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Low density foams for vacuum insulation

Description: An investigation to find an open cell foam polymer for vacuum insulation has shown an epoxy-modified isocyanurate foam to be superior to urea/formaldehyde foams. Though improved during the study, the urea/formaldehyde foams still had problems of being too friable, dimensionally unstable, and possessed of the odor of unreacted formaldehyde. Thermogravimetric and thermomechanical analyses showed the epoxy-modified isocyanurate foam to be more thermally and dimensionally stable than the urea/ formaldehyde foams. (auth)
Date: September 1, 1973
Creator: Richardson, W.E.
Partner: UNT Libraries Government Documents Department

Evaluation of Aerogel Materials for High-Temperature Batteries

Description: Siiica aerogels have 1/3 the thermal conductivity of the best commercial composite insulations, or ~13 mW/m-K at 25°C. However, aerogels are transparent in the near IR region of 4-7 µm, which is where the radiation peak from a thermal-battery stack occurs. Titania and carbon- black powders were examined as thermal opacifiers, to reduce radiation at temperatures between 300°C and 600°C, which spans the range of operating temperature for most thermal batteries. The effectiveness of the various opacifiers depended on the loading, with the best overall results being obtained using aerogels filled with carbon black. Fabrication and strength issues still remain, however.
Date: May 4, 1999
Creator: Ashley, Carol S.; Guidotti, Ronald A.; Reed, Scott T. & Reinhardt, Frederick W.
Partner: UNT Libraries Government Documents Department

Radiation and gas conduction heat transport across a helium dewar multilayer insulation system

Description: This report describes a method for calculating mixed heat transfer through the multilayer insulation used to insulate a 4 K liquid helium cryostat. The method described here permits one to estimate the insulation potential for a multilayer insulation system from first principles. The heat transfer regimes included are: radiation, conduction by free molecule gas conduction, and conduction through continuum gas conduction. Heat transfer in the transition region between the two gas conduction regimes is also included.
Date: October 10, 1994
Creator: Green, M.A.
Partner: UNT Libraries Government Documents Department

Characterization of vacuum-multifoil insulation for long-life thermal batteries

Description: The use of vacuum multifoil (VMF) container for thermal insulation in long-life thermal batteries was investigated in a proof-of-concept demonstration. An InvenTek-designed VMF container 4.9 inches in diameter by 10 inches long was used with an internally heated aluminum block, to simulate a thermal-battery stack. The block was heated to 525 C or 600 C and allowed to cool while monitoring the temperature of the block and the external case at three locations with time. The data indicate that it should be possible to build an equivalent-sized thermal battery that should last up to six hours, which would meet the requirements for a long-life sonobuoy application.
Date: April 17, 2000
Partner: UNT Libraries Government Documents Department

Development of a system of innovative insulated building blocks under energy related inventions grant. Quarterly progress report, ThermaLock Products, Inc., April 1, 1993--June 30, 1993

Description: Progress is briefly presented on the research pertaining to insulated building blocks. Areas covered include development of a stuffing machine, fabrication, sound tests, and earthquake test design.
Date: July 6, 1993
Partner: UNT Libraries Government Documents Department

Development of high performance refractory fibers with enhanced insulating properties and longer service lifetimes: Phase 2, Improved refractory fiber and industrial benefit development. Final report

Description: This is Phase II of a three-phase study for the development of high performance refractory fibers with enhanced insulating properties and longer service lifetimes, for use in the aluminum, glass, cement, and iron and steel industries. Fiberization of 24 out of 25 compositions in the Al{sub 2}O{sub 3}-Si0{sub 2}-Zr0{sub 2} system were achieved. These 24 and three existing fiber compositions were evaluated: The shrinkage and the crystalline and vitreous phases were determined vs heat treatment time and temperature. Four theoretical models were developed: Shrinkage, devitrification kinetics, density change, and fiberization. Although some of the fibers formed during Phase II had properties as good as the reference ASZ fiber, no fiber had a significantly improved performance. This work, although not entirely successful, did produce significant benefits to refractory insulating fiber manufacturers and users: Mechanisms of both linear and thickness shrinkage for vitreous refractory fibers were determined, devitrification kinetics were quantified and used in models to predict shrinkage during service, and the mechanism of fiber formation in the melt spinning process was studied.
Date: May 1, 1995
Creator: Cai, Yifang; Curtis, J.M.; DePoorter, G.L.; Martin, P.C. & Munoz, D.R.
Partner: UNT Libraries Government Documents Department

Thermal behavior of mixtures of perlite and phase change material in a simulated climate

Description: A new concept for use of phase change material (PCM) in building envelopes has been investigated. The concept is called a RCR system in analogy to an electrical circuit with a capacitor between two resistors. Here, the thermal capacitance of the PCM is sandwiched between the thermal resistance of conventional insulation. The PCM used was hydrated calcium chloride dispersed in perlite and contained in watertight test cells. One cell had a PCM/perlite ratio of 2:1 by weight; the other had a 6:1 mixture. Extruded polystyrene (XPS) was the insulation below and above the PCM. Heat-flux transducers on the top and bottom of each cell as well as thermocouples from the top to the bottom of each cell allowed them to follow closely the progression of freezing and melting in the PCM as the authors subjected the cells to both steady and diurnally varying simulated outside temperatures. Computer modeling with a transient heat conduction program was successful in proving that they understood the relevant energy transfer mechanisms and thermophysical properties. For the diurnal cycles, with twice the amount of XPS below as above the PCM, much of the energy stored during daytime by melting PCM flowed to the outside at night when it froze again. Comparisons were made to the behavior of conventional insulation. With PCM, the total daily energy flow into the conditioned space below the test cells was lower and the peak flow rate was delayed in time and decreased in magnitude.
Date: February 1997
Creator: Petrie, T. W.; Childs, P. W.; Christian, J. E.; Childs, K. W. & Shramo, D. J.
Partner: UNT Libraries Government Documents Department

Exterior exposed ductwork: Delivery effectiveness and efficiency

Description: Most of California`s light commercial buildings use air transport through ductwork for thermal distribution. The same air distribution systems are often used to provide both thermal comfort and ventilation. Some air distribution ductwork is installed on rooftops, exposed directly to the outside environment. As such, there exist potential energy penalties related to externally installed ductwork. In order to evaluate the magnitude of these penalties, a case study was conducted of a one-story community college building, located in California`s Sacramento Valley. The majority of the building`s air distribution ductwork was located on the roof. Energy-related issues studied in this case included duct-related thermal losses (duct leakage and conduction), delivery effectiveness and efficiency, thermal comfort issues and the effect of a roof retrofit (additional insulation and a reflective coating). The building in this study underwent a retrofit project involving additional insulation and a highly reflective coating applied to the roof and ducts. As part of this project, methods were developed to analyze the air distribution system effectiveness independent of the introduction of outside air through an outside air damper. A simplified model was developed to predict the effectiveness and efficiency of the distribution system. The time frame of the retrofit allowed two separate three week monitoring periods. Despite the fact that the ducts started off with a conduction efficiency of 97%, the delivery efficiency was on average only 73% (with a supply side effectiveness of 78% and return effectiveness of 92%). This is due to the losses from the ducts being located on the roof. The retrofit increased the delivery efficiency to an average of 89% (with a supply side effectiveness of 90% and return effectiveness of 99%), reducing the average energy use for conditioning by 22%. The model predicted, on average, the results within 10%, or better, of measured results.
Date: July 1, 1996
Creator: Delp, W.W.; Matson, N. & Modera, M.P.
Partner: UNT Libraries Government Documents Department

Nuclear Criticality Safety Evaluation of the 9965, 9968, 9972, 9973, 9974, and 9975 Shipping Casks

Description: A Nuclear Criticality Safety Evaluation (NCSE) has been performed for the 9965, 9968, 9972, 9973, 9974, and 9975 SRS-designed shipping casks. This was done in support of the recertification effort for the 9965 and 9968, and the certification of the newly designed 9972-9975 series. The analysis supports the use of these packages as Fissile Class I for shipment of fissionable material from the SRS FB-Line, HB-Line, and from Lawrence Livermore national Laboratory. six different types of material were analyzed with varying Isotopic composition, of both oxide and metallic form. The mass limits required to support the fissile Class I rating for each of the envelopes are given in the Table below. These mass limits apply if DOE approves an exception as described in 10 CFR 71.55(c), such that water leakage into the primary containment vessel does not need to be considered in the criticality analysis. If this exception is not granted, the mass limits are lower than those shown below. this issue is discussed in detail in sections 5 and 6 of the report.One finding from this work is important enough to highlight in the abstract. The fire tests performed for this family of shipping casks indicates only minimal charring of the Celotex thermal insulation. Analysis of the casks with no Celotex insulation (assuming it has all burned away), results in values of k-eff that exceed 1.0. Therefore, the Celotex insulation must remain intact in order to guarantee sub criticality of the 9972-9975 family of shipping casks.
Date: February 26, 1999
Creator: Frost, R.L.
Partner: UNT Libraries Government Documents Department

Predicting moisture problems in low-slope roofing

Description: 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.
Date: November 1, 1998
Creator: Desjarlais, A.O. & Byars, N.A.
Partner: UNT Libraries Government Documents Department

Experimental and cost analyses of a one kilowatt-hour/day domestic refrigerator-freezer

Description: Over the past ten years, government regulations for energy standards, coupled with the utility industry`s promotion of energy-efficient appliances, have prompted appliance manufacturers to reduce energy consumption in refrigerator-freezers by approximately 40%. Global concerns over ozone depletion have also required the appliance industry to eliminate CFC-12 and CFC-11 while concurrently improving energy efficiency to reduce greenhouse emissions. In response to expected future regulations that will be more stringent, several design options were investigated for improving the energy efficiency of a conventionally designed, domestic refrigerator-freezer. The options, such as cabinet and door insulation improvements and a high-efficiency compressor were incorporated into a prototype refrigerator-freezer cabinet and refrigeration system. Baseline energy consumption of the original 1996 production refrigerator-freezer, along with cabinet heat load and compressor calorimeter test results, were extensively documented to provide a firm basis for experimentally measured energy savings. The goal for the project was to achieve an energy consumption that is 50% below in 1993 National Appliance Energy Conservation Act (NAECA) standard for 20 ft{sup 3} (570 l) units. Based on discussions with manufacturers to determine the most promising energy-saving options, a laboratory prototype was fabricated and tested to experimentally verify the energy consumption of a unit with vacuum insulation around the freezer, increased door thicknesses, a high-efficiency compressor, a low wattage condenser fan, a larger counterflow evaporator, and adaptive defrost control.
Date: May 1, 1997
Creator: Vineyard, E.A. & Sand, J.R.
Partner: UNT Libraries Government Documents Department

Impact of the temperature dependency of fiberglass insulation R-value on cooling energy use in buildings

Description: Building energy models usually employ a constant, room-temperature-measured value for the thermal resistance of fiberglass roof insulation. In summer, however, the mean temperature of roof insulation can rise significantly above room temperature, lowering the insulation`s thermal resistance by 10% to 20%. Though the temperature dependence of the thermal resistance of porous materials like fiberglass has been extensively studied, it is difficult to theoretically predict the variation with temperature of a particular fiberglass blanket, from first principles. Heat transfer within fiberglass is complicated by the presence of three significant mechanisms - conduction through air, conduction through the glass matrix, and radiative exchange within the matrix - and a complex, unknown internal geometry. Purely theoretical models of fiberglass heat transfer assume highly simplified matrix structures and require typically-unavailable information about the fiberglass, such as its optical properties. There is also a dearth of useful experimental data. While the thermal resistances of many individual fiberglass samples have been measured, there is only one practical published table of thermal resistance vs. both temperature and density. Data from this table was incorporated in the DOE-2 building energy model. DOE-2 was used to simulate the roof surface temperature, roof heat flux, and cooling energy consumption of a school bungalow whose temperature and energy use had been monitored in 1992. The DOE-2 predictions made with and without temperature variation of thermal conductivity were compared to measured values. Simulations were also run for a typical office building. Annual cooling energy loads and annual peak hourly cooling powers were calculated for the office building using both fixed and variable thermal conductivities, and using five different climates. The decrease in the R-value of the office building`s roof led to a 2% to 4% increase in annual cooling energy load.
Date: August 1, 1996
Creator: Levinson, R.; Akbari, H. & Gartland, L.
Partner: UNT Libraries Government Documents Department

Aging of polyurethane foam insulation in simulated refrigerator walls

Description: Laboratory data are presented on the thermal conductivity of polyurethane foam insulation in composite test panels that simulate refrigerator walls. The test panels consisted of a steel skin, an ABS plastic liner, and a polyurethane foam core. Foam cores were produced with three different blowing agents (CFC-11, HCFC-141b, and a HCFC-142/22 blend). Periodic thermal measurements have been made on these panels over a three and one half year period in an effort to detect aging processes. Data obtained on foam encased in the panels were compared with measurements on thin foam slices that were removed from similar panels. The data show that the encapsulation of the foam in the solid boundary materials greatly reduces the aging rate. The plan is presented for a follow-on project that is being conducted on the aging of foams blown with HCFC-141b, HFC-134a, HFC-245fa, and cyclopentane.
Date: October 1997
Creator: Wilkes, K. E.; Yarbrough, D. W. & Weaver, F. J.
Partner: UNT Libraries Government Documents Department

Insulation fact sheet

Description: Electricity bills, oil bills, gas bills - all homeowners pay for one or more of these utilities, and wish they paid less. Often many of us do not really know how to control or reduce our utility bills. We resign ourselves to high bills because we think that is the price we have to pay for a comfortable home. We encourage our children to turn off the lights and appliances, but may not recognize the benefits of insulating the attic. This publication provides facts relative to home insulation. It discusses where to insulate, what products to use, the decision making process, installation options, and sources of additional information.
Date: August 1997
Partner: UNT Libraries Government Documents Department

Aging of polyurethane insulation foamed with second- and third-generation blowing agents

Description: Results are presented on two studies of the effect of aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators. Both studies are cooperative projects between the Oak Ridge National Laboratory and the Appliance Research Consortium. The first study has been ongoing for four years and involves evaluation of second generation blowing agents: HCFC-141b and HCFC-142/22 blend with CFC-11 for comparison. The second study has recently started and involves third generation blowing agents: HFC-134a, HFC-245fa. and cyclopentane with HCFC-141b for comparison. Both studies consist of periodic thermal measurements on panels made with solid steel and/or plastic skins and a core of foam to simulate refrigerator walls, and measurements on thin slices with cut faces to characterize the core foam. Laboratory data are presented on four years of aging of panels containing second generation blowing agents. Preliminary data are presented for the third generation blowing agents. The data on panels are compared with predictions of computer models of foam aging.
Date: May 1998
Creator: Wilkes, K. E.; Gabbard, W. A. & Weaver, F. J.
Partner: UNT Libraries Government Documents Department

Thermal considerations for overpack designs in drum packages

Description: The design of the overpacks in drum packages, both in terms of thickness and materials of construction, greatly impact the ability of the package to accommodate heat source contents. The optimum overpack thermal protection needed is that which results in the lowest containment vessel temperature during both Hypothetical Accident Conditions (HAC) and Normal Conditions of Transport (NCT). For heat source packages, the use of very good or high efficiency insulating materials such as fiberboard and polyurethane results in high containment vessel temperatures during both NCT and HAC. Using a more modest or low efficiency insulating material would reduce the NCT and HAC material such as oak (low efficiency) would maintain a containment vessel with a content of 100 watts at a fraction of the temperature reported for very good or high efficiency insulating materials. Four inches of oak can prevent the containment vessel from exceeding 500{degrees}F during both NCT and HAC with 100 watts of contents, whereas using a high efficiency material the vessel would exceed 1000{degrees}F. 8 figs., 1 tab.
Date: September 1, 1997
Creator: Hensel, S. & Gromada, R.J.
Partner: UNT Libraries Government Documents Department

Radiation control coatings installed on federal buildings at Tyndall Air Force Base. Volume 1: Pre-coating monitoring and fresh coating results

Description: The US Department of Energy`s (DOE`s) Federal Energy Management Program (FEMP) supports efforts to reduce energy use and associated expenses in the federal sector. One such effort, the New Technology Demonstration Program (NTDP), seeks to evaluate new energy-saving US technologies and secure their more timely adoption by the US government. Through a partnership with a federal site, the utility serving the site, a manufacturer of an energy-related technology, and other organizations associated with these interests, DOE can evaluate a new technology. The results of the program give federal agency decision makers more hands-on information with which to validate a decision to utilize a new technology in their facilities. The partnership of these interests is secured through a cooperative research and development agreement (CRADA), in this case between Lockheed Martin Energy Research Corporation, the manager of the Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee, and ThermShield International, Ltd., the manufacturer of the technology. This is the first volume of a two-volume report that describes the effects of radiation control coatings installed on federal buildings at Tyndall Air Force Base (AFB) in Florida by ThermShield International. ORNL`s Buildings Technology Center (BTC) was assigned the responsibility for gathering, analyzing, and reporting on the data to describe the effects of the coatings. This volume describes the monitoring plan and its implementation, the results of pre-coating monitoring, the coating installation, results from fresh coatings compared to pre-coating results, and a plan to decommission the monitoring equipment. By including results from roofs at Tyndall AFB and from an outdoor test facility at the BTC, the data cover the range from poorly insulated to well-insulated roofs and two kinds of radiation control coatings on various roof membranes.
Date: February 1, 1997
Creator: Petrie, T.W. & Childs, P.W.
Partner: UNT Libraries Government Documents Department

Advanced Thermal Barrier Coating System Development

Description: The objectives of the program are to provide an improved Thermal Barrier Coating (TBC) system with increased temperature capability and improved reliability relative to current state of the art TBC systems. The development of such a coating system is essential to the ATS engine meeting its objectives. The base program consists of three phases: Phase I: Program Planning - Complete; Phase II: Development; and Phase III: Selected Specimen - Bench Test Work is being performed in Phase II and III of the program.
Date: March 31, 1999
Partner: UNT Libraries Government Documents Department