These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Thermal Performance of Vegetative Roofing Systems  

SciTech Connect

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

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

2010-01-01

2

Effect of Surface Mass on Roof Thermal Performance  

E-print Network

The roof of a building is exposed to the most severe environment that is experienced by any component of a building envelope. Diurnal peak surface temperatures of 140 to 185 °F are not uncommon. The addition of thermal mass to the exterior surface...

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

1988-01-01

3

Thermal and Energy Performance of Conditioned Building Due To Insulated Sloped Roof  

NASA Astrophysics Data System (ADS)

For low-rise buildings in equatorial region, the roof is exposed to solar radiation longer than other parts of the envelope. Roofs are to be designed to reject heat and moderate the thermal impact. These are determined by the design and construction of the roofing system. The pitch of roof and the properties of construction affect the heat gain into the attic and subsequently the indoor temperature of the living spaces underneath. This finally influences the thermal comfort conditions of naturally ventilated buildings and cooling load of conditioned buildings. This study investigated the effect of insulated sloping roof on thermal energy performance of the building. A whole-building thermal energy computer simulation tool, Integrated Environmental Solution (IES), was used for the modelling and analyses. A building model with dimension of 4.0 m × 4.0 m × 3.0 m was designed with insulated roof and conventional construction for other parts of the envelope. A 75 mm conductive insulation material with thermal conductivity (k-value) of 0.034 Wm-1K-1 was installed underneath the roof tiles. The building was modelled with roof pitch angles of 0° , 15°, 30°, 45°, 60° and simulated for the month of August in Malaysian climate conditions. The profile for attic temperature, indoor temperature and cooling load were downloaded and evaluated. The optimum roof pitch angle for best thermal performance and energy saving was identified. The results show the pitch angle of 0° is able to mitigate the thermal impact to provide the best thermal condition with optimum energy savings. The maximum temperature difference between insulated and non-insulted roof for attic (AtticA-B) and indoor condition (IndoorA-B) is +7.8 °C and 0.4 °C respectively with an average energy monthly savings of 3.9 %.

Irwan, Suhandi Syiful; Ahmed, Azni Zain; Zakaria, Nor Zaini; Ibrahim, Norhati

2010-07-01

4

Energy performance of fabric roofs  

Microsoft Academic Search

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

Beitin

1982-01-01

5

A Computer Analysis of the Annual Thermal Performance of a Roof System with Slightly Wet Fibrous Glass Insulation under Transient Conditions  

Microsoft Academic Search

Field and laboratory results from short-term summer tests have sug gested that small amounts of moisture in fibrous glass roof insulations can have a sig nificant effect on the dynamic thermal performance of roof systems. These results have been reproduced using the transient heat and mass transfer mathematical model. Subsequently, the model has been used to simulate roof performance in

Carsten R. Pedersen; George E. Courville

1991-01-01

6

Prolong Your Roof's Performance: Roof Asset Management.  

ERIC Educational Resources Information Center

Discusses the roof asset management process for maintaining a roof system's integrity and value in a cost-effective manner. Included is a breakdown of roofing surface characteristics for multiply and single ply roofing systems. (GR)

Teitsma, Jerry

2001-01-01

7

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

E-print Network

This paper presents an overview of results from experimental research conducted at FSEC's Flexible Roofing Facility in the summer of 2002. The Flexible Roof Facility (FRF) is a test facility in Cocoa, Florida designed to evaluate a combination...

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

2004-01-01

8

Performance of antisolar insulated roof system  

Microsoft Academic Search

Rooms with concrete slab roofs directly exposed to the sun become unbearably hot during summer and very cold during winter. Huge amounts of energy are required to keep them comfortable. Application of thermal insulation on roofs significantly reduces energy required for heating and cooling. The effectiveness of roof insulations may be further enhanced if a layer of antisolar coating is

Irshad Ahmad

2010-01-01

9

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

E-print Network

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

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

2010-01-01

10

Analysis of asphalt-based roof systems using thermal analysis  

SciTech Connect

Asphalt is used extensively in roofing applications. Traditionally, it is used in a built-up roof system, where four or five plies are applied in conjunction with asphalt. This is labour intensive and requires good quality assurance on the roof top. Alternatively, asphalt can be used in a polymer-modified sheet where styrene-butadiene-styrene (SBS) or atactic polypropylene (APP) are added to the asphalt shipped in a roll where reinforcement (e.g., glass fibre mat) has been added. Regardless of the system used, the roof must be able to withstand the environmental loads such UV, heat, etc. Thermoanalytical techniques such as DSC, DMA, TMA and TG/DTA are ideally suited to monitor the weathering of asphalt. This paper presents data obtained using these techniques and shows how the performance of asphalt-based roof systems can be followed by thermal analysis.

Paroli, R.M.; Delgado, A.H. [Inst. for Research in Construction, Ottawa, Ontario (Canada)

1996-10-01

11

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

Microsoft Academic Search

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

Ekaterini Eumorfopoulou; Dimitris Aravantinos

1998-01-01

12

Energy Performance Aspects of a Florida Green Roof  

E-print Network

ENERGY PERFORMANCE ASPECTS OF A FLORIDA GREEN ROOF Jeffrey K. Sonne Senior Research Engineer Florida Solar Energy Center Cocoa, FL ABSTRACT Previous green roof studies have found that planted roofs significantly reduce roof temperatures... 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...

Sonne, J.

2006-01-01

13

Energy Performance Aspects of a Florida Green Roof Part 2  

E-print Network

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...

Sonne, J.; Parker, D.

14

Wind performance evaluation of fully bonded roofing assemblies  

Microsoft Academic Search

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

A. Baskaran; S. Molleti; M. Sexton

2008-01-01

15

Analysis of asphalt-based roof systems using thermal analysis  

SciTech Connect

Asphalt has been used in the construction of roads and houses for thousands of years. The properties of asphalt has rendered it quite useful in roofing and waterproofing applications. The most popular use of asphalt in industrial roofing is in the form of a built-up roof or modified-bituminous sheet. This type of roof consists of asphalt, reinforcement and aggregate which is used to protect the asphalt from ultraviolet rays. All materials have their weaknesses and asphalt is no exception. A good asphalt (e.g., low asphaltene content) must be used to ensure the quality and low-temperature performance of roofing asphalts. Polymer additives can be added. The objective of this work was to demonstrate the utility of termogravimetry and dynamic mechanical analysis in establishing the durability of modified bituminous membranes.

Paroli, R.M.; Delgado, A.H. [National Research Council of Canada, Ottawa, Ontario (Canada)

1996-12-31

16

Hygrothermal Performance of West Coast Wood Deck Roofing System  

SciTech Connect

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

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

2014-02-01

17

Performance of dryland and wetland plant species on extensive green roofs  

PubMed Central

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

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

2011-01-01

18

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

E-print Network

Manager Metro Roof Products Oceanside, California Achilles Karagiozis Research Scientist Oak Ridge National Laboratory Oak Ridge, Tennessee ABSTRACT Field studies were conducted on several attic assemblies having stone-coated metal shake roofs... and documenting the energy savings and durability of stone-coated metal roofs with shake and S-mission profiles. Stone-coated metal is made from pre-primed 26-gauge galvanized steel that is coated with a layer of stone chips (Figure 1). An acrylic base coat...

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

2006-01-01

19

Green roof hydrologic performance and modeling: a review.  

PubMed

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

Li, Yanling; Babcock, Roger W

2014-01-01

20

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

E-print Network

A pair of comparative testing rooms (one with an ordinary roof and the other with a planting roof) was established in our laboratory, and in- situ measurement (in summer) data have been collected and treated. The indoor thermal environment...

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

2006-01-01

21

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

PubMed

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

Burszta-Adamiak, E; Mrowiec, M

2013-01-01

22

The Equivalent Thermal Resistance of Tile Roofs with and without Batten Systems  

SciTech Connect

Clay and concrete tile roofs were installed on a fully instrumented attic test facility operating in East Tennessee s climate. Roof, attic and deck temperatures and heat flows were recorded for each of the tile roofs and also on an adjacent attic cavity covered with a conventionally pigmented and direct-nailed asphalt shingle roof. The data were used to benchmark a computer tool for simulation of roofs and attics and the tool used to develop an approach for computing an equivalent seasonal R-value for sub-tile venting. The approach computed equal heat fluxes through the ceilings of roofs having different combinations of surface radiation properties and or building constructions. A direct nailed shingle roof served as a control for estimating the equivalent thermal resistance of the air space. Simulations were benchmarked to data in the ASHRAE Fundamentals for the thermal resistance of inclined and closed air spaces.

Miller, William A [ORNL] [ORNL

2013-01-01

23

Modelling of green roof hydrological performance for urban drainage applications  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

24

A modelling study of long term green roof retention performance.  

PubMed

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

Stovin, Virginia; Poë, Simon; Berretta, Christian

2013-12-15

25

Air intrusion and its impact on energy performance of roofing assemblies  

Microsoft Academic Search

Air intrusion through roof assembly is a concern for wind uplift resistance and life-cycle performance of roofs. Airflow control is usually achieved by the installation of an air barrier\\/retarder in the roofing assembly. Even though the concept of air barrier\\/retarder and air barrier systems has been around for decades, it is still considered a new notion to the roofing industry.

Suda Molleti; Bas A. Baskaran; Pascal Beaulieu; David Van Reenen

2010-01-01

26

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

NASA Astrophysics Data System (ADS)

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

Nagengast, Amy L.

27

Validation of the thermal effect of roof with the Spraying and green plants in an insulated building  

SciTech Connect

In recent years, roof-spraying and rooftop lawns have proven effective on roofs with poor thermal insulation. However, the roofs of most buildings have insulating material to provide thermal insulation during the winter. The effects of insulation has not previously been quantified. In this study, the authors collected measurements of an insulated building to quantify the thermal effects of roof-spraying and rooftop lawns. Roof-spraying did not significantly reduce cooling loads and required significant amounts of water. The conclusion is that roof spraying is not suitable for buildings with well-insulated roofs. Rooftop lawns, however, significantly stabilized the indoor temperature while additionally helping to mitigate the heat island phenomenon.

Zhou, Nan; Gao, Weijun; Nishida, Masaru; Ojima, Toshio

2004-08-08

28

Equilibrium thermal characteristics of a building integrated photovoltaic tiled roof  

SciTech Connect

Photovoltaic (PV) modules attain high temperatures when exposed to a combination of high radiation levels and elevated ambient temperatures. The temperature rise can be particularly problematic for fully building integrated PV (BIPV) roof tile systems if back ventilation is restricted. PV laminates could suffer yield degradation and accelerated aging in these conditions. This paper presents a laboratory based experimental investigation undertaken to determine the potential for high temperature operation in such a BIPV installation. This is achieved by ascertaining the dependence of the PV roof tile temperature on incident radiation and ambient temperature. A theory based correction was developed to account for the unrealistic sky temperature of the solar simulator used in the experiments. The particular PV roof tiles used are warranted up to an operational temperature of 85 C, anything above this temperature will void the warranty because of potential damage to the integrity of the encapsulation. As a guide for installers, a map of southern Europe has been generated indicating locations where excessive module temperatures might be expected and thus where installation is inadvisable. (author)

Mei, L.; Gottschalg, R.; Loveday, D.L. [Centre for Renewable Energy Systems Technology (CREST), Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom); Infield, D.G. [Institute of Energy and Environment, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, G1 1XW (United Kingdom); Davies, D.; Berry, M. [Solarcentury, 91-94 Lower Marsh Waterloo, London, SE1 7AB (United Kingdom)

2009-10-15

29

Minimal watering regime impacts on desert adapted green roof plant performance  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

30

Theoretical\\/experimental comparison of heat flux reduction in roofs achieved through the use of reflective thermal insulators  

Microsoft Academic Search

In tropical countries, the greatest thermal gain occurs through the roof of a house. In Brazil, the use of an asbestos-cement roof without a ceiling is very common. Thus, there is intense heat transfer to the internal environment, which may cause thermal discomfort to the inhabitants. One way to reduce the heat flux is the use of radiant barriers, which

Caren Michels; Roberto Lamberts; Saulo Güths

2008-01-01

31

Observation and analysis of protected membrane roofing systems  

Microsoft Academic Search

Two performance indicators, effectiveness and thermal efficiency, are defined and used to evaluate the year-round performance of three protected membrane roofs in Alaska and New Hampshire. Effectiveness is a measure of the deviations of ceiling temperatures from a yearly average, with large diviations indicating erratic performance in the roofing-insulation system and small departures indicating a thermally stable system. Thermal efficiency,

D. Schaefer; E. T. Larsen; H. W. C. Aamot

1977-01-01

32

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

E-print Network

1 Title: Evaluation of Vegetative Roofs' Performance on Energy Consumption in Hot and Humid Climates Primary Author: Name: Mona Azarbayjani Title: Architectural PhD candidate University of Illinois at Urbana Champaign / School... in Europe proved to be beneficial. However, in the US they are not widespread. Previous studies have concluded that the main obstacle that makes architects, developers, etc. reluctant to introduce vegetative roofs is their preference for the traditional...

Anderson, J.; Azarbayjani, M.

33

Photovoltaic Roofs  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

34

Effect of roof slope and thickness on the performance of a saltstone vault  

SciTech Connect

At the Savannah River Site, low-level radioactive decontaminated salt solution is mixed with slag, flyash, and cement to form a grout-like material called ``Saltstone.`` The Saltstone is poured into concrete vaults constructed at the Saltstone Disposal Facility (SDF). The SDF is designed for the release of contaminants in a slow, controlled manner over thousands of years. The impact of SDF on groundwater has been studied in a radiological performance assessment (PA). Groundwater models were used to predict the fluid flow and contaminant transport at SDF. The models predicted a spatial contaminant concentration distribution in groundwater as a function of time. This study focuses on the roof configuration of Saltstone vault, with special interests in cost-effectiveness. We conducted a study to evaluate the effect of roof slope and thickness on the performance of a Saltstone vault. Four roof configurations were simulated. The tool used for the simulation was ECLIPSE, a finite-difference petroleum reservoir engineering code with an environmental tracer option. Nitrate was used as the ``tracer`` contaminant. In this study, ECLIPSE solves the two-phase two-dimensional flow and transport problem up to 10,000 years. This paper describes a modeling study used to evaluate roof design options for the Saltstone vault.

Yu, A.D.; Lam, Poh-Sang; Hsu, R.H.

1995-09-01

35

Advanced Energy Efficient Roof System  

SciTech Connect

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

Jane Davidson

2008-09-30

36

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...

37

Extracting Roof Parameters and Heat Bridges Over the City of Oldenburg from Hyperspectral, Thermal, and Airborne Laser Scanning Data  

NASA Astrophysics Data System (ADS)

Remote sensing methods are used to obtain different kinds of information about the state of the environment. Within the cooperative research project HiReSens, funded by the German BMBF, a hyperspectral scanner, an airborne laser scanner, a thermal camera, and a RGB-camera are employed on a small aircraft to determine roof material parameters and heat bridges of house tops over the city Oldenburg, Lower Saxony. HiReSens aims to combine various geometrical highly resolved data in order to achieve relevant evidence about the state of the city buildings. Thermal data are used to obtain the energy distribution of single buildings. The use of hyperspectral data yields information about material consistence of roofs. From airborne laser scanning data (ALS) digital surface models are inferred. They build the basis to locate the best orientations for solar panels of the city buildings. The combination of the different data sets offers the opportunity to capitalize synergies between differently working systems. Central goals are the development of tools for the collection of heat bridges by means of thermal data, spectral collection of roofs parameters on basis of hyperspectral data as well as 3D-capture of buildings from airborne lasers scanner data. Collecting, analyzing and merging of the data are not trivial especially not when the resolution and accuracy is aimed in the domain of a few decimetre. The results achieved need to be regarded as preliminary. Further investigations are still required to prove the accuracy in detail.

Bannehr, L.; Luhmann, Th.; Piechel, J.; Roelfs, T.; Schmidt, An.

2011-09-01

38

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

SciTech Connect

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

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

2011-01-01

39

Effectiveness of Cool Roof Coatings with Ceramic Particles  

SciTech Connect

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

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

2011-01-01

40

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

SciTech Connect

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).

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

1993-10-01

41

A Dynamic Mathematical Model to Predict the Performance of Passive Cooling System by Evapo-Reflective Roof for Hot Dry Climates  

Microsoft Academic Search

A dynamic mathematical model used to predict the performance of passive cooling system by evapo-reflective roof in buildings for hot arid climates has been developed. The cooling system consists of a roof composed of concrete ceiling and flat aluminium plate, separated with air space partially filled with rocks and small quantity of water. Low emissive aluminium sheet with white painting

H. Bencheikh; A. Bouchair

2004-01-01

42

The effect of modified roofing on the milk yield and reproductive performance of heat-stressed dairy cows under hot-humid conditions.  

PubMed

The objective was to measure the effects of cooling techniques (shade cloth vs. normal roof) on performance and physiology of 16 Friesian crossbred cows (87.5% Holstein Friesian × 12.5% Brahman) located at Sakol Nakhon Livestock Research and Testing Station, Department of Livestock Development, Ministry of Agriculture and Cooperatives (Sakol Nakhon, Thailand). They were divided randomly into two groups of eight. The two groups were used to evaluate the effects of modified roofing (normal roof fitted with woven polypropylene shade cloth) on the subjects' milk yield and reproductive performance under hot humid conditions. Results indicated that the modified roofing offered a more efficient way to minimize heat stress than the normal roof. The difference was sufficient to enable the cows to have a significantly lower mean rectal temperature and respiration rate (38.56 °C, 61.97 breaths/min) than that of the cows housed under normal roofing (39.86 °C; 85.16 breaths/min). The cows housed under modified roofing produced more milk (P < 0.05) but did not differ significantly in reproductive performance from the cows housed under normal roofing. PMID:20887315

Khongdee, Sriapa; Sripoon, Somchai; Chousawai, Somchai; Hinch, Geoff; Chaiyabutr, Narongsak; Markvichitr, Kanjana; Vajrabukka, Chanvit

2010-10-01

43

Thermal Performance Data Services (TPDS)  

NASA Technical Reports Server (NTRS)

Initiated as a NASA Engineering and Safety Center (NESC) assessment in 2009, the Thermal Performance Database (TPDB) was a response to the need for a centralized thermal performance data archive. The assessment was renamed Thermal Performance Data Services (TPDS) in 2012; the undertaking has had two fronts of activity: the development of a repository software application and the collection of historical thermal performance data sets from dispersed sources within the thermal performance community. This assessment has delivered a foundational tool on which additional features should be built to increase efficiency, expand the protection of critical Agency investments, and provide new discipline-advancing work opportunities. This report contains the information from the assessment.

French, Richard T.; Wright, Michael J.

2013-01-01

44

The Rehab Guide: Roofs  

NSDL National Science Digital Library

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, ��as well as protective strategies, energy and air filtration issues, roofing materials, and gutters and downspouts.� 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.

2006-11-17

45

Thermal Performance Benchmarking (Presentation)  

SciTech Connect

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

Moreno, G.

2014-11-01

46

Thermal Performance of Uninsulated and Partially Filled Wall Cavities: Preprint  

SciTech Connect

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

Ridouane, E. H.; Bianchi, M.

2011-08-01

47

Sustainable roofs with real energy savings  

SciTech Connect

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

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

1996-12-31

48

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

NASA Astrophysics Data System (ADS)

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

Liu, Xi; Mijic, Ana; Maksimovic, Cedo

2014-05-01

49

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

SciTech Connect

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

Syd S. Peng

2003-01-15

50

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

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

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

51

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

SciTech Connect

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

Kosny, J.; Christian, J.E.

1996-10-01

52

ROOFING SCIENCE  

Microsoft Academic Search

John E. Bishop wrote this article from his position as a marketing professional with a non-profit organization that has been providing energy saving strategies and technologies to consumers and businesses nationwide since the early 1980's. Winter weather plays havoc on roof systems in WNY. Even with adequate net-free area, moisture problems such as mold, mildew and ice dams persist. Often,

John E. Bishop

53

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)

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.

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

2013-06-01

54

Moisture studies of a self-drying roof: Tests in the large scale climate simulator and results from thermal and hygric models  

SciTech Connect

Simultaneous experiments on the moisture behavior of six low-slope roof systems were performed in a climate simulator. The systems comprised a self-drying design over a conventional metal deck, a self-drying design over a significantly more permeable slotted metal deck and four others over conventional metal decks: a system typical of US construction with a liquid water permeable vapor retarder, a system typical of European construction with a liquid water permeable vapor retarder, a top-ventilated system with a polyethylene vapor retarder, and an impermeable control system with a polyethylene vapor retarder. Total weight of each test panel was measured and recorded continuously, along with temperatures and heat fluxes, to compare the behavior of the various systems. The authors imposed steady-state temperatures from hot summer to cold winter conditions to obtain the R-values of the construction dry insulations in each panel. Temperature cycles typical of hot summer days and mild winter days were then imposed above the construction dry assemblies to obtain baseline diurnal performance. The authors applied a one-dimensional thermal and hygric model. The solid and slotted deck were assumed to differ only in water vapor permeance. A model was not attempted for the top-ventilated system. The 1-D model predicted very well the slow rates of wetting in the winter cycles and both the slow then fast rates of drying in the summer cycles before and after water addition, except it overpredicted the drying rate for the US construction with a liquid water permeable vapor retarder.

Desjarlais, A.O.; Petrie, T.W.; Childs, P.W.; Atchley, J.A.

1998-08-01

55

Development of a Roof Savings Calculator  

SciTech Connect

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

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

2011-01-01

56

Field experience and dew point studies of a retrofitted roof  

SciTech Connect

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.

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

1997-11-01

57

Plant functional traits predict green roof ecosystem services.  

PubMed

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

Lundholm, Jeremy; Tran, Stephanie; Gebert, Luke

2015-02-17

58

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

PubMed Central

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

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

2007-01-01

59

Occupant dynamics in rollover crashes: influence of roof deformation and seat belt performance on probable spinal column injury.  

PubMed

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

Bidez, Martha W; Cochran, John E; King, Dottie; Burke, Donald S

2007-11-01

60

Advanced Energy Efficient Roof System  

Microsoft Academic Search

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

Jane Davidson

2008-01-01

61

Thermal and other tests of photovoltaic modules performed in natural sunlight  

NASA Technical Reports Server (NTRS)

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

Stultz, J. W.

1979-01-01

62

Inclusion of cool roofs in nonresidential Title 24 prescriptive requirements  

SciTech Connect

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

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

2002-12-15

63

Which Roof Is Tops?  

NSDL National Science Digital Library

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

Center For Engineering Educational Outreach

64

Thermal Performance Challenges from Silicon to Systems  

Microsoft Academic Search

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

Ram Viswanath; Vijay Wakharkar; Vassou Lebonheur

2000-01-01

65

Thermal performance testing of the Explorer Platform  

NASA Technical Reports Server (NTRS)

The Explorer Platform (EP) has been designed to accommodate on-orbit payload and bus module changeout via Space Transportation System (STS) servicing. Such a versatile spacecraft platform designed to experience widely different environmental exposures and operational conditions, coupled with program constraints on schedule and budget, presented a challenge to implementing a technically sound thermal vacuum/thermal balance test program. This paper discusses thermal performance tests implemented at the subsystem and system levels, and the risks accepted resulting from test sequence, configuration. and tests omitted from the program. No thermal cycling or thermal balance tests were performed on the integrated spacecraft level, although both the Payload (EUVE) and Platform (EP) received independent testing. The decision to take this approach is discussed with respect to the thermal design and the associated risks taken to maintain budget and schedule.

Wasson, David; Ducas, William; Ousley, Wes

1993-01-01

66

Submission of manuscript to Energy and Buildings A thermal model for Phase Change Materials in a building roof for a  

E-print Network

Submission of manuscript to Energy and Buildings A thermal model for Phase Change Materials: Stéphane GUICHARD Physics and Mathematical Engineering Laboratory for Energy and Environment (PIMENT in "Energy and Buildings 70 (2014) http://www.sciencedirect.com/science/article/pii/ S0378778813007962" DOI

Paris-Sud XI, Université de

67

Thermal performance and heat transport in aquifer thermal energy storage  

NASA Astrophysics Data System (ADS)

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.

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

68

Transmutation Fuel Performance Code Thermal Model Verification  

SciTech Connect

FRAPCON fuel performance code is being modified to be able to model performance of the nuclear fuels of interest to the Global Nuclear Energy Partnership (GNEP). The present report documents the effort for verification of the FRAPCON thermal model. It was found that, with minor modifications, FRAPCON thermal model temperature calculation agrees with that of the commercial software ABAQUS (Version 6.4-4). This report outlines the methodology of the verification, code input, and calculation results.

Gregory K. Miller; Pavel G. Medvedev

2007-09-01

69

Predicting moisture problems in low-slope roofing  

SciTech Connect

Moisture intrusion is the major reason why low-slope roofing systems fail prematurely. With approximately 75% of all roofing activity being reroofing, the roofing professional is faced with deciding what to do with an existing wet roof on almost a daily basis. This paper describes finite-difference computer modeling that has been performed to address moisture control in low-slope roof systems. Based on a large database of finite difference modeling results, algorithms have been developed that allow the roofing practitioners to simply determine if a roofing system design requires a vapor retarder or if the system can be modified to enhance its tolerance for small leaks. This paper illustrates how modeling results were obtained, describes the process employed to develop the algorithms, and demonstrates how these algorithms can be used to design a moisture tolerant low-slope roof. The range of applicability and limitations of these algorithms is also detailed.

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

1998-11-01

70

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

NASA Astrophysics Data System (ADS)

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

Azad, E.

2011-12-01

71

Why Cool Roofs?  

ScienceCinema

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

Chu, Steven

2013-05-29

72

Why Cool Roofs?  

SciTech Connect

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

Chu, Steven

2010-01-01

73

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

NASA Astrophysics Data System (ADS)

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

Shelbaya, Ahmad Adam

74

Specifying, Installing and Maintaining Built-Up and Modified Bitumen Roofing Systems.  

ERIC Educational Resources Information Center

Examines built-up, modified bitumen, and hybrid combinations of the two roofing systems and offers advise on how to assure high- quality performance and durability when using them. Included is a glossary of commercial roofing terms and asphalt roofing resources to aid in making decisions on roofing and systems product selection. (GR)

Hobson, Joseph W.

2000-01-01

75

Condensation Risk of Mechanically Attached Roof Systems in Cold Climate Zones  

SciTech Connect

A white roof, cool roof, is constructed to decrease thermal loads from solar radiation, therefore saving energy by decreasing the cooling demands. Unfortunately, cool roofs with mechanically attached membrane, have shown to have a higher risk of intermediate condensation in the materials below the membrane in certain climates (Ennis & Kehrer, 2011) and in comparisons with similar construction with a darker exterior surface (Bludau, Zirkelbach, & Kuenzel, 2009). As a consequence, questions have been raised regarding the sustainability and reliability of using cool roof membranes in Northern U.S. climate zones. A white roof surface reflects more of the incident solar radiation in comparisons with a dark surface, which makes a distinguished difference on the surface temperature of the roof. However, flat roofs with either a light or dark surface and if facing a clear sky, are constantly losing energy to the sky due to the exchange of infrared radiation. This phenomenon exists both during the night and the day. During the day, if the sun shines on the roof surface, the exchange of infrared radiation typically becomes insignificant. During nights and in cold climates, the temperature difference between the roof surface and the sky can deviate up to 20 C (Hagentoft, 2001) which could result in a very cold surface temperature compared to the ambient temperature. Further, a colder surface temperature of the roof increases the energy loss and the risk of condensation in the building materials below the membrane. In conclusion, both light and dark coated roof membranes are cooled by the infrared radiation exchange during the night, though a darker membrane is more heated by the solar radiation during the day, thus decreasing the risk of condensation. The phenomenon of night time cooling from the sky and the lack of solar gains during the day is not likely the exclusive problem concerning the risk of condensation in cool roofs with mechanically attached membranes. Roof systems with thermoplastic membranes are prone to be more effected by interior air intrusion into the roof construction; both due to the wind induced pressure differences and due to the flexibility and elasticity of the membrane (Molleti, Baskaran, Kalinger, & Beaulieu, 2011). Depending on the air permeability of the material underneath the membrane, wind forces increase the risk of fluttering (also referred as billowing) of the thermoplastic membrane. Expectably, the wind induced pressure differences creates a convective air flow into the construction i.e. Page 2 air intrusion. If the conditions are right, moisture from the exchanging air may condensate on surfaces with a temperature below dew-point. The definite path of convective airflows through the building envelope is usually very difficult to determine and therefore simplified models (K nzel, Zirkelbach, & Scfafaczek, 2011) help to estimate an additional moisture loads as a result of the air intrusion. The wind uplifting pressure in combination with wind gusts are important factors for a fluttering roof. Unfortunately, the effect from a fluctuating wind is difficult to estimate as this is a highly dynamic phenomenon and existing standards (ASTM, 2011a) only take into account a steady state approach i.e. there is no guidance or regulations on how to estimate the air intrusion rate. Obviously, a more detailed knowledge on the hygrothermal performance of mechanically attached cool roof system is requested; in consideration to varying surface colors, roof air tightness, climate zones and indoor moisture supply.

Pallin, Simon B [ORNL

2013-01-01

76

Protected Membrane Roofs: A Sustainable Roofing Solution.  

ERIC Educational Resources Information Center

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

Roodvoets, David L.

2003-01-01

77

Roofing Workbook and Tests: Rigid Roofing.  

ERIC Educational Resources Information Center

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

Klingensmith, Robert, Ed.

78

Thermal performance of the ATST secondary mirror  

NASA Astrophysics Data System (ADS)

The Advanced Technology Solar Telescope (ATST) has a 4.24m off-axis primary mirror designed to deliver diffractionlimited images of the sun. Its baseline secondary mirror (M2) design uses a 0.65m diameter Silicon Carbide mirror mounted kinematically by a bi-pod flexure mechanism at three equally spaced locations. Unlike other common telescopes, the ATST M2 is to be exposed to a significant solar heat loading. A thermal management system (TMS) will be developed to accommodate the solar loading and minimize "mirror seeing effect" by controlling the temperature difference between the M2 optical surface and the ambient air at the site. Thermo-elastic analyses for steady state thermal behaviors of the ATST secondary mirror was performed using finite element analysis by I-DEAS TM and PCRINGE TM for the optical analysis. We examined extensive heat transfer simulation cases and their results were discussed. The goal of this study is to establish thermal models by I-DEAS for an adequate thermal environment. These thermal models will be useful for estimating segment thermal responses. Current study assumes a few sample time dependent thermal loadings to synthesize the operational environment.

Cho, Myung K.; DeVries, Joe; Hansen, Eric

2007-12-01

79

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

NASA Technical Reports Server (NTRS)

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

Boeer, K. W.

1975-01-01

80

Roof bolting equipment & technology  

SciTech Connect

Technology provides an evaluator path to improvement for roof bolting machines. Bucyrus offers three different roof bolts models for various mining conditions. The LRB-15 AR is a single-arm boiler recommended for ranges of 32 inches and above; the dual-arm RB2-52A for ranges of 42 inches and above; and the dual-arm RB2-88A for ranges of 54 inches and above. Design features are discussed in the article. Developments in roof bolting technology by Joy Mining Machinery are reported. 4 photos.

Fiscor, S.

2009-04-15

81

Cool Roof Systems; What is the Condensation Risk?  

SciTech Connect

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

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

2014-01-01

82

A new look at moisture control in low slope roofing  

SciTech Connect

One of the criteria for a moisture-tolerant roof is that moisture accumulation in a roofing system must not be large enough to cause condensation within the roof, since this can damage the insulation and reduce its effectiveness. Failing this criterion would require the inclusion of a vapor retarder into the roofing system. We have tested this requirement using computer simulations for a series of new roofing systems and environmental conditions. This paper uses the database from those simulations to develop a simplified method to predict condensation control using only variables associated with the roof and environmental conditions. This method assesses the potential for condensation within the roof assembly without having to perform a computer simulation. Using the computer simulation output data, the moisture accumulation inside each of the roofing systems was calculated. A critical threshold of moisture accumulation was assigned by analyzing the roofing systems which fail to prevent condensation from occurring within the roofing system. An empirical equation for moisture accumulation as a function of roof system and environmental condition variables is developed. The moisture accumulation calculated using this relationship correlates well with the moisture accumulation based on the results of computer simulations. The ability of these two different relationships for moisture accumulation to predict condensation control using the established critical threshold is assessed. Accuracy of both methods is over 95%.

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

1997-03-01

83

GREEN ROOFS ? A GROWING TREND  

EPA Science Inventory

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

84

Solar power roof shingle  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

85

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.

86

Thermal interface pastes nanostructured for high performance  

NASA Astrophysics Data System (ADS)

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

Lin, Chuangang

87

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

SciTech Connect

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.

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

1997-03-01

88

Application of Spray Foam Insulation Under Plywood and OSB Roof Sheathing (Fact Sheet)  

SciTech Connect

Spray polyurethane foams (SPFs) have advantages over alternative insulation methods because they provide air sealing in complex assemblies, particularly roofs. Spray foam can provide the thermal, air, and vapor control layers in both new and retrofit construction. Unvented roof strategies with open cell and closed cell SPF insulation sprayed to the underside of roof sheathing have been used since the mid-1990s to provide durable and efficient building enclosures. However, there have been isolated incidents of failures (either sheathing rot or SPF delamination) that raise some general concerns about the hygrothermal performance and durability of these systems. The primary risks for roof systems are rainwater leaks, condensation from diffusion and air leakage, and built-in construction moisture. This project directly investigated rain and indirectly investigated built-in construction moisture and vapor drives. Research involved both hygrothermal modeling of a range of rain water leakage scenarios and field evaluations of in-service residential roofs. Other variables considered were climate zone, orientation, interior relative humidity, and the vapor permeance of the coating applied to the interior face of open cell SPF.

Not Available

2013-11-01

89

Carbon sequestration potential of extensive green roofs.  

PubMed

Two studies were conducted with the objective of quantifying the carbon storage potential of extensive green roofs. The first was performed on eight roofs in Michigan and four roofs in Maryland, ranging from 1 to 6 years in age. All 12 green roofs were composed primarily of Sedum species, and substrate depths ranged from 2.5 to 12.7 cm. Aboveground plant material was harvested in the fall of 2006. On average, these roofs stored 162 g C x m(-2) in aboveground biomass. The second study was conducted on a roof in East Lansing, MI. Twenty plots were established on 21 April 2007 with a substrate depth of 6.0 cm. In addition to a substrate only control, the other plots were sown with a single species of Sedum (S. acre, S. album, S. kamtshaticum, or S. spurium). Species and substrate depth represent typical extensive green roofs in the United States. Plant material and substrate were harvested seven times across two growing seasons. Results at the end of the second year showed that aboveground plant material storage varied by species, ranging from 64 g C x m(-2) (S. acre) to 239 g C x m(-2) (S. album), with an average of 168 g C x m(-2). Belowground biomass ranged from 37 g C x m(-2) (S. acre) to 185 g C x m(-2) (S. kamtschaticum) and averaged 107 g C x m(-2). Substrate carbon content averaged 913 g C x m(-2), with no species effect, which represents a sequestration rate of 100 g C x m(-2) over the 2 years of this study. The entire extensive green roof system sequestered 375 g C x m(-2) in above- and belowground biomass and substrate organic matter. PMID:19848177

Getter, Kristin L; Rowe, D Bradley; Robertson, G Philip; Cregg, Bert M; Andresen, Jeffrey A

2009-10-01

90

Thermal Performance of Aircraft Polyurethane Seat Cushions  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

91

Thermal performance of aircraft polyurethane seat cushions  

NASA Technical Reports Server (NTRS)

Measurements were conducted on 7.6 x 7.6 cm samples of polyurethane seat cushion material in a modified National Bureau of Standards smoke density chamber to simulate real life conditions for an onboard aircraft fire or post-crash fire. In this study, a non-flaming heat radiation condition was simulated. Two aluminized polymeric fabrics (Norfab 11HT-26-A and Preox 1100-4) and one neoprene type material in two thicknesses (Vonar 2 and 3) were tested as heat blocking layers to protect the urethane foam from rapid heat degradation. Thermogravimetric analysis and differential scanning calorimetry were performed to characterize thermally the materials tested. It was found that Vonar 2 or 3 provided approximately equal thermal protection to F.R. urethane as the aluminized fabrics, but at a significant weight penalty. The efficiency of the foams to absorb heat per unit mass loss when protected with the heat blocking layer decreases in the heating range of 2.5-5.0 W/sq cm, but remains unchanged or slightly increases in the range of 5.0-7.5 W/sq cm. The results show that at all heat flux ranges tested the usage of a heat blocking layer in aircraft seats significantly improves their thermal performance.

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

1982-01-01

92

Fourier analysis of conductive heat transfer for glazed roofing materials  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

93

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

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

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

94

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

95

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

96

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

97

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

98

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

99

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

100

Photovoltaic roofing tile systems  

NASA Astrophysics Data System (ADS)

The integration of photovoltaic (PV) systems in architecture is discussed. A PV-solar roofing tile system with polymer concrete base; PV-roofing tile with elastomer frame profiles and aluminum profile frames; contact technique; and solar cell modules measuring technique are described. Field tests at several places were conducted on the solar generator, electric current behavior, battery station, electric installation, power conditioner, solar measuring system with magnetic bubble memory technique, data transmission via telephone modems, and data processing system. The very favorable response to the PV-compact system proves the commercial possibilities of photovoltaic integration in architecture.

Melchior, B.

101

THERMAL PERFORMANCE ANALYSIS FOR WSB DRUM  

SciTech Connect

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

Lee, S

2008-06-26

102

Green Roofs for Stormwater Runoff Control  

EPA Science Inventory

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

103

Green Roofs for Stormwater Runoff Control - Abstract  

EPA Science Inventory

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

104

ACCESS: Thermal Mechanical Design, Performance, and Status  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

105

Thermal Performance of the XRS Helium Insert  

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

106

Roof insulation support system  

Microsoft Academic Search

A roof insulator support system includes a plurality of longitudinally extending beams supporting a plurality of regularly spaced, laterally extending purlins of Z-shaped cross section with an upturned lip portion on the lower flange of each purlin. Elongated liner support members, being extrusions of a generally inverted T-shape, are attached to and extend along the bottom of each purlin. Each

L. J. Fischer; T. J. McNellis

1977-01-01

107

High-Tech Roof Management.  

ERIC Educational Resources Information Center

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

Benzie, Tim

1997-01-01

108

Performance of thermal adhesives in forced convection  

NASA Technical Reports Server (NTRS)

Cooling is critical for the life and performance of electronic equipment. In most cases cooling may be achieved by natural convection but forced convection may be necessary for high wattage applications. Use of conventional type heat sinks may not be feasible from the viewpoint of specific applications and the costs involved. In a heat sink, fins can be attached to the well by ultrasonic welding, by soldering, or with a number of industrially available thermal adhesives. In this paper, the author investigates the heat transfer characteristics of several adhesives and compares them with ultrasonic welding and theoretically calculated values. This experiment was conducted in an air flow chamber. Heat was generated by using heaters mounted on the well. Thermstrate foil, Uniset A401, and Aremco 571 adhesives were tested along with an ultrasonically welded sample. Ultrasonic welding performed far better than the adhesives and Thermstrate foil. This type of experiment can be adapted for a laboratory exercise in an upper level heat transfer course. It gives students an exposure to industrial applications that help them appreciate the importance of the course material.

Kundu, Nikhil K.

1993-01-01

109

Thermal performance of the Brookhaven natural thermal storage house  

SciTech Connect

In the Brookhaven natural thermal storage house, an energy-efficient envelope, passive solar collectors, and a variety of energy conservation methods are incorporated. The thermal characteristics of the house during the tested heating season are evaluated. Temperature distributions at different zones are displayed, and the effects of extending heating supply ducts only to the main floor and heating return ducts only from the second floor are discussed. The thermal retrievals from the structure and the passive collectors are assessed, and the total conservation and passive solar contributions are outlined. Several correlation factors relating these thermal behaviors are introduced, and their diurnal variations are displayed. Finally, the annual energy requirements, and the average load factors are analyzed and discussed.

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

1981-01-01

110

WMAP Observatory Thermal Design and On-Orbit Thermal Performance  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

111

Thermal Performance Testing Of Cryogenic Piping Systems  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

112

Thermal Performance of the LDX Floating Coil  

NASA Astrophysics Data System (ADS)

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

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

2006-04-01

113

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

SciTech Connect

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

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

1998-07-01

114

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

SciTech Connect

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

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

2013-04-01

115

TASK 2.5.7 FIELD EXPERIMENTS TO EVALUATE COOL-COLORED ROOFING  

SciTech Connect

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

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

2010-03-01

116

40. Inside condenser building, steel roof trusses and channeliron roof ...  

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

40. Inside condenser building, steel roof trusses and channel-iron roof perlins at top, northern end of crane beam and carriage at bottom, north oblique view, east wall and center partition wall - Sewall's Falls Hydroelectric Facility, East end of Second Street spanning Merrimack River, Concord, Merrimack County, NH

117

Photovoltaic Roof Heat Flux  

NASA Astrophysics Data System (ADS)

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.

Samady, Mezhgan Frishta

118

Performance of a solar-thermal collector  

NASA Technical Reports Server (NTRS)

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

Higa, W. H.

1975-01-01

119

Development of a Roof Savings Calculator  

SciTech Connect

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

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

2011-01-01

120

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2014 CFR

...Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY...strata, opening dimensions and roof stresses; or (2) Tests which show the...strata, opening dimensions and roof stresses as the area where the roof bolts...

2014-07-01

121

Energy saving potential of various roof technologies  

E-print Network

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

Ray, Stephen D. (Stephen Douglas)

2010-01-01

122

THERMAL INTERRUPTION PERFORMANCE AND FLUCTUATIONS IN HIGH VOLTAGE GAS CIRCUIT  

E-print Network

THERMAL INTERRUPTION PERFORMANCE AND FLUCTUATIONS IN HIGH VOLTAGE GAS CIRCUIT BREAKERS Nils P the thermal interruption capability of high voltage self-blast gas circuit breakers1 . In parallel that nozzle ablation leads to systematic performance degradation. The influence of nozzle ablation on various

Basse, Nils Plesner

123

How Cool Is Your Roof?  

ERIC Educational Resources Information Center

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

Fickes, Michael

2001-01-01

124

Passive solar roof ice melter  

Microsoft Academic Search

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

Deutz

1981-01-01

125

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

NASA Technical Reports Server (NTRS)

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

McMillan, Vernotto C.

1998-01-01

126

Measuring mine roof bolt strains  

DOEpatents

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

Steblay, Bernard J. (Lakewood, CO)

1986-01-01

127

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

PubMed

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

Ge, Zhiwei; Ye, Feng; Ding, Yulong

2014-05-01

128

Investigation of Fundamental Modeling and Thermal Performance Issues for a Metallic Thermal Protection System Design  

NASA Technical Reports Server (NTRS)

A study was performed to develop an understanding of the key factors that govern the performance of metallic thermal protection systems for reusable launch vehicles. A current advanced metallic thermal protection system (TPS) concept was systematically analyzed to discover the most important factors governing the thermal performance of metallic TPS. A large number of relevant factors that influence the thermal analysis and thermal performance of metallic TPS were identified and quantified. Detailed finite element models were developed for predicting the thermal performance of design variations of the advanced metallic TPS concept mounted on a simple, unstiffened structure. The computational models were also used, in an automated iterative procedure, for sizing the metallic TPS to maintain the structure below a specified temperature limit. A statistical sensitivity analysis method, based on orthogonal matrix techniques used in robust design, was used to quantify and rank the relative importance of the various modeling and design factors considered in this study. Results of the study indicate that radiation, even in small gaps between panels, can reduce significantly the thermal performance of metallic TPS, so that gaps should be eliminated by design if possible. Thermal performance was also shown to be sensitive to several analytical assumptions that should be chosen carefully. One of the factors that was found to have the greatest effect on thermal performance is the heat capacity of the underlying structure. Therefore the structure and TPS should be designed concurrently.

Blosser, Max L.

2002-01-01

129

Effects of Solar Photovoltaic Panels on Roof Heat Transfer  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

130

Electrical and thermal performance of PWB transformers  

Microsoft Academic Search

The authors use analytical tools developed to predict the high-frequency characteristics of conventionally wound transformers and apply them to the planar printed wiring board (PWB) transformer case. The authors present a simple modeling technique that is useful in calculating the temperature rise for a PWB transformer assuming conduction through the base of the device as the only thermal path. These

Mahmoud P. Sayani; G. R. Skutt; P. S. Venkatraman

1991-01-01

131

Thermal aspects of high performance packaging with synthetic diamond  

SciTech Connect

The extraordinary thermal conductivity and dielectric properties of diamond translate into performance and reliability advantages for electronic packaging of high performance semiconductors. Demonstrated diamond substrate Pin Grid Array (PGA) packages and Multi Chip-Modules (MCM) have changed the whole approach to high performance computing. Subnanosecond computer performance is made possible for the first time by a diamond substrate 3-D architecture.

Boudreaux, P.J. [Lab. for Physical Sciences, College Park, MD (United States)

1995-12-31

132

Advanced Low Conductivity Thermal Barrier Coatings: Performance and Future Directions  

NASA Technical Reports Server (NTRS)

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.

Zhu, Dongming; Miller, Robert A.

2008-01-01

133

Thermal Performance of an Annealed Pyrolytic Graphite Solar Collector  

NASA Technical Reports Server (NTRS)

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

Jaworske, Donald A.; Hornacek, Jennifer

2002-01-01

134

Feasibility of determining flat roof heat losses using aerial thermography  

NASA Technical Reports Server (NTRS)

The utility of aerial thermography for determining rooftop heat losses was investigated experimentally using several completely instrumented test roofs with known thermal resistances. Actual rooftop heat losses were obtained both from in-situ instrumentation and aerial thermography obtained from overflights at an altitude of 305 m. In general, the remotely determined roof surface temperatures agreed very well with those obtained from ground measurements. The roof heat losses calculated using the remotely determined roof temperature agreed to within 17% of those calculated from 1/R delta T using ground measurements. However, this agreement may be fortuitous since the convective component of the heat loss is sensitive to small changes in roof temperature and to the average heat transfer coefficient used, whereas the radiative component is less sensitive. This, at this time, it is felt that an acceptable quantitative determination of roof heat losses using aerial thermography is only feasible when the convective term is accurately known or minimized. The sensitivity of the heat loss determination to environmental conditions was also evaluated. The analysis showed that the most reliable quantitative heat loss determinations can probably be obtained from aerial thermography taken under conditions of total cloud cover with low wind speeds and at low ambient temperatures.

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

1979-01-01

135

Thermal management system for high performance PowerPCTM microprocessors  

Microsoft Academic Search

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

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

1997-01-01

136

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

PubMed

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

Vijayaraghavan, K; Joshi, Umid Man

2014-11-01

137

Thermal deformation impacts on SOG Fresnel lens performance  

NASA Astrophysics Data System (ADS)

Silicone-on-Glass (SOG) Fresnel lenses are flat optical elements used in concentrator photovoltaics (CPV). SOG lens production process broadly involves forming optical silicone prisms attached to glass. Silicone is first compressed onto glass while heat is applied in order to shorten its curing time. During the cooling process, however, difference between thermal expansion coefficient for silicon and glass causes thermal deformation of prisms which results in compromised optical efficiency. In this study, thermal-induced deformation of SOG Fresnel lens prisms is analyzed by Surface Profile Measurement (SPM) and Finite Element Analysis (FEA) methods. In order to better observe patterns of thermal deformation and overall lens performance, lens samples were subjected to an optical efficiency test. Focus quality (FQ) images were also taken and observed in order to further analyze thermally affected lens performance. The study is expected to contribute to knowledge on temperature induced performance determinants of SOG Fresnel lenses.

Büyükco?kun, Murat; Annen, Hans Philipp; González Muñoz, Luis Felipe

2012-10-01

138

Thermal performance of concrete masonry unit wall systems  

SciTech Connect

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

Kosny, J.

1995-12-31

139

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

ERIC Educational Resources Information Center

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

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

140

Improving the thermal performance of the US residential window stock  

Microsoft Academic Search

Windows have typically been the least efficient thermal component in the residential envelope, but technology advances over the past decade have helped to dramatically improve the energy efficiency of window products. While the thermal performance of these advanced technology windows can be easily characterized for a particular building application, few precise estimates exist of their aggregate impact on national or

R. E. Brown; D. K. Arasteh; J. H. Eto

1992-01-01

141

The effect of thermal barrier coatings on diesel engine performance  

Microsoft Academic Search

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

T. Hejwowski; A. Wero?ski

2002-01-01

142

Dynamic Thermal Management for High-Performance Microprocessors  

Microsoft Academic Search

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

David Brooks; Margaret Martonosi

2001-01-01

143

Thermal performance of an elliptical pin fin heat sink  

Microsoft Academic Search

Comparative thermal tests have been carried out using, aluminum heat sinks made with extruded fin, cross-cut rectangular pins, and elliptical shaped pins in low air flow environments. The elliptical pin heat sink was designed to minimize the pressure loss across the heat sink by reducing the vortex effects and to enhance the thermal performance by maintaining large exposed surface area

Christopher L. Chapman; Seri Lee; Bill L. Schmidt

1994-01-01

144

Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

145

The thermal dependence of fast-start performance in fish  

Microsoft Academic Search

Many fish species use fast-starts to escape predators and capture prey. There is evidence for changes in fast-start behaviour with temperature, over acute, seasonal, developmental and evolutionary time scales. Maximum velocity often increases with acute temperature changes. Thermal acclimation can improve fast-start performance, although responses appear to be reduced in more eurythermal species. Changes in performance with thermal acclimation are

Genevieve K. Temple; Ian A. Johnston

1997-01-01

146

Evaluation of VOC emissions from heated roofing asphalt. Final report  

SciTech Connect

The report gives results of a short-term in-house project to characterize emissions from a simulated asphalt roofing kettle, performed at EPA/AEERL. Hot asphalt surfacing and resurfacing has been identified as a possible significant source of volatile organic compound (VOC) emissions that may affect human health and contribute to the ozone non-attainment problem. The purpose of the study was to collect, identify, and semi-quantitate as many compounds as possible that are discharged during the open heating of roofing asphalt and relate them to the amount volatilized into the air. Types 1, 2, and 3 mopping grade asphalts were chosen for the study. They constitute more than 90% of roofing asphalt used. Samples of each type of asphalt were placed in a simulated roofing kettle, heated to predetermined temperatures, and sampled for volatile and semi-volatile organic emissions. Compounds identified during the study were alkanes, aromatics, a ketone, and an aldehyde.

Kariher, P.; Tufts, M.; Hamel, L.

1991-11-01

147

Thermal Components Boost Performance of HVAC Systems  

NASA Technical Reports Server (NTRS)

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

2012-01-01

148

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

149

Space Shuttle Orbiter leading edge structural subsystem thermal performance  

NASA Technical Reports Server (NTRS)

An extensive qualification test program and the STS-1 flight of the Space Shuttle Orbiter have provided the data necessary to verify the performance of the Orbiter thermal protection system. The reinforced carbon-carbon leading edge structural subsystem is used on areas of the orbiter where temperatures exceed 2300 F. The subsystem consists of the ROC nose cap and wing leading edge panels, metallic attachments, internal insulation, and interface tiles. Thermal response data from the qualification tests and the STS-1 flight, postflight inspection, and analytical predictions support the conclusion that the thermal performance of the subsystem verified the design.

Curry, D. M.; Cunningham, J. A.; Frahm, J. R.

1982-01-01

150

Analysis of Wind Forces on RoofTop Solar Panel  

Microsoft Academic Search

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

Yogendra Panta; Ganesh Kudav

2011-01-01

151

Eco-Environmental Factors in Green Roof Application in Indian Cities  

NASA Astrophysics Data System (ADS)

Green-roof is the cost-effective environmental mitigation strategy for urban areas [1]. Its application is limited in India primarily due to inadequate understanding about its cost-benefit analysis and technicalities of its maintenance. Increasing awareness about green roof can alter conservative attitude towards its application. So, this work presents a quantified study on green-roof types, cost and environmental benefits while considering different geo-urban climate scenarios for cities of Kolkata, Mumbai, Chennai and New Delhi. Cost estimation for extensive and intensive green-roof with reference to commonly used roof in urban India is also worked out. Attributes considered for environmental discussion are energy savings related to thermal heat gain through roof, roof-top storm-water drainage and sound attenuation. The comparative study confirms that further focused study on individual cities would identify city-specific objectives for green-roof application; strategies like awareness, capacity building programmes, incentives, demonstration projects etc. can be worked out accordingly for wider application of green-roof in Indian cities.

Mukherjee, M.

2014-09-01

152

High Performance Thermal Imaging Using Quantum Well Infrared Photodetector Arrays  

Microsoft Academic Search

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%,

Harald Schneider

2007-01-01

153

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

Microsoft Academic Search

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

S. Cristina; A. Orlandi

1991-01-01

154

Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

155

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

SciTech Connect

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

Miller, William A [ORNL

2006-01-01

156

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

SciTech Connect

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

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

2011-01-01

157

Dynamic Thermal Management for High-Performance Storage Systems  

SciTech Connect

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.

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

2012-01-01

158

Development of a Green Roof Environmental Monitoring and Meteorological Network in New York City  

PubMed Central

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

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

2009-01-01

159

Feasibility and Performance of the Microwave Thermal Rocket Launcher  

NASA Astrophysics Data System (ADS)

Beamed-energy launch concepts employing a microwave thermal thruster are feasible in principle, and microwave sources of sufficient power to launch tons into LEO already exist. Microwave thermal thrusters operate on an analogous principle to nuclear thermal thrusters, which have experimentally demonstrated specific impulses exceeding 850 seconds. Assuming such performance, simple application of the rocket equation suggests that payload fractions of 10% are possible for a single stage to orbit (SSTO) microwave thermal rocket. We present an SSTO concept employing a scaled X-33 aeroshell. The flat aeroshell underside is covered by a thin-layer microwave absorbent heat-exchanger that forms part of the thruster. During ascent, the heat-exchanger faces the microwave beam. A simple ascent trajectory analysis incorporating X-33 aerodynamic data predicts a 10% payload fraction for a 1 ton craft of this type. In contrast, the Saturn V had 3 non-reusable stages and achieved a payload fraction of 4%.

Parkin, Kevin L. G.; Culick, Fred E. C.

2004-03-01

160

Portable Life Support Subsystem Thermal Hydraulic Performance Analysis  

NASA Technical Reports Server (NTRS)

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

Barnes, Bruce; Pinckney, John; Conger, Bruce

2010-01-01

161

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

NASA Astrophysics Data System (ADS)

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

Zhu, Fanglong; Ma, Suqin; Zhang, Weiyuan

2008-05-01

162

Review of End-of-Life Thermal Control Coating Performance  

NASA Technical Reports Server (NTRS)

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

Jaworske, Donald A.; Kline, Sara E.

2008-01-01

163

Permeable Pavements, Green Roofs, and Cisterns  

E-print Network

Permeable Pavements, Green Roofs, and Cisterns Stormwater Treatment Practices for Low site planning and engineer- pavements, green roofs, and cisterns, are ing to reduce or prevent cooperating. #12;Permeable Pavements What are they? Permeable pavements provide alternatives to standard

Hunt, William F.

164

IDENTIFYING ROOF FALL PREDICTORS USING FUZZY CLASSIFICATION  

SciTech Connect

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

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

2010-02-22

165

Integrated heat pipe-thermal storage system performance evaluation  

NASA Astrophysics Data System (ADS)

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.

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

166

Common Roofing and Waterproofing Materials and Equipment. Roofing Workbook and Tests.  

ERIC Educational Resources Information Center

This publication on common roofing and waterproofing materials and equipment is one of a series of units of instruction for roofing apprenticeship classes. The workbook portion is divided into eight topics: production of bitumens and asphalt roofing materials, built-up materials and adhesives, asphalt products and rigid roofing materials,…

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

167

Roofing: Workbook and Tests. Common Roofing and Waterproofing Materials and Equipment.  

ERIC Educational Resources Information Center

This workbook on materials and equipment is one of a series of nine individual units of instruction for roofing apprenticeship classes in California. The workbook covers eight topics: production of bitumens and asphaltic roofing materials; built-up roofing materials and adhesives; asphaltic products and rigid roofing materials; elastomeric and…

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

168

Thermal performance of a customized multilayer insulation (MLI)  

Microsoft Academic Search

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

K. E. Leonhard

1976-01-01

169

Performance of the LDCM Thermal Infrared Sensor for Evapotranspiration Measurement  

NASA Astrophysics Data System (ADS)

Evapotranspiration (ET) rate measurements are being made at the scale of individual farm fields with data from the Landsat satellites. A new instrument, the Thermal Infrared Sensor (TIRS), has been built and tested for launch aboard the next Landsat satellite, the Landsat Data Continuity Mission (LDCM), scheduled for launch on February 11, 2013. TIRS performance requirements were specified to ensure that the LDCM will provide the thermal infrared data necessary to continue measuring field scale ET rates. The presentation will compare the prelaunch performance of TIRS to specifications and to requirements for ET rate measurements. The comparisons will be made in terms of noise equivalent change in radiance and temperature, cross-track uniformity of spectral and radiometric response, spatial resolution and sharpness, and other specified characteristics. Performance was measured while TIRS was operated in a thermal vacuum chamber to simulate the space environment and while illuminated by a calibrated source of thermal infrared radiation. Results indicate that TIRS will perform better than earlier Landsat sensors with respect to radiometric requirements for accurately measuring ET rates.

Irons, J. R.; Reuter, D. C.; Thome, K. J.; Smith, R. L.; Montanaro, M.

2012-12-01

170

Thermal Conduction Module: A High-Performance Multilayer Ceramic Package  

Microsoft Academic Search

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

A. J. Blodgett; D. R. Barbour

1982-01-01

171

The effect of thermal barrier coatings on diesel engine performance  

Microsoft Academic Search

Ceramic coatings hold significant promise in the reduction of wear and abrasion failure in reciprocating and rotary engines for transportation and stationary power. They also have application as thermal barriers to improve the efficiency of the engines, by reducing energy loss and cooling requirements. In this study, the effects of ceramic coating on the performance of the diesel engine were

Imdat Taymaz

2007-01-01

172

Performance evaluation of solar photovoltaic\\/thermal systems  

Microsoft Academic Search

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

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

2001-01-01

173

Thermal performance of multilayer insulation around a horizontal cylinder  

NASA Astrophysics Data System (ADS)

Thermal performance of multiplayer insulation (MLI) is affected by contact pressure between adjacent layers. In order to evaluate the thermal performance of the MLI fabricated in the horizontal cryostats of superconducting magnets, it is important to investigate the contact pressure in the MLI. In case of a horizontal cryostat, the MLI is wound around horizontal cylindrical surface and is compressed at the upper part of the cylinder due to the MLI self-weight. At first, a single thin film wound around the horizontal cylinder was analyzed to evaluate the contact pressure acting on the cylinder. The analysis has been extended to the multiply wound film around horizontal cylinder, in order to investigate the distribution of contact pressure between adjacent layers. By using experimental data obtained with a flat panel calorimeter, the results of this analysis have been applied to evaluate the thermal performance of MLI around a horizontal cylinder. And the non-dimensional contact pressure parameter P? has been introduced as a useful parameter to evaluate and compare the thermal performance among different kinds of MLI.

Ohmori, T.

2005-12-01

174

Heat loss from pitched roofs  

Microsoft Academic Search

In the calculation of heat loss from a pitched roof it is usual to disregard gable areas, insulation location, loft space ventilation and air leakage from the dwelling, as advocated by the CIBSE. The CIBSE method does assume a general loss due to infiltration, but not specifically through the loft. In this paper the problem is analysed by considering steady-state

G. S. Saluja

1986-01-01

175

Passive solar roof ice melter  

SciTech Connect

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.

Deutz, R.T.

1981-09-29

176

Solar Roof Cooling by Evaporation  

E-print Network

Evaporation is nature's way of cooling. By spraying a light film of water in the form of a mist for thirty seconds, then turning the sprays off for five minutes while evaporation takes place, the roof temperature can be reduced from 1650o to 880o...

Patterson, G. V.

1980-01-01

177

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2013 CFR

...Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator...the strata. (4) In each roof bolting cycle, the actual torque or tension of the...bolt installed during each roof bolting cycle shall be tested during or...

2013-07-01

178

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2011 CFR

...Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator...the strata. (4) In each roof bolting cycle, the actual torque or tension of the...bolt installed during each roof bolting cycle shall be tested during or...

2011-07-01

179

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2012 CFR

...Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator...the strata. (4) In each roof bolting cycle, the actual torque or tension of the...bolt installed during each roof bolting cycle shall be tested during or...

2012-07-01

180

SOLAR ROOF POWERS THE NJIT CAMPUS CENTER  

E-print Network

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

Bieber, Michael

181

Seismic qualification of building roof structure  

Microsoft Academic Search

This paper presents a method for qualifying the existing roof structure of the Fuels and Materials Examination Facility (FMEF) at the US Department of Energy's Hanford Site in Richland, Washington. The roof is a safety class 1 structure and subject to the design-basis earthquake (DBE). The roof consists of 26 prestressed concrete T-beams 82 feet long spaced 6 feet on

M. A. Islam; R. B. Pan

1991-01-01

182

Comparison of Software Models for Energy Savings from Cool Roofs  

SciTech Connect

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

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

2014-01-01

183

Thermal Performance Impacts of Center-of-Glass Deflections in Installed Insulating  

E-print Network

LBNL-5800E Thermal Performance Impacts of Center-of- Glass Deflections in Installed Insulating: temperature difference Thermal Performance Impacts of Center-of-Glass Deflections in Installed Insulating on performance. Key words: Insulating glass unit; U-factor; thermal transmittance; thermal performance

184

A Roof for ALMA  

NASA Astrophysics Data System (ADS)

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

2007-03-01

185

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

SciTech Connect

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

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

2004-07-01

186

Thermal Insulation Performance in the Process Industries: Facts and Fallacies  

E-print Network

Measurement of Insulations," Ed. R.P. !ye, STP 660, American Society of Testing and Materials, Philadelphia, PA, December, 1978. 8. "Thermal Insulation Performance," Eds. D.L. McElroy and R.P. Tye, STP 718, American Society of Testing and Materials..., Philadelphia, PA, December, 1930. 9. "Thermal Insulation, Materials, and Systems for Energy Conservation in the '80' s," Eds. P.A. Govan, D.M. Greason, and J.D. McAllister STP 789, American Society of Testing and Materials, Philadelphia, PA, January, 1983...

Tye, R. P.

187

Design and performance of Skylab thermal/environmental control system  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

188

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

189

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

190

Thermal Performance of the LHC Short Straight Section Cryostat  

E-print Network

The LHC Short Straight Section (SSS) cryostat houses and thermally protects in vacuum the cold mass which contains a twin-aperture superconducting quadrupole magnet and superconducting corrector magnets operating at 1.9 K in superfluid helium. In addition to mechanical requirements, the cryostat is designed to minimize the heat in-leak from the ambient temperature to the cold mass. Mechanical components linking the cold mass to the vacuum vessel such as support posts and an insulation vacuum barrier are designed to have minimum heat conductivity with efficient thermalisations for heat interception. Heat in-leak by radiation is reduced by employing multilayer insulation wrapped around the cold mass and an actively cooled aluminium thermal shield. The recent commissioning and operation of two SSS prototypes in the LHC Test String 2 have given a first experimental validation of the thermal performance of the SSS cryostat in nominal operating conditions. Temperature sensors mounted in critical locations provide a...

Bergot, J B; Nielsen, L; Parma, Vittorio; Rohmig, P; Roy, E

2002-01-01

191

Impact of different backgrounds on thermal infrared IDS performance  

SciTech Connect

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

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

1993-12-31

192

Thermal shock performance of CVD tungsten coating at elevated temperatures  

NASA Astrophysics Data System (ADS)

Thick tungsten coating was produced by chemical vapour deposition (CVD) at a high deposition rate 0.6 mm/h. High heat flux tests using electron beam were performed to evaluate the thermal shock resistance of the developed CVD tungsten coating. The polished CVD tungsten surfaces were exposed to single shot disruption-like and repetitive ELM-like thermal shock loads at various temperatures and absorbed power densities. The thermal shock-induced damages were analysed by surface roughometer, scanning electron microscopy and light microscopy. Damage characteristics of the CVD tungsten were compared to that of the reference hot-rolled pure tungsten. The cracking thresholds and damage mechanisms of the CVD tungsten were presented and discussed. The tested results show that specific columnar grain structure of the CVD tungsten and base temperatures have significant influence on the crack formation and propagation direction towards the bulk material.

Lian, Youyun; Liu, Xiang; Cheng, Zhengkui; Wang, Jin; Song, Jiupeng; Yu, Yang; Chen, Jiming

2014-12-01

193

Thermal performance of phase change wallboard for residential cooling application  

SciTech Connect

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.

Feustel, H.E.; Stetiu, C.

1997-04-01

194

Thermal performance of various multilayer insulation systems below 80K  

SciTech Connect

The SSC collider dipole cryostat consists of a vacuum shell operating at room temperature, two thermal shields operating near 80K and 20K respectively, and the superconducting magnet assembly operating near 4K. The cryostat design incorporates multilayer insulation (MLI) blankets to limit radiant heat transfer into the 80K and 20K thermal shields. Also, an MLI blanket is used to impede heat transfer through residual gas conduction into the 4K superconducting magnet assembly. A measurement facility at Fermilab has been used to experimentally optimize the thermal insulation system for the dipole cryostat. Previous thermal measurements have been used to define the 80K MLI system configuration and verify system performance. With the 80K MLI system defined, the current effort has focused on experimentally defining the optimum insulation scheme for the 20K thermal shield. The SSC design specification requires that radiant heat transfer be limited to 0.093 W/m[sup 2] at an insulating vacuum of 10[sup [minus]6]torr.

Boroski, W.N.; Nicol, T.H.; Schoo, C.J.

1992-04-01

195

Thermal performance of various multilayer insulation systems below 80K  

SciTech Connect

The SSC collider dipole cryostat consists of a vacuum shell operating at room temperature, two thermal shields operating near 80K and 20K respectively, and the superconducting magnet assembly operating near 4K. The cryostat design incorporates multilayer insulation (MLI) blankets to limit radiant heat transfer into the 80K and 20K thermal shields. Also, an MLI blanket is used to impede heat transfer through residual gas conduction into the 4K superconducting magnet assembly. A measurement facility at Fermilab has been used to experimentally optimize the thermal insulation system for the dipole cryostat. Previous thermal measurements have been used to define the 80K MLI system configuration and verify system performance. With the 80K MLI system defined, the current effort has focused on experimentally defining the optimum insulation scheme for the 20K thermal shield. The SSC design specification requires that radiant heat transfer be limited to 0.093 W/m{sup 2} at an insulating vacuum of 10{sup {minus}6}torr.

Boroski, W.N.; Nicol, T.H.; Schoo, C.J.

1992-04-01

196

Thermal Performance Testing of Glass Microspheres under Cryogenic Vacuum Conditions  

NASA Astrophysics Data System (ADS)

A key element of space launch vehicles and systems is thermal insulation for cryogenic tanks and piping. Glass microspheres, or glass bubbles, represent an alternative insulation material for a number of applications. Composite materials and engineered thermal insulation systems are also being developed based on the use of glass bubbles as the main constituent material. Commonly used materials, such as spray-on foam insulation, or SOFI, for vehicle tanks and perlite powder for ground storage tanks, are targeted for replacement with the new-technology systems that use glass bubbles. Complete thermal characterization of the glass bubbles is the first step toward producing the engineering solutions required for the energy-efficient, low-maintenance cryogenic systems of the future. Thermal performance testing of the glass microsphere material was successfully completed at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The test measurements were made at the full temperature difference (typical boundary temperatures of 78 kelvin [K] and 293 K) and included the full cold-vacuum pressure range. The results are reported in apparent thermal conductivity (k-value) and mean heat flux.

Fesmire, J. E.; Augustynowicz, S. D.

2004-06-01

197

Thermal performance of a customized multilayer insulation (MLI)  

NASA Technical Reports Server (NTRS)

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

Leonhard, K. E.

1976-01-01

198

Asphalt roofing industry Fourier transform infrared spectroscopy modified bitumen  

SciTech Connect

A Request for Emissions Testing at Four Asphalt Roofing and Processing Facilities was submitted by the US EPA Emission Standards Division (ESD), Minerals and Inorganic Chemicals Group (MICG) to the Emission Measurement Center (EMC). The Emission Measurement Center directed Midwest Research Institute (MRI) to conduct emissions testing at asphalt roofing plants. This report presents results of MRI`s FTIR and Method 25A testing conducted at US Intec in Port Arthur, Texas. The field measurements were performed in September 1997 under several test conditions for both controlled and uncontrolled emissions.

NONE

1999-07-01

199

Thermal and aerothermal performance of a titanium multiwall thermal protection system  

NASA Technical Reports Server (NTRS)

A metallic thermal protection system (TPS) concept the multiwall designed for temperature and pressure at Shuttle body point 3140 where the maximum surface temperature is approximately 811 K was tested to evaluate thermal performance and structural integrity. A two tile model of titanium multiwall and a model consisting of a low temperature reusable surface insulation (LRSI) tiles were exposed to 25 simulated thermal and pressure Shuttle entry missions. The two systems performed the same, and neither system deteriorated during the tests. It is indicated that redesign of the multiwall tiles reduces tile thickness and/or weight. A nine tile model of titanium multiwal was tested for radiant heating and aerothermodynamics. Minor design changes that improve structural integrity without having a significant impact on the thermal protection ability of the titanium multiwall TPS are identified. The capability of a titanium multiwall thermal protection system to protect an aluminum surface during a Shuttle type entry trajectory at locations on the vehicle where the maximum surface temperature is below 811 K is demonstrated.

Avery, D. E.; Shideler, J. L.; Stuckey, R. N.

1981-01-01

200

Moisture design to improve durability of low-slope roofing systems  

SciTech Connect

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.

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

1996-12-31

201

A Measurement Method of Actual Thermal Performance of Detached Houses  

E-print Network

-cx [ ] Continuous-cx Glossary check: [ ] yes [ X ] no MQC task: [ ] Program [ ] Design [ ] Elaboration [ X ] Realization [ X ] Operation A DEVELOPMENT OF CX TOOLS FOR HVAC SYSTEM IN RESIDENCE A MEASUREMENT METHOD OF ACTUAL THERMAL PERFORMANCE... of Engineering, Mie University 1515 Kamihama-cho, Tsu, Japan 514-8507 Hisashi MIURA Graduate School of Kyoto University, Yoshida-Honmachi, Sakyou-ku, Kyoto, Japan 606-8501 1. Introduction This paper describes the measuring method of actualthermal...

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

2004-01-01

202

Life sciences passive GN2 freezer thermal performance test  

NASA Technical Reports Server (NTRS)

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

Belshaw, G. W.

1981-01-01

203

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...

204

EVALUATION OF VOC EMISSIONS FROM HEATED ROOFING ASPHALT  

EPA Science Inventory

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

205

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

206

Demonstration of energy savings of cool roofs  

SciTech Connect

Dark roofs raise the summertime air-conditioning demand of buildings. For highly-absorptive roofs, the difference between the surface and ambient air temperatures can be as high as 90 F, while for highly-reflective roofs with similar insulative properties, the difference is only about 20 F. For this reason, cool roofs are effective in reducing cooling energy use. Several experiments on individual residential buildings in California and Florida show that coating roofs white reduces summertime average daily air-conditioning electricity use from 2--63%. This demonstration project was carried out to address some of the practical issues regarding the implementation of reflective roofs in a few commercial buildings. The authors monitored air-conditioning electricity use, roof surface temperature, plenum, indoor, and outdoor air temperatures, and other environmental variables in three buildings in California: two medical office buildings in Gilroy and Davis and a retail store in San Jose. Coating the roofs of these buildings with a reflective coating increased the roof albedo from an average of 0.20--0.60. The roof surface temperature on hot sunny summer afternoons fell from 175 F--120 F after the coating was applied. Summertime average daily air-conditioning electricity use was reduced by 18% (6.3 kWh/1000ft{sup 2}) in the Davis building, 13% (3.6 kWh/1000ft{sup 2}) in the Gilroy building, and 2% (0.4 kWh/1000ft{sup 2}) in the San Jose store. In each building, a kiosk was installed to display information from the project in order to educate and inform the general public about the environmental and energy-saving benefits of cool roofs. They were designed to explain cool-roof coating theory and to display real-time measurements of weather conditions, roof surface temperature, and air-conditioning electricity use. 55 figs., 15 tabs.

Konopacki, S.; Gartland, L.; Akbari, H. [Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technologies Div.; Rainer, L. [Davis Energy Group, Davis, CA (United States)

1998-06-01

207

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

SciTech Connect

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

Clark, E.A.

1992-11-21

208

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

SciTech Connect

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

Clark, E.A.

1992-11-21

209

Thermal and infrared performance of a free-standing microthermocouple  

NASA Astrophysics Data System (ADS)

This paper discusses the thermal and optical characteristics of a free-standing microthermocouple with a view to its application as an infrared detector. This device is a radiation thermocouple in which the hot junction is thermally isolated from the substrate by making it free-standing. When radiation is absorbed by the device, the free-standing structure heats while the much larger cold junction, which is in physical and thermal contact with the substrate, remains at ambient temperature. Copper and constantan have been used as the thermocouple materials. Electrical and optical measurements have been performed for free-standing wire lengths of 20, 40, and 60 ?m and have been theoretically modeled. Thermal analysis shows that convective heat loss is significant and from the measurements a convection coefficient of 20 000 W m-2 K-1, for the free-standing wires, has been deduced. The time constants of these devices were of the order of a few microseconds. The device output has been shown to depend on the polarization of the input infrared radiation. The output was largest when the free-standing wires were parallel to the polarization of the incident radiation.

Srinivas, T. A. S.; Timans, P. J.; Butcher, R. J.; Ahmed, H.

1993-12-01

210

Thermal and other tests of photovoltaic modules performed in natural sunlight  

NASA Technical Reports Server (NTRS)

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

Stultz, J. W.

1978-01-01

211

Dermal exposure and urinary 1-hydroxypyrene among asphalt roofing workers  

SciTech Connect

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

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

2007-07-01

212

Thermal Performance Testing of Order Dependancy of Aerogels Multilayered Insulation  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

213

Indoor thermal performance evaluation of Daystar solar collector  

NASA Technical Reports Server (NTRS)

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

Shih, K., Sr.

1977-01-01

214

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

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

215

Seismic qualification of building roof structure  

Microsoft Academic Search

This paper presents a method for qualifying the existing roof structure of the Fuels and Materials Examination Facility (FMEF) at the US Department of Energy`s Hanford Site in Richland, Washington. The roof is a safety class 1 structure and subject to the design-basis earthquake (DBE). The roof consists of 26 prestressed concrete T-beams 82 feet long spaced 6 feet on

M. A. Islam; R. B. Pan

1991-01-01

216

Assessment of internal condition of waste in a roofed landfill.  

PubMed

Recently, roofed landfills have been gaining popularity in Japan. Roofed landfills have several advantages over non-roofed landfills such as eliminating the visibility of waste and reducing the spread of offensive odours. This study examined the moisture balance and aeration conditions, which promote waste stabilisation, in a roofed landfill that included organic waste such as food waste. Moisture balance was estimated using waste characterization and the total amount of landfilled waste. Internal conditions were estimated based on the composition, flux, and temperature of the landfill gas. Finally, in situ aeration was performed to determine the integrity of the semi-aerobic structure of the landfill. With the effects of rainfall excluded, only 15% of the moisture held by the waste was discharged as leachate. The majority of the moisture remained in the waste layer, but was less than the optimal moisture level for biodegradation, indicating that an appropriate water spray should be administered. To assess waste degradation in this semi-aerobic landfill, the concentration and flow rate of landfill gas were measured and an in situ aeration test was performed. The results revealed that aerobic biodegradation had not occurred because of the unsatisfactory design and operation of the landfill. PMID:22989405

Zhang, Xin; Matsuto, Toshihiko

2013-01-01

217

Thermal Performance Study of a Prototype Multiport Heat Exchanger  

NASA Astrophysics Data System (ADS)

Great efforts have been made to investigate the thermal performance and fluid flow behaviour in Minichannel Heat Exchangers (MICHX), however, the examination of air side in a multiport serpentine slab heat exchanger is rare. In the current investigation, experiments were conducted on air heating via a prototype multiport MICHX. Hot DI-water at different mass flow rates and a constant inlet temperature of 70°C was passed through the channels. The water side Reynolds numbers were varied from 255 to 411. The airside Reynolds numbers were calculated based on the free mean stream velocity and varied from 1750 to 5250, while, the air inlet temperatures were in the range of 22.5°C to 34.5°C. The effects of dimensional parameters, such as Reynolds number, Nusselt number, Prandtl number, Brinkman number, and Dean number on the heat transfer performance were investigated. The effect of the serpentine on the enhancement of DI water thermal performance behaviour was studied. Heat transfer correlations were established and compared to the results in the open literature.

Fotowat, Shahram

218

Thermal expansion pump for capillary high-performance liquid chromatography.  

PubMed

A thermal expansion pump (TEP) based on a principle of liquid thermal expansion for capillary high-performance liquid chromatography has been developed. The novel pump is capable of generating a continuous flow at high pressure for constant and stable delivery of binary solvents from nanoliters to microliters per minute without splitting. Theoretical equations for controlling fluidic output of this pump have been established and validated by a series of experiments. Factors affecting flow rate, such as density discrepancy, liquid compressibility, and mass loss in output, were taken into account. An assembly of the pump system employing two groups of thermal expansion pumps (TEPs) working in turns were fabricated, and a controlling strategy for the pump system to maintain a continuous delivery without pressure fluctuation even at switching points was also developed. Both isocratic and gradients of binary solvent delivery by the TEPs were performed. Reproducibility and standard deviation at different flow rates were determined. A capillary high-performance liquid chromatography (micro-HPLC) system consisting of the TEPs, an injection valve, a homemade packed capillary column (20 cm x 100 microm i.d. with 5 microm C18), and a laser-induced fluorescence detector was set up, and sample separations were carried out. Results of RSD = 4% for flow and RSD = 2% for retention times at 500 nL/min were achieved. Such a pump system has almost no moving parts except for the solvent switches. Its overall costs of manufacture and running are very low. It is proven that the TEPs system has great potential and competitive capabilities in capillary liquid chromatography. PMID:20050677

Tao, Qian; Wu, Qian; Zhang, Xiangmin

2010-02-01

219

Thermal performance evaluation of the Semco (liquid) solar collector  

NASA Technical Reports Server (NTRS)

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.

1979-01-01

220

Thermal performance of honeywell double covered liquid solar collector  

NASA Technical Reports Server (NTRS)

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

Losey, R.

1977-01-01

221

Optical and thermal performance of a remote phosphor plate  

NASA Astrophysics Data System (ADS)

The objective of this study was to understand how optical and thermal performances are impacted in a remote phosphor LED (light-emitting diode) system when the phosphor plate thickness and phosphor concentration change with a fixed amount of a commonly used YAG:Ce phosphor. In the first part of this two-part study, an optical raytracing analysis was carried out to quantify the optical power and the color properties as a function of remote phosphor plate thickness, and a laboratory experiment was conducted to verify the results obtained from the raytracing analysis and also to examine the phosphor temperature variation due to thickness change.

Mou, Xi; Narendran, Nadarajah; Zhu, Yiting; Perera, Indika U.

2014-09-01

222

Mobile mine roof support system  

SciTech Connect

A description is given of a mobile self-propelled mine roof support system employing pairs of individually self-propelled roof support units movable along opposite ribs of a mine room to follow an advancing mine face. Each support unit comprises an elongated, wheel-mounted frame positioned along the adjacent rib. Pairs of vertical jacks are connected to opposite sides of the frame, being positioned loosely, and vertically movable, within oversize openings in brackets attached to the frame. A foot plate is universally pivotally attached to the lower ends of each pair of jacks and extends across the underside of the frame. A top-supporting canopy is universally pivotally attached across the upper ends of each pair of jacks and has an overhanging portion extending cantileverly into the room toward the opposite support unit. The jacks have external flanges engagable with the brackets. When the jacks fully retract the foot plate from the mine bottom upwardly against the underside of the frame, the entire assembly including the canopies is clamped rigidly between the brackets and the underside of the frame to lock the canopies to the frame for tramming. After the pairs of jacks press the foot plates downwardly against the bottom, the jacks shift upwardly to disengage their external flanges from the brackets and to press the canopies against the mine top. In an alternate embodiment, the ends of the canopies of the opposite roof support units are interconnected by wire ropes or chains and tensioned by hydraulic cylinders to support the top at the center of the room. A horizontally swingable inbye section of the frame has at least one canopy to continuously support the top when the mining operation changes direction, as when it makes a breakthrough from one room to another.

Nelson, R.C.

1981-12-29

223

Integrated heat pipe-thermal storage system performance evaluation  

SciTech Connect

Performance verification tests of an integrated heat pipe-thermal energy storage system have been conducted. This system is being developed as a part of an Organic Rankine Cycle-Solar Dynamic Power System (ORC-SDPS) receiver for future space stations. The integrated system consists of potassium heat pipe elements that incorporate thermal energy storage (TES) canisters within the vapor space along with an organic fluid (toluene) heater tube used as the condenser region of the heat pipe. During the insolation period of the earth orbit, solar energy is delivered to the surface of the heat pipe elements of the ORC-SDPS receiver and is internally transferred by the potassium vapor for use and storage. Part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the stored energy in the TES units is transferred by the potassium vapor to the toluene heater tube. A developmental heat pipe element was fabricated that employs axial arteries and a distribution wick connecting the wicked TES units and the heater to the solar insolation surface of the heat pipe. Tests were conducted to verify the heat pipe operation and to evaluate the heat pipe/TES units/heater tube operation by interfacing the heater unit to a heat exchanger.

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

1987-01-01

224

Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

225

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

SciTech Connect

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

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

2013-01-01

226

Miniaturized high-performance starring thermal imaging system  

NASA Astrophysics Data System (ADS)

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

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

2000-07-01

227

Improving the performance of lysimeters with thermal imaging  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

228

29 CFR Appendix A to Subpart M of... - Determining Roof Widths  

Code of Federal Regulations, 2010 CFR

...CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Fall Protection Pt. 1926, Subpt. M, App. A Appendix A to Subpart...use of a safety monitoring system alone as a means of providing fall protection during the performance of roofing...

2010-07-01

229

29 CFR Appendix A to Subpart M of... - Determining Roof Widths  

Code of Federal Regulations, 2011 CFR

...CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Fall Protection Pt. 1926, Subpt. M, App. A Appendix A to Subpart...use of a safety monitoring system alone as a means of providing fall protection during the performance of roofing...

2011-07-01

230

40 CFR 1037.140 - Curb weight and roof height.  

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

231

40 CFR 1037.140 - Curb weight and roof height.  

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

232

40 CFR 1037.140 - Curb weight and roof height.  

Code of Federal Regulations, 2014 CFR

...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...

2014-07-01

233

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

234

High Performance Thermal Imaging Using Quantum Well Infrared Photodetector Arrays  

NASA Astrophysics Data System (ADS)

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.

Schneider, Harald

2007-03-01

235

Thermal Performance of Cryogenic Multilayer Insulation at Various Layer Spacings  

NASA Technical Reports Server (NTRS)

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

Johnson, Wesley Louis

2010-01-01

236

SOUND TRANSMISSION LOSS OF GREEN ROOFS  

Microsoft Academic Search

Green roofs have the potential to provide excellent external\\/internal sound isolation due to their high mass, low stiffness and damping effect, and through surface absorption, reduce noise pollution in the community from aircraft, elevated transit systems, industrial sites and noise build-up in urban areas. This paper reviews the acoustical characteristics and the potential contributions of green roofs to the acoustical

Maureen Connelly; Murray Hodgson

237

OPTIMIZING GREEN ROOF TECHNOLOGIES IN THE MIDWEST  

EPA Science Inventory

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

238

Lightweight, self-ballasting photovoltaic roofing assembly  

DOEpatents

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

Dinwoodie, T.L.

1998-05-05

239

CONCRETE, MASONRY, ROOFING, AND RESIDENTIAL CONSTRUCTION  

E-print Network

EM 385-1-1 XX Sep 13 i Section 27 CONCRETE, MASONRY, ROOFING, AND RESIDENTIAL CONSTRUCTION Table.....................................27-9 27.E Lift-Slab Operations..................................................27-9 27.F Masonry-1-1 XX Sep 13 27-1 SECTION 27 CONCRETE, MASONRY, ROOFING, AND RESIDENTIAL CONSTRUCTION 27.A GENERAL

US Army Corps of Engineers

240

Roofs--Their Problems and Solutions.  

ERIC Educational Resources Information Center

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…

Swentkofske, Carl J.

241

Lightweight, self-ballasting photovoltaic roofing assembly  

DOEpatents

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

Dinwoodie, Thomas L. (Berkeley, CA)

1998-01-01

242

Roofing as a source of nonpoint water pollution  

Microsoft Academic Search

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

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

2004-01-01

243

29 CFR 570.67 - Occupations in roofing operations and on or about a roof (Order 16).  

Code of Federal Regulations, 2010 CFR

...of existing roofs; the construction of the sheathing or base of roofs (wood or metal), including roof trusses or joists; gutter and downspout work; the installation and servicing of television and communication equipment such as cable and...

2010-07-01

244

SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature  

SciTech Connect

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

Robert Rimmer; Jay Benesch; Joseph Preble; Charles Reece

2005-05-01

245

Thermal performance evaluation of the Calmac (liquid) solar collector  

NASA Technical Reports Server (NTRS)

The procedures used and the results obtained during the evaluation test program on the S. N. 1, (liquid) solar collector are presented. The flat plate collector uses water as the working fluid. The absorber plate is aluminum with plastic tubes coated with urethane black. The glazing consists of .040 in fiberglass reinforced polyester. The collector weight is 78.5 pounds with overall external dimensions of approximately 50.3in. x 98.3in. x 3.8in. The following information is given: thermal performance data under simulated conditions, structural behavior under static loading, and the effects of long term exposure to natural weathering. These tests were conducted using the MSFC Solar Simulator.

Usher, H.

1978-01-01

246

Performance of beryllium, carbon, and tungsten under intense thermal fluxes  

NASA Astrophysics Data System (ADS)

Transient heat loads on a millisecond timescale with deposited energy densities beyond 1 MJ m -2 have been simulated in a plasma accelerator facility (VIKA) and in two high power electron beam teststands (JUDITH, JEBIS). Main objective of these experiments was to study and to compare the behaviour of different plasma facing materials (Be, CFC, W) under heat loads which occur during disruptions in future thermonuclear fusion reactors such as ITER. In these tests special attention was paid to the thermal shock resistance, the processes during melt layer formation, and the resulting material erosion. To perform these tests specific loading techniques and diagnostics have been developed and applied. Among these are high heat flux loading experiments at elevated temperatures ( T > DBTT) of the test coupons, fast surface pyrometry, and reliable techniques for the quantification of the absorbed energy.

Linke, J.; Akiba, M.; Bolt, H.; Breitbach, G.; Duwe, R.; Makhankov, A.; Ovchinnikov, I.; Rödig, M.; Wallura, E.

1997-02-01

247

Thermal Performance of Capillary Pumped Loops Onboard Terra Spacecraft  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

248

Parametric study of solar thermal rocket nozzle performance  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

249

A comprehensive numerical model examining the thermal performance of airships  

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

250

Measuring mine roof bolt strains  

SciTech Connect

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.

Steblay, B.J.

1986-07-22

251

Software Optimization for Performance, Energy, and Thermal Distribution: Initial Case Studies  

E-print Network

Software Optimization for Performance, Energy, and Thermal Distribution: Initial Case Studies Md can help achieve higher energy efficiency and better thermal behavior. We use both direct measurements- sired level of performance while reducing energy consumption. A closely related issue is thermal

Herbordt, Martin

252

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

SciTech Connect

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

Not Available

1994-02-01

253

The Effect of Thermal Load Configurations on Passive Chilled Beam Performance  

E-print Network

for the beam cooling capacity to predict the beam performance based on the room thermal conditions. The experimental data revealed an average reduction of 15% in the passive beam cooling capacity for the asymmetrically configured thermal manikins compared...

Nelson, Ian 1982-

2012-11-15

254

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

E-print Network

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

Park, Chan Hyun

2012-07-16

255

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

E-print Network

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

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

2003-01-01

256

HIGH-PERFORMANCE PHASECHANGE THERMAL ENERGY STORAGE USING SPHERICAL CAPSULES  

Microsoft Academic Search

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

T. SAITOH; K. HIROSE

1986-01-01

257

Role of Random Roughness On Thermal Performance of Microfins  

E-print Network

in a variety of appli- cations in micro-electro-mechanical systems (MEMS) such as thermal actuators in RF devices [1], thermal flexture actuators [2], and thermal-compliant microactuators [3]. Micropin fin heat, and molding. The polycrystalline silicon substrates used in micro- mechanical devices are often rough

Bahrami, Majid

258

Assessment of Relevant Physical Phenomena Controlling Thermal Performance of Nanofluids  

E-print Network

of obtaining large enhancements (up to 40%) in thermal conductivity compared with the base liquid [5], strong thermal conductivity of nanofluids. Through an investigation, a large degree of randomness and scatter has conductivity, W=mK n = 3= a parameter in Eq. (2) Q = heat flow rate, W rp = particle radius, m R = thermal

Bahrami, Majid

259

Numerical analysis of heat transfer by conduction and natural convection in loose-fill fiberglass insulation--effects of convection on thermal performance  

SciTech Connect

A two-dimensional code for solving equations of convective heat transfer in porous media is used to analyze heat transfer by conduction and convection in the attic insulation configuration. The particular cases treated correspond to loose-fill fiberglass insulation, which is characterized by high porosity and air permeability. The effects of natural convection on the thermal performance of the insulation are analyzed for various densities, permeabilities, and thicknesses of insulation. With convection increasing the total heat transfer through the insulation, the thermal resistance was found to decrease as the temperature difference across the insulating material increases. The predicted results for the thermal resistance are compared with data obtained in the large-scale climate simulator at the Roof Research Center using the attic test module, where the same phenomenon has already been observed. The way the wood joists within the insulation influence the start of convection is studied for differing thermophysical and dynamic properties of the insulating material. The presence of wood joists induces convection at a lower temperature difference.

Delmas, A.A.; Wilkes, K.E.

1992-04-01

260

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

Microsoft Academic Search

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

Hassan E. S. Fath

1995-01-01

261

Thermal Performance Evaluation of Attic Radiant Barrier Systems Using the Large Scale Climate Simulator (LSCS)  

SciTech Connect

Application of radiant barriers and low-emittance surface coatings in residential building attics can significantly reduce conditioning loads from heat flow through attic floors. The roofing industry has been developing and using various radiant barrier systems and low-emittance surface coatings to increase energy efficiency in buildings; however, minimal data are available that quantifies the effectiveness of these technologies. This study evaluates performance of various attic radiant barrier systems under simulated summer daytime conditions and nighttime or low solar gain daytime winter conditions using the large scale climate simulator (LSCS). The four attic configurations that were evaluated are 1) no radiant barrier (control), 2) perforated low-e foil laminated oriented strand board (OSB) deck, 3) low-e foil stapled on rafters, and 4) liquid applied low-emittance coating on roof deck and rafters. All test attics used nominal RUS 13 h-ft2- F/Btu (RSI 2.29 m2-K/W) fiberglass batt insulation on attic floor. Results indicate that the three systems with radiant barriers had heat flows through the attic floor during summer daytime condition that were 33%, 50%, and 19% lower than the control, respectively.

Shrestha, Som S [ORNL] [ORNL; Miller, William A [ORNL] [ORNL; Desjarlais, Andre Omer [ORNL] [ORNL

2013-01-01

262

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

SciTech Connect

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.

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

1994-05-01

263

Roof Coating Procedures and Their Productivity Gains  

E-print Network

Roof Coating Procedures and their Productivity Gains John Bonaby and Dr. Diane Schaub, University of Florida As building envelope improvements are realized in organizations as ways to insulate businesses from high energy costs, the relative...

Bonaby, J.; Schaub, D.

2006-01-01

264

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

Microsoft Academic Search

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

Atipoang Nuntaphan; Choosak Chansena; Tanongkiat Kiatsiriroat

2009-01-01

265

Rectilinear building roof contour extraction based on snakes and dynamic programming  

NASA Astrophysics Data System (ADS)

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

Fazan, Antonio Juliano; Dal Poz, Aluir Porfírio

2013-12-01

266

Thermal performance of residential duct systems in basements  

SciTech Connect

There are many unanswered questions about the typical effects of duct system operation on the infiltration rates and energy usage of single- family residences with HVAC systems in their basements. In this paper, results from preliminary field studies and computer simulations are used to examine the potential for improvements in efficiency of air distribution systems in such houses. The field studies comprise thermal and flow measurements on four houses in Maryland. The houses were found to have significant envelope leakage, duct leakage, and duct conduction losses. Simulations of a basement house, the characteristics of which were chosen from the measured houses, were performed to assess the energy savings potential for basement house. The simulations estimate that a nine percent reduction in space conditioning energy use is obtained by sealing eighty percent of the duct leaks and insulating ducts to an R-value of 0.88 {degree}C{center_dot}m{sup 2}/W (5{degree}F{center_dot}ft{sup 2}{center_dot}h/BTU) where they are exposed in the basement. To determine the maximum possible reduction m energy use, simulations were run with all ducts insulated to 17.6 {degree}C{center_dot}m{sup 2}/W (100 {degree}F{center_dot}ft{sup 2}{center_dot}h/BTU) and with no duct leakage. A reduction of energy use by 14% is obtained by using perfect ducts instead of nominal ducts.

Treidler, B.; Modera, M.

1994-02-01

267

Performance assessment of low pressure nuclear thermal propulsion  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

268

Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions  

PubMed Central

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

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

2010-01-01

269

Experimental investigations of fluid dynamic and thermal performance of nanofluids  

NASA Astrophysics Data System (ADS)

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.

Kulkarni, Devdatta Prakash

270

Thyristor Valve Gapless Arrester Element Lifetime Performance and Thermal Stability  

Microsoft Academic Search

For the purpose of developing thyristor valve gapless arrester, a ZnO element was developed and examination was conducted on such characteristics of gapless arrester as life characteristic, thermal runaway characteristic and surge withstand capability, these being essential to rational design of thyristor valve gapless arrester. Especially for evaluating the life characteristic and thermal runaway, a small-scale 3- phase bridge thyristor

H. Nishikawa; M. Sukehara; T. Yoshida; S. Kobayashi; T. Takahashi; N. Amiji; T. Sasaki; S. Tanabe

1985-01-01

271

Thermal performance evaluation of an insulation system for cast resin power transformers  

Microsoft Academic Search

The thermal performance evaluation study is based on a proper thermal characterization of the PET (polyethylene terephthalate) film to be used as part of the insulation system. The film is tested in conditions similar to the ones present in the intended application and a meaningful set of data is obtained, which makes it possible to draw the relevant thermal life

L. Centurioni; G. Coletti; D. Tommasini

1988-01-01

272

Design and calibration of a test facility for MLI thermal performance measurements below 80K  

Microsoft Academic Search

The design geometry of the SSC dipole cryostat includes active thermal radiation shields operating at 80K and 20K respectively. Extensive measurements conducted in a Heat Leak Test Facility (HLTF) have been used to evaluate the thermal performance of candidate multilayer insulation (MLI) systems for the 80K thermal shield, with the present system design based upon those measurement results. With the

W. Boroski; R. Kunzelman; M. Ruschman; C. Schoo

1992-01-01

273

A simple dynamic measurement technique for comparing thermal insulation performances of anisotropic building materials  

Microsoft Academic Search

Measuring or estimating thermal properties of anisotropic building materials can be key obtaining the optimum performance for a particular application. The intensive researches on development of new building materials have necessitated in situ thermal testing apparatuses in most research laboratories. Only few standardized techniques are available for accurate thermal testing of anisotropic materials, and they are generally expensive. In the

Bulent Yesilata; Paki Turgut

2007-01-01

274

Influence of concrete fracture on the rain infiltration and thermal performance of building facades  

E-print Network

and thermal issues. Specific simulation cases of insulated and non-insulated building facades were definedInfluence of concrete fracture on the rain infiltration and thermal performance of building facades., Foray G., Roux J.-J., 2013. Influence of concrete fracture on the rain infiltration and thermal

275

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

NASA Astrophysics Data System (ADS)

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

Prakash, D.; Ravikumar, P.

2014-01-01

276

Performance of Thermal Insulation Containing Microencapsulated Phase Change Material  

SciTech Connect

The objective of this study is dynamic thermal performance microencapsulated phase change material (PCM) blended with loose-fill cellulose insulation. Dynamic hot-box testing and heat-flux measurements have been made for loose-fill cellulose insulation with and without uniformly distributed microencapsulated PCM. The heat flux measurements were made with a heat-flow-meter (HFM) apparatus built in accordance with ASTM C 518. Data were obtained for 1.6 lb{sub m}/ft{sup 3} cellulose insulation containing 0 to 40 wt% PCM. Heat-flux data resulting from a rapid increase in the temperature on one side of a test specimen initially at uniform temperature were analyzed to access the effect of PCM on total heat flow. The heat flux was affected by the PCM for about 100 minutes after the temperature increase. The total heat flow during this initial period decreased linearly with PCM content from 6.5 Btu/ft{sup 2} at 0% PCM to 0.89 Btu/ft{sup 2} for 40 wt% PCM. The cellulose insulation with PCM discharged heat faster than the untreated cellulose when the hot-side temperature of the test specimen was reduced. In addition, hot-box apparatus built in accordance with ASTM C 1363 was utilized for dynamic hot-box testing of a wood stud wall assembly containing PCM-enhanced cellulose insulation. Experimental data obtained for wood-frame wall cavities containing cellulose insulation with PCM was compared with results obtained from cavities containing only cellulose insulation.

Kosny, Jan [ORNL] [ORNL; Yarbrough, David [R & D Services] [R & D Services; Syed, Azam M [ORNL] [ORNL

2007-01-01

277

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

278

Automatic roof outlines reconstruction from photogrammetric DSM  

E-print Network

The extraction of geometric and semantic information from image and range data is one of the main research topics. Between the different geomatics products, 3D city models have shown to be a valid instrument for several applications. As a consequence, the interest for automated solutions able to speed up and reduce the costs for 3D model generation is greatly increased. Image matching techniques can nowadays provide for dense and reliable point clouds, practically comparable to LiDAR ones in terms of accuracy and completeness. In this paper a methodology for the geometric reconstruction of roof outlines (eaves, ridges and pitches) from aerial images is presented. The approach keeps in count the fact the usually photogrammetrically derived point clouds and DSMs are more noisy with respect to LiDAR data. A data driven approach is used in order to keep the maximum flexibility and to achieve satisfying reconstructions with different typologies of buildings. Some tests and examples are reported showing the suitability of photogrammetric DSM for this topic and the performances of the developed algorithm in different operative conditions. 1.

F. Nex; F. Remondino

2012-01-01

279

NISTIR 7401 Thermal Performance of Fire Resistive Materials  

E-print Network

and certified based on lab-scale fire tests such as those described in the ASTM E119 Standard Test Methods capacity, thermal conductivity, and enthalpies of reactions and phase changes. In this report, procedures

Bentz, Dale P.

280

Thermal fatigue performance of integrally cast automotive turbine wheels  

NASA Technical Reports Server (NTRS)

Fluidized bed thermal fatigue testing was conducted on 16 integrally cast automotive turbine wheels for 1000-10,000 (600 sec total) thermal cycles at 935/50 C. The 16 wheels consisted of 14 IN-792 + 1% Hf and 2 gatorized AF2-1DA wheels; 6 of the IN-792 + Hf wheels contained crack arrest pockets inside the blade root flange. Temperature transients during the thermal cycling were measured in three calibration tests using either 18 or 30 thermocouples per wheel. Thermal cracking based on crack length versus accumulated cycles was greatest for unpocketed wheels developing cracks in 8-13 cycles compared to 75-250 cycles for unpocketed wheels. However, pocketed wheels survived up to 10,000 cycles with crack lengths less than 20 mm, whereas two unpocketed wheels developed 45 mm long cracks in 1000-2000 cycles.

Humphreys, V. E.; Hofer, K. E.

1980-01-01

281

Radiative transfer and thermal performance levels in foam insulation boardstocks  

E-print Network

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

Moreno, John David

1991-01-01

282

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

PubMed

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

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

2014-08-15

283

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

284

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

PubMed

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

Razzaghmanesh, M; Beecham, S

2014-11-15

285

Thermal performance of phase change wallboard for residential cooling application  

Microsoft Academic Search

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

Helmut E. Feustel; Corina Stetiu

1997-01-01

286

Performance Comparison of Modular Photovoltaic-Thermal Solar Panels  

Microsoft Academic Search

The purpose of this experiment was to create a modular photovoltaic-thermal panel, which would be easily implemented and maintained. Three different prototype panels were tested simultaneously. The system was fixed at the optimal angle of 37.95° for the local area (Rolla, Missouri).The first two panels (Panel A & B) consisted of a highly conductive thermal sheeting and different sized copper

Nicole C. Annis; Stuart W. Baur

2011-01-01

287

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

NASA Technical Reports Server (NTRS)

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

Wales, R. O. (editor)

1981-01-01

288

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

Microsoft Academic Search

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,

Ahmet Sar?; Kamil Kaygusuz

2001-01-01

289

Thermal performance analysis for heat exchangers having a variable overall heat transfer coefficient  

Microsoft Academic Search

The classic, conventional analysis for the thermal performance of heat exchangers is based on three assumptions: constant fluid flow rate, constant specific heat fluids, and constant overall heat transfer coefficient. Our analysis describes a general approach for analyzing the thermal performance of heat exchangers in which the overall heat transfer coefficient varies as a function of enthalpy, with the other

J. C. Conklin; E. Granryd

1991-01-01

290

Dynamic test method for determining the thermal performances of heat pipes  

Microsoft Academic Search

With a view toward shortening the necessary time to examine the thermal performances of heat pipes, a novel dynamic test method is originated and compared to the conventional steady-states test. A set of dynamic parameters of thermal performances of heat pipes is ideated from the observed transient phenomenon. Bending angles, fill ratios, and shapes of heat pipes are investigated in

Te-En Tsai; Guan-Wei Wu; Chih-Chung Chang; Wen-Pin Shih; Sih-Li Chen

2010-01-01

291

Determination of thermal performance characteristics of modular passive solar storage walls  

SciTech Connect

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

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

1980-01-01

292

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

293

a Line-Based 3d Roof Model Reconstruction Algorithm: Tin-Merging and Reshaping (tmr)  

NASA Astrophysics Data System (ADS)

Three-dimensional building model is one of the major components of a cyber-city and is vital for the realization of 3D GIS applications. In the last decade, the airborne laser scanning (ALS) data is widely used for 3D building model reconstruction and object extraction. Instead, based on 3D roof structural lines, this paper presents a novel algorithm for automatic roof models reconstruction. A line-based roof model reconstruction algorithm, called TIN-Merging and Reshaping (TMR), is proposed. The roof structural line, such as edges, eaves and ridges, can be measured manually from aerial stereo-pair, derived by feature line matching or inferred from ALS data. The originality of the TMR algorithm for 3D roof modelling is to perform geometric analysis and topology reconstruction among those unstructured lines and then reshapes the roof-type using elevation information from the 3D structural lines. For topology reconstruction, a line constrained Delaunay Triangulation algorithm is adopted where the input structural lines act as constraint and their vertex act as input points. Thus, the constructed TINs will not across the structural lines. Later at the stage of Merging, the shared edge between two TINs will be check if the original structural line exists. If not, those two TINs will be merged into a polygon. Iterative checking and merging of any two neighboured TINs/Polygons will result in roof polygons on the horizontal plane. Finally, at the Reshaping stage any two structural lines with fixed height will be used to adjust a planar function for the whole roof polygon. In case ALS data exist, the Reshaping stage can be simplified by adjusting the point cloud within the roof polygon. The proposed scheme reduces the complexity of 3D roof modelling and makes the modelling process easier. Five test datasets provided by ISPRS WG III/4 located at downtown Toronto, Canada and Vaihingen, Germany are used for experiment. The test sites cover high rise buildings and residential area with diverse roof type. For performance evaluation, the adopted roof structural lines are manually measured from the provided stereo-pair. Experimental results indicate a nearly 100% success rate for topology reconstruction was achieved provided that the 3D structural lines can be enclosed as polygons. On the other hand, the success rate at the Reshaping stage is dependent on the complexity of the rooftop structure. Thus, a visual inspection and semi-automatic adjustment of roof-type is suggested and implemented to complete the roof modelling. The results demonstrate that the proposed scheme is robust and reliable with a high degree of completeness, correctness, and quality, even when a group of connected buildings with multiple layers and mixed roof types is processed.

Rau, J.-Y.

2012-07-01

294

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

295

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

NASA Technical Reports Server (NTRS)

A large telescope aperture, stringent thermal stability and temperature range requirements, and a passively-cooled 1500K module presented major challenges in thermal design and hardware fabrication of this Small Explorer satellite. This paper reviews briefly the thermal design of the SWAS science instrument, and examines the first three months of on-orbit thermal history. Measured temperatures for both the science payload and the spacecraft module and solar arrays are compared with those predicted by the correlated analytical model. Similarities and differences are interpreted in terms of the major uncertainties remaining after thermal-balance testing, especially those of MLI performance and telescope aperture properties. Review of the thermal model adequacy and thermal design verification are included to suggest improvements in the thermal design process for future missions.

Boyd, David A.; Ousley, Wes; Fantano, Louis

1999-01-01

296

Thermal performance of windows having high solar transmittance  

SciTech Connect

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

Rubin, M.; Selkowitz, S.

1981-07-01

297

Weathering of Roofing Materials-An Overview  

SciTech Connect

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

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

2006-03-30

298

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

SciTech Connect

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.

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

2009-08-28

299

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

SciTech Connect

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.

Raghuraman, P.

1980-04-30

300

The wind resistance of asphalt roofing shingles  

NASA Astrophysics Data System (ADS)

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

Dixon, Craig Robert

301

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

PubMed

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

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

2012-05-01

302

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

NASA Technical Reports Server (NTRS)

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.

Zhu, Dongming; Miller, Robert A.

2008-01-01

303

Performance Simulation and Thermal Stress Analysis of Ceramic Recuperators formed by SiC and MAS  

Microsoft Academic Search

This study conducted performance simulations for ceramic recuperators and performed thermal stress analysis to provide reliable guidance for heat recuperator designers. A numerical simulation was conducted utilizing STAR-CD to predict thermal and pressure flow fields inside two 50 W ceramic compact heat exchangers, one made of SiC and the other made of MAS. The predicted temperature and pressure profiles from performance

Chun-Hsiang Yang; Ming-Ta Yu; Chiun-Heng Chen; Chiun-Hsun Chen

2008-01-01

304

Interior view of the Sheet Metal Shop showing the roof ...  

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

Interior view of the Sheet Metal Shop showing the roof trusses and corrugated metal roof covering, view facing northwest - Kahului Cannery, Plant No. 28, Boiler House, Sheet Metal and Electrical Shops, 120 Kane Street, Kahului, Maui County, HI

305

Evaluation of a Direct Evaporative Roof-Spray Cooling System  

E-print Network

Roof-Spray cooling systems are being extensively used to reduce the air-conditioning usage in industrial and commercial buildings. In buildings without air-conditioning, evaporative roof spray cooling systems help to reduce the interior temperatures...

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

1987-01-01

306

Theory vs. Practice in Direct Evaporative Roof Spray Cooling  

E-print Network

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...

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

1985-01-01

307

Thermal Performance of a Capillary Pumped Loop for Automotive Cooling  

Microsoft Academic Search

The design and test results for a capillary pumped loop (CPL) for thermal management of up to 210 W at the source and heat transfer over a distance of 1 m are discussed. The design configuration of the CPL evaporator consists of an internally grooved aluminum evaporator, 31.70-mm outer diameter and 500-mm long, fitted with a porous ultra-high molecular weight

R. Singh; A. Akbarzadeh; M. Mochizuki

2008-01-01

308

Flightweight radiantly and actively cooled panel: Thermal and structural performance  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

309

Ballistic Performance of Porous-Ceramic, Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

310

Ballistic Performance of Porous-Ceramic, Thermal Protection Systems  

NASA Astrophysics Data System (ADS)

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 also highly exposed to space environment hazards like solid particle impacts. This paper discusses impact testing up to 9.65 km/s on one of these systems. The materials considered are 8 lb/ft^3 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. A model extension to look at the implications of greater than 10 GPa equation of state measurements is also discussed. Predicted penetration probabilities for a vehicle visiting the International Space Station is 60% lower for orbital debris and 95% lower for meteoroids with this model compared to an energy scaled approach.

Miller, Joshua; Bohl, William; Christiansen, Eric; Davis, B. Alan; Foreman, Cory

2011-06-01

311

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

SciTech Connect

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

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

2014-08-01

312

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

313

Attic or Roof? An Evaluation of Two Advanced Weatherization Packages  

SciTech Connect

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

Neuhauser, K.

2012-06-01

314

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

NASA Technical Reports Server (NTRS)

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

Humphries, W. R.

1974-01-01

315

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

SciTech Connect

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.

Raghuraman, P.; Hendrie, S.D.

1980-01-01

316

Apparatus for accurate measurement of interface resistance of high performance thermal interface materials  

Microsoft Academic Search

This manuscript describes a systematic and rational design of an experimental apparatus based on ASTM D-5470 standard for thermal interface resistance measurement of high performance thermal interface materials (TIM). The apparatus is intended to provide measurement of TIM thermal resistance as low as 0.065 K-cm2\\/W within 10% experimental uncertainty. The key points addressed are: 1) Apparatus design to obtain accurate

J. P. Gwinn; M. Saini; R. L. Webb

2002-01-01

317

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

NASA Technical Reports Server (NTRS)

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

Ko, William L.

2004-01-01

318

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

319

ROOFING PROJECT ODORS How Can EHS Help?  

E-print Network

ROOFING PROJECT ODORS How Can EHS Help? We can work with occupants to act as a liaison with Facili very low odor thresholds (lowest concentration that can be detected by the hu- man olfactory system. Is This Short-Term or Long-Term? Short-term. These are unpleasant, transient and can be relieved by ceasing

Stephens, Graeme L.

320

Thrust bolting: roof bolt support apparatus  

DOEpatents

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.

Tadolini, Stephen C. (Lakewood, CO); Dolinar, Dennis R. (Golden, CO)

1992-01-01

321

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...

322

Operation behaviour of roof installed photovoltaic modules  

Microsoft Academic Search

Photovoltaic energy in the building environment is a very interesting application. On existing building roofs, the installation of photovoltaic generators is a common mounting configuration. It is important to assess and predict the operational behaviour regarding energy output, power rating and critical operation limits of such modules. This contribution summarizes some detailed experimental and theoretical examinations regarding the operational behaviour

Werner Knaupp

1996-01-01

323

Roofing with Urethane: Pro and Con.  

ERIC Educational Resources Information Center

Gerald Scott's favorable evaluation of the foamed polyurethane roofing system is based on experiences with 55 buildings at Texas A & M. Michael Kinzer, an architect at Colorado State University, disagrees and claims that the system is difficult to install and maintain, and the cost prohibitive. (MLF)

Kinzer, Michael; Scott, Gerald P.E.

1981-01-01

324

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2010 CFR

...mechanically anchored tensioned roof bolts shall be measured from the outby corner of the last open crosscut to the face in each advancing section. Corrective action shall be taken if the majority of the bolts measured— (i) Do not maintain at least 70...

2010-07-01

325

ROOF FALL CAVE, CANIA GORGE: SITE REPORT  

Microsoft Academic Search

This site report presents a description of archaeological investigations undertaken at Roof Fall Cave. an occupied rockshelter and an site located at Cania Gorge. eastern Central Queensland. Field and laboratory methods are outlined and preliminaly results are presented. Excavation yielded quantities of stone artefacts, hone and charcoal. along with some freshwater mussel shell and ochre with an occupational sequence spanning

TONY EALES; CATHERINE WESTCOTT; IAN LILLEY; SEAN ULM; DEBORAH BRIAN; CHRIS CLARKSON

326

Thermal cure effects on electrical performance of nanoparticle silver inks Julia R. Greer *, Robert A. Street  

E-print Network

Thermal cure effects on electrical performance of nanoparticle silver inks Julia R. Greer *, Robert September 2007 Abstract Physical, electrical, and morphological properties of thermally annealed silver; Sintering; Nano-inks 1. Introduction Metal nano-inks consist of a colloidal suspension of nanometer

Greer, Julia R.

327

Thermal performance evaluation for a microelectronics motor control system incorporating dynamic heat sources  

Microsoft Academic Search

A detailed transient thermal analysis for single-chip silicon Integrated Motor Control System with multiple dynamic heat sources with various applications in electronics packaging is performed using numerical simulations. The challenge resides in the transient thermal interaction between various dynamic heat sources, operating at high power surges for short time frames (in one case, the motor dissipates 120 W for 2.56

Victor Chiriac; Tien-Yu Tom Lee

2004-01-01

328

Modelling the thermal performance of earth-to-air heat exchangers  

Microsoft Academic Search

A new complete numerical model for the prediction of thermal performance of the earth-to-air heat exchangers is presented. The model describes the simultaneous heat and mass transfer inside the tube and into the soil accounting for the soil natural thermal stratification. The model is validated against an extensive set of experimental data and it is found accurate. The proposed algorithms

G. Mihalakakou; M. Santamouris; D. Asimakopoulos

1994-01-01

329

Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models  

E-print Network

1 Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models distilled from measure data, rather than models derived from transformer heat for measuring the acceptability of transformer thermal models. For a model to be acceptable, it must have

330

Ground heat transfer effects on the thermal performance of earth-contact structures  

Microsoft Academic Search

A review of ground heat transfer effects on the thermal performance of earth contact structures is presented. The fundamental heat transfer processes relevant to the problem are described along with methods of determining thermal properties of soils. An overview of the many analytical, semi-analytical and numerical methods available to solve the heat transfer problem is also provided, followed by a

S. W. Rees; M. H. Adjali; Z. Zhou; M. Davies; H. R. Thomas

2000-01-01

331

Visualizing the thermal performance of heat pipes with thermochromic liquid crystals  

Microsoft Academic Search

A novel technique has been developed to visualized the thermal performance characteristics of simple low temperature heat pipes and thermosyphons. Copper heat pipes with internal, annular mesh wicks and charged with Refrigerant-12 were externally coated with thermochromic liquid crystal (TLC) paints. The thermally sensitive TLC coating reversibly changes color upon heating and readily permits visual identification of transient and steady

Fred S. Gunnerson; Glen E. Thorncroft

1991-01-01

332

An experimental investigation of the thermal performance of an asymmetrical flat plate heat pipe  

Microsoft Academic Search

An experimental investigation of the thermal performance of a flat plate heat pipe is presented in this work. The results indicate that the temperature along the heat pipe wall surfaces is quite uniform. The results also indicate that the porous wick of the evaporator section creates the main thermal resistance resulting in the largest temperature drop, which consequently affects the

Y. Wang; K. Vafai

2000-01-01

333

Modeling of thermal via heat transfer performance for power electronics cooling  

Microsoft Academic Search

For power electronics and Light Emitting Diode (LED) lighting applications, thermal management represents a critical factor having important consequences on electrical performance and overall cost of the assembly. Although advanced solutions for heat removal like Isolated Metal Substrates (IMS) base materials or thermally conductive epoxies have entered the market for a few years they still have a high price tag

Catalin Negrea; Paul Svasta

2011-01-01

334

EVOLUTION OF ANTENNA PERFORMANCE FOR APPLICATIONS IN THERMAL MEDICNE  

PubMed Central

This presentation provides an overview of electromagnetic heating technology that has proven useful in clinical applications of hyperthermia therapy for cancer. Several RF and microwave antenna designs are illustrated which highlight the evolution of technology from simple waveguide antennas to spatially and temporally adjustable multiple antenna phased arrays for deep heating, conformal arrays for superficial heating, and compatible approaches for radiometric and magnetic resonance image based non-invasive thermal monitoring. Examples of heating capabilities for several recently developed applicators demonstrate highly adjustable power deposition that has not been possible in the past. PMID:23487445

Stauffer, P.R.; Maccarini, P.F.

2013-01-01

335

Millikelvin thermal and electrical performance of lossy transmission line filters  

SciTech Connect

We report on the scattering parameters and Johnson noise emission of low-pass stripline filters employing a magnetically loaded silicone dielectric down to 25 mK. The transmission characteristic of a device with f-3dB=1.3 GHz remains essentially unchanged upon cooling. Another device with f-edB=0.4 GHz, measured in its stopband, exhibits a steady state noise power emission consistent with a temperature difference of a few mK relative to a well-anchored cryogenic microwave attenuator at temperatures down to 25 mK, thus presenting a matched thermal load.

Slichter, Daniel; Naaman, Ofer; Siddiqi, Irfan

2009-03-11

336

Process of making cryogenically cooled high thermal performance crystal optics  

DOEpatents

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.

Kuzay, Tuncer M. (Naperville, IL)

1992-01-01

337

Variation in thermal performance and reaction norms among populations of Drosophila melanogaster.  

PubMed

The major goal of evolutionary thermal biology is to understand how variation in temperature shapes phenotypic evolution. Comparing thermal reaction norms among populations from different thermal environments allows us to gain insights into the evolutionary mechanisms underlying thermal adaptation. Here, we have examined thermal adaptation in six wild populations of the fruit fly (Drosophila melanogaster) from markedly different natural environments by analyzing thermal reaction norms for fecundity, thorax length, wing area, and ovariole number under ecologically realistic fluctuating temperature regimes in the laboratory. Contrary to expectation, we found only minor differences in the thermal optima for fecundity among populations. Differentiation among populations was mainly due to differences in absolute (and partly also relative) thermal fecundity performance. Despite significant variation among populations in the absolute values of morphological traits, we observed only minor differentiation in their reaction norms. Overall, the thermal reaction norms for all traits examined were remarkably similar among different populations. Our results therefore suggest that thermal adaptation in D. melanogaster predominantly involves evolutionary changes in absolute trait values rather than in aspects of thermal reaction norms. PMID:24299409

Klepsatel, Peter; Gáliková, Martina; De Maio, Nicola; Huber, Christian D; Schlötterer, Christian; Flatt, Thomas

2013-12-01

338

Thermal performance of the ARATEX Services, Inc. solar energy system  

Microsoft Academic Search

The International Business Machines Corporation is contributing to the National Solar Data Program of the Department of Energy by monitoring, evaluating, and reporting the performance of designated solar-energy systems. The ARATEX Services, Inc. solar-energy system for preheating process water in an industrial laundry in Fresno, CA, and its modes of operation are briefly described, and a performance evaluation of the

1978-01-01

339

Performance of different tungsten grades under transient thermal loads  

NASA Astrophysics Data System (ADS)

Plasma facing components in future thermonuclear fusion devices will be subjected to intense transient thermal loads due to type I edge localized modes (ELMs), plasma disruptions, etc. To exclude irreversible damage to the divertor targets, local energy deposition must remain below the damage threshold for the selected wall materials. For monolithic tungsten (pure tungsten and tungsten alloys) power densities above ?0.3 GW m-2 with 1 ms duration result in the formation of a dense crack network. Thin tungsten coatings for the so-called ITER-like wall in JET, which have been deposited on a two-directional carbon-fibre composite (CFC) material, are even less resistant to thermal shock damage; here the threshold values are by a factor of 2 lower. First ELM-simulation experiments with high cycle numbers up to 104 cycles on actively cooled bulk tungsten targets do not reveal any cracks for absorbed power densities up to 0.2 GW m-2 and ELM-durations in the sub-millisecond range (0.8 ms); at somewhat higher power densities (0.27 GW m-2, ?t = 0.5 ms) cracks have been detected for 106 cycles.

Linke, J.; Loewenhoff, T.; Massaut, V.; Pintsuk, G.; Ritz, G.; Rödig, M.; Schmidt, A.; Thomser, C.; Uytdenhouwen, I.; Vasechko, V.; Wirtz, M.

2011-07-01

340

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

E-print Network

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 ...

Bartovics, William A

1984-01-01

341

Antenna performance predictions of a radio telescope subject to thermal perturbations  

E-print Network

Antenna performance predictions and calibration times are estimated on a 37 m diameter radio telescope subject to thermal perturbations. The telescope is designed to operate at frequencies up to 325 GHz with a one-way ...

Doyle, Keith B.

342

Understanding the performance characteristics of phase-change thermal interface materials  

Microsoft Academic Search

To aid in the understanding of phase-change thermal interface materials, the results of characterization testing performed on three currently available materials are discussed. These tests were performed using the methods of ASTM D 5470 modified to account for the properties of phase-change materials. These data reveal that while the materials tested show a variation in performance, they all achieve their

Bob Rauch

2000-01-01

343

Estimating static performance parameters of thermal imaging system based on image quality evaluation  

Microsoft Academic Search

Thermal imaging system is a kind of equipment that is widely used, its static performance parameters are always measured in library. The paper comes up with a new method to estimate the static performance parameters based on image quality evaluation, which can more easily and more quickly to compare performance of two instruments.

Chun-mei Xu; Yue-feng Wang; Wei Dong; Wei Zhang; Gang Li

2005-01-01

344

Faced with rising fuel costs, building and home owners are looking for energy-efficient solutions. Improving the building envelope (roof or attic system, walls,  

E-print Network

of roofing systems. · Collaborating with CertainTeed Corporation, ORNL helped define the benefits of a novel water resistive barrier material that exhibits variable performance attributes depending on its collaborations with industry (cool roofs, air barriers, insulation systems) resulting in affordable, moisture

Oak Ridge National Laboratory

345

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

346

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

NASA Technical Reports Server (NTRS)

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.

Parrish, Keith

1999-01-01

347

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

Microsoft Academic Search

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

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

2009-01-01

348

The performance analysis of the Trough Concentrating Solar Photovoltaic\\/Thermal system  

Microsoft Academic Search

The electrical and thermal performance of a 2m2 Trough Concentrating Photovoltaic\\/Thermal (TCPV\\/T) system with an energy flux ratio 10.27 are characterized by experiments. A single crystalline silicon solar cell array, a polycrystalline silicon cell array, a Super cell array and a GaAs cell array are respectively used in the experiments. The experimental results show that the electrical performance of the

M. Li; G. L. Li; X. Ji; F. Yin; L. Xu

2011-01-01

349

Indoor test for thermal performance of the Sunmaster evacuated tube (liquid) solar collector  

NASA Technical Reports Server (NTRS)

The test procedures used to obtain the thermal performance data for a solar collector under simulated conditions are presented. Tests included a stagnation test, a time constant test, a thermal efficiency test, an incident angle modifier test, and a hot fill test. All tests were performed at ambient conditions and the transient effect and the incident angle effect on the collector were determined. The solar collector is a water working fluid type.

1979-01-01

350

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

PubMed

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

Lan, Li; Wargocki, Pawel; Lian, Zhiwei

2014-05-01

351

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

NASA Astrophysics Data System (ADS)

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".

Foray, Vincent; Gibert, Patricia; Desouhant, Emmanuel

2011-08-01

352

Thermal limitation of performance and biogeography in a free-ranging ectotherm: insights from accelerometry.  

PubMed

Theoretical and laboratory studies generally show that ectotherm performance increases with temperature to an optimum, and subsequently declines. Several physiological mechanisms probably shape thermal performance curves, but responses of free-ranging animals to temperature variation will represent a compromise between these mechanisms and ecological constraints. Thermal performance data from wild animals balancing physiology and ecology are rare, and this represents a hindrance for predicting population impacts of future temperature change. We used internally implanted accelerometers near the middle of a species' geographical distribution and gill-net catch data near the species' latitudinal extremes to quantify temperature-related activity levels of a wild predatory fish (Platycephalus fuscus). We examined our data in the context of established models of thermal performance, and the relationship between thermal performance thresholds and biogeography. Acceleration data approximated a thermal performance curve, with activity peaking at 23°C but declining rapidly at higher temperatures. Gill-net catch data displayed a similar trend, with a temperature-associated increase and decrease in catch rates in temperate and tropical regions, respectively. Extrapolated estimates of zero activity (CTmin and CTmax) from the accelerometers were similar to the minimum and maximum mean monthly water temperatures experienced at the southern and northern (respectively) limits of the species distribution, consistent with performance-limited biogeography in this species. These data highlight the fundamental influence of temperature on ectotherm performance, and how thermal performance limits may shape biogeography. Biologging approaches are rarely used to examine thermal performance curves in free-ranging animals, but these may be central to understanding the trade-offs between physiology and ecology that constrain species' biogeographies and determine the susceptibility of ectotherms to future increases in temperature. PMID:24948630

Gannon, Ruan; Taylor, Matthew D; Suthers, Iain M; Gray, Charles A; van der Meulen, Dylan E; Smith, James A; Payne, Nicholas L

2014-09-01

353

Analysis of the thermal performance of heat pipe radiators  

NASA Technical Reports Server (NTRS)

A comprehensive mathematical model and computational methodology are presented to obtain numerical solutions for the transient behavior of a heat pipe radiator in a space environment. The modeling is focused on a typical radiator panel having a long heat pipe at the center and two extended surfaces attached to opposing sides of the heat pipe shell in the condenser section. In the set of governing equations developed for the model, each region of the heat pipe - shell, liquid, and vapor - is thermally lumped to the extent possible, while the fin is lumped only in the direction normal to its surface. Convection is considered to be the only significant heat transfer mode in the vapor, and the evaporation and condensation velocity at the liquid-vapor interface is calculated from kinetic theory. A finite-difference numerical technique is used to predict the transient behavior of the entire radiator in response to changing loads.

Boo, J. H.; Hartley, J. G.

1990-01-01

354

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

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

355

Thermal design and performance of the balloon-borne large aperture submillimeter telescope for polarimetry BLASTPol  

NASA Astrophysics Data System (ADS)

We present the thermal model of the Balloon-borne Large-Aperture Submillimeter Telescope for Polarimetry (BLASTPol). This instrument was successfully own in two circumpolar flights from McMurdo, Antarctica in 2010 and 2012. During these two flights, BLASTPol obtained unprecedented information about the magnetic field in molecular clouds through the measurement of the polarized thermal emission of interstellar dust grains. The thermal design of the experiment addresses the stability and control of the payload necessary for this kind of measurement. We describe the thermal modeling of the payload including the sun-shielding strategy. We present the in-flight thermal performance of the instrument and compare the predictions of the model with the temperatures registered during the flight. We describe the difficulties of modeling the thermal behavior of the balloon-borne platform and establish landmarks that can be used in the design of future balloon-borne instruments.

Soler, J. D.; Ade, P. A. R.; Angilè, F. E.; Benton, S. J.; Devlin, M. J.; Dober, B.; Fissel, L. M.; Fukui, Y.; Galitzki, N.; Gandilo, N. N.; Klein, J.; Korotkov, A. L.; Matthews, T. G.; Moncelsi, L.; Mroczkowski, A.; Netterfield, C. B.; Novak, G.; Nutter, D.; Pascale, E.; Poidevin, F.; Savini, G.; Scott, D.; Shariff, Jamil A.; Thomas, N. E.; Truch, M. D.; Tucker, C. E.; Tucker, G. S.; Ward-Thompson, D.

2014-07-01

356

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

NASA Technical Reports Server (NTRS)

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 utilized to investigate the solution options and guide the hardware modification decisions. Details related to test data interpretation, analytical uncertainties, and model-prediction vs. test-data correlation, are documented. Instrument/spacecraft interface issues, where the problem originated and where in general pitfalls abound, are dealt with specifically. Finally, on-orbit thermal performance data are presented, which exhibit good agreement with flight predictions, and lessons learned are discussed.

Lin, Edward I.

1993-01-01

357

Status of cool roof standards in the United States  

SciTech Connect

Since 1999, several widely used building energy efficiency standards, including ASHRAE 90.1, ASHRAE 90.2, the International Energy Conservation Code, and California's Title 24 have adopted cool roof credits or requirements. We review the technical development of cool roof provisions in the ASHRAE 90.1, ASHRAE 90.2, and California Title 24 standards, and discuss the treatment of cool roofs in other standards and energy-efficiency programs. The techniques used to develop the ASHRAE and Title 24 cool roof provisions can be used as models to address cool roofs in building energy standards worldwide.

Akbari, Hashem; Levinson, Ronnen

2007-06-01

358

Thermal and Mechanical Performance of a Carbon/Carbon Composite Spacecraft Radiator  

NASA Technical Reports Server (NTRS)

Carbon-carbon composite materials offer greater thermal efficiency, stiffness to weight ratio, tailorability, and dimensional stability than aluminum. These lightweight thermal materials could significantly reduce the overall costs associated with satellite thermal control and weight. However, the high cost and long lead-time for carbon-carbon manufacture have limited their widespread usage. Consequently, an informal partnership between government and industrial personnel called the Carbon-Carbon Spacecraft Radiator Partnership (CSRP) was created to foster carbon-carbon composite use for thermally and structurally demanding space radiator applications. The first CSRP flight opportunity is on the New Millennium Program (NMP) Earth Orbiter-1 (EO-1) spacecraft, scheduled for launch in late 1999. For EO-1, the CSRP designed and fabricated a Carbon-Carbon Radiator (CCR) with carbon-carbon facesheets and aluminum honeycomb core, which will also serve as a structural shear panel. While carbon-carbon is an ideal thermal candidate for spacecraft radiators, in practice there are technical challenges that may compromise performance. In this work, the thermal and mechanical performance of the EO-1 CCR is assessed by analysis and testing. Both then-nal and mechanical analyses were conducted to predict the radiator response to anticipated launch and on-orbit loads. The thermal model developed was based on thermal balance test conditions. The thermal analysis was performed using SINDA version 4.0. Structural finite element modeling and analysis were performed using SDRC/1-DEAS and UAI/NASTRAN, respectively. In addition, the CCR was subjected to flight qualification thermal/vacuum and vibration tests. The panel meets or exceeds the requirements for space flight and demonstrates promise for future satellite missions.

Kuhn, Jonathan; Benner, Steve; Butler, Dan; Silk, Eric

1999-01-01

359

CAVERN ROOF STABILITY FOR NATURAL GAS STORAGE IN BEDDED SALT  

SciTech Connect

This report documents research performed to develop a new stress-based criterion for predicting the onset of damage in salt formations surrounding natural gas storage caverns. Laboratory tests were conducted to investigate the effects of shear stress, mean stress, pore pressure, temperature, and Lode angle on the strength and creep characteristics of salt. The laboratory test data were used in the development of the new criterion. The laboratory results indicate that the strength of salt strongly depends on the mean stress and Lode angle. The strength of the salt does not appear to be sensitive to temperature. Pore pressure effects were not readily apparent until a significant level of damage was induced and the permeability was increased to allow penetration of the liquid permeant. Utilizing the new criterion, numerical simulations were used to estimate the minimum allowable gas pressure for hypothetical storage caverns located in a bedded salt formation. The simulations performed illustrate the influence that cavern roof span, depth, roof salt thickness, shale thickness, and shale stiffness have on the allowable operating pressure range. Interestingly, comparison of predictions using the new criterion with that of a commonly used criterion indicate that lower minimum gas pressures may be allowed for caverns at shallow depths. However, as cavern depth is increased, less conservative estimates for minimum gas pressure were determined by the new criterion.

Kerry L. DeVries; Kirby D. Mellegard; Gary D. Callahan; William M. Goodman

2005-06-01

360

Heat transfer in a large triangular-roof enclosure based on the second law analysis  

NASA Astrophysics Data System (ADS)

Application of entropy generation minimization method for the optimization of natural convection in triangular-roof enclosures can be helpful in enhancing the thermodynamic efficiency of the system. In this paper, the numerical solution of the entropy production was performed due to natural convection of laminar air flow in a large isosceles triangular-roof enclosure with different boundary conditions such as the greenhouses conjugate boundary conditions. The simulation results showed that the entropy generation number in an enclosure with partially heated from bottom wall center, is less than an enclosure with partially heated from bottom wall corner. Also, in a large triangular-roof greenhouse, the entropy generation number decreases with increasing of the greenhouse aspect ratio (L/H).

Ziapour, Behrooz M.; Dehnavi, Resam

2014-11-01

361

Reclaimed manufacturer asphalt roofing shingles in asphalt mixtures. Final research report  

SciTech Connect

The purpose of this project was to pave a test section using hot mix asphalt with roofing shingle pieces in the wearing and binder courses and to evaluate. The test project near Allentown, PA plus two other test projects in 1998 provide evidence of very good pavement performance. The bituminous concrete mix was modified with shredded shingles with a maximum size of 1/2 inch which added 1% of the asphalt content. The Department issued a statewide Provisional Specification titled Reclaimed Manufacturer Asphalt Roofing Shingles in Plant-Mixed Bituminous Concrete Courses'' on March 15, 1999. New manufacturer asphalt roofing shingle scrap including tab punch-outs can be successfully incorporated in bituminous concrete pavements if the shingles are shredded to 100% passing the 3/4 inch sieve. To take full advantage of the potential to replace a portion of the asphalt and therefore, reduce mix costs, shingles should be shredded to 100% passing minus 1/2 inch sieve.

Reed, A.B.

1999-04-23

362

Performance evaluation of solar thermal electric generation systems  

Microsoft Academic Search

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

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

2003-01-01

363

On the thermal performance of perforated heat exchanger plates  

SciTech Connect

This paper presents heat transfer characteristics of perforated copper plates for use in regenerators at low Reynolds number flow. A simple experimental system is described for quick evaluation of heat transfer performance. A simple theoretical model is used for evaluation of heat transfer coefficient from transient single blow experiments of low Biot number perforated single plate systems.

Ravikumar, K.V.; Frederking, T.H.K. [Univ. of California, Los Angeles, CA (United States)

1994-12-31

364

Planck early results. II. The thermal performance of Planck  

Microsoft Academic Search

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

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

365

Structural-thermal-optical performance (STOP) sensitivity analysis for the James Webb Space Telescope  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) is a key component of NASA's Origins Program to understand the origins and future of the universe. JWST will be used to study the birth and formation of galaxies and planets. The mission requires a large (25m2 aperture) but extremely stable (150 nm RMS wave front error) optical platform, where performance is a tightly coupled function of numerous physical processes. Distortion due to thermal loading is a significant error source. The process by which predicted heat loads are mapped to optical error is termed Structural-Thermal-Optical Performance (STOP) modeling. Thermal-optical performance is a function of heat loads, thermal properties (conductivities, radiative coupling coefficients), structural properties (moduli, geometry, thermal expansion coefficients, ply layup angles), and optical sensitivities. Sensitivities, the gradients of performance with respect to design parameters, give a direct way to identify the parameters that have the largest influence on performance. Additionally, gradients can identify the largest sources of uncertainty, and thus contribute to improving the robustness of the design, either via redesign or by placing requirements on parameter variability. The paper presents a general framework for developing the analytical sensitivities of the STOP prediction using the Chain Rule. The paper focuses on solving for the sensitivities of the steady-state, conduction-only, problem, using discipline modeling tools (thermal, structural, and optical) to compute the terms in the STOP gradients. The process is demonstrated on the SDR2 Rev. 1 cycle of the JWST modeling effort.

Blaurock, Carl; McGinnis, Mark; Kim, Kevin; Mosier, Gary E.

2005-09-01

366

Performance assessment of low pressure nuclear thermal propulsion  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

367

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...

368

Generalized roof duality and bisubmodular functions  

E-print Network

Consider a convex relaxation $\\hat f$ of a pseudo-boolean function $f$. We say that the relaxation is {\\em totally half-integral} if $\\hat f(\\bx)$ is a polyhedral function with half-integral extreme points $\\bx$, and this property is preserved after adding an arbitrary combination of constraints of the form $x_i=x_j$, $x_i=1-x_j$, and $x_i=\\gamma$ where $\\gamma\\in\\{0, 1, 1/2}$ is a constant. A well-known example is the {\\em roof duality} relaxation for quadratic pseudo-boolean functions $f$. We argue that total half-integrality is a natural requirement for generalizations of roof duality to arbitrary pseudo-boolean functions. Our contributions are as follows. First, we provide a complete characterization of totally half-integral relaxations $\\hat f$ by establishing a one-to-one correspondence with {\\em bisubmodular functions}. Second, we give a new characterization of bisubmodular functions. Finally, we show some relationships between general totally half-integral relaxations and relaxations based on the roof...

Kolmogorov, Vladimir

2010-01-01

369

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

SciTech Connect

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.

Ridouane, E. H.; Bianchi, M.

2011-11-01

370

Air versus liquid-based solar-energy systems: A comparison of measured thermal performances  

Microsoft Academic Search

A comparison of the thermal performance of five liquid based solar energy systems to five air based solar energy systems is presented. Data for each of these ten sites was collected and converted to uniformly defined performance factors. The ten sites are all single family residences using solar energy to supply part of the space and water heating loads. Each

D. R. Patterson

1983-01-01

371

An estimation of the performance limits and improvement of dry cooling on trough solar thermal plants  

Microsoft Academic Search

A study is reported of the potential performance of dry cooling on power generation. This is done in the context of a generic trough solar thermal power plant. The commercial power plant analysis code GateCycle is applied for this purpose. This code is used to estimate typical performance of both wet and dry cooling options. Then it is configured to

Huifang Deng; Robert F. Boehm

2011-01-01

372

Predicting the thermal/structural performance of the atmospheric trace molecules spectroscopy /ATMOS/ Fourier transform spectrometer  

NASA Technical Reports Server (NTRS)

ATMOS is a Fourier transform spectrometer to measure atmospheric trace molecules over a spectral range of 2-16 microns. Assessment of the system performance of ATMOS includes evaluations of optical system errors induced by thermal and structural effects. In order to assess the optical system errors induced from thermal and structural effects, error budgets are assembled during system engineering tasks and line of sight and wavefront deformations predictions (using operational thermal and vibration environments and computer models) are subsequently compared to the error budgets. This paper discusses the thermal/structural error budgets, modelling and analysis methods used to predict thermal/structural induced errors and the comparisons that show that predictions are within the error budgets.

Miller, J. M.

1980-01-01

373

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

374

Thermal performance of thermoelectric cooler (tec) integrated heat sink and optimizing structure for low acoustic noise \\/ power consumption  

Microsoft Academic Search

In this paper, authors are proposing the idea of applying thermoelectric cooler (TEC) to CPU cooling. The proposed cooling system is a no moving parts apparatus that can improve thermal performance by keeping same form factor. This system will accommodate an increase in the CPU thermal design power and\\/or lower the noise of the cooling solution. The thermal performance of

M. Ikeda; T. Nakamura; Y. Kimura; H. Noda; I. Sauciuc; H. Erturk

2006-01-01

375

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

E-print Network

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

Kandlikar, Satish

376

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

NASA Technical Reports Server (NTRS)

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.

Cao, Y.; Faghri, A.

1991-01-01

377

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

Microsoft Academic Search

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

M. R. E. Looyeh; P. Bettess

1998-01-01

378

Effects of lithium phosphorous oxynitride film coating on electrochemical performance and thermal stability of graphite anodes  

Microsoft Academic Search

In this study, we investigated the effects of lithium phosphorus oxynitride (LiPON) solid electrolyte thin-film deposition on the electrochemical performance and thermal stability of pristine graphite and carbon-coated graphite composite anodes. The LiPON film was deposited by radio frequency (rf) magnetron sputtering. We studied the thermal stability of the lithiated electrodes when immersed in the presence of a liquid electrolyte

Yoon-Soo Park; Sung-Man Lee

2011-01-01

379

Performance analysis of photovoltaic-thermal collector by explicit dynamic model  

Microsoft Academic Search

Although the performance of hybrid photovoltaic-thermal (PV\\/T) collector had been studied both experimentally and numerically for some years, the thermal models developed in previous studies were mostly steady-state models for predicting the annual yields. The operation of a PV\\/T collector is inherently dynamic. A steady-state model is not suitable for predicting working temperatures of the PV module and the heat-removal

T. T. Chow

2003-01-01

380

Effects of Framing on the Thermal Performance of Wood and Steel-Framed Walls  

E-print Network

imperfections. Keywords R-value, Framing Factor, Cavity Insulation, Framing Effect Coefficient, Steel Frame walls, Wood-frame walls TERMINOLOGY OF THE WHOLE WALL R-VALUE PROCEDURE USED IN THIS PAPER The following list of thermal performance... Code (IECC), and Title 24 of the California Energy Commission (CEC) contain the insulation standards for buildings [6, 7, 8, 9]. For thermal calculations, the ASHRAE Handbook of Fundamentals [10] recommends using the parallel-path method for wood...

Kosny, J.; Yarbrough, D. W.; Childs, P.; Mohiuddin, S. A.

2006-01-01

381

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

NASA Technical Reports Server (NTRS)

A thermal interface material is one of the many tools 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.

Glasgow, Shaun; Kittredge, Ken

2003-01-01

382

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

NASA Technical Reports Server (NTRS)

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.

Leonhard, K. E.

1975-01-01

383

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

384

Characterization of Hollow Cathode Performance and Thermal Behavior  

NASA Technical Reports Server (NTRS)

Hollow cathodes are one of the main life-limiting components in ion engines and Hall thrusters. Although state-of-the-art hollow cathodes have demonstrated up to 30,352 hours of operation in ground tests with careful handling, future missions are likely to require longer life, more margin and greater resistance to reactive contaminant gases. Three alternate hollow cathode technologies that exploit different emitter materials or geometries to address some of the limitations of state-of-the-art cathodes are being investigated. Performance measurements of impregnated tungsten-iridium dispenser cathodes at discharge currents of 4 to 15 A demonstrated that they have the same operating range and ion production efficiency as conventional tungsten dispenser cathodes. Temperature measurements indicated that tungsten-iridium cathodes also operate at the same emitter temperatures. They did not exhibit the expected reduction in work function at the current densities tested. Hollow cathodes with lanthanum hexaboride emitters operated over a wide current range, but suffered from lower ion production efficiency at currents below about 12.4 A because of higher insert heating requirements. Differences in operating voltages and ion production rates are explained with a simple model of the effect of cathode parameters on discharge behavior.

Polk, James E.; Goebel, Dan M.; Watkins, Ron; Jameson, Kristina; Yoneshige, Lance; Przybylowski, JoHanna; Cho, Lauren

2006-01-01

385

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

SciTech Connect

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.

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

386

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

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).

I. E. Sumner

1978-01-01

387

Performance study of solar cell arrays based on a Trough Concentrating Photovoltaic\\/Thermal system  

Microsoft Academic Search

The performances of solar cell arrays based on a Trough Concentrating Photovoltaic\\/Thermal (TCPV\\/T) system have been studied via both experiment and theoretical calculation. The I–V characteristics of the solar cell arrays and the output performances of the TCPV\\/T system demonstrated that among the investigated four types of solar cell arrays, the triple junction GaAs cells possessed good performance characteristics and

Ming Li; Xu Ji; Guoliang Li; Shengxian Wei; YingFeng Li; Feng Shi

2011-01-01

388

Thermal performance of a mechanically attached ablator tile for on-orbit repair of shuttle TPS  

NASA Technical Reports Server (NTRS)

The reusable surface insulation (RSI) material used in the shuttle thermal protection system is susceptible to damage. If any RSI tiles are damaged or lost during ascent, they must be repaired or replaced prior to entry. One approach to replacing a damaged or missing RSI tile consists of mechanically attaching a tile of ablation material in the place of the RSI tile. The thermal performance of this type of repair tile was evaluated in a simulated entry heating environment. The test specimen consisted of the ablator repair tile mechanically fastened to the strain isolation pad and surrounded by RSI tiles. The evaluation of the thermal performance was based on temperature response, surface integrity, and predicted flight performance. When the ablator tile protruded 1/8 inch above the surrounding RSI tiles, the forward facing steps caused significant inflow of hot gas down the ablator RSI joints and this inflow caused greatly increased back surface temperatures.

Thompkins, S. S.; Pittman, C. M.; Stacey, A. B., Jr.

1980-01-01

389

Does the thermal plasticity of metabolic enzymes underlie thermal compensation of locomotor performance in the eastern newt (Notophthalmus viridescens)?  

PubMed

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

Mineo, Patrick M; Schaeffer, Paul J

2015-01-01

390

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

NASA Technical Reports Server (NTRS)

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 the size of the collector field and energy storage subsystem for given engine generator and energy transport characteristics. The development of the simulation tool, its operation, and the results achieved from the analysis are discussed.

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

1981-01-01

391

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)

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.

Sumner, I. E.

1978-01-01

392

Comparison of Thermal Performance Characteristics of Ammonia and Propylene Loop Heat Pipes  

NASA Technical Reports Server (NTRS)

In this paper, experimental work performed on a breadboard Loop Heat Pipe (LHP) is presented. The test article was built by DCI for the Geoscience Laser Altimeter System (GLAS) instrument on the ICESat spacecraft. The thermal system requirements of GLAS have shown that ammonia cannot be used as the working fluid in this LHP because GLAS radiators could cool to well below the freezing point of ammonia. As a result, propylene was proposed as an alternative LHP working fluid since it has a lower freezing point than ammonia. Both working fluids were tested in the same LHP following a similar test plan in ambient conditions. The thermal performance characteristics of ammonia and propylene LHP's were then compared. In general, the propylene LHP required slightly less startup superheat 5nd less control heater power than the ammonia LHP, The thermal conductance values for the propylene LHP were also lower than the ammonia LHP. Later, the propylene LHP was tested in a thermal vacuum chamber. These tests demonstrated that propylene could meet the GLAS thermal design requirements. Design guidelines were proposed for the next flight-like Development Model (DM) LHP for thermal control of the GLAS instrument.

Kaya, Tarik; Baker, Charles; Ku, Jentung

2000-01-01

393

Geographic variation in thermal physiological performance of the intertidal crab Petrolisthes violaceus along a latitudinal gradient.  

PubMed

Environmental temperature has profound effects on the biological performance and biogeographical distribution of ectothermic species. Variation of this abiotic factor across geographic gradients is expected to produce physiological differentiation and local adaptation of natural populations depending on their thermal tolerances and physiological sensitivities. Here, we studied geographic variation in whole-organism thermal physiology of seven populations of the porcelain crab Petrolisthes violaceus across a latitudinal gradient of 3000 km, characterized by a cline of thermal conditions. Our study found that populations of P. violaceus show no differences in the limits of their thermal performance curves and demonstrate a negative correlation of their optimal temperatures with latitude. Additionally, our findings show that high-latitude populations of P. violaceus exhibit broader thermal tolerances, which is consistent with the climatic variability hypothesis. Interestingly, under a future scenario of warming oceans, the thermal safety margins of P. violaceus indicate that lower latitude populations can physiologically tolerate the ocean-warming scenarios projected by the IPCC for the end of the twenty-first century. PMID:25394627

Gaitán-Espitia, Juan Diego; Bacigalupe, Leonardo D; Opitz, Tania; Lagos, Nelson A; Timmermann, Tania; Lardies, Marco A

2014-12-15

394

71. Joe Moore, Photographer. September, 1996. BEVATRON ROOF SHIELDING AND ...  

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

71. Joe Moore, Photographer. September, 1996. BEVATRON ROOF SHIELDING AND BUILDING TRUSS STRUCTURE - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

395

Cool roofs as an energy conservation measure for federal buildings  

SciTech Connect

We have developed initial estimates of the potential benefits of cool roofs on federal buildings and facilities (building scale) as well as extrapolated the results to all national facilities under the administration of the Federal Energy Management Program (FEMP). In addition, a spreadsheet ''calculator'' is devised to help FEMP estimate potential energy and cost savings of cool roof projects. Based on calculations for an average insulation level of R-11 for roofs, it is estimated that nationwide annual savings in energy costs will amount to $16M and $32M for two scenarios of increased roof albedo (moderate and high increases), respectively. These savings, corresponding to about 3.8 percent and 7.5 percent of the base energy costs for FEMP facilities, include the increased heating energy use (penalties) in winter. To keep the cost of conserved energy (CCE) under $0.08 kWh-1 as a nationwide average, the calculations suggest that the incremental cost for cool roofs should not exceed $0.06 ft-2, assuming that cool roofs have the same life span as their non-cool counterparts. However, cool roofs usually have extended life spans, e.g., 15-30 years versus 10 years for conventional roofs, and if the costs of re-roofing are also factored in, the cutoff incremental cost to keep CCE under $0.08 kWh-1 can be much higher. In between these two ends, there is of course a range of various combinations and options.

Taha, Haider; Akbari, Hashem

2003-04-07

396

5. VIEW OF VENTILATION HOUSES AND ROOF MONITOR FROM SOUTHEAST ...  

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

5. VIEW OF VENTILATION HOUSES AND ROOF MONITOR FROM SOUTHEAST CORNER OF ROOF. ROOF MONITOR WINDOWS HAVE BEEN INFILLED WITH BRICK. THE VENTILATION HOUSES ARE PART OF THE ORIGINAL CENTRAL AIR CONDITIONING SYSTEM AND CONTAINED AIR WASHERS, FANS AND OTHER HUMIDFYING EQUIPMENT FROM PARKS-CRAMER COMPANY OF FITCHBURG, MASSACHUSETTS. LOCATING THIS EQUIPMENT ON THE ROOF MADE IT UNNECESSARY TO CONSTRUCT A FULL BASEMENT, AND THEREFORE LOWERED CONSTRUCTION COSTS. THIS ARRANGEMENT ALSO PUT THE AIR CONDITIONING EQUIPMENT CLOSEST TO THE TOP FLOOR SPINNING ROOM, WHICH HAD THE GREATEST COOLING REQUIREMENTS. - Stark Mill, 117 Corinth Road, Hogansville, Troup County, GA

397

Solder-Graphite Network Composite Sheets as High-Performance Thermal Interface Materials  

NASA Astrophysics Data System (ADS)

Low-cost solder-graphite composite sheets (?55 vol.% solder), with solder and graphite forming interpenetrating networks to a degree, are excellent thermal interface materials (TIMs). Solders 63Sn-37Pb and 95.5Sn-4Ag-0.5Cu are separately used, with the latter performing better. In composite fabrication, a mixture of micrometer-size solder powder and ozone-treated exfoliated graphite is compressed to form a graphite network, followed by fluxless solder reflow and subsequent hot pressing to form the solder network. The network connectivity (enhanced by ozone treatment) is lower in the through-thickness direction. The electrical conductivity obeys the rule of mixtures (parallel model in-plane and series model through-thickness), with anisotropy 7. Thermal contact conductance ?26 × 104 W/(m2 K) (with 15-?m-roughness copper sandwiching surfaces), through-thickness thermal conductivity ?52 W/(m K), and in-plane thermal expansion coefficient 1 × 10-5/°C are obtained. The contact conductance exceeds or is comparable to that of all other TIMs, provided that solder reflow has occurred and the composite thickness is ?100 ?m. Upon decreasing the thickness below 100 ?m, the sandwich thermal resistivity decreases abruptly, the composite through-thickness thermal conductivity increases abruptly to values comparable to the calculated values based on the rule of mixtures (parallel model), and the composite-copper interfacial thermal resistivity (rather than the composite resistivity) becomes dominant.

Sharma, Munish; Chung, D. D. L.

2015-01-01

398

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

NASA Astrophysics Data System (ADS)

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

Christian, J.

1984-06-01

399

Thermal Performance of Cryogenic Piping Multilayer Insulation in Actual Field Installations  

NASA Technical Reports Server (NTRS)

A standardized way of comparing the thermal performance of different pipelines in different sizes is needed. Vendor data for vacuum-insulated piping are typically given in heat leak rate per unit length (W/m) for a specific diameter pipeline. An overall k-value for actual field installations (k(sub oafi)) is therefore proposed as a more generalized measure for thermal performance comparison and design calculation. The k(sub oafi) provides a direct correspondence to the k-values reported for insulation materials and illustrates the large difference between ideal multilayer insulation (MLI) and actual MLI performance. In this experimental research study, a section of insulated piping was tested under cryogenic vacuum conditions, including simulated spacers and bending. Several different insulation systems were tested using a 1-meter-long cylindrical cryostat test apparatus. The simulated spacers tests showed significant degradation in the thermal performance of a given insulation system. An 18-meter-long pipeline test apparatus is now in operation at the Cryogenics Test Laboratory, NASA Kennedy Space Center, for conducting liquid nitrogen thermal performance tests.

Fesmire, J.; Augustnynowicz, S.; Thompson, K. (Technical Monitor)

2002-01-01

400

Methodology for comparison of hydraulic and thermal performance of alternative heat transfer fluids in complex systems  

SciTech Connect

A general method for the comparison of hydraulic and thermal performance of different liquid coolants in complex systems is offered. As a case study, the performance of polyalphaolefin (PAO) and a silicate ester-based fluid (Coolanol 25R) used as liquid coolants in avionic systems is presented. Thermophysical property expressions for the variation of density, specific heat, thermal conductivity, and kinematic viscosity with temperature for PAO and Coolanol 25R were developed. The range of temperature for this study was from {minus}54 to 135 C. Based on the results, the hydraulic performance of Coolanol 25R is much better than that of PAO at low temperatures (below 0 C) and in the laminar flow regime. In the turbulent region, PAO outperforms Coolanol 25R hydraulically over the entire temperature range. The thermal performance of PAO at temperatures below 61 C and in the laminar flow region is slightly better than that of Coolanol 25R. In the low-temperature turbulent region, Coolanol 25R outperforms PAO thermally. At other temperatures, the performance of the two liquid coolants is reasonably close and fairly independent of the flow regime.

Ghajar, A.J.; Tang, W.C. [Oklahoma State Univ., Stillwater, OK (United States). School of Mechanical and Aerospace Engineering; Beam, J.E. [Power Technology Branch, Wright Patterson AFB, OH (United States). Thermal Technology Section

1995-01-01

401

Final Design and Experimental Validation of the Thermal Performance of the LHC Lattice Cryostats  

E-print Network

The recent commissioning and operation of the LHC String 2 have given a first experimental validation of the global thermal performance of the LHC lattice cryostat at nominal cryogenic conditions. The cryostat designed to minimize the heat inleak from ambient temperature, houses under vacuum and thermally protects the cold mass, which contains the LHC twin-aperture superconducting magnets operating at 1.9 K in superfluid helium. Mechanical components linking the cold mass to the vacuum vessel, such as support posts and insulation vacuum barriers are designed with efficient thermalisations for heat interception to minimise heat conduction. Heat inleak by radiation is reduced by employing multilayer insulation (MLI) wrapped around the cold mass and around an aluminium thermal shield cooled to about 60 K. Measurements of the total helium vaporization rate in String 2 gives, after substraction of supplementary heat loads and end effects, an estimate of the total thermal load to a standard LHC cell (107 m) includi...

Bourcey, N; Parma, V; Poncet, A; Rohmig, P; Serio, L; Skoczen, Blazej; Tock, J P; Williams, L R

2004-01-01

402

A review of the combined effects of thermal and noise conditions on human performance  

NASA Astrophysics Data System (ADS)

Human perception and annoyance due to background noise has been the subject of much research. A great deal of work has also been done to identify conditions that produce an acceptable thermal environment for building occupants. The experience of occupants in indoor environments, however, is much more complex than can be represented by thermal comfort or the acoustic environment in isolation. Occupants normally experience a mix of thermal, auditory, visual, and olfactory stimuli that combines to form an impression of the environment. This paper is specifically interested in how building occupants trade off between acoustic and thermal comfort. Heating, ventilation, and air-conditioning systems in buildings are often adjusted by building users to arrive at a more comfortable temperature, but this change may also produce more noise. Previous studies on the interaction effects between temperature and noise on human performance are reviewed in this presentation, followed by a discussion of the authors' current work in this area.

Moscoso, Richard A.; Wang, Lily M.; Musser, Amy

2001-05-01

403

Construct and Test Roofs for Different Climates  

NSDL National Science Digital Library

We design and create objects to make our lives easier and more comfortable. The houses in which we live are excellent examples of this. Depending on your local climate, the features of your house have been designed to satisfy your particular environmental needs: protection from hot, cold, windy and/or rainy weather. In this activity, students design and build model houses, then test them against various climate elements, and then re-design and improve them. Using books, websites and photos, students learn about the different types of roofs found on various houses in different environments throughout the world.

Center For Engineering Educational Outreach

404

THE EVERGREEN ROOF PROJECT: STANDARDS, METHODS AND SOFTWARE FOR EVALUATING LIVING ROOF SYSTEMS  

EPA Science Inventory

The Evergreen Roof Project set out four objectives for Phase I of our project and has made sufficient progress on all of those objectives to qualify this phase as a success. Through an extensive literature review and discussions with researchers, designers, inst...

405

Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater  

PubMed Central

The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s?1. Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s?1 with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency.

Chabane, Foued; Moummi, Noureddine; Benramache, Said

2013-01-01

406

Thermal flow monitor: Design and performance in acid rain stacks 1991--1994  

SciTech Connect

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.

Groce, P.J. [Kurz Instruments, Inc., Monterey, CA (United States)

1995-12-31

407

Cryogenic Thermal Performance Testing of Bulk-Fill and Aerogel Insulation Materials  

NASA Technical Reports Server (NTRS)

The research testing and demonstration of new bulk-fill materials for cryogenic thermal insulation systems was performed by the Cryogenics Test Laboratory at NASA Kennedy Space Center. Thermal conductivity testing under actual-use cryogenic conditions is a key to understanding the total system performance encompassing engineering, economics, and materials factors. A number of bulk fill insulation materials, including aerogel beads, glass bubbles, and perlite powder, were tested using a new cylindrical cryostat. Boundary temperatures for the liquid nitrogen boil-off method were 293 K and 78 K. Tests were performed as a function of cold vacuum pressure from high vacuum to no vacuum conditions. Results are compared with other complementary test methods in the range of 300 K to 20 K. Various testing techniques are shown to be required to obtain a complete understanding of the operating performance of a material and to provide data for answers to design engineering questions.

Scholtens, B. E.; Fesmire, J. E.; Sass, J. P.; Augustynowicz, S. D.; Heckle, K. W.

2007-01-01

408

Thermal performance, economic and environmental life cycle analysis of thermosiphon solar water heaters  

Microsoft Academic Search

In this paper, the environmental benefits or renewable energy systems are initially presented followed by a study of the thermal performance, economics and environmental protection offered by thermosiphon solar water heating systems. The system investigated is of the domestic size, suitable to satisfy most of the hot water needs of a family of four persons. The results presented in this

Soteris Kalogirou

2009-01-01

409

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

Microsoft Academic Search

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

Y. Cao; A. Faghri

1991-01-01

410

Performance Analysis of Two-Stage Thermal Energy Storage System of Solar Power Tower Plant  

Microsoft Academic Search

Based on the principles of mass, energy conservation and state equation for ideal gas, operation performance of two-stage thermal energy storage system of the first 1MW solar tower power plant in China was calculated and analyzed using numerical simulation method. The results indicated that the pressure of nitrogen in oil tanks slightly changes as a function of temperature and volume

Jiayan Zhuang; Fengwu Bai; Ershu Xu

2011-01-01

411

Performance of thermal control tape in the protection of composite materials to space environmental exposure  

NASA Technical Reports Server (NTRS)

Thermal control tape flown on the Long Duration Exposure Facility (LDEF) experiment A0171 has shown to be effective in protecting epoxy fiberglass composites from atomic oxygen and ultraviolet degradation. The tape adhesive performed well. The aluminum, however, appeared to have become embrittled by the 5.8 years of space radiation exposure.

Kamenetzky, R. R.; Whitaker, A. F.

1992-01-01

412

THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER  

E-print Network

THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER Dennis L. Youchison-cooled, refractory heat exchangers are now under consideration for first wall and divertor applications-channel, helium-cooled heat exchanger made almost entirely of tungsten was designed and fabricated by Thermacore

California at Los Angeles, University of

413

Increasing Thermal Performance and Energy Efficiency of Buildings in Russia: Problems and Solutions  

Microsoft Academic Search

Over the past decade, a new generation of building energy codes has taken effect in Russia. These codes, which mandate a reduction of at least 40 percent in energy consumption for heating, have led to the need for an increase of 2.5 to 3 times in envelope thermal performance. Consequently, a fundamental transformation has taken place, toward the production, sale,

Yurij A. Matrosov; Mark Chao; Cliff Majersik

2008-01-01

414

Analysis and optimization of the thermal performance of microchannel heat sinks  

Microsoft Academic Search

Purpose – To provide modeling approaches of increasing levels of complexity for the analysis of convective heat transfer in microchannels which offer adequate descriptions of the thermal performance, while allowing easier manipulation of microchannel geometries for the purpose of design optimization of microchannel heat sinks. Design\\/methodology\\/approach – A detailed computational fluid dynamics model is first used to obtain baseline results

Dong Liu; Suresh V. Garimella

2005-01-01

415

Performance Analysis of Water and Power Cogeneration System with Thermal Vapor Compressor  

Microsoft Academic Search

The water and power cogeneration system with thermal vapor compressor (TVC) is studied in which condensing power plant provides extraction steam for the low-temperature multi-effect distillation desalination system (MED) with TVC as motive steam. The influence of the different position of both the secondary steam which is used as injection steam and the extraction steam of turbine on the performance

Yu Du; Xiaohua Liu; Shengqiang Shen; Wenbo Chen; Dawei Liu

2010-01-01

416

Thermal Performance of a Vapor Chamber Heat Pipe with Diamond-Copper Composition Wick Structures  

Microsoft Academic Search

The vapor chamber heat pipe has the potential in the challenging areas to be employed as a heat spreader for cooling of high-performance microchips. This is due to not only the thickness of vapor chamber is in order of mm scale but also both the weight and the thermal resistance are less than the conventional copper heat spreaders. The operation

Ying-Tung Chen; Jr-Ming Miao; Dau-Yuan Ning; Te-Feng Chu; Wei-En Chen

2009-01-01

417

Design space exploration for multicore architectures: a power\\/performance\\/thermal view  

Microsoft Academic Search

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

Matteo Monchiero; Ramon Canal; Antonio González

2006-01-01

418

A comparative performance study of some thermal storage materials used for solar space heating  

Microsoft Academic Search

One of the most common methods used in passive heating is the utilization of a massive wall for heat storage. Many factors affect the performance of the wall, such as the thickness and the media used for heat storage. A numerical study has been conducted on a zone heated by a thermal storage wall. Three different storage materials are examined,

Abdul Jabbar N. Khalifa; Ehsan F. Abbas

2009-01-01

419

Thermal and structural performance of GRP panels and short columns under fire conditions  

Microsoft Academic Search

This paper presents the results of an experimental study of the behaviour of different types of GRP structures under fire conditions. The experiments were conducted in two stages. The first part is concerned with the thermal performance of GRP sandwich panels and stringer systems when exposed to fire on one side. The objective of this study is to provide experimental

P. M. Currie; Yong Wang; J. M. Davies

2003-01-01

420

A slug calorimeter for evaluating the thermal performance of fire resistive materialsz  

Microsoft Academic Search

SUMMARY The utilization of a slug calorimeter to evaluate the thermal performance of fire resistive materials (FRMs) is presented. The basic specimen configuration consists of a 'sandwich', with a square central stainless-steel plate (slug) surrounded on two sides by the FRM. This sandwich configuration provides an adiabatic boundary condition at the central axis of the slug plate that greatly simplifies

D. P. Bentz; D. R. Flynn; J. H. Kim; R. R. Zarr

421

Flight Performance of an Advanced Thermal Protection Material: Toughened Uni-Piece Fibrous Insulation  

NASA Technical Reports Server (NTRS)

The flight performance of a new class of low density, high temperature thermal protection materials (TPM) is described and compared to "standard" Space Shuttle TPM. This new functionally gradient material designated as Toughened Uni-Piece Fibrous Insulation (TUFI), was bonded on a removable panel attached to the base heat shield of Orbiter 105, Endeavour.

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

1995-01-01

422

Flight Performance of an Advanced Thermal Protection Material: Toughened Uni-Piece Fibrous Insulation  

NASA Technical Reports Server (NTRS)

The flight performance of a new class of low density, high temperature, thermal protection materials (TPM), is described and compared to "standard" Space Shuttle TPM. This new functionally gradient material designated as Toughened Uni-Piece Fibrous Insulation (TUFI), was bonded on a removable panel attached to the base heatshield of Orbiter 105, Endeavor.

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

1995-01-01

423

PERFORMANCE OF NB{sub 3}SN QUADRUPOLE MAGNETS UNDER LOCALIZED THERMAL LOAD  

SciTech Connect

This paper describes the results of design and analyses performed on 120-mm Nb{sub 3}Sn and NbTi quadrupole magnets with parameters relevant for the LHC IR upgrade. A realistic radiation heat load is evaluated in a wide luminosity range and translated into the magnet quench performance. The simulation results are supported by thermal measurements on a 90-mm Nb{sub 3}Sn quadrupole coil.

Kashikhin, V. V.; Bossert, R.; Chlachidze, G.; Lamm, M.; Mokhov, N. V.; Novitski, I.; Zlobin, A. V. [Fermi National Accelerator Laboratory, Batavia, IL, 60510 (United States)

2010-04-09

424

Thermal performance of a compact evaporator coil in household refrigerator-freezers  

Microsoft Academic Search

A high-efficiency evaporator coil, which is placed horizontally between refrigerator and freezer compartments, for household\\u000a auto-defrost refrigerator-freezers has been developed. Several experiments were performed to investigate the thermal performance\\u000a of the newly developed compact evaporator coil in a 248l auto-defrost refrigerator-freezer and the results are compared with those of the conventional evaporator. The energy efficiency\\u000a of the system with newly

Man-Hoe Kim

1998-01-01

425

The steady-state thermal-hydraulic performance of 3500 MWth metal and oxide fueled LMRs  

SciTech Connect

The thermal-hydraulic performance of a 3500 MWth metal and oxide fueled LMR is reported. Orifice zones are defined and coolant flowrates are given for use in safety analyses. The flux calculations were carried out in three-dimensional hexagonal-Z geometry using a finite differenced diffusion theory code. The heating calculations included the transport and deposition of gamma energy. The assembly temperature calculations were performed using a subchannel code.

Vilim, R.B.; Hill, R.N.

1989-03-01

426

Improved thermal performance of a hydronic radiant panel heating system by the optimization of tube shapes  

Microsoft Academic Search

The thermal performance enhancement of the hydronic radiant floor heating system by tube shape refinements is investigated\\u000a in this paper. Both analytical and detailed numerical modelings are carried out to predict the performance of the radiant\\u000a system. While the simple analytical model briefly investigates the possibility of the effect of the tube shape improvement\\u000a with the parametric analysis, the commercial

Young T. Chae; Kwang Ho Lee; Jae Sung Park

2011-01-01

427

Zinc and copper in roof runoff.  

PubMed

The zinc and copper content of roof runoff could originate from different sources such as dry and wet deposition and the corrosion of the material. The zinc runoff rate from a galvanized surface depends on the corrosion products formed during the dry days, the rain intensity and roof slope, which determinates the contact time. In the present study the contact time dependence of zinc rate and the re-dissolution of the zinc were investigated with steeping tests and a pilot study. The average zinc runoff measured in the first 2.8 l of runoff was 3.8 mg m(-2) (1.1-8.4 mg m(-2)), while in the following samples 1.2 mg m(-2) were detected. These results are in accordance with the 5-10 min, and 40-60 s contact time laboratory steeping test, respectively, which are realistic. The estimated specific yearly zinc runoff rate was 0.7 g m(-2)y(-1), while the dry and wet deposition rate of copper was 0.009 mg m(-2)d(-1) and 0.053 mg m(-2)storm(-1) respectively. The re-dissolution of the zinc from the evaporated then re-filled samples of leaching tests with high initial zinc content was just 60% after 60 min. PMID:23579827

Horváth, A; Buzás, K

2013-01-01

428

Roof Bolting: Bolts from the blue  

SciTech Connect

Mechanization and subsequent automation of the roof support function are, as noted in studies of developments in underground excavation technology, critical steps in the development of more productive hard rock mining systems, whether these be based on drill-and-blast or continuous excavation systems. Overall, mechanized rock bolting is said to deliver consistency and reliability. The more specific advantages include: rapid, precise bolt installation; increased safety and less exposure to hazards for the roof bolting crew; areas that are high and difficult to access easily bolted by one man; precise control of bolt installation parameters; rapid execution of bolting operations, ensuring increased productivity and economy. However, achieving success with mechanized bolting is not simply a matter of placing an order for a machine. As the experiences of White Pine and Henderson testify, you need the right machine, the right type of bolt and anchoring system, the right size of bolt to get the right result in each specific set of mining conditions, and properly trained operators and maintenance people. This paper describes these procedures.

Casteel, K.

1993-12-01

429

Visual Analytics for Roof Savings Calculator Ensembles  

SciTech Connect

The Roof Savings Calculator (RSC) has been deployed for DOE as an industry-consensus, web-based tool for easily running complex building energy simulations. These simulations allow both homeowners and experts to determine building-specific cost and energy savings for modern roof and attic technologies. Using a database of over 3 million RSC simulations for different combinations of parameters, we have built a visual analytics tool to assist in the exploration and identification of features in the data. Since the database contains multiple variables, both categorical and continuous, we employ a coordinated multi-view approach that allows coordinated feature exploration through multiple visualizations at once. The main component of our system, a parallel coordinates view, has been adapted to handle large-scale, mixed data types as are found in RSC simulations. Other visualizations include map coordinated plots, high dynamic range (HDR) line plot rendering, and an intuitive user interface. We demonstrate these techniques with several use cases that have helped identify software and parametric simulation issues.

Jones, Chad [University of California, Davis] [University of California, Davis; New, Joshua Ryan [ORNL] [ORNL; Sanyal, Jibonananda [ORNL] [ORNL; Ma, Kwan-Liu [University of California, Davis] [University of California, Davis

2012-01-01

430

A Roof for the Lion's House  

NASA Technical Reports Server (NTRS)

Fans of the National Football League's Detroit Lions don't worry about gameday weather. Their magnificent new Pontiac Stadium has a domed, air-supported, fabric roof that admits light but protects the playing field and patrons from the elements. The 80,000-seat "Silverdome" is the world's largest fabric-covered structure-and aerospace technology played an important part in its construction. The key to economical construction of the Silverdome-and many other types of buildings-is a spinoff of fiber glass Beta yarn coated with Teflon TFE fluorocarbon resin. The big advance it offers is permanency. Fabric structures-tents, for example have been around since the earliest years of human civilization. But their coverings-hides, canvas and more recently plastics-were considered temporary; though tough, these fabrics were subject to weather deterioration. Teflon TFE-coated Beta Fiberglas is virtually impervious to the effects of weather and sunlight and it won't stretch, shrink, mildew or rot, thus has exceptional longevity; it is also very strong, lightweight, flame resistant and requires no periodic cleaning, because dirt will not stick to the surface of Teflon TFE. And to top all that, it costs only 30 to 40 percent as much as conventional roofing.

1978-01-01

431

Thermal performance of the FSEC PV house under closed conditions--blast predictions versus measurements  

Microsoft Academic Search

An energy efficient photovoltaic (PV) house has been constructed on the Florida Solar Energy Center (FSEC) in Cape Canaveral, Florida. The area of this PV house is 120.8 sq. m. (1300 sq. ft.) and it has three bedrooms and two baths. Although photovoltaic panels are installed on the south facing roof to meet a part of the house energy requirement,

M. A. Girgis; S. Chandra; M. Khattar

1983-01-01

432

Thermal design and performance of the REgolith x-ray imaging spectrometer (REXIS) instrument  

NASA Astrophysics Data System (ADS)

The REgolith X-ray Imaging Spectrometer (REXIS) instrument is a student collaboration instrument on the OSIRIS-REx asteroid sample return mission scheduled for launch in September 2016. The REXIS science mission is to characterize the elemental abundances of the asteroid Bennu on a global scale and to search for regions of enhanced elemental abundance. The thermal design of the REXIS instrument is challenging due to both the science requirements and the thermal environment in which it will operate. The REXIS instrument consists of two assemblies: the spectrometer and the solar X-ray monitor (SXM). The spectrometer houses a 2x2 array of back illuminated CCDs that are protected from the radiation environment by a one-time deployable cover and a collimator assembly with coded aperture mask. Cooling the CCDs during operation is the driving thermal design challenge on the spectrometer. The CCDs operate in the vicinity of the electronics box, but a 130 °C thermal gradient is required between the two components to cool the CCDs to -60 °C in order to reduce noise and obtain science data. This large thermal gradient is achieved passively through the use of a copper thermal strap, a large radiator facing deep space, and a two-stage thermal isolation layer between the electronics box and the DAM. The SXM is mechanically mounted to the sun-facing side of the spacecraft separately from the spectrometer and characterizes the highly variable solar X-ray spectrum to properly interpret the data from the asteroid. The driving thermal design challenge on the SXM is cooling the silicon drift detector (SDD) to below -30 °C when operating. A two-stage thermoelectric cooler (TEC) is located directly beneath the detector to provide active cooling, and spacecraft MLI blankets cover all of the SXM except the detector aperture to radiatively decouple the SXM from the flight thermal environment. This paper describes the REXIS thermal system requirements, thermal design, and analyses, with a focus on the driving thermal design challenges for the instrument. It is shown through both analysis and early testing that the REXIS instrument can perform successfully through all phases of its mission.

Stout, Kevin D.; Masterson, Rebecca A.

2014-08-01

433

Decoupling factors affecting plant diversity and cover on extensive green roofs.  

PubMed

Supplemental irrigation systems are often specified on green roofs to ensure plant cover and growth, both important components of green roof performance and aesthetics. Properties of the growing media environment too can alter the assemblage of plant species able to thrive. In this study we determine how plant cover, above ground biomass and species diversity are influenced by irrigation and growing media. Grass and forb vegetative cover and biomass were significantly greater in organic based growing media but there was no effect of supplemental irrigation, with two warm season grasses dominating in those treatments receiving no supplemental irrigation. On the other hand, plant diversity declined without irrigation in organic media, and having no irrigation in inorganic growing media resulted in almost a complete loss of cover. Sedum biomass was less in inorganic growing media treatments and species dominance shifted when growing media organic content increased. Our results demonstrate that supplemental irrigation is required to maintain plant diversity on an extensive green roof, but not necessarily plant cover or biomass. These results provide evidence that planting extensive green roofs with a mix of plant species can ensure the survival of some species; maintaining cover and biomass when supplemental irrigation is turned off to conserve water, or during extreme drought. PMID:24100190

MacIvor, J Scott; Margolis, Liat; Puncher, Curtis L; Carver Matthews, Benjamin J

2013-11-30

434

The effect of thermal gradients on the performance of lithium-ion batteries  

NASA Astrophysics Data System (ADS)

An experimental apparatus is described, in which Peltier elements are used for thermal control of lithium-ion cells under isothermal and non-isothermal conditions, i.e. to induce and maintain thermal gradients. Lithium-ion battery packs for automotive applications consist of hundreds of cells, and depending on the pack architecture, individual cells may experience non-uniform thermal boundary conditions. This paper presents the first study of the impact of artificially induced thermal gradients on cell performance. The charge transfer resistance of a 4.8 Ah is verified to have a strong temperature dependence following the Arrhenius law. Thermal cycling of the cell, combined with slow rate cyclic voltammetry, allows to rapidly identify phase transitions in electrodes, due to the thermal effect of entropy changes. A cell with a temperature gradient maintained across is found to have a lower impedance than one held at the theoretical average temperature. This feature is attributed to details of the inner structure of the cell, and to the non-linear temperature dependence of the charge transfer resistance.

Troxler, Yannic; Wu, Billy; Marinescu, Monica; Yufit, Vladimir; Patel, Yatish; Marquis, Andrew J.; Brandon, Nigel P.; Offer, Gregory J.

2014-02-01

435

Performance of a Thermally Stable Polyaromatic Hydrocarbon in a Simulated Concentrating Solar Power Loop  

SciTech Connect

Polyaromatic hydrocarbon thermal fluids showing thermally stability to 600 C have been tested for solar thermal-power applications. Although static thermal tests showed promising results for 1-phenylnaphthalene, loop testing at temperatures to 450 C indicated that the fluid isomerized and degraded at a slow rate. In a loop with a temperature high enough to drive the isomerization, the higher melting point byproducts tended to condense onto cooler surfaces. So, as experienced in loop operation, eventually the internal channels of cooler components in trough solar electric generating systems, such as the waste heat rejection exchanger, may become coated or clogged affecting loop performance. Thus, pure 1-phenylnaphthalene, without addition of stabilizers, does not appear to be a fluid that would have a sufficiently long lifetime (years to decades) to be used in a loop at the temperatures greater than 500 C. The performance of a concentrating solar loop using high temperature fluids was modeled based on the National Renewable Laboratory Solar Advisory Model. It was determined that a solar-to-electricity efficiency of up to 30% and a capacity factor of near 60% could be achieved using a high efficiency collector and 12 h thermal energy storage.

McFarlane, Joanna [ORNL] [ORNL; Bell, Jason R [ORNL] [ORNL; Felde, David K [ORNL] [ORNL; Joseph III, Robert Anthony [ORNL] [ORNL; Qualls, A L [ORNL] [ORNL; Weaver, Samuel P [ORNL] [ORNL

2014-01-01

436

Final Design and Experimental Validation of the Thermal Performance of the LHC Lattice Cryostats  

NASA Astrophysics Data System (ADS)

The recent commissioning and operation of the LHC String 2 have given a first experimental validation of the global thermal performance of the LHC lattice cryostat at nominal cryogenic conditions. The cryostat designed to minimize the heat inleak from ambient temperature, houses under vacuum and thermally protects the cold mass, which contains the LHC twin-aperture superconducting magnets operating at 1.9 K in superfluid helium. Mechanical components linking the cold mass to the vacuum vessel, such as support posts and insulation vacuum barriers are designed with efficient thermalisations for heat interception to minimise heat conduction. Heat inleak by radiation is reduced by employing multilayer insulation (MLI) wrapped around the cold mass and around an aluminium thermal shield cooled to about 60 K. Measurements of the total helium vaporization rate in String 2 gives, after substraction of supplementary heat loads and end effects, an estimate of the total thermal load to a standard LHC cell (107 m) including two Short Straight Sections and six dipole cryomagnets. Temperature sensors installed at critical locations provide a temperature mapping which allows validation of the calculated and estimated thermal performance of the cryostat components, including efficiency of the heat interceptions.

Bourcey, N.; Capatina, O.; Parma, V.; Poncet, A.; Rohmig, P.; Serio, L.; Skoczen, B.; Tock, J.-P.; Williams, L. R.

2004-06-01

437

Additive Manufacturing Thermal Performance Testing of Single Channel GRCop-84 SLM Components  

NASA Technical Reports Server (NTRS)

The surface finish found on components manufactured by sinter laser manufacturing (SLM) is rougher (0.013 - 0.0006 inches) than parts made using traditional fabrication methods. Internal features and passages built into SLM components do not readily allow for roughness reduction processes. Alternatively, engineering literature suggests that the roughness of a surface can enhance thermal performance within a pressure drop regime. To further investigate the thermal performance of SLM fabricated pieces, several GRCop-84 SLM single channel components were tested using a thermal conduction rig at MSFC. A 20 kW power source running at 25% duty cycle and 25% power level applied heat to each component while varying water flow rates between 2.1 - 6.2 gallons/min (GPM) at a supply pressure of 550 to 700 psi. Each test was allowed to reach quasi-steady state conditions where pressure, temperature, and thermal imaging data were recorded. Presented in this work are the heat transfer responses compared to a traditional machined OHFC Copper test section. An analytical thermal model was constructed to anchor theoretical models with the empirical data.

Garcia, Chance P.; Cross, Matthew

2014-01-01

438

Rooftop Membrane Temperature Reductions with Green Roof Technology in South-Central Texas  

E-print Network

Early green roof cooling and energy reduction research in North America took place in Canada and the northern latitudes of the United States, where green roofs reduced rooftop temperatures by 70% to 90%. Less is known about green roof technology...

Dvorak, B.

439

40 CFR 443.30 - Applicability; description of the asphalt roofing subcategory.  

Code of Federal Regulations, 2010 CFR

... false Applicability; description of the asphalt roofing subcategory. 443.30 Section 443...FOR THE PAVING AND ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Roofing Subcategory § 443.30...

2010-07-01

440

40 CFR 443.30 - Applicability; description of the asphalt roofing subcategory.  

Code of Federal Regulations, 2014 CFR

... false Applicability; description of the asphalt roofing subcategory. 443.30 Section 443...FOR THE PAVING AND ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Roofing Subcategory § 443.30...

2014-07-01

441

40 CFR 443.30 - Applicability; description of the asphalt roofing subcategory.  

Code of Federal Regulations, 2012 CFR

... false Applicability; description of the asphalt roofing subcategory. 443.30 Section 443...FOR THE PAVING AND ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Roofing Subcategory § 443.30...

2012-07-01

442

40 CFR 443.30 - Applicability; description of the asphalt roofing subcategory.  

Code of Federal Regulations, 2011 CFR

... false Applicability; description of the asphalt roofing subcategory. 443.30 Section 443...FOR THE PAVING AND ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Roofing Subcategory § 443.30...

2011-07-01

443

40 CFR 443.30 - Applicability; description of the asphalt roofing subcategory.  

Code of Federal Regulations, 2013 CFR

... false Applicability; description of the asphalt roofing subcategory. 443.30 Section 443...FOR THE PAVING AND ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Roofing Subcategory § 443.30...

2013-07-01

444

Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)  

SciTech Connect

This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'speciali