Sample records for roof thermal performance

  1. Thermal Performance of Vegetative Roofing Systems

    SciTech Connect

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

    2010-01-01

    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.

  2. Effect of Surface Mass on Roof Thermal Performance

    E-print Network

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

    1988-01-01

    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...

  3. Comparative Summer Attic Thermal Performance of Six Roof Constructions

    Microsoft Academic Search

    D. S. Parker; J. R. Sherwin

    2002-01-01

    Florida Solar Energy Center (FSEC) has measured summer attic thermal performance of six roofs at a heavily instrumented test site, the Flexible Roof Facility (FRF). The FRF is a 1,152 square foot (107 m2) building with six roof adjacent test cells which are heavily insulated from each other. Some 233 channels of data were obtained; this includes twenty temperature measurements

  4. Thermal Performance of Vegetative Roofing Systems

    Microsoft Academic Search

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

    2010-01-01

    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

  5. Thermal Performance of Vegetative Roofing Systems Andre O. Desjarlais, Abdi Zaltash, and Jerald A. Atchley

    E-print Network

    Oak Ridge National Laboratory

    cooling loads) compared to the white control system due to the thermal mass, extra insulation, and evapoThermal Performance of Vegetative Roofing Systems Andre O. Desjarlais, Abdi Zaltash, and Jerald A, and beautification of the surroundings by incorporating green space. The vegetative roof research project at Oak

  6. Thermal testing of roof systems

    Microsoft Academic Search

    D. C. Larson; R. D. Corneliussen

    1981-01-01

    A comprehensive program to investigate the thermal performance of insulated flat roofs has been developed at Drexel University in Philadelphia. A number of 1.22-m (4-ft)-square roof systems have been sealed into expanded polystyrene (EPS) modules and placed in a horizontal array on the roof of a Drexel building. The roof specimens are exposed to the outdoor urban environment and at

  7. Thermal testing of roof systems

    Microsoft Academic Search

    D. C. Larson; R. D. Corneliussen

    1983-01-01

    A comprehensive program to investigate the thermal performance of insulated flat roofs has been developed at Drexel University in Philadelphia. A number of 1.22-m (4-ft)-square roof systems have been sealed into expanded polystyrene (EPS) modules and placed in a horizontal array on the roof of a Drexel building. The roof specimens are exposed to the outdoor urban environment and at

  8. In situ thermal performance of APP modified bitumen roof membranes coated with reflective coatings

    SciTech Connect

    Carlson, J.D.; Smith, T.L. (National Roofing Contractors Association, Rosemont, IL (United States)); Christian, J.E. (Oak Ridge National Lab., TN (United States))

    1992-01-01

    A multi-faceted field research program regarding seven atactic polypropylene (APP) modified bitumen membrane roof systems and four reflective coatings began in 1991. This long-term project is evaluating the performance of various APP modified bitumen membranes (both coated and uncoated), the comparative performance of coating application soon after membrane installation versus preweathering, coating performance, and aspects of recoating. This paper is a progress report on the in situ thermal performance of the various types of coatings compared to the thermal performance of the exposed membrane. The thermal performance of an adjacent ballasted ethylene propylene diene terpolymer (EPDM) roofing system is also described.

  9. In situ thermal performance of APP modified bitumen roof membranes coated with reflective coatings

    SciTech Connect

    Carlson, J.D.; Smith, T.L. [National Roofing Contractors Association, Rosemont, IL (United States); Christian, J.E. [Oak Ridge National Lab., TN (United States)

    1992-10-01

    A multi-faceted field research program regarding seven atactic polypropylene (APP) modified bitumen membrane roof systems and four reflective coatings began in 1991. This long-term project is evaluating the performance of various APP modified bitumen membranes (both coated and uncoated), the comparative performance of coating application soon after membrane installation versus preweathering, coating performance, and aspects of recoating. This paper is a progress report on the in situ thermal performance of the various types of coatings compared to the thermal performance of the exposed membrane. The thermal performance of an adjacent ballasted ethylene propylene diene terpolymer (EPDM) roofing system is also described.

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

    NASA Astrophysics Data System (ADS)

    Mukherjee, Sananda

    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.

  11. Energy performance of fabric roofs

    SciTech Connect

    Beitin, K.I.

    1982-06-01

    The energy efficiency of fabric roofs is dependent on the thermal and optical characteristics of the fabric envelope. Vinyl coated polyester is used in temporary inflated ''bubbles''. Teflon coated fiberglass has been used in permanent structures such as the Pontiac Silverdome. Daylighting through the fabric is ample, but heat loss can be high in cold climates. The roof performs better in warm than in cold climates. The energy performance of the roof then depends on balancing gains from daylighting against heat loss. New fabrics utilizing daylighting with higher insulation values are being developed. Pneumatically operated fabric lenses for the new Denver Federal Office Building open and close to control heat loss, for example.

  12. FULL YEAR PERFORMANCE SIMULATION OF A DIRECT-COOLED THERMAL STORAGE ROOF (DCTSR) IN THE MIDWEST

    Microsoft Academic Search

    Richard C. Bourne; Bing Chen

    1990-01-01

    Previous papers by the authors describe the direct-cooled thermal storage roof (DCTSR) concept and prior small-scale developmental and monitoring work. DCTSR water containment is provided by a single-ply roof membrane in thermal contact with occupied space below. Hard-topped rigid insulation panels float on the 311 to 411 water storage layer. During summer nights, storage water is distributed above the insulation

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

    E-print Network

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

    2010-01-01

    is considered the major part of the building envelop which exposed to high thermal load due to the high solar intensity and high outdoor air temperature through summer season which reach to 6 months. In Egypt the thermal effect of roof is increased as one go...

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

    E-print Network

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

    2010-01-01

    is considered the major part of the building envelop which exposed to high thermal load due to the high solar intensity and high outdoor air temperature through summer season which reach to 6 months. In Egypt the thermal effect of roof is increased as one go...

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

    E-print Network

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

    2004-01-01

    of five roofing systems against a control roof using dark shingles. The intent of the testing is to evaluate how roofing systems impact residential cooling energy use. Recent testing emphasizes evaluation of how increasingly popular metal roofing systems...

  16. 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

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

    2008-01-01

    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

  17. Analysis of the green roof thermal properties and investigation of its energy performance

    Microsoft Academic Search

    A. Niachou; K Papakonstantinou; M Santamouris; A Tsangrassoulis; G Mihalakakou

    2001-01-01

    The advantages of the planned roofs are undoubtedly numerous from both the ecological and the social point of view. They act positively upon the climate of the city and its region, as well as upon the interior climate of the buildings beneath them. They give protection from the solar radiation, which is the main factor in passive cooling. By reducing

  18. Roof system effects on in-situ thermal performance of HCFC polyisocyanurate insulation. [Hydrochlorofluorocarbon (HCFC)

    Microsoft Academic Search

    J. E. Christian; A. O. Desjarlais; G. Courville; R. Graves

    1992-01-01

    Industry-produced, permeably-faced, experimental polyisocyanurate (PIR) laminated boardstock foamed with several different hydrochlorofluorcarbons (HCFCS) is undergoing in-situ testing at the Building Envelopes Research User Center at Oak Ridge National Laboratory (ORNL). The overall objective of this research is to determine the long term thermal performance differences between PIR foamed with CFC-11 and PIR foamed with HCFC-123, HCFC-14lb and blends of HCFCs.

  19. Roof system effects on in-situ thermal performance of HCFC polyisocyanurate insulation

    Microsoft Academic Search

    J. E. Christian; A. O. Desjarlais; G. Courville; R. Graves

    1992-01-01

    Industry-produced, permeably-faced, experimental polyisocyanurate (PIR) laminated boardstock foamed with several different hydrochlorofluorcarbons (HCFCS) is undergoing in-situ testing at the Building Envelopes Research User Center at Oak Ridge National Laboratory (ORNL). The overall objective of this research is to determine the long term thermal performance differences between PIR foamed with CFC-11 and PIR foamed with HCFC-123, HCFC-14lb and blends of HCFCs.

  20. The contribution of a planted roof to the thermal protection of buildings in Greece

    Microsoft Academic Search

    Ekaterini Eumorfopoulou; Dimitris Aravantinos

    1998-01-01

    Planted roofs contribute positively to the improvement of the thermal performance of a building. They block solar radiation, and reduce daily temperature variations and thermal ranges between winter and summer. In this paper, a calculation has been done, using a stationary method, in order to determine the thermal behaviour of the planted roof and the way it influences the thermal

  1. Energy Performance Aspects of a Florida Green Roof 

    E-print Network

    Sonne, J.

    2006-01-01

    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... and roof heat flux, and simulations indicate cooling load reductions of up to 25%. This monitored study evaluates summer and winter energy performance aspects of a green roof on a central Florida university building addition that was completed in 2005...

  2. Thermal patterns in the snow: Structure of a roof

    NASA Astrophysics Data System (ADS)

    Bartlett, Albert A.

    1999-02-01

    A dramatic thermal pattern on the south-facing roof of our university's Fine Arts building is shown in analyzed. From the patterns in the snow on the roof, it is possible to draw a number of tentative conclusions about the makeup and structure of the roof.

  3. Roof Integrated Solar Absorbers: The Measured Performance of ''Invisible'' Solar Collectors: Preprint

    Microsoft Academic Search

    C. J. Colon; T. Merrigan

    2001-01-01

    The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory, has investigated the thermal performance of solar absorbers that are an integral, yet indistinguishable, part of a building's roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC's Flexible Roof Facility in Cocoa, Florida, in September 1998. This ''proof-of-concept'' system uses the asphalt

  4. Energy Performance Aspects of a Florida Green Roof Part 2 

    E-print Network

    Sonne, J.; Parker, D.

    2008-01-01

    Green roof installation in the United States is growing at a significant rate. There are a number of reasons for this growth including rainwater runoff reduction and aesthetic benefits. Energy performance evaluations of green roofs, the subject...

  5. Wind performance evaluation of fully bonded roofing assemblies

    Microsoft Academic Search

    A. Baskaran; S. Molleti; M. Sexton

    2008-01-01

    Wind performance investigation is critical in the design of durable roofing assemblies. In North America, mainly two types of low slope roofs, conventional and inverted, are in practice depending on the placement of the membrane in the system. The present study focuses on the wind uplift performance of fully bonded single ply roofing assembly. Past studies focused on the wind

  6. Roof Integrated Solar Absorbers: The Measured Performance of ''Invisible'' Solar Collectors: Preprint

    SciTech Connect

    Colon, C. J. (Florida Solar Energy Center); Merrigan, T. (National Renewable Energy Laboratory)

    2001-10-19

    The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory, has investigated the thermal performance of solar absorbers that are an integral, yet indistinguishable, part of a building's roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC's Flexible Roof Facility in Cocoa, Florida, in September 1998. This ''proof-of-concept'' system uses the asphalt shingle roof surface and the plywood decking under the shingles as an unglazed solar absorber. Data was gathered for a one-year period on the system performance. In Phase 2, two more RISA prototypes were constructed and submitted for testing. The first used the asphalt shingles on the roof surface with the tubing mounted on the underside of the plywood decking. The second prototype used metal roofing panels over a plywood substrate and placed the polymer tubing between the plywood decking and the metal roofing. This paper takes a first look at the thermal performance results for the ''invisible'' solar absorbers that use the actual roof surface of a building for solar heat collection.

  7. Roof heat loss detection using airborne thermal infrared imagery

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  8. Thermal resistance of prototypical cellular plastic roof insulations

    Microsoft Academic Search

    D. L. McElroy; R. S. Graves; F. J. Weaver

    1991-01-01

    A cooperative industry\\/government project was initiated in 1989 to evaluate the viability of alternative hydrochlorofluorocarbons (HCFCs) as blowing agents in polyisocyanurate (PIR) boardstock for roofing applications. Five sets of PIR boardstock were produced to industry specifications for current roof insulation technology. The boardstock allowed the performance of four alternative blowing agents (HCFC-123, HCFC-14lb, and two blends of HCFC-123 and HCFC-14lb)

  9. Performance of dryland and wetland plant species on extensive green roofs

    PubMed Central

    MacIvor, J. Scott; Ranalli, Melissa A.; Lundholm, Jeremy T.

    2011-01-01

    Background and Aims Green roofs are constructed ecosystems where plants perform valuable services, ameliorating the urban environment through roof temperature reductions and stormwater interception. Plant species differ in functional characteristics that alter ecosystem properties. Plant performance research on extensive green roofs has so far indicated that species adapted to dry conditions perform optimally. However, in moist, humid climates, species typical of wetter soils might have advantages over dryland species. In this study, survival, growth and the performance of thermal and stormwater capture functions of three pairs of dryland and wetland plant species were quantified using an extensive modular green roof system. Methods Seedlings of all six species were germinated in a greenhouse and planted into green roof modules with 6 cm of growing medium. There were 34 treatments consisting of each species in monoculture and all combinations of wet- and dryland species in a randomized block design. Performance measures were survival, vegetation cover and roof surface temperature recorded for each module over two growing seasons, water loss (an estimate of evapotranspiration) in 2007, and albedo and water capture in 2008. Key Results Over two seasons, dryland plants performed better than wetland plants, and increasing the number of dryland species in mixtures tended to improve functioning, although there was no clear effect of species or habitat group diversity. All species had survival rates >75 % after the first winter; however, dryland species had much greater cover, an important indicator of green roof performance. Sibbaldiopsis tridentata was the top performing species in monoculture, and was included in the best treatments. Conclusions Although dryland species outperformed wetland species, planting extensive green roofs with both groups decreased performance only slightly, while increasing diversity and possibly habitat value. This study provides further evidence that plant composition and diversity can influence green roof functions. PMID:21292676

  10. Performance evaluation of the BSRC multi-purpose bio-climatic roof

    Microsoft Academic Search

    J. Waewsak; J. Hirunlabh; J. Khedari; U. C. Shin

    2003-01-01

    This paper reports on experimental investigation of the performance of a new multi-purpose bio-climatic roof (BCR) developed by our teamwork (The Building Scientific Research Center, BSRC). The innovative functions of this BSRC-BCR are to decrease daily heat gain through the roof fabrics, to induce significant air ventilation rate, which improves the thermal comfort of residents, to ensure appropriate daylighting without

  11. Hygrothermal Performance of West Coast Wood Deck Roofing System

    SciTech Connect

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

    2014-02-01

    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.

  12. System for monitoring of green roof performance: use of weighing roof segment and non-invasive visualization

    NASA Astrophysics Data System (ADS)

    Jelinkova, Vladmira; Dohnal, Michal; Picek, Tomas; Sacha, Jan

    2015-04-01

    Understanding the performance of technogenic substrates for green roofs is a significant task in the framework of sustainable urban planning and water/energy management. The potential retention and detention of the anthropogenic, light weight soil systems and their temporal soil structure changes are of major importance. A green roof test segment was built to investigate the benefits of such anthropogenic systems. Adaptable low-cost system allows long-term monitoring of preferred characteristics. Temperature and water balance measurements complemented with meteorological observations and knowledge of physical properties of the substrates provide basis for detailed analysis of thermal and hydrological regime in green roof systems. The first results confirmed the benefits of green roof systems. The reduction of temperature fluctuations as well as rainfall runoff was significant. Depending on numerous factors such substrate material or vegetation cover the test green roof suppressed the roof temperature amplitude for the period analyzed. The ability to completely prevent (light rainfall events) or reduce and delay (medium and heavy rainfall events) the peak runoff was also analyzed. Special attention is being paid to the assessment of soil structural properties related to possible aggregation/disaggregation, root growth, weather conditions and associated structural changes using non-invasive imaging method. X-ray computed microtomography of undisturbed soil samples (taken from experimental segments) is used for description of pore space geometry, evaluation of surface to volume ratio, additionally for description of cracks and macropores as a product of soil flora and fauna activity. The information from computed tomography imaging will be used for numerical modeling of water flow in variable saturated porous media. The research was realized as a part of the University Centre for Energy Efficient Buildings supported by the EU and with financial support from the Czech Science Foundation under project number 14-10455P.

  13. Green roof hydrologic performance and modeling: a review.

    PubMed

    Li, Yanling; Babcock, Roger W

    2014-01-01

    Green roofs reduce runoff from impervious surfaces in urban development. This paper reviews the technical literature on green roof hydrology. Laboratory experiments and field measurements have shown that green roofs can reduce stormwater runoff volume by 30 to 86%, reduce peak flow rate by 22 to 93% and delay the peak flow by 0 to 30 min and thereby decrease pollution, flooding and erosion during precipitation events. However, the effectiveness can vary substantially due to design characteristics making performance predictions difficult. Evaluation of the most recently published study findings indicates that the major factors affecting green roof hydrology are precipitation volume, precipitation dynamics, antecedent conditions, growth medium, plant species, and roof slope. This paper also evaluates the computer models commonly used to simulate hydrologic processes for green roofs, including stormwater management model, soil water atmosphere and plant, SWMS-2D, HYDRUS, and other models that are shown to be effective for predicting precipitation response and economic benefits. The review findings indicate that green roofs are effective for reduction of runoff volume and peak flow, and delay of peak flow, however, no tool or model is available to predict expected performance for any given anticipated system based on design parameters that directly affect green roof hydrology. PMID:24569270

  14. Experimental investigation and numerical simulation analysis on the thermal performance of a building roof incorporating phase change material (PCM) for thermal management

    Microsoft Academic Search

    A. Pasupathy; L. Athanasius; R. Velraj; R. V. Seeniraj

    2008-01-01

    Thermal storage plays a major role in a wide variety of industrial, commercial and residential application when there is a mismatch between the supply and demand of energy. Latent heat storage in a phase change material (PCM) is very attractive, because of its high-energy storage density and its isothermal behavior during the phase change process. Several promising developments are taking

  15. Hamerschlag Hall Green Roof Storm Water Retention and Runoff Reduction Performance Lucheng Chen

    E-print Network

    Andrews, Peter B.

    Hamerschlag Hall Green Roof Storm Water Retention and Runoff Reduction Performance ......................................................................................................................... 2 2. Hamerschlag Hall Green Roof ............................................................................................................................ 6 3.2. Ultrasonic Sensors

  16. THE IMPACT OF ABOVE-SHEATHING VENTILATION ON THE THERMAL AND MOISTURE PERFORMANCE OF STEEP-SLOPE RESIDENTIAL ROOFS AND ATTICS

    Microsoft Academic Search

    Joe Wilson; Achilles Karagiozis

    Field studies were conducted on several attic assemblies having stone-coated metal shake roofs 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 with the heat flow penetrating the attic floor of a roof with

  17. ManualforEvaluatingtheThermalPerformanceofthe HamerschlagHallGreenRoof

    E-print Network

    Andrews, Peter B.

    combined sewer overflows. Reduced "urban heat island" effect ­ A green roof reduces the level of absorbed heat in dense concrete areas. Extended life of the roof ­ Protects the roof from weather, reducing maintenance costs. Reduced heating and cooling costs ­ Provides extra roof insulation. And reduction

  18. Modelling of green roof hydrological performance for urban drainage applications

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  19. Energy Performance Aspects of a Florida Green Roof Part 2

    E-print Network

    Sonne, J.; Parker, D.

    variety of primarily native Florida vegetation up to approximately 2 feet in height to create an extensive green roof. Analysis of 2005 summer data from the first year the green roof was installed indicates significantly lower peak roof surface...

  20. The design, effectiveness and construction of passive-thermal-control roofing shingles

    NASA Astrophysics Data System (ADS)

    Wolf, L., Jr.

    1982-09-01

    The concept of a passive thermal control roofing shingle, which is a shingle that reflects the summer sun and absorbs the winter sun, is discussed. It is indicated that it is possible to design shingles for particular latitudes and styles of roof which absorb nearly all of the winter solar energy and reflect nearly all of the summer solar energy. Calculations of the energy savings and cost effectiveness of the passive thermal control roofing shingle indicate that it is most cost effective on all south facing pitched roofs regardless of heating fuel type, and on flat or east or west facing roofs that are heated with costly fuels such as electricity or heating oil. The shingle is most effective on poorly insulated structures. The feasibility of using the passive thermal control roofing shingle in conjunction with a heat pump to pump heat absorbed by the shingle into a well insulated structure is demonstrated. Construction of a variety of models of the passive thermal control roofing shingle illustrate numerous alternate methods of manufacture. A profile extruded, plastic, glazed shingle appears to be the most promising approach. Use of a glazed shingle can increase the effectiveness of the passive thermal control roofing shingle by reducing convective heat losses.

  1. The design, effectiveness and construction of passive-thermal-control roofing shingles

    Microsoft Academic Search

    L. Wolf Jr.

    1982-01-01

    The concept of a passive thermal control roofing shingle, which is a shingle that reflects the summer sun and absorbs the winter sun, is discussed. It is indicated that it is possible to design shingles for particular latitudes and styles of roof which absorb nearly all of the winter solar energy and reflect nearly all of the summer solar energy.

  2. A modelling study of long term green roof retention performance.

    PubMed

    Stovin, Virginia; Poë, Simon; Berretta, Christian

    2013-12-15

    This paper outlines the development of a conceptual hydrological flux model for the long term continuous simulation of runoff and drought risk for green roof systems. A green roof's retention capacity depends upon its physical configuration, but it is also strongly influenced by local climatic controls, including the rainfall characteristics and the restoration of retention capacity associated with evapotranspiration during dry weather periods. The model includes a function that links evapotranspiration rates to substrate moisture content, and is validated against observed runoff data. The model's application to typical extensive green roof configurations is demonstrated with reference to four UK locations characterised by contrasting climatic regimes, using 30-year rainfall time-series inputs at hourly simulation time steps. It is shown that retention performance is dependent upon local climatic conditions. Volumetric retention ranges from 0.19 (cool, wet climate) to 0.59 (warm, dry climate). Per event retention is also considered, and it is demonstrated that retention performance decreases significantly when high return period events are considered in isolation. For example, in Sheffield the median per-event retention is 1.00 (many small events), but the median retention for events exceeding a 1 in 1 yr return period threshold is only 0.10. The simulation tool also provides useful information about the likelihood of drought periods, for which irrigation may be required. A sensitivity study suggests that green roofs with reduced moisture-holding capacity and/or low evapotranspiration rates will tend to offer reduced levels of retention, whilst high moisture-holding capacity and low evapotranspiration rates offer the strongest drought resistance. PMID:24178313

  3. Validated thermal simulations of roof pond cooled residences in US climates

    SciTech Connect

    Clark, G.; Haves, P.; Vieira, R.; Loxsom, F.; Faultersack, J.; Doderer, E.

    1985-08-28

    This is the final report in a series of related reports which assess the ability of roof pond cooled residences to provide comfort and to save energy and peak in warm US climates. This report presents the results of new, validated simulations of wet and dry roof ''Skytherm'' type residences in 14 cities. The characteristics of the simulated residences and the thermal assumptions made are documented in detail. Significant thermal algorithms utilized are defined.

  4. Design, effectiveness, and construction of passive-thermal-control roofing shingles. Technical final report

    SciTech Connect

    Wolf, L. Jr.

    1982-09-01

    The concept of a passive thermal control roofing shingle, which is a shingle that reflects the summer sun and absorbs the winter sun, is discussed. Such a shingle will reduce summer cooling and winter heating costs and conserve electricity and natural gas or heating oil. Design calculations indicate that it is possible to design shingles for particular latitudes and styles of roof which absorb nearly all of the winter solar energy and reflect nearly all of the summer solar energy. Calculations of the energy savings and cost effectiveness of the passive thermal control roofing shingle indicate that it is most cost effective on all south facing pitched roofs regardless of heating fuel type, and on flat or east or west facing roofs that are heated with costly fuels such as electricity or heating oil. The shingle is most effective on poorly insulated structures. If the cost of the shingle is about one dollar per square foot it will be cost effective in these applications. Additional calculations demonstrate the feasibility of using the passive thermal control roofing shingle in conjunction with a heat pump to pump heat absorbed by the shingle into a well insulated structure. Construction of a variety of models of the passive thermal control roofing shingle illustrate numerous alternate methods of manufacture. A profile extruded, plastic, glazed shingle appears to be the most promising approach. Additionally, extruded plastic reflector assemblies of various kinds could be added to existing shingled roofs. Use of a glazed shingle can increase the effectiveness of the passive thermal control roofing shingle by reducing convective heat losses.

  5. Simulation model for the performance analysis of roof pond systems for heating and cooling

    SciTech Connect

    Tavana, M.; Kammerud, R.; Akbari, H.; Borgers, T.

    1980-06-01

    A detailed computer model has been developed for simulating the dynamic thermal behavior of roof pond systems. The model is composed of outer movable insulation, an optional evaporative water layer over water bags on steel decking, and an inner movable insulation. A control strategy for the movable insulations which provides near optimum thermal performance is included in the model. An hourly thermal balance analysis of the system is performed using theoretical and/or empirical expressions to determine the heat transfer coefficients for each of the surfaces in the model. The model has been used to study the effect on system thermal performance of (1) the R-value of both the top and bottom movable insulations; (2) the depth of the pond water, and (3) the depth of the evaporative layer. The heating and cooling potentials of the roof pond have also been investigated in four climates. The model was developed for incorporation into the public domain building energy analysis computer program BLAST.

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

    NASA Astrophysics Data System (ADS)

    Nagengast, Amy L.

    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.

  7. Field measurements of performance of roof solar collector

    Microsoft Academic Search

    Joseph Khedari; Weerapong Mansirisub; Sompong Chaima; Naris Pratinthong; Jongjit Hirunlabh

    2000-01-01

    To reduce the mechanical cooling energy cost of new housing built in a hot and humid region, the design should maximize the natural ventilation and minimize the fraction of sun energy absorbed by a dwelling. This objective is accomplished by using the roof structure to act as a solar collector. The roof solar collector design (RSC) used CPAC Monier concrete

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

    PubMed

    Klein, Petra M; Coffman, Reid

    2015-04-15

    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, 26 months 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

  9. Minimal watering regime impacts on desert adapted green roof plant performance

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  10. Design, effectiveness, and construction of passive-thermal-control roofing shingles. Technical final report

    Microsoft Academic Search

    L. Jr

    1982-01-01

    The concept of a passive thermal control roofing shingle, which is a shingle that reflects the summer sun and absorbs the winter sun, is discussed. Such a shingle will reduce summer cooling and winter heating costs and conserve electricity and natural gas or heating oil. Design calculations indicate that it is possible to design shingles for particular latitudes and styles

  11. Using Kinetic Models to Predict Thermal Degradation of Fire-Retardant-Treated Plywood Roof Sheathing

    Microsoft Academic Search

    Patricia K. Lebow; Jerrold E. Winandy

    Between 1985-1995 a substantial number of multifamily housing units in the Eastern and Southern U.S. experienced problems with thermally degraded fire-retardant-treated (FRT) plywood roof sheathing. A series of studies conducted at the USDA Forest Service, Forest Products Laboratory (FPL), examined the materials, chemical mechanisms, and process implications and has developed both practical and theoretical solutions for controlling strength effects during

  12. Performance and reliability of a 1kW amorphous silicon photovoltaic roofing system

    Microsoft Academic Search

    J. Adelstein; B. Sekulic

    2005-01-01

    The National Renewable Energy Laboratory (NREL) has been monitoring the performance of a 1- kWAC United Solar Systems Corporation (USSC) roofing system over the 6-year period from October 1998 to September 2004. This paper investigates the performance and reliability of this system. The annual degradation and seasonal fluctuation of the system's power output are calculated using the PVUSA power rating

  13. In-situ aging of roof systems containing polyisocyanurate roof insulation foamed with alternative blowing agents

    Microsoft Academic Search

    A. O. Desjarlais; J. E. Christian; R. S. Graves

    1993-01-01

    Experimental polyisocyanurate (PIR) foam roof insulations with permeable facers were installed in roofing systems and continuously monitored for thermal performance for four years. The foams were produced using a specific formulation that represented current technology in 1989 and were blown with CFC-11, HCFC-123, and HCFC-141b. These foams were installed in roof systems comprised of loosely-laid insulation boards covered by either

  14. Photovoltaic Roofs

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    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.

  15. Assessment of a fiber-optic distributed-temperature-sensing system to monitor the thermal dynamics of vegetated roof

    NASA Astrophysics Data System (ADS)

    Cousiño, J. A.; Hausner, M. B.; Victorero, F.; Bonilla, C.; Gironas, J. A.; Vera, S.; Bustamante, W.; Rojas, V.; Pasten, P.; Suarez, F. I.

    2014-12-01

    Vegetated (green) roofs include a growing media and vegetation layer, and offer a range of benefits such as the reduction of: the heat island effect, rooftop runoff peak flows, roof surface temperatures, energy used for cooling or heating buildings, and noise levels inside infrastructures. Vegetated roofs also offer aesthetic benefits and increase the biodiversity of the urban environment, and are increasingly used in sustainable urban development. Understanding the thermal dynamics of vegetated roofs will make it possible to improve their design and to better assess their impacts on energy efficiency. Here, we evaluate the first vertical high-resolution distributed-temperature-sensing (DTS) system installed in a vegetated roof. This system allows a continuous measurement of the thermal profile within a vegetated roof - going from the interior, upward through the drainage layers and soil substrate of the vegetated roof and ending in the air above the vegetation. Temperatures can be observed as frequently as every 30 s at a spatial resolution on the order of centimeters. This DTS system was installed in the "Laboratory of Vegetal Infrastructure of Buildings" (LIVE - its acronym in Spanish), located in the San Joaquín Campus of the Pontifical Catholic University, Santiago, Chile. The laboratory features 18 experimental modules to investigate different configurations of the vegetated roof layers. The LIVE was designed with the installation of the optical fibers in mind, and the DTS system allows simultaneous monitoring of three or four modules of the LIVE. In this work, we describe the design of this DTS deployment, the calibration metrics obtained using the software provided by the manufacturers, and other calibration algorithms previously developed. We compare the results obtained using single- and double-ended measurements, highlighting strengths and weaknesses of DTS methods. Finally, we present the observations obtained from this biophysical environment highlighting the features that are harder to observe using more traditional methods to measure temperature.

  16. Self drying roofs: What! No dripping!

    SciTech Connect

    Desjarlais, A.

    1995-12-31

    Many roofs are replaced because water accumulates in portions of the roofing system.These accumulations can cause dripping, accelerated membrane failure, poor thermal performance, the threat of structural decay, and the depreciation of building assets. Traditionally, the roofing industry has been concerned with controlling the inflow of water into the roof. An example of this strategy would be the development of a more reliable membrane. However, roof membranes inevitably leak. For this reason, the roof design strategy of the future must be concerned with controlling water outflow. The requirements of this type of roof system are described. Under normal operating conditions (no leaks), the total moisture content of a self-drying roof system shall not increase with time and condensation shall not occur under the membrane during winter uptake. Moisture vapor movement by convection must be eliminated and the flow of water by gravity through imperfections in the roof system must be controlled. After a leak has occurred, no condensation on the upper surface of the deck shall be tolerated and the water introduced by the leak must be dissipated to the building interior in a minimum amount of time. Finite difference computer modeling is used to demonstrate the effectiveness of the design. The impact of deck and insulation permeance, climate, leaks, and wintertime water uptake are simulated. A database of simulations is qualitatively described; this database will be used in future work to produce a simplified means of assessing the design parameters of a self-drying roof system.

  17. Advanced Energy Efficient Roof System

    SciTech Connect

    Jane Davidson

    2008-09-30

    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

  18. Performance of oil palm EFB fibre reinforced concrete roof slates

    Microsoft Academic Search

    J. Kaliwon; S. Sh Ahmad; A. Abdul Aziz

    2010-01-01

    Natural fibres such as wood and vegetable fibre offer many advantages such as renewability, recyclability low specific gravity and high specific strength. In Malaysia most of the studies only focused on producing EFB as MDF and pulp and paper products. This paper reviews the development of natural fibres for building material and discusses the performance of oil palm empty fruit

  19. Using remotely sensed thermal infrared multispectral data and thermal modeling to estimate lava tube roof thickness at Kilauea Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Resmini, Ronald G.

    2008-04-01

    Thermal Infrared Multispectral Scanner (TIMS) data are processed to yield surface temperatures over the lava tube system of Kilauea Volcano, Hawaii. TIMS is a 6-band airborne longwave infrared (8 ?m to 12 ?m) multispectral imaging system built and operated by the National Aeronautics and Space Administration (NASA). The data analyzed were collected in 1988 and are part of the Compiled Volcanology Data Set collection of Glaze et al., (1992). The primary goal of the analyses is to utilize the TIMS-derived surface temperatures to estimate lava tube roof thickness (LTRT). There is a paucity of studies that have utilized remotely-sensed imaging spectrometry data to estimate LTRT - a component important to understanding (and modeling) the thermal field of lava tube systems. Lava tube systems, in turn, are important to the emplacement of areally extensive lava flows on earth and on other planets. An in-scene atmospheric compensation method was applied to the data followed by a normalized emissivity method temperature/emissivity separation algorithm to obtain surface temperature. Surface temperature measurements are then compared to modeled temperatures in order to estimate lava tube roof thickness. Modeled temperatures are calculated via finite element analysis. Boundary conditions of the finite element models are derived from analyses of the TIMS data, independent knowledge of lava liquidus and solidus temperatures, and crustal heat-flow geophysical data. A TIMS plus modeling-derived LTRT agrees with estimates based on field observations. The TIMS data are described as are all processing and analysis methods. The thermal modeling is also described as is an effort to build a lookup table for LTRTs to be used in conjunction with surface temperature measurements. Archived data such as those exploited here provide a historical context particularly for terranes which may undergo relatively rapid change - such as the lava flow fields of Kilauea Volcano.

  20. The hydrological performance of a green roof test bed under UK climatic conditions

    NASA Astrophysics Data System (ADS)

    Stovin, Virginia; Vesuviano, Gianni; Kasmin, Hartini

    2012-01-01

    SummaryThis paper presents new rainfall and runoff data from a UK green roof test bed which has been collected almost-continuously over a 29-month period from 01/01/2007 to 31/05/2009. Overall, the monitoring period was fairly typical of the location's long-term climatic averages, although the data set includes some extreme events in June 2007, which were associated with serious flooding locally. To focus on the system's performance under rainfall events likely to be of interest from an urban drainage/stormwater management perspective, return period analysis has been applied to identify those storm events with a rainfall depth in excess of 5 mm and a return period greater than one year. According to these criteria, 22 significant events have been identified, of which 21 have reliable runoff records. Overall the roof provided 50.2% cumulative annual rainfall retention, with a total volumetric retention equivalent to 30% during the significant events. The annual performance figures are towards the lower end of a range of international data, probably reflecting the fact that rainfall depths may be higher and evapotranspiration rates lower than in some more continental climatic settings. The roof's finite retention depth means that the maximum possible retention percentage declines as storm depth increases, and retention varied from between 0 and 20 mm, or 0% to 100%. Although some attenuation and delay of peak runoff is generally observed (mean peak flow reduction of 60% for the 21 significant events), the irregularity of natural rainfall patterns, combined with the variable influence of detention storage in specific events, makes the identification of peak-to-peak lag times difficult and arguably meaningless. Regression analyses have been undertaken to explore the potential to predict the roof's hydrological performance as a function of storm characteristics. However, these are shown to have poor predictive capability, even for the system from which they were derived. Through a detailed examination of data from three contrasting events, it is argued that the inter-event processes are too complex to be captured by this type of modelling approach. Instead, an understanding of the hydrological processes affecting the flux of moisture into and out of the substrate is required to explain the observed runoff response. Locally-derived evapotranspiration rates and the roof's observed maximum retention capacity are utilised to provide pragmatic guidance on the retention performance to be expected in response to selected design events.

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

    PubMed

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

    2015-01-01

    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

  2. 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...

  3. Performance test of a low cost roof-mounted wind turbine

    NASA Astrophysics Data System (ADS)

    Figueroa-Espinoza, Bernardo; Quintal, Roberto; Gou, Clément; Aguilar, Alicia

    2013-11-01

    A low cost wind turbine was implemented based on the ideas put forward by Hugh Piggot in his book ``A wind turbine recipe book,'' where such device is developed using materials and manufacturing processes available (as much as possible) in developing countries or isolated communities. The wind turbine is to be mounted on a two stories building roof in a coastal zone of Mexico. The velocity profiles and turbulence intensities for typical wind conditions on top of the building roof were analyzed using numerical simulations (RANS) in order to locate the turbine hub above any recirculation and near the maximum average speed. The coefficient of performance is going to be evaluated experimentally by measuring the electrical power generation and wind characteristics that drive the wind turbine on the field. These experimental results will be applied on the improvement of the wind turbine design, as well as the validation of a numerical simulation model that couples the wind characteristics obtained through CFD with the Blade Element Method (BEM) and an electro-mechanical model of the turbine-shaft-generator ensemble. A low cost wind turbine was implemented based on the ideas put forward by Hugh Piggot in his book ``A wind turbine recipe book,'' where such device is developed using materials and manufacturing processes available (as much as possible) in developing countries or isolated communities. The wind turbine is to be mounted on a two stories building roof in a coastal zone of Mexico. The velocity profiles and turbulence intensities for typical wind conditions on top of the building roof were analyzed using numerical simulations (RANS) in order to locate the turbine hub above any recirculation and near the maximum average speed. The coefficient of performance is going to be evaluated experimentally by measuring the electrical power generation and wind characteristics that drive the wind turbine on the field. These experimental results will be applied on the improvement of the wind turbine design, as well as the validation of a numerical simulation model that couples the wind characteristics obtained through CFD with the Blade Element Method (BEM) and an electro-mechanical model of the turbine-shaft-generator ensemble. Special thanks to the Coordinación de Investigación Científica of the Universidad Michoacana de San Nicolás de Hidalgo for their support.

  4. The predicted impact of linear roof apertures on the energy performance of office buildings

    NASA Astrophysics Data System (ADS)

    Place, W.; Coutier, P.; Fontoynont, M.; Kammerud, R. C.; Andersson, B.; Bauman, F.; Carroll, W. L.; Howard, T. C.; Mertol, A.; Webster, T. L.

    1983-11-01

    The potential lighting electricity reductions and associated thermal impacts of replacing electric light with sunlight admitted through rooftop glazing on a single-story, prototypical office building were investigated. Experimental scale models were used to determine the fraction of the solar radiation entering the aperture which reaches the work plane as useful illumination. From this building energy analysis computer program was generated. Results of computer simulation indicate that a large fraction of the electricity consumed for lighting a single-story office building can be displaced using modest amounts of glazing in the roof. Smaller heating and cooling energy consumption reductions are possible from a daylighting system. The design implications of the results are discussed and future directions for the work are outlined.

  5. Effectiveness of Cool Roof Coatings with Ceramic Particles

    SciTech Connect

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

    2011-01-01

    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.

  6. Performance and Thermal Comfort

    Microsoft Academic Search

    I. D. GRIFFITHS; P. R. BOYCE

    1971-01-01

    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

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

    SciTech Connect

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

    1996-03-01

    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.

  8. IMPROVED ROOF STABILIZATION TECHNOLOGIES

    SciTech Connect

    M.A. Ebadian, Ph.D.

    1999-01-01

    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.

  9. In-situ aging of roof systems containing polyisocyanurate roof insulation foamed with alternative blowing agents

    SciTech Connect

    Desjarlais, A.O.; Christian, J.E.; Graves, R.S.

    1993-10-01

    Experimental polyisocyanurate (PIR) foam roof insulations with permeable facers were installed in roofing systems and continuously monitored for thermal performance for four years. The foams were produced using a specific formulation that represented current technology in 1989 and were blown with CFC-11, HCFC-123, and HCFC-141b. These foams were installed in roof systems comprised of loosely-laid insulation boards covered by either a loosely-laid single ply white or black membrane. The in-situ testing was carried out on an outdoor test facility, the Roof Thermal Research Apparatus (RTRA). Additional specimens of these foams were aged in the laboratory and periodically evaluated using laboratory measurement equipment. This paper summarizes the in-situ data compiled to date, compares these data with the laboratory results, and examines whether the proposed laboratory procedure for accelerating the aging of foams by the slicing and scaling method accurately predicts the aging characteristics of these materials installed in roof systems. These experiments are part of a joint industry/government project established to evaluate the technical viability of alternative HCFC blowing agents for rigid closed-cell polyisocyanurate foam roof insulations. Members of the project are the US Department of Energy (DOE)/Oak Ridge National Laboratory (ORNL), the US Environmental Protection Agency (EPA), the Society of the Plastics Industry-Polyurethane Division (SPI), the Polyisocyanurate Insulation Manufacturers Association (PIMA), and the National Roofing Contractors Association (NRCA).

  10. Measured and Simulated Performance of Reflective Roofing Systems in Residential Buildings

    Microsoft Academic Search

    Danny S. Parker; Yu Joe Huang; Steven J. Konopacki; Lisa M. Gartland; John R. Sherwin; Lixing Gu

    A series of experiments in Florida residences have measured the impact on space cooling of increasing roof solar reflectance. In tests on 11 homes with the roof color changed mid summer, the average cooling energy use was reduced by 19%. Measurements and infrared thermography showed that a significant part of the savings were due to interactions when the duct system

  11. Roofing: Workbook and Tests. Built-up Roofing.

    ERIC Educational Resources Information Center

    Klingensmith, Robert, Ed.

    Designed for use in roofing apprenticeship classes, this workbook contains eight units on skills used in built-up roofing, a listing of instructional materials, a glossary, and the text of Labor Code Article 30, Construction Safety Orders, "Roofing Operations and Equipment." Each instructional unit includes a listing of performance statements and…

  12. Thermal Performance Benchmarking (Presentation)

    SciTech Connect

    Moreno, G.

    2014-11-01

    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.

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

    Microsoft Academic Search

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

    2011-01-01

    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

  14. Thermal Performance of Uninsulated and Partially Filled Wall Cavities: Preprint

    SciTech Connect

    Ridouane, E. H.; Bianchi, M.

    2011-08-01

    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.

  15. The Rehab Guide: Roofs

    NSDL National Science Digital Library

    1999-01-01

    Anyone who has been on a roof on a hot day can attest to the difficulty of performing basic maintenance on that particular part of a building. Fortunately, this time-consuming process can be made simpler with this handy online guide to rehabbing a roof. Created by the PATH Group, this 99-page document covers major roofing systems, â??â?¦as well as protective strategies, energy and air filtration issues, roofing materials, and gutters and downspouts.â? Throughout the document, users can rely on drawings and photographs that illustrate various rehabbing techniques. Much is revealed here, including timely information on low-slope and metal roofing, along with suggestions on installing moisture barriers.

  16. Comparative Evaluation of the Impact of Roofing Systems on Residential Cooling Energy Demand in Florida

    Microsoft Academic Search

    Danny Parker; Jeffrey Sonne; John Sherwin

    Roof and attic thermal performance exert a powerful influence on cooling energy use in Florida homes. The Florida Power and Light Company and the Florida Solar Energy Center instrumented six side-by-side Habitat homes in Ft. Myers, Florida with identical floor plans and orientation, R-19 ceiling insulation, but with different roofing systems designed to reduce attic heat gain. A seventh house

  17. Computational analysis of the performance of a venturi-shaped roof for natural ventilation: Venturi-effect versus wind-blocking effect

    Microsoft Academic Search

    BJE Blocken; Hooff van TAJ; L. Aanen; B. Bronsema

    2011-01-01

    Computational Fluid Dynamics (CFD) is used to gain insight in the aerodynamic performance of a venturi-shaped roof (called VENTEC roof). The simulations are performed with the 3D steady Reynolds-averaged Navier–Stokes (RANS) equations and the Renormalisation Group k–? model. A detailed analysis is conducted of the influence of the so-called venturi-effect and the wind-blocking effect on the aerodynamic performance of the

  18. A Measurement Method of Actual Thermal Performance of Detached Houses 

    E-print Network

    Iwamae, A.; Nagai, H.; Miura, H.

    2004-01-01

    of the thermal performance of the envelope surfa as walls, roofs and windows, on the energy used by HVAC system is not so large in normal office buildings. Inthe detached houses, however, it is not too small to be neglected because of the relatively largeness.../K ----------------------------------------------------------------------------------------------------- Figure-1 shows the plan which is build in the backyard of TEPCO Laboratory in Kawasaki (near Tokyo). The floor of the house is specially insulated on both side of the concrete slab for the other particular measurement. We calculate the heat flux through...

  19. Development of a new roof bolt technology to improve gate-road performance

    SciTech Connect

    Caggiano, V.; Rauch, G.; Beck, K.-D.; Chen, J. [Hilti, Inc. (United States)

    2005-10-01

    Hilti has developed, in conjunction with Foundation Coal, a self-drilling bolt that cuts roof bolting times. The system uses a wet, self-drilling, hollow bolt technology with a self-contained resin cartridge. The resin is dispensed using an injection adapter that provides the high pressure water needed to dispense the resin. The OneStep roof bolt contains an axially shifting mixer that ensures the resin is properly mixed as it exits the water ports near the end of the bolt near the drill head. This eliminates the opportunity for plastic materials to interface between the strata and the bolt. In 2004 the OneStep Bolt was successfully installed in DSK's Prosper Haniel Colliery in Germany, achieving a 42% reduction in single-boom roof bolt cycle time and a 36% reduction in twin-boom roof bolt cycle time. Foundation Coal will be installing 2000 6 ft active bolts in one of the North Appalachian longwall locations. 1 fig.

  20. Sustainable roofs with real energy savings

    SciTech Connect

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

    1996-12-31

    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.

  1. System effects on the thermal aging of experimental polyisocyanurate roof insulation foamed with an alternative blowing agent

    Microsoft Academic Search

    A. O. Desjarlais; J. E Christian; R. L. Linkous

    1992-01-01

    Experimental polyisocyanurate foam roof insulation with 0.6mm thick permeable black facers blown with HCFC-141b installed on test roofs at the Oak Ridge National Laboratory for almost three years show various degrees of aging. Four roof systems are being monitored to determine the effect of system type on board aging. The four systems are comprised of a dry stack of insulation

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

    SciTech Connect

    Syd S. Peng

    2003-04-15

    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.

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

    SciTech Connect

    Syd S. Peng

    2003-01-15

    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.

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

    SciTech Connect

    Syd S. Peng

    2002-10-15

    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.

  5. Thermal Performance of Tropical Atrium

    NASA Astrophysics Data System (ADS)

    Baharvand, Mohammad; Bin Ahmad, Mohd Hamdan; Safikhan, Tabassom; Mirmomtaz, Sayyed Mohammad Mahdi

    2013-12-01

    Atrium is a popular architectural feature utilized widely by building designers and owners to bring various benefits such as adequate daylight, circulation spaces and surfaces for landscape applications. But atrium problems in tropical climates such as excessive daylight, glare and high temperature, which lead to increase building energy demand, have been reported. To avoid and reduce these unpleasant features, a side-lit atrium has been suggested. Although researchers proposed side-lit atrium to prevent common problems of atria, the lack of precedent research on this issue compels these authors to study atrium performance in hot and humid climate. So the research aims to examine two different atrium roof form types in terms of temperature and ventilation impacts in hot and humid climate of Malaysia using DesignBuilder as a simulation program. The results indicate lower temperature of side-lit model with better airflow pattern in comparison with top-lit model while the top-lit model provides higher air velocity at the air inlet and outlet.

  6. Quantification of Total Particulate Matter and Benzene-Soluble Fraction Inhalation Exposures in Roofing Workers Performing Tear-off Activities.

    PubMed

    Hill, Ronald H; Ferraro, John R; Dodson, James L; Hockman, Edwin L; McGovern, Amy E; Fayerweather, William E

    2015-07-01

    Asphalt shingle removal (tear-off) from roofs is a major job task for an estimated 174,000 roofers in the United States. However, a literature search showed that there are no published studies that characterize worker inhalation exposures to asphalt particulates during shingle tear-off. To begin to fill this gap, the present study of inhalation exposures of roofers performing asphalt shingle tear-off was undertaken. The airborne agents of interest were total particulate matter (TP) and organic particulates measured as the benzene-soluble fraction (BSF) of total particulate. The study's objectives were ?to measure the personal breathing zone (PBZ) exposures of roofing tear-off workers to BSF and TP; and ?to assess whether these PBZ exposures are different from ambient levels. Task-based PBZ samples (typical duration 1-5 hours) were collected during asphalt shingle tear-off from roofs near Houston, Texas and Denver, Colorado. Samples were analyzed for TP and BSF using National Institute of Occupational Safety and Health (NIOSH) Method 5042. As controls, area samples (typical duration 3-6 hours) were collected on the ground near the perimeter of the tear-off project Because of the presence of significant sources of inorganic particulates in the work environment, emphasis was placed on the BSF data. No BSF exposure higher than 0.25 mg/m3 was observed, and 69% of the PBZ samples were below the limit of detection (LOD). Due to unforeseen confounding, however, statistical comparisons of on-the-roof PBZ samples with on-the-ground area samples posed some special challenges. This confounding grew out of the interaction of three factors: ?statistical censoring from the left; ?the strong inverse correlation between LOD concentration and sampling duration; and ?variation in sampling durations between on-the-ground area samples and on-the-roof PBZ samples. A general linear model analysis of variance (GLM-ANOVA) was applied to help address the confounding. The results of this analysis indicate that personal sample BSF results were not statistically significantly different from the background/area samples. PMID:26083058

  7. Window performance for human thermal comfort

    E-print Network

    Huizenga, C; Zhang, H.; Mattelaer, P.; Yu, T.; Arens, Edward A; Lyons, P.

    2006-01-01

    Thermal Performance of Chemically Deposited Solar Control Coatings”.Thermal Response of Laminated Glass with Solar Control Coating”.Thermal Performance of an Architectural Window with Chemically Deposited SnS-CuxS Solar Control Coating”.

  8. Roofing panels

    Microsoft Academic Search

    Brill-edwards

    1983-01-01

    A roofing panel of glass-reinforced plastic (G.R.P.) or sheet metal is stiffened by longitudinal beams on its underside to span one pitch of a pitched roof from eaves to ridge. It has an outer skin and an inner impervious liner spaced therefrom and supported on the stiffening beams so as to form a tunnel open at both ends and extending

  9. EURECA thermal control flight performance

    Microsoft Academic Search

    Wolfgang Hahn; Giuseppe D. Racca; Angus Blackwood

    1993-01-01

    The European Retrievablle Carrier (EURCA) at the time of writing is completeing its mission in low Earth orbit, waiting for the retrieval launch of the Shuttle STS-57. EURCA has completed already to a large extent its scientific operations and has undergone to a series of various orbital phases. The thermal control performances are addressed in this paper on the basis

  10. Joint Industry/Government Research Project: Comparison of thermal aging for roof exposures and thin-specimens of experimental polyisocyanurate insulation foamed with alternative blowing agents

    SciTech Connect

    Graves, R.S.; Christian, J.E.; McElroy, D.L.

    1991-01-01

    This paper reports apparent thermal conductivity (k) values from field exposures and laboratory aging of a set of industry-produced, experimental polyisocyanurate (PIR) laminated boardstock foamed with hydrochlorofluorocarbons (HCFCs) as alternative to chlorofluorocarbons (CFCs). The k-values were determined from 0 to 50{degree}C using techniques that meet ASTM C 1114 (Thin Heater Apparatus) and ASTM C 518 (Heat Flow Meter Apparatus). The increase in k observed for field exposure in the ORNL Roof Thermal Research Apparatus (RTRA) was confirmed by independent laboratory tests. The observed laboratory increase in k was about the same, between 17 and 22%, for all three blowing agent foams for a 450 day field exposure in the RTRA. Thin specimens were planed from the industry-produced boardstock foams and aged at 24 and 65{degree}C for up to 460 days. The foams blown with alternative blowing agents exhibited long-term k-values 7 to 15% above those for CFC foams under similar conditions. Field exposures were conducted on specimens under single ply EPDM membranes in the RTRA for over 680 days. Hourly averages of panel temperature and heat flux were analyzed to obtain k as a function of mean insulation temperature on a week-by-week basis. The k-values derived from the field data provided effective diffusion coefficients for air in the foam, which were within 7% of those obtained from the thin-specimen aging procedure at 24%C except for one sample. The relative performance of test specimens of HCFC-141b under a black and under a white membrane is reported, and data suggest that differences are relatively small. 26 refs., 10 figs., 8 tabs.

  11. New configurations of a roof solar collector maximizing natural ventilation

    Microsoft Academic Search

    Jongjit Hirunlabh; Sopin Wachirapuwadon; Naris Pratinthong; Joseph Khedari

    2001-01-01

    The paper discusses the performance of a construction element: the Roof Solar Collector (RSC) with regard to maximizing the rate of induced natural ventilation, which contributes to the improvement of indoor thermal comfort of houses. The RSC configuration was made by using modern materials: CPAC monier concrete tiles on the outside and gypsum board on the inside. The comparison of

  12. Effectiveness of Cool Roof Coatings with Ceramic Particles

    Microsoft Academic Search

    Ellen G Brehob; Andre Omer Desjarlais; Jerald Allen Atchley

    2011-01-01

    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

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

    SciTech Connect

    Syd S. Peng

    2005-10-01

    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.

  14. Hydrological performance of extensive green roofs in New York City: observations and multi-year modeling of three full-scale systems

    NASA Astrophysics Data System (ADS)

    Carson, T. B.; Marasco, D. E.; Culligan, P. J.; McGillis, W. R.

    2013-06-01

    Green roofs can be an attractive strategy for adding perviousness in dense urban environments where rooftops are a high fraction of the impervious land area. As a result, green roofs are being increasingly implemented as part of urban stormwater management plans in cities around the world. In this study, three full-scale green roofs in New York City (NYC) were monitored, representing the three extensive green roof types most commonly constructed: (1) a vegetated mat system installed on a Columbia University residential building, referred to as W118; (2) a built-in-place system installed on the United States Postal Service (USPS) Morgan general mail facility; and (3) a modular tray system installed on the ConEdison (ConEd) Learning Center. Continuous rainfall and runoff data were collected from each green roof between June 2011 and June 2012, resulting in 243 storm events suitable for analysis ranging from 0.25 to 180 mm in depth. Over the monitoring period the W118, USPS, and ConEd roofs retained 36%, 47%, and 61% of the total rainfall respectively. Rainfall attenuation of individual storm events ranged from 3 to 100% for W118, 9 to 100% for USPS, and 20 to 100% for ConEd, where, generally, as total rainfall increased the per cent of rainfall attenuation decreased. Seasonal retention behavior also displayed event size dependence. For events of 10-40 mm rainfall depth, median retention was highest in the summer and lowest in the winter, whereas median retention for events of 0-10 mm and 40 +mm rainfall depth did not conform to this expectation. Given the significant influence of event size on attenuation, the total per cent retention during a given monitoring period might not be indicative of annual rooftop retention if the distribution of observed event sizes varies from characteristic annual rainfall. To account for this, the 12 months of monitoring data were used to develop a characteristic runoff equation (CRE), relating runoff depth and event size, for each green roof. When applied to Central Park, NYC precipitation records from 1971 to 2010, the CRE models estimated total rainfall retention over the 40 year period to be 45%, 53%, and 58% for the W118, USPS, and ConEd green roofs respectively. Differences between the observed and modeled rainfall retention for W118 and USPS were primarily due to an abnormally high frequency of large events, 50 mm of rainfall or more, during the monitoring period compared to historic precipitation patterns. The multi-year retention rates are a more reliable estimate of annual rainfall capture and highlight the importance of long-term evaluations when reporting green roof performance.

  15. Application of passive cooling systems in the hot and humid climate: The case study of solar chimney and wetted roof in Thailand

    Microsoft Academic Search

    Sudaporn Chungloo; Bundit Limmeechokchai

    2006-01-01

    The thermal performance of two passive cooling systems under hot and humid climate condition is experimentally investigated. The experimental results were obtained from a test cell and a controlled cell with identical walls but different roof configurations. The passive cooling systems applied to the test cell are solar chimney and water spraying on roof. The experimental results obtained from the

  16. Green roofs: potential at LANL

    SciTech Connect

    Pacheco, Elena M [Los Alamos National Laboratory

    2009-01-01

    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.

  17. Rain on the Roof-Evaporative Spray Roof Cooling

    E-print Network

    Bachman, L. R.

    1985-01-01

    This paper describes evaporative spray roof cooling systems, their components, performance and applications in various climates and building types. The evolution of this indirect evaporative cooling technique is discussed. Psychrometric and sol...

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

    SciTech Connect

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

    1998-01-01

    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.

  19. Field experience and dew point studies of a retrofitted roof

    SciTech Connect

    Carlson, A.R. [Univ. of Alaska, Fairbanks, AK (United States). Cooperative Extension Service

    1997-11-01

    A symposium on insulating materials would not be complete without discussing the effect of the thermal and vapor performance on potential condensation problems in insulated assemblies. Retrofitting the top of an existing insulated roof with an impermeable rigid or foamed insulation can lead to serious condensation-related maintenance problems. Dew point studies in Alaska indicate that the thermal resistance of retrofitted assemblies should be at least two times greater than the existing insulated wall, or roof to avoid condensation in the cavity, depending on local heating degree days. Further, an exterior impervious insulated wall or roof assembly should be provided with some type of natural venting to relieve vapor pressure and allow excess condensate to drain and evaporate. Unfortunately, most condensation problems do not become apparent for 5 to 10 years, long after the one year warranty is null and void. A computer spreadsheet will be presented that simulates dew point conditions in an insulated roof assembly to determine the proper selection and placement of the vapor retarder, insulation, and ventilation of the exterior skin to prevent further deterioration of the roof. This necessitated the computation and tabulation of surface temperatures, dew point temperatures, vapor pressures and relative humidities at various structural components of the insulated assemblies, particularly near the outer skin.

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

    SciTech Connect

    Syd S. Peng

    2001-10-15

    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.

  1. How phase change materials affect thermal performance: hollow bricks

    Microsoft Academic Search

    Chi-ming Lai; Che-ming Chiang

    2006-01-01

    The enhancement of rooftop thermal-insulation capability is a key issue in energy conservation in hot and humid climates, where flat roofs receive the greatest solar heat gain. During the process of melting or solidification, a phase change material (PCM) can effectively release or store a great amount of latent heat. As a result, PCM has often been applied for the

  2. Plant functional traits predict green roof ecosystem services.

    PubMed

    Lundholm, Jeremy; Tran, Stephanie; Gebert, Luke

    2015-02-17

    Plants make important contributions to the services provided by engineered ecosystems such as green roofs. Ecologists use plant species traits as generic predictors of geographical distribution, interactions with other species, and ecosystem functioning, but this approach has been little used to optimize engineered ecosystems. Four plant species traits (height, individual leaf area, specific leaf area, and leaf dry matter content) were evaluated as predictors of ecosystem properties and services in a modular green roof system planted with 21 species. Six indicators of ecosystem services, incorporating thermal, hydrological, water quality, and carbon sequestration functions, were predicted by the four plant traits directly or indirectly via their effects on aggregate ecosystem properties, including canopy density and albedo. Species average height and specific leaf area were the most useful traits, predicting several services via effects on canopy density or growth rate. This study demonstrates that easily measured plant traits can be used to select species to optimize green roof performance across multiple key services. PMID:25599106

  3. Hydrological Response of Sedum-Moss Roof

    NASA Astrophysics Data System (ADS)

    Bengtsson, L.

    2004-12-01

    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.

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

    SciTech Connect

    Syd S. Peng

    2003-07-15

    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.

  5. Thermal Performance Challenges from Silicon to Systems

    Microsoft Academic Search

    Ram Viswanath; Vijay Wakharkar; Vassou Lebonheur

    2000-01-01

    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

  6. Advanced Energy Efficient Roof System

    Microsoft Academic Search

    Jane Davidson

    2008-01-01

    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

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

    SciTech Connect

    Syd S. Peng

    2002-04-15

    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.

  8. Steel-framed buildings: Impacts of wall detail configurations on the whole wall thermal performance

    SciTech Connect

    Kosny, J.; Desjarlais, A.O.; Christian, J.E.

    1998-06-01

    The main objective of this paper is the influence of architectural wall details on the whole wall thermal performance. Whole wall thermal performance analysis was performed for six light gage steel-framed wall systems (some with wood components). For each wall system, all wall details were simulated using calibrated 3-D finite difference computer modeling. The thermal performance of the six steel-framed wall systems included various system details and the whole wall system thermal performance for a typical single-story ranch house. Currently, predicted heat losses through building walls are typically based on measurements of the wall system clear wall area using test methods such as ASTM C 236 or are calculated by one of the procedures recommended in the ASHRAE Handbook of Fundamentals that often is carried out for the clear wall area exclusively. In this paper, clear wall area is defined as the part of the wall system that is free of thermal anomalies due to building envelope details or thermally unaffected by intersections with other surfaces of the building envelope. Clear wall experiments or calculations normally do not include the effects of building envelope details such as corners, window and door openings, and structural intersections with roofs, floors, ceilings, and other walls. In steel-framed wall systems, these details typically consist of much more structural components than the clear wall. For this situation, the thermal properties measured or calculated for the clear wall area do not adequately represent the total wall system thermal performance. Factors that would impact the ability of today`s standard practice to accurately predict the total wall system thermal performance are the accuracy of the calculation methods, the area of the total wall that is clear wall, and the quantity and thermal performance of the various wall system details.

  9. Cool roof Q+A 011.doc 29 July 2009 Cool Roof Q & A (draft)

    E-print Network

    that of a comparable standard product. For example, the afternoon surface temperature of a specially designed "cool thermal radiation. An easy way to judge the coolness of a roof is to compare its surface temperature, and a surface temperature elevation (surface temperature ­ outside air temperature) T of 69°F [38 K]. A roof

  10. Thermal performance and heat transport in aquifer thermal energy storage

    NASA Astrophysics Data System (ADS)

    Sommer, W. T.; Doornenbal, P. J.; Drijver, B. C.; van Gaans, P. F. M.; Leusbrock, I.; Grotenhuis, J. T. C.; Rijnaarts, H. H. M.

    2013-11-01

    Aquifer thermal energy storage (ATES) is used for seasonal storage of large quantities of thermal energy. Due to the increasing demand for sustainable energy, the number of ATES systems has increased rapidly, which has raised questions on the effect of ATES systems on their surroundings as well as their thermal performance. Furthermore, the increasing density of systems generates concern regarding thermal interference between the wells of one system and between neighboring systems. An assessment is made of (1) the thermal storage performance, and (2) the heat transport around the wells of an existing ATES system in the Netherlands. Reconstruction of flow rates and injection and extraction temperatures from hourly logs of operational data from 2005 to 2012 show that the average thermal recovery is 82 % for cold storage and 68 % for heat storage. Subsurface heat transport is monitored using distributed temperature sensing. Although the measurements reveal unequal distribution of flow rate over different parts of the well screen and preferential flow due to aquifer heterogeneity, sufficient well spacing has avoided thermal interference. However, oversizing of well spacing may limit the number of systems that can be realized in an area and lower the potential of ATES.

  11. Which Roof Is Tops?

    NSDL National Science Digital Library

    2014-09-18

    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.

  12. Thermal performance of automotive aluminium plate radiator

    Microsoft Academic Search

    A. Witry; M. H. Al-Hajeri; Ali A. Bondok

    2005-01-01

    The thermal performance of an automotive radiator plays an important role in the performance of an automobile’s cooling system and all other associated systems. For a number of years, this component has suffered from little attention with very little changing in its manufacturing cost, operation and geometry. As opposed to the old tubular heat exchanger configurations used in automotive radiators,

  13. Green roof stormwater retention: effects of roof surface, slope, and media depth.

    PubMed

    VanWoert, Nicholaus D; Rowe, D Bradley; Andresen, Jeffrey A; Rugh, Clayton L; Fernandez, R Thomas; Xiao, Lan

    2005-01-01

    Urban areas generate considerably more stormwater runoff than natural areas of the same size due to a greater percentage of impervious surfaces that impede water infiltration. Roof surfaces account for a large portion of this impervious cover. Establishing vegetation on rooftops, known as green roofs, is one method of recovering lost green space that can aid in mitigating stormwater runoff. Two studies were performed using several roof platforms to quantify the effects of various treatments on stormwater retention. The first study used three different roof surface treatments to quantify differences in stormwater retention of a standard commercial roof with gravel ballast, an extensive green roof system without vegetation, and a typical extensive green roof with vegetation. Overall, mean percent rainfall retention ranged from 48.7% (gravel) to 82.8% (vegetated). The second study tested the influence of roof slope (2 and 6.5%) and green roof media depth (2.5, 4.0, and 6.0 cm) on stormwater retention. For all combined rain events, platforms at 2% slope with a 4-cm media depth had the greatest mean retention, 87%, although the difference from the other treatments was minimal. The combination of reduced slope and deeper media clearly reduced the total quantity of runoff. For both studies, vegetated green roof systems not only reduced the amount of stormwater runoff, they also extended its duration over a period of time beyond the actual rain event. PMID:15888889

  14. Thermal control surfaces experiment flight system performance

    NASA Technical Reports Server (NTRS)

    Wilkes, Donald R.; Hummer, Leigh L.; Zwiener, James M.

    1991-01-01

    The Thermal Control Surfaces Experiment (TCSE) is the most complex system, other than the LDEF, retrieved after long term space exposure. The TCSE is a microcosm of complex electro-optical payloads being developed and flow by NASA and the DoD including SDI. The objective of TCSE was to determine the effects of the near-Earth orbital environment and the LDEF induced environment on spacecraft thermal control surfaces. The TCSE was a comprehensive experiment that combined in-space measurements with extensive post flight analyses of thermal control surfaces to determine the effects of exposure to the low earth orbit space environment. The TCSE was the first space experiment to measure the optical properties of thermal control surfaces the way they are routinely measured in a lab. The performance of the TCSE confirms that low cost, complex experiment packages can be developed that perform well in space.

  15. Thermal control surfaces experiment flight system performance

    NASA Technical Reports Server (NTRS)

    Wilkes, Donald R.; Hummer, Leigh L.; Zwiener, James M.

    1992-01-01

    The Thermal Control Surfaces Experiment (TCSE) is the most complex system retrieved after long term space exposure. The TCSE is a microcosm of complex electro-optical payloads being developed and flown. The objective of the TCSE on the LDEF was to determine the effects of the near-Earth orbital environment and the LDEF induced environment on spacecraft thermal control surfaces. The TCSE was a comprehensive experiment that combined in-space measurements with extensive post-flight analyses of thermal control surfaces to determine the effects of exposure to the low Earth orbit space environment. The TCSE was the first space experiment to measure the optical properties of thermal control surfaces the way they are routinely measured in the lab. The performance of the TCSE flight system on the LDEF was excellent.

  16. Thermal Performance Testing of Cryogenic Insulation Systems

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    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.

  17. Spacelab carrier complement thermal design and performance

    NASA Technical Reports Server (NTRS)

    Bancroft, S.; Key, R.; Kittredge, S.

    1992-01-01

    The present discussion of the Spacelab carrier complement, which encompasses a Module Carrier, a Module-Pallet Carrier, and a Multiplexer/Demultiplexer Pallet, gives attention to both active and passive thermal performance capabilities, and presents ground testing and analytical results obtained to date. An account is given of the prospective use of a Spacelab Multipurpose Experiment Support Structure.

  18. Experience with the use of mullite-corundum refractories in the roofs of electric-steel furnaces

    SciTech Connect

    Ustichenko, V.A.; Oleksienko, A.Ya.; Stepanova, V.P.; Sizov, V.I.; Tunaeva, T.A.

    1986-11-01

    The authors assess the performance of a mullite-corundum refractory in the roof of an arc furnace on the basis of its pore structure, temperature resistance, scaling, thermal conductivity, compression strength, deformability, and its contribution to the overall thermal efficiency and reduced electrical power consumption of the furnace. Comparative tests are run against periclase-chromite refractories. The mullite-corundum versions are found to possess superior thermal resistance and service life.

  19. The effect of air infiltration on the thermal performance of a small metal-framed assembly

    SciTech Connect

    Petrie, T.W.; Christian, J.E.; Childs, P.W. [Oak Ridge National Lab., TN (United States). Energy Div.

    1997-03-01

    Innovative construction materials and systems have generated a need for laboratory scale tests to quantify the effect of air leakage on thermal and moisture performance of building assemblies. Some construction materials and systems are inherently more air tight than others. It is desirable to do laboratory scale measurements on alternative systems so as to rank them with respect to air tightness just as they can be ranked with respect to system R-value. Participants in summer 1995 and 1996 workshops for elementary and secondary school science teachers in the Buildings Technology Center (BTC) at the Oak Ridge National Laboratory sought a way to illustrate basic principles of building science in the classroom. They decided to build a small metal-framed assembly with internal volume of 44 ft{sup 3} (1.25 m{sup 3}) and removable wall sheathing. The assembly included a door and window. Although the door and window were made from 4-in. (10.2-cm) thick foam insulation, the requisite framing for them detracted from the thermal performance of the walls and occupied a disproportionately large fraction of the wall area. The floor and roof of the assembly were also well-insulated so that the walls dominated the conduction heat loss through the assembly. The plan was to test thermal performance of the assembly with the sheathing and without it. Thereby the teachers hoped to show the effects of thermal bridges with metal framing as well as practical yet insightful way to reduce their effects.

  20. Thermal performance of cold storage in thermal battery for air conditioning

    Microsoft Academic Search

    Jen-Jie Chieh; Shu-Ju Lin; Sih-Li Chen

    2004-01-01

    This article studies, experimentally and theoretically, the thermal performance of cold storage in thermal battery for air conditioning. Thermal battery utilizes the superior heat transfer characteristics of heat pipe and eliminates drawbacks found in the conventional thermal storage tank. Experimental investigations are first conducted to study the cold storage thermal performance in two experimental systems: the ratio of distance between

  1. Library of Science & Medicine Roof Replacement and Related Work December 11, 2000 DSR # 0059-00 BSH

    E-print Network

    authorities. They do not include contract enforcement activities performed by the Architect, Owner or Owner certified to at least Level 2 in the Thermal/Infrared test method, in accordance with American Society and reported in accordance with ASTM C- 1153; "Standard Practice for the Location of Wet Insulation in Roofing

  2. Why Cool Roofs?

    ScienceCinema

    Chu, Steven

    2013-05-29

    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.

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

    NASA Technical Reports Server (NTRS)

    Boeer, K. W.

    1975-01-01

    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.

  4. Protected Membrane Roofs: A Sustainable Roofing Solution.

    ERIC Educational Resources Information Center

    Roodvoets, David L.

    2003-01-01

    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…

  5. Computing Thermal Performances Of Shafts And Bearings

    NASA Technical Reports Server (NTRS)

    Woods, Claudia M.

    1992-01-01

    SHABERTH computer program developed to predict steady-state and transient thermal performance of multi-bearing shaft system operating with either wet or dry friction. Calculates loads, torques, temperatures, and fatigue lives for ball and/or roller bearings on single shaft. Enables study of many causes of instabilities in bearings. Also provides for analysis of reaction of system to termination of supply of lubricant to bearings and other lubricated mechanical elements. Valuable software tool in design and analysis of shaft bearing systems. Written in FORTRAN IV.

  6. Solar heating shingle roof structure

    Microsoft Academic Search

    Straza

    1984-01-01

    A solar heating roof shingle roof structure which combines the functions of a roof and a fluid conducting solar heating panel. Each shingle is a hollow body of the general size and configuration of a conventional shingle, and is provided with a fluid inlet and a fluid outlet. Shingles are assembled in a normal overlapping array to cover a roof

  7. Seismic Response of Green Roofs

    Microsoft Academic Search

    M. O. Carmody; M. Jasarevic; P. Omenzetter; G. C. Clifton; E. A. Fassman

    Green roofs consist of vegetation with a light-weight substrate planted over a drainage layer and waterproof membrane. The green roof retains rainwater in the plants and substrate and releases the water through evapotranspiration and some surface drainage. This research explored the green roof's ability to resist seismic forces and the potential for the green roof to be used as an

  8. Green Roofs for Stormwater Management

    EPA Science Inventory

    This project evaluated green roofs as a stormwater management tool. Results indicate that the green roofs are capable of removing 40% of the annual rainfall volume from a roof through retention and evapotranspiration. Rainfall not retained by green roofs is detained, effectively...

  9. Thermal Performance of the XRS Helium Insert

    NASA Technical Reports Server (NTRS)

    Breon, Susan R.; DiPirro, Michael J.; Tuttle, James G.; Shirron, Peter J.; Warner, Brent A.; Boyle, Robert F.; Canavan, Edgar R.

    1999-01-01

    The X-Ray Spectrometer (XRS) is an instrument on the Japanese Astro-E satellite, scheduled for launch early in the year 2000. The XRS Helium Insert comprises a superfluid helium cryostat, an Adiabatic Demagnetization Refrigerator (ADR), and the XRS calorimeters with their cold electronics. The calorimeters are capable of detecting X-rays over the energy range 0.1 to 10 keV with a resolution of 12 eV. The Helium Insert completed its performance and verification testing at Goddard in January 1999. It was shipped to Japan, where it has been integrated with the neon dewar built by Sumitomo Heavy Industries. The Helium Insert was given a challenging lifetime requirement of 2.0 years with a goal of 2.5 years. Based on the results of the thermal performance tests, the predicted on-orbit lifetime is 2.6 years with a margin of 30%. This is the result of both higher efficiency in the ADR cycle and the low temperature top-off, more than compensating for an increase in the parasitic heat load. This paper presents a summary of the key design features and the results of the thermal testing of the XRS Helium Insert.

  10. Low-sloped roofing research plan. Final report

    Microsoft Academic Search

    W. C. Cullen; W. J. Jr Rossiter; R. G. Mathey; J. R. Clifton

    1983-01-01

    This report presents a long-range plan for roofing research. The plan was developed in response to a need for roofing research addressing major materials problems and changes in low-sloped roofing materials technology. The intent of the plan is to establish the technical basis for developing standards and minimum levels of performance to assist in the selection of cost-effective and durable

  11. Roof bolt bond tester

    SciTech Connect

    Not Available

    1982-01-01

    An intrinsically safe, electronic instrument has been developed that determines the holding quality of a fully grouted roof bolt by testing the integrity of the resin bond to both the bolt and to the surrounding rock.

  12. 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.

  13. Evaluation of heat flux reduction provided by the use of radiant barriers in clay tile roofs

    Microsoft Academic Search

    Caren Michels; Roberto Lamberts; Saulo Güths

    2008-01-01

    In Brazilian towns and cities the greatest thermal gain occurs through the roof of single-storey buildings. In this regard, the use of thermal radiation barriers has the function of minimizing the heat flux through the roof. Even though the use of this type of thermal insulation has increased in recent years; there are still no technical standards which address the

  14. Fourier analysis of conductive heat transfer for glazed roofing materials

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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.

  15. Microinverter Thermal Performance in the Real-World: Measurements and Modeling

    PubMed Central

    Hossain, Mohammad Akram; Xu, Yifan; Peshek, Timothy J.; Ji, Liang; Abramson, Alexis R.; French, Roger H.

    2015-01-01

    Real-world performance, durability and reliability of microinverters are critical concerns for microinverter-equipped photovoltaic systems. We conducted a data-driven study of the thermal performance of 24 new microinverters (Enphase M215) connected to 8 different brands of PV modules on dual-axis trackers at the Solar Durability and Lifetime Extension (SDLE) SunFarm at Case Western Reserve University, based on minute by minute power and thermal data from the microinverters and PV modules along with insolation and environmental data from July through October 2013. The analysis shows the strengths of the associations of microinverter temperature with ambient temperature, PV module temperature, irradiance and AC power of the PV systems. The importance of the covariates are rank ordered. A multiple regression model was developed and tested based on stable solar noon-time data, which gives both an overall function that predicts the temperature of microinverters under typical local conditions, and coefficients adjustments reecting refined prediction of the microinverter temperature connected to the 8 brands of PV modules in the study. The model allows for prediction of internal temperature for the Enphase M215 given similar climatic condition and can be expanded to predict microinverter temperature in fixed-rack and roof-top PV systems. This study is foundational in that similar models built on later stage data in the life of a device could reveal potential influencing factors in performance degradation. PMID:26147339

  16. 30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...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...

  17. 30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...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...

  18. 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

  19. Thermal evaluation of advanced solar dynamic heat receiver performance

    NASA Astrophysics Data System (ADS)

    Crane, Roger A.

    1989-03-01

    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.

  20. Thermal Performance Testing Of Cryogenic Piping Systems

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    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.

  1. Space Station Freedom active thermal control system performance verification

    Microsoft Academic Search

    John Goepp

    1991-01-01

    Issues associated with the application of two-phase thermal control technology to the Space Station Freedom (SSF) configuration are discussed. It is noted that the adoption of pumped two-phase thermal control technology necessitates the use of new verification strategies. A testing strategy is proposed for issue resolution and system performance verification. The architecture of the active thermal control system and the

  2. Magellan spacecraft thermal control system design and performance

    Microsoft Academic Search

    James C. Neuman; Joseph A. Buescher; Gregory J. Esterl

    1993-01-01

    A thermal control system of the Magellan spacecraft launched on May 4, 1989 to perform radar mapping and other science experiments is described. The thermal control system design required sustained operations near Venus in a three-axis stabilized spacecraft. It is concluded that, despite the constraints imposed by Magellan's thermal degradation, the primary mission goal of mapping at least 70 percent

  3. Solar heating shingle roof structure

    Microsoft Academic Search

    Straza

    1981-01-01

    A solar heating roof shingle roof structure which combines the functions of a roof and a fluid conducting solar heating panel. Each shingle is a hollow body of the general size and configuration of a conventional shingle, and is provided with a fluid inlet socket at the upper end and a fluid outlet plug at the lower end with a

  4. High-Tech Roof Management.

    ERIC Educational Resources Information Center

    Benzie, Tim

    1997-01-01

    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)

  5. Thermal control surfaces experiment flight system performance

    Microsoft Academic Search

    Donald R. Wilkes; Leigh L. Hummer; James M. Zwiener

    1992-01-01

    The Thermal Control Surfaces Experiment (TCSE) is the most complex system retrieved after long term space exposure. The TCSE is a microcosm of complex electro-optical payloads being developed and flown. The objective of the TCSE on the LDEF was to determine the effects of the near-Earth orbital environment and the LDEF induced environment on spacecraft thermal control surfaces. The TCSE

  6. Electrical, Frequency and Thermal Measurement and Modelling of Supercapacitor Performance

    E-print Network

    Paris-Sud XI, Université de

    Electrical, Frequency and Thermal Measurement and Modelling of Supercapacitor Performance Yasser--This paper presents an evaluation of commercial supercapacitors performance (ESR, C, self-discharge, Pmax, Emax, coulumbic efficiency, etc), under different conditions. Characterization of supercapacitor

  7. Mine roof drill bits that save money

    SciTech Connect

    Ford, L.M.

    1982-04-01

    Sandia National Laboratories, Albuquerque, NM, has developed advanced technology roof bolt drill bits which have demonstrated longer life, higher penetration rates at lower thrust and torque, and lower specific energy than conventional roof bolt drill bits. This is achieved through use of advanced technology cutting materials and novel bit body designs. These bits have received extensive laboratory and mine testing. Their performance has been evaluated and estimates of their value in reducing coal production costs have been made. The work was sponsored by the United States Department of Energy.

  8. Cryogenic thermal distortion performance characterization for the JWST ISIM structure

    Microsoft Academic Search

    John Johnston; Emmanuel Cofie; Jason Hylan; Raymond Ohl; Maria Nowak; Douglas McGuffey; James Pontius; Eric Johnson

    2011-01-01

    The James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Structure is a precision optical metering structure for the JWST science instruments. Optomechanical performance requirements place stringent limits on the allowable thermal distortion of the metering structure between ambient and cryogenic operating temperature (~35 K). This paper focuses on thermal distortion testing and successful verification of performance requirements for

  9. Solar heating shingle roof structure

    SciTech Connect

    Straza, G.T.

    1984-01-31

    A solar heating roof shingle roof structure which combines the functions of a roof and a fluid conducting solar heating panel. Each shingle is a hollow body of the general size and configuration of a conventional shingle, and is provided with a fluid inlet and a fluid outlet. Shingles are assembled in a normal overlapping array to cover a roof structure, with interconnections between the inlets and outlets of successive shingles to provide a fluid path through the complete array. An inlet manifold is contained in a cap used at the peak of the roof and an outlet manifold is connected to the lowest row of shingles.

  10. Performance of a solar-thermal collector

    NASA Technical Reports Server (NTRS)

    Higa, W. H.

    1975-01-01

    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.

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

    SciTech Connect

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

    2013-04-01

    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.

  12. Investigation of the Mechanical Performance of Compliant Thermal Barriers

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

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

    PubMed

    Ge, Zhiwei; Ye, Feng; Ding, Yulong

    2014-05-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are investigated. The ceramic supporting material is essential for preventing salt leakage and hence provides a solution to the chemical incompatibility issue. The use of graphite gives a significant enhancement on the thermal conductivity of the composite. Analyses suggest that the experimentally observed microstructural development of the composite is associated with the wettability of the salt on the ceramic substrate and that on the thermal conduction enhancer. PMID:24591286

  14. Extending Our Understanding of Compliant Thermal Barrier Performance

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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.

  15. TASK 2.5.7 FIELD EXPERIMENTS TO EVALUATE COOL-COLORED ROOFING

    SciTech Connect

    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

    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

  16. Advanced Low Conductivity Thermal Barrier Coatings: Performance and Future Directions

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2008-01-01

    Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and performance will be emphasized. Advanced thermal barrier coatings have been developed using a multi-component defect clustering approach, and shown to have improved thermal stability and lower conductivity. The coating systems have been demonstrated for high temperature combustor applications. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the toughened thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion, impact and high heat-flux damage mechanisms of the thermal barrier coatings will also be described.

  17. Thermal Performance of Insulating Cryogenic Pin Spacers

    Microsoft Academic Search

    C Darve; Giovanna Vandoni

    1998-01-01

    Following the proposal to introduce an actively cooled radiation screen (5-10 K) for the LHC machine, the design of the LHC cryostat foresees the need for spacers between the cold mass and the radiati on screen. The thermal impedance of the chosen material should be very high and the shape selected to withstrand the contact stress due to the displacements

  18. Mine roof bolt

    SciTech Connect

    Gillespie, H.D.

    1993-07-27

    A mine roof bolt is described comprising: (a) a length of multi-strand cable defining a bolt shank; (b) a tapered plug comprising a body portion having an internal bore and a frusto-conical outer surface essentially concentric with said internal bore, said tapered plug being mounted about an end of said cable at said internal bore; and (c) an internally tapered drive collar having a frusto-conical inner surface that engages said frusto-conical outer surface of said tapered plug, and having an outer surface defining a drive head that accepts a driving mechanism for rotating and linearly translating said bolt, wherein said tapered plug is mounted on an end of said cable, and said drive collar is pressed down upon said tapered plug, forcing said tapered plug against said cable, such that said drive collar, said tapered plug, and said cable, when fitted tightly together, define said mine roof bolt.

  19. 30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...machines with integral roof bolters. When roof bolts are installed by a continuous mining machine...equipment: (a) The distance between roof bolts shall not exceed 10 feet crosswise. (b) Roof bolts to be installed 9 feet or more apart...

  20. 30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...machines with integral roof bolters. When roof bolts are installed by a continuous mining machine...equipment: (a) The distance between roof bolts shall not exceed 10 feet crosswise. (b) Roof bolts to be installed 9 feet or more apart...

  1. 30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...machines with integral roof bolters. When roof bolts are installed by a continuous mining machine...equipment: (a) The distance between roof bolts shall not exceed 10 feet crosswise. (b) Roof bolts to be installed 9 feet or more apart...

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

    NASA Technical Reports Server (NTRS)

    McMillan, Vernotto C.

    1998-01-01

    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.

  3. Predicted thermal performance of triple vacuum glazing

    SciTech Connect

    Fang, Yueping; Hyde, Trevor J.; Hewitt, Neil [School of the Built Environment, University of Ulster, N. Ireland (United Kingdom)

    2010-12-15

    The simulated triple vacuum glazing (TVG) consists of three 4 mm thick glass panes with two vacuum gaps, with each internal glass surface coated with a low-emittance coating with an emittance of 0.03. The two vacuum gaps are sealed by an indium based sealant and separated by a stainless steel pillar array with a height of 0.12 mm and a pillar diameter of 0.3 mm spaced at 25 mm. The thermal transmission at the centre-of-glazing area of the TVG was predicted to be 0.26 W m{sup -2} K{sup -1}. The simulation results show that although the thermal conductivity of solder glass (1 W m{sup -1} K{sup -1}) and indium (83.7 W m{sup -1} K{sup -1}) are very different, the difference in thermal transmission of TVGs resulting from the use of an indium and a solder glass edge seal was 0.01 W m{sup -2} K{sup -1}. This is because the edge seal is so thin (0.12 mm), consequently there is a negligible temperature drop across it irrespective of the material that the seal is made from relative to the total temperature difference across the glazing. The results also show that there is a relatively large increase in the overall thermal conductance of glazings without a frame when the width of the indium edge seal is increased. Increasing the rebate depth in a solid wood frame decreased the heat transmission of the TVG. The overall heat transmission of the simulated 0.5 m by 0.5 m TVG was 32.6% greater than that of the 1 m by 1 m TVG, since heat conduction through the edge seal of the small glazing has a larger contribution to the total glazing heat transfer than that of the larger glazing system. (author)

  4. Window performance for human thermal comfort

    SciTech Connect

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

    2000-07-01

    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.

  5. The effect of thermal barrier coatings on diesel engine performance

    Microsoft Academic Search

    T. Hejwowski; A. Wero?ski

    2002-01-01

    An experimental study of the effects of thin thermal barrier coatings on the performance of a diesel engine was conducted. Results obtained from the engine with thermally insulated pistons were compared with the baseline engine data. Engine trials demonstrated good properties of both coating systems. Temperature and stress distributions within the pistons were evaluated analytically by means of the Cosmos\\/Works

  6. 40 CFR 65.43 - Fixed roof with an internal floating roof (IFR).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...

  7. 40 CFR 65.43 - Fixed roof with an internal floating roof (IFR).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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...

  8. 40 CFR 65.43 - Fixed roof with an internal floating roof (IFR).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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...

  9. 40 CFR 65.43 - Fixed roof with an internal floating roof (IFR).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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...

  10. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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.

  11. Performance evaluation and simulation of a solar thermal power plant

    Microsoft Academic Search

    Eduardo I. Ortiz-Rivera; Luisa I. Feliciano-Cruz

    2009-01-01

    This paper presents a Simulinkreg Model that has been developed for the performance evaluation and simulation of Solar Power Generating or Solar Thermal Power Plants in Puerto Rico with the Compound Parabolic Concentrator as the solar collector of choice. There are several costly and sophisticated commercial software programs that perform this task but, this tool is aimed at performing initial

  12. Mine roof geology information system

    SciTech Connect

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

    2005-05-01

    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.

  13. Energy saving potential of various roof technologies

    E-print Network

    Ray, Stephen D. (Stephen Douglas)

    2010-01-01

    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, ...

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

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Bureau of Publications.

    This book is one of a series of 10 units of instruction for roofing apprenticeship classes in California. It covers the following 14 topics and provides tests for them: the nature of the roofing and waterproofing industry; the apprenticeship program; apprenticeship and the public schools; collective bargaining, wages, and benefits; safety in the…

  15. Thermal Components Boost Performance of HVAC Systems

    NASA Technical Reports Server (NTRS)

    2012-01-01

    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.

  16. Expertmental study of a Roof Solar Collector towards the natural ventilation of new habitations

    Microsoft Academic Search

    J. Khedari; J. Hirunlabh; T. Bunnag

    1996-01-01

    The paper discusses the possibility of offering thermal comfort, without inducing mechanical energy cost, in new habitations, built in European style and situated in a hot and humid climate, by means of a construction element: the Roof Solar Collector (RSC), which is made by using concrete roofing tiles on the outer side and gypsum board on the inner one. With

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

    ERIC Educational Resources Information Center

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

    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…

  18. Photovoltaic Roof Heat Flux

    NASA Astrophysics Data System (ADS)

    Samady, Mezhgan Frishta

    Solar panels were mounted with different designs onto 1:800 scale building models while temperature and radiation were measured. While there have been other studies aimed at finding the optimal angles for solar panels [9], in this study both the angle and the mounting method were tested. The three PV mounting designs that were considered to provide the most insulation to a building's rooftop were flush, offset (control), and angled. The solar panel offset height became a key component for rooftop insulation as well as the performance of the actual solar panel. Experimental results were given to verify the thermal behavior of the heat loads from the different designs of the photovoltaic panel. From the results, the angled PV design needed 16Z more heat extraction than the offset and flush PV design needed 60% more heat extracted than the offset. In addition to the heat transfer analysis, thermal models were performed to incorporate main atmospheric conditions which were based on the effects of PV mounting structure.

  19. Passive solar roof ice melter

    Microsoft Academic Search

    Deutz

    1981-01-01

    An elongated passive solar roof ice melter is placed on top of accumulated ice and snow including an ice dam along the lower edge of a roof of a heated building and is held against longitudinal movement with respect to itself. The melter includes a bottom wall having an upper surface highly absorbent to radiant solar energy; a first window

  20. Load test of the 3701U Building roof deck and support structure

    SciTech Connect

    McCoy, R.M.

    1994-09-14

    The 3701U Building roof area was load tested according to the approved load-test procedure. The 3701U Building is located in the 300 Area of the Hanford Site and has the following characteristics: Roof deck--metal decking supported by steel purlins; Roof membrane--tar and gravel; Roof slope--flat (<10 deg); and Roof elevation--height of about 12.5 ft. The 3701U Building was visited in August 1992 for a visual inspection, but because of insulation an inspection could not be performed. The building was revisited in March 1994 for the purpose of writing this test report. Because the roof could not be inspected, a test was determined to be the best way to qualify the roof for personnel access. The test procedure called for the use of a remotely-controlled robot. The conclusions are that the roof has been qualified for 500-lb total roof load and that the ``No Roof Access`` signs can be changed to ``Roof Access Restricted`` signs.

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

    SciTech Connect

    Syd S. Peng

    2002-07-15

    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.

  2. Roof control system

    SciTech Connect

    Stankus, J.C.

    1993-08-03

    Roof control system for underground strata is described, comprising: (a) an elongated bolt adapted for insertion into a hole bored in underground strata; (b) anchor means for securely anchoring the bolt in the hole at a location where a significant length of the bolt remains between the opening of the borehole and the anchor means; (c) tension means for placing said significant length of said bolt in tension by rotating the bolt at a predetermined torque, the torque means including a plate mounted on the bolt and located adjacent to the outer surface of the strata, and a nut means on the end of the bolt for engaging the plate; (d) tension/torque adjustment means for selectively adjusting friction between adjacent surfaces which rub against each other when the bolt is rotated, whereby the tension/torque ratio of the bolt is selected to match the desired level for a particular type of underground strata, the tension/torque adjustment means including an array of friction reducing washers with different contact surface areas, for location between the nut means and plate. A method of mine control for underground strata is also described using this roof bolt.

  3. Can green roof act as a sink for contaminants? A methodological study to evaluate runoff quality from green roofs.

    PubMed

    Vijayaraghavan, K; Joshi, Umid Man

    2014-11-01

    The present study examines whether green roofs act as a sink or source of contaminants based on various physico-chemical parameters (pH, conductivity and total dissolved solids) and metals (Na, K, Ca, Mg, Al, Fe, Cr, Cu, Ni, Zn, Cd and Pb). The performance of green roof substrate prepared using perlite, vermiculite, sand, crushed brick, and coco-peat, was compared with local garden soil based on improvement of runoff quality. Portulaca grandiflora was used as green roof vegetation. Four different green roof configurations, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). In general, the vegetated green roof assemblies generated better-quality runoff with less conductivity and total metal ion concentration compared to un-vegetated assemblies. Of the different green roof configurations examined, P. grandiflora planted on green roof substrate acted as sink for various metals and showed the potential to generate better runoff. PMID:25106048

  4. Solar heating shingle roof structure

    SciTech Connect

    Straza, G.T.

    1981-01-13

    A solar heating roof shingle roof structure which combines the functions of a roof and a fluid conducting solar heating panel. Each shingle is a hollow body of the general size and configuration of a conventional shingle, and is provided with a fluid inlet socket at the upper end and a fluid outlet plug at the lower end with a skirt at the lower end overlapping the plug. Shingles are assembled in an overlapping array to cover a roof structure, with interconnections between the inlets and outlets of successive longitudinally positioned shingles to provide fluid paths through the complete array. An inlet manifold is positioned at the upper end of the array or in the alternative contained in a cap used at the peak of the roof and an outlet manifold is connected to the outlet of the lowest row of shingles.

  5. Measuring mine roof bolt strains

    DOEpatents

    Steblay, Bernard J. (Lakewood, CO)

    1986-01-01

    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.

  6. Thermal Performance of EV and HEV Battery Modules and Packs

    Microsoft Academic Search

    Ahmad A. Pesaran; Andreas Vlahinos; Steven D. Burch

    Thermal issues associated with electric vehicle (EV) and hybrid electric vehicle (HEV) battery packs can significantly affect performance and life cycle. Temperature variations from module to module in a battery pack could result in reduced performance. As part of the U.S. Department of Energy's Hybrid Propulsion Systems Program, the National Renewable Energy Laboratory (NREL) works with automobile and battery manufacturers

  7. Residential solar heat pump systems - Thermal and economic performance

    Microsoft Academic Search

    J. H. Morehouse; P. J. Hughes

    1979-01-01

    This study performed an analysis of series and parallel configured solar heat pump systems for residences. The year-round thermal performance for all the heating, cooling and hot water system configurations were determined by simulation and compared against conventional heating and cooling systems in three geographic locations. The series and parallel combined solar heat pump systems investigated are at best marginally

  8. LCD display screen performance testing for handheld thermal imaging cameras

    Microsoft Academic Search

    Joshua B. Dinaburg; Francine Amon; Anthony Hamins; Paul Boynton

    2006-01-01

    Handheld thermal imaging cameras are an important tool for the first responder community. As their use becomes more prevalent, it will become important for a set of standard test metrics to be available to characterize the performance of these cameras. A major factor in the performance of the imagers is the quality of the image on a display screen. An

  9. Hydrological Modelling and Parameter Identification for Green Roof

    NASA Astrophysics Data System (ADS)

    Lo, W.; Tung, C.

    2012-12-01

    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.

  10. Thermal performance of steel-framed walls. Final report

    SciTech Connect

    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

    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.

  11. Italsat thermal control: The in-orbit performances

    Microsoft Academic Search

    Marco Giommi; Stefano Liverani; Enrico Sacchi

    1991-01-01

    Italsat F1 is a three axes stabilized communication satellite. The Italsat system consists of a global beam and a multibeam package (20\\/30 GHz) for domestic communication services and an experimental propagation package at 40\\/50 GHz with European coverage. The spacecraft thermal control design was experimentally qualified by means of a solar simulation test performed on a dedicated structural and thermal

  12. High Performance Thermal Imaging Using Quantum Well Infrared Photodetector Arrays

    Microsoft Academic Search

    Harald Schneider

    2007-01-01

    Quantum well infrared photodetector (QWIP) technology has opened up new opportunities to realize focal plane arrays (FPA) for high-performance thermal imaging [1]. High thermal and spatial resolution, low 1\\/f noise, low fixed-pattern noise, and high pixel operability makes QWIP FPAs appropriate for many applications. Due to their narrow absorption bands with relative spectral widths deltalambda\\/lambda of the order of 10%,

  13. The technical viability of alternative blowing agents in polyisocyanurate roof insulation

    SciTech Connect

    Christian, J.E.; Courville, G.E.; Linkous, R.L.; Wendt, R.L.; Graves, R.S. (Oak Ridge National Lab., TN (USA)); Smith, T.L. (National Roofing Contractors Association, Chicago, IL (USA))

    1990-01-01

    This paper presents a progress report on field thermal performance measurements on a set of private industry-produced, experimental polyisocyanurate laminate board stock foams blown with CFC-11, HCFC-123, HCFC-141b, 50/50, and 65/35 blends of HCFC-123/HCFC-141b. These boards have been observed for almost 300 days of roof field exposure in East Tennessee. The field data are used to derive an empirical model which can be used to predict effective diffusion coefficients for the air components into the foam cells. These diffusion coefficients are compared with those developed from steady state laboratory measurements of thin sliced samples from the same batch of experimental boards. The relative performance of test specimens of HCFC-141b under a black and under a white membrane are reported. The aging of the HCFC-141b blown foam under the white membrane occurred more slowly during cold weather, but accelerated after the winter season, resulting in no significant resistivity difference after 280 days of exposure from September 1989 until May 1990. The field data analysis suggests that the percent increase in k over that of the foam blown with CFC-11 is, after one year of aging, 5.5% for HCFC-123 and 11.7% for HCFC-141b. This leads to the same ordering as derived from the laboratory thin-slicing analysis report in Part 3 of this session. Additional plans are described for further thermal and mechanical property measurements to be conducted on two ORNL roof field testers. After the first year of this three-year study, there has been no indication that thermal performance differences are serious enough to suggest that any or all of the HCFC alternate blowing agents would not be technically viable in polyisocyanurate roof insulations. 5 refs., 19 figs.

  14. Measured energy savings of light colored roofs: Results from three California demonstration sites

    SciTech Connect

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

    1998-06-01

    Measured data and computer simulations have demonstrated the impact of roof albedo in reducing cooling energy use in buildings. Savings are a function of both climate and the amount of roof insulation. The cooling energy savings for reflective roofs are highest in hot climates. A reflective roof may also lead to higher heating energy use. Reflective coatings are also used in commercial buildings to protect the roofing membrane, and hence, maintain and prolong the useful life of the roof. Reflectivity of coatings changes with weathering and aging which in turn could have an effect on building cooling-energy savings. For that reason, reflective roof coatings are not primarily marketed for their energy savings potential. To monitor the field performance of reflective coatings, the authors initiated a demonstration project where three commercial buildings in California were painted with light-colored roof coatings. The buildings are two medical care centers and one drug store. At all sites, the roof reflectance, both fresh and aged, and cooling energy use were monitored. In addition, they measured temperature throughout the roof systems and inside the conditioned space. In the monitored buildings, increasing the roof reflectance from an initial value of about 20% to 60%, dropped the roof temperature on hot summer afternoons by about 45 F. Summertime standard-weekday average daily air-conditioning savings were 18% (198 kWh) in the first medical office building, 13% (86 kWh) in the second medical office building, and 2% (13 kWh) in the drug store. The overall u-value of the roofs had dictated the impact of roof reflectance.

  15. Thermal Performance Testing of EMU and OSS Liquid Cooling Garments

    NASA Technical Reports Server (NTRS)

    Rhodes, Richard; Bue, Grant; Hakam, Mary

    2012-01-01

    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.

  16. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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.

  17. Potential benefits of cool roofs on commercial buildings: conserving energy, saving money, and reducing emission of greenhouse gases and air pollutants

    Microsoft Academic Search

    Ronnen Levinson; Hashem Akbari

    2010-01-01

    Cool roofs—roofs that stay cool in the sun by minimizing solar absorption and maximizing thermal emission—lessen the flow\\u000a of heat from the roof into the building, reducing the need for space cooling energy in conditioned buildings. Cool roofs may\\u000a also increase the need for heating energy in cold climates. For a commercial building, the decrease in annual cooling load\\u000a is

  18. VO? nanorods for efficient performance in thermal fluids and sensors.

    PubMed

    Dey, Kajal Kumar; Bhatnagar, Divyanshu; Srivastava, Avanish Kumar; Wan, Meher; Singh, Satyendra; Yadav, Raja Ram; Yadav, Bal Chandra; Deepa, Melepurath

    2015-04-14

    VO2 (B) nanorods with average width ranging between 50-100 nm are synthesized via a hydrothermal method and the post hydrothermal treatment drying temperature is found to be influential in their overall phase and growth morphology evolution. The nanorods with unusually high optical bandgap for a VO2 material are effective in enhancing the thermal performance of ethylene glycol nanofluids over a wide temperature range as is indicated by the temperature dependent thermal conductivity measurements. Humidity and LPG sensors fabricated using the VO2 (B) nanorods bear testament to their efficient sensing performance, which can be partially attributed to the mesoporous nature of the nanorods. PMID:25773921

  19. Duct thermal performance models for large commercial buildings

    SciTech Connect

    Wray, Craig P.

    2003-10-01

    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.

  20. Solar heater and roof attachment means

    Microsoft Academic Search

    G. L. Howe; S. G. Koutavas

    1984-01-01

    A solar heater includes an elongated solar collector having two fixedly connected solar panels of highly heat conductive material supported by a roof clamp on a shingled roof. The bottom edges of each of the solar panels include upturned gutter portions. One form of roof clamp for shingled roofs includes a J-shape shingle clamp member having a clamp bolt extending

  1. The geometric theory of roof reflector resonators

    Microsoft Academic Search

    H. E. Evans II

    1976-01-01

    Laser resonators using roof reflectors with 90 deg - alpha roof angles ( alpha small and positive) are analyzed geometrically when the roof edges at opposite ends of the resonator are aligned either parallel or perpendicular (crossed). Stability conditions, involving reflector dimensions, are found which specify a maximum axis length for the existence of stable rays. In the parallel-roof case,

  2. Solar Roof Cooling by Evaporation 

    E-print Network

    Patterson, G. V.

    1982-01-01

    : BLISTERS: o Bliste6s form when the roof temperatures reach 150 to 165. The gravel falls off the blister a~d this allows the ultra violet rays of the sun to dlrectly attack the asphalt. This causes the oils to dry out, cracking occurs, and roof problems... intermit the roof, then allowing it to eva8orate, we can tently, then allowing it to evaporate, we can pro cool the soof to within 10 0 to 12 of wet bulb. duce the same effect of cooling the interior of the With a 76 wet bulb, this means that we can...

  3. Dynamic Thermal Management for High-Performance Storage Systems

    SciTech Connect

    Kim, Youngjae [ORNL; Gurumurthi, Dr Sudhanva [University of Virginia; Sivasubramaniam, Anand [Pennsylvania State University

    2012-01-01

    Thermal-aware design of disk drives is important because high temperatures can cause reliability problems. Dynamic Thermal Management (DTM) techniques have been proposed to operate the disk at the average case temperature, rather than at the worse case by modulating the activities to avoid thermal emergencies. The thermal emergencies can be caused by unexpected events, such as fan-breaks, increased inlet air temperature, etc. One of the DTM techniques is a delay-based approach that adjusts the disk seek activities, cooling down the disk drives. Even if such a DTM approach could overcome thermal emergencies without stopping disk activity, it suffers from long delays when servicing the requests. Thus, in this chapter, we investigate the possibility of using a multispeed disk-drive (called dynamic rotations per minute (DRPM)) that dynamically modulates the rotational speed of the platter for implementing the DTM technique. Using a detailed performance and thermal simulator of a storage system, we evaluate two possible DTM policies (- time-based and watermark-based) with a DRPM disk-drive and observe that dynamic RPM modulation is effective in avoiding thermal emergencies. However, we find that the time taken to transition between different rotational speeds of the disk is critical for the effectiveness of the DRPM based DTM techniques.

  4. Thermal performance modeling of NASA s scientific balloons

    NASA Astrophysics Data System (ADS)

    Franco, H.; Cathey, H.

    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.

  5. Portable Life Support Subsystem Thermal Hydraulic Performance Analysis

    NASA Technical Reports Server (NTRS)

    Barnes, Bruce; Pinckney, John; Conger, Bruce

    2010-01-01

    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.

  6. Measured performance of a solar augmented heat pump/chiller system with thermal storage in tanks of stratified water

    SciTech Connect

    Wildin, M.W.

    1983-01-01

    The performance of the heating and cooling system in a building designed to illustrate energy conservation, solar energy use and thermal storage for electric load management and energy conservation was monitored for a period of 20 months, beginning in January 1981. Solar energy was employed to augment the heating energy obtained by heat recovery using electric-driven reciprocating heat pump/chillers and an air-to-air heat exchanger. Solar energy was gathered by 289 m/sup 2/ (3110 ft/sup 2/) of evacuated tube collectors on the roof of the building, which has a gross floor area of 5330 m/sup 2/ (57,350 ft/sup 2/). The fractions of the total active heating load, including air-to-air heat recovery, supplied by solar energy for the one partial and one completed heating season for which results were obtained, were 50 and 42 percent, respectively. Stratified water tanks were used in the heating season to store excess solar energy and both heating and cooling capacity generated by the heat pump/chillers. During the cooling season, the tanks were used to store cooling capacity generated by the chillers. An economic analysis using the results for energy consumption obtained from this building indicated that the solar system was not economically attractive, despite its encouraging technical performance. Thermal storage for electric load management was attractive for moderate costs of capital.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  8. Joint Industry\\/Government Research Project: Comparison of thermal aging for roof exposures and thin-specimens of experimental polyisocyanurate insulation foamed with alternative blowing agents

    Microsoft Academic Search

    R. S. Graves; J. E. Christian; D. L. McElroy

    1991-01-01

    This paper reports apparent thermal conductivity (k) values from field exposures and laboratory aging of a set of industry-produced, experimental polyisocyanurate (PIR) laminated boardstock foamed with hydrochlorofluorocarbons (HCFCs) as alternative to chlorofluorocarbons (CFCs). The k-values were determined from 0 to 50°C using techniques that meet ASTM C 1114 (Thin Heater Apparatus) and ASTM C 518 (Heat Flow Meter Apparatus). The

  9. AEETES: A solar reflux receiver thermal performance numerical model

    NASA Astrophysics Data System (ADS)

    Hogan, R. E., Jr.

    1991-12-01

    Reflux solar receivers for dish-Stirling electric power generation systems are currently being investigated by several companies and laboratories. In support of these efforts, the AEETES thermal performance numerical model has been developed to predict thermal performance of pool-boiler and heat-pipe reflux receivers. The formulation of the AEETES numerical model, which is applicable to axisymmetric geometries with asymmetric incident fluxes, is presented in detail. Thermal efficiency predictions agree to within 4.1 percent with test data from on-sun tests of a pool-boiler reflux receiver. Predicted absorber and sidewall temperatures agree with thermocouple data to within 3.3. percent and 7.3 percent, respectively. The importance of accounting for the asymmetric incident fluxes is demonstrated in comparisons with predictions using azimuthally averaged variables. The predicted receiver heat losses are characterized in terms of convective, solar and infrared radiative, and conductive heat transfer mechanisms.

  10. Integrated heat pipe-thermal storage system performance evaluation

    NASA Astrophysics Data System (ADS)

    Keddy, E.; Sena, J. T.; Merrigan, M.; Heidenreich, Gary

    An integrated thermal energy storage (TES) system, developed as a part of an organic Rankine cycle solar dynamic power system is described, and the results of the performance verification tests of this TES system are presented. The integrated system consists of potassium heat-pipe elements that incorporate TES canisters within the vapor space, along with an organic fluid heater tube used as the condenser region of the heat pipe. The heat pipe assembly was operated through the range of design conditions from the nominal design input of 4.8 kW to a maximum of 5.7 kW. The performance verification tests show that the system meets the functional requirements of absorbing the solar energy reflected by the concentrator, transporting the energy to the organic Rankine heater, providing thermal storage for the eclipse phase, and allowing uniform discharge from the thermal storage to the heater.

  11. Integrated heat pipe-thermal storage system performance evaluation

    NASA Technical Reports Server (NTRS)

    Keddy, E.; Sena, J. T.; Merrigan, M.; Heidenreich, Gary

    1987-01-01

    An integrated thermal energy storage (TES) system, developed as a part of an organic Rankine cycle solar dynamic power system is described, and the results of the performance verification tests of this TES system are presented. The integrated system consists of potassium heat-pipe elements that incorporate TES canisters within the vapor space, along with an organic fluid heater tube used as the condenser region of the heat pipe. The heat pipe assembly was operated through the range of design conditions from the nominal design input of 4.8 kW to a maximum of 5.7 kW. The performance verification tests show that the system meets the functional requirements of absorbing the solar energy reflected by the concentrator, transporting the energy to the organic Rankine heater, providing thermal storage for the eclipse phase, and allowing uniform discharge from the thermal storage to the heater.

  12. Thermal modeling and performance analysis of a thermoacoustic refrigerator.

    PubMed

    Holmberg, David G; Chen, G S; Lin, H T; Wo, Andrew M

    2003-08-01

    A heat-driven thermoacoustic refrigerator has been designed and tested. A detailed thermal model of the device is presented. Energy balances within the system are discussed using external, heat exchanger, and stack control volumes in order to clarify the relationships of work and heat fluxes below and above onset. Thermal modeling is discussed as a tool for performance analysis as well as for determining system heat losses and finding input heat flows required by a thermoacoustic code. A method of using the control volume balance equations to find stack work and device efficiencies is presented. Experimental measurements are compared to DELTAE thermoacoustic modeling predictions. Modeling results show that viscous losses within the system have a significant impact on the device performance as well as on the ability of DELTAE to accurately predict performance. Modeling has led to an understanding of system performance and highlighted loss sources that are areas for improvement in a redesign. PMID:12942961

  13. Comparative performance of solar thermal power generation concepts

    NASA Technical Reports Server (NTRS)

    Wen, L.; Wu, Y. C.

    1976-01-01

    A performance comparison is made between the central receiver system (power tower) and a distributed system using either dishes or troughs and lines to transport fluids to the power station. These systems were analyzed at a rated capacity of 30 MW of thermal energy delivered in the form of superheated steam at 538 C (1000 F) and 68 atm (1000 psia), using consistent weather data, collector surface waviness, pointing error, and electric conversion efficiency. The comparisons include technical considerations for component requirements, land utilization, and annual thermal energy collection rates. The relative merits of different representative systems are dependent upon the overall conversion as expressed in the form of performance factors in this paper. These factors are essentially indices of the relative performance effectiveness for different concepts based upon unit collector area. These performance factors enable further economic tradeoff studies of systems to be made by comparing them with projected production costs for these systems.

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

    Microsoft Academic Search

    S. Cristina; A. Orlandi

    1991-01-01

    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

  15. Miniaturized high-performance starring thermal imaging system

    Microsoft Academic Search

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

    2000-01-01

    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

  16. Thermal performance of a vegetated cladding system on facade walls

    Microsoft Academic Search

    C. Y. Cheng; Ken K. S. Cheung; L. M. Chu

    2010-01-01

    An experimental approach is used to assess the effect of vegetation on the thermal performance of a vertical greening system, which comprised of turf-based vertical planting modules, on an elevated facade wall of a public housing apartment. Despite temperature fluctuations in the various compartments external and internal to a concrete wall, the vegetated cladding reduced interior temperatures and delayed the

  17. Integrated heat pipe-thermal storage system performance evaluation

    Microsoft Academic Search

    E. Keddy; J. T. Sena; M. Merrigan; Gary Heidenreich

    1987-01-01

    An integrated thermal energy storage (TES) system, developed as a part of an organic Rankine cycle solar dynamic power system is described, and the results of the performance verification tests of this TES system are presented. The integrated system consists of potassium heat-pipe elements that incorporate TES canisters within the vapor space, along with an organic fluid heater tube used

  18. Thermoacoustic power effect on the refrigeration performance of thermal separators

    Microsoft Academic Search

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

    2003-01-01

    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

  19. Thermal performances investigation of a wet cooling tower

    Microsoft Academic Search

    M. Lemouari; M. Boumaza; I. M. Mujtaba

    2007-01-01

    This paper presents an experimental investigation of the thermal performances of a forced draft counter flow wet cooling tower filled with an “VGA” (Vertical Grid Apparatus) type packing. The packing is 0.42m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross sectional test

  20. THERMAL PERFORMANCE OF THE LDX FLOATING COIL A. Zhukovsky1

    E-print Network

    THERMAL PERFORMANCE OF THE LDX FLOATING COIL A. Zhukovsky1 , D.T. Garnier2 , A.L. Radovinsky1 1 MIT levitated in the center of a 5 m diameter by 3 m tall vacuum chamber. The floating coil (F-coil) consists in the middle of the vacuum chamber without electric and cryogenic connections to the coil. For this reason

  1. Single Port ElectroThermal Propulsion-Performance Factors

    Microsoft Academic Search

    Donald G. Johansen

    2008-01-01

    Performance models for single port ETP (Electro-Thermal Propulsion) devices are presented considering all significant efficiency factors. Single-port ETP devices, which use the nozzle exit as entrance port for beamed power, are capable of high efficiency and high thrust with low mass penalty for both propellant and structure. Previously considered parabolic nozzle shapes have operated in pulse mode to exchange energy

  2. Single Port ElectroThermal Propulsion—Performance Factors

    Microsoft Academic Search

    Donald G. Johansen

    2008-01-01

    Performance models for single port ETP (Electro-Thermal Propulsion) devices are presented considering all significant efficiency factors. Single-port ETP devices, which use the nozzle exit as entrance port for beamed power, are capable of high efficiency and high thrust with low mass penalty for both propellant and structure. Previously considered parabolic nozzle shapes have operated in pulse mode to exchange energy

  3. Performance evaluation of solar photovoltaic\\/thermal systems

    Microsoft Academic Search

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

    2001-01-01

    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

  4. Comparative performance of solar thermal power generation concepts

    Microsoft Academic Search

    L. Wen; Y. C. Wu

    1976-01-01

    A performance comparison is made between the central receiver system (power tower) and a distributed system using either dishes or troughs and lines to transport fluids to the power station. These systems were analyzed at a rated capacity of 30 MW of thermal energy delivered in the form of superheated steam at 538 C (1000 F) and 68 atm (1000

  5. Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions

    Microsoft Academic Search

    Jeremy Lundholm; J. Scott Macivor; Zachary MacDougall; Melissa Ranalli; Hans Henrik Bruun

    2010-01-01

    BackgroundGreen 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

  6. Statistical Building Roof Reconstruction from WORLDVIEW-2 Stereo Imagery

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

  7. Architectural designs and thermal performances of school sports-halls

    Microsoft Academic Search

    Abd El-Wahab M. Adel El-Kadi; Mona A. Fanny

    2003-01-01

    The school playground is an essential part of any school building because of its important role in the overall teaching process. The study presents the current design of most of the governmental school playgrounds in Cairo and shows how existing playgrounds sustain this function and describes the inherent shortcomings of that design. Constructing a sports hall on the roof of

  8. Thermal Performance of Uninsulated and Partially Filled Wall Cavities

    Microsoft Academic Search

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

    2011-01-01

    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.

  9. Versatile roof bolt assembly

    SciTech Connect

    Hipkins, E.C. Sr.; Locotos, F.M.

    1987-11-03

    In an anchor bolt assembly of the type used in mine roofs and the like in which the anchor bolt assembly is positioned in a bore hole of a rock formation, where the bolt assembly includes an elongated bolt shaft with an upper end and with a head on a lower end, wherein a quick-setting resin cartridge is positioned in the bore hole above the upper end of the bolt shaft, and wherein the anchor bolt assembly is secured to the rock formation by at least the quick-setting resin, the improvement is described comprising an entrant plug provided at the upper end of the bolt shaft and adapted to rupture the resin cartridge and an elongated helical coil external of and surrounding the bolt shaft. It has a direction of coil for mixing the quick-setting resin and urging the quick-setting resin upwardly toward the upper end while the bolt shaft is rotated in one continuous direction. The helical coil is disposed below the entrant plug and connected to the entrant plug or the bolt shaft and extending a substantial length along the bolt shaft to achieve the mixing.

  10. Development of a green roof environmental monitoring and meteorological network in new york city.

    PubMed

    Gaffin, Stuart R; Khanbilvardi, Reza; Rosenzweig, Cynthia

    2009-01-01

    Green roofs (with plant cover) are gaining attention in the United States as a versatile new environmental mitigation technology. Interest in data on the environmental performance of these systems is growing, particularly with respect to urban heat island mitigation and stormwater runoff control. We are deploying research stations on a diverse array of green roofs within the New York City area, affording a new opportunity to monitor urban environmental conditions at small scales. We show some green roof systems being monitored, describe the sensor selection employed to study energy balance, and show samples of selected data. These roofs should be superior to other urban rooftops as sites for meteorological stations. PMID:22574037

  11. Thermal performance modification of composite materials. [for missiles

    NASA Technical Reports Server (NTRS)

    Ramohalli, K.; Mink, M.

    1979-01-01

    This paper reports on an investigation of the concept of modifying the thermal performance of filled polymers through a minor compositional change (presently by coating the filler). The fire-safety of construction materials and the instability of solid rockets are used as examples. A theory is developed which shows that vast improvements are possible by controlling thermal conductivity. Experiments are described that show the weight loss and smoke density in the NBS smoke-density chamber of fiberglass-reinforced epoxy panels, and the instability trends of an AP-HTPB propellant fired in an L-Star rocket motor. The feasibility of tailoring thermal behavior to suit each particular need is demonstrated.

  12. Thermal management and overall performance of a high concentration PV

    NASA Astrophysics Data System (ADS)

    Escher, Werner; Paredes, Stephan; Zimmermann, Severin; Ong, Chin Lee; Ruch, Patrick; Michel, Bruno

    2012-10-01

    An advanced thermal management approach for HCPV systems is demonstrated in this manuscript, proposing the concept of efficient heat recovery at ultra high concentration ratios by collecting the heat on a high temperature level. With the availability of this low grade heat, the efficiency of the HCPV system is increased further as the 'waste' heat is supplied to different thermal consumers engaging in thermal desalination or adsorption cooling processes. To asses the value of the concept, we have estimated the economic value of heat with regard to its consumer and observed that this differs from its thermodynamic value. This valuable input is was used to determine the overall generated value of a dual output system as a function of the operation temperature, where we have actively demonstrated a superior performance of the HCPVT.

  13. 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

    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

    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).

  14. Thermal performance of phase change wallboard for residential cooling application

    SciTech Connect

    Feustel, H.E.; Stetiu, C.

    1997-04-01

    Cooling of residential California buildings contributes significantly to electrical consumption and peak power demand mainly due to very poor load factors in milder climates. Thermal mass can be utilized to reduce the peak-power demand, downsize the cooling systems, and/or switch to low-energy cooling sources. Large thermal storage devices have been used in the past to overcome the shortcomings of alternative cooling sources, or to avoid high demand charges. The manufacturing of phase change material (PCM) implemented in gypsum board, plaster or other wall-covering material, would permit the thermal storage to become part of the building structure. PCMs have two important advantages as storage media: they can offer an order-of-magnitude increase in thermal storage capacity, and their discharge is almost isothermal. This allows the storage of high amounts of energy without significantly changing the temperature of the room envelope. As heat storage takes place inside the building, where the loads occur, rather than externally, additional transport energy is not required. RADCOOL, a thermal building simulation program based on the finite difference approach, was used to numerically evaluate the latent storage performance of treated wallboard. Extended storage capacity obtained by using double PCM-wallboard is able to keep the room temperatures close to the upper comfort limits without using mechanical cooling. Simulation results for a living room with high internal loads and weather data for Sunnyvale, California, show significant reduction of room air temperature when heat can be stored in PCM-treated wallboards.

  15. Thermal performance of a customized multilayer insulation (MLI)

    NASA Technical Reports Server (NTRS)

    Leonhard, K. E.

    1976-01-01

    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.

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

    E-print Network

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

    2013-01-01

    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...

  17. Single Port Electro-Thermal Propulsion—Performance Factors

    NASA Astrophysics Data System (ADS)

    Johansen, Donald G.

    2008-04-01

    Performance models for single port ETP (Electro-Thermal Propulsion) devices are presented considering all significant efficiency factors. Single-port ETP devices, which use the nozzle exit as entrance port for beamed power, are capable of high efficiency and high thrust with low mass penalty for both propellant and structure. Previously considered parabolic nozzle shapes have operated in pulse mode to exchange energy at a concentrated focal region, resulting in low efficiency. The proposed cone/bell shape diffuses the focal region prior to chamber entry to allow continuous combustion inside the chamber with high efficiency. Mechanical and thermal limits are evaluated. For vacuum operation, low chamber pressure operation is possible. Thin wall thruster construction results in low chamber and nozzle mass. Further, at low pressure, regenerative cooling is needed only for the chamber and throat region with radiation cooling for the nozzle exit region. These factors permit high expansion ratio and thrust-to-weight ratio needed for performance.

  18. Fluid and thermal performance analysis of PMSM used for driving

    NASA Astrophysics Data System (ADS)

    Ding, Shuye; Cui, Guanghui; Li, Zhongyu; Guan, Tianyu

    2015-05-01

    The permanent magnet synchronous motor (PMSM) is widely used in ships under frequency conversion control system. The fluid flow performance and temperature distribution of the PMSM are difficult to clarify due to its complex structure and variable frequency control condition. Therefore, in order to investigate the fluid and thermal characteristics of the PMSM, a 50 kW PMSM was taken as an example in this study, and a 3-D coupling analysis model of fluid and thermal was established. The fluid and temperature fields were calculated by using finite volume method. The cooling medium's properties, such a velocity, streamlines, and temperature, were then analyzed. The correctness of the proposed model, and the rationality of the solution method, were verified by a temperature test of the PMSM. In this study, the changing rheology on the performance of the cooling medium and the working temperature of the PMSM were revealed, which could be helpful for designing the PMSM.

  19. Scrutinizing Gypsum Board Thermal Performance at Dehydration Temperatures

    Microsoft Academic Search

    D. Kontogeorgos; I. Mandilaras; M. Founti

    2011-01-01

    This article investigates the thermal performance of gypsum boards in the dehydration temperature region, where pronounced chemical reactivity is anticipated. Gypsum board samples were gradually heated up to 300°C, using a low heating rate. Temperature measurements at pre-selected board locations indicated three distinct stages of gypsum dehydration; free moisture evaporation, transformation of calcium sulfate dihydrate to calcium sulfate hemi-hydrate and

  20. ENERGY PERFORMANCE OF BOREHOLE THERMAL ENERGY STORAGE SYSTEMS

    Microsoft Academic Search

    Hiroshi Ohga; Kenji Mikoda; Rio de Janeiro

    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

  1. Thermal performance of shape-stabilized phase change paraffin wallboard

    Microsoft Academic Search

    Yan Quanying; Li Lisha; Liang Chen

    2010-01-01

    This paper presents thermal performance of shape-stabilized phase change material (PCM) wallboards and common wallboard. Shape-stabilized PCMs consist of paraffin and high-density polyethylene as support materials. The wallboards were prepared by shape-stabilized PCMs and grout with the building materials in mass proportions of 5%, 10%, and 15%. The phase change temperature of the shape-stabilized paraffin was 27.5 °C and the maximum

  2. Heat exchanger thermal performance for two nonazeotropic refrigerant mixtures

    SciTech Connect

    Conklin, J.C.; Vineyard, E.A.

    1991-08-15

    Two nonazeotropic refrigerant mixtures (NARMs), the first consisting of 71% R22 and 29% R114 and the second consisting of 75% R143a and 25% R124 (approximate percentages by mass), were studied at various mass flow rate and heat loads in an experimental apparatus at Oak Ridge National Laboratory. The measured thermal performance of the evaporator and the condenser are presented in terms of the number of transfer units (NTU) and effectiveness ({epsilon}). Because the phase-change process of the NARMS is nonisothermal, a specific heat for the two-phase region can be defined. This two-phase specific heat for the NARMs varies with respect to enthalpy. Because the standard NTU-{epsilon} analysis is valid only for constant specific heat fluids, and analysis that considers variable specific heat fluids is used to compare analytical predictions of the thermal performance with the observed thermal performance. The predicted and measured results show very good agreement when the pressure drop is low. 6 refs., 4 figs., 4 tabs.

  3. Effects of building roof greening on air quality in street canyons

    NASA Astrophysics Data System (ADS)

    Baik, Jong-Jin; Kwak, Kyung-Hwan; Park, Seung-Bu; Ryu, Young-Hee

    2012-12-01

    Building roof greening is a successful strategy for improving urban thermal environment. It is of theoretical interest and practical importance to study the effects of building roof greening on urban air quality in a systematic and quantitative way. In this study, we examine the effects of building roof greening on air quality in street canyons using a computational fluid dynamics (CFD) model that includes the thermodynamic energy equation and the transport equation of passive, non-reactive pollutants. For simplicity, building roof greening is represented by specified cooling. Results for a simple building configuration with a street canyon aspect ratio of one show that the cool air produced due to building roof greening flows into the street canyon, giving rise to strengthened street canyon flow. The strengthened street canyon flow enhances pollutant dispersion near the road, which decreases pollutant concentration there. Thus, building roof greening improves air quality near the road. The degree of air quality improvement near the road increases as the cooling intensity increases. In the middle region of the street canyon, the air quality can worsen when the cooling intensity is not too strong. Results for a real urban morphology also show that building roof greening improves air quality near roads. The degree of air quality improvement near roads due to building roof greening depends on the ambient wind direction. These findings provide a theoretical foundation for constructing green roofs for the purpose of improving air quality near roads or at a pedestrian level as well as urban thermal environment. Further studies using a CFD model coupled with a photochemistry model and a surface energy balance model are required to evaluate the effects of building roof greening on air quality in street canyons in a more realistic framework.

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

    SciTech Connect

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

    2004-07-01

    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).

  5. 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

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

    NASA Astrophysics Data System (ADS)

    Hoover, F.; Bowling, L. C.

    2013-12-01

    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.

  7. 7 CFR 2902.11 - Roof coatings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...formulated for use in commercial roof deck systems to provide a single-coat...responsibility for drafting or reviewing specifications for items to be procured shall ensure that the relevant specifications require the use of biobased roof...

  8. IDENTIFYING ROOF FALL PREDICTORS USING FUZZY CLASSIFICATION

    SciTech Connect

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

    2010-02-22

    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.

  9. Thermoacoustic power effect on the refrigeration performance of thermal separators

    NASA Astrophysics Data System (ADS)

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

    2003-09-01

    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.

  10. Media depth influences Sedum green roof establishment

    Microsoft Academic Search

    Kristin L. Getter; D. Bradley Rowe

    2008-01-01

    Species selection and initial establishment of plants is critical for long term survival and health of green roofs. Plants\\u000a that can withstand harsh environmental conditions and provide rapid coverage on extensive green roofs can reduce erosion,\\u000a limit weed invasion, and provide a more aesthetically pleasing roof to satisfy customers. This study evaluated the effect\\u000a of green roof substrate depth on

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

    ERIC Educational Resources Information Center

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

    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…

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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.

  13. Roofing shingle assembly having solar capabilities

    SciTech Connect

    Murphy, J.A.

    1982-03-16

    A roofing shingle assembly having solar capabilities comprising a flat main portion having upper and lower surfaces, and curved segments integral with the upper and lower edges of said shingle. The roofing shingles are mounted in overlapping parallel array with the curved segments interconnected to define a fluid conduit enclosure. Mounting brackets for the shingles are secured on the roof rafters.

  14. Roofing shingle assembly having solar capabilities

    Microsoft Academic Search

    1982-01-01

    A roofing shingle assembly having solar capabilities comprising a flat main portion having upper and lower surfaces, and curved segments integral with the upper and lower edges of said shingle. The roofing shingles are mounted in overlapping parallel array with the curved segments interconnected to define a fluid conduit enclosure. Mounting brackets for the shingles are secured on the roof

  15. SOLAR ROOF POWERS THE NJIT CAMPUS CENTER

    E-print Network

    Bieber, Michael

    SOLAR ROOF POWERS THE NJIT CAMPUS CENTER THE SKY'S THE LIMIT: BERNADETTE MOKE SITS ON THE ROOF, ARE 160 SOLAR PANELS, SOME OF WHICH AUTOMATICALLY FOLLOW THE PATH OF THE SUN. 10 NJITMAGAZINE COVER STORY'S THE LIMIT: SOLAR ROOF POWERS THE NJIT CAMPUS CENTER "The solar panels even move a little at night," says

  16. A Study of The Thermal Performance of Cold-formed Thin-walled Perforated Steel Studs (Thermal Studs) in Fire

    Microsoft Academic Search

    B. Salhab; Yong Wang

    2004-01-01

    Perforating thin-walled steel studs in steel framed housing is an effective method of reducing heat loss and improving energy efficiency. Steel studs with perforation for energy efficiency are called thermal studs. This paper presents an experimental and numerical investigation of the thermal performance of lipped thermal studs in fire. Four tests were carried out in the fire-testing laboratory of the

  17. Moisture design to improve durability of low-slope roofing systems

    SciTech Connect

    Desjarlais, A. [Oak Ridge National Lab., TN (United States); Byars, N. [Univ. of North Carolina, Charlotte, NC (United States)

    1996-12-31

    The roofing industry has traditionally held that moisture control in low-slope roofing comprises two independent elements: (1) provide a waterproof exterior covering (or membrane) to protect the low-slope roof from external sources of moisture and (2) perform a condensation calculation to determine if a vapor retarder is required to protect a roof system from internal moisture sources. The first criterion is assumed to be satisfied if a membrane system is specified; in reality, all membrane systems eventually fail, and existing moisture control strategies offer no mechanism for analyzing the inevitable failure. The means of assessing the second criterion, the need for a vapor retarder, has evolved in recent years. The criteria have become more liberal with time because it has been observed that roofing systems installed in a geographic area in which the old criteria required a vapor retarder, have performed well without one.

  18. Acute traumatic orbital encephalocele related to orbital roof fracture: reconstruction by using porous polyethylene.

    PubMed

    Gazio?lu, Nurperi; Ulu, Mustafa Onur; Ozlen, Fatma; Uzan, Mustafa; Ciplak, Nejat

    2008-07-01

    A case report of acute traumatic orbital encephalocele related to orbital roof fracture and its management were presented. Acute traumatic encephalocele related to orbital roof fracture is unusual. Early diagnosis and treatment are very important since the raised intraorbital pressure may irreversibly damage the optic nerve. Orbital computerized tomography with thin axial and coronal sections should be performed in an acute traumatized patient with a concurrent orbital trauma. Reconstruction of the orbital roof is the key step of the surgical treatment and should be performed in every case. Porous polyethylene (Medpor) has been used for many years in reconstructive surgeries and it is superior to other allografts in many ways. In our case, the orbital roof reconstruction was done by Medpor and the early and late cosmetic results were excellent. The important features of acute traumatic encephalocele secondary to orbital roof fractures in terms of presentation, diagnosis and surgical steps were also stressed. PMID:18781424

  19. Roof bolt assembly having a sealing plug for preventing a deterioration of the mine roof

    SciTech Connect

    Unrug, K.F.; Thompson, E.D.; Nandy, S.K.

    1987-09-15

    This patent describes a roof bolt assembly for preserving the natural geological structure of a mine roof which consists of an elongated bolt rod with first and second distal ends, an expandable anchor threaded on the first end for operatively engaging the walls of a roof bolt hole bored in the mine roof at points inboard of the roof surface, a bolt head on the second end of the bolt rod, and a roof plate sandwiched between the roof surface and the bolt head. The entire assembly is pre-tensioned to tightly hold the roof plate against the roof surface. The hole bored in the roof is larger in diameter than the diameter of the roof bolt rod defining an annular space around the rod. The improvement comprises sealing means totally disposed within the annular space adjacent the second end of the bolt but spaced from the roof plate. The sealing means further being spaced from the roof surface such that a gap is formed between the roof surface and the sealing means. The sealing means preclude the entrance of air and moisture into the hole and the annular space around the rod is generally free from material in a region between the anchor and the sealing means such that the bolt is generally out of contact with the mine roof in this region.

  20. Passive solar roof ice melter

    SciTech Connect

    Deutz, R.T.

    1981-09-29

    An elongated passive solar roof ice melter is placed on top of accumulated ice and snow including an ice dam along the lower edge of a roof of a heated building and is held against longitudinal movement with respect to itself. The melter includes a bottom wall having an upper surface highly absorbent to radiant solar energy; a first window situated at right angles with respect to the bottom wall, and a reflecting wall connecting the opposite side edges of the bottom wall and the first window. The reflecting wall has a surface facing the bottom wall and the window which is highly reflective to radiant solar energy. Radiant solar energy passes through the first window and either strikes the highly absorbent upper surface of the bottom wall or first strikes the reflecting wall to be reflected down to the upper surface of the bottom wall. The heat generated thereby melts through the ice below the bottom wall causing the ice dam to be removed between the bottom wall and the top of the roof and immediately adjacent to the ice melter along the roof. Water dammed up by the ice dam can then flow down through this break in the dam and drain out harmlessly onto the ground. This prevents dammed water from seeping back under the shingles and into the house to damage the interior of the house.

  1. Solar Roof Cooling by Evaporation

    E-print Network

    Patterson, G. V.

    1980-01-01

    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...

  2. Thermal performance evaluation of the Semco (liquid) solar collector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Procedures used and results obtained during the evaluation test program on a flat plate collector which uses water as the working fluid are discussed. The absorber plate is copper tube soldered to copper fin coated with flat black paint. The glazing consists of two plates of Lo-Iron glass; the insulation is polyurethane foam. The collector weight is 242.5 pounds with overall external dimensions of approximately 48.8 in. x 120.8 in. x 4.1 in. The test program was conducted to obtain thermal performance data before and after 34 days of weather exposure test.

  3. Manufacture and performance of the thermal-bonding Micromegas prototype

    NASA Astrophysics Data System (ADS)

    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

    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.

  4. Spatial scale effects on hydrologic modeling of extensive green roofs in New York City

    NASA Astrophysics Data System (ADS)

    Finazzi, Marco; Hakimdavar, Raha; Barontini, Stefano; Ranzi, Roberto; Culligan, Patricia J.

    2013-04-01

    Effective implementation of green roofs technology as sustainable stormwater management tool requires comprehensive and quantitative information in terms of monitoring and prediction of its hydrologic performance during single rainfall events. Aiming at providing a robust simulation approach to understand the green roof behaviour during different storms, the efficency of one-dimensional hydrologic modeling was investigated, for three green roof systems at different spatial scale and characterized by the same green roof type. HYDRUS 1D model applied to solve the Richards equation with measured water retention curves and fitted hydraulic conductivity at saturation. The effect of the green roof area on the accuracy in predicting the subsurface outflow was investigated. A fairly large experimental dataset was available and let to compare simulated and observed green roofs performances on the basis of a statistical analysis and accounting for different storm size categories. As a result, the spatial scale of the green roof was found not to significantly affect the model accuracy in predicting the total outflow volume and the peak flow rate, particularly for storms characterized by rainfall depth lower than 25 mm. Peak discharge time and lag time resulted overestimated at all scales, but the discrepancy is lower for medium-sized rain events (ranging from 25 to 75 mm). The Nash-Sutcliffe Efficiency index indicates that the model is as more accurate in reproducing the effluent from the green roofs as greater is the scale of the systems, and as larger is the storm size.

  5. Analytical study of nozzle performance for nuclear thermal rockets

    SciTech Connect

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

    1991-01-01

    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.

  6. Thermal performance of microinverters on dual-axis trackers

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  7. Thermal dependence of sprint performance of the lizard Sceloporus occidentalis.

    PubMed

    Marsh, R L; Bennett, A F

    1986-11-01

    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

  8. Predictive Service Life Tests for Roofing Membranes

    NASA Astrophysics Data System (ADS)

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

    2002-09-01

    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.

  9. NEW TOOLS FOR ROOF SUPPORT EVALUATION AND DESIGN

    Microsoft Academic Search

    Steve Signer; Carl Sunderman

    Researchers at the National Institute for Occupational Safety and Health (NIOSH) have developed several new tools for evaluating roof support performance. A miniature data acquisition system (MIDAS) was developed that can collect readings from up to 16 strain gauges at regular time intervals and store the readings for later retrieval. Three LED lights change from green to yellow, then red,

  10. Controlled Alloying of CSM Roofing Membranes with Thermoplastic Resins

    Microsoft Academic Search

    Jimmie L. Stanton

    1996-01-01

    Single-ply roofing membranes based on CSM have been effective in commercial installation for over twenty years. Selective blending of thermoplastic resins, CPE (CM) and EVA, into a standard CSM formulation have been performed to evaluate the effect on calendering, accelerated aging and seaming ability. The effect of these resins on other physical properties are also characterized. Further, care must also

  11. 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...

  12. Standard Guide for Specifying Thermal Performance of Geothermal Power Systems

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    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.

  13. Performance contracting for parabolic trough solar thermal systems

    SciTech Connect

    Brown, H.; Hewett, R.; Walker, A. [National Renewable Energy Lab., Golden, CO (United States); Gee, R.; May, K. [Industrial Solar Technology, Golden, CO (United States)

    1997-12-31

    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 in an ever widening range of applications. Technical developments in materials and fabrication techniques reduce production cost and expand applications from swimming pool heating and service hot water, to higher-temperature applications such as absorption cooling and process steam. Simultaneously, new financing mechanisms such as a recently awarded US Department of Energy (DOE) Federal Energy Management Program (FEMP) indefinite quantity Energy Savings Performance Contract (Super ESPC) facilitate and streamline implementation of the technology in federal facilities such as prisons and military bases.

  14. Thermal control surfaces experiment (SOO69) flight systems performance

    NASA Technical Reports Server (NTRS)

    Wilkes, Donald R.; Hummer, Leigh L.

    1991-01-01

    The thermal control surfaces experiment (TCSE) was the most complex hardware system aboard the Long Duration Exposure Facility (LDEF). The TCSE system consists of a scanning spectroreflectometer that measured test samples mounted on a rotatable carousel assembly. A microprocessor based data system controlled all aspects of TCSE system operation. Power was provided by four primary batteries. Flight measurement and housekeeping data were stored on a tape recorder for postflight analysis. The TCSE is a microcosm of complex electro-optical payloads being developed by NASA, DoD, and the aerospace community. The TCSE provides valuable data on the performance of these systems in space. The TCSE flight system and its excellent performance on the LDEF mission are described. A few operational anomalies were encountered and are discussed. Initial post-flight tests show that the TCSE system remains functional although some degradation in the optical measurements were observed. The results of these tests are also presented.

  15. International Space Station power module thermal control system hydraulic performance

    SciTech Connect

    Goldberg, V. [Boeing North American, Inc., Canoga Park, CA (United States). Rocketdyne Div.

    1997-12-31

    The International Space Station (ISS) uses four photovoltaic power modules (PVMs) to provide electric power for the US On-Orbit Segment. The PVMs consist of photovoltaic arrays (PVAs), orbit replaceable units (ORUs), photovoltaic radiators (PVRs), and a thermal control system (TCS). The PVM TCS function is to maintain selected PVM components within their specified operating ranges. The TCS consists of the pump flow control subassembly (PFCS), piping system, including serpentine tubing for individual component heat exchangers, headers/manifolds, fluid disconnect couplings (FQDCs), and radiator (PVR). This paper describes the major design requirements for the TCS and the results of the system hydraulic performance predictions in regard to these requirements and system component sizing. The system performance assessments were conducted using the PVM TCS fluid network hydraulic model developed for predicting system/component pressure losses and flow distribution. Hardy-Cross method of iteration was used to model the fluid network configuration. Assessments of the system hydraulic performance were conducted based on an evaluation of uncertainties associated with the manufacturing and design tolerances. Based on results of the analysis, it was concluded that all design requirements regarding system performance could be met. The hydraulic performance range, enveloping possible system operating parameter variations was determined.

  16. Thermal Performance of a Cryogenic Fluid Management Cubesat Mission

    NASA Technical Reports Server (NTRS)

    Berg, J. J.; Oliveira, J. M.; Congiardo, J. F.; Walls, L. K.; Putman, P. T.; Haberbusch, M. S.

    2013-01-01

    Development for an in-space demonstration of a CubeS at as a Cryogenic Fluid Management (CFM) test bed is currently underway. The favorable economics of CubeSats make them appealing for technology development activity. While their size limits testing to smaller scales, many of the regimes relevant to CFM can still be achieved. The first demo flight of this concept, CryoCube®-1, will focus on oxygen liquefaction and low-gravity level sensing using Reduced Gravity CryoTracker®. An extensive thermal modeling effort has been underway to both demonstrate concept feasibility and drive the prototype design. The satellite will utilize both a sun- and earth-shield to passively cool its experimental tank below 115 K. An on-board gas generator will create high pressure gaseous oxygen, which will be throttled into a bottle in the experimental node and condensed. The resulting liquid will be used to perform various experiments related to level sensing. Modeling efforts have focused on the spacecraft thermal performance and its effects on condensation in the experimental node. Parametric analyses for both optimal and suboptimal conditions have been considered and are presented herein.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  18. High Performance Thermal Imaging Using Quantum Well Infrared Photodetector Arrays

    NASA Astrophysics Data System (ADS)

    Schneider, Harald

    2007-03-01

    Quantum well infrared photodetector (QWIP) technology has opened up new opportunities to realize focal plane arrays (FPA) for high-performance thermal imaging [1]. High thermal and spatial resolution, low 1/f noise, low fixed-pattern noise, and high pixel operability makes QWIP FPAs appropriate for many applications. Due to their narrow absorption bands with relative spectral widths ??/? of the order of 10%, QWIPs are particularly suitable for thermal imaging applications involving several atmospheric transmission bands or several colors within the same band. For dual-band/dual-color FPAs, QWIP technology has the unique property that the active region for the long-wavelength band is transparent for the short-wavelength band. In this talk, I will report on typical QWIP structures optimized for thermal imaging applications and on the performance of some state-of-the-art QWIP cameras which were jointly realized by the Fraunhofer-Institute for Applied Solid State Physics (Freiburg, Germany) and AIM Infrarot-Module GmbH (Heilbronn, Germany). Besides imagers for the 8 -- 12 ?m long-wavelength infrared (LWIR) and 3 -- 5 ?m mid-wavelength infrared (MWIR) regimes, these include a LWIR/MWIR dual-band QWIP FPA with 384x288 pixels which, at 6.8 ms integration time, exhibits a noise-equivalent temperature difference as low as 20.6 mK in the LWIR and 26.7 mK in the MWIR spectral bands. A specially designed diffraction grating is used for optical coupling of both spectral regimes. The array, which is based on a photoconductive QWIP for the MWIR and a photovoltaic ``low-noise'' QWIP for the LWIR, allows for synchronous and pixel-registered image acquisition in both bands. This functionality yields several advantages, including better distinction between target and background clutter, operation in a much wider range of ambient conditions, and the ability of remote absolute temperature measurement. [1] H. Schneider and H. C. Liu, Quantum Well Infrared Photodetectors: Physics and Applications, ISBN 3540363238, Springer Series in Optical Sciences Vol. 126, 2006.

  19. Thermal Performance of Cryogenic Multilayer Insulation at Various Layer Spacings

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley Louis

    2010-01-01

    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

  20. Topex Microwave Radiometer thermal control - Post-system-test modifications and on-orbit performance

    Microsoft Academic Search

    Edward I. Lin

    1993-01-01

    The Topex Microwave Radiometer has had an excellent thermal performance since launch. The instrument, however, went through a hardware modification right before launch to correct for a thermal design inadequacy that was uncovered during the spacecraft thermal vacuum test. This paper reports on how the initially obscure problem was tracked down, and how the thermal models were revised, validated, and

  1. Dynamic Thermal Management for High-Performance Storage Systems

    Microsoft Academic Search

    Youngjae Kim; Sudhanva Gurumurthi; Anand Sivasubramaniam

    2011-01-01

    Thermal-aware design of disk drives is important because high temperatures can cause reliability problems. Dynamic Thermal Management (DTM) techniques have been proposed to operate the disk at the average case temperature, rather than at the worse case by modulating the activities to avoid thermal emergencies. The thermal emergencies can be caused by unexpected events, such as fan-breaks, increased inlet air

  2. Evaluating Convex Roof Entanglement Measures

    NASA Astrophysics Data System (ADS)

    Tóth, Géza; Moroder, Tobias; Gühne, Otfried

    2015-04-01

    We show a powerful method to compute entanglement measures based on convex roof constructions. In particular, our method is applicable to measures that, for pure states, can be written as low order polynomials of operator expectation values. We show how to compute the linear entropy of entanglement, the linear entanglement of assistance, and a bound on the dimension of the entanglement for bipartite systems. We discuss how to obtain the convex roof of the three-tangle for three-qubit states. We also show how to calculate the linear entropy of entanglement and the quantum Fisher information based on partial information or device independent information. We demonstrate the usefulness of our method by concrete examples.

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

    SciTech Connect

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

    2007-06-04

    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.

  4. Integrated analysis of nuclear thermal rocket system performance

    SciTech Connect

    Buksa, J.J.; Rider, W.J.; Hall, M.; Perry, R.T.; Houts, M. (Los Alamos National Lab., NM (United States))

    1992-01-01

    As part of the Space Exploration Initiative (SEI), nuclear thermal rocket (NTR) engines will play a key transportation role. Although a number of tests of prismatic, solid-core nuclear engines were completed during the ROVER/NERVA program, the estimated cost of completing full-engine tests will severely limit the scope, duration, and number of any such tests in the future. Design optimization by test iteration is unlikely, and an emphasis on computational modeling is a cost-effective alternative. As a consequence of our responsibilities within the US Dept. of Energy's SEI efforts to develop key NTR technologies, Los Alamos National Laboratory (LANL) is developing the capability to design and verify the safety and performance of NTR systems. Because of the important role that computational modeling will play in the faster, better, and cheaper development of an NTR system, we are pursuing two paths of analysis. The first undertaking is the development of accurate separate-effects codes for design and analysis. Included in this category are thermal-hydraulic and radiation-transport codes. Our other endeavor, which is the focus of this paper, is to develop an advanced computational architecture that can be used to model the entire NTR system.

  5. Thermal performance of fiberglass and cellulose attic insulations

    SciTech Connect

    Wilkes, K.E.; Childs, P.W.

    1992-10-01

    A series of experiments has been completed on the thermal performance of fiberglass and cellulose attic insulations under winter conditions using an attic test module in a guarded hot box facility. Experiments with one type of loose-fill fiberglass insulation showed that the thermal resistance at large temperature differences (70 to 76{degrees}F) was about 35 to 50% less than at small temperature differences. The additional heat flow, attributed to natural convection, was effectively eliminated by applying a covering of fiberglass batts or a combination of a polyethylene film and fiberglass blankets. No significant convection was found either with fiberglass batts or with one type of loose-fill cellulose. Using the experimental data along with an attic model, the additional energy costs due to convection in the coldest climate investigated were estimated to be $0.025/ft{sup 2}yr to $0.028/ft{sup 2}yr at the R-19 level and $0.014/ft{sup 2}yr at the R-38 level. For the same conditions, annual energy savings due to upgrading insulation from the R-19 to the R-38 level were estimated to be $0.046/ft{sup 2}yr to $0.070/ft{sup 2}yr.

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

    Microsoft Academic Search

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

    2009-01-01

    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

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

    SciTech Connect

    Syd S. Peng

    2001-07-15

    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.

  8. THERMAL PERFORMANCE OF RADIOACTIVE MATERIAL PACKAGES IN TRANSPORT CONFIGURATION

    SciTech Connect

    Gupta, N.

    2010-03-04

    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.

  9. LARGO hot water system thermal performance test report

    NASA Technical Reports Server (NTRS)

    1978-01-01

    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.

  10. A comprehensive numerical model examining the thermal performance of airships

    NASA Astrophysics Data System (ADS)

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

    2011-11-01

    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.

  11. COMMIX analysis of four constant flow thermal upramp experiments performed in a thermal hydraulic model of an advanced LMR

    SciTech Connect

    Yarlagadda, B.S.

    1989-04-01

    The three-dimensional thermal hydraulics computer code COMMIX-1AR was used to analyze four constant flow thermal upramp experiments performed in the thermal hydraulic model of an advanced LMR. An objective of these analyses was the validation of COMMIX-1AR for buoyancy affected flows. The COMMIX calculated temperature histories of some thermocouples in the model were compared with the corresponding measured data. The conclusions of this work are presented. 3 refs., 5 figs.

  12. Thermal Performance of Microencapsulated Phase Material (MPCM) Slurry in a Coaxial Heat Exchanger

    E-print Network

    Yu, Kun

    2014-05-08

    transfer characteristics. Previous research in the field of MPCM's is also presented to help understand the effects of their thermal properties including density, viscosity, thermal conductivity, and specific heat on heat transfer performance. A detailed...

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

    E-print Network

    Park, Chan Hyun

    2012-07-16

    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...

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

    E-print Network

    Park, Chan Hyun

    2012-07-16

    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...

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

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

    SciTech Connect

    Syd S. Peng

    2003-10-15

    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.

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

    SciTech Connect

    Syd S. Peng

    2003-01-15

    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.

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

    Microsoft Academic Search

    Hassan E. S. Fath

    1995-01-01

    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

  19. HIGH-PERFORMANCE PHASECHANGE THERMAL ENERGY STORAGE USING SPHERICAL CAPSULES

    Microsoft Academic Search

    T. SAITOH; K. HIROSE

    1986-01-01

    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

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

    Microsoft Academic Search

    A. Synnefa; M. Santamouris; H. Akbari

    2007-01-01

    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

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

    SciTech Connect

    Kehrer, Manfred [ORNL

    2011-01-01

    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

  2. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 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...

  3. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 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...

  4. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 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...

  5. 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 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...

  6. 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 2010-07-01 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...

  7. 40 CFR 1037.140 - Curb weight and roof height.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Curb weight and roof height. 1037.140 Section 1037.140... § 1037.140 Curb weight and roof height. (a) Where applicable, a vehicle's curb weight and roof height are determined from nominal...

  8. 40 CFR 1037.140 - Curb weight and roof height.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Curb weight and roof height. 1037.140 Section 1037.140... § 1037.140 Curb weight and roof height. (a) Where applicable, a vehicle's curb weight and roof height are determined from nominal...

  9. 40 CFR 1037.140 - Curb weight and roof height.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Curb weight and roof height. 1037.140 Section 1037.140... § 1037.140 Curb weight and roof height. (a) Where applicable, a vehicle's curb weight and roof height are determined from nominal...

  10. 30 CFR 75.221 - Roof control plan information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...rib control system, including, if roof bolts are to be installed— (i) The length...torque or tension range for tensioned roof bolts. (10) When mechanically anchored tensioned roof bolts are used, the intervals at which test...

  11. 30 CFR 75.221 - Roof control plan information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...rib control system, including, if roof bolts are to be installed— (i) The length...torque or tension range for tensioned roof bolts. (10) When mechanically anchored tensioned roof bolts are used, the intervals at which test...

  12. 30 CFR 75.221 - Roof control plan information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...rib control system, including, if roof bolts are to be installed— (i) The length...torque or tension range for tensioned roof bolts. (10) When mechanically anchored tensioned roof bolts are used, the intervals at which test...

  13. 30 CFR 75.221 - Roof control plan information.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...rib control system, including, if roof bolts are to be installed— (i) The length...torque or tension range for tensioned roof bolts. (10) When mechanically anchored tensioned roof bolts are used, the intervals at which test...

  14. 30 CFR 75.213 - Roof support removal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (2) Prior to the removal of roof bolts, temporary support shall be installed as close as practicable to each roof bolt being removed. (d) Temporary supports...not be removed where— (1) Roof bolt torque or tension measurements or...

  15. 30 CFR 75.213 - Roof support removal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (2) Prior to the removal of roof bolts, temporary support shall be installed as close as practicable to each roof bolt being removed. (d) Temporary supports...not be removed where— (1) Roof bolt torque or tension measurements or...

  16. 30 CFR 75.213 - Roof support removal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (2) Prior to the removal of roof bolts, temporary support shall be installed as close as practicable to each roof bolt being removed. (d) Temporary supports...not be removed where— (1) Roof bolt torque or tension measurements or...

  17. 30 CFR 75.213 - Roof support removal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (2) Prior to the removal of roof bolts, temporary support shall be installed as close as practicable to each roof bolt being removed. (d) Temporary supports...not be removed where— (1) Roof bolt torque or tension measurements or...

  18. 30 CFR 75.221 - Roof control plan information.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...rib control system, including, if roof bolts are to be installed— (i) The length...torque or tension range for tensioned roof bolts. (10) When mechanically anchored tensioned roof bolts are used, the intervals at which test...

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

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Birur, Gajanana

    2004-01-01

    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.

  20. Assessment of the performance of ventilated floor thermal storage systems

    SciTech Connect

    Holmes, M.J.; Wilson, A. [Ove Arup Partnership, London (United Kingdom)

    1996-11-01

    Ventilation of the building fabric is one method to achieve storage of heat and cold. A popular European method is to pass air through ducts within the floor and ceiling slabs. That air can either be at the outside air temperature or from the air-conditioning plant. In the former case, the intention is to transfer cold from night to day and in the latter to reduce peak loads by cooling the room surfaces and thus increase comfort via radiant cooling. The performance of such systems can be assessed by comparison with direct nighttime ventilation (say, through windows) and traditional air-conditioning systems operating during occupancy. The paper presents the development of a numerical model of a ventilated floor slab for use in a dynamic thermal model and the application of that model to a current design project. Energy consumption cannot be ignored; however, a complete analysis of the implication of storage systems would be a major paper. This paper therefore considers the main energy implications associated with slab storage systems.

  1. High-performance MWIR dual bandpass filter for thermal imaging

    NASA Astrophysics Data System (ADS)

    Hendrix, Karen D.; Bergeron, Adam; Favot, David L.

    2009-05-01

    Bandpass filters transmitting the 3.5 to 5.0?m atmospheric window while simultaneously blocking the 4.3?m CO2 absorption band are in demand. However, realization of these dual bandpass filters is challenging from the standpoint of coating design, material selection, and manufacturing process. JDSU's Ucp-1 magnetron sputtering platform is ideally suited to the production of these types of filters. It enables the use of coating materials with higher transmission and lower temperature shifts than conventional (i.e. thermally evaporated) MWIR materials. Ucp-1 also has excellent layer thickness control, which allows complex designs to be realized. The performance of a dual bandpass filter manufactured for AFRL as part of their "Exploration of Novel Band-pass Filter Designs" program is discussed. The filter achieved average transmission in the passbands of greater than 94% with filter slopes of 1.1% or less. Blocking of the CO2 band was less than 1%, and the below and above band blocking was less than 0.1%. All of the filter requirements were met over the temperature range of 77K to room ambient. We also discuss the results achieved in extending the above approach to the design and manufacture of a quadruple bandpass filter (with passbands centered at 1.23, 1.6, 2.2, and 3.75?m).

  2. Effects of Sand-Bentonite Backfill Materials on the Thermal Performance of Borehole Heat Exchangers

    Microsoft Academic Search

    Huajun Wang; Yahui Cui; Chengying Qi

    2013-01-01

    The paper presents a quantitative analysis of the effects of sand-bentonite backfill materials on the thermal performance of borehole heat exchangers (BHEs). Laboratory thermal probe tests were conducted to measure the thermal conductivity of sand-bentonite mixtures under different mixed ratios. Based on microscopic observations, the mechanism of bentonite affecting heat conduction between the sand grains was analyzed. Then, field tests

  3. Effect of mold compound thermal conductivity on IC package thermal performance

    Microsoft Academic Search

    M. Michael; L. Nguyen

    1992-01-01

    The authors discuss the effects of varying the thermal conductivity of epoxy molding compounds on the thermal behavior of plastic IC packages. Thermal conductivity values were estimated for various filler types (fused and crystalline silica, aluminum oxide, aluminum and boron nitride, silicon carbide, and diamond), sizes, and distribution. Values for the resulting composites were used in determining the effectiveness of

  4. Lightweight, self-ballasting photovoltaic roofing assembly

    DOEpatents

    Dinwoodie, Thomas L. (Berkeley, CA)

    1998-01-01

    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.

  5. Lightweight, self-ballasting photovoltaic roofing assembly

    DOEpatents

    Dinwoodie, T.L.

    1998-05-05

    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.

  6. Extruded metal solar collector roofing shingle

    Microsoft Academic Search

    J. A. Jr

    1978-01-01

    An extruded aluminum planar roofing shingle is described with a structural capability of spanning over six feet which incorporates an integral tube which projects from its lower surface, the shingles being mounted in edge over-lapping, parallel array fashion across laterally spaced, inclined roof rafters of a building structure and being interlocked at said edges, each shingle extending the full length

  7. Metal Roofing in a "Class" by Itself.

    ERIC Educational Resources Information Center

    Nimtz, Paul D.

    1990-01-01

    The structural standing seam roof has the advantages of ease of application, low maintenance, and low life-cycle costs. Explains and illustrates how the system's concealed clip attachments are designed so that the roof panels can expand and contract independently of the insulation. (MLF)

  8. Roofs--Their Problems and Solutions.

    ERIC Educational Resources Information Center

    Swentkofske, Carl J.

    Most roofs are meant to withstand the elements for a period of 20 years; to achieve this goal, however, school officials must believe in a dedicated maintenance program and sell it to their superiors and school boards. Establishment of a school district roof maintenance program is explained. Job qualifications and training methods for an inhouse…

  9. A ROOFING TILE FOR NATURAL COOLING

    E-print Network

    SUNGUARD: A ROOFING TILE FOR NATURAL COOLING Prepared For: California Energy Commission Energy (FAR) SUNGUARD: A ROOFING TILE FOR NATURAL COOLING EISG AWARDEE PowerLight Corporation 2954 San Pablo,000 for promising proof-of-concept energy research. PIER funding efforts are focused on the following six RD

  10. 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

    Not Available

    1994-02-01

    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.

  11. Sloshing impact in roofed tanks

    SciTech Connect

    Uras, R.A. [Argonne National Lab., IL (United States). Reactor Engineering Div.

    1995-12-31

    A large number of high-level waste (HLW) storage tanks exists in various tank farms. Seismic activities at those locations may cause significant sloshing in HLW tanks. These tanks are covered to avoid any spilling during large amplitude earthquakes. However, large amplitude sloshing may result in impact on the cover or the roof of the tank. Hence, a better understanding of the impact phenomenon is necessary to assess the safety of the tanks currently in existence, and to establish design guidelines for future designs. A pressure based formulation is derived to model sloshing impact in roofed tanks. It is incorporated into Argonne`s in-house finite element code FLUSTR-ANL. A numerical test case with a harmonic input excitation is studied. The simulation results indicate that linear behavior is preserved beyond the first impact, and some mesh distortion is observed following a stronger second impact. During the impact, the displacement of the contacting surface nodes remains constant, and the velocities are reduced to zero. An identification of impacting nodes is possible from the dynamic pressures induced in surface elements.

  12. Integrated roof wind energy system

    NASA Astrophysics Data System (ADS)

    Suma, A. B.; Ferraro, R. M.; Dano, B.; Moonen, S. P. G.

    2012-10-01

    Wind is an attractive renewable source of energy. Recent innovations in research and design have reduced to a few alternatives with limited impact on residential construction. Cost effective solutions have been found at larger scale, but storage and delivery of energy to the actual location it is used, remain a critical issue. The Integrated Roof Wind Energy System is designed to overcome the current issues of urban and larger scale renewable energy system. The system is built up by an axial array of skewed shaped funnels that make use of the Venturi Effect to accelerate the wind flow. This inventive use of shape and geometry leads to a converging air capturing inlet to create high wind mass flow and velocity toward a vertical-axis wind turbine in the top of the roof for generation of a relatively high amount of energy. The methods used in this overview of studies include an array of tools from analytical modelling, PIV wind tunnel testing, and CFD simulation studies. The results define the main design parameters for an efficient system, and show the potential for the generation of high amounts of renewable energy with a novel and effective system suited for the built environment.

  13. Experimental investigations of fluid dynamic and thermal performance of nanofluids

    NASA Astrophysics Data System (ADS)

    Kulkarni, Devdatta Prakash

    The goal of this research was to investigate the fluid dynamic and thermal performance of various nanofluids. Nanofluids are dispersions of metallic nanometer size particles (<100 nm) into the base fluids. The choice of base fluid is an ethylene or propylene glycol and water mixture in cold regions. Initially the rheological characterization of copper oxide (CuO) nanofluids in water and in propylene glycol was performed. Results revealed that higher concentrations of CuO nanoparticles (5 to 15%) in water exhibited time-independent pseudoplastic and shear-thinning behavior. Lower concentrations (1 to 6%) of CuO nanofluids in propylene glycol revealed that these nanofluids behaved as Newtonian fluids. Both nanofluids showed that viscosity decreased exponentially with increase in temperature. Subsequent correlations for viscosities as a function of volume concentration and temperature were developed. Effects of different thermophysical properties on the Prandtl number of CuO, silicon dioxide (SiO2) and aluminum oxide (A12O 3) nanofluids were investigated. Results showed that the Prandtl number increased with increasing volume concentrations, which in turn increased the heat transfer coefficients of the nanofluids. Various nanofluids were compared for their heat transfer rates based on the Mouromtseff number, which is a Figure of Merit for heat transfer fluids. From this analysis, the optimal concentrations of nanoparticles in base fluids were found for CuO-water nanofluids. Experiments were performed to investigate the convective heat transfer enhancement and pressure loss of CuO, SiO2 and A12O 3 nanofluids in the turbulent regime. The increases in heat transfer coefficient by nanofluids for various volume concentrations compared to the base fluid were determined. Pressure loss was observed to increase with nanoparticle volume concentration. It was observed that an increase in particle diameter increased the heat transfer coefficient. Calculations showed that application of nanofluids in heat exchangers in buildings could result in volumetric flow reduction, reduction in the mass flow rate and size, and pumping power savings. Experiments on a diesel electric generator with nanofluids showed a reduction of cogeneration efficiency due to the decrease in specific heat compared to the base fluids. However, it was found that the efficiency of the waste heat recovery heat exchanger increased for nanofluids.

  14. Mechanisms governing the performance of thermal barrier coatings

    Microsoft Academic Search

    P. K. Wright; A. G. Evans

    1999-01-01

    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.

  15. Green roof impact on the hydrological cycle components

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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.

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

    SciTech Connect

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

    2013-10-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

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

    ERIC Educational Resources Information Center

    Christensen, G.; And Others

    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…

  20. Thermal Performance Prediction of QFN Packages using Artificial Neural Network (ANN)

    Microsoft Academic Search

    R. C. Law; R. Cheang; Y. W. Tana; I. A. Azid

    2006-01-01

    The thermal performance of QFN with body sizes ranging from 3 mm times 3 mm to 9 mm times 9 mm with various lead counts were modeled on FR4 printed circuit board using a solid model finite element simulation tools (ANSYS). The thermal performance obtained using FEA agrees well with the experiment data (within 12%). A series of data with

  1. Thermal performance of myristic acid as a phase change material for energy storage application

    Microsoft Academic Search

    Ahmet Sar?; Kamil Kaygusuz

    2001-01-01

    Thermal performance and phase change stability of myristic acid as a latent heat energy storage material has been studied experimentally. In the experimental study, the thermal performance and heat transfer characteristics of the myristic acid were tested and compared with other studies given in the literature. In the present study is included some parameters such as transition times, temperature range,

  2. Impact of moisture\\/reflow induced delaminations on integrated circuit thermal performance

    Microsoft Academic Search

    T. R. Conrad; R. L. Shook

    1994-01-01

    Ambient moisture uptake in plastic surface mount IC packages can cause delamination of critical internal surfaces within the package during reflow assembly. Delaminations can result in reduced thermal cycling life performance or provide for a pathway for the ingress of chemicals and contaminates. The effects that moisture\\/reflow induced delaminations can have on the thermal performance of plastic packaged ICs are

  3. Towards a methodology for the characterization of fire resistive materials with respect to thermal performance modelsz

    Microsoft Academic Search

    Dale P. Bentzn; Kuldeep R. Prasad; Jiann C. Yang

    SUMMARY A methodology is proposed for the characterization of fire resistive materials with respect to thermal performance models. Typically in these models, materials are characterized by their densities, heat capacities, thermal conductivities, and any enthalpies (of reaction or phase changes). For true performance modelling, these thermophysical properties need to be determined as a function of temperature for a wide temperature

  4. Application of spatial frequency response as a criterion for evaluating thermal imaging camera performance

    Microsoft Academic Search

    Andrew Lock; Francine Amon

    2008-01-01

    Police, firefighters, and emergency medical personnel are examples of first responders that are utilizing thermal imaging cameras in a very practical way every day. However, few performance metrics have been developed to assist first responders in evaluating the performance of thermal imaging technology. This paper describes one possible metric for evaluating spatial resolution using an application of Spatial Frequency Response

  5. Thermal Performance Correlation of Horizontal Closed-Loop Oscillating Heat Pipes

    Microsoft Academic Search

    Piyanun Charoensawan; Pradit Terdtoon

    2007-01-01

    The thermal performance of a closed-loop oscillating heat pipe which operates at horizontal orientation (Horizontal closed-loop oscillating heat pipe, HCLOHP) was dimensionally analyzed to formulate the empirical correlation. The various dimensionless groups which were supposed to influence the thermal performance of a HCLOHP was considered coupling with the quantitative results of the heat transfer characteristics of HCLOHP. These available results

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

    Microsoft Academic Search

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

    1981-01-01

    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

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

    NASA Technical Reports Server (NTRS)

    Wales, R. O. (editor)

    1981-01-01

    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.

  8. Laboratory measurements of the drying rates of low-slope roofing systems

    SciTech Connect

    Desjarlais, A.O.; Kyle, D.M.; Childs, P.W.; Christian, J.E.

    1994-05-01

    The service life of a roofing system typically ends when excessive amounts of water have entered the system. Roofing professionals determine whether the existing failed roofing system can be repaired or salvaged by recovering. A key element in this decision is whether the accumulated water will be able to leave the roofing system in a time frame that will prevent irreparable structural damage. There are several combined heat and mass transfer models that can be used to predict drying times for low-slope roofing systems. Very little experimental data exists that can be used to validate the performance of these models. To satisfy these needs, a series of laboratory experiments has been performed. Five test panels, comprised of a plywood deck, four types of roofing insulation, and a single ply membrane were installed in a climate simulator. The test panels were outfitted with temperature sensors and heat flux transducers, and were mounted on load cells. Water was added to the test panels and they were subjected to external diurnal cycles representative of summer and winter conditions for a southern US continental climate. The load cells supplied continuous records of the weights of the test panels; these data were used to compute the drying rates of the test panels. When these experiments were completed, the test panels were ``recovered`` with different thicknesses of insulation and the environmental conditions were reapplied to the test panels. This paper reports on the design and performance of these experiments. The data compiled during these tests supply insight into the effects of meteorological conditions, insulation R-value, insulation water vapor permeance, and roof recover on the rate that water will be removed from low-slope roofing systems.

  9. Thermal Insulation Performance in the Process Industries: Facts and Fallacies 

    E-print Network

    Tye, R. P.

    1985-01-01

    The efficient use of thermal insulation materials and systems for design of cryogenic and elevated temperature process applications depends upon a reliable knowledge of their properties. Properties determined under idealized laboratory conditions...

  10. Thermal performance of phase change wallboard for residential cooling application

    Microsoft Academic Search

    Helmut E. Feustel; Corina Stetiu

    1997-01-01

    Cooling of residential California buildings contributes significantly to electrical consumption and peak power demand mainly due to very poor load factors in milder climates. Thermal mass can be utilized to reduce the peak-power demand, downsize the cooling systems, and\\/or switch to low-energy cooling sources. Large thermal storage devices have been used in the past to overcome the shortcomings of alternative

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

    PubMed

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

    2014-05-01

    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

  12. Measuring mine roof bolt strains

    SciTech Connect

    Steblay, B.J.

    1986-07-22

    A method is described of measuring the strain in mine roof bolts comprising the steps of: machining a flat portion on the head of the bolt before loading; drilling a reflector hole radially through the diameter of the bolt at a predetermined distance from the bolt head before loading, the ratio of the diameter of the hole to the diameter of the bolt being less than 0.10 to prevent weakening of the loaded bolt; generating an ultrasonic pulse at the flat portion after loading; measuring the time of travel of the ultrasonic pulse reflected from the hole, which increases as the bolt is loaded; and correlating the time measurement of the strain in the bolt.

  13. Design of roof bolt patterns for jointed rock

    Microsoft Academic Search

    1974-01-01

    The objectives of this research were to determine the stability relationships of coal mine roof rocks that are cut by fractures of intersecting joints, with and without roof bolts, under various sets of conditions and to develop criteria for the design of roof bolt systems for such roofs. The problem was studied by mathematical finite element models and by laboratory

  14. The performance of adobe and other thermal mass materials in residential buildings

    SciTech Connect

    Robertson, D.

    1986-01-01

    This paper reviews the history and current status of thermal mass research, and national, state, and local codes with respect to thermal mass; and offers specific recommendations on how best to use thermal mass for energy efficiency and comfort. Much of the material comes directly from the Southwest Thermal Mass Study (SWTMS), an experimental research study on the thermal performance of adobe conducted at Tesuque Pueblo, New Mexico, in the early 1980s. The focus is primarily on residential construction, although the theory and most of the recommendations apply to small commercial buildings as well.

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

    Microsoft Academic Search

    Joseph Khedari; Jongjit Hirunlabh; Tika Bunnag

    1997-01-01

    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

  16. Analytical prediction of the performance of an air photovoltaic/thermal flat-plate collector

    SciTech Connect

    Raghuraman, P.

    1980-04-30

    A one-dimensional analysis developed by MIT Lincoln Laboratory predicts the electrical and thermal performance of an air photovoltaic/thermal flat-plate collector. The analysis compares well with test measurements, predicting the thermal efficiency to within 2 percent. From the analysis, the poor thermal performance of the collector is attributable, in part, to the large undulations of the cell/silicone pottant surface in contact with the flowing air that results in less effective convective heat-transfer areas between the cell and the air.

  17. Metal and nutrient dynamics on an aged intensive green roof.

    PubMed

    Speak, A F; Rothwell, J J; Lindley, S J; Smith, C L

    2014-01-01

    Runoff and rainfall quality was compared between an aged intensive green roof and an adjacent conventional roof surface. Nutrient concentrations in the runoff were generally below Environmental Quality Standard (EQS) values and the green roof exhibited NO3(-) retention. Cu, Pb and Zn concentrations were in excess of EQS values for the protection of surface water. Green roof runoff was also significantly higher in Fe and Pb than on the bare roof and in rainfall. Input-output fluxes revealed the green roof to be a potential source of Pb. High concentrations of Pb within the green roof soil and bare roof dusts provide a potential source of Pb in runoff. The origin of the Pb is likely from historic urban atmospheric deposition. Aged green roofs may therefore act as a source of legacy metal pollution. This needs to be considered when constructing green roofs with the aim of improving pollution remediation. PMID:24017999

  18. THE THERMAL 15 RELIEF WELL AND PRODUCTION PERFORMANCE OF THE THERMAL SHALLOW RESERVOIR

    SciTech Connect

    Mogen, P.; Maney, J.

    1985-01-22

    Thermal 15 was drilled in November, 1983, to a TD of 700 feet. A steam entry encountered at 490 feet was found to communicate with the high-permeability upflow zone of the Thermal Shallow Reservoir. A low-flow-rate, higher-pressure steam entry at 600 feet was not detected while drilling but was indicated during a subsequent spinner survey. The pressure, flowrate, and enthalpy of the five wells completed in the upflow zone, including the Thermal 4 blowout, were monitored and recorded over a four month period before, during and after Thermal 15 was drilled. It was found that the Thermal 4 blowout communicates with the upflow zone of the Thermal Shallow Reservoir, the Thermal 4 flowrate is controlled by the shallow reservoir pressure, and the high permeability of the upflow zone allows such strong interference effects that three of the four commercial production wells will maximize production from this reservoir. A simple model was developed which describes the pressure-production characteristics of the reservoir over the normal range of operating conditions.

  19. Titanium mesh reconstruction of orbital roof fracture with traumatic encephalocele: a case report and review of literature.

    PubMed

    Mokal, Nitin J; Desai, Mahinoor F

    2012-03-01

    Orbital roof fractures are rare. Traumatic encephaloceles in the orbital cavity are even rarer, with only 21 cases published to date. Orbital roof fractures are generally encountered in males between 20 and 40 years of age following automobile collision. We report a case of an orbital roof fracture with traumatic encephalocele into the left orbit. Early diagnosis and treatment are very important because the raised intraorbital pressure may irreversibly damage the optic nerve. Computed tomography with 3-D reconstruction, the imaging modality of choice, showed the displaced fracture fragment deep into the orbit. Reconstruction of the orbital roof should be performed in every case. We used an extracranial approach to elevate the fracture with titanium mesh to stabilize the fragment. The cosmetic results were excellent but delay in treatment was responsible for delayed recovery of vision. The case report is followed by a brief overview of orbital roof fractures including pertinent review of literature. PMID:23450105

  20. Thermal vacuum chamber shroud performance with gaseous nitrogen cooling

    NASA Technical Reports Server (NTRS)

    Farmer, R. A.

    1972-01-01

    The results are presented for calculations of shroud surface temperature for various flow rates of gaseous nitrogen through the liquid nitrogen shrouds of a large thermal vacuum chamber. The conditions imposed provide conservative bounds for Mars surface simulation inside the chamber during thermal testing of an appropriate test object. It is shown that the shroud surfaces seen by the object can be held within an acceptable temperature range by providing a reasonable flow of gaseous nitrogen to the shrouds at a reasonable pressure, and that no change to the present shroud system need be made which would affect its suitability for liquid nitrogen cooling.

  1. Thermal performance of windows having high solar transmittance

    SciTech Connect

    Rubin, M.; Selkowitz, S.

    1981-07-01

    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.

  2. Advanced Low Conductivity Thermal Barrier Coatings: Performance and Future Directions (Invited paper)

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2008-01-01

    Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and performance will be emphasized. Advanced thermal barrier coatings have been developed using a multi-component defect clustering approach, and shown to have improved thermal stability and lower conductivity. The coating systems have been demonstrated for high temperature combustor applications. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the toughened thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion, impact and high heat-flux damage mechanisms of the thermal barrier coatings will also be described.

  3. Performance of thermal barrier coatings in high heat flux environments

    Microsoft Academic Search

    ROBERT A. MILLER; CHRISTOPHER C. BERNDT

    1984-01-01

    Thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch. Analysis of the specimen heating rates indicates that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 \\

  4. High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems

    SciTech Connect

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

    2007-06-01

    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.

  5. Analysis of performance of dynamic thermal diffusion chamber

    Microsoft Academic Search

    G. N. Lipantov; G. L. Shingarev

    1984-01-01

    Using a thermal diffusion chamber, the influence of sampling and thermo-and diffusiophoretic effects on the results of atmospheric condensation nuclei activity measurements was studied. Under certain temperatures and air humidity there occurs supersaturation on the chamber inlet exceeding that of supersaturation estimated for linear distribution of temperature and vapor concentration. Thermo-and diffusiophoretic effects may result in 20% errors under the

  6. Performance characteristics of pulsating heat pipes as integral thermal spreaders

    Microsoft Academic Search

    Honghai Yang; Sameer Khandekar; Manfred Groll

    2009-01-01

    In the recent past, Pulsating Heat Pipes (PHPs) have attracted the attention of many researchers as viable candidates for enhanced heat transfer through passive two-phase heat transfer mechanism. Although a complete theoretical understanding of operational characteristics of this device is not yet achieved, there are many emerging niche applications, ranging from electronics thermal management to compact heat exchangers. For a

  7. 30 CFR 75.204 - Roof bolting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (e)(1) The diameter of finishing bits shall be within a tolerance of plus or minus...anchor used. (2) When separate finishing bits are used, they shall be distinguishable from other bits. (f) Tensioned roof bolts....

  8. 30 CFR 75.204 - Roof bolting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (e)(1) The diameter of finishing bits shall be within a tolerance of plus or minus...anchor used. (2) When separate finishing bits are used, they shall be distinguishable from other bits. (f) Tensioned roof bolts....

  9. 30 CFR 75.204 - Roof bolting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (e)(1) The diameter of finishing bits shall be within a tolerance of plus or minus...anchor used. (2) When separate finishing bits are used, they shall be distinguishable from other bits. (f) Tensioned roof bolts....

  10. How To Choose the Right Roofing System.

    ERIC Educational Resources Information Center

    Carl, David

    2001-01-01

    Lists the factors that must be considered when specifying a roof for an existing or new facility. Factors discussed include cost, longevity, value of operations, warranties, building structure and design, and old vs. new system compatibility. (GR)

  11. Roof Coating Procedures and Their Productivity Gains

    E-print Network

    Bonaby, J.; Schaub, D.

    2006-01-01

    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...

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

    E-print Network

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

    2006-01-01

    Moisture and humidity; attic ventilation case studies; monitoring and analysis of energy data; data project case studies; building envelope issues; glazing; residential housing design; institutional, government, and utility energy policy; energy...

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

  14. Measured Energy Savings from the Application of Reflective Roofs in 3 AT and T Regeneration Buildings

    SciTech Connect

    Akbari, Hashen; Rainer, Leo

    2000-11-01

    Energy use and environmental parameters were monitored in three AT and T regeneration buildings during the summer of 2000. These buildings are constructed with concrete and are about 14.9 m2 (160 f2; 10x16 ft)in size. The buildings were initially monitored for about 1 1/2 months to establish a base condition. Then, the roofs of the buildings were painted with a white coating and the monitoring was continued. The original roof reflectances were about 26 percent; after the application of roof coatings the reflectivities increased to about 72 percent. In two of these buildings, we monitored savings of about 0.5kWh per day (8.6 kWh/m2 [0.8 kWh/ft2]). The third building showed a reduction in air-conditioning energy use of about 13kWh per day. These savings probably resulted from the differences in the performance (EER) of the two dissimilar AC units in this building. The estimated annual savings for two of the buildings are about 125kWh per year; at a cost of dollar 0.1/kWh, savings are about dollar 12.5 per year. Obviously, it costs significantly more than this amount to coat the roofs with reflective coating, particularly because of the remote location of the buildings. However, since the prefabricated roofs are already painted green at the factory, painting them with white (reflective) color would bring no additional cost. Hence the payback time for having reflective roofs is nil, and the reflective roofs save an accumulated 370kWh over 30 years of the life of the roof.

  15. Roof Coating Procedures and Their Productivity Gains 

    E-print Network

    Bonaby, J.; Schaub, D.

    2006-01-01

    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... benefit of the installation of different roof coating technologies and comparable application procedures of these technologies are ambiguous. The focal point of this research is to determine the effective correlation between various commercially...

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

    NASA Technical Reports Server (NTRS)

    Humphries, W. R.

    1974-01-01

    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.

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

    PubMed

    Razzaghmanesh, M; Beecham, S

    2014-11-15

    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

  18. Analysis of DOE s Roof Savings Calculator with Comparison to other Simulation Engines

    SciTech Connect

    New, Joshua Ryan [ORNL; Huang, Yu (Joe) [White Box Technologies; Levinson, Ronnen [Lawrence Berkeley National Laboratory (LBNL); Mellot, Joe [The Garland Company; Sanyal, Jibonananda [ORNL; Childs, Kenneth W [ORNL

    2014-01-01

    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 based on national averages 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 and attic configurations including different roof slopes, above sheathing ventilation, radiant barriers, low-emittance surfaces, HVAC duct location, duct leakage rates, multiple layers of building materials, ceiling and deck insulation levels, and other parameters. A base case and energy-efficient alternative 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. However, RSC gives different energy savings estimates than previous cool roof simulation tools so more thorough software and empirical validation proved necessary. This report consolidates much of the preliminary analysis for comparison of RSC s projected energy savings to that from other simulation engines.

  19. Analytical predictions of liquid and air photovoltaic/thermal flat-plate collector performance

    SciTech Connect

    Raghuraman, P.; Hendrie, S.D.

    1980-01-01

    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 analyses account for the temperature difference between the primary insolation absorber (the photovoltaic cells) and the secondary absorber (a thermal absorber flat plate). 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.

  20. Thermal performance of sub-atmospheric loop thermosyphon with and without enhanced boiling surface

    Microsoft Academic Search

    S. W. Chang; K. F. Chiang; C.-C. Huang

    2012-01-01

    This experimental study comparatively examines the thermal performances of two-phase loop thermosyphons (TPLP) with and without enhanced boiling surface at sub-atmospheric pressures. The boiling instabilities along with the constituent and total thermal resistances of these TPLPs are analyzed with the aid of boiling flow structures imaged at sub-atmospheric pressures. Boiling heat flux (Q) and thermal resistance of condenser (Rth,con) are

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

    Microsoft Academic Search

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

    2010-01-01

    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

  2. Prediction of the thermal performance of horizontal-coupled ground-source heat exchangers

    Microsoft Academic Search

    Yupeng Wu; Guohui Gan; Raquel Garcia Gonzalez; Anne Verhoef; Pier Luigi Vidale

    2011-01-01

    The thermal performance of a horizontal-coupled ground-source heat pump system has been assessed both experimentally and numerically in a UK climate. A numerical simulation of thermal behaviour of the horizontal-coupled heat exchanger for combinations of different ambient air temperatures, wind speeds, refrigerant temperature and soil thermal properties was studied using a validated 2D transient model. The specific heat extraction by

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

    E-print Network

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

    2013-01-01

    and then the database is used to train an artificial neural network (ANN) for predicting of the performance. Then, the LHTES's outlet air-temperature function is integrated into the TRNSYS building thermal response model. The trained ANN is able to improve...

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

    SciTech Connect

    Syd S. Peng

    2004-04-15

    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.

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

    NASA Technical Reports Server (NTRS)

    Ko, William L.

    2004-01-01

    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.

  6. Prediction of shell and tube thermal energy store performance

    SciTech Connect

    Hofmann, J. [Randcoal Pty Ltd., Johannesburg (South Africa). Dept. of Engineering; Smith, G.D.J. [Univ. of Natal, Durban (South Africa). Dept. of Mechanical Engineering

    1995-12-31

    A one-dimensional transient model has been developed to assist with the design of a shell and tube thermal energy storage unit. The model takes into account the various geometric features of the unit, the latent heat during liquid/solid phase change and the sensible heat storage in the shell, tube material and baffle plates. The model was solved using a multistep predictor-corrector method. The effect of changes to tube diameter, tube length, baffle spacing and PCM fraction were investigated. Certain of the theoretical predictions were compared with experimental results obtained from an 80 MJ thermal energy store using a wax, with a 62 C melting point, as the phase change material. Predicted temperatures were within 8 C of the measured values over the entire charge/discharge periods.

  7. Thermal performance of an elastomer subjected to radiant heating

    NASA Astrophysics Data System (ADS)

    Hender, D. R.; Cross, C. R.

    1981-06-01

    This paper describes a test technique and modeling procedure that has been developed to provide an accurate thermal response model for a one-dimensional subliming ablation analysis code. Thin foil thermocouples are molded into the elastomer at different depths and tests are run at a broad range of radiant heat rates, thereby developing accurate temperature response data. Several test runs are made at a low heat flux to enable verification or adjustment of thermophysical properties measured in the laboratory. The modeling procedure consists of establishing a set of thermal properties and ablation parameters that match the test data over the range of test conditions. An NBR/EPDM blend material was used in the testing and modeling reported in this paper.

  8. Flightweight radiantly and actively cooled panel: thermal and structural performance

    Microsoft Academic Search

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

    1982-01-01

    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

  9. Thermal Insulation Performance in the Process Industries: Facts and Fallacies

    E-print Network

    Tye, R. P.

    be eliminated or reduced signi ficantly. Recently there have been significant advances in the development of improved refractory fibers which have made this possible. These newer Nextel~* 312 and 440 Ceramic Ultrafibers are basi cally aluminosilicates....om temperature air at increasing velocities. The type of joint has some effect on the overall thermal transmittance. However, IIIJch larger effects were found by reducing the effec tiveness of a joint and so making it m:>re suscep tible to air movement...

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  11. Effects of different multiple PCMs on the performance of a latent thermal energy storage system

    Microsoft Academic Search

    Ming Fang; Guangming Chen

    2007-01-01

    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

  12. Improving accuracy and flexibility of ASTM D 5470 for high performance thermal interface materials

    Microsoft Academic Search

    D. Kearns

    2003-01-01

    The thermal demands of current and next generation microprocessors have driven requirements for thermal interface materials (TIMs) to the point where reliable vendor data is often not available. Vendors are struggling to meet customers needs. Existing industry test standards were intended for electrical insulation materials and cannot provide accurate data for todays high performance TIMs. Manufacturers are forced to accept

  13. A NEW DYNAMIC TEST METHOD OF THERMAL PERFORMANCE FOR EVACUATED TUBE SOLAR COLLECTOR

    Microsoft Academic Search

    Bowei Wang; Zhifeng Wang; Xing Li; Yi Ruan

    2000-01-01

    In the present paper, the thermal performance of evacuated tube solar collector is investigated. A new dynamic model for testing solar collector is analyzed. The model is derived from thermal energy balance and solved by transfer function. In the model the collector is like as a system, the outlet temperature ( Tfo ) is the system output, the other variables:

  14. The effect of vertical air gaps to thermal transmittance of horizontal thermal insulating layer

    Microsoft Academic Search

    Jolanta Šadauskiene; Andrius Buska; Ar?nas Burlingis; Raimondas Bli?džius; Albinas Gailius

    2009-01-01

    In order to reduce the amounts of work at the construction site, single?ply dual density thermal insulating roofing boards are used with increasing frequency for thermal insulation of flat roofs. In this case, the joints between boards are not overlapped by the other ply over it; therefore gaps of varying width form between the sides of the boards through the

  15. Sloshing impact in roofed tanks

    SciTech Connect

    Uras, R.A.

    1995-07-01

    A large number of high-level waste (HLW) storage tanks exists in various tank farms. Seismic activities at those locations may cause significant sloshing in HLW tanks. These tanks are covered to avoid any spilling during large amplitude earthquakes. However, large amplitude sloshing may result in impact on the cover or the roof of the tank. Hence, a better understanding of the impact phenomenon is necessary to assess the safety of the tanks currently in existence, and to establish design guidelines for future designs. A pressure based formulation is derived to model sloshing impact in roared tanks. It is incorporated into Argonne`s in-house finite element code FLUSTR-ANL. A numerical test case with a harmonic input excitation is studied. The simulation results indicate that linear behavior is preserved beyond the first impact, and some mesh distortion is observed following a stronger second impact. During the impact, the displacement of the contacting surface nodes remains constant, and the velocities are reduced to zero. An identification of impacting nodes is possible from the dynamic pressures induced in surface elements.

  16. Global Cooling: Policies to Cool the World and Offset Global Warming from CO2 Using Reflective Roofs and Pavements

    SciTech Connect

    Akbari, Hashem; Levinson, Ronnen; Rosenfeld, Arthur; Elliot, Matthew

    2009-08-28

    Increasing the solar reflectance of the urban surface reduce its solar heat gain, lowers its temperatures, and decreases its outflow of thermal infrared radiation into the atmosphere. This process of 'negative radiative forcing' can help counter the effects of global warming. In addition, cool roofs reduce cooling-energy use in air conditioned buildings and increase comfort in unconditioned buildings; and cool roofs and cool pavements mitigate summer urban heat islands, improving outdoor air quality and comfort. Installing cool roofs and cool pavements in cities worldwide is a compelling win-win-win activity that can be undertaken immediately, outside of international negotiations to cap CO{sub 2} emissions. We propose an international campaign to use solar reflective materials when roofs and pavements are built or resurfaced in temperate and tropical regions.

  17. The Analysis of Dynamic Thermal Performance of Insulated Wall and Building Cooling Energy Consumption in Guangzhou

    E-print Network

    Zhao, L.; Li, X.; Li, L.; Gao, Y.

    2006-01-01

    conditioning mainly with the increase of the live level. This study investigates the influence of the thermal dynamic performance on the yearly cooling load and yearly maximum cooling demand in typical residential flats by employing KVALUE and De...

  18. Bio-Climatic Analysis and Thermal Performance of Upper Egypt A Case Study Kharga Region 

    E-print Network

    Khalil, M. H.

    2012-01-01

    thermal performance, which is a function of building form, orientation, location, and materials used and produce comfortable environmental conditions without increasing of energy consumed. This can be valid in three stage, the first one by using the bio...

  19. Effects of Courtyard on Thermal Performance of Commercial Buildings in Hot-Dry Climate, Ahmedabad, India 

    E-print Network

    Kumar, R,

    2009-01-01

    of the simulation exercise has been established on the available weather data. The result would be the analysis of energy performance of different building models. Keywords: Courtyards, Building Configuration, Energy Consumption, Thermal Simulation, Computer...

  20. The thermal performance of fixed and variable selective transmitters in commercial architecture

    E-print Network

    Bartovics, William A

    1984-01-01

    A parametric model is developed for use in evaluating the relative thermal and lighting performance of a variety of existing and proposed types of commercial glazing materials. The glazing materials considered are divided ...

  1. Thermal mass performance in residential construction : an energy analysis using a cube model

    E-print Network

    Ledwith, Alison C. (Alison Catherine)

    2012-01-01

    Given the pervasiveness of energy efficiency concerns in the built environment, this research aims to answer key questions regarding the performance of thermal mass construction. The work presents the Cube Model, a simplified ...

  2. Short time scale thermal mechanical shock wave propagation in high performance microelectronic packaging configuration 

    E-print Network

    Nagaraj, Mahavir

    2004-11-15

    The generalized theory of thermoelasticity was employed to characterize the coupled thermal and mechanical wave propagation in high performance microelectronic packages. Application of a Gaussian heat source of spectral profile similar to high...

  3. Thermal performance of a proposed evacuated multi-layer insulation system for the National Aerospace Plane

    NASA Astrophysics Data System (ADS)

    Dube, W. P.; Slifka, A. J.; Jeffs, R. L.

    The National Aerospace Plane (NASP) will require thermal insulation systems which are consistent with cryogenic fluids, high thermal loads, and design restrictions such as weight and volume. Test sections of the proposed system have been constructed and evaluated. In this paper we discuss the components of the insulation system, the application of the insulation system to the NASP liquid hydrogen fuel tank system, and thermal conductivity measurements performed on test sections of the system. Both steady-state and transient thermal measurements are presented.

  4. On-Orbit Thermal Performance and Model Correlation of the Fast Auroral Snapshot Explorer

    NASA Technical Reports Server (NTRS)

    Parrish, Keith

    1999-01-01

    The Fast Auroral SnapshoT explorer (FAST) spacecraft, the second of NASA's Small Explorer (SMEX) series of scientific satellites, was launched on August 21, 1996 by a Pegasus XL launch vehicle. Due to slightly higher than expected temperatures during early orbit operations, an extensive thermal model correlation effort was undertaken to understand and characterize FAST's thermal performance in order to properly orient the spacecraft's attitude during its mission. FAST's thermal design and the on-orbit thermal model correlation and resolution are described. Finally, the correlated model's predictions are compared with nine months of flight data.

  5. Green Roof Stormwater Retention: Effects of Roof Surface, Slope, and Media Depth

    Microsoft Academic Search

    Nicholaus D. VanWoert; D. Bradley Rowe; Jeffrey A. Andresen; Clayton L. Rugh; R. Thomas Fernandez; Lan Xiao

    2005-01-01

    ABSTRACT,thussavingonenergyconsumption(Niachouetal.,2001; Wong et al., 2003); increase thelife span of a typical roof Urban areas generate considerably more stormwater runoff than byprotectingtheroofcomponentsfromdamagingultra- natural areas of the same size due to a greater percentage of impervi- ous surfaces that impede water infiltration. Roof surfacesother impervious surfaces can exacerbate flooding, in- media clearly reduced the total quantity of runoff. For both studies, crease

  6. Process of making cryogenically cooled high thermal performance crystal optics

    DOEpatents

    Kuzay, Tuncer M. (Naperville, IL)

    1992-01-01

    A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N.sub.2 is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.

  7. Thermal effects on human performance in office environment measured by integrating task speed and accuracy.

    PubMed

    Lan, Li; Wargocki, Pawel; Lian, Zhiwei

    2014-05-01

    We have proposed a method in which the speed and accuracy can be integrated into one metric of human performance. This was achieved by designing a performance task in which the subjects receive feedback on their performance by informing them whether they have committed errors, and if did, they can only proceed when the errors are corrected. Traditionally, the tasks are presented without giving this feedback and thus the speed and accuracy are treated separately. The method was examined in a subjective experiment with thermal environment as the prototypical example. During exposure in an office, 12 subjects performed tasks under two thermal conditions (neutral & warm) repeatedly. The tasks were presented with and without feedback on errors committed, as outlined above. The results indicate that there was a greater decrease in task performance due to thermal discomfort when feedback was given, compared to the performance of tasks presented without feedback. PMID:23871091

  8. Differential thermal performance curves in response to different habitats in the parasitoid Venturia canescens

    NASA Astrophysics Data System (ADS)

    Foray, Vincent; Gibert, Patricia; Desouhant, Emmanuel

    2011-08-01

    Environmental variability is expected to be important in shaping performance curves, reaction norms of phenotypic traits related to fitness. Models predict that the breadth of performance curves should increase with environmental variability at the expense of maximal performance. In this study, we compared the thermal performance curves of two sympatric populations of the parasitoid Venturia canescens that were observed under contrasting thermal regimes in their respective preferred habitats and differing in their modes of reproduction. Our results confirm the large effect of developmental temperature on phenotypic traits of insects and demonstrate that thelytokous and arrhenotokous wasps respond differently to temperature during development, in agreement with model predictions. For traits related to fecundity, thelytokous parasitoids, which usually occur in stable thermal conditions, exhibit specialist performance curves, maximising their reproductive success under a restricted range of temperature. In contrast, arrhenotokous parasitoids, which occur in variable climates, exhibit generalist performance curves, in keeping with the hypothesis "jack of all temperatures, master of none".

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

    PubMed

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

    2005-01-01

    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

  10. Performance Testing of Thermal Cutting Systems for Sweet Pepper Harvesting Robot in Greenhouse Horticulture

    NASA Astrophysics Data System (ADS)

    Bachche, Shivaji; Oka, Koichi

    2013-03-01

    This paper proposes design of end-effector and prototype of thermal cutting system for harvesting sweet peppers. The design consists of two parallel gripper bars mounted on a frame connected by specially designed notch plate and operated by servo motor. Based on voltage and current, two different types of thermal cutting system prototypes; electric arc and temperature arc respectively were developed and tested for performance. In electric arc, a special electric device was developed to obtain high voltage to perform cutting operation. At higher voltage, electrodes generate thermal arc which helps to cut stem of sweet pepper. In temperature arc, nichrome wire was mounted between two electrodes and current was provided directly to electrodes which results in generation of high temperature arc between two electrodes that help to perform cutting operation. In both prototypes, diameters of basic elements were varied and the effect of this variation on cutting operation was investigated. The temperature arc thermal system was found significantly suitable for cutting operation than electric arc thermal system. In temperature arc thermal cutting system, 0.5 mm nichrome wire shows significant results by accomplishing harvesting operation in 1.5 seconds. Also, thermal cutting system found suitable to increase shelf life of fruits by avoiding virus and fungal transformation during cutting process and sealing the fruit stem. The harvested sweet peppers by thermal cutting system can be preserved at normal room temperature for more than 15 days without any contamination.

  11. The Effect of Cooling Methods on the Performance of Solid Nitrogen Thermal Batteries

    NASA Astrophysics Data System (ADS)

    Jarvis, A. L. L.; Swann, B. M.; Archer, J. C.

    A test cryostat has been constructed to study thermal batteries. Solid nitrogen, used as a thermal battery, may be used as a temporary portable cooling system or a heat absorber for a superconducting fault current limiter system. The nitrogen was solidified via different cooling profiles. The performance of thermal batteries was determined by subjecting them to transient thermal events. It was found that slowly formed solid nitrogen performed best, by returning to operating temperature faster. The thermal contact degradation due to 'dry-out' was identified as a significant problem after a number of successive pulses when using rapidly formed solid nitrogen, yet did not present itself in slowly formed solid nitrogen, within experimental range.

  12. Effects of aerodynamic heating and TPS thermal performance uncertainties on the Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Goodrich, W. D.; Derry, S. M.; Maraia, R. J.

    1980-01-01

    A procedure for estimating uncertainties in the aerodynamic-heating and thermal protection system (TPS) thermal-performance methodologies developed for the Shuttle Orbiter is presented. This procedure is used in predicting uncertainty bands around expected or nominal TPS thermal responses for the Orbiter during entry. Individual flowfield and TPS parameters that make major contributions to these uncertainty bands are identified and, by statistical considerations, combined in a manner suitable for making engineering estimates of the TPS thermal confidence intervals and temperature margins relative to design limits. Thus, for a fixed TPS design, entry trajectories for future Orbiter missions can be shaped subject to both the thermal-margin and confidence-interval requirements. This procedure is illustrated by assessing the thermal margins offered by selected areas of the existing Orbiter TPS design for an entry trajectory typifying early flight test missions.

  13. Geologic structures in coal mine roof. Rept of investigations/1982

    SciTech Connect

    Moebs, N.N.; Ellenberger, J.L.

    1982-02-01

    Studies by the Bureau of Mines have identified geologic structures in mine roof rock that contribute to many roof falls in Appalachian coal mines. These structures, including paleochannels, scours, pinchouts, slickensides, clay veins, crevasse splays, and joints, can often be identified during, and sometimes before, mine development. Mine projections can be revised to reduce the adverse effects of discontinuities in roof structure; large roof areas of laminated sandstone or incompetent strata generally can be delineated or inferred from exploratory drill hole data, and the need for supplementary support can be anticipated. Accurate descriptions of roof geology also provide some indication of optimum length and type of roof bolts that should be installed.

  14. Utility impact and thermal performance of the Franta residence

    SciTech Connect

    Franta, G. (Solar Energy Research Inst., Golden CO); Connolly, M.; Winn, B

    1981-01-01

    The Franta residence uses a unique combination of passive and hybrid solar applications to reduce total energy use and peak energy demands for heating, cooling, and lighting. The residence, occupied by a family of three, is integrated into the neighborhood of a Denver suburb. The design program objective called for the residence to use less than 800 kWh per year to heat and cool the all-electric residence. This goal has been more than achieved by the residence using only 153 kWh of heating and cooling electrical energy for the first half year of operation (November 1980 to April 1981). Further objectives were to produce an aesthetically pleasing design, to maintain thermal comfort levels, and to have a minimal impact on the lifestyle of the occupants.

  15. A Parametric Analysis of the Thermal Performance of Concrete Floor Slabs in Cold Climates

    NASA Astrophysics Data System (ADS)

    Di Placido, Adam Michael

    The inherent thermal mass within the structural components of concrete buildings can have significant influence on energy efficiency in regard to heating and cooling in cold climates. Understanding the influence of building parameters on the passive storage of heat within heavy building materials is thus imperative when informing design decisions regarding energy efficiency. A parametric analysis was performed using energy modeling to characterize the thermal performance of concrete floor slabs in Toronto, Canada. Results showed that the most important factor influencing the relative performance of floor mass is the solar radiation transmitted through exterior glazing. The distribution of internal thermal mass and the density of internal gains were also found to be influential factors. Results were used to inform general concrete slab design guidelines for fully exploiting the thermal mass benefit by recommending minimum slab thicknesses. It is expected that in many cases, structural slab requirements will fulfill these recommendations.

  16. Thermal Performance Comparison of Glass Microsphere and Perlite Insulation Systems for Liquid Hydrogen Storage Tanks

    NASA Astrophysics Data System (ADS)

    Sass, J. P.; Fesmire, J. E.; Nagy, Z. F.; Sojourner, S. J.; Morris, D. L.; Augustynowicz, S. D.

    2008-03-01

    A technology demonstration test project was conducted by the Cryogenics Test Laboratory at the Kennedy Space Center (KSC) to provide comparative thermal performance data for glass microspheres, referred to as bubbles, and perlite insulation for liquid hydrogen tank applications. Two identical 1/15th scale versions of the 3,200,000 liter spherical liquid hydrogen tanks at Launch Complex 39 at KSC were custom designed and built to serve as test articles for this test project. Evaporative (boil-off) calorimeter test protocols, including liquid nitrogen and liquid hydrogen, were established to provide tank test conditions characteristic of the large storage tanks that support the Space Shuttle launch operations. This paper provides comparative thermal performance test results for bubbles and perlite for a wide range of conditions. Thermal performance as a function of cryogenic commodity (nitrogen and hydrogen), vacuum pressure, insulation fill level, tank liquid level, and thermal cycles will be presented.

  17. Prevention of residential roof fires by use of a class "A" fire rated roof system.

    PubMed

    Edlich, Richard F; Winters, Kathryne L; Long, William B; Britt, L D

    2004-01-01

    Because residential roof fires remain a life-threatening danger to residential homeowners in the United States, we describe in detail a national fire prevention program for reducing residential roof fires by use of an Underwriters Laboratories Inc. (UL) and National Fire Protection Association Class A fire rated roof system. This Class A system should comply with the test requirements for fire resistance of roof coverings, as outlined in UL 790 or in ASTM International (ASTM) E-108. Both the Asphalt Roofing Manufacturer's Association (ARMA) and the National Roofing Contractors Association (NRCA) have set up guidelines for selecting a new roof for the homeowner. Class A, fiber-glass-based asphalt roofing shingles represent an overwhelming share of the United States residential roofing market, and, as such, the Class A rated roofing system remains an excellent alternative to wood shingles and shakes. Fortunately, the Class A fire rating is available for certain wood shingle products that incorporate a factory-applied, fire resistant treatment. However, in this circumstance, wood products labeled as Class B shakes or shingles must be installed over spaced or solid sheathing that have been covered either with one layer of 1/4 in. (6.4 mm) thick noncombustible roof board, or with one layer of minimum 72-lb. fiber-glass-based mineral surfaced cap sheet, or with another specialty roofing sheet to obtain the Class A fire rating. Clay, tile, slate, and metal have been assigned Class A fire ratings in the codes (but often without testing). These alternative roofing materials are often considerably more expensive. Proper application, ventilation, and insulation of roofing systems are required to prevent heat and moisture buildup in the attic, which can damage the roofing system, making it more susceptible to water leakage as well as ignition in the event of a fire. The NRCA has devised excellent recommendations for the homeowner to prequalify the contractor. In addition, a warranty for any new roofing material is important for the homeowner to ensure that the roofing can be repaired by the contractor or manufacturer during the specified warranty period, in case of contractor error or a manufacturing defect. In addition, the homeowner should ensure that the warranty is transferable to any future owner of the home to allow the buyer to have the same warranty benefits as the original owner. The State of California has mandated strict roofing requirements to prevent residential fires. In the absence of this legislation in other states, the homeowner must follow the guidelines outlined in this collective review to ensure that a roofing system with Class A fire protection is installed. Other fire safety precautions that should also be considered mandatory are to include smoke alarms, escape plans, and retrofit fire sprinklers. PMID:15099189

  18. Differential thermal performance curves in response to different habitats in the parasitoid Venturia canescens

    Microsoft Academic Search

    Vincent Foray; Patricia Gibert; Emmanuel Desouhant

    2011-01-01

    Environmental variability is expected to be important in shaping performance curves, reaction norms of phenotypic traits related\\u000a to fitness. Models predict that the breadth of performance curves should increase with environmental variability at the expense\\u000a of maximal performance. In this study, we compared the thermal performance curves of two sympatric populations of the parasitoid\\u000a Venturia canescens that were observed under

  19. http://www.cse.wustl.edu/~jain/cse567-06/ftp/thermal/index.html 1 of 18 A Performance Model for a Thermally Adaptive

    E-print Network

    Jain, Raj

    Hardware 3.2 Thermally Adaptive Frequency Control 3.2.1 Overview 3.2.2 Implementation Details 4 environments (e.g. space borne and military systems). High powered thermally aggressive applications that dohttp://www.cse.wustl.edu/~jain/cse567-06/ftp/thermal/index.html 1 of 18 A Performance Model

  20. Evaluation of thermal performance for air-insulated busbar trunking system by coupled magneto-fluid-thermal fields

    Microsoft Academic Search

    Wu Anbo; Chen Degui; Wang Jianhua; Cai Bin; Geng Yingsan

    2002-01-01

    The temperature rise of a busbar trunking system is a vital factor that affects its performance. In this paper, a two-dimensional coupled magneto-fluid-thermal finite element analysis model is presented for the evaluation of electrical heating and natural convection for busbar trunking systems. The power-frequency harmonic magnetic field, eddy currents and power loss of an air-insulated busbar trunking system are calculated

  1. Planck early results. II. The thermal performance of Planck

    Microsoft Academic Search

    P. A. R. Ade; N. Aghanim; M. Arnaud; M. Ashdown; J. Aumont; C. Baccigalupi; M. Baker; A. Balbi; A. J. Banday; R. B. Barreiro; E. Battaner; K. Benabed; A. Benoît; J.-P. Bernard; M. Bersanelli; P. Bhandari; R. Bhatia; J. J. Bock; A. Bonaldi; J. R. Bond; J. Borders; J. Borrill; B. Bowman; T. Bradshaw; E. Bréelle; M. Bucher; C. Burigana; R. C. Butler; P. Cabella; C. M. Cantalupo; B. Cappellini; J.-F. Cardoso; A. Catalano; L. Cayón; A. Challinor; A. Chamballu; J. P. Chambelland; J. Charra; M. Charra; L.-Y. Chiang; C. Chiang; P. R. Christensen; D. L. Clements; B. Collaudin; S. Colombi; F. Couchot; A. Coulais; B. P. Crill; M. Crook; F. Cuttaia; C. Damasio; L. Danese; R. D. Davies; R. J. Davis; P. de Bernardis; G. de Gasperis; A. de Rosa; J. Delabrouille; J.-M. Delouis; F.-X. Désert; K. Dolag; S. Donzelli; O. Doré; U. Dörl; M. Douspis; X. Dupac; G. Efstathiou; T. A. Enßlin; H. K. Eriksen; C. Filliard; F. Finelli; S. Foley; O. Forni; P. Fosalba; J.-J. Fourmond; M. Frailis; E. Franceschi; S. Galeotta; K. Ganga; E. Gavila; M. Giard; G. Giardino; Y. Giraud-Héraud; J. González-Nuevo; K. M. Górski; S. Gratton; A. Gregorio; A. Gruppuso; G. Guyot; D. Harrison; G. Helou; S. Henrot-Versillé; C. Hernández-Monteagudo; D. Herranz; S. R. Hildebrandt; E. Hivon; M. Hobson; A. Hornstrup; W. Hovest; R. J. Hoyland; K. M. Huffenberger; U. Israelsson; A. H. Jaffe; W. C. Jones; M. Juvela; E. Keihänen; R. Keskitalo; T. S. Kisner; R. Kneissl; L. Knox; H. Kurki-Suonio; G. Lagache; J.-M. Lamarre; P. Lami; A. Lasenby; R. J. Laureijs; A. Lavabre; C. R. Lawrence; S. Leach; R. Lee; R. Leonardi; C. Leroy; P. B. Lilje; M. López-Caniego; P. M. Lubin; J. F. Macías-Pérez; T. Maciaszek; C. J. MacTavish; B. Maffei; D. Maino; N. Mandolesi; R. Mann; M. Maris; E. Martínez-González; S. Masi; S. Matarrese; F. Matthai; P. Mazzotta; P. McGehee; P. R. Meinhold; A. Melchiorri; F. Melot; L. Mendes; A. Mennella; M.-A. Miville-Deschênes; A. Moneti; L. Montier; J. Mora; G. Morgante; N. Morisset; D. Mortlock; D. Munshi; A. Murphy; P. Naselsky; A. Nash; P. Natoli; C. B. Netterfield; D. Novikov; I. Novikov; I. J. O'Dwyer; S. Osborne; F. Pajot; F. Pasian; G. Patanchon; D. Pearson; O. Perdereau; L. Perotto; F. Perrotta; F. Piacentini; M. Piat; S. Plaszczynski; P. Platania; E. Pointecouteau; G. Polenta; N. Ponthieu; T. Poutanen; G. Prézeau; M. Prina; S. Prunet; J.-L. Puget; J. P. Rachen; R. Rebolo; M. Reinecke; C. Renault; S. Ricciardi; T. Riller; I. Ristorcelli; G. Rocha; C. Rosset; J. A. Rubiño-Martín; B. Rusholme; M. Sandri; D. Santos; G. Savini; B. M. Schaefer; D. Scott; M. D. Seiffert; P. Shellard; G. F. Smoot; J.-L. Starck; P. Stassi; F. Stivoli; V. Stolyarov; R. Stompor; R. Sudiwala; J.-F. Sygnet; J. A. Tauber; L. Terenzi; L. Toffolatti; M. Tomasi; J.-P. Torre; M. Tristram; J. Tuovinen; L. Valenziano; L. Vibert; P. Vielva; F. Villa; N. Vittorio; A. Wilkinson; B. D. Wandelt; C. Watson; S. D. M. White; P. Wilson; D. Yvon; A. Zacchei; B. Zhang; A. Zonca

    2011-01-01

    The performance of the Planck instruments in space is enabled by their low operating temperatures, 20 K for LFI and 0.1 K for HFI, achieved through a combination of passive radiative cooling and three active mechanical coolers. The scientific requirement for very broad frequency coverage led to two detector technologies with widely different temperature and cooling needs. Active coolers could

  2. Performance evaluation of solar thermal electric generation systems

    Microsoft Academic Search

    S. D Odeh; M Behnia; G. L Morrison

    2003-01-01

    A unified model of a solar electric generation system (SEGS) is developed using a thermo–hydrodynamic model of a direct steam collector combined with a model of a traditional steam power house. The model is used to study the performance of different collector field and power house arrangements under Australian conditions. To find the effect of collector inclination on the SEGS

  3. Performance assessment of low pressure nuclear thermal propulsion

    NASA Technical Reports Server (NTRS)

    Gerrish, H. P., Jr.; Doughty, G. E.

    1993-01-01

    A low pressure nuclear thermal propulsion (LPNTP) system, which takes advantage of hydrogen dissociation/recombination, was proposed as a means of increasing engine specific impulse (Isp). The effect of hydrogen dissociation/recombination on LPNTP Isp is examined. A two-dimensional computer model was used to show that the optimum chamber pressure is approximately 100 psia (at a chamber temperature of 3,000 K), with an Isp approximately 15 s higher than at 1,000 psia. At high chamber temperatures and low chamber pressures, the increase in Isp is due to both lower average molecular weights caused by dissociation and added kinetic energy from monatomic hydrogen recombination. Monatomic hydrogen recombination increases the Isp more then hydrogen dissociation. Variations in the mole fraction of monatomic hydrogen are similar to variations in static pressure along the axial nozzle position. Most recombination occurs close to the nozzle throat. Practical variations in nozzle geometry have minimal impact on recombination. Other models which can simulate a wider range of nozzle designs should be used in the future. The uncertainty of the hydrogen kinetic reaction rates at high temperatures (approximately 3,000 K) affects the accuracy of the analysis and should be verified with simple bench tests.

  4. Thermal Performance of the Mars Science Laboratory Rover During Mars Surface Operations

    NASA Technical Reports Server (NTRS)

    Novak, Keith S.; Kempenaar, Joshua E.; Liu, Yuanming; Bhandari, Pradeep; Lee, Chern-Jiin

    2013-01-01

    On November 26, 2011, NASA launched a large (900 kg) rover as part of the Mars Science Laboratory (MSL) mission to Mars. Eight months later, on August 5, 2012, the MSL rover (Curiosity) successfully touched down on the surface of Mars. As of the writing of this paper, the rover had completed over 200 Sols of Mars surface operations in the Gale Crater landing site (4.5 degrees South latitude). This paper describes the thermal performance of the MSL Rover during the early part of its two Earth-0.year (670 Sols) prime surface mission. Curiosity landed in Gale Crater during early Spring (Solar longitude=151) in the Southern Hemisphere of Mars. This paper discusses the thermal performance of the rover from landing day (Sol 0) through Summer Solstice (Sol 197) and out to Sol 204. The rover surface thermal design performance was very close to pre-landing predictions. The very successful thermal design allowed a high level of operational power dissipation immediately after landing without overheating and required a minimal amount of survival heating. Early morning operations of cameras and actuators were aided by successful heating activities. MSL rover surface operations thermal experiences are discussed in this paper. Conclusions about the rover surface operations thermal performance are also presented.

  5. Three-Dimensional Numerical Evaluation of Thermal Performance of Uninsulated Wall Assemblies: Preprint

    SciTech Connect

    Ridouane, E. H.; Bianchi, M.

    2011-11-01

    This study describes a detailed three-dimensional computational fluid dynamics modeling to evaluate the thermal performance of uninsulated wall assemblies accounting for conduction through framing, convection, and radiation. The model allows for material properties variations with temperature. Parameters that were varied in the study include ambient outdoor temperature and cavity surface emissivity. Understanding the thermal performance of uninsulated wall cavities is essential for accurate prediction of energy use in residential buildings. The results can serve as input for building energy simulation tools for modeling the temperature dependent energy performance of homes with uninsulated walls.

  6. Performance of abutment–backfill system under thermal variations in integral bridges built on clay

    Microsoft Academic Search

    Murat Dicleli; Suhail M. Albhaisi

    2004-01-01

    In this paper, performance of the abutment–backfill system under thermal variations is studied. For this purpose, a structural model of a typical integral bridge is built considering the nonlinear behavior of the piles and soil–bridge interaction effects. Static pushover analyses of the bridge are conducted to study the effect of various geometric, structural and geotechnical parameters on the performance of

  7. Prediction of thermal-hydraulic performance of gas-cooled fast breeder reactors. Final report

    Microsoft Academic Search

    C. Jr. Gazley; G. H. Harpole; L. S. Yao; W. H. Krase; J. Catton; J. Grzesik; W. Matyskiela

    1977-01-01

    The report describes work performed under a project to examine the thermal-hydraulic performance of gas-cooled fast breeder reactors (GCFRs). Existing GCFR designs are briefly described with emphasis on the core cooling and associated systems. Factors affecting the convective heat transfer and pressure drop in the core are examined, particularly the effects of surface roughness on the enhancement of heat transfer,

  8. Thermal performance of cold-formed thin-walled steel panel systems in fire

    Microsoft Academic Search

    M. Feng; Yong Wang; J. M. Davies

    2003-01-01

    The thermal performance of cold-formed thin-walled steel panel systems in fire was discussed. The performance of the steel sections was influenced by the presence of protective layers made from gypsum boards. They quickly dissipated heat to the surroundings and led to rapid temperature increase. The temperature of the steel section of a steel stud panel system was found to depend

  9. SOLSTEP - A computer model for predicting the thermodynamic and economic performance of solar thermal power plants

    Microsoft Academic Search

    S. P. Bird

    1979-01-01

    A thermodynamic and economic performance analysis code, SOLSTEP, was developed to facilitate the evaluation of solar thermal power plant designs. The code conducts a time step simulation of the plant thermodynamic performance using actual recorded meteorological and insolation data. Each analysis case provides capacity factor and levelized energy cost results for several plant configurations using various combinations of collector field

  10. Theory vs. Practice in Direct Evaporative Roof Spray Cooling 

    E-print Network

    Smith, J. L.; Smith, J. C.

    1985-01-01

    This paper will examine in depth the development of roof spray cooling in this country and elsewhere, the theory and practice of roof cooling, and the limits of system application. While this relatively simple method of air conditioning has been...

  11. Eastern portal, looking W. Note hipped roof covered with wood ...

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

    Eastern portal, looking W. Note hipped roof covered with wood shingles, added in 1993. The hipped roof is unique in U.S. covered bridges. - Doe River Bridge, Spanning Doe River, Third Avenue, Elizabethton, Carter County, TN

  12. 13. INTERIOR OF TAN 629 HANGAR, TAKEN ON LOW ROOF ...

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

    13. INTERIOR OF TAN 629 HANGAR, TAKEN ON LOW ROOF ON WEST SIDE, FACING SOUTH. SHOWS SMC ROOF UTILITY PAD. - Idaho National Engineering Laboratory, Test Area North, Hangar No. 629, Scoville, Butte County, ID

  13. Evaluation of a Direct Evaporative Roof-Spray Cooling System

    E-print Network

    Carrasco, A.; Pittard, R.; Kondepudi, S. N.; Somasundaram, S.

    1987-01-01

    EVALUATION OF A DIRECT EVAPORATIVE ROOF-SPRAY COOLING SYSTEM Carrasco, A., Pittard, R., Kondepudi, S. N., and Somasundaram, S. Mechanical Engineering Department, Texas A&M University, College Station. ABSTRACT Roof-Spray cooling systems...

  14. 3. View from roof of eastern segment of Roundhouse looking ...

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

    3. View from roof of eastern segment of Roundhouse looking at roof and clerestory of western segment. - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Roundhouse, Site Bounded by West Broad, Jones, West Boundary & Hull, Savannah, Chatham County, GA

  15. Theory vs. Practice in Direct Evaporative Roof Spray Cooling

    E-print Network

    Smith, J. L.; Smith, J. C.

    1985-01-01

    This paper will examine in depth the development of roof spray cooling in this country and elsewhere, the theory and practice of roof cooling, and the limits of system application. While this relatively simple method of air conditioning has been...

  16. 46. OCTAGONAL & WEST TOWERS FROM SOUTH TOWER ROOF, LOOKING ...

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

    46. OCTAGONAL & WEST TOWERS FROM SOUTH TOWER ROOF, LOOKING NORTHWEST, WITH WEST WING ROOF - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

  17. 42. SOUTHEAST TOWER & EAST WING ROOF FROM SOUTH TOWER ...

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

    42. SOUTHEAST TOWER & EAST WING ROOF FROM SOUTH TOWER ROOF, LOOKING EAST BY NORTHEAST - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

  18. Attic or Roof? An Evaluation of Two Advanced Weatherization Packages

    SciTech Connect

    Neuhauser, K.

    2012-06-01

    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.

  19. THERMAL CONDUCTIVITY PERFORMANCE MODELING AND CHARACTERIZATION OF A NOVEL ANISOTROPIC CONDUCTIVE ADHESIVE USED IN LEAD-FREE ELECTRONICS

    E-print Network

    Kandlikar, Satish

    1 THERMAL CONDUCTIVITY PERFORMANCE MODELING AND CHARACTERIZATION OF A NOVEL ANISOTROPIC CONDUCTIVE will present the findings of the thermal conductivity performance tests using the novel ACA and its, etc. The columns that act as electrical conduction paths also contribute towards the thermal

  20. The wind resistance of asphalt roofing shingles

    NASA Astrophysics Data System (ADS)

    Dixon, Craig Robert

    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.

  1. Analysis of Wind Forces on Roof-Top Solar Panel

    NASA Astrophysics Data System (ADS)

    Panta, Yogendra; Kudav, Ganesh

    2011-03-01

    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. Acknowledgments to Northern States Metal Inc., OH (GK & YP) and School of Graduate Studies of YSU for RP & URC 2009-2010 (YP).

  2. Mechanical and thermal performance of C/SiC composites for SPICA mirror

    NASA Astrophysics Data System (ADS)

    Ozaki, Tsuyoshi; Kume, Masami; Oshima, Takeharu; Nakagawa, Takao; Matsumoto, Toshio; Kaneda, Hidehiro; Murakami, Hiroshi; Kataza, Koichi; Enya, Keigo; Yui, Yukari; Onaka, Takashi; Krodel, Matthias R.

    2004-09-01

    One of the key technologies for next generation space telescope with a large-scale reflector is a material having high specific strength, high specific stiffness, low coefficient of thermal expansion and high coefficient of thermal conductivity. Several candidates such as fused silica, beryllium, silicon carbide and carbon fiber reinforced composites have been evaluated. Pitch-based carbon fiber reinforced SiC composites were developed for the SPICA space telescope mirror to comply with such requirements. Mechanical performance such as bending stiffness, bending strength and fracture toughness was significantly improved. Evaluation procedures of thermal expansion and thermal conductivity behavior at cryogenic temperatures (as low as 4.5K) were established and excellent performance for the SPICA mirror was demonstrated.

  3. Mechanical and thermal performance of C/SiC composites for SPICA mirror

    NASA Astrophysics Data System (ADS)

    Ozaki, T.; Kume, M.; Oshima, T.; Nakagawa, T.; Matsumoto, T.; Kaneda, H.; Murakami, H.; Kataza, K.; Enya, K.; Yui, Y.; Onaka, T.; Kroedel, M.

    2005-08-01

    One of the key technologies for next generation space telescope with a large-scale reflector is a material having high specific strength, high specific stiffness, low coefficient of thermal expansion and high coefficient of thermal conductivity. Several candidates such as fused silica, beryllium, silicon carbide and carbon fiber reinforced composites have been evaluated. Pitch-based carbon fiber reinforced SiC composites were developed for the SPICA space telescope mirror to comply with such requirements. Mechanical performance such as bending stiffness, bending strength and fracture toughness was significantly improved. Evaluation procedures of thermal expansion and thermal conductivity behavior at cryogenic temperatures (as low as 4.5K) were established and excellent performance for the SPICA mirror was demonstrated.

  4. Estimation and optimization of thermal performance of evacuated tube solar collector system

    NASA Astrophysics Data System (ADS)

    Dikmen, Erkan; Ayaz, Mahir; Ezen, H. Hüseyin; Küçüksille, Ecir U.; ?ahin, Arzu ?encan

    2014-05-01

    In this study, artificial neural networks (ANNs) and adaptive neuro-fuzzy (ANFIS) in order to predict the thermal performance of evacuated tube solar collector system have been used. The experimental data for the training and testing of the networks were used. The results of ANN are compared with ANFIS in which the same data sets are used. The R2-value for the thermal performance values of collector is 0.811914 which can be considered as satisfactory. The results obtained when unknown data were presented to the networks are satisfactory and indicate that the proposed method can successfully be used for the prediction of the thermal performance of evacuated tube solar collectors. In addition, new formulations obtained from ANN are presented for the calculation of the thermal performance. The advantages of this approaches compared to the conventional methods are speed, simplicity, and the capacity of the network to learn from examples. In addition, genetic algorithm (GA) was used to maximize the thermal performance of the system. The optimum working conditions of the system were determined by the GA.

  5. Thermal Performance of Sprayed Polyurethane Foam Insulation with Alternative Blowing Agents

    Microsoft Academic Search

    M. K. Kumaran; M. T. Bomberg

    1990-01-01

    A test methodology that uses thermal resistance-time curves deter mined on thin shces of the foam and the scaling technique to relate aging time to the specimen thickness, was applied to evaluate long-term thermal performance of six polyurethane foams manufactured with the same polymer but different blowing agents. The blowing agents employed were: CFC-11 with 0, 0 5, 1 0

  6. Performance characteristics of a thermal energy storage module - A transient PCM/forced convection conjugate analysis

    NASA Technical Reports Server (NTRS)

    Cao, Y.; Faghri, A.

    1991-01-01

    The performance of a thermal energy storage module is simulated numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid with low Prandtl numbers are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. The numerical results show that module geometry is crucial to the design of a space-based thermal energy storage system.

  7. Calorimetric thermal-vacuum performance characterization of the BAe 80 K space cryocooler

    Microsoft Academic Search

    V. Y. Kotsubo; D. L. Johnson; R. G. Ross Jr.

    1992-01-01

    A comprehensive characterization program is underway at JPL to generate test data on long-life, miniature Stirling-cycle cryocoolers for space application. The key focus of this paper is on the thermal performance of the British Aerospace (BAe) 80 K split-Stirling-cycle cryocooler as measured in a unique calorimetric thermal-vacuum test chamber that accurately simulates the heat-transfer interfaces of space. Two separate cooling

  8. A finite element model for the fire-performance of GRP panels including variable thermal properties

    Microsoft Academic Search

    M. R. E. Looyeh; P. Bettess

    1998-01-01

    A finite element study is conducted to determine the thermal response of a widely used glass reinforced plastic panel exposed to fire. This study is performed based on a formulation developed previously by the authors and improved by including the moisture and temperature-dependent thermal properties and a newly developed time-dependent non-linear mixed boundary condition at the unexposed surface of the

  9. Thermal Performance of a Customized Multilayer Insulation (MLI). Design and Fabrication of Test Facility Hardware

    NASA Technical Reports Server (NTRS)

    Leonhard, K. E.

    1975-01-01

    The design, fabrication, and assembly of hardware for testing the performance of a customized multilayer insulation are discussed. System components described include the thermal payload simulator, the modified cryoshroud, and a tank back pressure control device designed to maintain a constant liquid boiling point during the thermal evaluation of the multilayer insulation. The thermal payload simulator will provide a constant temperature surface in the range of 20.5 to 417K (37 to 750R) for the insulated tank to view. The cryoshroud was modified to establish a low temperature black body cavity while limiting liquid hydrogen usage to a minimum feasible rate.

  10. Comparison of theory and experiment for photovoltaic/thermal collector performance

    SciTech Connect

    Hendrie, S.D.

    1980-01-01

    Detailed performance testing of an air and a liquid type combined photovoltaic/thermal (PV/T) collector has been completed with results of accompanying analytical modeling accurately predicting the experimental data. Thermal efficiencies, with concurrent photovoltaic operation at the maximum power point, are computed in accordance with ASHRAE 93-77 specifications and collector-surface heat-transfer coefficients are determined. Analytical modeling of the two collectors from first principals accounts for the non-ideal bonding of photovoltaic cells to the thermal collector components and for the spacing between cells.

  11. Thermal Impact on the Performance of Highly Efficient Multi-stage Depressed Collector for Space TWT

    NASA Astrophysics Data System (ADS)

    Gahlaut, Vishant; Latha, A. Mercy; Alvi, Parvez Ahmad; Ghosh, Sanjay Kumar

    2014-01-01

    In a travelling wave tube, much of the waste power is dumped into the collector. If the waste heat is not properly managed, it might pose a serious problem causing even failure of tube. In this paper, the optimal choice of thermal management of a highly efficient multistage depressed collector designed for a space TWT has been made based on several criteria. The structural deformations and stresses developed due to thermal impact have been evaluated. The influence of thermal deformations on the collector electrical performance and high voltage withstanding capability has been studied during hot condition.

  12. Thermal performance of gaseous-helium-purged tank-mounted multilayer insulation system during ground-hold and space-hold thermal cycling and exposure to water vapor

    Microsoft Academic Search

    I. E. Sumner

    1978-01-01

    An experimental investigation was conducted to determine (1) the ground-hold and space-hold thermal performance of a multilayer insulation (MLI) system mounted on a spherical, liquid-hydrogen propellant tank and (2) the degradation to the space-hold thermal performance of the insulation system that resulted from both thermal cycling and exposure to moisture. The propellant tank had a diameter of 1.39 meters (4.57ft).

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

    NASA Technical Reports Server (NTRS)

    Glasgow, Shaun; Kittredge, Ken

    2003-01-01

    A thermal interface material is one of the many tools that are often used as part of the thermal control scheme for space-based applications. These materials are placed between, for example, an avionics box and a cold plate, in order to improve the conduction heat transfer so that proper temperatures can be maintained. Historically at Marshall Space Flight Center, CHO-THERM@ 1671 has primarily been used for applications where an interface material was deemed necessary. However, there have been numerous alternatives 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 they do not take into consideration other design issues such as off-gassing, electrical conduction or isolation, etc. This paper details the materials tested, test apparatus, procedures, and results of these tests.

  14. Field-structured, multilayered platelets enable high performance, dielectric thermal composites

    NASA Astrophysics Data System (ADS)

    Martin, James E.; Solis, Kyle J.; Rademacher, David; Raksha, Vladimir

    2012-09-01

    Moldable, thermally conductive polymer composites have broad applications as thermal interface materials and encapsulants. These thermal composites are generally comprised of single-phase particles that are randomly oriented and dispersed. Magnetic platelets have been shown to give exceptionally high thermal conductivities when magnetically aligned along the intended direction of heat flow, but produce composites that are electrically conductive. We have designed precision multilayered platelets that enable the development of high performance thermal composites that are electrically insulating. These platelets consist of a thin Ni core that permits field alignment, Al or Cu coatings that facilitate heat transport, and dielectric layers of MgF2 or SiO2 that ensure that the final composite is electrically insulating. These platelets can be made flat or corrugated, square or irregular, and the thickness of the various layers can be varied over a wide range. Thermal conductivity data for a variety of platelet compositions, layer thicknesses, and geometries demonstrate that these platelets are highly effective at producing composites with thermal conductivities much greater than that of the resin. Simulation data are presented that show that multilayer platelets have surprising dependencies of their efficiency for heat transfer on the relative thermal conductivities of the various layers. In fact, analysis shows that if the thermal conductivity of the particle phase is much greater than that of the resin, then the thermal conductivity of the composite, at fixed number density of particles, is insensitive to the platelet thickness. These electrically insulating composites would be especially useful as thermally conductive encapsulants for electronic devices.

  15. Composite synthetic roofing structure with integral solar collector

    Microsoft Academic Search

    1981-01-01

    A form-molded synthetic foam roofing section or structure is described, having a solar-collecting insert or panel incorporated therein with a relatively broad undersurface and an exposed surface configured to resemble interlocked and overlapping roofing shingles which are united to support a surface such as wood, metal, etc. During the molding process. The roofing structure may be affixed by any conventional

  16. Evolution of cool-roof standards in the United States

    E-print Network

    Akbari, Hashem

    2008-01-01

    the solar reflectance of the shingle roofs to 0.70 fromroof Cool fiberglass asphalt shingles were assigned a solarsolar reflectance required for a steep-sloped roof (0.15) excludes only the hottest of roofing materials, such as granule-surfaced fiberglass asphalt shingles

  17. 40 CFR 63.1043 - Standards-Separator floating roof.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...opening and the closure device. (4) The floating roof may be equipped with one or more emergency roof drains for removal of stormwater. Each emergency roof drain shall be equipped with a slotted membrane fabric cover that covers at least 90 percent of...

  18. 40 CFR 63.1043 - Standards-Separator floating roof.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...opening and the closure device. (4) The floating roof may be equipped with one or more emergency roof drains for removal of stormwater. Each emergency roof drain shall be equipped with a slotted membrane fabric cover that covers at least 90 percent of...

  19. 40 CFR 63.1043 - Standards-Separator floating roof.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...opening and the closure device. (4) The floating roof may be equipped with one or more emergency roof drains for removal of stormwater. Each emergency roof drain shall be equipped with a slotted membrane fabric cover that covers at least 90 percent of...

  20. 40 CFR 63.1043 - Standards-Separator floating roof.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...opening and the closure device. (4) The floating roof may be equipped with one or more emergency roof drains for removal of stormwater. Each emergency roof drain shall be equipped with a slotted membrane fabric cover that covers at least 90 percent of...

  1. 40 CFR 63.1043 - Standards-Separator floating roof.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...opening and the closure device. (4) The floating roof may be equipped with one or more emergency roof drains for removal of stormwater. Each emergency roof drain shall be equipped with a slotted membrane fabric cover that covers at least 90 percent of...

  2. Wind-induced response of a large cantilevered roof

    Microsoft Academic Search

    H. Kawai; R. Yoshie; R. Wei; M. Shimura

    1999-01-01

    The subject of this study is to clarify aerodynamic properties of a large cantilevered roof. We conducted free vibration experiments in order to investigate effects of various parameters such as mass, pitch angle, and damping ratio to wind-induced vibration of the roof. In the experiments, we have found that the roof hardly vibrated at its natural frequency until a certain

  3. Vibration and scattering monitoring of Japanese roofing tile by accelerometer

    Microsoft Academic Search

    Satoru Okamoto

    2011-01-01

    A series of wind tunnel tests were conducted on the vibration and scattering behavior of full-size models of tiles widely used as roofing materials on Japanese wooden dwellings. This study has investigated the nature and source of such movement with the aim of providing better insight into the mechanism. The roofing tiles were set up on a pitched roof in

  4. How much improvement in thermoelectric performance can come from reducing thermal conductivity?

    SciTech Connect

    Gaultois, Michael W., E-mail: mgaultois@mrl.ucsb.edu [Materials Research Laboratory and the Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States); Sparks, Taylor D., E-mail: sparks@eng.utah.edu [Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112 (United States)

    2014-03-17

    Large improvements in the performance of thermoelectric materials have come from designing materials with reduced thermal conductivity. Yet as the thermal conductivity of some materials now approaches their amorphous limit, it is unclear if microstructure engineering can further improve thermoelectric performance in these cases. In this contribution, we use large data sets to examine 300 compositions in 11 families of thermoelectric materials and present a type of plot that quickly reveals the maximum possible zT that can be achieved by reducing the thermal conductivity. This plot allows researchers to quickly distinguish materials where the thermal conductivity has been optimized from those where improvement can be made. Moreover, through these large data sets we examine structure-property relationships to identify methods that decrease thermal conductivity and improve thermoelectric performance. We validate, with the data, that increasing (i) the volume of a unit cell and/or (ii) the number of atoms in the unit cell decreases the thermal conductivity of many classes of materials, without changing the electrical resistivity.

  5. Gender differences in thermal comfort and mental performance at different vertical air temperatures.

    PubMed

    Hashiguchi, Nobuko; Feng, Yue; Tochihara, Yutaka

    2010-05-01

    The purpose of this study was to investigate the effects of a thermal environment where air temperature closer to the ground was lower compared to that above on thermal comfort and mental performance in both sexes. Temperatures at the upper and lower parts of the body were controlled independently using a climatic box placed in a climatic chamber. Sixteen healthy subjects (8 males and 8 females) were exposed to the four conditions with various temperature differences between the upper (25 degrees C) and lower part of the body (16, 19, 22, or 25 degrees C). Skin temperature and subjective votes were measured, and two kinds of task using a computer were performed during exposure. Skin temperature on the back for females was higher than that for males during exposure, and the decrease in thigh skin temperature for females under lower air temperature conditions was significantly larger than that for males. A significant difference in thermal comfort at the beginning of the exposure was indicated between genders, especially in the 16 and 19 degrees C conditions, so females became aware of thermal discomfort before males. Although the score of mental performance based on perceptual speed for females was higher than that for males, there was no significant effect from the different vertical air temperatures. The effect of the unequal thermal environment, where air temperature closer to the ground was lower than above, on skin temperature and thermal discomfort for females was significantly higher compared to males. PMID:19701649

  6. Effect of nanoparticles in nanofluid on thermal performance in a miniature thermosyphon

    Microsoft Academic Search

    Zhen Hua Liu; Xue Fei Yang; Guang Liang Guo

    2007-01-01

    An experiment was performed to investigate the effect of nanoparticles in the nanofluid on the thermal performance in a miniature thermosyphon. The nanofluids consisted of de-ionized water and CuO nanoparticles having an average size of 30 nm. The experimental results show that the water-CuO nanofluids can greatly enhance the boiling heat transfer performance of the evaporator in thermosyphon compared with

  7. Solar energy collector and associated methods adapted for use with overlapped roof shingles on the roof of a building

    Microsoft Academic Search

    1980-01-01

    A method and apparatus are disclosed for collecting solar energy adapted for use with overlapped roof shingles on the roof or side of a building comprising thin flexible metal plates interposed between the overlapped shingles in heat transfer relation therewith such that heat absorbed by the shingles is transferred to the metal plates. The plates extend through the roof via

  8. Solar heater and roof attachment means

    SciTech Connect

    Howe, G.L.; Koutavas, S.G.

    1984-02-21

    A solar heater includes an elongated solar collector having two fixedly connected solar panels of highly heat conductive material supported by a roof clamp on a shingled roof. The bottom edges of each of the solar panels include upturned gutter portions. One form of roof clamp for shingled roofs includes a J-shape shingle clamp member having a clamp bolt extending therethrough, and a solar collector clamp member assembled on the bolt and clamped to the bottom gutter portions of the solar panels. A bottom plate of the J-shape clamp member is slid under a shingle of a first shingle course and under a shingle of a second upper shingle course to carry the bolt into the top of the gap between adjacent shingle portions of the first course and to position a top plate of the shingle clamp member over parts of the shank portions of the first course and over a part of the one shingle of the second course. A clamp nut clamps the collector clamp member and the shingle clamp member firmly to the contacted shingles.

  9. 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...

  10. Roof Shield for Advance and Retreat Mining

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1985-01-01

    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).

  11. Roof Framing. Building Trades. Block V.

    ERIC Educational Resources Information Center

    Texas A and M Univ., College Station. Vocational Instructional Services.

    This curriculum for roof framing provides instructional materials for 11 informational and manipulative lessons. A list of six references precedes the course materials. The instructor's plan for each informational lesson begins by providing this information: subject, aim, required teaching aids, required materials, references, and prerequisite…

  12. Development of Clay Filled Roofing Materials

    Microsoft Academic Search

    Arthur M. Usmani; I. O. Salyer

    1980-01-01

    This paper describes bonding of clay with minor amounts of a phenolic emulsion to produce bricks, roofing tiles or synthetic aggregates, and requires only low temperature baking (100°C to 150°C). The manufacture of conventional bricks is energy intensive whereas our process has low energy requirement.

  13. Plug improves stability of shaly roofs

    SciTech Connect

    Unrug, K.F.; Nandy, S.; Thompson, E. (Univ. of Kentucky, Lexington (United States))

    1991-04-01

    Although geologic conditions and over-stressing play major roles in roof falls, an especially common cause of falls of shaly roof is the gradual deterioration of the shale itself. The culprit in such deteriorations is the hydrophilic nature of the shale's clay mineral components, a trait causing some of the clay minerals to swell due to absorption of water from the atmosphere. Moisture enters the annular space between the bolt rod and the walls of the borehole, and then condenses on the cooler surfaces. It can then be absorbed by the shale through capillary attraction into micro cracks and bedding planes. When the condensation forms at the anchorage level, it can cause weakening of the rock, especially where the shale is under high stress with the anchor shell. To prevent migration of moisture into the roof through bolt holes, a patented plastic plug has been designed to seal the annular space between the rock and the bolt rod at the entrance of the hole. The plug consists of two halves that snap in and lock together. It can be assembled on a bolt rod in just three seconds by squeezing the two halves together just before the bolt is inserted into the bolt hole. The external and internal flanges of the plug create tight contact between the perimeter of the hole and the bolt rod, thereby sealing the annular space between the rock and the roof bolt at the entrance of the hole.

  14. Thrust bolting: roof bolt support apparatus

    DOEpatents

    Tadolini, Stephen C. (Lakewood, CO); Dolinar, Dennis R. (Golden, CO)

    1992-01-01

    A method of installing a tensioned roof bolt in a borehole of a rock formation without the aid of a mechanical anchoring device or threaded tensioning threads by applying thrust to the bolt (19) as the bonding material (7') is curing to compress the strata (3) surrounding the borehole (1), and then relieving the thrust when the bonding material (7') has cured.

  15. Development of design guidelines and roof-control standards for coal-mine roofs

    Microsoft Academic Search

    Unal

    1983-01-01

    Three of the most crucial problems still facing the mining-engineering profession today are that of finding better anchorage testing procedures, effective roof-stability monitoring systems and rationally based design guidelines. First the feasibility of new anchorage-testing procedures and roof-stability monitoring techniques has been investigated through a series of laboratory experiments, utilizing a special instrumented facility and an acoustic emission (AE) monitoring

  16. Thermal performance of gaseous-helium-purged tank-mounted multilayer insulation system during ground-hold and space-hold thermal cycling and exposure to water vapor

    NASA Technical Reports Server (NTRS)

    Sumner, I. E.

    1978-01-01

    An experimental investigation was conducted to determine (1) the ground-hold and space-hold thermal performance of a multilayer insulation (MLI) system mounted on a spherical, liquid-hydrogen propellant tank and (2) the degradation to the space-hold thermal performance of the insulation system that resulted from both thermal cycling and exposure to moisture. The propellant tank had a diameter of 1.39 meters (4.57ft). The MLI consisted of two blankets of insulation; each blanket contained 15 double-aluminized Mylar radiation shields separated by double silk net spacers. Nineteen tests simulating basic cryogenic spacecraft thermal (environmental) conditions were conducted. These tests typically included initial helium purge, liquid-hydrogen fill and ground-hold, ascent, space-hold, and repressurization. No significant degradation of the space-hold thermal performance due to thermal cycling was noted.

  17. Increased Ocular Pulse Amplitude Associated with Unilateral Dysgenesis of the Orbital Roof

    PubMed Central

    Vira, Ami Shah; Mahmoud, Ashraf M.; Roberts, Cynthia J.; Katz, Steven E.

    2015-01-01

    Introduction Two patients (one with neurofibromatosis type 1) presented with unilateral ocular pulsation. Methods A CT scan of the orbits revealed extensive dysgenesis of the orbital roof with herniation of the frontal lobe into the orbit in both cases. PASCAL dynamic contour tonometry was performed. Results The ipsilateral ocular pulse amplitude (OPA) was greater than the contralateral side, and the ocular pulse waveform morphology more closely approximated the known intracranial waveform in these patients. Conclusions We hypothesize that the greater OPA was due to stronger transmission of the intracranial pressure waveform amplitude and morphology in the absence of the orbital roof.

  18. Analyses of flight model spacecraft performance during thermal-vacuum tests

    NASA Technical Reports Server (NTRS)

    Timmins, A. R.; Heuser, R. E.; Strain, J. C.

    1972-01-01

    Malfunction data from the thermal-vacuum tests of 39 flight-model spacecraft were analyzed. The results are interpreted in terms of the test variables, and in terms of the spacecraft performance. The malfunction data are correlated with the test time as a single variable, and also with the composite variable of time plus temperature. The improvement in spacecraft performance is examined by means of malfunction rates, malfunctions per spacecraft, and the probability of no failure related to test time. The minimum thermal-vacuum test profile required for Goddard Space Flight Center spacecraft is verified, and the probability of a defect remaining undetected is estimated.

  19. Analyses of flight model spacecraft performance during thermal-vacuum tests

    NASA Technical Reports Server (NTRS)

    Timmins, A. R.; Heuser, R. E.; Strain, J. C.

    1973-01-01

    Malfunction data from the thermal-vacuum tests of 39 flight-model spacecraft have been analyzed. The results are interpreted in terms of the test variables and the spacecraft performance. The malfunction data are correlated with the test time as a single variable, and also with the composite variable of time plus temperature. The improvement in spacecraft performance is examined by means of malfunction rates, malfunctions per spacecraft, and the probability of no failure related to test time. The minimum thermal-vacuum test profile required for Goddard Space Flight Center spacecraft is verified, and the probability of a defect remaining undetected is estimated.

  20. Predicting and evaluating the performance of ice-harvesting thermal energy storage systems

    SciTech Connect

    Knebel, D.E. [Univ. of Wisconsin, Madison, WI (United States). Thermal Storage Applications Research Center

    1995-08-01

    Ice-harvesting thermal storage systems have been applied to a large number of cool thermal storage systems. Field verification of the performance of these systems is difficult because direct methods of weighing the ice are impractical in all but the smallest systems. This paper discusses the operating characteristics of ice-harvesting equipment using heat-initiated defrost cycles, the process of ice formation, a simplified model for predicting ice-making performance, and defrost energy requirements. The result of this analysis is the prediction of the net rated ice-making capacity of the system in the ice-making mode.

  1. Does the thermal plasticity of metabolic enzymes underlie thermal compensation of locomotor performance in the eastern newt (Notophthalmus viridescens)?

    PubMed

    Mineo, Patrick M; Schaeffer, Paul J

    2015-01-01

    Eastern newts (Notophthalmus viridescens) upregulate the metabolic capacity of skeletal muscle in winter to compensate for thermodynamic effects on metabolism. However, whether this compensation facilitates locomotor performance at low temperature is unknown. Therefore, our aim was to determine if thermal acclimation of metabolic enzymes in muscle benefits locomotion. Eastern newts from southern Ohio were acclimated to cold (5°C, 10:14 L:D) or warm (25°C, 14:10 L:D) conditions for 12 weeks. Following acclimation, we measured the locomotor performance (burst speed and time until exhaustion) and the activities of metabolic enzymes in skeletal muscle at 5-30°C. Creatine kinase (CK) activity in skeletal muscle was higher in cold compared to warm-acclimated newts, and cold-acclimated newts had a higher burst speed at low temperature compared to warm-acclimated newts. At low temperature, time until exhaustion was higher in cold compared to warm-acclimated newts, but the activities of citrate synthase (CS) and cytochrome c oxidase (CCO) in muscle were lower in cold compared to warm-acclimated newts. Together, these results demonstrate that eastern newts compensate for the effects of low temperature on locomotor performance. Whereas thermal compensation of CK activity is correlated with burst locomotion at low temperature, aerobic enzymes in skeletal muscle (CS and CCO) are not linked to compensation of sustained locomotion. PMID:25382581

  2. Influence of surface treatment of components on thermal radiation performance in infrared optical systems

    NASA Astrophysics Data System (ADS)

    Luo, Wen-fei; Wu, Jian-peng; Peng, Jia-qi; Zhang, Bin

    2014-09-01

    The existence of self-generated thermal radiation in infrared optical systems exhibits a great impact to the extraction of target signal and further degrades the signal-to-noise ratio (SNR), thus making the self-generated thermal radiation one of the important factors affecting the detective property. In this paper, a refraction-reflection optical system has been taken as an example and the three-dimensional simulation model has been built up using the ASAP optical analysis software. On this basis, the influence of the surface roughness, the level of the optics contaminated by the particles with the uniform and non-uniform distributions, the treatment of the mechanical surface (such as blacking, polishing, roughening) on the self-generated thermal radiation have been focused on discussion. Moreover, the thermal radiation of the system has been evaluated by the effective emissivity. The results indicate that the effective emissivity varies with different surface treatment. The self-generated thermal radiation is more and more serious with the increasing of the effective emissivity, resulting in great difficulty in obtaining and analyzing the target signal. It follows that the surface treatment of components exhibits a significant effect on the stray radiation performance in infrared optical systems. Consequently, appropriate treatments should be taken to diminish the self-generated thermal radiation in order to meet the requirements of the stray radiation performance in practical applications.

  3. Passive solar/earth sheltered office/dormitory cooling season thermal performance

    SciTech Connect

    Christian, J.

    1984-01-01

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

  4. Development of a performance evaluation facility for fire fighting thermal imagers

    NASA Astrophysics Data System (ADS)

    Amon, Francine; Benetis, Vytenis; Kim, Jungho; Hamins, Anthony

    2004-08-01

    The Building and Fire Research Laboratory (BFRL) at the National Institute of Standards and Technology (NIST) is developing a new bench-scale testing facility and methods to evaluate the performance of thermal imagers used by fire fighters to search for victims and hot spots in burning structures. A larger-scale laboratory testing facility was constructed in 2002. This facility was used to determine the effects of water sprays on the imaging performance of a selection of thermal imagers. A new, smaller-scale laboratory facility, currently under construction, will provide a carefully controlled laboratory setting in which aspects of the environment inside a burning structure are simulated as closely as possible. It will also serve as a test bed for new technology. An evaluation of the performance of different thermal imaging detector technologies under field conditions is also underway. Results of this project will provide a quantifiable physical and scientific basis upon which industry standards for imaging performance, testing protocols and reporting practices related to the performance of thermal imaging cameras can be developed. In this paper a description of the testing facilities, including both generations of laboratory apparatus is presented.

  5. VO2 nanorods for efficient performance in thermal fluids and sensors

    NASA Astrophysics Data System (ADS)

    Dey, Kajal Kumar; Bhatnagar, Divyanshu; Srivastava, Avanish Kumar; Wan, Meher; Singh, Satyendra; Yadav, Raja Ram; Yadav, Bal Chandra; Deepa, Melepurath

    2015-03-01

    VO2 (B) nanorods with average width ranging between 50-100 nm are synthesized via a hydrothermal method and the post hydrothermal treatment drying temperature is found to be influential in their overall phase and growth morphology evolution. The nanorods with unusually high optical bandgap for a VO2 material are effective in enhancing the thermal performance of ethylene glycol nanofluids over a wide temperature range as is indicated by the temperature dependent thermal conductivity measurements. Humidity and LPG sensors fabricated using the VO2 (B) nanorods bear testament to their efficient sensing performance, which can be partially attributed to the mesoporous nature of the nanorods.VO2 (B) nanorods with average width ranging between 50-100 nm are synthesized via a hydrothermal method and the post hydrothermal treatment drying temperature is found to be influential in their overall phase and growth morphology evolution. The nanorods with unusually high optical bandgap for a VO2 material are effective in enhancing the thermal performance of ethylene glycol nanofluids over a wide temperature range as is indicated by the temperature dependent thermal conductivity measurements. Humidity and LPG sensors fabricated using the VO2 (B) nanorods bear testament to their efficient sensing performance, which can be partially attributed to the mesoporous nature of the nanorods. Electronic supplementary information (ESI) available: Plots representing the actual ratio Knf/KEG (Knf is the thermal conductivity of the nanofluid and KEG being thermal conductivity of the base fluid) across the entire experimental temperature range of 20 to 80 °C, table representing a comparison of performance of the VO2 sensor towards different gases. See DOI: 10.1039/c4nr06032f

  6. Large-scale changes in thermal sensitivity of flight performance during adult maturation in a dragonfly

    PubMed

    Marden

    1995-01-01

    Newly emerged adult dragonflies are physiologically immature in a number of ways, including the mass, ultrastructure and biochemistry of their flight muscles. In Libellula pulchella dragonflies, adult maturation of flight muscle is accompanied by striking changes in thermal physiology. Vertical force production during fixed flight attempts in newly emerged adults (tenerals) shows a broad plateau of near-peak performance, first attained at cool thoracic temperatures (typically 28­34 °C) and maintained up to thoracic temperatures of 40­45 °C [mean optimal thoracic temperature (OTT)=34.6 °C; mean upper lethal temperature (ULT)=45.3 °C]. In contrast, fully mature adults show narrow thermal sensitivity curves, wherein peak performance is approached only within a few degrees of the thermal optimum, which invariably occurs at hot thoracic temperatures (38­50 °C; mean OTT=43.5 °C; mean ULT=48.6 °C). These changes in the shape and position of thermal performance curves are compared with predictions from hypotheses for the evolution of thermal sensitivity. PMID:9320006

  7. DISPERSION OF ROOF-TOP EMISSIONS FROM ISOLATED BUILDINGS. A WIND TUNNEL STUDY

    EPA Science Inventory

    A fluid modeling study of the dispersion of roof-top emissions from rectangular buildings was performed in the meteorological wind tunnel of the EPA Fluid Modeling Facility. The basic building shape was a 0.18 meter cube. Variations included a building twice as wide and buildings...

  8. Composite synthetic roofing structure with integral solar collector

    SciTech Connect

    Gould, W.M.

    1981-06-16

    A form-molded synthetic foam roofing section or structure is described, having a solar-collecting insert or panel incorporated therein with a relatively broad undersurface and an exposed surface configured to resemble interlocked and overlapping roofing shingles which are united to support a surface such as wood, metal, etc. During the molding process. The roofing structure may be affixed by any conventional means, such as nails or adhesives, to roof boards, rafters or over old existing roof structures with adjacent roofing sections interconnected by appropriate inlets and outlets for the solar panel insert. Solar heat-collecting fluid may be circulated through the solar panel inserts in a conventional manner. Connecting tubes are provided for connecting the solar panel inserts in adjacent roofing sections and terminal connectors are compatible with all circulating systems.

  9. Green roofs as a means of pollution abatement.

    PubMed

    Rowe, D Bradley

    2011-01-01

    Green roofs involve growing vegetation on rooftops and are one tool that can help mitigate the negative effects of pollution. This review encompasses published research to date on how green roofs can help mitigate pollution, how green roof materials influence the magnitude of these benefits, and suggests future research directions. The discussion concentrates on how green roofs influence air pollution, carbon dioxide emissions, carbon sequestration, longevity of roofing membranes that result in fewer roofing materials in landfills, water quality of stormwater runoff, and noise pollution. Suggestions for future directions for research include plant selection, development of improved growing substrates, urban rooftop agriculture, water quality of runoff, supplemental irrigation, the use of grey water, air pollution, carbon sequestration, effects on human health, combining green roofs with complementary related technologies, and economics and policy issues. PMID:21074914

  10. Emission Control Technologies, Performance/Durability Issues Presentation Thermal Deactivation Mechanisms of Fully-Formulated Lean NOx

    E-print Network

    Pennycook, Steve

    Emission Control Technologies, Performance/Durability Issues ­ Presentation Thermal Deactivation performance of thermally-aged LNTs is evaluated at temperatures of 200, 300, and 400o C. All performance evaluations are carried out in the presence of 300ppm NO, 60s/5s lean/rich cycles and at a gas hourly space

  11. A mathematical model for predicting the thermal performance of building envelope

    SciTech Connect

    Yilmaz, A.Z.

    1983-12-01

    As it is well known, in a room, mean radiant temperature, which can be calculated in reference to the room dimensions, room location and the inner surface temperatures of the building envelope and the partitions surrounding the room, is one of the factors affecting bioclimatic users' comfort and even if the indoor air temperature has a costant value, due to the physical properties of the envelope consisting of opaque and transparent components, the inner surface temperatures and mean radiant temperature vary with the rate of heat flow through these components. Therefore the thermal performance of the building envelope should not be analyzed independently from room dimensions, room location and inner surface temperatures. In this study, a new model, which is based on analyzing the thermal performance of the envelope by evaluating the mean radiant temperature in terms of its required value (for thermal comfort), has been developed.

  12. A mathematical model for predicting the thermal performance of building envelope

    SciTech Connect

    Yilmaz, A.Z.

    1983-12-01

    As it is well known, in a room, mean radiant temperature, which can be calculated in reference to the room dimensions, room location and the inner surface temperatures of the building envelope and the partitions surrounding the room, is one of the factors affecting bioclimatic users' comfort and even if the indoor air temperature has a constant value, due to the physical properties of the envelope consisting of opaque and transparent components, the inner surface temperatures and mean radiant temperature vary with the rate of heat flow through these components. Therefore the thermal performance of the building envelope should not be analyzed independently from room dimensions, room location and inner surface temperatures. In this study, a new model, which is based on analyzing the thermal performance of the envelope by evaluating the mean radiant temperature in terms of its required value (for thermal comfort), has been developed.

  13. Thermal flow monitor: Design and performance in acid rain stacks 1991--1994

    SciTech Connect

    Groce, P.J. [Kurz Instruments, Inc., Monterey, CA (United States)

    1995-12-31

    Implementation of Title IV of the Clean Air Act greatly expanded the market of mass flow measurement in utility flue gas ducts and stacks. Lessons learned from recent experience in this demanding application resulted in the rapid evolution of equipment designed to ensure accuracy, reliability and ease of maintenance. Thermal technology, one of three accepted methods of mass flow measurement, has proven to be an extremely accurate and reliable means of measuring mass flow for utility emissions monitoring purposes. This paper offers an overview of thermal flow monitor performance in Part 75 utility applications for Phase 1 and 2 flow measurement. The paper first addresses the history and evaluation of thermal technology for CEM applications, Next, the paper outlines performance results.

  14. The influence of thermally assisted tunneling on the performance of charge trapping memory

    NASA Astrophysics Data System (ADS)

    Peng, Ya-Hua; Liu, Xiao-Yan; Du, Gang; Liu, Fei; Jin, Rui; Kang, Jin-Feng

    2012-07-01

    We evaluate the influence of the thermally assisted tunneling (TAT) mechanism on charge trapping memory (CTM) cell performance by numerical simulation, and comprehensively analyse the effects of the temperature, trap depth, distribution of trapped charge, gate voltage and parameters of TAT on erasing/programming speed and retention performance. TAT is an indispensable mechanism in CTM that can increase the detrapping probability of trapped charge. Our results reveal that the TAT effect causes the sensitivity of cell performance to temperature and it could affect the operational speed, especially for the erasing operation. The results show that the retention performance degrades compared with when the TAT mechanism is ignored.

  15. Performance characteristics of a thermal energy storage module - A transient PCM\\/forced convection conjugate analysis

    Microsoft Academic Search

    Y. Cao; A. Faghri

    1991-01-01

    The performance of a thermal energy storage module is simulated numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid with low Prandtl numbers are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. The numerical results show that module geometry is crucial

  16. Design space exploration for multicore architectures: a power\\/performance\\/thermal view

    Microsoft Academic Search

    Matteo Monchiero; Ramon Canal; Antonio González

    2006-01-01

    Multicore architectures are ruling the recent microprocessor design trend. This is due to different reasons: better performance, thread- level parallelism bounds in modern applications, ILP diminishing returns, better thermal\\/power scaling (many small cores dissipate less than a large and complex one); and, ease and reuse of design. This paper presents a thorough evaluation of multicore architec- tures. The architecture we

  17. Early-in-life thermal performance of UOâ--PuOâ fast reactor fuel

    Microsoft Academic Search

    R. B. Baker; R. D. Leggett

    1979-01-01

    Results from the combined analyses of two thermal performance tests, HEDL P-19 and HEDL P-20 are described. The tests were designed to provide data on the power required to cause incipient fuel melting early in life under conditions prototypic of FFTF driver fuel pins and similar FBR fuel systems.

  18. Thermal cure effects on electrical performance of nanoparticle silver inks Julia R. Greer *, Robert A. Street

    E-print Network

    Greer, Julia R.

    . 2. Experimental results 2.1. Materials and measurements The specific silver nano-ink used in this work consists of $40 nm silver particles with $5 nm polymer coating in an organic solvent. In ourThermal cure effects on electrical performance of nanoparticle silver inks Julia R. Greer *, Robert

  19. Extending Cooling Tower thermal Performance Prediction Using a Liquid-Side Film Resistance Model

    Microsoft Academic Search

    T. J. MARSEILLE; J. S. SCHLIESING; D. M. BELL; B. M. JOHNSON

    1991-01-01

    Current models used to analyze the thermal performance of cooling towers assume that the air\\/water interfacial temperature is equivalent to the bulk temperature of the water, or, in other words, that the liquid-side film resistance is negligible. This assumption is a possible source of the dependence on inlet hot water temperatures found in cooling tower packing heat and mass transfer

  20. Novel load responsive multilayer insulation with high in-atmosphere and on-orbit thermal performance

    NASA Astrophysics Data System (ADS)

    Dye, S.; Kopelove, A.; Mills, G. L.

    2012-04-01

    Aerospace cryogenic systems require lightweight, high performance thermal insulation to preserve cryopropellants both pre-launch and on-orbit. Current technologies have difficulty meeting all requirements, and advances in insulation would benefit cryogenic upper stage launch vehicles, LH2 fueled aircraft and ground vehicles, and provide capabilities for sub-cooled cryogens for space-borne instruments and orbital fuel depots. This paper reports the further development of load responsive multilayer insulation (LRMLI) that has a lightweight integrated vacuum shell and provides high thermal performance both in-air and on-orbit. LRMLI is being developed by Quest Product Development and Ball Aerospace under NASA contract, with prototypes designed, built, installed and successfully tested. A 3-layer LRMLI blanket (0.63 cm thick, 77 K cold, 295 K hot) had a measured heat leak of 6.6 W/m2 in vacuum and 40.6 W/m2 in air at one atmosphere. In-air LRMLI has an 18× advantage over Spray On Foam Insulation (SOFI) in heat leak per thickness and a 16× advantage over aerogel. On-orbit LRMLI has a 78× lower heat leak than SOFI per thickness and 6× lower heat leak than aerogel. The Phase II development of LRMLI is reported with a modular, flexible, thin vacuum shell and improved on-orbit performance. Structural and thermal analysis and testing results are presented. LRMLI mass and thermal performance is compared to SOFI, aerogel and MLI over SOFI.