in a national energy system that is dominated by wind and solar electricity production. Bioenergy from abandoned croplands can supply most of the seasonal storage needs for a range of energy production scenarios, regions, and biomass yield estimates. These data provide the basis for further down-scaling using models of spatially gridded land-use areas as well as a range of applications for the exploration of bioenergy sustainability.

  15. Thermal energy harvesting plasmonic based chemical sensors.

    PubMed

    Karker, Nicholas; Dharmalingam, Gnanaprakash; Carpenter, Michael A

    2014-10-28

    Detection of gases such as H2, CO, and NO2 at 500 °C or greater requires materials with thermal stability and reliability. One of the major barriers toward integration of plasmonic-based chemical sensors is the requirement of multiple components such as light sources and spectrometers. In this work, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The combination of a plasmonic-based energy harvesting sensing paradigm with PCA analysis offers a novel path toward simplification and integration of plasmonic-based sensing methods.

  16. Spatial distribution of thermal energy in equilibrium.

    PubMed

    Bar-Sinai, Yohai; Bouchbinder, Eran

    2015-06-01

    The equipartition theorem states that in equilibrium, thermal energy is equally distributed among uncoupled degrees of freedom that appear quadratically in the system's Hamiltonian. However, for spatially coupled degrees of freedom, such as interacting particles, one may speculate that the spatial distribution of thermal energy may differ from the value predicted by equipartition, possibly quite substantially in strongly inhomogeneous or disordered systems. Here we show that for systems undergoing simple Gaussian fluctuations around an equilibrium state, the spatial distribution is universally bounded from above by 1/2k(B)T. We further show that in one-dimensional systems with short-range interactions, the thermal energy is equally partitioned even for coupled degrees of freedom in the thermodynamic limit and that in higher dimensions nontrivial spatial distributions emerge. Some implications are discussed.

  17. Cost-Effective Solar Thermal Energy Storage: Thermal Energy Storage With Supercritical Fluids

    SciTech Connect

    2011-02-01

    Broad Funding Opportunity Announcement Project: UCLA and JPL are creating cost-effective storage systems for solar thermal energy using new materials and designs. A major drawback to the widespread use of solar thermal energy is its inability to cost-effectively supply electric power at night. State-of-the-art energy storage for solar thermal power plants uses molten salt to help store thermal energy. Molten salt systems can be expensive and complex, which is not attractive from a long-term investment standpoint. UCLA and JPL are developing a supercritical fluid-based thermal energy storage system, which would be much less expensive than molten-salt-based systems. The team’s design also uses a smaller, modular, single-tank design that is more reliable and scalable for large-scale storage applications.

  18. Seasonal and radial trends in Saturn’s thermal plasma between the main rings and Enceladus

    NASA Astrophysics Data System (ADS)

    Elrod, M. K.; Tseng, W.-L.; Woodson, A. K.; Johnson, R. E.

    2014-11-01

    A goal of Cassini's extended mission is to examine the seasonal variations of Saturn's magnetosphere, moons, and rings. Recently we showed that the thermal plasma between the main rings and Enceladus exhibited a time dependence that we attributed to a seasonally variable source of oxygen from the main rings (Elrod, M.K., Tseng, W.-L., Wilson, R.J., Johnson, R.E. [2012]. J. Geophys. Res. 117, A03207. http://dx.doi.org/10.1029/2011JA017332). Such a temporal variation was subsequently seen in the energetic ion composition (Christon, S.P., Hamilton, D.C., DiFabio, R.D., Mitchel, D.G., Krimigis, S.M., Jontof-Hutter, D.S. [2013]. J. Geophys. Res. 28. http://dx.doi.org/10.1002/jgra.50383; Christon, S.P., Hamilton, D.C., Mitchell, D.G., DiFabio, R.D., Krimigis, S.M. [2014]. J. Geophys. Res., submitted for publication). Here we incorporate the most recent measurements by the Cassini Plasma Spectrometer (CAPS) into our earlier analysis (Elrod, M.K., Tseng, W.-L., Wilson, R.J., Johnson, R.E. [2012]. J. Geophys. Res. 117, A03207. http://dx.doi.org/10.1029/2011JA017332) and our modeling (Tseng, W.-L., Johnson, R.E., Elrod, M.K. [2013a]. Planet. Space Sci. 77, 126-135) of the thermal plasma in the region between the main rings and the orbit of Enceladus. Data taken in 2012, well past equinox for which the northern side of the main rings were illuminated, appear consistent with a seasonal variation. Although the thermal plasma in this region comes from two sources that have very different radial and temporal trends, the extended ring atmosphere and the Enceladus torus, the heavy ion density is found to exhibit a steep radial dependence that is similar for the years examined. Using our chemical model, we show that this dependence requires either a radial dependence for Enceladus torus that differs significantly from recent models or, as we suggest here, enhanced heavy ion quenching/neutralization with decreasing distance from the edge of the main rings. We examine the possible

  19. Spacecraft thermal energy accommodation from atomic recombination

    NASA Technical Reports Server (NTRS)

    Carleton, Karen L.; Marinelli, William J.

    1991-01-01

    Measurements of atomic recombination probabilities important in determining energy release to reusable spacecraft thermal protection surfaces during reentry are presented. An experimental apparatus constructed to examine recombination of atomic oxygen from thermal protection and reference materials at reentry temperatures is described. The materials are examined under ultrahigh vacuum conditions to develop and maintain well characterized surface conditions that are free of contamination. When compared with stagnation point heat transfer measurements performed in arc jet facilities, these measurements indicate that a significant fraction of the excess energy available from atom recombination is removed from the surface as metastable O2.

  20. LiH thermal energy storage device

    DOEpatents

    Olszewski, M.; Morris, D.G.

    1994-06-28

    A thermal energy storage device for use in a pulsed power supply to store waste heat produced in a high-power burst operation utilizes lithium hydride as the phase change thermal energy storage material. The device includes an outer container encapsulating the lithium hydride and an inner container supporting a hydrogen sorbing sponge material such as activated carbon. The inner container is in communication with the interior of the outer container to receive hydrogen dissociated from the lithium hydride at elevated temperatures. 5 figures.

  1. Thermal energy recycling fuel cell arrangement

    DOEpatents

    Hanrahan, Paul R.

    2017-04-11

    An example fuel cell arrangement includes a fuel cell stack configured to receive a supply fluid and to provide an exhaust fluid that has more thermal energy than the supply fluid. The arrangement also includes an ejector and a heat exchanger. The ejector is configured to direct at least some of the exhaust fluid into the supply fluid. The heat exchanger is configured to increase thermal energy in the supply fluid using at least some of the exhaust fluid that was not directed into the supply fluid.

  2. Aquifer thermal energy storage. International symposium: Proceedings

    SciTech Connect

    1995-05-01

    Aquifers have been used to store large quantities of thermal energy to supply process cooling, space cooling, space heating, and ventilation air preheating, and can be used with or without heat pumps. Aquifers are used as energy sinks and sources when supply and demand for energy do not coincide. Aquifer thermal energy storage may be used on a short-term or long-term basis; as the sole source of energy or as a partial storage; at a temperature useful for direct application or needing upgrade. The sources of energy used for aquifer storage are ambient air, usually cold winter air; waste or by-product energy; and renewable energy such as solar. The present technical, financial and environmental status of ATES is promising. Numerous projects are operating and under development in several countries. These projects are listed and results from Canada and elsewhere are used to illustrate the present status of ATES. Technical obstacles have been addressed and have largely been overcome. Cold storage in aquifers can be seen as a standard design option in the near future as it presently is in some countries. The cost-effectiveness of aquifer thermal energy storage is based on the capital cost avoidance of conventional chilling equipment and energy savings. ATES is one of many developments in energy efficient building technology and its success depends on relating it to important building market and environmental trends. This paper attempts to provide guidance for the future implementation of ATES. Individual projects have been processed separately for entry onto the Department of Energy databases.

  3. Applications and challenges for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Kannberg, L. D.; Tomlinson, J. T.

    1991-04-01

    New thermal energy storage (TES) technologies are being developed and applied as society strives to relieve increasing energy and environmental stresses. Applications for these new technologies range from residential and district heating and cooling using waste and solar energy, to high-temperature energy storage for power production and industrial processes. In the last two decades there has been great interest and development of heat storage systems, primarily for residential and commercial buildings. While development has continued, the rate of advancement has slowed with current technology considered adequate for electrically charged heat storage furnaces. Use of chill storage for building diurnal cooling has received substantial development.

  4. Thermal Insulation Strips Conserve Energy

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Launching the space shuttle involves an interesting paradox: While the temperatures inside the shuttle s main engines climb higher than 6,000 F hot enough to boil iron for fuel, the engines use liquid hydrogen, the second coldest liquid on Earth after liquid helium. Maintained below 20 K (-423 F), the liquid hydrogen is contained in the shuttle s rust-colored external tank. The external tank also contains liquid oxygen (kept below a somewhat less chilly 90 K or -297 F) that combines with the hydrogen to create an explosive mixture that along with the shuttle s two, powdered aluminum-fueled solid rocket boosters allows the shuttle to escape Earth s gravity. The cryogenic temperatures of the main engines liquid fuel can cause ice, frost, or liquefied air to build up on the external tank and other parts of the numerous launch fueling systems, posing a possible debris risk when the ice breaks off during launch and causing difficulties in the transfer and control of these cryogenic liquid propellants. Keeping the fuel at the necessary ultra-cold temperatures while minimizing ice buildup and other safety hazards, as well as reducing the operational maintenance costs, has required NASA to explore innovative ways for providing superior thermal insulation systems. To address the challenge, the Agency turned to an insulating technology so effective that, even though it is mostly air, a thin sheet can prevent a blowtorch from igniting a match. Aerogels were invented in 1931 and demonstrate properties that make them the most extraordinary insulating materials known; a 1-inch-thick piece of aerogel provides the same insulation as layering 15 panes of glass with air pockets in between. Derived from silica, aluminum oxide, or carbon gels using a supercritical drying process - resulting in a composition of almost 99-percent air - aerogels are the world s lightest solid (among 15 other titles they hold in the Guinness World Records), can float indefinitely on water if treated to be

  5. Seasonal thermal storage: Swedish practice, developments and cost projections

    NASA Astrophysics Data System (ADS)

    Margen, P.

    1981-06-01

    The types of heat store being developed in Sweden for seasonal storage of heat are discussed. This type of storage allows summer excess heat from industrial waste heat plants, garbage burning plants and future central solar heat stations to be stored for winter use on district heating networks. Whereas above ground steel or concrete tanks are usually too expensive insulated earth pits, uninsulated rock caverns and deep ground schemes using rock or clay promise to achieve sufficiently low costs to justify storage when supplied with free or cheap summer treat. For all these concepts demonstration plants were or are being built in Sweden.

  6. Ocean thermal energy conversion: Materials issues

    NASA Astrophysics Data System (ADS)

    Darby, J. B., Jr.

    The Ocean thermal Energy Conversion (OTEC) Program, in the Ocean Energy Technology Division of the U.S. Department of Energy, is concerned with the development of options that can be utilized to extract and distribute significant amounts of energy from the ocean. The biofouling control and materials portion of the program is concerned with the development of effective and environmentally acceptable methods to minimize biofouling and corrosion in high thermal conductivity materials suitable for use in heat exchangers and condensers. The mechanical and chemical techniques employed for biofouling control are reviewed and the recent success with chlorination is presented. The corrosion of aluminum alloys, copper alloys, stainless steel, stainless alloys, and titanium in near-surface warm and deep cold water is reviewed with emphasis on aluminum alloys. The major materials issues are reviewed with emphasis on lifetime and cost.

  7. Making `Internal Thermal Energy' Visible

    NASA Astrophysics Data System (ADS)

    Zou, Xueli

    2004-09-01

    In a 1992 paper published in this journal, Uri Ganiel described a pair of model carts used to demonstrate elastic and inelastic collisions. The wooden carts had low-friction wheels and a steel-strip bumper on one end. On one of the carts, a number of brass washers were rigidly mounted in vertical stacks to a wooden framework. The other cart was similar except that the washers were tied to rubber bands that were stretched horizontally and diagonally across the framework. When the first cart was rolled into a wall it bounced off with only a small reduction in speed ("elastic" collision). The second cart, on the other hand, was found to come nearly to a complete stop upon colliding with the wall ("inelastic" collision). Following the instructions given in Ganiel's paper, I built a pair of carts and demonstrated them to introductory-level physics students at a large public university. It was interesting to find that many students were distracted by the different-looking structures of the two model carts.2 They thought the different distributions of washers between the carts resulted in the rubber-band cart bouncing back a significantly shorter distance than the rigid-rod one after they both collided with a wall at the same initial speed. Apparently, the students had difficulties in understanding the collisions and used surface features to reason about them. To avoid this superficial distraction and to help students visualize easily "where the kinetic energy goes in an inelastic collision," I modified the rigid-rod cart to have washers fixed on hollow aluminum rods mounted at four different levels horizontally and diagonally (see Fig. 1). The new pair of the model carts look very similar to each other: They have the same bumpers, same wheels, same distributions of washers, and same masses.

  8. Effects of seasonal and climate variations on calves' thermal comfort and behaviour

    NASA Astrophysics Data System (ADS)

    Tripon, Iulian; Cziszter, Ludovic Toma; Bura, Marian; Sossidou, Evangelia N.

    2014-09-01

    The aim of this study was to measure the effect of season and climate variations on thermal comfort and behaviour of 6-month-old dairy calves housed in a semi-opened shelter to develop animal-based indicators for assessing animal thermal comfort. The ultimate purpose was to further exploit the use of those indicators to prevent thermal stress by providing appropriate care to the animals. Measurements were taken for winter and summer seasons. Results showed that season significantly influenced ( P ≤ 0.01) the lying down behaviour of calves by reducing the time spent lying, from 679.9 min in winter to 554.1 min in summer. Moreover, season had a significant influence ( P ≤ 0.01) on feeding behaviour. In detail, the total length of feeding periods was shorter in winter, 442.1 min in comparison to 543.5 min in summer. Time spent drinking increased significantly ( P ≤ 0.001), from 11.9 min in winter to 26.9 min in summer. Furthermore, season had a significant influence ( P ≤ 0.001) on self grooming behaviour which was 5.5 times longer in duration in winter than in summer (1,336 s vs 244 s). It was concluded that calves' thermal comfort is affected by seasonal and climate variations and that this can be assessed by measuring behaviour with animal-based indicators, such as lying down, resting, standing up, feeding, rumination, drinking and self grooming. The indicators developed may be a useful tool to prevent animal thermal stress by providing appropriate housing and handling to calves under seasonal and climate challenge.

  9. Effects of seasonal and climate variations on calves' thermal comfort and behaviour.

    PubMed

    Tripon, Iulian; Cziszter, Ludovic Toma; Bura, Marian; Sossidou, Evangelia N

    2014-09-01

    The aim of this study was to measure the effect of season and climate variations on thermal comfort and behaviour of 6-month-old dairy calves housed in a semi-opened shelter to develop animal-based indicators for assessing animal thermal comfort. The ultimate purpose was to further exploit the use of those indicators to prevent thermal stress by providing appropriate care to the animals. Measurements were taken for winter and summer seasons. Results showed that season significantly influenced (P ≤ 0.01) the lying down behaviour of calves by reducing the time spent lying, from 679.9 min in winter to 554.1 min in summer. Moreover, season had a significant influence (P ≤ 0.01) on feeding behaviour. In detail, the total length of feeding periods was shorter in winter, 442.1 min in comparison to 543.5 min in summer. Time spent drinking increased significantly (P ≤ 0.001), from 11.9 min in winter to 26.9 min in summer. Furthermore, season had a significant influence (P ≤ 0.001) on self grooming behaviour which was 5.5 times longer in duration in winter than in summer (1,336 s vs 244 s). It was concluded that calves' thermal comfort is affected by seasonal and climate variations and that this can be assessed by measuring behaviour with animal-based indicators, such as lying down, resting, standing up, feeding, rumination, drinking and self grooming. The indicators developed may be a useful tool to prevent animal thermal stress by providing appropriate housing and handling to calves under seasonal and climate challenge.

  10. Phase change thermal energy storage material

    DOEpatents

    Benson, David K.; Burrows, Richard W.

    1987-01-01

    A thermal energy storge composition is disclosed. The composition comprises a non-chloride hydrate having a phase change transition temperature in the range of 70.degree.-95.degree. F. and a latent heat of transformation of at least about 35 calories/gram.

  11. Concrete for Ocean Thermal Energy, Conversion Structures.

    DTIC Science & Technology

    1976-08-01

    construction of massive floating structures to house ocean thermal energy conversion ( OTEC ) systems. The relevant capabilities and limitations of available...which reasonable improvements can be made in the near term to provide greater assurances of long-term safe and reliable operation of the OTEC systems and to provide lower cost structures. (Author)

  12. Alternative biomass sources for thermal energy generation

    NASA Astrophysics Data System (ADS)

    Steensen, Torge; Müller, Sönke; Dresen, Boris; Büscher, Olaf

    2015-04-01

    Traditionally, renewable biomass energy sources comprise forests, agriculture and other large vegetation units. With the increasing demand on those landscape elements, including conflicts of interest to nature conservation and food production, the research focus should also incorporate smaller vegetation entities. In this study, we highlight the availability of small-scale features like roadside vegetation or hedges, which are rarely featured in maps. Roadside vegetation, however, is well known and regularly trimmed to allow the passing of traffic but the cut material is rarely harvested. Here, we combine a remote-sensing-based approach to quantify the seasonal biomass harvests with a GIS-based method to outline optimal transportation routes to, and the location of, storage units and power plants. Our main data source will be ESA's upcoming Sentinel-2 optical satellite. Spatial resolution of 10 meters in the visible and near infrared requires the use of spectral unmixing to derive end member spectra of the targeted biomass objects. Additional stereo-matching and LIDAR measurements allow the accompanying height estimate to derive the biomass volume and its changes over time. GIS data bases from the target areas allow the discrimination between traditional, large features (e.g. forests and agriculture) as well as previously unaccounted for, smaller vegetation units. With the mapped biomass occurrence and additional, GIS-based infrastructure information, we can outline transport routes that take into account local restrictions like nature reserve areas, height or weight limitations as well as transport costs in relation to potential gains. This information can then be processed to outline optimal places for power plants. To simulate the upcoming Sentinel-2 data sets, we use airborne data from the AISA Eagle, spatially and spectrally down-sampled to match Sentinel 2's resolution. Our test scenario is an area in western Germany, the Kirchheller Heide, close to the city

  13. Behavioural Responses to Thermal Conditions Affect Seasonal Mass Change in a Heat-Sensitive Northern Ungulate

    PubMed Central

    van Beest, Floris M.; Milner, Jos M.

    2013-01-01

    Background Empirical tests that link temperature-mediated changes in behaviour (activity and resource selection) to individual fitness or condition are currently lacking for endotherms yet may be critical to understanding the effect of climate change on population dynamics. Moose (Alces alces) are thought to suffer from heat stress in all seasons so provide a good biological model to test whether exposure to non-optimal ambient temperatures influence seasonal changes in body mass. Seasonal mass change is an important fitness correlate of large herbivores and affects reproductive success of female moose. Methodology/Principal Findings Using GPS-collared adult female moose from two populations in southern Norway we quantified individual differences in seasonal activity budget and resource selection patterns as a function of seasonal temperatures thought to induce heat stress in moose. Individual body mass was recorded in early and late winter, and autumn to calculate seasonal mass changes (n = 52 over winter, n = 47 over summer). We found large individual differences in temperature-dependent resource selection patterns as well as within and between season variability in thermoregulatory strategies. As expected, individuals using an optimal strategy, selecting young successional forest (foraging habitat) at low ambient temperatures and mature coniferous forest (thermal shelter) during thermally stressful conditions, lost less mass in winter and gained more mass in summer. Conclusions/Significance This study provides evidence that behavioural responses to temperature have important consequences for seasonal mass change in moose living in the south of their distribution in Norway, and may be a contributing factor to recently observed declines in moose demographic performance. Although the mechanisms that underlie the observed temperature mediated habitat-fitness relationship remain to be tested, physiological state and individual variation in thermal tolerance

  14. Environmental impacts of ocean thermal energy conversion

    SciTech Connect

    Not Available

    1986-04-01

    Ocean thermal energy conversion (OTEC) is a promising technology for production of energy and usable by-products from solar-generated temperature gradients in the world's oceans. Although considered benign compared to alternative forms of energy generation, deployment of OTEC plants will result in interactions with marine, terrestrial, and atmospheric environments and in socioeconomic interactions with surrounding areas. The Ocean Energy Technology Program of the Department of Energy has funded research to improve the understanding of these interactions. No insurmountable environmental obstacle to OTEC deployment has been uncovered. This document contains a summary of that research for entrepreneurs, utility engineers, and others interested in pursuing OTEC's potential. In addition, it provides a guide to permits, regulations, and licenses applicable to construction of an OTEC plant.

  15. Impact of shade on outdoor thermal comfort—a seasonal field study in Tempe, Arizona

    NASA Astrophysics Data System (ADS)

    Middel, Ariane; Selover, Nancy; Hagen, Björn; Chhetri, Nalini

    2016-12-01

    Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade and tree shade on thermal comfort through meteorological observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. During the course of 1 year, on selected clear calm days representative of each season, we conducted hourly meteorological transects from 7:00 a.m. to 6:00 p.m. and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on a semantic differential 9-point scale, increasing thermal comfort in all seasons except winter. Shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shades are equally efficient in hot dry climates. Globe temperature explained 51 % of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors included adaptation, thermal comfort vote, thermal preference, gender, season, and time of day. A regression of subjective thermal sensation on physiological equivalent temperature yielded a neutral temperature of 28.6 °C. The acceptable comfort range was 19.1 °C-38.1 °C with a preferred temperature of 20.8 °C. Respondents exposed to above neutral temperature felt more comfortable if they had been in air-conditioning 5 min prior to the survey, indicating a lagged response to outdoor conditions. Our study highlights the importance of active solar access management in hot urban areas to reduce thermal stress.

  16. Impact of shade on outdoor thermal comfort-a seasonal field study in Tempe, Arizona.

    PubMed

    Middel, Ariane; Selover, Nancy; Hagen, Björn; Chhetri, Nalini

    2016-12-01

    Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade and tree shade on thermal comfort through meteorological observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. During the course of 1 year, on selected clear calm days representative of each season, we conducted hourly meteorological transects from 7:00 a.m. to 6:00 p.m. and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on a semantic differential 9-point scale, increasing thermal comfort in all seasons except winter. Shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shades are equally efficient in hot dry climates. Globe temperature explained 51 % of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors included adaptation, thermal comfort vote, thermal preference, gender, season, and time of day. A regression of subjective thermal sensation on physiological equivalent temperature yielded a neutral temperature of 28.6 °C. The acceptable comfort range was 19.1 °C-38.1 °C with a preferred temperature of 20.8 °C. Respondents exposed to above neutral temperature felt more comfortable if they had been in air-conditioning 5 min prior to the survey, indicating a lagged response to outdoor conditions. Our study highlights the importance of active solar access management in hot urban areas to reduce thermal stress.

  17. Thermal Profiling of Residential Energy Use

    SciTech Connect

    Albert, A; Rajagopal, R

    2015-03-01

    This work describes a methodology for informing targeted demand-response (DR) and marketing programs that focus on the temperature-sensitive part of residential electricity demand. Our methodology uses data that is becoming readily available at utility companies-hourly energy consumption readings collected from "smart" electricity meters, as well as hourly temperature readings. To decompose individual consumption into a thermal-sensitive part and a base load (non-thermally-sensitive), we propose a model of temperature response that is based on thermal regimes, i.e., unobserved decisions of consumers to use their heating or cooling appliances. We use this model to extract useful benchmarks that compose thermal profiles of individual users, i.e., terse characterizations of the statistics of these users' temperature-sensitive consumption. We present example profiles generated using our model on real consumers, and show its performance on a large sample of residential users. This knowledge may, in turn, inform the DR program by allowing scarce operational and marketing budgets to be spent on the right users-those whose influencing will yield highest energy reductions-at the right time. We show that such segmentation and targeting of users may offer savings exceeding 100% of a random strategy.

  18. Aquifer thermal energy storage: a survey

    SciTech Connect

    Tsang, C.F.; Hopkins, D.; Hellstroem, G.

    1980-01-01

    The disparity between energy production and demand in many power plants has led to increased research on the long-term, large-scale storage of thermal energy in aquifers. Field experiments have been conducted in Switzerland, France, the United States, Japan, and the People's Republic of China to study various technical aspects of aquifer storage of both hot and cold water. Furthermore, feasibility studies now in progress include technical, economic, and environmental analyses, regional exploration to locate favorable storage sites, and evaluation and design of pilot plants. Several theoretical and modeling studies are also under way. Among the topics being studied using numerical models are fluid and heat flow, dispersion, land subsidence or uplift, the efficiency of different injection/withdrawal schemes, buoyancy tilting, numerical dispersion, the use of compensation wells to counter regional flow, steam injection, and storage in narrow glacial deposits of high permeability. Experiments to date illustrate the need for further research and development to ensure successful implementation of an aquifer storage system. Some of the areas identified for further research include shape and location of the hydrodynamic and thermal fronts, choice of appropriate aquifers, thermal dispersion, possibility of land subsidence or uplift, thermal pollution, water chemistry, wellbore plugging and heat exchange efficiency, and control of corrosion.

  19. Operational Experience from Solar Thermal Energy Projects

    NASA Technical Reports Server (NTRS)

    Cameron, C. P.

    1984-01-01

    Over the past few years, Sandia National Laboratories were involved in the design, construction, and operation of a number of DOE-sponsored solar thermal energy systems. Among the systems currently in operation are several industrial process heat projects and the Modular Industrial Solar Retrofit qualification test systems, all of which use parabolic troughs, and the Shenandoah Total Energy Project, which uses parabolic dishes. Operational experience has provided insight to both desirable and undesirable features of the designs of these systems. Features of these systems which are also relevant to the design of parabolic concentrator thermal electric systems are discussed. Other design features discussed are system control functions which were found to be especially convenient or effective, such as local concentrator controls, rainwash controls, and system response to changing isolation. Drive systems are also discussed with particular emphasis of the need for reliability and the usefulness of a manual drive capability.

  20. Operational experience from solar thermal energy projects

    NASA Astrophysics Data System (ADS)

    Cameron, C. P.

    1984-03-01

    Over the past few years, Sandia National Laboratories were involved in the design, construction, and operation of a number of DOE-sponsored solar thermal energy systems. Among the systems currently in operation are several industrial process heat projects and the Modular Industrial Solar Retrofit qualification test systems, all of which use parabolic troughs, and the Shenandoah Total Energy Project, which uses parabolic dishes. Operational experience has provided insight to both desirable and undesirable features of the designs of these systems. Features of these systems which are also relevant to the design of parabolic concentrator thermal electric systems are discussed. Other design features discussed are system control functions which were found to be especially convenient or effective, such as local concentrator controls, rainwash controls, and system response to changing isolation. Drive systems are also discussed with particular emphasis of the need for reliability and the usefulness of a manual drive capability.

  1. Solar Thermal Energy Storage Device: Hybrid Nanostructures for High-Energy-Density Solar Thermal Fuels

    SciTech Connect

    2012-01-09

    HEATS Project: MIT is developing a thermal energy storage device that captures energy from the sun; this energy can be stored and released at a later time when it is needed most. Within the device, the absorption of sunlight causes the solar thermal fuel’s photoactive molecules to change shape, which allows energy to be stored within their chemical bonds. A trigger is applied to release the stored energy as heat, where it can be converted into electricity or used directly as heat. The molecules would then revert to their original shape, and can be recharged using sunlight to begin the process anew. MIT’s technology would be 100% renewable, rechargeable like a battery, and emissions-free. Devices using these solar thermal fuels—called Hybrisol—can also be used without a grid infrastructure for applications such as de-icing, heating, cooking, and water purification.

  2. Energy, Power and Thermal Research Overview

    DTIC Science & Technology

    2010-09-01

    Research Overview Rick Fingers, Ph.D. Chief Energy/Power/Thermal Division Propulsion Directorate Air Force Research ... Air Vehicles Sensors AFOSR 5 AFRL People & Facilities • 10 Major R&D Sites across US • 40 Sites World-Wide • $40B Real Property & Capital throughout... AFRL • 5,764 Government Employees – 4570 Air Force Civilian – 1194 Military • 3,844 Onsite Contractors 6 Propulsion Directorate’s Strategic

  3. Analysis of lunar regolith thermal energy storage

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    1991-01-01

    The concept of using lunar regolith as a thermal energy storage medium was evaluated. The concept was examined by mathematically modeling the absorption and transfer of heat by the lunar regolith. Regolith thermal and physical properties were established through various sources as functions of temperature. Two cases were considered: a semi-infinite, constant temperature, cylindrical heat source embedded in a continuum of lunar regolith and a spherically shaped molten zone of lunar regolith set with an initial temperature profile. The cylindrical analysis was performed in order to examine the amount of energy which can be stored in the regolith during the day. At night, the cylinder acted as a perfect insulator. This cycling was performed until a steady state situation was reached in the surrounding regolith. It was determined that a cycling steady state occurs after approximately 15 day/night cycles. Results were obtained for cylinders of various diameters. The spherical molten zone analysis was performed to establish the amount of thermal energy, within the regolith, necessary to maintain some molten material throughout a nighttime period. This surrounding temperature profile was modeled after the cycling steady state temperature profile established by the cylindrical analysis. It was determined that a molten sphere diameter of 4.76 m is needed to maintain a core temperature near the low end of the melting temperature range throughout one nighttime period.

  4. High temperature underground thermal energy storage system for solar energy

    NASA Astrophysics Data System (ADS)

    Collins, R. E.

    1980-08-01

    The activities feasibility of high temperature underground thermal storage of energy was investigated. Results indicate that salt cavern storage of hot oil is both technically and economically feasible as a method of storing huge quantities of heat at relatively low cost. One particular system identified utilizes a gravel filled cavern leached within a salt dome. Thermal losses are shown to be less than one percent of cyclically transferred heat. A system like this having a 40 MW sub t transfer rate capability and over eight hours of storage capacity is shown to cost about $13.50 per KWh sub t.

  5. High temperature underground thermal energy storage system for solar energy

    NASA Technical Reports Server (NTRS)

    Collins, R. E.

    1980-01-01

    The activities feasibility of high temperature underground thermal storage of energy was investigated. Results indicate that salt cavern storage of hot oil is both technically and economically feasible as a method of storing huge quantities of heat at relatively low cost. One particular system identified utilizes a gravel filled cavern leached within a salt dome. Thermal losses are shown to be less than one percent of cyclically transferred heat. A system like this having a 40 MW sub t transfer rate capability and over eight hours of storage capacity is shown to cost about $13.50 per KWh sub t.

  6. Seasonal changes in thermal environment and metabolic enzyme activity in the diamondback terrapin (Malaclemys terrapin).

    PubMed

    Williard, Amanda Southwood; Harden, Leigh Anne

    2011-04-01

    Diamondback terrapins experience broad fluctuations in temperature on both a daily and seasonal basis in their estuarine environment. We measured metabolic enzyme activity in terrapin muscle tissue to assess thermal dependence and the role of temperature in seasonal metabolic downregulation in this species. Activity of lactate dehydrogenase (LDH), pyruvate kinase (PK), citrate synthase (CS), and cytochrome c oxidase (CCO) was assayed at 10, 20, 30, and 40 °C for tissue collected during summer and winter. The Q(10) for enzyme activity varied between 1.31 and 2.11 within the temperature range at which terrapins were active (20-40 °C). The Q(10) for LDH, CS, and CCO varied between 1.39 and 1.76 and between 10 and 20 °C, but PK exhibited heightened thermal sensitivity within this lower temperature range, with a Q(10) of 2.90 for summer-collected tissue and 5.55 for winter-collected tissue. There was no significant effect of season on activity of LDH or PK, but activity of CS and CCO was significantly lower in winter-collected tissue compared with summer-collected tissue. Results indicate that temperature effects contribute to seasonal metabolic downregulation and dormancy in terrapins, but other environmental factors (i.e. oxygen availability), as well as seasonal shifts in blood biochemistry and circulating hormones may also play an important role.

  7. Thermal stress depletes energy reserves in Drosophila

    PubMed Central

    Klepsatel, Peter; Gáliková, Martina; Xu, Yanjun; Kühnlein, Ronald P.

    2016-01-01

    Understanding how environmental temperature affects metabolic and physiological functions is of crucial importance to assess the impacts of climate change on organisms. Here, we used different laboratory strains and a wild-caught population of the fruit fly Drosophila melanogaster to examine the effect of temperature on the body energy reserves of an ectothermic organism. We found that permanent ambient temperature elevation or transient thermal stress causes significant depletion of body fat stores. Surprisingly, transient thermal stress induces a lasting “memory effect” on body fat storage, which also reduces survivorship of the flies upon food deprivation later after stress exposure. Functional analyses revealed that an intact heat-shock response is essential to protect flies from temperature-dependent body fat decline. Moreover, we found that the temperature-dependent body fat reduction is caused at least in part by apoptosis of fat body cells, which might irreversibly compromise the fat storage capacity of the flies. Altogether, our results provide evidence that thermal stress has a significant negative impact on organismal energy reserves, which in turn might affect individual fitness. PMID:27641694

  8. Thermal stress depletes energy reserves in Drosophila.

    PubMed

    Klepsatel, Peter; Gáliková, Martina; Xu, Yanjun; Kühnlein, Ronald P

    2016-09-19

    Understanding how environmental temperature affects metabolic and physiological functions is of crucial importance to assess the impacts of climate change on organisms. Here, we used different laboratory strains and a wild-caught population of the fruit fly Drosophila melanogaster to examine the effect of temperature on the body energy reserves of an ectothermic organism. We found that permanent ambient temperature elevation or transient thermal stress causes significant depletion of body fat stores. Surprisingly, transient thermal stress induces a lasting "memory effect" on body fat storage, which also reduces survivorship of the flies upon food deprivation later after stress exposure. Functional analyses revealed that an intact heat-shock response is essential to protect flies from temperature-dependent body fat decline. Moreover, we found that the temperature-dependent body fat reduction is caused at least in part by apoptosis of fat body cells, which might irreversibly compromise the fat storage capacity of the flies. Altogether, our results provide evidence that thermal stress has a significant negative impact on organismal energy reserves, which in turn might affect individual fitness.

  9. Training migrant and seasonal farmworkers for energy-related occupations

    SciTech Connect

    Weseman, M.

    1980-07-01

    The US Department of Energy (DOE) and US Department of Labor (DOL) have cosponsored a number of demonstration programs to train economically disadvantaged migrant and seasonal farmworkers for energy-related technical and skilled occupations. This descriptive study examines the first DOE/DOL demonstration to determine the impact of training on participants' subsequent labor-force activity and the effectiveness of the program in meeting the needs of this target group. Analysis of participants' employment and wage rates before and after training indicates favorable outcomes as wages and the number employed increased significantly. All selected subgroups experienced substantial employment-status gains with women reporting the largest increases. Post-training wages of all subgroups were approximately double those before training with women, nonwhites, and high-school graduates reporting the largest increases. Data on farmworkers were compared to those of other clients enrolled in the same program under the Comprehensive Employment and Training Act (CETA), and a national sample of CETA participants enrolled in vocational-training programs. In general, the farmworkers reported employment-status gains similar to the national CETA sample but lower than the other CETA participants enrolled in the same program. The farmworkers' wage gains were significantly greater than those reported by the two comparison groups. Apparent key factors contributing to the success of the program include the farmworkers' desire to leave agricultural labor, their willingness to relocate to accept employment, the existing network of employers developed by the training program, and the program's ability to provide needed supportive services.

  10. Maximizing Thermal Efficiency and Optimizing Energy Management (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    Researchers at the Thermal Test Facility (TTF) on the campus of the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado, are addressing maximizing thermal efficiency and optimizing energy management through analysis of efficient heating, ventilating, and air conditioning (HVAC) strategies, automated home energy management (AHEM), and energy storage systems.

  11. Attenuation of Scattered Thermal Energy Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce a.; Seroka, Katelyn T.; McPhate, Jason B.; Miller, Sharon K.

    2011-01-01

    The attenuation of scattered thermal energy atomic oxygen is relevant to the potential damage that can occur within a spacecraft which sweeps through atomic oxygen in low Earth orbit (LEO). Although there can be significant oxidation and resulting degradation of polymers and some metals on the external surfaces of spacecraft, there are often openings on a spacecraft such as telescope apertures, vents, and microwave cavities that can allow atomic oxygen to enter and scatter internally to the spacecraft. Atomic oxygen that enters a spacecraft can thermally accommodate and scatter to ultimately react or recombine on surfaces. The atomic oxygen that does enter a spacecraft can be scavenged by use of high erosion yield polymers to reduce its reaction on critical surfaces and materials. Polyoxymethylene and polyethylene can be used as effective atomic oxygen scavenging polymers.

  12. OCEAN THERMAL ENERGY CONVERSION PROGRAMMATIC ENVIRONMENTAL ASSESSMENT

    SciTech Connect

    Sands, M. Dale

    1980-08-01

    Significant achievements in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power in this decade with subsequent large-scale commercialization to follow by the turn of the century. Under U.S. Department of Energy funding, Interstate Electronics has prepared an OTEC Programmatic Environmental Assessment (EA) that considers tne development, demonstration, and commercialization of OTEC power systems. The EA considers several tecnnological designs (open cycle and closed cycle), plant configurations (land-based, moored, and plantship), and power usages (baseload electricity and production of ammonia and aluminum). Potencial environmental impacts, health and safety issues, and a status update of international, federal, and state plans and policies, as they may influence OTEC deployments, are included.

  13. Seasonal variability of eddy kinetic energy in the North Atlantic subtropical gyre: A high-resolution ocean model analysis

    NASA Astrophysics Data System (ADS)

    Rieck, Jan Klaus; Böning, Claus W.; Greatbatch, Richard J.; Scheinert, Markus

    2016-04-01

    A global ocean model with 1/12° horizontal resolution is used to assess the seasonal cycle of surface eddy kinetic energy (EKE) in the North Atlantic. The model reproduces the salient features of the observed mean surface EKE, including amplitude and phase of its seasonal cycle in most parts of the basin. In the interior North Atlantic subtropical gyre, EKE peaks in summer down to a depth of ˜200 m, below which the seasonal cycle is weak. Investigation of the possible driving mechanisms reveals the seasonal changes in the thermal interactions with the atmosphere to be the most likely cause of the summer maximum of EKE. The development of the seasonal thermocline in spring and summer is accompanied by stronger mesoscale variations in the horizontal temperature gradients near the surface which corresponds, by thermal wind balance, to an intensification of mesoscale velocity anomalies toward the surface. An extension of the analysis leads to similar results in the South Atlantic, North Pacific and South Pacific subtropical gyres.

  14. Ocean thermal energy conversion: Perspective and status

    SciTech Connect

    Thomas, A.; Hillis, D.L.

    1990-01-01

    The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully be George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250--400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore-based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed-cycle concept. Cost-effective heat-exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat-transfer augmentation techniques were identified, which promised a reduction on heat-exchanger size and cost. Fresh water was produced by an OTEC open-cycle flash evaporator, using the heat energy in the seawater itself. The current R D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open-cycle process. The 10 MW shore-based, closed-cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power -- both valuable commodities on many tropical islands. The open-cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources. 7 refs.

  15. Ocean thermal energy conversion: Perspective and status

    NASA Astrophysics Data System (ADS)

    Thomas, Anthony; Hillis, David L.

    The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully by George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250 to 400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed cycle concept. Cost effective heat exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat transfer augmentation techniques were identified, which promised a reduction on heat exchanger size and cost. Fresh water was produced by an OTEC open cycle flash evaporator, using the heat energy in the seawater itself. The current R and D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open cycle process. The 10 MW shore-based, closed cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power; both valuable commodities on many tropical islands. The open cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources.

  16. Solar energy system performance evaluation: Seasonal report for Decade 80 House, Tucson, Arizona

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The operational and thermal performance of the Decade 80 solar energy system is described. The system was designed by Cooper Development Association, Inc. with space heating and space cooling to a one-story, single family residence located in Tucson, Arizona. The Decade 80 House was designed and built in the mid-70's to be a showplace/workshop for solar energy utilization. Superior construction techniques, the use of quality materials and a full time maintenance staff have served to make the entire system an outstanding example of the application of solar energy for residential purposes. The luxury of a full time, on-site maintenance person is perhaps the single most important aspect of this program. While most installations cannot support this level of maintenance, it was very useful in keeping all subsystems operating in top form and allowing for a full season data collection to be obtained. Several conclusions were drawn from the long term monitoring effort, among which are: (1) flat plate collectors will support cooling; (2) definite energy savings can be realized; and (3) more frequent periodic maintenance may be required on solar energy systems that are not custom built.

  17. Commercialization of aquifer thermal energy storage technology

    SciTech Connect

    Hattrup, M.P.; Weijo, R.O.

    1989-09-01

    Pacific Northwest Laboratory (PNL) conducted this study for the US Department of Energy's (DOE) Office of Energy Storage and Distribution. The purpose of the study was to develop and screen a list of potential entry market applications for aquifer thermal energy storage (ATES). Several initial screening criteria were used to identify promising ATES applications. These include the existence of an energy availability/usage mismatch, the existence of many similar applications or commercial sites, the ability to utilize proven technology, the type of location, market characteristics, the size of and access to capital investment, and the number of decision makers involved. The in-depth analysis identified several additional screening criteria to consider in the selection of an entry market application. This analysis revealed that the best initial applications for ATES are those where reliability is acceptable, and relatively high temperatures are allowable. Although chill storage was the primary focus of this study, applications that are good candidates for heat ATES were also of special interest. 11 refs., 3 tabs.

  18. Seasonal thermal ecology of adult walleye (Sander vitreus) in Lake Huron and Lake Erie

    USGS Publications Warehouse

    Peat, Tyler B; Hayden, Todd A.; Gutowsky, Lee F G; Vandergoot, Christopher S.; Fielder, David G.; Madenjian, Charles P.; Murchie, Karen J; Dettmers, John M.; Krueger, Charles C.; Cooke, Steven J.

    2015-01-01

    The purpose of this study was to characterize thermal patterns and generate occupancy models for adult walleye from lakes Erie and Huron with internally implanted biologgers coupled with a telemetry study to assess the effects of sex, fish size, diel periods, and lake. Sex, size, and diel periods had no effect on thermal occupancy of adult walleye in either lake. Thermal occupancy differed between lakes and seasons. Walleye from Lake Erie generally experienced higher temperatures throughout the spring and summer months than did walleye in Lake Huron, due to limnological differences between the lakes. Tagged walleye that remained in Saginaw Bay, Lake Huron (i.e., adjacent to the release location), as opposed to those migrating to the main basin of Lake Huron, experienced higher temperatures, and thus accumulated more thermal units (the amount of temperature units amassed over time) throughout the year. Walleye that migrated toward the southern end of Lake Huron occupied higher temperatures than those that moved toward the north. Consequently, walleye that emigrated from Saginaw Bay experienced thermal environments that were more favorable for growth as they spent more time within their thermal optimas than those that remained in Saginaw Bay. Results presented in this paper provide information on the thermal experience of wild fish in a large lake, and could be used to refine sex- and lake-specific bioenergetics models of walleye in the Great Lakes to enable the testing of ecological hypotheses.

  19. Seasonal thermal ecology of adult walleye (Sander vitreus) in Lake Huron and Lake Erie.

    PubMed

    Peat, Tyler B; Hayden, Todd A; Gutowsky, Lee F G; Vandergoot, Christopher S; Fielder, David G; Madenjian, Charles P; Murchie, Karen J; Dettmers, John M; Krueger, Charles C; Cooke, Steven J

    2015-10-01

    The purpose of this study was to characterize thermal patterns and generate occupancy models for adult walleye from lakes Erie and Huron with internally implanted biologgers coupled with a telemetry study to assess the effects of sex, fish size, diel periods, and lake. Sex, size, and diel periods had no effect on thermal occupancy of adult walleye in either lake. Thermal occupancy differed between lakes and seasons. Walleye from Lake Erie generally experienced higher temperatures throughout the spring and summer months than did walleye in Lake Huron, due to limnological differences between the lakes. Tagged walleye that remained in Saginaw Bay, Lake Huron (i.e., adjacent to the release location), as opposed to those migrating to the main basin of Lake Huron, experienced higher temperatures, and thus accumulated more thermal units (the amount of temperature units amassed over time) throughout the year. Walleye that migrated toward the southern end of Lake Huron occupied higher temperatures than those that moved toward the north. Consequently, walleye that emigrated from Saginaw Bay experienced thermal environments that were more favorable for growth as they spent more time within their thermal optimas than those that remained in Saginaw Bay. Results presented in this paper provide information on the thermal experience of wild fish in a large lake, and could be used to refine sex- and lake-specific bioenergetics models of walleye in the Great Lakes to enable the testing of ecological hypotheses.

  20. District Energy Corporation SW 40th Street Thermal Energy Plant

    SciTech Connect

    Davlin, Thomas

    2014-06-06

    The overall deliverable from the project is the design, construction and commissioning of a detention facility heating and cooling system that minimizes ownership costs and maximizes efficiency (and therefore minimizes environmental impact). The primary deliverables were the proof of concept for the application of geothermal systems for an institutional facility and the ongoing, quarterly system operating data downloads to the Department of Energy . The primary advantage of geothermal based heat pump systems is the higher efficiency of the system compared to a conventional chiller, boiler, cooling tower based system. The higher efficiency results in a smaller environmental foot print and lower energy costs for the detention facility owner, Lancaster County. The higher efficiency for building cooling is primarily due to a more constant compressor condensing temperature with the geothermal well field acting as a thermal “sink” (in place of the conventional system’s cooling tower). In the heating mode, Ground Couple Heat Pump (GCHP) systems benefits from the advantage of a heat pump Coefficient of Performance (COP) of approximately 3.6, significantly better than a conventional gas boiler. The geothermal well field acting as a thermal “source” allows the heat pumps to operate efficiently in the heating mode regardless of ambient temperatures. The well field is partially located in a wetland with a high water table so, over time, the project will be able to identify the thermal loading characteristics of a well field located in a high water table location. The project demonstrated how a large geothermal well field can be installed in a wetland area in an economical and environmentally sound manner. Finally, the SW 40th Street Thermal Energy Plant project demonstrates the benefits of providing domestic hot water energy, as well as space heating, to help balance well filed thermal loading in a cooling dominated application. During the period of August 2012 thru

  1. Development of thermal energy storage units for spacecraft cryogenic coolers

    NASA Technical Reports Server (NTRS)

    Richter, R.; Mahefkey, E. T.

    1980-01-01

    Thermal Energy Storage Units were developed for storing thermal energy required for operating Vuilleumier cryogenic space coolers. In the course of the development work the thermal characteristics of thermal energy storage material was investigated. By three distinctly different methods it was established that ternary salts did not release fusion energy as determined by ideality at the melting point of the eutectic salt. Phase change energy was released over a relatively wide range of temperature with a large change in volume. This strongly affects the amount of thermal energy that is available to the Vuilleumier cryogenic cooler at its operating temperature range and the amount of thermal energy that can be stored and released during a single storage cycle.

  2. MEMS based pyroelectric thermal energy harvester

    DOEpatents

    Hunter, Scott R; Datskos, Panagiotis G

    2013-08-27

    A pyroelectric thermal energy harvesting apparatus for generating an electric current includes a cantilevered layered pyroelectric capacitor extending between a first surface and a second surface, where the first surface includes a temperature difference from the second surface. The layered pyroelectric capacitor includes a conductive, bimetal top electrode layer, an intermediate pyroelectric dielectric layer and a conductive bottom electrode layer. In addition, a pair of proof masses is affixed at a distal end of the layered pyroelectric capacitor to face the first surface and the second surface, wherein the proof masses oscillate between the first surface and the second surface such that a pyroelectric current is generated in the pyroelectric capacitor due to temperature cycling when the proof masses alternately contact the first surface and the second surface.

  3. Ocean Thermal Energy Conversion Act of 1980

    SciTech Connect

    Not Available

    1980-01-01

    A legislative proposal to develop ocean thermal energy conversion (OTEC) facilities for power generation was the subject of hearings held on April 10 and May 1, 1980. Following the test of S. 2492 are the statements of 20 witnesses and additional materials submitted for consideration. The need for a large-scale demonstration of OTEC and the need for a Federal regulatory, siting, and financial-assistance framework are the major commercialization issues. S. 2492 provides one-stop licensing by treating the facilities as vessels and making them eligible for loan guarantees. The bill complements S. 1430, which deals with the demonstration program. OTEC development in Hawaii has progressed to a second pilot project. (DCK)

  4. Seasonal and latitudinal acclimatization of cardiac transcriptome responses to thermal stress in porcelain crabs, Petrolisthes cinctipes.

    PubMed

    Stillman, Jonathon H; Tagmount, Abderrahmane

    2009-10-01

    Central predictions of climate warming models include increased climate variability and increased severity of heat waves. Physiological acclimatization in populations across large-scale ecological gradients in habitat temperature fluctuation is an important factor to consider in detecting responses to climate change related increases in thermal fluctuation. We measured in vivo cardiac thermal maxima and used microarrays to profile transcriptome heat and cold stress responses in cardiac tissue of intertidal zone porcelain crabs across biogeographic and seasonal gradients in habitat temperature fluctuation. We observed acclimatization dependent induction of heat shock proteins, as well as unknown genes with heat shock protein-like expression profiles. Thermal acclimatization had the largest effect on heat stress responses of extensin-like, beta tubulin, and unknown genes. For these genes, crabs acclimatized to thermally variable sites had higher constitutive expression than specimens from low variability sites, but heat stress dramatically induced expression in specimens from low variability sites and repressed expression in specimens from highly variable sites. Our application of ecological transcriptomics has yielded new biomarkers that may represent sensitive indicators of acclimatization to habitat temperature fluctuation. Our study also has identified novel genes whose further description may yield novel understanding of cellular responses to thermal acclimatization or thermal stress.

  5. Development of MEMS based pyroelectric thermal energy harvesters

    SciTech Connect

    Hunter, Scott Robert; Lavrik, Nickolay V; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slobodan; Datskos, Panos G

    2011-01-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  6. Development of MEMS based pyroelectric thermal energy harvesters

    NASA Astrophysics Data System (ADS)

    Hunter, Scott R.; Lavrik, Nickolay V.; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

    2011-06-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  7. Advanced Thermal Energy Storage: Novel Tuning of Critical Fluctuations for Advanced Thermal Energy Storage

    SciTech Connect

    2011-12-01

    HEATS Project: NAVITASMAX is developing a novel thermal energy storage solution. This innovative technology is based on simple and complex supercritical fluids— substances where distinct liquid and gas phases do not exist, and tuning the properties of these fluid systems to increase their ability to store more heat. In solar thermal storage systems, heat can be stored in NAVITASMAX’s system during the day and released at night—when the sun is not shining—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in NAVITASMAX’s system at night and released to produce electricity during daytime peak-demand hours.

  8. Seasonal changes in thermal responses of urban residents to cold exposure.

    PubMed

    Mäkinen, Tiina M; Pääkkönen, Tiina; Palinkas, Lawrence A; Rintamäki, Hannu; Leppäluoto, Juhani; Hassi, Juhani

    2004-10-01

    To determine whether urban circumpolar residents show seasonal acclimatisation to cold, thermoregulatory responses and thermal perception during cold exposure were examined in young men during January-March (n=7) and August-September (n=8). Subjects were exposed for 24 h to 22 and to 10 degrees C. Rectal (T(rect)) and skin temperatures were measured throughout the exposure. Oxygen consumption (VO(2)), finger skin blood flow (Q(f)), shivering and cold (CDT) and warm detection thresholds (WDT) were assessed four times during the exposure. Ratings of thermal sensations, comfort and tolerance were recorded using subjective judgement scales at 1-h intervals. During winter, subjects had a significantly higher mean skin temperature at both 22 and 10 degrees C compared with summer. However, skin temperatures decreased more at 10 degrees C in winter and remained higher only in the trunk. Finger skin temperature was higher at 22 degrees C, but lower at 10 degrees C in the winter suggesting an enhanced cold-induced vasoconstriction. Similarly, Q(f) decreased more in winter. The cold detection threshold of the hand was shifted to a lower level in the cold, and more substantially in the winter, which was related to lower skin temperatures in winter. Thermal sensations showed only slight seasonal variation. The observed seasonal differences in thermal responses suggest increased preservation of heat especially in the peripheral areas in winter. Blunted vasomotor and skin temperature responses, which are typical for habituation to cold, were not observed in winter. Instead, the responses in winter resemble aggravated reactions of non-cold acclimatised subjects.

  9. Heat pipe solar receiver with thermal energy storage

    NASA Technical Reports Server (NTRS)

    Zimmerman, W. F.

    1981-01-01

    An HPSR Stirling engine generator system featuring latent heat thermal energy storge, excellent thermal stability and self regulating, effective thermal transport at low system delta T is described. The system was supported by component technology testing of heat pipes and of thermal storage and energy transport models which define the expected performance of the system. Preliminary and detailed design efforts were completed and manufacturing of HPSR components has begun.

  10. Seasonal variation of radiance variances from satellite observations Implication of seasonal variation of available potential energy in the stratosphere

    NASA Technical Reports Server (NTRS)

    Chen, T.-C.; Stanford, J. L.

    1980-01-01

    Nimbus 5 satellite radiances for the period 1973-74 are used to examine the seasonal variation of available potential energy in the stratosphere in order to provide a further observational basis for a long-term numerical simulation of stratospheric circulation. The maximum value of stratospheric zonal available potential energy, A(Z), in the upper and middle stratosphere shows pronounced variations between winter and summer, while little variation occurs in the lower stratospheric A(Z). The aperiodic occurrence of sudden warmings complicates the seasonal variation of A(Z) and A(E) (eddy available potential energy) in the stratosphere, making the energetics irregular. Time-Fourier analysis reveals that the primary variation of A(Z) and A(E) in the stratosphere is annual and semiannual, respectively.

  11. Modulation of photosynthetic energy conversion efficiency in nature: from seconds to seasons.

    PubMed

    Demmig-Adams, Barbara; Cohu, Christopher M; Muller, Onno; Adams, William W

    2012-09-01

    Modulation of the efficiency with which leaves convert absorbed light to photochemical energy [intrinsic efficiency of open photosystem II (PSII) centers, as the ratio of variable to maximal chlorophyll fluorescence] as well as leaf xanthophyll composition (interconversions of the xanthophyll cycle pigments violaxanthin and zeaxanthin) were characterized throughout single days and nights to entire seasons in plants growing naturally in contrasting light and temperature environments. All pronounced decreases of intrinsic PSII efficiency took place in the presence of zeaxanthin. The reversibility of these PSII efficiency changes varied widely, ranging from reversible-within-seconds (in a vine experiencing multiple sunflecks under a eucalypt canopy) to apparently permanently locked-in for entire seasons (throughout the whole winter in a subalpine conifer forest at 3,000 m). While close association between low intrinsic PSII efficiency and zeaxanthin accumulation was ubiquitous, accompanying features (such as trans-thylakoid pH gradient, thylakoid protein composition, and phosphorylation) differed among contrasting conditions. The strongest and longest-lasting depressions in intrinsic PSII efficiency were seen in the most stress-tolerant species. Evergreens, in particular, showed the most pronounced modulation of PSII efficiency and thermal dissipation, and are therefore suggested as model species for the study of photoprotection. Implications of the responses of field-grown plants in nature for mechanistic models are discussed.

  12. Effects of thermal vapor diffusion on seasonal dynamics of water in the unsaturated zone

    USGS Publications Warehouse

    Milly, P.C.D.

    1996-01-01

    The response of water in the unsaturated zone to seasonal changes of temperature (T) is determined analytically using the theory of nonisothermal water transport in porous media, and the solutions are tested against field observations of moisture potential and bomb fallout isotopic (36Cl and3H) concentrations. Seasonally varying land surface temperatures and the resulting subsurface temperature gradients induce thermal vapor diffusion. The annual mean vertical temperature gradient is close to zero: however, the annual mean thermal vapor flux is downward, because the temperature-dependent vapor diffusion coefficient is larger, on average, during downward diffusion (occurring at high T) than during upward diffusion (low T). The annual mean thermal vapor flux is shown to decay exponentially with depth; the depth (about 1 m) at which it decays to ??-1 of its surface value is one half of the corresponding decay depth for the amplitude of seasonal temperature changes. This depth-dependent annual mean flux is effectively a source of water, which must be balanced by a flux divergence associated with other transport processes. In a relatively humid environment the liquid fluxes greatly exceed the thermal vapor fluxes, so such a balance is readily achieved without measurable effect on the dynamics of water in the unsaturated zone. However, if the mean vertical water flux through the unsaturated zone is very small (<1 mm y-1), as it may be at many locations in a desert landscape, the thermal vapor flux must be balanced mostly by a matric-potential-induced upward flux of water. This return flux may include both vapor and liquid components. Below any near-surface zone of weather- related fluctuations of matric potential, maintenance of this upward flux requires an increase with depth in the annual mean matric potential; this theoretical prediction is supported by long-term field measurements in the Chihuahuan Desert. The analysis also makes predictions, confirmed by the field

  13. Seasonality of reproductive events and early mortality in a colony of hamadryas baboons (Papio hamadryas hamadryas) over a 30-year period: Capital breeding and life history patterns in a food-provisioned population seasonally thermally stressed.

    PubMed

    Polo, Pablo; Colmenares, Fernando

    2016-11-01

    In environments where energy demands and resource availability vary seasonally, individuals are expected to time the optimal allocation of resources to support survival and reproduction. Although female baboons are regarded as all year round, capital breeders, we wondered how they would respond in an ecological scenario where food were not limiting, foraging effort were negligible, and they were thermally stressed during the cold winter. This study analyzes a 30-year database of conceptions, births, resumptions of postlactational ovarian activity, menarches, and prenatal and early postnatal reproductive failures recorded in a food-provisioned colony of hamadryas baboons located in a temperate zone (40°25'N) to search for seasonal patterns in their life-history patterns and explore its fitness consequences. The results show that the study females exhibited moderate seasonality and behaved like capital breeders; ovarian activity peaked during the period of benign weather conditions (spring and early summer) and births and lactation peaked during the period when they were thermally stressed and faced a negative energy balance (winter). Mistimed conceptions were more likely to fail than timed conceptions were, although this association could be artefactual due to the difficulty to accurately detect prenatal losses. Insolation and, to a lesser extent, temperature were positively associated with conceptions, resumptions of postlactational ovarian activity and onsets of menarche, and negatively associated with births. These findings highlight the extent of plasticity (width of peaks) and resiliency (retention of a capital breeding tactic even under highly seasonally thermally stressful cold conditions) in how primates can adjust their life history patterns and solve tradeoffs in a scenario of strong seasonal variation. Am. J. Primatol. 78:1149-1164, 2016. © 2016 Wiley Periodicals, Inc.

  14. Hot Thermal Storage in a Variable Power, Renewable Energy System

    DTIC Science & Technology

    2014-06-01

    characteristics and may not necessarily be available in all cases. Types of direct heat energy systems include solar thermal, waste heat , and geothermal ...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) This thesis outlines the design of a renewable energy heat generation system with thermal...LEFT BLANK v ABSTRACT This thesis outlines the design of a renewable energy heat generation system with thermal storage for DOD facilities. The

  15. Changes in energy availability across the season in Division I female soccer players.

    PubMed

    Reed, Jennifer L; De Souza, Mary Jane; Williams, Nancy I

    2013-01-01

    Low energy availability [(energy intake--exercise expenditure)/kg lean body mass], a component of the Female Athlete Triad, has been associated with menstrual disturbances and low bone mass. No studies have examined the energy availability of athletes across a season. The purpose of this study was to assess the prevalence of, and what contributes to, low energy availability in Division I female soccer players across a season. Nineteen participants aged 18-21 years (mean [Vdot]O(2max): 57.0 ± 1.0 mL · kg(-1) · min(-1)) were studied during the pre, mid, and post season. Mean energy availability was overall lowest at mid season, and lower at mid than post season (35.2 ± 3.7 vs. 44.5 ± 3.7 kcal · kg(-1) lean body mass, P = 0.009). Low energy availability (<30 kcal · kg(-1) lean body mass) was observed in 5/19 (26.3%), 5/15 (33.3%), and 2/17 (11.8%) of participants during the pre, mid, and post season. Dietary energy intake was lower mid (P = 0.008) and post season (P = 0.022) than it was pre season (pre: 2794 ± 233 kcal · day(-1); mid: 2208 ± 156 kcal · day(-1); post: 2161 ± 143 kcal · day(-1)). Exercise energy expenditure decreased significantly (P ≤ 0.001) over time (pre: 819 ± 57 kcal · day(-1); mid: 642 ± 26 kcal · day(-1); post: 159 ± 28 kcal · day(-1)). Low energy availability was due to lower dietary energy intake at lunch during pre season (P = 0.014) and during lunch and dinner during mid season (P ≤ 0.030). Energy availability was inversely related to body dissatisfaction (r = -0.62, P = 0.017) and drive for thinness (r = -0.55, P = 0.041) during mid season. Although most Division I female soccer players are not at risk for low energy availability, a concerning proportion exhibited low energy availability at pre or mid season. Further studies are needed to explore strategies to prevent and monitor low energy availability in these athletes.

  16. Seasonal differences in thermal sensation in the outdoor urban environment of Mediterranean climates - the example of Athens, Greece

    NASA Astrophysics Data System (ADS)

    Tseliou, Areti; Tsiros, Ioannis X.; Nikolopoulou, Marialena

    2017-01-01

    Outdoor urban areas are very important for cities and microclimate is a critical parameter in the design process, contributing to thermal comfort which is important for urban developments. The research presented in this paper is part of extensive field surveys conducted in Athens aimed at investigating people's thermal sensation in a Mediterranean city. Based on 2313 questionnaires and microclimatic data the current work focuses on the relative frequencies of people's evaluation of the thermal along with the sun and wind sensations between two seasons trying to identify the seasonal differences in thermal sensation. The impact of basic meteorological factors on thermal discomfort with respect to season are also examined, as well as the use of the outdoor environment. Results show that psychological adaptation is an important contributing factor influencing perception of the thermal environment between seasons. In addition, the thermal sensation votes during the cool months show that individuals are satisfied to a great extend with the thermal environment whereas the combination of high air temperature, strong solar radiation and weak wind lead to thermal discomfort during summertime. As far as the appropriate urban design in the Mediterranean climate is concerned, priority should be given to the warm months of the year.

  17. Seasonal differences in thermal sensation in the outdoor urban environment of Mediterranean climates - the example of Athens, Greece.

    PubMed

    Tseliou, Areti; Tsiros, Ioannis X; Nikolopoulou, Marialena

    2017-01-19

    Outdoor urban areas are very important for cities and microclimate is a critical parameter in the design process, contributing to thermal comfort which is important for urban developments. The research presented in this paper is part of extensive field surveys conducted in Athens aimed at investigating people's thermal sensation in a Mediterranean city. Based on 2313 questionnaires and microclimatic data the current work focuses on the relative frequencies of people's evaluation of the thermal along with the sun and wind sensations between two seasons trying to identify the seasonal differences in thermal sensation. The impact of basic meteorological factors on thermal discomfort with respect to season are also examined, as well as the use of the outdoor environment. Results show that psychological adaptation is an important contributing factor influencing perception of the thermal environment between seasons. In addition, the thermal sensation votes during the cool months show that individuals are satisfied to a great extend with the thermal environment whereas the combination of high air temperature, strong solar radiation and weak wind lead to thermal discomfort during summertime. As far as the appropriate urban design in the Mediterranean climate is concerned, priority should be given to the warm months of the year.

  18. Nonimaging concentrators for solar thermal energy. Final report

    SciTech Connect

    Winston, R.

    1980-03-21

    A small experimental solar collector test facility has been established on the campus of the University of Chicago. This capability has been used to explore applications of nonimaging optics for solar thermal concentration in three substantially different configurations: (1) a single stage system with moderate concentration on an evacuated absorber (a 5.25X evacuated tube Compound Parabolic Concentrator or CPC), (2) a two stage system with high concentration and a non-evacuated absorber (a 16X Fresnel lens/CPC type mirror) and (3) moderate concentration single stage systems with non-evacuated absorbers for lower temperature (a 3X and a 6.5X CPC). Prototypes of each of these systems have been designed, built and tested. The performance characteristics are presented. In addition a 73 m/sup 2/ experimental array of 3X non-evacuated CPC's has been installed in a school heating system on the Navajo Indian Reservation in New Mexico. The full array has a peak noon time efficiency of approx. 50% at ..delta..T = 50/sup 0/C above ambient and has supplied about half the school's heat load for the past two heating seasons. Several theoretical features of nonimaging concentration have been investigated including their long term energy collecting behavior. The measured performance of the different systems shows clearly that non-tracking concentrators can provide solar thermal energy from moderately high low temperature regimes (> 50/sup 0/C above ambient) up into the mid-temperature region (well above 200/sup 0/C above ambient). The measured efficiency at 220/sup 0/C for the 5.25X CPC was as high or higher than that for any of the commercial tracking systems tested.

  19. Crop water stress maps for an entire growing season from visible and thermal UAV imagery

    NASA Astrophysics Data System (ADS)

    Hoffmann, Helene; Jensen, Rasmus; Thomsen, Anton; Nieto, Hector; Rasmussen, Jesper; Friborg, Thomas

    2016-12-01

    This study investigates whether a water deficit index (WDI) based on imagery from unmanned aerial vehicles (UAVs) can provide accurate crop water stress maps at different growth stages of barley and in differing weather situations. Data from both the early and late growing season are included to investigate whether the WDI has the unique potential to be applicable both when the land surface is partly composed of bare soil and when crops on the land surface are senescing. The WDI differs from the more commonly applied crop water stress index (CWSI) in that it uses both a spectral vegetation index (VI), to determine the degree of surface greenness, and the composite land surface temperature (LST) (not solely canopy temperature).Lightweight thermal and RGB (red-green-blue) cameras were mounted on a UAV on three occasions during the growing season 2014, and provided composite LST and color images, respectively. From the LST, maps of surface-air temperature differences were computed. From the color images, the normalized green-red difference index (NGRDI), constituting the indicator of surface greenness, was computed. Advantages of the WDI as an irrigation map, as compared with simpler maps of the surface-air temperature difference, are discussed, and the suitability of the NGRDI is assessed. Final WDI maps had a spatial resolution of 0.25 m.It was found that the UAV-based WDI is in agreement with measured stress values from an eddy covariance system. Further, the WDI is especially valuable in the late growing season because at this stage the remote sensing data represent crop water availability to a greater extent than they do in the early growing season, and because the WDI accounts for areas of ripe crops that no longer have the same need for irrigation. WDI maps can potentially serve as water stress maps, showing the farmer where irrigation is needed to ensure healthy growing plants, during entire growing season.

  20. Mathematical modeling of moving boundary problems in thermal energy storage

    NASA Technical Reports Server (NTRS)

    Solomon, A. D.

    1980-01-01

    The capability for predicting the performance of thermal energy storage (RES) subsystems and components using PCM's based on mathematical and physical models is developed. Mathematical models of the dynamic thermal behavior of (TES) subsystems using PCM's based on solutions of the moving boundary thermal conduction problem and on heat and mass transfer engineering correlations are also discussed.

  1. Effect of storage thermal behavior in seasonal storage solar heating systems

    NASA Astrophysics Data System (ADS)

    Lund, P. D.

    1986-12-01

    An analytical methodology has been developed to investigate the effects of storage operational strategies (or, equivalently, stratification) on the performance of a seasonal storage solar heating system with a constructed water volume. The method is based on a relative comparison between a thermally stratified and well-mixed storage system representing probable extreme outcomes of the subsystem-to-storage loop control strategies. The effects are described in the form of performance reduction factors that describe maximum changes in the solar collector yield, storage losses, and solar fraction due to storage operational mode. The study indicates that the storage thermal behavior could in the worst case affect the yearly solar fraction by a factor of 1.8, but most likely a maximum value from 1.1 to 1.5 could be expected.

  2. Optimizing Ice Thermal Storage to Reduce Energy Cost

    NASA Astrophysics Data System (ADS)

    Hall, Christopher L.

    Energy cost for buildings is an issue of concern for owners across the U.S. The bigger the building, the greater the concern. A part of this is due to the energy required to cool the building and the way in which charges are set when paying for energy consumed during different times of the day. This study will prove that designing ice thermal storage properly will minimize energy cost in buildings. The effectiveness of ice thermal storage as a means to reduce energy costs lies within transferring the time of most energy consumption from on-peak to off-peak periods. Multiple variables go into the equation of finding the optimal use of ice thermal storage and they are all judged with the final objective of minimizing monthly energy costs. This research discusses the optimal design of ice thermal storage and its impact on energy consumption, energy demand, and the total energy cost. A tool for optimal design of ice thermal storage is developed, considering variables such as chiller and ice storage sizes and charging and discharge times. The simulations take place in a four-story building and investigate the potential of Ice Thermal Storage as a resource in reducing and minimizing energy cost for cooling. The simulations test the effectiveness of Ice Thermal Storage implemented into the four-story building in ten locations across the United States.

  3. Flight experiment of thermal energy storage

    NASA Technical Reports Server (NTRS)

    Namkoong, David

    1989-01-01

    Thermal energy storage (TES) enables a solar dynamic system to deliver constant electric power through periods of sun and shade. Brayton and Stirling power systems under current considerations for missions in the near future require working fluid temperatures in the 1100 to 1300+ K range. TES materials that meet these requirements fall into the fluoride family of salts. These salts store energy as a heat of fusion, thereby transferring heat to the fluid at constant temperature during shade. The principal feature of fluorides that must be taken into account is the change in volume that occurs with melting and freezing. Salts shrink as they solidify, a change reaching 30 percent for some salts. The location of voids that form as result of the shrinkage is critical when the solar dynamic system reemerges into the sun. Hot spots can develop in the TES container or the container can become distorted if the melting salt cannot expand elsewhere. Analysis of the transient, two-phase phenomenon is being incorporated into a three-dimensional computer code. The code is capable of analysis under microgravity as well as 1 g. The objective of the flight program is to verify the predictions of the code, particularly of the void location and its effect on containment temperature. The four experimental packages comprising the program will be the first tests of melting and freezing conducted under microgravity. Each test package will be installed in a Getaway Special container to be carried by the shuttle. The package will be self-contained and independent of shuttle operations other than the initial opening of the container lid and the final closing of the lid. Upon the return of the test package from flight, the TES container will be radiographed and finally partitioned to examine the exact location and shape of the void. Visual inspection of the void and the temperature data during flight will constitute the bases for code verification.

  4. Composite materials for thermal energy storage

    DOEpatents

    Benson, D.K.; Burrows, R.W.; Shinton, Y.D.

    1985-01-04

    A composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These PCM's do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon, siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon, siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.

  5. Composite materials for thermal energy storage

    DOEpatents

    Benson, David K.; Burrows, Richard W.; Shinton, Yvonne D.

    1986-01-01

    The present invention discloses composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These phase change materials do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions, such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.

  6. Feasibility studies of aquifer thermal energy storage

    SciTech Connect

    Hall, S. H.

    1993-01-01

    Determining the feasibility of using aquifer thermal energy storage (ATES) for a particular heating or cooling application is an interdisciplinary effort, requiring (at a minimum) expertise in engineering and hydrology. The feasibility study should proceed in two distinct stages. The first stage, which is limited in scope and detail, is intended to show if an ATES system is technically and economically suited to the application. Focus of this preliminary investigation is on revealing the existence of factors that might weigh heavily against the use of ATES methods, and, in the absence of such factors, on choosing a suitable scale for the ATES plant and well field. The results of the preliminary investigation are used to determine if more detailed investigation--including field studies--are justified, and to facilitate comparing the advantages of ATES to those of other means of providing heating or cooling. The second stage of the feasibility study focuses on detailed aquifer characterization, refinement of engineering design and cost estimates, and economic and environmental risk analysis. The results of this investigation, if favorable, will be used to justify the expense of constructing the ATES system.

  7. Ocean thermal energy conversion: a review

    SciTech Connect

    Yuen, P.C.

    1981-10-01

    The OTEC principle is discussed along with general system and cycle types, specific OTEC designs, OTEC applications, and the ocean thermal resource. The historic development of OTEC is briefly reviewed, and the status of French, Japanese, EUROCEAN, and US programs is assessed. US efforts are detailed and DOE's strategy outlined with OTEC-1 and Mini-OTEC information. Power system components of the more technically advanced closed-cycle OTEC concept are discussed. These include: heat exchangers, corrosion and biofouling countermeasures, working fluids, ammonia power systems, and on-platform seawater systems. Several open-cycle features are also discussed. A critical review is presented of the ocean engineering aspects of OTEC power systems. Major subsystems such as platform, cold water pipe, mooring system, dynamic positioning system, power transmission cable system are assessed for their relationships with the ocean environment and with each other. Nine available studies of OTEC costs are reviewed. Tentative comparisons are made between OTEC and traditional fuel costs, and OTEC products and markets are considered. Possible environmental and social effects of OTEC development are discussed. International, national, and local laws regulating OTEC plants and OTEC energy products are reviewed. Tax incentives, attitudes of the utilities, and additional legislative needs are considered. (LEW)

  8. Analysis and clustering of natural gas consumption data for thermal energy use forecasting

    NASA Astrophysics Data System (ADS)

    Franco, Alessandro; Fantozzi, Fabio

    2015-11-01

    In this paper, after a brief analysis of the connections between the uses of natural gas and thermal energy use, the natural gas consumption data related to Italian market are analyzed and opportunely clustered in order to compute the typical consumption profile in different days of the week in different seasons and for the different class of users: residential, tertiary and industrial. The analysis of the data shows that natural gas consumption profile is mainly related to seasonality pattern and to the weather conditions (outside temperature, humidity and wind chiller). There is also an important daily pattern related to industrial and civil sector that, at a lower degree than the previous one, does affect the consumption profile and have to be taken into account for defining an effective short and mid term thermal energy forecasting method. A possible mathematical structure of the natural gas consumption profile is provided. Due to the strong link between thermal energy use and natural gas consumption, this analysis could be considered the first step for the development of a model for thermal energy forecasting.

  9. The Influence of Seasonal Frugivory on Nutrient and Energy Intake in Wild Western Gorillas

    PubMed Central

    Masi, Shelly; Mundry, Roger; Ortmann, Sylvia; Cipolletta, Chloé; Boitani, Luigi; Robbins, Martha M.

    2015-01-01

    The daily energy requirements of animals are determined by a combination of physical and physiological factors, but food availability may challenge the capacity to meet nutritional needs. Western gorillas (Gorilla gorilla) are an interesting model for investigating this topic because they are folivore-frugivores that adjust their diet and activities to seasonal variation in fruit availability. Observations of one habituated group of western gorillas in Bai-Hokou, Central African Republic (December 2004-December 2005) were used to examine seasonal variation in diet quality and nutritional intake. We tested if during the high fruit season the food consumed by western gorillas was higher in quality (higher in energy, sugar, fat but lower in fibre and antifeedants) than during the low fruit season. Food consumed during the high fruit season was higher in digestible energy, but not any other macronutrients. Second, we investigated whether the gorillas increased their daily intake of carbohydrates, metabolizable energy (KCal/g OM), or other nutrients during the high fruit season. Intake of dry matter, fibers, fat, protein and the majority of minerals and phenols decreased with increased frugivory and there was some indication of seasonal variation in intake of energy (KCal/g OM), tannins, protein/fiber ratio, and iron. Intake of non-structural carbohydrates and sugars was not influenced by fruit availability. Gorillas are probably able to extract large quantities of energy via fermentation since they rely on proteinaceous leaves during the low fruit season. Macronutrients and micronutrients, but not digestible energy, may be limited for them during times of low fruit availability because they are hind-gut fermenters. We discuss the advantages of seasonal frugivores having large dietary breath and flexibility, significant characteristics to consider in the conservation strategies of endangered species. PMID:26154509

  10. Composite materials for thermal energy storage: enhancing performance through microstructures.

    PubMed

    Ge, Zhiwei; Ye, Feng; Ding, Yulong

    2014-05-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are investigated. The ceramic supporting material is essential for preventing salt leakage and hence provides a solution to the chemical incompatibility issue. The use of graphite gives a significant enhancement on the thermal conductivity of the composite. Analyses suggest that the experimentally observed microstructural development of the composite is associated with the wettability of the salt on the ceramic substrate and that on the thermal conduction enhancer.

  11. Anisotropy Enhancement of Thermal Energy Transport in Supported Black Phosphorene.

    PubMed

    Chen, Jige; Chen, Shunda; Gao, Yi

    2016-07-07

    Thermal anisotropy along the basal plane of materials possesses both theoretical importance and application value in thermal transport and thermoelectricity. Though common two-dimensional materials may exhibit in-plane thermal anisotropy when suspended, thermal anisotropy would often disappear when supported on a substrate. In this Letter, we find a strong anisotropy enhancement of thermal energy transport in supported black phosphorene. The chiral preference of energy transport in the zigzag rather than the armchair direction is greatly enhanced by coupling to the substrate, up to a factor of approximately 2-fold compared to the suspended one. The enhancement originates from its puckered lattice structure, where the nonplanar armchair energy transport relies on the out-of-plane corrugation and thus would be hindered by the flexural suppression due to the substrate, while the planar zigzag energy transport is not. As a result, thermal conductivity of supported black phosphorene shows a consistent anisotropy enhancement under different temperatures and substrate coupling strengths.

  12. Thermal noise can facilitate energy conversion by a ratchet system.

    PubMed

    Takagi, F; Hondou, T

    1999-10-01

    Molecular motors in biological systems are expected to use ambient fluctuation. In a recent paper [Phys. Rev. Lett. 80, 5251 (1998)], it was shown that the following question was unanswered: Can thermal noise facilitate energy conversion by ratchet system? We consider it using stochastic energetics, and show that there exist systems where thermal noise helps the energy conversion.

  13. Solar-thermal conversion and thermal energy storage of graphene foam-based composites

    NASA Astrophysics Data System (ADS)

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-07-01

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a

  14. The seasonal cycle of water vapour on Mars from assimilation of Thermal Emission Spectrometer data

    NASA Astrophysics Data System (ADS)

    Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, François; Smith, Michael D.

    2014-07-01

    We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr μm depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around LS=240-260°. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

  15. A seasonality trigger for carbon injection at the Paleocene-Eocene Thermal Maximum

    NASA Astrophysics Data System (ADS)

    Eldrett, J. S.; Greenwood, D. R.; Polling, M.; Brinkhuis, H.; Sluijs, A.

    2014-04-01

    The Paleocene-Eocene Thermal Maximum (PETM) represents a ~170 kyr episode of anomalous global warmth ~56 Ma ago. The PETM is associated with rapid and massive injections of 13C-depleted carbon into the ocean-atmosphere system reflected as a prominent negative carbon isotope excursion (CIE) in sedimentary components. Earth's surface and deep ocean waters warmed by ~5 °C, of which part may have occurred prior to the CIE. However, few records document continental climatic trends and changes in seasonality have not been documented. Here we present the first high-resolution vegetation and paleoclimate reconstructions for the PETM, based on nearest living relative analysis of terrestrially derived spore and pollen assemblages preserved in an expanded section from the central North Sea. Our data indicate reductions in boreal conifers and an increase in mesothermal to megathermal taxa, reflecting a shift towards wetter and warmer climate. We also record an increase in summer temperatures, greater in magnitude than the rise in mean annual temperature changes, and a shift to a summer-wet seasonality. Within the CIE, vegetation varies significantly with initial increases in epiphytic and climbing ferns, and development of extensive wetlands, followed by abundance of Carya spp. indicative of broadleaf forest colonization. Critically, the change in vegetation we report occurs prior to the CIE, and is concomitant with anomalous marine ecological change, as represented by the occurrence of Apectodinium augustum. This suggests that amplifications of seasonal extremes triggered carbon injection.

  16. The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

    NASA Technical Reports Server (NTRS)

    Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

    2014-01-01

    We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

  17. Method and apparatus for thermal energy storage. [Patent application

    DOEpatents

    Gruen, D.M.

    1975-08-19

    A method and apparatus for storing energy by converting thermal energy to potential chemically bound energy in which a first metal hydride is heated to dissociation temperature, liberating hydrogen gas which is compressed and reacted with a second metal to form a second metal hydride while releasing thermal energy. Cooling the first metal while warming the second metal hydride to dissociation temperature will reverse the flow of hydrogen gas back to the first metal, releasing additional thermal energy. The method and apparatus are particularly useful for the storage and conversion of thermal energy from solar heat sources and for the utilization of this energy for space heating purposes, such as for homes or offices.

  18. Eddy covariance measurements of surface energy budget and evaporation in a cool season over southern open water in Mississippi

    NASA Astrophysics Data System (ADS)

    Liu, Heping; Zhang, Yu; Liu, Shuhua; Jiang, Haimei; Sheng, Li; Williams, Quinton L.

    2009-02-01

    Eddy covariance measurements of sensible (H) and latent (LE) heat fluxes were made over a large southern open water surface of Ross Barnett Reservoir (the Reservoir hereafter) in Mississippi during the cool season with frequent incursions of cold fronts from 1 September 2007 to 31 January 2008. The eddy covariance tower was located in the middle of the main body of the Reservoir with the tower fetches exceeding 2.0 km in all directions. The Reservoir was ice-free in winter and the water temperatures always decreased with depth. Over the entire cool season, the averaged water surface temperatures were 1.8°C higher than the overlying air (i.e., positive temperature gradients that led to thermally convective conditions) and the averaged vapor pressure near the water surface was 0.8 kPa greater than the overlying air (i.e., positive vapor pressure gradients), though occasionally negative gradients for temperature and vapor pressure were also observed for short periods. On average, the wind speeds were considerably large (3.9 m s-1) to maintain adequate turbulent mixing mechanically. As a consequence of the combined effect of thermally and mechanically generated turbulent mixing, consistently positive H (with a mean H of 20.0 W m-2) and LE (with a mean LE of 80.0 W m-2) occurred during the entire season. These continuous energy losses via H and LE resulted in release of a large amount of energy stored in the water to the atmosphere. The mean Bowen ratio was low for this open water surface (i.e., 0.3), suggesting that most of the energy released from the water fueled evaporation rather than sensible heating of the atmosphere. Nighttime evaporative water losses were substantial, contributing to 45% of the total evaporative water loss in this cool season. Frequent incursions of cold fronts with windy, cold, and dry air masses significantly promoted turbulent exchanges of sensible and latent heat through enhanced turbulent mixing thermally and mechanically, leading to

  19. Seasonal Evolution of Thermal Stratification of Two High Mountain Tropical Reservoirs

    NASA Astrophysics Data System (ADS)

    Arbelaez, A. C.; Román-Botero, R.; Gómez-Giraldo, A.; Toro, M.

    2014-12-01

    A research was conducted to identify the dominant basin scale and season evolution of the physical processes in Riogrande II and La Fe, two high mountain Andean tropical reservoirs (>2000 masl), of different size and form, located in the northwestern of Colombia, Southamerica. Eight field campaigns were conducted in each reservoir between 2010 and 2012. Temperature, conductivity and turbidity profiles were measured along the longitudinal axes with a CTD and inflow temperature was recorded continuously with thermistors. In addition, thermistor chains were deployed on the deepest zone of each reservoir, in 2011 in La Fe and in 2013 in Riogrande II. The heat surface fluxes were calculated based on weather measurements, using heat bulk-formulations. It was found that the seasonal variability of the thermal structure in both reservoirs was dominated mainly by changes in the inflows temperature, related to the hydrological cycle, and not by the solar radiation variability. The atmospheric net heat flux revealed low seasonal changes, with the larger variability due to cloud cover and wind speed variability associated to the passage of the Intertropical Convergence Zone. The effect of the net atmospheric flux was confined to the surface mixed layer, which thickness varied between 2 and 4 m by the effect of short wave radiation heating during the day and strong heat loss starting at mid afternoon and remaining through the night. The inflow temperature was inversely correlated to the discharge, so large inflows are also colder and denser than small inflows. The plumes from small inflows are intrusive and create an intermediate layer of young water while those of large inflows remain attached to the bottom and fill the reservoir from the bottom. This resulted in the thermal structure of both reservoirs developing a bimodal annual cycle that follows the bimodal distribution of the rainfall and river discharge. Due to the discharge related changing level of the intrusion of the

  20. Impact of improved building thermal efficiency on residential energy demand

    SciTech Connect

    Adams, R.C.; Rockwood, A.D.

    1983-04-01

    The impact of improved building shell thermal efficiency on residential energy demand is explored in a theoretical framework. The important economic literature on estimating the price elasticity of residential energy demand is reviewed. The specification of the residential energy demand model is presented. The data used are described. The empirical estimation of the residential energy demand model is described. (MHR)

  1. Using thermal units for estimating critical period of weed competition in off-season maize crop.

    PubMed

    López-Ovejero, Ramiro Fernando; y Garcia, Axel Garcia; de Carvalho, Saul Jorge P; Christoffoleti, Pedro J; Neto, Durval Dourado; Martins, Fernando; Nicolai, Marcelo

    2005-01-01

    Brazilian off-season maize production is characterized by low yield due to several factors, such as climate variability and inadequate management practices, specifically weed management. Thus, the goal of this study was to determinate the critical period of weed competition in off-season maize (Zea mays L.) crop using thermal units or growing degree days (GDD) approach to characterize crop growth and development. The study was carried out in experimental area of the University of São Paulo, Brazil, with weed control (C), as well as seven coexistence periods, 2, 4, 6, 8, and 12 leaves, flowering, and all crop cycle; fourteen treatments were done. Climate data were obtained from a weather station located close to the experimental area. To determine the critical period for weed control (CPWC) logistic models were fitted to yield data obtained in both W and C, as a function of GDD. For an arbitrary maximum yield loss fixed in 2.5%, the CPWC was found between 301 and 484 GDD (7-8 leaves). Also, when the arbitrary loss yield was fixed in 5 and 10%, the period before interference (PBI) was higher than the critical weed-free period (CWFP), suggesting that the weeds control can be done with only one application, between 144 and 410 GDD and 131 and 444 GDD (3-8 leaves), respectively. The GDD approach to characterize crop growth and development was successfully used to determine the critical period of weeds control in maize sown off-season. Further works will be necessary to better characterize the interaction and complexity of maize sown off-season with weeds. However, these results are encouraging because the possibility of the results to be extrapolated and because the potential of the method on providing important results to researchers, specifically crop modelers.

  2. Open cycle ocean thermal energy conversion system

    DOEpatents

    Wittig, J. Michael

    1980-01-01

    An improved open cycle ocean thermal energy conversion system including a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed warm ocean water exits the evaporator through a second prestressed concrete skirt-conduit structure located circumferentially about and radially within the first skirt-conduit structure. The radially inner surface of the second skirt conduit structure constitutes a cylinder which functions as the turbine's outer casing and obviates the need for a conventional outer housing. The turbine includes a radially enlarged disc element attached to the shaft for supporting at least one axial row of radially directed blades through which the steam is expanded. A prestressed concrete inner casing structure of the turbine has upstream and downstream portions respectively situated upstream and downstream from the disc element. The radially outer surfaces of the inner casing portions and radially outer periphery of the axially interposed disc cooperatively form a downwardly radially inwardly tapered surface. An annular steam flowpath of increasing flow area in the downward axial direction is radially bounded by the inner and outer prestressed concrete casing structures. The inner casing portions each include a transversely situated prestressed concrete circular wall for rotatably supporting the turbine shaft and associated structure. The turbine blades are substantially radially coextensive with the steam flowpath and receive steam from the evaporator through an annular array of prestressed concrete stationary vanes which extend between the inner and outer casings to provide structural support therefor and impart a desired flow direction to the steam.

  3. Thermal Energy Storage in Phase Change Material.

    DTIC Science & Technology

    1982-03-01

    Graphs of the exnerimental results follow: tney are groupea in the tree categories: tube cross flow, ricked bed, and tube parallel flow. A. Tube Cross... Riordan , Michael, "Thermal Storage: A Rtsic Guile to the Ptate of the Art", Solar Age, Aril, 1978, P. 10. 5. Telkes, Maria, "Thermal Lner y Storage in

  4. Seasonal and Non-Seasonal Variations of Jupiter's Atmosphere from Observations of Thermal Emission, 1994-2011

    NASA Technical Reports Server (NTRS)

    Orton, G.; Fletcher, L.; Yanamandra-Fisher, P.; Greathouse, T.; Fisher, B.; Greco, J.; Wakefield, L.; Snead, E.; Boydstun, K.; Simon-Miller, A.; Arzumanyan, G.; Christian, J.

    2012-01-01

    We analyzed mid-infrared images of Jupiter's thermal emission, covering approx.1.5 Jovian years, acquired in discrete filters between 7.8 and 24.5 microns. The behavior of stratospheric (approx.10-mbar) and tropospheric (approx.100-400 mbar) temperatures is generally consistent with predictions of seasonal variability, with differences between 100-mbar temperatures +/-50-60deg from the equator on the order of +/-2. Removing this effect, there appear to be long-term quasi-periodic variability of tropospheric temperatures, whose amplitude, phase and period depend on latitude. The behavior of temperatures in the Equatorial Zone (EZ) suggests a approx.4-6-year period with amplitude of about +/-1-1.5 K in temperature. At mid-latitudes, the periodicity is more distinct with amplitudes around +/-1.5-2.5 K and 4-8 year periods. The 4.2-year variation of stratospheric temperatures known as the quasiquadrennial oscillation or "QQO" (Leovy et al. 1991, Nature 354, 380) continued during this period. There were no variations of zonal mean temperatures associated with any of the "global upheaval" events that have produced dramatic changes of jupiter's visible appearance and cloud cover, although there are colder discrete regions associated with updrafts, e.g. the early stages of the re-darkening ("revival") of the South Equatorial Belt (SEB) in late 2010. On the other hand increases in the visible albedos ("fades") of belts are accompanied by increases in the thickness of a 700-mbar cloud layer (most likely NH3 ice) and clouds at higher pressures, together with the mixing ratio of NH3 gas near 400 mbar (above its condensation level). These quantities decrease during re-darkening ("revival") episodes, during which we note discrete features that are exceptions to the general correlation between dark albedos and minimal cloudiness. In contrast to all these changes, the meridional distribution of the 240-mbar para-H2 fraction appears to be invariant in time.

  5. Simple energy balance model resolving the seasons and the continents - Application to the astronomical theory of the ice ages

    NASA Technical Reports Server (NTRS)

    North, G. R.; Short, D. A.; Mengel, J. G.

    1983-01-01

    An analysis is undertaken of the properties of a one-level seasonal energy balance climate model having explicit, two-dimensional land-sea geography, where land and sea surfaces are strictly distinguished by the local thermal inertia employed and transport is governed by a smooth, latitude-dependent diffusion mechanism. Solutions of the seasonal cycle for the cases of both ice feedback exclusion and inclusion yield good agreements with real data, using minimal turning of the adjustable parameters. Discontinuous icecap growth is noted for both a solar constant that is lower by a few percent and a change of orbital elements to favor cool Northern Hemisphere summers. This discontinuous sensitivity is discussed in the context of the Milankovitch theory of the ice ages, and the associated branch structure is shown to be analogous to the 'small ice cap' instability of simpler models.

  6. Photoswitchable Molecular Rings for Solar-Thermal Energy Storage.

    PubMed

    Durgun, E; Grossman, Jeffrey C

    2013-03-21

    Solar-thermal fuels reversibly store solar energy in the chemical bonds of molecules by photoconversion, and can release this stored energy in the form of heat upon activation. Many conventional photoswichable molecules could be considered as solar thermal fuels, although they suffer from low energy density or short lifetime in the photoinduced high-energy metastable state, rendering their practical use unfeasible. We present a new approach to the design of chemistries for solar thermal fuel applications, wherein well-known photoswitchable molecules are connected by different linker agents to form molecular rings. This approach allows for a significant increase in both the amount of stored energy per molecule and the stability of the fuels. Our results suggest a range of possibilities for tuning the energy density and thermal stability as a function of the type of the photoswitchable molecule, the ring size, or the type of linkers.

  7. Building heating and cooling applications thermal energy storage program overview

    NASA Technical Reports Server (NTRS)

    Eissenberg, D. M.

    1980-01-01

    Thermal energy storage technology and development of building heating and cooling applications in the residential and commercial sectors is outlined. Three elements are identified to undergo an applications assessment, technology development, and demonstration. Emphasis is given to utility load management thermal energy system application where the stress is on the 'customer side of the meter'. Thermal storage subsystems for space conditioning and conservation means of increased thermal mass within the building envelope and by means of low-grade waste heat recovery are covered.

  8. Rapid estimation of glucosinolate thermal degradation rate constants in leaves of Chinese kale and broccoli (Brassica oleracea) in two seasons.

    PubMed

    Hennig, Kristin; Verkerk, Ruud; Bonnema, Guusje; Dekker, Matthijs

    2012-08-15

    Kinetic modeling was used as a tool to quantitatively estimate glucosinolate thermal degradation rate constants. Literature shows that thermal degradation rates differ in different vegetables. Well-characterized plant material, leaves of broccoli and Chinese kale plants grown in two seasons, was used in the study. It was shown that a first-order reaction is appropriate to model glucosinolate degradation independent from the season. No difference in degradation rate constants of structurally identical glucosinolates was found between broccoli and Chinese kale leaves when grown in the same season. However, glucosinolate degradation rate constants were highly affected by the season (20-80% increase in spring compared to autumn). These results suggest that differences in glucosinolate degradation rate constants can be due to variation in environmental as well as genetic factors. Furthermore, a methodology to estimate rate constants rapidly is provided to enable the analysis of high sample numbers for future studies.

  9. Solar-thermal conversion and thermal energy storage of graphene foam-based composites.

    PubMed

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-08-14

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  10. Thermal energy dissipation and xanthophyll cycles beyond the Arabidopsis model.

    PubMed

    García-Plazaola, José Ignacio; Esteban, Raquel; Fernández-Marín, Beatriz; Kranner, Ilse; Porcar-Castell, Albert

    2012-09-01

    Thermal dissipation of excitation energy is a fundamental photoprotection mechanism in plants. Thermal energy dissipation is frequently estimated using the quenching of the chlorophyll fluorescence signal, termed non-photochemical quenching. Over the last two decades, great progress has been made in the understanding of the mechanism of thermal energy dissipation through the use of a few model plants, mainly Arabidopsis. Nonetheless, an emerging number of studies suggest that this model represents only one strategy among several different solutions for the environmental adjustment of thermal energy dissipation that have evolved among photosynthetic organisms in the course of evolution. In this review, a detailed analysis of three examples highlights the need to use models other than Arabidopsis: first, overwintering evergreens that develop a sustained form of thermal energy dissipation; second, desiccation tolerant plants that induce rapid thermal energy dissipation; and third, understorey plants in which a complementary lutein epoxide cycle modulates thermal energy dissipation. The three examples have in common a shift from a photosynthetically efficient state to a dissipative conformation, a strategy widely distributed among stress-tolerant evergreen perennials. Likewise, they show a distinct operation of the xanthophyll cycle. Expanding the list of model species beyond Arabidopsis will enhance our knowledge of these mechanisms and increase the synergy of the current studies now dispersed over a wide number of species.

  11. Seasonal Variability in Calorimetric Energy Content of Two Caribbean Mesophotic Corals

    PubMed Central

    Brandtneris, Viktor W.; Brandt, Marilyn E.; Glynn, Peter W.; Gyory, Joanna; Smith, Tyler B.

    2016-01-01

    Energetic responses of zooxanthellate reef corals along depth gradients have relevance to the refugia potential of mesophotic coral ecosystems (MCEs). Previous observations suggested that MCEs in the Caribbean are thermally buffered during the warmest parts of the year and occur within or just below the chlorophyll maximum, suggesting abundant trophic resources. However, it is not known if mesophotic corals can maintain constant energy needs throughout the year with changing environmental and biological conditions. The energetic content of tissues from the stony coral species Orbicella faveolata and Agaricia lamarcki was measured on the southern insular shelf of St. Thomas, US Virgin Islands (USVI), using micro-bomb calorimetry. Three sites for each species, at depths of 6m, 25m, 38m and 63m, were selected to capture energetic differences across the major vertical range extent of both species in the USVI—and sampled over five periods from April 2013 to April 2014. Mesophotic colonies of O. faveolata exhibited a significant reduction in energetic content during the month of September 2013 compared to mid-depth and shallow colonies (p = 0.032), whereas A. lamarcki experienced similar energetic variability, but with a significant reduction in energy content that occurred in July 2013 for colonies at sites deeper than 25m (p = 0.014). The results of calorimetric analyses indicate that O. faveolata may be at risk during late summer stress events, possibly due to the timing of reproductive activities. The low-point of A. lamarcki energy content, which may also coincide with reproduction, occurs prior to seasonal stress events, indicating contrasting, species-specific responses to environmental variability on MCEs. PMID:27050430

  12. Physiological responses in rufous-collared sparrows to thermal acclimation and seasonal acclimatization.

    PubMed

    Maldonado, Karin Evelyn; Cavieres, Grisel; Veloso, Claudio; Canals, Mauricio; Sabat, Pablo

    2009-04-01

    A large number of physiological acclimation studies assume that flexibility in a certain trait is both adaptive and functionally important for organisms in their natural environment; however, it is not clear how an organism's capacity for temperature acclimation translates to the seasonal acclimatization that these organisms must accomplish. To elucidate this relationship, we measured BMR and TEWL rates in both field-acclimatized and laboratory-acclimated adult rufous-collared sparrows (Zonotrichia capensis). Measurements in field-acclimatized birds were taken during the winter and summer seasons; in the laboratory-acclimated birds, we took our measurements following 4 weeks at either 15 or 30 degrees C. Although BMR and TEWL rates did not differ between winter and summer in the field-acclimatized birds, laboratory-acclimated birds exposed to 15 degrees C exhibited both a higher BMR and TEWL rate when compared to the birds acclimated to 30 degrees C and the field-acclimatized birds. Because organ masses seem to be similar between field and cold-acclimated birds whereas BMR is higher in cold-acclimated birds, the variability in BMR cannot be explained completely by adjustments in organ masses. Our findings suggest that, although rufous-collared sparrows can exhibit thermal acclimation of physiological traits, sparrows do not use this capacity to cope with minor to moderate fluctuations in environmental conditions. Our data support the hypothesis that physiological flexibility in energetic traits is a common feature of avian metabolism.

  13. A seasonality trigger for carbon injection at the Paleocene-Eocene thermal maximum

    NASA Astrophysics Data System (ADS)

    Eldrett, J. S.; Greenwood, D. R.; Polling, M.; Brinkhuis, H.; Sluijs, A.

    2013-10-01

    The Paleocene-Eocene thermal maximum (PETM) represents a ~170 kyr episode of anomalous global warmth ~56 Ma ago. The PETM is associated with rapid and massive injections of 13C-depleted carbon into the ocean-atmosphere system reflected as a prominent negative carbon isotope excursion (CIE) in sedimentary components. Earth's surface and deep ocean waters warmed by ~5 °C, of which part may have occurred prior to the CIE. However, few records document continental climatic trends and changes in seasonality have not been documented. Here we present the first high-resolution vegetation reconstructions for the PETM, based on bioclimatic analysis of terrestrially-derived spore and pollen assemblages preserved in an expanded section from the Central North Sea. Our data indicate reductions in boreal conifers and an increase in mesothermal to megathermal taxa, reflecting a shift towards wetter and warmer climate. We also record an increase in summer temperatures, greater in magnitude than the rise in mean annual temperature changes. Within the CIE, vegetation varies significantly with initial increases in epiphytic and climbing ferns, and development of extensive wetlands, followed by abundance of Carya spp. indicative of broadleaf forest colonization. Critically, the change in vegetation we report occurs prior to the CIE, and is concomitant with anomalous marine ecological change, as represented by the occurrence of Apectodinium augustum. This suggests that amplifications of seasonal extremes triggered carbon injection.

  14. Thermal energy storage for industrial waste heat recovery

    NASA Technical Reports Server (NTRS)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    Thermal energy storage systems designed for energy conservation through the recovery, storage, and reuse of industrial process waste heat are reviewed. Consideration is given to systems developed for primary aluminum, cement, the food processing industry, paper and pulp, and primary iron and steel. Projected waste-heat recovery and energy savings are listed for each category.

  15. Buffer thermal energy storage for an air Brayton solar engine

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    The application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine was studied. To demonstrate the effect of buffer thermal energy storage on engine operation, a computer program was written which models the recuperator, receiver, and thermal storage device as finite-element thermal masses. Actual operating or predicted performance data are used for all components, including the rotating equipment. Based on insolation input and a specified control scheme, the program predicts the Brayton engine operation, including flows, temperatures, and pressures for the various components, along with the engine output power. An economic parametric study indicates that the economic viability of buffer thermal energy storage is largely a function of the achievable engine life.

  16. Solar photovoltaic/thermal (hybrid) energy project

    NASA Astrophysics Data System (ADS)

    Sheldon, D. B.

    1981-09-01

    Development of photovoltaic/thermal (PV/T) collectors and residential heat pump systems is reported. Candidate collector and residential heat pump systems were evaluated using the TRNSYS computer program. It is found that combined heat pump and PV array is a promising method for achieving economical solar cooling. Where the cooling load is dominant, exclusively PV collectors rather than PV/T collectors are preferred. Where the heating load is dominant, the thermal component of PV/T collectors makes a significant contribution to heating a residence. PV/T collectors were developed whose combined efficiency approaches the efficiency of a double glazed, exclusively thermal collector. The design and operational problems of air source heat pumps are reviewed. Possible effects of compressor startup transients on PV power system operation are discussed.

  17. Seasonal differences in the subjective assessment of outdoor thermal conditions and the impact of analysis techniques on the obtained results

    NASA Astrophysics Data System (ADS)

    Kántor, Noémi; Kovács, Attila; Takács, Ágnes

    2016-11-01

    Wide research attention has been paid in the last two decades to the thermal comfort conditions of different outdoor and semi-outdoor urban spaces. Field studies were conducted in a wide range of geographical regions in order to investigate the relationship between the thermal sensation of people and thermal comfort indices. Researchers found that the original threshold values of these indices did not describe precisely the actual thermal sensation patterns of subjects, and they reported neutral temperatures that vary among nations and with time of the year. For that reason, thresholds of some objective indices were rescaled and new thermal comfort categories were defined. This research investigates the outdoor thermal perception patterns of Hungarians regarding the Physiologically Equivalent Temperature ( PET) index, based on more than 5800 questionnaires. The surveys were conducted in the city of Szeged on 78 days in spring, summer, and autumn. Various, frequently applied analysis approaches (simple descriptive technique, regression analysis, and probit models) were adopted to reveal seasonal differences in the thermal assessment of people. Thermal sensitivity and neutral temperatures were found to be significantly different, especially between summer and the two transient seasons. Challenges of international comparison are also emphasized, since the results prove that neutral temperatures obtained through different analysis techniques may be considerably different. The outcomes of this study underline the importance of the development of standard measurement and analysis methodologies in order to make future studies comprehensible, hereby facilitating the broadening of the common scientific knowledge about outdoor thermal comfort.

  18. Solar Thermal Energy Storage in a Photochromic Macrocycle.

    PubMed

    Vlasceanu, Alexandru; Broman, Søren L; Hansen, Anne S; Skov, Anders B; Cacciarini, Martina; Kadziola, Anders; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

    2016-07-25

    The conversion and efficient storage of solar energy is recognized to hold significant potential with regard to future energy solutions. Molecular solar thermal batteries based on photochromic systems exemplify one possible technology able to harness and apply this potential. Herein is described the synthesis of a macrocycle based on a dimer of the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermal couple. By taking advantage of conformational strain, this DHA-DHA macrocycle presents an improved ability to absorb and store incident light energy in chemical bonds (VHF-VHF). A stepwise energy release over two sequential ring-closing reactions (VHF→DHA) combines the advantages of an initially fast discharge, hypothetically addressing immediate energy consumption needs, followed by a slow process for consistent, long-term use. This exemplifies another step forward in the molecular engineering and design of functional organic materials towards solar thermal energy storage and release.

  19. Applications of thermal energy storage in the cement industry

    NASA Technical Reports Server (NTRS)

    Jaeger, F. A.; Beshore, D. G.; Miller, F. M.; Gartner, E. M.

    1978-01-01

    In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, established use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10 to the 13th power Btu/year, or an equivalent on investment of the proposed systems are an incentive for further development.

  20. Seasonal changes of apparent thermal diffusivity of different kinds of soils

    NASA Astrophysics Data System (ADS)

    Dedecek, Petr; Safanda, Jan; Correia, Antonio; Rajver, Dusan; Cermak, Vladimir; Kresl, Milan

    2013-04-01

    The paper addresses the problem of seasonal changes of apparent thermal diffusivity (ATD) in different types of soils in different climatic conditions. The long-term (several years) temperature series recorded at observatories in Czechia, Slovenia and Portugal were processed using a program based on the error function solution of the heat conduction equation for a semi-infinite solid. The program simulates penetration of temperature changes represented by the observed time-temperature series in differently wide time floating intervals, and in different depth levels of the soil profile. Synthetic temperature series for different values of thermal diffusivity (with a step of 1E-8 m2/s) are automatically compared with measured temperature time series in a given depth. The ATD value minimizing the standard deviation of difference between the measured and computed temperature series is considered as the best approximation of reality. The method has been applied to the temperature series from (i) observatory in Prague, where the temperature monitoring in different kinds of soil (sand, bare clayey soil, grassy soil) and asphalt is running from 2002, (ii) Evora - Portugal (gravelly sand, running from 2005), and finally (iii) Malence - Slovenia (grassy clayey soil, running from 2003). The soil temperature is measured at the depths of 2, 5, 10, 20 and 50 cm at each of the observatories. Results have shown a gradual increase of the ATD with depth caused by the soil density gradient in case of Malence and Prague (excluding asphalt). The ATD of the upper part of sand (2 - 5 cm), contrary to grassy surface, is quite sensitive to weather pattern (e.g. periods of rain or drought), when the strong convective heat transport in soil can occur. The ATD values in Evora show an annual run connected with a long dry summer season. The seasonal pattern is characterized, especially in the upper part of soil, by a rapid decrease from 7*E-7 to 4*E-7 m2/s in June and a return to higher values

  1. Making Heat Visible: Promoting Energy Conservation Behaviors Through Thermal Imaging.

    PubMed

    Goodhew, Julie; Pahl, Sabine; Auburn, Tim; Goodhew, Steve

    2015-12-01

    Householders play a role in energy conservation through the decisions they make about purchases and installations such as insulation, and through their habitual behavior. The present U.K. study investigated the effect of thermal imaging technology on energy conservation, by measuring the behavioral effect after householders viewed images of heat escaping from or cold air entering their homes. In Study 1 (n = 43), householders who received a thermal image reduced their energy use at a 1-year follow-up, whereas householders who received a carbon footprint audit and a non-intervention control demonstrated no change. In Study 2 (n = 87), householders were nearly 5 times more likely to install draught proofing measures after seeing a thermal image. The effect was especially pronounced for actions that addressed an issue visible in the images. Findings indicate that using thermal imaging to make heat loss visible can promote energy conservation.

  2. Energy consumption in buildings and female thermal demand

    NASA Astrophysics Data System (ADS)

    Kingma, Boris; van Marken Lichtenbelt, Wouter

    2015-12-01

    Energy consumption of residential buildings and offices adds up to about 30% of total carbon dioxide emissions; and occupant behaviour contributes to 80% of the variation in energy consumption. Indoor climate regulations are based on an empirical thermal comfort model that was developed in the 1960s (ref. ). Standard values for one of its primary variables--metabolic rate--are based on an average male, and may overestimate female metabolic rate by up to 35% (ref. ). This may cause buildings to be intrinsically non-energy-efficient in providing comfort to females. Therefore, we make a case to use actual metabolic rates. Moreover, with a biophysical analysis we illustrate the effect of miscalculating metabolic rate on female thermal demand. The approach is fundamentally different from current empirical thermal comfort models and builds up predictions from the physical and physiological constraints, rather than statistical association to thermal comfort. It provides a substantiation of the thermal comfort standard on the population level and adds flexibility to predict thermal demand of subpopulations and individuals. Ultimately, an accurate representation of thermal demand of all occupants leads to actual energy consumption predictions and real energy savings of buildings that are designed and operated by the buildings services community.

  3. Pulse thermal energy transport/storage system

    DOEpatents

    Weislogel, Mark M.

    1992-07-07

    A pulse-thermal pump having a novel fluid flow wherein heat admitted to a closed system raises the pressure in a closed evaporator chamber while another interconnected evaporator chamber remains open. This creates a large pressure differential, and at a predetermined pressure the closed evaporator is opened and the opened evaporator is closed. This difference in pressure initiates fluid flow in the system.

  4. Seasonal changes of thermal diffusivity and their effect on heat transfer in soils

    NASA Astrophysics Data System (ADS)

    Dedecek, Petr; Correia, Antonio; Safanda, Jan; Cermak, Vladimir; Rajver, Dusan; Pechacova, Blanka

    2016-04-01

    The aim of the work is to describe the effects of seasonal changes of thermal diffusivity (TD) on the thermal regime in shallow subsurface soils. The long term temperature series from observatories at Prague (Czechia), Evora (Portugal) and Malence (Slovenia) were processed by newly improved code which enables a detailed calculation of time changes of TD of the soils. To determine the effect of climate warming of the recent years and to describe the possible effect of TD changes on the temperature-depth profiles, time dependent numerical models were computed. In the case of Evora, the effect of the TD changes on mean annual temperatures was confirmed. This observatory is located on bare sandy surface and TD in the upper soil layer significantly decreases (up to 50%) in summer months. It is due to local climate, which is typical by alternating winter/wet and summer/dry periods. The negative temperature gradient in the depth of 2-5 cm increases with TD decreasing, the coefficient of determination is 0.6 (2012). The TD decreasing during the summer months substitutes the effect of vegetation and controls the heat transfer to the subsurface. The climate in Prague and Malence is typical by rainy/snowy periods during the whole year and effect of TD changes in bare sandy soils is only short-term, or even insignificant under grassy surfaces.

  5. Seasonal eddy kinetic energy modulations along the North Equatorial Countercurrent in the western Pacific

    NASA Astrophysics Data System (ADS)

    Chen, Xiao; Qiu, Bo; Chen, Shuiming; Qi, Yiquan; Du, Yan

    2015-09-01

    Seasonal eddy kinetic energy (EKE) variability and its associated eddy energy conversion processes in the western tropical Pacific are investigated using satellite altimeter observations and a global, eddy-resolving, ocean general circulation model (OGCM). Both the altimeter-observed sea surface height anomalies and the OGCM simulation show an area with enhanced EKE east of the Mindanao Island centered around 133°E and 5°N. This enhanced EKE area corresponds to the location of the quasi-stationary meander of the North Equatorial Countercurrent (NECC) and is bordered to the south by the Halmahera Eddy. The mesoscale EKE in this area exhibits a clear seasonality, strong in summer (July-August) and weak in winter (November-January), and much of this seasonality is confined to the upper 200 m layer. An investigation into the upper ocean eddy energetics based on the OGCM simulation reveals that the areal barotropic eddy energy conversion rate has an annual cycle similar to the EKE variations, while the areal baroclinic eddy energy conversion is found to be much smaller that the barotropic conversion rate and exhibits no clear seasonal changes. This indicates that the EKE variations are largely controlled by barotropic conversion of the seasonally varying regional circulation. By examining the seasonal background circulation changes, we find that the amplification of the barotropic eddy energy conversion rate in July-August is related to the seasonal evolution of the Mindanao Current and the New Guinea Coastal Current that amplifies the curvature and amplitude of the quasi-stationary meander of the NECC and results in an elevated EKE level through increased regional barotropic conversion.

  6. Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)

    SciTech Connect

    Demuth, R.B.; Harlow, F.H.

    1980-12-01

    A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling of the rock produces thermal stresses that fracture the rock adjacent to the primary crack, thereby enhancing the heat extraction rate by means of convective transport. The properties of the thermal fracture network vary with position and time. The REX code for high-speed computer was written and used to study the coupled processes of primary-crack flow and lateral thermal fracture heat transport. Calculations for elapsed times of 100 y show that thermal fracture enhancement can double the heat extraction rate over the results from conduction alone. Long-term enhancement predictions depend on data from rock-mechanics studies, which the REX code is prepared to accept as they become available.

  7. Design Considerations of a Solid State Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    Janbozorgi, Mohammad; Houssainy, Sammy; Thacker, Ariana; Ip, Peggy; Ismail, Walid; Kavehpour, Pirouz

    2016-11-01

    With the growing governmental restrictions on carbon emission, renewable energies are becoming more prevalent. A reliable use of a renewable source however requires a built-in storage to overcome the inherent intermittent nature of the available energy. Thermal design of a solid state energy storage has been investigated for optimal performance. The impact of flow regime, laminar vs. turbulent, on the design and sizing of the system is also studied. The implications of low thermal conductivity of the storage material are discussed and a design that maximizes the round trip efficiency is presented. This study was supported by Award No. EPC-14-027 Granted by California Energy Commission (CEC).

  8. Legal and regulatory issues affecting aquifer thermal energy storage

    SciTech Connect

    Hendrickson, P.L.

    1981-10-01

    This document updates and expands the report with a similar title issued in October 1980. This document examines a number of legal and regulatory issues that potentially can affect implementation of the aquifer thermal energy storage (ATES) concept. This concept involves the storage of thermal energy in an underground aquifer until a later date when it can be effectively utilized. Either heat energy or chill can be stored. Potential end uses of the energy include district space heating and cooling, industrial process applications, and use in agriculture or aquaculture. Issues are examined in four categories: regulatory requirements, property rights, potential liability, and issues related to heat or chill delivery.

  9. Thermally driven electrokinetic energy conversion with liquid water microjets

    NASA Astrophysics Data System (ADS)

    Lam, Royce K.; Gamlieli, Zach; Harris, Stephen J.; Saykally, Richard J.

    2015-11-01

    A goal of current energy research is to design systems and devices that can efficiently exploit waste heat and utilize solar or geothermal heat energy for electrical power generation. We demonstrate a novel technique exploiting water's large coefficient of thermal expansion, wherein modest thermal gradients produce the requisite high pressure for driving fast-flowing liquid water microjets, which can effect the direct conversion of the kinetic energy into electricity and gaseous hydrogen. Waste heat in thermoelectric generating plants and combustion engines, as well as solar and geothermal energy could be used to drive these systems.

  10. Phase-change thermal energy storage: Final subcontract report

    SciTech Connect

    Not Available

    1989-11-01

    The research and development described in this document was conducted within the US Department of Energy's Solar Thermal Technology Program. The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axes tracking mirrors) to focus the sun's radiant energy onto a single, tower-mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating working fluid. Receiver temperatures range from 100{degree}C in low-temperature troughs to over 1500{degree}C in dish and central receiver systems. 12 refs., 119 figs., 4 tabs.

  11. Development of a wind energy climate service based on seasonal climate prediction

    NASA Astrophysics Data System (ADS)

    Torralba, Veronica; Doblas-Reyes, Francisco J.; Cortesi, Nicola; Christel, Isadora; González-Reviriego, Nube; Turco, Marco; Soret, Albert

    2016-04-01

    Climate predictions tailored to the wind energy sector represent an innovation to better understand the future variability of wind energy resources. At seasonal time scales current energy practices employ a simple approach based on a retrospective climatology. Instead, probabilistic climate forecasting can better address specific decisions that affect energy demand and supply, as well as decisions relative to the planning of maintenance work. Here we illustrate the advantages that seasonal climate predictions might offer to a wide range of users and discuss the best way to provide them with this information. We use the predictions of 10-meter wind speed from the ECMWF seasonal forecast System 4 (S4). S4, as every operational seasonal forecast system, is affected by a range of biases. Hence, to produce usable climate information from the predictions, different bias-adjustment techniques and downscaling methods should be applied, their choice depending on the user requirements. An ensemble of post-processing methods is described, and their relative merit evaluated as a function of their impact of the characteristics of the forecast error and the usability of the resulting forecasts. Both reanalyses (ERA-Interim, JRA-55, MERRA) and in-situ observations are used as observational references. As an illustration of the downstream impact of the forecasts as a source of climate information, the post-processed seasonal predictions of wind speed will be used as input in a transfer model that translates climate information into generated power at different spatial scales.

  12. High Density Thermal Energy Storage with Supercritical Fluids

    NASA Technical Reports Server (NTRS)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  13. Guide to Setting Thermal Comfort Criteria and Minimizing Energy Use in Delivering Thermal Comfort

    SciTech Connect

    Regnier, Cindy

    2012-08-01

    Historically thermal comfort in buildings has been controlled by simple dry bulb temperature settings. As we move into more sophisticated low energy building systems that make use of alternate systems such as natural ventilation, mixed mode system and radiant thermal conditioning strategies, a more complete understanding of human comfort is needed for both design and control. This guide will support building designers, owners, operators and other stakeholders in defining quantifiable thermal comfort parameters?these can be used to support design, energy analysis and the evaluation of the thermal comfort benefits of design strategies. This guide also contains information that building owners and operators will find helpful for understanding the core concepts of thermal comfort. Whether for one building, or for a portfolio of buildings, this guide will also assist owners and designers in how to identify the mechanisms of thermal comfort and space conditioning strategies most important for their building and climate, and provide guidance towards low energy design options and operations that can successfully address thermal comfort. An example of low energy design options for thermal comfort is presented in some detail for cooling, while the fundamentals to follow a similar approach for heating are presented.

  14. Thermal Energy Corporation in Houston, Texas Earns ENERGY STAR Award for Carbon Pollution Reductions

    EPA Pesticide Factsheets

    DALLAS - (June 29, 2015) The U.S. Environmental Protection Agency (EPA) recently recognized Thermal Energy Corporation (TECO) of Houston, Texas with the ENERGY STAR Combined Heat and Power (CHP) Award. TECO substantially reduced emissions of carbon

  15. 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.

  16. 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

  17. Can we predict solar radiation at seasonal time-scale over Europe? A renewable energy perspective.

    NASA Astrophysics Data System (ADS)

    De Felice, Matteo; Alessandri, Andrea

    2015-04-01

    Surface solar radiation can be an important variable for the activities related to renewable energies (photovoltaic) and agriculture. Having accurate forecast may be of potential use for planning and operational tasks. This study examines the predictability of seasonal surface solar radiation comparing ECMWF System4 Seasonal operational forecasts with reanalyses (ERA-INTERIM, MERRA) and other datasets (NASA/GEWEX SRB, WFDEI). This work is focused on the period 1984-2007 and it tries to answer the following questions: 1) How similar are the chosen datasets looking at average and interannual variability? 2) What is the skill of seasonal forecasts in predicting solar radiation? 3) Is it useful for solar power operations and planning the seasonal prediction of solar radiation? It is important to assess the capability of climate datasets in describing surface solar radiation but at the same time it is critical to understand the needs of solar power industry in order to find the right problems to tackle.

  18. The Effect of Seasonal Thermal Stress on Lipid Mobilisation, Antioxidant Status and Reproductive Performance in Dairy Cows.

    PubMed

    Turk, R; Podpečan, O; Mrkun, J; Flegar-Meštrić, Z; Perkov, S; Zrimšek, P

    2015-08-01

    Heat stress is a major factor contributing to low fertility of dairy cows with a great economic impact in dairy industry. Heat-stressed dairy cows usually have reduced nutrient intake, resulting in a higher degree of negative energy balance (NEB). The aim of this study was to investigate the seasonal thermal effect on lipid metabolism, antioxidant activity and reproductive performance in dairy cows. Thirty-two healthy dairy heifers were included in the study. According to the ambient temperature, animals were divided into two groups: winter (N = 14) and summer season (N = 18). Metabolic parameters, paraoxonase-1 (PON1) activity and total antioxidant status (TAS) were monitored at the time of insemination (basal values) and from 1 week before until 8 weeks after calving. Number of services per conception and calving-to-conception (CC) interval were calculated from the farm recording data. Serum triglyceride, non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) concentrations were significantly increased after calving in summer compared to winter, indicating higher degree of NEB in cows during summer. PON1 activity was significantly decreased after calving in both summer and winter group. TAS concentration was significantly lower in summer than that in winter. A significantly higher number of services were needed for conception in summer compared to winter, and CC interval was significantly longer in summer than that in winter as well. Additionally, reproductive performance significantly correlated with the severity of NEB, suggesting that lipid mobilization and lower antioxidant status contributed to poor reproduction ability in dairy cows during hot months.

  19. Thermal effects on isoscalar giant resonance energies in hot nuclei

    SciTech Connect

    Wen, W.; Dai, G.; Jin, G.

    1995-07-01

    The thermal effects on the energies of the isoscalar giant multipole resonances of hot nuclei are discussed and an approximate formula for the energy as a function of temperature is derived via a hydrodynamic theory. The energy difference between the isoscalar giant multipole resonance of a hot nucleus and its ground-state resonance depends on the competition between the volume expansion and the increase of the average kinetic energy per nucleon of hot nuclei, which lower and raise the resonance energy, respectively, and nearly counteract each other in magnitude. The variaiton of the isoscalar giant resonance energy with temperature is very small.

  20. Environmental assessment of the potential effects of aquifer thermal energy storage systems on microorganisms in groundwater

    SciTech Connect

    Hicks, R.J.; Stewart, D.L.

    1988-03-01

    The primary objective of this study was to evaluate the potential environmental effects (both adverse and beneficials) of aquifer thermal energy storage (ATES) technology pertaining to microbial communities indigenous to subsurface environments (i.e., aquifers) and the propagation, movement, and potential release of pathogenic microorganisms (specifically, Legionella) within ATES systems. Seasonal storage of thermal energy in aquifers shows great promise to reduce peak demand; reduce electric utility load problems; contribute to establishing favorable economics for district heating and cooling systems; and reduce pollution from extraction, refining, and combustion of fossil fuels. However, concerns that the widespread implementation of this technology may have adverse effects on biological systems indigeneous to aquifers, as well as help to propagate and release pathogenic organisms that enter thee environments need to be resolved. 101 refs., 2 tabs.

  1. ENERGY PARTITIONS AND EVOLUTION IN A PURELY THERMAL SOLAR FLARE

    SciTech Connect

    Fleishman, Gregory D.; Nita, Gelu M.; Gary, Dale E.

    2015-04-01

    This paper presents a solely thermal flare, which we detected in the microwave range from the thermal gyro- and free–free emission it produced. An advantage of analyzing thermal gyro emission is its unique ability to precisely yield the magnetic field in the radiating volume. When combined with observationally deduced plasma density and temperature, these magnetic field measurements offer a straightforward way of tracking evolution of the magnetic and thermal energies in the flare. For the event described here, the magnetic energy density in the radio-emitting volume declines over the flare rise phase, then stays roughly constant during the extended peak phase, but recovers to the original level over the decay phase. At the stage where the magnetic energy density decreases, the thermal energy density increases; however, this increase is insufficient, by roughly an order of magnitude, to compensate for the magnetic energy decrease. When the magnetic energy release is over, the source parameters come back to nearly their original values. We discuss possible scenarios to explain this behavior.

  2. Magneto-Thermo-Triboelectric Generator (MTTG) for thermal energy harvesting

    NASA Astrophysics Data System (ADS)

    Jang, Kwang Yeop; Lee, James; Lee, Dong-Gun

    2016-04-01

    We present a novel thermal energy harvesting system using triboelectric effect. Recently, there has been intensive research efforts on energy harvesting using triboelectric effect, which can produce surprising amount of electric power (when compared to piezoelectric materials) by rubbing or touching (i.e, electric charge by contact and separation) two different materials together. Numerous studies have shown the possibility as an attractive alternative with good transparency, flexibility and low cost abilities for its use in wearable device and smart phone applications markets. However, its application has been limited to only vibration source, which can produce sustained oscillation with maintaining contact and separation states repeatedly for triboelectric effect. Thus, there has been no attempt toward thermal energy source. The proposed approach can convert thermal energy into electricity by pairing triboelectric effect and active ferromagnetic materials The objective of the research is to develop a new manufacturing process of design, fabrication, and testing of a Magneto-Thermo-Triboelectric Generator (MTTG). The results obtained from the approach show that MTTG devices have a feasible power energy conversion capability from thermal energy sources. The tunable design of the device is such that it has efficient thermal capture over a wide range of operation temperature in waste heat.

  3. Engineering evaluation of a sodium hydroxide thermal energy storage module

    NASA Technical Reports Server (NTRS)

    Perdue, D. G.; Gordon, L. H.

    1980-01-01

    An engineering evaluation of thermal energy storage prototypes was performed in order to assess the development status of latent heat storage media. The testing and the evaluation of a prototype sodium hydroxide module is described. This module stored off-peak electrical energy as heat for later conversion to domestic hot water needs.

  4. Ocean thermal energy conversion: report to congress - fiscal year 1982

    SciTech Connect

    Not Available

    1983-03-31

    National Oceanic and Atmospheric Administration (NOAA) activities related to ocean thermal energy conversion (OTEC) during fiscal year 1982 are described. The agency focus has been in the areas of providing ocean engineering and technical assistance to the Department of Energy (DOE), in streamlining the administration of the Federal OTEC licensing system, and in environmental assistance.

  5. Energy Aspects of Thermal Molecular Switching: Molecular Thermal Hysteresis of Helicene Oligomers.

    PubMed

    Shigeno, Masanori; Kushida, Yo; Yamaguchi, Masahiko

    2015-07-20

    Molecular switching is a phenomenon by which a molecule reversibly changes its structure and state in response to external stimuli or energy. Herein, molecular switching is discussed from thermodynamic and kinetic aspects in terms of energy supply with an emphasis on the thermal switching exhibited by helicene oligomers. It includes the inversion of relative thermodynamic stability induced by temperature changes and molecular thermal hysteresis in a closed system. The thermal phenomenon associated with the oligomers involves population/concentration changes between metastable states under nonequilibrium thermodynamic control.

  6. Thermal conductor for high-energy electrochemical cells

    DOEpatents

    Hoffman, Joseph A.; Domroese, Michael K.; Lindeman, David D.; Radewald, Vern E.; Rouillard, Roger; Trice, Jennifer L.

    2000-01-01

    A thermal conductor for use with an electrochemical energy storage device is disclosed. The thermal conductor is attached to one or both of the anode and cathode contacts of an electrochemical cell. A resilient portion of the conductor varies in height or position to maintain contact between the conductor and an adjacent wall structure of a containment vessel in response to relative movement between the conductor and the wall structure. The thermal conductor conducts current into and out of the electrochemical cell and conducts thermal energy between the electrochemical cell and thermally conductive and electrically resistive material disposed between the conductor and the wall structure. The thermal conductor may be fabricated to include a resilient portion having one of a substantially C-shaped, double C-shaped, Z-shaped, V-shaped, O-shaped, S-shaped, or finger-shaped cross-section. An elastomeric spring element may be configured so as to be captured by the resilient conductor for purposes of enhancing the functionality of the thermal conductor. The spring element may include a protrusion that provides electrical insulation between the spring conductor and a spring conductor of an adjacently disposed electrochemical cell in the presence of relative movement between the cells and the wall structure. The thermal conductor may also be fabricated from a sheet of electrically conductive material and affixed to the contacts of a number of electrochemical cells.

  7. Study of thermal energy storage using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Weast, T. E.; Shannon, L. J.; Ananth, K. P.

    1980-01-01

    The technical and economic feasibility of fluid bed heat exchangers (FBHX) for thermal energy storage (TES) in waste heat recovery applications is assessed by analysis of two selected conceptual systems, the rotary cement kiln and the electric arc furnace. It is shown that the inclusion of TES in the energy recovery system requires that the difference in off-peak and on-peak energy rates be large enough so that the value of the recovered energy exceeds the value of the stored energy by a wide enough margin to offset parasitic power and thermal losses. Escalation of on-peak energy rates due to fuel shortages could make the FBHX/TES applications economically attractive in the future.

  8. Seasonal carcass composition and energy balance of female black ducks in Maine

    USGS Publications Warehouse

    Reinecke, K.J.; Stone, T.L.; Owen, R.B.

    1982-01-01

    Female Black Ducks (Anas rubripes) collected in Maine during the summer, fall, and winter of 1974-1976 showed significant seasonal variation in body weight, nonfat dry weight, gizzard and pectoral muscle weight, and fat, moisture, and protein content. Variation of body weight within and among seasons was correlated more strongly with carcass protein content, and with fat content during seasons of heavy lipid deposition, than with three structural size variables (culmen, tarsus, and sternum). Regression equations including fat and protein as independent variables accounted for 80-90% of the annual and seasonal variation in body weight; structural size variables alone accounted for less than 30%. Immature females averaged 54 and 99 g lighter, and carried 54 and 59 g less fat than adults during the fall and winter. Ducks of both age classes lost weight in December and January. Adult and immature females metabolized 59 and 64 g of fat and 17 and 25 g of protein in winter compared with 46 g of fat during the nesting season. Nutrient reserves are thus equally as important for the winter survival of these birds as for successfurl eproduction. Seasonal changes in carcass composition suggest that (1) fat deposited in late fall provides an energy reserve during winter, (2) a reduction in lean weight during winter may lower daily energy requirements and increase the effective amount of energy reserves, and (3) declining body weights during late winter may be an endogenous rhythm that reflects a shift in the expected benefits of an energy reserve compared to the costs of carrying additional weight,

  9. Intercomparison of the seasonal cycle in 200 hPa kinetic energy in AMIP GCM simulations

    SciTech Connect

    Boyle, J.S.

    1996-10-01

    The 200 hPa kinetic energy is represented by means of the spherical harmonic components for the Atmospheric Model Intercomparison Project (AMIP) simulations, the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis and the European Centre for Medium Range Weather Forecast Reanalysis (ERA). The data used are the monthly mean wind fields from 1979 to 1988. The kinetic energy is decomposed into the divergent (DKE) and rotational (RKE) components and emphasis is placed on examining the former. The two reanalysis data sets show reasonable agreement that is best for the rotational kinetic energy. The largest difference in the divergent kinetic energy occurs during the northern summer. As might be expected, the two analyses are closet in regions where there are sufficient observations such that the effect of the model used in the assimilation cycle are minimized. The observed RKE show only a slight seasonal cycle with a maximum occuring during the northern winter. The DKE, on the other hand, has a very pronounced seasonal cycle with maxima at the solsticial seasons and minima during the equinoctial seasons. The model results show a very large spread in the magnitudes of the RKE and DKE although the models all evince a seasonal variation in phase with that observed. The median values of the seasonal cycle of RKE and DKE for the models are usually superior to those of any individual model. Results are also presented for simulation following the AMIP protocol but using updated versions of the original AMIP entries. In most cases these new integrations show better agreement with the observations.

  10. Solar thermal parabolic dish energy applications

    NASA Technical Reports Server (NTRS)

    Pijawka, W.

    1981-01-01

    Vu-graphs are presented that show that applications are a viable distributed renewable power generation option. Quality energy can be produced in the form of electricity and high temperature heat. Modular systems are described that can be distributed to new or existing plants and that are mass producible with the associated economies of production.

  11. Seasonality of energy expenditure during pregnancy and lactation for rural Nepali women.

    PubMed

    Panter-Brick, C

    1993-05-01

    Total energy expenditure (TEE) was estimated for 19 nonpregnant, nonlactating (NPNL) and 24 pregnant (P) or lactating (L) women from 3601 h of minute-by-minute observation and 168 measurements of the energy cost of activities. NPNL women significantly increased subsistence activity and TEE from 9.9 MJ [1.89 x basal metabolic rate (BMR)] in the winter to 10.5 MJ (2.01 x BMR) in the monsoon season. There were differences between NPNL,P, and L women in the winter, but not in the spring or monsoon season when all individuals sustained very heavy physical activity. High TEE values resulted from spending very long hours in tasks that, although appearing physically demanding to the casual observer, were characterized by light or moderate energy cost. The study highlights the importance of seasonal constraints on women's work, which prevent P and L women from significantly curtailing physical activity during the monsoon season, and which effectively limit the scope of behavioral mechanisms for saving energy and reducing TEE.

  12. Phytochemical profiles and health-promoting effects of cool-season food legumes as influenced by thermal processing.

    PubMed

    Xu, Baojun; Chang, Sam K C

    2009-11-25

    The effects of four thermal processing methods (conventional boiling, conventional steaming, pressure boiling, and pressure steaming) on phytochemical profiles, antioxidant capacities, and antiproliferation properties of commonly consumed cool-season food legumes, including green pea, yellow pea, chickpea, and lentil, were investigated. Four groups of individual phenolic compounds, including phenolic acids, anthocyanins, and flavan-3-ols, as well as flavonols and flavones were quantified using HPLC, respectively. As compared to the original raw legumes, all processing methods caused significant (p<0.05) reduction in total phenolic content, procyanidin content, total saponin content, phytic acid content, chemical antioxidant capacities in terms of ferric reducing antioxidant power and peroxyl radical scavenging capacity, and cellular antioxidant activity as well as antiproliferation capacities of cool-season food legumes. Different cooking methods have varied effects on reducing total phenolics, saponins, phytic acids, and individual phenolic compounds. For all cool-season food legumes, steaming appeared to be a better cooking method than boiling in retaining antioxidants and phenolic components, whereas boiling appeared to be effective in reducing saponin and phytic acid contents. In the case of lentil, all thermal processing methods (except conventional steaming) caused significant (p<0.05) decreases in gallic, chlorogenic, p-coumaric, sinapic, subtotal benzoic, subtotal cinnamic acid, and total phenolic acid. All thermal processing methods caused significant (p<0.05) decreases in (+)-catechin and flavan-3-ols in each cool-season food legume.

  13. Leptin levels, seasonality and thermal acclimation in the Microbiotherid marsupial Dromiciops gliroides: Does photoperiod play a role?

    PubMed

    Franco, Marcela; Contreras, Carolina; Place, Ned J; Bozinovic, Francisco; Nespolo, Roberto F

    2017-01-01

    Mammals of the Neotropics are characterized by a marked annual cycle of activity, which is accompanied by several physiological changes at the levels of the whole organism, organs and tissues. The physiological characterization of these cycles is important, as it gives insight on the mechanisms by which animals adjust adaptively to seasonality. Here we studied the seasonal changes in blood biochemical parameters in the relict South American marsupial Dromiciops gliroides ("monito del monte" or "little mountain monkey"), under semi-natural conditions. We manipulated thermal conditions in order to characterize the effects of temperature and season on a battery of biochemical parameters, body mass and adiposity. Our results indicate that monitos experience an annual cycle in body mass and adiposity (measured as leptin levels), reaching a maximum in winter and a minimum in summer. Blood biochemistry confirms that the nutritional condition of animals is reduced in summer instead of winter (as generally reported). This was coincident with a reduction of several biochemical parameters in summer, such as betahydroxybutyrate, cholesterol, total protein concentration and globulins. Monitos seem to initiate winter preparation during autumn and reach maximum body reserves in winter. Hibernation lasts until spring, at which time they use fat reserves and become reproductively active. Sexual maturation during summer would be the strongest energetic bottleneck, which explains the reductions in body mass and other parameters in this season. Overall, this study suggests that monitos anticipate the cold season by a complex interaction of photoperiodic and thermal cues.

  14. Central unresolved issues in thermal energy storage for building heating and cooling

    SciTech Connect

    Swet, C.J.; Baylin, F.

    1980-07-01

    This document explores the frontier of the rapidly expanding field of thermal energy storage, investigates unresolved issues, outlines research aimed at finding solutions, and suggests avenues meriting future research. Issues related to applications include value-based ranking of storage concepts, temperature constraints, consistency of assumptions, nomenclature and taxonomy, and screening criteria for materials. Issues related to technologies include assessing seasonal storage concepts, diurnal coolness storage, selection of hot-side storage concepts for cooling-only systems, phase-change storage in building materials, freeze protection for solar water heating systems, and justification of phase-change storage for active solar space heating.

  15. Metal hydrides for concentrating solar thermal power energy storage

    NASA Astrophysics Data System (ADS)

    Sheppard, D. A.; Paskevicius, M.; Humphries, T. D.; Felderhoff, M.; Capurso, G.; Bellosta von Colbe, J.; Dornheim, M.; Klassen, T.; Ward, P. A.; Teprovich, J. A.; Corgnale, C.; Zidan, R.; Grant, D. M.; Buckley, C. E.

    2016-04-01

    The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed.

  16. Alcan's ocean thermal energy conversion (OTEC) program

    SciTech Connect

    Hron, V.; Fitzpatrick, N.P. ); Hay, E. ); Johnson, F.A. )

    1991-01-01

    Since 1985 Alcan has been operating equipment at a test site at the National Energy Laboratory of Hawaii at Keahole Point near Kona in Hawaii. Segments of aluminum heat exchangers are exposed to surface sea water at 27{degrees} C and to water from 2000 ft down coming in at 7{degrees} C. Progress was such that in 1988 Alcan contracted GEC to design a 250 kW pilot facility. The cold deep water, suitable for air conditioning, is rich in nutrients and the hierarchy of mariculture products one might select is outlined. This paper reports that closed-cycle OTEC may be economical, practical and capable of having a significant impact upon world energy needs. It can be implemented on a small scale using revenues derived from fresh water production and mariculture.

  17. Micro rectennas: Brownian ratchets for thermal-energy harvesting

    SciTech Connect

    Pan, Y.; Powell, C. V.; Balocco, C.; Song, A. M.

    2014-12-22

    We experimentally demonstrated the operation of a rectenna for harvesting thermal (blackbody) radiation and converting it into dc electric power. The device integrates an ultrafast rectifier, the self-switching nanodiode, with a wideband log-periodic spiral microantenna. The radiation from the thermal source drives the rectenna out of thermal equilibrium, permitting the rectification of the excess thermal fluctuations from the antenna. The power conversion efficiency increases with the source temperatures up to 0.02% at 973 K. The low efficiency is attributed mainly to the impedance mismatch between antenna and rectifier, and partially to the large field of view of the antenna. Our device not only opens a potential solution for harvesting thermal energy but also provides a platform for experimenting with Brownian ratchets.

  18. Minimum daily core body temperature in western grey kangaroos decreases as summer advances: a seasonal pattern, or a direct response to water, heat or energy supply?

    PubMed

    Maloney, Shane K; Fuller, Andrea; Meyer, Leith C R; Kamerman, Peter R; Mitchell, Graham; Mitchell, Duncan

    2011-06-01

    Using implanted temperature loggers, we measured core body temperature in nine western grey kangaroos every 5 min for 24 to 98 days in spring and summer. Body temperature was highest at night and decreased rapidly early in the morning, reaching a nadir at 10:00 h, after ambient temperature and solar radiation had begun to increase. On hotter days, the minimum morning body temperature was lower than on cooler days, decreasing from a mean of 36.2°C in the spring to 34.0°C in the summer. This effect correlated better with the time of the year than with proximate thermal stressors, suggesting that either season itself or some factor correlated with season, such as food availability, caused the change. Water saving has been proposed as a selective advantage of heterothermy in other large mammals, but in kangaroos the water savings would have been small and not required in a reserve with permanent standing water. We calculate that the lower core temperature could provide energy savings of nearly 7%. It is likely that the heterothermy that we observed on hot days results either from decreased energy intake during the dry season or from a seasonal pattern entrained in the kangaroos that presumably has been selected for because of decreased energy availability during the dry season.

  19. Buffer thermal energy storage for a solar Brayton engine

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    A study has been completed on the application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine. To aid in the study, a computer program was written for complete transient/stead-state Brayton cycle performance. The results indicated that thermal storage can afford a significant decrease in the number of engine shutdowns as compared to operating without thermal storage. However, the number of shutdowns does not continuously decrease as the storage material weight increases. In fact, there appears to be an optimum weight for minimizing the number of shutdowns.

  20. Thermal energy storage technical progress report, April 1992--March 1993

    SciTech Connect

    Olszewski, M.

    1993-05-01

    The Department of Energy (DOE) is supporting development of thermal energy storage (TES) as a means of efficiently coupling energy supplies to variable heating or cooling demands. Uses of TES include electrical demand-side management in buildings and industry, extending the utilization of renewable energy resources such as solar, and recovery of waste heat from periodic industrial processes. Technical progress to develop TES for specific diurnal and industrial applications under the Oak Ridge National Laboratory`s TES program from April 1992 to March 1993 is reported and covers research in the areas of low temperature sorption, thermal energy storage water heater, latent heat storage wallboard and latent/sensible heat regenerator technology development.

  1. Thermal environment in eight low-energy and twelve conventional Finnish houses.

    PubMed

    Kähkönen, Erkki; Salmi, Kari; Holopainen, Rauno; Pasanen, Pertti; Reijula, Kari

    2015-11-01

    We assessed the thermal environment of eight recently built low-energy houses and twelve conventional Finnish houses. We monitored living room, bedroom and outdoor air temperatures and room air relative humidity from June 2012 to September 2013. Perceived thermal environment was evaluated using a questionnaire survey during the heating, cooling and interim seasons. We compared the measured and perceived thermal environments of the low-energy and conventional houses. The mean air temperature was 22.8 °C (21.9-23.8 °C) in the low-energy houses, and 23.3 °C (21.4-26.5 °C) in the conventional houses during the summer (1. June 2013-31. August 2013). In the winter (1. December 2012-28. February 2013), the mean air temperature was 21.3 °C (19.8-22.5 °C) in the low-energy houses, and 21.6 °C (18.1-26.4 °C) in the conventional houses. The variation of the air temperature was less in the low-energy houses than that in the conventional houses. In addition, the occupants were on average slightly more satisfied with the indoor environment in the low-energy houses. However, there was no statistically significant difference between the mean air temperature and relative humidity of the low-energy and conventional houses. Our measurements and surveys showed that a good thermal environment can be achieved in both types of houses.

  2. Pyroelectric energy harvesting using liquid-based switchable thermal interfaces

    SciTech Connect

    Cha, G; Ju, YS

    2013-01-15

    The pyroelectric effect offers an intriguing solid-state approach for harvesting ambient thermal energy to power distributed networks of sensors and actuators that are remotely located or otherwise difficult to access. There have been, however, few device-level demonstrations due to challenges in converting spatial temperature gradients into temporal temperature oscillations necessary for pyroelectric energy harvesting. We demonstrate the feasibility of a device concept that uses liquid-based thermal interfaces for rapid switching of the thermal conductance between a pyroelectric material and a heat source/sink and can thereby deliver high output power density. Using a thin film of a pyroelectric co-polymer together with a macroscale mechanical actuator, we operate pyroelectric thermal energy harvesting cycles at frequencies close to 1 Hz. Film-level power densities as high as 110 mW/cm(3) were achieved, limited by slow heat diffusion across a glass substrate. When combined with a laterally interdigitated electrode array and a MEMS actuator, the present design offers an attractive option for compact high-power density thermal energy harvesters. (C) 2012 Elsevier B.V. All rights reserved.

  3. Descriptive analysis of aquifer thermal energy storage systems

    SciTech Connect

    Reilly, R.W.

    1980-06-01

    The technical and economic feasibility of large-scale aquifer thermal energy storage (ATES) was examined. A key to ATESs attractiveness is its simplicity of design and construction. The storage device consists of two ordinary water wells drilled into an aquifer, connected at the surface by piping and a heat exchanger. During the storage cycle water is pumped out of the aquifer, through the heat exchanger to absorb thermal energy, and then back down into the aquifer through the second well. The thermal storage remains in the aquifer storage bubble until required for use, when it is recovered by reversing the storage operation. For many applications the installation can probably be designed and constructed using existing site-specific information and modern well-drilling techniques. The potential for cost-effective implementation of ATES was investigated in the Twin Cities District Heating-Cogeneration Study in Minnesota. In the study, ATES demonstrated a net energy saving of 32% over the nonstorage scenario, with an annual energy cost saving of $31 million. Discounting these savings over the life of the project, the authors found that the break-even capital cost for ATES construction was $76/kW thermal, far above the estimated ATES development cost of $23 to 50/kW thermal. It appears tht ATES can be highly cost effective as well as achieve substantial fuel savings. ATES would be environmentally beneficial and could be used in many parts of the USA. The existing body of information on ATES indicates that it is a cost-effective, fuel-conserving technique for providing thermal energy for residential, commercial, and industrial users. The negative aspects are minor and highly site-specific, and do not seem to pose a threat to widespread commercialization. With a suitable institutional framework, ATES promises to supply a substantial portion of the nation's future energy needs. (LCL)

  4. Seasonal variations in the energy budget of Elliot's pheasant (Syrmaticus ellioti) in cage.

    PubMed

    Luo, Ying; Yu, Tai-Lin; Huang, Cheng-Ming; Zhao, Tong; Li, Han-Hua; Li, Chang-Jian

    2013-01-01

    This study aimed to discuss the energy budget of Elliot's pheasant Syrmaticus ellioti in different seasons, with life and health, good growth and normal digestion of Elliot's pheasant as the tested objects, The energy budget of Elliot's pheasant was measured by daily collection of the trial pheasants' excrement in the biological garden of Guangxi Normal University from March 2011 to February 2012. The results showed that the gross energy consumption, metabolic energy and excrement energy varied by season, increasing as temperature decreased. There was significant difference in gross energy consumption, metabolic energy, excrement energy between adults and nonages. There was also a trend that food digestibility of pheasants increases as temperature increases. In the same season, the food digestibility of adults was better than that of nonages. Throughout spring, summer, autumn and winter, the metabolic energy of 4-year adults were 305.77±13.40 kJ/d, 263.67±11.89 kJ/d, 357.23±25.49 kJ/d and 403.12±24.91 kJ/d, respectively, and the nonages were 284.86±17.22 kJ/d, 284. 66±15.16 kJ/d, 402. 26±31.46 kJ/d and 420. 30±31.98 kJ/d, respectively. The minimum metabolic energies were 247.65±21.81 g, 265.86±26.53 g, respectively for each group, detected between 4-year adults and 1-year nonages. Further study is needed to determine whether 29.6 C is the optimal temperature for the Elliot's pheasant.

  5. Phase change thermal storage for a solar total energy system

    NASA Technical Reports Server (NTRS)

    Rice, R. E.; Cohen, B. M.

    1978-01-01

    An analytical and experimental program is being conducted on a one-tenth scale model of a high-temperature (584 K) phase-change thermal energy storage system for installation in a solar total energy test facility at Albuquerque, New Mexico, U.S.A. The thermal storage medium is anhydrous sodium hydroxide with 8% sodium nitrate. The program will produce data on the dynamic response of the system to repeated cycles of charging and discharging simulating those of the test facility. Data will be correlated with a mathematical model which will then be used in the design of the full-scale system.

  6. Seasonal energy storage system based on hydrogen for self sufficient living

    NASA Astrophysics Data System (ADS)

    Bielmann, M.; Vogt, U. F.; Zimmermann, M.; Züttel, A.

    SELF is a resource independent living and working environment. By on-board renewable electricity generation and storage, it accounts for all aspects of living, such as space heating and cooking as well as providing a purified rainwater supply and wastewater treatment, excluding food supply. Uninterrupted, on-demand energy and water supply are the key challenges. Off-grid renewable power supply fluctuations on daily and seasonal time scales impose production gaps that have to be served by local storage, a function normally fulfilled by the grid. While daily variations only obligate a small storage capacity, requirements for seasonal storage are substantial. The energy supply for SELF is reviewed based on real meteorological data and demand patterns for Zurich, Switzerland. A battery system with propane for cooking serves as a reference for battery-only and hybrid battery/hydrogen systems. In the latter, hydrogen is used for cooking and electricity generation. The analysis shows that hydrogen is ideal for long term bulk energy storage on a seasonal timescale, while batteries are best suited for short term energy storage. Although the efficiency penalty from hydrogen generation is substantial, in off-grid systems, this parameter is tolerable since the harvesting ratio of photovoltaic energy is limited by storage capacity.

  7. Modeling Thermal and Environmental Effects of Prototype Scale Ocean Thermal Energy Conversion

    NASA Astrophysics Data System (ADS)

    Hamrick, J. M.

    2010-12-01

    Ocean thermal energy conversion (OTEC) utilizes the temperature difference between the mix lay and deep water electricity generation. The small temperature difference compared to other thermal-electric generation devises, typically between 20 and 25 C, requires the substantial volumetric flows on the order of hundreds of cubic meters per second to generate net energy and recover capital investments. This presentation described the use of a high resolution three-dimensional EFDC model with an embedded jet-plume model to simulate the thermal and environmental impacts of a number of prototype OTEC configurations on the southwest coast of Oahu, Hawaii. The EFDC model is one-way nested into a larger scale ROMS model to allow for realistic incorporation of region processes including external and internal tides and sub-tidal circulation. Impacts on local thermal structure and the potential for nutrient enrichment of the mixed layer are addressed with model and presented.

  8. Seasonal patterns in energy partitioning of two freshwater marsh ecosystems in the Florida Everglades

    NASA Astrophysics Data System (ADS)

    Malone, Sparkle L.; Staudhammer, Christina L.; Loescher, Henry W.; Olivas, Paulo; Oberbauer, Steven F.; Ryan, Michael G.; Schedlbauer, Jessica; Starr, Gregory

    2014-08-01

    We analyzed energy partitioning in short- and long-hydroperiod freshwater marsh ecosystems in the Florida Everglades by examining energy balance components (eddy covariance derived latent energy (LE) and sensible heat (H) flux). The study period included several wet and dry seasons and variable water levels, allowing us to gain better mechanistic information about the control of and changes in marsh hydroperiods. The annual length of inundation is ~5 months at the short-hydroperiod site (25°26'16.5″N, 80°35'40.68″W), whereas the long-hydroperiod site (25°33'6.72″N, 80°46'57.36″W) is inundated for ~12 months annually due to differences in elevation and exposure to surface flow. In the Everglades, surface fluxes feed back to wet season precipitation and affect the magnitude of seasonal change in water levels through water loss as LE (evapotranspiration (ET)). At both sites, annual precipitation was higher than ET (1304 versus 1008 at the short-hydroperiod site and 1207 versus 1115 mm yr-1 at the long-hydroperiod site), though there were seasonal differences in the ratio of ET:precipitation. Results also show that energy balance closure was within the range found at other wetland sites (60 to 80%) and was lower when sites were inundated (60 to 70%). Patterns in energy partitioning covaried with hydroperiods and climate, suggesting that shifts in any of these components could disrupt current water and biogeochemical cycles throughout the Everglades region. These results suggest that the complex relationships between hydroperiods, energy exchange, and climate are important for creating conditions sufficient to maintain Everglades ecosystems.

  9. Thermal energy storage technical progress report, April 1990--March 1991

    SciTech Connect

    Tomlinson, J.J.

    1992-03-01

    The Department of Energy (DOE) is supporting development of thermal energy storage (TES) as a means of efficiently coupling energy supplies to variable heating or cooling demands. Uses of TES include electrical demand-side management in buildings and industry, extending the utilization of renewable energy resources such as solar, and recovery of waste heat from periodic industrial processes. Technical progress to develop TES for specific diurnal and industrial applications under Oak Ridge National Laboratory`s TES program from April 1990 to March 1992 is reported and covers research in the areas of low temperature sorption, direct contact ice making, latent heat storage plasterboard and latent/sensible heat regenerator technology development.

  10. Thermal energy storage technical progress report, April 1990--March 1991

    SciTech Connect

    Tomlinson, J.J.

    1992-03-01

    The Department of Energy (DOE) is supporting development of thermal energy storage (TES) as a means of efficiently coupling energy supplies to variable heating or cooling demands. Uses of TES include electrical demand-side management in buildings and industry, extending the utilization of renewable energy resources such as solar, and recovery of waste heat from periodic industrial processes. Technical progress to develop TES for specific diurnal and industrial applications under Oak Ridge National Laboratory's TES program from April 1990 to March 1992 is reported and covers research in the areas of low temperature sorption, direct contact ice making, latent heat storage plasterboard and latent/sensible heat regenerator technology development.

  11. Conversion of concentrated solar thermal energy into chemical energy.

    PubMed

    Tamaura, Yutaka

    2012-01-01

    When a concentrated solar beam is irradiated to the ceramics such as Ni-ferrite, the high-energy flux in the range of 1500-2500 kW/m(2) is absorbed by an excess Frenkel defect formation. This non-equilibrium state defect is generated not by heating at a low heating-rate (30 K/min), but by irradiating high flux energy of concentrated solar beam rapidly at a high heating rate (200 K/min). The defect can be spontaneously converted to chemical energy of a cation-excess spinel structure (reduced-oxide form) at the temperature around 1773 K. Thus, the O(2) releasing reaction (α-O(2) releasing reaction) proceeds in two-steps; (1) high flux energy of concentrated solar beam absorption by formation of the non-equilibrium Frenkel defect and (2) the O(2) gas formation from the O(2-) in the Frenkel defect even in air atmosphere. The 2nd step proceeds without the solar radiation. We may say that the 1st step is light reaction, and 2nd step, dark reaction, just like in photosynthesis process.

  12. Ocean Thermal Energy Conversion Program Management Plan

    SciTech Connect

    Combs, R E

    1980-01-01

    The Office of the Associate Laboratory Director for Energy and Environmental Technology has established the OTEC Program Management Office to be responsible for the ANL-assigned tasks of the OTEC Program under DOE's Chicago Operations and Regional Office (DOE/CORO). The ANL OTEC Program Management Plan is essentially a management-by-objective plan. The principal objective of the program is to provide lead technical support to CORO in its capacity as manager of the DOE power-system program. The Argonne OTEC Program is divided into three components: the first deals with development of heat exchangers and other components of OTEC power systems, the second with development of biofouling counter-measures and corrosion-resistant materials for these components in seawater service, and the third with environmental and climatic impacts of OTEC power-system operation. The essential points of the Management Plan are summarized, and the OTEC Program is described. The organization of the OTEC Program at ANL is described including the functions, responsibilities, and authorities of the organizational groupings. The system and policies necessary for the support and control functions within the organization are discussed. These functions cross organizational lines, in that they are common to all of the organization groups. Also included are requirements for internal and external reports.

  13. Advanced phase change composite by thermally annealed defect-free graphene for thermal energy storage.

    PubMed

    Xin, Guoqing; Sun, Hongtao; Scott, Spencer Michael; Yao, Tiankai; Lu, Fengyuan; Shao, Dali; Hu, Tao; Wang, Gongkai; Ran, Guang; Lian, Jie

    2014-09-10

    Organic phase change materials (PCMs) have been utilized as latent heat energy storage and release media for effective thermal management. A major challenge exists for organic PCMs in which their low thermal conductivity leads to a slow transient temperature response and reduced heat transfer efficiency. In this work, 2D thermally annealed defect-free graphene sheets (GSs) can be obtained upon high temperature annealing in removing defects and oxygen functional groups. As a result of greatly reduced phonon scattering centers for thermal transport, the incorporation of ultralight weight and defect free graphene applied as nanoscale additives into a phase change composite (PCC) drastically improve thermal conductivity and meanwhile minimize the reduction of heat of fusion. A high thermal conductivity of the defect-free graphene-PCC can be achieved up to 3.55 W/(m K) at a 10 wt % graphene loading. This represents an enhancement of over 600% as compared to pristine graphene-PCC without annealing at a comparable loading, and a 16-fold enhancement than the pure PCM (1-octadecanol). The defect-free graphene-PCC displays rapid temperature response and superior heat transfer capability as compared to the pristine graphene-PCC or pure PCM, enabling transformational thermal energy storage and management.

  14. Efficient thermal energy harvesting using nanoscale magnetoelectric heterostructures

    NASA Astrophysics Data System (ADS)

    Etesami, S. R.; Berakdar, J.

    2016-02-01

    Thermomechanical cycles with a ferroelectric working substance convert heat to electrical energy. As shown here, magnetoelectrically coupled ferroelectric/ferromagnetic composites (also called multiferroics) allow for an efficient thermal energy harvesting at room temperature by exploiting the pyroelectric effect. By virtue of the magnetoelectric coupling, external electric and magnetic fields can steer the operation of these heat engines. Our theoretical predictions are based on a combination of Landau-Khalatnikov-Tani approach (with a Ginzburg-Landau-Devonshire potential) to simulate the ferroelectric dynamics coupled to the magnetic dynamics. The latter is treated via the electric-polarization-dependent Landau-Lifshitz-Gilbert equation. By performing an adapted Olsen cycle we show that a multiferroic working substance is potentially much more superior to the sole ferroelectrics, as far as the thermal energy harvesting using pyroelectric effect is concerned. Our proposal holds promise not only for low-energy consuming devices but also for cooling technology.

  15. Research and development on ocean thermal energy conversion in Japan

    SciTech Connect

    Uehara, H.

    1982-08-01

    The study of Ocean Thermal Energy Conversion (OTEC) in Japan has been conducted under the leadership of a team of the ''Sunshine Project'', a national new energy development project promoted by the Ministry of International Trade and Industries (MITI) since 1974. At present, two experimental OTEC power plants -Nauru's OTEC plant and Imari's OTEC plant are operating. In this paper, the review of research and development activity of these two OTEC plants in Japan is made.

  16. High temperature latent heat thermal energy storage to augment solar thermal propulsion for microsatellites

    NASA Astrophysics Data System (ADS)

    Gilpin, Matthew R.

    Solar thermal propulsion (STP) offers an unique combination of thrust and efficiency, providing greater total DeltaV capability than chemical propulsion systems without the order of magnitude increase in total mission duration associated with electric propulsion. Despite an over 50 year development history, no STP spacecraft has flown to-date as both perceived and actual complexity have overshadowed the potential performance benefit in relation to conventional technologies. The trend in solar thermal research over the past two decades has been towards simplification and miniaturization to overcome this complexity barrier in an effort finally mount an in-flight test. A review of micro-propulsion technologies recently conducted by the Air Force Research Laboratory (AFRL) has identified solar thermal propulsion as a promising configuration for microsatellite missions requiring a substantial Delta V and recommended further study. A STP system provides performance which cannot be matched by conventional propulsion technologies in the context of the proposed microsatellite ''inspector" requiring rapid delivery of greater than 1500 m/s DeltaV. With this mission profile as the target, the development of an effective STP architecture goes beyond incremental improvements and enables a new class of microsatellite missions. Here, it is proposed that a bi-modal solar thermal propulsion system on a microsatellite platform can provide a greater than 50% increase in Delta V vs. chemical systems while maintaining delivery times measured in days. The realization of a microsatellite scale bi-modal STP system requires the integration of multiple new technologies, and with the exception of high performance thermal energy storage, the long history of STP development has provided "ready" solutions. For the target bi-modal STP microsatellite, sensible heat thermal energy storage is insufficient and the development of high temperature latent heat thermal energy storage is an enabling

  17. Semi-transparent solar energy thermal storage device

    DOEpatents

    McClelland, John F.

    1985-06-18

    A visually transmitting solar energy absorbing thermal storage module includes a thermal storage liquid containment chamber defined by an interior solar absorber panel, an exterior transparent panel having a heat mirror surface substantially covering the exterior surface thereof and associated top, bottom and side walls, Evaporation of the thermal storage liquid is controlled by a low vapor pressure liquid layer that floats on and seals the top surface of the liquid. Porous filter plugs are placed in filler holes of the module. An algicide and a chelating compound are added to the liquid to control biological and chemical activity while retaining visual clarity. A plurality of modules may be supported in stacked relation by a support frame to form a thermal storage wall structure.

  18. Semi-transparent solar energy thermal storage device

    DOEpatents

    McClelland, John F.

    1986-04-08

    A visually transmitting solar energy absorbing thermal storage module includes a thermal storage liquid containment chamber defined by an interior solar absorber panel, an exterior transparent panel having a heat mirror surface substantially covering the exterior surface thereof and associated top, bottom and side walls. Evaporation of the thermal storage liquid is controlled by a low vapor pressure liquid layer that floats on and seals the top surface of the liquid. Porous filter plugs are placed in filler holes of the module. An algicide and a chelating compound are added to the liquid to control biological and chemical activity while retaining visual clarity. A plurality of modules may be supported in stacked relation by a support frame to form a thermal storage wall structure.

  19. Regolith thermal energy storage for lunar nighttime power

    NASA Technical Reports Server (NTRS)

    Tillotson, Brian

    1992-01-01

    A scheme for providing nighttime electric power to a lunar base is described. This scheme stores thermal energy in a pile of regolith. Any such scheme must somehow improve on the poor thermal conductivity of lunar regolith in vacuum. Two previous schemes accomplish this by casting or melting the regolith. The scheme described here wraps the regolith in a gas-tight bag and introduces a light gas to enhance thermal conductivity. This allows the system to be assembled with less energy and equipment than schemes which require melting of regolith. A point design based on the new scheme is presented. Its mass from Earth compares favorably with the mass of a regenerative fuel cell of equal capacity.

  20. Effects of seasonal changes in dietary energy on body weight of captive Japanese macaques (Macaca fuscata).

    PubMed

    Aoki, Kouhei; Mitsutsuka, Syuuhei; Yamazaki, Ato; Nagai, Kazumi; Tezuka, Atsuko; Tsuji, Yamato

    2015-01-01

    Food availability varies seasonally for wild animals, and body weight fluctuates accordingly in the wild. In contrast, controlling availability of diet under captive condition is difficult from keepers' standpoint, and monotonous diet often causes health problems in captive animals. We evaluated the effects of a seasonally controlled diet on body weight of captive Japanese macaques (Macaca fuscata) in an outside enclosure at Ueno Zoo, Tokyo, Japan. We fed a high-energy diet in spring and fall, and a more restricted diet in summer and winter for 3 years (2011-2013). Seasonal changes in body weight were similar to those that occur in wild macaques: for both sexes, body weight was higher in spring and fall and lower in winter. A decrease in body weight between fall and winter occurred only in adults, which implied that reducing dietary intake in winter had a more severe effect on adults than on juveniles. Different from wild populations, the body weight of captive macaques did not decrease between spring and summer, which we attributed to a lack of movement within the enclosure and to excess energy intake in summer. In addition to controlling dietary composition, providing large enclosure with complex structure and making efforts of giving unpredictability in feeding are necessary to motivate the captive animals to be more active, which would cause the macaques to show seasonal change in body weight, which is found in wild.

  1. Dark energy in thermal equilibrium with the cosmological horizon?

    NASA Astrophysics Data System (ADS)

    Poitras, Vincent

    2014-03-01

    According to a generalization of black hole thermodynamics to a cosmological framework, it is possible to define a temperature for the cosmological horizon. The hypothesis of thermal equilibrium between the dark energy and the horizon has been considered by many authors. We find the restrictions imposed by this hypothesis on the energy transfer rate (Qi) between the cosmological fluids, assuming that the temperature of the horizon has the form T =b/2πR, where R is the radius of the horizon. We more specifically consider two types of dark energy: Chaplygin gas (CG) and dark energy with a constant equation of state parameter (wDE). In each case, we show that for a given radius R, there is a unique term Qde that is consistent with thermal equilibrium. We also consider the situation where, in addition to dark energy, other fluids (cold matter, radiation) are in thermal equilibrium with the horizon. We find that the interaction terms required for this will generally violate energy conservation (∑iQi=0).

  2. Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.

    ERIC Educational Resources Information Center

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

  3. Thermal energy storage. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Cavagnaro, D. M.

    1980-09-01

    The cited reports of federally-funded research concern thermal energy storage. The citations cover the design of equipment, performance evaluation, theory, materials used, and experimental design. This updated bibliography contains 240 citations, 128 of which are new entries to the previous edition.

  4. Fuels and chemicals from biomass using solar thermal energy

    NASA Technical Reports Server (NTRS)

    Giori, G.; Leitheiser, R.; Wayman, M.

    1981-01-01

    The significant nearer term opportunities for the application of solar thermal energy to the manufacture of fuels and chemicals from biomass are summarized, with some comments on resource availability, market potential and economics. Consideration is given to the production of furfural from agricultural residues, and the role of furfural and its derivatives as a replacement for petrochemicals in the plastics industry.

  5. Quantitative evaluation of ocean thermal energy conversion (OTEC): executive briefing

    SciTech Connect

    Gritton, E.C.; Pei, R.Y.; Hess, R.W.

    1980-08-01

    Documentation is provided of a briefing summarizing the results of an independent quantitative evaluation of Ocean Thermal Energy Conversion (OTEC) for central station applications. The study concentrated on a central station power plant located in the Gulf of Mexico and delivering power to the mainland United States. The evaluation of OTEC is based on three important issues: resource availability, technical feasibility, and cost.

  6. Fuels and chemicals from biomass using solar thermal energy

    NASA Astrophysics Data System (ADS)

    Giori, G.; Leitheiser, R.; Wayman, M.

    1981-05-01

    The significant nearer term opportunities for the application of solar thermal energy to the manufacture of fuels and chemicals from biomass are summarized, with some comments on resource availability, market potential and economics. Consideration is given to the production of furfural from agricultural residues, and the role of furfural and its derivatives as a replacement for petrochemicals in the plastics industry.

  7. Thermal energy storage subsystems. A collection of quarterly reports

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The design, development, and progress toward the delivery of three subsystems is discussed. The subsystem used a salt hydrate mixture for thermal energy storage. The program schedules, technical data, and other program activities from October 1, 1976, through December 31, 1977 are presented.

  8. A comparative analysis of human thermal conditions in outdoor urban spaces in the summer season in Singapore and Changsha, China.

    PubMed

    Yang, Wei; Wong, Nyuk Hien; Zhang, Guoqiang

    2013-11-01

    This paper presents the comparative analysis between the findings from two field surveys of human thermal conditions in outdoor urban spaces during the summer season. The first survey was carried out from August 2010 to May 2011 in Singapore and the second survey was carried out from June 2010 to August 2010 in Changsha, China. The physiologically equivalent temperature (PET) was utilized as the thermal index to assess the thermal conditions. Differences were found between the two city respondents in terms of thermal sensation, humidity sensation, and wind speed sensation. No big difference was found between the two city respondents regarding the sun sensation. The two city respondents had similar neutral PET of 28.1 °C for Singapore and 27.9 °C for Changsha, respectively. However, Singapore respondents were more sensitive to PET change than Changsha respondents and the acceptable PET range for Changsha respondents was wider than that for Singapore respondents. Besides, the two city respondents had different thermal expectations with the preferred PET of 25.2 °C and 22.1 °C for Singapore and Changsha, respectively. The results also reveal that Changsha respondents were more tolerant than Singapore respondents under hot conditions. Finally, two regression models were proposed for Singapore and Changsha to predict the human thermal sensation in a given outdoor thermal environment.

  9. Enhancing low-grade thermal energy recovery in a thermally regenerative ammonia battery using elevated temperatures.

    PubMed

    Zhang, Fang; LaBarge, Nicole; Yang, Wulin; Liu, Jia; Logan, Bruce E

    2015-03-01

    A thermally regenerative ammonia battery (TRAB) is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes. TRAB operation at 72 °C produced a power density of 236 ± 8 Wm(-2), with a linear decrease in power to 95 ± 5 Wm(-2) at 23 °C. The improved power at higher temperatures was due to reduced electrode overpotentials and more favorable thermodynamics for the anode reaction (copper oxidation). The energy density varied with temperature and discharge rates, with a maximum of 650 Wh m(-3) at a discharge energy efficiency of 54% and a temperature of 37 °C. The energy efficiency calculated with chemical process simulation software indicated a Carnot-based efficiency of up to 13% and an overall thermal energy recovery of 0.5%. It should be possible to substantially improve these energy recoveries through optimization of electrolyte concentrations and by using improved ion-selective membranes and energy recovery systems such as heat exchangers.

  10. Thermal energy storage - overview and specific insight into nitrate salts for sensible and latent heat storage.

    PubMed

    Pfleger, Nicole; Bauer, Thomas; Martin, Claudia; Eck, Markus; Wörner, Antje

    2015-01-01

    Thermal energy storage (TES) is capable to reduce the demand of conventional energy sources for two reasons: First, they prevent the mismatch between the energy supply and the power demand when generating electricity from renewable energy sources. Second, utilization of waste heat in industrial processes by thermal energy storage reduces the final energy consumption. This review focuses mainly on material aspects of alkali nitrate salts. They include thermal properties, thermal decomposition processes as well as a new method to develop optimized salt systems.

  11. Flexible hybrid energy cell for simultaneously harvesting thermal, mechanical, and solar energies.

    PubMed

    Yang, Ya; Zhang, Hulin; Zhu, Guang; Lee, Sangmin; Lin, Zong-Hong; Wang, Zhong Lin

    2013-01-22

    We report the first flexible hybrid energy cell that is capable of simultaneously or individually harvesting thermal, mechanical, and solar energies to power some electronic devices. For having both the pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based nanogenerator (NG) was used to harvest thermal and mechanical energies. Using aligned ZnO nanowire arrays grown on the flexible polyester (PET) substrate, a ZnO-poly(3-hexylthiophene) (P3HT) heterojunction solar cell was designed for harvesting solar energy. By integrating the NGs and the solar cells, a hybrid energy cell was fabricated to simultaneously harvest three different types of energies. With the use of a Li-ion battery as the energy storage, the harvested energy can drive four red light-emitting diodes (LEDs).

  12. High-temperature molten salt thermal energy storage systems

    NASA Technical Reports Server (NTRS)

    Petri, R. J.; Claar, T. D.; Tison, R. R.; Marianowski, L. G.

    1980-01-01

    The results of comparative screening studies of candidate molten carbonate salts as phase change materials (PCM) for advanced solar thermal energy storage applications at 540 to 870 C (1004 to 1600 F) and steam Rankine electric generation at 400 to 540 C (752 to 1004 F) are presented. Alkali carbonates are attractive as latent heat storage materials because of their relatively high storage capacity and thermal conductivity, low corrosivity, moderate cost, and safe and simple handling requirements. Salts were tested in 0.1 kWhr lab scale modules and evaluated on the basis of discharge heat flux, solidification temperature range, thermal cycling stability, and compatibility with containment materials. The feasibility of using a distributed network of high conductivity material to increase the heat flux through the layer of solidified salt was evaluated. The thermal performance of an 8 kWhr thermal energy storage (TES) module containing LiKCO3 remained very stable throughout 5650 hours and 130 charge/discharge cycles at 480 to 535 C (896 to 995 F). A TES utilization concept of an electrical generation peaking subsystem composed of a multistage condensing steam turbine and a TES subsystem with a separate power conversion loop was defined. Conceptual designs for a 100 MW sub e TES peaking system providing steam at 316 C, 427 C, and 454 C (600 F, 800 F, and 850 F) at 3.79 million Pa (550 psia) were developed and evaluated. Areas requiring further investigation have also been identified.

  13. Information-to-free-energy conversion: Utilizing thermal fluctuations

    PubMed Central

    Toyabe, Shoichi; Muneyuki, Eiro

    2013-01-01

    Maxwell’s demon is a hypothetical creature that can convert information to free energy. A debate that has lasted for more than 100 years has revealed that the demon’s operation does not contradict the laws of thermodynamics; hence, the demon can be realized physically. We briefly review the first experimental demonstration of Maxwell’s demon of Szilard’s engine type that converts information to free energy. We pump heat from an isothermal environment by using the information about the thermal fluctuations of a Brownian particle and increase the particle’s free energy. PMID:27493548

  14. Solar energy system performance evaluation-seasonal report for Elcam San Diego, San Diego, California

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The solar energy system, Elcam San Diego, was designed to supply domestic hot water heating for a single family residence located in Encinitas, California. System description, performance assessment, operating energy, energy savings, maintenance, and conclusions are presented. The system is a 'Sunspot' two tank cascade type, where solar energy is supplied to either a 66 gallon preheat tank (solar storage) or a 40 gallon domestic hot water tank. Water is pumped directly from one of the two tanks, through the 65 square feet collector array and back into the same tank. Freeze protection is provided by automatically circulating hot water from the hot water tank through the collectors and exposed plumbing when freezing conditions exist. Auxiliary energy is supplied by natural gas. Analysis is based on instrumented system data monitored and collected for one full season of operation.

  15. Solar energy system performance evaluation-seasonal report for Elcam San Diego, San Diego, California

    NASA Astrophysics Data System (ADS)

    1980-05-01

    The solar energy system, Elcam San Diego, was designed to supply domestic hot water heating for a single family residence located in Encinitas, California. System description, performance assessment, operating energy, energy savings, maintenance, and conclusions are presented. The system is a 'Sunspot' two tank cascade type, where solar energy is supplied to either a 66 gallon preheat tank (solar storage) or a 40 gallon domestic hot water tank. Water is pumped directly from one of the two tanks, through the 65 square feet collector array and back into the same tank. Freeze protection is provided by automatically circulating hot water from the hot water tank through the collectors and exposed plumbing when freezing conditions exist. Auxiliary energy is supplied by natural gas. Analysis is based on instrumented system data monitored and collected for one full season of operation.

  16. Experimental investigation of a packed bed thermal energy storage system

    NASA Astrophysics Data System (ADS)

    Cascetta, Mario; Cau, Giorgio; Puddu, Pierpaolo; Serra, Fabio

    2015-11-01

    In this work experimental investigations on a thermal energy storage system with a solid material as storage media and air as heat transfer fluid will be presented. The experimental test rig, installed at the DIMCM of the University of Cagliari, consists of a carbon steel tank filled with freely poured alumina beads that allows investigations of heat transfer phenomena in packed beds. The aim of this work is to show the influence of the operating conditions and physical parameters on thermocline formation and, in particular, the thermal behaviour of the thermal energy storage for repeated charging and discharging cycles. Better charging efficiency is obtained for lower values of mass flow rate and maximum air temperature and for increasing aspect ratio. A decreasing influence of the metal wall with continuous operation is also highlighted. In conclusion, the analysis focuses on the thermal hysteresis phenomenon, which causes degradation of the thermocline and the reduction of the energy that can be stored by the accumulator as the repeated number of cycles increases.

  17. Seasonal variation in energy balance and canopy conductance for a tropical savanna ecosystem of south-central Mato Grosso, Brazil

    NASA Astrophysics Data System (ADS)

    Rodrigues, T. R.; Vourlitis, G. L.; Lobo, F. D.; de Oliveira, R. G.; Nogueira, J. D.

    2013-12-01

    Tropical savanna (locally known as cerrado) comprises 24% of Brazil and is characterized by high temporal (climatic) and spatial (land cover) variation, biodiversity, and human activity. However, temporal variations in energy exchange are poorly understood, especially for mixed-grasslands (locally known as campo-sujo), making current and future patterns of energy balance highly uncertain. We used eddy covariance to measure latent (Le) and sensible (H) heat flux of a mixed-grassland, and linked meteorological and remote-sensing data to determine the controls on these fluxes. We hypothesized that (1) seasonal variations in H and Le would be large due to variations in precipitation, (2) ecosystem phenology, estimated using the Enhanced Vegetation Index (EVI), would be the best predictor of seasonal variation in Le, and (3) cerrado, transitional, and humid evergreen forests would have similar rates of average annual Le despite large seasonal variation in cerrado Le. We found that campo-sujo exhibits large seasonal fluctuations in energy balance that are driven by rainfall, and that responses to rainfall pulses are rapid and dynamic, especially during the dry season. Seasonal variations in the EVI did not affect energy fluxes; however, when energy fluxes were normalized with net radiation (Rn), the EVI was found to significantly affect the amount of available energy dissipated by H, Le, and G, indicating an important ground surface feedback on energy partitioning. Compared to other tropical ecosystems, cerrado exhibited substantially more seasonal variation in energy flux density than forested tropical ecosystems. For example, cerrado had lower rates of Le during the dry season, due to water limitations, but higher rates of wet-season Le than tropical forests, which were likely limited by radiation due to frequent cloud cover. Overall, these seasonal variations caused average annual rates of Le to be similar between cerrado, transitional, and humid evergreen forests.

  18. Nanoparticles for heat transfer and thermal energy storage

    DOEpatents

    Singh, Dileep; Cingarapu, Sreeram; Timofeeva, Elena V.; Moravek, Michael

    2015-07-14

    An article of manufacture and method of preparation thereof. The article of manufacture and method of making the article includes an eutectic salt solution suspensions and a plurality of nanocrystalline phase change material particles having a coating disposed thereon and the particles capable of undergoing the phase change which provides increase in thermal energy storage. In addition, other articles of manufacture can include a nanofluid additive comprised of nanometer-sized particles consisting of copper decorated graphene particles that provide advanced thermal conductivity to heat transfer fluids.

  19. Dimensional Analysis of Ocean Thermal Energy Conversion Heat Exchangers

    DTIC Science & Technology

    1977-06-30

    8217thIJt4IiTY CLASSIFICATION OF TWI4S PAG(E ona Dola t ern.r) 20. (continued) c-a• of factors having significance in OTEC (Ocean Thermal Energy Conversion...heat exchangers. Certain of these groups are then evaluated for a model and prototype OTEC -Type heat exchanger using the same working fluid and ex...Development Administration, and the U. S. Navy are brought out. Chapter II investigates the scaling problems of heat ex- changers in OTEC (Ocean Thermal

  20. Composite salt/ceramic media for thermal energy storage applications

    NASA Astrophysics Data System (ADS)

    Claar, T. D.; Petri, R. J.; Ong, E. T.

    An advanced thermal energy storage (TES) media concept based on composite carbonate salt/ceramic materials is being developed for high-temperature applications such as industrial waste heat recovery and storage and solar thermal power systems. This composite latent/sensible media concept permits direct-contact heat exchange between the storage media and compatible working fluids, thus offering significant potential TES system performance and cost advantages over previous molten-salt latent-heat storage systems. Composite media development activities, materials stability test results, and planned TES performance evaluation tests are discussed.

  1. Simulation and evaluation of latent heat thermal energy storage

    NASA Technical Reports Server (NTRS)

    Sigmon, T. W.

    1980-01-01

    The relative value of thermal energy storage (TES) for heat pump storage (heating and cooling) as a function of storage temperature, mode of storage (hotside or coldside), geographic locations, and utility time of use rate structures were derived. Computer models used to simulate the performance of a number of TES/heat pump configurations are described. The models are based on existing performance data of heat pump components, available building thermal load computational procedures, and generalized TES subsystem design. Life cycle costs computed for each site, configuration, and rate structure are discussed.

  2. 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

  3. Systems analysis techniques for annual cycle thermal energy storage solar systems

    SciTech Connect

    Baylin, F.; Sillman, S.

    1980-07-01

    Community-scale annual cycle thermal energy storage (ACTES) solar systems are promising options for building heat and cooling. A variety of approaches are feasible in modeling ACTES solar systems. The key parameter in such efforts, average collector efficiency, is first examined, followed by several approaches for simple and effective modeling. Methods are also examined for modeling building loads for structures based on both conventional and passive architectural designs. Two simulation models for sizing solar heating systems with annual storage are presented next. Validation is presented by comparison with the results of a study of seasonal storage systems based on SOLANSIM, an hour-by-hour simulation. These models are presently being used to examine the economic trade-off between collector field area and storage capacity. Finally, programs in the US Department of Energy directed toward developing either other system components such as improved tanks and solar ponds or design tools for ACTES solar systems are examined.

  4. Guidelines for conceptual design and evaluation of aquifer thermal energy storage

    NASA Astrophysics Data System (ADS)

    Meyer, C. F.; Hauz, W.

    1980-10-01

    Guidelines are presented for use as a tool by those considering application of aquifer thermal energy storage (ATES) technology. The guidelines assist utilities, municipalities, industries, and other entities in the conceptual design and evaluation of systems employing ATES. The potential benefits of ATES are described, an overview is presented of the technology and its applications, and rules of thumb are provided for quickly judging whether a proposed project has sufficient promise to warrant detailed conceptual design and evaluation. The characteristics of sources and end uses of heat and chill which are seasonally mismatched and may benefit from ATES are discussed. Storage and transport subsystems and their expected performance and cost are described. A methodology is presented for conceptual design of an ATES system and evaluation of its technical and economic feasibility in terms of energy conservation, cost savings, fuel substitution, improved dependability of supply, and abatement of pollution.

  5. Advanced Coupled Simulation of Borehole Thermal Energy Storage Systems and Above Ground Installations

    NASA Astrophysics Data System (ADS)

    Welsch, Bastian; Rühaak, Wolfram; Schulte, Daniel O.; Bär, Kristian; Sass, Ingo

    2016-04-01

    Seasonal thermal energy storage in borehole heat exchanger arrays is a promising technology to reduce primary energy consumption and carbon dioxide emissions. These systems usually consist of several subsystems like the heat source (e.g. solarthermics or a combined heat and power plant), the heat consumer (e.g. a heating system), diurnal storages (i.e. water tanks), the borehole thermal energy storage, additional heat sources for peak load coverage (e.g. a heat pump or a gas boiler) and the distribution network. For the design of an integrated system, numerical simulations of all subsystems are imperative. A separate simulation of the borehole energy storage is well-established but represents a simplification. In reality, the subsystems interact with each other. The fluid temperatures of the heat generation system, the heating system and the underground storage are interdependent and affect the performance of each subsystem. To take into account these interdependencies, we coupled a software for the simulation of the above ground facilities with a finite element software for the modeling of the heat flow in the subsurface and the borehole heat exchangers. This allows for a more realistic view on the entire system. Consequently, a finer adjustment of the system components and a more precise prognosis of the system's performance can be ensured.

  6. Predicting Formation Damage in Aquifer Thermal Energy Storage Systems Utilizing a Coupled Hydraulic-Thermal-Chemical Reservoir Model

    NASA Astrophysics Data System (ADS)

    Müller, Daniel; Regenspurg, Simona; Milsch, Harald; Blöcher, Guido; Kranz, Stefan; Saadat, Ali

    2014-05-01

    In aquifer thermal energy storage (ATES) systems, large amounts of energy can be stored by injecting hot water into deep or intermediate aquifers. In a seasonal production-injection cycle, water is circulated through a system comprising the porous aquifer, a production well, a heat exchanger and an injection well. This process involves large temperature and pressure differences, which shift chemical equilibria and introduce or amplify mechanical processes. Rock-fluid interaction such as dissolution and precipitation or migration and deposition of fine particles will affect the hydraulic properties of the porous medium and may lead to irreversible formation damage. In consequence, these processes determine the long-term performance of the ATES system and need to be predicted to ensure the reliability of the system. However, high temperature and pressure gradients and dynamic feedback cycles pose challenges on predicting the influence of the relevant processes. Within this study, a reservoir model comprising a coupled hydraulic-thermal-chemical simulation was developed based on an ATES demonstration project located in the city of Berlin, Germany. The structural model was created with Petrel, based on data available from seismic cross-sections and wellbores. The reservoir simulation was realized by combining the capabilities of multiple simulation tools. For the reactive transport model, COMSOL Multiphysics (hydraulic-thermal) and PHREEQC (chemical) were combined using the novel interface COMSOL_PHREEQC, developed by Wissmeier & Barry (2011). It provides a MATLAB-based coupling interface between both programs. Compared to using COMSOL's built-in reactive transport simulator, PHREEQC additionally calculates adsorption and reaction kinetics and allows the selection of different activity coefficient models in the database. The presented simulation tool will be able to predict the most important aspects of hydraulic, thermal and chemical transport processes relevant to

  7. Molten Glass for Thermal Storage: Advanced Molten Glass for Heat Transfer and Thermal Energy Storage

    SciTech Connect

    2012-01-01

    HEATS Project: Halotechnics is developing a high-temperature thermal energy storage system using a new thermal-storage and heat-transfer material: earth-abundant and low-melting-point molten glass. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Halotechnics new thermal storage material targets a price that is potentially cheaper than the molten salt used in most commercial solar thermal storage systems today. It is also extremely stable at temperatures up to 1200°C—hundreds of degrees hotter than the highest temperature molten salt can handle. Being able to function at high temperatures will significantly increase the efficiency of turning heat into electricity. Halotechnics is developing a scalable system to pump, heat, store, and discharge the molten glass. The company is leveraging technology used in the modern glass industry, which has decades of experience handling molten glass.

  8. Review of pyroelectric thermal energy harvesting and new MEMs based resonant energy conversion techniques

    SciTech Connect

    Hunter, Scott Robert; Lavrik, Nickolay V; Mostafa, Salwa; Rajic, Slobodan; Datskos, Panos G

    2012-01-01

    Harvesting electrical energy from thermal energy sources using pyroelectric conversion techniques has been under investigation for over 50 years, but it has not received the attention that thermoelectric energy harvesting techniques have during this time period. This lack of interest stems from early studies which found that the energy conversion efficiencies achievable using pyroelectric materials were several times less than those potentially achievable with thermoelectrics. More recent modeling and experimental studies have shown that pyroelectric techniques can be cost competitive with thermoelectrics and, using new temperature cycling techniques, has the potential to be several times as efficient as thermoelectrics under comparable operating conditions. This paper will review the recent history in this field and describe the techniques that are being developed to increase the opportunities for pyroelectric energy harvesting. The development of a new thermal energy harvester concept, based on temperature cycled pyroelectric thermal-to-electrical energy conversion, are also outlined. The approach uses a resonantly driven, pyroelectric capacitive bimorph cantilever structure that can be used to rapidly cycle the temperature in the energy harvester. The device has been modeled using a finite element multi-physics based method, where the effect of the structure material properties and system parameters on the frequency and magnitude of temperature cycling, and the efficiency of energy recycling using the proposed structure, have been modeled. Results show that thermal contact conductance and heat source temperature differences play key roles in dominating the cantilever resonant frequency and efficiency of the energy conversion technique. This paper outlines the modeling, fabrication and testing of cantilever and pyroelectric structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal

  9. Performance issues in solar thermal energy transport systems

    NASA Astrophysics Data System (ADS)

    Zimmerman, P. W.

    1986-07-01

    Pacific Northwest Laboratory, sponsored by the US Department of Energy through Sandia National Laboratories, is performing an assessment of three solar thermal electricity generating concepts; central receivers, dishes, and troughs. Concepts are being studied over a range of system sizes 0.5 MWe to 100 MWe with solar multiples from 1.0 to 2.8. Central receiver systems using molten salt, sodium, and water-steam working fluids are studied. The dish system selected for study uses a kinematic Stirling engine at the focal point, and the trough system is based on Accurex designed collectors heating a heat transfer oil. Of the three concepts studied, the central receiver and trough systems utilize thermal transport systems. A thermal transport system is the piping and fluid required to transfer thermal energy between receiver, and storage and between storage and steam generator. The literature contains many transport system designs, most of which are optimized with regard to cost and performance. We used the parameters specified from the optimizations to design our systems and scale the designs over the 0.5 MWe to 100 MWe size range. From these designs, thermal losses and pump sizes are derived then combined in a system model to obtain total annual averaged efficiency as a function of plant field size. We found that central receiver transport efficiency improves with field size whereas trough transport efficiency degrades with field size. We found that overnight cooldown accounts for roughly 50% of the total thermal losses for all transport systems. Trough performance is substantially degraded because the receiver tubes are not drained which allows a large overnight heat loss. Trough transport performance was found to be sensitive to fluid velocity.

  10. High Energy Density Thermal Batteries: Thermoelectric Reactors for Efficient Automotive Thermal Storage

    SciTech Connect

    2011-11-15

    HEATS Project: Sheetak is developing a new HVAC system to store the energy required for heating and cooling in EVs. This system will replace the traditional refrigerant-based vapor compressors and inefficient heaters used in today’s EVs with efficient, light, and rechargeable hot-and-cold thermal batteries. The high energy density thermal battery—which does not use any hazardous substances—can be recharged by an integrated solid-state thermoelectric energy converter while the vehicle is parked and its electrical battery is being charged. Sheetak’s converters can also run on the electric battery if needed and provide the required cooling and heating to the passengers—eliminating the space constraint and reducing the weight of EVs that use more traditional compressors and heaters.

  11. Impact of climatic factors on energy consumption during the heating season

    NASA Astrophysics Data System (ADS)

    Ginzburg, A. S.; Reshetar, O. A.; Belova, I. N.

    2016-09-01

    Global and regional climate changes produce a significant effect on energy production and consumption, especially on heating and air conditioning in residential, industrial, commercial, and office rooms. In Russia, with its contracting climate conditions, energy consumption varies a lot in different regions. Thus, we have to review the dynamics of energy consumption during the cold season individually for each region of the country. We analyzed the dynamics of duration and temperature of the heating season in Moscow region and completed a comparative study of heat energy consumption, actual and calculated based on the 'degreedays' concept, in the municipal economy of Moscow during the last decade. Based on the actual data analysis, we proved that conservation of energy resources in a large city relies not so much on a shortening of the heating period as on the growth of atmospheric air temperature in winter. The projected climate warming in the Moscow region in the nearest decades, along with measures of energy conservation, will promote a significant reduction in energy consumption of the municipal economy in winter. The results shown in this article were obtained in the process of preparing and implementing project no. 16-17-00114 by the Russian Science Foundation "Analysis of an impact of the regional climate change on the residential and commercial energy consumption of Russian megacities," within the main area of focus of the Russian Science Foundation, which is "Fundamental Research and Exploration in Main Topical Areas of Focus." The project was implemented within the framework of the scientific area of focus, which is "Reduction of the Risk and Mitigation of Consequences of Natural and Man-made Disasters" ("Studying Economical, Political, and Social Consequences of Global Climate Changes" problem).

  12. High temperature thermal energy storage in steel and sand

    NASA Technical Reports Server (NTRS)

    Turner, R. H.

    1979-01-01

    The technical and economic potential for high temperature (343 C, 650 F) thermal energy storage in hollow steel ingots, pipes embedded in concrete, and for pipes buried in sand was evaluated. Because it was determined that concrete would separate from pipes due to thermal stresses, concrete was replaced by sand, which is free from thermal stresses. Variations of the steel ingot concept were not cost effective compared to the sand-pipe approach, therefore, the sand-pipe thermal storage unit (TSU) was evaluated in depth to assess the approximate tube spacing requirements consistent with different system performance characteristics and also attendant system costs. For large TSUs which do not require fast response times, the sand-pipe approach offers attractive possibilities. A pipe diameter about 9 cm (3.5 in) and pipe spacing of approximately 25 cm (10 in), with sand filling the interspaces, appears appropriate. Such a TSU system designed for 8 hours charge/discharge cycle has an energy unit storage cost (CE) of $2.63/kWhr-t and a power unit storage cost (Cp) of $42/kW-t (in 1977 dollars).

  13. Sensitivity Analysis on the Performance of Medium Deep Borehole Thermal Energy Storage Systems

    NASA Astrophysics Data System (ADS)

    Welsch, Bastian; Rühaak, Wolfram; Schulte, Daniel O.; Bär, Kristian; Sass, Ingo

    2016-04-01

    Seasonal thermal energy storages using arrays of medium deep (400 m - 1500 m) borehole heat exchangers (BHE) have two main advantages over near surface (< 400 m) BHE storages. Medium deep borehole thermal energy storages (MD-BTES) have a lower thermal impact on shallow groundwater resources and require less surface area. However, the storage performance indicators like the efficiency, the storage capacity and the supplied fluid temperature of MD-BTES are unknown as such system has not been put into practice so far. To study the influence of various design and operation parameters on the storage performance, more than 240 numerical models of different MD-BTES systems were compared in a sensitivity analysis. Most importantly, the BHE length, the number of BHEs, the spacing between the BHEs, the inlet temperatures of the heat transfer fluid into the BHEs and the underground properties were varied. A simplified underground model was used and also a simplified operation procedure was applied for a period of 30 years of storage operation. The results show a strong dependency of the storage performance on the studied design and operation parameters as well as on the underground properties. In the best case, storage efficiency reaches over 80 % in the 30th year of operation, whereas poorly designed storage systems show efficiencies of less than 20 %.

  14. The influence of thermal inertia on Mars' seasonal pressure variation and the effect of the weather component

    NASA Technical Reports Server (NTRS)

    Wood, S. E.; Paige, D. A.

    1993-01-01

    Using a Leighton-Murray type diurnal and seasonal Mars thermal model, we found that it is possible to reproduce the seasonal variation in daily-averaged pressures (approximately 680-890 Pa) measured by Viking Lander 1 (VL1), during years without global dust storms, with a standard deviation of less than 5 Pa. In this simple model, surface CO2, frost condensation, and sublimation rates at each latitude are determined by the net effects of radiation, latent heat, and heat conduction in subsurface soil layers. An inherent assumption of our model is that the seasonal pressure variation is due entirely to the exchange of mass between the atmosphere and polar caps. However, the results of recent Mars GCM modeling have made it clear that there is a significant dynamical contribution to the seasonal pressure variation. This 'weather' component is primarily due to large-scale changes in atmospheric circulation, and its magnitude depends somewhat on the dust content of the atmosphere. The overall form of the theoretical weather component at the location of VL1, as calculated by the AMES GCM, remains the same over the typical range of Mars dust opacities.

  15. An assessment methodology for thermal energy storage evaluation

    NASA Astrophysics Data System (ADS)

    Brown, D. R.; Dirks, J. A.; Drost, M. K.; Spanner, G. E.; Williams, T. A.

    1987-11-01

    This report documents an assessment methodology for evaluating the cost, performance, and overall economic feasibility of thermal energy storage (TES) concepts. The methodology was developed by Thermal Energy Storage Evaluation Program personnel at Pacific Northwest Laboratory (PNL) for use by PNL and other TES concept evaluators. The methodology is generically applicable to all TES concepts; however, specific analyses may require additional or more detailed definition of the ground rules, assumptions, and analytical approach. The overall objective of the assessment methodology is to assist in preparing equitable and proper evaluations of TES concepts that will allow developers and end-users to make valid decisions about research and development (R and D) and implementation. The methodology meets this objective by establishing standard approaches, ground rules, assumptions, and definitions that are analytically correct and can be consistently applied by concept evaluators.

  16. Designing energy dissipation properties via thermal spray coatings

    SciTech Connect

    Brake, Matthew R. W.; Hall, Aaron Christopher; Madison, Jonathan D.

    2016-12-14

    The coefficient of restitution is a measure of energy dissipation in a system across impact events. Often, the dissipative qualities of a pair of impacting components are neglected during the design phase. This research looks at the effect of applying a thin layer of metallic coating, using thermal spray technologies, to significantly alter the dissipative properties of a system. We studied the dissipative properties across multiple impacts in order to assess the effects of work hardening, the change in microstructure, and the change in surface topography. The results of the experiments indicate that any work hardening-like effects are likely attributable to the crushing of asperities, and the permanent changes in the dissipative properties of the system, as measured by the coefficient of restitution, are attributable to the microstructure formed by the thermal spray coating. Furthermore, the microstructure appears to be robust across impact events of moderate energy levels, exhibiting negligible changes across multiple impact events.

  17. An assessment methodology for thermal energy storage evaluation

    SciTech Connect

    Brown, D.R.; Dirks, J.A.; Drost, M.K.; Spanner, G.E.; Williams, T.A.

    1987-11-01

    This report documents an assessment methodology for evaluating the cost, performance, and overall economic feasibility of thermal energy storage (TES) concepts. The methodology was developed by Thermal Energy Storage Evaluation Program personnel at Pacific Northwest Laboratory (PNL) for use by PNL and other TES concept evaluators. The methodology is generically applicable to all TES concepts; however, specific analyses may require additional or more detailed definition of the ground rules, assumptions, and analytical approach. The overall objective of the assessment methodology is to assist in preparing equitable and proper evaluations of TES concepts that will allow developers and end-users to make valid decisions about research and development (R and D) and implementation. The methodology meets this objective by establishing standard approaches, ground rules, assumptions, and definitions that are analytically correct and can be consistently applied by concept evaluators. 15 refs., 4 figs., 13 tabs.

  18. Modelling the Variability of the Wind Energy Resource on Monthly and Seasonal Timescales

    NASA Astrophysics Data System (ADS)

    Alonzo, Bastien; Ringkjøb, Hans-Kristian; Jourdier, Benedicte; Drobinski, Philippe; Plougonven, Riwal; Tankov, Peter

    2016-04-01

    We study the variability of the wind energy resource in France on monthly to seasonal timescales. On such long-term timescales, the variability of the surface wind speed is strongly influenced by the large-scale situation of the atmosphere. As an example variations in the position of the storm track west of France directly impact surface wind in the North of France in autumn and winter. We investigate the relationship between the large scale circulation and the surface wind speed, summarizing the former by a principal component analysis, so that the large-scale mass distribution is described by a small set of coefficients. We then apply a multi polynomial relationship to model the monthly and seasonal distribution of surface wind speeds given the knowledge of these few coefficients. Different methods for this reconstruction are assessed. While the first attempts to reconstruct the wind with a daily resolution, the three others directly aim at reconstructing the distribution of the wind, assuming it is well described as a Weibull distribution : One is based on the reconstruction of 3 moments of this theoretical distribution, another is based on the reconstruction of two percentiles, and the last one is based on the direct reconstruction of the shape and scale parameter of the Weibull distribution. The last two methods show good performance and better skills to reproduce the monthly and seasonal distribution of the wind speed with respect to the climatology. We then apply those methods to seasonal forecasts from the European Center for Medium-range Weather Forecasts (ECMWF) in an attempt of forecasting the monthly and seasonal distribution of the surface wind speed. For one month time-horizon, the forecasting performance is superior to climatology.

  19. Thermal modeling with solid/liquid phase change of the thermal energy storage experiment

    NASA Technical Reports Server (NTRS)

    Skarda, J. Raymond Lee

    1991-01-01

    A thermal model which simulates combined conduction and phase change characteristics of thermal energy storage (TES) materials is presented. Both the model and results are presented for the purpose of benchmarking the conduction and phase change capabilities of recently developed and unvalidated microgravity TES computer programs. Specifically, operation of TES-1 is simulated. A two-dimensional SINDA85 model of the TES experiment in cylindrical coordinates was constructed. The phase change model accounts for latent heat stored in, or released from, a node undergoing melting and freezing.

  20. Thermal Energy in Carbon Nanotube and Graphene Composite Materials

    NASA Astrophysics Data System (ADS)

    Schiffres, Scott N.

    Low-dimensional materials, like carbon nanotubes (CNTs) and graphene, possess extraordinary properties---higher thermal conductivity than any bulk material, mechanical strength 10-100 times greater than steel on a mass basis, and electrical current capacity 1000 times greater than copper. While composites incorporating these low-dimensional materials promise solutions to global sustainability challenges, significant transport barriers exist at the matrix interface that influence the composite properties. My PhD research sought to address this knowledge gap. I've experimentally explored how CNTs and graphene impact thermal conductivity when added in small volume fractions to gases, liquids and solids through the study of CNT aerogels (ultra lightweight, 8 kg/m3, 99.6% void space), and phase change nanocomposites (hexadecane-graphene). I measured the thermal conductivity of the CNT aerogel with various filling gases versus pressure using a novel technique that targeted ultralow thermal conductivity materials, called metal-coated 3o. I observed amplified energy transport length scales resulting from low gas accommodation, which is a general feature of carbon based nanoporous materials. Our evidence also shows that despite the high thermal conductivity of CNTs, thermal conduction through the CNT network is limited by the high thermal boundary resistance at van der Waals bonded CNT junctions. In the second system, I studied thermal and electrical conductivity of hexadecane- multi-layered-graphene (MLG) phase change nanocomposites to understand how morphology of the MLG network impacts transport. By adjusting the freezing rate, the electrical conductivity in the solid phase can be tuned between 1 and 5 orders-of-magnitude and the solid-liquid thermal conductivity ratio can be varied between 2.6 to 3.0. This research has yielded interesting insights into the tunability of nanocomposites and the physics underlying it, including evidence to indicate that the presence of

  1. Data Analysis for Ocean Thermal Energy Conversion (otec)

    DTIC Science & Technology

    1979-11-01

    Unit Number 01. The author wishes to thank Mr. David Boswell of DTNSRDC, Annapolis, Maryland for his work on OTEC software development. The...assistance of Mr. Glenn Grannemann of Carnegie-Mellon University, Pittsburgh, Pennsylvania, in reviewing Panama City OTEC data analysis techniques is...FOR OCEAN THERMAL ENERGY Technical Memodnndum CONVERSION ( OTEC ) , * IERFORMING Ono, XCIPOOT mulesea 7. AUTNORf.) .. CONTRACT OR GRANT S411jbdb .ftf

  2. Dish concentrators for solar thermal energy: Status and technology development

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.

    1982-01-01

    Point-focusing concentrators under consideration for solar thermal energy use are reviewed. These concentrators differ in such characteristics as optical configuration, optical materials, structure for support of the optical elements and of the receiver, mount, foundation, drive, controls and enclosure. Concentrator performance and cost are considered. Technology development is outlined, including wind loads and aerodynamics; precipitation, sand, and seismic considerations; and maintenance and cleaning.

  3. Kinship and seasonal migration among the Aymara of southern Peru: human adaptation to energy scarcity

    SciTech Connect

    Collins, J.L.

    1981-01-01

    The people of the southern Peruvian highlands have adapted to a condition of energy scarcity through seasonal migration to lowland areas. In the disrict of Sarata (a fictitious name for a real district on the northeastern shore of Lake Titicaca) people spend three to seven months of every year growing coffee in the Tambopata Valley of the eastern Andes. This migratory pattern, which is hundreds of years old, provides the context for an investigation of human adaptive processes. This study presents models of the flow of energy through high-altitude households and shows that energy is a limiting factor for the population. There are two periods when energy subsidies from lowland regions become crucial to the continued survival of highland households. These are the periods of peak growth and reproduction experienced by households early in their developmental cycles, and times of sharply lowered productivity caused by environmental crises such as drought or killing frosts. Seasonal migration provides the subsidies that households rely on during these periods.

  4. Effect of thermal environment on the temporal, spatial and seasonal occurrence of measles in Ondo state, Nigeria

    NASA Astrophysics Data System (ADS)

    Omonijo, Akinyemi Gabriel; Matzarakis, Andreas; Oguntoke, Olusegun; Adeofun, Clement Olabinjo

    2012-09-01

    We investigated the temporal and spatial dynamics, as well as the seasonal occurrence of measles in Ondo state, Nigeria, to better understand the role of the thermal environment in the occurrence of the childhood killer disease measles, which ranks among the top ten leading causes of child deaths worldwide. The linkages between measles and atmospheric environmental factors were examined by correlating human-biometeorological parameters in the study area with reported clinical cases of measles for the period 1998-2008. We also applied stepwise regression analysis in order to determine the human-biometeorological parameters that lead to statistical changes in reported clinical cases of measles. We found that high reported cases of measles are associated with the least populated areas, where rearing and cohabitation of livestock/domestic animals within human communities are common. There was a significant correlation ( P < 0.01) between monthly cases of measles and human-biometeorological parameters except wind speed and vapour pressure. High transmission of measles occurred in the months of January to May during the dry season when human thermal comfort indices are very high. This highlights the importance of the thermal environment in disease demographics since it accounted for more than 40% variation in measles transmission within the study period.

  5. Estimating evaporation with thermal UAV data and two-source energy balance models

    NASA Astrophysics Data System (ADS)

    Hoffmann, H.; Nieto, H.; Jensen, R.; Guzinski, R.; Zarco-Tejada, P.; Friborg, T.

    2016-02-01

    Estimating evaporation is important when managing water resources and cultivating crops. Evaporation can be estimated using land surface heat flux models and remotely sensed land surface temperatures (LST), which have recently become obtainable in very high resolution using lightweight thermal cameras and Unmanned Aerial Vehicles (UAVs). In this study a thermal camera was mounted on a UAV and applied into the field of heat fluxes and hydrology by concatenating thermal images into mosaics of LST and using these as input for the two-source energy balance (TSEB) modelling scheme. Thermal images are obtained with a fixed-wing UAV overflying a barley field in western Denmark during the growing season of 2014 and a spatial resolution of 0.20 m is obtained in final LST mosaics. Two models are used: the original TSEB model (TSEB-PT) and a dual-temperature-difference (DTD) model. In contrast to the TSEB-PT model, the DTD model accounts for the bias that is likely present in remotely sensed LST. TSEB-PT and DTD have already been well tested, however only during sunny weather conditions and with satellite images serving as thermal input. The aim of this study is to assess whether a lightweight thermal camera mounted on a UAV is able to provide data of sufficient quality to constitute as model input and thus attain accurate and high spatial and temporal resolution surface energy heat fluxes, with special focus on latent heat flux (evaporation). Furthermore, this study evaluates the performance of the TSEB scheme during cloudy and overcast weather conditions, which is feasible due to the low data retrieval altitude (due to low UAV flying altitude) compared to satellite thermal data that are only available during clear-sky conditions. TSEB-PT and DTD fluxes are compared and validated against eddy covariance measurements and the comparison shows that both TSEB-PT and DTD simulations are in good agreement with eddy covariance measurements, with DTD obtaining the best results. The

  6. Experimental measurements of thermal properties of high-temperature refractory materials used for thermal energy storage

    NASA Astrophysics Data System (ADS)

    El-Leathy, Abdelrahman; Jeter, Sheldon; Al-Ansary, Hany; Abdel-Khalik, Said; Golob, Matthew; Danish, Syed Noman; Saeed, Rageh; Djajadiwinata, Eldwin; Al-Suhaibani, Zeyad

    2016-05-01

    This paper builds on studies conducted on thermal energy storage (TES) systems that were built as a part of the work performed for a DOE-funded SunShot project titled "High Temperature Falling Particle Receiver". In previous studies, two small-scale TES systems were constructed for measuring heat loss at high temperatures that are compatible with the falling particle receiver concept, both of which had shown very limited heat loss. Through the course of those studies, it became evident that there was a lack of information about the thermal performance of some of the insulating refractory materials used in the experiments at high temperatures, especially insulating firebrick and perlite concrete. This work focuses on determining the thermal conductivities of those materials at high temperatures. The apparatus consists of a prototype cylindrical TES bin built with the same wall construction used in previous studies. An electric heater is placed along the centerline of the bin, and thermocouples are used to measure temperature at the interfaces between all layers. Heat loss is measured across one of the layers whose thermal conductivity had already been well established using laboratory experiments. This value is used to deduce the thermal conductivity of other layers. Three interior temperature levels were considered; namely, 300°C, 500°C, and 700°C. Results show that the thermal conductivity of insulating firebrick remains low (approximately 0.22 W/m.K) at an average layer temperature as high as 640°C, but it was evident that the addition of mortar had an impact on its effective thermal conductivity. Results also show that the thermal conductivity of perlite concrete is very low, approximately 0.15 W/m.K at an average layer temperature of 360°C. This is evident by the large temperature drop that occurs across the perlite concrete layer. These results should be useful for future studies, especially those that focus on numerical modeling of TES bins.

  7. The effects of season and sand mining activities on thermal regime and water quality in a large shallow tropical lake.

    PubMed

    Sharip, Zati; Zaki, Ahmad Taqiyuddin Ahmad

    2014-08-01

    Thermal structure and water quality in a large and shallow lake in Malaysia were studied between January 2012 and June 2013 in order to understand variations in relation to water level fluctuations and in-stream mining activities. Environmental variables, namely temperature, turbidity, dissolved oxygen, pH, electrical conductivity, chlorophyll-A and transparency, were measured using a multi-parameter probe and a Secchi disk. Measurements of environmental variables were performed at 0.1 m intervals from the surface to the bottom of the lake during the dry and wet seasons. High water level and strong solar radiation increased temperature stratification. River discharges during the wet season, and unsustainable sand mining activities led to an increased turbidity exceeding 100 NTU, and reduced transparency, which changed the temperature variation and subsequently altered the water quality pattern.

  8. Effect of effluents of a thermal power plant complex on reproductive processs of a winter season weed

    SciTech Connect

    Khan, F.A.; Iqbal, M.; Ghouse, A.K.M. )

    1990-05-01

    The Kasimpur Thermal Power Plant Complex (located in the District Aligarh, Uttar Pradesh, India) runs on a low grade, sulphur rich, bituminous type of coal with a daily average consumption rte of about 3,192 metric tons during winter season. Its effluents, mainly consisting of oxides of sulphur, nitrogen and carbon as well as particulate matters, were noted to affect the reproductive behavior of Melilotus indica-a winter season weed growing wild as a component of a grassland community. The samples consisting of 10 plants were collected at monthly intervals from 5 sites located about 0.5, 2, 6, 12 and 20 km leaward from the Complex. Emergence of inflorescence was delayed at the polluted sites. However, fruit formation started simultaneously (in March) at all the five sites. The pollution induced senescence of floral buds, flowers and fruits, but did not alter markedly weight of seed and fruit.

  9. Thermal energy storage for industrial waste heat recovery

    NASA Technical Reports Server (NTRS)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    The potential is examined for waste heat recovery and reuse through thermal energy storage in five specific industrial categories: (1) primary aluminum, (2) cement, (3) food processing, (4) paper and pulp, and (5) iron and steel. Preliminary results from Phase 1 feasibility studies suggest energy savings through fossil fuel displacement approaching 0.1 quad/yr in the 1985 period. Early implementation of recovery technologies with minimal development appears likely in the food processing and paper and pulp industries; development of the other three categories, though equally desirable, will probably require a greater investment in time and dollars.

  10. Energy storage and thermal control system design status

    NASA Technical Reports Server (NTRS)

    Simons, Stephen N.; Willhoite, Bryan C.; Vanommering, Gert

    1989-01-01

    The Space Station Freedom electric power system (EPS) will initially rely on photovoltaics for power generation and Ni/H2 batteries for electrical energy storage. The current design for and the development status of two major subsystems in the PV Power Module is discussed. The energy storage subsystem comprised of high capacity Ni/H2 batteries and the single-phase thermal control system that rejects the excess heat generated by the batteries and other components associated with power generation and storage is described.

  11. United States Department of Energy Thermally Activated Heat Pump Program

    SciTech Connect

    Fiskum, R.J.; Adcock, P.W.; DeVault, R.C.

    1996-06-01

    The US Department of Energy (DOE) is working with partners from the gas heating and cooling industry to improve energy efficiency using advance absorption technologies, to eliminate chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), to reduce global warming through more efficient combustion of natural gas, and to impact electric peak demand of air conditioning. To assist industry in developing these gas heating and cooling absorption technologies, the US DOE sponsors the Thermally Activated Heat Pump Program. It is divided into five key activities, addressing residential gas absorption heat pumps, large commercial chillers, advanced absorption fluids, computer-aided design, and advanced ``Hi-Cool`` heat pumps.

  12. Product suitable for the storage and conveyance of thermal energy

    SciTech Connect

    Babin, L.; Clausse, D.

    1981-09-01

    This invention concerns the storage and conveyance of thermal energy at low temperature, by using the latent heat produced by a substance during changes of state. This substance consists of a salt producing considerable latent heat during change of state, such as NA/sub 2/SO/sub 4/, 10 H/sub 2/O, combined closely with a nucleating agent such as borax and dispersed in an oil to which an emulsifying agent has been added. This product is particularly suitable for storage of solar energy at low temperature and for heating of enclosed areas.

  13. Literature review of market studies of thermal energy storage

    SciTech Connect

    Hattrup, M.P.

    1988-02-01

    This report presents the results of a review of market studies of thermal energy storage (TES). This project was conducted by Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE). PNL staff reviewed and consolidated the findings of existing TES market studies conducted in the industrial, commercial, and residential sectors. The purpose of this project was to review and assess previous work and to use the information obtained to help provide direction for future technology transfer planning activities and to identify additional economic research needed within those three sectors. 37 refs.

  14. Thermal energy storage technologies for heating and cooling applications

    NASA Astrophysics Data System (ADS)

    Tomlinson, John J.

    1990-12-01

    Recent results from selected thermal energy storage (TES) research activities in Germany and Sweden are discussed. In addition, several new technologies for heating and cooling of buildings and automobiles were reviewed and found to benefit similar efforts in the United states. Details of a meeting with Didier-Werke AG, a leading German ceramics manufacturer who will provide TES media necessary for the United States to complete field tests of an advanced high temperature latent heat storage material, are presented. Finally, an overview of the December 1990 International Energy Agency (IEA) Executive Committee deliberations on TES is presented.

  15. Environmental risk assessment for aquifer thermal energy storage

    SciTech Connect

    Hall, S.H.

    1993-01-01

    This report has been prepared by Pacific Northwest Laboratory at the request of the International Energy Agency (IEA). The US Department of Energy represents the United States in the IEA for Annex IV, the IEA task for research and development in aquifer thermal energy storage (ATES). Installation and operation of an ATES system is necessarily intrusive to ground-water resources. Therefore, governmental authorities usually require an environmental risk assessment to be performed before permission to construct an ATES system is granted. Writing an accurate statement of risk presupposes a knowledge of aquifer and ground-water characteristics and that an engineering feasibility study has taken place. Effective and logical presentation of the results of the risk assessment can expedite the grant of approval. Introductory remarks should address questions regarding why the ATES project has been proposed, what it is expected to accomplish, and what the expected benefits are. Next, the system configuration, including the aquifer, ATES plant, and well field, should be described in terms of size and location, design components, and thermal and hydraulic capacity. The final element of system design, the predicted annual operating cycle, needs to be described in sufficient detail to allow the reviewer to appreciate the net hydraulic, thermal, and hydrochemical effects imposed on the aquifer. Risks may be environmental or legal. Only after a reviewer has been introduced to the proposed system`s design, operation, and scale can risk issues can be identified and weighed against the benefits of the proposed ATES system.

  16. Environmental risk assessment for aquifer thermal energy storage

    SciTech Connect

    Hall, S.H.

    1993-01-01

    This report has been prepared by Pacific Northwest Laboratory at the request of the International Energy Agency (IEA). The US Department of Energy represents the United States in the IEA for Annex IV, the IEA task for research and development in aquifer thermal energy storage (ATES). Installation and operation of an ATES system is necessarily intrusive to ground-water resources. Therefore, governmental authorities usually require an environmental risk assessment to be performed before permission to construct an ATES system is granted. Writing an accurate statement of risk presupposes a knowledge of aquifer and ground-water characteristics and that an engineering feasibility study has taken place. Effective and logical presentation of the results of the risk assessment can expedite the grant of approval. Introductory remarks should address questions regarding why the ATES project has been proposed, what it is expected to accomplish, and what the expected benefits are. Next, the system configuration, including the aquifer, ATES plant, and well field, should be described in terms of size and location, design components, and thermal and hydraulic capacity. The final element of system design, the predicted annual operating cycle, needs to be described in sufficient detail to allow the reviewer to appreciate the net hydraulic, thermal, and hydrochemical effects imposed on the aquifer. Risks may be environmental or legal. Only after a reviewer has been introduced to the proposed system's design, operation, and scale can risk issues can be identified and weighed against the benefits of the proposed ATES system.

  17. Thermal energy conversion by coupled shape memory and piezoelectric effects

    NASA Astrophysics Data System (ADS)

    Zakharov, Dmitry; Lebedev, Gor; Cugat, Orphee; Delamare, Jerome; Viala, Bernard; Lafont, Thomas; Gimeno, Leticia; Shelyakov, Alexander

    2012-09-01

    This work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE ‘machine’ which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE ‘machine’ with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations.

  18. The transfer between electron bulk kinetic energy and thermal energy in collisionless magnetic reconnection

    SciTech Connect

    Lu, San; Lu, Quanming; Huang, Can; Wang, Shui

    2013-06-15

    By performing two-dimensional particle-in-cell simulations, we investigate the transfer between electron bulk kinetic and electron thermal energy in collisionless magnetic reconnection. In the vicinity of the X line, the electron bulk kinetic energy density is much larger than the electron thermal energy density. The evolution of the electron bulk kinetic energy is mainly determined by the work done by the electric field force and electron pressure gradient force. The work done by the electron gradient pressure force in the vicinity of the X line is changed to the electron enthalpy flux. In the magnetic island, the electron enthalpy flux is transferred to the electron thermal energy due to the compressibility of the plasma in the magnetic island. The compression of the plasma in the magnetic island is the consequence of the electromagnetic force acting on the plasma as the magnetic field lines release their tension after being reconnected. Therefore, we can observe that in the magnetic island the electron thermal energy density is much larger than the electron bulk kinetic energy density.

  19. Hydrogeochemical and isotopic tracers for identification of seasonal and long-term over-exploitation of the Pleistocene thermal waters.

    PubMed

    Rman, Nina

    2016-04-01

    The aim of the study was to develop and test an optimal and cost-effective regional quality monitoring system in depleted transboundary low-temperature Neogene geothermal aquifers in the west Pannonian basin. Potential tracers for identification of seasonal and long-term quality changes of the Pleistocene thermal waters were investigated at four multiple-screened wells some 720 to 1570 m deep in Slovenia. These thermal waters are of great balneological value owing to their curative effects and were sampled monthly between February 2014 and January 2015. Linear correlation and regression analyses, ANOVA and Kolmogorov-Smirnov two-sample test for two independent samples were used to determine their seasonal and long-term differences. Temperature, pH, electrical conductivity, redox potential and dissolved oxygen did not identify varying inflow conditions; however, they provided sufficient information to distinguish between the four end-members. Characteristic (sodium) and conservative (chloride) tracers outlined long-term trends in changes in quality but could not differentiate between the seasons. Stable isotopes of δ (18)O and δ (2)H were used to identify sequential monthly and long-term trends, and origin and mixing of waters, but failed to distinguish the difference between the seasons. A new local paleo-meteoric water line (δ (2)H = 9.2*δ (18)O + 26.3) was outlined for the active regional groundwater flow system in the Pannonian to Pliocene loose sandstone and gravel. A new regression line (δ (2)H = 2.3*δ (18)O-45.2) was calculated for thermomineral water from the more isolated Badenian to Lower Pannonian turbiditic sandstone, indicating dilution of formation water. Water composition was generally stable over the 1-year period, but long-term trends indicate that changes in quality occur, implying deterioration of the aquifers status.

  20. THERMAL-ENERGY STORAGE IN A DEEP SANDSTONE AQUIFER IN MINNESOTA: FIELD OBSERVATIONS AND THERMAL ENERGY-TRANSPORT MODELING.

    USGS Publications Warehouse

    Miller, R.T.

    1986-01-01

    A study of the feasibility of storing heated water in a deep sandstone aquifer in Minnesota is described. The aquifer consists of four hydraulic zones that are areally anisotropic and have average hydraulic conductivities that range from 0. 03 to 1. 2 meters per day. A preliminary axially symmetric, nonisothermal, isotropic, single-phase, radial-flow, thermal-energy-transport model was constructed to investigate the sensitivity of model simulation to various hydraulic and thermal properties of the aquifer. A three-dimensional flow and thermal-energy transport model was constructed to incorporate the areal anisotropy of the aquifer. Analytical solutions of equations describing areally anisotropic groundwater flow around a doublet-well system were used to specify model boundary conditions for simulation of heat injection. The entire heat-injection-testing period of approximately 400 days was simulated. Model-computed temperatures compared favorably with field-recorded temperatures, with differences of no more than plus or minus 8 degree C. For each test cycle, model-computed aquifer thermal efficiency, defined as total heat withdrawn divided by total heat injected, was within plus or minus 2% of the field-calculated values.

  1. Numerical Modeling of a Shallow Borehole Thermal Energy Storage System

    NASA Astrophysics Data System (ADS)

    Catolico, N.; Ge, S.; Lu, N.; McCartney, J. S.

    2014-12-01

    Borehole thermal energy storage (BTES) combined with solar thermal energy harvesting is an economic technological system to garner and store energy as well as an environmentally-sustainable alternative for the heating of buildings. The first community-scale BTES system in North America was installed in 2007 in the Drake Landing Solar Community (DLSC), about 35 miles south of Calgary, Canada. The BTES system involves direct circulation of water heated from solar thermal panels in the summer into a storage tank, after which it is circulate within an array of 144 closed-loop geothermal heat exchangers having a depth of 35 m and a spacing of 2.5 m. In the winter the circulation direction is reversed to supply heat to houses. Data collection over a six year period indicates that this system can supply more than 90% of the winter heating energy needs for 52 houses in the community. One major challenge facing the BTES system technology is the relatively low annual efficiency, i.e., the ratio of energy input and output is in the range of 15% to 40% for the system in Drake Landing. To better understand the working principles of BTES and to improve BTES performance for future applications at larger scales, a three-dimensional transient coupled fluid and heat transfer model is established using TOUGH2. The time-dependent injection temperatures and circulation rate measured over the six years of monitoring are used as model input. The simulations are calibrated using soil temperature data measured at different locations over time. The time-dependent temperature distributions within the borehole region agree well with the measured temperatures for soil with an intrinsic permeability of 10e-19 m2, an apparent thermal conductivity of 2.03 W/m°C, and a volumetric heat capacity of 2.31 MJ/m-3°C. The calibrated model serves as the basis for a sensitivity analysis of soil and operational parameters on BTES system efficiency preformed with TOUGH2. Preliminary results suggest 1) BTES

  2. Thermal Energy Storage in a Confined Aquifer: Second Cycle

    NASA Astrophysics Data System (ADS)

    Molz, F. J.; Parr, A. D.; Andersen, P. F.

    1981-06-01

    During the first 6-month injection-storage-recovery cycle of the Auburn University Aquifer Thermal Energy Storage Project, water pumped from an upper supply aquifer was heated to an average temperature of 55°C with an oil-fired boiler and then injected into a lower storage aquifer. Injection and recovery temperatures, flow rates, and temperatures at six depths in 10 observation wells and hydraulic heads in seven wells were recorded twice daily. The second-cycle injection, which was performed in a manner similar to the first, began on September 23, 1978, and continued until November 25, 1978, when 58,010 m3 of water had been pumped into the storage aquifer. The major problem experienced during the first cycle, a clogging injection well, was reduced by regular backwashing. This was done 8 times during injection and resulted in a 24% average injection rate increase compared to the first cycle. A 63-day storage period ended on January 27, 1979, and production of hot water began with an initial temperature of 54°C. By March 23 this temperature had dropped to 33°C, with 66,400 m3 of water and 76% of the injected thermal energy recovered. This compares to 66% recovery during the first cycle over the same drop in production temperature. Production of hot water continued until April 20, at which time 100,100 m3 of water and 89% of the injected thermal energy was recovered at a final production temperature of 27.5°C. During the second cycle, measurements were made of relative land subsidence and rebound to a precision approaching 0.1 mm. The surface elevation near the injection well rose 4 mm during injection, fell during storage, and fell more rapidly toward its original elevation during production. This movement was due to thermal expansion and contraction rather than to effects caused by head changes in the storage aquifer.

  3. Analysis of Short-Term Closure of the Surface Energy Balance in Different Seasons

    NASA Astrophysics Data System (ADS)

    Cava, D.; Contini, D.; Donateo, A.; Martano, P.

    2007-05-01

    A correct determination of the surface energy balance is an important quality test for measurements of turbulent surface fluxes. The energy balance is often not closed especially in non-homogeneous terrain or in presence of orographic obstacles. Daily energy budget is more easily balanced, because of the contribution of energy residuals of opposite sign; however short-term closure is rarely obtained. What distinguishes this study from previous ones is the effort to close short-term energy budget, and to explore the factors that mainly affect the energy imbalance during the day. To this aim we analysed data sets from southern Italy collected above a semiarid terrain during summer and fall seasons. Our analysis has shown that the global closure rate significantly improves after the correction for the error dependent on the ultrasonic anemometer angle of attack and for the error dependent on the heat storage into the soil. Furthermore a significant reduction of short-term energy residual results by taking into account the contribution to the transport by `large scale motions'. The obtained results are independent from the net incoming radiation.

  4. Seasonal variability of antioxidant biomarkers and energy reserves in the freshwater gammarid Gammarus roeseli.

    PubMed

    Sroda, Sophie; Cossu-Leguille, Carole

    2011-04-01

    In gammarids, behavioural and biochemical biomarkers are commonly used in ecotoxicological studies. In our study, we have investigated seasonal variations of several biochemical biomarkers in Gammarus roeseli, a freshwater species. Organisms were sampled monthly over a 1-year period. Gender was distinguished to measure antioxidant enzyme activities like total glutathione peroxidase (GPxtot), selenium-dependent glutathione peroxidase (SeGPx) and catalase enzymes, lipoperoxidation end-product (malondialdehyde, MDA), and energy reserves with protein and lipid contents. In the same time, usual water physico-chemical parameters were measured at the sampling site. A based-gender difference was observed for parameters related to oxidative stress. Females showed higher antioxidant enzyme activities and lower MDA level than males. Parameters related to oxidative stress and energy reserves appeared correlated with temperature and physiological status of organisms. Females GPx activities were lower in autumn and winter when no breeding occurred. In both gender, MDA levels were correlated with temperature with an increase of lipoperoxidation in summer. Lipid contents were the lowest in summer and the highest in winter, probably due to the reproductive status of organisms and their feeding behaviour. Gender-based differences of biochemical parameters suggest a specific sensitivity of males and females in ecotoxicological experiments. Moreover, organisms could be more vulnerable in summer when MDA levels are high and energy reserves low. Deleterious effect of xenobiotics would be different with gender and season.

  5. Seasonal Dynamics of Water, Carbon, and Energy Flux in Mesquite Forest: Project Overview and Preliminary Results

    NASA Astrophysics Data System (ADS)

    Williams, D. G.; Scott, R.; Lin, G.; Martens, D.; Watts, C.; Goodrich, D.; Garatuza, J.; Rodriguez, J.; Edwards, E.; Hultine, K.; Yepez, E.; Ellsworth, P.; Cable, W.; vanHaren, J.; Pierce, D.

    2001-12-01

    Mesquite is the dominant woody plant in floodplain environments of warm deserts in the southwestern US and thus plays a central role in biogeochemical cycling and energy exchange at landscape and potentially regional scales. Our project investigates the biotic and abiotic controls over seasonal dynamics of energy exchange, CO2 uptake and release, and evapotranspiration within a mature mesquite forest on the San Pedro River floodplain in southeastern Arizona. The growing season in the upper San Pedro River basin is punctuated by a very hot, dry period in early summer followed by monsoon rains that stimulate prolific growth of under story C4 grasses. Our general objectives are to determine the impact of summer rains on net ecosystem CO2 exchange (NEE), evapotranspiration (ET), energy fluxes and soil nutrient cycling, and to understand and model component fluxes in these two-layered canopies. We are continuously monitoring NEE and ET using an eddy covariance system mounted on a 14-m tall tower at the site. Three intensive field campaigns (pre-, mid-, and post-monsoon) included measurements of eddy fluxes beneath the mesquite canopy, mesquite sap flow, mesquite leaf area index, mesquite and grass water sources and stomatal conductance, soil moisture distribution, soil respiration, soil carbon and nitrogen pools, and isotopic composition of CO2 and water vapor within and above the canopy boundary layer. This talk will highlight some of the important findings from the first year of this project. >http://www.tucson.ars.ag.gov/~russell/mesquitehome.htm

  6. Thermal Energy Harvesting Using Pyroelectric and Piezoelectric Effect

    NASA Astrophysics Data System (ADS)

    Kang, Miwon; Yeatman, Eric M.

    2016-11-01

    This paper presents a prototype of a thermal energy harvesting mechanism using both pyroelectric and piezoelectric effect. Thermal energy is one of abundant energy sources from various processes. Waste heat from a chip on a circuit board of the electronic device involves temperature differences from a few degrees C to over 100 °C. Therefore, 95 °C of a heat reservoir was used in this study. A repetitive time-dependant temperature variation is applied by a linear sliding table. The influence of heat conditions was investigated, by changing velocity and frequency of this linear sliding table. This energy harvesting mechanism employs Lead Zirconate Titanate (PZT-5H), a bimetal beam and two neodymium magnets. The pyroelectric effect is caused by a time-dependent temperature variation, and the piezoelectric effect is caused by stress from deformation of the bimetal. A maximum power output 0.54 μW is obtained at an optimal condition when the load resistance is 610 kΩ.

  7. The seasonal CO2 cycle on Mars - An application of an energy balance climate model

    NASA Technical Reports Server (NTRS)

    James, P. B.; North, G. R.

    1982-01-01

    Energy balance climate models of the Budyko-Sellers variety are applied to the carbon-dioxide cycle on Mars. Recent data available from the Viking mission, in particular the seasonal pressure variations measured by Viking landers, are used to constrain the models. No set of parameters was found for which a one-dimensional model parameterized in terms of ground temperature gave an adequate fit to the observed pressure variations. A modified, two-dimensional model including the effects of dust storms and the polar hood reasonably reproduces the pressure curve, however. The implications of these results for Martian climate changes are discussed.

  8. Differences between seasonal and mean annual energy balance model calculations of climate and climate sensitivity

    NASA Technical Reports Server (NTRS)

    North, G. R.; Coakley, J. A., Jr.

    1979-01-01

    The paper extends a simple Budyko-Sellers mean annual energy balance climate model with diffusive transport to include a seasonal cycle. In the model the latitudinal distribution of the zonal average surface temperature is represented by Legendre polynomials and its time-dependence by a Fourier sine-cosine series, and it has three parameters adjusted so that the observed amplitudes of the Northern Hemisphere zonal mean surface temperature are recovered. The seasonal model is used to reveal how the annual mean climate and the sensitivity to changes in incident radiation differ from the predictions obtained with the corresponding mean annual model. The distribution of the incident solar radiation in the models is shown to be insensitive to changes in the eccentricity and the longitude of perihelion and sensitive only to changes in the obliquity of the earth, and for past orbital changes both the seasonal and the mean annual model fail to produce glacial advances of the magnitude that are thought to have occurred.

  9. Numerical modeling of Thermal Response Tests in Energy Piles

    NASA Astrophysics Data System (ADS)

    Franco, A.; Toledo, M.; Moffat, R.; Herrera, P. A.

    2013-05-01

    Nowadays, thermal response tests (TRT) are used as the main tools for the evaluation of low enthalpy geothermal systems such as heat exchangers. The results of TRT are used for estimating thermal conductivity and thermal resistance values of those systems. We present results of synthetic TRT simulations that model the behavior observed in an experimental energy pile system, which was installed at the new building of the Faculty of Engineering of Universidad de Chile. Moreover, we also present a parametric study to identify the most influent parameters in the performance of this type of tests. The modeling was developed using the finite element software COMSOL Multiphysics, which allows the incorporation of flow and heat transport processes. The modeled system consists on a concrete pile with 1 m diameter and 28 m deep, which contains a 28 mm diameter PEX pipe arranged in a closed circuit. Three configurations were analyzed: a U pipe, a triple U and a helicoid shape implemented at the experimental site. All simulations were run considering transient response in a three-dimensional domain. The simulation results provided the temperature distribution on the pile for a set of different geometry and physical properties of the materials. These results were compared with analytical solutions which are commonly used to interpret TRT data. This analysis demonstrated that there are several parameters that affect the system response in a synthetic TRT. For example, the diameter of the simulated pile affects the estimated effective thermal conductivity of the system. Moreover, the simulation results show that the estimated thermal conductivity for a 1 m diameter pile did not stabilize even after 100 hours since the beginning of the test, when it reached a value 30% below value used to set up the material properties in the simulation. Furthermore, we observed different behaviors depending on the thermal properties of concrete and soil. According to the simulations, the thermal

  10. PCM/ graphite foam composite for thermal energy storage device

    NASA Astrophysics Data System (ADS)

    Guo, C. X.; Ma, X. L.; Yang, L.

    2015-07-01

    Numerical studies are proposed to predict and investigate the thermal characteristics of a thermal storage device consists of graphite foam matrix saturated with phase change material, PCM. The composite (graphite foam matrix saturated with PCM) is prepared by impregnation method under vacuum condition, and then is introduced into a cylindrical shell and tube device while it experiences its heat from an inner tube fluid. The two-dimensional numerical simulation is performed using the volume averaging technique; while the phases change process is modelled using the enthalpy porosity method. A series of numerical calculations have been done in order to analyze the influence of fluid operating conditions on the melting process of the paraffin/graphite foam. The results are given in terms of temperature or liquid fraction time history in paraffin/graphite foam composite, which show that the heat transfer rate of the device is effectively improved due to the high thermal conductivity of graphite foams. Therefore, paraffin/graphite foam composite can be considered as suitable candidates for latent heat thermal energy storage device.

  11. Characterization of an energy storage capacitor in abnormal thermal environments

    SciTech Connect

    Edwards, L.R.; Chen, K.C.; Baron, R.V.

    2000-01-05

    There are applications of high-voltage, energy-storage, capacitors where it is desirable that the energy storage capability can be reliably and predictably negated in abnormal environments such as fire. This property serves as a safety feature to prevent events of unintended consequence. The present paper describes studies of the thermal response characteristics of a cylindrically wound, discrete Mylar film/foil capacitor design. The experimental setups that simulate fires will be presented. Three different heat input geometries were employed: uniform radial input, spot radial input, and axial input. Heat input was controlled via feedback system to maintain specific temperature ramp rates. Both capacitor voltage and current were monitored during the thermal excursion to ascertain the failure temperature, i.e. when the capacitor permanently shorts. Temperature of failure data is presented for the three heat input cases along with a statistical analysis of the results and application implications. The physics of failure will be described in terms of the thermal/mechanical properties of the Mylar.

  12. Sodium-based hydrides for thermal energy applications

    NASA Astrophysics Data System (ADS)

    Sheppard, D. A.; Humphries, T. D.; Buckley, C. E.

    2016-04-01

    Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed.

  13. Advanced Reactors Thermal Energy Transport for Process Industries

    SciTech Connect

    P. Sabharwall; S.J. Yoon; M.G. McKellar; C. Stoots; George Griffith

    2014-07-01

    The operation temperature of advanced nuclear reactors is generally higher than commercial light water reactors and thermal energy from advanced nuclear reactor can be used for various purposes such as liquid fuel production, district heating, desalination, hydrogen production, and other process heat applications, etc. Some of the major technology challenges that must be overcome before the advanced reactors could be licensed on the reactor side are qualification of next generation of nuclear fuel, materials that can withstand higher temperature, improvement in power cycle thermal efficiency by going to combined cycles, SCO2 cycles, successful demonstration of advanced compact heat exchangers in the prototypical conditions, and from the process side application the challenge is to transport the thermal energy from the reactor to the process plant with maximum efficiency (i.e., with minimum temperature drop). The main focus of this study is on doing a parametric study of efficient heat transport system, with different coolants (mainly, water, He, and molten salts) to determine maximum possible distance that can be achieved.

  14. Equilibrium statistical-thermal models in high-energy physics

    NASA Astrophysics Data System (ADS)

    Tawfik, Abdel Nasser

    2014-05-01

    We review some recent highlights from the applications of statistical-thermal models to different experimental measurements and lattice QCD thermodynamics that have been made during the last decade. We start with a short review of the historical milestones on the path of constructing statistical-thermal models for heavy-ion physics. We discovered that Heinz Koppe formulated in 1948, an almost complete recipe for the statistical-thermal models. In 1950, Enrico Fermi generalized this statistical approach, in which he started with a general cross-section formula and inserted into it, the simplifying assumptions about the matrix element of the interaction process that likely reflects many features of the high-energy reactions dominated by density in the phase space of final states. In 1964, Hagedorn systematically analyzed the high-energy phenomena using all tools of statistical physics and introduced the concept of limiting temperature based on the statistical bootstrap model. It turns to be quite often that many-particle systems can be studied with the help of statistical-thermal methods. The analysis of yield multiplicities in high-energy collisions gives an overwhelming evidence for the chemical equilibrium in the final state. The strange particles might be an exception, as they are suppressed at lower beam energies. However, their relative yields fulfill statistical equilibrium, as well. We review the equilibrium statistical-thermal models for particle production, fluctuations and collective flow in heavy-ion experiments. We also review their reproduction of the lattice QCD thermodynamics at vanishing and finite chemical potential. During the last decade, five conditions have been suggested to describe the universal behavior of the chemical freeze-out parameters. The higher order moments of multiplicity have been discussed. They offer deep insights about particle production and to critical fluctuations. Therefore, we use them to describe the freeze-out parameters

  15. Thermal energy storage. [by means of chemical reactions

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.

    1975-01-01

    The principles involved in thermal energy storage by sensible heat, chemical potential energy, and latent heat of fusion are examined for the purpose of evolving selection criteria for material candidates in the low ( 0 C) and high ( 100 C) temperature ranges. The examination identifies some unresolved theoretical considerations and permits a preliminary formulation of an energy storage theory. A number of candidates in the low and high temperature ranges are presented along with a rating of candidates or potential candidates. A few interesting candidates in the 0 to 100 C region are also included. It is concluded that storage by means of reactions whose reversibility can be controlled either by product removal or by catalytic means appear to offer appreciable advantages over storage with reactions whose reversability cannot be controlled. Among such advantages are listed higher heat storage capacities and more favorable options regarding temperatures of collection, storage, and delivery. Among the disadvantages are lower storage efficiencies.

  16. Butterfly micro bilayer thermal energy harvester geometry with improved performances

    NASA Astrophysics Data System (ADS)

    Trioux, E.; Monfray, S.; Basrour, S.

    2016-11-01

    This paper reports the recent progress of a new technology to scavenge thermal energy, implying a double-step transduction through thermal buckling of a bilayer aluminum nitride / aluminum bridge and piezoelectric transduction. A completely new scavenger design is presented, improving greatly its final performance. The butterfly shape reduces the overall device mechanical rigidity, which leads to a decrease of buckling temperatures compared to previously studied rectangular plates. In a first time we compared performances of rectangular and butterfly plates with an equal thickness of Al and AlN. In a second time, with a thicker Al layer than AlN layer, we will study only butterfly structure in terms of output power and buckling temperatures, and compare it to the previous stack.

  17. A survey of manufacturers of solar thermal energy systems

    NASA Technical Reports Server (NTRS)

    Levine, N.; Slonski, M. L.

    1982-01-01

    Sixty-seven firms that had received funding for development of solar thermal energy systems (STES) were surveyed. The effect of the solar thermal technology systems program in accelerating (STES) were assessed. The 54 firms still developing STES were grouped into a production typology comparing the three major technologies with three basic functions. It was discovered that large and small firms were developing primarily central receiver systems, but also typically worked on more than one technology. Most medium-sized firms worked only on distributed systems. Federal support of STES was perceived as necessary to allow producers to take otherwise unacceptable risks. Approximately half of the respondents would drop out of STES if support were terminated, including a disproportionate number of medium-sized firms. A differentiated view of the technology, taking into account differing firm sizes and the various stages of technology development, was suggested for policy and planning purposes.

  18. Development of thermal energy storage materials for biomedical applications.

    PubMed

    Shukla, A; Sharma, Atul; Shukla, Manjari; Chen, C R

    2015-01-01

    The phase change materials (PCMs) have been utilized widely for solar thermal energy storage (TES) devices. The quality of these materials to remain at a particular temperature during solid-liquid, liquid-solid phase transition can also be utilized for many biomedical applications as well and has been explored in recent past already. This study reports some novel PCMs developed by them, along with some existing PCMs, to be used for such biomedical applications. Interestingly, it was observed that the heating/cooling properties of these PCMs enhance the quality of a variety of biomedical applications with many advantages (non-electric, no risk of electric shock, easy to handle, easy to recharge thermally, long life, cheap and easily available, reusable) over existing applications. Results of the present study are quite interesting and exciting, opening a plethora of opportunities for more work on the subject, which require overlapping expertise of material scientists, biochemists and medical experts for broader social benefits.

  19. On thermal properties of hard rocks as a host environment of an underground thermal energy storage

    NASA Astrophysics Data System (ADS)

    Novakova, L.; Hladky, R.; Broz, M.; Novak, P.; Lachman, V.; Sosna, K.; Zaruba, J.; Metelkova, Z.; Najser, J.

    2013-12-01

    With increasing focus on environmentally friendly technologies waste heat recycling became an important issue. Under certain circumstances subsurface environment could be utilized to accommodate relatively large quantity of heat. Industrial waste heat produced during warm months can be stored in an underground thermal energy storage (UTES) and used when needed. It is however a complex task to set up a sustainable UTES for industrial scale. Number of parameters has to be studied and evaluated by means of thermohydromechanical and chemical coupling (THMC) before any UTES construction. Thermal characteristics of various rocks and its stability under thermal loading are amongst the most essential. In the Czech Republic study two complementary projects THMC processes during an UTES operation. The RESEN project (www.resen.cz) employs laboratory tests and experiments to characterise thermal properties of hard rocks in the Bohemian Massif. Aim of the project is to point out the most suitable rock environment in the Bohemian Massif for moderate to ultra-high temperature UTES construction (Sanyal, 2005). The VITA project (www.geology.cz/mokrsko) studies THM coupling in non-electrical temperature UTES using long term in-situ experiment. In both projects thermal properties of rocks were studied. Thermal conductivity and capacity were measured on rock samples. In addition an influence of increasing temperature and moisture content was considered. Ten hard rocks were investigated. The set included two sandstones, two ignibrites, a melaphyr, a syenite, two granites, a gneiss and a serpentinite. For each rock there were measured thermal conductivity and capacity of at least 54 dried samples. Subsequently, the samples were heated up to 380°C in 8 hours and left to cool down. Thermal characteristics were measured during the heating period and after the sample reached room temperature. Heating and cooling cycle was repeated 7 to 10 times to evaluate possible UTES-like degradation of

  20. Thermal Energy Corporation Combined Heat and Power Project

    SciTech Connect

    Turner, E. Bruce; Brown, Tim; Mardiat, Ed

    2011-12-31

    To meet the planned heating and cooling load growth at the Texas Medical Center (TMC), Thermal Energy Corporation (TECO) implemented Phase 1 of a Master Plan to install an additional 32,000 tons of chilled water capacity, a 75,000 ton-hour (8.8 million gallon) Thermal Energy Storage (TES) tank, and a 48 MW Combined Heat and Power (CHP) system. The Department of Energy selected TMC for a $10 million grant award as part of the Financial Assistance Funding Opportunity Announcement, U.S. Department of Energy National Energy Technology, Recovery Act: Deployment of Combined Heat and Power (CHP) Systems, District Energy Systems, Waste Energy Recovery Systems, and Efficiency Industrial Equipment Funding Opportunity Number: DE-FOA-0000044 to support the installation of a new 48 MW CHP system at the TMC located just outside downtown Houston. As the largest medical center in the world, TMC is home to many of the nation's best hospitals, physicians, researchers, educational institutions, and health care providers. TMC provides care to approximately six million patients each year, and medical instruction to over 71,000 students. A medical center the size of TMC has enormous electricity and thermal energy demands to help it carry out its mission. Reliable, high-quality steam and chilled water are of utmost importance to the operations of its many facilities. For example, advanced medical equipment, laboratories, laundry facilities, space heating and cooling all rely on the generation of heat and power. As result of this project TECO provides this mission critical heating and cooling to TMC utilizing a system that is both energy-efficient and reliable since it provides the capability to run on power independent of the already strained regional electric grid. This allows the medical center to focus on its primary mission providing top quality medical care and instruction without worrying about excessive energy costs or the loss of heating and cooling due to the risk of power

  1. Solar energy system performance evaluaton: Seasonal report for Solaron-Akron, Akron, Ohio

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The operational and thermal performance of the solar energy system by Solaron Corporation is described. The system was designed to provide an 1940 square foot floor area with space heating and domestic hot water for a dual-level single family residence in Akron, Ohio. The solar energy system uses air as the heat transport medium, has a 546 square foot flat plate collector array subsystem, a 270 cubic foot rock thermal storage bin subsystem, a domestic hot water preheat tank, pumps, controls and transport lines. In general, the performance of the Solaron Akron solar energy system was somewhat difficult to assess for the November 1978 through October 1979 time period. The problems relating to the control systems, various solar energy leakages, air flow correction factors and instrumentation cause a significant amount of subjectivity to be involved in the performance assessment for this solar energy system. Had these problems not been present, it is felt that this system would have exhibited a resonably high level of measured performance.

  2. Solar energy system performance evaluaton: Seasonal report for Solaron-Akron, Akron, Ohio

    NASA Astrophysics Data System (ADS)

    1980-05-01

    The operational and thermal performance of the solar energy system by Solaron Corporation is described. The system was designed to provide an 1940 square foot floor area with space heating and domestic hot water for a dual-level single family residence in Akron, Ohio. The solar energy system uses air as the heat transport medium, has a 546 square foot flat plate collector array subsystem, a 270 cubic foot rock thermal storage bin subsystem, a domestic hot water preheat tank, pumps, controls and transport lines. In general, the performance of the Solaron Akron solar energy system was somewhat difficult to assess for the November 1978 through October 1979 time period. The problems relating to the control systems, various solar energy leakages, air flow correction factors and instrumentation cause a significant amount of subjectivity to be involved in the performance assessment for this solar energy system. Had these problems not been present, it is felt that this system would have exhibited a resonably high level of measured performance.

  3. Feasibility study of thermal energy harvesting using lead free pyroelectrics

    NASA Astrophysics Data System (ADS)

    Karim, Hasanul; Sarker, Md Rashedul H.; Shahriar, Shaimum; Arif Ishtiaque Shuvo, Mohammad; Delfin, Diego; Hodges, Deidra; (Bill Tseng, Tzu-Liang; Roberson, David; Love, Norman; Lin, Yirong

    2016-05-01

    Energy harvesting has significant potential for applications in energizing wireless sensors and charging energy storage devices. To date, one of the most widely investigated materials for mechanical and thermal energy harvesting is lead zirconate titanate (PZT). However, lead has detrimental effects on the environment and on health. Hence, alternative materials are required for this purpose. In this paper, a lead free material, lithium niobate (LNB) is investigated as a potential material for pyroelectric energy harvesting. Although its theoretical pyroelectric properties are lower compared to PZT, it has better properties than other lead free alternatives such as ZnO. In addition, LNB has a high Curie temperature of about 1142 °C, which makes it applicable for high temperature energy harvesting, where other pyroelectric ceramics are not suitable. Herein, an energy harvesting and storage system composed of a single crystal LNB and a porous carbon-based super-capacitor was investigated. It is found that with controlled heating and cooling, a single wafer of LNB (75 mm diameter and 0.5 mm thickness) could generate 437.72 nW cm-3 of power and it could be used to charge a super-capacitor with a charging rate of 2.63 mV (h cm3)-1.

  4. Integrating seasonal optical and thermal infrared spectra to characterize urban impervious surfaces with extreme spectral complexity: a Shanghai case study

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yao, Xinfeng; Ji, Minhe

    2016-01-01

    Despite recent rapid advancement in remote sensing technology, accurate mapping of the urban landscape in China still faces a great challenge due to unusually high spectral complexity in many big cities. Much of this complication comes from severe spectral confusion of impervious surfaces with polluted water bodies and bright bare soils. This paper proposes a two-step land cover decomposition method, which combines optical and thermal spectra from different seasons to cope with the issue of urban spectral complexity. First, a linear spectral mixture analysis was employed to generate fraction images for three preliminary endmembers (high albedo, low albedo, and vegetation). Seasonal change analysis on land surface temperature induced from thermal infrared spectra and coarse component fractions obtained from the first step was then used to reduce the confusion between impervious surfaces and nonimpervious materials. This method was tested with two-date Landsat multispectral data in Shanghai, one of China's megacities. The results showed that the method was capable of consistently estimating impervious surfaces in highly complex urban environments with an accuracy of R2 greater than 0.70 and both root mean square error and mean average error less than 0.20 for all test sites. This strategy seemed very promising for landscape mapping of complex urban areas.

  5. Site-specific investigations on aquifer thermal energy storage for space and process cooling

    NASA Astrophysics Data System (ADS)

    Brown, D. R.

    1991-08-01

    The Pacific Northwest Laboratory (PNL) has completed three preliminary site-specific feasibility studies that investigated aquifer thermal energy storage (ATES) for reducing space and process cooling costs. Chilled water stored in an ATES system could be used to meet all or part of the process and/or space cooling loads at the three facilities investigated. Seasonal or diurnal chill ATES systems could be significantly less expensive than a conventional electrically-driven, load-following chiller system at one of the three sites, depending on the cooling water loop return temperature and presumed future electricity escalation rate. For the other two sites investigated, a chill ATES system would be economically competitive with conventional chillers if onsite aquifer characteristics were improved. Well flow rates at one of the sites were adequate, but the expected thermal recovery efficiency was too low. The reverse of this situation was found at the other site, where the thermal recovery efficiency was expected to be adequate, but well flow rates were too low.

  6. Discharge Flux Variability in Stored Thermal Energy Cookstoves

    NASA Astrophysics Data System (ADS)

    Bryant, Michael James

    A thermal analysis and test is performed to determine flux and temperature variability for Phase change thermal energy to investigation feasibility of use in a Stored Thermal Energy Cookstove (STEC). The phase change material (PCM) NaNO3-KNO3 Eutectic (52:48) Solar Salt is identified for energy storage in STEC due to a melting temperature of 222°C which is deemed appropriate for use in cooking up to temperatures of 200°C +/- 20°C. 1-D planar and cylindrical analytical multiphase solutions are correlated with a transient non-linear ANSYS Finite Element Model (FEM). 1-D idealized models of planar and cylindrical analytical multiphase solutions show the flux stability of cylindrical solidification is twice that of planar solidification. Flux drops a linear average of 0.5%/min in the last half hour of a one hour cooking session in cylindrical solidification vs 1%/min in planar solidification under a constant temperature (dirichlet) boundary condition of 42°C below the melting point of the PCM. Solidification progresses more quickly in the planar case yielding a solid PCM thickness of 3.3 cm after one hour vs 2.4 cm in the cylindrical case. A test is performed on a simplified simple STEC apparatus to investigate cooling rates of the cooking surface while boiling water. 0.5L of water is brought to boil from room temperature with a linear average cooking surface flux of 21,000 W/m2 and a cooking surface cooling rate of 3.8°C/min. Results show increasing the thermal conductivity of the PCM and reducing the total thickness of the solidifying PCM layer before and after discharge will reduce cooling rates, improve stability of the flux delivery device, and increase feasibility of use. Pursuing lower flux cooking and non-cooking applications may increase likelihood of adoption by reducing thermal gradients during discharge. A proposal to explore further development of STEC to aid adoption is discussed.

  7. SERI solar energy storage program

    NASA Astrophysics Data System (ADS)

    Baylin, F.; Copeland, R. J.; Kotch, A.; Kriz, T.; Luft, W.; Nix, R. G.; Wright, J. O.

    1982-05-01

    Thermal energy storage technologies are identified for specific solar thermal applications. The capabilities and limitations of direct-contact thermal storage and thermochemical energy storage and transport are examined. Storage of energy from active solar thermal systems for industrial process heat and the heating of buildings is analyzed and seasonal energy storage is covered. The coordination of numerous thermal energy storage research and development activities is described.

  8. Improved Water and Energy Management Utilizing Seasonal to Interannual Hydroclimatic Forecasts

    NASA Astrophysics Data System (ADS)

    Arumugam, S.; Lall, U.

    2014-12-01

    Seasonal to interannual climate forecasts provide valuable information for improving water and energy management. Given that the climatic attributes over these time periods are typically expressed as probabilistic information, we propose an adaptive water and energy management framework that uses probabilistic inflow forecasts to allocate water for uses with pre-specified reliabilities. To ensure that the system needs are not compromised due to forecast uncertainty, we propose uncertainty reduction using model combination and based on a probabilistic constraint in meeting the target storage. The talk will present findings from recent studies from various basins that include (a) role of multimodel combination in reducing the uncertainty in allocation (b) relevant system characteristics that improve the utility of forecasts, (c) significance of streamflow forecasts in promoting interbasin transfers and (d) scope for developing power demand forecasts utilizing temperature forecasts. Potential for developing seasonal nutrient forecasts using climate forecasts for supporting water quality trading will also be presented. Findings and synthesis from the panel discussion from the recently concluded AGU chapman conference on "Seaonal to Interannual Hydroclimatic Forecasts and Water Management" will also be summarized.

  9. Evaluation of diurnal thermal energy storage combined with cogeneration systems

    NASA Astrophysics Data System (ADS)

    Somasundaram, S.; Brown, D. R.; Drost, M. K.

    1992-11-01

    This report describes the results of an evaluation of thermal energy storage (TES) integrated with simple gas turbine cogeneration systems. The TES system captures and stores thermal energy from the gas turbine exhaust for immediate or future generation of process heat. Integrating thermal energy storage with conventional cogeneration equipment increases the initial cost of the combined system; but, by decoupling electric power and process heat production, the system offers the following significant advantages: (1) electric power can be generated on demand, irrespective of the process heat load profile, thus increasing the value of the power produced; (2) although supplementary firing could be used to serve independently varying electric and process heat loads, this approach is inefficient. Integrating TES with cogeneration can serve the two independent loads while firing all fuel in the gas turbine. The study evaluated the cost of power produced by cogeneration and cogeneration/TES systems designed to serve a fixed process steam load. The value of the process steam was set at the levelized cost estimated for the steam from a conventional stand-alone boiler. Power costs for combustion turbine and combined-cycle power plants were also calculated for comparison. The results indicated that peak power production costs for the cogeneration/TES systems were between 25 and 40 percent lower than peak power costs estimated for a combustion turbine and between 15 and 35 percent lower than peak power costs estimated for a combined-cycle plant. The ranges reflect differences in the daily power production schedule and process steam pressure/temperature assumptions for the cases evaluated. Further cost reductions may result from optimization of current cogeneration/TES system designs and improvement in TES technology through future research and development.

  10. Solar-thermal-energy collection/storage-pond system

    DOEpatents

    Blahnik, D.E.

    1982-03-25

    A solar thermal energy collection and storage system is disclosed. Water is contained, and the water surface is exposed directly to the sun. The central part of an impermeable membrane is positioned below the water's surface and above its bottom with a first side of the membrane pointing generally upward in its central portion. The perimeter part of the membrane is placed to create a watertight boundary separating the water into a first volume which is directly exposable to the sun and which touches the membranes first side, and a second volumn which touches the membranes second side. A salt is dissolved in the first water volume.

  11. Carbon dioxide release from ocean thermal energy conversion (OTEC) cycles

    SciTech Connect

    Green, H.J. ); Guenther, P.R. )

    1990-09-01

    This paper presents the results of recent measurements of CO{sub 2} release from an open-cycle ocean thermal energy conversion (OTEC) experiment. Based on these data, the rate of short-term CO{sub 2} release from future open-cycle OTEC plants is projected to be 15 to 25 times smaller than that from fossil-fueled electric power plants. OTEC system that incorporate subsurface mixed discharge are expected to result in no long-term release. OTEC plants can significantly reduce CO{sub 2} emissions when substituted for fossil-fueled power generation. 12 refs., 4 figs., 3 tabs.

  12. Thermal energy storage units for solar electric power plants

    NASA Astrophysics Data System (ADS)

    Gudkov, V. I.; Chakalev, K. N.

    Several types of heat storage units for solar power plants with thermodynamic cycles of energy conversion are examined, including specific-heat units (particularly water-vapor devices), thermochemical units, and phase-change units. The dependence of specific capital costs for heat storage units upon time of operation is discussed, and particular consideration is give to types of connections of specific-heat units into the thermal circuit of a power plant, and to a phase-change unit that uses a heat pipe for internal heat transport.

  13. Thermal energy storage systems using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.

    1980-01-01

    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  14. Heat transfer research for ocean thermal energy conversion

    SciTech Connect

    Kreith, F.; Bharathan, D.

    1988-02-01

    In this lecture an overview of the heat and mass-transfer phenomena of importance in ocean thermal energy conversion (OTEC) is presented with particular emphasis on open-cycle OTEC systems. Also included is a short historical review of OTEC developments in the past century and a comparison of open and closed-cycle thermodynamics. Finally, results of system analyses, showing the effect of plant size on cost and the near-term potential of using OTEC for combined power production and desalination systems, are briefly discussed.

  15. Heat transfer research for ocean thermal energy conversion

    NASA Astrophysics Data System (ADS)

    Kreith, F.; Bharathan, D.

    1987-03-01

    In this lecture an overview of the heat- and mass-transfer phenomena of importance in ocean thermal energy conversion (OTEC) is presented with particular emphasis on open-cycle OTEC systems. Also included is a short historical review of OTEC developments in the past century and a comparison of open- and closed-cycle thermodynamics. Finally, results of system analyses, showing the effect of plant size on cost and the near-term potential of using OTEC for combined power production and desalination systems are briefly discussed.

  16. Alkali Metal/Salt Thermal-Energy-Storage Systems

    NASA Technical Reports Server (NTRS)

    Phillips, Wayne W.; Stearns, John W.

    1987-01-01

    Proposed thermal-energy-storage system based on mixture of alkali metal and one of its halide salts; metal and salt form slurry of two immiscible melts. Use of slurry expected to prevent incrustations of solidified salts on heat-transfer surfaces that occur where salts alone used. Since incrustations impede heat transfer, system performance improved. In system, charging heat-exchanger surface immersed in lower liquid, rich in halide-salt, phase-charge material. Discharging heat exchanger surface immersed in upper liquid, rich in alkali metal.

  17. Electrochemical energy storage systems for solar thermal applications

    NASA Technical Reports Server (NTRS)

    Krauthamer, S.; Frank, H.

    1980-01-01

    Existing and advanced electrochemical storage and inversion/conversion systems that may be used with terrestrial solar-thermal power systems are evaluated. The status, cost and performance of existing storage systems are assessed, and the cost, performance, and availability of advanced systems are projected. A prime consideration is the cost of delivered energy from plants utilizing electrochemical storage. Results indicate that the five most attractive electrochemical storage systems are the: iron-chromium redox (NASA LeRC), zinc-bromine (Exxon), sodium-sulfur (Ford), sodium-sulfur (Dow), and zinc-chlorine (EDA).

  18. Analysis of dynamic effects in solar thermal energy conversion systems

    NASA Technical Reports Server (NTRS)

    Hamilton, C. L.

    1978-01-01

    The paper examines a study the purpose of which is to assess the performance of solar thermal power systems insofar as it depends on the dynamic character of system components and the solar radiation which drives them. Using a dynamic model, the daily operation of two conceptual solar conversion systems was simulated under varying operating strategies and several different time-dependent radiation intensity functions. These curves ranged from smoothly varying input of several magnitudes to input of constant total energy whose intensity oscillated with periods from 1/4 hour to 6 hours.

  19. Seasonal Variation of turbulent Energy Dissipation Rates in the Polar Mesosphere

    NASA Astrophysics Data System (ADS)

    Singer, W.; Latteck, R.; Becker, E.

    Turbulent energy dissipation rates have been derived from the width of the observed signal spectra obtained with a narrow beam Doppler radar operated at 3 17 MHz in Andenes 69 r N using a computationally intensive correction method to remove contributions from non-turbulent processes Vertical and oblique beams with a minimum half-power full-beam width of 6 6 r are used The radar provides estimates of turbulent energy dissipation rates in an altitude range from 50 to about 90 km with a time resolution of 1 h and a range resolution of 1 km since September 2003 Turbulent energy dissipation rates based on radar observations vary in the order of 2-10 mW kg around 70 km and between about 10 and 200 mW kg around 85 km in dependence on season During the occurrence of strong polar mesosphere winter echoes in January 2005 energy dissipation rates between 30 and about 100 mW kg are observed at altitudes from 55 to 65 km The radar estimates of turbulent energy dissipation rates are in reasonable agreement with climatologically winter and summer data from previous rocket soundings at Andenes as well as with time-resolved results 1-h resolution from the Kuehlungsborn Mechanistic General Circulation Model KMCM model for summer and winter conditions

  20. Water, energy and CO2 exchange over a seasonally flooded forest in the Sahel.

    NASA Astrophysics Data System (ADS)

    Kergoat, L.; Le Dantec, V.; Timouk, F.; Hiernaux, P.; Mougin, E.; Manuela, G.; Diawara, M.

    2014-12-01

    In semi-arid areas like the Sahel, perennial water bodies and temporary-flooded lowlands are critical for a number of activities. In some cases, their existence is simply a necessary condition for human societies to establish. They also play an important role in the water and carbon cycle and have strong ecological values. As a result of the strong multi-decadal drought that impacted the Sahel in the 70' to 90', a paradoxical increase of ponds and surface runoff has been observed ("Less rain, more water in the ponds", Gardelle 2010). In spite of this, there are excessively few data documenting the consequence of such a paradox on the water and carbon cycle. Here we present 2 years of eddy covariance data collected over the Kelma flooded Acacia forest in the Sahel (15.50 °N), in the frame of the AMMA project. The flooded forest is compared to the other major component of this Sahelian landscape: a grassland and a rocky outcrop sites. All sites are involved in the ALMIP2 data/LSM model comparison. The seasonal cycle of the flooded forest strongly departs from the surroundings grassland and bare soil sites. Before the rain season, the forest displays the strongest net radiation and sensible heat flux. Air temperature within the canopy reaches extremely high values. During the flood, it turns to the lowest sensible heat flux. In fact, due to an oasis effect, this flux is negative during the late flood. Water fluxes turn from almost zero in the dry season to strong evaporation during the flood, since it uses additional energy provided by negative sensible heat flux. The eddy covariance fluxes are consistent with sap flow data, showing that the flood greatly increases the length of the growing season. CO2 fluxes over the forest were twice as large as over the grassland, and the growing season was also longer, giving a much larger annual photosynthesis. In view of these data and data over surroundings grasslands and bare soil, as well as data from a long-term ecological

  1. Conceptual design of thermal energy storage systems for near-term electric utility applications

    NASA Technical Reports Server (NTRS)

    Hall, E. W.

    1980-01-01

    Promising thermal energy storage systems for midterm applications in conventional electric utilities for peaking power generation are evaluated. Conceptual designs of selected thermal energy storage systems integrated with conventional utilities are considered including characteristics of alternate systems for peaking power generation, viz gas turbines and coal fired cycling plants. Competitive benefit analysis of thermal energy storage systems with alternate systems for peaking power generation and recommendations for development and field test of thermal energy storage with a conventional utility are included. Results indicate that thermal energy storage is only marginally competitive with coal fired cycling power plants and gas turbines for peaking power generation.

  2. Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

    PubMed

    Kolpak, Alexie M; Grossman, Jeffrey C

    2011-08-10

    Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

  3. A novel application of concentrated solar thermal energy in foundries.

    PubMed

    Selvaraj, J; Harikesavan, V; Eshwanth, A

    2016-05-01

    Scrap preheating in foundries is a technology that saves melting energy, leading to economic and environmental benefits. The proposed method in this paper utilizes solar thermal energy for preheating scrap, effected through a parabolic trough concentrator that focuses sunlight onto a receiver which carries the metallic scrap. Scraps of various thicknesses were placed on the receiver to study the heat absorption by them. Experimental results revealed the pattern with which heat is gained by the scrap, the efficiency of the process and how it is affected as the scrap gains heat. The inferences from them gave practical guidelines on handling scraps for best possible energy savings. Based on the experiments conducted, preheat of up to 160 °C and a maximum efficiency of 70 % and a minimum efficiency of 40 % could be achieved across the time elapsed and heat gained by the scrap. Calculations show that this technology has the potential to save around 8 % of the energy consumption in foundries. Cumulative benefits are very encouraging: 180.45 million kWh of energy savings and 203,905 t of carbon emissions cut per year across the globe. This research reveals immense scope for this technology to be adopted by foundries throughout the world.

  4. Solar Energy System Performance Evaluation: seasonal report for Wormser, Columbia, South Carolina

    SciTech Connect

    1980-08-01

    The Wormser Solar Energy System located in a four unit townhouse apartment (5400 square feet) in Columbia, South Carolina was designed to provide 50% of the hot water and 70% of the space heating by the Wormser Scientific Corporation, Stamford, Connecticut. The Solar Energy System consists of 266 ft/sup 2/ of pyramidal optics, flat-plate liquid collectors, a solar window area of 1152 ft/sup 2/, a 2500 gallon thermal water storage tank, an energy transport system (water), heat exchangers, pumps, controls and four domestic hot water (DHW) tanks. Electrical elements in each domestic hot water tank provide necessary auxiliary energy for hot water. Four multifunctional heat pumps, supplied with solar heated water provide space heating energy to the apartments, collector freeze protection is provided through the location of the collectors inside the attic. The system with six modes of operation became oprational in February 1978. The following topics are discussed: system description, performance assessment, operating energy, energy savings, maintenance, summary and conclusions.

  5. Thermal energy storage for cooling of commercial buildings

    SciTech Connect

    Akbari, H. ); Mertol, A. )

    1988-07-01

    The storage of coolness'' has been in use in limited applications for more than a half century. Recently, because of high electricity costs during utilities' peak power periods, thermal storage for cooling has become a prime target for load management strategies. Systems with cool storage shift all or part of the electricity requirement from peak to off-peak hours to take advantage of reduced demand charges and/or off-peak rates. Thermal storage technology applies equally to industrial, commercial, and residential sectors. In the industrial sector, because of the lack of economic incentives and the custom design required for each application, the penetration of this technology has been limited to a few industries. The penetration rate in the residential sector has been also very limited due to the absence of economic incentives, sizing problems, and the lack of compact packaged systems. To date, the most promising applications of these systems, therefore, appear to be for commercial cooling. In this report, the current and potential use of thermal energy storage systems for cooling commercial buildings is investigated. In addition, a general overview of the technology is presented and the applicability and cost-effectiveness of this technology for developed and developing countries are discussed. 28 refs., 12 figs., 1 tab.

  6. Thermal energy storage for a space solar dynamic power system

    NASA Technical Reports Server (NTRS)

    Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.

    1985-01-01

    In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

  7. Thermal energy storage for the Stirling engine powered automobile

    NASA Technical Reports Server (NTRS)

    Morgan, D. T. (Editor)

    1979-01-01

    A thermal energy storage (TES) system developed for use with the Stirling engine as an automotive power system has gravimetric and volumetric storage densities which are competitive with electric battery storage systems, meets all operational requirements for a practical vehicle, and can be packaged in compact sized automobiles with minimum impact on passenger and freight volume. The TES/Stirling system is the only storage approach for direct use of combustion heat from fuel sources not suitable for direct transport and use on the vehicle. The particular concept described is also useful for a dual mode TES/liquid fuel system in which the TES (recharged from an external energy source) is used for short duration trips (approximately 10 miles or less) and liquid fuel carried on board the vehicle used for long duration trips. The dual mode approach offers the potential of 50 percent savings in the consumption of premium liquid fuels for automotive propulsion in the United States.

  8. Microwave impregnation of porous materials with thermal energy storage materials

    SciTech Connect

    Benson, D.K.; Burrows, R.W.

    1991-03-13

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent tc the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  9. Molten salt thermal energy storage for utility peaking loads

    NASA Technical Reports Server (NTRS)

    Ferrara, A.; Haslett, R.; Joyce, J.

    1977-01-01

    This paper considers the use of thermal energy storage (TES) in molten salts to increase the capacity of power plants. Five existing fossil and nuclear electric utility plants were selected as representative of current technology. A review of system load diagrams indicated that TES to meet loads over 95% of peak was a reasonable goal. Alternate TES heat exchanger locations were evaluated, showing that the stored energy should be used either for feedwater heating or to generate steam for an auxiliary power cycle. Specific salts for each concept are recommended. Design layouts were prepared for one plant, and it was shown that a TES tube/shell heat exchanger system could provide about 7% peaking capability at lower cost than adding steam generation capacity. Promising alternate heat exchanger concepts were also identified.

  10. Microwave impregnation of porous materials with thermal energy storage materials

    SciTech Connect

    Benson, D.K.; Burrows, R.W.

    1992-12-31

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  11. Preliminary considerations for extraction of thermal energy from magma

    SciTech Connect

    Hickox, C.E.; Dunn, J.C.

    1985-01-01

    Simplified mathematical models are developed to describe the extraction of thermal energy from magma based on the concept of a counterflow heat exchanger inserted into the magma body. Analytical solutions are used to investigate influence of the basic variables on electric power production. Calculations confirm that the proper heat exchanger flow path is down the annulus with hot fluid returning to the surface through the central core. The core must be insulated from the annulus to achieve acceptable wellhead temperatures, but this insulation thickness can be quite small. The insulation is effective in maintaining the colder annular flow below expected formation temperatures so that a net heat gain from the formation above a magma body is predicted. The analyses show that optimum flow rates exist that maximize electric power production. These optimum flow rates are functions of the heat transfer coefficients that describe magma energy extraction. 15 refs., 3 figs.

  12. OCEAN THERMAL ENERGY CONVERSION: AN OVERALL ENVIRONMENTAL ASSESSMENT

    SciTech Connect

    Sands, M. Dale

    1980-08-01

    Significant acccrmplishments in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power within this decade with subsequent large scale commercialization following by the turn of the century. Under U.S. Department of Energy funding, the Oceanic Engineering Operations of Interstate Electronics Corporation has prepared several OTEC Environmental Assessments over the past years, in particular, the OTEC Programmatic Environmental Assessment. The Programmatic EA considers several technological designs (open- and closed-cycle), plant configuratlons (land-based, moored, and plant-ship), and power usages (baseload electricity, ammonia and aluminum production). Potential environmental impacts, health and safetv issues and a status update of the institutional issues as they influence OTEC deployments, are included.

  13. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, David K.; Burrows, Richard W.

    1993-01-01

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  14. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, D.K.; Burrows, R.W.

    1993-04-13

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  15. Seasonal variation in thermal tolerance, oxygen consumption, antioxidative enzymes and non-specific immune indices of Indian hill trout, Barilius bendelisis (Hamilton, 1807) from central Himalaya, India.

    PubMed

    Sharma, Neeraj Kumar; Akhtar, M S; Pandey, Nityanand; Singh, Ravindra; Singh, Atul Kumar

    2015-08-01

    We studied the season dependent thermal tolerance, oxygen consumption, respiratory burst response and antioxidative enzyme activities in juveniles of Barilius bendelisis. The critical thermal maximum (CTmax), lethal thermal maximum (LTmax), critical thermal minimum (CTmin) and lethal thermal minimum (LTmin) were significantly different at five different seasons viz. winter (10.64°C), spring (16.25°C), summer (22.11°C), rainy (20.87°C) and autumn (17.77°C). The highest CTmax was registered in summer (36.02°C), and lowest CTmin was recorded during winter (2.77°C). Water temperature, dissolved oxygen and pH were strongly related to CTmax, LTmax, CTmin and LTmin suggesting seasonal acclimatization of B. bendelisis. The thermal tolerance polygon area of the B. bendelisis juveniles within the range of seasonal temperature (10.64-22.11°C) was calculated as 470.92°C(2). Oxygen consumption rate was significantly different (p<0.05) between seasons with maximum value during summer (57.66mgO2/kg/h) and lowest in winter (32.60mgO2/kg/h). Total white blood cell count including neutrophil and monocytes also showed significant difference (p<0.05) between seasons with maximum value during summer and minimum number in winter and were found correlated to temperature, dissolved oxygen, pH and respiratory burst activity. Respiratory burst activity of blood phagocytes significantly differed (p<0.05) among seasons with higher value during summer (0.163 OD540nm) and minimum in winter season (0.054 OD540nm). The activity of superoxide dismutase, catalase and glutathione-s-transferase both in liver and gill, also varied significantly (p<0.05) during different seasons. Overall results of this study suggest that multiple environmental factors play a role in seasonal acclimation in B. bendelisis, which modulate the thermal tolerance, oxygen consumption, respiratory burst activity and status of anti-oxidative potential in wild environment.

  16. [Feeding of two amphibian species (Anura: Hylidae) during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina].

    PubMed

    Antoniazzi, Carolina Elizabet; López, Javier Alejandro; Duré, Marta; Falico, Diego Alejandro

    2013-06-01

    Feeding of two amphibian species (Anura: Hylidae) during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina. In environments with thermal and pluvial seasonality such as those of the Middle Paraná River floodplain (Province of Santa Fe, Argentina), most amphibian species reproduce during the warm season and drastically diminish their activity during winter. Even though, a few species remain active during the cold season, such as Hypsiboas pulchellus that has its reproductive peak during the autumn-winter period (and the consequent energy demand). The objective of this study was to analyze and compare the feeding and development of fat bodies during the low temperature season for H. pulchellus and Dendropsophus nanus. We analyzed entire gastrointestinal tract contents of both species (H. pulchellus = 110 specimens; D. nanus = 114 specimens) and applied an index (IRI%) that combines prey abundance, volume and frequency to describe frogs diets; we used fat bodies weights as indicators of stored energy reserves. We compared diet between species with a niche overlap index (Ojk: 0-1) and used null models to ascribe statistical significance to evaluate overlap; and we analyzed variation in empty guts proportions through months and between species. Also, using ANCOVAs we explored differences in fat bodies, number and volume of prey consumed along months, between species and sexes. The most important preys in H. pulchellus diet during the cold season were Araneae (IRI% = 34.96), Chironomidae (IRI% = 33.08), Tipulidae (IRI% = 11.44) and Gryllidae (IR1% = 7.31); while for D. nanus, Chironomidae (IR1% = 48.14), Tipulidae (IRI% = 18.41), Psychodidae (IRI% = 7.44) and Araneae (IRI% = 7.34). Diet overlap between species was elevated (Ojk=0.78) and higher than expected by chance (mean simulated indices: Ojk = 0.04; p[observed > or = expected]<0.01; p[observed < or = expected] = 1). In H. pulchellus there was a monthly variation in number

  17. Simulation of diurnal thermal energy storage systems: Preliminary results

    NASA Astrophysics Data System (ADS)

    Katipamula, S.; Somasundaram, S.; Williams, H. R.

    1994-12-01

    This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system; and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

  18. Designing energy dissipation properties via thermal spray coatings

    DOE PAGES

    Brake, Matthew R. W.; Hall, Aaron Christopher; Madison, Jonathan D.

    2016-12-14

    The coefficient of restitution is a measure of energy dissipation in a system across impact events. Often, the dissipative qualities of a pair of impacting components are neglected during the design phase. This research looks at the effect of applying a thin layer of metallic coating, using thermal spray technologies, to significantly alter the dissipative properties of a system. We studied the dissipative properties across multiple impacts in order to assess the effects of work hardening, the change in microstructure, and the change in surface topography. The results of the experiments indicate that any work hardening-like effects are likely attributablemore » to the crushing of asperities, and the permanent changes in the dissipative properties of the system, as measured by the coefficient of restitution, are attributable to the microstructure formed by the thermal spray coating. Furthermore, the microstructure appears to be robust across impact events of moderate energy levels, exhibiting negligible changes across multiple impact events.« less

  19. Study on Tetradecane Nanoemulsion for Thermal Energy Transportation and Storage

    NASA Astrophysics Data System (ADS)

    Fumoto, Koji; Kawaji, Masahiro; Kawanami, Tsuyoshi

    Phase change emulsion (PCE) is a novel fluid used for heat storage and transfer. It has the following characteristics: higher apparent specific heat and higher heat transfer ability in the phase-change temperature range as compared to the conventional single-phase heat transfer fluids. In particular, oil-in-water (O/W) emulsions are latent heat storage materials that have low melting points, thus offering attractive opportunities for heat transfer enhancement and thermal energy transportation and storage. In this paper, milky white oil-in-water emulsions have been formed using water, Tween 80, Span 80, and tetradecane by low-energy emulsification methods (e.g., the phase inversion temperature (PIT) method). The relations between the component ratios of the emulsions and both the particle diameters and the stability of the resulting emulsions have been determined by dynamic light scattering (DLS) and vibration viscometry. The results show that the apparent viscosity of the nanoemulsion is lower than that of an emulsion, which was prepared with the same mixing ratio of surfactant and concentration of phase change material. Moreover, the surfactant concentration is found to contribute to the stability of the phase change nanoemulsion. Results indicate that the phase change nanoemulsion is a promising material for thermal storage applications.

  20. Transition of surface energy budget in the Gobi Desert between spring and summer seasons

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Reiter, Elmar R.; Gao, Youxi

    1986-01-01

    The surface energetics of the southwest Gobi Desert, including the temporal variations and diurnally averaged properties of the surface energy budget components, was investigated. The field program was conducted during the spring and summer of 1984, with the measurement system designed to monitor radiative exchange, heat/moisture storage in the soil, and sensible and latent heat exhange between the ground and the atmosphere. Results of the analysis reveal a seasonal transition feature not expected of a midlatitude desert. Namely, the differences in both surface radiation exchange and the distibution of sensible and latent heat transfer arise within a radiatively forced environment that barely deviates from spring to summer in terms of available solar energy at the surface. Both similarities and differences in the spring and summer surface energy budgets arise from differences imparted to the system by an increase in the summertime atmospheric moisture content. Changes in the near-surface mixing ratio are shown to alter the effectiveness of the desert surface in absorbing radiative energy and redistibuting it to the lower atmosphere through sensible and latent heat exchange.

  1. Utilizing Ocean Thermal Energy in a Submarine Robot

    NASA Technical Reports Server (NTRS)

    Jones, Jack; Chao, Yi

    2009-01-01

    A proposed system would exploit the ocean thermal gradient for recharging the batteries in a battery-powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and depths, measuring temperature and salinity. The proposed system is related to, but not the same as, previously reported ocean thermal energy conversion (OTEC) systems that exploit the ocean thermal gradient but consist of stationary apparatuses that span large depth ranges. The system would include a turbine driven by working fluid subjected to a thermodynamic cycle. CO2 has been provisionally chosen as the working fluid because it has the requisite physical properties for use in the range of temperatures expected to be encountered in operation, is not flammable, and is much less toxic than are many other commercially available refrigerant fluids. The system would be housed in a pressurized central compartment in a UUV equipped with a double hull (see figure). The thermodynamic cycle would begin when the UUV was at maximum depth, where some of the CO2 would condense and be stored, at relatively low temperature and pressure, in the annular volume between the inner and outer hulls. The cycle would resume once the UUV had ascended to near the surface, where the ocean temperature is typically greater than or equals 20 C. At this temperature, the CO2 previously stored at depth in the annular volume between the inner and outer hulls would be pressurized to approx. equals 57 bar (5.7 MPa). The pressurized gaseous CO2 would flow through a check valve into a bladder inside the pressurized compartment, thereby storing energy of the relatively warm, pressurized CO2 for subsequent use after the next descent to maximum depth.

  2. PHASE CHANGE MATERIALS IN FLOOR TILES FOR THERMAL ENERGY STORAGE

    SciTech Connect

    Douglas C. Hittle

    2002-10-01

    Passive solar systems integrated into residential structures significantly reduce heating energy consumption. Taking advantage of latent heat storage has further increased energy savings. This is accomplished by the incorporation of phase change materials into building materials used in passive applications. Trombe walls, ceilings and floors can all be enhanced with phase change materials. Increasing the thermal storage of floor tile by the addition of encapsulated paraffin wax is the proposed topic of research. Latent heat storage of a phase change material (PCM) is obtained during a change in phase. Typical materials use the latent heat released when the material changes from a liquid to a solid. Paraffin wax and salt hydrates are examples of such materials. Other PCMs that have been recently investigated undergo a phase transition from one solid form to another. During this process they will release heat. These are known as solid-state phase change materials. All have large latent heats, which makes them ideal for passive solar applications. Easy incorporation into various building materials is must for these materials. This proposal will address the advantages and disadvantages of using these materials in floor tile. Prototype tile will be made from a mixture of quartz, binder and phase change material. The thermal and structural properties of the prototype tiles will be tested fully. It is expected that with the addition of the phase change material the structural properties will be compromised to some extent. The ratio of phase change material in the tile will have to be varied to determine the best mixture to provide significant thermal storage, while maintaining structural properties that meet the industry standards for floor tile.

  3. Seasonal and clonal variations in technological and thermal properties of raw Hevea natural rubber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was undertaken over a ten-month period, under the environmental conditions within the state of Mato Grosso, Brazil, to evaluate the causes of variation in technological and thermal properties of raw natural rubber from different clones of Hevea brasiliensis (GT 1, PR 255, FX 3864 and RRIM...

  4. Efficient Solar-Thermal Energy Harvest Driven by Interfacial Plasmonic Heating-Assisted Evaporation.

    PubMed

    Chang, Chao; Yang, Chao; Liu, Yanming; Tao, Peng; Song, Chengyi; Shang, Wen; Wu, Jianbo; Deng, Tao

    2016-09-07

    The plasmonic heating effect of noble nanoparticles has recently received tremendous attention for various important applications. Herein, we report the utilization of interfacial plasmonic heating-assisted evaporation for efficient and facile solar-thermal energy harvest. An airlaid paper-supported gold nanoparticle thin film was placed at the thermal energy conversion region within a sealed chamber to convert solar energy into thermal energy. The generated thermal energy instantly vaporizes the water underneath into hot vapors that quickly diffuse to the thermal energy release region of the chamber to condense into liquids and release the collected thermal energy. The condensed water automatically flows back to the thermal energy conversion region under the capillary force from the hydrophilic copper mesh. Such an approach simultaneously realizes efficient solar-to-thermal energy conversion and rapid transportation of converted thermal energy to target application terminals. Compared to conventional external photothermal conversion design, the solar-thermal harvesting device driven by the internal plasmonic heating effect has reduced the overall thermal resistance by more than 50% and has demonstrated more than 25% improvement of solar water heating efficiency.

  5. The seasonal water and energy exchange above and within a boreal aspen forest

    NASA Astrophysics Data System (ADS)

    Blanken, P. D.; Black, T. A.; Neumann, H. H.; den Hartog, G.; Yang, P. C.; Nesic, Z.; Lee, X.

    2001-05-01

    The seasonal water and energy exchange of a boreal aspen forest underlain by a hazelnut understory is described. Measurements of above-aspen latent and sensible heat, short-wave and net radiation, and photosynthetically active radiation are compared to those measured above the hazelnut understory. Understory radiation measurements were made using a tram system. Energy storage at each measurement height was determined, and measurements of the soil moisture, temperature, and heat flux were made using an array of probes. The mean annual air temperature and total precipitation during 1994 were 1.2°C and 488.4 mm, respectively, above the 1951-1980 average -0.2°C and total 462.6 mm. There was a pronounced seasonal development of leaves, with the maximum leaf area index of the hazelnut (3.3 m 2 m -2) exceeding that of the aspen (2.3 m 2 m -2). Beneath-aspen radiation decreased exponentially as the aspen leaf area increased, and the calculated effective extinction coefficients decreased as the plant area index increased. At full aspen leaf, 27, 23, and 20% of the above-aspen short-wave, net, and photosynthetically active radiation, respectively, reached the hazelnut. The diurnal energy balance at both heights showed pronounced seasonal trends. Sensible heat from the forest floor dominated during the leaf-free period, whereas latent heat from the overstory dominated during the leafed period. The fraction of the annual precipitation evaporated was 82-91%, with 67-68%, 26-28%, and 4-7% originating from the aspen, hazelnut, and soil, respectively. Over the leafed period, soil water was depleted from the root zone (0-60 cm depth) and accumulated between the 61-123 cm depth, overall resulting in a deficit of 34.7 mm between 0-123 cm depths. This soil water balance compared well with the daily integrated difference between precipitation and eddy-covariance determined measurements of evaporation.

  6. Review of simulation techniques for aquifer thermal energy storage (ATES)

    SciTech Connect

    Mercer, J.W.; Faust, C.R.; Miller, W.J.; Pearson, F.J. Jr.

    1981-03-01

    The storage of thermal energy in aquifers has recently received considerable attention as a means to conserve and more efficiently use energy supplies. The analysis of aquifer thermal energy storage (ATES) systems will rely on the results from mathematical and geochemical models. Therefore, the state-of-the-art models relevant to ATES was reviewed and evaluated. These models describe important processes active in ATES including ground-water flow, heat transport (heat flow), solute transport (movement of contaminants), and geochemical reactions. In general, available models of the saturated ground-water environment are adequate to address most concerns associated with ATES; that is, design, operation, and environmental assessment. In those cases where models are not adequate, development should be preceded by efforts to identify significant physical phenomena and relate model parameters to measurable quantities. Model development can then proceed with the expectation of an adequate data base existing for the model's eventual use. Review of model applications to ATES shows that the major emphasis has been on generic sensitivity analysis and site characterization. Assuming that models are applied appropriately, the primary limitation on model calculations is the data base used to construct the model. Numerical transport models are limited by the uncertainty of subsurface data and the lack of long-term historical data for calibration. Geochemical models are limited by the lack of thermodynamic data for the temperature ranges applicable to ATES. Model applications undertaken with data collection activities on ATES sites should provide the most important contributions to the understanding and utilization of ATES. Therefore, the primary conclusion of this review is that model application to field sites in conjunction with data collection activities is essential to the development of this technology.

  7. Vacuum thermal cycle life testing of high temperature thermal energy storage

    NASA Astrophysics Data System (ADS)

    Ponnappan, Rengasamy; Beam, Jerry E.

    1991-01-01

    An experimental program to investigate the corrosion compatibility of the high temperature thermal energy storage (TES) salts with Inconel-617 container was initiated at the Thermal Laboratory of the Wright Research and Development Center (WRDC) in 1985. Three fluoride eutectic mixtures: LiF-MgF2-KF, LiF-MgF2-NaF, and LiF-MgF2 having melting points in the neighborhood of 1000 K and heats of fusion above 750 kJ/kg were chosen. High purity analytical grade component salts were processed in oxygen and moisture-free inert atmosphere, and melted in situ in the Inconel-617 containers. The containers were sealed by electron beam-welding of the end caps thereby evacuating the void volume. The TES capsules thus formed were placed in a tubular vacuum furnace for continuous thermal cycle life testing by cycling them ±100 K from the eutectic temperature every 2 hours. The capsules have successfully undergone 40,000 hours and 10,000 cycles of testing as of April 1990 and continuing on the test. This is believed to be the longest record available on the TES corrosion compatibility data. The present results clearly indicate that careful processing and proper welding are key factors in obtaining a longlife TES salt-containment system.

  8. A system for measuring thermal activation energy levels in silicon by thermally stimulated capacitance

    NASA Technical Reports Server (NTRS)

    Cockrum, R. H.

    1982-01-01

    One method being used to determine energy level(s) and electrical activity of impurities in silicon is described. The method is called capacitance transient spectroscopy (CTS). It can be classified into three basic categories: the thermally stimulated capacitance method, the voltage-stimulated capacitance method, and the light-stimulated capacitance method; the first two categories are discussed. From the total change in capacitance and the time constant of the capacitance response, emission rates, energy levels, and trap concentrations can be determined. A major advantage of using CTS is its ability to detect the presence of electrically active impurities that are invisible to other techniques, such as Zeeman effect atomic absorption, and the ability to detect more than one electrically active impurity in a sample. Examples of detection of majority and minority carrier traps from gold donor and acceptor centers in silicon using the capacitance transient spectrometer are given to illustrate the method and its sensitivity.

  9. Seasonal ecology and thermal constraints of Telenomus spp. (Hymenoptera: Scelionidae), egg parasitoids of the hemlock looper (Lepidoptera: Geometridae).

    PubMed

    Legault, Simon; Hébert, Christian; Blais, Julie; Berthiaume, Richard; Bauce, Eric; Brodeur, Jacques

    2012-12-01

    We describe seasonal patterns of parasitism by Telenomus coloradensis Crawford, Telenomus droozi Muesebeck, Telenomus flavotibiae Pelletier (Hymenoptera: Scelionidae), and Trichogramma spp. (Hymenoptera: Trichogrammatidae), egg parasitoids of the hemlock looper, Lambdina fiscellaria (Guenée) (Lepidoptera: Geometridae), after a 3-yr survey of defoliated stands in the lower St. Lawrence region (Quebec, Canada). Results from sentinel trap sampling indicate that T. coloradensis and T. droozi are the most common species, whereas parasitism by T. flavotibiae and Trichogramma spp. is rare. Telenomus coloradensis and T. droozi show similar seasonal periods of parasitism, both species being active in early spring (late April) at temperatures as low as 4°C. Using thermal threshold (T(0)) and thermal constant (K) for immature development of T. coloradensis males and females from egg to adult emergence, we estimated that the spring progeny emerges in the middle of the summer while hemlock looper eggs are absent from the forest environment. Parasitoid females would then mate and remain in the environment to 1) exploit alternate host species, 2) enter into quiescence and later parasitize eggs laid by hemlock looper females in the fall, 3) enter into a reproductive diapause and parasitize hemlock looper eggs only the next spring, or all of these. Although previous studies have shown that T. coloradensis can overwinter in its immature form within the host egg, our field and laboratory results indicate that in the lower St. Lawrence region, this species principally enters diapause as fertilized females, with a mean supercooling point of -30.6°C in the fall.

  10. Seasonal Variations in the CO Line Profile and the Retrieved Thermal/Pressure Structures in the Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Khayat, Alain; Villanueva, G. L.; Mumma, M. J.; Riesen, T. E.; Tokunaga, A. T.

    2013-10-01

    We report retrievals of temperature vertical profiles up to 100 km over Tharsis and Syrtis regions on Mars obtained by inverting the strong rotational (3-2) line of carbon monoxide (CO) at 346 GHz. Observations of CO were made from mid Northern Spring to early Northern Summer on Mars (Ls= 36°-108°, 23 Nov, 2011 - 13 May, 2012) using the Caltech Submillimeter Observatory's (CSO) high-resolution heterodyne receiver (Barney) on top of Mauna Kea, Hawai'i. The temperature profiles were derived using our radiative transfer model that considers the latest spectroscopic constants for CO collisionally broadened by CO2. We observe notable changes of the line profile for different dates, which are directly related to seasonal variations in the thermal/pressure structure of the atmosphere. The seasonal variability of the martian CO line profile, the extracted temperature profiles, and comparisons with modeled profiles from the Mars Climate Database (Lewis et al, 1999) will be presented. We gratefully acknowledge support from the NASA Planetary Astronomy Program , NASA Astrobiology Institute, Planetary Atmospheres programs. This material is based upon work at the Caltech Submillimeter Observatory, which is operated by the California Institute of Technology under cooperative agreement with the National Science Foundation, grant number AST-0838261.

  11. A numerical study of gyres, thermal fronts and seasonal circulation in austral semi-enclosed gulfs

    NASA Astrophysics Data System (ADS)

    Tonini, Mariano H.; Palma, Elbio D.; Piola, Alberto R.

    2013-08-01

    This article analyses the results from a high resolution numerical model of the North Patagonian Gulfs (San Matías Gulf, SMG; Nuevo Gulf, NG; and San José Gulf, SJG), a region of the South Western Atlantic Shelf that has long been recognized for its high productivity and biodiversity. The aim of the study is to explore the physical processes that control the mean circulation and its seasonal variability with focus on the generation of recirculation features (gyres) and frontal structures. The numerical results showed that both tidal and wind forcing significantly contribute to delineate the frontal structures and the seasonal circulation in the North Patagonian Gulfs. The overall summer circulation pattern in SMG is dominated by two strong cyclonic subgyres in the northern and southern sectors while NG showed only one gulf-wide cyclonic gyre. The northern subgyre in SMG and the NG gyre are caused by the interaction of the tides and the evolving stratification driven by surface heat and freshwater fluxes. A series of sensitivity experiments showed that the formation and intensity of a summer zonal front in SMG is controlled by the wind-driven advection of cold waters from a homogenized pool generated by intense tidal mixing in the inner continental shelf (east of Valdés Península). From April to August, when winter erodes the stratification, the northern SMG subgyre and the NG gyre spin down and gradually shrink in size. At this time of the year, the western SMG and NG are occupied by an anticyclonic gyre driven by intense westerlies. In contrast, the mean circulation in SJG is dominated year-round by a pair of strong counter-rotating eddies produced by tidal rectification.

  12. Simulated thermal energy demand and actual energy consumption in refurbished and non-refurbished buildings

    NASA Astrophysics Data System (ADS)

    Ilie, C. A.; Visa, I.; Duta, A.

    2016-08-01

    The EU legal frame imposes the Nearly Zero Energy Buildings (nZEB) status to any new public building starting with January 1st, 2019 and for any other new building starting with 2021. Basically, nZEB represents a Low Energy Building (LEB) that covers more than half of the energy demand by using renewable energy systems installed on or close to it. Thus, two steps have to be followed in developing nZEB: (1) reaching the LEB status through state- of-the art architectural and construction solutions (for the new buildings) or through refurbishing for the already existent buildings, followed by (2) implementing renewables; in Romania, over 65% of the energy demand in a building is directly linked to heating, domestic hot water (DHW), and - in certain areas - for cooling. Thus, effort should be directed to reduce the thermal energy demand to be further covered by using clean and affordable systems: solar- thermal systems, heat pumps, biomass, etc. or their hybrid combinations. Obviously this demand is influenced by the onsite climatic profile and by the building performance. An almost worst case scenario is approached in the paper, considering a community implemented in a mountain area, with cold and long winters and mild summers (Odorheiul Secuiesc city, Harghita county, Romania). Three representative types of buildings are analysed: multi-family households (in blocks of flats), single-family houses and administrative buildings. For the first two types, old and refurbished buildings were comparatively discussed.

  13. Technical use of solar energy: Conversion from solar to thermal energy, solar cooling and thermal energy storage

    NASA Astrophysics Data System (ADS)

    Arafa, A.; Fisch, N.; Hahne, E.; Kraus, K.; Seemann, D.; Seifert, B.; Sohns, J.; Schetter, G.; Schweigerer, W.

    1983-12-01

    Experimental and theoretical studies in the field of solar energy utilization are reviewed. Specific topics considered are: flat plate water collectors, solar absorbers, air collectors, solar absorption cooling, solar simulators, aquifiers, latent heat stores, and space heating systems.

  14. Expected benefits of federally-funded thermal energy storage research

    NASA Astrophysics Data System (ADS)

    Spanner, G. E.; Daellenbach, K. K.; Hughes, K. R.; Brown, D. R.; Drost, M. K.

    1992-09-01

    Pacific Northwest Laboratory (PNL) conducted this study for the Office of Advanced Utility Concepts of the US Department of Energy (DOE). The objective of this study was to develop a series of graphs that depict the long-term benefits of continuing DOE's thermal energy storage (TES) research program in four sectors: building heating, building cooling, utility power production, and transportation. The study was conducted in three steps. The first step was to assess the maximum possible benefits technically achievable in each sector. In some sectors, the maximum benefit was determined by a 'supply side' limitation, and in other sectors, the maximum benefit is determined by a 'demand side' limitation. The second step was to apply economic cost and diffusion models to estimate the benefits that are likely to be achieved by TES under two scenarios: (1) with continuing DOE funding of TES research; and (2) without continued funding. The models all cover the 20-year period from 1990 to 2010. The third step was to prepare graphs that show the maximum technical benefits achievable, the estimated benefits with TES research funding, and the estimated benefits in the absence of TES research funding. The benefits of federally-funded TES research are largely in four areas: displacement of primary energy, displacement of oil and natural gas, reduction in peak electric loads, and emissions reductions.

  15. Expected benefits of federally-funded thermal energy storage research

    SciTech Connect

    Spanner, G E; Daellenbach, K K; Hughes, K R; Brown, D R; Drost, M K

    1992-09-01

    Pacific Northwest Laboratory (PNL) conducted this study for the Office of Advanced Utility Concepts of the US Department of Energy (DOE). The objective of this study was to develop a series of graphs that depict the long-term benefits of continuing DOE's thermal energy storage (TES) research program in four sectors: building heating, building cooling, utility power production, and transportation. The study was conducted in three steps- The first step was to assess the maximum possible benefits technically achievable in each sector. In some sectors, the maximum benefit was determined by a supply side'' limitation, and in other sectors, the maximum benefit is determined by a demand side'' limitation. The second step was to apply economic cost and diffusion models to estimate the benefits that are likely to be achieved by TES under two scenarios: (1) with continuing DOE funding of TES research, and (2) without continued funding. The models all cover the 20-year period from 1990 to 2010. The third step was to prepare graphs that show the maximum technical benefits achievable, the estimated benefits with TES research funding, and the estimated benefits in the absence of TES research funding. The benefits of federally-funded TES research are largely in four areas: displacement of primary energy, displacement of oil and natural gas, reduction in peak electric loads, and emissions reductions.

  16. Expected benefits of federally-funded thermal energy storage research

    SciTech Connect

    Spanner, G.E.; Daellenbach, K.K.; Hughes, K.R.; Brown, D.R.; Drost, M.K.

    1992-09-01

    Pacific Northwest Laboratory (PNL) conducted this study for the Office of Advanced Utility Concepts of the US Department of Energy (DOE). The objective of this study was to develop a series of graphs that depict the long-term benefits of continuing DOE`s thermal energy storage (TES) research program in four sectors: building heating, building cooling, utility power production, and transportation. The study was conducted in three steps- The first step was to assess the maximum possible benefits technically achievable in each sector. In some sectors, the maximum benefit was determined by a ``supply side`` limitation, and in other sectors, the maximum benefit is determined by a ``demand side`` limitation. The second step was to apply economic cost and diffusion models to estimate the benefits that are likely to be achieved by TES under two scenarios: (1) with continuing DOE funding of TES research, and (2) without continued funding. The models all cover the 20-year period from 1990 to 2010. The third step was to prepare graphs that show the maximum technical benefits achievable, the estimated benefits with TES research funding, and the estimated benefits in the absence of TES research funding. The benefits of federally-funded TES research are largely in four areas: displacement of primary energy, displacement of oil and natural gas, reduction in peak electric loads, and emissions reductions.

  17. Waterborne noise due to ocean thermal energy conversion plants

    SciTech Connect

    Janota, C.P.; Thompson, D.E.

    1983-07-01

    Public law reflects a United States national commitment to the rapid development of Ocean Thermal Energy Conversion (OTEC) as an alternate energy source. OTEC plants extract the stored solar energy from the world's tropical seas and in so doing pose a potential for altering the character of the ambient noise there. The sources of noise from an OTEC plant are analyzed in the context of four configurations, two of which were built and tested, and two which are concepts for future full-scale moored facilities. The analysis indicates that the noise resulting from the interaction of turbulence with the seawater pumps is expected to dominate in the frequency range 10 Hz to 1 kHz. Measured radiated noise data from the OTEC-I research plant, located near the island of Hawaii, are compared with the analysis. The measured data diverge from the predicted levels at frequencies above about 60 Hz because of dominant non-OTEC noise sources on this platform. However, at low frequency, the measured broadband noise is comparable to that predicted.

  18. Thermal energy storage systems using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Weast, T.; Shannon, L.

    1980-01-01

    A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

  19. Solar energy system performance evaluation: seasonal report for IBM System 4 at Clinton, Mississippi

    SciTech Connect

    1980-07-01

    The IBM System 4 Solar Energy System was designed to provide 35 percent of the space heating and 62 percent of the domestic hot water (DHW) preheating for a single-family residence located within the United States. The system is a prepackaged unit called the Remote Solar Assembly which has been integrated into the heating and DHW system in a dormitory in Clinton, Mississippi. The system consists of 259 square feet of Solaron 2001 Series flat-plate-air collectors, a rock thermal storage containing 5 1/2 ton of rock, heat exchangers, blowers, a 52 gallon preheat tank, controls, and associated plumbing, two 30 gallon electric water heaters draw water from the preheat tank. A 20 kilowatt, duct mounted, electric heater supplies auxiliary energy. This system which has three modes of system operation was activated September, 1978. A system performance assessment is presented.

  20. Solar energy system performance evaluation: Seasonal report for Contemporary-Manchester, Manchester, New Hampshire

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The operational and thermal performance of the solar energy system, Contemporary-Manchester, is described. The system was designed by Contemporary Systems Incorporated to provide space heating and domestic hot water preheating for a three story dwelling located on the New Hampshire Vocational Technical College campus, Manchester, New Hampshire. The net fossil energy savings for the period from March, 1979 to February, 1980 was 14.52 million Btu. However, the performance of the system must be degraded due to the fact that the building was unoccupied throughout the data assessment and analysis period. The unoccupied status prevented the normal adjustment of heating and ventilating controls for maintenance of comfort levels within the building. This lack of occupancy also prevented the typical family hot water usage, which would have allowed for more realistic evaluation of the hot water subsystem.

  1. Thermal Comfort Project: A Cool Solution to the Nation's Energy Security Challenges

    SciTech Connect

    Not Available

    2002-05-01

    This fact sheet describes how the CTTS thermal comfort project will increase energy security by reducing fuel consumed by auxiliary loads such as air conditioning. It also describes physiological and psychological computer models and thermal comfort manikin.

  2. Impacts of convection on high-temperature aquifer thermal energy storage

    NASA Astrophysics Data System (ADS)

    Beyer, Christof; Hintze, Meike; Bauer, Sebastian

    2016-04-01

    Seasonal subsurface heat storage is increasingly used in order to overcome the temporal disparities between heat production from renewable sources like solar thermal installations or from industrial surplus heat and the heat demand for building climatisation or hot water supply. In this context, high-temperature aquifer thermal energy storage (ATES) is a technology to efficiently store and retrieve large amounts of heat using groundwater wells in an aquifer to inject or withdraw hot or cold water. Depending on the local hydrogeology and temperature amplitudes during high-temperature ATES, density differences between the injected hot water and the ambient groundwater may induce significant convective flow components in the groundwater flow field. As a consequence, stored heat may accumulate at the top of the storage aquifer which reduces the heat recovery efficiency of the ATES system. Also, an accumulation of heat at the aquifer top will induce increased emissions of heat to overlying formations with potential impacts on groundwater quality outside of the storage. This work investigates the impacts of convective heat transport on the storage efficiency of a hypothetical high-temperature ATES system for seasonal heat storage as well as heat emissions to neighboring formations by numerical scenario simulations. The coupled groundwater flow and heat transport code OpenGeoSys is used to simulate a medium scale ATES system operating in a sandy aquifer of 20 m thickness with an average groundwater temperature of 10°C and confining aquicludes at top and bottom. Seasonal heat storage by a well doublet (i.e. one fully screened "hot" and "cold" well, respectively) is simulated over a period of 10 years with biannual injection / withdrawal cycles at pumping rates of 15 m³/h and for different scenarios of the temperature of the injected water (20, 35, 60 and 90 °C). Simulation results show, that for the simulated system significant convective heat transport sets in when

  3. Wollastonite hybridizing stearic acid as thermal energy storage material

    NASA Astrophysics Data System (ADS)

    Xu, Dawei; Yang, Huaming

    2014-11-01

    This paper reported on the preparation of a novel stearic acid (SA)/wollastonite (W) composite as a form-stable phase change material (PCM) for thermal energy-storage (TES) by vacuum impregnation, and especially investigated the effect of the size grade of W on the thermal properties of the SA/W composite. Samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle-size analysis, and differential scanning calorimetry (DSC). Natural W (Wr) was classified into four size grades by wet screening. The results indicate that no chemical reaction took place between SA and W, and the SA load in the SA/W composite increased with an increase in the length/diameter (L/D) ratio of the W. The SA/W composite with a W L/D ratio of 22.5 exhibited latent heats of melting and freezing of 58.64 J/g and 56.95 J/g, respectively, which was higher than those of the composite incorporating natural W. We believe that the as-prepared form-stable PCM composite could provide a potential means of TES for the concentrated solar power.

  4. PCM-impregnated polymer microcomposites for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Stark, Philip

    1990-07-01

    The encapsulation of phase change materials (PCMs) into the micropores of an ordered polymer film was investigated. Paraffin wax and high density polyethylene wax were infiltrated successfully into extruded films of the ordered polymer PBZT by a solvent exchange technique to yield microcomposites with PCM levels on the order of 40 volume percent. These microcomposite films exhibit excellent mechanical stability under cyclic freeze-thaw conditions. However, their thermal energy storage capacities, as characterized by differential scanning calorimetry, decrease significantly following freeze-thaw cycling. It appears that the ultrastructure of the PBZT and the thinness of the film (which results in high cooling rates during freeze-thaw cycling) promote the retention of the amorphous form of the PCM rather than the crystalline form. Since the amorphous form of the PCM does not contribute to the latent heat of fusion, the heat storage capacity of the microcomposite is reduced.

  5. Control and performance of a photovoltaic-thermal energy system

    NASA Astrophysics Data System (ADS)

    Bazques, E. O.

    1983-12-01

    The control of a photovoltaic/thermal energy (PV/T) system in general and optimization of performance in particular through use of modern (state space) control methods, stochastic weather inputs, and second law of thermodynamics analysis is addressed. Significant improvement in system performance is noted using optimal control when compared to conventional on/off, multilevel, or proportional controllers for deterministic weather forcing functions. Optimal system control, analyzed first through use of Pontryagin's Minimum Principle and then implemented by specification of a quadratic performance index and solution of matrix Riccati equations, is shown to be a viable and useful strategy for these hybrid systems. Stochastic weather techniques which incorporate temperature/insolation probability density matrices and least square constants are found to be a valid method for reducing simulation requirements as long as weather persistence effects are taken into account through use of information derived from Markov transition matrices.

  6. Extended development of a sodium hydroxide thermal energy storage module

    NASA Technical Reports Server (NTRS)

    Rice, R. E.; Rowny, P. E.; Cohen, B. M.

    1980-01-01

    The post-test evaluation of a single heat exchanger sodium hydroxide thermal energy storage module for use in solar electric generation is reported. Chemical analyses of the storage medium used in the experimental model are presented. The experimental verification of the module performance using an alternate heat transfer fluid, Caloria HT-43, is described. Based on these results, a design analysis of a dual heat exchanger concept within the storage module is presented. A computer model and a reference design for the dual system (storage working fluid/power cycle working fluid) were completed. The dual system is estimated to have a capital cost of approximately one half that of the single heat exchanger concept.

  7. Flight experiment of thermal energy storage. [for spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Namkoong, David

    1989-01-01

    Thermal energy storage (TES) enables a solar dynamic system to deliver constant electric power through periods of sun and shade. Brayton and Stirling power systems under current considerations for missions in the near future require working fluid temperatures in the 1100 to 1300+ K range. TES materials that meet these requirements fall into the fluoride family of salts. Salts shrink as they solidify, a change reaching 30 percent for some salts. Hot spots can develop in the TES container or the container can become distorted if the melting salt cannot expand elsewhere. Analysis of the transient, two-phase phenomenon is being incorporated into a three-dimensional computer code. The objective of the flight program is to verify the predictions of the code, particularly of the void location and its effect on containment temperature. The four experimental packages comprising the program will be the first tests of melting and freezing conducted under microgravity.

  8. Device and method for converting wood into thermal energy

    SciTech Connect

    Lynch, R.A.

    1983-01-18

    A device and method for burning wood for the purpose of heat generation is disclosed. The device has a flat grate on which the fuel is placed and a vertical combustion air inlet passage which discharges the air as a wide, flat ribbon at one end of the combustion chamber substantially at the top surface of the grate. Combustion is confined to a zone which progressively moves along the grate away from the air unit. The combustion gases are collected at the top of the combustion chamber which is arched and arranged to cause them to spiral and while still in the combustion chamber and at autogenic temperature to mix with additional, partially heated air to complete the combustion process. The exhaust route for the combustion gases is elongated and doubled back upon itself to delay discharge and allow sufficient time to effectively heat exchange with the thermal energy transport and distribution medium.

  9. Sizing a water softener for aquifer thermal energy storage

    SciTech Connect

    Hall, S.H.; Jenne, E.A.

    1993-03-01

    In aquifer thermal energy storage (ATES) installations, ground water is circulated between an aquifer and heat exchangers via a well field. It is often necessary to soften the water to prevent carbonate scaling in pipes, heat exchangers, and well screens. Most ATES projects requiring water softening will be best served by using synthetic ion-exchange resins. The size of the resin beds, the resin regeneration cycle, and the amount of NaCl brine used in each regeneration depend on several factors. These are (1) the chemistry of the native ground water, (2) allowable residual hardness after softening, (3) the maximum flow rate of water through the ATES plant, and (4) exchange characteristics of the resin. Example calculations are given for a three-bed water softening system.

  10. Shelf mounted ocean thermal energy conversion platform, revised preliminary report

    NASA Astrophysics Data System (ADS)

    1984-03-01

    This report relates model tests of a generic Ocean Thermal Energy Conversion (OTEC) platform. The objective of these tests is to aid in the evaluation of new OTEC designs and to present a data base for design purposes. The test plant has been designed to provide a data base for comparison with current and projected analytical tools as well as comparisons of results from one model configuration to another. The new conceptual OTEC designs are different from the typical offshore (jacket type) structure which is quite transparent to waves. The major difference is the addition of large submerged power production modules to the frame. These proposed modules offer a large surface area to obstruct the flow and thereby increase the global wave forces acting on the structure.

  11. Design and installation manual for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Cole, R. L.; Nield, K. J.; Rohde, R. R.; Wolosewicz, R. M.

    1980-01-01

    The design and installation of thermal energy storage in active solar systems is discussed. Both air based and liquid based systems are covered with topics on designing rock beds, tank types, pump and fan selection, installation, costs, and operation and maintenance. Topics relevant to latent heat storage include properties of phase change materials, sizing the storage unit, insulating the storage unit, available systems, and cost. Topics relevant to heating domestic water include safety, single-, and dual-tank systems, domestic water heating with air and liquid based space heating systems, and stand alone domestics hot water systems. Also examined are common problems with storage systems and their solutions, heat transfer fluid properties, economic insulation thickness, heat exchanger sizing, and sample specifications for heat exchangers, wooden rock bins, steel tanks, concrete tanks, and fiberglass reinforced plastic tanks.

  12. Direct contact heat transfer for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Wright, J. D.

    1982-03-01

    Direct contact heat exchange offers the potential for increased efficiency and lower heat transfer costs in a variety of thermal energy storage systems. SERI models of direct contact heat transfer based on literature information identified dispersed phase drop size, the mechanism of heat transfer within the drop, and dispersed phase holdup as the parameters controlling direct contact system performance. Tests were defined and equipment constructed to provide independent determination of drop size, heat transfer mechanism, and hold up. Further experiments are needed to conclusively determine whether the salt in a salt hydrate melt acts to block internal circulation. The potential of low temperature oil/salt hydrate latent heat storage systems is being evaluated in the laboratory.

  13. Direct contact heat transfer for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Wright, J. D.

    1980-11-01

    Direct contact heat exchange offers the potential for increased efficiency and lower heat transfer costs in a variety of thermal energy storage systems. Models of direct contact heat transfer based on literature information identified dispersed phase drop size, the mechanism of heat transfer within the drop, and dispersed phase holdup as the parameters controlling direct contact system performance. Tests were defined and equipment constructed to provide independent determination of drop size, heat transfer mechanism, and hold up. Experiments with heptane dispersed in water are described. The velocity at which drop formation changes from dropwise to jetting was overpredicted by all literature correlations. Further experiments are needed to conclusively determine whether the salt in a salt hydrate melt acts to block internal circulation. In addition, the potential of low temperature oil/salt hydrate latent heat storage systems is evaluated in the laboratory.

  14. Evaluation of thermal energy storage materials for advanced compressed air energy storage systems

    SciTech Connect

    Zaloudek, F.R.; Wheeler, K.R.; Marksberry, L.

    1983-03-01

    Advanced Compressed-Air Energy Storage (ACAS) plants have the near-term potential to reduce the fuel consumption of compressed-air plants from 33 to 100%, depending upon their design. Fuel is saved by storing some or all of the heat of compression as sensible heat which is subsequently used to reheat the compressed air prior to expansion in the turbine generator. The thermal storage media required for this application must be low cost and durable. The objective of this project was to screen thermal store materials based on their thermal cycle durability, particulate formation and corrosion resistant characteristics. The materials investigated were iron oxide pellets, Denstone pebbles, cast-iron balls, and Dresser basalt rock. The study specifically addressed the problems of particle formation and thermal ratcheting of the materials during thermal cycling and the chemical attack on the materials by the high temperature and moist environment in an ACAS heat storage bed. The results indicate that from the durability standpoint Denstone, cast iron containing 27% or more chromium, and crushed Dresser basalt would possibly stand up to ACAS conditions. If costs are considered in addition to durability and performance, the crushed Dresser basalt would probably be the most desirable heat storage material for adiabatic and hybrid ACAS plants, and more in-depth longer term thermal cycling and materials testing of Dresser basalt is recommended. Also recommended is the redesign and costing analysis of both the hybrid and adiabatic ACAS facilities based upon the use of Dresser basalt as the thermal store material.

  15. Impact of seasonal scarcity on energy balance and body composition in peasant adolescents from Calakmul, Campeche Mexico.

    PubMed

    Gamboa, José A Alayón; García, Francisco D Gurri

    2007-01-01

    A time allocation and anthropometric study were performed on 46 male and 38 female adolescents from 16 peasant households from two different adaptive strategies in the municipio of Calakmul, Campeche Mexico to see if they could maintain energy balance during the annual scarcity season. These strategies were called: "household subsistence agricultural strategy" (HSA) and "household commercial agricultural strategy" (HCA). Each month, from June 2001 to May 2002, adolescents were measured and followed for 24 h. Their activities were recorded at 15 min intervals. Weight for age (W/A), height for age (H/A), body mass index (BMI), arm muscle area, arm fat area, total energy expenditure (TEE), activity energy expenditure (AEE), and basal metabolic rate (BMR) were estimated and the data compared between seasons using a repeated measurements analysis of variance. The results suggest that HCA offers their adolescents better buffering against seasonal scarcity, and that HSA males are better protected than females. HCA adolescents didn't show significant losses of weight, and HCA females lost body fat during the scarcity season. HSA vulnerability was observed in W/A and BMI z score reductions during the scarcity season. It also reflected itself in stunted adolescent males and adolescent females with fewer fat reserves. HSA adolescents reduced their BMR to down regulate their energy expenditure during the scarcity season without reducing TEE and physical activity levels. HSA females lost muscle mass during the scarcity season while HSA males didn't. This difference was associated with a more demanding work schedule throughout the year for females.

  16. High-temperature thermal destruction of poultry derived wastes for energy recovery in Australia.

    PubMed

    Florin, N H; Maddocks, A R; Wood, S; Harris, A T

    2009-04-01

    The high-temperature thermal destruction of poultry derived wastes (e.g., manure and bedding) for energy recovery is viable in Australia when considering resource availability and equivalent commercial-scale experience in the UK. In this work, we identified and examined the opportunities and risks associated with common thermal destruction techniques, including: volume of waste, costs, technological risks and environmental impacts. Typical poultry waste streams were characterised based on compositional analysis, thermodynamic equilibrium modelling and non-isothermal thermogravimetric analysis coupled with mass spectrometry (TG-MS). Poultry waste is highly variable but otherwise comparable with other biomass fuels. The major technical and operating challenges are associated with this variability in terms of: moisture content, presence of inorganic species and type of litter. This variability is subject to a range of parameters including: type and age of bird, and geographical and seasonal inconsistencies. There are environmental and health considerations associated with combustion and gasification due to the formation of: NO(X), SO(X), H(2)S and HCl gas. Mitigation of these emissions is achievable through correct plant design and operation, however, with significant economic penalty. Based on our analysis and literature data, we present cost estimates for generic poultry-waste-fired power plants with throughputs of 2 and 8 tonnes/h.

  17. Assessing District Energy Systems Performance Integrated with Multiple Thermal Energy Storages

    NASA Astrophysics Data System (ADS)

    Rezaie, Behnaz

    The goal of this study is to examine various energy resources in district energy (DE) systems and then DE system performance development by means of multiple thermal energy storages (TES) application. This study sheds light on areas not yet investigated precisely in detail. Throughout the research, major components of the heat plant, energy suppliers of the DE systems, and TES characteristics are separately examined; integration of various configurations of the multiple TESs in the DE system is then analysed. In the first part of the study, various sources of energy are compared, in a consistent manner, financially and environmentally. The TES performance is then assessed from various aspects. Then, TES(s) and DE systems with several sources of energy are integrated, and are investigated as a heat process centre. The most efficient configurations of the multiple TESs integrated with the DE system are investigated. Some of the findings of this study are applied on an actual DE system. The outcomes of this study provide insight for researchers and engineers who work in this field, as well as policy makers and project managers who are decision-makers. The accomplishments of the study are original developments TESs and DE systems. As an original development the Enviro-Economic Function, to balance the economic and environmental aspects of energy resources technologies in DE systems, is developed; various configurations of multiple TESs, including series, parallel, and general grid, are developed. The developed related functions are discharge temperature and energy of the TES, and energy and exergy efficiencies of the TES. The TES charging and discharging behavior of TES instantaneously is also investigated to obtain the charging temperature, the maximum charging temperature, the charging energy flow, maximum heat flow capacity, the discharging temperature, the minimum charging temperature, the discharging energy flow, the maximum heat flow capacity, and performance

  18. Seasonal and Spatial Changes of Planktonic Bacterial Communities Inhabiting the Natural Thermal Lake Hévíz, Hungary.

    PubMed

    Krett, Gergely; Nagymáté, Zsuzsanna; Márialigeti, Károly; Borsodi, Andrea K

    2016-03-01

    Lake Hévíz is a unique thermal spa located in Hungary. Owing to the thermal springs nourishing the lake, it has a relatively rapid water turnover. In spring 2011 a comprehensive embankment reconstruction was performed to preserve the water supply of the surrounding wetland habitats. The physical and chemical parameters as well as the planktonic microbial communities were studied with special respect to the effect of the disturbance of the water of Lake Hévíz. According to the abiotic components, both temporal and spatial differences were revealed with the exception of autumn samples. The reconstruction resulted in a short term but dramatic alteration of the total planktonic bacterial and cyanobacterial community structures as revealed by denaturing gradient gel electrophoresis. In addition, greater seasonal than spatial differences of bacterial communities were also observed. Planktonic bacterial community composition of Lake Hévíz included mainly typical freshwater species within phylum Actinobacteria, Chloroflexi, Cyanobacteria and class Alpha-, Beta- and Gamma-proteobacteria. Most of them were aerobic or facultative anaerobic heterotrophic but chemolitotrophic (e.g. Thiobacillus) or photolithotrophic (e.g. Cyanobacteria and Chloroflexi) autotrophic microbes were also identified.

  19. Initial Study Of Potency Thermal Energy Using OTEC (Ocean Thermal Energy Conversion) As A Renewable Energy For Halmahera Indonesia

    NASA Astrophysics Data System (ADS)

    Andrawina, Y. O.; Sugianto, D. N.; Alifdini, I.

    2017-02-01

    The Blue Energy is the one of renewable energy. Indonesia as a maritime country has many potention to implement this Blue energy, but it still an advance technology to convert this energy into the electricity. The concept of OTEC with Land Based System is to boost the cost effectiveness of ocean technology. OTEC Land based system which is integrated with the cooling system, water desalination systems, aquaculture, and agriculture. Geographically Halmahera district is located in the Eastern Province of North Maluku. Halmahera is the one of remote island in Indonesia that still lack of electricity. By processing the Argo Float data in 2013-2015 using ODV (Ocean Data View) software, shows the difference of ocean temperature in Halmahera sea surface the range is 29°C. In depth of 1000 m, the sea temperature ranging from 2°C. The Electrical potential of OTEC a long 55 km Halmahera beach are around 93,1% as potential source of OTEC technology. The electricity OTEC prediction is 5,12 MW. Capacity factor of OTEC is 0.857, means that Halmahera have electrical potential for applying OTEC for each year is 35,88 GWh/year.

  20. The Influence of Seasonal Climatic Parameters on the Permafrost Thermal Regime in West Siberia

    NASA Astrophysics Data System (ADS)

    Popova, V. V.; Shmakin, A. B.

    2009-12-01

    Statistical correlations between seasonal air temperatures and snow depths and active layer depths and permafrost temperatures were analyzed for tundra (Marre-Salle) and northern taiga (Nadym) sites in Western Siberia. Interannual variations in active layer depth in the tundra zone correlated with the average air temperature of the current summer, and in peatland and humid tundra, also with summer temperatures of the preceding 1-2 years. In the northern taiga zone, the active layer depth related to current summer air temperature and to a lesser extent, to spring and/or winter air temperatures. Variations in summer permafrost temperatures at 5-10m depth were correlated with spring air temperatures in the current and preceding 1-2 years. The weather regime during the preceding 1-2 years, therefore, reinforced or weakened ground temperature variations in a given year. Overall, the most important factors influencing the permafrost regime were spring and summer air temperatures, and in one case snow depth. However, statistical links between meteorological and permafrost parameters varied between the tundra and northern taiga zones and among landscape types within each zone, emphasizing the importance of analyses at short temporal scales and for individual terrain units.

  1. Multi-Fluid Geo-Energy Systems for Bulk and Thermal Energy Storage and Dispatchable Renewable and Low-Carbon Electricity

    NASA Astrophysics Data System (ADS)

    Buscheck, T. A.; Randolph, J.; Saar, M. O.; Hao, Y.; Sun, Y.; Bielicki, J. M.

    2014-12-01

    Integrating renewable energy sources into electricity grids requires advances in bulk and thermal energy storage technologies, which are currently expensive and have limited capacity. We present an approach that uses the huge fluid and thermal storage capacity of the subsurface to harvest, store, and dispatch energy from subsurface (geothermal) and surface (solar, nuclear, fossil) thermal resources. CO2 captured from fossil-energy systems and N2 separated from air are injected into permeable formations to store pressure, generate artesian flow of brine, and provide additional working fluids. These enable efficient fluid recirculation, heat extraction, and power conversion, while adding operational flexibility. Our approach can also store and dispatch thermal energy, which can be used to levelize concentrating solar power and mitigate variability of wind and solar power. This may allow low-carbon, base-load power to operate at full capacity, with the stored excess energy being available to addresss diurnal and seasonal mismatches between supply and demand. Concentric rings of horizontal injection and production wells are used to create a hydraulic divide to store pressure, CO2, N2, and thermal energy. Such storage can take excess power from the grid and excess thermal energy, and dispatch that energy when it is demanded. The system is pressurized and/or heated when power supply exceeds demand and depressurized when demand exceeds supply. Supercritical CO2 and N2 function as cushion gases to provide enormous pressure-storage capacity. Injecting CO2 and N2 displaces large quantities of brine, reducing the use of fresh water. Geologic CO2 storage is a crucial option for reducing CO2 emissions, but valuable uses for CO2 are needed to justify capture costs. The initial "charging" of our system requires permanently isolating large volumes of CO2 from the atmosphere and thus creates a market for its disposal. Our approach is designed for locations where a permeable

  2. Substantial energy input to the mesopelagic ecosystem from the seasonal mixed-layer pump

    PubMed Central

    Dall’Olmo, Giorgio; Dingle, James; Polimene, Luca; Brewin, Robert J.W.; Claustre, Hervé

    2016-01-01

    The “mesopelagic” is the region of the ocean between about 100 and 1000 m that harbours one of the largest ecosystems and fish stocks on the planet1,2. This vastly unexplored ecosystem is believed to be mostly sustained by chemical energy, in the form of fast-sinking particulate organic carbon, supplied by the biological carbon pump3. Yet, this supply appears insufficient to match mesopelagic metabolic demands4–6. The mixed-layer pump is a physically-driven biogeochemical process7–11 that could further contribute to meet these energetic requirements. However, little is known about the magnitude and spatial distribution of this process at the global scale. Here we show that the mixed-layer pump supplies an important seasonal flux of organic carbon to the mesopelagic. By combining mixed-layer depths from Argo floats with satellite retrievals of particulate organic carbon, we estimate that this pump exports a global flux of about 0.3 Pg C yr−1 (range 0.1 – 0.5 Pg C yr−1). In high-latitude regions where mixed-layers are deep, this flux is on average 23%, but can be greater than 100% of the carbon supplied by fast sinking particles. Our results imply that a relatively large flux of organic carbon is missing from current energy budgets of the mesopelagic. PMID:27857779

  3. Solar energy system performance evaluation: seasonal report for Elcam Tempe Arizona State University, Tempe, Arizona

    SciTech Connect

    Not Available

    1980-05-01

    The analysis used is based on instrumented system data monitored and collected for at least one full season of operation. The objective of the analysis is to report the long-term field performance of the installed system and to make technical contributions to the definition of techniques and requirements for solar energy system design. The solar system, Elcam-Tempe, was designed to supply commercial domestic hot water heating systems that utilize two, four by eight foot flat plate collectors to heat water in a fifty-two gallon preheat tank or a fifty-two gallon domestic hot water (DHW) tank. The DHW tank provides hot water to the Agriculture Department residence at Arizona State University. The system uses an automatic cascade control system to control three independent actuators, the coolant circulation pump, the cascade valve, and the electric heating element. The system provides freeze protection by automatically circulating hot water from the hot water tank through the collectors when the collector outlet temperature is below a specified value. The building is a single story residence located at the agriculture experiment farm of the Arizona State University. The Elcam-Tempe Solar Energy System has four modes of operation.

  4. Enhanced photovoltaic energy conversion using thermally based spectral shaping

    NASA Astrophysics Data System (ADS)

    Bierman, David M.; Lenert, Andrej; Chan, Walker R.; Bhatia, Bikram; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N.

    2016-06-01

    Solar thermophotovoltaic devices have the potential to enhance the performance of solar energy harvesting by converting broadband sunlight to narrow-band thermal radiation tuned for a photovoltaic cell. A direct comparison of the operation of a photovoltaic with and without a spectral converter is the most critical indicator of the promise of this technology. Here, we demonstrate enhanced device performance through the suppression of 80% of unconvertible photons by pairing a one-dimensional photonic crystal selective emitter with a tandem plasma-interference optical filter. We measured a solar-to-electrical conversion rate of 6.8%, exceeding the performance of the photovoltaic cell alone. The device operates more efficiently while reducing the heat generation rates in the photovoltaic cell by a factor of two at matching output power densities. We determined the theoretical limits, and discuss the implications of surpassing the Shockley-Queisser limit. Improving the performance of an unaltered photovoltaic cell provides an important framework for the design of high-efficiency solar energy converters.

  5. Environmental programs for ocean thermal energy conversion (OTEC)

    SciTech Connect

    Wilde, P.

    1981-07-01

    The environmental research effort in support of the US Department of Energy's Ocean Thermal Energy Conversion (OTEC) program has the goal of providing documented information on the effect of proposed operations on the ocean and the effect of oceanic conditions on the plant. The associated environment program consists of archival studies in potential areas serial oceanographic cruises to sites or regions of interest, studies from various fixed platforms at sites, and compilation of such information for appropriate legal compliance and permit requirements and for use in progressive design of OTEC plants. Site/regions investigated are south of Mobile and west of Tampa, Gulf of Mexico; Punta Tuna, Puerto Rico; St. Croix, Virgin Islands; Kahe Point, Oahu and Keahole Point, Hawaii, Hawaiian Islands; and off the Brazilian south Equatorial Coast. Four classes of environmental concerns identified are: redistribution of oceanic properties (ocean water mixing, impingement/entrainment etc.); chemical pollution (biocides, working fluid leaks, etc.); structural effects (artificial reef, aggregation, nesting/migration, etc.); socio-legal-economic (worker safety, enviromaritime law, etc.).

  6. Design and installation manual for thermal energy storage

    SciTech Connect

    Cole, R L; Nield, K J; Rohde, R R; Wolosewicz, R M

    1980-01-01

    The purpose of this manual is to provide information on the design and installation of thermal energy storage in active solar systems. It is intended for contractors, installers, solar system designers, engineers, architects, and manufacturers who intend to enter the solar energy business. The reader should have general knowledge of how solar heating and cooling systems operate and knowledge of construction methods and building codes. Knowledge of solar analysis methods such as f-Chart, SOLCOST, DOE-1, or TRNSYS would be helpful. The information contained in the manual includes sizing storage, choosing a location for the storage device, and insulation requirements. Both air-based and liquid-based systems are covered with topics on designing rock beds, tank types, pump and fan selection, installation, costs, and operation and maintenance. Topics relevant to latent heat storage include properties of phase-change materials, sizing the storage unit, insulating the storage unit, available systems, and cost. Topics relevant to heating domestic water include safety, single- and dual-tank systems, domestic water heating with air- and liquid-based space heating systems, and stand alone domestics hot water systems. Several appendices present common problems with storage systems and their solutions, heat transfer fluid properties, economic insulation thickness, heat exchanger sizing, and sample specifications for heat exchangers, wooden rock bins, steel tanks, concrete tanks, and fiberglass-reinforced plastic tanks.

  7. Ocean thermal energy conversion: Historical highlights, status, and forecast

    SciTech Connect

    Dugger, G.L.; Avery, W.H.; Francis, E.J.; Richards, D.

    1983-07-01

    In 1881, d'Arsonval conceived the closed-Rankine-cycle ocean thermal energy conversion (OTEC) system in which a working fluid is vaporized by heat exchange with cold water drawn from a 700-1200 m depth. In 1930, Claude demonstrated an open-cycle process in Cuba. Surface water was flash-vaporized at 3 kPa to drive a turbine directly (no secondary working fluid) and then was condensed by direct contact with water drawn from a 700-m depth through a 1.6m-diam, 1.75-km-long cold-water pipe (CWP). From a delta T of 14/sup 0/C his undersized turbine generated 22 kW. In 1956 a French team designed a 3.5-MW (net) open-cycle plant for installation off Abidjan on the Ivory Coast of Africa and demonstrated the necessary CWP deployment. The at-sea demonstrations by Mini-OTEC and OTEC-1 and other recent advances in OTEC technology summarized herein represent great progress. All of the types of plants proposed for the DOE's PON program may be worthy of development; certainly work on a grazing plant is needed. Our estimates indicate that the U.S. goals established by Public Law 96-310 leading to 10 GW of OTEC power and energy product equivalents by 1999 are achievable, provided that adequate federal financial incentives are retained to assure the building of the first few plants.

  8. Off seasonal and pre-seasonal assessment of circulating energy sources during prolonged running at the anaerobic threshold in competitive triathletes

    PubMed Central

    Knoepfli, B; Riddell, M; Ganzoni, E; Burki, A; Villiger, B; von Duvillard, S P

    2004-01-01

    Objectives: To compare changes in circulating energy sources during prolonged exercise in off season (OS) and pre-season (PS) training of triathletes. Methods: Nine athletes of the Swiss national triathlon team (three female, mean (SD) age 28.7 (4.9) years, height 169.8 (6.0) cm, weight 57.0 (6.2) kg, V·O2MAX 66.5 (5.3) ml/min/kg; six male, mean (SD) age 24.0 (4.1) years, height 181.4 (6.9) cm, weight 73.5 (6.0) kg, V·O2MAX 75.9 (4.9) ml/min/kg) were tested twice (2.5 months apart) during a 25 km aerobic capacity test run at the end of the OS and just before the season. The average training load during the OS was 9.9 h/week, and this increased to 14.4 h/week in the PS. With heart rates as reference, exercise intensity during the aerobic capacity test was 97.0 (4.9)% of the anaerobic threshold and 91.2 (4.5)% of V·O2MAX. Blood samples were collected before, during, and after the aerobic capacity test. Samples were collected every 5 km during three minute rest intervals. Results: Blood was analysed for triglyceride (TG), free fatty acids, cholesterol, high density lipoprotein cholesterol, glucose, insulin, lactate, and changes in plasma volume. A two factor (season by distance) repeated measures analysis of variance revealed an increase in capacity for prolonged exercise in the PS by a decrease in running intensity during the aerobic capacity test (% of speed at 2.0 mmol/l lactate threshold, p = 0.008), an increase in running speed at the anaerobic threshold (p = 0.003) and at 4.0 and 2.0 mmol/l (p<0.001) of the lactate threshold. A significant season by distance interaction was found for TG (p<0.001). TG concentrations peaked at 5 km and decreased logarithmically throughout the OS (1.48 (0.34) to 0.86 (0.20) mmol/l) and PS (1.90 (0.31) to 0.73 (0.18) mmol/l) tests. From the OS to the PS, there was an increase in the difference in TG at 5–15 km with a concomitant increase at 2.0 mmol/l of the lactate threshold. The peak TG concentrations at 5 km followed by a

  9. Numerical and experimental studies of liquid storage tank thermal stratification for a solar energy system

    SciTech Connect

    Wu, S T; Han, S M

    1980-11-01

    The results of theoretical and experimental studies of thermal stratification in liquid energy storage tanks for the performance of solar energy systems are presented. The investigation was divided into three areas: (1) Justification of the Importance of Thermal Stratification Inside the Energy Storage Tanks, (II) Development of a Simple Mathematical Model which is Compatible with Existing Solar Energy System Simulation Code, and (III) Validation of Mathematical Models by Experimental Data Obtained from Realistic Solar Energy System Operations.

  10. A RESEARCH PLAN FOR THE USE OF THERMAL AVHRR IMAGERY TO STUDY ANNUAL AND SEASONAL MEAN SURFACE TEMPERATURES FOR LARGE LAKES IN NORTH AMERICA

    EPA Science Inventory

    Surface and vertical temperature data will be obtained from several large lakes With surface areas large enough to be effectively sampled with AVHRR imagery. Yearly and seasonal patterns of surface and whole water column thermal values will be compared to estimates of surface tem...

  11. Seasonal variation in energy expenditure and body composition in captive White Storks (Ciconia ciconia).

    PubMed

    Mata, Astolfo; Massemin-Challet, Sylvie; Caloin, Michel; Michard-Picamelot, Delphine; Le Maho, Yvon

    2010-01-01

    North Western European populations of White Storks (Ciconia ciconia) appear to have been saved from extinction by settling, i.e. stopping migration. Settled storks exposed to winter conditions must cope with periods of potentially high energy demands that would otherwise be avoided by the migration process. Doubly labeled water (DLW) was therefore used to examine the seasonal variation (summer vs winter) in daily energy expenditure (DEE) and the body composition of adult and immature storks of both sexes. Male White Storks showed a higher DEE over the winter period than in summer compared with females; in particular, immature males exhibited greater energy expenditure in winter than adult males. Thus, the DEE did not significantly differ between summer and winter (except for immature males), reflecting an absence of thermoregulation cost in winter. For both age classes, total body mass increased in winter, which was mainly due to an increase in fat mass. Adult storks were 5% heavier than immature storks. The sexes differed in body mass, with males weighing significantly more than females by 11%. Mean LBM (lean body mass) was 8.5% higher in adults than in immatures, and was 11.5% higher in males compared with females. Between their first and second summers, immatures accumulated a lean body mass to finally reach the same values as adults, indicating a phase of muscle development. The mean fat mass of the storks did not differ between age classes or between sexes. Based on physiological parameters, this study shows that settled White Storks are able to cope with mild winter periods when they are artificially provided with food. In a view to preserve favourable habitats for this species, it is therefore necessary to decide on a plan of action for breeding areas.

  12. Solar energy system performance evaluation: Seasonal report for IBM system 1A, Huntsville, Alabama

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The operational and thermal performance of the solar energy system, Sims Prototype System 1A, is described. The system was designed by IBM to provide 50 to 60 percent of the space heating and domestic hot water preheating load to a 2,000 square foot floor space single family residence in the Huntsville area. The load design temperature inside the building was to be maintained at 70 degrees fahrenheit with auxiliary energy for heating supplied by an electric heat pump assisted by an electric resistance strip heater. In general the disappointing operation of this system is attributed to the manner in which it was used. The system was designed for residential application and used to satisfy the demands of an office environment. The differences were: (1) inside temperature was not maintained at 70 F as expected; and (2) hot water usage was much lower than expected. The conclusion is that the solar energy system must be designed for the type of application in which it is used. Misapplication usually will have an adverse affect on system performance.

  13. Solar energy system performance evaluation: Seasonal report for IBM system 1A, Huntsville, Alabama

    NASA Astrophysics Data System (ADS)

    1980-05-01

    The operational and thermal performance of the solar energy system, Sims Prototype System 1A, is described. The system was designed by IBM to provide 50 to 60 percent of the space heating and domestic hot water preheating load to a 2,000 square foot floor space single family residence in the Huntsville area. The load design temperature inside the building was to be maintained at 70 degrees fahrenheit with auxiliary energy for heating supplied by an electric heat pump assisted by an electric resistance strip heater. In general the disappointing operation of this system is attributed to the manner in which it was used. The system was designed for residential application and used to satisfy the demands of an office environment. The differences were: (1) inside temperature was not maintained at 70 F as expected; and (2) hot water usage was much lower than expected. The conclusion is that the solar energy system must be designed for the type of application in which it is used. Misapplication usually will have an adverse affect on system performance.

  14. Guidelines for conceptual design and evaluation of aquifer thermal energy storage

    SciTech Connect

    Meyer, C.F.; Hauz, W.

    1980-10-01

    Guidelines are presented for use as a tool by those considering application of a new technology, aquifer thermal energy storage (ATES). The guidelines will assist utilities, municipalities, industries, and other entities in the conceptual design and evaluation of systems employing ATES. The potential benefits of ATES are described, an overview is presented of the technology and its applications, and rules of thumb are provided for quickly judging whether a proposed project has sufficient promise to warrant detailed conceptual design and evaluation. The characteristics of sources and end uses of heat and chill which are seasonally mismatched and may benefit from ATES (industrial waste heat, cogeneration, solar heat, and winter chill, for space heating and air conditioning) are discussed. Storage and transport subsystems and their expected performance and cost are described. A 10-step methodology is presented for conceptual design of an ATES system and evaluation of its technical and economic feasibility in terms of energy conservation, cost savings, fuel substitution, improved dependability of supply, and abatement of pollution, with examples, and the methodology is applied to a hypothetical proposed ATES system, to illustrate its use.

  15. Seasonal Evolution and Energy Budget of the South Residual Polar Cap of Mars from CRISM and HiRISE Observations

    NASA Astrophysics Data System (ADS)

    Pilorget, C.; Douté, S.; Vincendon, M.

    2016-09-01

    Here we use both HiRISE and CRISM data from the south residual cap to investigate its seasonal behavior (e.g. albedo increase) and determine its energy budget through the retrieval of the directional-hemispheric surface ice albedo.

  16. A Literature Review of Sealed and Insulated Attics—Thermal, Moisture and Energy Performance

    SciTech Connect

    Less, Brennan; Walker, Iain; Levinson, Ronnen

    2016-08-01

    . Energy performance is expected to be roughly equivalent between sealed and insulated attics and prescriptive advanced roof/attic options in Title 24 2016. System performance can also be expected to improve, such as pull down time, performance at peak load, etc. We expect benefits to be reduced for all advanced roof/attic approaches, relative to a traditional vented attic, as duct system leakage is reduced close to 0. The most recent assessments, comparing advanced roof/attic assemblies to code compliant vented attics suggest average 13% TDV energy savings, with substantial variation by climate zone (more savings in more extreme climates). Similar 6-11% reductions in seasonally adjusted HVAC duct thermal losses have been measured in a small subset of such California homes using the ducts in conditioned space approach. Given the limited nature of energy and moisture monitoring in sealed and insulated attic homes, there is crucial need for long-term data and advanced modeling of these approaches in the California new and existing home contexts.

  17. Fluctuations in daily energy intake do not cause physiological stress in a Neotropical primate living in a seasonal forest.

    PubMed

    Martínez-Mota, Rodolfo; Righini, Nicoletta; Palme, Rupert

    2016-12-01

    Animals may face periods of nutritional stress due to short-term food shortage and/or low energy consumption associated with seasonal fluctuations in resource availability. We tested the hypothesis that periods of restricted macronutrient and energy intake result in energy deficits and physiological stress in wild black howler monkeys (Alouatta pigra) inhabiting seasonal tropical semi-deciduous forests. We conducted full-day follows of focal animals recording feeding rates, time spent feeding, and total amount of food ingested. We carried out nutritional analysis of foods collected from feeding trees and calculated the daily nutrient and energy intake of each focal individual. Fecal glucocorticoid metabolites (fGCM) of focal animals were used as an indicator of physiological stress. We found that fluctuations in daily energy intake across seasons did not have significant effects on fGCM of individuals. However, protein intake was negatively associated with fGCM, highlighting the interplay among macronutrients, metabolism, and the endocrine system. Fecal glucocorticoid metabolites were also positively related to fruit availability, but this relationship was most likely due to social stress associated with intergroup encounters and resource defense that occurred when preferred trees were fruiting. Behavioral strategies such as dietary shifts and nutrient mixing, and metabolic adaptations such as low energy expenditure allowed individuals to fulfill their minimum energy requirements even during periods of decreased resource availability and intake. The present study suggests that seasonal variations in food, macronutrient, and energy acquisition may have limited physiological costs for animals that exploit different types of plant resources such as howler monkeys.

  18. Composition, seasonal change, and bathymetry of Ligeia Mare, Titan, derived from its microwave thermal emission

    NASA Astrophysics Data System (ADS)

    Le Gall, A.; Malaska, M. J.; Lorenz, R. D.; Janssen, M. A.; Tokano, T.; Hayes, A. G.; Mastrogiuseppe, M.; Lunine, J. I.; Veyssière, G.; Encrenaz, P.; Karatekin, O.

    2016-02-01

    For the last decade, the passive radiometer incorporated in the Cassini RADAR has recorded the 2.2 cm wavelength thermal emission from Titan's seas. In this paper, we analyze the radiometry observations collected from February 2007 to January 2015 over one of these seas, Ligeia Mare, with the goal of providing constraints on its composition, bathymetry, and dynamics. In light of the depth profile obtained by Mastrogiuseppe et al. (2014) and of a two-layer model, we find that the dielectric constant of the sea liquid is <1.8, and its loss tangent is <3.6-2.1+4.3×10-5. Both results point to a composition dominated by liquid methane rather than ethane. A high methane concentration suggests that Ligeia Mare is primarily fed by methane-rich precipitation and/or ethane has been removed from it (e.g., by crustal interaction). Our result on the dielectric constant of the seafloor is less constraining (<2.9-0.9+0.9), but we favor a scenario where the floor of Ligeia Mare is covered by a sludge of compacted and possibly nitrile-rich organic material formed by the deposition of photochemical haze or by rain washing of the nearby shores. We use these results to produce a low-resolution bathymetry map of the sea. We also estimate the temperature variation of the bulk sea between February 2007 and July 2013 to be <2 K, which provides a constraint on its net evaporative cooling currently being explored in ocean circulation models. Lastly, we suggest a lag in the summer warming of the northern polar terrains.

  19. Seasonal variation of energy reserves and reproduction in neotropical free-tailed bats Molossus molossus (Chiroptera: Molossidae).

    PubMed

    Barros, M S; Morais, D B; Araújo, M R; Carvalho, T F; Matta, S L P; Pinheiro, E C; Freitas, M B

    2013-08-01

    Seasonal variation is a key factor regulating energy metabolism and reproduction in several mammals, including bats. This study aimed to track seasonal changes in the energy reserves of the insectivorous bat Molossus molossus associated with its reproductive cycle. Adult males were collected during the four neotropical annual seasons in Viçosa - MG, Brazil. Blood and tissues were collected for metabolic analysis and testes were removed for histology and morphometry. Our results show that liver and breast muscle glycogen concentrations were significantly lower in winter. The adiposity index was significantly higher in the fall compared to winter and spring. Seminiferous tubules were greater in diameter in animals captured in fall and winter, indicating a higher investment in spermatic production during these seasons. The percentage of Leydig cells was higher in summer compared to fall and winter. We suggest that M. molossus presents a type of seasonal reproduction with two peaks of testicular activity: one in fall, with higher sperm production (spermatogenesis), and another in summer, with higher hormone production (steroidogenesis). The metabolic pattern may be associated with reproductive events, especially due to the highest fat storage observed in the fall, which coincides with the further development of the seminiferous tubules.

  20. Applying an energy balance model of a debris covered glacier through the Himalayan seasons - insights from the field and sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Steiner, Jakob; Pellicciotti, Francesca; Buri, Pascal; Brock, Ben

    2016-04-01

    Although some recent studies have attempted to model melt below debris cover in the Himalaya as well as the European Alps, field measurements remain rare and uncertainties of a number of parameters are difficult to constrain. The difficulty of accurately measuring sub-debris melt at one location over a longer period of time with stakes adds to the challenge of calibrating models adequately, as moving debris tends to tilt stakes. Based on measurements of sub-debris melt with stakes as well as air and surface temperature at the same location during three years from 2012 to 2014 at Lirung Glacier in the Nepalese Himalaya, we investigate results with the help of an earlier developed energy balance model. We compare stake readings to cumulative melt as well as observed to modelled surface temperatures. With timeseries stretching through the pre-Monsoon, Monsoon and post-Monsoon of different years we can show the difference of sensitive parameters during these seasons. Using radiation measurements from the AWS we can use a temporarily variable time series of albedo. A thorough analysis of thermistor data showing the stratigraphy of the temperature through the debris layer allows a detailed discussion of the variability as well as the uncertainty range of thermal conductivity. Distributed wind data as well as results from a distributed surface roughness assessment allows to constrain variability of turbulent fluxes between the different locations of the stakes. We show that model results are especially sensitive to thermal conductivity, a value that changes substantially between the seasons. Values obtained from the field are compared to earlier studies, which shows large differences within locations in the Himalaya. We also show that wind varies with more than a factor two between depressions and on debris mounds which has a significant influence on turbulent fluxes. Albedo decreases from the dry to the wet season and likely has some spatial variability that is

  1. Seasonally-Dynamic Presence-Only Species Distribution Models for a Cryptic Migratory Bat Impacted by Wind Energy Development.

    PubMed

    Hayes, Mark A; Cryan, Paul M; Wunder, Michael B

    2015-01-01

    Understanding seasonal distribution and movement patterns of animals that migrate long distances is an essential part of monitoring and conserving their populations. Compared to migratory birds and other more conspicuous migrants, we know very little about the movement patterns of many migratory bats. Hoary bats (Lasiurus cinereus), a cryptic, wide-ranging, long-distance migrant, comprise a substantial proportion of the tens to hundreds of thousands of bat fatalities estimated to occur each year at wind turbines in North America. We created seasonally-dynamic species distribution models (SDMs) from 2,753 museum occurrence records collected over five decades in North America to better understand the seasonal geographic distributions of hoary bats. We used 5 SDM approaches: logistic regression, multivariate adaptive regression splines, boosted regression trees, random forest, and maximum entropy and consolidated outputs to generate ensemble maps. These maps represent the first formal hypotheses for sex- and season-specific hoary bat distributions. Our results suggest that North American hoary bats winter in regions with relatively long growing seasons where temperatures are moderated by proximity to oceans, and then move to the continental interior for the summer. SDMs suggested that hoary bats are most broadly distributed in autumn-the season when they are most susceptible to mortality from wind turbines; this season contains the greatest overlap between potentially suitable habitat and wind energy facilities. Comparing wind-turbine fatality data to model outputs could test many predictions, such as 'risk from turbines is highest in habitats between hoary bat summering and wintering grounds'. Although future field studies are needed to validate the SDMs, this study generated well-justified and testable hypotheses of hoary bat migration patterns and seasonal distribution.

  2. Seasonally-dynamic presence-only species distribution models for a cryptic migratory bat impacted by wind energy development

    USGS Publications Warehouse

    Hayes, Mark A.; Cryan, Paul M.; Wunder, Michael B.

    2015-01-01

    Understanding seasonal distribution and movement patterns of animals that migrate long distances is an essential part of monitoring and conserving their populations. Compared to migratory birds and other more conspicuous migrants, we know very little about the movement patterns of many migratory bats. Hoary bats (Lasiurus cinereus), a cryptic, wide-ranging, long-distance migrant, comprise a substantial proportion of the tens to hundreds of thousands of bat fatalities estimated to occur each year at wind turbines in North America. We created seasonally-dynamic species distribution models (SDMs) from 2,753 museum occurrence records collected over five decades in North America to better understand the seasonal geographic distributions of hoary bats. We used 5 SDM approaches: logistic regression, multivariate adaptive regression splines, boosted regression trees, random forest, and maximum entropy and consolidated outputs to generate ensemble maps. These maps represent the first formal hypotheses for sex- and season-specific hoary bat distributions. Our results suggest that North American hoary bats winter in regions with relatively long growing seasons where temperatures are moderated by proximity to oceans, and then move to the continental interior for the summer. SDMs suggested that hoary bats are most broadly distributed in autumn—the season when they are most susceptible to mortality from wind turbines; this season contains the greatest overlap between potentially suitable habitat and wind energy facilities. Comparing wind-turbine fatality data to model outputs could test many predictions, such as ‘risk from turbines is highest in habitats between hoary bat summering and wintering grounds’. Although future field studies are needed to validate the SDMs, this study generated well-justified and testable hypotheses of hoary bat migration patterns and seasonal distribution.

  3. Seasonally-Dynamic Presence-Only Species Distribution Models for a Cryptic Migratory Bat Impacted by Wind Energy Development

    PubMed Central

    Hayes, Mark A.; Cryan, Paul M.; Wunder, Michael B.

    2015-01-01

    Understanding seasonal distribution and movement patterns of animals that migrate long distances is an essential part of monitoring and conserving their populations. Compared to migratory birds and other more conspicuous migrants, we know very little about the movement patterns of many migratory bats. Hoary bats (Lasiurus cinereus), a cryptic, wide-ranging, long-distance migrant, comprise a substantial proportion of the tens to hundreds of thousands of bat fatalities estimated to occur each year at wind turbines in North America. We created seasonally-dynamic species distribution models (SDMs) from 2,753 museum occurrence records collected over five decades in North America to better understand the seasonal geographic distributions of hoary bats. We used 5 SDM approaches: logistic regression, multivariate adaptive regression splines, boosted regression trees, random forest, and maximum entropy and consolidated outputs to generate ensemble maps. These maps represent the first formal hypotheses for sex- and season-specific hoary bat distributions. Our results suggest that North American hoary bats winter in regions with relatively long growing seasons where temperatures are moderated by proximity to oceans, and then move to the continental interior for the summer. SDMs suggested that hoary bats are most broadly distributed in autumn—the season when they are most susceptible to mortality from wind turbines; this season contains the greatest overlap between potentially suitable habitat and wind energy facilities. Comparing wind-turbine fatality data to model outputs could test many predictions, such as ‘risk from turbines is highest in habitats between hoary bat summering and wintering grounds’. Although future field studies are needed to validate the SDMs, this study generated well-justified and testable hypotheses of hoary bat migration patterns and seasonal distribution. PMID:26208098

  4. Development of approximate method to analyze the characteristics of latent heat thermal energy storage system

    SciTech Connect

    Saitoh, T.S.; Hoshi, Akira

    1999-07-01

    Third Conference of the Parties to the U.N. Framework Convention on Climate Change (COP3) held in last December in Kyoto urged the industrialized nation to reduce carbon dioxide (CO{sub 2}) emissions by 5.2 percent (on the average) below 1990 level until the period between 2008 and 2012 (Kyoto protocol). This implies that even for the most advanced countries like the US, Japan, and EU implementation of drastic policies and overcoming many barriers in market should be necessary. One idea which leads to a path of low carbon intensity is to adopt an energy storage concept. One of the reasons that the efficiency of the conventional energy systems has been relatively low is ascribed to lacking of energy storage subsystem. Most of the past energy systems, for example, air-conditioning system, do not have energy storage part and the system usually operates with low energy efficiency. Firstly, the effect of reducing CO{sub 2} emissions was also examined if the LHTES subsystems were incorporated in all the residential and building air-conditioning systems. Another field of application of the LHTES is of course transportation. Future vehicle will be electric or hybrid vehicle. However, these vehicles will need considerable energy for air-conditioning. The LHTES system will provide enough energy for this purpose by storing nighttime electricity or rejected heat from the radiator or motor. Melting and solidification of phase change material (PCM) in a capsule is of practical importance in latent heat thermal energy storage (LHTES) systems which are considered to be very promising to reduce a peak demand of electricity in the summer season and also reduce carbon dioxide (CO{sub 2}) emissions. Two melting modes are involved in melting in capsules. One is close-contact melting between the solid bulk and the capsule wall, and another is natural convection melting in the liquid (melt) region. Close-contact melting processes for a single enclosure have been solved using several

  5. Home in the heat: dramatic seasonal variation in home range of desert golden eagles informs management for renewable energy development

    USGS Publications Warehouse

    Braham, Melissa; Miller, Tricia A.; Duerr, Adam E.; Lanzone, Michael; Fesnock, Amy; LaPre, Larry; Driscoll, Daniel; Katzner, Todd E.

    2015-01-01

    Renewable energy is expanding quickly with sometimes dramatic impacts to species and ecosystems. To understand the degree to which sensitive species may be impacted by renewable energy projects, it is informative to know how much space individuals use and how that space may overlap with planned development. We used global positioning system–global system for mobile communications (GPS-GSM) telemetry to measure year-round movements of golden eagles (Aquila chrysaetos) from the Mojave Desert of California, USA. We estimated monthly space use with adaptive local convex hulls to identify the temporal and spatial scales at which eagles may encounter renewable energy projects in the Desert Renewable Energy Conservation Plan area. Mean size of home ranges was lowest and least variable from November through January and greatest in February–March and May–August. These monthly home range patterns coincided with seasonal variation in breeding ecology, habitat associations, and temperature. The expanded home ranges in hot summer months included movements to cooler, prey-dense, mountainous areas characterized by forest, grasslands, and scrublands. Breeding-season home ranges (October–May) included more lowland semi-desert and rock vegetation. Overlap of eagle home ranges and focus areas for renewable energy development was greatest when eagle home ranges were smallest, during the breeding season. Golden eagles in the Mojave Desert used more space and a wider range of habitat types than expected and renewable energy projects could affect a larger section of the regional population than was previously thought.

  6. Seasonal variation of energy metabolism in ghost crab Ocypode quadrata at Siriú Beach (Brazil).

    PubMed

    Vinagre, Anapaula Sommer; Nunes do Amaral, Ana Paula; Ribarcki, Fabiana Pinto; Fraga da Silveira, Eliane; Périco, Eduardo

    2007-04-01

    The aim of this study was to analyze the seasonal variations of carbohydrate and lipid metabolism of the ghost crab Ocypode quadrata (Fabricius, 1787) on a sandy beach in the southern region of Brazil. Crabs and hemolymph samples were collected monthly in the field. Hepatopancreas, gills, gonads and claw muscles were used for glycogen determination. In males, blood glucose levels increased in the summer and in the winter. The glycogen values increased significantly in the hepatopancreas in the winter, but remained constant in the muscle, gonads and gills. In females, hemolymph glucose levels, glycogen values in the hepatopancreas and in the gills remained constant throughout the year; however, muscular glycogen increased in the spring and gonad glycogen decreased in the summer. Hemolymph triglyceride levels of males and females and total cholesterol of males decreased significantly in the spring. In females, a significant increase of total cholesterol levels was found in the winter. The findings suggest that in O. quadrata lipids seem to be an important reserve of energy used during reproduction, both in males and females, while glycogen may be used during periods of intense activity or fasting.

  7. Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

    NASA Technical Reports Server (NTRS)

    Ferarra, A.; Yenetchi, G.; Haslett, R.; Kosson, R.

    1977-01-01

    Sizing procedures are presented for latent heat thermal energy storage systems that can be used for electric utility off-peak energy storage, solar power plants and other preliminary design applications.

  8. Relationship of regional water quality to aquifer thermal energy storage

    SciTech Connect

    Allen, R.D.

    1983-11-01

    Ground-water quality and associated geologic characteristics may affect the feasibility of aquifer thermal energy storage (ATES) system development in any hydrologic region. This study sought to determine the relationship between ground-water quality parameters and the regional potential for ATES system development. Information was collected from available literature to identify chemical and physical mechanisms that could adversely affect an ATES system. Appropriate beneficiation techniques to counter these potential geochemical and lithologic problems were also identified through the literature search. Regional hydrology summaries and other sources were used in reviewing aquifers of 19 drainage regions in the US to determine generic geochemical characteristics for analysis. Numerical modeling techniques were used to perform geochemical analyses of water quality from 67 selected aquifers. Candidate water resources regions were then identified for exploration and development of ATES. This study identified six principal mechanisms by which ATES reservoir permeability may be impaired: (1) particulate plugging, (2) chemical precipitation, (3) liquid-solid reactions, (4) formation disaggregation, (5) oxidation reactions, and (6) biological activity. Specific proven countermeasures to reduce or eliminate these effects were found. Of the hydrologic regions reviewed, 10 were identified as having the characteristics necessary for ATES development: (1) Mid-Atlantic, (2) South-Atlantic Gulf, (3) Ohio, (4) Upper Mississippi, (5) Lower Mississippi, (6) Souris-Red-Rainy, (7) Missouri Basin, (8) Arkansas-White-Red, (9) Texas-Gulf, and (10) California.

  9. Ocean Thermal Energy Conversion (OTEC) Programmatic Environmental Analysis--Appendices

    SciTech Connect

    Authors, Various

    1980-01-01

    The programmatic environmental analysis is an initial assessment of Ocean Thermal Energy Conversion (OTEC) technology considering development, demonstration and commercialization. It is concluded that the OTEC development program should continue because the development, demonstration, and commercialization on a single-plant deployment basis should not present significant environmental impacts. However, several areas within the OTEC program require further investigation in order to assess the potential for environmental impacts from OTEC operation, particularly in large-scale deployments and in defining alternatives to closed-cycle biofouling control: (1) Larger-scale deployments of OTEC clusters or parks require further investigations in order to assess optimal platform siting distances necessary to minimize adverse environmental impacts. (2) The deployment and operation of the preoperational platform (OTEC-1) and future demonstration platforms must be carefully monitored to refine environmental assessment predictions, and to provide design modifications which may mitigate or reduce environmental impacts for larger-scale operations. These platforms will provide a valuable opportunity to fully evaluate the intake and discharge configurations, biofouling control methods, and both short-term and long-term environmental effects associated with platform operations. (3) Successful development of OTEC technology to use the maximal resource capabilities and to minimize environmental effects will require a concerted environmental management program, encompassing many different disciplines and environmental specialties. This volume contains these appendices: Appendix A -- Deployment Scenario; Appendix B -- OTEC Regional Characterization; and Appendix C -- Impact and Related Calculations.

  10. Draft environmental assessment: Ocean Thermal Energy Conversion (OTEC) Pilot Plants

    SciTech Connect

    Sullivan, S.M.; Sands, M.D.; Donat, J.R.; Jepsen, P.; Smookler, M.; Villa, J.F.

    1981-02-01

    This Environmental Assessment (EA) has been prepared, in accordance with the National Environmental Policy Act of 1969, for the deployment and operation of a commercial 40-Megawatt (MW) Ocean Thermal Energy Conversion (OTEC) Pilot Plant (hereafter called the Pilot Plant). A description of the proposed action is presented, and a generic environment typical of the candidate Pilot Plant siting regions is described. An assessment of the potential environmental impacts associated with the proposed action is given, and the risk of credible accidents and mitigating measures to reduce these risks are considered. The Federal and State plans and policies the proposed action will encompass are described. Alternatives to the proposed action are presented. Appendix A presents the navigation and environmental information contained in the US Coast Pilot for each of the candidate sites; Appendix B provides a brief description of the methods and calculations used in the EA. It is concluded that environmental disturbances associated with Pilot Plant activities could potentially cause significant environmental impacts; however, the magnitude of these potential impacts cannot presently be assessed, due to insufficient engineering and environmental information. A site- and design-specific OTEC Pilot Plant Environmental Impact Statement (EIS) is required to resolve the potentially significant environmental effects associated with Pilot Plant deployment and operation. (WHK)

  11. Production of desalinated water using ocean thermal energy

    NASA Astrophysics Data System (ADS)

    Rabas, T.; Panchal, C.

    This paper describes an Ocean Thermal Energy Conversion (OTEC) desalination plant that consists of a multistage flash evaporator (MSF), a closed-cycle OTEC power plant, and an appropriate seawater system depending if the desalination plant is land based or floating. OTEC desalination plants of this type are preferred because the production of desalinated water far exceeds that obtained from other OTEC plant types employing the same size seawater system. The focus of the paper is on the multistage flash evaporator. The similarities and differences between conventional MSF and OTEC multistage flash evaporators (OTEC-MSF) are first described. Then the details of the OTEC-MSF evaporator design are discussed and preliminary correlations are recommended for the three major elements: the flash chamber, the moisture removal device, and the condenser. Recent advances such as enhanced condenser tubes, condensers of the compact type, and corrugated-plate moisture separators are introduced into the design. Comparisons of the water production capability, evaporator shell volume, and material cost are then presented for state-of-the-art and the new design concepts.

  12. Production of desalinated water using ocean thermal energy

    SciTech Connect

    Rabas, T.; Panchal, C.

    1991-01-01

    This paper describes an Ocean Thermal Energy Conversion (OTEC) desalination plant that consists of a multistage flash evaporator (MSF), a closed-cycle OTEC power plant, and an appropriate seawater system depending if the desalination plant is land based or floating. OTEC desalination plants of this type are preferred because the production of desalinated water far exceeds that obtained from other OTEC plant types employing the same size seawater system. The focus of the paper is on the multistage flash evaporator. The similarities and differences between conventional MSF and OTEC multistage flash evaporators (OTEC-MSF) are first described. Then the details of the OTEC-MSF evaporator design are discussed and preliminary correlations are recommended for the three major elements: the flash chamber, the moisture removal device, and the condenser. Recent advances such as enhanced condenser tubes, condensers of the compact type, and corrugated-plate moisture separators are introduced into the design. Comparisons of the water production capability, evaporator shell volume, and material cost are then presented for state-of-the-art and the new design concepts. 20 refs., 11 figs., 5 tabs.

  13. Calibration of sonic flowmeters for Ocean Thermal Energy Conversion (OTEC)

    NASA Astrophysics Data System (ADS)

    Lott, D. F.; Salsman, G. G.; Hodges, C. E.

    1980-12-01

    Scientists at the Naval Coastal Systems Center (NCSC) at Panama City, Florida, have used a commercially available acoustic flowmeter to monitor critical flow conditions during an OTEC (Ocean Thermal Energy Conversion) funded study of the effects of biofouling on the efficiency of a prototype heat transfer system. Flowmeters of this type are particularly useful in applications requiring unimpeded flow; i.e., no sensor projecting into the moving fluid. Unfortunately, sonic flowmeters are somewhat difficult to calibrate and may be subject to drift. A method of calibration devised by NCSC may thus be of some interest to other users. It is the purpose of this report to document the special procedures used by test personnel to calibrate the flowmeters. Briefly, the calibration consisted of pumping sea water through the flowmeter into a tank suspended beneath a special load cell which provided an output voltage proportional to the weight of water in the tank. A programmable desktop calculator system was used to monitor changes in voltage as a function of time and convert these changes into flow rates for direct comparison with values read from the sonic flowmeter's digital display. Calibration checks were made at metered flows of 8, 10, 12, 14, 16, and 18 gallons per minute (gpm). It was found that computed flows were essentially linear but differed from metered values by as much as 9.0 percent.

  14. Population level differences in thermal sensitivity of energy assimilation in terrestrial salamanders.

    PubMed

    Clay, Timothy A; Gifford, Matthew E

    2017-02-01

    Thermal adaptation predicts that thermal sensitivity of physiological traits should be optimized to thermal conditions most frequently experienced. Furthermore, thermodynamic constraints predict that species with higher thermal optima should have higher performance maxima and narrower performance breadths. We tested these predictions by examining the thermal sensitivity of energy assimilation between populations within two species of terrestrial-lungless salamanders, Plethodon albagula and P. montanus. Within P. albagula, we examined populations that were latitudinally separated by >450km. Within P. montanus, we examined populations that were elevationally separated by >900m. Thermal sensitivity of energy assimilation varied substantially between populations of P. albagula separated latitudinally, but did not vary between populations of P. montanus separated elevationally. Specifically, in P. albagula, the lower latitude population had a higher thermal optimum, higher maximal performance, and narrower performance breadth compared to the higher latitude population. Furthermore, across all individuals as thermal optima increased, performance maxima also increased, providing support for the theory that "hotter is better".

  15. Research and Development for Novel Thermal Energy Storage Systems (TES) for Concentrating Solar Power (CSP)

    SciTech Connect

    Faghri, Amir; Bergman, Theodore L; Pitchumani, Ranga

    2013-09-26

    The overall objective was to develop innovative heat transfer devices and methodologies for novel thermal energy storage systems for concentrating solar power generation involving phase change materials (PCMs). Specific objectives included embedding thermosyphons and/or heat pipes (TS/HPs) within appropriate phase change materials to significantly reduce thermal resistances within the thermal energy storage system of a large-scale concentrating solar power plant and, in turn, improve performance of the plant. Experimental, system level and detailed comprehensive modeling approaches were taken to investigate the effect of adding TS/HPs on the performance of latent heat thermal energy storage (LHTES) systems.

  16. Phase change material in floor tiles for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Lee, Amy Sarah

    Traditional passive solar systems have relied on sensible heat storage for energy savings. Recent research has investigated taking advantage of latent heat storage for additional energy savings. This is accomplished by the incorporation of phase change material into building materials used in traditional passive applications. Trombe walls, ceilings and floors can all be enhanced with phase change materials. This research introduces a new flooring material that incorporates a phase change material ready for commercial manufacture. An agglomerate floor tile containing 20% by mass of encapsulated octadecane has been manufactured. Flexural and compressive strength of 7.4 MPa and 24.5 MPa respectively, were measured for the tile. Peak melting transition temperature was determined to be 27.2°C with a latent heat of 33.9 J/g of tile. Structural and thermal performance of the tile surpassed that of a typical ceramic tile. Each tile was composed of quartz, resin and phase change material. Statistical modeling was performed to analyze the response of flexural and compressive strength on varying amounts of quartz, resin and phase change material. Resulting polynomials described the effect of adding phase change material into the tile. With as little as 10% by mass of phase change material, the strength was reduced to less than 50% of tile without phase change material. It was determined that the maximum phase change material content to attain structural integrity greater than ceramic tile was 20% by mass. The statistical analysis used for this research was based on mixture experiments. A procedure was developed to simplify the selection of data points used in the fit of the polynomials to describe the response of flexural and compressive strengths. Analysis of energy savings using this floor tile containing 20% by mass of phase change material was performed as an addendum to this research. A known static simulation method, SLR (solar load ratio), was adapted to include

  17. Seasonal changes in body mass, energy intake and thermogenesis in Maximowiczi's voles (Microtus maximowiczii) from the Inner Mongolian grassland.

    PubMed

    Chen, Jing-Feng; Zhong, Wen-Qin; Wang, De-Hua

    2012-02-01

    Small mammals inhabiting temperate and arctic regions exhibit annual adaptive adjustments in physiology, anatomy, and behavior. No data on the physiology of Maximowicz's voles (Microtus maximowiczii) are available at present. Here we examined the seasonal changes in body mass, food intake, thermogenic capacity, serum leptin and thyroid hormone levels in wild-captured individuals from Inner Mongolian grassland, China. We further examined the effects of photoperiod on these parameters. Energy intake, resting metabolic rate, nonshivering thermogenesis (NST), and serum tri-iodothyronine (T3) levels increased while serum leptin and body mass decreased in the cold seasons. Serum T3 levels were positively correlated with NST and uncoupling protein 1 (UCP1) contents in brown adipose tissue, and leptin levels were negatively correlated with energy intake and resting metabolic rate. Furthermore, laboratory data showed these changes could be induced by short photoperiod alone. Taken together, our results indicate that Maximowicz's voles can increase thermogenic capacity and energy intake to cope with cold stress. Serum leptin seems to be involved in the regulation of energy intake and changes in T3 level may be important for the variations in NST and/or UCP1. Short photoperiod can serve as a seasonal cue for the winter acclimatization of energy balance in free-living Maximowicz's voles.

  18. Seasonal Evolution and Interannual Variability of the Local Solar Energy Absorbed by the Arctic Sea Ice-Ocean System

    NASA Technical Reports Server (NTRS)

    Perovich, Donald K.; Nghiem, Son V.; Markus, Thorsten; Schwieger, Axel

    2007-01-01

    The melt season of the Arctic sea ice cover is greatly affected by the partitioning of the incident solar radiation between reflection to the atmosphere and absorption in the ice and ocean. This partitioning exhibits a strong seasonal cycle and significant interannual variability. Data in the period 1998, 2000-2004 were analyzed in this study. Observations made during the 1997-1998 SHEBA (Surface HEat Budget of the Arctic Ocean) field experiment showed a strong seasonal dependence of the partitioning, dominated by a five-phase albedo evolution. QuikSCAT scatterometer data from the SHEBA region in 1999-2004 were used to further investigate solar partitioning in summer. The time series of scatterometer data were used to determine the onset of melt and the beginning of freezeup. This information was combined with SSM/I-derived ice concentration, TOVS-based estimates of incident solar irradiance, and SHEBA results to estimate the amount of solar energy absorbed in the ice-ocean system for these years. The average total solar energy absorbed in the ice-ocean system from April through September was 900 MJ m(sup -2). There was considerable interannual variability, with a range of 826 to 1044 MJ m(sup -2). The total amount of solar energy absorbed by the ice and ocean was strongly related to the date of melt onset, but only weakly related to the total duration of the melt season or the onset of freezeup. The timing of melt onset is significant because the incident solar energy is large and a change at this time propagates through the entire melt season, affecting the albedo every day throughout melt and freezeup.

  19. Experimental simulation of latent heat thermal energy storage and heat pipe thermal transport for dish concentrator solar receiver

    NASA Technical Reports Server (NTRS)

    Narayanan, R.; Zimmerman, W. F.; Poon, P. T. Y.

    1981-01-01

    Test results on a modular simulation of the thermal transport and heat storage characteristics of a heat pipe solar receiver (HPSR) with thermal energy storage (TES) are presented. The HPSR features a 15-25 kWe Stirling engine power conversion system at the focal point of a parabolic dish concentrator operating at 827 C. The system collects and retrieves solar heat with sodium pipes and stores the heat in NaF-MgF2 latent heat storage material. The trials were run with a single full scale heat pipe, three full scale TES containers, and an air-cooled heat extraction coil to replace the Stirling engine heat exchanger. Charging and discharging, constant temperature operation, mixed mode operation, thermal inertial, etc. were studied. The heat pipe performance was verified, as were the thermal energy storage and discharge rates and isothermal discharges.

  20. Surface Energy Exchange in a Tropical Montane Cloud Forest Environment: Flux Partitioning, and Seasonal and Land Cover-Related Variations

    NASA Astrophysics Data System (ADS)

    Holwerda, F.; Alvarado-Barrientos, M. S.; González-Martínez, T.

    2015-12-01

    Relationships between seasonal climate, land cover and surface energy exchange in tropical montane cloud forest (TMCF) environments are poorly understood. Yet, understanding these linkages is essential to evaluating the impacts of land use and climate change on the functioning of these unique ecosystems. In central Veracruz, Mexico, TMCF occurs between 1100 and 2500 m asl. The canopy of this forest consists of a mix of deciduous and broadleaved-evergreen tree species, the former of which shed their leaves for a short period during the dry season. The aim of this study was to quantify the surface energy balance, and seasonal variations therein, for TMCF, as well as for shaded coffee (CO) and sugarcane (SU), two important land uses that have replaced TMCF at lower elevations. Sensible (H) and latent heat (LE) fluxes were measured using eddy covariance and sap flow methods. Other measurements included: micrometeorological variables, soil heat flux, soil moisture and vegetation characteristics. Partitioning of available energy (A) into H and LE showed important seasonal changes as well as differences among land covers. During the wet-season month of July, average midday Bowen ratios for sunny days were lowest and least variable among land covers: 0.5 in TMCF and SU versus 0.7 in CO. However, because of higher A, along with lower Bowen ratio with respect to CO, LE over TMCF was ca. 20% higher compared to CO and SU. During the late dry-season months of March and April, average midday Bowen ratios for sunny days were generally much higher and more variable among land covers. The higher Bowen ratios indicated a reduction of LE under the drier conditions prevailing (low soil moisture and high VPD), something rarely observed in TMCFs. Moreover, because some trees were still partially leafless in March, LE over TMCF was about half that over CO and SU, suggesting an important effect of phenology on energy exchange of this TMCF. Observed differences between seasons and land

  1. Seasonal to interannual morphodynamics along a high-energy dissipative littoral cell

    USGS Publications Warehouse

    Ruggiero, P.; Kaminsky, G.M.; Gelfenbaum, G.; Voigt, B.

    2005-01-01

    A beach morphology monitoring program was initiated during summer 1997 along the Columbia River littoral cell (CRLC) on the coasts of northwest Oregon and southwest Washington, USA. This field program documents the seasonal through interannual morphological variability of these high-energy dissipative beaches over a variety of spatial scales. Following the installation of a dense network of geodetic control monuments, a nested sampling scheme consisting of cross-shore topographic beach profiles, three-dimensional topographic beach surface maps, nearshore bathymetric surveys, and sediment size distribution analyses was initiated. Beach monitoring is being conducted with state-of-the-art real-time kinematic differential global positioning system survey methods that combine both high accuracy and speed of measurement. Sampling methods resolve variability in beach morphology at alongshore length scales of approximately 10 meters to approximately 100 kilometers and cross-shore length scales of approximately 1 meter to approximately 2 kilometers. During the winter of 1997/1998, coastal change in the US Pacific Northwest was greatly influenced by one of the strongest El Nin??o events on record. Steeper than typical southerly wave angles resulted in alongshore sediment transport gradients and shoreline reorientation on a regional scale. The La Nin??a of 1998/1999, dominated by cross-shore processes associated with the largest recorded wave year in the region, resulted in net beach erosion along much of the littoral cell. The monitoring program successfully documented the morphological response to these interannual forcing anomalies as well as the subsequent beach recovery associated with three consecutive moderate wave years. These morphological observations within the CRLC can be generalized to explain overall system patterns; however, distinct differences in large-scale coastal behavior (e.g., foredune ridge morphology, sandbar morphometrics, and nearshore beach slopes

  2. Climatic warming above the Arctic Circle: are there trends in timing and length of the thermal growing season in Murmansk Region (Russia) between 1951 and 2012?

    NASA Astrophysics Data System (ADS)

    Blinova, Ilona; Chmielewski, Frank-Michael

    2015-06-01

    Anomalies in the timing of the thermal growing season have become obvious in the NE part of Fennoscandia since 2000. They are in accordance with climatic changes reported for Europe and Fennoscandia. The actual length of the growing season reached 120 days on average, onset on 30 May and ending on 27 September (1981-2010). Shifts in the timing of the growing season and its mean prolongation by 18.5 days/62a are demonstrated for Murmansk Region (1951-2012). In this period, the onset of the growing season advanced by 7.1 days/62a, while the end was extended by 11.4 days/62a. The delay in the end of the growing season is similar to the entire Fennoscandian pattern but it has not been detected in the rest of Europe. The regional pattern of climatic regimes in Murmansk Region remained stable in comparison with earlier climatic maps (1971). However, the actual shifts in the timing of the growing season were more pronounced in colder (oceanic and mountainous) parts. Recent climatic trends could influence the retreat of the tundra zone and changes in the forest line. Losses of tundra biodiversity and enrichment of the northern taiga by southern species could be expected from present climatic trends.

  3. Optimal Deployment of Thermal Energy Storage under Diverse Economic and Climate Conditions

    SciTech Connect

    DeForest, Nicolas; Mendes, Goncalo; Stadler, Michael; Feng, Wei; Lai, Judy; Marnay, Chris

    2014-04-15

    This paper presents an investigation of the economic benefit of thermal energy storage (TES) for cooling, across a range of economic and climate conditions. Chilled water TES systems are simulated for a large office building in four distinct locations, Miami in the U.S.; Lisbon, Portugal; Shanghai, China; and Mumbai, India. Optimal system size and operating schedules are determined using the optimization model DER-CAM, such that total cost, including electricity and amortized capital costs are minimized. The economic impacts of each optimized TES system is then compared to systems sized using a simple heuristic method, which bases system size as fraction (50percent and 100percent) of total on-peak summer cooling loads. Results indicate that TES systems of all sizes can be effective in reducing annual electricity costs (5percent-15percent) and peak electricity consumption (13percent-33percent). The investigation also indentifies a number of criteria which drive TES investment, including low capital costs, electricity tariffs with high power demand charges and prolonged cooling seasons. In locations where these drivers clearly exist, the heuristically sized systems capture much of the value of optimally sized systems; between 60percent and 100percent in terms of net present value. However, in instances where these drivers are less pronounced, the heuristic tends to oversize systems, and optimization becomes crucial to ensure economically beneficial deployment of TES, increasing the net present value of heuristically sized systems by as much as 10 times in some instances.

  4. Seasonal variations of the energy metabolism of two sympatric species of Hyalella (Crustacea, Amphipoda, Dogielinotidae) in the southern Brazilian highlands.

    PubMed

    Dutra, B K; Castiglioni, D S; Santos, R B; Bond-Buckup, G; Oliveira, G T

    2007-09-01

    Aquatic organisms exist in a constantly fluctuating habitat, with changes in photoperiod, temperature, pH, dissolved organic content, dissolved oxygen and food supply. Organisms must alter past of their physiological and biochemical processes to cope with these changes. We compared the effect of seasonal variations in factors related to energy metabolism of two species of sympatric amphipods, Hyalella pleoacuta and Hyalella castroi. The animals were collected monthly from April 2004 through March 2006. Contents of glycogen, proteins, lipids, triglycerides and the levels of lipoperoxidation were determined in males and females throughout the year by using spectrophotometric methods. Observations revealed significant seasonal differences in biochemical composition, as well as differences among sexes and species. Environmental conditions (e.g., trophic conditions) and reproduction are supposed to be the main processes influencing the seasonal patterns of variation in biochemical composition. Both species of Hyalella show ecological and behavioral differences, especially by resources such as food, space and seasonal variations of energy metabolism, which might facilitate their coexistence in the same habitat.

  5. Particulate concentrations during on-farm combustion of energy crops of different shapes and harvest seasons

    NASA Astrophysics Data System (ADS)

    Fournel, S.; Palacios, J. H.; Morissette, R.; Villeneuve, J.; Godbout, S.; Heitz, M.; Savoie, P.

    2015-03-01

    The increasing energy costs and environmental concerns of farms have motivated the growing interest of agricultural producers in using farm-grown biomass as a substitute to fossil fuels for heat production. However, the use of non-woody biomass is facing challenges due to variability regarding chemical composition and fuel properties that may induce problems during combustion such as particulate matter (PM). The aim of this work was to measure and compare total PM concentrations during on-farm combustion of wood and four agricultural crops: short-rotation willow, switchgrass, miscanthus and reed canary grass. In order to study the influence of physicochemical properties, different shapes (pellets, chips and chopped grasses) and harvest seasons (fall and spring) were also evaluated. In this context, a representative small-scale (29 kW), multi-fuel boiler for light commercial use was utilized. The boiler was also non-catalytic so that the burning took place in a single combustion chamber. Overall, twelve different biomass fuels were tested and each product was burned three times. Mean PM concentration of wood (416 mg Nm-3 at 7 vol% O2) was lower than that of the four dedicated energy crops (505-1417 mg Nm-3 at 7 vol% O2). However, because of the high variability between the experiments, no statistical significance was observed at P > 0.1 level except in one case. The PM amounts were high compared to literature data and Quebec's environmental regulation mainly because of the boiler system used. Except for willow, pelletized products decreased PM levels by 22-52% compared to chopped materials. Bulky biomass of low density was unable to reach steady-state conditions and produced compounds associated with incomplete combustion including PM. Spring-harvested biomass fuels showed a PM reduction up to 48% compared to fall-harvested crops. This was likely due to a 20-60% decrease of several chemical elements in the biomass, namely S, Cl, K and P which are the main

  6. Advanced Thermal Energy Conversion of Temperature under 300°C by Thermoelectric Conversion Method

    NASA Astrophysics Data System (ADS)

    Ueda, Tadashi; Uchida, Yoshiyuki; Shingu, Hiroyasu

    Many approaches have been developing for energy conversion throughout the world. However, it is difficult to achieve the global warming countermeasure based on “The Kyoto protocol”. Until now effective utilization of low temperature thermal energy (under 300°C) is not advancing one. For example, effective utilization method has not been established for waste heat energy which arise from industry machine tools, automobiles, internal combustion engines and thermal energy from natural environment, etc. In this paper, we reported the experiment for effective utilizing of low temperature (under 300°C) thermal energy conversion. The device used for the measurement is a copper thermo device. Thermo electromotive force of 150mW/cm2 was obtained at 200°C. The obtained thermo electromotive force is about 15 times higher in comparison with generally used alumal-chromal thermocouple. Our aim is that utilizes low temperature thermal energy effectively by converting into electricity.

  7. Program definition and assessment overview. [for thermal energy storage project management

    NASA Technical Reports Server (NTRS)

    Gordon, L. H.

    1980-01-01

    The implementation of a program level assessment of thermal energy storage technology thrusts for the near and far term to assure overall coherent energy storage program is considered. The identification and definition of potential thermal energy storage applications, definition of technology requirements, and appropriate market sectors are discussed along with the necessary coordination, planning, and preparation associated with program reviews, workshops, multi-year plans and annual operating plans for the major laboratory tasks.

  8. Control Strategy: Wind Energy Powered Variable Chiller with Thermal Ice Storage

    DTIC Science & Technology

    2014-12-01

    thermal storage system for other uses such as heating , 4. Reconfigure the micro-grid for optimal performance and energy storage after all...of Naval Operations, Technical Monitor: Stacey Cmtis, Space and Naval AGENCY REPORT NUMBER Watfare Systems Command, (ESTEP) Energy Systems ...chiller system powered by renewable energy with ice thermal storage . A control strategy was also developed that matched the chiller load to any

  9. High temperature thermal energy storage, including a discussion of TES integrated into power plants

    NASA Technical Reports Server (NTRS)

    Turner, R. H.

    1978-01-01

    Storage temperatures of 260 C and above are considered. Basic considerations concerning energy thermal storage are discussed, taking into account general aspects of thermal energy storage, thermal energy storage integrated into power plants, thermal storage techniques and technical considerations, and economic considerations. A description of system concepts is provided, giving attention to a survey of proposed concepts, storage in unpressurized fluids, water storage in pressurized containers, the use of an underground lined cavern for water storage, a submerged thin insulated steel shell under the ocean containing pressurized water, gas passage through solid blocks, a rock bed with liquid heat transport fluid, hollow steel ingots, heat storage in concrete or sand, sand in a fluidized bed, sand poured over pipes, a thermal energy storage heat exchanger, pipes or spheres filled with phase change materials (PCM), macroencapsulated PCM with heat pipe concept for transport fluid, solid PCM removed from heat transfer pipes by moving scrapers, and the direct contact between PCM and transport fluid.

  10. Advances in Thermal Spray Coatings for Gas Turbines and Energy Generation: A Review

    NASA Astrophysics Data System (ADS)

    Hardwicke, Canan U.; Lau, Yuk-Chiu

    2013-06-01

    Functional coatings are widely used in energy generation equipment in industries such as renewables, oil and gas, propulsion engines, and gas turbines. Intelligent thermal spray processing is vital in many of these areas for efficient manufacturing. Advanced thermal spray coating applications include thermal management, wear, oxidation, corrosion resistance, sealing systems, vibration and sound absorbance, and component repair. This paper reviews the current status of materials, equipment, processing, and properties' aspects for key coatings in the energy industry, especially the developments in large-scale gas turbines. In addition to the most recent industrial advances in thermal spray technologies, future technical needs are also highlighted.

  11. Design and development of integral heat pipe/thermal energy storage devices. [used with spacecraft cryocoolers

    NASA Technical Reports Server (NTRS)

    Mahefkey, E. T.; Richter, R.

    1981-01-01

    The major design and performance test subtasks in the development of small (200 to 1,000 whr) integral heat pipe/thermal energy storage devices for use with thermally driven spacecraft cryo-coolers are described. The design of the integral heat pipe/thermal energy storage device was based on a quasi steady resistance heat transfer, lumped capacitance model. Design considerations for the heat pipe and thermal storage annuli are presented. The thermomechanical stress and insulation system design for the device are reviewed. Experimental correlations are described, as are the plans for the further development of the concept.

  12. Characterization of high rate composting of vegetable market waste using Fourier transform-infrared (FT-IR) and thermal studies in three different seasons.

    PubMed

    Ali, Muntjeer; Bhatia, Akansha; Kazmi, A A; Ahmed, Naseem

    2012-04-01

    Fourier transform-infrared (FT-IR), Thermogravimetry (TG), Differential thermal analyses (DTA) and Differential Thermogravimetric (DTG) studies of a mixture of vegetable waste, saw dust, tree leaves and cow dung for microbial activity (feedstock) and their compost were reported in three different seasons i.e. winter, spring and summer. The correlation between spectral studies and compost composition provide information regarding their stability and maturity during composting. FT-IR spectra were conferred the functional groups and their intensity and TG, DTG and DTA for wt. loss, rate of wt. loss and enthalpy change in compost. Weight loss in feedstock and compost at two different temperatures 250-350 and 350-500°C was found 38.06, 28.15% for inlet and 14.08, 25.67% for outlet zones in summer and 50.59, 29.76% for inlet and 18.08, 25.67% in outlet zones in spring season, higher (5-10%) than winter. The corresponding temperatures in DTA in the samples from inlet to outlet zone were; endotherm (100-200°C), due to dehydration, exotherm (300-320°C), due to peptidic structure loss and exotherm (449-474°C) due to the loss of polynuclear aromatic structures, which were higher by 4°C and 10-20°C and rate of wt. loss was higher by 5-10% in spring and summer season, respectively than winter season composting, reported regardless of the maturation age of the compost. Relative intensity of exotherms (300-320/449-474°C) gave the thermally more stable fractions of organic compound. Our results indicated that the rotary drum composting of organic matters in spring and summer season gave higher molecular complexity and stability than the winter season.

  13. Thermal energy effects on articular cartilage: a multidisciplinary evaluation

    NASA Astrophysics Data System (ADS)

    Kaplan, Lee D.; Ernsthausen, John; Ionescu, Dan S.; Studer, Rebecca K.; Bradley, James P.; Chu, Constance R.; Fu, Freddie H.; Farkas, Daniel L.

    2002-05-01

    Partial thickness articular cartilage lesions are commonly encountered in orthopedic surgery. These lesions do not have the ability to heal by themselves, due to lack of vascular supply. Several types of treatment have addressed this problem, including mechanical debridement and thermal chondroplasty. The goal of these treatments is to provide a smooth cartilage surface and prevent propagation of the lesions. Early thermal chondroplasty was performed using lasers, and yielded very mixed results, including severe damage to the cartilage, due to poor control of the induced thermal effects. This led to the development (including commercial) of probes using radiofrequency to generate the thermal effects desired for chondroplasty. Similar concerns over the quantitative aspects and control ability of the induced thermal effects in these treatments led us to test the whole range of complex issues and parameters involved. Our investigations are designed to simultaneously evaluate clinical conditions, instrument variables for existing radiofrequency probes (pressure, speed, distance, dose) as well as the associated basic science issues such as damage temperature and controllability (down to the subcellular level), damage geometry, and effects of surrounding conditions (medium, temperature, flow, pressure). The overall goals of this work are (1) to establish whether thermal chondroplasty can be used in a safe and efficacious manner, and (2) provide a prescription for multi-variable optimization of the way treatments are delivered, based on quantitative analysis. The methods used form an interdisciplinary set, to include precise mechanical actuation, high accuracy temperature and temperature gradient control and measurement, advanced imaging approaches and mathematical modeling.

  14. Seasonal snow cover and glacier change impact on water and energy cycle of Central Asia Endorheic Basin

    NASA Astrophysics Data System (ADS)

    Eisen, Vladimir; Eisen, Elena

    2010-05-01

    High mountains of Central Asia Endorheic Basin (CAEB) hold one of the greatest in the World concentration of snow and glacier ice water resources at mid- latitudes thousands of miles from the oceans providing up to 80% of total river runoff. The total external atmospheric moisture flow over the CAEB comprises approximately 200 billion cubic meters per year. The glaciers of CAEB receive and retain annually up to 10% of moisture transferred over the mountains. However, the area of seasonal snow and glaciers has declining rapidly as result of recent climatic change causes by increase in air temperature and precipitation partitioning between snow and rain, and evaporation fluxes. Based on remote sensing data CAEB glaciers shrunk by 5% between the middle of 1940th and 1970th and 10% during the next 30 years. Evaluation of seasonal snow cover for the same period revealed 20% seasonal snow covered area reduction. During the last thirty years, the duration of snow melt reduced by 30 days from the date of maximum snow cover to the date of its disappearance. Further decrease in seasonal snow cover will be accelerated due to increase of rainfall instead of snowfall in early spring months at high elevations, and consequently a lesser heat expenditure for snowmelt. At high mountains, about 40% of snow ablated during the penultimate 10 days of snow cover. During ablation season, the amount of energy used to melt snow and glacier ice is in the same order as the combination of other components of the heat budget (e.g., heat associated with atmospheric advection, radiation balance and turbulent heat exchange). Heating of the air would have been 3 times higher if snow and glacier ice melt had not occurred. Analysis of shallow ice-cores from high elevation snow/ice fields of CAEB has helped determining the climatic processes controlling hydrological regimes via the changes in global and regional atmospheric circulation patterns and simulates impact of these changes on water and

  15. Calibration of seasonal forecasts over Euro-Mediterranean region: improve climate information for the applications in the energy sector

    NASA Astrophysics Data System (ADS)

    De Felice, Matteo; Alessandri, Andrea; Catalano, Franco

    2013-04-01

    Accurate and reliable climate information, calibrated for the specific geographic domain, are critical for an effective planning of operations in industrial sectors, and more in general, for all the human activities. The connection between climate and energy sector became particularly evident in the last decade, due to the diffusion of renewable energy sources and the consequent attention on the socio-economical effects of extreme climate events .The energy sector needs reliable climate information in order to plan effectively power plants operations and forecast energy demand and renewable output. On time-scales longer than two weeks (seasonal), it is of critical importance the optimization of global climate information on the local domains needed by specific applications. An application that is distinctly linked with climate is electricity demand forecast, in fact, especially during cold/hot periods, the electricity usage patterns are influenced by the use of electric heating/cooling equipments which diffusion is steadily increasing worldwide [McNeil & Letschert, 2007]. Following an approach similar to [Navarra & Tribbia, 2005], we find a linear relationship between seasonal forecasts main modes of temperature anomaly and the main modes of reanalysis on Euro-Mediterranean domain. Then, seasonal forecasts are calibrated by means of a cross-validation procedure with the aim of optimize climate information over Italy. Calibrated seasonal forecasts are used as predictor for electricity demand forecast on Italy during the summer (JJA) in the period 1990-2009. Finally, a comparison with the results obtained with not calibrated climate forecasts is performed. The proposed calibration procedure led to an improvements of electricity demand forecast performance with more evident effects on the North of Italy, reducing the overall RMSE of 10% (from 1.09 to 0.98). Furthermore, main principal components are visualized and put in relation with electricity demand patterns in

  16. Design and Fabrication of Photonic Crystals for Thermal Energy Conservation

    SciTech Connect

    Professor John Joannopoulos; Professor Yoel Fink

    2009-09-17

    The vision of intelligent and large-area fabrics capable of signal processing, sensing and energy harvesting has made incorporating electronic devices into flexible fibers an active area of research. Fiber-integrated rectifying junctions in the form of photovoltaic cells and light-emitting diodes (LEDs) have been fabricated on optical fiber substrates. However, the length of these fiber devices has been limited by the processing methods and the lack of a sufficiently conductive and transparent electrode. Their cylindrical device geometry is ideal for single device architectures, like photovoltaics and LEDs, but not amenable to building multiple devices into a single fiber. In contrast, the composite preform-to-fiber approach pioneered in our group addresses the key challenges of device density and fiber length simultaneously. It allows one to construct structured fibers composed of metals, insulators and semiconductors and enables the incorporation of many devices into a single fiber capable of performing complex tasks such as of angle of incidence and color detection. However, until now, devices built by the preform-to-fiber approach have demonstrated only ohmic behavior due to the chalcogenide semiconductor's amorphous nature and defect density. From a processing standpoint, non-crystallinity is necessary to ensure that the preform viscosity during thermal drawing is large enough to extend the time-scale of breakup driven by surface tension effects in the fluids to times much longer than that of the actual drawing. The structured preform cross-section is maintained into the microscopic fiber only when this requirement is met. Unfortunately, the same disorder that is integral to the fabrication process is detrimental to the semiconductors' electronic properties, imparting large resistivities and effectively pinning the Fermi level near mid-gap. Indeed, the defect density within the mobility gap of many chalcogenides has been found to be 1018-1019 cm-3 eV-1

  17. Product distributions for some thermal energy charge transfer reactions of rare gas ions

    NASA Technical Reports Server (NTRS)

    Anicich, V. G.; Laudenslager, J. B.; Huntress, W. T., Jr.; Futrell, J. H.

    1977-01-01

    Ion cyclotron resonance methods were used to measure the product distributions for thermal-energy charge-transfer reactions of He(+), Ne(+), and Ar(+) ions with N2, O2, CO, NO, CO2, and N2O. Except for the He(+)-N2 reaction, no molecular ions were formed by thermal-energy charge transfer from He(+) and Ne(+) with these target molecules. The propensity for dissociative ionization channels in these highly exothermic charge-transfer reactions at thermal energies contrasts with the propensity for formation of parent molecular ions observed in photoionization experiments and in high-energy charge-transfer processes. This difference is explained in terms of more stringent requirements for energy resonance and favorable Franck-Condon factors at thermal ion velocities.

  18. Advanced thermal energy management: A thermal test bed and heat pipe simulation

    NASA Technical Reports Server (NTRS)

    Barile, Ronald G.

    1986-01-01

    Work initiated on a common-module thermal test simulation was continued, and a second project on heat pipe simulation was begun. The test bed, constructed from surplus Skylab equipment, was modeled and solved for various thermal load and flow conditions. Low thermal load caused the radiator fluid, Coolanol 25, to thicken due to its temperature avoided by using a regenerator-heat-exchanger. Other possible solutions modeled include a radiator heater and shunting heat from the central thermal bus to the radiator. Also, module air temperature can become excessive with high avionics load. A second preoject concerning advanced heat pipe concepts was initiated. A program was written which calculates fluid physical properties, liquid and vapor pressure in the evaporator and condenser, fluid flow rates, and thermal flux. The program is directed to evaluating newer heat pipe wicks and geometries, especially water in an artery surrounded by six vapor channels. Effects of temperature, groove and slot dimensions, and wick properties are reported.

  19. Thermal Transmittance and the Embodied Energy of Timber Frame Lightweight Walls Insulated with Straw and Reed

    NASA Astrophysics Data System (ADS)

    Miljan, M.; Miljan, J.

    2015-11-01

    Sustainable energy use has become topical in the whole world. Energy gives us comfort we are used to. EU and national regulations determine energy efficiency of the buildings. This is one side of the problem - energy efficiency of houses during exploitation. But the other side is primary energy content of used materials and more rational use of resources during the whole life cycle of a building. The latter value constitutes about 8 - 20% from the whole energy content. Calculations of energy efficiency of materials lead us to energy efficiency of insulation materials and to comparison of natural and industrial materials taking into account their thermal conductivity as well as their primary energy content. Case study of the test house (built in 2012) insulated with straw bales gave the result that thermal transmittance of investigated straw bale walls was according to the minimum energy efficiency requirements set in Estonia U = 0.12 - 0.22 W/m2K (for walls).

  20. Modeling void growth and movement with phase change in thermal energy storage canisters

    NASA Technical Reports Server (NTRS)

    Darling, Douglas; Namkoong, David; Skarda, J. Raymond Lee

    1993-01-01

    A scheme was developed to model the thermal hydrodynamic behavior of thermal energy storage salts. The model included buoyancy, surface tension, viscosity, phases change with density difference, and void growth and movement. The energy, momentum, and continuity equations were solved using a finite volume formulation. The momentum equation was divided into two pieces. The void growth and void movement are modeled between the two pieces of the momentum equations. Results showed this scheme was able to predict the behavior of thermal energy storage salts.

  1. Preparation, characterization, and thermal properties of starch microencapsulated fatty acids as phase change materials thermal energy storage applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stable starch-oil composites can be prepared from renewable resources by excess steam jet-cooking aqueous slurries of starch and vegetable oils or other hydrophobic materials. Fatty acids such as stearic acid are promising phase change materials (PCMs) for latent heat thermal energy storage applica...

  2. Equilibrium geochemical modeling of a seasonal thermal energy storage aquifer field test

    NASA Technical Reports Server (NTRS)

    Stottlemyre, J. S.

    1980-01-01

    A geochemical mathematical modeling study designed to investigate the well plugging problems encountered at the Auburn University experimental field tests is summarized. The results, primarily of qualitative interest, include: (1) loss of injectivity was probably due to a combination of native particulate plugging and clay swelling and dispersion; (2) fluid-fluid incompatibilities, hydrothermal reactions, and oxidation reactions were of insignificant magnitude or too slow to have contributed markedly to the plugging; and (3) the potential for and contributions from temperature-induced dissolved gas solubility reductions, capillary boundary layer viscosity increases, and microstructural deformation cannot be deconvolved from the available data.

  3. Seasonal thermal energy storage in aquifers: Mathematical modeling studies in 1979

    NASA Technical Reports Server (NTRS)

    Tsang, C. F.

    1980-01-01

    A numerical model of water and heat flow in geologic media was developed, verified, and tested. The hydraulic parameters (transmittivity and storativity) and the location of a linear hydrologic barrier were simulated and compared with results from field experiments involving two injection-storage-recovery cycles. For both cycles, the initial simulated and observed temperatures agree (55c).

  4. Thermal Performance Benchmarking; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Moreno, Gilbert

    2015-06-09

    This project proposes to seek out the SOA power electronics and motor technologies to thermally benchmark their performance. The benchmarking will focus on the thermal aspects of the system. System metrics including the junction-to-coolant thermal resistance and the parasitic power consumption (i.e., coolant flow rates and pressure drop performance) of the heat exchanger will be measured. The type of heat exchanger (i.e., channel flow, brazed, folded-fin) and any enhancement features (i.e., enhanced surfaces) will be identified and evaluated to understand their effect on performance. Additionally, the thermal resistance/conductivity of the power module’s passive stack and motor’s laminations and copper winding bundles will also be measured. The research conducted will allow insight into the various cooling strategies to understand which heat exchangers are most effective in terms of thermal performance and efficiency. Modeling analysis and fluid-flow visualization may also be carried out to better understand the heat transfer and fluid dynamics of the systems.

  5. Thermal and mechanical energy-storage program: project summary data, FY 1980

    SciTech Connect

    Not Available

    1980-03-01

    The Department of Energy's Division of Energy Storage Systems (STOR) is supporting a broad range of projects to conserve energy and to make possible shifting away from oil and natural gas by developing new and/or improved energy-storage systems applicable to central power generation, dispersed power generation, solar and waste heat utilization, and vehicle propulsion. These programs include: Thermal Energy Storage; Chemical/Hydrogen Energy Storage; Mechanical and Magnetic Energy Storage; and Underground Energy Storage. Technical and Economic Analysis is supported concurrently to evaluate competitive energy storage options. This summary report addresses the above categories except for Technical and Economic Analysis. Thermal and Chemical/Hydrdogen Energy Storage technologies offer the greatest potential for near-term impact of all the storage technologies under development. During FY 80, STOR will commit nearly $32 million to the Thermal and Mechanical Energy Storage Program. The breakdown of budget authorized funding for FY 1979 and Fy 1980 is shown. This publication consists principally of summary sheets for each active project in the Thermal, Chemical/Hydrogen, and Mechanical Energy Storage Program for FY 1979. Each summary includes: project title, principal investigator, organization, project goals, project status, contract number, contract period, funding level and funding source. An overview section is given before each set of project summaries.

  6. Enhanced thermal conductivity of form-stable phase change composite with single-walled carbon nanotubes for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Qian, Tingting; Li, Jinhong; Feng, Wuwei; Nian, Hong’En

    2017-03-01

    A striking contrast in the thermal conductivities of polyethylene glycol (PEG)/diatomite form-stable phase change composite (fs-PCC) with single-walled carbon nanotubes (SWCNs) as nano-additive has been reported in our present study. Compared to the pure PEG, the thermal conductivity of the prepared fs-PCC has increased from 0.24 W/mK to 0.87 W/Mk with a small SWCNs loading of 2 wt%. SWCNs are decorated on the inner surface of diatomite pores whilst retaining its porous structure. Compared to PEG/diatomite fs-PCC, the melting and solidification time of the PEG/diatomite/SWCNs fs-PCC are respectively decreased by 54.7% and 51.1%, and its thermal conductivity is 2.8 times higher. The composite can contain PEG as high as 60 wt% and maintain its original shape perfectly without any PEG leakage after subjected to 200 melt-freeze cycles. DSC results indicates that the melting point of the PEG/diatomite/SWCNs fs-PCC shifts to a lower temperature while the solidification point shifts to a higher temperature due to the presence of SWCNs. Importantly, the use of SWCNs is found to have clear beneficial effects for enhancing the thermal conductivity and thermal storage/release rates, without affecting thermal properties, chemical compatibility and thermal stability. The prepared PEG/diatomite/SWCNs fs-PCC exhibits excellent chemical and thermal durability and has potential application in solar thermal energy storage and solar heating.

  7. Enhanced thermal conductivity of form-stable phase change composite with single-walled carbon nanotubes for thermal energy storage.

    PubMed

    Qian, Tingting; Li, Jinhong; Feng, Wuwei; Nian, Hong'en

    2017-03-16

    A striking contrast in the thermal conductivities of polyethylene glycol (PEG)/diatomite form-stable phase change composite (fs-PCC) with single-walled carbon nanotubes (SWCNs) as nano-additive has been reported in our present study. Compared to the pure PEG, the thermal conductivity of the prepared fs-PCC has increased from 0.24 W/mK to 0.87 W/Mk with a small SWCNs loading of 2 wt%. SWCNs are decorated on the inner surface of diatomite pores whilst retaining its porous structure. Compared to PEG/diatomite fs-PCC, the melting and solidification time of the PEG/diatomite/SWCNs fs-PCC are respectively decreased by 54.7% and 51.1%, and its thermal conductivity is 2.8 times higher. The composite can contain PEG as high as 60 wt% and maintain its original shape perfectly without any PEG leakage after subjected to 200 melt-freeze cycles. DSC results indicates that the melting point of the PEG/diatomite/SWCNs fs-PCC shifts to a lower temperature while the solidification point shifts to a higher temperature due to the presence of SWCNs. Importantly, the use of SWCNs is found to have clear beneficial effects for enhancing the thermal conductivity and thermal storage/release rates, without affecting thermal properties, chemical compatibility and thermal stability. The prepared PEG/diatomite/SWCNs fs-PCC exhibits excellent chemical and thermal durability and has potential application in solar thermal energy storage and solar heating.

  8. Enhanced thermal conductivity of form-stable phase change composite with single-walled carbon nanotubes for thermal energy storage

    PubMed Central

    Qian, Tingting; Li, Jinhong; Feng, Wuwei; Nian, Hong’en

    2017-01-01

    A striking contrast in the thermal conductivities of polyethylene glycol (PEG)/diatomite form-stable phase change composite (fs-PCC) with single-walled carbon nanotubes (SWCNs) as nano-additive has been reported in our present study. Compared to the pure PEG, the thermal conductivity of the prepared fs-PCC has increased from 0.24 W/mK to 0.87 W/Mk with a small SWCNs loading of 2 wt%. SWCNs are decorated on the inner surface of diatomite pores whilst retaining its porous structure. Compared to PEG/diatomite fs-PCC, the melting and solidification time of the PEG/diatomite/SWCNs fs-PCC are respectively decreased by 54.7% and 51.1%, and its thermal conductivity is 2.8 times higher. The composite can contain PEG as high as 60 wt% and maintain its original shape perfectly without any PEG leakage after subjected to 200 melt-freeze cycles. DSC results indicates that the melting point of the PEG/diatomite/SWCNs fs-PCC shifts to a lower temperature while the solidification point shifts to a higher temperature due to the presence of SWCNs. Importantly, the use of SWCNs is found to have clear beneficial effects for enhancing the thermal conductivity and thermal storage/release rates, without affecting thermal properties, chemical compatibility and thermal stability. The prepared PEG/diatomite/SWCNs fs-PCC exhibits excellent chemical and thermal durability and has potential application in solar thermal energy storage and solar heating. PMID:28300191

  9. The influence of thermal energy exchange on the activity and energetics of yellow-bellied marmots

    SciTech Connect

    Melcher, J.C.

    1987-01-01

    The energetics of yellow-bellied marmots (Marmota flaviventris), large hibernating ground squirrels were investigated. Marmots typically inhabit montane regions with short growing seasons. Minimization of energy expenditure by hibernation is essential for overwinter survival, whereas maximization of energy intake is important during the active season. Marmots near the Rocky Mountain Biological Laboratory in southwestern Colorado are active for only 4 to 5 months each year. During this time they must reproduce, grow, and store enough fat to survive hibernation. 64 refs., 13 figs., 10 tabs.

  10. 40 CFR 74.47 - Transfer of allowances from the replacement of thermal energy-combustion sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... replacement of thermal energy-combustion sources. 74.47 Section 74.47 Protection of Environment ENVIRONMENTAL...—combustion sources. (a) Thermal energy plan—(1) General provisions. The designated representative of an opt... quarter the replacement unit(s) will replace thermal energy of the opt-in source; (ii) The...

  11. 40 CFR 74.47 - Transfer of allowances from the replacement of thermal energy-combustion sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... replacement of thermal energy-combustion sources. 74.47 Section 74.47 Protection of Environment ENVIRONMENTAL...—combustion sources. (a) Thermal energy plan—(1) General provisions. The designated representative of an opt... quarter the replacement unit(s) will replace thermal energy of the opt-in source; (ii) The...

  12. 40 CFR 74.47 - Transfer of allowances from the replacement of thermal energy-combustion sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... replacement of thermal energy-combustion sources. 74.47 Section 74.47 Protection of Environment ENVIRONMENTAL...—combustion sources. (a) Thermal energy plan—(1) General provisions. The designated representative of an opt... quarter the replacement unit(s) will replace thermal energy of the opt-in source; (ii) The...

  13. 40 CFR 74.47 - Transfer of allowances from the replacement of thermal energy-combustion sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and End of Year Compliance § 74.47 Transfer of allowances from the replacement of thermal energy... seeking to transfer allowances based on the replacement of thermal energy. (3) Contents. Each thermal... energy plan, the Administrator will annually transfer allowances to the compliance account of each...

  14. Energy distributions exhibited during thermal runaway of commercial lithium ion batteries used for human spaceflight applications

    NASA Astrophysics Data System (ADS)

    Yayathi, Sandeep; Walker, William; Doughty, Daniel; Ardebili, Haleh

    2016-10-01

    Lithium ion (Li-ion) batteries provide low mass and energy dense solutions necessary for space exploration, but thermal related safety concerns impede the utilization of Li-ion technology for human applications. Experimental characterization of thermal runaway energy release with accelerated rate calorimetry supports safer thermal management systems. 'Standard' accelerated rate calorimetry setup provides means to measure the addition of energy exhibited through the body of a Li-ion cell. This study considers the total energy generated during thermal runaway as distributions between cell body and hot gases via inclusion of a unique secondary enclosure inside the calorimeter; this closed system not only contains the cell body and gaseous species, but also captures energy release associated with rapid heat transfer to the system unobserved by measurements taken on the cell body. Experiments include Boston Power Swing 5300, Samsung 18650-26F and MoliCel 18650-J Li-ion cells at varied states-of-charge. An inverse relationship between state-of-charge and onset temperature is observed. Energy contained in the cell body and gaseous species are successfully characterized; gaseous energy is minimal. Significant additional energy is measured with the heating of the secondary enclosure. Improved calorimeter apparatus including a secondary enclosure provides essential capability to measuring total energy release distributions during thermal runaway.

  15. Transition Region Emission and the Energy Input to Thermal Plasma in Solar Flares

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.; Holman, Gordon D.; Dennis, Brian R.; Haga, Leah; Raymond, John C.; Panasyuk, Alexander

    2005-01-01

    Understanding the energetics of solar flares depends on obtaining reliable determinations of the energy input to flare plasma. X-ray observations of the thermal bremsstrahlung from hot flare plasma provide temperatures and emission measures which, along with estimates of the plasma volume, allow the energy content of this hot plasma to be computed. However, if thermal energy losses are significant or if significant energy goes directly into cooler plasma, this is only a lower limit on the total energy injected into thermal plasma during the flare. We use SOHO UVCS observations of O VI flare emission scattered by coronal O VI ions to deduce the flare emission at transition region temperatures between 100,000 K and 1 MK for the 2002 July 23 and other flares. We find that the radiated energy at these temperatures significantly increases the deduced energy input to the thermal plasma, but by an amount that is less than the uncertainty in the computed energies. Comparisons of computed thermal and nonthermal electron energies deduced from RHESSI, GOES, and UVCS are shown.

  16. Performance analysis of different ORC configurations for thermal energy and LNG cold energy hybrid power generation system

    NASA Astrophysics Data System (ADS)

    Sun, Zhixin; Wang, Feng; Wang, Shujia; Xu, Fuquan; Lin, Kui

    2017-01-01

    This paper presents a thermal energy and Liquefied natural gas (LNG) cold energy hybrid power generation system. Performances of four different Organic Rankine cycle (ORC) configurations (the basic, the regenerative, the reheat and the regenerative-reheat ORCs) are studied based on the first and the second law of thermodynamics. Dry organic fluid R245fa is selected as the typical working fluid. Parameter analysis is also conducted in this paper. The results show that regeneration could not increase the thermal efficiency of the thermal and cold energy hybrid power generation system. ORC with the reheat process could produce more specific net power output but it may also reduce the system thermal efficiency. The basic and the regenerative ORCs produce higher thermal efficiency while the regenerative-reheat ORC performs best in the exergy efficiency. A preheater is necessary for the thermal and cold energy hybrid power generation system. And due to the presence of the preheater, there will be a step change of the system performance as the turbine inlet pressure rises.

  17. Solar energy system performance evaluation: A seasonal report for SEMCO, Macon, Georgia

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The solar energy system for heating water in a single-family residence for a family of four is described. The system operation, the operating energy, energy savings, maintenance, and performance are analyzed.

  18. Importance of recent shifts in soil thermal dynamics on growing season length, productivity, and carbon sequestration in terrestrial high-latitude ecosystems

    USGS Publications Warehouse

    Euskirchen, E.S.; McGuire, A.D.; Kicklighter, D.W.; Zhuang, Q.; Clein, J.S.; Dargaville, R.J.; Dye, D.G.; Kimball, J.S.; McDonald, K.C.; Melillo, J.M.; Romanovsky, V.E.; Smith, N.V.

    2006-01-01

    In terrestrial high-latitude regions, observations indicate recent changes in snow cover, permafrost, and soil freeze-thaw transitions due to climate change. These modifications may result in temporal shifts in the growing season and the associated rates of terrestrial productivity. Changes in productivity will influence the ability of these ecosystems to sequester atmospheric CO2. We use the terrestrial ecosystem model (TEM), which simulates the soil thermal regime, in addition to terrestrial carbon (C), nitrogen and water dynamics, to explore these issues over the years 1960-2100 in extratropical regions (30-90??N). Our model simulations show decreases in snow cover and permafrost stability from 1960 to 2100. Decreases in snow cover agree well with National Oceanic and Atmospheric Administration satellite observations collected between the years 1972 and 2000, with Pearson rank correlation coefficients between 0.58 and 0.65. Model analyses also indicate a trend towards an earlier thaw date of frozen soils and the onset of the growing season in the spring by approximately 2-4 days from 1988 to 2000. Between 1988 and 2000, satellite records yield a slightly stronger trend in thaw and the onset of the growing season, averaging between 5 and 8 days earlier. In both, the TEM simulations and satellite records, trends in day of freeze in the autumn are weaker, such that overall increases in growing season length are due primarily to earlier thaw. Although regions with the longest snow cover duration displayed the greatest increase in growing season length, these regions maintained smaller increases in productivity and heterotrophic respiration than those regions with shorter duration of snow cover and less of an increase in growing season length. Concurrent with increases in growing season length, we found a reduction in soil C and increases in vegetation C, with greatest losses of soil C occurring in those areas with more vegetation, but simulations also suggest that

  19. Focusing on the future: Solar thermal energy systems emerge as competitive technologies with major economic potential

    NASA Astrophysics Data System (ADS)

    1989-03-01

    Hundreds of thousands of U.S. citizens are now receiving a portion of their daily demand for electricity from large-scale solar thermal electric generating stations-power plants that use concentrated solar energy to drive electric power generators. Just as with coal, fuel oil, natural gas, and nuclear energy, concentrated solar energy can create working temperatures of around 600C and much higher. Also, solar power plants contribute almost nothing to the atmospheric greenhouse effect and pose few, if any, of the other environmental problems associated with conventional energy sources. As a result of research and development within the national Solar Thermal Technology Program of the U.S. Department of Energy (DOE), solar thermal energy is on the threshold of competing economically with conventional power plants and is now viable for international markets. Its potential for spurring American economic growth and exports is significant.

  20. Collection and dissemination of thermal energy storage system information for the pulp and paper industry

    NASA Technical Reports Server (NTRS)

    Edde, H.

    1981-01-01

    The collection and dissemination of thermal energy storage (TES) system technology for the pulp and paper industry with the intent of reducing fossil fuel usage is discussed. The study plan is described and a description presented of example TES systems.