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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Test-Derived Effective Emittance for Cassini MLI Blankets and Heat Loss Characteristics in the Vicinity of Seams

Multilayer insulation (MLI) blankets on the Cassini spacecraft will experience temperatures in the wide range of -200 to 360°C. Besides reducing heat loss, the MLI blankets will also serve, with standoffs, the purpose of micrometeoroid protection. Four major blanket layup configurations ??will be utilized on Cassini. Since definitive thermal properties for these layups were not available, thermal vacuum tests were conducted for their determination.

multilayer↗
NASA NTRS1982

Heat loss and drag of spherical drop tube samples

Analysis techniques for three aspects of the performance of the NASA/MSFC 32 meter drop tube are considered. Heat loss through the support wire in a pendant drop sample, temperature history of a drop falling through the drop tube when the tube is filled with helium gas at various pressures, and drag and resulting g-levels experienced by a drop falling through the tube when the tube is filled with helium gas at various pressures are addressed. The developed methods apply to systems with sufficiently small Knudsen numbers for which continuum theory may be applied. Sample results are presented, using niobium drops, to indicate the magnitudes of the effects. Helium gas at one atmosphere pressure can approximately double the amount of possible undercooling but it results in an apparent gravity levels of up to 0.1 g.

Wallace, D. B.↗
NASA NTRS1983

Regeneration efficiency, shuttle heat loss and thermal conductivity in epoxy-composite annualr gap regenerators from 4K to 80K

A test apparatus designed to simulate a section of a Stirling cycle cryocooler was built. Measurements of regeneration efficiency, shuttle heat loss and thermal conductivity reported for several regenerator test sections. The test composites were epoxy glass, epoxy glass with lead particles, epoxy glass with activated charcoal and epoxy graphite. Losses measured for these materials were approximately the same. Losses are in good agreement with those calculated theoretically for an epoxy glass (C-10) composite. The implications of these results on cryocooler design are discussed.

Myrtle, K.↗
NASA NTRS1974

Cycles in metabolism and heat loss

Using calorimetric techniques, subjects' metabolism, thermoregulation, and body temperatures were monitored continuously for 24-hour days, using three types of experimental routines. A water cooling garment (WCG) was used for direct calorimetry, while partitional calorimetry was used to establish a non-suited comparison for one of the routines. In this replicated routine, called the quiet day, the subjects were sedentary throughout the daytime hours and slept normally at night. Results indicate that the WCG may act to reduce 24-hour total oxygen consumption (VO2) or heat production, possibly due to the lowered energy cost of thermoregulation.

Annis, J. F.↗
NASA NTRS1977

Application of airborne infrared technology to monitor building heat loss

The application of airborne infrared technology to the requirements for energy conservation in buildings was studied. Quantitative airborne data of the City of Ypsilanti, Michigan, were collected and processed to identify roof temperatures. A thermal scanner was flown at an altitude of 1,200 feet with two thermal bands 8.2-9.3 micrometers and 10.4-12.5 micrometers recorded by an analog system. Calibration was achieved by standard hot and cold plates. Using a thermal model to interpret ceiling insulation status, environmental factors were found to influence the relation between roof temperature and insulation. These include interior and sky temperatures, roofing materials, and the pitch and orientation of the roof. A follow-up mail survey established the ability to identify insulated and uninsulated houses from the airborne infrared data.

Tanis, F. J.↗
NASA NTRS1995

Aerodynamic, unsteady, kinetic and heat loss effects on the dynamics and structure of weakly-burning flames

The first objective of the program is to introduce the meritorious counterflow methodology in microgravity in order to quantify the steady and unsteady characteristics of weakly-burning premixed and diffusion flames for a wide variety of conditions including elevated pressures. Subsequently, through detailed modeling and comparisons with the experimental data, to provide physical insight into the elementary mechanisms controlling the flame response. The configuration offers good control over the parameters of interest and can be modelled closely. The knowledge which will be gained from the counterflow flames will be subsequently used to analyze near-limit phenomena related to other configurations by conducting detailed numerical simulations including multidimensional ones. Among the problems to be analyzed are the downward and upward propagation of near-limit flames in tubes and phenomena observed in spherical and cylindrical geometries.

Egolfopoulos, Fokion N.↗
DOE OSTI2021

System and method for reducing heat loss from FRC bulk plasma

According to various embodiments, an FRC fusion reactor is disclosed. The FRC fusion reactor includes a main chamber containing an FRC core and an energy and ash removal shell (EARS). The FRC fusion reactor further includes at least one divertor chamber connected to the main chamber via a divertor throat. The divertor chamber includes a plasma extruder positioned on a major axis of the FRC fusion reactor and a controllable distance along the major axis from the divertor throat. The plasma extruder has a diameter approximately ½ a diameter of the divertor throat and is configured to block plasma flow towards the FRC core to create a gap region between the FRC core and the EARS.

Cohen, Samuel A.↗
NASA NTRS1982

Restraint hypothermia in cold-exposed rats at 3 G and 1 G

The relationship between heat loss, heat production, and hypothermia was investigated in experiments with rats which determined if hypergravity affects heat production by altering oxygen consumption and if restraint modifies the ability of the rats to activate thermogenic mechanisms after cold exposure in a hypergravic field. Restrained and unrestrained rats were exposed for 1 hr periods to 1 G and 3 G at ambient temperatures of 24 C or 10 C, and the rate of oxygen consumption, the core temperatures, and the tail temperatures were measured. Results show that thermoregulatory mechanisms are impaired when rats are exposed to 3 G fields, and at 24 C as well as at 10 C this impairment leads to an inappropriate increase in heat loss.

Monson, C. B.↗
DOE OSTI2021

Energy use of piperazine with the advanced stripper from pilot plant testing

Here, piperazine with the Advanced Stripper (PZAS™) was tested at the National Carbon Capture Center (NCCC) at coal and NGCC conditions. Energy performance was measured with accounting for heat loss. The net heat duty was found to be identical at 2.45 GJ/tonne for both 4 and 12% CO 2 at 90% CO 2 removal. The average measured heat loss was 0.38 GJ/tonne and represented 30% of the gross heat rate. For PZAS, the warm rich piping before the control valve is the largest in surface area. Heat loss at this location increased heat duty by 80% of the heat loss value. Therefore, the total heat duty was decreased by 80% of the heat loss. The Independence™ model was validated using 112 steady-state pilot plant runs and predicted average net heat duty with an error of 9% and lean loading with an error of 10%. The model was used to simulate process impacts of heat loss for the PZAS and simple stripper configurations. For both strippers, heat loss was found to impact heat duty at locations other than just the steam heater. While heat loss in the steam heater was the most important for PZAS, heat loss in the column was the most important for the simple stripper due to a large top-side pinch and CO 2 reabsorption at the same location. CO 2 reabsorption in PZAS occurred only at high heat loss values (~0.14 GJ/hr), compared to low heat loss values (~ 0.03 GJ/hr) in the PZ-simple stripper. Excessive packing in the PZ-simple stripper caused a large top-side pinch at 0.23 mol/mol lean loading, making the column very sensitive to heat loss. Heat loss in the PZ-simple stripper increased heat duty by 120–150% at typical heat loss values and lean loading of 0.23 mol/mol. Heat loss in the MEA-simple stripper only increased heat duty by 1–13% in a typical lean loading range of 0.1–0.2 mol/mol. A large bottom side pinch at low lean loading for 7 m MEA made the effect of heat loss less pronounced.

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DOE OSTI2021

Evaluation of Energy Efficiency Performance of Heated Windows

Fenestration systems are widely used across the world. There is expansive research on window configurations, frames, and glazing technology, but not enough research has been published on reducing window heat loss through heat application to a pane. The presented study attempted to evaluate the performance of heated windows by developing an experimental setup to test a window at various temperatures by varying the power input to the window. Heated double pane window was installed in an insulated box. A temperature gradient was developed across the window by cooling one side of the window using gel-based ice packs. The other face of the window was heated by enabling power at different wattages through the window. The temperature of the inside and outside panes, current and voltage input, and temperature of the room and box were recorded. The data was used to calculate the apparent effective resistance of the window when not being heated vs. when being heated. The study concluded that, when window temperature was maintained close to the room temperature, the heated double pane window is effective in reducing heat loss by as much as 50% as compared to a non-heated double pane window. When temperature of the window was much higher than the room temperature, the heat loss through the window increased beyond that of a non-heated window. The issues encountered during the current stages of experiments are noted, and recommendations are provided for future studies.

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