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1

Thermal Performance Evaluation of Innovative Metal Building Roof Assemblies  

SciTech Connect

In order to meet the coming energy codes, multiple layers of various insulation types will be required. The demand for greater efficiency has pushed insulation levels beyond the cavity depth. These experiments show the potential for improving metal building roof thermal performance. Additional work is currently being done by several stakeholders, so the data is expanding. These experiments are for research and development purposes, and may not be viable for immediate use.

Walker, Daniel James [ORNL; Zaltash, Abdolreza [ORNL; Atchley, Jerald Allen [ORNL

2011-01-01

2

Thermal performance of insulated metal building roof deck constructions  

Microsoft Academic Search

System thermal resistance (R) values were measured in full-scale guarded hot box tests, in accordance with ASTM Test for Thermal Conductance and Transmittance of Built-Up Sections by Means of the Guarded Hot Box (C 236), on a series of ten insulated metal building roof deck constructions. Orientation of the hot box was horizontal, with heat flow upward for the test

R. G. Miller; M. Sherman

1983-01-01

3

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

4

Numerical evaluation of the thermal performances of roof-mounted radiant barriers  

E-print Network

This paper deals with the thermal performances of roof-mounted radiant barriers. Using dynamic simulations of a mathematical model of a whole test cell including a radiant barrier installed between the roof top and the ceiling, the thermal performance of the roof is calculated. The mean method is more particularly used to assess the thermal resistance of the building component and lead to a value which is compared to the one obtained for a mass insulation product such as polyurethane foam. On a further stage, the thermal mathematical model is replaced by a thermo-aeraulic model which is used to evaluate the thermal resistance of the roof as a function of the airflow rate. The results shows a better performance of the roof in this new configuration, which is widely used in practice. Finally, the mathematical relation between the thermal resistance and the airflow rate is proposed.

Miranville, Frédéric; Lucas, Franck; Johan, Seriacaroupin

2014-01-01

5

Experimental evaluation of thermal and energy performance of temperate green roofs: a case study in Beijing  

NASA Astrophysics Data System (ADS)

An experimental evaluation of thermal and energy performance of temperate green roofs was carried out by thermal and meteorological observation and energy budget modeling using a setup of green roof in Beijing urban area. From both the yearly and daily temperature trends, the green roof could effectively damp down the undulation of roof surface temperature comparing with the conventional one. As an insulating screen, the green roof abated the amplitude of temperature by 9.0 in winter and 9.1 °C in summer, respectively. Under different cloud conditions, the green roof in summer time resulted in decreases in sensible heat and heat flux by 125.3W m-2 and 32.0 W m-2, respectively, on daily average comparing with the conventional one. Based on the energy budget analyses, under an assumptive scenario of 50% roof-greening in Beijing, a total of 34.1 PJ of sensible heat and 8.7 PJ of heat flux would be decreased for a summer period of 90 days. This study demonstrated that green roof, serving as an insulating screen to building top in comparison with the conventional roof, proved thermal improving effect in building scale and high energy saving potential for urban development.

Sun, T.; Institute of Hydrology; Water Resources

2011-12-01

6

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

NASA Astrophysics Data System (ADS)

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

Mukherjee, Sananda

7

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

E-print Network

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

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

2004-01-01

8

Role of Roof Treatment in Thermal Design of Buildings  

Microsoft Academic Search

The paper describes the treatment of roof sections used by the construction agencies in different parts of India for low income group and economically weaker sections of the society. The thermal performance of roofs should be improved for alleviating indoor thermal conditions and minimizing the effect of solar heat in buildings. The evaluation of various roof sections reveals that the

B. M. Suman; B. K. Saxena

1992-01-01

9

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

E-print Network

climatic condition of very hot and dry region in Egypt (Toshky region). The external climatic conditions and the temperature distribution inside the roof construction and the indoor air temperature were measured. The results of this study recognized...

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

2010-01-01

10

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

E-print Network

. These include storm- water retention, energy conservation, reduction in the urban heat island effect, increased in the urban heat island effect, increased longevity of the roofing membrane, the ability of plants to create-Battelle, LLC, under Contract No. DE-AC05- 00OR22725 with the U.S. Department of Energy. The United States

Oak Ridge National Laboratory

11

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

Microsoft Academic Search

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

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

2005-01-01

12

Energy Performance Aspects of a Florida Green Roof  

E-print Network

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... heat flux estimates show the green roof to have an average heat flux of 0.39 Btu/ft 2 /hr or 18.3% less than the conventional roof’s average heat flux rate of 0.48 Btu/ft 2 /hr. Winter data again show significantly lower peak roof surface...

Sonne, J.

2006-01-01

13

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

14

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

15

Thermal behavior of curved roof buildings exposed to solar radiation and wind flow for various orientations  

Microsoft Academic Search

In this study air flow, solar radiation and heat transfer from a two dimensional curved roof with north-south and east-west faced are determined and results are compared with flat roof for the same size and orientation. Comparison are performed for their corresponding roof surface temperature, and heat flow for several roof rim angles and also for various wind flow velocities,

M. Hadavand; M. Yaghoubi

2008-01-01

16

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

E-print Network

into the conditioned space. The attic floor consists of a metal deck, a 1-in.-thick piece of wood fiberboard Table 1. Stone-coated metal shakes field tested on the steep-slope attic assembly Profile Color Pigment Surface Underside Attachment Above- sheathing... Figure 3). Figure 3. Roof deck construction with battens and counter-battens. Figure 4. South-facing steep-slope attic assemblies placed atop the roof testing facility. lying on the metal deck, and a ½-in.-thick piece of wood fiberboard...

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

2006-01-01

17

Energy Performance Aspects of a Florida Green Roof Part 2  

E-print Network

temperatures for the green roof compared with the conventional roof and a significant shift in when the peak green roof temperature occurs compared to the conventional roof. Data analysis of the same 2005 period also shows lower heat fluxes for the green roof...

Sonne, J.; Parker, D.

18

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

19

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

20

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

E-print Network

Hamerschlag Hall Green Roof Storm Water Retention and Runoff Reduction Performance performance in reducing storm water runoff and extending the runoff duration. Green roofs can reduce the amount and rate of storm water runoff by covering the impervious roof with porous soils that can retain

Andrews, Peter B.

21

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

22

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

Microsoft Academic Search

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

Colleen Butler; Colin M. Orians

2011-01-01

23

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

SciTech Connect

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

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

1980-06-01

24

ManualforEvaluatingtheThermalPerformanceofthe HamerschlagHallGreenRoof  

E-print Network

Buck of Civil and Environmental Consultants. They also thank Ms. Darla Cravotta, special projects for their assistance with various aspects of the project. #12;iii TableofContents 1 Abstract maintenance costs. Reduced heating and cooling costs ­ Provides extra roof insulation. And reduction

Andrews, Peter B.

25

Hygrothermal Performance of Protected Membrane Roof Systems: Part 2: Experimental Verification  

Microsoft Academic Search

In a previous paper by the same author [1], a simplified analysis of the heat and moisture response of protected membrane roofs (PMR) was discussed. The analysis included a ?U-correction to the thermal transmission coefficient U of the equivalent, conventional roof to account for the effects of percolation, evapora tion, and butt joint losses between the insulation boards. This second

H. Hens

1996-01-01

26

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

27

Field measurements of performance of roof solar collector  

Microsoft Academic Search

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

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

2000-01-01

28

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

29

A 40KW ROOF MOUNTED PV THERMAL CONCENTRATOR SYSTEM J.F.H. Smeltink1  

E-print Network

technology since 1995. The latest development for ANU- CSES is a photovoltaic thermal (PV-T) technology) collector technology. This paper describes a roof mounted 40 kW PV-T concentrator system which was installed near market ready renewable energy technologies. In partnership with Rheem/Solahart, ANU- CSES accessed

30

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

E-print Network

costs. METHODS In order to test our hypothesis, we need to get feedback from real buildings on the performance of their vegetative roofs, and the costs involved in these roofs. Questionnaire as a Data Collecting Tool There are different... that aims at getting feedback from real-life projects which are subject to all sorts of physical conditions, and with which people interact. Taking into consideration the above-mentioned points, it has been concluded that the use of a questionnaire...

Anderson, J.; Azarbayjani, M.

31

DYNAMIC THERMALLY-DISCONNECTED BUILDING ENVELOPES A NEW PARADIGM FOR WALLS AND ROOFS IN LOW ENERGY BUILDINGS  

Microsoft Academic Search

This paper describes numerical and experimental analysis of a novel design concept. Traditionally the thermal design of building envelope assemblies is based on a static energy flow. However, building envelopes are subject to varying environmental conditions. This mismatch between the steady-state principles used in the design of roofs and walls and their dynamic operation results in relatively low thermal efficiency.

William A Miller; Jan Kosny; Abdolreza Zaltash

2010-01-01

32

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

33

Effect of roof solar reflectance on the building heat gain in a hot climate  

Microsoft Academic Search

The effect of the roof solar reflectance on the thermal performance of a building is often ignored. However, there are significant differences in heat gain from light and dark-coloured roof surfaces. In this paper an equation for the average daily downward heat flow of a sunlit roof is derived. Using building simulation, it is first shown that the thermal mass

Harry Suehrcke; Eric L. Peterson; Neville Selby

2008-01-01

34

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

Microsoft Academic Search

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

1993-01-01

35

THERMAL ?-? MODULATOR: PERFORMANCE ANALYSIS  

Microsoft Academic Search

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

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

36

A naturally ventilated cavity roof as potential benefits for improving thermal environment and cooling load of a factory building  

Microsoft Academic Search

The impact of natural ventilation of a roof cavity on improvement of the thermal environment and reduction of cooling load of a factory building is discussed. A computer program was developed with the logic in a companion paper [1] to observe the effect of cavity ventilation on the operative temperature of the occupied zone in the factory. Comparisons were made

L. Susanti; H. Homma; H. Matsumoto

2011-01-01

37

Performance of oil palm EFB fibre reinforced concrete roof slates  

Microsoft Academic Search

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

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

2010-01-01

38

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

NASA Astrophysics Data System (ADS)

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

Resmini, Ronald G.

2008-04-01

39

Roof System EPDM Shrinkage.  

ERIC Educational Resources Information Center

Looks at Ethylene Propylene Diene Terpolymer rubber roof membranes and the potential problems associated with this material's shrinkage. Discusses how long such a roof should perform and issues affecting repair or replacement. Recommends that a building's function be considered in any roofing decision. (RJM)

Betker, Edward

1998-01-01

40

Users installing systems below metal roofs  

Microsoft Academic Search

Fiberglass insulation can be installed below metal roofs for 62% less per R-value than traditional installation and material costs of insulating above the roof. Installation above the roof only makes sense if roof repairs are needed or if the roof needs replacing. Critics claim the subsystems form a thermal short by crushing the insulation against metal sheeting and allowing heat

Stokes

1984-01-01

41

Experimental polyurethane foam roof systems, part 2  

NASA Astrophysics Data System (ADS)

An experimental roofing installation is described in which polyurethane foam (PUF) was spray-applied directly to metal Butlerib-type metal decks, the roof divided into five approximately equal areas, and the PUF protected with five different elastomeric coating systems. Three of the coating systems were damaged by hailstones about a year after installation; these systems were recoated within 3 years of the initial installation. The current coatings include two of the original coating systems - a plural component silicone and a single component silicone - and those applied over the three systems damaged by hail - a single component silicone, an aluminum filled, hydrocarbon-extended catalyzed urethane, and a catalyzed urethane. The performance of these five PUF systems over a 7-year period is reported. The temperature distributions throughout the roof systems are described. The decay in the thermal conductivity of the PUF roof over a 5-year period is presented, and the energy savings realized by foaming the roof are presented.

Alumbaugh, R. L.; Keeton, J. R.; Humm, E. F.

1983-01-01

42

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

43

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...

44

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

Microsoft Academic Search

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

David Infield; Mark Harding

45

A Measurement Method of Actual Thermal Performance of Detached Houses  

E-print Network

of the thermal performance of the envelope surfa as walls, roofs and windows, on the energy used by HVAC system is not so large in normal office buildings. Inthe detached houses, however, it is not too small to be neglected because of the relatively largeness... of the wall surface to the volume of the room space. If the house does not have the proper thermal performance, it is very difficult to etermine which the main reason is, the malfunction of the heating equipment or bad thermal performance of the envelope...

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

2004-01-01

46

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

47

Roof angle for optimum thermal and energy performance of insulated roof  

Microsoft Academic Search

Mineral wool is among the commonly used conductive insulation material for building insulation. Studies on insulated building envelope in temperate climate have shown potential energy savings towards attaining energy efficient buildings and sustainable built environment. To date, there is no empirical data on the benefits of insulated building envelope in warm humid tropical climate. Such data would provide commercial mileage

S. Syiful Irwan; A. Zain Ahmed; N. Ibrahim; N. Z. Zakaria

2009-01-01

48

IMPROVED ROOF STABILIZATION TECHNOLOGIES  

SciTech Connect

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

M.A. Ebadian, Ph.D.

1999-01-01

49

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

SciTech Connect

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

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

1996-03-01

50

Roof Roundup.  

ERIC Educational Resources Information Center

The roof management program at the University of Wyoming involved a consulting firm that provided a computer analysis of the condition of each roof on campus and trained university personnel to act as inspectors in the future. (MLF)

American School and University, 1984

1984-01-01

51

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

Microsoft Academic Search

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

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

2011-01-01

52

Roofing: Workbook and Tests. Built-up Roofing.  

ERIC Educational Resources Information Center

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

Klingensmith, Robert, Ed.

53

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, âÂÂâ¦as well as protective strategies, energy and air filtration issues, roofing materials, and gutters and downspouts.â Throughout the document, users can rely on drawings and photographs that illustrate various rehabbing techniques. Much is revealed here, including timely information on low-slope and metal roofing, along with suggestions on installing moisture barriers.

1999-01-01

54

PERFORMANCE OF LOCALLY PRODUCED COLD-FORMED STEEL SECTIONS FOR ROOF TRUSS SYSTEM  

Microsoft Academic Search

Traditionally, timber is usually used for roof truss as a construction material. However, the use of timber is no longer popular recently due to the increase in cost, not environmental- friendly as more trees need to be cut, prone to termite attack, and lesser capacity compared with steel. Cold-formed steel section has been introduced in this paper for the construction

MAHMOOD M. T

55

LSST mirror thermal performance  

NASA Astrophysics Data System (ADS)

The proposed science missions of the LSST require a telescope with an optical etendue of greater than 250 meters square degrees square. The current LSST Baseline Configuration has a field of view of 3.5 degrees and an optical etendue of 302 m2d2. The etendue calculation includes the effect of gradual vignetting by the camera as the field angle increases. A current optical point design includes spun cast light-weighted borosilicate mirrors (primary and tertiary) of 8.4 and 5 m diameter respectively. Thermal control systems are needed to optimize telescope seeing and to minimize the thermal distortion of the mirrors. The goals of this study are to determine the airflow requirements for the specified ambient temperature rate of change, to identify thermal time constants and to predict the magnitude and form of thermal distortions that can be developed by environmental conditions. Operational data taken at the 6.5 m MMT (Multi-Mirror Telescope Observatory) and at the Magellan Observatory are presented for comparison with this study. Finally, the results from the thermal analysis were used to simulate the LSST focus control over one night of observation and to estimate the effect on the image quality for different correction frequencies.

Cuerden, Brian; Sebag, Jacques; West, Steve

2004-09-01

56

Improved roof stabilization technologies  

SciTech Connect

Decontamination and decommissioning (D and D) activities require that personnel have access to all areas of structures, some of which are more than 40 years old. In many cases, these structures have remained in a standby condition for up to 10 years; few preventative maintenance activities have been performed on them because of lack of funding or a defined future plan of action. This situation has led to deteriorated building conditions, resulting in potential personnel safety hazards. In addition, leaky roofs allow water to enter the buildings, which can cause the spread of contamination and increase building deterioration, worsening the already unsafe working conditions. To ensure worker safety and facilitate building dismantlement, the assessment of roof stabilization techniques applicable to US Department of Energy (DOE) structures has become an important issue. During Fiscal year 1997 (FY97), a comprehensive reliability-based model for the structural stabilization analysis of roof system in complex structures was developed. The model consists of three major components: a material testing method, a deterministic structural computer model, and a reliability-based optimization, and probabilistic analyses of roof structures can be implemented. Given site-specific needs, this model recommends the most appropriate roof stabilization system. This model will give not only an accurate evaluation of the existing roof system in complex structures, but it will also be a reliable method to aid the decision-making process. This final report includes in its appendix a Users` Manual for the Program of Deterministic and Reliability Analysis of Roof Structures.

Ebadian, M.A.

1998-01-01

57

Roofing panels  

SciTech Connect

A roofing panel of glass-reinforced plastic (G.R.P.) or sheet metal is stiffened by longitudinal beams on its underside to span one pitch of a pitched roof from eaves to ridge. It has an outer skin and an inner impervious liner spaced therefrom and supported on the stiffening beams so as to form a tunnel open at both ends and extending from the vicinity of the eaves to theline of the roof ridge, where vents to atmosphere are provided in the outer skin. Air is convected upwards through the tunnel due to the heating of the outer skin by radiation from the sun. At the eaves end the tunnel also has an inlet port communicating with the roof space, and a damper controls the air flowing in from outside the building and the air flowing in from the roof space. At the line of the ridge the liner meets and is sealed on the corresponding liner of a counterpart panel on the opposite pitch of the roof so as to maintain the integrity of the convection air circuit in each section of the roof. A heat exchanger located in the tunnel transfers heat from the convected air to a hot water system in the building. A hollow box girder spans the width of the panel across the beams so as to rest on the top of a flank wall of the building and can be filled with concrete to anchor the panel in position.

Brill-edwards, K.O.

1983-05-10

58

Roofing panels  

Microsoft Academic Search

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

Brill-edwards

1983-01-01

59

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

60

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

61

Thermal ?-? Modulator: Anemometer Performance Analysis  

Microsoft Academic Search

In this paper we propose a feedback architecture with a thermosensitive sensor, based on the thermal ?-? principle to realize digital measurement of physical quantities that interacts with the sensor: temperature, thermal radiation, fluid speed. This architecture uses a 1-bit ?-? modulator for which a considerable part of the conversion functions is performed by a thermosensitive sensor. The sensor is

Will R. M. Almeida; Georgina M. Freitas; Lígia S. Palma; Sebastian Y. C. Catunda; Raimundo C. S. Freire; Francisco F. Santos; Amauri Oliveira; Hassan Aboushady

2007-01-01

62

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

63

INSTALLATION CERTIFICATE CF-6R-ENV-01 Envelope Insulation; Roofing; Fenestration (Page 1 of 3)  

E-print Network

: The roof area covered by building integrated photovoltaic panels and building integrated solar thermal panels are exempt from the above Cool Roof criteria. Roof constructions that have thermal mass over

64

Performance of thermal envelope houses  

Microsoft Academic Search

The performance of a hypothetical thermal envelope house is evaluated based on the results of a year-long thermal network simulation. The house has a floor area of 1500 ft² (139 m²) and 360 ft² (33.5 m²) south-facing double glazing, half vertical and half at a 45° tilt. The above grade inner and outer envelope walls have nominal resistances of R-11

J. Kohler; D. Lewis

1980-01-01

65

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

66

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

Microsoft Academic Search

Thermal Infrared Multispectral Scanner (TIMS) data are processed to yield surface temperatures over the lava tube system of Kilauea Volcano, Hawaii. TIMS is a 6-band airborne longwave infrared (8 mum to 12 mum) multispectral imaging system built and operated by the National Aeronautics and Space Administration (NASA). The data analyzed were collected in 1988 and are part of the Compiled

Ronald G. Resmini

2008-01-01

67

Keys to a Successful Roofing System.  

ERIC Educational Resources Information Center

Provides advice on successfully managing an educational facility's roofing system by first getting the best roofing system possible, then undertaking regular precautionary measures to assure its peak performance. Specific points address such areas as choosing a roofing contractor, hiring a professional to create specifications, monitoring…

Kornahrens, Rob

1999-01-01

68

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

69

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

SciTech Connect

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

Syd S. Peng

2005-10-01

70

Green roofs: potential at LANL  

SciTech Connect

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

Pacheco, Elena M [Los Alamos National Laboratory

2009-01-01

71

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

Microsoft Academic Search

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

Joseph Khedari

72

Roofing Systems Have Continued To Improve in Quality.  

ERIC Educational Resources Information Center

Discusses the benefits of each of three types of roofing systems: built-up roofing (BUR); modified bitumen; and a combination of BUR and modified bitumen. Roof performance, performance maximization, and inspection and maintenance issues are addressed. A brief glossary of commercial roofing terms is included. (GR)

Hobson, Joseph W.

2000-01-01

73

Rules To Roof By.  

ERIC Educational Resources Information Center

Advises schools on keeping roofs healthy, thereby saving costly repairs to both the roof and the entire building. Discusses inspections, preventive-maintenance programs, weather, and when to re-roof. (EV)

Hale, Olivia

2002-01-01

74

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

75

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

SciTech Connect

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

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

1998-01-01

76

Introduction, Energy savings of reflective roofs  

SciTech Connect

Several experiments on individual buildings in California and Florida show that reflective (cool) roofs reduce air-conditioning energy use between 10 percent and 50 percent. The savings, of course, are strong functions of the thermal integrity of building and climate conditions. Darker roofs more quickly warm the air over urban areas, leading to the creation of summer urban ''heat islands.'' On the community scale, increasing the albedo (solar reflectivity) of roofs can limit or reverse an urban heat island effectively and inexpensively. This publication discusses the literature data and new research efforts in analyzing the impact of cool roofs on buildings' cooling and heating energy use.

Akbari, H.

1998-01-15

77

Introduction, Energy savings of reflective roofs  

Microsoft Academic Search

Several experiments on individual buildings in California and Florida show that reflective (cool) roofs reduce air-conditioning energy use between 10 percent and 50 percent. The savings, of course, are strong functions of the thermal integrity of building and climate conditions. Darker roofs more quickly warm the air over urban areas, leading to the creation of summer urban ''heat islands.'' On

Akbari

1998-01-01

78

Analytical study of residential building with reflecting roofs  

Microsoft Academic Search

This report presents an analysis of the effect of roof solar reflectance on the annual heating (cooling) loads, peak heating (cooling) loads, and roof temperatures of the residential buildings. The annual heating (cooling) loads, peak heating (cooling) loads, and exterior roof temperatures for a small compact ranch house are computed using the Thermal Analysis Research Program (TARP). The residential models,

Zarr

1998-01-01

79

what is a cool roof? what is the  

E-print Network

on hot, sunny days. Solar reflectance refers to a material's ability to reflect the sun's solar energy The Cool Roof Rating Council (CRRC), at www.coolroofs.org, is the sole entity the California Energy the value, the `cooler' the roof. Solar Re ectance: the ability of a roof to re ect solar energy Thermal

80

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

E-print Network

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

81

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

82

Impact of Sustainable Cool Roof Technology on Building Energy Consumption  

NASA Astrophysics Data System (ADS)

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

Vuppuluri, Prem Kiran

83

Summer Roof Maintenance.  

ERIC Educational Resources Information Center

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

Liscum, Curtis L.

1999-01-01

84

Validation of a computer simulation of the cooling and heating performance of a roof pond building based upon a detailed analysis of measured heat transfer  

Microsoft Academic Search

Roof pond system heating and cooling data acquired at Trinity University's Passive Test Facility for warm, humid climates has been analyzed. This analysis has produced a set of validated algorithms which can be used to calculate: the heat dissipation from a dry surface roof pond, the heat dissipation from a flooded roof pond, heat loss or gain through the insulated

F. Loxsom; E. E. Clark; J. Faultersack; B. S. Schutt; L. Hoffstatter; E. S. Doderer

1985-01-01

85

Natural selection on thermal performance in a novel thermal environment.  

PubMed

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

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

2014-09-30

86

Urban solarium : thermal performance in Boston  

E-print Network

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

Hsu, Juliet Chia-Wen

2012-01-01

87

Evolution of cool-roof standards in the United States  

SciTech Connect

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

Akbari, Hashem; Akbari, Hashem; Levinson, Ronnen

2008-07-11

88

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

89

What's Up with Your Roof?  

ERIC Educational Resources Information Center

Explains the importance of knowing what condition the school's roof(s) is in and how to design a preventive maintenance program that is cost effective and will help extend the roof's lifecycle. Cost calculation techniques to value a roof maintenance program, maintenance documentation requirements, and roof surveying are discussed. (GR)

Kalinger, Peter

1998-01-01

90

Thermal control surfaces experiment flight system performance  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

91

Thermal performance of double-skin facade with thermal mass  

NASA Astrophysics Data System (ADS)

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

Fallahi, Ali

92

NISTIR 7401 Thermal Performance of Fire Resistive Materials  

E-print Network

to Thermal Performance Models Dale P. Bentz Kuldeep R. Prasad #12;NISTIR 7401 Thermal Performance of Fire Resistive Materials I. Characterization with Respect to Thermal Performance Models Dale P. Bentz Kuldeep R

Bentz, Dale P.

93

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

Microsoft Academic Search

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

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

2009-01-01

94

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

95

Thermal control surfaces experiment flight system performance  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

96

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

97

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

98

Polyurethane-based organic aerogels' thermal performance  

Microsoft Academic Search

A novel type of chemistry based on the use of polyisocyanates which can be turned into heavily cross-linked polyurethanes (PUR), polyureas, polyurethone imines or polyisocyanurates (PIR) to make organic aerogels is now being developed. Feasibility study of the polyisocyanate-based aerogels and various parameter effects on the thermal performance of these materials are described. This paper focuses on the low density

G. Biesmans; D. Randall; E. Francais; M. Perrut

1998-01-01

99

Thermal design and performance of HAMSAT  

NASA Astrophysics Data System (ADS)

HAMSAT is a micro-satellite for providing satellite-based Amateur Radio services to the national as well as the international community of Amateur Radio Operators (HAMs). Micro-satellites (less than 100 kg) are becoming increasingly utilized as an economical means of experimentation and research in orbit. The thermal control of micro-satellite presents unique challenges to the thermal engineer since the mass; power and volume available are all very limited. Regardless of these problems and the extreme environments and changing power conditions (internally and externally) of the satellites the subsystems must still be maintained within the specified temperature limits. HAMSAT spins about an axis perpendicular to orbital plane and is placed in 632×621km altitude sun-synchronous orbit. The three new technologies experimented in the spacecraft are lithium-ion batteries, Bus Management Unit and multi junction gallium arsenide solar cells in LEO orbit. A purely passive thermal control system without heaters is used to control the temperature of the spacecraft. Thermal design and on-orbit temperature characteristics are presented and discussed. The spacecraft has completed one year of operation on orbit. The on orbit thermal performance of the spacecraft is good and matches well with the prediction. Impact of variation in thermal parameters on temperature is discussed.

Badari Narayana, K.; Venkata Reddy, V.

2007-01-01

100

Roofing Workbook and Tests: Rigid Roofing.  

ERIC Educational Resources Information Center

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

Klingensmith, Robert, Ed.

101

Thermal performance of insulated pipe systems  

SciTech Connect

The thermal performance of insulated pipe systems was measured as a function of insulation and pipe system parameters. Insulation parameters included insulation material, thickness, and air gaps at seams and joints. Pipe system parameters were pipe size, hangers, supports, and operating temperature. Over 150 thermal performance tests were recorded and analyzed over a two-year period. Test results show a 15 percent deterioration in thermal performance for a 305-mm (1-ft) insulated pipe section with a 6.4-mm (0.25-in.) butt-joint air gap. The method of insulating pipe hangers and supports is a major component of pipe system heat analysis. Glass fiber and calcium silicate pipe insulations were tested with a variety of hanger and support configurations. The magnitude of heat loss was recorded as a function of several parameters including the degree of hanger/support insulation. A 305-mm (1-ft) glass fiber pipe insulation section containing a hanger had an additional 14 to 40 percent heat loss, depending on the hanger insulation, compared to that of an uninterrupted insulated pipe section. Results from the data analysis and ASTM Practice for Determination of Heat Gain or Loss and Surface Temperature of Insulated Pipe and Equipment Systems by the Use of a Computer Program (C 680) were combined to form computer program HEATLOSS. The good correlation between the thermal performance predicted by HEATLOSS and the actual test data indicates that HEATLOSS can be used to estimate thermal performance effects from variations in insulating material and pipe system design.

Sullivan, J.M.

1981-12-01

102

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

103

Green Roofs for Stormwater Management  

EPA Science Inventory

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

104

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

105

Roof Coatings Manufacturers Association  

NSDL National Science Digital Library

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

2006-11-21

106

Design of a hybrid composite roof bar  

SciTech Connect

This project entailed the design and construction of a hybrid composite roof bar for a passenger vehicle in accordance to AS 1235-1989. The design was based on finite element modeling. The manufacture of the roof bar incorporated tool fabrication and a wet lay-up technique. Experimental substantiation of the roof bar was performed by testing the roof bar to the static loading requirements set by AS 1235-1989. The findings of both the finite element and experimental work were presented and discussed, which included a comparison between the two sets of results. A commercial manufacture technique which could be adopted, alternative designs, and the applicability of composites in high load bearing automotive structures, were also discussed and recommended.

Falzon, P.J.; Janardhana, M.N. [Royal Melbourne Institute of Technology (Australia). Dept. of Aerospace Engineering

1993-12-31

107

Thermal performance of cold storage in thermal battery for air conditioning  

Microsoft Academic Search

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

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

2004-01-01

108

Shuttle TPS thermal performance and analysis methodology  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

109

Proceedings of the roof wind uplift testing workshop  

SciTech Connect

On November 8--9, 1989, a group of concerned roofing professionals gathered in Oak Ridge, Tennessee, to exchange information and to hear discussions on topics dealing with wind's effect on roofs. Several important issues were addressed: (1) Wind-related roofing problems are a concern to the roofing industry; (2) There is no comprehensive understanding in the US roofing industry of the dynamics of wind phenomena; (3) There is inadequate field data on wind's effect of roof performance; (4) The correlation between field performance and laboratory testing is poor; (5) Procedures for laboratory testing and field testing are inadequate for many roof systems; (6) There is little roof uplift resistance research underway in the US, and what does exist is poorly coordinated; (7) Manuals, test procedures, standards, and codes for wind uplift are often inadequate, even confusion and contradictory at times; and (8) Building owners are not well enough informed to commit to the cost of wind uplift technology development or even to the design and construction of stronger roofs. These concerns led one group, the Single Ply Roofing Institute (SPRI), to commission a study in 1986 to determine the feasibility of an apparatus for testing whole roof assemblies under conditions that closely simulated real roof wind effects. Results from this study were shared with Oak Ridge National Laboratory (ORNL) which has subsequently submitted a review. A major conclusion from the joint talks with ORNL was the importance of avoiding decisions on an individual uplift testing concept with too narrow a focus on wind-related roofing issues. Subsequently, it was decided to schedule a workshop on the topic with the original sponsors being SPRI, ORNL, and the Naval Civil Engineering Laboratories (NCEL). Each document will have a separate abstract.

Courville, G.E. (comp.); Gillis, P.S. (ed.)

1990-02-01

110

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

111

Computing Thermal Performances Of Shafts And Bearings  

NASA Technical Reports Server (NTRS)

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

Woods, Claudia M.

1992-01-01

112

The Influence of Ambient Temperature on Green Roof R-values  

NASA Astrophysics Data System (ADS)

Green roofs can be an effective and appealing way to increase the energy efficiency of buildings by providing active insulation. As plants in the green roof transpire, there is a reduction in heat flux that is conducted through the green roof. The R-value, or thermal resistance, of a green roof is an effective measurement of thermal performance because it can be easily included in building energy calculations applicable to many different buildings and situations. The purpose of this study was to determine if an increase in ambient temperature would cause an increase in the R-value of green roofs. Test trays containing green roof materials were tested in a low speed wind tunnel equipped to determine the R-value of the trays. Three different plant species were tested in this study, ryegrass (Lolium perenne), sedum (Sedum hispanicum), and vinca (Vinca minor ). For each test in this study the relative humidity was maintained at 45% and the soil was saturated with water. The trays were tested at four different ambient temperatures, ranging from room temperature to 120ºF. The resulting R-values for sedum ranged from 1.37 to 3.28 ft2hºF/BTU, for ryegrass the R-values ranged from 2.15 to 3.62 ft2hºF/BTU, and for vinca the R-values ranged from 3.15 to 5.19 ft2hºF/BTU. The average R-value for all the tests in this study was 3.20 ft2hºF/BTU. The results showed an increase in R-value with increasing temperature. Applying an ANOVA analysis to the data, the relationship between temperature and R-value for all three plant species was found to be statistically significant.

Cox, Bryce Kevin

113

Fourier analysis of conductive heat transfer for glazed roofing materials  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

114

Rod shop, roof and truss detail showing older pink roof ...  

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

Rod shop, roof and truss detail showing older pink roof truss, newer pratt truss, and longitudinal, truss for overhead traveling crane - Chicago, Burlington & Quincy Railroad, Roundhouse & Shops, Broadway & Spring Streets, Aurora, Kane County, IL

115

Using Green Roofs to Minimize Roof Runoff Pollution  

E-print Network

10/31/2008 1 Using Green Roofs to Minimize Roof Runoff Pollution Brett LongBrett Long Shirley ClarkTested membranes highly recommended ­­ Plastic root barrier above membrane?Plastic root barrier above membrane

Clark, Shirley E.

116

Performance potential of advanced solar thermal propulsion  

SciTech Connect

Design features, component test results, and performance levels of a solar thermal propulsion system for transferring payloads from LEO to GEO are detailed. Solar radiation is collected by two inflated paraboloidal reflectors which funnel the light into a radiant cavity through which propellant is flowing. The propellant, preferably H2 due to its high specific impulse at low temperatures, is then directed through a nozzle to provide 200 lb of thrust. Attention has been given to turbine, rotating bed, and seeded absorber configurations. Testing concentrated on directly heated concepts because of a potential 20 pct increase in thrust using 24.7 kWt concentrated on a 6 cm diameter spot. An open-ended-absorber reached a 76.9 pct thermal efficiency and delivered a specific impulse of 808 lbft-sec/lbm. Rhenium tubes were used in the final test design, which included a quartz window with an IR protective coating. Further component testing is recommended, together with investigations of advanced concepts, in order to assay the ultimate performance capabilities of the propulsion system.

Shoji, J.M.

1983-01-01

117

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

118

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

...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

119

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

120

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...

121

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...

122

High Performance Thermal Interface Technology Overview  

E-print Network

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

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

2008-01-07

123

Mine roof collapse  

Microsoft Academic Search

On the after noon of July 2, 1948, while returning from geological work, I took a short cut along the trail pictured across the upper edge of the view (Illustration of Mine Roof Collapse at the Mammoth Coal Mine North of Sheridan, Wyoming (EOS, 60 (3), p. 28)). I might be mistaken of the exactspot, but the slightly elongated `collapse'

Walter M. Small

1979-01-01

124

Choosing the Right Roof.  

ERIC Educational Resources Information Center

Offers tips for selecting roofing products for new or renovated buildings. Examines various site-specific design parameters such as building life, climatic exposure, water drainage, traffic resistance, and insurer's requirements. Notes points to address in preparing clear, detailed, and well-conceived specifications. (GR)

Evans, Jeff

1999-01-01

125

Green roofs: potential at LANL  

Microsoft Academic Search

Green roofs, roof systems that support vegetation, are rapidly becoming one of the most popular sustainable methods to combat urban environmental problems in North America. An extensive list of literature has been published in the past three decades recording the ecological benefits of green roofs; and now those benefits have been measured in enumerated data as a means to analyze

Pacheco; Elena M

2009-01-01

126

Cool Roofs at Pomona College  

Microsoft Academic Search

The energy efficiency of a building is directly related to the heat transfer between the building and the outside environment. In order to limit the heat transfer to the building by solar radiation cool roofs have been developed which increase the solar reflectivity of roofs. This report investigates the potential application of high reflectivity coatings to roofs at Pomona College

Jeremiah M Steuterman

2012-01-01

127

High-Tech Roof Management.  

ERIC Educational Resources Information Center

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

Benzie, Tim

1997-01-01

128

Two-phase ammonia thermal bus performance  

NASA Astrophysics Data System (ADS)

This paper describes the results of a series of tests that explored the performance of an ammonia heat transport system being developed for future spacecraft applications. It was found that the self-controlling system maintained stable evaporative cold plate temperatures over a wide range of heat loads and heat sink temperatures. The ability of the system to control heat load temperatures during burst power inputs to the evaporator was demonstrated. It was shown that the system required no thermal conditioning or special procedures to start; and reached set point control temperatures within 3.5 minutes of startup under heat load. It was also shown that set point temperatures could be changed and set point control maintained during system operation.

Kramer, Ted J.; Myron, Donald L.; McHale, Michael P.

1988-06-01

129

Thermal Performance of the SNS Cryomodule  

NASA Astrophysics Data System (ADS)

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

Daly, E. F.; Hogan, J. P.; Campisi, I. E.; Drury, M.; Machie, D.; Preble, J.; Rode, C. H.; Whitlatch, T.; Wilson, K. M.; Wiseman, M.

2004-06-01

130

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

Microsoft Academic Search

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

A. W. McKenzie

1982-01-01

131

Wind induced airflow through lightweight pitched roof constructions: Test roof element - measurements and model validation  

Microsoft Academic Search

SUMMARY: In the case of non ventilated compact roofs the wind tightness of the construction is usually warranted by a windproof underlay membrane and the flow resistance of the thermal insulation, as well as sealed eave and ridge details. Because of the current construction practice of wind tight layers in Austria there are numerous small leakages in the eaves, the

Christoph Deseyve; Thomas Bednar

132

Thermal performance of the Brookhaven natural thermal storage house  

NASA Astrophysics Data System (ADS)

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.

133

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

134

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

135

Low pressure steam turbine thermal performance improvements  

SciTech Connect

The turbine thermal performance improvement program represents a pioneering effort by the Electric Power Research Institute to find practical, cost effective means to improve the heat rate of nuclear and fossil units by optimizing the blading elements and exhaust region of the turbine flowpath. Utilities who operate with worn or eroded flowpath components can now seek to offset a portion of the capital expense of purchasing new blade rows or diaphragms by replacing them with designs of improved efficiency. The approach developed as part of the EPRI-sponsored program is to analyze in detail the internal flow in stages and exhaust hoods with advanced 3-D Computational Fluid Dynamic (CFD) programs, and use this analysis as a basis for redesign of these components. These computational tools were not available to the turbine manufacturers when these units were originally designed. This paper outlines the approach currently being applied in EPRI Program RP3648-1 titled {open_quotes}Technology Development for Reducing Exhaust Hood Losses and Improving the Performance of Turbine Blades.{open_quotes} The approach is based on the combined application of full-scale field traverse tests with state-of-art computational fluid dynamics (CFD). The program goal is to develop the means for selecting practical strategies to improve blading efficiency and recover a portion of the exhaust energy within several commonly used exhaust hood designs. In each application, the CFD analysis is used to assess the potential payback versus cost of specific hood and/or blading modifications.

McCloskey, T. [Electric Power Research Institute, Palo Alto, CA (United States); Dewey, R.; Hesler, S. [Stress Technology Inc., Rochester, NY (United States)] [and others

1996-05-01

136

Mine roof drill bits that save money  

SciTech Connect

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

Ford, L.M.

1982-04-01

137

Insulation for built-up roofing systems  

Microsoft Academic Search

Thermal and mechanical properties are discussed for insulating materials for built-up roofing systems, the various materials including fiberboard, perlite, fiberglass, cellular glass, foamed urethane, perlite\\/urethane, fiberglass\\/urethane, extruded polystyrene, molded polystyrene, sprayed urethane foam, poured insulating concrete, and compacted thermosetting fill. An example calculation of the overall coefficient of heat transfer is given, and criteria for selecting insulation are presented. (PMA)

1977-01-01

138

BENEFITS OF BIM IN THE THERMAL PERFORMANCE MANAGEMENT  

Microsoft Academic Search

The importance of analysing thermal performance in building design has grown, but it is still often done using simple static calculations or estimates. Accurate dynamic thermal simulation software have been available already for decades, but these tools are still not widely used by practitioners in building projects. The main barrier of wider usage of dynamic thermal analysis methods has been

Tuomas Laine; Reijo Hänninen; Antti Karola

139

Heating-season thermal performance of the Brookhaven house  

NASA Astrophysics Data System (ADS)

In the Brookhaven Natural Thermal Storage House, a superinsulated envelope, passive solar collectors, and a variety of energy conservation methods are utilized. The thermal performance of the house is evaluated from the data acquired during the 80-81 heating season. The thermal exchange relating to heat loss and gain from the living spaces passive solar contributions, and the thermal storage of the structure are identified and quantified. Several thermal performance ratios and correlation factors are introduced. The average diurnal characteristics of these parameters are then tabulated, and their monthly average hourly values are plotted. Finally, the overall seasonal factors are identified and analyzed.

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

140

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

141

Thermal design and performance of HAMSAT  

Microsoft Academic Search

HAMSAT is a micro-satellite for providing satellite-based Amateur Radio services to the national as well as the international community of Amateur Radio Operators (HAMs). Micro-satellites (less than 100kg) are becoming increasingly utilized as an economical means of experimentation and research in orbit. The thermal control of micro-satellite presents unique challenges to the thermal engineer since the mass; power and volume

K. Badari Narayana; V. Venkata Reddy

2007-01-01

142

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

143

The Benefits of Preventive Roof Maintenance.  

ERIC Educational Resources Information Center

Explains how to convince school administration of the importance of roof-maintenance programs as a way of extending roof life and saving money, even in the presence of roof warranties. Discusses techniques for evaluating the cost benefits of roof maintenance and the importance of creating a roof historical file. (GR)

Kalinger, Peter

1998-01-01

144

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

145

Performance evaluation of molten salt thermal storage systems  

Microsoft Academic Search

The thermal performance of the molten salt thermal storage system located at the Central Receiver Test Facility (CRTF) was measured. The 7-MWht system is composed of a hot storage tank containing molten nitrate salt at a temperature of 1050\\/degree\\/F (566\\/degree\\/C) and a cold tank containing 550\\/degree\\/F (288\\/degree\\/C) salt with associated valves and controls. The thermal performance of this system was

G. J. Kolb; U. Nikolai

1988-01-01

146

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

147

Thermal performance of thermoplastic natural rubber solar collector  

Microsoft Academic Search

The paper presents the thermal performance of a solar collector with TPNR (thermoplastic natural rubber) tubing as the absorber plate. A commercial blend of TPNR (dynamically vulcanised natural rubber—DVNR 9011) was used as the absorber plate which was of the parallel type and satisfies the test conditions indicated by the standard GB 4271-84. The values of the thermal performance parameters

K. Sopian; R. Zulkifli; J. Sahari; M. Y. Othman

2002-01-01

148

Attic testing at the Roof Research Center: Initial results  

SciTech Connect

In 1990, a series of tests was performed on residential attics using an attic test module built to permit research to be accomplished on a number of issues related to attics. This test module was used in the Large Scale Climate Simulator (LSCS) at the Roof Research Center. This combination of test module and LSCS permitted the Center to perform a number of studies under closely controlled interior and climatic conditions including: evaluation of uninsulated attic performance and comparison with previously published results, evaluation of the thermal performance of the attic with loose-fill fiberglass insulation, and the identification of heat loss due to convective air movement through the loose-fill insulation under simulated winter conditions. Testing, in general, showed reasonable agreement with previously published results for each of the above areas of investigation. Thermal performance improved markedly with the installation of the loose-fill insulation. However, the thermal performance of the loose-fill fiberglass insulation tested under winter conditions declined by as much as a factor of two as the temperature difference across the insulation increased. This decline in thermal performance is attributed to the initiation of convection through the insulation as the temperature declines. These findings were documented by both energy flow analysis using the LSCS guarded hot box and infrared scans of the insulation surface in the attic. It should be noted that the present experiments were performed with one type of loose-fill fiberglass insulation. Similar results would be expected for other products that have similar air flow and thermal properties. However, further testing is required to document the performance of the full range of insulations currently available. 4 refs., 8 figs., 4 tabs.

Wilkes, K.E.; Wendt, R.L.; Delmas, A.; Childs, P.W.

1991-01-01

149

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

E-print Network

LBNL-42871 BS-400 Proceedings of Thermal VII, Thermal Performance of the Exterior Envelopes locations. The user describes the physical, thermal and optical properties of the windows in each of the house. The RESFEN program then models a prototypical house for that location and calculates the energy

150

Investigation of the Mechanical Performance of Compliant Thermal Barriers  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

151

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

152

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

153

Space Shuttle Orbiter - Reusable surface insulation subsystem thermal performance  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

154

Exploring Tomorrow's Technology in Roofing  

Microsoft Academic Search

Extensive greenroof technology has been tried and proven in Europe more than 30 years but has not been fully developed for North American climates. Perennial plant ground covers and shallow growing substrates on roofs: 1) improve energy efficiency by reducing interior temperature fluctuations, 2) significantly extend roof membrane life, 3) ameliorate storm water run off, 4) provide beauty & wildlife

John W. White

155

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

156

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

157

Window performance for human thermal comfort  

SciTech Connect

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

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

2000-07-01

158

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

159

Finding Parameters by Tabu Search Algorithm to Construct a Coupled Heat and Mass Transfer Model for Green Roof  

NASA Astrophysics Data System (ADS)

Green roof has the advantage to lower building temperature; therefore it has been applied a lot nowadays to indoor temperature adjustment. This study builds a coupled heat and mass transfer model, in which the water vapor in the substrate is taken into consideration, based on the concept of energy balance. With the parameters optimized by Tabu search algorithm, data from the experiment is used to validate the model. In the study, both the model and the experimental green roof of this study consist of four layers: canopy, substrate, drainage and concrete rooftop. Heat flux of each layer is calculated in the model, using energy balance equations as well as some numerical methods to simulate water-related thermal effect in soil, to see the heat transfer process. The experiment site locates on the rooftop of Hydrotech Research Institute, National Taiwan University, Taiwan. Since the material of the substrate layer has high porosity, the results show a contradiction of energy conservation when neglecting the influence of water. It is found that the parameters identified by Tabu search seem reasonable for the experiment. The main contribution of the study is to construct a thermal model for green roof with parameter optimization procedure, which can be used as an effective assessment method to quantify the heat-reduced performance of green roof on the underlying building.

Chen, P.; Tung, C.

2012-12-01

160

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

161

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

162

Performance evaluation of molten salt thermal storage systems  

Microsoft Academic Search

The molton salt thermal storage system located at the Central Receiver Test Facility (CRTF) was recently subjected to thermal performance tests. The system is composed of a hot storage tank containing molten nitrate salt at a temperature of 1050 F and a cold tank containing 550 F salt with associated valves and controls. It is rated at 7 MWht and

G. J. Kolb; U. Nikolai

1987-01-01

163

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

164

Assessment of Relevant Physical Phenomena Controlling Thermal Performance of Nanofluids  

E-print Network

Assessment of Relevant Physical Phenomena Controlling Thermal Performance of Nanofluids Majid thermal conductivity of nanofluids. Through an investigation, a large degree of randomness and scatter has and lower bounds are developed for steady-state conduction in stationary nanofluids. Comparisons between

Bahrami, Majid

165

Can wet roof insulation be dried out  

SciTech Connect

Nondestructive techniques are being widely used to locate wet insulation in compact roofing systems. Now that wet insulation can be found, breather vents and so called ''breathable'' membranes are being promoted to dry out wet insulation, thereby recovering its thermal effectiveness. Exposure tests in New Hampshire indicate that the above venting methods are all rather ineffective in drying sealed specimens of perlite and fibrous glass roof insulation. It would take many decades to dry specimens at the rates measured over the past two years. Cross-ventilation within the insulation increased the rate of drying. For perlite insulation, the faster rate would still result in a drying time measured in decades. For fibrous glass insulation, the drying time was reduced to 13 years. The authors have succeeded in drying fibrous glass insulation in a roof by removing the water with a vacuum cleaner. In a series of tests with a total duration of 134 h, about 0.42 m/sup 3/ (110 gal) of water was removed from a 17-m/sup 2/ (180-ft/sup 2/) area of 38-mm (1.5-in.)-thick insulation. Before the water was removed the insulation had only 21 percent of its dry insulating ability; afterward it had 83 percent.

Tobiasson, W.; Coutermarsh, B.; Greatorex, A.; Korhonen, C.

1981-12-01

166

Can wet roof insulation be dried out  

SciTech Connect

Nondestructive techniques are being widely used to locate wet insulation in compact roofing systems. Now that wet insulation can be found, breather vents and so-called breathable membranes are being promoted to dry out wet insulation, thereby recovering its thermal effectiveness. Exposure tests in New Hampshire indicate that the above venting methods are all rather ineffective in drying sealed specimens of perlite and fibrous glass roof insulation. It would take many decades to dry our specimens at the rates measured over the past two years. Cross-ventilation within the insulation increased the rate of drying. For perlite insulation, the faster rate would still result in a drying time measured in decades. For fibrous glass insulation, the drying time was reduced to 13 years. Fibrous glass insulation in a roof was dried by removing the water with a vacuum cleaner. In a series of tests with a total duration of 134 h, about 0.4 2 m/sup 3/ (110 gal) of water was removed from a 17-m/sup 2/ (180-ft/sup 2/) area of 38-mm (1.5-in.)-thick insulation. Before the water was removed the insulation had only 21% of its dry insulating ability; afterward it had 83%.

Tobiasson, W.; Korhonen, C.; Coutermarsh, B.; Greatorex, A.

1983-01-01

167

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

168

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

169

NISTIR 7482 Thermal Performance of Fire Resistive Materials  

E-print Network

Dale P. Bentz #12;NISTIR 7482 Thermal Performance of Fire Resistive Materials II. A Multi-Layer One-Dimensional Heat Transfer Model for Fire Resistive Materials Protecting a Substrate Kuldeep R. Prasad Dale P. Bentz

Bentz, Dale P.

170

NISTIR 7576 Thermal Performance of Fire Resistive Materials III.  

E-print Network

Dale P. Bentz Leonard M. Hanssen Boris Wilthan #12;ii NISTIR 7576 Thermal Performance of Fire Resistive Materials III. Fire Test on a Bare Steel Column Dale P. Bentz Building and Fire Research Laboratory National

Bentz, Dale P.

171

Hydrological Modelling and Parameter Identification for Green Roof  

NASA Astrophysics Data System (ADS)

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

Lo, W.; Tung, C.

2012-12-01

172

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

173

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.

174

Cryogenic thermal distortion performance characterization for the JWST ISIM structure  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Structure is a precision optical metering structure for the JWST science instruments. Optomechanical performance requirements place stringent limits on the allowable thermal distortion of the metering structure between ambient and cryogenic operating temperature (~35 K). This paper focuses on thermal distortion testing and successful verification of performance requirements for the flight ISIM Structure. The ISIM Structure Cryoset Test was completed in Spring 2010 at NASA Goddard Space Flight Center in the Space Environment Simulator Chamber. During the test, the ISIM Structure was thermal cycled twice between ambient and cryogenic (~35 K) temperatures. Photogrammetry was used to measure the Structure in the ambient and cryogenic states for each cycle to assess both cooldown thermal distortion and repeatability. This paper will provide details on the post-processing of the metrology datasets completed to compare measurements with performance requirements.

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

2011-10-01

175

Comparing Microchannel Technologies to Minimize the Thermal Stack and Improve Thermal Performance in Hybrid Electric Vehicles  

Microsoft Academic Search

Hybrid electric vehicles for military applications require advanced cooling to ensure peak power electronics performance and reliability. Two methods of reducing overall thermal resistivity by integrating microchannel coolers into the power electronics thermal stack are explored. The first approach involves silicon manifold microchannel coolers with direct fluid impingement on the semiconductor die. The second involves fabricating standard, parallel microchannels into

Nicholas R. Jankowski; Lauren Everhart; Brian Morgan; Bruce Geil; Patrick McCluskey

2007-01-01

176

LCD display screen performance testing for handheld thermal imaging cameras  

NASA Astrophysics Data System (ADS)

Handheld thermal imaging cameras are an important tool for the first responder community. As their use becomes more prevalent, it will become important for a set of standard test metrics to be available to characterize the performance of these cameras. A major factor in the performance of the imagers is the quality of the image on a display screen. An imager may employ any type of display screen, but the results of this paper will focus on those using liquid crystal displays. First responders, especially firefighters, in the field rely on the performance of this screen to relay vital information during critical situations. Current research on thermal imaging camera performance metrics for first responder applications uses trained observer tests or camera composite output signal measurements. Trained observer tests are subjective and composite output tests do not evaluate the performance of the complete imaging system. It is the goal of this work to develop a non-nondestructive, objective method that tests the performance of the entire thermal imaging camera system, from the infrared destructive, sensor to the display screen. Application of existing display screen performance metrics to thermal imaging cameras requires additional consideration. Most display screen test metrics require a well defined electronic input, with either full black or white pixel input, often encompassing detailed spatial patterns and resolution. Well characterized thermal inputs must be used to obtain accurate, repeatable, and non-destructive display screen measurements for infrared cameras. For this work, a thermal target is used to correlate the measured camera output with the actual display luminance. A test method was developed to determine display screen luminance. A well characterized CCD camera and digital recording device were used to determine an electro-optical transfer function for thermal imaging cameras. This value directly relates the composite output signal to the luminance of the display screen, providing a realistic characterization of system performance.

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

2006-05-01

177

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

178

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

SciTech Connect

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

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

1998-06-01

179

Heating and cooling performance of a thermal envelope house  

Microsoft Academic Search

Experimental data are presented from an eight-month long independent study of a thermal envelope house located in Canton, Georgia. The experimental data cover both the heating and cooling performance of the house. Sufficient data and analysis are presented to answer many of the questions being raised concerning the performance of this design. Theories are provided on the effectiveness of the

J. M. Akridge; C. C. Benton; D. W. Abrams

1980-01-01

180

Thermal performance of a double-envelope house  

Microsoft Academic Search

An evaluation is made of the thermal performance of a double envelope house of Ekose's design built in Middletown, Rhode Island. Performance monitoring in the heating season showed that the requirements for auxiliary heat are very low, about 2.1 Btu per square foot or floor space per degree day. Design changes are identified which could reduce the heating needs of

G. Dennehy; R. F. Jones

1982-01-01

181

Thermal performance of an envelope house in a cold climate  

Microsoft Academic Search

Presented are thermal performance data on a double-shell or envelope passive solar residence. The space between the inner and outer shell was instrumented with home-made heated anemometers that were sensitive to air flows in the 0 to 0.5 m-sec⁻¹ range. A partitioned heat balance on the inner and outer shell allowed conclusions to be drawn about the relative thermal contributions

Fowlkes

1982-01-01

182

Thermal performance of fiberglass and cellulose attic insulations  

Microsoft Academic Search

A series of experiments has been completed on the thermal performance of fiberglass and cellulose attic insulations under winter conditions using an attic test module in a guarded hot box facility. Experiments with one type of loose-fill fiberglass insulation showed that the thermal resistance at large temperature differences (70 to 76°F) was about 35 to 50% less than at small

K. E. Wilkes; P. W. Childs

1992-01-01

183

Thermal Insulation Performance in the Process Industries: Facts and Fallacies  

E-print Network

THERMAL INSULATION PERFORMANCE IN 'mE PROCESS INDUSTRIES: FACTS AND FALLACIES R.P. Tye Dynatech RID Company, Cambridge, MA, U.S.A. ABSTRACT The efficient use of thermal insulation materials and systems for design of cryogenic and elevated... -- Voids, Cracks and Environment -- Type and Pressure of Gas, Moisture Irregular Geometry Pick-Up and Retention Anisotropy -- Preferred Orientation of Orientation -- Direction of Heat Flow Fibrous and Layered Products Shrinkage -- Dimensional, Density...

Tye, R. P.

184

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

NASA Astrophysics Data System (ADS)

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

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

2007-09-01

185

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

Microsoft Academic Search

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

Ronnen Levinson; Hashem Akbari

2010-01-01

186

Thermal Performance Testing of EMU and OSS Liquid Cooling Garments  

NASA Technical Reports Server (NTRS)

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

Rhodes, Richard; Bue, Grant; Hakam, Mary

2012-01-01

187

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

188

Development of a low coal, automated remote controlled resin cartridge inserter, roof bolt bender\\/inserter, roof bolt spin\\/thrust\\/hold assembly. Final technical report  

Microsoft Academic Search

This report describes the activities conducted in the development and testing of a bolter module that performs all functions required to install resin-grouted roof bolts in low coal. The program was conducted in nine phases: Phase I required the establishment of design concepts and a study of the system effects of module installation on a variety of existing roof bolters,

Ems

1981-01-01

189

Duct thermal performance models for large commercial buildings  

SciTech Connect

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

Wray, Craig P.

2003-10-01

190

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

191

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

192

Thermal performance of the CrIS passive cryocooler  

NASA Astrophysics Data System (ADS)

The configuration, performance, and test validation of a passive radiant cooler for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Crosstrack Infrared Sounder (CrIS) Instrument are presented. The cooler is required to provide cryogenic operation of IR focal planes. The 11 kg device, based on prior ITT Industries Space Systems Division coolers, requires virtually no power. It uses multiple thermally isolated cooling stages, each with an independent cryoradiator, operating at successively colder temperatures. The coldest stage, with a controlled set point at 81 K, cools a longwave IR (LWIR) focal plane. An intermediate stage, with a 98 K control point, cools detectors operating in MWIR and SWIR spectral regions. The warmest stage includes a fixed, integral earth shield that limits the thermal load from the earth in the NPOESS Operational Low-earth Orbiting (LEO) orbit. A study of the thermal balance and loads analysis used to evaluate the predicted cooler performance is discussed. High performance margins have been retained throughout the cooler development, fabrication and test phases of the program. The achievable in-orbit temperatures for this cooler are anticipated to be 73 K for the LWIR cooling stage and 91 K for the midwave IR (MWIR)/shortwave IR (SWIR) stage. Test results from two iterations of thermal vacuum verification testing are presented. Lessons learned from the first test, which failed to produce the predicted performance are included. The thermal model of the cooler and test configuration was used to identify deficiencies in the test targets resulting in unexpected heat loads. Corrective action was implemented to remove the heat leaks and a second test verified both the cooler performance and the correlation of the detailed thermal model.

Ghaffarian, B.; Kohrman, R.; Magner, A.

2006-02-01

193

Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions  

Microsoft Academic Search

BackgroundGreen roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in

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

2010-01-01

194

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

195

Integrated heat pipe-thermal storage system performance evaluation  

NASA Technical Reports Server (NTRS)

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

1987-01-01

196

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

197

Thermal modeling and performance analysis of a thermoacoustic refrigerator  

NASA Astrophysics Data System (ADS)

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

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

2003-08-01

198

Architectural designs and thermal performances of school sports-halls  

Microsoft Academic Search

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

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

2003-01-01

199

PERFORMANCE OF A CONCENTRATING PHOTOVOLTAIC/THERMAL SOLAR COLLECTOR  

E-print Network

loosest sense to describe semi-transparent PV panels such as dye- sensitised solar panels usedPERFORMANCE OF A CONCENTRATING PHOTOVOLTAIC/THERMAL SOLAR COLLECTOR Joe S Coventry Centre efficiency of 68%. The impact of non-uniform illumination on the solar cells is investigated using purpose

200

Performance of a thermal envelope house in Michigan  

Microsoft Academic Search

Monitored performance of the first thermal envelope house in Michigan is presented. Configuration of the house is outlined. The average weather conditions during the 27-day period in late February thru March, 1980 (during which measurements were taken) are quantified. Data are taken and correlated so as to determine the statistically probable mean temperatures of various parts of the envelope. From

Rubyan

1980-01-01

201

Thermal Performance of a Building Envelope - A Probabilistic Approach  

Microsoft Academic Search

A probabilistic model of the thermal performance of a building envelope is proposed. The model predicts the probability density function of the heat loss over a specified period of time on the basis of the design parameters of the house, climatic characteristics of the site as well as the air change rate due to mechanical or natural ventilation. Reliability of

Krystyna Pietrzyk

2010-01-01

202

Solar Roof Cooling by Evaporation  

E-print Network

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

Patterson, G. V.

1980-01-01

203

Thermal performance of a double-envelope house  

NASA Astrophysics Data System (ADS)

An evaluation is made of the thermal performance of a double envelope house of Ekose's design built in Middletown, Rhode Island. Performance monitoring in the heating season showed that the requirements for auxiliary heat are very low, about 2.1 Btu per square foot or floor space per degree day. Design changes are identified which could reduce the heating needs of the house are due primarily to the excellent insulative value of the double shell.

Dennehy, G.; Jones, R. F.

1982-06-01

204

Thermal performance analysis of a double-envelope house  

Microsoft Academic Search

An evaluation is made of the thermal performance of a double-envelope house of Ekose'a design built in Middletown, Rhode Island. Performance monitoring in the heating season showed that the requirements for auxiliary heat are very low, about 2.1 Btu per square foot of floor space per degree-day. Design changes are identified which could reduce the heating requirement even further. It

G. Dennehy; R. F. Jones

1982-01-01

205

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

NASA Technical Reports Server (NTRS)

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

Pippin, Gary; Stuckey, Wayne; Hemminger, Carol

1993-01-01

206

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

207

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

PubMed

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

208

IDENTIFYING ROOF FALL PREDICTORS USING FUZZY CLASSIFICATION  

SciTech Connect

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

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

2010-02-22

209

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2012 CFR

...Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND...opening dimensions and roof stresses; or (2) Tests which...opening dimensions and roof stresses as the area where the...

2012-07-01

210

30 CFR 75.204 - Roof bolting.  

Code of Federal Regulations, 2013 CFR

...Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND...opening dimensions and roof stresses; or (2) Tests which...opening dimensions and roof stresses as the area where the...

2013-07-01

211

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

212

TOD Performance Model for Staring Thermal Imager with Machine Vision  

NASA Astrophysics Data System (ADS)

A triangle orientation discrimination threshold(TOD) performance theoretical model is derived for the staring thermal imager based on machine vision. Specifically, how to obtain the TOD curve based on machine vision is briefly described. The spatial frequency distribution of the triangle test pattern is first determined. The transform and response characteristics of the non-periodic triangle pattern and its background clutter through machine vision-based thermal imager are analyzed. The three-dimensional matched filter is adopted to characterize quantitatively the spatial and temporal integration of image enhancement algorithms to the output triangle pattern signal, various noise components and background clutter, and the signal-to-interference ratio (SIR) of the triangle pattern output image is derived for the staring thermal imager based on machine vision. Then, the TOD performance theoretical model is established by assuming that the output SIR is equal to the threshold SIR75% determined by the discrimination criteria of machine vision. Preliminary simulation and experimental results show that this theoretical model can give reasonable prediction of the TOD performance curve for staring thermal imagers based on machine vision.

Wu, Yingxia; Wang, Xiao-Rui; Lin, Hongjie; Zhang, Jianqi

2010-01-01

213

Media depth influences Sedum green roof establishment  

Microsoft Academic Search

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

Kristin L. Getter; D. Bradley Rowe

2008-01-01

214

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

Microsoft Academic Search

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

Syd S. Peng

2005-01-01

215

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

Microsoft Academic Search

Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal, 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

Syd S. Peng

2002-01-01

216

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.

217

Building roof with solar collector  

Microsoft Academic Search

A roof or wall structure comprises a support framework including battens or the like and a plurality of tile-like solar heat collectors mounted thereon. The solar heat collectors have respective cavities therein within which respective heater coils or the like are disposed. The heater coils have inlets and outlets which are in fluid-flow connection with channels in the battens.

Vinz

1980-01-01

218

DOE's Roof Savings Calculator (RSC)  

E-print Network

: · Albedo engineering for solar radiation management ­ increasing Earth's reflectance Examples: cloud Steven Chu, Daily Show, July 21, 2009 #12;Cool roof context Goal to address climate change, manage Earth's heat budget (amount of Earth's heat from the sun minus amount reflected into space) 2 pillars of geo-engineering

Wang, Xiaorui "Ray"

219

An inverted roof with mineral wool  

Microsoft Academic Search

Eighteen months’ monitoring is reported of an experimental roof on the building physics laboratory of the Catholic University of Leuven, Belgium. The existing lightweight roof with roofing felt finish, built some twenty years before, was covered with water?repellent mineral wool slabs, of which only the edge slabs were bonded. The results showed poor water?repellent quality of the MW slab, leading

H. L. Hens; F. Vaes

1986-01-01

220

IMPULSE---an advanced, high performance nuclear thermal propulsion system  

SciTech Connect

IMPULSE is an advanced nuclear propulsion engine for future space missions based on a novel conical fuel. Fuel assemblies are formed by stacking a series of truncated (U, Zr)C cones with non-fueled lips. Hydrogen flows radially inward between the cones to a central plenum connected to a high performance bell nozzle. The reference IMPULSE engine rated at 75,000 lb thrust and 1800 MWt weighs 1360 kg and is 3.65 meters in height and 81 cm in diameter. Specific impulse is estimated to be 1000 for a 15 minute life at full power. If longer life times are required, the operating temperature can be reduced with a concomitant decrease in specific impulse. Advantages of this concept include: well defined coolant paths without outlet flow restrictions; redundant orificing; very low thermal gradients and hence, thermal stresses, across the fuel elements; and reduced thermal stresses because of the truncated conical shape of the fuel elements.

Petrosky, L.J.; Disney, R.K.; Mangus, J.D. (Advanced Programs Department, Westinghouse Electric Corporation, P.O. Box 158, Madison, Pennsylvania 15663-0158 (United States)); Gunn, S.A.; Zweig, H.R. (Rocketdyne Division, Rockwell International Corporation, 6633 Canoga Avenue, P.O. Box 7922, Canoga Park, California 91309-7922 (United States))

1993-01-10

221

Attic testing at the Roof Research Center: Initial results  

Microsoft Academic Search

In 1990, a series of tests was performed on residential attics using an attic test module built to permit research to be accomplished on a number of issues related to attics. This test module was used in the Large Scale Climate Simulator (LSCS) at the Roof Research Center. This combination of test module and LSCS permitted the Center to perform

K. E. Wilkes; R. L. Wendt; A. Delmas; P. W. Childs

1991-01-01

222

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

223

Effects of building roof greening on air quality in street canyons  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

224

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

225

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

226

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

SciTech Connect

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

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

1998-06-01

227

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

228

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

229

Development of a roof competence tester. Report for 18 August 1980-19 March 1985  

Microsoft Academic Search

A four-year program was completed to develop a technique for measuring roof competence in underground coal mines. The preferred technique employs a tracer gas that is injected into a roof borehole drilled near the working face. The tracer gas performs the dual purpose of determining the pressure loss rate from the borehole and of marking the diffusion pattern of the

Czirr

1985-01-01

230

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

231

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

SciTech Connect

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

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

1987-09-15

232

Background character research for synthetical performance of thermal imaging systems  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

233

Some aspects of the thermal performance of indigenous powder insulators  

NASA Astrophysics Data System (ADS)

The thermal performances of indigenously available powder materials such as, exfoliated vermiculite, opaque and non-opaque precipitated silica have been studied under various conditions: ie mesh size, packing density, interstitial gas pressure etc., and compared with that of expanded perlite. In this connection scanning electron microscope photographs of these samples have also been taken to have a preliminary information regarding the structure of the materials.

Maiti, C. R.

234

Mastin double-envelope house: a thermal performance evaluation  

Microsoft Academic Search

An evaluation is made of the thermal performance of a double-envelope house of Ekose'a design built by Robert Mastin in Middletown, Rhode Island. The home has two shells with an air space between through which air can circulated. Monitoring of the house in the heating season showed that the requirements for auxiliary heat are very low, about 2.1 Btu per

R. F. Jones; G. Dennehy

2009-01-01

235

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

E-print Network

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

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

2013-01-01

236

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

237

Lithium-ion capacitors: Electrochemical performance and thermal behavior  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

238

Analysis of thermal performance of penetrated multi-layer insulation  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

239

Predictive Service Life Tests for Roofing Membranes  

NASA Astrophysics Data System (ADS)

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

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

2002-09-01

240

Isopods Failed to Acclimate Their Thermal Sensitivity of Locomotor Performance during Predictable or Stochastic  

E-print Network

do abrupt changes. To explore this possibility, we exposed terrestrial isopods (Porcellio scaberIsopods Failed to Acclimate Their Thermal Sensitivity of Locomotor Performance during Predictable expectation, thermal treatments did not affect the thermal sensitivity of locomotion; isopods from all

Angilletta, Michael

241

Roof Polishing of Optical Fibers  

NASA Technical Reports Server (NTRS)

Bevealed tip gives optimum coupling efficiency. Abrasive tape used to grind tip of optical fiber. Grinding force depends on stiffness of optical fiber. "Roof" shape on end of optical glass fiber increases efficiency which couples laser light. End surface angle of 65 degrees with perpendicular required for optimum coupling. Since fiber and tape are light in weight and compliant, ridge defect-free, and chipping on fiber edge totally eliminated.

Dholakia, A. R.

1985-01-01

242

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

SciTech Connect

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

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

1998-07-01

243

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

244

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...

245

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...

246

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

247

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

248

Thermal Performance of Wind Turbine Power System's Engine Room  

NASA Astrophysics Data System (ADS)

Greatly expanded use of wind energy has been proposed to reduce dependence on fossil and nuclear fuels for electricity generation. For wind turbine power generation, as a mature technology in the field of wind power utilization, its large-scale deployment is limited by the cooling technology. Therefore, the temperature distribution of the wind turbine power generation is a key issue for the design of the cooling system. It is because the characteristics of cooling system have a great effect on the performance of the wind turbine power generation. Based on some assumptions and simplifications, a thermal model is developed to describe the heat transfer behavior of wind turbine power system. The numerical calculation method is adopted to solve the governing equation. The heat generation and heat flux are investigated with a given operating boundary. The achieved results can be used to verify whether the cooling system meets the design requirements. Meanwhile, they also can reveal that among the influencing factors, the meteorological conditions, generated output and operation state as well seriously influence its thermal performance. Numerical calculation of the cooling system enables better understanding and results in performance improvement of the system.

Liu, Zhili; Jiang, Yanlong; Zhou, Nianyong; Shi, Hong; Kang, Na; Wang, Yu

249

Manufacture and performance of the thermal-bonding Micromegas prototype  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

250

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

251

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

252

Analytical study of nozzle performance for nuclear thermal rockets  

SciTech Connect

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

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

1991-01-01

253

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

Code of Federal Regulations, 2011 CFR

...internal floating roof (IFR). (a) IFR design requirements. The owner or operator...internal floating roof shall comply with the design requirements in paragraphs (a)(1...liquid-mounted seal. (ii) A metallic shoe seal. (iii) Two continuous...

2011-07-01

254

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

...internal floating roof (IFR). (a) IFR design requirements. The owner or operator...internal floating roof shall comply with the design requirements in paragraphs (a)(1...liquid-mounted seal. (ii) A metallic shoe seal. (iii) Two continuous...

2014-07-01

255

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

Code of Federal Regulations, 2010 CFR

...internal floating roof (IFR). (a) IFR design requirements. The owner or operator...internal floating roof shall comply with the design requirements in paragraphs (a)(1...liquid-mounted seal. (ii) A metallic shoe seal. (iii) Two continuous...

2010-07-01

256

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

Code of Federal Regulations, 2012 CFR

...internal floating roof (IFR). (a) IFR design requirements. The owner or operator...internal floating roof shall comply with the design requirements in paragraphs (a)(1...liquid-mounted seal. (ii) A metallic shoe seal. (iii) Two continuous...

2012-07-01

257

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

Code of Federal Regulations, 2013 CFR

...internal floating roof (IFR). (a) IFR design requirements. The owner or operator...internal floating roof shall comply with the design requirements in paragraphs (a)(1...liquid-mounted seal. (ii) A metallic shoe seal. (iii) Two continuous...

2013-07-01

258

Thermal Performance of a Cryogenic Fluid Management Cubesat Mission  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

259

Green roof vegetation for North American ecoregions: A literature review  

Microsoft Academic Search

A green roof is a vegetated roof or deck designed to provide urban greening for buildings, people, or the environment. Made popular across Europe over the past few decades, green roofs are now becoming more familiar to North Americans as some cities have built green roof pilot projects and adopted incentives for using green roofs or even require their use.

Bruce Dvorak; Astrid Volder

2010-01-01

260

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

SciTech Connect

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

Syd S. Peng

2003-01-15

261

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

SciTech Connect

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

Syd S. Peng

2003-10-15

262

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

SciTech Connect

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

Kehrer, Manfred [ORNL

2011-01-01

263

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

264

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

PubMed

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

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

2011-01-01

265

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

266

Integrated roof wind energy system  

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

267

Thermal performance of fiberglass and cellulose attic insulations  

SciTech Connect

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

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

1992-01-01

268

Thermal performance of fiberglass and cellulose attic insulations  

SciTech Connect

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

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

1992-10-01

269

30 CFR 75.213 - Roof support removal.  

Code of Federal Regulations, 2013 CFR

...Roof bolt torque or tension measurements or the condition of conventional support indicate excessive loading; (2) Roof fractures are present; (3) There is any other indication that the roof is structurally weak; or (4) Pillar recovery has...

2013-07-01

270

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

SciTech Connect

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

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

2007-06-04

271

THERMAL PERFORMANCE OF RADIOACTIVE MATERIAL PACKAGES IN TRANSPORT CONFIGURATION  

SciTech Connect

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

Gupta, N.

2010-03-04

272

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

273

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

274

Ultraviolet radiation testing of roofing systems  

SciTech Connect

The Roof Research Center (RRC), a DOE national user facility planned for construction at Oak Ridge National Laboratory, will be used for studying roof systems subjected to accelerated testing. A review of relevant literature concerning ultraviolet radiation (uv) and related testing and equipment was completed to determine the feasibility of using this proposed facility for artificially-induced ultraviolet weathering of twelve by twelve foot roof systems that will be tested for periods of up to eight weeks. Artificial weathering sources now in use for ultraviolet exposure include carbon-arc and xenon-arc lamps, ultraviolet lamps, and mirrors which concentrate natural solar radiation (EMMAQUA method). The shortest exposure period using these devices for which changes in tensile strength (-9% to +1%) and percent elongation (-29% to -3%) have been observed in roofing materials are: ultraviolet lanps - 2000 hours (approx. =83 days); carbon-arc - 2000 hours; xenon-arc - 2000 hours; EMMAQUA - 300,000 langleys (approx. =75 days exposure in Arizona). An exposure period of only eight weeks is considered to be too short to degrade roof materials of interest with existing weathering sources. Separate ultraviolet exposure outside the Roof Research Canter would be required to evaluate uv sensitivity of the subject roof system. Aged (in-service) roofs could be tested at the Center to determine changes produced during weathering.

Amirkhanian, K.R.; Busching, H.W.

1987-07-01

275

Building integrated solar power generation on roof  

Microsoft Academic Search

This paper reports a new technology of building integrated photovoltaics (BIPV). It uses a solar cell panel array to form a whole building roof to replace traditional southern slope roof. The advantage of the proposed approach over more common adopted rooftop systems is the lower cost, better blend and more aesthetically appealing. This technology has been successfully applied in the

Guoguang Yu; Huiqing Xu; Jicai Ding; Hongshan Xu; Xianbi Xiang; Xianbo Liao

2010-01-01

276

Mine roof drill bits that save money  

Microsoft Academic Search

Sandia National Laboratories, Albuquerque, NM, has developed advanced technology roof bolt drill bits which have demonstrated longer life, higher penetration rates at lower thrust and torque, and lower specific energy than conventional roof bolt drill bits. This is achieved through use of advanced technology cutting materials and novel bit body designs. These bits have received extensive laboratory and mine testing.

Ford

1982-01-01

277

ROOFING PROJECT ODORS How Can EHS Help?  

E-print Network

of exposure found inside buildings during roofing projects. Can Breathing Fumes Cause Cancer? According), there is no direct evidence that inhalation of asphalt roofing odors causes cancer in building occupants. Some epidemiological studies of asphalt works suggests that they may be at a somewhat increased risk for lung cancer

Stephens, Graeme L.

278

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

279

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

SciTech Connect

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

Syd S. Peng

2002-01-15

280

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

Microsoft Academic Search

The thermal envelope house is shown to perform much better than conventional houses without mechanical refrigeration and better than one would expect from most passively cooled houses in the hot-humid climate of Georgia. Peak temperatures inside the house were 8 to 15°F below peak ambient temperatures. Peak inside temperature measured during the test period was 80°F with an outside ambient

J. M. Akridge; C. C. Benton

1981-01-01

281

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

SciTech Connect

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

Yarlagadda, B.S.

1989-04-01

282

Thermal radiant exitance model performance: Soils and forests  

SciTech Connect

Models of surface temperatures of two land surface types based on their energy budgets were developed to simulate the effects of environmental factors on thermal radiant exitance. The performance of these models is examined in detail. One model solves the non-linear differential equation for heat diffusion in solids using a set of submodels for surface energy budget components. The model performance is examined under three desert conditions thought to be a strong test of the submodels. The accuracy of the temperature predictions and submodels is described. The accuracy of the model is generally good but some discrepancies between some of the submodels and measurements are noted. The sensitivity of the submodels is examined and is seen to be strongly controlled by interaction and feedback among energy components that are a function of surface temperature. The second model simulates vegetation canopies with detailed effects of surface geometry on radiant transfer in the canopy. Foliage solar absorption coefficients are calculated using a radiosity approach for a three layer canopy and long wave fluxes are modeled using a view factor matrix. Sensible and latent heat transfer through the canopy are also simulated using, nearby meteorological data but heat storage in the canopy is not included. Simulations for a coniferous forest canopy are presented and the sensitivity of the model to environmental inputs is discussed.

Balick, L.K. [EG& G Energy Measurements Inc., Las Vegas, NV (United States); Smith, J.A. [NASA/Goddard Space Flight Center, Greenbelt, MD (United States). Lab. for Terrestrial Physics

1995-12-31

283

Green roof impact on the hydrological cycle components  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

284

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

285

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

286

An endoscopic, cadaveric analysis of the roof of the fourth ventricle.  

PubMed

We performed endoscopic dissections of the roof of the fourth ventricle in eight fresh human cadaveric heads to characterize the endoscopic anatomy of the roof of the fourth ventricle and the anatomical configuration of the structures forming its roof. We also made three-dimensional (3D) silicone casts of the fourth ventricle in seven formalin-fixed specimens to evaluate the 3D configuration of the structures that create the roof of the fourth ventricle. The roof of the fourth ventricle can be divided into three zones. The upper zone is formed by the superior cerebellar peduncle and superior medullary velum and is associated with the lingula. The middle zone is formed by the inferior cerebellar peduncles and inferior medullary velum and is associated with the nodule in the midline and with the peduncle of the flocculus. The lower zone is formed by the tela choroidea and is associated with the tonsils. The 3D shape of the roof the fourth ventricle resembles that of a rhomboid-based pyramid; the edges of the base represent the borders of the ventricle, and the apex is the cerebellar fastigium. The lateral recess is shaped like a triangular-based pyramid, with its base connected to the cavity of the fourth ventricle and its tip opening into the lateral cerebellomedullary cistern through the foramen of Luschka. Our results may help in the endoscopic exploration of and microsurgical approaches to the fourth ventricle through its roof. PMID:23507044

Salma, Asem; Yeremeyeva, Esmiralda; Baidya, Nishanta B; Sayers, Martin Peter; Ammirati, Mario

2013-05-01

287

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

288

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

289

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

290

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

NASA Astrophysics Data System (ADS)

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

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

1981-09-01

291

Assessment of the performance of ventilated floor thermal storage systems  

SciTech Connect

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

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

1996-11-01

292

Hydrogen recombination kinetics and nuclear thermal rocket performance prediction  

SciTech Connect

The rate constants for the hydrogen three-body collisional recombination reaction with atomic and molecular hydrogen acting as third bodies have been determined by numerous investigators during the past 30 yr, but these rates exhibit significant scatter. The discrepancies in the rate constants determined by different investigators are as great as two orders of magnitude in the temperature range of interest for nuclear thermal rocket (NTR) operation, namely, 2000-3300 K. The impact of this scatter on our ability to predict the specific impulse (I(sub sp)) delivered by a 30-klbf NTR has been determined for chamber pressures and temperatures from, respectively, 20-1000 psia and 2700-3300 K. The variation in I(sub sp) produced by using the different rate constants is as great as 10%, or 100 s. This variation also obscures the influence of chamber pressure on I(sub sp); using fast kinetics, low pressures yield significantly improved performance, while using slow or nominal kinetics, the pressure dependence of I(sub sp) is negligible. Because the flow composition freezes at very small area ratios, optimization of the nozzle contour in the near-throat region maximizes recombination. Vibrational relaxation is found to produce negligible losses in I(sub sp). 36 refs.

Wetzel, K.K.; Solomon, W.C. [Univ. of Illinois, Urbana-Champaign, Urbana, IL (United States)

1994-07-01

293

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

294

Thermal performance of residential duct systems in basements  

NASA Astrophysics Data System (ADS)

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. 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 ducks to an R-value of 0.88 (C x sq. m)/W(100 F x sq. ft x h/BTU) where they are exposed in the basement. To determine the maximum possible reduction in energy use, simulations were run with all ducts insulated to (17.6 C x sq m)/W(100 F x sq. ft x h/BTU) and with no duct leakage. A reduction of energy use by 14% is obtained by using perfect ducts instead of normal ducts.

Treidler, Burke; Modera, Mark

1994-01-01

295

Performance of solar thermal systems with liquid metal MHD conversion  

NASA Astrophysics Data System (ADS)

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

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

1984-06-01

296

Thermal performance of metal-clad fiber Bragg grating sensors  

Microsoft Academic Search

We demonstrate the higher temperature sensitivity of a fiber Bragg grating (FBG) sensor when it is clad with a metal of a large thermal expansion coefficient. With lead (solder) cladding, the sensitivity of Bragg wavelength shift can be enhanced by about five (four) times. A theoretical model was adopted to show quite consistent results. It was found that thermal annealing

Gang-Chih Lin; Likarn Wang; C. C. Yang; M. C. Shih; T. J. Chuang

1998-01-01

297

Predicting performance of coatings under thermal insulation at high temperatures  

SciTech Connect

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

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

1994-10-01

298

Thermal performance of closed two-phase thermosyphon using nanofluids  

Microsoft Academic Search

Nanofluids, stabilized suspensions of nanoparticles typically <100 nm in conventional fluids, are evolving as potential enhanced heat transfer fluids due to their improved thermal conductivity, increase in single phase heat transfer coefficient and significant increase in critical boiling heat flux. In the present paper, we investigate the overall thermal resistance of closed two-phase thermosyphon using pure water and various water

Sameer Khandekar; Yogesh M. Joshi; Balkrishna Mehta

2008-01-01

299

Mechanisms governing the performance of thermal barrier coatings  

Microsoft Academic Search

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

P. K. Wright; A. G. Evans

1999-01-01

300

Thermal performance study of box type solar cooker from heating characteristic curves  

Microsoft Academic Search

The top heat losses that constitute the major losses from the box type solar cooker have a strong influence on the thermal performance. To predict or evaluate the thermal performance of a cooker, the top heat loss coefficient Utw for a water loaded cooker must be known. In the present study, several indoor and outdoor experiments were performed on a

Subodh Kumar

2004-01-01

301

Determining Adaptability Performance of Artificial Neural Network-Based Thermal Control Logics for Envelope Conditions in Residential Buildings  

E-print Network

This study examines the performance and adaptability of Artificial Neural Network (ANN)-based thermal control strategies for diverse thermal properties of building envelope conditions applied to residential buildings. The thermal performance using...

Moon, Jin Woo; Chang, Jae D.; Kim, Sooyoung

2013-07-18

302

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

303

Design considerations for retractable-roof stadia  

E-print Network

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

Frazer, Andrew H., 1981-

2005-01-01

304

Coal Mine Roof Instability: Categories and Causes.  

National Technical Information Service (NTIS)

Coal mine roof failure is categorized according to character, trend, or pattern of occurrence. Two principal categories of failure are proposed--geology related and stress related. Geology-related failure includes both lithology and structure. Each of sev...

N. N. Moebs, R. M. Stateham

1986-01-01

305

Thermal performance analysis according to wood flooring structure for energy conservation in radiant floor heating systems  

Microsoft Academic Search

The aim of this study was to reduce energy consumption, especially heating, in buildings. Improvements in the thermal conductivity of wood flooring, which was considered to decrease heating between floors and the indoor areas, were investigated. Wood flooring components such as solid-wood, high-density fiberboard (HDF), adhesives and polyethylene generally exhibit low thermal conductivity. The thermal conductivity and transfer performance of

Jungki Seo; Jisoo Jeon; Jeong-Hun Lee; Sumin Kim

2011-01-01

306

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

307

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

308

Metal and nutrient dynamics on an aged intensive green roof.  

PubMed

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

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

2014-01-01

309

Roof Coating Procedures and Their Productivity Gains  

E-print Network

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

Bonaby, J.; Schaub, D.

2006-01-01

310

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

311

Hybrid polymer devices for improved thermal control and performance  

NASA Astrophysics Data System (ADS)

Single-mode waveguides based on planar silica have found increasing application in passive optical components such as arrayed waveguide gratings (AWG), couplers, and splitters. Key aspects of these devices are their low insertion losses and relative insensitivity to temperature. Planar polymer waveguides present a complementary technology that is finding deployment in thermally activated components such as thermo-optic switches, variable attenuators and tunable filters. This results from the large thermo-optic effects and low thermal conductivities in polymers that lead to low power, compact and rapid thermal activation.

Norwood, Robert A.

2001-04-01

312

Part A: Assessing the performance of the COMFA outdoor thermal comfort model on subjects performing physical activity  

Microsoft Academic Search

This study assessed the performance of the COMFA outdoor thermal comfort model on subjects performing moderate to vigorous\\u000a physical activity. Field tests were conducted on 27 subjects performing 30 min of steady-state activity (walking, running,\\u000a and cycling) in an outdoor environment. The predicted COMFA budgets were compared to the actual thermal sensation (ATS) votes\\u000a provided by participants during each 5-min interval.

Natasha A. Kenny; Jon S. Warland; Robert D. Brown; Terry G. Gillespie

2009-01-01

313

Liquid storage tank with floating roof structure  

SciTech Connect

In a cylindrical wall storage tank for containing a liquid, said tank is described having a floor, a floatable roof supportable by said contained liquid, said roof including a peripheral seal for engaging the cylindrical wall to maintain a fluid-tight sliding seal therewith, and support means associated with said roof including, the improvement in said tank of, at least one cylindrical guide sleeve extending downwardly from said floatable roof; a shoe depending laterally from said at least one cylindrical guide sleeve's lower end for engaging the tank floor when the level of contained liquid is insufficient to support said floatable roof, said shoe having means forming a passage there through to register a support column and, an elongated support column removably positioned in said at least one cylindrical guide sleeve, of being sufficient length to extend downward beyond the shoe to engage the tank floor, whereby to sustain the floatable roof a predetermined distance above said floor after the contained liquid has drained from the tank.

Vaughn, L.G.

1993-07-27

314

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

315

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

316

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

317

Impact of board variables on the thermal performance of a QFN package  

Microsoft Academic Search

The Quad Flat No-Lead (QFN) package, with its exposed die pad soldered to the printed wiring board (PWB), has a thermal performance highly dependent on the PWB design and thermal environment. This paper documents the impact of the following changes to the PWB on the thermal performance of a 44-lead 9×9 mm QFN package: PWB overall thickness, board area, PWB

Tony Montes de Oca; Bennett Joiner; Thomas Koschmieder

2002-01-01

318

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

319

Thermal/Optical Performance Characteristics of Reflective Light Shelves in Buildings (Revised),  

National Technical Information Service (NTIS)

The purpose of the research was to determine the performance characteristics on commonly used light shelves and to develop a product which would improve the thermal/optical performance of reflective light shelves in buildings. The conclusions reached as a...

P. R. Rittelmann, P. W. Scanlon, A. M. Sain, S. F. Ahmed, J. E. Davy

1985-01-01

320

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

Microsoft Academic Search

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

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

2006-01-01

321

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

322

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

ERIC Educational Resources Information Center

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

Christensen, G.; And Others

323

Automatic Roof Outlines Reconstruction from Photogrammetric Dsm  

NASA Astrophysics Data System (ADS)

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

Nex, F.; Remondino, F.

2012-07-01

324

Surface heat budget on green roof and high reflection roof for mitigation of urban heat island  

Microsoft Academic Search

In this study, the surface temperature, net radiation, water content ratio, etc., of green roofs and high reflection roofs are observed. The heat and water budget are compared to each other. In the daytime, the temperature of the cement concrete surface, the surface with highly reflective gray paint, bare soil surface, green surface and the surface with highly reflective white

Hideki Takebayashi; Masakazu Moriyama

2007-01-01

325

A generic hydrological model for a green roof drainage layer.  

PubMed

A rainfall simulator of length 5 m and width 1 m was used to supply constant intensity and largely spatially uniform water inflow events to 100 different configurations of commercially available green roof drainage layer and protection mat. The runoff from each inflow event was collected and sampled at one-second intervals. Time-series runoff responses were subsequently produced for each of the tested configurations, using the average response of three repeat tests. Runoff models, based on storage routing (dS/dt = I-Q) and a power-law relationship between storage and runoff (Q = kS(n)), and incorporating a delay parameter, were created. The parameters k, n and delay were optimized to best fit each of the runoff responses individually. The range and pattern of optimized parameter values was analysed with respect to roof and event configuration. An analysis was performed to determine the sensitivity of the shape of the runoff profile to changes in parameter values. There appears to be potential to consolidate values of n by roof slope and drainage component material. PMID:23985505

Vesuviano, Gianni; Stovin, Virginia

2013-01-01

326

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

327

Thermal Performance of Composite Flexible Blanket Insulations for Hypersonic Aerospace Vehicles  

NASA Technical Reports Server (NTRS)

This paper describes the thermal performance of a Composite Flexible Blanket Insulation (C.F.B.I.) considered for potential use as a thermal protection system or thermal insulation for future hypersonic vehicles such as the National Aerospace Plane (N.A.S.P.). Thermophysical properties for these insulations were also measured including the thermal conductivity at various temperatures and pressures and the emissivity of the fabrics used in the flexible insulations. The thermal response of these materials subjected to aeroconvective heating from a plasma arc is also described. Materials tested included two surface variations of the insulations, and similar insulations coated with a Protective Ceramic Coating (P.C.C.). Surface and backface temperatures were measured in the flexible insulations and on Fibrous Refractory Composite Insulation (F.R.C.I.) used as a calibration model. The uncoated flexible insulations exhibited good thermal performance up to 35 W/sq cm. The use of a P.C.C. to protect these insulations at higher heating rates is described. The results from a computerized thermal analysis model describing thermal response of those materials subjected to the plasma arc conditions are included. Thermal and optical properties were determined including thermal conductivity for the rigid and flexible insulations and emissivity for the insulation fabrics. These properties were utilized to calculate the thermal performance of the rigid and flexible insulations at the maximum heating rate.

Kourtides, Demetrius A.

1993-01-01

328

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

PubMed

We investigated the fiber Bragg grating (FBG) thermal response in space vacuum thermal environment. The FBGs were packaged with 6061-T6 aluminum. The liquid nitrogen immersion experiment results show that its wavelength shift standard deviation is 0.76 pm for 217 h. The combination effect of vacuum and cryogenic temperature was studied by thermal cycling process in space environment simulator. The FBG sensors show accuracy better than 2% full scale, and the hysteresis errors are below 1%. It proves that these metal packaged FBG sensors can survive and meet the requirement of space measurement. PMID:24387420

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

2013-12-01

329

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

SciTech Connect

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

Akbari, Hashen; Rainer, Leo

2000-11-01

330

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 2year 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

331

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

PubMed

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

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

2014-05-01

332

Performance of thermal barrier coatings in high heat flux environments  

Microsoft Academic Search

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

ROBERT A. MILLER; CHRISTOPHER C. BERNDT

1984-01-01

333

UTILIZING HIGH PERFORMANCE SUPERCOMPUTING FACILITIES FOR INTERACTIVE THERMAL COMFORT ASSESSMENT  

Microsoft Academic Search

We outline the current state of the development of a computational steering environment (CSE) for the interactive simulation and local assessment of indoor thermal comfort. The system consists of a parallel CFD kernel, a fast 3D mesh generator and a virtual reality-based visualization component. The numeri- cal method is based on a lattice Boltzmann algorithm with extensions for simulations of

Christoph van Treeck; Petra Wenisch; Andre Borrmann; Michael Pfaffinger; Nikola Cenic; Ernst Rank

2007-01-01

334

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

PubMed

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

Mandal, Sumit; Song, Guowen

2014-10-01

335

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

336

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

337

Prediction of shell and tube thermal energy store performance  

SciTech Connect

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

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

1995-12-31

338

Flightweight radiantly and actively cooled panel: thermal and structural performance  

SciTech Connect

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/ft/sup 2/-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

339

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

340

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

341

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 highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on 8 lb/ft3 alumina-fiber-enhanced-thermal-barrier (AETB8) tiles coated with a toughened-unipiece-fibrousinsulation/ reaction-cured-glass layer (TUFI/RCG). A semi-empirical, first principles 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, Joshua E.; Bohl, William E.; Christiansen, Eric C.; Davis, Bruce A.; Foreman, Cory D.

2012-03-01

342

Hybrid Model of Existing Buildings for Transient Thermal Performance Estimation  

E-print Network

Building level energy models are important to provide accurate prediction of energy consumption for building performance diagnosis and energy efficiency assessment of retrofitting alternatives for building performance upgrading. Simplified...

Xu, X.; Wang, S.

2006-01-01

343

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

E-print Network

and reported in accordance with ASTM C- 1153; "Standard Practice for the Location of Wet Insulation in Roofing of projects and references for similar testing performed over the last ten (10) years. QUALITY CONTROL 01400

344

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

345

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

346

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

347

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

348

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

349

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

350

Thermal performance measurement of heat sinks with confined impinging jet by infrared thermography  

Microsoft Academic Search

In this paper, the thermal performance of heat sinks with confined impingement cooling is measured by infrared thermography. The effects of the impinging Reynolds number, the width and the height of the fins, the distance between the nozzle and the tip of the fins, and the type of the heat sinks on the thermal resistance are investigated. The results show

Hung-Yi Li; Shung-Ming Chao; Go-Long Tsai

2005-01-01

351

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.

352

Supersonic Energy Addition for Improving the Performance of Nuclear Thermal Rockets  

E-print Network

Supersonic Energy Addition for Improving the Performance of Nuclear Thermal Rockets V.P. Chiravalle October 14, 1999 1 #12;Nuclear thermal rockets hold much promise for application to lunar and Mars missions. Solid core nuclear rockets have been build and tested as part of the NERVA program almost thirty

Choueiri, Edgar

353

The influence of the envelope on the thermal performance of ventilated and occupied houses  

Microsoft Academic Search

The main objective of this article is to investigate the influence of the thermal properties of the envelope on the thermal performance of occupied and naturally ventilated houses. A naturally ventilated house built in Southern Brazil was modelled and calibrated in the EnergyPlus computer programme. Based on this calibrated model, a reference model for computer simulations was defined, and variations

Cláudia Donald Pereira; Enedir Ghisi

2011-01-01

354

Thermal performance of a latent heat energy storage ventilated panel for electric load management  

Microsoft Academic Search

A theoretical study was conducted to assess the thermal performance of a ventilated panel heating unit. The unit employs the latent heat energy storage method to level the electrical energy demand for domestic space heating during peak hours. A one-dimensional, semi-empirical model was developed to predict the dynamic thermal behavior of the storage unit under cyclic melting and solidification. The

A. Laouadi; M. Lacroix

1999-01-01

355

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

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

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

356

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

357

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

358

40 CFR 65.44 - External floating roof (EFR).  

Code of Federal Regulations, 2010 CFR

...shall completely cover the annular space between the external floating roof and the wall of the storage vessel in a continuous fashion. (c) EFR inspection requirements. To demonstrate compliance for an external floating roof vessel, the owner or...

2010-07-01

359

A new power module packaging technology for enhanced thermal performance  

Microsoft Academic Search

A new approach to packaging high performance power devices, Chip on Flex Power Overlay (POL) was presented. It was shown that the GE's cost effective POL power packaging technology is ideally suited for high heat flux and high performance applications. This is primarily due to the elimination of bond wires and the planar geometry which offers cooling of power devices

B. Ozmat; C. S. Korman; P. McConnelee; M. Kheraluwala; E. Delgado; R. Fillion

2000-01-01

360

Warm weather performance of a thermal envelope house in Michigan  

Microsoft Academic Search

Monitored performance results for the Park House of Howell, Michigan are presented. Warm weather performance is monitored. Configuration of the house is outlined. The average weather conditions of the seven day period in July and August of 1980 are quantified. Data are taken and correlated so as to describe the temperature gradients of the envelope. Several factors that are discussed

Rubyan

1980-01-01

361

The Envelope Thermal Test Unit (ETTU): Full Measurement of WallPerform ance  

SciTech Connect

There are many ways of calculating the dynamic thermal performance of walls and many ways of measuring the performance of walls in the laboratory, relatively few field measurements have been made of the dynamic performance of wall in situ. Measuring the thermal performance of walls in situ poses two separate problems: measuring the heat fluxes and surface temperatures of the wall, and reducing this data set into usable parameters. We have solved the first problem by developing the Envelope Thermal Test Unit (ETTU). ETTU consists of two specially constructed polystyrene blankets, 1.2m square, placed on either side of the test wall that both control and measure the surface fluxes and surface temperatures of the wall. To solve the second problem we have developed a simplified dynamic model that describes the thermal performance of a wall in terms of its steady-state conductance, a time constant, and some storage terms. We have used ETTU in the field to measure the thermal performance of walls, and have applied our simplified analysis to calculate simplified thermal parameters from this data set. In this report, we present the in-situ measurements made to date using ETTU, and the resulting model predictions. The agreement between measured and predicted surface fluxes demonstrates the ability of our test unit and analytic model to describe the dynamic performance of walls in situ.

Sonderegger, R.C.; Sherman, M.H.; Adams, J.W.

1981-10-01

362

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

363

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

364

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

365

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

366

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

E-print Network

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

Ledwith, Alison C. (Alison Catherine)

2012-01-01

367

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

PubMed Central

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

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

2009-01-01

368

SOLAR ROOF POWERS THE NJIT CAMPUS CENTER  

E-print Network

, 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 would make Leon Baptiste happy. In the summer of 2004, Baptiste installed the solar panel array

Bieber, Michael

369

Accidents due to falls from roof slabs.  

PubMed

CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%). Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%), and flying a kite was the most prevalent game (37.9%). In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places. PMID:23903263

Rudelli, Bruno Alves; Silva, Marcelo Valerio Alabarce da; Akkari, Miguel; Santili, Claudio

2013-01-01

370

Natural course of orbital roof fractures.  

PubMed

The natural course of several isolated and nonisolated orbital roof fractures is reported, by showing four cases in which a "wait and see" policy was followed. All four cases showed spontaneous repositioning and stabilizing of the fracture within less than a year. This might be explained by the equilibrium between the intraorbital and intracranial pressures. PMID:25383150

Stam, Liselotte H M; Wolvius, Eppo B; Schubert, Warren; Koudstaal, Maarten J

2014-12-01

371

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

372

Radiant Barriers in Roof Insulation Systems  

Microsoft Academic Search

A local building owner purchased a 6000 square foot metal building to be used as a retail store, parts storage, and repair shop for a large truck maintenance facility. The building manufacturer offered a radiant barrier product as an option in the roof and wall insulating systems. The building manufacturer claimed that using two inches of conventional fiberglass insulation along

Mark C. Tatum

373

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...

374

40 CFR 1037.140 - Curb weight and roof height.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

375

40 CFR 1037.140 - Curb weight and roof height.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

376

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

377

Thermal performance of a packed bed reactor for a high-temperature chemical heat pump  

Microsoft Academic Search

SUMMARY The thermal performance of a chemical heat pump that uses the reaction system of calcium oxide\\/lead oxide\\/carbon dioxide, which is developed for utilization of high-temperature heat above 8003C, is studied experimentally. The thermal performance of a packed-bed reactor of a calcium oxide\\/carbon dioxide reac- tion system, which stores and transforms a high-temperature heat source in the heat pump operation,

Yukitaka Kato; Tadashi O-shim; Yoshio Yoshizawa

2001-01-01

378

Effect of gas radiation and property variation on the performance of thermal regenerators  

E-print Network

EFFECT OF GAS RADIATION AND PROPERTY VARIATION ON THE PERFORMANCE OF THERMAL REGENERATORS A Thesis by SRINIVASA VARMA GADIRAJU Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1991 Major Subject: Mechanical Engineering EFFECT OF GAS RADIATION AND PROPERTY VARIATION ON THE PERFORMANCE OF THERMAL REGENERATORS A Thesis by SRINIVASA VARMA GADIRAJU Approved as to style and content by: W...

Gadiraju, Srinivasa Varma

2012-06-07

379

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

380

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

E-print Network

We present the thermal model of the Balloon-borne Large-Aperture Submillimeter Telescope for Polarimetry (BLASTPol). This instrument was successfully flown 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; 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, J A; Thomas, N E; Truch, M D; Tucker, C E; Tucker, G S; Ward-Thompson, D

2014-01-01

381

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

382

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

383

Performance of thermal barrier coatings in high heat flux environments  

NASA Technical Reports Server (NTRS)

Thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch. Analysis of the specimen heating rates indicates that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 C after 0.5 sec in the flame. An as-sprayed ZrO2-8 percent Y203 specimens survived 3000 of the 0.5 sec cycles with failing. Surface spalling was observed when 2.5 sec cycles were employed but this was attributed to uneven heating caused by surface roughness. This surface spalling was prevented by smoothing the surface with silicon carbide paper or by laser glazing. A coated specimen with no surface modification but which was heat treated in argon also did not surface spall. Heat treatment in air led to spalling in as early as 2 cycle from heating stresses. Failures at edges were investigated and shown to be a minor source of concern. Ceramic coatings formed from ZrO2-12 percent Y2O3 or ZrO2-20 percent Y2O3 were shown to be unsuited for use under the high heat flux conditions of this study.

Miller, R. A.; Berndt, C. C.

1984-01-01

384

Performance of thermal barrier coatings in high heat flux environments  

NASA Technical Reports Server (NTRS)

Thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch. Analysis of the specimen heating rates indicates that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 C after 0.5 sec in the flame. An as-sprayed ZrO2-8%Y2O3 specimens survived 3000 of the 0.5 sec cycles with failing. Surface spalling was observed when 2.5 sec cycles were employed but this was attributed to uneven heating caused by surface roughness. This surface spalling was prevented by smoothing the surface with silicon carbide paper or by laser glazing. A coated specimen with no surface modification but which was heat treated in argon also did not surface spall. Heat treatment in air led to spalling in as early as 2 cycle from heating stresses. Failures at edges were investigated and shown to be a minor source of concern. Ceramic coatings formed from ZrO2-12%Y2O3 or ZrO2-20%Y2O3 were shown to be unsuited for use under the high heat flux conditions of this study.

Miller, R. A.; Berndt, C. C.

1984-01-01

385

Performance of thermal barrier coatings in high heat flux environments  

NASA Technical Reports Server (NTRS)

Thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch. Analysis of the specimen heating rates indicates that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 C after 0.5 sec in the flame. An as-sprayed ZrO2-8 percent Y2O3 specimens survived 3000 of the 0.5 sec cycles with falling. Surface spalling was observed when 2.5 sec cycles were employed but this was attributed to uneven heating caused by surface roughness. This surface spalling was prevented by smoothing the surface with silicon carbide paper or by laser glazing. A coated specimen with no surface modification but which was heat treated in argon also did not surface spall. Heat treatment in air led to spalling in as early as 1 cycle from heating stresses. Failures at edges were investigated and shown to be a minor source of concern. Ceramic coatings formed from ZrO2-12 percent Y2O3 or ZrO2-2O percent Y2O3 were shown to be unsuited for use under the high heat flux conditions of this study.

Miller, R. A.; Berndt, C. C.

1984-01-01

386

PIV Applications to Thermal Performance of LPG Cooking Burners  

Microsoft Academic Search

With an increasing trend of energy consumption in domestic (1), about 59% of the total LPG was consumed by a household sector. LPG cooking burner is an important appliance for household living, which provides a good combustion with high safety. However, almost cooking burner manufactures in domestic are manufacturing their burners based on experiences rather than scientific reasons. Therefore, performance

Sumrerng Jugjai; Suvit Tia; Pumyos Vallikul; Bundit Fungtammasan

387

Range performance impact of noise for thermal system modeling  

NASA Astrophysics Data System (ADS)

This paper presents a comparison of the predictions of NVThermIP to human perception experiment results in the presence of large amounts of noise where the signal to noise ratio is around 1. First, the calculations used in the NVESD imager performance models that deal with sensor noise are described outlining a few errors that appear in the NVThermIP code. A perception experiment is designed to test the range performance predictions of NVThermIP with varying amounts of noise and varying frame rates. NVThermIP is found to overestimate the impact of noise, leading to pessimistic range performance predictions for noisy systems. The perception experiment results are used to find a best fit value of the constant ? used to relate system noise to eye noise in the NVESD models. The perception results are also fit to an alternate eye model that handles frame rates below 30Hz and smoothly approaches an accurate prediction of the performance in the presence of static noise. The predictions using the fit data show significantly less error than the predictions from the current model.

Fanning, Jonathan D.; Teaney, Brian P.; Reynolds, Joseph P.; Du Bosq, Todd W.

2009-05-01

388

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

389

Duct Thermal Performance Models for Large Commercial Buildings  

E-print Network

the accuracy or adequacy of the information in this report. THE GOVERNMENT AND THE CONTRACTOR MAKE NO EXPRESS OWNED RIGHTS OF OTHERS. NEITHER THE GOVERNMENT NOR THE CONTRACTOR SHALL BE LIABLE FOR SPECIAL debt of gratitude goes to former and current Energy Performance of Buildings staff members: Ellen

390

A venturi-shaped roof for wind-induced natural ventilation of buildings: Wind tunnel and CFD evaluation of different design configurations  

Microsoft Academic Search

Wind tunnel experiments and Computational Fluid Dynamics (CFD) are used to analyse the flow conditions in a venturi-shaped roof, with focus on the underpressure in the narrowest roof section (contraction). This underpressure can be used to partly or completely drive the natural ventilation of the building zones. The wind tunnel experiments are performed in an atmospheric boundary layer wind tunnel

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

2011-01-01

391

Use of an infrared scanner and a nuclear meter to find wet insulation in a ballasted roof  

NASA Astrophysics Data System (ADS)

An IR scanner and a nuclear moisture meter were used to survey a ballasted roof suffering chronic leaks. Infrared surveys, conducted with the ballast in place, uncovered five small wet areas. The thermal anomalies were faint and may have been missed during a routine IR roof moisture survey. Nuclear readings were taken on a 1.5-m (5-ft) grid. HIgh nuclear readings were obtained at the one grid point that fell within one of the five wet areas detected during the IR survey. The other four wet areas were missed. However, the nuclear meter found an additional nine small wet areas that the IR scanner missed. All but one of these areas contained wet urethane insulation directly below the membrane. In three other areas of the roof, nuclear readings were higher than those over the rest of the roof. Core samples verified that the perlite insulation at the base of the roof was wet in these areas, two of which were small but one was 12 X 12 m (40 X 40 ft) when squared off. This `deep' moisture was not detected thermographically. On this roof IR and nuclear surveys both provided valuable information but each missed a portion of the problem. When used in combination, their strengths were complementary.

Tobiasson, Wayne; Greatorex, Alan R.

1994-03-01

392

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

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

393

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

394

Thermal performance of a new solar air heater  

SciTech Connect

A solar air heater, part of a food drying system using solar energy as a renewable energy source for heat, was developed and tested for several agricultural products (i.e., sultana grapes, green beans, sweet peppers, chili peppers). Drying processes were conducted in the chamber with forced natural air heated partly by solar energy. Solar air heater performances were discussed along with estimates of energy efficiency of the system. The obtained results indicate that the present system is efficiency and effective.

Tiris, C.; Ozbalta, N. [Ege Univ., Izmir (Turkey). Solar Energy Institute] [Ege Univ., Izmir (Turkey). Solar Energy Institute; Tiris, M.; Dincer, I. [TUBITAK-Marmara Research Center, Kocaeli (Turkey)] [TUBITAK-Marmara Research Center, Kocaeli (Turkey)

1995-05-01

395

The growth and survival of plants in urban green roofs in a dry climate.  

PubMed

Green roofs as one of the components of water-sensitive urban design have become widely used in recent years. This paper describes performance monitoring of four prototype-scale experimental green roofs in a northern suburb of Adelaide, South Australia, undertaken over a 1-year period. Four species of indigenous Australian ground cover and grass species comprising Carpobrotus rossii, Lomandra longifolia 'Tanika,' Dianella caerula 'Breeze' and Myoporum parvifolium were planted in extensive and intensive green roof configurations using two different growing media. The first medium consisted of crushed brick, scoria, coir fibre and composted organics while the second comprised scoria, composted pine bark and hydro-cell flakes. Plant growth indices including vertical and horizontal growth rate, leaf succulence, shoot and root biomasses, water use efficiency and irrigation regimes were studied during a 12-month period. The results showed that the succulent species, C. rossii, can best tolerate the hot, dry summer conditions of South Australia, and this species showed a 100% survival rate and had the maximum horizontal growth rate, leaf succulence, shoot biomass and water use efficiency. All of the plants in the intensive green roofs with the crushed brick mix media survived during the term of this study. It was shown that stormwater can be used as a source of irrigation water for green roofs during 8 months of the year in Adelaide. However, supplementary irrigation is required for some of the plants over a full annual cycle. PMID:24468503

Razzaghmanesh, M; Beecham, S; Kazemi, F

2014-04-01

396

Optimum performance of a regenerative Brayton thermal cycle  

NASA Astrophysics Data System (ADS)

The optimum performance of a regenerative Brayton cycle was analyzed. The model includes external and internal irreversibilities coming from four main sources: coupling to external heat reservoirs, turbine and compressor nonisentropic processes, pressure losses in the heater and the cooler, and the regenerator. In terms of the parameters accounting for each type of irreversibility, explicit numerical results are presented for the maximum efficiency, maximum power output, efficiency at maximum power output, power output at maximum efficiency, as well as for the pressure ratios required for maximum efficiency and maximum power. This analysis could provide a general theoretical tool for the optimal design and operation of real regenerative gas turbine power plants.

Roco, J. M. M.; Velasco, S.; Medina, A.; Hernández, A. Calvo

1997-09-01

397

Evaluation of annual performance of 2-tank and thermocline thermal storage for trough plants  

Microsoft Academic Search

A study was performed to compare the annual performance of 50 MW{sub e} Andasol-like trough plants that employ either a 2-tank or a thermocline-type molten-salt thermal storage system. trnsys software was used to create the plant models and to perform the annual simulations. The annual performance of each plant was found to be nearly identical in the base-case comparison. The

Kolb; Gregory J

2010-01-01

398

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 use of single-family residences with heating, ventilating, and air-conditioning (HVAC) systems in their basements. In this paper, results from a four-house field study in Maryland and computer simulations are used to examine the potential for improvement in efficiency of air distribution systems in such houses. The field study results are focused on characterizing the airflow performance of the four duct systems and the physical characteristics of the houses and duct systems. Simulations of a basement house, the characteristics of which were loosely based on those from the measured houses, were performed to investigate the energy-saving potential for basement houses. The simulations estimate that a 9% reduction in space-conditioning energy use is obtained by sealing 80% of the leaks and adding insulation with an R-value of 0.88 C{center_dot}m{sup 2}/W (5 F{center_dot}ft{sup 2}{center_dot}h/Btu) to uninsulated sheet-metal ducts that are accessible from the basement. Simulations were also run with all ducts insulated to 17.6 C{center_dot}m{sup 2}/W and with no duct leakage, for which the savings in energy use was increased to 14% of the original consumption.

Treidler, B.; Modera, M.P. [Lawrence Berkeley Lab., CA (United States). Energy and Environment Div.

1996-11-01

399

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

400

Establishing green roof infrastructure through environmental policy instruments.  

PubMed

Traditional construction practices provide little opportunity for environmental remediation to occur in urban areas. As concerns for environmental improvement in urban areas become more prevalent, innovative practices which create ecosystem services and ecologically functional land cover in cities will be in higher demand. Green roofs are a prime example of one of these practices. The past decade has seen the North American green roof industry rapidly expand through international green roof conferences, demonstration sites, case studies, and scientific research. This study evaluates existing international and North American green roof policies at the federal, municipal, and community levels. Green roof policies fall into a number of general categories, including direct and indirect regulation, direct and indirect financial incentives, and funding of demonstration or research projects. Advantages and disadvantages of each category are discussed. Salient features and a list of prompting standards common to successfully implemented green roof strategies are then distilled from these existing policies. By combining these features with data collected from an experimental green roof site in Athens, Georgia, the planning and regulatory framework for widespread green roof infrastructure can be developed. The authors propose policy instruments be multi-faceted and spatially focused, and also propose the following recommendations: (1) Identification of green roof overlay zones with specifications for green roofs built in these zones. This spatial analysis is important for prioritizing areas of the jurisdiction where green roofs will most efficiently function; (2) Offer financial incentives in the form of density credits and stormwater utility fee credits to help overcome the barriers to entry of the new technology; (3) Construct demonstration projects and institutionalize a commitment greening roofs on publicly-owned buildings as an effective way of establishing an educated roofing industry and experienced installers for future green roof construction. PMID:18389306

Carter, Timothy; Fowler, Laurie

2008-07-01

401

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

402

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

403

Thermal performance of MSFC hot air collectors under natural and simulated conditions  

NASA Technical Reports Server (NTRS)

The procedures used and the results obtained from an evaluation test program conducted to determine the thermal performance and structural characteristics of selected MSFC--designed hot air collectors under both real and simulated environmental conditions are described. Five collectors were tested in the three phased program. A series of outdoor tests were conducted to determine stagnation temperatures on a typical bright day and to determine each collector's ability to withstand these temperatures. Two of the collectors experienced structural deformation sufficient to eliminate them from the remainder of the test program. A series of outdoor tests to evaluate the thermal performance of collector S/N 10 under certain test conditions were performed followed by a series of indoor tests to evaluate the thermal performance of the collector under closely controlled simulated conditions.

Shih, K., Sr.

1977-01-01

404

Largo hot water system long range thermal performance test report, addendum  

NASA Technical Reports Server (NTRS)

The test procedure used and the test results obtained during the long range thermal performance tests of the LARGO Solar Hot Water System under natural environmental conditions are presented. Objectives of these tests were to determine the amount of energy collected, the amount of power required for system operation, system efficiency, temperature distribution, and system performance degradation.

1978-01-01

405

Thermal performance of the Peterson Residence: a double shell envelope house  

Microsoft Academic Search

The Peterson Residence is a double shell envelope house located near Baltimore, MD and designed for the temperature climate of the Middle Atlantic Region. A multipoint strip chart recorder was installed in February 1981 to continuously monitor the thermal performance throughout the year. This report is based upon the preliminary data collected during March 1981. Performance results are presented and

Kunz

1981-01-01

406

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

407

Visualizing the thermal performance of heat pipes with thermochromic liquid crystals  

NASA Technical Reports Server (NTRS)

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 state isotherms during low temperature operation. The start-up and operational behaviors of the heat pipe as well as the presence of non-condensible gases can be visually identified through a spectrum of color changes. A brief video demonstration illustrating heat pipe thermal performance characteristics has been developed and illustrates the utility of TLCs for visualizing thermal behavior.

Gunnerson, Fred S.; Thorncroft, Glen E.

1991-01-01

408

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

409

Comparison of theory and experiment for photovoltaic/thermal collector performance  

SciTech Connect

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

Hendrie, S.D.

1980-01-01

410

The selection and performance of thermal sprayed abradable seal coatings for gas turbine engines  

SciTech Connect

Criteria used in designing thermal sprayed abradable seal coatings for gas turbine engines are discussed. These include the conditions of being readily abradable and yet being resistable to particle impact erosion from engine-ingested abrasive dust at high gas velocities. Other important criteria include temperature stability, inertness, and consistency. The paper describes the classes of abradable seal materials; the characterization of thermal sprayed abradables; the current coating materials' temperature, erosion, and abradability performance; and current research in thermal sprayed abradable coating materials. 5 refs.

Novinski, E.R.

1989-01-01

411

Thermal performance of an Ekose'a-design double-envelope house  

Microsoft Academic Search

To assess the energy effectiveness of a double-envelope house, an Ekose'a-design house has been monitored. Thermal characteristics of the house and the amount of auxiliary backup heat required in the heating season are assessed. House thermal behavior during representative days in the swing or cooling season is determined, and integrated or averaged monthly results homogeneous patterns of daily performance and

H. T. Ghaffari; R. F. Jones

1981-01-01

412

House thermal envelope conservation optimization with respect to performance\\/economics  

Microsoft Academic Search

The performance and economics of various residential thermal envelope energy conserving features are analyzed employing computer methods. Variations in external wall construction such as 2 x 4, 2 x 6, double-wall, and strapped-wall are treated. Variations in ceiling insulation, floor insulation, air\\/vapor sealing, number of window glazings, and window orientation are included. The house thermal envelopes vary from present average

Zehr

1984-01-01

413

Effects of airflow infiltration on the thermal performance of internally insulated ducts  

Microsoft Academic Search

Air flowing through a supply duct infiltrates perviously faced, porous, internal duct insulation, degrading its thermal performance. Encapsulating the insulation's air-facing surface with an impervious barrier prevents infiltration, increasing the capacity of the conditioned supply air to heat or cool the space to which it is delivered.This study determined the air-speed dependence of the thermal conductivity of fiberglass insulation by

Ronnen Levinson; Wm. Woody Delp; Darryl Dickerhoff; Mark Modera

2000-01-01

414

Study on the cell size effect of steady state thermal performance of metallic honeycomb sandwich panels  

NASA Astrophysics Data System (ADS)

In this paper, numerical study is performed to reveal the influences of the cell size on the steady state thermal performance of hexagonal metallic honeycomb sandwich panel, by using the semi-empirical Swann and Pittman formula and the Finite Element Method (FEM), respectively. Based on the same material volume of honeycomb core, two types of hexagonal honeycomb core, i.e., size variation of core cell with a constant core height and height variation of core with a constant side length of hexagonal cell, are considered to establish the panel's thermal analysis model, which including the conduction and radiation coupling. Comparisons between the temperature distribution results from both methods show that FEM can reveal the size effect of the honeycomb cell on the thermal performances of sandwich panel while the Swann and Pittman formula can not. At the same time, numerical results show that for the core with constant height, the panel thermal performance analyzed by FEM has a tendency of being close to the results obtained from Swann and Pittman formula as the core cell size decreases; whereas, if the hexagonal cell with constant side length is concerned, the greater the core height, the worse the thermal conductive performance of sandwich panel. Besides, analyses based on both methods also show that the temperature distribution of the lower surface of panel becomes gradually uniform when the wall thickness of hexagonal cell decreases.

Lai, Yu-dong; Sun, Shi-ping

2011-11-01

415

Study on the cell size effect of steady state thermal performance of metallic honeycomb sandwich panels  

NASA Astrophysics Data System (ADS)

In this paper, numerical study is performed to reveal the influences of the cell size on the steady state thermal performance of hexagonal metallic honeycomb sandwich panel, by using the semi-empirical Swann and Pittman formula and the Finite Element Method (FEM), respectively. Based on the same material volume of honeycomb core, two types of hexagonal honeycomb core, i.e., size variation of core cell with a constant core height and height variation of core with a constant side length of hexagonal cell, are considered to establish the panel's thermal analysis model, which including the conduction and radiation coupling. Comparisons between the temperature distribution results from both methods show that FEM can reveal the size effect of the honeycomb cell on the thermal performances of sandwich panel while the Swann and Pittman formula can not. At the same time, numerical results show that for the core with constant height, the panel thermal performance analyzed by FEM has a tendency of being close to the results obtained from Swann and Pittman formula as the core cell size decreases; whereas, if the hexagonal cell with constant side length is concerned, the greater the core height, the worse the thermal conductive performance of sandwich panel. Besides, analyses based on both methods also show that the temperature distribution of the lower surface of panel becomes gradually uniform when the wall thickness of hexagonal cell decreases.

Lai, Yu-dong; Sun, Shi-ping

2012-04-01

416

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

417

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...

418

Condensation, heat transfer and ventilation processes in flat timber-frame cold roofs  

Microsoft Academic Search

An experimental study of the heat and moisture transfer processes in an insulated flat timber cold roof, 4.4 m long x 2 m wide, has been carried out under controlled steady state winter conditions and wind speeds up to 5 m s-1. The experiments were performed with intact, perforated and absent vapour barriers on the ceiling. The cavity between the

A. Simpson; G. Castles; D. E. OConnor

1992-01-01

419

The role of adaptive thermal comfort in the prediction of the thermal performance of a modern mixed-mode office building in the UK under climate change  

Microsoft Academic Search

Climate change is becoming a serious issue for the construction industry, since the time scales at which climate change takes place can be expected to show a true impact on the thermal performance of buildings and HVAC systems. In predicting this future building performance by means of building simulation, the underlying assumptions regarding thermal comfort conditions and the related heating,

Pieter de Wilde; Wei Tian

2010-01-01

420

Demonstration of energy savings of cool roofs. Executive summary  

SciTech Connect

The use of dark roofs affects cooling and heating energy use in buildings and the urban climate. At the building scale, dark roofs are heated by the summer sun and thus raise the summertime air-conditioning (a/c) demand. For highly-absorptive (low-albedo) roofs the difference between the surface and ambient air temperatures may be as high as 90 F on a summer afternoon. While for less absorptive (high-albedo) surfaces with similar insulative properties, such as roofs covered with a white coating, the difference is only about 20 F. For this reason, cool roofs (which absorb little insolation) can be effective in reducing cooling energy use. Earlier studies have suggested that cool roofs incur no additional cost if color changes are incorporated into routine re-roofing and re-surfacing schedules. There is a sizable body of measured data (primarily collected for residential sector) documenting energy-saving effects of cool roofs as shown. Both measured data and simulations clearly demonstrate that increasing the albedo of roofs is an attractive (and cost-effective) way of reducing the net radiative heat gains through the roof and hence, reducing building cooling loads. To change the albedo, the rooftops of buildings may be painted with reflective coatings or covered with a new light-colored material. Since most roofs have regular maintenance schedules or need to be re-roofed or re-coated periodically, the change of the albedo should be done then. In that case, the cost would be limited to the incremental cost associated with the high-albedo material. In buildings and climates with significant air-conditioning use, increasing the albedo of roofs will reduce energy use and produce a stream of savings immediately.

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

421

Effect of nanoparticles in nanofluid on thermal performance in a miniature thermosyphon  

Microsoft Academic Search

An experiment was performed to investigate the effect of nanoparticles in the nanofluid on the thermal performance in a miniature thermosyphon. The nanofluids consisted of de-ionized water and CuO nanoparticles having an average size of 30 nm. The experimental results show that the water-CuO nanofluids can greatly enhance the boiling heat transfer performance of the evaporator in thermosyphon compared with

Zhen Hua Liu; Xue Fei Yang; Guang Liang Guo

2007-01-01

422

Performance study of underground thermal storage in a solar-ground coupled heat pump system for residential buildings  

Microsoft Academic Search

This paper is performed to analyze the performance of underground thermal storage in a solar-ground coupled heat pump system (SGCHPS) for residential building. Based on the experimental results, the system performance during a longer period is simulated by the unit modeling, and its parametric effects are discussed. The results show that the performance of underground thermal storage of SGCHPS depends

Huajun Wang; Chengying Qi

2008-01-01

423

Experimental Investigation of Thermal Performance in a Concentric-Tube Heat Exchanger with Wavy Inner Pipe  

NASA Astrophysics Data System (ADS)

In this article, the heat transfer, friction factor, and thermal performance factor characteristics of a concentric-tube heat exchanger are examined experimentally. A wavy inner pipe is mounted in the tube with the purpose of generating swirl flow that would help to increase the heat transfer rate of the tube. The examination is performed for a Reynolds number ranging from 2700 to 8800. An empirical correlation is also formulated to match with experimental data of the Nusselt number using the Wilson plot method. In addition, to obtain the real benefits in using the swirl generator at a constant pumping power, the thermal enhancement factor is also determined. Over the range considered, the increases in the Nusselt number, friction factor, and thermal performance factor are found to be, respectively, about 113 %, 81 %, and 196 % higher than those obtained from a smooth-surface inner pipe.

Çakmak, Gül?ah; Yücel, H. Lütfi; Argunhan, Zeki; Y?ld?z, Cengiz

2012-06-01

424

5cm, no iron SSC dipole 12m model cryostat thermal performance  

NASA Astrophysics Data System (ADS)

A 12 m long model of a 5 cm costheta dipole cryostat has been constructed and its thermal performance measured. The model utilized heat intercepted fiberglass reinforced plastic posts to support the 12 m long, 4.5 K cold mass and the 10 and 80 K thermal shields. A superinsulation blanket system utilizing aluminized polyester with fiberglass mat spacing material was developed and installed on the 10 and 80 K thermal shields. The heat gain to 4.5, 10 and 80 K was measured. We have compared the results with the analytical predicted performance and it shows good agreement. The performance of the multilayer insulation system has been measured under several different system conditions and the results are reported.

Powers, R. J.; Gonczy, J. D.; Otavka, J.; Niemann, R. C.; Szymulanski, A.; Tague, J. L.

1985-09-01

425

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

Microsoft Academic Search

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

Hashem Akbari; Ronnen Levinson; Arthur Rosenfeld; Matthew Elliot

2009-01-01

426

Leaf and Life History Traits Predict Plant Growth in a Green Roof Ecosystem  

PubMed Central

Green roof ecosystems are constructed to provide services such as stormwater retention and urban temperature reductions. Green roofs with shallow growing media represent stressful conditions for plant survival, thus plants that survive and grow are important for maximizing economic and ecological benefits. While field trials are essential for selecting appropriate green roof plants, we wanted to determine whether plant leaf traits could predict changes in abundance (growth) to provide a more general framework for plant selection. We quantified leaf traits and derived life-history traits (Grime’s C-S-R strategies) for 13 species used in a four-year green roof experiment involving five plant life forms. Changes in canopy density in monocultures and mixtures containing one to five life forms were determined and related to plant traits using multiple regression. We expected traits related to stress-tolerance would characterize the species that best grew in this relatively harsh setting. While all species survived to the end of the experiment, canopy species diversity in mixture treatments was usually much lower than originally planted. Most species grew slower in mixture compared to monoculture, suggesting that interspecific competition reduced canopy diversity. Species dominant in mixture treatments tended to be fast-growing ruderals and included both native and non-native species. Specific leaf area was a consistently strong predictor of final biomass and the change in abundance in both monoculture and mixture treatments. Some species in contrasting life-form groups showed compensatory dynamics, suggesting that life-form mixtures can maximize resilience of cover and biomass in the face of environmental fluctuations. This study confirms that plant traits can be used to predict growth performance in green roof ecosystems. While rapid canopy growth is desirable for green roofs, maintenance of species diversity may require engineering of conditions that favor less aggressive species. PMID:24978031

Lundholm, Jeremy; Heim, Amy; Tran, Stephanie; Smith, Tyler

2014-01-01

427

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

428

Predicting and evaluating the performance of ice-harvesting thermal energy storage systems  

SciTech Connect

Ice-harvesting thermal storage systems have been applied to a large number of cool thermal storage systems. Field verification of the performance of these systems is difficult because direct methods of weighing the ice are impractical in all but the smallest systems. This paper discusses the operating characteristics of ice-harvesting equipment using heat-initiated defrost cycles, the process of ice formation, a simplified model for predicting ice-making performance, and defrost energy requirements. The result of this analysis is the prediction of the net rated ice-making capacity of the system in the ice-making mode.

Knebel, D.E. [Univ. of Wisconsin, Madison, WI (United States). Thermal Storage Applications Research Center

1995-08-01

429

Analyses of flight model spacecraft performance during thermal-vacuum tests  

NASA Technical Reports Server (NTRS)

Malfunction data from the thermal-vacuum tests of 39 flight-model spacecraft have been analyzed. The results are interpreted in terms of the test variables and the spacecraft performance. The malfunction data are correlated with the test time as a single variable, and also with the composite variable of time plus temperature. The improvement in spacecraft performance is examined by means of malfunction rates, malfunctions per spacecraft, and the probability of no failure related to test time. The minimum thermal-vacuum test profile required for Goddard Space Flight Center spacecraft is verified, and the probability of a defect remaining undetected is estimated.

Timmins, A. R.; Heuser, R. E.; Strain, J. C.

1973-01-01

430

Analyses of flight model spacecraft performance during thermal-vacuum tests  

NASA Technical Reports Server (NTRS)

Malfunction data from the thermal-vacuum tests of 39 flight-model spacecraft were analyzed. The results are interpreted in terms of the test variables, and in terms of the spacecraft performance. The malfunction data are correlated with the test time as a single variable, and also with the composite variable of time plus temperature. The improvement in spacecraft performance is examined by means of malfunction rates, malfunctions per spacecraft, and the probability of no failure related to test time. The minimum thermal-vacuum test profile required for Goddard Space Flight Center spacecraft is verified, and the probability of a defect remaining undetected is estimated.

Timmins, A. R.; Heuser, R. E.; Strain, J. C.

1972-01-01

431

Effect of water turbidity on thermal performance of a salt-gradient solar pond  

SciTech Connect

The effect of water turbidity on the thermal performance of a salt-gradient solar pond is studied using a one-dimensional theoretical model. The theoretical model uses an empirical correlation that includes the effect of water turbidity on solar radiation penetration in water. The correlation is based on a uniform turbidity distribution in water; however, the correlation is extended to include a non-uniform turbidity distribution with respect to depth of water. The results indicate that water clarity plays a significant role on thermal performance for salt gradient solar ponds. 24 refs., 11 figs., 1 tab.

Wang, J.; Seyed-Yagoobi, J. [Texas A& M Univ., College Station, TX (United States)] [Texas A& M Univ., College Station, TX (United States)

1995-05-01

432

Influence of surface treatment of components on thermal radiation performance in infrared optical systems  

NASA Astrophysics Data System (ADS)

The existence of self-generated thermal radiation in infrared optical systems exhibits a great impact to the extraction of target signal and further degrades the signal-to-noise ratio (SNR), thus making the self-generated thermal radiation one of the important factors affecting the detective property. In this paper, a refraction-reflection optical system has been taken as an example and the three-dimensional simulation model has been built up using the ASAP optical analysis software. On this basis, the influence of the surface roughness, the level of the optics contaminated by the particles with the uniform and non-uniform distributions, the treatment of the mechanical surface (such as blacking, polishing, roughening) on the self-generated thermal radiation have been focused on discussion. Moreover, the thermal radiation of the system has been evaluated by the effective emissivity. The results indicate that the effective emissivity varies with different surface treatment. The self-generated thermal radiation is more and more serious with the increasing of the effective emissivity, resulting in great difficulty in obtaining and analyzing the target signal. It follows that the surface treatment of components exhibits a significant effect on the stray radiation performance in infrared optical systems. Consequently, appropriate treatments should be taken to diminish the self-generated thermal radiation in order to meet the requirements of the stray radiation performance in practical applications.

Luo, Wen-fei; Wu, Jian-peng; Peng, Jia-qi; Zhang, Bin

2014-09-01

433

Green Roofs: Federal Energy Management Program (FEMP) Federal Technology Alert  

SciTech Connect

In a ''green roof,'' a layer of vegetation (e.g., a roof garden) covers the surface of a roof to provide shade, cooler indoor and outdoor temperatures, and effective storm-water management to reduce runoff. The main components are waterproofing, soil, and plants. There are two basic kinds: intensive and extensive. An intensive green roof often features large shrubs and trees, and it can be expensive to install and maintain. An extensive green roof features shallow soil and low-growing, horizontally spreading plants that can thrive in the alpine conditions of many rooftops. These plants do not require a lot of water or soil, and they can tolerate a significant amount of exposure to the sun and wind. This Federal Technology Alert focuses on the benefits, design, and implementation of extensive green roofs and includes criteria for their use on federal facilities.

Scholz-Barth, K.; Tanner, S.

2004-09-01

434

Relationship of roof rat population indices with damage to sugarcane  

USGS Publications Warehouse

Roof rats (Rattus rattus) cause substantial damage to sugarcane in South Florida (Samol 1972; Lefebvre et al. 1978, 1985). Accurate estimates of roof rat populations in sugarcane fields would be useful for determining when to to treat a field to control roof rats and for assessing the efficacy of control. However, previous studies have indicated that roof rats exhibit trap shyness, which makes capture-recapture population estimates difficult (Lefebvre et al. 1978, 1985; Holler et al., 1981). Until trapping methods are sufficiently improved to allow accurate population estimates, indices of population size that relate to damage need to be developed. The objectives of our study were to examine the relationship of several indices of roof rat populations to the percentage of sugarcane stalks damaged at harvest; to determine which population index would be most useful for sugarcane growers; and to report on a test of several types of live traps for roof rats.

Lefebvre, Lynn W.; Engeman, Richard M.; Decker, David G.; Holler, Nicholas R.

1989-01-01

435

Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services  

NSDL National Science Digital Library

This peer-reviewed article from the November 2007 issue of BioScience evaluates the environmental benefits of green roof construction.Green roofs (roofs with a vegetated surface and substrate) provide ecosystem services in urban areas, including improved storm-water management, better regulation of building temperatures, reduced urban heat-island effects, and increased urban wildlife habitat. This article reviews the evidence for these benefits and examines the biotic and abiotic components that contribute to overall ecosystem services. We emphasize the potential for improving green-roof function by understanding the interactions between its ecosystem elements, especially the relationships among growing media, soil biota, and vegetation, and the interactions between community structure and ecosystem functioning. Further research into green-roof technology should assess the efficacy of green roofs compared to other technologies with similar ends, and ultimately focus on estimates of aggregate benefits at landscape scales and on more holistic cost-benefit analyses.

ERICA OBERNDORFER (Saint Mary's University, Halifax, Nova Scotia, Canada;Biology); JEREMY LUNDHOLM (Saint Mary's University, Halifax, Nova Scotia, Canada;Biology); Brad Bass (University of Toronto's Centre for Environment;); Reid Coffman (University of Oklahoma in Norman;Division of Landscape Architecture); Hitshi Doshi (Ryerson University;Architectural Science); Nigel Dunnett (University of Sheffield;Landscape)

2007-12-26

436

Large-scale changes in thermal sensitivity of flight performance during adult maturation in a dragonfly  

PubMed

Newly emerged adult dragonflies are physiologically immature in a number of ways, including the mass, ultrastructure and biochemistry of their flight muscles. In Libellula pulchella dragonflies, adult maturation of flight muscle is accompanied by striking changes in thermal physiology. Vertical force production during fixed flight attempts in newly emerged adults (tenerals) shows a broad plateau of near-peak performance, first attained at cool thoracic temperatures (typically 28­34 °C) and maintained up to thoracic temperatures of 40­45 °C [mean optimal thoracic temperature (OTT)=34.6 °C; mean upper lethal temperature (ULT)=45.3 °C]. In contrast, fully mature adults show narrow thermal sensitivity curves, wherein peak performance is approached only within a few degrees of the thermal optimum, which invariably occurs at hot thoracic temperatures (38­50 °C; mean OTT=43.5 °C; mean ULT=48.6 °C). These changes in the shape and position of thermal performance curves are compared with predictions from hypotheses for the evolution of thermal sensitivity. PMID:9320006

Marden

1995-01-01

437

Demonstration of energy savings of cool roofs. Executive summary  

Microsoft Academic Search

The use of dark roofs affects cooling and heating energy use in buildings and the urban climate. At the building scale, dark roofs are heated by the summer sun and thus raise the summertime air-conditioning (a\\/c) demand. For highly-absorptive (low-albedo) roofs the difference between the surface and ambient air temperatures may be as high as 90 F on a summer

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

1998-01-01

438

Cool Roofs to Save Money and Delay Global Warming  

Microsoft Academic Search

White roofs, and now cool-colored roofs, with a high reflectivity or `albedo' have a long history (best known around the Mediterranean) of keeping buildings and cities cool. In modern times, cool roofs have been shown to reduce air conditioning (a-c) demand and slow the formation of ozone (smog). Studies establishing a typical 10% reduction in a-c demand and electricity savings

Arthur Rosenfeld

2006-01-01

439

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

E-print Network

green roof system, with an 11.6 cm deep substrate. Twelve trays were assembled and planted on April 3, 2009. Three succulent species of plants were investigated including Talinum calycinum, Delosperma cooperi and Sedum kamtschaticum. Nine individual... and periodically irrigated through August 2009. The plants became established during a year marked by extreme drought, however, not all species performed equally. During the drought, Talinum calycinum performed best, Delosperma cooperi performed well with only...

Dvorak, B.

440

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

441

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

NASA Technical Reports Server (NTRS)

A comprehensive characterization program is underway at JPL to generate test data on long-life, miniature Stirling-cycle cryocoolers for space application. The key focus of this paper is on the thermal performance of the British Aerospace (BAe) 80 K split-Stirling-cycle cryocooler as measured in a unique calorimetric thermal-vacuum test chamber that accurately simulates the heat-transfer interfaces of space. Two separate cooling fluid loops provide precise individual control of the compressor and displacer heatsink temperatures. In addition, heatflow transducers enable calorimetric measurements of the heat rejected separately by the compressor and displacer. Cooler thermal performance has been mapped for coldtip temperatures ranging from below 45 K to above 150 K, for heatsink temperatures ranging from 280 K to 320 K, and for a wide variety of operational variables including compressor-displacer phase, compressor-displacer stroke, drive frequency, and piston-displacer dc offset.

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

1992-01-01

442

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

443

Green Roofs in the New York Metropolitan Region  

E-print Network

.....................................................................................1 Cynthia Rosenzweig, Stuart Gaffin, and Lily Parshall I. Data Analysis and Modeling Energy Balance Potential Impact of Green Roofs on the Urban Heat Island Effect

444

15. INTERIOR, DETAIL OF SKYLIGHT AT ROOF PEAK, ORIGINAL BUILDING ...  

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

15. INTERIOR, DETAIL OF SKYLIGHT AT ROOF PEAK, ORIGINAL BUILDING - Newport News & Old Point Railway & Electric Company, Trolley Barn & Administration Building, 3400 Victoria Boulevard, Hampton, Hampton, VA

445

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

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The effect of colour on the thermal performance of building integrated solar collectors  

Microsoft Academic Search

The use of solar collectors with coloured absorbers for water heating is an a