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1

Thermal Performance of Vegetative Roofing Systems  

SciTech Connect

Vegetative roofing, otherwise known as green or garden roofing, has seen tremendous growth in the last decade in the United States. The numerous benefits that green roofs provide have helped to fuel their resurgence in industrial and urban settings. There are many environmental and economical benefits that can be realized by incorporating a vegetative roof into the design of a building. These include storm-water retention, energy conservation, reduction in the urban heat island effect, increased longevity of the roofing membrane, the ability of plants to create biodiversity and filter air contaminants, and beautification of the surroundings by incorporating green space. The vegetative roof research project at Oak Ridge National Laboratory (ORNL) was initiated to quantify the thermal performance of various vegetative roofing systems relative to black and white roofs. Single Ply Roofing Institute (SPRI) continued its long-term commitment to cooperative research with ORNL in this project. Low-slope roof systems for this study were constructed and instrumented for continuous monitoring in the mixed climate of East Tennessee. This report summarizes the results of the annual cooling and heating loads per unit area of three vegetative roofing systems with side-by-side comparison to black and white roofing systems as well as a test section with just the growing media without plants. Results showed vegetative roofs reduced heat gain (reduced cooling loads) compared to the white control system due to the thermal mass, extra insulation, and evapo-transpiration associated with the vegetative roofing systems. The 4-inch and tray systems reduced the heat gain by approximately 61%, while the reduction with the 8-inch vegetative roof was found to be approximately 67%. The vegetative roofing systems were more effective in reducing heat gain than in reducing heat losses (heating loads). The reduction in heat losses for the 4-inch and tray systems were found to be approximately 40% in the mixed climate of East Tennessee. It should be noted that these values are climate dependent. Vegetative roofs also reduced the temperature (heat exposure) and temperature fluctuations (thermal stress) experienced by the membrane. In the cooling season of East Tennessee, the average peak temperature of the 4-inch and tray systems was found to be approximately 94 F cooler than the control black roofing system. The average temperature fluctuations at the membrane for the 4-inch and tray systems were found to be approximately 10 F compared to 125 F for black and 64 F for white systems. As expected, the 8-inch vegetative roof had the lowest fluctuations at approximately 2 F. Future work will include modeling of the energy performance of vegetative roof panels in the test climate of East Tennessee. The validated model then will be used to predict energy use in roofs with different insulation levels and in climates different from the test climate.

Desjarlais, Andre Omer [ORNL; Zaltash, Abdolreza [ORNL; Atchley, Jerald Allen [ORNL; Ennis, Mike J [ORNL

2010-01-01

2

Effect of Surface Mass on Roof Thermal Performance  

E-print Network

EFFECT OF SURFACE MASS ON ROOF THERMAL PERFORMANCE KENNETH E. WILKES, PAUL H. SHIPP, AND JOHN P. SANDERS Staff Members Oak Ridge National Laboratory Oak Ridge, Tennessee ABSTRACT The roof of a building is exposed to the most severe...

Wilkes, K. E.; Shipp, P. H.; Sanders, J. P.

1988-01-01

3

Analysis of roof systems thermal performance from field data  

Microsoft Academic Search

According to the most recent Project Pinpoint, the percentage of new and replacement low-slope roofs in the United States now being insulated exceeds 88 percent. This is dramatic evidence that good thermal performance is a worthy investment and has become an accepted design characteristic of roof systems despite higher initial costs. As the interest in thermal performance increases so do

G. E. Courville; P. W. Childs; R. L. Linkous

1991-01-01

4

Comparative Summer Thermal Performance of Finished and Unfinished Metal Roofing Products with Composition Shingles  

E-print Network

the underside of the roof decking. The test results were used to determine relative thermal performance of various roofing systems under typical Florida summer conditions. Measured impacts included changes to ceiling heat flux and attic air temperature which...

Parker, D. S.; Sherwin, J.; Sonne, J.

2004-01-01

5

Thermal performance analysis and economic evaluation of roof-integrated solar concrete collector  

Microsoft Academic Search

This paper examines the thermal performance of a roof-integrated solar concrete collector for reducing heat gain to a house and providing domestic hot water. The solar concrete collector is made of PVC pipes embedded in deck slab or concrete roof. No glazing on the top of the solar concrete collector or insulation at the back has been used as in

Rangsit Sarachitti; Chaicharn Chotetanorm; Charoenporn Lertsatitthanakorn; Montana Rungsiyopas

2011-01-01

6

A parametric study of the thermal performance of green roofs in different climates through energy modeling  

NASA Astrophysics Data System (ADS)

In recent years, there has been great interest in the potential of green roofs as an alternative roofing option to reduce the energy consumed by individual buildings as well as mitigate large scale urban environmental problems such as the heat island effect. There is a widespread recognition and a growing literature of measured data that suggest green roofs can reduce building energy consumption. This thesis investigates the potential of green roofs in reducing the building energy loads and focuses on how the different parameters of a green roof assembly affect the thermal performance of a building. A green roof assembly is modeled in Design Builder- a 3D graphical design modeling and energy use simulation program (interface) that uses the EnergyPlus simulation engine, and the simulated data set thus obtained is compared to field experiment data to validate the roof assembly model on the basis of how accurately it simulates the behavior of a green roof. Then the software is used to evaluate the thermal performance of several green roof assemblies under three different climate types, looking at the whole building energy consumption. For the purpose of this parametric simulation study, a prototypical single story small office building is considered and one parameter of the green roof is altered for each simulation run in order to understand its effect on building's energy loads. These parameters include different insulation thicknesses, leaf area indices (LAI) and growing medium or soil depth, each of which are tested under the three different climate types. The energy use intensities (EUIs), the peak and annual heating and cooling loads resulting from the use of these green roof assemblies are compared with each other and to a cool roof base case to determine the energy load reductions, if any. The heat flux through the roof is also evaluated and compared. The simulation results are then organized and finally presented as a decision support tool that would facilitate the adoption and appropriate utilization of green roof technologies and make it possible to account for green roof benefits in energy codes and related energy efficiency standards and rating systems such as LEED.

Mukherjee, Sananda

7

CFD modelling and thermal performance analysis of a wooden ventilated roof structure  

Microsoft Academic Search

Thermal comfort and energy saving are objectives of key significance that building design must meet. Since a low energy building\\u000a can be obtained as a result of the good realization of all its components, roofs call for particular attention as they represent\\u000a a large part of a building’s total surface area. In this paper the benefit of using ventilated roofs

Giacomo Villi; Wilmer Pasut; Michele De Carli

2009-01-01

8

Thermal performance and embodied energy analysis of a passive house – Case study of vault roof mud-house in India  

Microsoft Academic Search

This paper investigates thermal performance of an existing eco-friendly and low embodied energy vault roof passive house (or mud-house) located at Solar Energy Park of IIT Delhi, New Delhi (India). Based on embodied energy analysis, the energy payback time for the mud-house was determined as 18 years. The embodied energy per unit floor area of R.C.C. building (3702.3MJ\\/m2) is quiet

Arvind Chel; G. N. Tiwari

2009-01-01

9

Green roofs are not created equal: the hydrologic and thermal performance of six different extensive green roofs and reflective and non-reflective roofs in a sub-tropical climate  

Microsoft Academic Search

Green roofs have the potential to retain stormwater on the roof surface and lower the thermal loading on buildings. Because\\u000a of this, the greatest environmental benefits from green roofs might be achieved in subtropical climates characterized by high\\u000a temperatures and intense rain events. There is, however, little research to support this. In a replicated study in Texas,\\u000a we compared the

Mark T. Simmons; Brian Gardiner; Steve Windhager; Jeannine Tinsley

2008-01-01

10

Thermal Performance of Exposed Composed Roofs in Very Hot Dry Desert Region in Egypt (Toshky)  

E-print Network

that the thermal transmittance (UValue) has a major role in chosen the constructed materials. Also the thermal insulation considered the suitable manner for damping the thermal stresses through day time and makes the interior environment of the building near...

Khalil, M. H.; Sheble, S.; Morsey, M. S.; Fakhry, S.

2010-01-01

11

Thermal Performance of Green Roofs: A Case Study in a Tropical Region  

Microsoft Academic Search

Caretakers and others employees of apartment building usually have to stay during long periods of time in shelters that do not offer minimum conditions of thermal comfort. The terrible urban violence induces many designers to conceive these spaces as kinds of warlike shelters, almost without ventilation and with an excess of glass windows that, without appropriate protection, still heat even

Caroline Santana de Morais; Maurício Roriz

2003-01-01

12

The Impact of Above-Sheathing Ventilation on the Thermal and Moisture Performance of Steep-Slope Residential Roofs and Attics  

E-print Network

THE IMPACT OF ABOVE-SHEATHING VENTILATION ON THE THERMAL AND MOISTURE PERFORMANCE OF STEEP-SLOPE RESIDENTIAL ROOFS AND ATTICS William (Bill) Miller Research Scientist Oak Ridge National Laboratory Oak Ridge, Tennessee Joe Wilson Product... with and without infrared blocking color pigments (IrBCPs) and with and without above-sheathing ventilation. The combination of increased solar reflectance and above-sheathing ventilation reduced the heat flow penetrating the attic floor by 70% as compared...

Miller, W.; Karagiozis, A.; Wilson, J.

2006-01-01

13

Roof-Integrated Solar Thermal System (Dawn Solar Systems)  

Microsoft Academic Search

The Dawn Solar Systems team worked on improving the efficiency of a roof-integrated solar thermal system used for residential hot water heating. Through the use of a comprehensive system model and a simulated roof test stand, the team predicted the type of design improvements that would increase efficiency while keeping the cost to within 15% of the baseline. A strategic

Jonathan Chambers; Que Anh Nguyen; Bret Richmond; Sara Schwalbenberg; Polina Segalova; Greg Neufeld; Holly Mead

2006-01-01

14

Performance and costs of a roof-sized PV\\/thermal array combined with a ground coupled heat pump  

Microsoft Academic Search

A photovoltaic\\/thermal (PVT) panel is a combination of photovoltaic cells with a solar thermal collector, generating solar electricity and solar heat simultaneously. Hence, PVT panels are an alternative for a combination of separate PV panels and solar thermal collectors. A promising system concept, consisting of 25m2 of PVT panels and a ground coupled heat pump, has been simulated in TRNSYS.

M. Bakker; H. A. Zondag; M. J. Elswijk; K. J. Strootman; M. J. M. Jong

2005-01-01

15

Energy Performance Aspects of a Florida Green Roof  

E-print Network

ENERGY PERFORMANCE ASPECTS OF A FLORIDA GREEN ROOF Jeffrey K. Sonne Senior Research Engineer Florida Solar Energy Center Cocoa, FL ABSTRACT Previous green roof studies have found that planted roofs significantly reduce roof temperatures... Proceedings, Atlanta, GA, May 2005. 5. Wong, et al., “The Effects of Rooftop Garden on Energy Consumption of a Commercial Building in Singapore”, Energy and Buildings, Volume 35, 2003, p. 353-364. 6. Christian, Jeffrey E. and Thomas W. Petrie...

Sonne, J.

2006-01-01

16

Performance of trombe walls and roof pond systems  

Microsoft Academic Search

This paper describes an analysis of the periodic heat transfer through thermal storage walls and roof pond systems subjected to periodic solar radiation and atmospheric air on one side and in contact with room air at constant temperature (corresponding to air-conditioned rooms) on the other. A one-dimensional heat conduction equation for temperature distribution in the walls and roof has been

M. S. Sodha; S. C. Kaushik; J. K. Nayak

1981-01-01

17

Roof heat loss detection using airborne thermal infrared imagery  

NASA Astrophysics Data System (ADS)

As part of the Austrian and European attempt to reduce energy consumption and greenhouse gas emissions, thermal rehabilitation and the improvement of the energy efficiency of buildings became an important topic in research as well as in building construction and refurbishment. Today, in-situ thermal infrared measurements are routinely used to determine energy loss through the building envelope. However, in-situ thermal surveys are expensive and time consuming, and in many cases the detection of the amount and location of waste heat leaving building through roofs is not possible with ground-based observations. For some years now, a new generation of high-resolution thermal infrared sensors makes it possible to survey heat-loss through roofs at a high level of detail and accuracy. However, to date, comparable studies have mainly been conducted on buildings with uniform roof covering and provided two-dimensional, qualitative information. This pilot study aims to survey the heat-loss through roofs of the buildings of the University of Graz (Austria) campus by using high-resolution airborne thermal infrared imagery (TABI 1800 - Thermal Airborne Broadband imager). TABI-1800 acquires data in a spectral range from 3.7 - 4.8 micron, a thermal resolution of 0.05 °C and a spatial resolution of 0.6 m. The remote sensing data is calibrated to different roof coverings (e.g. clay shingle, asphalt shingle, tin roof, glass) and combined with a roof surface model to determine the amount of waste heat leaving the building and to identify hot spots. The additional integration of information about the conditions underneath the roofs into the study allows a more detailed analysis of the upward heat flux and is a significant improvement of existing methods. The resulting data set provides useful information to the university facility service for infrastructure maintenance, especially in terms of attic and roof insulation improvements. Beyond that, the project is supposed to raise public awareness in the context of climate-neutral actions, and in a long run, contribute to significantly reduce energy consumption and GHG emissions.

Kern, K.; Bauer, C.; Sulzer, W.

2012-12-01

18

Hygrothermal Performance of West Coast Wood Deck Roofing System  

SciTech Connect

Simulations of roofing assemblies are necessary in order to understand and adequately predict actual the hygrothermal performance. At the request of GAF, simulations have been setup to verify the difference in performance between white and black roofing membrane colors in relation to critical moisture accumulation for traditional low slope wood deck roofing systems typically deployed in various western U.S. Climate Zones. The performance of these roof assemblies has been simulated in the hygrothermal calculation tool of WUFI, from which the result was evaluated based on a defined criterion for moisture safety. The criterion was defined as the maximum accepted water content for wood materials and the highest acceptable moisture accumulation rate in relation to the risk of rot. Based on the criterion, the roof assemblies were certified as being either safe, risky or assumed to fail. The roof assemblies were simulated in different western climates, with varying insulation thicknesses, two different types of wooden decking, applied with varying interior moisture load and with either a high or low solar absorptivity at the roof surface (black or white surface color). The results show that the performance of the studied roof assemblies differs with regard to all of the varying parameters, especially the climate and the indoor moisture load.

Pallin, Simon B [ORNL; Kehrer, Manfred [ORNL; Desjarlais, Andre Omer [ORNL

2014-02-01

19

Modelling of green roofs' hydrologic performance using EPA's SWMM.  

PubMed

Green roofs significantly affect the increase in water retention and thus the management of rain water in urban areas. In Poland, as in many other European countries, excess rainwater resulting from snowmelt and heavy rainfall contributes to the development of local flooding in urban areas. Opportunities to reduce surface runoff and reduce flood risks are among the reasons why green roofs are more likely to be used also in this country. However, there are relatively few data on their in situ performance. In this study the storm water performance was simulated for the green roofs experimental plots using the Storm Water Management Model (SWMM) with Low Impact Development (LID) Controls module (version 5.0.022). The model consists of many parameters for a particular layer of green roofs but simulation results were unsatisfactory considering the hydrologic response of the green roofs. For the majority of the tested rain events, the Nash coefficient had negative values. It indicates a weak fit between observed and measured flow-rates. Therefore complexity of the LID module does not affect the increase of its accuracy. Further research at a technical scale is needed to determine the role of the green roof slope, vegetation cover and drying process during the inter-event periods. PMID:23823537

Burszta-Adamiak, E; Mrowiec, M

2013-01-01

20

Modelling of green roof hydrological performance for urban drainage applications  

NASA Astrophysics Data System (ADS)

Green roofs are being widely implemented for stormwater management and their impact on the urban hydrological cycle can be evaluated by incorporating them into urban drainage models. This paper presents a model of green roof long term and single event hydrological performance. The model includes surface and subsurface storage components representing the overall retention capacity of the green roof which is continuously re-established by evapotranspiration. The runoff from the model is described through a non-linear reservoir approach. The model was calibrated and validated using measurement data from 3 different extensive sedum roofs in Denmark. These data consist of high-resolution measurements of runoff, precipitation and atmospheric variables in the period 2010-2012. The hydrological response of green roofs was quantified based on statistical analysis of the results of a 22-year (1989-2010) continuous simulation with Danish climate data. The results show that during single events, the 10 min runoff intensities were reduced by 10-36% for 5-10 years return period and 40-78% for 0.1-1 year return period; the runoff volumes were reduced by 2-5% for 5-10 years return period and 18-28% for 0.1-1 year return period. Annual runoff volumes were estimated to be 43-68% of the total precipitation. The peak time delay was found to greatly vary from 0 to more than 40 min depending on the type of event, and a general decrease in the time delay was observed for increasing rainfall intensities. Furthermore, the model was used to evaluate the variation of the average annual runoff from green roofs as a function of the total available storage and vegetation type. The results show that even a few millimeters of storage can reduce the mean annual runoff by up to 20% when compared to a traditional roof and that the mean annual runoff is not linearly related to the storage. Green roofs have therefore the potential to be important parts of future urban stormwater management plans.

Locatelli, Luca; Mark, Ole; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten; Bergen Jensen, Marina; Binning, Philip John

2014-11-01

21

The GREENROOF module (v7.3) for modelling green roof hydrological and energetic performances within TEB  

NASA Astrophysics Data System (ADS)

The need to prepare cities for climate change adaptation requests the urban modeller community to implement sustainable adaptation strategies within their models to be tested against specific city morphologies and scenarios. Greening city roofs is part of these strategies. In this context, the GREENROOF module for TEB (town energy balance) has been developed to model the interactions between buildings and green roof systems at the scale of the city. This module, which combines the ISBA model (Interaction between Soil Biosphere and Atmosphere) and TEB, allows for one to describe an extensive green roof composed of four functional layers (vegetation - grasses or sedums; substrate; retention/drainage layers; and artificial roof layers) and to model vegetation-atmosphere fluxes of heat, water and momentum, as well as the hydrological fluxes throughout the substrate and the drainage layers, and the thermal fluxes throughout the natural and artificial layers of the green roof. TEB-GREENROOF (SURFEX v7.3) should therefore be able to represent the impact of climate forcings on the functioning of green roof vegetation and, conversely, the influence of the green roof on the local climate. An evaluation of GREENROOF is performed for a case study located in Nancy (France) which consists of an instrumented extensive green roof with sedums and substrate and drainage layers that are typical of this kind of construction. After calibration of the drainage layer hydrological characteristics, model results show good dynamics for the substrate water content and the drainage at the green roof base, with nevertheless a tendency to underestimate the water content and overestimate the drainage. This does not impact too much the green roof temperatures, which present a good agreement with observations. Nonetheless GREENROOF tends to overestimate the soil temperatures and their amplitudes, but this effect is less important in the drainage layer. These results are encouraging with regard to modelling the impact of green roofs on thermal indoor comfort and energy consumption at the scale of cities, for which GREENROOF will be running with the building energy version of TEB - TEB-BEM. Moreover, with the green roof studied for GREENROOF evaluation being a type of extensive green roof widespread in cities, the type of hydrological characteristics highlighted for the case study will be used as the standard configuration to model extensive green roof impacts at the scale of cities.

de Munck, C. S.; Lemonsu, A.; Bouzouidja, R.; Masson, V.; Claverie, R.

2013-11-01

22

The GREENROOF module (v7.3) for modelling green roof hydrological and energetic performances within TEB  

NASA Astrophysics Data System (ADS)

The need to prepare cities for climate change adaptation requests the urban modeller community to implement within their models sustainable adaptation strategies to be tested against specific city morphologies and scenarios. Greening city roofs is part of these strategies. In this context, a GREENROOF module for TEB (Town Energy Balance) has been developed to model the interactions between buildings and green roof systems at the scale of the city. This module allows one to describe an extensive green roof composed of four functional layers (vegetation - grasses or sedums, substrate, retention/drainage layers and artificial roof layers) and to model vegetation-atmosphere fluxes of heat, water and momentum, as well as the hydrological and thermal fluxes throughout the substrate and the drainage layers, and the thermal coupling with the structural building envelope. TEB-GREENROOF (v7.3) is therefore able to represent the impact of climate forcings on the functioning of the green roof vegetation and, conversely, the influence of the green roof on the local climate. A calibration exercise to adjust the model to the peculiar hydrological characteristics of the substrates and drainage layers commonly found on green roofs is performed for a case study located in Nancy (France) which consists of an extensive green roof with sedums. Model results for the optimum hydrological calibration show a good dynamics for the substrate water content which is nevertheless under-estimated but without impacting too much the green roof temperatures since they present a good agreement with observations. These results are encouraging with regard to modelling the impact of green roofs on thermal indoor comfort and energy consumption at the scale of cities, for which GREENROOF will be running with the building energy version of TEB, TEB-BEM. Moreover, the green roof studied for GREENROOF evaluation being a city-widespread type of extensive green roof, the hydrological characteristics derived through the evaluation exercise will be used as the standard configuration to model extensive green roofs at the scale of cities.

de Munck, C. S.; Lemonsu, A.; Bouzouidja, R.; Masson, V.; Claverie, R.

2013-02-01

23

Sedum cools soil and can improve neighboring plant performance during water deficit on a green roof  

Microsoft Academic Search

Green roofs have the potential to function as islands of biodiversity within urban and suburban environments. However, plant diversity is constrained by the harsh environment of a green roof, especially summertime water deficit and heat stress. We hypothesized that Sedum species, which are highly tolerant of the roof-top environment, would reduce peak soil temperature and increase performance of neighboring plants

Colleen Butler; Colin M. Orians

2011-01-01

24

Energy Performance Impacts from Competing Low-slope Roofing Choices and Photovoltaic Technologies  

NASA Astrophysics Data System (ADS)

With such a vast quantity of space, commercial low-slope roofs offer significant potential for sustainable roofing technology deployment. Specifically, building energy performance can be improved by installing rooftop energy technologies such as photovoltaic (PV) panels, and/or including designs such as white or green roofs instead of traditional black. This research aims to inform and support roof decisions through quantified energy performance impacts across roof choices and photovoltaic technologies. The primary dataset for this research was measured over a 16 month period (May 24, 2011 to October 13, 2012) from a large field experiment in Pittsburgh, Pennsylvania on top of a commercial warehouse with white, black and green roof sections, each with portions covered by polycrystalline photovoltaic panels. Results from the Pittsburgh experiment were extended to three different cities (San Diego, CA; Huntsville, AL; and Phoenix, AZ) chosen to represent a wide range of irradiance and temperature values. First, this research evaluated the difference in electricity production from a green-moss roof and black roof underneath photovoltaic panels to determine if the green roof's cooler air increases the panel efficiency. Second, separate studies examine 1) average hourly heat flux by month for unobstructed and shaded roof membranes 2) heat flux peak time delay, and 3) air temperature across roof types. Results of this research show green roofs slightly increased (0.8-1.5%) PV panel efficiency in temperatures approximately at or above 25° C (77°F) compared to black roofs. However in cool climates, like Pittsburgh, the roof type under the PV panels had little overall impact on PV performance when considering year round temperatures. Instead, roof decisions should place a stronger emphasis on heat flux impacts. The green roof outperformed both black and white roofs at minimizing total conductive heat flux. These heat flow values were used to develop a new, straight-forward methodology to roughly estimate heat flux impacts of different roof types in other climates using ambient temperature and solar irradiance. While managing heat flow is important for building energy performance, roof choices need to include a systems level analysis encompassing a year for the specific region to best quantify the overall energy impacts.

Nagengast, Amy L.

25

Establishment and performance of an experimental green roof under extreme climatic conditions.  

PubMed

Green roofs alter the surface energy balance and can help in mitigating urban heat islands. However, the cooling of green roofs due to evapotranspiration strongly depends on the climatic conditions, and vegetation type and density. In the Southern Central Plains of the United States, extreme weather events, such as high winds, heat waves and drought conditions pose challenges for successful implementation of green roofs, and likely alter their standard performance. The National Weather Center Experimental Green Roof, an interdisciplinary research site established in 2010 in Norman, OK, aimed to investigate the ecological performance and surface energy balance of green roof systems. Starting in May 2010, 26months of vegetation studies were conducted and the radiation balance, air temperature, relative humidity, and buoyancy fluxes were monitored at two meteorological stations during April-October 2011. The establishment of a vegetative community trended towards prairie plant dominance. High mortality of succulents and low germination of grasses and herbaceous plants contributed to low vegetative coverage. In this condition succulent diversity declined. Bouteloua gracilis and Delosperma cooperi showed typological dominance in harsh climatic conditions, while Sedum species experienced high mortality. The plant community diversified through volunteers such as Euphorbia maculate and Portulaca maculate. Net radiation measured at a green-roof meteorological station was higher than at a control station over the original, light-colored roofing material. These findings indicate that the albedo of the green roof was lower than the albedo of the original roofing material. The low vegetative coverage during the heat and drought conditions in 2011, which resulted in the dark substrate used in the green roof containers being exposed, likely contributed to the low albedo values. Nevertheless, air temperatures and buoyancy fluxes were often lower over the green roof indicating that higher evapotranspiration rates compensated for the higher net radiation at the green roof. PMID:25613772

Klein, Petra M; Coffman, Reid

2015-04-15

26

Minimal watering regime impacts on desert adapted green roof plant performance  

NASA Astrophysics Data System (ADS)

Roof tops can cover one-fifth of urban areas and can greatly alter the movement of matter and energy in cities. With traditional roofing methods and materials, roof tops readily absorb heat and as a result, buildings and the surrounding urban area heat to unnaturally high temperatures. It is hypothesized that extensive green roofs would have wide-ranging benefits for arid environments. However, little is known about the cost of water use associated with green roof installations and how to balance energy reduction needs with water costs in this water limited environment. We are conducting a pilot study to test whether a) green roofs with native plants and environmentally-responsible watering regimes will prove successful in arid environments and if b) green roofs provide ecosystem services with responsible water application. Three species of Sonoran Desert natives, Dyssodia pentachaeta (groundcover), Calliandra eriophylla (shrub), and Hesperaloe parviflora (succulent) have been planted in experimental plots [1 m2 model houses and roofs, replicated in triplicate] with two sandy, rocky desert soil mixtures (light mix: 60% expanded shale and heavy mix: organic and sandy mix with 50% shale) at the Biosphere 2 campus near Oracle, Az. The green roofs are watered by two different techniques. The first technique provides "smart watering", the minimal amount of water needed by green roof plants based on precipitation and historical data. The second watering technique is considered heavy and does not take into account environmental conditions. Preliminary data from the experimental plots shows a 30% decrease in daytime roof top temperatures on green roofs and a 10% decrease in interior temperatures in buildings with green roofs. This trend occurs with both watering regimes (heavy and light). This finding suggests that additional irrigation yields no extra heat reduction and energy savings. In order to explain this phenomenon more clearly, we use co-located temperature and soil moisture readings on each green roof to analyze the spatial and temporal covariance of water and temperature. We link these patterns in soil moisture to measures of plant performance with weekly hyperspectral images (NDVI - Normalized Difference Vegetation Index) of each green roof. The data will allow us to determine the minimal amount of water use required for successful green roofs and healthy green roof plants. Preliminary data from a five week pilot study in the 2011 summer monsoon has shown a variation in NDVI by species. H. parviflora displayed the highest NDVI values, while D. pentachaeta and C. eriophylla shared similar, lower NDVI values. In general, the comparison of soil moisture and NDVI values expressed a very weak positive relationship but stronger species specific responses. D. pentachaeta demonstrated the strongest response to soil water and H. parviflora displayed the weakest response.

Kovachich, S.; Pavao-Zuckerman, M.; Templer, S.; Livingston, M.; Stoltz, R.; Smith, S.

2011-12-01

27

Photovoltaic Roofs  

NASA Technical Reports Server (NTRS)

Solar cells perform two functions: waterproofing roof and generating electricity. Sections through horizontal and slanting joints show overlapping modules sealed by L-section rubber strips and side-by-side modules sealed by P-section strips. Water seeping through seals of slanting joints drains along channels. Rooftop photovoltaic array used watertight south facing roof, replacing shingles, tar, and gravel. Concept reduces cost of residential solar-cell array.

Drummond, R. W., Jr.; Shepard, N. F., Jr.

1984-01-01

28

Advanced Energy Efficient Roof System  

SciTech Connect

Energy consumption in buildings represents 40 percent of primary U.S. energy consumption, split almost equally between residential (22%) and commercial (18%) buildings.1 Space heating (31%) and cooling (12%) account for approximately 9 quadrillion Btu. Improvements in the building envelope can have a significant impact on reducing energy consumption. Thermal losses (or gains) from the roof make up 14 percent of the building component energy load. Infiltration through the building envelope, including the roof, accounts for an additional 28 percent of the heating loads and 16 percent of the cooling loads. These figures provide a strong incentive to develop and implement more energy efficient roof systems. The roof is perhaps the most challenging component of the building envelope to change for many reasons. The engineered roof truss, which has been around since 1956, is relatively low cost and is the industry standard. The roof has multiple functions. A typical wood frame home lasts a long time. Building codes vary across the country. Customer and trade acceptance of new building products and materials may impede market penetration. The energy savings of a new roof system must be balanced with other requirements such as first and life-cycle costs, durability, appearance, and ease of construction. Conventional residential roof construction utilizes closely spaced roof trusses supporting a layer of sheathing and roofing materials. Gypsum board is typically attached to the lower chord of the trusses forming the finished ceiling for the occupied space. Often in warmer climates, the HVAC system and ducts are placed in the unconditioned and otherwise unusable attic. High temperature differentials and leaky ducts result in thermal losses. Penetrations through the ceilings are notoriously difficult to seal and lead to moisture and air infiltration. These issues all contribute to greater energy use and have led builders to consider construction of a conditioned attic. The options considered to date are not ideal. One approach is to insulate between the trusses at the roof plane. The construction process is time consuming and costs more than conventional attic construction. Moreover, the problems of air infiltration and thermal bridges across the insulation remain. Another approach is to use structurally insulated panels (SIPs), but conventional SIPs are unlikely to be the ultimate solution because an additional underlying support structure is required except for short spans. In addition, wood spline and metal locking joints can result in thermal bridges and gaps in the foam. This study undertook a more innovative approach to roof construction. The goal was to design and evaluate a modular energy efficient panelized roof system with the following attributes: (1) a conditioned and clear attic space for HVAC equipment and additional finished area in the attic; (2) manufactured panels that provide structure, insulation, and accommodate a variety of roofing materials; (3) panels that require support only at the ends; (4) optimal energy performance by minimizing thermal bridging and air infiltration; (5) minimal risk of moisture problems; (6) minimum 50-year life; (7) applicable to a range of house styles, climates and conditions; (8) easy erection in the field; (9) the option to incorporate factory-installed solar systems into the panel; and (10) lowest possible cost. A nationwide market study shows there is a defined market opportunity for such a panelized roof system with production and semi-custom builders in the United States. Senior personnel at top builders expressed interest in the performance attributes and indicate long-term opportunity exists if the system can deliver a clear value proposition. Specifically, builders are interested in (1) reducing construction cycle time (cost) and (2) offering increased energy efficiency to the homebuyer. Additional living space under the roof panels is another low-cost asset identified as part of the study. The market potential is enhanced through construction activity levels in target marke

Jane Davidson

2008-09-30

29

THERMAL ?-? MODULATOR: PERFORMANCE ANALYSIS  

Microsoft Academic Search

This work presents the system performance analysis, in terms of frequency response and system resolution, of a 1-bit first-order ?-? thermal modulator. In this system model, some of the operations conversion is performed by the thermoresistive sensor, which operates at constant temperature method. The system performance analysis was realized with a sampled version of the continuous time thermal ?-? modulator.

L. S. Palma; A. Oliveira; R. C. S. Freire; A. B. Fontes

30

Roof pond systems  

SciTech Connect

This report provides a single-source document useful to architects, engineers, builders, and homeowners that addresses numerous aspects of roof pond design, construction, and performance. An introduction to the roof pond passive solar space heating and cooling concept is provided, including basic methods of operation and system configurations adaptable to different climates. A brief history of the development of the roof pond concept is presented, and several existing roof pond buildings located throughout the United States are described. The regional applicability of roof ponds in both heating and cooling service; design considerations relating to architecture, heating and cooling aspects, and structural requirements; and current heat transfer relations important in roof pond design are examined. A chapter on roof pond system materials and components is included. It contains tables of material properties; descriptions of available and installed components; installation, operation, and maintenance concerns; and a compilation of operating experience to date. The results of actual performance testing of several instrumented roof pond buildings are presented, and in certain cases, these results are compared with roof pond performance simulation results. A life-cycle cost study of two roof pond homes is developed, and the results are compared with the life-cycle costs of two similar conventional residences. This document has application to many related roof pond concepts, such as the Cool Pool and Energy Roof. An extensive bibliography is provided.

Marlatt, W.P.; Murray, K.A.; Squier, S.E.

1984-04-01

31

Evaluation of Vegetative Roofs' Performance on Energy Consumption in Hot and Humid Climates  

E-print Network

% and only 50% of its vegetative roof is covered with vegetation. A closer look at the type of plants used for both roofs shows that while the roof of Building (group4) mostly has sedum that of Building (group6) mostly has bushes. Figure 6... percentage of runoff reduction by the roof in comparison with the vegetative roof of Building (group 6) that has more vegetation coverage that consists of sedum. From the above analysis of the data on storm water runoff of the vegetative roofs...

Anderson, J.; Azarbayjani, M.

32

Plant performance on Mediterranean green roofs: interaction of species-specific hydraulic strategies and substrate water relations  

PubMed Central

Recent studies have highlighted the ecological, economic and social benefits assured by green roof technology to urban areas. However, green roofs are very hostile environments for plant growth because of shallow substrate depths, high temperatures and irradiance and wind exposure. This study provides experimental evidence for the importance of accurate selection of plant species and substrates for implementing green roofs in hot and arid regions, like the Mediterranean area. Experiments were performed on two shrub species (Arbutus unedo L. and Salvia officinalis L.) grown in green roof experimental modules with two substrates slightly differing in their water retention properties, as derived from moisture release curves. Physiological measurements were performed on both well-watered and drought-stressed plants. Gas exchange, leaf and xylem water potential and also plant hydraulic conductance were measured at different time intervals following the last irrigation. The substrate type significantly affected water status. Arbutus unedo and S. officinalis showed different hydraulic responses to drought stress, with the former species being substantially isohydric and the latter one anisohydric. Both A. unedo and S. officinalis were found to be suitable species for green roofs in the Mediterranean area. However, our data suggest that appropriate choice of substrate is key to the success of green roof installations in arid environments, especially if anisohydric species are employed. PMID:25603968

Raimondo, Fabio; Trifilò, Patrizia; Lo Gullo, Maria A.; Andri, Sergio; Savi, Tadeja; Nardini, Andrea

2015-01-01

33

Plant performance on Mediterranean green roofs: interaction of species-specific hydraulic strategies and substrate water relations.  

PubMed

Recent studies have highlighted the ecological, economic and social benefits assured by green roof technology to urban areas. However, green roofs are very hostile environments for plant growth because of shallow substrate depths, high temperatures and irradiance and wind exposure. This study provides experimental evidence for the importance of accurate selection of plant species and substrates for implementing green roofs in hot and arid regions, like the Mediterranean area. Experiments were performed on two shrub species (Arbutus unedo L. and Salvia officinalis L.) grown in green roof experimental modules with two substrates slightly differing in their water retention properties, as derived from moisture release curves. Physiological measurements were performed on both well-watered and drought-stressed plants. Gas exchange, leaf and xylem water potential and also plant hydraulic conductance were measured at different time intervals following the last irrigation. The substrate type significantly affected water status. Arbutus unedo and S. officinalis showed different hydraulic responses to drought stress, with the former species being substantially isohydric and the latter one anisohydric. Both A. unedo and S. officinalis were found to be suitable species for green roofs in the Mediterranean area. However, our data suggest that appropriate choice of substrate is key to the success of green roof installations in arid environments, especially if anisohydric species are employed. PMID:25603968

Raimondo, Fabio; Trifilò, Patrizia; Lo Gullo, Maria A; Andri, Sergio; Savi, Tadeja; Nardini, Andrea

2015-01-01

34

Evaluation of Green Roof Water Quantity and Quality Performance in an Urban Climate  

EPA Science Inventory

In this report we present an analysis of water benefits from an array of observed green roof and control (non-vegetated) roof project sites throughout NYC. The projects are located on a variety of building sites and represent a diverse set of available extensive green roof instal...

35

Predicting the Performance of Small Wind Turbines in the RoofTop Urban Environment  

Microsoft Academic Search

This paper summarises the results of computational fluid dynamics (CFD) and semi-empirical modelling to predict wind resource and expected output of small wind turbines mounted on building roofs within the urban environment. A number of configurations are considered including; different roof pitches, flat topped roofs, houses laid out in different street configurations and houses on slopes. An example calculation is

David Infield; Mark Harding

36

PERFORMANCE EVALUATION OF A SUSTAINABLE AND ENERGY EFFICIENT RE-ROOFING TECHNOLOGY USING FIELD-TEST DATA  

SciTech Connect

Three test attics were constructed to evaluate a new sustainable method of re-roofing utilizing photo-voltaic (PV) laminates, metal roofing panels, and PCM heat sink in the Envelope Systems Research Apparatus (ESRA) facility in the ORNL campus. Figure 1 is a picture of the three attic roofs located adjacent to each other. The leftmost roof is the conventional shingle roof, followed by the metal panel roof incorporating the cool-roof coating, and third from left is the roof with the PCM. On the PCM roof, the PV panels are seen as well; they're labelled from left-to-right as panels 5, 6 and 7. The metal panel roof consists of three metal panels with the cool-roof coating; in further discussion this is referred to as the infrared reflective (IRR) metal roof. The IRR metal panels reflect the incoming solar radiation and then quickly re-emit the remaining absorbed portion, thereby reducing the solar heat gain of the attic. Surface reflectance of the panels were measured using a Solar Spectrum Reflectometer. In the 0.35-2.0 {mu}m wavelength interval, which accounts for more than 94% of the solar energy, the IRR panels have an average reflectance of 0.303. In the infrared portion of the spectrum, the IRR panel reflectance is 0.633. The PCM roof consists of a layer of macro-encapsulated bio-based PCM at the bottom, followed by a 2-cm thick layer of dense fiberglass insulation with a reflective surface on top, and metal panels with pre-installed PV laminates on top. The PCM has a melting point of 29 C (84.2 F) and total enthalpy between 180 and 190 J/g. The PCM was macro-packaged in between two layers of heavy-duty plastic foil forming arrays of PCM cells. Two air cavities, between PCM cells and above the fiberglass insulation, helped the over-the-deck natural air ventilation. It is anticipated that during summer, this extra ventilation will help in reducing the attic-generated cooling loads. The extra ventilation, in conjunction with the PCM heat sink, are used to minimize thermal stresses due to the PV laminates on sunny days. In PV laminates sunlight is converted into electricity and heat simultaneous. In case of building integrated applications, a relatively high solar absorption of amorphous silicon laminates can be utilized during the winter for solar heating purposes with PCM providing necessary heat storage capacity. However, PV laminates may also generate increased building cooling loads during the summer months. Therefore, in this project, the PCM heat sink was to minimize summer heat gains as well. The PCM-fibreglass-PV assembly and the IRR metal panels are capable of being installed directly on top of existing shingle roofs during re-roofing, precluding the need for recycling or disposal of waste materials. The PV laminates installed on the PCM attic are PVL-144 models from Uni-Solar. Each laminate contains 22 triple junction amorphous silicon solar cells connected in series. The silicon cells are of dimensions 356 mm x 239 mm (14-in. x 9.4-in.). The PVL-144 laminate is encapsulated in durable ETFE (poly-ethylene-co-tetrafluoroethylene) high light-transmissive polymer. Table 1 lists the power, voltage and current ratings of the PVL-144 panel.

Biswas, Kaushik [ORNL; Miller, William A [ORNL; Childs, Phillip W [ORNL; Kosny, Jan [ORNL; Kriner, Scott [Metal Construction Association, Glenview, IL

2011-01-01

37

Effectiveness of Cool Roof Coatings with Ceramic Particles  

SciTech Connect

Liquid applied coatings promoted as cool roof coatings, including several with ceramic particles, were tested at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tenn., for the purpose of quantifying their thermal performances. Solar reflectance measurements were made for new samples and aged samples using a portable reflectometer (ASTM C1549, Standard Test Method for Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer) and for new samples using the integrating spheres method (ASTM E903, Standard Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres). Thermal emittance was measured for the new samples using a portable emissometer (ASTM C1371, Standard Test Method for Determination of Emittance of Materials Near Room 1 Proceedings of the 2011 International Roofing Symposium Temperature Using Portable Emissometers). Thermal conductivity of the coatings was measured using a FOX 304 heat flow meter (ASTM C518, Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus). The surface properties of the cool roof coatings had higher solar reflectance than the reference black and white material, but there were no significant differences among coatings with and without ceramics. The coatings were applied to EPDM (ethylene propylene diene monomer) membranes and installed on the Roof Thermal Research Apparatus (RTRA), an instrumented facility at ORNL for testing roofs. Roof temperatures and heat flux through the roof were obtained for a year of exposure in east Tennessee. The field tests showed significant reduction in cooling required compared with the black reference roof (~80 percent) and a modest reduction in cooling compared with the white reference roof (~33 percent). The coating material with the highest solar reflectivity (no ceramic particles) demonstrated the best overall thermal performance (combination of reducing the cooling load cost and not incurring a large heating penalty cost) and suggests solar reflectivity is the significant characteristic for selecting cool roof coatings.

Brehob, Ellen G [ORNL] [ORNL; Desjarlais, Andre Omer [ORNL] [ORNL; Atchley, Jerald Allen [ORNL] [ORNL

2011-01-01

38

IMPROVED ROOF STABILIZATION TECHNOLOGIES  

SciTech Connect

Many U.S. Department of Energy (DOE) remediation sites have performed roof repair and roof replacement to stabilize facilities prior to performing deactivation and decommissioning (D&D) activities. This project will review the decision criteria used by these DOE sites, along with the type of repair system used for each different roof type. Based on this information, along with that compiled from roofing experts, a decision-making tool will be generated to aid in selecting the proper roof repair systems. Where appropriate, innovative technologies will be reviewed and applied to the decision-making tool to determine their applicability. Based on the results, applied research and development will be conducted to develop a method to repair these existing roofing systems, while providing protection for the D and D worker in a cost-efficient manner.

M.A. Ebadian, Ph.D.

1999-01-01

39

Rain on the Roof-Evaporative Spray Roof Cooling  

E-print Network

-air principles are covered and a simplified method of evaluation presented. A life cycle energy savings example is discussed. Benefits of roof life and roof top equipment efficiency and maintenance are covered as well as water consumption and performance trade...

Bachman, L. R.

1985-01-01

40

Performance of powder-filled evacuated panel insulation in a manufactured home roof cavity: Tests in the Large Scale Climate Simulator  

SciTech Connect

A full-scale section of half the top of a single-wide manufactured home has been studied in the Large Scale Climate Simulator (LSCS) at the Oak Ridge National Laboratory. A small roof cavity with little room for insulation at the eaves is often the case with single-wide units and limits practical ways to improve thermal performance. The purpose of the current tests was to obtain steady-state performance data for the roof cavity of the manufactured home test section when the roof cavity was insulated with fiberglass batts, blown-in rock wool insulation or combinations of these insulations and powder-filled evacuated panel (PEP) insulation. Four insulation configurations were tested: (A) a configuration with two layers of nominal R{sub US}-7 h {center_dot} ft{sup 2} {center_dot} F/BTU (R{sub SI}-1.2 m{sup 2} {center_dot} K/W) fiberglass batts; (B) a layer of PEPs and one layer of the fiberglass batts; (C) four layers of the fiberglass batts; and (D) an average 4.1 in. (10.4 cm) thick layer of blown-in rock wool at an average density of 2.4 lb/ft{sup 3} (38 kg/m{sup 3}). Effects of additional sheathing were determined for Configurations B and C. With Configuration D over the ceiling, two layers of expanded polystyrene (EPS) boards, each about the same thickness as the PEPs, were installed over the trusses instead of the roof. Aluminum foils facing the attic and over the top layer of EPS were added. The top layer of EPS was then replaced by PEPs.

Petrie, T.W.; Kosny, J.; Childs, P.W.

1996-03-01

41

Research on the Effect of a Planting Roof on the Thermal Load of a Business Building  

E-print Network

of indoor air temperature within the average day 8 10 12 14 16 1815 20 25 30 35 40 45 50 55 to( ) toso( ) tosp( ) time temperature( ) Fig.5 The variation of outer surface temperature of the roof within the average day ICEBO2006, Shenzhen, China...

Zhang, W.; Wu, J.; Wei, Y.; Gao, X.

2006-01-01

42

Performance and Thermal Comfort  

Microsoft Academic Search

This experiment attempts to establish an objective measure of thermal comfort. A theoretical explanation of the relationship between performance and comfort is given and is represented in terms of an hypothesis. A total of 50 subjects was divided among five groups, each group experiencing one temperature in the range 15.6-26.7°C (60-80°F) for both air and surfaces. Each subject was placed

I. D. GRIFFITHS; P. R. BOYCE

1971-01-01

43

PERFORMANCE EVALUATION OF A SUSTAINABLE AND ENERGY EFFICIENT RE-ROOFING TECHNOLOGY USING FIELD-TEST DATA  

Microsoft Academic Search

Three test attics were constructed to evaluate a new sustainable method of re-roofing utilizing photo-voltaic (PV) laminates, metal roofing panels, and PCM heat sink in the Envelope Systems Research Apparatus (ESRA) facility in the ORNL campus. Figure 1 is a picture of the three attic roofs located adjacent to each other. The leftmost roof is the conventional shingle roof, followed

Kaushik Biswas; William A Miller; Phillip W Childs; Jan Kosny; Scott Kriner

2011-01-01

44

Investigating and analysing the energy and environmental performance of an experimental green roof system installed in a nursery school building in Athens, Greece  

Microsoft Academic Search

This paper deals with the experimental investigation and analysis of the energy and environmental performance of a green roof system installed in a nursery school building in Athens. The investigation was implemented in two phases. During the first phase, an experimental investigation of the green roof system efficiency was presented and analysed, while in the second one the energy savings

M. Santamouris; C. Pavlou; P. Doukas; G. Mihalakakou; A. Synnefa; A. Hatzibiros; P. Patargias

2007-01-01

45

Thermal Performance Benchmarking (Presentation)  

SciTech Connect

This project will benchmark the thermal characteristics of automotive power electronics and electric motor thermal management systems. Recent vehicle systems will be benchmarked to establish baseline metrics, evaluate advantages and disadvantages of different thermal management systems, and identify areas of improvement to advance the state-of-the-art.

Moreno, G.

2014-11-01

46

Thermal Performance of Uninsulated and Partially Filled Wall Cavities: Preprint  

SciTech Connect

Low-rise, wood-framed homes are the most common type of residential structures in the United States. Wood wall construction supports roofs efficiently and provides a stable frame for attaching interior and exterior wall coverings. Wall cavities are prevalent and increase thermal resistance, particularly when they are filled with insulating material. This paper describes detailed computational fluid dynamics modeling to evaluate the thermal performance of uninsulated or partially filled wall cavities and accounts for conduction through framing, convection, and radiation. Parameters are ambient outdoor temperature, cavity surface emissivity, cavity aspect ratio, and insulation height. Understanding the thermal performance of uninsulated or partially insulated wall cavities is essential for conserving energy in residential buildings. The results can serve as input for building energy simulation tools such as DOE2 and EnergyPlus for modeling the temperature dependent energy performance of new and older homes with uninsulated or partially insulated walls.

Ridouane, E. H.; Bianchi, M.

2011-08-01

47

Sustainable roofs with real energy savings  

SciTech Connect

This paper addresses the general concept of sustainability and relates it to the building owner`s selection of a low-slope roof. It offers a list of performance features of sustainable roofs. Experiences and data relevant to these features for four unique roofs are then presented which include: self-drying systems, low total equivalent warming foam insulation, roof coatings and green roofs. The paper concludes with a list of sustainable roofing features worth considering for a low-slope roof investment. Building owners and community developers are showing more interest in investing in sustainability. The potential exists to design, construct, and maintain roofs that last twice as long and reduce the building space heating and cooling energy loads resulting from the roof by 50% (based on the current predominant design of a 10-year life and a single layer of 1 to 2 in. (2.5 to 5.1 cm) of insulation). The opportunity to provide better low-slope roofs and sell more roof maintenance service is escalating. The general trend of outsourcing services could lead to roofing companies` owning the roofs they install while the traditional building owner owns the rest of the building. Such a situation would have a very desirable potential to internalize the costs of poor roof maintenance practices and high roof waste disposal costs, and to offer a profit for installing roofs that are more sustainable. 14 refs., 12 figs.

Christian, J.E.; Petrie, T.W.

1996-12-31

48

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. Additional field tests have been performed. It is found that the drilling power can be used as a supplementary method for detecting voids/fractures and rock interfaces.

Syd S. Peng

2003-01-15

49

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. More field tests have been performed. A trendline analysis method has been developed. This method would improve the accuracy in detecting the locations of fractures and in determining the rock strength.

Syd S. Peng

2003-04-15

50

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. Additional field tests have been performed in this quarter. The development of the data interpretation methodology and other related tasks are still continuing.

Syd S. Peng

2002-10-15

51

Bright is the New Black - Multi-Year Performance of Generic High-Albedo Roofs in an Urban Climate  

NASA Technical Reports Server (NTRS)

High-albedo white and cool roofing membranes are recognized as a fundamental strategy that dense urban areas can deploy on a large scale, at low cost, to mitigate the urban heat island effect. We are monitoring three generic white membranes within New York City that represent a cross-section of the dominant white membrane options for U.S. flat roofs: (1) an ethylene propylene diene monomer (EPDM) rubber membrane; (2) a thermoplastic polyolefin (TPO) membrane and; (3) an asphaltic multi-ply built-up membrane coated with white elastomeric acrylic paint. The paint product is being used by New York City s government for the first major urban albedo enhancement program in its history. We report on the temperature and related albedo performance of these three membranes at three different sites over a multi-year period. The results indicate that the professionally installed white membranes are maintaining their temperature control effectively and are meeting the Energy Star Cool Roofing performance standards requiring a three-year aged albedo above 0.50. The EPDM membrane however shows evidence of low emissivity. The painted asphaltic surface shows high emissivity but lost about half of its initial albedo within two years after installation. Given that the acrylic approach is an important "do-it-yourself," low-cost, retrofit technique, and, as such, offers the most rapid technique for increasing urban albedo, further product performance research is recommended to identify conditions that optimize its long-term albedo control. Even so, its current multi-year performance still represents a significant albedo enhancement for urban heat island mitigation.

Gaffin, S. R.; Imhoff, M.; Rosenzweig, C.; Khanbilvardi, R.; Pasqualini, A.; Kong, A. Y. Y.; Grillo, D.; Freed, A.; Hillel, D.; Hartung, E.

2012-01-01

52

Integrated Modelling and Performance Analysis of Green Roof Technologies in Urban Environments  

NASA Astrophysics Data System (ADS)

As a result of the changing global climate and increase in urbanisation, the behaviour of the urban environment has been significantly altered, causing an increase in both the frequency of extreme weather events, such as flooding and drought, and also the associated costs. Moreover, uncontrolled or inadequately planned urbanisation can exacerbate the damage. The Blue-Green Dream (BGD) project therefore develops a series of components for urban areas that link urban vegetated areas (green infrastructure) with existing urban water (blue) systems, which will enhance the synergy of urban blue and green systems and provide effective, multifunctional BGD solutions to support urban adaptation to future climatic changes. Coupled with new urban water management technologies and engineering, multifunctional benefits can be gained. Some of the technologies associated with BGD solutions include green roofs, swales that might deal with runoff more effectively and urban river restoration that can produce benefits similar to those produced from sustainable urban drainage systems (SUDS). For effective implementation of these technologies, however, appropriate tools and methodologies for designing and modelling BGD solutions are required to be embedded within urban drainage models. Although several software packages are available for modelling urban drainage, the way in which green roofs and other BGD solutions are integrated into these models is not yet fully developed and documented. This study develops a physically based mass and energy balance model to monitor, test and quantitatively evaluate green roof technology for integrated BGD solutions. The assessment of environmental benefits will be limited to three aspects: (1) reduction of the total runoff volume, (2) delay in the initiation of runoff, and (3) reduction of building energy consumption, rather than water quality, visual, social or economic impacts. This physically based model represents water and heat dynamics in a layered soil profile covered with vegetation which can be used to simulate the physical behaviour of different green roof systems in response to rainfall under various climatic conditions. Because it is a physically based model, this model could be generalised to other atmosphere-plant-soil systems. The validity of this mass and energy balance approach will be demonstrated by comparing its outcomes with observations from a green roof experimental site in London, UK.

Liu, Xi; Mijic, Ana; Maksimovic, Cedo

2014-05-01

53

Structural stability vs. thermal performance: old dilemma, new solutions  

SciTech Connect

In many building envelopes, actual thermal performance falls quite a bit short of nominal design parameters given in standards. Very often only windows, doors, and a small part of the wall area meet standards requirements. In the other parts of the building envelope, unaccounted thermal bridges reduce the effective thermal resistance of the insulation material. Such unaccounted heat losses compromise the thermal performance of the whole building envelope. For the proper analysis of the thermal performance of most wall and roof details, measurements and three-dimensional thermal modeling are necessary. For wall thermal analysis the whole-wall R-value calculation method can be very useful. In ties method thermal properties of all wall details are incorporated as an area weighted average. For most wall systems, the part of the wall that is traditionally analyzed, is the clear wall, that is, the flat part of the wall that is uninterrupted by details. It comprises only 50 to 80% of the total area of the opaque wall. The remaining 20 to 50% of the wall area is not analyzed nor are its effects incorporated in the thermal performance calculations. For most of the wall technologies, traditionally estimated R-values are 20 to 30% higher than whole-wall R-values. Such considerable overestimation of wall thermal resistance leads to significant errors in building heating and cooling load estimations. In this paper several examples are presented of the use of the whole-wall R-value procedure for building envelope components. The advantages of the use of the whole wall R-value calculation procedure are also discussed. For several building envelope components, traditional clear-wall R-values are compared with the results of whole-wall thermal analysis to highlight significant limits on the use of the traditional methods and the advantages of advanced computer modeling.

Kosny, J.; Christian, J.E.

1996-10-01

54

Roof Plans: Section "CC", Roof Plan; Roof Framing Plans: Section ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Roof Plans: Section "C-C", Roof Plan; Roof Framing Plans: Section "C-C", Section "D-D"; Roof Framing Sections: Cross Section "G-G", Cross Section "H-H" - Fort Washington, Fort Washington Light, Northeast side of Potomac River at Fort Washington Park, Fort Washington, Prince George's County, MD

55

ROOF GARDENS IN BRAZIL  

Microsoft Academic Search

The green roof technology has its origin in several different countries and in various climates. Green roofs have become an important element of sustainable architecture. Actually green roofs are spreading out worldwide (1,2). Green roofs can be divided into three categories: • Spontaneous green roofs • Extensive green light weight roofs with low maintenance, without additional irrigation and fertilizing. •

Manfred Köhler; Marco Schmidt; Michael Laar

56

Combating the Urban Heat Island Effect: Results from a Long-Term Monitoring Study on Urban Green, White, and Black Roofs in New York City  

NASA Astrophysics Data System (ADS)

Urban heat island mitigation strategies include increasing urban vegetation and increasing the albedo of impervious surfaces. Vegetated "green" roofs can provide benefits to stormwater management, water quality, energy cost efficiency, and biodiversity in cities, but the body of research on green roofs in the US is not large and cities in the US have been slow to adopt green roofs. On the other hand, "high-albedo" white roofs have been applied more widely through projects such as New York City Cool Roofs. There are several major issues (e.g., albedo decline, product differences, and long-term temperature controls) about green and white roof performance versus typical black roofs with respect to urban heat island mitigation that have yet to be fully addressed. Here, we present data from an on-going, long-term study in New York City in which pilot, urban albedo enhancement and vegetation effects have been monitored at the building-scale since 2007. Although the urban heat island effect can be detected throughout the year, our objective for this paper was to compare green roof vegetation with those of the high-albedo roofs for their ability to reduce the electricity demand for cooling in the summer. Using energy balance methodology across our sites (three), we found that green and white roof membrane temperature peaks are on average 60°F (33°C) and 30° F (17°C), respectively, cooler than black roof temperature peaks, and that these alternative surfaces significantly reduce thermal stress to roof membranes. Interestingly, we found that industrial white membranes [thermoplastic polyolefin (TPO) and ethylene propylene diene monomer (EPDM)] stay cleaner longer, thereby, maintaining the high-albedo benefits longer than the painted roofs, which tend to lose their albedo properties rapidly. Results thus far suggest that more long-term research comparing the albedo and cooling benefits of green and white roofs to black roofs is necessary to understand temporal changes to roof performance.

Gaffin, S. R.; Kong, A. Y.; Hartung, E.; Hsu, B.; Roditi, A.; Rosenzweig, C.

2011-12-01

57

Evaluation of Roof Bolting Requirements Based on In-Mine Roof Bolter Drilling  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on this information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. For the prediction of roof geology and stability condition in real time, a micro processor was used and a program developed to monitor and record the drilling parameters of roof bolter. These parameters include feed pressure, feed flow (penetration rate), rotation pressure, rotation rate, vacuum pressure, oil temperature of hydraulic circuit, and signals for controlling machine. From the results of a series of laboratory and underground tests so far, feed pressure is found to be a good indicator for identifying the voids/fractures and estimating the roof rock strength. The method for determining quantitatively the location and the size of void/fracture and estimating the roof rock strength from the drilling parameters of roof bolter was developed. Also, a set of computational rules has been developed for in-mine roof using measured roof drilling parameters and implemented in MRGIS (Mine Roof Geology Information System), a software package developed to allow mine engineers to make use of the large amount of roof drilling parameters for predicting roof geology properties automatically. For the development of roof bolting criteria, finite element models were developed for tensioned and fully grouted bolting designs. Numerical simulations were performed to investigate the mechanisms of modern roof bolting systems including both the tension and fully grouted bolts. Parameters to be studied are: bolt length, bolt spacing, bolt size/strength, grout annulus, in-situ stress condition, overburden depth, and roof geology (massive strata, fractured, and laminated or thinly-bedded). Based on the analysis of the mechanisms of both bolting systems and failure modes of the bolted strata, roof bolting design criteria and programs for modern roof bolting systems were developed. These criterion and/or programs were combined with the MRGIS for use in conjunction with roof bolt installation.

Syd S. Peng

2005-10-01

58

Development of a Roof Savings Calculator  

SciTech Connect

A web-based Roof Savings Calculator (RSC) has been deployed for the Department of Energy as an industry-consensus tool to help building owners, manufacturers, distributors, contractors and researchers easily run complex roof and attic simulations. This tool employs the latest web technologies and usability design to provide an easy input interface to an annual simulation of hour-by-hour, whole-building performance using the world-class simulation tools DOE-2.1E and AtticSim. Building defaults were assigned and can provide annual energy and cost savings after the user selects nothing more than building location. In addition to cool reflective roofs, the RSC tool can simulate multiple roof types at arbitrary inclinations. There are options for above sheathing ventilation, radiant barriers and low-emittance surfaces. The tool also accommodates HVAC ducts either in the conditioned space or in the attic with custom air leakage rates. Multiple layers of thermal mass, ceiling insulation and other parameters can be compared side-by-side to generate energy/cost savings between two buildings. The RSC tool was benchmarked against field data for demonstration homes in Ft Irwin, CA.

New, Joshua Ryan [ORNL] [ORNL; Miller, William A [ORNL] [ORNL; Huang, Joe [Lawrence Berkeley National Laboratory (LBNL)] [Lawrence Berkeley National Laboratory (LBNL); Erdem, Ender [Lawrence Berkeley National Laboratory (LBNL)] [Lawrence Berkeley National Laboratory (LBNL)

2011-01-01

59

Green roofs: potential at LANL  

SciTech Connect

Green roofs, roof systems that support vegetation, are rapidly becoming one of the most popular sustainable methods to combat urban environmental problems in North America. An extensive list of literature has been published in the past three decades recording the ecological benefits of green roofs; and now those benefits have been measured in enumerated data as a means to analyze the costs and returns of green roof technology. Most recently several studies have made substantial progress quantifying the monetary savings associated with storm water mitigation, the lessoning of the Urban Heat Island, and reduction of building cooling demands due to the implementation of green roof systems. Like any natural vegetation, a green roof is capable of absorbing the precipitation that falls on it. This capability has shown to significantly decrease the amount of storm water runoff produced by buildings as well as slow the rate at which runoff is dispensed. As a result of this reduction in volume and velocity, storm drains and sewage systems are relieved of any excess stress they might experience in a storm. For many municipalities and private building owners, any increase in storm water mitigation can result in major tax incentives and revenue that does not have to be spent on extra water treatments. Along with absorption of water, vegetation on green roofs is also capable of transpiration, the process by which moisture is evaporated into the air to cool ambient temperatures. This natural process aims to minimize the Urban Heat Island Effect, a phenomenon brought on by the dark and paved surfaces that increases air temperatures in urban cores. As the sun distributes solar radiation over a city's area, dark surfaces such as bitumen rooftops absorb solar rays and their heat. That heat is later released during the evening hours and the ambient temperatures do not cool as they normally would, creating an island of constant heat. Such excessively high temperatures induce heat strokes, heat exhaustion, and pollution that can agitate the respiratory system. The most significant savings associated with green roofs is in the reduction of cooling demands due to the green roof's thermal mass and their insulating properties. Unlike a conventional roof system, a green roof does not absorb solar radiation and transfer that heat into the interior of a building. Instead the vegetation acts as a shade barrier and stabilizes the roof temperature so that interior temperatures remain comfortable for the occupants. Consequently there is less of a demand for air conditioning, and thus less money spent on energy. At LANL the potential of green roof systems has already been realized with the construction of the accessible green roof on the Otowi building. To further explore the possibilities and prospective benefits of green roofs though, the initial capital costs must be invested. Three buildings, TA-03-1698, TA-03-0502, and TA-53-0031 have all been identified as sound candidates for a green roof retrofit project. It is recommended that LANL proceed with further analysis of these projects and implementation of the green roofs. Furthermore, it is recommended that an urban forestry program be initiated to provide supplemental support to the environmental goals of green roofs. The obstacles barring green roof construction are most often budgetary and structural concerns. Given proper resources, however, the engineers and design professionals at LANL would surely succeed in the proper implementation of green roof systems so as to optimize their ecological and monetary benefits for the entire organization.

Pacheco, Elena M [Los Alamos National Laboratory

2009-01-01

60

Thesis Title : Field Comparative Analysis of Thermal Performance of a Solar Chimney Ventilated House with Common House  

Microsoft Academic Search

The thesis presents a comparative study of thermal performance of solar chimney (SC) house compared to a common house. The SC house is a common conventional one that was modified (retrofit) by integrating roof solar collector (RSC) and modified trombe wall (MTW) units. The RSC is facing due east and west whereas the wall is facing due south. The surface

Joseph Khedari

61

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. The retrofitting works for a dedicated roof bolter for this research has been completed. The laboratory tests performed using this machine on simulated roof blocks have been conducted. The analysis performed on the testing data showed promising signs to detect the rock interface, fractures, as well as the rock types. The other tasks were progressing as planned.

Syd S. Peng

2001-10-15

62

Radiation control coatings installed on rough-surfaced built-up roofs -- Initial results  

SciTech Connect

The authors have tracked the solar reflectance and thermal performance of small samples of various radiation control coatings on smooth surfaces for several years on a roof test facility in East Tennessee. The focus is on white coatings because of their potential to weather, causing the solar reflectance to decrease as the coatings age. Support of the federal New Technology Demonstration Program allowed them to extend the study to more samples on smooth surfaces and entire rough-surfaced roofs at a federal facility in the Panhandle of Florida. Two rough-surfaced, moderately well-insulated, low solar reflectance built-up roofs (BURs) were spray-coated with a latex-based product with ceramic beads added to improve solar reflectance. In the first three months after installation, the fresh BUR coatings showed a significant decrease in both the outside-surface temperature and the heat flux through the roof insulation. Average sunlit values were generated to exclude nighttime data, data on cloudy days, and data when the uncoated patch on one roof was more strongly shaded in mid-afternoon on sunny days. The average power demand during occupied periods for the first month with the coating for the building with the thermally massive roof deck was 13% less than during the previous month without the coating. For the other buildings with a lightweight roof deck but high internal loads, there were no clear average power savings due to the coating. The authors are continuing to monitor electricity use in these all-electric buildings to calibrate a model for the peak power and annual energy use of the buildings. Modeling results to be given at the end of the two year project will address the effect of roof R-value, geographic location, and solar reflectance, including the effect of weathering, on the performance of coated roofs. The calibrated models should allow one to segregate site-specific effects such as shading and large thermal mass.

Petrie, T.W.; Childs, P.W.; Christian, J.E.

1998-01-01

63

Hydrological Response of Sedum-Moss Roof  

NASA Astrophysics Data System (ADS)

Eco-roofs are becoming popular for aesthetic reasons and also as units of stormwater systems. It is thought that such roofs with soil cover and vegetation reduces the total runoff, the peak flows and improves the quality of the roof water. Here are reported investigations of runoff from thin, 3-4 cm soil, extensive green roofs with sedum-moss in southern Sweden. The two-year study was performed on new roofs in the eco-city Augustenborg and also on nearby old vegetative roofs. The rain intensity and the roof runoff were measured with 5 min, or in some experiments with 1 min, resolution. The annual runoff from the eco-roofs was about half that from hard roofs and was close to that of small natural rivers. However, although most rainy days there was no or little runoff from the roofs, the highest observed daily runoff values were close to the daily rainfall. Runoff is initiated, when the soil is at field capacity. Thereafter the hourly runoff corresponds closely to the hourly rainfall. For short-term high intensity storms, the runoff peak is attenuated relative the rain intensity. The time of concentration for runoff was experimentally determined applying artificial rains on existing roofs and on experimental roof plots with varying slopes and using different drainage layers. The peak runoff from the roofs was found to correspond to the rain intensity over 20-30 minutes. The probability of high rain intensity is much higher than the probability of high runoff. When intensity-duration-frequency curves were constructed, runoff with 0.4 year return period corresponded to rain with 1.5 year return period. The influence of the slope of the roofs on the runoff peak was minor as was the effect of drainage layer. The vertical flow in the soil dominates the runoff process. The influence of extensive sedum-moss vegetated roofs on runoff quality was also studied to ascertain whether vegetated roofs behave as sink or source of pollutants and whether the runoff quality changes with roof age. The results show that in general vegetated roofs behave as a source of contaminants. With the exception of a 15-year old roof, the studied vegetated roofs contributed phosphate-phosphorus to the runoff. Some metals appeared in concentrations that corresponds to moderately polluted water. However, nitrate-nitrogen is retained by the vegetation and the soil.

Bengtsson, L.

2004-12-01

64

Roof shading and wall glazing techniques for reducing peak building heating and cooling loads. Final report  

Microsoft Academic Search

The roof shading device proved to be effective in reducing peak building cooling loads under both actual testing conditions and in selected computer simulations. The magnitude of cooling load reductions varied from case to case depending on individual circumstances. Key variables that had significant impacts on its thermal performance were the number of months of use annually, the thermal characteristics

Ueland

1981-01-01

65

Thermal Performance of Uninsulated and Partially Filled Wall Cavities  

SciTech Connect

Wall cavities are widely present in the construction of low rise homes since wood framing is the most common type of construction for residential buildings in the United States. The primary function of such wall construction is to provide a stable frame to which interior and exterior wall coverings can be attached and by which a roof can be supported. The existence of wall cavities increases the thermal resistance of the enclosure, particularly when they are filled with insulating material. Several design guides provide data for prediction of the thermal resistance of uninsulated wall cavities of varying internal geometries. However, U-value coefficients provided in these guides do not account for partially insulated cavities or for variations in aspect ratio. Whole building energy simulation tools, like DOE2 or Energy Plus, use simplified, 1-D characterization of building envelopes. For the most part, this characterization assumes a fixed thermal resistance over the range of temperatures experienced by the enclosure. In reality, the thermal resistance is dominated by convection and radiation and is a function of several parameters, including the temperatures and emissivities of the cavity surfaces and the aspect ratio of the cavity. This study describes detailed CFD modeling to evaluate the thermal performance of uninsulated or partially filled wall cavities accounting for conduction through framing, convection, and radiation. The resulting correlations can serve as input for DOE2 and Energy Plus modeling of older homes, where the walls are either uninsulated or partially insulated due to the settling of the insulating material. Parameters of the study are the ambient temperature outdoors, emissivity of the cavity surfaces, cavity aspect ratio, and height of the insulation level. The outcomes of this study provide: An understanding of the thermal performance of uninsulated or partially insulated wall cavities, which is an essential aspect of energy conservation in residential buildings. Accurate input for whole building simulations models like DOE2 and Energy Plus in various climate zones. Recommendations on retrofit measures.

Ridouane, E.H.; Bianchi, M. V. A.

2011-01-01

66

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The selected site and the field testing plan enabled us to test all three aspects of roof geological features. The development of the data interpretation methodologies and the geology mapping computer program have also been preceding well.

Syd S. Peng

2003-07-15

67

SPC12-301: Thermal performances of solar energy absorbers  

Microsoft Academic Search

The testing scheme applies to the case of absorbers where the heat carrier is a liquid passing from a single inlet to a single outlet. The absorbers are intended as part of a roof and must be tested in a standardized construction. Thermal efficiency, losses and the influence of the angle of incidence are discussed. The total solar flux in

H. E. B. Andersson; H. E. B

1979-01-01

68

Occupant Dynamics in Rollover Crashes: Influence of Roof Deformation and Seat Belt Performance on Probable Spinal Column Injury  

PubMed Central

Motor vehicle crashes are the leading cause of death in the United States for people ages 3–33, and rollover crashes have a higher fatality rate than any other crash mode. At the request and under the sponsorship of Ford Motor Company, Autoliv conducted a series of dynamic rollover tests on Ford Explorer sport utility vehicles (SUV) during 1998 and 1999. Data from those tests were made available to the public and were analyzed in this study to investigate the magnitude of and the temporal relationship between roof deformation, lap–shoulder seat belt loads, and restrained anthropometric test dummy (ATD) neck loads. During each of the three FMVSS 208 dolly rollover tests of Ford Explorer SUVs, the far-side, passenger ATDs exhibited peak neck compression and flexion loads, which indicated a probable spinal column injury in all three tests. In those same tests, the near-side, driver ATD neck loads never predicted a potential injury. In all three tests, objective roof/pillar deformation occurred prior to the occurrence of peak neck loads (Fz, My) for far-side, passenger ATDs, and peak neck loads were predictive of probable spinal column injury. The production lap and shoulder seat belts in the SUVs, which restrained both driver and passenger ATDs, consistently allowed ATD head contact with the roof while the roof was contacting the ground during this 1000 ms test series. Local peak neck forces and moments were noted each time the far-side, passenger ATD head contacted (“dived into”) the roof while the roof was in contact with the ground; however, the magnitude of these local peaks was only 2–13% of peak neck loads in all three tests. “Diving-type” neck loads were not predictive of injury for either driver or passenger ATD in any of the three tests. PMID:17641975

Cochran, John E.; King, Dottie; Burke, Donald S.

2007-01-01

69

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. More laboratory tests have been performed in this quarter. The analysis performed on the testing data showed: (1) abnormal rotational accelerations can be used as the indicator of the rock interfaces, and (2) the sharp drops of drilling thrust and torque agree well with the locations of fractures.

Syd S. Peng

2002-04-15

70

Orbital dystopia due to orbital roof defect.  

PubMed

We performed a retrospective review of patients who presented with delayed dystopia as a consequence of an orbital roof defect due to fractures and nontraumatic causes to search for a correlation between orbital roof defect size and surgical indications for the treatment thereof. Retrospective analyses were performed in 7 patients, all of whom presented with delayed dystopia due to orbital roof defects, between January 2001 and June 2011. The causes of orbital roof defects were displaced orbital roof fractures (5 cases), tumor (1 case), and congenital sphenoid dysplasia (1 case). All 7 patients had initially been treated conservatively and later presented with significant dystopia. The sizes of the defects were calculated on computed tomographic scans. Among the 7 patients, aspiration of cerebrospinal fluid, which caused ocular symptoms, in 1 patient with minimal displaced orbital roof and reconstruction with calvarial bone, titanium micromesh, or Medpor in 6 other patients were performed. The minimal size of the orbital roof in patients who underwent orbital roof reconstruction was 1.2 cm (defect height) x 1.0 cm (defect length), 0.94 cm(2). For all patients with orbital dystopia, displacement of the globe was corrected without any complications, regardless of whether the patient was evaluated grossly or by radiology. In this retrospective study, continuous monitoring of clinical signs and active surgical management should be considered for cases in which an orbital roof defect is detected, even if no definite symptoms are noted, to prevent delayed sequelae. PMID:24163861

Rha, Eun Young; Joo, Hong Sil; Byeon, Jun Hee

2013-01-01

71

Inclusion of cool roofs in nonresidential Title 24 prescriptive requirements  

SciTech Connect

Roofs that have high solar reflectance (high ability to reflect sunlight) and high thermal emittance (high ability to radiate heat) tend to stay cool in the sun. The same is true of low-emittance roofs with exceptionally high solar reflectance. Substituting a cool roof for a noncool roof tends to decrease cooling electricity use, cooling power demand, and cooling-equipment capacity requirements, while slightly increasing heating energy consumption. Cool roofs can also lower the ambient air temperature in summer, slowing ozone formation and increasing human comfort. DOE-2.1E building energy simulations indicate that use of a cool roofing material on a prototypical California nonresidential building with a low-sloped roof yields average annual cooling energy savings of approximately 300 kWh/1000 ft2 [3.2 kWh/m2], average annual natural gas deficits of 4.9 therm/1000 ft2 [5.6 MJ/m2], average source energy savings of 2.6 MBTU/1000 ft2 [30 MJ/m2], and average peak power demand savings of 0. 19 kW/1000 ft2 [2.1 W/m2]. The 15-year net present value (NPV) of energy savings averages $450/1000 ft2 [$4.90/m2] with time dependent valuation (TDV), and $370/1000 ft2 [$4.00/m2] without TDV. When cost savings from downsizing cooling equipment are included, the average total savings (15-year NPV + equipment savings) rises to $550/1000 ft2 [$5.90/m2] with TDV, and to $470/1000 ft2 [$5.00/m2] without TDV. Total savings range from 0.18 to 0.77 $/ft2 [1.90 to 8.30 $/m2] with TDV, and from 0.16 to 0.66 $/ft2 [1.70 to 7.10 $/m2] without TDV, across California's 16 climate zones. The typical cost premium for a cool roof is 0.00 to 0.20 $/ft2 [0.00 to 2.20 $/m2]. Cool roofs with premiums up to $0.20/ft2 [$2.20/m2] are expected to be cost effective in climate zones 2 through 16; those with premiums not exceeding $0.18/ft2 [$1.90/m2] are expected to be also cost effective in climate zone 1. Hence, this study recommends that the year-2005 California building energy efficiency code (Title 24, Pa rt 6 of the California Code of Regulations) for nonresidential buildings with low-sloped roofs include a cool-roof prescriptive requirement in all California climate zones. Buildings with roofs that do not meet prescriptive requirements may comply with the code via an ''overall-envelope'' approach (non-metal roofs only), or via a performance approach (all roof types).

Levinson, Ronnen; Akbari, Hashem; Konopacki, Steve; Bretz, Sarah

2002-12-15

72

Thermal and other tests of photovoltaic modules performed in natural sunlight  

NASA Technical Reports Server (NTRS)

The nominal operating cell temperature (NOCT), an effective way to characterize the thermal performance of a photovoltaic module in natural sunlight, is developed. NOCT measurements for more than twenty different modules are presented. Changes in NOCT reflect changes in module design, residential roof mounting, and dirt accumulation. Other test results show that electrical performance is improved by cooling modules with water and by use of a phase change wax. Electrical degradation resulting from the marriage of photovoltaic and solar water heating modules is demonstrated. Cost-effectiveness of each of these techniques is evaluated.

Stultz, J. W.

1979-01-01

73

Impact of Sustainable Cool Roof Technology on Building Energy Consumption  

NASA Astrophysics Data System (ADS)

Highly reflective roofing systems have been analyzed over several decades to evaluate their ability to meet sustainability goals, including reducing building energy consumption and mitigating the urban heat island. Studies have isolated and evaluated the effects of climate, surface reflectivity, and roof insulation on energy savings, thermal load mitigation and also ameliorating the urban heat island. Other sustainable roofing systems, like green-roofs and solar panels have been similarly evaluated. The motivation for the present study is twofold: the first goal is to present a method for simultaneous evaluation and inter-comparison of multiple roofing systems, and the second goal is to quantitatively evaluate the realized heating and cooling energy savings associated with a white roof system compared to the reduction in roof-top heat flux. To address the first research goal a field experiment was conducted at the International Harvester Building located in Portland, OR. Thermal data was collected for a white roof, vegetated roof, and a solar panel shaded vegetated roof, and the heat flux through these roofing systems was compared against a control patch of conventional dark roof membrane. The second research goal was accomplished using a building energy simulation program to determine the impact of roof area and roof insulation on the savings from a white roof, in both Portland and Phoenix. The ratio of cooling energy savings to roof heat flux reduction from replacing a dark roof with a white roof was 1:4 for the month of July, and 1:5 annually in Portland. The COP of the associated chillers ranges from 2.8-4.2, indicating that the ratio of cooling energy savings to heat flux reduction is not accounted for solely by the COP of the chillers. The results of the building simulation indicate that based on energy savings alone, white roofs are not an optimal choice for Portland. The benefits associated with cooling energy savings relative to a black roof are offset by the winter-time penalty, and the net benefit from adopting white roof technology in Portland is small. That said, there are other potential benefits of white roofing such as impact on urban heat islands and roof life that must also be considered.

Vuppuluri, Prem Kiran

74

Using Green Roofs to Minimize Roof Runoff Pollution  

E-print Network

10/31/2008 1 Using Green Roofs to Minimize Roof Runoff Pollution Brett LongBrett Long Shirley Clark:Relating to traditional stormwater design methods: ­­ Rational coefficients of green roofs:Rational coefficients of green roofs: Green roofs have a rational coefficient of about 0.5Green roofs have a rational coefficient

Clark, Shirley E.

75

LIGHTWEIGHT GREEN ROOF SYSTEMS  

EPA Science Inventory

Applying a Lightweight Green Roof System to a building can achieve in managing storm water runoff, decreasing heat gain, yielding energy savings, and mitigating the heat island effect. Currently, Most green roof systems are considerably heavy and require structural reinforceme...

76

Thermal interface pastes nanostructured for high performance  

Microsoft Academic Search

Thermal interface materials in the form of pastes are needed to improve thermal contacts, such as that between a microprocessor and a heat sink of a computer. High-performance and low-cost thermal pastes have been developed in this dissertation by using polyol esters as the vehicle and various nanoscale solid components. The proportion of a solid component needs to be optimized,

Chuangang Lin

2009-01-01

77

Performance analysis of solar thermal power systems  

Microsoft Academic Search

Methods of analyzing and predicting the performance of solar thermal power plants for electric applications are discussed, and insight provided into the major energy loss mechanisms for solar thermal systems. The efficiency of each component in a solar thermal plant is discussed as are the plant parasitic losses and plant availability. This is followed by a discussion of the computer

T. A. Williams; J. A. Dirks

1987-01-01

78

Which Roof Is Tops?  

NSDL National Science Digital Library

When you walk or drive around your neighborhood, what do the roofs look like? What if you lived in an area with a different climate, how might that affect the style of roofs that you see? Through this introductory engineering activity, students explore the advantages of different roof shapes for different climates or situations. They observe and discuss what happens in a teacher demo when a "snow load" (sifted cups of flour) is placed on three model roof shapes.

Center for Engineering Educational Outreach,

79

Solar energy absorbing roof  

Microsoft Academic Search

A roof structure has a supporting base on which a layer of insulating material is placed and over which is a metal layer having water circulating channels. The metal layer is covered by a water proofing layer, the outer surface of which is covered with mineral particles. The roof structure serves both the function of a conventional roof and a

Ronc

1980-01-01

80

Summer Roof Maintenance.  

ERIC Educational Resources Information Center

Presents the items to review in roofing maintenance to prepare for the impact of summer, including checking drainage, roof-field surface and membrane, flashings, sheet metal, and rooftop equipment, such as skylights and penthouses. A list of roofing facts facility managers should know are highlighted. (GR)

Liscum, Curtis L.

1999-01-01

81

Green roof systems: a study of public attitudes and preferences in southern Spain.  

PubMed

This study investigates people's preconceptions of green roofs and their visual preference for different green roof design alternatives in relation to behavioral, social and demographical variables. The investigation was performed as a visual preference study using digital images created to represent eight different alternatives: gravel roof, extensive green roof with Sedums not in flower, extensive green roof with sedums in bloom, semi-intensive green roof with sedums and ornamental grasses, semi-intensive green roof with shrubs, intensive green roof planted with a lawn, intensive green roof with succulent and trees and intensive green roof with shrubs and trees. Using a Likert-type scale, 450 respondents were asked to indicate their preference for each digital image. Results indicated that respondents' sociodemographic characteristics and childhood environmental background influenced their preferences toward different green roof types. Results also showed that green roofs with a more careful design, greater variety of vegetation structure, and more variety of colors were preferred over alternatives. PMID:23722180

Fernandez-Cañero, Rafael; Emilsson, Tobias; Fernandez-Barba, Carolina; Herrera Machuca, Miguel Ángel

2013-10-15

82

Thermal Performance Challenges from Silicon to Systems  

Microsoft Academic Search

The demand for high-performance microprocessors has resulted in an escalation of power dissipation as well as heat flux at the silicon level. At the same time, the desire for smaller form-factor chassis and lower silicon operating temperatures is compounding the thermal challenge. Thermal design for a microprocessor can no longer be treated in isolation. Power and performance trade offs and

Ram Viswanath; Vijay Wakharkar; Vassou Lebonheur

2000-01-01

83

Evolution of cool-roof standards in the United States  

SciTech Connect

Roofs that have high solar reflectance and high thermal emittance stay cool in the sun. A roof with lower thermal emittance but exceptionally high solar reflectance can also stay cool in the sun. Substituting a cool roof for a noncool roof decreases cooling-electricity use, cooling-power demand, and cooling-equipment capacity requirements, while slightly increasing heating-energy consumption. Cool roofs can also lower citywide ambient air temperature in summer, slowing ozone formation and increasing human comfort. Provisions for cool roofs in energy-efficiency standards can promote the building- and climate-appropriate use of cool roofing technologies. Cool-roof requirements are designed to reduce building energy use, while energy-neutral cool-roof credits permit the use of less energy-efficient components (e.g., larger windows) in a building that has energy-saving cool roofs. Both types of measures can reduce the life-cycle cost of a building (initial cost plus lifetime energy cost). Since 1999, several widely used building energy-efficiency standards, including ASHRAE 90.1, ASHRAE 90.2, the International Energy Conservation Code, and California's Title 24 have adopted cool-roof credits or requirements. This paper reviews the technical development of cool-roof provisions in the ASHRAE 90.1, ASHRAE 90.2, and California Title 24 standards, and discusses the treatment of cool roofs in other standards and energy-efficiency programs. The techniques used to develop the ASHRAE and Title 24 cool-roof provisions can be used as models to address cool roofs in building energy-efficiency standards worldwide.

Akbari, Hashem; Akbari, Hashem; Levinson, Ronnen

2008-07-11

84

Photovoltaic/thermal system performance index based on the second law  

NASA Astrophysics Data System (ADS)

The second law of thermodynamics is used to optimize the performance of residential hybrid photovoltaic/thermal energy system and the associated control system methodology. The system functioned with photovoltaics embedded in flat plate collectors for roof mounting. The thermal energy was captured by a heat pump. The PV/T system component irreversibilities were calculated and a minimum system performance index model was defined, based on the irreversibilities. The model was applied, with meteorological data, to simulate the system performance at three widely space U.S. locations. The control strategy was heavily latitude dependent. Finally, the second law model identified the irreversibilities of the collector and the room enclosures as the areas where improvements would yield the highest efficiency gains.

Bazques, E. O.; Anand, D. K.

1984-12-01

85

Thermal performance of three solar air heaters  

Microsoft Academic Search

This paper reports the thermal analysis and the results of thermal performance tests of solar air heaters with V-corrugated absorber plates. Six collector units were used to test three collector types: (a) flow over the absorber, (b) flow on both sides of the absorber, and (c) flow under the absorber. Paired simultaneous testing was used for collectors of the same

B. F. Parker; M. R. Lindley; D. G. Colliver; W. E. Murphy

1993-01-01

86

Theoretical analysis to investigate thermal performance of co-axial heat pipe solar collector  

NASA Astrophysics Data System (ADS)

The thermal performance of co-axial heat pipe solar collector which consist of a collector 15 co-axial heat pipes surrounded by a transparent envelope and which heat a fluid flowing through the condenser tubes have been predicted using heat transfer analytical methods. The analysis considers conductive and convective losses and energy transferred to a fluid flowing through the collector condenser tubes. The thermal performances of co-axial heat pipe solar collector is developed and are used to determine the collector efficiency, which is defined as the ratio of heat taken from the water flowing in the condenser tube and the solar radiation striking the collector absorber. The theoretical water outlet temperature and efficiency are compared with experimental results and it shows good agreement between them. The main advantage of this collector is that inclination of collector does not have influence on performance of co-axial heat pipe solar collector therefore it can be positioned at any angle from horizontal to vertical. In high building where the roof area is not enough the co-axial heat pipe solar collectors can be installed on the roof as well as wall of the building. The other advantage is each heat pipe can be topologically disconnected from the manifold.

Azad, E.

2011-12-01

87

Natural selection on thermal performance in a novel thermal environment.  

PubMed

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming. PMID:25225361

Logan, Michael L; Cox, Robert M; Calsbeek, Ryan

2014-09-30

88

Natural selection on thermal performance in a novel thermal environment  

PubMed Central

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming. PMID:25225361

Logan, Michael L.; Cox, Robert M.; Calsbeek, Ryan

2014-01-01

89

Urban solarium : thermal performance in Boston  

E-print Network

This thesis addresses the issue of energy efficiency through the lens of thermal performance in the context of urban housing in the city of Boston. Located in the historic brick row house neighborhood of the South End, the ...

Hsu, Juliet Chia-Wen

2012-01-01

90

Mine roof support structure  

SciTech Connect

A mine roof support structure includes a floor skid, a supporting shield pivotally connected thereto by a pair of rocker arms forming a lemniscate guide, a roof cap pivotally connected at a roof cap joint to the shield, and hydraulic props supporting the roof cap. A hydraulic actuator is pivotally connected at opposite ends to the skid and to one of the arms, and the other of the rocker arms is disposed nearer the coal-face end of the support than the one arm. Such other arm is longitudinally adjustable and is pivotally connected at opposite ends to the skid and to the shield. This other arm is so constructed that its opposite ends may be adjusted relative to one another to enable the cap and the roof cap joint to follow a lemniscate path during settling of the roof and to follow a circular arc during a lowering of the cap toward the skid upon actuation of the hydraulic actuator.

Boer, W.; Lachner, H.; Maschonat, G.; Richter, J.; Schulte, H.; Warnke, H.

1981-10-06

91

Thermal performance testing of industrial heat exchangers  

Microsoft Academic Search

Methods to perform thermal performance tests and analyze the results for heat exchangers in industrial process streams are discussed. Industrial test practices and operating conditions are compared with experimental methods. A thorough review of sources of error and their contribution to overall test uncertainty is described. The analysis includes methods to estimate the uncertainty of predicted performance based on test

Kenneth Bell

2001-01-01

92

Performance of a building integrated photovoltaic\\/thermal (BIPVT) solar collector  

Microsoft Academic Search

The idea of combining photovoltaic and solar thermal collectors (PVT collectors) to provide electrical and heat energy is an area that has, until recently, received only limited attention. Although PVTs are not as prevalent as solar thermal systems, the integration of photovoltaic and solar thermal collectors into the walls or roofing structure of a building could provide greater opportunity for

T. N. Anderson; M. Duke; G. L. Morrison; J. K. Carson

2009-01-01

93

Why Cool Roofs?  

ScienceCinema

By installing a cool roof at DOE, the federal government and Secretary Chu are helping to educate families and businesses about the important energy and cost savings that can come with this simple, low-cost technology. Cool roofs have the potential to quickly and dramatically reduce global carbon emissions while saving money every month on consumers' electrical bills.

Chu, Steven

2013-05-29

94

Why Cool Roofs?  

SciTech Connect

By installing a cool roof at DOE, the federal government and Secretary Chu are helping to educate families and businesses about the important energy and cost savings that can come with this simple, low-cost technology. Cool roofs have the potential to quickly and dramatically reduce global carbon emissions while saving money every month on consumers' electrical bills.

Chu, Steven

2010-01-01

95

Modeling of solar pond thermal performance  

SciTech Connect

The utility of solar ponds depends on the amount of thermal energy that the pond can deliver and the cost of constructing and maintaining the pond. Proper engineering of a solar pond requires that the size of the pond be carefully chosen to match the intended load. The thermal performance of a solar pond depends on how much incident solar radiation is collected, how much heat is lost through the gradient zone, how much heat is lost to the ground, the total storage capacity, and the effectiveness of the heat extraction system. The thermal behavior is relatively well understood because it depends basically on heat conduction, and it is much more advanced than the understanding of solar pond hydrodynamic behavior. Several of the different design methods available to predict thermal performance are discussed in this paper.

Hull, J.R.

1987-01-01

96

Thermal performance of double-skin facade with thermal mass  

NASA Astrophysics Data System (ADS)

In order to mitigate the overheating problem in the warmer seasons, and thereby to improve thermal performance and energy efficiency of the Double-Skin Facade (DSF) system, this study introduced an innovative design approach involving the integration of thermal mass with the air channel of the conventional DSF. Then it proposed a numerical procedure to assess the thermal performance of DSF, and finally investigated the effect of thermal mass on the energy efficiency of such system. The initial step in the assessment procedure proposed the development of base-case models, which were able to predict temperature distribution in the DSF with a venetian blind. So too were the base-case models able to determine heating/cooling loads of the perimeter room for both the mechanically and naturally ventilated DSFs. In this procedure, building energy simulation software was used for base-case development; two distinct models were generated: an airflow model and a thermal model. The nodal, unidirectional airflow network method was applied in the case of the naturally ventilated DSF. The thermal model was a transient control volume method which found temperature distribution in discretized air-channel. The base-cases were verified at two levels: inter-model verification and verification relying on measurements from mechanically and naturally ventilated outdoor test-cells. At both levels, a generally fair agreement was obtained. After this, parametric studies pertaining to the energy performance of the system were conducted on the effect of thermal mass in unison with different air-channel configurations. Considerable energy load reductions were found when thermal mass was used in the air-channel, replacing venetian blind slats for mechanically ventilated DSFs; this held true during both summer and winter. In this configuration depending on the airflow path direction, energy savings from 21% to 26% in summer and from 41% to 59% in winter are achievable in compared with conventional DSF with aluminum venetian blind. The savings were found higher in sunny days than cloudy days. On the other hand, naturally ventilated DSFs combined with thermal mass were not found to be energy efficient in winter due to stack effect and airflow rate increase within the air channel.

Fallahi, Ali

97

Potential energy cost savings by use of building roofs as thermal storage of a multi-storied building  

NASA Astrophysics Data System (ADS)

The thermal mass of a building has been used for more than two decades to shift the peak cooling load occurring during the day time to evening or night time. This is typically accomplished by use of concrete slabs embedded with pipes carrying hot or chilled water to meet the heating or cooling load, respectively. The water temperature drops across the coils and the frequency and intensity of room air circulation can be varied, along with controlling the gains through the windows, to shift the peak load hours to the nighttime when energy costs are cheaper and electric demands are lower. This thesis deals with the transient finite element heat transfer analysis of a concrete slab embedded with pipes circulating heated or chilled water of a multi-storied office building. A hypothetical office building in Chattanooga, Tennessee, USA is analyzed with weather data of that locale. The electrical power consumption of such a system operating at milder conditions or evening or night hours is estimated by use of hourly weather data. The estimated electric power consumption is then compared to the traditional method of operations. The influence of the wall envelope, including the size and orientation of windows, is considered in reducing the energy gain or loss from the space. The results presented in this thesis identify the potential energy cost savings of such a system as well as challenges involved compared to traditional buildings in commercial applications.

Shelbaya, Ahmad Adam

98

Cool Roof Systems; What is the Condensation Risk?  

SciTech Connect

A white roof, or cool roof, is constructed to decrease thermal loads from solar radiation, therefore saving energy by decreasing the cooling demands. Unfortunately, cool roofs with a mechanically attached membrane have shown a higher risk of intermediate condensation in the materials below the membrane in certain climates (Ennis & Kehrer, 2011) and in comparison with similar constructions with a darker exterior surface (Bludau, Zirkelbach, & Kuenzel, 2009). As a consequence, questions have been raised regarding the sustainability and reliability of using cool roof membranes in northern U.S. climate zones.

Kehrer, Manfred [ORNL; Pallin, Simon B [ORNL

2014-01-01

99

Protected Membrane Roofs: A Sustainable Roofing Solution.  

ERIC Educational Resources Information Center

Examines the benefits of protected membrane roofing (PMR) for school buildings. PMR uses an upside-down approach, where the insulation is placed on top of the waterproofing membrane to improve membrane effectiveness, reduce ultraviolet degradation, and improve insulation efficiency. The article explains what makes PMR sustainable, focusing on…

Roodvoets, David L.

2003-01-01

100

Roofing Workbook and Tests: Rigid Roofing.  

ERIC Educational Resources Information Center

This document is one of a series of nine individual units of instruction for use in roofing apprenticeship classes in California. The unit consists of a workbook and test. Eight topics are covered in the workbook and corresponding multiple-choice tests. For each topic, objectives and information sheets are provided. Information sheets are…

Klingensmith, Robert, Ed.

101

Solar electric and thermal conversion system in close proximity to the consumer. [solar panels on house roofs  

NASA Technical Reports Server (NTRS)

Solar cells may be used to convert sunlight directly into electrical energy and into lowgrade heat to be used for large-scale terrestrial solar-energy conversion. Both forms of energy can be utilized if such cells are deployed in close proximity to the consumer (rooftop). Cadmium-sulfide/copper-sulfide (CdS/Cu2S) solar cells are an example of cells which may be produced inexpensively enough to become economically attractive. Cell parameters relevant for combined solar conversion are presented. Critical issues, such as production yield, life expectancy, and stability of performance, are discussed. Systems-design parameters related to operating temperatures are analyzed. First results obtained on Solar One, the experimental house of the University of Delaware, are given. Economic aspects are discussed. Different modes of operation are discussed in respect to the power utility and consumer incentives.

Boeer, K. W.

1975-01-01

102

Thermal Performance Testing of Cryogenic Insulation Systems  

NASA Technical Reports Server (NTRS)

Efficient methods for characterizing thermal performance of materials under cryogenic and vacuum conditions have been developed. These methods provide thermal conductivity data on materials under actual-use conditions and are complementary to established methods. The actual-use environment of full temperature difference in combination with vacuum-pressure is essential for understanding insulation system performance. Test articles include solids, foams, powders, layered blankets, composite panels, and other materials. Test methodology and apparatus design for several insulation test cryostats are discussed. The measurement principle is liquid nitrogen boil-off calorimetry. Heat flux capability ranges from approximately 0.5 to 500 watts per square meter; corresponding apparent thermal conductivity values range from below 0.01 up to about 60 mW/m- K. Example data for different insulation materials are also presented. Upon further standardization work, these patented insulation test cryostats can be available to industry for a wide range of practical applications.

Fesmire, James E.; Augustynowicz, Stan D.; Scholtens, Brekke E.

2007-01-01

103

GREEN ROOFS ? A GROWING TREND  

EPA Science Inventory

One of the most interesting stormwater control systems under evaluation by EPA are ?green roofs?. Green roofs are vegetative covers applied to building roofs to slow, or totally absorb, rainfall runoff during storms. While the concept of over-planted roofs is very ancient, the go...

104

Accelerated Development and Sustainability: The Retrofit of Green Roofs in City Centres  

Microsoft Academic Search

Although it has a relatively low profile, one method of increasing sustainability in buildings currently being considered is the provision of green roofs. Most importantly, green roofs have thermal benefits in reducing heat loss and reducing heat gain and also enhancing bio- diversity. Furthermore, green roofs can absorb some of the carbon emissions in the CBD. With the increasing emphasis

Sara J. WILKINSON; Richard REED

105

Mine roof support plate  

SciTech Connect

A support plate is disclosed for a mine roof including a substantially flat body engageable with the mine roof, the body having an enlarged central opening through which are passed one end of a roof bolt on which is threaded an expansion shell which is inserted into a mine roof opening. Ribs extend longitudinally of the flat body on both sides of the central opening for additional strength. The ribs are spaced a predetermined distance apart on opposite sides of the central opening. Centering members are provided on the body portion intermediate the ribs on opposite sides of the central opening, the centering members and ribs serving to center the washer and bolt portion of the bolt assembly.

White, C.C.

1981-02-10

106

Solar power roof shingle  

NASA Technical Reports Server (NTRS)

Silicon solar cell module provides both all-weather protection and electrical power. Module consists of array of circular silicon solar cells bonded to fiberglass substrate roof shingle with fluorinated ethylene propylene encapsulant.

Forestieri, A. F.; Ratajczak, A. F.; Sidorak, L. G.

1975-01-01

107

Roof Coatings Manufacturers Association  

NSDL National Science Digital Library

Created by the Roof Coatings Manufacturers Association, a trade association which represents manufacturers of cold-applied coatings and cements used in the roofing industry, this site provides users with a useful assortment of materials as well as some basic information about the association itself. The easy to navigate site offers users an overview that details some specifics on cold applied roof coatings including a brief history, the types of coatings available and the product's advantages. A list of organizational links, articles and technical bulletins provide more in depth information on topics related to application of roof coatings, weather related concerns, fire ratings, white coatings and much more. A news and events page and a supplier�s directory are valuable additions to this useful site.

108

Science Nation: Green Roofs  

NSDL National Science Digital Library

The rooftops of Manhattan are as varied as the city itself. But on some, something new is taking root--literally! A green roof is a continuous layer of living plants. Looking down several stories from the windows of neighboring buildings, the rooftop resembles a well-manicured, suburban lawn that is simply contained within the boundaries of a flat Manhattan rooftop. Researchers are investigating what benefits green roofs might have on harsh urban environments.

109

Waterproof that Roof!  

NSDL National Science Digital Library

In this activity, learners explore how engineers have improved roofing designs and materials in order to protect the contents of buildings. Learners explore the hydrophobic effect, and learn about nanotechnology. Then, they work in teams to design a roof structure both in terms of shape and materials to protect a box and its contents from a simulated rainstorm. Teams build, test, and evaluate their designs and those of other teams.

IEEE

2014-05-23

110

Thermal interface pastes nanostructured for high performance  

NASA Astrophysics Data System (ADS)

Thermal interface materials in the form of pastes are needed to improve thermal contacts, such as that between a microprocessor and a heat sink of a computer. High-performance and low-cost thermal pastes have been developed in this dissertation by using polyol esters as the vehicle and various nanoscale solid components. The proportion of a solid component needs to be optimized, as an excessive amount degrades the performance, due to the increase in the bond line thickness. The optimum solid volume fraction tends to be lower when the mating surfaces are smoother, and higher when the thermal conductivity is higher. Both a low bond line thickness and a high thermal conductivity help the performance. When the surfaces are smooth, a low bond line thickness can be even more important than a high thermal conductivity, as shown by the outstanding performance of the nanoclay paste of low thermal conductivity in the smooth case (0.009 mum), with the bond line thickness less than 1 mum, as enabled by low storage modulus G', low loss modulus G" and high tan delta. However, for rough surfaces, the thermal conductivity is important. The rheology affects the bond line thickness, but it does not correlate well with the performance. This study found that the structure of carbon black is an important parameter that governs the effectiveness of a carbon black for use in a thermal paste. By using a carbon black with a lower structure (i.e., a lower DBP value), a thermal paste that is more effective than the previously reported carbon black paste was obtained. Graphite nanoplatelet (GNP) was found to be comparable in effectiveness to carbon black (CB) pastes for rough surfaces, but it is less effective for smooth surfaces. At the same filler volume fraction, GNP gives higher thermal conductivity than carbon black paste. At the same pressure, GNP gives higher bond line thickness than CB (Tokai or Cabot). The effectiveness of GNP is limited, due to the high bond line thickness. A thermal paste that is particularly effective for smooth surfaces was obtained by using nanoclay platelets (obtained by organic modification and subsequent chemical exfoliation) as the solid component. The superiority of the nanoclay paste for smooth surfaces is attributed to the submicrometer bond line thickness. Electrically nonconductive high-performance thermal paste was obtained by using either fumed alumina or fumed zinc oxide. The nonconductivity serves to avoid short circuiting in the electronic application environment. The fumed oxides are as effective as carbon black, but are advantageous in their electrical nonconductivity. Without fuming, the oxides are less effective. The silane coating on fumed metal oxides helps. Electrically nonconductive thermal pastes have also been attained using carbon as the thermally conductive solid component. Either fumed alumina or nanoclay is used to break the electrical connectivity of the carbon in the paste to obtain electrical nonconductivity. Among the nanostrucutred pastes developed in this dissertation research, the nanoclay (0.6 vol.%) paste is recommended for smooth surfaces. With the overall performance for smooth and rough surfaces considered, the carbon black (Tokai, 15 vol.%) paste is recommended. Carbon black (Tokai) is more effective than carbon black (Cabot), due to its small aggregate size. All the pastes developed are much more effective than carbon nanotube arrays investigated by others. The rheological behavior of the thermal pastes was studied under strain sweep, frequency sweep, steady state flow and temperature ramping. In the absence of a solid component, the vehicle is Newtonian and fluid-like. In the presence of a solid component, the paste is a Bingham plastic that exhibits shear thinning and mainly solid-like behavior. The addition of antioxidants enhances the solid-like character, increases the yield stress, the plastic viscosity and the bond line thickness, and decreases the thermal contact conductance. Double yielding behavior was observed in the CB(Cabot) and CB(Tokai) pastes, but not in t

Lin, Chuangang

111

The effects of high temperature and roof modification on physiological responses of swamp buffalo ( Bubalus bubalis) in the tropics  

NASA Astrophysics Data System (ADS)

The objective of the experiments reported here was to measure the effects of cooling techniques (Modified roof vs Normal roof) on the performance and physiology of 12 young male buffaloes with a similar live weight of 160 kg. The study was conducted at Chainat Agriculture and Technology College, Chainat Province, Thailand. The animals were divided randomly into two groups, each group comprising six buffaloes, and the two groups were studied to evaluate the effects of modified roofing (normal roof fitted with woven polypropylene shade cloth) on the subjects' physiological responses to heat stress under hot humid conditions. The modified roof resulted in lowered heat stress in buffaloes compared to those under a standard roof. The difference was shown by the buffaloes having a significantly lower mean rectal temperature (39.14 ± 0.07 vs 40.00 ± 0.10°C) and plasma cortisol (2.14 ± 0.24 vs 3.38 ± 0.37 ng/ml). The average daily water consumption was significantly lower in the MR group (MR, 29.71 ± 0.86 vs NR, 34.14 ± 1.06 L head -1 day-1), while there was a tendency for the roughage intake to be higher in the MR group compared to that of the NR group (MR, 5.88 ± 0.18 vs NR, 6.44 ± 0.19 kg head-1 -1 day-1; P = 0.0508). It was concluded that roof modification facilitated a reduction in heat load from roof re-radiation, and was an effective means of alleviating thermal stress in young buffaloes.

Khongdee, Titaporn; Sripoon, S.; Vajrabukka, C.

2013-05-01

112

Fourier analysis of conductive heat transfer for glazed roofing materials  

SciTech Connect

For low-rise buildings, roof is the most exposed surface to solar radiation. The main mode of heat transfer from outdoor via the roof is conduction. The rate of heat transfer and the thermal impact is dependent on the thermophysical properties of roofing materials. Thus, it is important to analyze the heat distribution for the various types of roofing materials. The objectives of this paper are to obtain the Fourier series for the conductive heat transfer for two types of glazed roofing materials, namely polycarbonate and polyfilled, and also to determine the relationship between the ambient temperature and the conductive heat transfer for these materials. Ambient and surface temperature data were collected from an empirical field investigation in the campus of Universiti Teknologi MARA Shah Alam. The roofing materials were installed on free-standing structures in natural ventilation. Since the temperature data are generally periodic, Fourier series and numerical harmonic analysis are applied. Based on the 24-point harmonic analysis, the eleventh order harmonics is found to generate an adequate Fourier series expansion for both glazed roofing materials. In addition, there exists a linear relationship between the ambient temperature and the conductive heat transfer for both glazed roofing materials. Based on the gradient of the graphs, lower heat transfer is indicated through polyfilled. Thus polyfilled would have a lower thermal impact compared to polycarbonate.

Roslan, Nurhana Lyana; Bahaman, Nurfaradila; Almanan, Raja Noorliyana Raja; Ismail, Razidah [Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Zakaria, Nor Zaini [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

2014-07-10

113

Fourier analysis of conductive heat transfer for glazed roofing materials  

NASA Astrophysics Data System (ADS)

For low-rise buildings, roof is the most exposed surface to solar radiation. The main mode of heat transfer from outdoor via the roof is conduction. The rate of heat transfer and the thermal impact is dependent on the thermophysical properties of roofing materials. Thus, it is important to analyze the heat distribution for the various types of roofing materials. The objectives of this paper are to obtain the Fourier series for the conductive heat transfer for two types of glazed roofing materials, namely polycarbonate and polyfilled, and also to determine the relationship between the ambient temperature and the conductive heat transfer for these materials. Ambient and surface temperature data were collected from an empirical field investigation in the campus of Universiti Teknologi MARA Shah Alam. The roofing materials were installed on free-standing structures in natural ventilation. Since the temperature data are generally periodic, Fourier series and numerical harmonic analysis are applied. Based on the 24-point harmonic analysis, the eleventh order harmonics is found to generate an adequate Fourier series expansion for both glazed roofing materials. In addition, there exists a linear relationship between the ambient temperature and the conductive heat transfer for both glazed roofing materials. Based on the gradient of the graphs, lower heat transfer is indicated through polyfilled. Thus polyfilled would have a lower thermal impact compared to polycarbonate.

Roslan, Nurhana Lyana; Bahaman, Nurfaradila; Almanan, Raja Noorliyana Raja; Ismail, Razidah; Zakaria, Nor Zaini

2014-07-01

114

30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.  

Code of Federal Regulations, 2013 CFR

...Installation of roof support using mining machines with integral roof bolters. 75.205...Installation of roof support using mining machines with integral roof bolters. When...bolts are installed by a continuous mining machine with intregal roof bolting...

2013-07-01

115

30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.  

Code of Federal Regulations, 2014 CFR

...Installation of roof support using mining machines with integral roof bolters. 75.205...Installation of roof support using mining machines with integral roof bolters. When...bolts are installed by a continuous mining machine with intregal roof bolting...

2014-07-01

116

30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.  

Code of Federal Regulations, 2010 CFR

...Installation of roof support using mining machines with integral roof bolters. 75.205...Installation of roof support using mining machines with integral roof bolters. When...bolts are installed by a continuous mining machine with intregal roof bolting...

2010-07-01

117

30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.  

Code of Federal Regulations, 2011 CFR

...Installation of roof support using mining machines with integral roof bolters. 75.205...Installation of roof support using mining machines with integral roof bolters. When...bolts are installed by a continuous mining machine with intregal roof bolting...

2011-07-01

118

30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.  

Code of Federal Regulations, 2012 CFR

...Installation of roof support using mining machines with integral roof bolters. 75.205...Installation of roof support using mining machines with integral roof bolters. When...bolts are installed by a continuous mining machine with intregal roof bolting...

2012-07-01

119

ROOF, A view looking north from the stair tower roof ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ROOF, A view looking north from the stair tower roof at the external piping - Department of Energy, Mound Facility, Hydrolysis House Building (HH Building), One Mound Road, Miamisburg, Montgomery County, OH

120

5. MAIN BAY SHOWING ROOF CONSTRUCTION, ROOF TRUSS, CLERESTORY MONITOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. MAIN BAY SHOWING ROOF CONSTRUCTION, ROOF TRUSS, CLERESTORY MONITOR, AND GIRDER FOR ELECTRIC OVERHEAD TRAVEL CRANE (BOTTOM) - Oldman Boiler Works, Boilershop, 32 Illinois Street, Buffalo, Erie County, NY

121

Thermal Performance of Aircraft Polyurethane Seat Cushions  

NASA Technical Reports Server (NTRS)

Aircraft seat materials were evaluated in terms of their thermal performance. The materials were evaluated using (a) thermogravimetric analysis, (b) differential scanning calorimetry, (c) a modified NBS smoke chamber to determine the rate of mass loss and (d) the NASA T-3 apparatus to determine the thermal efficiency. In this paper, the modified NBS smoke chamber will be described in detail since it provided the most conclusive results. The NBS smoke chamber was modified to measure the weight loss of material when exposed to a radiant heat source over the range of 2.5 to 7.5 W/sq cm. This chamber has been utilized to evaluate the thermal performance of various heat blocking layers utilized to protect the polyurethane cushioning foam used in aircraft seats. Various kinds of heat blocking layers were evaluated by monitoring the weight loss of miniature seat cushions when exposed to the radiant heat. The effectiveness of aluminized heat blocking systems was demonstrated when compared to conventional heat blocking layers such as neoprene. All heat blocking systems showed good fire protection capabilities when compared to the state-of-the-art, i.e., wool-nylon over polyurethane foam.

Kourtides, D. A.; Parker, J. A.

1982-01-01

122

Shuttle TPS thermal performance and analysis methodology  

NASA Technical Reports Server (NTRS)

Thermal performance of the thermal protection system was approximately as predicted. The only extensive anomalies were filler bar scorching and over-predictions in the high Delta p gap heating regions of the orbiter. A technique to predict filler bar scorching has been developed that can aid in defining a solution. Improvement in high Delta p gap heating methodology is still under study. Minor anomalies were also examined for improvements in modeling techniques and prediction capabilities. These include improved definition of low Delta p gap heating, an analytical model for inner mode line convection heat transfer, better modeling of structure, and inclusion of sneak heating. The limited number of problems related to penetration items that presented themselves during orbital flight tests were resolved expeditiously, and designs were changed and proved successful within the time frame of that program.

Neuenschwander, W. E.; Mcbride, D. U.; Armour, G. A.

1983-01-01

123

Green Roofs for Stormwater Runoff Control - Abstract  

EPA Science Inventory

This project evaluated green roofs as a stormwater management tool. Specifically, runoff quantity and quality from green and flat asphalt roofs were compared. Evapotranspiration from planted green roofs and evaporation from unplanted media roofs were also compared. The influence...

124

Green Roofs for Stormwater Runoff Control  

EPA Science Inventory

¿This project evaluated green roofs as a stormwater management tool. Specifically, runoff quantity and quality from green and flat asphalt roofs were compared. Evapotranspiration from planted green roofs and evaporation from unplanted media roofs were also compared. The influence...

125

24. Roof detail from liftbed truck, showing pan roof above ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. Roof detail from lift-bed truck, showing pan roof above breezeway, with sawn redwood trim, tube-type drains; note missing rain gutter at roof edge, deteriorated condition of slates; view to south, 90mm lens. - Southern Pacific Depot, 559 El Camino Real, San Carlos, San Mateo County, CA

126

THERMAL PERFORMANCE ANALYSIS FOR WSB DRUM  

SciTech Connect

The Nuclear Nonproliferation Programs Design Authority is in the design stage of the Waste Solidification Building (WSB) for the treatment and solidification of the radioactive liquid waste streams generated by the Pit Disassembly and Conversion Facility (PDCF) and Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). The waste streams will be mixed with a cementitious dry mix in a 55-gallon waste container. Savannah River National Laboratory (SRNL) has been performing the testing and evaluations to support technical decisions for the WSB. Engineering Modeling & Simulation Group was requested to evaluate the thermal performance of the 55-gallon drum containing hydration heat source associated with the current baseline cement waste form. A transient axi-symmetric heat transfer model for the drum partially filled with waste form cement has been developed and heat transfer calculations performed for the baseline design configurations. For this case, 65 percent of the drum volume was assumed to be filled with the waste form, which has transient hydration heat source, as one of the baseline conditions. A series of modeling calculations has been performed using a computational heat transfer approach. The baseline modeling results show that the time to reach the maximum temperature of the 65 percent filled drum is about 32 hours when a 43 C initial cement temperature is assumed to be cooled by natural convection with 27 C external air. In addition, the results computed by the present model were compared with analytical solutions. The modeling results will be benchmarked against the prototypic test results. The verified model will be used for the evaluation of the thermal performance for the WSB drum.

Lee, S

2008-06-26

127

High-Tech Roof Management.  

ERIC Educational Resources Information Center

Describes the use of a computerized roof management system (CRMS) for school districts to foster multiple roof maintenance efficiency and cost effectiveness. Highlights CRMS software manufacturer choices, as well as the types of nondestructive testing equipment tools that can be used to evaluate roof conditions. (GR)

Benzie, Tim

1997-01-01

128

Performance Modeling of an Air-Based Photovoltaic/Thermal (PV/T) Collector  

SciTech Connect

This paper studies a collector design that utilizes unglazed photovoltaic/thermal (PV/T) collectors preheating air for glazed air heating modules. The performance modeling of these collectors is examined both individually and in series. For each collector type, a dynamic, finite difference, first-law model has been created using literature correlations for friction. The models were compared to performance data, calibrating the models by scaling of friction terms for best fit. The calibrated models generally agree well with the experimental data; even during sudden changes to ambient conditions. The root mean square error between the unglazed PV/T model and experiment results for the useful thermal energy gain and the outlet air temperature are 7.12 W/m{sup 2} and 1.07 C, respectively. The annual source energy performance of the building-integrated PV/T (BIPV/T) array is then simulated for residential applications in seven climate zones of the United States of America. The performance of the BIPV/T array is characterized by the amount of net electrical energy and useful thermal energy produced. The useful thermal energy is defined as the amount of energy offset by the BIPV/T system for water heating and space conditioning. A BIPV/T system composed 87.5% of PV modules, and 12.5% of glazed air heating modules, offsets the same amount of source energy as a roof-mounted PV system of the same area. This array composition increases the thermal energy gain by 47% over a BIPV/T array composed solely of PV modules.

Casey, R. D.; Brandemuehl, M. J.; Merrigan, T.; Burch, J.

2010-01-01

129

3.2: New Directions in Green Roof Research GREEN ROOF RESEARCH IN BRITISH COLUMBIA AN OVERVIEW  

Microsoft Academic Search

In 2002 a stakeholder workshop held in Vancouver identified the major barriers to the market penetration of green roofs in BC as the lack of climate-specific performance data, the absence of third party testing and verification of green roof systems, and a lack of demonstrated feasibility. To address these issues the British Columbia Institute of Technology (BCIT), supported by a

Maureen Connelly; Karen Liu

130

ACCESS: Thermal Mechanical Design, Performance, and Status  

NASA Astrophysics Data System (ADS)

Systematic errors associated with astrophysical data used to probe fundamental astrophysical questions, such as SNeIa observations used to constrain dark energy theories, are now rivaling and exceeding the statistical errors associated with these measurements. ACCESS: Absolute Color Calibration Experiment for Standard Stars is a series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 - 1.7?m bandpass. Achieving this level of accuracy requires characterization and stability of the instrument and detector including a thermal background that contributes less than 1% to the flux per resolution element in the NIR. We will present the instrument and calibration status with a focus on the thermal mechanical design and associated performance data. The detector control and performance will be presented in a companion poster (Morris, et al). NASA APRA sounding rocket grant NNX08AI65G supports this work.

Kaiser, Mary Elizabeth; Morris, M. J.; McCandliss, S. R.; Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.; Wright, E. L.; Bohlin, R.; Kurucz, R. L.; Riess, A. G.; Pelton, R.; Deustua, S. E.; Dixon, W. V.; Sahnow, D. J.; Benford, D. J.; Gardner, J. P.; Feldman, P. D.; Moos, H. W.; Lampton, M.; Perlmutter, S.; Woodgate, B. E.

2014-01-01

131

Numerical Simulations of a Roof-Top Wind Turbine  

NASA Astrophysics Data System (ADS)

Unsteady numerical simulations of a high efficiency roof-top wind turbine have been performed. The wind turbine cross section design was based on geometrical optimization study of Rahai and Hefazi for increasing contributions of the lift force to the torque, resulting in significant improvements in the performance of a vertical axis wind turbine. The wind turbine was 30 cm in diameter and 75 cm length, with 45 cm diameter end-plates, placed in the spanwise direction above a 26 degree slanted roof at 20 percent from the roof's highest elevation and one turbine diameter away from the roof surface. The approaching wind velocity was 30 m/sec and the wind turbine RPM was 233. Results indicate nearly 20 percent improvements in the power output, when compared with the corresponding results for a free standing wind turbine. However, the wind turbine operation imposes oscillatory stress on the roof, which could results in structural vibration and damage and noise generation.

Moayedian, Shahab; Rahai, Hamid

2010-11-01

132

High Performance Thermal Interface Technology Overview  

E-print Network

An overview on recent developments in thermal interfaces is given with a focus on a novel thermal interface technology that allows the formation of 2-3 times thinner bondlines with strongly improved thermal properties at lower assembly pressures. This is achieved using nested hierarchical surface channels to control the particle stacking with highly particle-filled materials. Reliability testing with thermal cycling has also demonstrated a decrease in thermal resistance after extended times with longer overall lifetime compared to a flat interface.

R. Linderman; T. Brunschwiler; B. Smith; B. Michel

2008-01-07

133

Performance of thermally applied organic coatings in a marine atmosphere  

SciTech Connect

Performance in a marine environment of thermally applied coatings was evaluated and compared to traditional solvent-borne systems. Thermally applied organic coated specimens were prepared using two of the three most popular thermal application methods. In addition to traditional accelerated laboratory test methods, coated test specimens were atmospherically exposed in a marine environment. Four programs involving the performance of thermally applied organic coatings were used as a database for performance comparisons. While thermally applied coatings offer unique attributes, no specific corrosion protection advantages of thermally applied coatings were identified.

Ault, J.P.; Farschon, C.L. [Ocean City Research Corp., NJ (United States)

1996-02-01

134

Energetic analysis of a passive solar design, incorporated in a courtyard after refurbishment, using an innovative cover component based in a sawtooth roof concept  

Microsoft Academic Search

This paper presents the experimental results and specific thermal and energetic saving analysis from the systematic monitoring carried out to analyse the energetic performance of a building with an innovative component, which is based on an optimisation of the sawtooth roof concept.This component has been installed at a building of the University of Almería. The constructive goal has been to

M. R. Heras; M. J. Jiménez; M. J. San Isidro; L. F. Zarzalejo; M. Pérez

2005-01-01

135

Thermal Performance of the SNS Cryomodule  

SciTech Connect

When complete, the Spallation Neutron Source (SNS) will provide a 1 GeV, 2 MW beam for experiments. One portion of the machine's linac consists of over 80 Superconducting Radio-Frequency (SRF) 805 MHz cavities housed in a total of 23 cryomodules (CMs) operating at 2.1 K. Minimization of the total heat load is critical to machine performance since the refrigerator capacity is fixed. The total heat load of the cryomodules consists of the fixed static load and the dynamic heat load, which is proportional to the cavity performance. The heat load of the cryomodules is the single largest load to the cooling circuits of the refrigerator. During acceptance testing at Jefferson Lab, a series of measurements have been taken on the prototype and first three production CMs. Calorimetric measurements of the primary heat load and shield heat load are presented and discussed. Temperature measurements taken allow a comparison between actual and predicted thermal performance of two components unique to this cryomodule design: the helium gas-cooled fundamental power coupler (FPC) and the helium heat exchanger (HX)

Daly, E.F.; Hogan, J.P.; Campisi, I.E.; Drury, M.; Machie, D.; Preble, J.; Rode, C.H.; Whitlatch, T.; Wilson, K.M.; Wiseman, M. [Thomas Jefferson National Accelerator Facility (Jefferson Lab), Newport News, VA, 23606 (United States)

2004-06-23

136

Cost and performance of thermal storage concepts in solar thermal systems, Phase 2-liquid metal receivers  

Microsoft Academic Search

Cost and performance of various thermal storage concepts in a liquid metal receiver solar thermal power system application have been evaluated. The objectives of this study are to provide consistently calculated cost and performance data for thermal storage concepts integrated into solar thermal systems. Five alternative storage concepts are evaluated for a 100-MW(e) liquid metal-cooled receiver solar thermal power system

A. W. McKenzie

1982-01-01

137

ALSEP Thermal Performance at Off-Equator Latitudes  

E-print Network

CONFIGURATION 33 THERMAL ANALYSIS 35 4. 1 SOLAR HEATING OF CENTRAL STATION ENCLOSURE AT LUNAR NOON 35 4.2 SOLARALSEP Thermal Performance at Off-Equator Latitudes NO. ATM-851 PAGE i REV. NO. OF v DATE 15 March recommended design changes and predicted thermal performance for the central station and associated

Rathbun, Julie A.

138

Energy Star{reg{underscore}sign} label for roof products  

SciTech Connect

Home and buildings owners can save up to 40% of cooling energy costs by installing reflective roofs, especially in hot and sunny climates. The increase in exterior albedo and subsequent decrease in heat flow across the building envelope reduces the energy requirements to maintain air-conditioned space. Indirectly, the increase in overall albedo of a community as these roofs are installed in a large fraction of the buildings results in lower ambient air temperature and less need for air conditioning. Another indirect effect is a decrease in smog formation due to lower ambient air temperatures and less air pollution from power plants because of minimized electrical demand and use. The US Environmental Protection Agency and the US Department of Energy are currently developing the Energy Star Roof Products Program to create a vibrant market for energy-efficient, cost-effective roof materials through the widespread availability of products, clear recognition of the benefits by consumers, and active promotion of products by manufacturers. Several activities, including pilot procurements of room materials, and the development of outreach and training materials, will be performed to assist the transformation of the roofing market toward more energy-efficient products. Using the experiences gained in establishing the Energy Star Roof Products Program as an example, this paper will discuss the barriers to the development of energy-efficient roofing practices, program implementation, and program successes. This paper will further describe the specifics of the Energy Star Roof Products Program, its goals, benefits, activities, and timeframe.

Schmeltz, R.S.; Bretz, S.E.

1998-07-01

139

Project Overcoat - An Exploration of Exterior Insulation Strategies for 1-1/2-Story Roof Applications in Cold Climates  

SciTech Connect

The development of an alternative method to interior-applied insulation strategies or exterior applied 'band-aids' such as heat tapes and ice belts may help reduce energy needs of millions of 1-1/2 story homes while reducing the risk of ice dam formation. A potential strategy for energy improvement of the roof is borrowed from new construction best practices: Here an 'overcoat' of a continuous air, moisture, and thermal barrier is applied on the outside of the roof structure for improved overall performance. The continuous insulation of this approach facilitates a reduction in thermal bridging which could further reduce energy consumption and bring existing homes closer to meeting the Building America goals for energy reduction. Research favors an exterior approach to deep energy retrofits and ice dam prevention in existing homes. The greatest amount of research focuses on whole house deep energy retrofits leaving a void in roof-only applications. The research is also void of data supporting the hygrothermal performance, durability, constructability, and cost of roof-only exterior overcoat strategies. Yet, contractors interviewed for this report indicate an understanding that exterior approaches are most promising for mitigating ice dams and energy loss and are able to sell these strategies to homeowners.

Ojczyk, C.; Mosiman, G.; Huelman, P.; Schirber, T.; Yost, P.; Murry, T.

2013-04-01

140

WMAP Observatory Thermal Design and On-Orbit Thermal Performance  

NASA Technical Reports Server (NTRS)

The Wilkinson Microwave Anisotropy Probe (WMAP) observatory, launched June 30, 2001, is designed to measure the cosmic microwave background radiation with unprecedented precision and accuracy while orbiting the second Lagrange point (L2). The instrument cold stage must be cooled passively to <95K, and systematic thermal variations in selected instrument components controlled to less than 0.5 mK (rms) per spin period. This paper describes the thermal design and testing of the WMAP spacecraft and instrument. Flight thermal data for key spacecraft and instrument components are presented from launch through the first year of mission operations. Effects of solar flux variation due to the Earth's elliptical orbit about the sun, surface thermo-optical property degradations, and solar flares on instrument thermal stability are discussed.

Glazer, Stuart D.; Brown, Kimberly D.; Michalek, Theodore J.; Ancarrow, Walter C.

2003-01-01

141

TASK 2.5.7 FIELD EXPERIMENTS TO EVALUATE COOL-COLORED ROOFING  

SciTech Connect

Aesthetically pleasing dark roofs can be formulated to reflect like a highly reflective white roof in the near infrared portion of the solar spectrum. New paint pigments increase the near infrared reflectance of exterior finishes by minimizing the absorption of near-infrared radiation (NIR). The boost in the NIR reflectance drops the surface temperatures of roofs and walls, which in turn reduces cooling-energy use and provides savings for the homeowner and relief for the utilities. In moderate and hot climates, a roof surface with high solar reflectance and high thermal emittance was shown by Akbari et al. (2004) and by Parker and Sherwin (1998) to reduce the exterior temperature and produce savings in comfort cooling. The new cool color pigments can potentially reduce emissions of carbon dioxide, which in turn reduces metropolitan heat buildup and urban smog. The pigments can also help conserve water resources otherwise used to clean and process fuel consumed by fossil-fuel driven power plants. Cool roofs also result in a lower ambient temperature that further decreases the need for air conditioning, retards smog formation, and improves thermal comfort. Parker, Sonne and Sherwin (2002) demonstrated that white barrel and white flat tiles reduced cooling energy consumption by 22% of the base load used by an adjacent and identical home having direct nailed dark shingles. Part of the savings was due to the reflectance of the white tiles; however, another part was due to the mass of the tile and to the venting occurring within the double batten installation. With, Cherry and Haig (2009) have studied the influence of the thermal mass and batten space ventilation and have found that, referenced to an asphalt shingle system, it can be equivalent to an additional 28 points of solar reflectivity. The double batten arrangement has wooden counter battens laid vertically (soffit-to-ridge) against the roof deck, and then the conventional battens are laid horizontally across the counter battens, providing a nailing surface for the concrete tile. This double batten construction forms an inclined air channel running from the soffit to the ridge. The bottom surface of the channel is formed by the roof decking and is relatively flat and smooth. The top surface is created by the underside of the roofing tiles, and is designed to be an air permeable covering to alleviate the underside air pressure and minimize wind uplift on the tiles. The resulting air flows also have a cooling influence which further complicates prediction of the heat penetrating through the deck because an accurate measure of the airflow is required to predict the heat transfer. Measured temperatures and heat flows at the roof surface, within the attic and at the ceiling of the houses are discussed as well as the power usage to help gauge the benefit of cool-pigmented reflective roof products fitted with and without ventilation above the roof deck. Ventilation occurring above the deck is an inherent feature for tile roof assemblies, and is formed by an air space between the exterior face of the roof sheathing and the underside of the tile. The greater the tile s profile the greater is the effect of the ventilation which herein is termed above-sheathing ventilation (ASV). However, because of the complexity of the thermally induced flow, little credit is allowed by state and federal building codes. ASHRAE (2005) provides empirical data for the effective thermal resistance of plane air spaces. A -in. (0.0191-m) plane air space inclined at 45 with the horizontal has an RUS-0.85 (RSI-0.15) . Our intent is to help further deploy cool color pigments in roofs by conducting field experiments to evaluate the new cool-colored roofing materials in the hot climate of Southern California. The collected data will be used to showcase and market the performance of new cool-roof products and also to help formulate and validate computer codes capable of calculating the heat transfer occurring within the attic and the whole building. Field measures and computer predictions showed that the d

Miller, William A [ORNL; Cherry, Nigel J [ORNL; Allen, Richard Lowell [ORNL; Childs, Phillip W [ORNL; Atchley, Jerald Allen [ORNL; Ronnen, Levinson [Lawrence Berkeley National Laboratory (LBNL); Akbari, Hashem [Lawrence Berkeley National Laboratory (LBNL); Berhahl, Paul [Lawrence Berkeley National Laboratory (LBNL)

2010-03-01

142

Thermal evaluation of advanced solar dynamic heat receiver performance  

NASA Technical Reports Server (NTRS)

The thermal performance of a variety of concepts for thermal energy storage as applied to solar dynamic applications is discussed. It is recognized that designs providing large thermal gradients or large temperature swings during orbit are susceptible to early mechanical failure. Concepts incorporating heat pipe technology may encounter operational limitations over sufficiently large ranges. By reviewing the thermal performance of basic designs, the relative merits of the basic concepts are compared. In addition the effect of thermal enhancement and metal utilization as applied to each design provides a partial characterization of the performance improvements to be achieved by developing these technologies.

Crane, Roger A.

1989-01-01

143

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) one more field test has been conducted in an underground coal mine, (2) optimization studies of the control parameters have been conducted, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (4) about 98% of the development work for the roof geology mapping program, MRGIS, has completed, (5) A real time roof geology mapping system for roof bolters in limestone mine, including a special version of the geology mapping program and hardware, has already been verified to perform very well in underground production condition.

Syd S. Peng

2005-01-15

144

Thermal Performance Testing Of Cryogenic Piping Systems  

NASA Technical Reports Server (NTRS)

Thermal performance measurement of piping systems under actual field conditions is important for space launch development and commercial industry. Knowledge of the true insulating effectiveness is needed in system design, development, and research activities. A new 18-meter-long test apparatus for cryogenic pipelines has been developed. Three different pipelines, rigid or flexible, can be tested simultaneously. Critical factors in heat leak measurements include eliminating heat transfer at end connections and obtaining proper liquid saturation condition. Effects due to variations in the external ambient conditions like wind, humidity, and solar radiation must be minimized. The static method of liquid nitrogen evaporation has been demonstrated, but the apparatus can be adapted for dynamic testing with cryogens, chilled water, or other working fluids. This technology is suited for the development of an industry standard test apparatus and method. Examples of the heat transfer data from testing commercially available pipelines are given. Prototype pipelines are currently being tested and evaluated at the Cryogenics Test Laboratory of NASA Kennedy Space Center.

Fesmire, J. E.; Augustynowicz, S. D.; Nagy, Z. F.

2003-01-01

145

Thermal Performance of the LDX Floating Coil  

NASA Astrophysics Data System (ADS)

The Levitated Dipole Experiment (LDX) is an innovative facility to study plasma confinement in a dipole magnetic field, created by a superconducting solenoid (floating coil), which is magnetically levitated in the center of a 5 m diameter by 3 m tall vacuum chamber. The floating coil (F-coil) consists of a Nb3Sn magnet installed inside a strong vessel filled with high-pressure helium gas at room temperature. It is surrounded by a fiberglass-lead composite radiation shield and by a toroidal vacuum shell. The cryostat design provides the ability to operate the magnet for several hours of wanning while suspended in the middle of the vacuum chamber without electric and cryogenic connections to the coil. For this reason the magnet is charged/discharged inductively in a lower part of the vacuum chamber. The retractable cryogenic transfer lines serve to cool down the magnet to 4.5 K before it is lifted to the operating position. The F-coil can be re-cooled multiple times while maintaining its field and current. This paper describes the thermal performance of the F-coil.

Zhukovsky, A.; Garnier, D. T.; Radovinsky, A. L.

2006-04-01

146

Mine roof geology information system  

SciTech Connect

A project sponsored by the US Department of Energy under the Industry of Future (Mining) program was initiated five years ago. In this project a patented drill control unit (DCU) installed DIN. the J.H. Flecher & Co.'s roof bolter was used to record the drilling parameter for experiments conducted in the mines and laboratory. Today, the drilling parameters have been recorded for more than 1,000 roof bolt holes. This article summarizes the results to date including the methods for determining quantitatively the location of voids/fractures and estimation of roof rock strength from the recorded roof bolter drilling parameters. 8 figs., 2 tabs.

Peng, S.S.; Sasaoka, T.; Tang, D.X.; Wilson, Y.; Wilson, G.

2005-05-01

147

40 CFR 65.43 - Fixed roof with an internal floating roof (IFR).  

Code of Federal Regulations, 2014 CFR

... false Fixed roof with an internal floating roof (IFR). 65.43 Section 65...65.43 Fixed roof with an internal floating roof (IFR). (a) IFR design requirements...by using a fixed roof and an internal floating roof shall comply with the design...

2014-07-01

148

Alkali metal\\/halide thermal energy storage systems performance evaluation  

Microsoft Academic Search

Materials compatibility and durability of advanced salt\\/alkali metal slurry thermal energy storage systems has been demonstrated. Applications are being evaluated for both space and terrestrial solar thermal power conversion. High energy density of these thermal storage systems is achieved by colocation of heat input and extraction within the slurry mixture which is overwhelmingly phase-change salt. This paper addresses performance testing

W. M. Phillips; J. W. Stearns

1987-01-01

149

The Thermal Performance of School Buildings  

ERIC Educational Resources Information Center

Attempts to compare the thermal environment measured within schools with current prediction methods and the energy used to produce and maintain the thermal environment with that predicted. Argues that a more exact definition of the external climate for design purposes is needed and suggests such a definition. (Author/EA)

O'Sullivan, P. E.; Cole, R. J.

1974-01-01

150

The Successful Transfer of Space Derived Convergent Spray: An Application for Industrial Roof Coatings and Interstate Bridge Repair  

NASA Technical Reports Server (NTRS)

A partnership was formed between the National Aeronautics and Space Administration (NASA), the Environmental Protection Agency (EPA), and United Technologies USBI Company to develop, demonstrate, and evaluate a technology that uses a solventless spray process for depositing a lightweight, highly filled roof coating on low-sloped commercial roofs. Although the levels of volatile organic compound (VOC) emissions from industrial roof coating's and paint operations have been reduced in recent years, this partnership,was an effort to further reduce VOC emission levels and to also demonstrate the use of reclaimed automobile tire rubber as a filler material in roof coating systems. Different materials and coatings were evaluated and tested before the final selection used to coat the roofs of two small buildings at NASA's Marshall Space Flight Center during fiscal year 1997. The project successfully leveraged the investment of EPA, NASA and private sector resources to demonstrate a pre-commercial roofing coating process. This process utilizes the Convergent Spray Technologies process, which was initially developed by USBI to apply highly-filled, thermal protection coatings to the Space Shuttle Solid Rocket Boosters. A second partnership between the NASA, Federal Highway Administration, Alabama Department of Transportation and USBI Company was formed to develop and demonstrate the Convergent Spray Technology as a method of applying a skid resistant coating to interstate roads and concrete bridge decking's. Again, different materials and coatings were evaluated and tested before the final selection of ground flint and resin. Two field demonstrations were performed during fiscal year 1997 for the purpose of evaluating the coating system under actual highway conditions. These coatings were applied on Interstate 65 near Huntsville Alabama, and in the Mobile Bankhead tunnel. The system performed this task without the use of harmful solvents, and accomplished the process in a single application. This project successfully leveraged the investment of NASA, Federal Highway Administration, the Alabama Department of Transportation, and private sector funding.

McMillan, Vernotto C.

1998-01-01

151

13. ONE OF TWO LATERAL ROOF TRUSSES AND ROOF SUPPORT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. ONE OF TWO LATERAL ROOF TRUSSES AND ROOF SUPPORT BEAMS OF SARATOGA GAS LIGHT COMPANY GASHOLDER NO. 2 HOUSE LOOKING WEST. THE WIRES AND BEAM AT RIGHT CENTER OF PHOTOGRAPH HAVE BEEN ADDED TO STABILIZE TRUSS SYSTEM - Saratoga Gas Light Company, Gasholder No. 2, Niagara Mohawk Power Corporation Substation Facility, intersection of Excelsior & East Avenues, Saratoga Springs, Saratoga County, NY

152

12. CENTRAL ROOF TRUSS AND ROOF SUPPORT BEAMS OF SARATOGA ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. CENTRAL ROOF TRUSS AND ROOF SUPPORT BEAMS OF SARATOGA GAS LIGHT COMPANY GASHOLDER NO. 2 HOUSE, LOOKING WEST. THE WIRES AND BEAM AT RIGHT OF PHOTOGRAPH HAVE BEEN ADDED TO STABILIZE TRUSS SYSTEM. - Saratoga Gas Light Company, Gasholder No. 2, Niagara Mohawk Power Corporation Substation Facility, intersection of Excelsior & East Avenues, Saratoga Springs, Saratoga County, NY

153

A Monolithic Microconcentrator Receiver For A Hybrid PV-Thermal System: Preliminary Performance  

NASA Astrophysics Data System (ADS)

An innovative hybrid PV-thermal microconcentrator (MCT) system is being jointly developed by Chromasun Inc., San Jose, California, and at the Centre for Sustainable Energy Systems, Australian National University. The MCT aims to develop the small-scale, roof-top market for grid-integrated linear CPV systems. A low profile, small footprint enclosure isolates system components from the environment, relaxing the demands on supporting structures, tracking, and maintenance. Net costs to the consumer are reduced via an active cooling arrangement that provides thermal energy suitable for water and space heating, ventilation, and air conditioning (HVAC) applications. As part of a simplified, low-cost design, an integrated substrate technology provides electrical interconnection, heat sinking, and mechanical support for the concentrator cells. An existing, high-efficiency, one-sun solar cell technology has been modified for this system. This paper presents an overview of the key design features, and preliminary electrical performance of the MCT. Module efficiencies of up to 19.6% at 20x concentration have been demonstrated.

Walter, D.; Everett, V.; Vivar, M.; Harvey, J.; Van Scheppingen, R.; Surve, S.; Muric-Nesic, J.; Blakers, A.

2010-10-01

154

Development of a Roof Savings Calculator  

SciTech Connect

A web-based Roof Savings Calculator (RSC) has been deployed for the Department of Energy as an industry-consensus tool to help building owners, manufacturers, distributors, contractors and researchers easily run complex roof and attic simulations. This tool employs the latest web technologies and usability design to provide an easy input interface to an annual simulation of hour-by-hour, whole-building performance using the world-class simulation tools DOE-2.1E and AtticSim. Building defaults were assigned and can provide estimated annual energy and cost savings after the user selects nothing more than building location. In addition to cool reflective roofs, the RSC tool can simulate multiple roof types at arbitrary inclinations. There are options for above sheathing ventilation, radiant barriers, and low-emittance surfaces. The tool also accommodates HVAC ducts either in the conditioned space or in the attic with custom air leakage rates. Multiple layers of building materials, ceiling and deck insulation, and other parameters can be compared side-by-side to generate an energy/cost savings estimate between two buildings. The RSC tool was benchmarked against field data for demonstration homes in Ft. Irwin, CA.

New, Joshua Ryan [ORNL] [ORNL; Miller, William A [ORNL] [ORNL; Desjarlais, Andre Omer [ORNL] [ORNL; Erdem, Ender [Lawrence Berkeley National Laboratory (LBNL)] [Lawrence Berkeley National Laboratory (LBNL); Huang, Joe [Lawrence Berkeley National Laboratory (LBNL)] [Lawrence Berkeley National Laboratory (LBNL)

2011-01-01

155

Energy saving potential of various roof technologies  

E-print Network

Unconventional roof technologies such as cool roofs and green roofs have been shown to reduce building heating and cooling load. Although previous studies suggest potential for energy savings through such technologies, ...

Ray, Stephen D. (Stephen Douglas)

2010-01-01

156

Effects of Solar Photovoltaic Panels on Roof Heat Transfer  

NASA Technical Reports Server (NTRS)

Building Heating, Ventilation and Air Conditioning (HVAC) is a major contributor to urban energy use. In single story buildings with large surface area such as warehouses most of the heat enters through the roof. A rooftop modification that has not been examined experimentally is solar photovoltaic (PV) arrays. In California alone, several GW in residential and commercial rooftop PV are approved or in the planning stages. With the PV solar conversion efficiency ranging from 5-20% and a typical installed PV solar reflectance of 16-27%, 53-79% of the solar energy heats the panel. Most of this heat is then either transferred to the atmosphere or the building underneath. Consequently solar PV has indirect effects on roof heat transfer. The effect of rooftop PV systems on the building roof and indoor energy balance as well as their economic impacts on building HVAC costs have not been investigated. Roof calculator models currently do not account for rooftop modifications such as PV arrays. In this study, we report extensive measurements of a building containing a flush mount and a tilted solar PV array as well as exposed reference roof. Exterior air and surface temperature, wind speed, and solar radiation were measured and thermal infrared (TIR) images of the interior ceiling were taken. We found that in daytime the ceiling surface temperature under the PV arrays was significantly cooler than under the exposed roof. The maximum difference of 2.5 C was observed at around 1800h, close to typical time of peak energy demand. Conversely at night, the ceiling temperature under the PV arrays was warmer, especially for the array mounted flat onto the roof. A one dimensional conductive heat flux model was used to calculate the temperature profile through the roof. The heat flux into the bottom layer was used as an estimate of the heat flux into the building. The mean daytime heat flux (1200-2000 PST) under the exposed roof in the model was 14.0 Watts per square meter larger than under the tilted PV array. The maximum downward heat flux was 18.7 Watts per square meters for the exposed roof and 7.0 Watts per square meters under the tilted PV array, a 63% reduction due to the PV array. This study is unique as the impact of tilted and flush PV arrays could be compared against a typical exposed roof at the same roof for a commercial uninhabited building with exposed ceiling and consisting only of the building envelope. Our results indicate a more comfortable indoor environment in PV covered buildings without HVAC both in hotter and cooler seasons.

Dominguez, A.; Klessl, J.; Samady, M.; Luvall, J. C.

2010-01-01

157

Performance of a solar-thermal collector  

NASA Technical Reports Server (NTRS)

Possible means of achieving the technology required for field application of solar thermal power systems are discussed. Simplifications in construction techniques as well as in measurement techniques for parabolic trough collectors are described. Actual measurement data is also given.

Higa, W. H.

1975-01-01

158

How Cool Is Your Roof?  

ERIC Educational Resources Information Center

Explains a concept called cool roof that is used to reduce electricity costs for air conditioning, and also reduce the price of air conditioning units. Discusses the light reflecting capabilities of metal roofing as well as coatings that can stop leaks. (GR)

Fickes, Michael

2001-01-01

159

Performance evaluation of floor thermal storage system  

SciTech Connect

Environmental issues were seriously addressed when a new building was designed with district heating and cooling for the Osaka gas company. As a result, the building was officially recognized as Environmentally Conscious Building No. 1 by the Construction Ministry. In order to reduce cost by peak shaving, adoption of a floor thermal storage system was planned. This paper describes results regarding the peak shaving by floor thermal storage system in designing the air-conditioning system.

Shinkai, Koichiro; Kasuya, Atsushi; Kato, Masahiro

2000-07-01

160

The thermal performance of solar water heaters in the UK  

Microsoft Academic Search

As a contribution to the preparation of a code of practice by the British Standards Institution technical committee on solar water heaters, the long-term thermal performance of domestic solar water heaters has been estimated, using a computer program developed at Thornton Research Centre. This model is described, and results are presented showing the effect on thermal performance of varying some

J. L. J. Rosenfeld

1979-01-01

161

Development of thermal performance criteria for residential passive solar buildings  

Microsoft Academic Search

In support of the development of thermal performance criteria for residential passive solar buildings, thermal design characteristics and anticipated performance for 266 projects in the HUD Passive Residential Design Competition and the HUD Cycle 5 Demonstration Program were analyzed. These passive residences are located in all regions of the United States requiring space heating, and they represent a variety of

P. A. Sabatiuk; D. E. Cassel; M. McCabe; C. Scarbrough

1980-01-01

162

Measuring mine roof bolt strains  

DOEpatents

A mine roof bolt and a method of measuring the strain in mine roof bolts of this type are disclosed. According to the method, a flat portion on the head of the mine roof bolt is first machined. Next, a hole is drilled radially through the bolt at a predetermined distance from the bolt head. After installation of the mine roof bolt and loading, the strain of the mine roof bolt is measured by generating an ultrasonic pulse at the flat portion. The time of travel of the ultrasonic pulse reflected from the hole is measured. This time of travel is a function of the distance from the flat portion to the hole and increases as the bolt is loaded. Consequently, the time measurement is correlated to the strain in the bolt. Compensation for various factors affecting the travel time are also provided.

Steblay, Bernard J. (Lakewood, CO)

1986-01-01

163

Thermal performance of a small oil-in-glass tube thermal energy storage system during charging  

Microsoft Academic Search

A very small oil-in-glass tube thermal energy storage (TES) system is designed to allow for rapid heat transfer experiments. An electrical hot plate in thermal contact with a steel spiral coil (SSC) is used to charge the TES system under different hot plate temperatures and under different average charging flow rates. Thermal performance during charging is presented in terms of

A. Mawire; M. McPherson; R. R. J. van den Heetkamp

2009-01-01

164

Proceedings of Thermal VII, Thermal Performance of the Exterior Envelopes of Buildings,  

E-print Network

LBNL-42871 BS-400 Proceedings of Thermal VII, Thermal Performance of the Exterior Envelopes locations. The user describes the physical, thermal and optical properties of the windows in each orientation, solar heat gain reductions due to obstructions, overhangs, or shades, and the location

165

Cost and performance of thermal storage concepts in solar thermal systems  

Microsoft Academic Search

Consistently calculated cost data was calculated, realistic performance data developed, and projected and for a mature technology for several thermal storage concepts integrated into several solar thermal systems. Available thermal storage concepts were reviewed. A screening criteria was developed which when applied, resulted in forty systems being judged suitable for further study. Schematics were made for these systems, quantities were

A. W. McKenzie

1982-01-01

166

Cost and performance of thermal storage concepts in solar thermal systems  

Microsoft Academic Search

Studies to provide consistently calculated cost data, develop realistic performance data, and to project data for several thermal storage concepts integrated into several solar thermal systems are summarized. Available thermal storage concepts were reviewed through a literature search, contacts, and contractors. A screening criteria was developed and schematics were made for these systems. Rough-order-of-magnitude costs were determined and candidate systems

A. W. McKenzie

1981-01-01

167

Investigation of the Mechanical Performance of Compliant Thermal Barriers  

NASA Technical Reports Server (NTRS)

Compliant thermal barriers play a pivotal role in the thermal protection systems of advanced aerospace vehicles. Both the thermal properties and mechanical performance of these barriers are critical in determining their successful implementation. Due to the custom nature of many thermal barriers, designers of advanced spacecraft have little guidance as to the design, selection, and implementation of these elements. As part of an effort to develop a more fundamental understanding of the interrelationship between thermal barrier design and performance, mechanical testing of thermal barriers was conducted. Two different types of thermal barriers with several core insulation density levels ranging from 62 to 141 kg/cu m were investigated. Room-temperature compression tests were conducted on samples to determine load performance and assess thermal barrier resiliency. Results showed that the loading behavior of these thermal barriers was similar to other porous, low-density, compliant materials, such as elastomeric foams. Additionally, the insulation density level had a significant non-linear impact on the stiffness and peak loads of the thermal barriers. In contrast, neither the thermal barrier type nor the level of insulation density significantly influenced the room-temperature resiliency of the samples.

DeMange, Jeffrey J.; Bott, Robert J.; Dunlap, Patrick H.

2011-01-01

168

Composite Materials for Thermal Energy Storage: Enhancing Performance through Microstructures  

PubMed Central

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. PMID:24591286

Ge, Zhiwei; Ye, Feng; Ding, Yulong

2014-01-01

169

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

PubMed

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. PMID:24591286

Ge, Zhiwei; Ye, Feng; Ding, Yulong

2014-05-01

170

Extending Our Understanding of Compliant Thermal Barrier Performance  

NASA Technical Reports Server (NTRS)

Thermal barriers and seals are integral components in the thermal protection systems (TPS) of nearly all aerospace vehicles. They are used to minimize the flow of hot gases through interfaces and protect underlying temperature-sensitive components and systems. Although thermal barriers have been used extensively on many aerospace vehicles, the factors affecting their thermal and mechanical performance are not well-understood. Because of this, vehicle TPS designers are often left with little guidance on how to properly design and optimize these barriers. An ongoing effort to better understand thermal barrier performance and develop models and design tools is in progress at the NASA Glenn Research Center. Testing has been conducted to understand the degree to which insulation density influences structural performance and permeability. In addition, the development of both thermal and mechanical models is ongoing with the goal of providing an improved ability to design and implement these critical TPS components.

Demange, Jeffrey J.; Finkbeiner, Joshua R.; Dunlap, Patrick H.

2014-01-01

171

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. Field tests have been performed in two underground coal mines in this quarter. It also found from the tests that the non-drilling thrust and torque should be deducted from the acquired drilling data. The non-drilling torque is actually higher than that is used to overcome the shear strength is proportional to the rotation rate.

Syd S. Peng

2002-07-15

172

Demonstration of Cooling Savings of Light Colored Roof Surfacing in Florida Commercial Buildings: Our Savior's School.  

ERIC Educational Resources Information Center

A 2-year Florida study attempted to quantify air conditioning cost savings when buildings have a white reflective roof. A 10,000 square foot elementary school with a gray modified bitumen roof over plywood decking that had a solar reflectance of 23 percent was monitored for an entire year. After one year of building thermal conditions and…

Parker, Danny S.; Sherwin, John R.; Sonne, Jeffrey K.; Barkaszi, Stephen F., Jr.

173

Hydrological Modelling and Parameter Identification for Green Roof  

NASA Astrophysics Data System (ADS)

Green roofs, a multilayered system covered by plants, can be used to replace traditional concrete roofs as one of various measures to mitigate the increasing stormwater runoff in the urban environment. Moreover, facing the high uncertainty of the climate change, the present engineering method as adaptation may be regarded as improper measurements; reversely, green roofs are unregretful and flexible, and thus are rather important and suitable. The related technology has been developed for several years and the researches evaluating the stormwater reduction performance of green roofs are ongoing prosperously. Many European counties, cities in the U.S., and other local governments incorporate green roof into the stormwater control policy. Therefore, in terms of stormwater management, it is necessary to develop a robust hydrologic model to quantify the efficacy of green roofs over different types of designs and environmental conditions. In this research, a physical based hydrologic model is proposed to simulate water flowing process in the green roof system. In particular, the model adopts the concept of water balance, bringing a relatively simple and intuitive idea. Also, the research compares the two methods in the surface water balance calculation. One is based on Green-Ampt equation, and the other is under the SCS curve number calculation. A green roof experiment is designed to collect weather data and water discharge. Then, the proposed model is verified with these observed data; furthermore, the parameters using in the model are calibrated to find appropriate values in the green roof hydrologic simulation. This research proposes a simple physical based hydrologic model and the measures to determine parameters for the model.

Lo, W.; Tung, C.

2012-12-01

174

Space Shuttle Orbiter - Reusable surface insulation subsystem thermal performance  

NASA Technical Reports Server (NTRS)

The thermal performance of the reusable surface insulation (RSI) subsystem consisting of silica tiles, silicone coated nylon felt insulation, and ceramic cloth gap fillers and thermal barriers is discussed. Thermal response predictions for the components are compared with measured flight data, which indicates that the RSI thermal performance can meet or exceed design requirements for the majority of the RSI. Visual inspections and the maximum temperature conditions observed in structural components after data acquisition suggest that the flight environment was not as severe as the worst case preflight prediction.

Dotts, R. L.; Battley, H. H.; Hughes, J. T.; Neuenschwander, W. E.

1982-01-01

175

Thermal performance representation and testing of air solar collectors  

Microsoft Academic Search

The thermal performance of a plate-type air collector was evaluated experimentally. Tests were performed at the two ASHRAE Standard 93-1986 recommended flowrates and at a variety of inlet gage pressures to cover the three possible cases of collector leakage (inward, outward, inward-outward). These tests show that the thermal performance of air collectors depends on flowrate and inlet gage pressure (or

M. A. Bernier; E. G. Plett

1988-01-01

176

Thermal Performance of an Annealed Pyrolytic Graphite Solar Collector  

NASA Technical Reports Server (NTRS)

A solar collector having the combined properties of high solar absorptance, low infrared emittance, and high thermal conductivity is needed for applications where solar energy is to be absorbed and transported for use in minisatellites. Such a solar collector may be used with a low temperature differential heat engine to provide power or with a thermal bus for thermal switching applications. One concept being considered for the solar collector is an Al2O3 cermet coating applied to a thermal conductivity enhanced polished aluminum substrate. The cermet coating provides high solar absorptance and the polished aluminum provides low infrared emittance. Annealed pyrolytic graphite embedded in the aluminum substrate provides enhanced thermal conductivity. The as-measured thermal performance of an annealed pyrolytic graphite thermal conductivity enhanced polished aluminum solar collector, coated with a cermet coating, will be presented.

Jaworske, Donald A.; Hornacek, Jennifer

2002-01-01

177

Stormwater runoff mitigation and nutrient leaching from a green roof designed to attract native pollinating insects  

NASA Astrophysics Data System (ADS)

A green roof is typically installed for one of two reasons: to mitigate the 'urban heat island' effect, reducing ambient temperatures and creating energy savings, or to reduce both the quantity and intensity of stormwater runoff, which is a major cause of river erosion and eutrophication. The study of green roofs in the United States has focused on commercial systems that use a proprietary expanded shale or clay substrate, along with succulent desert plants (mainly Sedum species). The green roof has the potential not only to provide thermal insulation and reduce storm runoff, but also to reclaim some of the natural habitat that has been lost to the built environment. Of special importance is the loss of habitat for pollinating insects, particularly native bees, which have been in decline for at least two decades. These pollinators are essential for crop production and for the reproduction of at least 65% of wild plants globally. Our study involves the installation of a small (4ft by 4ft), self-designed green roof system built with readily available components from a hardware store. The garden will be filled with a soilless potting mix, combined with 15% compost, and planted with grasses and wildflowers native to the Seacoast, New Hampshire region. Some of the plant species are used by bees for nesting materials, while others provide food in the form of nectar, pollen, and seeds for bees, butterflies, hummingbirds, and granivorous birds. We monitor precipitation on the roof and runoff from the garden on a per storm basis, and test grab samples of runoff for dissolved organic nitrogen and phosphorous. Runoff and nutrient concentration results are compared to a non-vegetated roof surface, and a proprietary Green Grid green roof system. This project is designed to address three main questions of interest: 1) Can these native plant species, which potentially provide greater ecosystem services than Sedum spp. in the form of food and habitat, survive in the conditions on a rooftop? 2) How does this design compare with the performance of the extant Green Grid green roof system on the roof in regard to storm water runoff mitigation and nutrient leaching? and 3) Using GIS, can this information be scaled to a larger region (i.e. UNH campus, the NH Seacoast, NH cities, etc.) to determine areas of particular interest for pollinator conservation? Runoff mitigation, as a percentage of precipitation, is expected to be greater than that on the roof with proprietary substrate, though nutrient leaching may be greater as well due to the higher organic matter content. Paired with GIS data on NH ecoregions, these results will help to identify areas in the state that would benefit from the construction of pollinator habitat corridors, including urban areas that may not have been previously considered.

Fogarty, S.; Grogan, D. S.; Hale, S. R.

2013-12-01

178

Thermal management system for high performance PowerPCTM microprocessors  

Microsoft Academic Search

Thermal management is an important design issue in high-performance, low-power portable computers. If the computer system is designed for worst-case processor power dissipation and environmental operating conditions, it carries an area and cost penalty for the system designer. The next-generation PowerPCTM microprocessor includes a thermal assist unit (TAU) comprised of an on-chip thermal sensor and associated logic. The TAU monitors

Hector Sanchez; Belli Kuttanna; Tim Olson; Mike Alexander; Gian Gerosa; Ross Philip; Jose Alvarez

1997-01-01

179

Window performance for human thermal comfort  

SciTech Connect

A method based on the ASHRAE two-node comfort model has been developed for predicting the effect of windows on thermal comfort. The method embodies separate analyses for longwave (thermal infrared) radiation, induced drafts, and solar load effects. Of these three impacts, modeling results demonstrate that longwave exchange between the body and the window is the most significant except for the case where the body is in direct sun, in which case the impact of solar load can be more significant. For most residential-sized windows, draft effects exist but are typically small. Generally, windows are not the primary element affecting the comfort of a building's occupants. However, when a window is very hot or cold, the occupant is very close to the window; or other factors result in thermal conditions near the edge of the comfort zone, windows can become quite influential. Furthermore, it is believed that current methods may underpredict discomfort caused by windows. The authors discuss potential refinements to the method that might address this inaccuracy by accounting for asymmetries in radiant temperature. In the near term, the model could be used to create a simplified window comfort index. To accompany the index, they envision educational material that would educate designers and consumers on the comfort implications of glazing selection.

Lyons, P.R.; Arasteh, D.; Huizenga, C.

2000-07-01

180

Thermal performance of concrete masonry unit wall systems  

SciTech Connect

New materials, modern building wall technologies now available in the building marketplace, and unique, more accurate, methods of thermal analysis of wall systems create an opportunity to design and erect buildings where thermal envelopes that use masonry wall systems can be more efficient. Thermal performance of the six masonry wall systems is analyzed. Most existing masonry systems are modifications of technologies presented in this paper. Finite difference two-dimensional and three-dimensional computer modeling and unique methods of the clear wall and overall thermal analysis were used. In the design of thermally efficient masonry wall systems is t to know how effectively the insulation material is used and how the insulation shape and its location affect the wall thermal performance. Due to the incorrect shape of the insulation or structural components, hidden thermal shorts cause additional heat losses. In this study, the thermal analysis of the clear wall was enriched with the examination of the thermal properties of the wall details and the study of a quantity defined herein the Thermal Efficiency of the insulation material.

Kosny, J.

1995-12-31

181

Dynamic Thermal Management for High-Performance Microprocessors  

Microsoft Academic Search

With the increasing clock rate and transistor count of to- day's microprocessors, power dissipation is becoming a critical component of system design complexity. Thermal and power-delivery issues are becoming especially critical for high-performance computing systems. In this work, we investigate dynamic thermal manage- ment as a technique to control CPU power dissipation. With the increasing usage of clock gating techniques,

David Brooks; Margaret Martonosi

2001-01-01

182

Investigation of Hydrothermal Performance of Fibrous Thermal Insulation Materials  

Microsoft Academic Search

The hydrothermal performance of fibrous thermal insulation materials is dictated by the response of the system to combined heat, air and moisture fluctuations produced by exterior and interior conditions that exist on either side of the materials. This paper reports on experimental results to assess the drying and wetting rate of fibrous thermal insulation materials in close contact with various

A. Endriukaityt?; R. Bli?d ius; R. Samajauskas

183

Thermal Insulation Performance in the Process Industries: Facts and Fallacies  

E-print Network

THERMAL INSULATION PERFORMANCE IN 'mE PROCESS INDUSTRIES: FACTS AND FALLACIES R.P. Tye Dynatech RID Company, Cambridge, MA, U.S.A. ABSTRACT The efficient use of thermal insulation materials and systems for design of cryogenic and elevated...

Tye, R. P.

184

LCP heater thermal performance test results and unique test techniques  

SciTech Connect

The Large Coil Program (LCP) magnet requires integral heaters capable of normalizing conductor half-turns to simulate energy deposition. During a series of tests to determine the cryogenic thermal performance of our LCP conductor, we evaluated the relative thermal performance of two prototype heater installation methods which were tested using a unique heater power control circuit. The prototype heaters were installed in two LCP conductors which were part of a 15-conductor test array used during the conductor thermal performance testing. Results are given comparing the thermal performance of the two heaters, one installed with indium foil and the other soldered with Woods metal. The performance of the Woods metal installation agreed closely to the finite element model predicted conductor thermal response to fast, high-power heater pulses, both in maximum temperature rise and time characteristics of the rise and recovery. The sluggish thermal response of the conductor with the cold-welded indium ribbon-secured heater demonstrated that intimate thermal coupling of the heater elements to the conductor is mandatory. The heater control circuitry is described which was developed in support of this test and provided transient heater power durations down to 5 msec and at power inputs up to 3000 watts. A brief description also is given of the transient and steady-state data acquisition systems used as well as the interface between the heater control circuitry and the remote computer used to control the transient testing.

Bailey, R.E.; Christensen, E.H.

1980-01-01

185

TOWARDS STANDARDIZATION OF SERVICE LIFE PREDICTION OF ROOFING MEMBRANES  

Microsoft Academic Search

A service life prediction approach for roofing membranes and systems is proposed based on a probabilistic modeling of the time-dependent performance. The membrane performance is modeled using a discrete Markov chain that evaluates the change of performance over time as a result of deterioration or repair. The transition probability matrix will be developed using in-field performance data collected during consecutive

Zoubir Lounis; Michael A. Lacasse; Dana J. Vanier; Brian R. Kyle

186

Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance  

NASA Technical Reports Server (NTRS)

This presentation describes the capabilities of three-dimensional thermal power model of advanced stirling radioisotope generator (ASRG). The performance of the ASRG is presented for different scenario, such as Venus flyby with or without the auxiliary cooling system.

Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

2014-01-01

187

Study on evaporative cooling effect of roof lawn gardens  

Microsoft Academic Search

In a very hot climate equivalent to a Japanese summer, the reduction of heat coming into rooms is very important with respect to thermal comfort and energy efficiency. The objective of this study is to investigate the evaporative cooling effect from roof lawn gardens planted in non-woven fabric as one mode of passive cooling. It was confirmed by field measurements

S Onmura; M Matsumoto; S Hokoi

2001-01-01

188

The effect of DEB powder processing on thermal cell performance  

Microsoft Academic Search

During the last twenty years, the system Ca\\/LiCl-KCl-CaCrO4\\/Fe has provided the basis for thermal batteries designed for military applications. In connection with greater performance demands, investigations are being conducted concerning the effect of catholyte processing on thermal cell performance. The catholyte layer is composed of three components including the depolarizer (D), CaCrO4, the electrolyte (E), LiCl-KCl eutectic, and the binder

R. Szwarc; R. D. Walton

1981-01-01

189

Thermal Components Boost Performance of HVAC Systems  

NASA Technical Reports Server (NTRS)

As the International Space Station (ISS) travels 17,500 miles per hour, normal is having a constant sensation of free-falling. Normal is no rain, but an extreme amount of shine.with temperatures reaching 250 F when facing the Sun. Thanks to a number of advanced control systems onboard the ISS, however, the interior of the station remains a cool, comfortable, normal environment where astronauts can live and work for extended periods of time. There are two main control systems on the ISS that make it possible for humans to survive in space: the Thermal Control System (TCS) and the Environmental Control and Life Support system. These intricate assemblies work together to supply water and oxygen, regulate temperature and pressure, maintain air quality, and manage waste. Through artificial means, these systems create a habitable environment for the space station s crew. The TCS constantly works to regulate the temperature not only for astronauts, but for the critical instruments and machines inside the spacecraft as well. To do its job, the TCS encompasses several components and systems both inside and outside of the ISS. Inside the spacecraft, a liquid heat-exchange process mechanically pumps fluids in closed-loop circuits to collect, transport, and reject heat. Outside the ISS, an external system circulates anhydrous ammonia to transport heat and cool equipment, and radiators release the heat into space. Over the years, NASA has worked with a variety of partners.public and private, national and international. to develop and refine the most complex thermal control systems ever built for spacecraft, including the one on the ISS.

2012-01-01

190

Green roof soil system affected by soil structural changes: A project initiation  

NASA Astrophysics Data System (ADS)

Anthropogenic soil systems and structures such as green roofs, permeable or grassed pavements comprise appreciable part of the urban watersheds and are considered to be beneficial regarding to numerous aspects (e.g. carbon dioxide cycle, microclimate, reducing solar absorbance and storm water). Expected performance of these systems is significantly affected by water and heat regimes that are primarily defined by technology and materials used for system construction, local climate condition, amount of precipitation, the orientation and type of the vegetation cover. The benefits and potencies of anthropogenic soil systems could be considerably threatened in case when exposed to structural changes of thin top soil layer in time. Extensive green roof together with experimental green roof segment was established and advanced automated monitoring system of micrometeorological variables was set-up at the experimental site of University Centre for Energy Efficient Buildings as an interdisciplinary research facility of the Czech Technical University in Prague. The key objectives of the project are (i) to characterize hydraulic and thermal properties of soil substrate studied, (ii) to establish seasonal dynamics of water and heat in selected soil systems from continuous monitoring of relevant variables, (iii) to detect structural changes with the use of X-ray Computed Tomography, (iv) to identify with the help of numerical modeling and acquired datasets how water and heat dynamics in anthropogenic soil systems are affected by soil structural changes. Achievements of the objectives will advance understanding of the anthropogenic soil systems behavior in conurbations with the temperate climate.

Jelínková, Vladimíra; Dohnal, Michal; Šácha, Jan; Šebestová, Jana; Sn?hota, Michal

2014-05-01

191

ATST enclosure: seeing performance, thermal modeling, and error budgets  

NASA Astrophysics Data System (ADS)

The enclosure for the Advanced Technology Solar Telescope (ATST) is both a wind shield and a source of seeing. Its design must minimize self-induced seeing while remaining within cost constraints and balancing with other error budget items. We report the methods used to quantify seeing performance, including thermal modeling, seeing estimation, and systems engineering error budgets. Thermal modeling is performed using a commercial software package that applies measured site weather data to a CAD-generated enclosure model. Seeing estimation is performed using a simple aerodynamic treatment. The results, along with measured site wind and temperature distributions, are combined into a "bottom-up" performance prediction using Monte Carlo techniques.

Dalrymple, Nathan E.; Oschmann, Jacobus M., Jr.; Hubbard, Robert P.

2004-09-01

192

Statistical Building Roof Reconstruction from WORLDVIEW-2 Stereo Imagery  

NASA Astrophysics Data System (ADS)

3D building reconstruction from point clouds is an active research topic in remote sensing, photogrammetry and computer vision. Most of the prior research has been done on 3D building reconstruction from LiDAR data which means high resolution and dense data. The interest of this work is 3D building reconstruction from Digital Surface Models (DSM) of stereo image matching of space borne satellite data which cover larger areas than LiDAR datasets in one data acquisition step and can be used also for remote regions. The challenging problem is the noise of this data because of low resolution and matching errors. In this paper, a top-down and bottom-up method is developed to find building roof models which exhibit the optimum fit to the point clouds of the DSM. In the bottom up step of this hybrid method, the building mask and roof components such as ridge lines are extracted. In addition, in order to reduce the computational complexity and search space, roofs are classified to pitched and flat roofs as well. Ridge lines are utilized to estimate the roof primitives from a building library such as width, length, positions and orientation. Thereafter, a topdown approach based on Markov Chain Monte Carlo and simulated annealing is applied to optimize roof parameters in an iterative manner by stochastic sampling and minimizing the average of Euclidean distance between point cloud and model surface as fitness function. Experiments are performed on two areas of Munich city which include three roof types (hipped, gable and flat roofs). The results show the efficiency of this method in even for this type of noisy datasets.

Partovi, T.; Huang, H.; Krauß, T.; Mayer, H.; Reinartz, P.

2015-03-01

193

EMC effects of the lightning protection system: shielding properties of the roof-grid  

Microsoft Academic Search

A suitable set of parameters is used to evaluate the shielding performance of the roof-grid constituted by a mesh of conductors, electrically interconnected, laying on top of buildings with a large-area roof. The influence of the roof-grid on the electromagnetic field inside the building due to a direct lightning strike is shown. The values of the electromotive force induced in

S. Cristina; A. Orlandi

1991-01-01

194

The Effects of Infrared-Blocking Pigments and Deck Venting on Stone-Coated Metal Residential Roofs  

SciTech Connect

Field data show that stone-coated metal shakes and S-mission tile, which exploit the use of infraredblocking color pigments (IrBCPs), along with underside venting reduce the heat flow penetrating the conditioned space of a residence by 70% compared with the amount of heat flow penetrating roofs with conventional asphalt shingles. Stone-coated metal roof products are typically placed on battens and counter-battens and nailed through the battens to the roof deck. The design provides venting on the underside of the metal roof that reduces the heat flow penetrating a home. The Metal Construction Association (MCA) and its affiliate members installed stone-coated metal roofs with shake and S-mission tile profiles and a painted metal shake roof on a fully instrumented attic test assembly at Oak Ridge National Laboratory (ORNL). Measurements of roof, deck, attic, and ceiling temperatures; heat flows; solar reflectance; thermal emittance; and ambient weather were recorded for each of the test roofs and also for an adjacent attic cavity covered with a conventional pigmented and direct nailed asphalt shingle roof. All attic assemblies had ridge and soffit venting; the ridge was open to the underside of the stone-coated metal roofs. A control assembly with a conventional asphalt shingle roof was used for comparing deck and ceiling heat transfer rates.

Miller, William A [ORNL

2006-01-01

195

Electrical, Frequency and Thermal Measurement and Modelling of Supercapacitor Performance  

Microsoft Academic Search

This paper presents an evaluation of commercial supercapacitors performance (ESR, C, self-discharge, Pmax, Emax, coulumbic efficiency, etc), under different conditi ons. Characterization of supercapacitor performances as a function of current, voltage, frequency and thermal constraints, is carried out by constant current test, electrochemical imped ance spectroscopy, and voltamperometry. A comparative study of measurement techniques is conducted in detail in this

Yasser Diab; Pascal Venet; Hamid Gualous; Gerard Rojat

2008-01-01

196

Thermal degradation and fire performance of polysilazane-based coatings  

Microsoft Academic Search

This paper deals with the thermal degradation and fire performance of polysilazane (PZane) based coatings. PZanes are silicon–nitrogen backbone polymers and can be used in a wide range of applications. In this study, the fire performance of PZane coating as virgin or formulated materials were evaluated using a homemade fire testing methodology similar to the “Torch Test” fire testing method.

B. Gardelle; S. Duquesne; C. Vu; S. Bourbigot

2011-01-01

197

Advances in Plexcore active layer technology systems for organic photovoltaics: roof-top and accelerated lifetime analysis of high performance organic photovoltaic cells  

NASA Astrophysics Data System (ADS)

We report NREL-certified efficiencies and initial lifetime data for organic photovoltaic (OPV) cells based on Plexcore PV photoactive layer and Plexcore HTL-OPV hole transport layer technology. Plexcore PV-F3, a photoactive layer OPV ink, was certified in a single-layer OPV cell at the National Renewable Energy Laboratory (NREL) at 5.4%, which represents the highest official mark for a single-layer organic solar cell. We have fabricated and measured P3HT:PCBM solar cells with a peak efficiency of 4.4% and typical efficiencies of 3 - 4% (internal, NREL-calibrated measurement) with P3HT manufactured at Plextronics by the Grignard Metathesis (GRIM) method. Outdoor and accelerated lifetime testing of these devices is reported. Both Plexcore PV-F3 and P3HT:PCBM-based OPV cells exhibit >750 hours of outdoor roof-top, non-accelerated lifetime with less than 8% loss in initial efficiency for both active layer systems when exposed continuously to the climate of Western Pennsylvania. These devices are continuously being tested to date. Accelerated testing using a high-intensity (1000W) metal-halide lamp affords shorter lifetimes; however, the true acceleration factor is still to be determined.

Laird, Darin W.; Vaidya, Swanand; Li, Sergey; Mathai, Mathew; Woodworth, Brian; Sheina, Elena; Williams, Shawn; Hammond, Troy

2007-09-01

198

Thermal performance of steel-framed walls. Final report  

SciTech Connect

In wall construction, highly conductive members spaced along the wall, which allow higher heat transfer than that through less conductive areas, are referred to as thermal bridges. Thermal bridges in walls tend to increase heat loss and, under certain adverse conditions, can cause dust streaking (``ghosting``) on interior walls over studs due to temperature differentials, as well as condensation in and on walls. Although such adverse conditions can be easily avoided by proper thermal design of wall systems, these effects have not been well understood and thermal data has been lacking. Therefore, the present study was initiated to provide (1) a better understanding of the thermal behavior of steel-framed walls, (2) a set of R-values for typical wall constructions, and (3) information that could be used to develop improved methods of predicting R-values. An improved method for estimating R-value would allow an equitable comparison of thermal performance with other construction types and materials. This would increase the number of alternative materials for walls available to designers, thus allowing them to choose the optimum choice for construction. Twenty-three wall samples were tested in a calibrated hot box (ASTM C9761) to measure the thermal performance of steel-framed wall systems. The tests included an array of stud frame configurations, exterior sheathing and fiberglass batt insulations. Other studies have not included the use of insulating sheathing, which reduces the extent of the thermal bridges and improves total thermal performance. The purpose of the project was to provide measured R-values for commonly used steel-framed wall configurations and to improve R-value estimating methods. Test results were compared to R-value estimates using the parallel path method, the isothermal planes method and the ASHRAE Zone method. The comparison showed that the known procedures do not fully account for the three-dimensional effects created by steel framing in a wall.

Barbour, E. [NAHB Research Center, Inc., Upper Marlboro, MD (United States); Goodrow, J. [Holometrix, Inc., Bedford, MA (United States); Kosny, J.; Christian, J.E. [Oak Ridge National Lab., TN (United States)

1994-11-21

199

Sustainable Retrofit of Residential Roofs Using Metal Roofing Panels, Thin-Film Photovoltaic Laminates, and PCM Heat Sink Technology  

SciTech Connect

During September-October 2009, research teams representing Metal Construction Association (the largest North American trade association representing metal building manufacturers, builders, and material suppliers), CertainTeed (one of the largest U.S. manufacturers of thermal insulation and building envelope materials), Unisolar (largest U.S. producer of amorphous silicone photo-voltaic (PV) laminates), Phase Change Energy (manufacturer of bio-based PCM), and Oak Ridge National Laboratory (ORNL) installed three experimental attics utilizing different roof retrofit strategies in the ORNL campus. The main goal of this project was experimental evaluation of a newly-developed sustainable re-roofing technology utilizing amorphous silicone PV laminates integrated with metal roof and PCM heat sink. The experimental attic with PV laminate was expected to work during the winter time as a passive solar collector with PCM storing solar heat, absorbed during the day, and increasing overall attic air temperature during the night.

Kosny, Jan [ORNL] [ORNL; Miller, William A [ORNL] [ORNL; Childs, Phillip W [ORNL] [ORNL; Biswas, Kaushik [ORNL] [ORNL

2011-01-01

200

System performance modeling of extreme ultraviolet lithographic thermal issues  

SciTech Connect

Numerical simulation is used in the development of an extreme ultraviolet lithography Engineering Test Stand. Extensive modeling was applied to predict the impact of thermal loads on key lithographic parameters such as image placement error, focal shift, and loss of CD control. We show that thermal issues can be effectively managed to ensure that their impact on lithographic performance is maintained within design error budgets. (c) 1999 American Vacuum Society.

Spence, P. A. [Sandia National Laboratories, Livermore, California 94551 (United States)] [Sandia National Laboratories, Livermore, California 94551 (United States); Gianoulakis, S. E. [Sandia National Laboratories, Livermore, California 94551 (United States)] [Sandia National Laboratories, Livermore, California 94551 (United States); Moen, C. D. [Sandia National Laboratories, Livermore, California 94551 (United States)] [Sandia National Laboratories, Livermore, California 94551 (United States); Kanouff, M. P. [Sandia National Laboratories, Livermore, California 94551 (United States)] [Sandia National Laboratories, Livermore, California 94551 (United States); Fisher, A. [Sandia National Laboratories, Livermore, California 94551 (United States)] [Sandia National Laboratories, Livermore, California 94551 (United States); Ray-Chaudhuri, A. K. [Sandia National Laboratories, Livermore, California 94551 (United States)] [Sandia National Laboratories, Livermore, California 94551 (United States)

1999-11-01

201

Rigid Tile Thermal Protection Materials Research and Space Shuttle Performance  

NASA Technical Reports Server (NTRS)

The materials research activities and materials characterization capabilities of the Thermal Protection Materials and Systems Branch at Ames Research Center will be described. The Branch's activities involved with the development of several parts of the thermal protection system on the Space Shuttle and their performance will be reviewed. The status of materials research in rigid light weight insulations and the potential of a newer generation of thermal protection materials designated as Toughened Uni-Piece Fibrous Insulation (TUFI) used in protecting entry vehicles will be presented.

Leiser, Daniel B.; Rasky, Daniel J. (Technical Monitor)

1995-01-01

202

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) one more field test has been conducted in an underground coal mine, (2) optimization studies of the control parameters have been conducted, (3) the relationship among feed pressure, penetration rate and rotation rate seems to be a good indicator for estimating rock strength when both penetration rate and rotation rate are controlled or kept constant, (4) the empirical equations for eliminating the machine effect on drilling parameters were developed and verified, and (5) a real time roof geology mapping system for roof bolters in limestone mine, including a special version of the geology mapping program and hardware, performs very well in underground production condition.

Syd S. Peng

2005-04-15

203

Linking evapotranspiration to stormwater reduction and attenuation in green roofs in Calgary, Alberta  

NASA Astrophysics Data System (ADS)

Green roofs have been used for centuries to insulate buildings and beautify urban environments. European countries, especially Germany, have adopted green roofs use in modern buildings, helping raise awareness of their many potential benefits. Green roofs have been shown to: effectively reduce and filter stormwater thereby decreasing the burden on urban sewer systems; provide insulation and lower roof surface temperature leading to a decrease in building energy load and reduced sensible heat flux to the urban atmosphere; and to extend the life of a roof by decreasing the temperature fluctuations which cause roof damage. Given that green buildings can mitigate against the negative impacts of storm water runoff and reduce the heating and cooling demands, use of green roofs in Canada might prove extremely beneficial due to our intense climate. However, the implementation of green roofs in North American urban environments remains underused, in part due to a lack of climate appropriate green roof design guidelines that are supported by scientific understanding of their performance in North American climates. The capacity of a green roof installation to moderate runoff depends on the storage capacity of the rooting medium at the start of the rainfall event which in turn is constrained by roof loading. The influence of medium depth is investigated through comparison to 15 cm and 10cm deep planting modules. Storage capacity has a finite limit, making rapid drainage and evapotranspiration loss essential to restore the retardation of a subsequent storm. Sustaining live plant cover requires avoidance of saturated conditions and retention of minimum soil moisture levels. These limits constrain the design options with distinctive climatic stresses. Here the performance of experimental green roof modules is investigated under particularly high climatic stressing at Calgary Alberta Canada. 10 cm modules show rapid drying to unacceptably low residual moisture content, whereas 15cm depth appears to dry to higher moisture contents that support plant survival and growth.

Breach, P. A.; Robinson, C. E.; Voogt, J. A.; Smart, C. C.; O'Carroll, D. M.

2013-12-01

204

Thermal performance enhancement in nanofluids containing diamond nanoparticles  

NASA Astrophysics Data System (ADS)

Nanofluids, nanoparticle suspensions prepared by dispersing nanoscale particles in a base fluid, have been gaining interest lately due to their potential to greatly outperform traditional thermal transport liquids. Diamond has the highest thermal transport capacity in nature and diamond particles are often used as filler in mixtures for upgrading the performance of a matrix. It is reasonable to expect that the addition of diamond nanoparticles (DNPs) would lead to thermal performance enhancement in a base fluid. In this study, homogeneous and stable nanofluids composed of DNPs as the inclusions and a mixture of ethylene glycol (EG) and water as base fluid have been prepared. Acid mixtures of perchloric acid, nitric acid and hydrochloric acid were employed to purify and tailor the DNPs to eliminate impurities and to enhance their dispersibilty. Ultrasound and the alkalinity of solution are beneficial to the deaggregation of the soft DNP aggregations. The thermal conductivity enhancement of the DNP nanofluids increases with DNP loading and the thermal conductivity enhancement is more than 18.0% for a nanofluid at a DNP volume fraction of 0.02. Viscosity measurements show that the DNP nanofluids demonstrate Newtonian behaviour, and the viscosity significantly decreases with temperature. With increasing volume fraction of DNPs, the convective heat transfer coefficient increases first, and then decreases with a further increase in the volume fraction of DNPs. The nanofluid with a volume fraction of 0.005 has optimal overall thermal performance.

Xie, Huaqing; Yu, Wei; Li, Yang

2009-05-01

205

Thermal Performance Testing of EMU and OSS Liquid Cooling Garments  

NASA Technical Reports Server (NTRS)

A test was conducted to evaluate three factors influencing the thermal performance of liquid cooling garments (LCG): (1) the comparable thermal performance of an Oceaneering developed engineering evaluation unit (EEU) prototype LDG, (2) the effect of the thermal comfort undergarment (TCU), and (3) the performance of a torso or upper body only LCG configuration. To evaluate the thermal performance of each configuration a metabolic test was conducted, utilizing suited subjects to generate the metabolic heat. For this study three (3) test subjects of similar health and weight produced a metabolic load on the LDG configuration by either resting (300-600 BTU/hr), walking at a slow pace (1200 BRU/hr), and walking at a brisk pace (2200 BTU/hr), as outlined in Figure 1, the metabolic profile. During the test, oxygen consumption, heart rate, relative humidity, air flow, inlet and outlet air pressure, inlet and outlet air temperature, delta air temperature, water flow (100 lb/hr), inlet water temperature (64 F), delta water temperature, water pressure, core body temperature, skin temperature, and sweat loss data was recorded. Four different test configurations were tested, with one configuration tested twice, as outlined in Table 1. The test was conducted with the suit subjects wearing the Demonstrator Suit, pressurized to vent pressure (approximately 0.5 psig). The demonstrator suit has an integrated ventilation duct system and was used to create a relevant environment with a captured ventilation return, an integrated vent tree, and thermal insulation from the environment.

Rhodes, Richard; Bue, Grant; Hakam, Mary

2012-01-01

206

Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance  

NASA Technical Reports Server (NTRS)

This paper presents recent thermal model results of the Advanced Stirling Radioisotope Generator (ASRG). The three-dimensional (3D) ASRG thermal power model was built using the Thermal Desktop(trademark) thermal analyzer. The model was correlated with ASRG engineering unit test data and ASRG flight unit predictions from Lockheed Martin's (LM's) I-deas(trademark) TMG thermal model. The auxiliary cooling system (ACS) of the ASRG is also included in the ASRG thermal model. The ACS is designed to remove waste heat from the ASRG so that it can be used to heat spacecraft components. The performance of the ACS is reported under nominal conditions and during a Venus flyby scenario. The results for the nominal case are validated with data from Lockheed Martin. Transient thermal analysis results of ASRG for a Venus flyby with a representative trajectory are also presented. In addition, model results of an ASRG mounted on a Cassini-like spacecraft with a sunshade are presented to show a way to mitigate the high temperatures of a Venus flyby. It was predicted that the sunshade can lower the temperature of the ASRG alternator by 20 C for the representative Venus flyby trajectory. The 3D model also was modified to predict generator performance after a single Advanced Stirling Convertor failure. The geometry of the Microtherm HT insulation block on the outboard side was modified to match deformation and shrinkage observed during testing of a prototypic ASRG test fixture by LM. Test conditions and test data were used to correlate the model by adjusting the thermal conductivity of the deformed insulation to match the post-heat-dump steady state temperatures. Results for these conditions showed that the performance of the still-functioning inboard ACS was unaffected.

Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

2014-01-01

207

Duct thermal performance models for large commercial buildings  

SciTech Connect

Despite the potential for significant energy savings by reducing duct leakage or other thermal losses from duct systems in large commercial buildings, California Title 24 has no provisions to credit energy-efficient duct systems in these buildings. A substantial reason is the lack of readily available simulation tools to demonstrate the energy-saving benefits associated with efficient duct systems in large commercial buildings. The overall goal of the Efficient Distribution Systems (EDS) project within the PIER High Performance Commercial Building Systems Program is to bridge the gaps in current duct thermal performance modeling capabilities, and to expand our understanding of duct thermal performance in California large commercial buildings. As steps toward this goal, our strategy in the EDS project involves two parts: (1) developing a whole-building energy simulation approach for analyzing duct thermal performance in large commercial buildings, and (2) using the tool to identify the energy impacts of duct leakage in California large commercial buildings, in support of future recommendations to address duct performance in the Title 24 Energy Efficiency Standards for Nonresidential Buildings. The specific technical objectives for the EDS project were to: (1) Identify a near-term whole-building energy simulation approach that can be used in the impacts analysis task of this project (see Objective 3), with little or no modification. A secondary objective is to recommend how to proceed with long-term development of an improved compliance tool for Title 24 that addresses duct thermal performance. (2) Develop an Alternative Calculation Method (ACM) change proposal to include a new metric for thermal distribution system efficiency in the reporting requirements for the 2005 Title 24 Standards. The metric will facilitate future comparisons of different system types using a common ''yardstick''. (3) Using the selected near-term simulation approach, assess the impacts of duct system improvements in California large commercial buildings, over a range of building vintages and climates. This assessment will provide a solid foundation for future efforts that address the energy efficiency of large commercial duct systems in Title 24. This report describes our work to address Objective 1, which includes a review of past modeling efforts related to duct thermal performance, and recommends near- and long-term modeling approaches for analyzing duct thermal performance in large commercial buildings.

Wray, Craig P.

2003-10-01

208

IDENTIFYING ROOF FALL PREDICTORS USING FUZZY CLASSIFICATION  

SciTech Connect

Microseismic monitoring involves placing geophones on the rock surfaces of a mine to record seismic activity. Classification of microseismic mine data can be used to predict seismic events in a mine to mitigate mining hazards, such as roof falls, where properly bolting and bracing the roof is often an insufficient method of preventing weak roofs from destabilizing. In this study, six months of recorded acoustic waveforms from microseismic monitoring in a Pennsylvania limestone mine were analyzed using classification techniques to predict roof falls. Fuzzy classification using features selected for computational ease was applied on the mine data. Both large roof fall events could be predicted using a Roof Fall Index (RFI) metric calculated from the results of the fuzzy classification. RFI was successfully used to resolve the two significant roof fall events and predicted both events by at least 15 hours before visual signs of the roof falls were evident.

Bertoncini, C. A.; Hinders, M. K. [NDE Lab, College of William and Mary, Williamsburg, VA, 23187-8795 (United States)

2010-02-22

209

Numerical Simulations of a RoofTop Wind Turbine  

Microsoft Academic Search

Unsteady numerical simulations of a high efficiency roof-top wind turbine have been performed. The wind turbine cross section design was based on geometrical optimization study of Rahai and Hefazi for increasing contributions of the lift force to the torque, resulting in significant improvements in the performance of a vertical axis wind turbine. The wind turbine was 30 cm in diameter

Shahab Moayedian; Hamid Rahai

2010-01-01

210

B.4 ROOF SYSTEMS B.4 Roof System  

E-print Network

: clay tile, wood, shingle, metal, glass. Built-up, modified bitumen, epdm, durbigum. Fastening failure Flashing failure Blisters Expansion joints Flat Roof Physical condition Structural movement Material: Structural movement Material deterioration Leaks Clay tile, wood, shingle, metal, glass. Clean outs Pitch

Gelfond, Michael

211

Roofing Workbook and Tests: Entering the Roofing and Waterproofing Industry.  

ERIC Educational Resources Information Center

This document is one of a series of nine individual units of instruction for use in roofing apprenticeship classes in California. The unit consists of a workbook and test, perforated for student use. Fourteen topics are covered in the workbook and corresponding multiple-choice tests. For each topic, objectives, information sheets, and study…

California State Dept. of Education, Sacramento. Vocational Education Services.

212

Evaluation of Roof Bolting Requirements Based on In-Mine Roof Bolter Drilling  

Microsoft Academic Search

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to

Syd S. Peng

2005-01-01

213

Monitoring the Energy-Use Effects of Cool Roofs on California Commercial Buildings  

SciTech Connect

Solar-reflective roofs stay cooler in the sun than solar-absorptive roofs. Such ''cool'' roofs achieve lower surface temperatures that reduce heat conduction into the building and the building's cooling load. The California Energy Commission has funded research in which Lawrence Berkeley National Laboratory (LBNL) has measured the electricity use and peak demand in commercial buildings to document savings from implementing the Commission's Cool Roofs program. The study seeks to determine the savings achieved by cool roofs by monitoring the energy use of a carefully selected assortment of buildings participating in the Cool Roofs program. Measurements were needed because the peak savings resulting from the application of cool roofs on different types of buildings in the diverse California climate zones have not been well characterized to date. Only a few occupancy categories (e.g., office and retail buildings) have been monitored before this, and those were done under a limited number of climatic conditions. To help rectify this situation, LBNL was tasked to select the buildings to be monitored, measure roof performance before and after replacing a hot roof by a cool roof, and document both energy and peak demand savings resulting from installation of cool roofs. We monitored the effects of cool roofs on energy use and environmental parameters in six California buildings at three different sites: a retail store in Sacramento; an elementary school in San Marcos (near San Diego); and a 4-building cold storage facility in Reedley (near Fresno). The latter included a cold storage building, a conditioning and fruit-palletizing area, a conditioned packing area, and two unconditioned packing areas (counted as one building).

Akbari, Hashem; Levinson, Ronnen; Konopaki, Steve; Rainer, Leo

2004-07-01

214

An Integrative Analysis of an Extensive Green Roof System: A Case Study of the Schleman Green Roof  

NASA Astrophysics Data System (ADS)

In urban environments where populations continue to rise, the need for affective stormwater management and runoff control methods is ever prevalent. Increased population growth and city expansion means greater impervious surfaces and higher rates of stormwater runoff. In well-established cities, this proves particularly difficult due to a constraining built environment and limited pervious spaces, even in cities as small as 40,000 residents. Work to reduce runoff in combined sewer systems (CSS) and municipal separated storm sewer systems (MS4) by use of best-management practices is one route currently under investigation. The Purdue University campus is making efforts to reduce their impact on the West Lafayette CSS and MS4. Green roofs are one management practice being used for runoff mitigation. Specifically, Schleman Hall, an administrative student affairs building, has a small green roof located on the second floor installed in 2008. In cooperation with Purdue Physical Facilities, monitoring and analysis for the Schleman extensive green roof at Purdue University was performed from June 2012 to December 2012. The objective was to determine the stormwater retention, output water quality and net present value for the 165 m2 roof. The results from the water balance analysis revealed retention rates on average of 58% of precipitation per rain event, where retention included soil moisture, evaporation and detention/depression storage. The water quality metrics tested were Nitrate-Nitrite (NO2-NO3), Orthophosphate (PO4), Ammonia-Ammonium ion (NH3-NH4), Sulfate (SO4), total suspended solids (TSS) and pH. The pollutant concentration and load results varied, but the pH levels from precipitation increased in all samples after passing through the substrate. SO4 and PO4 results yielded higher concentrations and loads in the green roof output than the control output and precipitation, while NO2-NO3 and NH3-NH4 yielded concentrations and loads that were reduced by the green roof when compared to the control output and precipitation. The green roof caused a decrease in the energy load (KJ/hr) needed to maintain a near constant temperature in the conference room situated below the green roof. These results combined with potential carbon pricing, stormwater fees and an installment grant resulted in a net present value of $32,350 for the Schleman Hall roof. The analysis demonstrates potential benefits, but highlights the need for further research that involves a more detailed simulation and the valuing of ecosystem services offered by the green roof.

Hoover, F.; Bowling, L. C.

2013-12-01

215

Comparison of Software Models for Energy Savings from Cool Roofs  

SciTech Connect

A web-based Roof Savings Calculator (RSC) has been deployed for the United States Department of Energy as an industry-consensus tool to help building owners, manufacturers, distributors, contractors and researchers easily run complex roof and attic simulations. This tool employs modern web technologies, usability design, and national average defaults as an interface to annual simulations of hour-by-hour, whole-building performance using the world-class simulation tools DOE-2.1E and AtticSim in order to provide estimated annual energy and cost savings. In addition to cool reflective roofs, RSC simulates multiple roof and attic configurations including different roof slopes, above sheathing ventilation, radiant barriers, low-emittance roof surfaces, duct location, duct leakage rates, multiple substrate types, and insulation levels. A base case and energy-efficient alternative can be compared side-by-side to estimate monthly energy. RSC was benchmarked against field data from demonstration homes in Ft. Irwin, California; while cooling savings were similar, heating penalty varied significantly across different simulation engines. RSC results reduce cool roofing cost-effectiveness thus mitigating expected economic incentives for this countermeasure to the urban heat island effect. This paper consolidates comparison of RSC s projected energy savings to other simulation engines including DOE-2.1E, AtticSim, Micropas, and EnergyPlus, and presents preliminary analyses. RSC s algorithms for capturing radiant heat transfer and duct interaction in the attic assembly are considered major contributing factors to increased cooling savings and heating penalties. Comparison to previous simulation-based studies, analysis on the force multiplier of RSC cooling savings and heating penalties, the role of radiative heat exchange in an attic assembly, and changes made for increased accuracy of the duct model are included.

New, Joshua Ryan [ORNL; Miller, William A [ORNL; Huang, Yu (Joe) [White Box Technologies; Levinson, Ronnen [Lawrence Berkeley National Laboratory (LBNL)

2014-01-01

216

Developing resilient green roofs in a dry climate.  

PubMed

Living roofs are an emerging green infrastructure technology that can potentially be used to ameliorate both climate change and urban heat island effects. There is not much information regarding the design of green roofs for dry climates and so the aim of this study was to develop low maintenance and unfertilized green roofs for a dry climate. This paper describes the effects of four important elements of green roofs namely slope, depth, growing media and plant species and their possible interactions in terms of plant growth responses in a dry climate. Sixteen medium-scale green roofs were set up and monitored during a one year period. This experiment consisted of twelve vegetated platforms and four non-vegetated platforms as controls. The design for the experiment was a split-split-plot design in which the factors Slope (1° and 25°) and Depth (100mm, 300 mm) were randomized to the platforms (main plots). Root depth and volume, average height of plants, final dry biomass and ground cover, relative growth rate, final dry shoot-root ratio, water use efficiency and leaf succulence were studied during a twelve month period. The results showed little growth of the plants in media type A, whilst the growth was significant in both media types B and C. On average, a 90% survival rate of plants was observed. Also the growth indices indicated that some plants can grow efficiently in the harsh environment created by green roofs in a dry climate. The root growth pattern showed that retained water in the drainage layer is an alternative source of water for plants. It was also shown that stormwater can be used as a source of irrigation water for green roofs during six months of the year at the study site. In summary, mild sloping intensive systems containing media type C and planted with either Chrysocephalum apiculatum or Disphyma crassifolium showed the best performance. PMID:24880547

Razzaghmanesh, M; Beecham, S; Brien, C J

2014-08-15

217

Study of skin model and geometry effects on thermal performance of thermal protective fabrics  

NASA Astrophysics Data System (ADS)

Thermal protective clothing has steadily improved over the years as new materials and improved designs have reached the market. A significant method that has brought these improvements to the fire service is the NFPA 1971 standard on structural fire fighters’ protective clothing. However, this testing often neglects the effects of cylindrical geometry on heat transmission in flame resistant fabrics. This paper deals with methods to develop cylindrical geometry testing apparatus incorporating novel skin bioheat transfer model to test flame resistant fabrics used in firefighting. Results show that fabrics which shrink during the test can have reduced thermal protective performance compared with the qualities measured with a planar geometry tester. Results of temperature differences between skin simulant sensors of planar and cylindrical tester are also compared. This test method provides a new technique to accurately and precisely characterize the thermal performance of thermal protective fabrics.

Zhu, Fanglong; Ma, Suqin; Zhang, Weiyuan

2008-05-01

218

Demonstration of energy savings of cool roofs  

Microsoft Academic Search

Dark roofs raise the summertime air-conditioning demand of buildings. For highly-absorptive roofs, the difference between the surface and ambient air temperatures can be as high as 90 F, while for highly-reflective roofs with similar insulative properties, the difference is only about 20 F. For this reason, cool roofs are effective in reducing cooling energy use. Several experiments on individual residential

S. Konopacki; L. Gartland; H. Akbari; L. Rainer

1998-01-01

219

Portable Life Support Subsystem Thermal Hydraulic Performance Analysis  

NASA Technical Reports Server (NTRS)

This paper presents the current state of the thermal hydraulic modeling efforts being conducted for the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS). The goal of these efforts is to provide realistic simulations of the PLSS under various modes of operation. The PLSS thermal hydraulic model simulates the thermal, pressure, flow characteristics, and human thermal comfort related to the PLSS performance. This paper presents modeling approaches and assumptions as well as component model descriptions. Results from the models are presented that show PLSS operations at steady-state and transient conditions. Finally, conclusions and recommendations are offered that summarize results, identify PLSS design weaknesses uncovered during review of the analysis results, and propose areas for improvement to increase model fidelity and accuracy.

Barnes, Bruce; Pinckney, John; Conger, Bruce

2010-01-01

220

Thermal performance modeling of NASA s scientific balloons  

NASA Astrophysics Data System (ADS)

The flight performance of a scientific balloon is highly dependant on the interaction between the balloon and its environment. The balloon is a thermal vehicle. Modeling a scientific balloon's thermal performance has proven to be a difficult analytical task. Most previous thermal models have attempted these analyses by using either a bulk thermal model approach, or by simplified representations of the balloon. These approaches to date have provided reasonable, but not very accurate results. Improvements have been made in recent years using thermal analysis tools developed for the thermal modeling of spacecraft and other sophisticated heat transfer problems. These tools, which now allow for accurate modeling of highly transmissive materials, have been applied to the thermal analysis of NASA's scientific balloons. A research effort has been started that utilizes the "Thermal Desktop" addition to AUTO CAD. This paper will discuss the development of thermal models for both conventional and Ultra Long Duration super-pressure balloons. This research effort has focused on incremental analysis stages of development to assess the accuracy of the tool and the required model resolution to produce usable data. The first stage balloon thermal analyses started with simple spherical balloon models with a limited number of nodes, and expanded the number of nodes to determine required model resolution. These models were then modified to include additional details such as load tapes. The second stage analyses looked at natural shaped Zero Pressure balloons. Load tapes were then added to these shapes, again with the goal of determining the required modeling accuracy by varying the number of gores. The third stage, following the same steps as the Zero Pressure balloon efforts, was directed at modeling super-pressure pumpkin shaped balloons. The results were then used to develop analysis guidelines and an approach for modeling balloons for both simple first order estimates and detailed full models. The development of the radiative environment and program input files, the development of the modeling techniques for balloons, and the development of appropriate data output handling techniques for both the raw data and data plots will be discussed. A general guideline to match predicted balloon performance with known flight data will also be presented. One long-term goal of this effort is to develop simplified approaches and techniques to include results in performance codes being developed.

Franco, H.; Cathey, H.

221

Review of End-of-Life Thermal Control Coating Performance  

NASA Technical Reports Server (NTRS)

White thermal control coatings capable of long term performance are needed for Fission Surface Power (FSP) where heat from a nuclear reactor placed on the surface of the Moon must be rejected to the environment. The threats to thermal control coating durability on the lunar surface are electrons, protons, and ultraviolet radiation. The anticipated damage to the coating is a gradual darkening over time. The increase in solar absorptance would, in essence, add a cyclic heat load to the radiator. The greater the darkening, the greater the added heat load. The cyclic heat load could ultimately impart a cyclic influence on FSP system performance. No significant change in emittance is anticipated. Optical properties degradation data were found in the open literature for the Z-93 series of thermal control paints. Additional optical properties degradation data were found from the Lunar Orbiter V mission, the Optical Properties Monitor, and the Materials International Space Station Experiment. Anticipated end-of-life thermal control coating performance for a FSP installation is postulated. With the FSP installation located away from landing and launching areas, and out of line-of-sight, lunar dust from human activity may not be a threat. The benefits of investing in next generation thermal control paint chemistry are explored.

Jaworske, Donald A.; Kline, Sara E.

2008-01-01

222

Roof Replacement and Related Work February 17, 2000 DSR # 0000-00 XXX  

E-print Network

Roof Replacement and Related Work February 17, 2000 DSR # 0000-00 XXX SECTION 02071 - REMOVAL # 0000-00 XXX A. Removal and disposal shall be performed in accordance with ap- plicable State 02071 - 2 (Rev. 9/00) #12;Roof Replacement and Related Work February 17, 2000 DSR # 0000-00 XXX 1

223

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2010 CFR

...equivalent may be used. (3) Bearing plates used with wood or metal...materials that are used between a bearing plate and the mine roof in...shape of the roof bolt head and bearing plate. (e)(1) The...the roof bolt nor anchorage capacity of the strata....

2010-07-01

224

Roof Structure for the Amazon region  

Microsoft Academic Search

A new concept of wooden roof structure with an attached ceiling is idealized for construction in tropical climates. A scissors truss system is used for roof structure dictated by architectural considerations. The roof structure was developed using computer aided design in order to achieve an optimized construction system. This prototype project uses 3 trusses spaced 2.75m over a 5-m span,

Sá Ribeiro

225

Performance issues in solar thermal energy transport systems  

NASA Astrophysics Data System (ADS)

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.

Zimmerman, P. W.

1986-07-01

226

Solar Roof Cooling by Evaporation  

E-print Network

the under side of the roof can not only cause discomfort in a ndn air-conditioned bui1din9 but can neces sitate a lower temperature setting in an air-conditioned building to achieve a com fortable condition. Tests run at BIGELOW-SANFORD plant in Lan...

Patterson, G. V.

1981-01-01

227

Solar Roof Cooling by Evaporation  

E-print Network

the Second Industrial Energy Technology Conference Houston, TX, April 13-16, 1980 spray nozzles. but it was found that the tiny (Sprayed Roof) m Savings of 100 tons ? 1 ton serrations in the spray head. which were per 1.000 sq. ft. necessary to put a...

Patterson, G. V.

1980-01-01

228

Thermal Conduction Module: A High-Performance Multilayer Ceramic Package  

Microsoft Academic Search

Innovations in package design coupled with major advances in multilayer ceramic (MLC) technology provide a high- performance LSI package for the IBM 3081 Processor Unit. The thermal conduction module (TCM) utilizes a 90 x 90-mm MLC substrate to interconnect up to 118 LSI devices. The substrate, which typically contains 130 m of impedance-controlled wiring, provides an array of 121 pads

A. J. Blodgett; D. R. Barbour

1982-01-01

229

PERFORMANCE OF A CONCENTRATING PHOTOVOLTAIC/THERMAL SOLAR COLLECTOR  

E-print Network

PERFORMANCE OF A CONCENTRATING PHOTOVOLTAIC/THERMAL SOLAR COLLECTOR Joe S Coventry Centre Solar (CHAPS) collectors consist of glass-on- metal mirrors that focus light onto high efficiency, 1994), and in the case of air collectors, multiple pass configurations (Hegazy, 2000, Sopian et al

230

Experimental and Theoretical Investigation of Thermal Performance of Heat Sinks  

Microsoft Academic Search

Experimental and theoretical investigations of the thermal performance of a variety of heat sinks have been made. The heat sinks investigated were: extruded (or straight finned), folded (or corrugated), elliptical finned, Maxiflow (or fan tailed), small pin finned, cross-cut pin and small disk (or cylindrical). The experiments were done in a wind tunnel where the free stream velocity ranged from

Fariborz Forghan; Donald Goldthwaite; Matthew Ulinski; Hameed Metghalchi

231

Performance evaluation of solar photovoltaic\\/thermal systems  

Microsoft Academic Search

The major purpose of the present study is to understand the performance of an integrated photovoltaic and thermal solar system (IPVTS) as compared to a conventional solar water heater and to demonstrate the idea of an IPVTS design. A commercial polycrystalline PV module is used for making a PV\\/T collector. The PV\\/T collector is used to build an IPVTS. The

B. J Huang; T. H Lin; W. C Hung; F. S Sun

2001-01-01

232

Thermal performance analysis on unit tube for heat pipe receiver  

Microsoft Academic Search

To reduce the mass and improve the thermal performance of the heat receiver, a heat pipe receiver was researched for the space solar dynamic power system. Corresponding mathematical and physical models were built, and a method was devised to provide a numerical equation by which the temperature of the containment canister outer wall, heat pipe wall temperature, working fluid exit

Haiting Cui; Zhenhui Wang; Yanshu Guo; Weiqiang Xu; Xiugan Yuan

2006-01-01

233

Simulation of thermal performance of solar collector arrays  

Microsoft Academic Search

A method is described for simulating the thermal performance of solar collectors by using an in-line heat source to simulate absorbed solar energy and a nonirradiated array to simulate heat losses, during tests of solar water heating systems. The mathematical relationships needed to operate an electric heat source in series with a nonirradiated array are developed, and consideration is given

A. H. Fanney; W. C. Thomas

1981-01-01

234

Cost and performance evaluation of terrestrial solar thermal power systems  

Microsoft Academic Search

A thorough evaluation of cost and performance of solar thermal power systems is required in order to assess the viability of such systems for commercial applications, particularly before the commitment of large investments to the manufacture of particular systems. Optimization and simulation models can be effectively used for the evaluation and analysis of several varieties of these systems. A cost

El Gabalawi

1982-01-01

235

Cost and performance evaluation of terrestrial solar thermal power systems  

Microsoft Academic Search

A cost optimization model was developed based on relating systems costs to performance and minimizing the system electric energy production costs. The model was applied to systems representing major categories of solar thermal power systems such as the central receiver, the parabolic dish, the line-focusing and the fixed orientation focusing collectors. Several types of engines and energy storage systems were

N. Elgabalawi

1982-01-01

236

Performance contracting for parabolic trough solar thermal systems  

Microsoft Academic Search

Several applications of solar energy have proven viable in the energy marketplace, due to competitive technology and economic performance. One example is the parabolic trough solar collectors, which use focused solar energy to maximize efficiency and reduce material use in construction. Technical improvements are complemented by new business practices to make parabolic trough solar thermal systems technically and economically viable

H. Brown; R. Hewett; A. Walker; R. Gee; K. May

1997-01-01

237

Performance of silvered Teflon (trademark) thermal control blankets on spacecraft  

NASA Technical Reports Server (NTRS)

Silverized Teflon (Ag/FEP) is a widely used passive thermal control material for space applications. The material has a very low alpha/e ratio (less than 0.1) for low operating temperatures and is fabricated with various FEP thicknesses (as the Teflon thickness increases, the emittance increases). It is low outgassing and, because of its flexibility, can be applied around complex, curved shapes. Ag/FEP has achieved multiyear lifetimes under a variety of exposure conditions. This has been demonstrated by the Long Duration Exposure Facility (LDEF), Solar Max, Spacecraft Charging at High Altitudes (SCATHA), and other flight experiments. Ag/FEP material has been held in place on spacecraft by a variety of methods: mechanical clamping, direct adhesive bonding of tapes and sheets, and by Velcro(TM) tape adhesively bonded to back surfaces. On LDEF, for example, 5-mil blankets held by Velcro(TM) and clamping were used for thermal control over 3- by 4-ft areas on each of 17 trays. Adhesively bonded 2- and 5-mil sheets were used on other LDEF experiments, both for thermal control and as tape to hold other thermal control blankets in place. Performance data over extended time periods are available from a number of flights. The observed effects on optical properties, mechanical properties, and surface chemistry will be summarized in this paper. This leads to a discussion of performance life estimates and other design lessons for Ag/FEP thermal control material.

Pippin, Gary; Stuckey, Wayne; Hemminger, Carol

1993-01-01

238

Life-cycle cost-benefit analysis of extensive vegetated roof systems.  

PubMed

The built environment has been a significant cause of environmental degradation in the previously undeveloped landscape. As public and private interest in restoring the environmental integrity of urban areas continues to increase, new construction practices are being developed that explicitly value beneficial environmental characteristics. The use of vegetation on a rooftop--commonly called a green roof--as an alternative to traditional roofing materials is an increasingly utilized example of such practices. The vegetation and growing media perform a number of functions that improve environmental performance, including: absorption of rainfall, reduction of roof temperatures, improvement in ambient air quality, and provision of urban habitat. A better accounting of the green roof's total costs and benefits to society and to the private sector will aid in the design of policy instruments and educational materials that affect individual decisions about green roof construction. This study uses data collected from an experimental green roof plot to develop a benefit cost analysis (BCA) for the life cycle of extensive (thin layer) green roof systems in an urban watershed. The results from this analysis are compared with a traditional roofing scenario. The net present value (NPV) of this type of green roof currently ranges from 10% to 14% more expensive than its conventional counterpart. A reduction of 20% in green roof construction cost would make the social NPV of the practice less than traditional roof NPV. Considering the positive social benefits and relatively novel nature of the practice, incentives encouraging the use of this practice in highly urbanized watersheds are strongly recommended. PMID:17368704

Carter, Timothy; Keeler, Andrew

2008-05-01

239

A Roof for ALMA  

NASA Astrophysics Data System (ADS)

On 10 March, an official ceremony took place on the 2,900m high site of the Atacama Large Millimeter/submillimeter Array (ALMA) Operations Support Facility, from where the ALMA antennas will be remotely controlled. The ceremony marked the completion of the structural works, while the building itself will be finished by the end of the year. This will become the operational centre of one of the most important ground-based astronomical facilities on Earth. ESO PR Photo 13a/07 ESO PR Photo 13a/07 Cutting the Red Ribbon The ceremony, known as 'Tijerales' in Chile, is the equivalent to the 'roof-topping ceremony' that takes place worldwide, in one form or another, to celebrate reaching the highest level of a construction. It this case, the construction is the unique ALMA Operations Support Facility (OSF), located near the town of San Pedro de Atacama. "The end of this first stage represents an historic moment for ALMA," said Hans Rykaczewski, the European ALMA Project Manager. "Once completed in December 2007, this monumental building of 7,000 square metres will be one of the largest and most important astronomical operation centres in the world." ALMA, located at an elevation of 5,000m in the Atacama Desert of northern Chile, will provide astronomers with the world's most advanced tool for exploring the Universe at millimetre and submillimetre wavelengths. ALMA will detect fainter objects and be able to produce much higher-quality images at these wavelengths than any previous telescope system. The OSF buildings are designed to suit the requirements of this exceptional observatory in a remote, desert location. The facility, which will host about 100 people during operations, consists of three main buildings: the technical building, hosting the control centre of the observatory, the antenna assembly building, including four antenna foundations for testing and maintenance purposes, and the warehouse building, including mechanical workshops. Further secondary buildings are the transporter shelters and the vehicle maintenance facilities as well as the ALMA gate house. The construction started in August 2006 and will be completed in December 2007. ESO PR Photo 13b/07 ESO PR Photo 13b/07 The Ceremony The ceremony took place in the presence of representatives of the regional authorities, members of the Chilean Parliament, and representatives of the local community, including the mayor of San Pedro, Ms. Sandra Berna, who joined more than 40 representatives of ESO, NRAO and NAOJ - the organisations that are, together, building ALMA. "This is certainly a big step in the realisation of the ALMA Project. The completion of this facility will be essential for assembly, testing and adjustment as well as operation and maintenance of all ALMA antennas from Europe, North America and from Japan," said Ryusuke Ogasawara, the representative of NAOJ in Chile. "This is a tremendous achievement and represents a major milestone for the ALMA project," said Adrian Russell, North American Project Manager for ALMA. ESO PR Photo 13c/07 ESO PR Photo 13c/07 The OSF (Artist's View) The first ALMA antennas, the prototypes of which successfully achieved their first combined astronomical observation last week, are expected to arrive at the ALMA site in a few months. These huge antennas will travel in pieces from Europe, USA and Japan and will be assembled next to the OSF building. The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership among Europe, Japan and North America, in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organisation for Astronomical Research in the Southern Hemisphere, in Japan by the National Institutes of Natural Sciences (NINS) in cooperation with the Academia Sinica in Taiwan and in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC). ALMA construction and operations are led on behalf of Europe by ESO, on behalf of Japan by the National As

2007-03-01

240

Design and performance of Skylab thermal/environmental control system  

NASA Technical Reports Server (NTRS)

The function of the thermal/environmental control systems was to provide a comfortable thermal environment for the crew, to cool electronic components, to supply a controlled oxygen/nitrogen atmosphere, and to remove moisture, carbon dioxide, odors, and trace contaminants from the atmosphere. A separate refrigeration system was used to chill and freeze food and biomedical samples and to provide cold water for drinking. This paper describes system design and compares in-flight performance to preflight predictions. A discussion of in-flight anomalies and corrective actions is also included.

Hopson, G. D.; Littles, J. W.; Patterson, W. C.

1974-01-01

241

Density dependence of reactor performance with thermal confinement scalings  

SciTech Connect

Energy confinement scalings for the thermal component of the plasma published thus far have a different dependence on plasma density and input power than do scalings for the total plasma energy. With such thermal scalings, reactor performance (measured by Q, the ratio of the fusion power to the sum of the ohmic and auxiliary input powers) worsens with increasing density. This dependence is the opposite of that found using scalings based on the total plasma energy, indicating that reactor operation concepts may need to be altered if this density dependence is confirmed in future research.

Stotler, D.P.

1992-03-01

242

Thermal performance of a geofluid direct-contact heat exchanger  

SciTech Connect

A sieve-tray direct-contact heat exchanger was used to transfer heat from a 280/sup 0/F geothermal fluid to the working fluid, isobutane, in the Raft River 60kW prototype plant. A series of experiments were run at different working fluid-to-geofluid flow ratios which produced different boiling conditions. In this paper, the results of these experiments are analyzed on the basis of thermal performance. The flow ratio, the geofluid outlet temperature, the working fluid inlet temperature, the amount of working fluid dissolved or entrained in geofluid, and tray efficiency are varied and preheating temperature profiles are calculated. These are compared with the experimentally obtained temperature profiles and the relative effects of the variables are evaluated. From this, it was determined that the approach temperature difference was on the order of .1/sup 0/ after 17 preheating trays, and the tray efficiencies, which appear to be about the same for all trays, reached approx. 70%. It was also determined that entrainment has a negligible effect on column thermal performance. The thermal performance of this column compares favorably with a spray-tower direct-contact heat exchanger and a shell-and-tube heat exchanger in terms of overall heat-transfer coefficient. Distributor tray and boiling tray behavior are discussed. These is some discussion of operations and thermal hydraulics as well.

Wiggins, D.J.; Mines, G.L.; Wahl, E.

1983-01-01

243

Performance penalties caused by thermal coupling in solar piping loops  

SciTech Connect

Solar heating systems often employ conduits to carry cool fluid to the collector array and to carry the heated fluid back to the storage tank. In systems in which these two conduits are bundled together in one cover (in what has come to be known as the `life-line`) there is a thermal performance penalty caused by heat transfer from the hot conduit to the cold conduit. This cross heat transfer results in a penalty in system performance, and this paper is about evaluating this penalty. We show that the standard Hottel-Whillier-Bliss (HWB) equation can be modified to simultaneously take into account both the pipe heat losses to the ambient environment and the cross heat transfer between the hot and cold streams. Parameters in these equations are the thermal resistances between the fluids and between each fluid and the ambient. Methods are presented for both calculating and measuring these thermal resistances. We carry out sample calculations of the parameters in the modified HWB equation for a representative solar DHW system equipped with either of two different life-lines of commercial design. System simulations using these parameters reveal that the thermal effects of these life-lines are to reduce the net delivered solar energy by 6-14%, and that heat loss to ambient is more detrimental to the system performance than heat transfer from the hot to the cold conduit. 8 refs., 4 figs., 2 tabs.

Brunger, A.P.; Hollands, K.G.T.; Anthony, M.A.; Zielonko, D.; Liang, C. [Univ. of Waterloo (Canada)] [Univ. of Waterloo (Canada)

1996-10-01

244

Computational Analysis on Performance of Thermal Energy Storage (TES) Diffuser  

NASA Astrophysics Data System (ADS)

Application of thermal energy storage (TES) system reduces cost and energy consumption. The performance of the overall operation is affected by diffuser design. In this study, computational analysis is used to determine the thermocline thickness. Three dimensional simulations with different tank height-to-diameter ratio (HD), diffuser opening and the effect of difference number of diffuser holes are investigated. Medium HD tanks simulations with double ring octagonal diffuser show good thermocline behavior and clear distinction between warm and cold water. The result show, the best performance of thermocline thickness during 50% time charging occur in medium tank with height-to-diameter ratio of 4.0 and double ring octagonal diffuser with 48 holes (9mm opening ~ 60%) acceptable compared to diffuser with 6mm ~ 40% and 12mm ~ 80% opening. The conclusion is computational analysis method are very useful in the study on performance of thermal energy storage (TES).

Adib, M. A. H. M.; Adnan, F.; Ismail, A. R.; Kardigama, K.; Salaam, H. A.; Ahmad, Z.; Johari, N. H.; Anuar, Z.; Azmi, N. S. N.

2012-09-01

245

Predictive Service Life Tests for Roofing Membranes  

NASA Astrophysics Data System (ADS)

The average service life of roofing membranes used in low-slope applications on U.S. Army buildings is estimated to be considerably shorter than the industry-presumed 20-year design life, even when installers carefully adhere to the latest guide specifications. This problem is due in large part to market-driven product development cycles, which do not include time for long-term field testing. To reduce delivery costs, contractors may provide untested, interior membranes in place of ones proven satisfactory in long-term service. Federal procurement regulations require that roofing systems and components be selected according to desired properties and generic type, not brand name. The problem is that a material certified to have satisfactory properties at installation time will not necessarily retain those properties in service. The overall objective of this research is to develop a testing program that can be executed in a matter of weeks to adequately predict a membrane's long-term performance in service. This report details accelerated aging tests of 12 popular membrane materials in the laboratory, and describes outdoor experiment stations set up for long-term exposure tests of those same membranes. The laboratory results will later be correlated with the outdoor test results to develop performance models and predictive service life tests.

Bailey, David M.; Cash, Carl G.; Davies, Arthur G.

2002-09-01

246

Impact of different backgrounds on thermal infrared IDS performance  

SciTech Connect

The performance of a passive thermal infrared IDS (intrusion detection system) employed in an exterior security application can be significantly impacted by the synergistic effects of the local background and weather. As reported by Peck, these effects can lead to nuisance alarms resulting from radiance fluctuations in the background. They can also lead to missed intrusion detections due to inadequate thermal contrasts between the intruder and background. It is important to identify and to quantify the environmental scenarios which pose such risks to an infrared IDS. This paper describes, through the use of a model presented at last year`s INMM annual meeting and a recently developed intruder thermal model, how several different background types affect the ability of a specific passive infrared IDS to detect intruders. The issues discussed and problems identified apply to passive infrared IDSs in general, and not just to the specific system examined.

Lacombe, J. [Army Cold Regions Research and Engineering Lab., Hanover, NH (United States)

1993-12-31

247

Parametric study of solar thermal rocket nozzle performance  

SciTech Connect

Continued exploration and exploitation of space will require the development of more efficient and economical systems for access to and transportation through space. Solar thermal propulsion has emerged as a potential candidate to fill this role. A solar thermal rocket using hydrogen (H{sub 2}) propellant has a theoretical I{sub sp} of 700--1,100 seconds based on typical temperatures in the absorber/heat exchanger of 3,500--6,500 {degree}R (1,944--3,611 K). This note describes the significant results of a fundamental study of the potential causes of I{sub sp} reduction in low thrust, solar thermal rocket nozzles. The main emphasis is an analytical/numerical study of how nozzle geometry impacts the viscous and thermochemical losses. The results are applicable to optimizing nozzle geometry for maximum performance.

Pearson, J.B. [National Aeronautics and Space Administration, Huntsville, AL (United States). Marshall Space Flight Center; Landrum, D.B.; Hawk, C.W. [Univ. of Alabama, Huntsville, AL (United States). Propulsion Research Center

1996-08-01

248

The performance check between whole building thermal performance criteria and exterior wall measured clear wall R-value, thermal bridging, thermal mass, and airtightness  

SciTech Connect

At the last IEA Annex 32 meeting it was proposed that the annex develop the links between level 1 (the whole building performance) and level 2 (the envelope system). This paper provides a case study of just that type of connection. An exterior wall mockup is hot box tested and modeled in the laboratory. Measurements of the steady state and dynamic behavior of this mockup are used as the basis to define the thermal bridging, thermal mass benefit and air tightness of the whole wall system. These level two performance characteristics are related to the whole building performance. They can be analyzed by a finite difference modeling of the wall assembly. An equivalent wall theory is used to convert three dimensional heat flow to one dimensional terms that capture thermal mass effects, which in turn are used in a common whole building simulation model. This paper illustrates a performance check between the thermal performance of a Massive ICF (Insulating Concrete Form) wall system mocked up (level 2) and Whole Building Performance criteria (level 1) such as total space heating and cooling loads (thermal comfort).

Kosny, J.; Christian, J.E.; Desjarlais, A.O. [Oak Ridge National Lab., TN (United States). Buildings Technology Center; Kossecka, E. [Polish Academy of Sciences (Poland); Berrenberg, L. [American Polysteel Forms (United States)

1998-06-01

249

EVALUATION OF VOC EMISSIONS FROM HEATED ROOFING ASPHALT  

EPA Science Inventory

The report gives results of a short-term in-house project to characterize emissions from a simulated asphalt roofing kettle, performed at EPA/AEERL. ot asphalt surfacing and resurfacing has been identified as a possible significant source of volatile organic compound (VOC) emissi...

250

Green Roof Research through EPA's Regional Applied Research Effort - slides  

EPA Science Inventory

The U.S. Environmental Protection Agency?s (EPA) Regional Applied Research Effort (RARE) allows the Regions of the EPA to choose research projects to be performed in partnership with EPA?s Office of Research and Development (ORD). Over the last decade, several green roof projects...

251

Heat flux through a Trombe wall\\/roof  

Microsoft Academic Search

This paper presents an analysis of the behaviour of a Trombe wall\\/roof consisting of pipes, laid in a solid block, one surface of which is exposed to the sun, the other surface being in direct contact with a room maintained at a constant temperature, [theta]R. Numerical calculations were performed for the relevant parameters of the system, corresponding to the solar

Sant Ram; H. P. Garg

1985-01-01

252

Thermal performance of a customized multilayer insulation (MLI)  

NASA Technical Reports Server (NTRS)

The thermal performance of a LH2 tank on a shroudless vehicle was investigated. The 1.52 m (60 in) tank was insulated with 2 MLI blankets consisting of 18 double aluminized Mylar radiation shields and 19 silk net spacers. The temperature of outer space was simulated by using a cryoshroud which was maintained at near liquid hydrogen temperature. The heating effects of a payload were simulated by utilizing a thermal payload simulator (TPS) viewing the tank. The test program consisted of three major test categories: (1) null testing, (2) thermal performance testing of the tank installed MLI system, and (3) thermal testing of a customized MLI configuration. TPS surface temperatures during the null test were maintained at near hydrogen temperature and during test categories 2 and 3 at 289 K (520R). The heat flow rate through the tank installed MLI at a tank/TPS spacing of 0.457 m was 1.204 watts with no MLI on the TPS and 0.059 watts through the customized MLI with three blankets on the TPS. Reducing the tank/TPS spacing from 0.457 m to 0.152 m the heat flow through the customized MLI increased by 10 percent.

Leonhard, K. E.

1976-01-01

253

Hybrid Model of Existing Buildings for Transient Thermal Performance Estimation  

E-print Network

-2 model prediction and measurement. Searching the best values of the 2R2C model parameters is a typical 2C 1C )2, tim )1, tim 2R 1R 1Q2,rwin rfQ )out winR laQ frQ convQ inC )in actQ i: the number of walls at different orientations rf: roof t...: time e: exterior wall in: indoor air im: internal mass r: radiative heat conv: convective fr: fresh air la: latent heat gain act: actual cooling load win: window sol: solar air out: outside 2R2C of Internal mass Detailed model of roof...

Xu, X.; Wang, S.

2006-01-01

254

Assessment and Prediction of the Thermal Performance of a Centralized Latent Heat Thermal Energy Storage Utilizing Artificial Neural Network  

E-print Network

A simulation tool is developed to analyze the thermal performance of a centralized latent heat thermal energy storage system (LHTES) using computational fluid dynamics (CFD). The LHTES system is integrated with a mechanical ventilation system...

El-Sawi, A.; Haghighat, F.; Akbari, H.

2013-01-01

255

Background character research for synthetical performance of thermal imaging systems  

NASA Astrophysics Data System (ADS)

Background is assumed to be uniform usually for evaluating the performance of thermal imaging systems, however the impact of background cannot be ignored for target acquisition in reality, background character is important research content for thermal imaging technology. A background noise parameter 𝜎 was proposed in MRTD model and used to describe background character. Background experiments were designed, and some typical backgrounds (namely lawn background, concrete pavement background, trees background and snow background) character were analyzed by 𝜎. MRTD including 𝜎 was introduced into MRTD-Channel Width (CW) model, the impact of above typical backgrounds for target information quantity were analyzed by MRTD-CW model with background character. Target information quantity for different backgrounds was calculated by MRTD-CW, and compared with that of TTP model. A target acquisition performance model based on MRTD-CW with background character will be research in the future.

Chen, Song-lin; Wang, Ji-hui; Wang, Xiao-wei; Jin, Wei-qi

2014-05-01

256

The effect of DEB powder processing on thermal cell performance  

NASA Astrophysics Data System (ADS)

During the last twenty years, the system Ca/LiCl-KCl-CaCrO4/Fe has provided the basis for thermal batteries designed for military applications. In connection with greater performance demands, investigations are being conducted concerning the effect of catholyte processing on thermal cell performance. The catholyte layer is composed of three components including the depolarizer (D), CaCrO4, the electrolyte (E), LiCl-KCl eutectic, and the binder (B), finely divided SiO2. The catholyte layer or DEB pellets are produced by blending these components, fusing, pulverizing the cake, and hydrostatically pressing the powder into pellets. A description is given of ten powders which were prepared for the reported study. It was found that the procedure used in powder processing affects the capacity, but not its voltage. Increasing the prebake temperature for CaCrO4 from 400 to 600 C resulted in an increase in capacity.

Szwarc, R.; Walton, R. D.

257

ENERGY PERFORMANCE OF BOREHOLE THERMAL ENERGY STORAGE SYSTEMS  

Microsoft Academic Search

This paper describes the energy performance of an underground thermal energy storage system that consists of high efficiency heat pump and Borehole- Heat-Exchangers (BHE). The energy conservation concept of this system is operation of the heat pump at higher efficiency using the Water-Source-Heat- Pump (WSHP). For this concept, the seasonal storage system using BHE under the ground is adopted as

Hiroshi Ohga; Kenji Mikoda; Rio de Janeiro

258

Thermal performance evaluation of the infrared telescope dewar subsystem  

NASA Technical Reports Server (NTRS)

Thermal performance evaluations (TPE) were conducted with the superfluid helium dewar of the Infrared Telescope (IRT) experiment from November 1981 to August 1982. Test included measuring key operating parameters, simulating operations with an attached instrument cryostat and validating servicing, operating and safety procedures. Test activities and results are summarized. All objectives are satisfied except for those involving transfer of low pressure liquid helium (LHe) from a supply dewar into the dewar subsystem.

Urban, E. W.

1986-01-01

259

Thermal performances of different types of underground heat exchangers  

Microsoft Academic Search

An experiment system with different types of U-vertical ground coupled heat exchanger (UGCHE) in situ was set up, for example, single or double U-pipes with sandstone backfills, and single U-pipe with cement backfills. Experiments on the thermal performance of UGCHE were carried out in different conditions, such as different inlet temperature, flow rate, soil types, backfill materials, number of U-pipes

Xinguo Li; Yan Chen; Zhihao Chen; Jun Zhao

2006-01-01

260

Dermal exposure and urinary 1-hydroxypyrene among asphalt roofing workers  

SciTech Connect

The primary objective of this study was to identify significant determinants of dermal exposure to polycyclic aromatic compounds (PACs) among asphalt roofing workers and use urinary 1-hydroxyprene (1-OHP) measurements to evaluate the effect of dermal exposure on total absorbed dose. The study population included 26 asphalt roofing workers who performed three primary tasks: tearing off old roofs, putting down new roofs, and operating the kettle at ground level. During multiple consecutive work shifts, dermal patch samples were collected from the underside of each worker's wrists and were analyzed for PACs, pyrene, and benzo(a)pyrene (BAP). During the same work week, urine samples were collected at pre-shift, post-shift, and bedtime each day and were analyzed for 1-OHP (205 urine samples). Linear mixed effects models were used to evaluate the dermal measurements for the purpose of identifying important determinants of exposure, and to evaluate urinary 1-OHP measurements for the purpose of identifying important determinants of total absorbed dose. Dermal exposures to PAC, pyrene, and BAP were found to vary significantly by roofing task and by the presence of an old coal tar pitch roof. For each of the three analytes, the adjusted mean dermal exposures associated with tear-off were approximately four times higher than exposures associated with operating the kettle. Exposure to coal tar pitch was associated with a 6-fold increase in PAC exposure, an 8-fold increase in pyrene exposure and a 35-fold increase in BAP exposure. The presence of coal tar pitch was the primary determinant of dermal exposure, particularly for exposure to BAP. However, the task-based differences that were observed while controlling for pitch suggest that exposure to asphalt also contributes to dermal exposures.

McClean, M.D.; Rinehart, R.D.; Sapkota, A.; Cavallari, J.M.; Herrick, R.F. [Boston University School of Public Health, Boston, MA (United States)

2007-07-01

261

Thermal and other tests of photovoltaic modules performed in natural sunlight  

NASA Technical Reports Server (NTRS)

The bulk of the testing was the characterization of twenty-nine modules according to their nominal operating cell temperature (NOCT) and the effect on NOCT of changes in module design, various residential roof mounting configurations, and dirt accumulation. Other tests, often performed parallel with the NOCT measurements, evaluated the improvement in electrical performance by cooling the modules with water and by channeling the waste heat into a phase change material (wax). Electrical degradation resulting from the natural marriage of photovoltaic and solar water heating modules was also demonstrated. Cost effectiveness of each of these techniques are evaluated in light of the LSA cost goal of $0.50 per watt.

Stultz, J. W.

1978-01-01

262

Lithium-ion capacitors: Electrochemical performance and thermal behavior  

NASA Astrophysics Data System (ADS)

We report on the electrochemical performance of 500 F, 1100 F, and 2200 F lithium-ion capacitors containing carbonate-based electrolytes. First and second generation lithium-ion capacitors were cycled at temperatures ranging from -30 °C to 65 °C, with rates from 5 C to 200 C. Unlike acetonitrile-based electric double-layer capacitors, whose performance has been reported to be relatively insensitive to temperatures between -30 °C and 40 °C, lithium-ion capacitor performance degrades at low temperatures and displays characteristics typical of a lithium-ion battery. Three-electrode lithium-ion capacitor cycling tests revealed that reduced capacity at low temperatures is due to the polarization of the lithiated, negative electrode. The self-discharge of cells at the various temperatures was studied and compared to an electric double-layer capacitor and a lithium-ion battery cell. Lithium-ion capacitors and batteries were observed to have significantly lower self-discharge rates than electric double-layer capacitors. Accelerating rate calorimetry and differential scanning calorimetry were used to assess the thermal runaway behavior of full cells along with the thermal properties of the cell components. Our study showed that the thermal behavior of the lithium-ion capacitor is in between those of an electric double-layer capacitor and a lithium-ion battery.

Smith, Patricia H.; Tran, Thanh N.; Jiang, Thomas L.; Chung, Jaesik

2013-12-01

263

Life sciences passive GN2 freezer thermal performance test  

NASA Technical Reports Server (NTRS)

Thermal performance tests that were conducted on the life sciences passive GN2 freezer project are summarized as well as the improvements to the freezers to improve the thermal performance of the containers. Procedures were developed, based upon these tests, to initially charge the freezers with LN2 and verify that the freezer performance is adequate for the mission duration. Improvements were made to the corvac sample tube to limit the amount of breakage due to thermal expansion of the liquid during freezing. A method of verifying the freezer vacuum insulative integrity was defined as well as a procedure for refurbishment of the internal vacuum level. Freezer modifications were made to ease the reevacuation of the containers. The orientation of the freezer in a 1-G environment, after being charged, had to remain in a vertical position. The LN2 boiloff rate increased significantly in a horizontal position. This resulted in a stowage definition in the spacecraft prior to launch. Functional testing, using the SL-1 mission timeline showed that the freezer will maintain samples in the frozen state for the duration of the mission.

Belshaw, G. W.

1981-01-01

264

Analysis of thermal performance of penetrated multi-layer insulation  

NASA Technical Reports Server (NTRS)

Results of research performed for the purpose of studying the sensitivity of multi-layer insulation blanket performance caused by penetrations through the blanket are presented. The work described in this paper presents the experimental data obtained from thermal vacuum tests of various penetration geometries similar to those present on the Hubble Space Telescope. The data obtained from these tests is presented in terms of electrical power required sensitivity factors referenced to a multi-layer blanket without a penetration. The results of these experiments indicate that a significant increase in electrical power is required to overcome the radiation heat losses in the vicinity of the penetrations.

Foster, Winfred A., Jr.; Jenkins, Rhonald M.; Yoo, Chai H.; Barrett, William E.

1988-01-01

265

Military applications for high-performance thermal imaging  

NASA Astrophysics Data System (ADS)

The recent developments in high-performance infrared sensor technology are opening up new opportunities for exploitation in the defence and security domains. In this paper, the focal plane array developments in the UK on low noise techniques, avalanche photodiodes, high operating temperature devices and large format cameras are reviewed and impact upon military capability is discussed. These technological developments are focused towards enduring challenges including the stand-off identification of hazardous materials and long range target recognition and are enabling exploitation of high performance thermal imaging onto a wide range of smaller platforms.

McEwan, Ken

2015-01-01

266

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. In this quarter, retrofitting work to build a dedicated roof bolter for this research has been started. A number of numerical methods have been developed to improve the quality of and to analyze the collected drilling parameters. Finite element modeling of roof bolting mechanism is continuing.

Syd S. Peng

2001-07-15

267

Materials performance in prototype Thermal Cycling Absorption Process (TCAP) columns  

SciTech Connect

Two prototype Thermal Cycling Absorption Process (TCAP) columns have been metallurgically examined after retirement, to determine the causes of failure and to evaluate the performance of the column container materials in this application. Leaking of the fluid heating and cooling subsystems caused retirement of both TCAP columns, not leaking of the main hydrogen-containing column. The aluminum block design TCAP column (ABL block TCAP) used in the Advanced Hydride Laboratory, Building 773-A, failed in one nitrogen inlet tube that was crimped during fabrication, which lead to fatigue crack growth in the tube and subsequent leaking of nitrogen from this tube. The Third Generation stainless steel design TCAP column (Third generation TCAP), operated in 773-A room C-061, failed in a braze joint between the freon heating and cooling tubes (made of copper) and the main stainless steel column. In both cases, stresses from thermal cycling and local constraint likely caused the nucleation and growth of fatigue cracks. No materials compatibility problems between palladium coated kieselguhr (the material contained in the TCAP column) and either aluminum or stainless steel column materials were observed. The aluminum-stainless steel transition junction appeared to be unaffected by service in the AHL block TCAP. Also, no evidence of cracking was observed in the AHL block TCAP in a location expected to experience the highest thermal shock fatigue in this design. It is important to limit thermal stresses caused by constraint in hydride systems designed to work by temperature variation, such as hydride storage beds and TCAP columns.

Clark, E.A.

1992-11-21

268

Materials performance in prototype Thermal Cycling Absorption Process (TCAP) columns  

SciTech Connect

Two prototype Thermal Cycling Absorption Process (TCAP) columns have been metallurgically examined after retirement, to determine the causes of failure and to evaluate the performance of the column container materials in this application. Leaking of the fluid heating and cooling subsystems caused retirement of both TCAP columns, not leaking of the main hydrogen-containing column. The aluminum block design TCAP column (AHL block TCAP) used in the Advanced Hydride Laboratory, Building 773-A, failed in one nitrogen inlet tube that was crimped during fabrication, which lead to fatigue crack growth in the tube and subsequent leaking of nitrogen from this tube. The Third Generation stainless steel design TCAP column (Third generation TCAP), operated in 773-A room C-061, failed in a braze joint between the freon heating and cooling tubes (made of copper) and the main stainless steel column. In both cases, stresses from thermal cycling and local constraint likely caused the nucleation and growth of fatigue cracks. No materials compatibility problems between palladium coated kieselguhr (the material contained in the TCAP column) and either aluminum or stainless steel column materials were observed. The aluminum-stainless steel transition junction appeared to be unaffected by service in the AHL block TCAP. Also, no evidence of cracking was observed in the AHL block TCAP in a location expected to experience the highest thermal shock fatigue in this design. It is important to limit thermal stresses caused by constraint in hydride systems designed to work by temperature variation, such as hydride storage beds and TCAP columns.

Clark, E.A.

1992-11-21

269

ASME PTC 47 - IGCC performance testing: Gasification island thermal performance testing  

SciTech Connect

In the past several years, Integrated Gasification Combined Cycle (IGCC) power plants have been introduced in a number of competitive markets. Most of the demonstration projects have been subsidized. However, as the technology is further developed, its versatility will lead to its application in a variety of market segments. This leads to the need of the user to evaluate the performance of the gasification process within the IGCC power plant through field testing. This paper deals with an approach to measuring the gasification island thermal performance. A thermal efficiency term based upon an input/output test approach is introduced. Measured parameters and pre-test planning are discussed. Computational procedures for determining the thermal efficiency of the gasification island are described including an uncertainty analysis for the performance test.

Mirolli, M.D.; Doering, E.L.

1998-07-01

270

The Trade-off between Solar Reflectance and Above-Sheathing Ventilation for Metal Roofs on Residential and Commercial Buildings  

SciTech Connect

An alternative to white and cool-color roofs that meets prescriptive requirements for steep-slope (residential and non-residential) and low-slope (non-residential) roofing has been documented. Roofs fitted with an inclined air space above the sheathing (herein termed above-sheathing ventilation, or ASV), performed as well as if not better than high-reflectance, high-emittance roofs fastened directly to the deck. Field measurements demonstrated the benefit of roofs designed with ASV. A computer tool was benchmarked against the field data. Testing and benchmarks were conducted at roofs inclined at 18.34 ; the roof span from soffit to ridge was 18.7 ft (5.7 m). The tool was then exercised to compute the solar reflectance needed by a roof equipped with ASV to exhibit the same annual cooling load as that for a direct-to-deck cool-color roof. A painted metal roof with an air space height of 0.75 in. (0.019 m) and spanning 18.7 ft (5.7 m) up the roof incline of 18.34 needed only a 0.10 solar reflectance to exhibit the same annual cooling load as a direct-to-deck cool-color metal roof (solar reflectance of 0.25). This held for all eight ASHRAE climate zones complying with ASHRAE 90.1 (2007a). A dark heat-absorbing roof fitted with 1.5 in. (0.038 m) air space spanning 18.7 ft (5.7 m) and inclined at 18.34 was shown to have a seasonal cooling load equivalent to that of a conventional direct-to-deck cool-color metal roof. Computations for retrofit application based on ASHRAE 90.1 (1980) showed that ASV air spaces of either 0.75 or 1.5 in. (0.019 and 0.038 m) would permit black roofs to have annual cooling loads equivalent to the direct-to-deck cool roof. Results are encouraging, and a parametric study of roof slope and ASV aspect ratio is needed for developing guidelines applicable to all steep- and low-slope roof applications.

Desjarlais, Andre Omer [ORNL] [ORNL; Kriner, Scott [Metal Construction Association, Glenview, IL] [Metal Construction Association, Glenview, IL; Miller, William A [ORNL] [ORNL

2013-01-01

271

Thermoacoustic power effect on the refrigeration performance of thermal separators  

NASA Astrophysics Data System (ADS)

An experimental investigation on the refrigeration processes occurring in a receiving tube of a thermal separator was conducted in order to determine the primary factors affecting the refrigeration performance of this new type of refrigerator. In the current investigation, the gas in the system is divided into the oscillating gas and driving gas. While the compression/expansion of the oscillating gas caused by the driving gas determines the refrigeration process occurring in the receiving tube of the thermal separator, the temperature gradient on the receiving tube significantly affects the acoustic power generation and refrigeration performance. Experimental results demonstrate that when the tube-wall temperature difference near the open end of the receiving tube increases, the refrigeration coefficient increases. Using the information presented in the paper, a new cryogenic refrigeration system was developed, and the experimental data shows that the temperature of the cryogenic air flow in the system could reach -130 °C within 50 min. It suggests that the thermal separator investigated in the paper can be employed in the field of cryogenic engineering.

Liang, S. B.; Li, X. L.; Ma, H. B.

2003-09-01

272

Thermal Performance Testing of Order Dependancy of Aerogels Multilayered Insulation  

NASA Technical Reports Server (NTRS)

Robust multilayer insulation systems have long been a goal of many research projects. Such insulation systems must provide some degree of structural support and also mechanical integrity during loss of vacuum scenarios while continuing to provide insulative value to the vessel. Aerogel composite blankets can be the best insulation materials in ambient pressure environments; in high vacuum, the thermal performance of aerogel improves by about one order of magnitude. Standard multilayer insulation (MU) is typically 50% worse at ambient pressure and at soft vacuum, but as much as two or three orders of magnitude better at high vacuum. Different combinations of aerogel and multilayer insulation systems have been tested at Cryogenics Test Laboratory of NASA Kennedy Space Center. Analysis performed at Oak Ridge National Laboratory showed an importance to the relative location of the MU and aerogel blankets. Apparent thermal conductivity testing under cryogenic-vacuum conditions was performed to verify the analytical conclusion. Tests results are shown to be in agreement with the analysis which indicated that the best performance is obtained with aerogel layers located in the middle of the blanket insulation system.

Johnson, Wesley L.; Fesmire, James E.; Demko, J. A.

2009-01-01

273

Indoor thermal performance evaluation of Daystar solar collector  

NASA Technical Reports Server (NTRS)

The test procedures used and results obtained from a test program to obtain thermal performance data on a Daystar Model 21B, S/N 02210, Unit 2, liquid solar collector under simulated conditions are described. The test article is a flat plate solar collector using liquid as a heat transfer medium. The absorber plate is copper and coated with black paint. Between the tempered low iron glass and absorber plate is a polycarbonate trap used to suppress convective heat loss. The collector incorporates a convector heat dump panel to limit temperature excursions during stagnation. The following tests were conducted: (1) collector thermal efficiency; (2) collector time constant; (3) collector incident angle modifier; (4) collector heat loss coefficient; and (5) collector stagnation.

Shih, K., Sr.

1977-01-01

274

Ballistic Performance of Porous-Ceramic, Thermal-Protection-Systems  

NASA Technical Reports Server (NTRS)

Porous-ceramic, thermal protection systems are used heavily in current reentry vehicles like the Space Shuttle and are currently being proposed for the next generation of manned spacecraft, Orion. These materials insulate the structural components of a spacecraft against the intense thermal environments of atmospheric reentry. Furthermore, these materials are also highly exposed to space environmental hazards like meteoroid and orbital debris impacts. This paper discusses recent impact testing up to 9 km/s, and the findings of the influence of material equation-of-state on the simulation of the impact event to characterize the ballistic performance of these materials. These results will be compared with heritage models1 for these materials developed from testing at lower velocities. Assessments of predicted spacecraft risk based upon these tests and simulations will also be discussed.

Christiansen, E. L.; Davis, B. A.; Miller, J. E.; Bohl, W. E.; Foreman, C. D.

2009-01-01

275

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) laboratory tests have been conducted, (2) with the added trendline analysis method, the accuracy of the data interpretation methodology will be improved and the interfaces and voids can be more reliably detected, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (4) about 80% of the development work for the roof geology mapping program, MRGIS, has completed.

Syd S. Peng

2003-01-15

276

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN MINE ROOF BOLTER DRILLING  

SciTech Connect

In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) laboratory tests have been conducted, (2) with the added trendline analysis method, the accuracy of the data interpretation methodology will be improved, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (3) about one half of the development work for the roof geology mapping program, MRGIS, has completed.

Syd S. Peng

2003-10-15

277

The effectiveness of cool and green roofs as urban heat island mitigation strategies  

NASA Astrophysics Data System (ADS)

Mitigation of the urban heat island (UHI) effect at the city-scale is investigated using the Weather Research and Forecasting (WRF) model in conjunction with the Princeton Urban Canopy Model (PUCM). Specifically, the cooling impacts of green roof and cool (white/high-albedo) roof strategies over the Baltimore-Washington metropolitan area during a heat wave period (7 June-10 June 2008) are assessed using the optimal set-up of WRF-PUCM described in the companion paper by Li and Bou-Zeid (2014). Results indicate that the surface UHI effect (defined based on the urban-rural surface temperature difference) is reduced significantly more than the near-surface UHI effect (defined based on urban-rural 2 m air temperature difference) when these mitigation strategies are adopted. In addition, as the green and cool roof fractions increase, the surface and near-surface UHIs are reduced almost linearly. Green roofs with relatively abundant soil moisture have comparable effect in reducing the surface and near-surface UHIs to cool roofs with an albedo value of 0.7. Significant indirect effects are also observed for both green and cool roof strategies; mainly, the low-level advection of atmospheric moisture from rural areas into urban terrain is enhanced when the fraction of these roofs increases, thus increasing the humidity in urban areas. The additional benefits or penalties associated with modifications of the main physical determinants of green or cool roof performance are also investigated. For green roofs, when the soil moisture is increased by irrigation, additional cooling effect is obtained, especially when the ‘unmanaged’ soil moisture is low. The effects of changing the albedo of cool roofs are also substantial. These results also underline the capabilities of the WRF-PUCM framework to support detailed analysis and diagnosis of the UHI phenomenon, and of its different mitigation strategies.

Li, Dan; Bou-Zeid, Elie; Oppenheimer, Michael

2014-05-01

278

40 CFR 65.45 - External floating roof converted into an internal floating roof.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels § 65.45 External floating roof converted into an internal floating...

2014-07-01

279

40 CFR 65.45 - External floating roof converted into an internal floating roof.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false External floating roof converted into an internal...RULE Storage Vessels § 65.45 External floating roof converted into an internal...regulated material emissions by using an external floating roof converted into an...

2010-07-01

280

The Effects of Roof Membrane Color on Moisture Accumulation in Low-slope Commercial Roof Systems  

SciTech Connect

The use of highly reflective roof membrane systems is being promoted and in some cases required in energy codes and green building codes and standards. Highly reflective membranes, which typically are light in color, have demonstrated reduced overall energy consumption in cooling dominated climate. These membranes also are theorized to reduce the heat island effect. Concern has been expressed about using highly reflective roof membrane systems in cool to cold climate zones because they potentially increase moisture accumulation in roof systems. Roof membranes are vapor retarders. The theory is that highly reflective membranes reflect the heat that could enter the roof assembly, potentially providing a condensing surface on the cold side of the roof assembly during winter months. The other concern is that roof systems using highly reflective membranes will not get hot enough during the summer months to dry out moisture that may have condensed or otherwise entered the roof assembly. This study focuses on mechanically attached, highly reflective, single-ply roof systems installed on low-slope (less than 2:12) structures in cool to cold climate zones. Three sources of data are considered when determining the moisture accumulation potential of these systems. 1.Test roof cuts taken during the winter months 2.Modeling data from a building envelope model specifically designed to evaluate moisture accumulation 3.Data from previous studies to determine the effects of roof membrane color on the drying rate of low-slope roof assemblies

Kehrer, Manfred [ORNL

2011-01-01

281

Three-dimensional building roof boundary extraction using high-resolution aerial image and LiDAR data  

NASA Astrophysics Data System (ADS)

This paper presents a semiautomatic method for rectilinear building roof boundary extraction, based on the integration of high-resolution aerial image and LiDAR (Light Detection and Ranging) data. The proposed method is formulated as an optimization problem, in which a snakes-based objective function is developed to represent the building roof boundaries in an object-space coordinate system. Three-dimensional polylines representing building roof boundaries are obtained by optimizing the objective function using the dynamic programming optimization technique. The results of our experiments showed that the proposed method satisfactorily performed the task of extracting different building roof boundaries from aerial image and LiDAR data.

Dal Poz, A. P.; Fazan, Antonio J.

2014-10-01

282

Effects of mechanical and thermal fatigue on dental drill performance.  

PubMed

Osseous integration of dental implants depends on the use of proper surgical technique during site preparation, including the prevention of thermal injury to the surrounding bone. Heat generation during drilling has been reported to positively correlate with the production of forces at the surgical site. In this study, peak torque and axial load levels were measured during a drilling procedure into a polymeric material simulating the human mandible. Axial rotary milling was performed using 5 different twist drill designs (3i Irrigated Tri-Spade, 3i Disposable, Nobel-Biocare, Straumann, and Lifecore) of 15 to 20 mm in length and 2 to 2.3 mm in diameter, at a free-running rotational speed of 1,500 rpm and continuous feed rate of 3.5 mm/second, to a total depth of 10.5 mm. Ten drills representing each of the 5 types (n = 50) were subjected to 30 individual drill "pecks" and heat-sterilized every 3 "pecks" to determine the effects of cyclic mechanical and thermal loading on drill performance. Normal stress (sigma) and shear stress (tau) were calculated from the kinetic data and drill geometries. A drill efficiency coefficient (mu) was also calculated as the ratio of torsional resistance to translational resistance. Overall, the hypotheses of drill performance dependency on drill type as well as mechanical and thermal accumulated loading were tested and confirmed (P < .05). The 5 drill types produced a range of normal stresses (2.54 to 5.00 MPa), shear stresses (9.69 to 29.71 MPa), and efficiency (1.16 to 3.16) during repeated testing. Scanning electron microscopic images revealed minor deformations in the cutting edges of the tri-spade drills following testing. PMID:11769832

Harris, B H; Kohles, S S

2001-01-01

283

Positive effects of vegetation: urban heat island and green roofs.  

PubMed

This paper attempts to evaluate the positive effects of vegetation with a multi-scale approach: an urban and a building scale. Monitoring the urban heat island in four areas of New York City, we have found an average of 2 °C difference of temperatures between the most and the least vegetated areas, ascribable to the substitution of vegetation with man-made building materials. At micro-scale, we have assessed the effect of surface albedo on climate through the use of a climatological model. Then, using the CO(2) equivalents as indicators of the impact on climate, we have compared the surface albedo, and the construction, replacement and use phase of a black, a white and a green roof. By our analyses, we found that both the white and the green roofs are less impactive than the black one; with the thermal resistance, the biological activity of plants and the surface albedo playing a crucial role. PMID:21481997

Susca, T; Gaffin, S R; Dell'osso, G R

2011-01-01

284

Thermal performance of honeywell double covered liquid solar collector  

NASA Technical Reports Server (NTRS)

The test procedures and results obtained during an evaluation test program to determine the outdoor performance characteristics of the Honeywell liquid solar collector are presented. The program was based on the thermal evaluation of a Honeywell double covered liquid solar collection. Initial plans included the simultaneous testing of a single covered Honeywell collector. During the initial testing, the single covered collector failed due to leakage; thus, testing continued on the double covered collector only. To better define the operating characteristics of the collector, several additional data points were obtained beyond those requested.

Losey, R.

1977-01-01

285

Manufacture and performance of the thermal-bonding Micromegas prototype  

NASA Astrophysics Data System (ADS)

The micro-mesh gaseous structure (Micromegas) has been significantly developed since it was proposed in 1995 at Saclay (France). Some new construction methods different from ``bulk'' etching technique are under R&D. Here we report the results of several prototypes manufactured with thermal-bonding method, The details of this method and the performances of the chambers are presented. For a 200 × 200 m 2 prototype, the energy resolution of 16% (FWHM) for 5.9 keV x-rays is achieved at a gain of 2000–4000. In addition, the sparking-resistant chammber with a Gemanium anode is under studying.

Zhang, Z.; Wang, F.; Yang, Z.; Kang, L.; Guan, L.; Zhang, Y.; Wang, X.; Xu, Z.; Zhao, T.; Liu, S.; An, Q.

2014-10-01

286

A facility for characterizing the steady-state and dynamic thermal performance of microelectromechanical system thermal switches  

NASA Astrophysics Data System (ADS)

A facility to characterize microelectromechanical system (MEMS) thermal switches by measuring two pertinent figures of merit is described. The two figures of merit measured are the ratio of thermal resistance of the switch in the off and on states, Roff/Ron, and the time required to switch from the off to the on state, ?switch. The facility consists of two pieces of equipment. A guard-heated calorimeter is used to measure heat transfer across the thermal switch under steady-state conditions. Measuring heat transfer across a thermal switch in both the off and on states then gives the thermal resistance ratio Roff/Ron. A thin-film radial heat-flux sensor is used to measure heat transfer across the thermal switch under dynamic conditions. Measuring heat transfer across a thermal switch as the switch changes from the off to the on state gives the thermal switching time ?switch. The test facilities enable the control of the applied force on the thermal switch when the thermal switch is on, the thickness of the gas gap when the thermal switch is off, and the gas species and pressure in the thermal switch gas gap. The thermal performance of two MEMS thermal switches employing two different thermal contact materials, a polished silicon surface and an array of liquid-metal microdroplets, is characterized and compared.

Cho, J. H.; Richards, C. D.; Richards, R. F.

2008-03-01

287

Urban reconciliation ecology: the potential of living roofs and walls.  

PubMed

Reconciling human and non-human use of urban regions to support biological conservation represents a major challenge for the 21st century. The concept of reconciliation ecology, by which the anthropogenic environment may be modified to encourage non-human use and biodiversity preservation without compromising societal utilization, potentially represents an appropriate paradigm for urban conservation given the generally poor opportunities that exist for reserve establishment and ecological restoration in urban areas. Two habitat improvement techniques with great potential for reconciliation ecology in urban areas are the installation of living roofs and walls, which have been shown to support a range of taxa at local scales. This paper evaluates the reconciliation potential of living roofs and walls, in particular highlighting both ecological and societal limitations that need to be overcome for application at the landscape scale. We further consider that successful utilization of living roofs and walls for urban reconciliation ecology will rely heavily on the participation of urban citizens, and that a 'citizen science' model is needed to facilitate public participation and support and to create an evidence base to determine their effectiveness. Living roofs and walls are just one aspect of urban reconciliation ecology, but are particularly important 'bottom-up' techniques for improving urban biodiversity that can be performed directly by the citizenry. PMID:21306818

Francis, Robert A; Lorimer, Jamie

2011-06-01

288

Analytical study of nozzle performance for nuclear thermal rockets  

SciTech Connect

Nuclear propulsion has been identified as one of the key technologies needed for human exploration of the Moon and Mars. The Nuclear Thermal Rocket (NTR) uses a nuclear reactor to heat hydrogen to a high temperature followed by expansion through a conventional convergent-divergent nozzle. A parametric study of NTR nozzles was performed using the Rocket Engine Design Expert System (REDES) at the NASA Lewis Research Center. The REDES used the JANNAF standard rigorous methodology to determine nozzle performance over a range of chamber temperatures, chamber pressures, thrust levels, and different nozzle configurations. A design condition was set by fixing the propulsion system exit radius at five meters and throat radius was varied to achieve a target thrust level. An adiabatic wall was assumed for the nozzle, and its length was assumed to be 80 percent of a 15 degree cone. The results conclude that although the performance of the NTR, based on infinite reaction rates, looks promising at low chamber pressures, finite rate chemical reactions will cause the actual performance to be considerably lower. Parameters which have a major influence on the delivered specific impulse value include the chamber temperature and the chamber pressures in the high thrust domain. Other parameters, such as 2-D and boundary layer effects, kinetic rates, and number of nozzles, affect the deliverable performance of an NTR nozzle to a lesser degree. For a single nozzle, maximum performance of 930 seconds and 1030 seconds occur at chamber temperatures of 2700 and 3100 K, respectively.

Davidian, K.O.; Kacynski, K.J.

1991-01-01

289

Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions  

NASA Technical Reports Server (NTRS)

Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k(sub oafi)) is described for use in design and analysis of cryogenic piping systems.

Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

2001-01-01

290

Thermal dependence of sprint performance of the lizard Sceloporus occidentalis.  

PubMed

Sprint velocity of the lizard Sceloporus occidentalis was maximal at preferred body temperature (Tb, 35 degrees C). Mean running velocity (VR) and stride frequency (f) at this temperature were 3.23 +/- 0.7 (mean +/- S.E.M.) ms-1 and 15.6 +/- 0.3 s-1, respectively. VR and f did not change significantly when Tb was raised to 40 degrees C. At Tb values between 25 and 35 degrees C the thermal dependencies of VR (Q10 = 1.23) and f (Q10 = 1.12) were quite low. At Tb values below 25 degrees C the thermal dependence of these factors increased markedly. Stride length (LS) was independent of Tb from 15 to 40 degrees C. Lizards with a Tb of 10 degrees C were largely incapacitated, and VR, f and LS were all greatly reduced. Comparisons with measurements of the contractile properties of skeletal muscle of this species suggest that stride frequency is limited by the twitch contraction time at temperatures below 23 degrees C. At higher temperatures, sprint performance is nearly independent of the thermal effects on the muscles. PMID:3806004

Marsh, R L; Bennett, A F

1986-11-01

291

Thermal{endash}mechanical performance of extreme ultraviolet lithographic reticles  

SciTech Connect

Thermal deformation of reticles will likely become an important consideration for all advanced lithography techniques targeting 130 nm features and below. Such effects can contribute to image placement errors and blur. These issues necessitate the need to quantify the reticle distortion, induced by the absorption of illumination power, for candidate substrate and coating materials. To study the impact of various substrate and coating materials on reticle performance, detailed three-dimensional transient thermal and solid mechanical models have been developed and extensively applied to predict total placement errors, residual placement errors, and blur on an extreme ultraviolet lithography (EUVL) reticle during scanning. The thermal model includes a bidirectional scanning heat source representative of the illumination incident on the reticle. The heat loads on the reticle are characteristic of an EUVL engineering test stand with a wafer throughput of twenty 200 mm wafers per hour (assuming 80{percent} die coverage and 68{percent} exposure time). This article includes the results which describe the impact of (1) different substrate materials, (2) various degrees of contact conductance between the reticle and chuck, (3) pattern density and arrangement, and (4) temperature variations across the chuck. {copyright} {ital 1998 American Vacuum Society.}

Gianoulakis, S.E. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Ray-Chaudhuri, A.K. [Sandia National Laboratories, Livermore, California 94550 (United States)] [Sandia National Laboratories, Livermore, California 94550 (United States)

1998-11-01

292

Thermal performance of microinverters on dual-axis trackers  

NASA Astrophysics Data System (ADS)

Time-series insolation, environmental, thermal and power data were analyzed in a statistical analytical approach to identify the thermal performance of microinverters on dual-axis trackers under real-world operating conditions. This study analyzed 24 microinverters connected to 8 different brands of photovoltaic (PV) modules from July through October 2013 at the Solar Durability and Lifetime Extension (SDLE) SunFarm at Case Western Reserve University. Exploratory data analysis shows that the microinverter's temperature is strongly correlated with ambient temperature and PV module temperature, and moderately correlated with irradiance and AC power. Noontime data analysis reveals the variations of thermal behavior across different brands of PV module. Hierarchical clustering using the Euclidean distance measure principle was applied to noontime microinverter temperature data to group the similarly behaved microinverters. A multiple regression predictive model has been developed based on ambient temperature, PV module temperature, irradiance and AC power data to predict the microinverters temperature connected with different brands PV modules on dual-axis trackers.

Hossain, Mohammad A.; Peshek, Timothy J.; Xu, Yifan; Ji, Liang; Sun, Jiayang; Abramson, Alexis; French, Roger H.

2014-10-01

293

Determination of thermal performance characteristics of modular passive solar storage walls  

Microsoft Academic Search

A conceptual study of testing procedures to determine thermal performance characteristics of Trombe-Wall type passive solar storage wall systems has been performed. In the study, a finite-difference thermal model of a passive solar storage wall in a test facility was used to predict the wall thermal performance in a particular climatic location. The simulated test results were used in a

W. J. Kennish; M. Ahmed; M. McCabe; M. McKinstry

1980-01-01

294

Roofing as a source of nonpoint water pollution  

Microsoft Academic Search

Sixteen wooden structures with two roofs each were installed to study runoff quality for four commonly used roofing materials (wood shingle, composition shingle, painted aluminum, and galvanized iron) at Nacogdoches, Texas. Each roof, either facing NW or SE, was 1.22m wide×3.66m long with a 25.8% roof slope. Thus, there were 32 alternatively arranged roofs, consisting of four roof types×two aspects×four

Mingteh Chang; Matthew W. McBroom; R. Scott Beasley

2004-01-01

295

Improving the performance of lysimeters with thermal imaging  

NASA Astrophysics Data System (ADS)

Precision weighing lysimeters generate data of evapotranspiration (ET) at a high resolution in the order of 0.01 to 0.05 mm. Though this resolution is often reported as the accuracy of the lysimeter, it is in fact the precision of the weighing device. The accuracy of a lysimeter is heavily dependent on its ability to duplicate environmental conditions of its surroundings. In general, measurement errors will decrease with increasing lysimeter dimension, primarily because a larger part of the lysimeter is unaffected by its boundaries and because heterogeneities in soil hydraulic properties and micro-climate are more averaged out. However, the cost of large lysimeters make them unattractive and scientists often choose for more economical solutions, optimizing between lysimeter dimensions and costs. Instead of investing in large lysimeters or putting effort in duplicating environmental conditions, we invested in monitoring the surface temperature of zero tension lysimeters with a thermal infrared camera to detect deviations in ET. In such a system, measurement errors caused by deviations in moisture content can be compensated, without the struggle of controlling the lysimeter moisture content with pressure plates and vacuum pumps or preventing wall flow. Other advantages of using thermal imaging are that (i) measurements of ET can be extrapolated to much larger areas than the surface area of most conventional lysimeters, and (ii) ET can be split into soil evaporation and transpiration, which allows us to study the effects of the vegetation structure on the water balance. Several experiments were performed to estimate differences in ET between lysimeters based on the radiometric surface temperature. Two simple methods, 1) linear scaling and 2) a comparison of the surface energy balance were applied to translate differences in surface temperature to differences in ET. We examined the application of both methods on bare sand, moss and grass. We show that the performance of lysimeters can be monitored and improved with the aid of thermal imaging. For example, estimated ET based on thermal images of moss lysimeters showed a model efficiency (Nash Sutcliffe) of 0.94 and 0.93 and a RMSE of 0.02 and 0.03 mm for method 1 and 2 respectively. However, for bare sand the model efficiency was much lower: 0.54 and 0.59 with a RMSE of 0.53 and 0.60 mm for method 1 and 2 respectively. This poor performance is caused by the large variation in albedo of bare sand under moist and dry conditions, affecting the available energy for evaporation.

Voortman, Bernard; Bartholomeus, Ruud; Witte, Jan-Philip

2014-05-01

296

Miniaturized high-performance starring thermal imaging system  

NASA Astrophysics Data System (ADS)

A high resolution thermal imaging system was developed based on a 384 X 288 mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) detection module with a 2 X 2 microscan for improved geometrical resolution. Primary design goal was a long identification range of 3 km and high system performance for adverse weather conditions achieved by a system with small entrance pupil and minimized dimensions to fit for integration in existing apertures of armored vehicles, reconnaissance systems and stabilized platforms. A staring FPA module with its potential for long integration times together with a microscan for improved geometrical resolution provides the answers best fit to these requirements. A robust microscanner was developed to fit for military requirements and integrated with AIM's 384 X 288 MCT MWIR module and data processing. The modules allow for up to 2 ms integration time with 25 Hz frame rate and output a 768 X 576 high resolution CCIR standard image. The video image processing (VIP) provides the calculation power for scene based self learning nonuniformity correction (NUC) algorithms to save calibration sources. This NUC algorithm allows take into account non linear effects for unsurpassed performance in highly dynamic scenes. The detection module and VIP are designed to interface with STN's mature system electronics, used e.g. in hundreds of OPHELIOS thermal camera sets fielded. The system electronics provides a lot of different interface features like double serial control bus (CANBUS) interface, analog and digital outputs as well as different video outputs. The integrated graphic generation part allows to put advanced graphic overlays to the thermal image and also to external video signals via the video input feature. This electronics provides the power supply for the whole thermal imaging system as well as different processor controlled algorithms for field of view or zoom drives, focus drives, athermalization and temperature control of the FLIR. A new zoom lens F/2.0 allows to select field of views from 2 degree to 15 degrees horizontal. This covers a wide area of military and paramilitary applications. The whole camera is miniaturized to fit into existing gunner and commander sights for main battle tanks as well as for infantry fighting vehicles. The overall design is compatible in optical, electrical and mechanical direction with the fielded OPHELIOS cameras and so an easy upgrade for existing fire control, reconnaissance and platform systems. The overall design is made under consideration of mil standard environments and is able to withstand vehicle, airborne and shipborne stress. The presentation gives an overview of the different components of the new camera system. Theoretical range performance data are discussed together with measured NETD, MTF and MRTD data of the unit.

Cabanski, Wolfgang A.; Breiter, Rainer; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann; Ennenga, L.; Lipinski, Ulrich M.; Wehrhahn, T.

2000-07-01

297

Standard Guide for Specifying Thermal Performance of Geothermal Power Systems  

E-print Network

1.1 This guide covers power plant performance terms and criteria for use in evaluation and comparison of geothermal energy conversion and power generation systems. The special nature of these geothermal systems makes performance criteria commonly used to evaluate conventional fossil fuel-fired systems of limited value. This guide identifies the limitations of the less useful criteria and defines an equitable basis for measuring the quality of differing thermal cycles and plant equipment for geothermal resources. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

American Society for Testing and Materials. Philadelphia

2000-01-01

298

A performance and reliability model for thermal barrier coatings  

NASA Technical Reports Server (NTRS)

A modeling technique for predicting the performance and reliability of TBC's is being developed at Solar Turbines Incorporated. The concept combines experimental coating property data with finite element analyses to predict the thermal and mechanical behavior of coating systems in service. A key feature of Solar's approach is the use of a four point flexure test to estimate coating strength distributions and to predict coating failure probability. This model was used to evaluate the effect of physical variations on coating performance in high heat flux rocket engine applications for NASA. Current work, promoted by Caterpillar Tractor Company for diesel engine applications, is being conducted to measure coating strength as a function of temperature, and future work will document strength degradation with time at temperature. Solar's interest lies in the application of TBCs to gas turbine engine components.

Batakis, A. P.

1985-01-01

299

Thermal Performance of Orion Active Thermal Control System With Seven-Panel Reduced-Curvature Radiator  

NASA Technical Reports Server (NTRS)

The active thermal control system (ATCS) of the crew exploration vehicle (Orion) uses radiator panels with fluid loops as the primary system to reject heat from spacecraft. The Lockheed Martin (LM) baseline Orion ATCS uses eight-panel radiator coated with silver Teflon coating (STC) for International Space Station (ISS) missions, and uses seven-panel radiator coated with AZ 93 white paint for lunar missions. As an option to increase the radiator area with minimal impact on other component locations and interfaces, the reduced-curvature (RC) radiator concept was introduced and investigated here for the thermal perspective. Each RC radiator panel has 15 percent more area than each Lockheed Martin (LM) baseline radiator panel. The objective was to determine if the RC seven-panel radiator concept could be used in the ATCS for both ISS and lunar missions. Three radiator configurations the LM baseline, an RC seven-panel radiator with STC, and an RC seven-panel radiator with AZ 93 coating were considered in the ATCS for ISS missions. Two radiator configurations the LM baseline and an RC seven-panel radiator with AZ 93 coating were considered in the ATCS for lunar missions. A Simulink/MATLAB model of the ATCS was used to compute the ATCS performance. Some major hot phases on the thermal timeline were selected because of concern about the large amount of water sublimated for thermal topping. It was concluded that an ATCS with an RC seven-panel radiator could be used for both ISS and lunar missions, but with two different coatings STC for ISS missions and AZ 93 for lunar missions to provide performance similar to or better than that of the LM baseline ATCS.

Wang, Xiao-Yen J.; Yuko, James R.

2010-01-01

300

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, potash, salt etc. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on such information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. A new mechanical approach to estimate rock strengths using the acquired drilling parameters has been proposed. This approach takes a number of important factors, that have never been studied in the previous researches, into the considerations. Good results have been shown using the new approach on the testing data.

Syd S. Peng

2002-01-15

301

OPTIMIZING GREEN ROOF TECHNOLOGIES IN THE MIDWEST  

EPA Science Inventory

Green roofs, while extensively used in Europe, are an emerging technology in the U.S. They have an array of potential benefits (including improved storm water management, increased energy conservation of buildings, reduced urban heat island effects, and extended roof life) ...

302

Lightweight, self-ballasting photovoltaic roofing assembly  

DOEpatents

A photovoltaic roofing assembly comprises a roofing membrane (102), a plurality of photovoltaic modules (104, 106, 108) disposed as a layer on top of the roofing membrane (102), and a plurality of pre-formed spacers, pedestals or supports (112, 114, 116, 118, 120, 122) which are respectively disposed below the plurality of photovoltaic modules (104, 106, 108) and integral therewith, or fixed thereto. Spacers (112, 114, 116, 118, 120, 122) are disposed on top of roofing membrane (102). Membrane (102) is supported on conventional roof framing, and attached thereto by conventional methods. In an alternative embodiment, the roofing assembly may have insulation block (322) below the spacers (314, 314', 315, 315'). The geometry of the preformed spacers (112, 114, 116, 118, 120, 122, 314, 314', 315, 315') is such that wind tunnel testing has shown its maximum effectiveness in reducing net forces of wind uplift on the overall assembly. Such construction results in a simple, lightweight, self-ballasting, readily assembled roofing assembly which resists the forces of wind uplift using no roofing penetrations.

Dinwoodie, Thomas L. (Berkeley, CA)

1998-01-01

303

Lightweight, self-ballasting photovoltaic roofing assembly  

DOEpatents

A photovoltaic roofing assembly comprises a roofing membrane (102), a plurality of photovoltaic modules (104, 106, 108) disposed as a layer on top of the roofing membrane (102), and a plurality of pre-formed spacers, pedestals or supports (112, 114, 116, 118, 120, 122) which are respectively disposed below the plurality of photovoltaic modules (104, 106, 108) and integral therewith, or fixed thereto. Spacers (112, 114, 116, 118, 120, 122) are disposed on top of roofing membrane (102). Membrane (102) is supported on conventional roof framing, and attached thereto by conventional methods. In an alternative embodiment, the roofing assembly may have insulation block (322) below the spacers (314, 314', 315, 315'). The geometry of the preformed spacers (112, 114, 116, 118, 120, 122, 314, 314', 315, 315') is such that wind tunnel testing has shown its maximum effectiveness in reducing net forces of wind uplift on the overall assembly. Such construction results in a simple, lightweight, self-ballasting, readily assembled roofing assembly which resists the forces of wind uplift using no roofing penetrations.

Dinwoodie, T.L.

1998-05-05

304

Factors Influencing Arthropod Diversity on Green Roofs  

Microsoft Academic Search

Green roofs have potential for providing substantial habitat to plants, birds, and arthropod species that are not well supported by other urban habitats. Whereas the plants on a typical green roof are chosen and planted by people, the arthropods that colonize it can serve as an indicator of the ability of this novel habitat to support a diverse community of

Bracha Y Schindler; Alden B Griffith; Kristina N Jones

2011-01-01

305

Lightweight, self-ballasting photovoltaic roofing assembly  

DOEpatents

A photovoltaic roofing assembly comprises a roofing membrane (102), a plurality of photovoltaic modules (104, 106, 108) disposed as a layer on top of the roofing membrane (102), and a plurality of pre-formed spacers, pedestals or supports (112, 114, 116, 118, 120, 122) which are respectively disposed below the plurality of photovoltaic modules (104, 106, 108) and integral therewith, or fixed thereto. Spacers (112, 114, 116, 118, 120, 122) are disposed on top of roofing membrane (102). Membrane (102) is supported on conventional roof framing, and attached thereto by conventional methods. In an alternative embodiment, the roofing assembly may have insulation block (322) below the spacers (314, 314', 315, 315'). The geometry of the pre-formed spacers (112, 114, 116, 118, 120, 122, 314, 314', 315, 315') is such that wind tunnel testing has shown its maximum effectiveness in reducing net forces of wind uplift on the overall assembly. Such construction results in a simple, lightweight, self-ballasting, readily assembled roofing assembly which resists the forces of wind uplift using no roofing penetrations.

Dinwoodie, Thomas L.

2006-02-28

306

4 Living roofs in 3 locations: Does configuration affect runoff mitigation?  

NASA Astrophysics Data System (ADS)

Four extensive living roofs and three conventional (control) roofs in Auckland, New Zealand have been evaluated over periods of 8 months to over 2 yrs for stormwater runoff mitigation. Up to 56% cumulative retention was measured from living roofs with 50-150 mm depth substrates installed over synthetic drainage layers, and with >80% plant coverage. Variation in cumulative %-retention amongst sites is attributed to different durations of monitoring, rather than actual performance. At all sites, runoff rarely occurred at all from storms with less than 25 mm of precipitation, from the combined effects of substrates designed to maximize moisture storage and because >90% of individual events were less than 25 mm. Living roof runoff depth per event is predicted well by a 2nd order polynomial model (R2 = 0.81), again demonstrating that small storms are well managed. Peak flow per event from the living roofs was 62-90% less than a corresponding conventional roof's runoff. Seasonal retention performance decreased slightly in winter, but was nonetheless substantial, maintaining 66% retention at one site compared to 45-93% in spring-autumn at two sites. Peak flow mitigation did not vary seasonally. During a 4-month period of concurrent monitoring at all sites, varied substrate depth did not influence runoff depth (volume), %-retention, or %-peak flow mitigation compared to a control roof at the same site. The magnitude of peak flow was greater from garden shed-scale living roofs compared to the full-scale living roofs. Two design aspects that could be manipulated to increase peak flow mitigation include lengthening the flow path through the drainage layer to vertical gutters and use of flow-retarding drainage layer materials.

Fassman-Beck, Elizabeth; Voyde, Emily; Simcock, Robyn; Hong, Yit Sing

2013-05-01

307

Thermal Performance of Cryogenic Multilayer Insulation at Various Layer Spacings  

NASA Technical Reports Server (NTRS)

Multilayer insulation (MLI) has been shown to be the best performing cryogenic insulation system at high vacuum (less that 10 (exp 3) torr), and is widely used on spaceflight vehicles. Over the past 50 years, many investigations into MLI have yielded a general understanding of the many variables that are associated with MLI. MLI has been shown to be a function of variables such as warm boundary temperature, the number of reflector layers, and the spacer material in between reflectors, the interstitial gas pressure and the interstitial gas. Since the conduction between reflectors increases with the thickness of the spacer material, yet the radiation heat transfer is inversely proportional to the number of layers, it stands to reason that the thermal performance of MLI is a function of the number of layers per thickness, or layer density. Empirical equations that were derived based on some of the early tests showed that the conduction term was proportional to the layer density to a power. This power depended on the material combination and was determined by empirical test data. Many authors have graphically shown such optimal layer density, but none have provided any data at such low densities, or any method of determining this density. Keller, Cunnington, and Glassford showed MLI thermal performance as a function of layer density of high layer densities, but they didn't show a minimal layer density or any data below the supposed optimal layer density. However, it was recently discovered that by manipulating the derived empirical equations and taking a derivative with respect to layer density yields a solution for on optimal layer density. Various manufacturers have begun manufacturing MLI at densities below the optimal density. They began this based on the theory that increasing the distance between layers lowered the conductive heat transfer and they had no limitations on volume. By modifying the circumference of these blankets, the layer density can easily be varied. The simplest method of determining the thermal performance of MLI at cryogenic temperature is by boil-off calorimetry. Several blankets were procured and tested at various layer densities at the Cryogenics Test Laboratory at Kennedy Space Center. The densities that the blankets were tested over covered a wide range of layer densities including the analytical minimum. Several of the blankets were tested at the same insulation thickness while changing the layer density (thus a different number of reflector layers). Optimizing the layer density of multilayer insulation systems for heat transfer would remove a layer density from the complex method of designing such insulation systems. Additional testing was performed at various warm boundary temperatures and pressures. The testing and analysis was performed to simplify the analysis of cryogenic thermal insulation systems. This research was funded by the National Aeronautics and Space Administration's Exploration Technology Development Program's Cryogenic Fluid Management Project

Johnson, Wesley Louis

2010-01-01

308

Building America Best Practices Series, Volume 6: High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems  

SciTech Connect

This guide is was written by PNNL for the US Department of Energy's Building America program to provide information for residential production builders interested in building near zero energy homes. The guide provides indepth descriptions of various roof-top photovoltaic power generating systems for homes. The guide also provides extensive information on various designs of solar thermal water heating systems for homes. The guide also provides construction company owners and managers with an understanding of how solar technologies can be added to their homes in a way that is cost effective, practical, and marketable. Twelve case studies provide examples of production builders across the United States who are building energy-efficient homes with photovoltaic or solar water heating systems.

Baechler, Michael C.; Gilbride, Theresa L.; Ruiz, Kathleen A.; Steward, Heidi E.; Love, Pat M.

2007-06-04

309

Determination of thermal performance characteristics of modular passive solar storage walls. Final report  

SciTech Connect

A conceptual study of testing procedures to determine thermal performance characteristics of Trombe-wall-type passive solar storage wall systems has been performed. In the study, a finite-difference thermal model of a passive solar storage wall in a test facility was used to predict the wall thermal performance in a particular climatic location. The simulated test results were used in a multiple regression analysis to characterize the thermal performance of a test wall. These characteristics were then used in a simplified calculation procedure to predict the thermal performance of the solar storage wall in different climatic regions.

Kennish, W.; McCabe, M.

1980-10-01

310

30 CFR 75.222 - Roof control plan-approval criteria.  

Code of Federal Regulations, 2011 CFR

...roof support using mining machines with integral roof bolters...roof bolts with roof bolting machines and continuous-mining machines with integral roof bolters...effectiveness of the two-way communication systems; and (vi)...

2011-07-01

311

30 CFR 75.222 - Roof control plan-approval criteria.  

Code of Federal Regulations, 2010 CFR

...of roof support using mining machines with integral roof bolters...roof bolts with roof bolting machines and continuous-mining machines with integral roof bolters...transportation from the section to the main line. (3) The plan...

2010-07-01

312

Green roof impact on the hydrological cycle components  

NASA Astrophysics Data System (ADS)

In the last decades the importance of storm water management in urban areas has increased considerably, due to both urbanization extension and to a greater concern for environment pollution. Traditional storm water control practices, based on the "all to the sewer" attitude, rely on conveyance to route storm water runoff from urban impervious surfaces towards the nearby natural water bodies. In recent years, infiltration facilities are receiving an increasing attention, due to their particular efficiency in restoring a balance in hydrological cycle quite equal to quite pre-urbanization condition. In particular, such techniques are designed to capture, temporarily retain and infiltrate storm water, promote evapotranspiration and harvest water at the source, encouraging in general evaporation, evapotranspiration, groundwater recharge and the re-use of storm water. Green roofs are emerging as an increasingly popular Sustainable Urban Drainage Systems (SUDS) technique for urban storm water management. Indeed, they are able to operate hydrologic control over storm water runoff: they allow a significant reduction of peak flows and runoff volumes collected by drainage system, with a consequent reduction of flooding events and pollution masses discharges by CSO. Furthermore green roofs have a positive influence on the microclimate in urban areas by helping in lower urban air temperatures and mitigate the heat island effect. Last but not least, they have the advantage of improving the thermal insulation of buildings, with significant energy savings. A detailed analysis of the hydrological dynamics, connected both with the characteristics of the climatic context and with the green roof technical design, is essential in order to obtain a full characterization of the hydrologic behavior of a green roof system and its effects on the urban water cycle components. The purpose of this paper is to analysis the hydrological effects and urban benefits of the vegetation cover of a building by installing green roofs and, thus, providing a conversion of rooftops in pervious areas; the objective is modeling hydrological fluxes (interception, evapotranspiration, soil water fluxes in the surface and hypodermic components) in relation to climate forcing, basic technology components and geometric characteristics of green roof systems (thickness of the stratigraphy, soil layers and materials, vegetation typology and density). The sensitivity analysis of hydrological processes at different hydrological, climatic and geometric parameters has allowed to draw some general guidelines useful in the design and construction of this type of drainage systems.

Lamera, Carlotta; Rulli, Maria Cristina; Becciu, Gianfranco; Rosso, Renzo

2013-04-01

313

A guidebook for insulated low-slope roof systems. IEA Annex 19, Low-slope roof systems: International Energy Agency Energy Conservation in Buildings and Community Systems Programme  

SciTech Connect

Low-slope roof systems are common on commercial and industrial buildings and, to a lesser extent, on residential buildings. Although insulating materials have nearly always been a component of low-slope roofs, the amount of insulation used has increased in the past two decades because of escalation of heating and cooling costs and increased awareness of the need for energy conservation. As the amount of insulation has increased, the demand has intensified for design, installation, and maintenance information specifically for well-insulated roofs. Existing practices for design, installation, and maintenance of insulated roofs have evolved from experience. Typically, these practices feature compromises due to the different properties of materials making up a given roof system. Therefore, they should be examined from time to time to ensure that they are appropriate as new materials continue to enter the market and as the data base on existing systems expands. A primary purpose of this International Energy Agency (IEA) study is to assess current roofing insulation practices in the context of an accumulating data base on performance.

Not Available

1994-02-01

314

The technical viability of alternative blowing agents in polyisocyanurate roof insulation  

SciTech Connect

This paper is a progress report on the initial results of laboratory test on a set of prototypical, experimental, polyisocyanurate (PIR) laminate boardstock produced to evaluate the viability of alternative hydrochlorofluorocarbons (HCFCs) as blowing agents. All boardstock was produced from the same formulation and was not optimized for thermal performance. Boardstock made in the future may differ in performance from this set. Thermal resistance values are reported for PIR boards prepared with CFC-11, HCFC-123, HCFC-141b, and two blends of HCFC-123 and HCFC-141b. The primary purpose of the laboratory tests is to answer a key question: will foams produced with the alternative blowing agents yield the same outstanding thermal properties obtained with CFC-11 The CFC problem is enormous. Reductions in the production of CFC-11 and CFC-12 may lead to less efficient substitutes and increase annual US energy consumption for building applications alone by one (10{sup 15}Btu) or more (1). The current effort is a cooperative industry/government program to avoid this undesirable effect by establishing the viability of alternative blowing agents. The research project for CFC alternatives resulted from two workshops that involved participants from industry, government, and academia (2). At the initial workshop the participants prioritized 29 research projects of a CFC research menu. The second workshop focused on a single cooperative project, the long-term performance of substitute insulations containing HCFC-123 and HCFC-141b for roofing applications. 20 refs., 5 figs., 7 tabs.

McElroy, D.L.; Graves, R.S.; Weaver, F.J.; Yarbrough, D.W.

1990-01-01

315

Estimating the effect of using cool coatings on energy loads and thermal comfort in residential buildings in various climatic conditions  

Microsoft Academic Search

The impact from using cool roof coatings on the cooling and heating loads and the indoor thermal comfort conditions of residential buildings for various climatic conditions is estimated. The energy cooling loads and peak cooling demands are estimated for different values of roof solar reflectance and roof U-value. The results show that increasing the roof solar reflectance reduces cooling loads

A. Synnefa; M. Santamouris; H. Akbari

2007-01-01

316

Roof shading and wall glazing techniques for reducing peak building heating and cooling loads. Final report  

SciTech Connect

The roof shading device proved to be effective in reducing peak building cooling loads under both actual testing conditions and in selected computer simulations. The magnitude of cooling load reductions varied from case to case depending on individual circumstances. Key variables that had significant impacts on its thermal performance were the number of months of use annually, the thermal characteristics of the roof construction, hours of building use, and internal gains. Key variables that had significant impacts upon economic performance were the costs of fuel energy for heating and cooling, and heating and cooling equipment efficiency. In general, the more sensitive the building is to climate, the more effective the shading device will be. In the example case, the annual fuel savings ($.05 psf) were 6 to 10% of the estimated installation costs ($.50 to .75 psf). The Trombe wall installation at Roxborough High School proved to be effective in collecting and delivering significant amounts of solar heat energy. It was also effective in conserving heat energy by replacing obsolete windows which leaked large amounts of heat from the building. Cost values were computed for both solar energy contributions and for heat loss reductions by window replacement. Together they amount to an estimated three hundred and ninety dollars ($390.00) per year in equivalent electric fuel costs. When these savings are compared with installation cost figures it is apparent that the Trombe wall installation as designed and installed presents a potentially cost-effective method of saving fuel costs. The study results indicate that improved Trombe wall efficiency can be achieved by making design and construction changes to reduce or eliminate outside air leakage into the system and provide automatic fan control.

Ueland, M.

1981-08-01

317

SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature  

SciTech Connect

In September 2003, in the wake of Hurricane Isabel, JLab was without power for four days after a tree fell on the main power lines feeding the site. This was long enough to lose insulating vacuum in the cryomodules and cryogenic systems resulting in the whole accelerator warming up and the total loss of the liquid helium inventory. This thermal cycle stressed many of the cryomodule components causing several cavities to become inoperable due to helium to vacuum leaks. At the same time the thermal cycle released years of adsorbed gas from the cold surfaces. Over the next days and weeks this gas was pumped away, the insulating vacuum was restored and the machine was cooled back down and re-commissioned. In a testament to the robustness of SRF technology, only a small loss in energy capability was apparent, although individual cavities had quite different field-emission characteristics compared to before the event. In Summer 2004 a section of the machine was again cycled to room temperature during the long maintenance shutdown. We report on the overall SRF performance of the machine after these major disturbances and on efforts to characterize and optimize the new behavior for high-energy running.

Robert Rimmer; Jay Benesch; Joseph Preble; Charles Reece

2005-05-01

318

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing  

SciTech Connect

Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. The incidents related to rainwater leakage and condensation concerns. Condensation concerns have been extensively studied by others and are not further discussed in this report. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

Grin, A.; Smegal, J.; Lstiburek, J.

2013-10-01

319

Design of a neutron gauge for the detection and measurement of water ingression in flat roofs  

Microsoft Academic Search

This paper reports on a portable neutron gauge designed to detect water ingression in flat roofs and to measure with good accuracy the moisture content in the roofing materials. The gauge consists of a small ²⁵²Cf neutron source inserted in a collimator head made of borated paraffin contained in a steel vessel. Neutron detection is performed with a boron trifluoride

H. W. Bonin; C. J. Thorp

1991-01-01

320

THERMAL PERFORMANCE OF RADIOACTIVE MATERIAL PACKAGES IN TRANSPORT CONFIGURATION  

SciTech Connect

Drum type packages are routinely used to transport radioactive material (RAM) in the U.S. Department of Energy (DOE) complex. These packages are designed to meet the federal regulations described in 10 CFR Part 71. The packages are transported in specially designed vehicles like Safe Secure Transport (SST) for safety and security. In the transport vehicles, the packages are placed close to each other to maximize the number of units in the vehicle. Since the RAM contents in the packagings produce decay heat, it is important that they are spaced sufficiently apart to prevent overheating of the containment vessel (CV) seals and the impact limiter to ensure the structural integrity of the package. This paper presents a simple methodology to assess thermal performance of a typical 9975 packaging in a transport configuration.

Gupta, N.

2010-03-04

321

Parametric study of solar thermal rocket nozzle performance  

NASA Technical Reports Server (NTRS)

This paper details a numerical investigation of performance losses in low-thrust solar thermal rocket nozzles. The effects of nozzle geometry on three types of losses were studied; finite rate dissociation-recombination kinetic losses, two dimensional axisymmetric divergence losses, and compressible viscous boundary layer losses. Short nozzle lengths and supersonic flow produce short residence times in the nozzle and a nearly frozen flow, resulting in large kinetic losses. Variations in geometry have a minimal effect on kinetic losses. Divergence losses are relatively small, and careful shaping of the nozzle can nearly eliminate them. The boundary layer in these small nozzles can grow to a major fraction of nozzle radius, and cause large losses. These losses are attributed to viscous drag on the nozzle walls and flow blockage by the boundary layer, especially in the throat region. Careful shaping of the nozzle can produce a significant reduction in viscous losses.

Pearson, J. Boise; Landrum, D. Brian; Hawk, Clark W.

1995-01-01

322

Thermal Performance of Capillary Pumped Loops Onboard Terra Spacecraft  

NASA Technical Reports Server (NTRS)

The Terra spacecraft is the flagship of NASA's Earth Science Enterprise. It provides global data on the state of atmosphere, land and oceans, as well as their interactions with solar radiation and one another. Three Terra instruments utilize Capillary Pumped Heat Transport System (CPHTS) for temperature control: Each CPHTS, consisting of two capillary pumped loops (CPLs) and several heat pipes and electrical heaters, is designed for instrument heat loads ranging from 25W to 264W. The working fluid is ammonia. Since the launch of the Terra spacecraft, each CPHTS has been providing a stable interface temperature specified by the instrument under all modes of spacecraft and instrument operations. The ability to change the CPHTS operating temperature upon demand while in service has also extended the useful life of one instrument. This paper describes the design and on-orbit performance of the CPHTS thermal systems.

Ku, Jentung; Ottenstein, Laura; Butler, Charles D.; Swanson, Theodore; Thies, Diane

2004-01-01

323

LARGO hot water system thermal performance test report  

NASA Technical Reports Server (NTRS)

The thermal performance tests and results on the LARGO Solar Hot Water System under natural environmental conditions is presented. Some objectives of these evaluations are to determine the amount of energy collected, the amount of energy delivered to the household as contributed by solar power supplied to operate the system and auxiliary power to maintain tank temperature at proper level, overall system efficiency and to determine temperature distribution within the tank. The Solar Hot Water system is termed a Dump-type because of the draining system for freeze protection. The solar collector is a single glazed flat plate. An 82-gallon domestic water heater is provided as the energy storage vessel. Water is circulated through the collector and water heater by a 5.3 GPM capacity pump, and control of the pump motor is achieved by a differential temperature controller.

1978-01-01

324

A comprehensive numerical model examining the thermal performance of airships  

NASA Astrophysics Data System (ADS)

A novel computational model for analyzing the airship's transient thermal performance under different environmental conditions was developed. Radiative heat transfer and natural convection inside the airship were modeled using the control volume method. The Semi-Implicit Method aiming at the Pressure-Linked Equations algorithm was adopted to solve the control equations. Such approach was able to take into account the solar irradiative heat flux, the infrared radiation at different locations, and the convection both inside and outside the airship. The simulation results, showing the detailed distributions of temperature and velocity on the envelope and inside the airship, were in good agreement with the experimental measurements. The influences of solar position and material radiative properties on temperature distribution, as well as natural convective flow inside airship, were further simulated and discussed.

Wang, Y. W.; Yang, C. X.

2011-11-01

325

Impact of operation and control strategy on the performance of a thermal energy storage system  

Microsoft Academic Search

The method of operation and control of a thermal energy storage system will have significant impact on the value of the system to both the customer and the utility. The annul performance for different operating and control strategies of thermal energy storage systems can be compared by simulation analysis. In the paper, simulation of the annual performance of a thermal

1986-01-01

326

Thermal performance of a passive solar house for continental climate, in Florina, north-western Greece  

Microsoft Academic Search

This paper presents the thermal performance of a single-family house in Florina, north- western Greece. As the winter thermal performance was analysed in a previous paper by the authors, this paper focuses on the thermal comfort conditions, which prevail in the house during the intermediate seasons (spring and autumn) and during the summer. This is achieved through two different approaches.

Achilleas Stoios; Flora Bougiatioti; Aineias Oikonomou

327

Simulated performance of storage materials for pebble bed thermal energy storage (TES) systems  

Microsoft Academic Search

A simplified one dimensional single phase model for an oil pebble thermal energy storage system is used to examine the thermal performance of three solid sensible heat pebble materials. These are fused silica glass, alumina and stainless steel. The model is validated with experimental results and reasonable agreement is achieved between experiment and simulation. The thermal performance of these materials

A. Mawire; M. McPherson; R. R. J. van den Heetkamp; S. J. P. Mlatho

2009-01-01

328

Performance analysis of solar water heater combined with heat pump using refrigerant mixture  

Microsoft Academic Search

In the research presented in this paper the thermal performance of a solar water heater combined with a heat pump is studied. A solar collector was modified from corrugated metal roofing with a copper tube attached beneath. The performance of the solar water heater was tested, and models for the collector efficiency and storage tank were developed and used for

Atipoang Nuntaphan; Choosak Chansena; Tanongkiat Kiatsiriroat

2009-01-01

329

Thermal hydraulic performance analysis of a small integral pressurized water reactor core  

E-print Network

A thermal hydraulic analysis of the International Reactor Innovative and Secure (IRIS) core has been performed. Thermal margins for steady state and a selection of Loss Of Flow Accidents have been assessed using three ...

Blair, Stuart R. (Stuart Ryan), 1972-

2003-01-01

330

Thermal Performance of Poly Alpha Olefin Nanofluid with Spherical and Non-spherical Nanoparticles  

E-print Network

Research on nanofluids has been undertaken for several years because of the reported enhancements of thermal properties such as thermal conductivity and enhanced heat transfer performance in laminar flow. Nanofluid is the fluid where nanoparticles...

Park, Chan Hyun

2012-07-16

331

Green Roof Effect on Arthropod Biodiversity By Caitlin Race  

E-print Network

were collected, with a Shannon diversity index of 2.08. In the paved area of the roof, only 4 arthropodGreen Roof Effect on Arthropod Biodiversity By Caitlin Race A green roof is a roof sampling date. Samples were frozen for a period of one day before the arthropods were sorted out

Ginzel, Matthew

332

Rectilinear building roof contour extraction based on snakes and dynamic programming  

NASA Astrophysics Data System (ADS)

This paper presents a method for extracting building roof contours from digital images collected over urban landscapes. The proposed method utilizes an energy function based on snakes that represents building roof contours in digital images and is optimized with a dynamic programming (DP) algorithm. Because most building roof contours are characterized by rectilinear sides that intercept at right angles, appropriate geometric constraints are enforced in the previously reported snake-based energy function. The main advantage of using the DP algorithm for optimizing the proposed snake-based energy function is its better radius of convergence compared to that typically obtained in the original solution based on variational approaches. Experimental evaluation, which included visual inspections and numerical analyses, was performed using real data, and the obtained results demonstrated that the proposed method has significant potential for successfully extracting building roof contours from digital images.

Fazan, Antonio Juliano; Dal Poz, Aluir Porfírio

2013-12-01

333

HIGH-PERFORMANCE PHASECHANGE THERMAL ENERGY STORAGE USING SPHERICAL CAPSULES  

Microsoft Academic Search

A theoretical and experimental investigation of the transient thermal characteristics of a phase-change thermal energy storage (TES) unit using spherical capsules is presented. A simulation program that considers rigorously transient aspects of both the surrounding heat transfer fluid and the phase change material (PCM) packed inside the spherical capsule is developed. The overall thermal response of this TES unit is

T. SAITOH; K. HIROSE

1986-01-01

334

Performance model for parabolic trough solar thermal power plants with thermal storage: Comparison to operating plant data  

Microsoft Academic Search

This paper describes a simulation model that reproduces the performance of parabolic trough solar thermal power plants with a thermal storage system. The aim of this model is to facilitate the prediction of the electricity output of these plants during the various stages of their planning, design, construction and operation. Model results for a 50MWe power plant are presented and

Isabel Llorente García; José Luis Álvarez; Daniel Blanco

2011-01-01

335

Thermal performance of a simple design solar air heater with built-in thermal energy storage system  

Microsoft Academic Search

The thermal performance of a simple design solar air heater is presented. The conventional flat plate absorber is replaced by a set of tubes filled with a thermal energy storage material. The proposed integrated system heat transfer area and heat transfer coefficient are increased, and the heat loss is reduced. Based on a simple transient analysis, explicit expressions for the

Hassan E. S. Fath

1995-01-01

336

Multi-Objective Optimization of Residential Building Roof Layer Thickness for Minimization of Heat Entering the Room Using FEM and Grey Relational Analysis  

NASA Astrophysics Data System (ADS)

In this work, a multi objective optimization on roof layer thickness has been carried out through Taguchi based grey relational analysis technique. Conventional type of residential building roof was changed by a modified pattern of roof having layers namely concrete, phase change material, wood wool and weathering tile and its performance on heat insulation have been studied. In this study, the optimum thickness of roof layers was determined for minimum heat gain through roof by grey relational analysis technique. The thickness of various roof layers were considered as control parameters and varied through five levels of values. For this objective, Taghuchi's L25 orthogonal array has been employed and the performance on heat insulation was studied through finite element analysis (FEA) technique. The FEA simulation on heat transfer across the roof has also been validated with the experimental results and found that it is having a good agreement. The optimized roof reduces the heat gain and temperature by 30 % and 3 °C respectively in comparison with the conventional type of roof. Also from this study, it was identified that the wood wool is the most predominant roof layer that controls the heat gain into the room.

Prakash, D.; Ravikumar, P.

2014-01-01

337

Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions  

PubMed Central

Background Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. Methodology/Principal Findings We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Conclusions/Significance Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green roof ecosystems. PMID:20300196

Lundholm, Jeremy; MacIvor, J. Scott; MacDougall, Zachary; Ranalli, Melissa

2010-01-01

338

Design considerations for retractable-roof stadia  

E-print Network

As existing open-air or fully enclosed stadia are reaching their life expectancies, cities are choosing to replace them with structures with moving roofs. This kind of facility provides protection from weather for spectators, ...

Frazer, Andrew H., 1981-

2005-01-01

339

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2011 CFR

...any other purpose that could affect the tension of the bolt. Hanging...bolts are permitted. (8) Angle compensating devices shall be used to compensate for the angle when tensioned roof bolts are installed at angles greater than 5 degrees...

2011-07-01

340

Thermal performance of a multi-evaporator loop heat pipe with thermal masses and thermal electrical coolers  

NASA Technical Reports Server (NTRS)

This paper describes thermal performance of a loop heat pipe (LHP) with two evaporators and two condensers in ambient testing. Each evaporator has an outer diameter of 15mm and a length of 76mm, and has an integral compensation chamber (CC). An aluminum mass of 500 grams is attached to each evaporator to simulate the instrument mass. A thermal electric cooler (TEC) is installed on each CC to provide heating as well as cooling for CC temperature control. A flow regulator is installed in the condenser section to prevent vapor from going back to the evaporators in the event that one of condenser is fully utilized. Ammonia was used ad the working fluid. Tests conducted included start-up, power cycle, heat load sharing, sink temperature cycle, operating temperature control with TECs, and capillary limit tests. Experimental data showed that the loop could start with a heat load of less than 1OW even with added thermal masses. The loop operated stably with even and uneven evaporator heat loads, and even and uneven condenser sink temperatures. The operating temperature could be controlled within +/-0.5K of the set point temperature using either or both TECs, and the required TEC control heater power was less than 2W under most test conditions. Heat load sharing between the two evaporators was also successfully demonstrated. The loop had a heat transport capability of 120W to 140W, and could recover from a dry-out when the heat load was reduced. The 500-gram aluminum mass on each evaporator had a negligible effect on the loop operation. Existing LHPs servicing the orbiting spacecraft have a single evaporator with an outer diameter of about 25mm. Important performance characteristics demonstrated by this LHP included: 1) Operation of an LHP with 15mm diameter evaporators; 2) Robustness and reliability of an LHP with multiple evaporators and multiple condensers under various test conditions; 3) Heat load sharing among LHP evaporators; 4) Effectiveness of TECs in controlling the LHP operating temperature; and 5) Effectiveness of the flow regulator in preventing vapor from going back the evaporators.

Ku, Jentung; Ottenstein, Laura; Birur, Gajanana

2004-01-01

341

Roof Coating Procedures and Their Productivity Gains  

E-print Network

Roof Coating Procedures and their Productivity Gains John Bonaby and Dr. Diane Schaub, University of Florida As building envelope improvements are realized in organizations as ways to insulate businesses from high energy costs, the relative... procedures coupled with this experiment include an extensive assessment of obtainable literature and existing studies along with consultation from noted authorities in similar fields. In addition, a range of commercially available roof coatings...

Bonaby, J.; Schaub, D.

2006-01-01

342

Experimental study of a roof solar collector towards the natural ventilation of new houses  

Microsoft Academic Search

The paper discusses the possibility of offering thermal comfort in new housing built in European style and situated in a hot and humid climate, without inducing mechanical energy cost, by means of a constructive element: the Roof Solar Collector (RSC). With this RSC it is possible, on the one hand, to minimize the fraction of the solar flux absorbed by

Joseph Khedari; Jongjit Hirunlabh; Tika Bunnag

1997-01-01

343

Determination of thermal performance characteristics of modular passive solar storage walls. Final report  

Microsoft Academic Search

A conceptual study of testing procedures to determine thermal performance characteristics of Trombe-wall-type passive solar storage wall systems has been performed. In the study, a finite-difference thermal model of a passive solar storage wall in a test facility was used to predict the wall thermal performance in a particular climatic location. The simulated test results were used in a multiple

W. Kennish; M. McCabe

1980-01-01

344

Sensor nanofabrication, performance, and conduction mechanisms in scanning thermal microscopy  

Microsoft Academic Search

A new nanofabrication procedure has been developed for making thermocouple probes for high-resolution scanning thermal microscopy. Thermocouple junctions were placed at the end of SiNâ cantilever probe tips and were typically 100â500 nm in diameter. Cantilever bending due to thermal expansion mismatch was minimized for AuâNi, AuâPt, and AuâPd thermocouples, by carefully choosing thermal probe materials, film thicknesses, and deposition

K. Luo; Z. Shi; J. Varesi; A. Majumdar

1997-01-01

345

Comparative thermal performance of direct gain, Trombe, and sunspace walls  

NASA Astrophysics Data System (ADS)

The natural thermal storage features of the Brookhaven superinsulated house were analyzed and verified. These include the Trombe and sunspace passive-solar-collection walls and the superinsulated south-facing wall. The thermal contributions of each system were demonstrated. Several thermal characteristic factors, in relation to each design for the hourly and daily period, were assessed. Further, the interior temperature fluctuations and the reductions in the required auxiliary energy with regard to incorporated passive designs were evaluated.

Ghaffari, H. T.; Jones, R. F.

1981-09-01

346

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) two more sets of field tests have been conducted in an underground coal mine, (2) optimization studies of the control parameters have been conducted, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (3) about 97% of the development work for the roof geology mapping program, MRGIS, has completed, (4) A special version of the geology mapping program for a limestone mine has been developed. The field test for the software and hardware has been successfully finished.

Syd S. Peng

2004-09-15

347

EVALUATION OF ROOF BOLTING REQUIREMENTS BASED ON IN-MINE ROOF BOLTER DRILLING  

SciTech Connect

A one-year non-cost extension has been granted for this project. In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) laboratory tests have been conducted, (2) with the added trendline analysis method, the accuracy of the data interpretation methodology will be improved and the interfaces and voids can be more reliably detected, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (3) about 80% of the development work for the roof geology mapping program, MRGIS, has completed and a special version of the program is in the field testing stage.

Syd S. Peng

2004-04-15

348

Hydrogen recombination kinetics and nuclear thermal rocket performance prediction  

NASA Astrophysics Data System (ADS)

The rate constants for the hydrogen three-body collisional recombination reaction with atomic and molecular hydrogen acting as third bodies have been determined by numerous investigators during the past 30 yr, but these rates exhibit significant scatter. The discrepancies in the rate constants determined by different investigators are as great as two orders of magnitude in the temperature range of interest for nuclear thermal rocket (NTR) operation, namely, 2000-3300 K. The impact of this scatter on our ability to predict the specific impulse (I(sub sp)) delivered by a 30-klbf NTR has been determined for chamber pressures and temperatures from, respectively, 20-1000 psia and 2700-3300 K. The variation in I(sub sp) produced by using the different rate constants is as great as 10%, or 100 s. This variation also obscures the influence of chamber pressure on I(sub sp); using fast kinetics, low pressures yield significantly improved performance, while using slow or nominal kinetics, the pressure dependence of I(sub sp) is negligible. Because the flow composition freezes at very small area ratios, optimization of the nozzle contour in the near-throat region maximizes recombination. Vibrational relaxation is found to produce negligible losses in I(sub sp).

Wetzel, Kyle K.; Solomon, Wayne C.

1994-07-01

349

Performance of solar thermal systems with liquid metal MHD conversion  

NASA Astrophysics Data System (ADS)

Liquid metal magnetohydrodynamic conversion (LMMHD) is found to be compatible with concentrating solar receivers employing a liquid metal as a heat transfer medium and offers significant increases in the system thermal efficiency over the 33% considered attainable with conventional turbo-machinery. There are two candidate liquid metals - sodium and lithium. With sodium at a temperature of 1150 F (922 K), the maximum calculated efficiency is 39.5% while with lithium at 1400 F (1033 K) a peak efficiency for 46.5% is predicted. Up to two percentage points may be added by temperature increase and/or parameter limit relaxation in the sodium case. The sodium steam heat exchanger is eliminated in liquid metal systems. Where LMMHD systems employ the same working fluid as the solar receiver, no recirculating pump is required as pumping power is provided directly by the cycle. For sodium, coupling with either a gas turbine or a steam turbine is beneficial and provides similar performance. With lithium, the gas turbine cycle is clearly superior.

Pierson, E. S.; Jackson, W. D.; Berry, G.; Petrick, M.; Dennis, C.

1984-06-01

350

Performance study of a thermal-envelope house: Phase II. Cooling performance. Final report  

SciTech Connect

The thermal envelope house is shown to perform much better than conventional houses without mechanical refrigeration and better than one would expect from most passively cooled houses in the hot-humid climate of Georgia. Peak temperatures inside the house were 8 to 15/sup 0/F below peak ambient temperatures. Peak inside temperature measured during the test period was 80/sup 0/F with an outside ambient peak of 93/sup 0/F. Air flow rates within the envelope were less than 1 ft/sec even when the attic fan was operating. The earth cooling tubes provided noticeable sensible cooling to the house. Exit temperatures from the cooling tubes were between 72 to 76/sup 0/F, depending upon the air velocity through the tubes. The thermal chimney performed poorly as an air mover, especially when used to induce flow through the earth cooling tubes. The performance of the earth cooling tube could be improved by using the attic fan to increase the air flow through the cooling tubes and to insure it flowed in the cooling tube, through the envelope and out the thermal chimney. Being an exhaust fan, the attic fan created a negative pressure in the house. While this increased air flow through the cooling tubes, it also increased air infiltration through the building shell, thus increasing load. The humidity level within the living space remains relatively high year-round due to low rates of air infiltration and water vapor transmission through the building skin. The problem is aggravated during the summer by the introduction of cool moist air from the cooling tubes to the envelope and frequently to the inner space. While the cooling tubes are able to reduce the sensible load, and they are incapable of significantly reducing humidity or latent loads. This results in relatively comfortable air temperatures but uncomfortable humidities within the living space.

Akridge, J. M.; Benton, C. C.

1981-01-01

351

Evaluation of green roof as green technology for urban stormwater quantity and quality controls  

NASA Astrophysics Data System (ADS)

Promoting green design, construction, reconstruction and operation of buildings has never been more critical than now due to the ever increasing greenhouse gas emissions and rapid urbanizations that are fuelling climate change more quickly. Driven by environmental needs, Green Building Index (GBI) was founded in Malaysia to drive initiative to lead the property industry towards becoming more environment-friendly. Green roof system is one of the assessment criteria of this rating system which is under category of sustainable site planning and management. An extensive green roof was constructed in Humid Tropics Center (HTC) Kuala Lumpur as one of the components for Stormwater Management Ecohydrology (SME) in order to obtain scientific data of the system. This paper evaluates the performance of extensive green roof at Humid Tropics Center with respect to urban heat island mitigation and stormwater quantity and quality controls. Findings indicate that there was a reduction of around 1.5°C for indoor temperature of the building after installation of green roof. Simulations showed that the peak discharge was reduced up to 24% relative to impervious brown roof. The results show an increment of pH and high concentration of phosphate for the runoff generated from the green roof and the runoff water quality ranged between class I and II under INWQS.

Kok, K. H.; Sidek, L. M.; Abidin, M. R. Z.; Basri, H.; Muda, Z. C.; Beddu, S.

2013-06-01

352

The hydrological behaviour of extensive and intensive green roofs in a dry climate.  

PubMed

This paper presents the results of a hydrological investigation of four medium scale green roofs that were set up at the University of South Australia. In this study, the potential of green roofs as a source control device was investigated over a 2 year period using four medium size green roof beds comprised of two growth media types and two media depths. During the term of this study, 226 rainfall events were recorded and these were representative of the Adelaide climate. In general, there were no statistically significant differences between the rainfall and runoff parameters for the intensive and extensive beds except for peak attenuation and peak runoff delay, for which higher values were recorded in the intensive beds. Longer dry periods generally resulted in higher retention coefficients and higher retention was also recorded in warmer seasons. The average retention coefficient for intensive systems (89%) was higher than for extensive systems (74%). It was shown that rainfall depth, intensity, duration and also average dry weather period between events can change the retention performance and runoff volume of the green roofs. Comparison of green and simulated conventional roofs indicated that the former were able to mitigate the peak of runoff and could delay the start of runoff. These characteristics are important for most source control measures. The recorded rainfall and runoff data displayed a non-linear relationship. Also, the results indicated that continuous time series modelling would be a more appropriate technique than using peak rainfall intensity methods for green roof design and simulation. PMID:25194906

Razzaghmanesh, M; Beecham, S

2014-11-15

353

Green roofs for a drier world: effects of hydrogel amendment on substrate and plant water status.  

PubMed

Climate features of the Mediterranean area make plant survival over green roofs challenging, thus calling for research work to improve water holding capacities of green roof systems. We assessed the effects of polymer hydrogel amendment on the water holding capacity of a green roof substrate, as well as on water status and growth of Salvia officinalis. Plants were grown in green roof experimental modules containing 8 cm or 12 cm deep substrate (control) or substrate mixed with hydrogel at two different concentrations: 0.3 or 0.6%. Hydrogel significantly increased the substrate's water content at saturation, as well as water available to vegetation. Plants grown in 8 cm deep substrate mixed with 0.6% of hydrogel showed the best performance in terms of water status and membrane integrity under drought stress, associated to the lowest above-ground biomass. Our results provide experimental evidence that polymer hydrogel amendments enhance water supply to vegetation at the establishment phase of a green roof. In particular, the water status of plants is most effectively improved when reduced substrate depths are used to limit the biomass accumulation during early growth stages. A significant loss of water holding capacity of substrate-hydrogel blends was observed after 5 months from establishment of the experimental modules. We suggest that cross-optimization of physical-chemical characteristics of hydrogels and green roof substrates is needed to improve long term effectiveness of polymer-hydrogel blends. PMID:24867709

Savi, Tadeja; Marin, Maria; Boldrin, David; Incerti, Guido; Andri, Sergio; Nardini, Andrea

2014-08-15

354

Performance assessment of low pressure nuclear thermal propulsion  

NASA Technical Reports Server (NTRS)

An increase in Isp for nuclear thermal propulsion systems is desirable for reducing the propellant requirements and cost of future applications, such as the Mars Transfer Vehicle. Several previous design studies have suggested that the Isp could be increased substantially with hydrogen dissociation/recombination. Hydrogen molecules (H2), at high temperatures and low pressures, will dissociate to monatomic hydrogen (H). The reverse process (i.e., formation of H2 from H) is exothermic. The exothermic energy in a nozzle increases the kinetic energy and therefore, increases the Isp. The low pressure nuclear thermal propulsion system (LPNTP) system is expected to maximize the hydrogen dissociation/recombination and Isp by operating at high chamber temperatures and low chamber pressures. The process involves hydrogen flow through a high temperature, low pressure fission reactor, and out a nozzle. The high temperature (approximately 3000 K) of the hydrogen in the reactor is limited by the temperature limits of the reactor material. The minimum chamber pressure is about 1 atm because lower pressures decrease the engines thrust to weight ratio below acceptable limits. This study assumes that hydrogen leaves the reactor and enters the nozzle at the 3000 K equilibrium dissociation level. Hydrogen dissociation in the reactor does not affect LPNTP performance like dissociation in traditional chemical propulsion systems, because energy from the reactor resupplies energy lost due to hydrogen dissociation. Recombination takes place in the nozzle due primarily to a drop in temperature as the Mach number increases. However, as the Mach number increases beyond the nozzle throat, the static pressure and density of the flow decreases and minimizes the recombination. The ideal LPNTP Isp at 3000 K and 10 psia is 1160 seconds due to the added energy from fast recombination rates. The actual Isp depends on the finite kinetic reaction rates which affect the amount of monatomic hydrogen recombination before the flow exits the nozzle. A LPNTP system has other technical issues (e.g. flow instability and two-phase flow) besides hydrogen dissociation/recombination which affect the systems practicality. In this study, only the effects of hydrogen dissociation/recombination are examined.

Gerrish, Harrold P., Jr.; Doughty, Glen E.

1993-01-01

355

Modeling of target thermal structure effects on the performance of staring IR seekers  

Microsoft Academic Search

The target thermal structure is playing a stronger role in modeling the performance of autonomous IR seekers to acquire and track targets. The impact of the target thermal structure on seeker and sensor acquisition has been previously reported. In this paper, the impact of the target's thermal structure on the acquisition and tracking capability of autonomous imaging IR seekers using

Eric J. Borg

1994-01-01

356

Performance Evaluation of Face Recognition using Visual and Thermal Imagery with Advanced Correlation Filters  

Microsoft Academic Search

This paper presents the face recognition performance evaluation using visual and thermal infrared (IR) face images with correlation filter methods. New correlation filter designs have shown to be distortion invariant and the advantages of using thermal IR images are due to their invariance to visible illumination variations. A combined use of thermal IR image data and correlation filters makes a

Jingu Heo; Marios Savvides; B. V. K. Vijayakumar

2005-01-01

357

Investigation of methods to predict thermal stratification and its effect on solar energy system performance  

Microsoft Academic Search

This report describes a study to identify characteristics which induce thermal stratification in liquid thermal storage, and to evaluate solar energy system performance as a function of the degree of stratification. It was determined that for efficient use of thermal stratification it was necessary to (1) introduce hot fluid at the top of the liquid storage tank to add cold

B. J. Sliwinski

1980-01-01

358

Functional outcome after acetabular revision with roof reinforcement rings  

PubMed Central

Objective To evaluate the role for potential predictors of functional outcome after acetabular arthroplasty and to assess the results of revision with the use of a roof reinforcement ring. Design A retrospective case series. Setting A tertiary-care referral centre. Patients Twenty-four patients (average age 72.7 years) who had undergone acetabular revision with a roof reinforcement ring were followed up for an average of 2.8 years. Interventions Revision acetabular arthroplasty was performed using either the Mueller or Burch–Schneider roof reinforcement ring, bone grafting and a cemented polyethylene cup. Outcome measures A modified Harris hip score (range of motion omitted), the SF-36 health survey and the Western Ontario McMaster (WOMAC) osteoarthritis index measured outcome. Multivariate analysis was used to determine the effects of certain clinical factors (age, sex, time to revision from previous hip operation and number of previous revisions) on outcome. Results Patients reported disability both on hip-specific and general health measures. The time to revision from previous operation positively correlated with SF-36 mental component scores (p = 0.003), WOMAC function (p = 0.04) and WOMAC pain (p = 0.03). Age, gender and number of past revisions did not affect outcome. Conclusions Patients who undergo acetabular revision with a roof ring will continue to have some disability in the first 3 years after the procedure. A greater time between the previous operation and the revision operation is associated with a better outcome. Patients’ expectations of postoperative results should be realistic in the face of a challenging reconstructive procedure. PMID:10948688

Jain, Rina; Schemitsch, Emil H.; Waddell, James P.

2000-01-01

359

Predicting performance of coatings under thermal insulation at high temperatures  

SciTech Connect

A probe was designed to evaluate coatings used under thermal insulation for temperatures of 30 to 150 C. This article describes the results obtained with various combinations of coatings (aluminum silicone, inorganic zinc, and aluminum metallizing) and thermal insulators (mineral wool, fiber glass, and calcium silicate), which were recommended in NACE Publication 6H189.

Lasarte, C. (Pequiven, S.A., Maracaibo (Venezuela). Petroquimica de Venezuela); Rincon, O.T. De; Montiel, A. (Univ. del Zulia, Maracaibo (Venezuela). Centro de Estudios de Corrosion)

1994-10-01

360

Mechanisms governing the performance of thermal barrier coatings  

Microsoft Academic Search

Thermal barrier coatings (TBCs) are now used on hot section components in most commercial turbine engines. They are used to enhance the temperature differential between the gas and the underlying metal surfaces. They comprise several layers designed to simultaneously provide thermal and oxidation protection. They have microstructures which afford sufficient strain tolerance that they remain attached despite severe thermomechanical cycling.

P. K. Wright; A. G. Evans

1999-01-01

361

Improving the thermal performance of coaxial borehole heat exchangers  

Microsoft Academic Search

Borehole heat exchangers are the fundamental component of ground coupled heat pumps, which are now widely employed for energy saving in building heating and cooling. The improvement of the thermal efficiency of Coaxial Borehole Heat Exchangers (CBHEs) is pursued in this paper by investigating the effects of thermal short-circuiting and of flow rate, as well as of the constituent materials

E. Zanchini; S. Lazzari; A. Priarone

2010-01-01

362

The case for using a sacrificial layer of absorbent insulation in the design of flat and low-sloped roofing  

NASA Astrophysics Data System (ADS)

Beginning about twenty-five years ago, there was a marked increase in the number of single-ply membrane roof designs used to cover and waterproof flat and low-sloped building roofs. Over the past ten years, there has been a substantial increase in the number of installations of white and more reflective single-ply roof systems, mostly using high density cellular foam insulation in the substrate for insulation. A major factor in the increase in the popularity of these highly insulated and more reflective roof systems is the fact that many governments began offering incentives for building owners to use reflective coverings and better insulated roofs. Now, owing to the energy efficient requirements for the design and construction of new buildings put forth in ASHRAE Standard 90.1, "Energy Standard for Buildings Except Low-Rise Residential Buildings" and the world's apparent desire to be "green" (or at least appear to be), more and more roof designs will include these reflective single-ply membranes, which use the cellular foam insulation boards to meet these requirements. Using a lower density traditional insulation will mean that the roof will have to be very thick to comply, increasing the costs of installation. High density cellular foams do not absorb water until time, vapor pressure drive, UV and thermal shock break down the foam and it becomes more absorbent. This could be 5-7 years or longer, depending on the roof construction and other factors. This means that any water that enters the roof through a breach (leak) in the membrane goes straight into the building. This is not a good consequence since the failure mode of any roof is water entering the building. Keeping the water out of the building is the purpose of the waterproofing layer. This paper reviews the techniques of moisture testing on building roofs and infrared (IR) thermography, and puts forth the idea and reasoning behind having a sacrificial layer of very absorbent insulation installed in every flat and low-sloped roof so that when a breach occurs, it can easily be found, documented and repaired during an annual infrared inspection; as IR is an effective predictive maintenance technique and condition monitoring best practice for roof maintenance.

Stockton, Gregory R.

2013-05-01

363

Green Roofs for a Green Town: Possibilities of Green Roof Implementation in the Town of Normal  

Microsoft Academic Search

Green roofs have been growing in popularity throughout the world. Scientists have been studying them since the 1980’s. This research project reviews the literature regarding both the benefits and barriers to green roof construction and management. Policies around the nation are then examined and analyzed. Suggestions are made regarding possible additions to the local Stormwater Management Policy that would emphasize

Sihau Lindsey

2008-01-01

364

Automatic Roof Outlines Reconstruction from Photogrammetric Dsm  

NASA Astrophysics Data System (ADS)

The extraction of geometric and semantic information from image and range data is one of the main research topics. Between the different geomatics products, 3D city models have shown to be a valid instrument for several applications. As a consequence, the interest for automated solutions able to speed up and reduce the costs for 3D model generation is greatly increased. Image matching techniques can nowadays provide for dense and reliable point clouds, practically comparable to LiDAR ones in terms of accuracy and completeness. In this paper a methodology for the geometric reconstruction of roof outlines (eaves, ridges and pitches) from aerial images is presented. The approach keeps in count the fact the usually photogrammetrically derived point clouds and DSMs are more noisy with respect to LiDAR data. A data driven approach is used in order to keep the maximum flexibility and to achieve satisfying reconstructions with different typologies of buildings. Some tests and examples are reported showing the suitability of photogrammetric DSM for this topic and the performances of the developed algorithm in different operative conditions.

Nex, F.; Remondino, F.

2012-07-01

365

Thermal Performance of a Multi-Evaporator Loop Heat Pipe with Thermal Masses and Thermoelectric Coolers  

NASA Technical Reports Server (NTRS)

This paper describes thermal performance of a loop heat pipe (LHP) with two evaporators and two condensers in ambient testing. Each evaporator has an outer diameter of 15mm and a length of 76mm, and has an integral compensation chamber (CC). An aluminum mass of 500 grams is attached to each evaporator to simulate the instrument mass. A thermoelectric cooler (TEC) is installed on each CC to provide heating as well as cooling for CC temperature control. A flow regulator is installed in the condenser section to prevent vapor from going back to the evaporators in the event that one of the condensers is fully utilized. Ammonia was used as the working fluid. Tests conducted included start-up, power cycle, heat load sharing, sink temperature cycle, operating temperature control with TECs, and capillary limit tests. Experimental data showed that the loop could start with a heat load of less than 10W even with added thermal masses. The loop operated stably with even and uneven evaporator heat loads, and even and uneven condenser sink temperatures. The operating temperature could be controlled within +/- 0.5K of the set point temperature using either or both TECs, and the required TEC control heater power was less than 2W under most test conditions. Heat load sharing between the two evaporators was also successfully demonstrated. The loop had a heat transport capability of 120W to 140W, and could recover from a dry-out when the heat load was reduced. The 500-gram aluminum mass on each evaporator had a negligible effect on the loop operation. Existing LHPs servicing orbiting spacecraft have a single evaporator with an outer diameter of about 25mm. Important performance characteristics demonstrated by this LHP included: 1) Operation of an LHP with 15mm diameter evaporators; 2) Robustness and reliability of an LHP with multiple evaporators and multiple condensers under various test conditions; 3) Heat load sharing among LHP evaporators; 4) Effectiveness of TECs in controlling the LHP operating temperature; and 5 ) Effectiveness of the flow regulator in preventing vapor from going back the evaporators.

Ku, Jen-Tung; Ottenstein, Laura; Birur, Gajanana

2004-01-01

366

Comparative thermal performance of direct gain, Trombe, and sunspace walls  

SciTech Connect

The natural thermal storage features of the Brookhaven superinsulated house are analyzed and verified. These include the Trombe and sunspace passive-solar-collection walls and the superinsulated south-facing wall, denoted herein as the direct-gain wall. The thermal contributions of each system on the basis of the in-field empirical data are demonstrated. Several thermal characteristic factors, in relation to each design for the hourly and daily period, are assessed. Further, the interior temperature fluctuations and the reductions in the required auxiliary energy with regard to incorporated passive designs are evaluated.

Ghaffari, H.T.; Jones, R.F.

1981-01-01

367

Contrasted thermal preferences translate into divergences in habitat use and realized performance in two  

E-print Network

ectotherm; thermoregulatory strategy; cost- benefit model of thermoregulation; microhabitat selection-7998.2011.00802.x Abstract Temperature influences ectotherm fitness by affecting physiological performance Ectotherms depend on environmental thermal conditions to optimize physiological performances (Huey

Blouin-Demers, Gabriel

368

Radiative transfer and thermal performance levels in foam insulation boardstocks  

E-print Network

The validity of predictive models for the thermal conductivity of foam insulation is established based on the fundamental geometry of the closed-cell foam. The extinction coefficient is experimentally and theoretically ...

Moreno, John David

1991-01-01

369

Thermal performance of a photographic laboratory process: Solar Hot Water System  

NASA Technical Reports Server (NTRS)

The thermal performance of a solar process hot water system is described. The system was designed to supply 22,000 liters (5,500 gallons) per day of 66 C (150 F) process water for photographic processing. The 328 sq m (3,528 sq. ft.) solar field has supplied 58% of the thermal energy for the system. Techniques used for analyzing various thermal values are given. Load and performance factors and the resulting solar contribution are discussed.

Walker, J. A.; Jensen, R. N.

1982-01-01

370

The effect of roof strength on reducing occupant injury in rollovers.  

PubMed

Roof crush occurs and potentially contributes to serious or fatal occupant injury in 26% of rollovers. It is likely that glazing retention is related to the degree of roof crush experienced in rollover accidents. Occupant ejection (including partial ejection) is the leading cause of death and injury in rollover accidents. In fatal passenger car accidents involving ejection, 34% were ejected through the side windows. Side window glass retention during a rollover is likely to significantly reduce occupant ejections. The inverted drop test methodology is a test procedure to evaluate the structural integrity of roofs under loadings similar to those seen in real world rollovers. Recent testing on many different vehicle types indicates that damage consistent with field rollover accidents can be achieved through inverted drop testing at very small drop heights. Drop test comparisons were performed on 16 pairs of vehicles representing a large spectrum of vehicle types. Each vehicle pair includes a production vehicle and a vehicle with a reinforced roof structure dropped under the same test conditions. This paper offers several examples of post-production reinforcements to roof structures that significantly increase the crush resistance of the roof as measured by inverted drop tests. These modifications were implemented with minimal impact on vehicle styling, interior space and visual clearances. The results of these modifications indicate that roof crush can be mitigated by nearly an order of magnitude, as roof crush was reduced by 44-91% with only a 1-2.3% increase in vehicle weight. Additionally, this paper analyzes the glazing breakage patterns in the moveable tempered side windows on the side adjacent to the vehicle impact point in the inverted drop tests. A comparison is made between the production vehicles and the reinforced vehicles in order to determine if the amount roof crush is related to glazing integrity in the side windows. Lastly, two drop test pairs, performed with Hybrid III test dummies, indicates that the reduction of roof crush resulted in a direct reduction in neck loading and therefore an increase in occupant protection. PMID:15850089

Herbst, Brian; Forrest, Steve; Orton, Tia; Meyer, Steven E; Sances, Anthony; Kumaresan, Srirangam

2005-01-01

371

Thermal Performance of Idealized Double Windows, Unvented. Research Paper No. 223.  

ERIC Educational Resources Information Center

The testing plans, procedures, and results of an experiment are revealed concerning the thermal performance and variable factors of unvented double windows, their heat transmission and inner surface temperature. Data are given to help improve the design and development of standards for the thermal performance of windows. Building humidity, window…

Christensen, G.; And Others

372

Comparison of Thermal Performances Predicted and Experimental of Solar Air Collector  

Microsoft Academic Search

In this study, thermal performance of solar air collector system which was experimentally constructed was obtained for different operating conditions. Experiments were conducted under Turkey\\/Mersin climatic conditions. Then, Neural Network (NN) models have been developed for the prediction the thermal performance of solar air collectors. Experimental data were used for training and testing of the networks. The inputs of the

Arzu Sencan; Gokhan Ozdemir

2007-01-01

373

The Effect of Windbreak Walls on the Thermal Performance of Natural Draft Dry Cooling Towers  

Microsoft Academic Search

A three-dimensional study using the standard k-? turbulence model to simulate airflow in and around a natural draft dry cooling tower (NDDCT) has been conducted using a general-purpose CFD code. This investigation considered the location and the porosity of windbreak walls' structure on the NDDCT thermal performance. In addition, the effect of the windbreak walls on the thermal performance of

Rafat Al-Waked; Masud Behnia

2005-01-01

374

Thermal performance of integrated collector storage solar water heater with corrugated absorber surface  

Microsoft Academic Search

An investigation is reported of the thermal performance of an integrated solar water heater with a corrugated absorber surface. The thermal performance of the rectangular collector\\/storage solar water heater depends significantly on the heat transfer rate between the absorber surface and the water, and on the amount of solar radiation incident on the absorber surface. In this investigation, the surface

Rakesh Kumar; Marc A. Rosen

2010-01-01

375

Effect of thermal trap on the performance of an underground SSP water heater  

Microsoft Academic Search

Sodha et al have studied the effect of thermal trap material on the performance of an underground water heater which consists of a network of pipes buried in the ground. The water is allow to flow through pipes for a complete cycle i.e. 24 hrs. They concluded that the use of thermal trap material enhances the performance of ground collector.

Tiwari

1983-01-01

376

Thermal performance parameters estimation of hot box type solar cooker by using artificial neural network  

Microsoft Academic Search

Work to date has shown that Artificial Neural Network (ANN) has not been used for predicting thermal performance parameters of a solar cooker. The objective of this study is to predict thermal performance parameters such as absorber plate, enclosure air and pot water temperatures of the experimentally investigated box type solar cooker by using the ANN. Data set is obtained

Hüseyin Kurt; Kemal Atik; Mehmet Özkaymak; Ziyaddin Recebli

2008-01-01

377

The application of simulation modeling to the cost and performance ranking of solar thermal power plants  

Microsoft Academic Search

Small solar thermal power systems (up to 10 MWe in size) were tested. The solar thermal power plant ranking study was performed to aid in experiment activity and support decisions for the selection of the most appropriate technological approach. The cost and performance were determined for insolation conditions by utilizing the Solar Energy Simulation computer code (SESII). This model optimizes

L. S. Rosenberg; W. R. Revere; M. K. Selcuk

1981-01-01

378

ATS-6 engineering performance report. Volume:Program and systems summaries: Mechanical and thermal details  

NASA Technical Reports Server (NTRS)

The overall mission and spacecraft systems, testing, and operations are summarized. The mechanical subsystems are reviewed, encompassing mechanical design requirements; separation and deployment mechanisms; design and performance evaluation; and the television camera reflector monitor. Thermal control and contamination are discussed in terms of thermal control subsystems, design validation, subsystems performance, the advanced flight experiment, and the quartz-crystal microbalance contamination monitor.

Wales, R. O. (editor)

1981-01-01

379

Performances of the Planck-HFI cryogenic thermal control system  

NASA Astrophysics Data System (ADS)

The core of the High Frequency Instrument (HFI) on-board the Planck satellite consists of 52 bolometric detectors cooled at 0.1 Kelvin. In order to achieve such a low temperature, the HFI cryogenic architecture consists in several stages cooled using different active coolers. These generate weak thermal fluctuations on the HFI thermal stages. Without a dedicated thermal control system these fluctuations could produce unwanted systematic effects, altering the scientific data. The HFI thermal architecture allows to minimise these systematic effects, thanks to passive and active control systems described in this paper. The passive and active systems are used to damp the high and low frequency fluctuations respectively. The last results regarding the tests of the HFI passive and active thermal control systems are presented here. The thermal transfer functions measurement between active coolers and HFI cryogenic stages will be presented first. Then the stability of the temperatures obtained on the various cryogenic stages with PID regulations systems will be checked through analysis of their power spectrum density.

Leroy, Christophe; Arondel, Antoine; Bernard, Jean-Philippe; Carfantan, Hervé; Dumesnil, Cydalise; Fourmond, Jean-Jacques; Guyot, Guy; Lamarre, Jean-Michel; Pajot, François; Piat, Michel; Puget, Jean-Loup; Trouilhet, Jean-Francois; Varesi, Sylvain

2006-06-01

380

Biometric Consortium Conference (BC2003), Crystal City, VA Performance Comparison of Visual and Thermal Signatures for Face Recognition  

E-print Network

that thermal face recognition using linear discriminant analysis (LDA) yielded good performances rates for visual images. Thermal image alignment was performed in two ways and evaluations conductedBiometric Consortium Conference (BC2003), Crystal City, VA Performance Comparison of Visual

Abidi, Mongi A.

381

Determination of thermal performance characteristics of modular passive solar storage walls  

SciTech Connect

A conceptual study of testing procedures to determine thermal performance characteristics of Trombe-Wall type passive solar storage wall systems has been performed. In the study, a finite-difference thermal model of a passive solar storage wall in a test facility was used to predict the wall thermal performance in a particular climatic location. The simulated test results were used in a multiple regression analysis to characterize the thermal performance of test wall. These characteristics were then used in a simplified calculation procedure to predict the thermal performance of the solar storage wall in different climatic regions. A comparison of these predictions with detailed computer simulation results for these other climatic regions show that the test procedure and data reduction technique provides a simple method of characterizing the passive solar storage wall and has potential wide scale applications for modular passive components.

Kennish, W.J. (TPI, Inc., Beltsville, MD); Ahmed, M.; McCabe, M.; McKinstry, M.

1980-01-01

382

Performance Testing of Thermal Interface Filler Materials in a Bolted Aluminum Interface Under Thermal/Vacuum Conditions  

NASA Technical Reports Server (NTRS)

A thermal interface material is one of the many tools often used as part of the thermal control scheme for space-based applications. Historically, at Marshall Space Flight Center, CHO-THERM 1671 has primarily been used for applications where an interface material was deemed necessary. However, numerous alternatives have come on the market in recent years. It was decided that a number of these materials should be tested against each other to see if there were better performing alternatives. The tests were done strictly to compare the thermal performance of the materials relative to each other under repeatable conditions and do not take into consideration other design issues, such as off-gassing, electrical conduction, isolation, etc. The purpose of this Technical Memorandum is to detail the materials tested, test apparatus, procedures, and results of these tests. The results show that there are a number of better performing alternatives now available.

Glasgow, S. D.; Kittredge, K. B.

2003-01-01

383

Preparation and performance of thermal insulation energy saving coating materials for exterior wall.  

PubMed

Nano zinc oxide with a high refractive index has good thermal reflection performance, hollow glass microspheres have good thermal reflection and insulation performance, and sepiolite nanofibers with many nanostructural pores have good thermal insulation performance. The dispensability of nano zinc oxide in coating materials was improved by optimizing surface silane coupling agent modification process, leading to the good thermal reflection performance. The thermal insulation performance was improved by hollow glass microspheres and sepiolite nanofibers. On this basis, the thermal insulation coating materials were prepared by exploring the effect of amount, complex mode, and other factors of the above three kinds of functional fillers on the thermal reflection and insulation performance of coating materials. The results showed that the surface modification effect of nano zinc oxide was the best when the silane coupling agent addition was 6%. The reflection and insulation performance of the coatings were the best when the additions of modified nano zinc oxide, hollow glass microspheres, and sepiolite nanofibers were 3%, 4%, and 4%, respectively. Compared with the control coating materials, the thermal insulation effect was improved obviously, which was evaluated by the -13.5 degrees C increase of maximum temperature difference between the upper and the lower surfaces. PMID:24734652

Wang, Fei; Liang, Jinsheng; Tang, Qingguo; Chen, Gong; Chen, Yalei

2014-05-01

384

The Submillimeter-Wave Astronomy Satellite: On-Orbit Thermal Performance and Design Retrospective  

NASA Technical Reports Server (NTRS)

A large telescope aperture, stringent thermal stability and temperature range requirements, and a passively-cooled 150 K module presented major challenges in thermal design and hardware fabrication of this Small Explorer satellite. This paper reviews briefly the thermal design of the SWAS science instrument, and examines the first three months of on-orbit thermal history. Measured temperatures for both the science payload and the spacecraft module and solar arrays are compared with those predicted by the correlated analytical model. Similarities and differences are interpreted in terms of the major uncertainties remaining after thermal-balance testing, especially those of MLI performance and telescope aperture properties. Review of the thermal model adequacy and thermal design verification are included to suggest improvements in the thermal design process for future missions.

Boyd, David A.; Ousley, Wes; Fantano, Louis; Powers, Edward I. (Technical Monitor)

1999-01-01

385

Weathering of Roofing Materials-An Overview  

SciTech Connect

An overview of several aspects of the weathering of roofing materials is presented. Degradation of materials initiated by ultraviolet radiation is discussed for plastics used in roofing, as well as wood and asphalt. Elevated temperatures accelerate many deleterious chemical reactions and hasten diffusion of material components. Effects of moisture include decay of wood, acceleration of corrosion of metals, staining of clay, and freeze-thaw damage. Soiling of roofing materials causes objectionable stains and reduces the solar reflectance of reflective materials. (Soiling of non-reflective materials can also increase solar reflectance.) Soiling can be attributed to biological growth (e.g., cyanobacteria, fungi, algae), deposits of organic and mineral particles, and to the accumulation of flyash, hydrocarbons and soot from combustion.

Berdahl, Paul; Akbari, Hashem; Levinson, Ronnen; Miller, William A.

2006-03-30

386

40 CFR Appendix A to Subpart M of... - Interpretive Rule Governing Roof Removal Operations  

Code of Federal Regulations, 2011 CFR

...floor covering mastic, and asphalt roofing products containing...roof coatings and mastics; and asphalt-containing...flashings. ACM roofing products...the removal of roofing systems (i.e...coatings, flashings, mastic, shingles, and...

2011-07-01

387

The technical viability of alternative blowing agents in polyisocyanurate roof insulation: A cooperative industry/government project  

SciTech Connect

This report is a summary of the cooperative industry/government program to establish the viability of alternative blowing agents to chlorofluorocarbons (CFCs). The project was initiated in 1989 following two workshops that focused on needed research on thermal insulation blown with substitutes for CFC-11 and CFC-12. The project is directed by a steering committee of representatives of the sponsors and of Oak Ridge National Laboratory (ORNL). The purpose of the project is to determine if the performance of polyisocyanurate (PIR) roof insulation foam boards blown with alternate agents differs from the performance of boards blown with CFC-1. This report describes apparent thermal conductivity (k) results obtained from field and laboratory tests from 1989 to 1992 on a set of experimental PIR laminate boardstock produced to evaluate the viability of alternative hydrochlorofluorocarbons (HCFCs) as blowing agents. All boardstock was manufactured from similar formulations that were not optimized for thermal performance. Commercial broadstock made in the future may differ in performance from this set. The PIR boards were prepared with CFC-11, HCFC-123, HCFC-141b, and 50/50 and 65/35 blends of HCFC-123/HCFC-141b.

Christian, J.E.; Courville, G.E.; Desjarlais, A.O.; Graves, R.S.; Linkous, R.L.; McElroy, D.L.; Weaver, F.J.; Wendt, R.L.; Yarbrough, D.W.

1993-06-01

388

Performance evaluation of a thermal Doppler Michelson interferometer system.  

PubMed

The thermal Doppler Michelson interferometer is the primary element of a proposed limb-viewing satellite instrument called SWIFT (Stratospheric Wind Interferometer for Transport studies). SWIFT is intended to measure stratospheric wind velocities in the altitude range of 15-45 km. SWIFT also uses narrowband tandem etalon filters made of germanium to select a line out of the thermal spectrum. The instrument uses the same technique of phase-stepping interferometry employed by the Wind Imaging Interferometer onboard the Upper Atmosphere Research Satellite. A thermal emission line of ozone near 9 microm is used to detect the Doppler shift due to winds. A test bed was set up for this instrument that included the Michelson interferometer and the etalon filters. For the test bed work, we investigate the behavior of individual components and their combination and report the results. PMID:16318186

Mani, Reza; Dobbie, Steven; Scott, Alan; Shepherd, Gordon; Gault, William; Brown, Stephen

2005-11-20

389

CTS TEP thermal anomalies: Heat pipe system performance  

NASA Technical Reports Server (NTRS)

A part of the investigation is summarized of the thermal anomalies of the transmitter experiment package (TEP) on the Communications Technology Satellite (CTS) which were observed on four occasions in 1977. Specifically, the possible failure modes of the variable conductance heat pipe system (VCHPS) used for principal thermal control of the high-power traveling wave tube in the TEP are considered. Further, the investigation examines how those malfunctions may have given rise to the TEP thermal anomalies. Using CTS flight data information, ground test results, analysis conclusions, and other relevant information, the investigation concentrated on artery depriming as the most likely VCHPS failure mode. Included in the study as possible depriming mechanisms were freezing of the working fluid, Marangoni flow, and gas evolution within the arteries. The report concludes that while depriming of the heat pipe arteries is consistent with the bulk of the observed data, the factors which cause the arteries to deprime have yet to be identified.

Marcus, B. D.

1977-01-01

390

Effects of roof and rainwater characteristics on copper concentrations in roof runoff.  

PubMed

Copper sheeting is a common roofing material used in many parts of the world. However, copper dissolved from roof sheeting represents a source of copper ions to watersheds. Researchers have studied and recently developed a simple and efficient model to predict copper runoff rates. Important input parameters include precipitation amount, rain pH, and roof angle. We hypothesized that the length of a roof also positively correlates with copper concentration (thus, runoff rates) on the basis that runoff concentrations should positively correlate with contact time between acidic rain and the copper sheet. In this study, a novel system was designed to test and model the effects of roof length (length of roof from crown to the drip edge) on runoff copper concentrations relative to rain pH and roof angle. The system consisted of a flat-bottom copper trough mounted on an apparatus that allowed run length and slope to be varied. Water of known chemistry was trickled down the trough at a constant rate and sampled at the bottom. Consistent with other studies, as pH of the synthetic rainwater decreased, runoff copper concentrations increased. At all pH values tested, these results indicated that run length was more important in explaining variability in copper concentrations than was the roof slope. The regression equation with log-transformed data (R(2)?=?0.873) accounted for slightly more variability than the equation with untransformed data (R(2)?=?0.834). In log-transformed data, roof angle was not significant in predicting copper concentrations. PMID:21713491

Bielmyer, Gretchen K; Arnold, W Ray; Tomasso, Joseph R; Isely, Jeff J; Klaine, Stephen J

2012-05-01

391

Thermal performance of windows having high solar transmittance  

SciTech Connect

Antireflected polyester films and low-iron glass sheets have values of solar transmittance that are substantially higher than those of their untreated counterparts. The plastic films utilize coatings to reduce loses due to surface reflectance and the glass is made with low levels of impurities to reduce adsorption within the material itself. The optical and thermal properties of these materials are discussed and the solar and thermal characteristics of windows incorporating high-transmittance glazing layers are derived. Comparisons among these and other types of windows are made on the basis of net energy use for residential buildings in winter.

Rubin, M.; Selkowitz, S.

1981-07-01

392

Alkali metal/halide thermal energy storage systems performance evaluation  

NASA Technical Reports Server (NTRS)

A pseudoheat-pipe heat transfer mechanism has been demonstrated effective in terms of both total heat removal efficiency and rate, on the one hand, and system isothermal characteristics, on the other, for solar thermal energy storage systems of the kind being contemplated for spacecraft. The selection of appropriate salt and alkali metal substances for the system renders it applicable to a wide temperature range. The rapid heat transfer rate obtainable makes possible the placing of the thermal energy storage system around the solar receiver canister, and the immersing of heat transfer fluid tubes in the phase change salt to obtain an isothermal heat source.

Phillips, W. M.; Stearns, J. W.

1986-01-01

393

Performance characterization of fiber Bragg grating thermal response in space vacuum thermal environment  

NASA Astrophysics Data System (ADS)

We investigated the fiber Bragg grating (FBG) thermal response in space vacuum thermal environment. The FBGs were packaged with 6061-T6 aluminum. The liquid nitrogen immersion experiment results show that its wavelength shift standard deviation is 0.76 pm for 217 h. The combination effect of vacuum and cryogenic temperature was studied by thermal cycling process in space environment simulator. The FBG sensors show accuracy better than 2% full scale, and the hysteresis errors are below 1%. It proves that these metal packaged FBG sensors can survive and meet the requirement of space measurement.

Jiang, Junfeng; Song, Luyao; Liu, Tiegen; Zhang, Jingchuan; Liu, Kun; Wang, Shuang; Yin, Jinde; Zhao, Peng; Xie, Jihui; Wu, Fan; Zhang, Xuezhi

2013-12-01

394

The wind resistance of asphalt roofing shingles  

NASA Astrophysics Data System (ADS)

Asphalt shingle roofing is the leading cause of hurricane wind-related insured losses in residential buildings. Damage statistics generated from recent hurricanes indicate shingle roofs sustain damage in wind velocities below design-level with damage frequency increasing with shingle roof age. The objective of this dissertation is the identification of primary mechanisms triggering the failure of shingle roof systems in wind. The research goal is to reduce future shingle roof wind damage and improve our ability to predict asphalt shingle wind resistance. Five studies comprising this dissertation addressed the adhesive consistency and strength of aged asphalt shingles, system-level wind resistance, and the load model underpinning the ASTM D7158 wind test standard. The most significant and unexpected finding was partially unsealed shingles on field, hip, and ridge locations on Florida and Texas homes. Location on the shingle's sealant strip where unsealed and failure mode were consistent at each location. Total quantity of partially unsealed shingles in the field of the roof significantly increased with age, aligning with damage statistics. Full-scale wind tunnel tests demonstrate partially unsealed shingles are more vulnerable than fully sealed due to increased distributed force on sealant strip and concentrated force at the adhered and non-adhered interface. Uplift resistance was measured in artificially and naturally aged shingles. For artificially aged shingles, one of three products evaluated had statistically significant decreases in mean uplift resistance as exposure time increased. However, resistance was above design-level at all exposure test intervals. Naturally aged shingles also had resistance above design-level. Combined results demonstrate that reduced uplift capacity can occur, but high initial bond strength promotes long-term uplift resistance. Wind loads exerted on the shingles sealant strip load path were directly measured on fully sealed and partially unsealed three-tab and laminate shingles. Results indicate that ASTM D7158 and load model is conservative in force prediction for fully sealed shingles. ASTM D7158 is not conservative for partially unsealed shingles. Research concludes that partially unsealed shingles occur naturally and represent a large contributor to wind damage. Retrofit of existing shingle roofs and further work identifying specific cause will provide significant reduction of wind risk in shingle roofing.

Dixon, Craig Robert

395

An empirical analysis of thermal protective performance of fabrics used in protective clothing.  

PubMed

Fabric-based protective clothing is widely used for occupational safety of firefighters/industrial workers. The aim of this paper is to study thermal protective performance provided by fabric systems and to propose an effective model for predicting the thermal protective performance under various thermal exposures. Different fabric systems that are commonly used to manufacture thermal protective clothing were selected. Laboratory simulations of the various thermal exposures were created to evaluate the protective performance of the selected fabric systems in terms of time required to generate second-degree burns. Through the characterization of selected fabric systems in a particular thermal exposure, various factors affecting the performances were statistically analyzed. The key factors for a particular thermal exposure were recognized based on the t-test analysis. Using these key factors, the performance predictive multiple linear regression and artificial neural network (ANN) models were developed and compared. The identified best-fit ANN models provide a basic tool to study thermal protective performance of a fabric. PMID:25135076

Mandal, Sumit; Song, Guowen

2014-10-01

396

The Map to Cost-Effective Summer Roofing.  

ERIC Educational Resources Information Center

Roofing is one of the major expense items in school district maintenance budgets. Outlines steps to take in project planning, developing budget estimates and specifications, and completing a roofing project on time. (MLF)

Waldron, Larry W.

1988-01-01

397

Thermoplastic Single-Ply Roof Relieves Water Damage and Inconvenience.  

ERIC Educational Resources Information Center

Assesses use of thermoplastic single-ply roofs by North Carolina's Mars Hill College to prevent leaks, reduce maintenance costs, and enhance the value of their older historic buildings. Administrators comment on the roof's installation efficiency and cleanliness. (GR)

Williams, Jennifer Lynn

2002-01-01

398

Automatic Roof Plane Detection and Analysis in Airborne Lidar Point Clouds for Solar Potential Assessment  

PubMed Central

A relative height threshold is defined to separate potential roof points from the point cloud, followed by a segmentation of these points into homogeneous areas fulfilling the defined constraints of roof planes. The normal vector of each laser point is an excellent feature to decompose the point cloud into segments describing planar patches. An object-based error assessment is performed to determine the accuracy of the presented classification. It results in 94.4% completeness and 88.4% correctness. Once all roof planes are detected in the 3D point cloud, solar potential analysis is performed for each point. Shadowing effects of nearby objects are taken into account by calculating the horizon of each point within the point cloud. Effects of cloud cover are also considered by using data from a nearby meteorological station. As a result the annual sum of the direct and diffuse radiation for each roof plane is derived. The presented method uses the full 3D information for both feature extraction and solar potential analysis, which offers a number of new applications in fields where natural processes are influenced by the incoming solar radiation (e.g., evapotranspiration, distribution of permafrost). The presented method detected fully automatically a subset of 809 out of 1,071 roof planes where the arithmetic mean of the annual incoming solar radiation is more than 700 kWh/m2. PMID:22346695

Jochem, Andreas; Höfle, Bernhard; Rutzinger, Martin; Pfeifer, Norbert

2009-01-01

399

Automatic roof plane detection and analysis in airborne lidar point clouds for solar potential assessment.  

PubMed

A relative height threshold is defined to separate potential roof points from the point cloud, followed by a segmentation of these points into homogeneous areas fulfilling the defined constraints of roof planes. The normal vector of each laser point is an excellent feature to decompose the point cloud into segments describing planar patches. An object-based error assessment is performed to determine the accuracy of the presented classification. It results in 94.4% completeness and 88.4% correctness. Once all roof planes are detected in the 3D point cloud, solar potential analysis is performed for each point. Shadowing effects of nearby objects are taken into account by calculating the horizon of each point within the point cloud. Effects of cloud cover are also considered by using data from a nearby meteorological station. As a result the annual sum of the direct and diffuse radiation for each roof plane is derived. The presented method uses the full 3D information for both feature extraction and solar potential analysis, which offers a number of new applications in fields where natural processes are influenced by the incoming solar radiation (e.g., evapotranspiration, distribution of permafrost). The presented method detected fully automatically a subset of 809 out of 1,071 roof planes where the arithmetic mean of the annual incoming solar radiation is more than 700 kWh/m(2). PMID:22346695

Jochem, Andreas; Höfle, Bernhard; Rutzinger, Martin; Pfeifer, Norbert

2009-01-01

400

Alkali metal\\/halide thermal energy storage systems performance evaluation  

Microsoft Academic Search

A pseudoheat-pipe heat transfer mechanism has been demonstrated effective in terms of both total heat removal efficiency and rate, on the one hand, and system isothermal characteristics, on the other, for solar thermal energy storage systems of the kind being contemplated for spacecraft. The selection of appropriate salt and alkali metal substances for the system renders it applicable to a

W. M. Phillips; J. W. Stearns

1986-01-01

401

Integrated modeling of nuclear thermal rocket system safety and performance  

Microsoft Academic Search

The Advanced Nuclear Thermal Rocket Engine Simulator (ANTARES) environment, which consistes of an overall architecture employing state-of-the-art computer hardware and an integrated physics simulation nucleus is presented. The ANTARES architecture is described, and its benefits are outlined. In an attempt to demonstrate the fidelity and ability of the physics simulator, a coupled physics methodology for use in simulating design basis

John J. Buksa; William J. Rider; Michael L. Hall

1993-01-01

402

High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems  

SciTech Connect

This document is the sixth volume of the Building America Best Practices Series. It presents information that is useful throughout the United States for enhancing the energy efficiency practices in the specific climate zones that are presented in the first five Best Practices volumes. It provides an introduction to current photovoltaic and solar thermal building practices. Information about window selection and shading is included.

Baechler, M.; Gilbride, T.; Ruiz, K.; Steward, H.; Love, P.

2007-06-01

403

Performance estimation of convective thermal wave adsorption cycles  

Microsoft Academic Search

The convective thermal wave adsorption cycle is described and a thermodynamic model which takes account of the variations in temperature and concentration in the bed is proposed. The results of using the model with a particular carbon adsorbent and ammonia adsorbate are presented for a range of cycle temperatures and system heat transfer effectiveness values.

R. E. Critoph

1996-01-01

404

HelioTrough thermal performance compared to EuroTrough  

Microsoft Academic Search

Parabolic troughs are the most mature technology and have lowest cost compared to other technologies. A comparison between EuroTrough and HelioTrough is carried out in this work. An energy balance model for the trough's absorber tube is used to estimate the optical and thermal losses from the collector. Engineering Equation Solver (EES) was used as a tool to simulate the

A. Bekhit; A. Khalil; S. Kaseb; H. Othman

2012-01-01

405

Analytic model for assessing thermal performance of SCUBA divers  

NASA Technical Reports Server (NTRS)

To assist design of adequate protective clothing, mathematical model of man's thermoregulatory system has been developed so that body thermal responses under immersed conditions can be predicted accurately. Experimental data encompassed wide range of water temperatures, protective clothing, breathing-gas mixtures, and durations of immersion.

Montgomery, L. D.

1975-01-01

406

Evaluation of Physically and Empirically Based Models for the Estimation of Green Roof Evapotranspiration  

NASA Astrophysics Data System (ADS)

Green roofs and other urban green spaces can provide a variety of valuable benefits including reduction of the urban heat island effect, reduction of stormwater runoff, carbon sequestration, oxygen generation, air pollution mitigation etc. As many of these benefits are directly linked to the processes of evaporation and transpiration, accurate and representative estimation of urban evapotranspiration (ET) is a necessary tool for predicting and quantifying such benefits. However, many common ET estimation procedures were developed for agricultural applications, and thus carry inherent assumptions that may only be rarely applicable to urban green spaces. Various researchers have identified the estimation of expected urban ET rates as critical, yet poorly studied components of urban green space performance prediction and cite that further evaluation is needed to reconcile differences in predictions from varying ET modeling approaches. A small scale green roof lysimeter setup situated on the green roof of the Ethical Culture Fieldston School in the Bronx, NY has been the focus of ongoing monitoring initiated in June 2009. The experimental setup includes a 0.6 m by 1.2 m Lysimeter replicating the anatomy of the 500 m2 green roof of the building, with a roof membrane, drainage layer, 10 cm media depth, and planted with a variety of Sedum species. Soil moisture sensors and qualitative runoff measurements are also recorded in the Lysimeter, while a weather station situated on the rooftop records climatologic data. Direct quantification of actual evapotranspiration (AET) from the green roof weighing lysimeter was achieved through a mass balance approaches during periods absent of precipitation and drainage. A comparison of AET to estimates of potential evapotranspiration (PET) calculated from empirically and physically based ET models was performed in order to evaluate the applicability of conventional ET equations for the estimation of ET from green roofs. Results have shown that the empirically based Thornthwaite approach for estimating monthly average PET underestimates compared to AET by 54% over the course of a one year period, and performs similarly on a monthly basis. Estimates of PET from the Northeast Regional Climate Center MORECS model based on a variation of the Penman-Monteith model, overestimates compared to AET by only 2% over a one year period. However, monthly and daily estimates were not accurate, with the model overestimating during warm, summer months by as much as 206% and underestimating during winter months by as much as 58%, which would have significant implications if such estimates were utilized for the evaluation of potential benefits from green roofs. Thus, further evaluation and improvement of these and other methodologies are needed and will be pursued for estimation of ET from green roofs and other urban green spaces including NYC Greenstreets and urban parks.

Digiovanni, K. A.; Montalto, F. A.; Gaffin, S.; Rosenzweig, C.

2010-12-01

407

Attic or Roof? An Evaluation of Two Advanced Weatherization Packages  

SciTech Connect

This project examines implementation of advanced retrofit measures in the context of a large-scale weatherization program and the archetypal Chicago brick bungalow. One strategy applies best practice air sealing methods and a standard insulation method to the attic floor. The other strategy creates an unvented roof assembly using materials and methods typically available to weatherization contractors. Through implementations of the retrofit strategies in a total of eight (8) test homes, the research found that the two different strategies achieve similar reductions in air leakage measurement (55%) and predicted energy performance (18%) relative to the pre-retrofit conditions.

Neuhauser, K.

2012-06-01

408

Design, cost, and performance comparisons of several solar thermal systems for process heat. Volume 3: Receivers  

NASA Astrophysics Data System (ADS)

The receiver subsystem converts reflected solar radiation into thermal power by heating a working fluid. The cost and performance were estimated for the receiver subsystem for parabolic troughs, parabolic dishes, and central receivers over a wide range of temperatures and power levels for thermal power applications. The fundamental design philosophy employed, the constraints identified, the tradeoffs performed and the cost and performance results obtained for each receiver in the study matrix are described.

Woodard, J. B., Jr.

1981-03-01

409

Evaporative Roof Cooling - A Simple Solution to Cut Cooling Costs  

E-print Network

coverage from a 360 degree spray pattern. Careful equipment selection and the expertise of the designer are the fool proof criteria to achieve optimum results. The American Society of Heating 6 Ventilating Engineers (forerunners of ASHRAE) conducted...°F, evaporative roof cooling can actually double or triple the life expectancy of the roof. There are three major factors that destroy a roof. They are: 1. Blisters. Blisters form when the roof temperatures reach 150°F to 160°F. The gravel...

Abernethy, D.

1985-01-01

410

Analysis of Wind Forces on Roof-Top Solar Panel  

NASA Astrophysics Data System (ADS)

Structural loads on solar panels include forces due to high wind, gravity, thermal expansion, and earthquakes. International Building Code (IBC) and the American Society of Civil Engineers are two commonly used approaches in solar industries to address wind loads. Minimum Design Loads for Buildings and Other Structures (ASCE 7-02) can be used to calculate wind uplift loads on roof-mounted solar panels. The present study is primarily focused on 2D and 3D modeling with steady, and turbulent flow over an inclined solar panel on the flat based roof to predict the wind forces for designing wind management system. For the numerical simulation, 3-D incompressible flow with the standard k-? was adopted and commercial CFD software ANSYS FLUENT was used. Results were then validated with wind tunnel experiments with a good agreement. Solar panels with various aspect ratios for various high wind speeds and angle of attacks were modeled and simulated in order to predict the wind loads in various scenarios. The present study concluded to reduce the strong wind uplift by designing a guide plate or a deflector before the panel.

Panta, Yogendra; Kudav, Ganesh

2011-03-01

411

40 CFR 63.1043 - Standards-Separator floating roof.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Standards-Separator floating roof. 63.1043 Section 63.1043... § 63.1043 Standards—Separator floating roof. (a) This section applies...separator or organic-water separator using a floating roof. (b) The separator shall...

2014-07-01

412

AUTOMATED DELINEATION OF ROOF PLANES FROM LIDAR DATA  

Microsoft Academic Search

In this paper, we describe an algorithm for roof line delineation from LIDAR data which aims at achieving models of a high level of detail. Roof planes are initially extracted by segmentation based on the local homogeneity of surface normal vectors of a digital surface model (DSM). A case analysis then reveals which of these roof planes intersect and which

F. Rottensteiner; J. Trinder; S. Clode; K. Kubik

2005-01-01

413

Recovery and reuse of asphalt roofing waste. Final report  

SciTech Connect

Burning of asphalt roofing waste as a fuel and incorporating asphalt roofing waste in bituminous paving were identified as the two outstanding resource recovery concepts out of ten studied. Four additional concepts might be worth considering under different market or technical circumstances. Another four concepts were rated as worth no further consideration at this time. This study of the recovery of the resource represented in asphalt roofing waste has identified the sources and quantities of roofing waste. About six million cubic yards of scrap roofing are generated annually in the United States, about 94% from removal of old roofing at the job site and the remainder from roofing material production at factories. Waste disposal is a growing problem for manufacturers and contractors. Nearly all roofing waste is hauled to landfills at a considerable expense to roofing contractors and manufacturers. Recovery of the roofing waste resource should require only a modest economic incentive. The asphalt contained in roofing waste represents an energy resource of more than 7 x 10/sup 13/ Btu/year. Another 1 x 10/sup 13/ Btu/year may be contained in field-applied asphalt on commercial building roofs. The two concepts recommended by this study appear to offer the broadest applicability, the most favorable economics, and the highest potential for near-term implementation to reuse this resource.

Desai, S.; Graziano, G.; Shepherd, P.

1984-02-02

414

Thermal Performance and Reliability Characterization of Bonded Interface Materials (BIMs): Preprint  

SciTech Connect

Thermal interface materials are an important enabler for low thermal resistance and reliable electronics packaging for a wide array of applications. There is a trend towards bonded interface materials (BIMs) because of their potential for low thermal resistivity (< 1 mm2K/W). However, BIMs induce thermomechanical stresses in the package and can be prone to failures and integrity risks. Deteriorated interfaces can result in high thermal resistance in the package and degradation and/or failure of the electronics. DARPA's Thermal Management Technologies program has addressed this challenge, supporting the development of mechanically-compliant, low resistivity nano-thermal interface (NTI) materials. In this work, we describe the testing procedure and report the results of NREL's thermal performance and reliability characterization of an initial sample of four different NTI-BIMs.

DeVoto, D.; Paret, P.; Mihalic, M.; Narumanchi, S.; Bar-Cohen, A.; Matin, K.

2014-08-01

415

Performance Evaluation and Modeling of Erosion Resistant Turbine Engine Thermal Barrier Coatings  

NASA Technical Reports Server (NTRS)

The erosion resistant turbine thermal barrier coating system is critical to the rotorcraft engine performance and durability. The objective of this work was to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and thermal gradient environments, thus validating a new thermal barrier coating turbine blade technology for future rotorcraft applications. A high velocity burner rig based erosion test approach was established and a new series of rare earth oxide- and TiO2/Ta2O5- alloyed, ZrO2-based low conductivity thermal barrier coatings were designed and processed. The low conductivity thermal barrier coating systems demonstrated significant improvements in the erosion resistance. A comprehensive model based on accumulated strain damage low cycle fatigue is formulated for blade erosion life prediction. The work is currently aiming at the simulated engine erosion testing of advanced thermal barrier coated turbine blades to establish and validate the coating life prediction models.

Miller, Robert A.; Zhu, Dongming; Kuczmarski, Maria

2008-01-01

416

Optical-thermal performance analysis for a fixed mirror-distributed focus solar-thermal-electric power system  

Microsoft Academic Search

This paper is concerned with both optical and thermal analyses for a fixed mirror-distributed focus (FMDF) system. This work has arisen as a part of the Crosbyton Solar Power Project at Texas Tech University. The paper addresses both detailed and approximation modeling of the optical concentration profiles and modeling of receiver performance for a once-through steam boiler receiver for the

L. D. Clements; J. D. Reichert

1979-01-01

417

Solar thermal absorption heat pump breakeven coefficient of performance  

Microsoft Academic Search

This paper compares the performance of direct solar heating with heating obtained with solar energy amplified through an absorption heat pump. It is shown that if the performance of the two systems is to be at least equal under similar operating conditions, the absorption heat pump must have a minimum heating coefficient of performance (COP)H, which is defined as the

M. Balasubramaniam; G. L. Schrenk; A. Lowi; J. C. Denton

1974-01-01

418

A parabolic dish\\/AMTEC solar thermal power system and its performance evaluation  

Microsoft Academic Search

This paper proposes a parabolic dish\\/AMTEC solar thermal power system and evaluates its overall thermal–electric conversion performance. The system is a combined system in which a parabolic dish solar collector is cascaded with an alkali metal thermal to electric converter (AMTEC) through a coupling heat exchanger. A separate type heat-pipe receiver is selected to isothermally transfer the solar energy from

Shuang-Ying Wu; Lan Xiao; Yiding Cao; You-Rong Li

2010-01-01

419

Performance of finned thermal capacitors. Ph.D. Thesis - Texas Univ., Austin  

NASA Technical Reports Server (NTRS)

The performance of typical thermal capacitors, both in earth and orbital environments, was investigated. Techniques which were used to make predictions of thermal behavior in a one-g earth environment are outlined. Orbital performance parameters are qualitatively discussed, and those effects expected to be important under zero-g conditions are outlined. A summary of thermal capacitor applications are documentated, along with significant problem areas and current configurations. An experimental program was conducted to determine typical one-g performance, and the physical significance of these data is discussed in detail. Numerical techniques were employed to allow comparison between analytical and experimental data.

Humphries, W. R.

1974-01-01

420

Integrated modeling of nuclear thermal rocket system safety and performance  

NASA Astrophysics Data System (ADS)

The Advanced Nuclear Thermal Rocket Engine Simulator (ANTARES) environment, which consistes of an overall architecture employing state-of-the-art computer hardware and an integrated physics simulation nucleus is presented. The ANTARES architecture is described, and its benefits are outlined. In an attempt to demonstrate the fidelity and ability of the physics simulator, a coupled physics methodology for use in simulating design basis accidents is presented. A preliminary high-resolution, heat-transfer model for use in ANTARES is also presented.

Buksa, John J.; Rider, William J.; Hall, Michael L.

1993-01-01

421

High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems  

NSDL National Science Digital Library

The Advanced Technology Environmental and Energy Center (ATEEC) provides this document, which was created by the U.S. Department of Energy, on solar thermal and photovoltaic systems. In addition to providing a general overview of these energy technologies, the document also includes a number of useful case studies highlighting construction projects which use energy efficient methods and equipment. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

422

Integrated modeling of nuclear thermal rocket system safety and performance  

SciTech Connect

The Advanced Nuclear Thermal Rocket Engine Simulator (ANTARES) environment, which consistes of an overall architecture employing state-of-the-art computer hardware and an integrated physics simulation nucleus is presented. The ANTARES architecture is described, and its benefits are outlined. In an attempt to demonstrate the fidelity and ability of the physics simulator, a coupled physics methodology for use in simulating design basis accidents is presented. A preliminary high-resolution, heat-transfer model for use in ANTARES is also presented.

Buksa, J.J.; Rider, W.J.; Hall, M.L. (Los Alamos National Laboratory, Reactor Design and Analysis Group, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States))

1993-01-20

423

Ballistic Performance of Porous-Ceramic, Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

Porous-ceramic, thermal protection systems are used heavily in current reentry vehicles like the Orbiter, and they are currently being proposed for the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on 8 lb/cu ft alumina-fiber-enhanced-thermal-barrier (AETB8) tiles coated with a toughened-unipiece-fibrous-insulation/ reaction-cured-glass layer (TUFI/RCG). A semi-empirical, first principals impact model that describes projectile dispersion is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials. Model extensions to look at the implications of greater than 10 GPa equation of state is also discussed. Predicted penetration probabilities for a vehicle visiting the International Space Station is 60% lower for orbital debris and 95% lower for meteoroids with this model compared to an energy scaled approach.

Miller, J. E.; Bohl, W. E.; Christiansen, Eric C.; Davis, B. A.; Foreman, C. D.

2011-01-01

424

Flightweight radiantly and actively cooled panel: Thermal and structural performance  

NASA Technical Reports Server (NTRS)

A 2- by 4-ft flightweight panel was subjected to thermal/structural tests representative of design flight conditions for a Mach 6.7 transport and to off-design conditions simulating flight maneuvers and cooling system failures. The panel utilized Rene 41 heat shields backed by a thin layer of insulation to radiate away most of the 12 Btu/ft2-sec incident heating. A solution of ethylene glycol in water circulating through tubes in an aluminum-honeycomb-sandwich panel absorbed the remainder of the incident heating (0.8 Btu/sq ft-sec). The panel successfully withstood (1) 46.7 hr of radiant heating which included 53 thermal cycles and 5000 cycles of uniaxial inplane loading of + or - 1200 lfb/in; (2) simulated 2g-maneuver heating conditions and simulated cooling system failures without excessive temperatures on the structural panel; and (3) the extensive thermal/structural tests and the aerothermal tests reported in NASA TP-1595 without significant damage to the structural panel, coolant leaks, or hot-gas ingress to the structural panel.

Shore, C. P.; Nowak, R. J.; Kelly, H. N.

1982-01-01

425

COOL ROOF COATINGS INCORPORATING GLASS HOLLOW MICROSPHERES  

EPA Science Inventory

Solar Gain is in part responsible for up to 56% of energy consumed by cooling systems in residential buildings. By reflecting and scattering radiant energy from the sun, the surface temperature of exterior walls and roofs can be greatly reduced. Previous studies have indicated...

426

SOLAR ROOF POWERS THE NJIT CAMPUS CENTER  

E-print Network

absorb whatever light is left in the night sky. It's fascinating. In an age when natural resources the university nearly $30,000 a year in electric bills. NJIT received a $216,000 rebate from the New Jersey Board on the roof of the new Campus Center. Baptiste, who graduated from NJIT in 1991 with a degree in electrical

Bieber, Michael

427

Roof Shield for Advance and Retreat Mining  

NASA Technical Reports Server (NTRS)

Shield sections change their configuration to suit mining mode. Articulation cylinders raise rear shield to advance position, and locking cylinders hold it there. To change to retreat position articulation cylinders lower shield. Locking pins at edge of outermost shield plate latch shield to chock base. Shield accommodates roof heights ranging from 36 to 60 inches (0.9 to 1.52 meters).

Lewis, E. V.

1985-01-01

428

Heat Shielding Characteristics and Thermostructural Performance of a Superalloy Honeycomb Sandwich Thermal Protection System (TPS)  

NASA Technical Reports Server (NTRS)

Heat-transfer, thermal bending, and mechanical buckling analyses have been performed on a superalloy "honeycomb" thermal protection system (TPS) for future hypersonic flight vehicles. The studies focus on the effect of honeycomb cell geometry on the TPS heat-shielding performance, honeycomb cell wall buckling characteristics, and the effect of boundary conditions on the TPS thermal bending behavior. The results of the study show that the heat-shielding performance of a TPS panel is very sensitive to change in honeycomb core depth, but insensitive to change in honeycomb cell cross-sectional shape. The thermal deformations and thermal stresses in the TPS panel are found to be very sensitive to the edge support conditions. Slight corrugation of the honeycomb cell walls can greatly increase their buckling strength.

Ko, William L.

2004-01-01

429

Recovery and reuse of asphalt roofing waste burning of asphalt roofing waste  

SciTech Connect

The research described in this report was designed to determine the general feasibility and specific requirements for burning asphalt roofing waste and recovering the energy resource as steam. The study combined technical market research with test burning in a three-task program to identify how to use burning as a means for reocvering the 7 x 10/sup 13/ Btu in roofing waste landfilled annually.

Zolnick, E.L.; Markus, A.R.; Seigfried, J.N.; Powers, T.J.; Shepherd, P.B.; Graziano, G.J.; Battles, R.L.

1986-09-15

430

Performance evaluation of photovoltaic thermal solar air collector for composite climate of India  

Microsoft Academic Search

The objective of present study is to evaluate the performance of the photovoltaic (PV) module integrated with air duct for composite climate of India. In this case, thermal energy is produced along with electrical energy generated by a PV module with higher efficiency. An analytical expression for an overall efficiency (electrical and thermal) has been derived by using energy balance

Arvind Tiwari; M. S. Sodha; Avinash Chandra; J. C. Joshi

2006-01-01

431

A mathematical model of thermal performance of a solar air heater with slats  

Microsoft Academic Search

A mathematical model for computing the thermal performance of a single pass flat-plate solar air collector is presented. Air channels were formed by providing metal slats running along the circulated air passage linking the absorber plate by the bottom one in an endeavor to enhance the thermal efficiency of the solar air collector. A mathematical model, therefore, is developed by

H. D. Ammari

2003-01-01

432

Exergetic performance assessment of a solar photovoltaic thermal (PV\\/T) air collector  

Microsoft Academic Search

In this paper, an attempt is made to evaluate the exergetic performance of a solar photovoltaic thermal (PV\\/T) air collector. A detailed energy and exergy analysis is carried out to calculate the thermal and electrical parameters, exergy components and exergy efficiency of a typical PV\\/T air collector. Some corrections are done on related heat loss coefficients. An improved electrical model

F. Sarhaddi; S. Farahat; H. Ajam; A. Behzadmehr

2010-01-01

433

Comparative study of the performances of four photovoltaic\\/thermal solar air collectors  

Microsoft Academic Search

An extensive investigation of the thermal, electrical, hydraulic and overall performances of flat plate photovoltaic\\/thermal (PV\\/T) air collectors has been made. Four popular designs are considered with the air flowing either over the absorber (Model I) or under it (Model II) and on both sides of the absorber in a single pass (Model III) or in a double pass fashion

Adel A. Hegazy

2000-01-01

434

Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models  

E-print Network

1 Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models distilled from measure data, rather than models derived from transformer heat for measuring the acceptability of transformer thermal models. For a model to be acceptable, it must have

435

Thermal performance and biological evaluation of solar water disinfection systems using parabolic trough collectors  

Microsoft Academic Search

Thermal and optical performance of solar water disinfecting systems using parabolic trough collector, PTC, have been investigated experimentally and numerically. Four PTCs systems were designed, manufactured and field tested under the same weather conditions of Cairo 30°N. The four systems were installed to be compared thermally and biologically. Each system consists of a 2-m PTC and line-focus pipe to carry

A. M. Abdel Dayem; H. H. El-Ghetany; G. E. El-Taweel; M. M. Kamel

2011-01-01

436

THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER  

E-print Network

THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER Dennis L. Youchison-channel, helium-cooled heat exchanger made almost entirely of tungsten was designed and fabricated by Thermacore exchanger, while a second monitored flow in only one of the channels. The thermal response of the tungsten

California at Los Angeles, University of

437

Analytical predictions of liquid and air photovoltaic\\/thermal, flat-plate collector performance  

Microsoft Academic Search

Two separate one-dimensional analyses have been developed for the prediction of the thermal and electrical performance of both liquid and air flat-plate, photovoltaic\\/thermal (PV\\/T) collectors. The results of the analyses are compared with test measurements, and therefrom design recommendations are made to maximize the total energy extracted from the collectors. 16 refs.

P. Raghuraman

1981-01-01

438

Thermal performance study and evaluation of comfort temperatures in vernacular buildings of North-East India  

Microsoft Academic Search

Solar passive techniques are being used in vernacular buildings throughout the world. Researchers have done extensive study on thermal performance of vernacular buildings in the different parts of the world. Vernacular architecture of North-Eastern India represents the principle of climate-responsive architecture, which still lacks experimental validation and quantitative analysis. Thermal comfort not only makes the occupants comfortable but also governs

Manoj Kumar Singh; Sadhan Mahapatra; S. K. Atreya

2010-01-01

439

Effects of different multiple PCMs on the performance of a latent thermal energy storage system  

Microsoft Academic Search

The present study presents a theoretical model for the performance of a shell and tube latent thermal energy storage (LTES) unit using multiple phase change materials (PCMs). The model is based on the enthalpy method. Numerical simulations are carried out to investigate the effects of different multiple PCMs on the melted fraction, stored thermal energy and fluid outlet temperature of

Ming Fang; Guangming Chen

2007-01-01

440

Development of non-destructive inspection method for the performance of thermal barrier coating.  

PubMed

This paper shows that our proprietary non-destructive inspection method can be used to effectively measure the thermal barrier performance of the thermal barrier coating used to coat gas turbine hot parts by the results of numerical analysis and laboratory experiments. PMID:11460665

Morinaga, M; Takahashi, T

2001-05-01