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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Role of Intense Arctic Storm in Accelerating Summer Sea Ice Melt: An In Situ Observational Study

Abstract Intense storms have been more frequently observed in the Arctic during recent years, in coincidence with extreme sea ice loss events. However, it is still not fully understood how storms drive such events due to deficient observations and modeling discrepancies. Here we address this problem by analyzing in situ observations acquired during an Arctic expedition, which uniquely captured an intense storm in summer 2016. The result shows a pronounced acceleration of sea ice loss during the storm process. Diagnostic analysis indicates a net energy loss at the ice surface, not supporting the accelerated melting. Although the open water surface gained net heat energy, it was insufficient to increase the mixed‐layer temperature to the observed values. Dynamic analysis suggests that storm‐driven increase in ocean mixing and upward Ekman pumping of the Pacific‐origin warm water tremendously increased oceanic heat flux. The thermal advection by the Ekman pumping led to a warmed mixed layer by 0.05°C–0.12°C and, in consequence, an increased basal sea ice melt rate by 0.1–1.7 cm day −1 .

58 GEOSCIENCES↗
NASA NTRS1971

Thermomechanical piston pump development

A thermally powered reciprocating pump has been devised to replace or augment an electric pump for the transport of temperature-control fluid on the Thermoelectric Outer Planet Spacecraft (TOPS). The thermally powered pump operates cyclically by extracting heat energy from the fluid by means of a vapor-pressure expansion system and by using the heat to perform the mechanical work of pumping. A feasibility test unit has been constructed to provide an output of 7 cu in during a 10- to 100-second cycle. It operates with a fluid input temperature of 200 to 300 F and a heat sink temperature of 0 to 30 F.

Sabelman, E. E.↗
NASA NTRS1981

Rub energetics of compressor blade tip seals

The rub mechanics of aircraft gas turbine engine compressor abradable blade tip seals was studied at simulated engine conditions. In 12 statistically planned, instrumented rub tests using single titanium blades and fiber-metal rubstrips the rub velocity, incursion rate, incursion depth, blade thickness, and abradable strength were varied to determine the effects on rub energy, heat split between the blade, rubstrip surface and rub debris, and blade and seal wear. The rub energies were found to be most significantly affected by the incursion rate while rub velocity and blade thickness were of secondary importance. In five additional rub tests using single nickel alloy blades and multiple titanium alloy blades, rub energy and wear effects were found to be similar for titanium and nickel alloy blades while rub energies increased for multiple blades relative to single blade test results.

Laverty, W. F.↗
NASA NTRS1978

Absorption of solar radiation by alkali vapors

A theoretical study of the direct absorption of solar radiation by the working fluid of high temperature, high efficiency energy converters has been carried out. Alkali vapors and potassium vapor in particular were found to be very effective solar absorbers and suitable thermodynamically for practical high temperature cycles. Energy loss via reradiation from a solar boiler was shown to reduce the overall efficiency of radiation-heated energy converters, although a simple model of radiation transfer in a potassium vapor solar boiler revealed that self-trapping of the reradiation may reduce this loss considerably. A study was also made of the requirements for a radiation boiler window. It was found that for sapphire, one of the best solar transmitting materials, the severe environment in conjunction with high radiation densities will require some form of window protection. An aerodynamic shield is particularly advantageous in this capacity, separating the window from the absorbing vapor to prevent condensation and window corrosion and to reduce the radiation density at the window.

Mattick, A. T.↗
DOE OSTI2020

Redox-active oxide materials for thermal energy storage

Thermochemical storage materials having the general formula A x A′ 1-x B y B′ 1-y O 3-δ , where A=La, Sr, K, Ca, Ba, Y and B=Mn, Fe, Co, Ti, Ni, Cu, Zr, Al, Y, Cr, V, Nb, Mo, are disclosed. These materials have improved thermal storage energy density and reaction kinetics compared to previous materials. Concentrating solar power thermochemical systems and methods capable of storing heat energy by using these thermochemical storage materials are also disclosed.

14 SOLAR ENERGY↗
DOE OSTI2020

Redox-active oxide materials for thermal energy storage

Thermochemical storage materials having the general formula AxA′1-xByB′1-yO3-δ, where A=La, Sr, K, Ca, Ba, Y and B=Mn, Fe, Co, Ti, Ni, Cu, Zr, Al, Y, Cr, V, Nb, Mo, are disclosed. These materials have improved thermal storage energy density and reaction kinetics compared to previous materials. Concentrating solar power thermochemical systems and methods capable of storing heat energy by using these thermochemical storage materials are also disclosed.

14 SOLAR ENERGY↗
DOE OSTI2022

Redox-active oxide materials for thermal energy storage

Thermochemical storage materials having the general formula AxA′1-xByB′1-yO3-δ, where A=La, Sr, K, Ca, Ba, Y and B=Mn, Fe, Co, Ti, Ni, Cu, Zr, Al, Y, Cr, V, Nb, Mo, are disclosed. These materials have improved thermal storage energy density and reaction kinetics compared to previous materials. Concentrating solar power thermochemical systems and methods capable of storing heat energy by using these thermochemical storage materials are also disclosed.

Babiniec, Sean M.↗
DOE OSTI2024

Pushing the Envelope-Moving Dynamic Building Envelope Thermal Energy Storage Systems Mainstream: Preprint

Buildings contribute to nearly 40% of the U.S. national energy consumption and a significant portion of CO2 emissions. More importantly, disadvantaged communities are disproportionately affected by energy burden and thermal discomfort in their homes. This paper will discuss two novel DOE's BTO supported thermal energy storage (TES) integrated dynamic building envelope technologies, their ability to harvest ambient energy, and improve energy efficiency by reducing HVAC loads and peak electricity demand while enhancing energy and thermal resilience in buildings. The paper will also discuss the recent advancements that have made these systems more affordable and easier to integrate into new and existing buildings. The first solution is a thermally anisotropic building envelope (TABE) system that can redirect ambient thermal energy (heat or coolness) from diurnal outdoor conditions, solar irradiance, and night sky radiation from the envelope to a hydronic loop. The redirected thermal energy can be stored in a TABE-integrated thermal energy storage system and use the stored energy to offset HVAC energy use and peak demand. The second solution is an innovative plug-and-play thermal switch in the form of insertable plugs integrated with a phase change material (PCM). The plug can vary its thermal resistance based on the indoor and outdoor conditions, thus allowing preferential directional heat flow, and enhancing utilization of free ambient cooling and heating to charge/discharge the PCM, much like a solid-state economizer. While the fist solution can be actively controlled, the second solution is passive, requiring no external power, and work solely based on the ambient temperature.

anisotropic envelope↗
DOE OSTI2024

Open-cycle thermochemical energy storage for building space heating: Practical system configurations and effective energy density

Salt-hydrate thermochemical materials (TCM) are promising candidates for energy storage systems for building space heating due to their high theoretical energy density and the need for low regeneration temperature. However, water vapor is required to drive the hydration process of the TCM reactor, which poses a challenge during winter when water vapor is typically scarce. Using indoor air directly lowers the building's humidity to an unconformable level in practice, while the cold outdoor air contains limited moisture. Here we consider different integration strategies for open-cycle TCM reactors in buildings and develop a model to simulate their thermal performance across diverse buildings and climates, specifically for building space heating. The potential energy densities and the levelized cost of storage of the TCM reactor are evaluated in practical scenarios to demonstrate the load-shifting potential of TCM systems for heating applications. We use a strontium chloride (SrCl 2 )-based composite as the baseline and explore the impact of various reactor and material changes to the energy density and levelized cost of storage.

25 ENERGY STORAGE↗
NASA NTRS2008

Self-Powered Wireless Sensors

NASA's integrated vehicle health management (IVHM) program offers the potential to improve aeronautical safety, reduce cost and improve performance by utilizing networks of wireless sensors. Development of sensor systems for engine hot sections will provide real-time data for prognostics and health management of turbo-engines. Sustainable power to embedded wireless sensors is a key challenge for prolong operation. Harvesting energy from the environment has emerged as a viable technique for power generation. Thermoelectric generators provide a direct conversion of heat energy to electrical energy. Micro-power sources derived from thermoelectric films are desired for applications in harsh thermal environments. Silicon based alloys are being explored for applications in high temperature environments containing oxygen. Chromium based p-type Si/Ge alloys exhibit Seebeck coefficients on the order of 160 micro V/K and low thermal conductance of 2.5 to 5 W/mK. Thermoelectric properties of bulk and thin film silicides will be discussed

Dynys, Fred↗
DOE OSTI2024

Pushing the Envelope—Moving Dynamic Building Envelope Thermal Energy Storage Systems Mainstream

Buildings contribute to nearly 40% of the U.S. national energy consumption and a significant portion of CO2 emissions. More importantly, disadvantaged communities are disproportionately affected by energy burden and thermal discomfort in their homes. This paper will discuss two novel DOE's BTO supported thermal energy storage (TES) integrated dynamic building envelope technologies, their ability to harvest ambient energy, and improve energy efficiency by reducing HVAC loads and peak electricity demand while enhancing energy and thermal resilience in buildings. The paper will also discuss the recent advancements that have made these systems more affordable and easier to integrate into new and existing buildings. The first solution is a thermally anisotropic building envelope (TABE) system that can redirect ambient thermal energy (heat or coolness) from diurnal outdoor conditions, solar irradiance, and night sky radiation from the envelope to a hydronic loop. The redirected thermal energy can be stored in a TABE-integrated thermal energy storage system and use the stored energy to offset HVAC energy use and peak demand. The second solution is an innovative plug-and-play thermal switch in the form of insertable plugs integrated with a phase change material (PCM). The plug can vary its thermal resistance based on the indoor and outdoor conditions, thus allowing preferential directional heat flow, and enhancing utilization of free ambient cooling and heating to charge/discharge the PCM, much like a solid-state economizer. While the fist solution can be actively controlled, the second solution is passive, requiring no external power, and work solely based on the ambient temperature.

Shrestha, Som↗
DOE OSTI2024

Energy impact of heating electrification in mid-rise multifamily buildings in mixed-humid climates

Decarbonizing the electric grid in conjunction with electrifying residential heating is a critical step to combat climate change. Heating in multifamily buildings with the existing natural gas-fired central boiler is a complex process that not only leads to overheating in some apartment units but also results in energy waste and high gas bills. In this study, we consider a multifamily building in New York City, USA, to evaluate the performance of five different heating systems, which represent a step-by-step transition from the conventional to a fully electrified heating system, and determine their impact on the site energy consumption and source CO 2 emissions. Results indicate that overheating in a multifamily building can raise the indoor temperature by as much as 8°C above comfortable limits. Transitioning from conventional steam radiators to cold climate heat pumps can reduce annual site heating energy by up to 70% and source CO 2 emissions by up to 21%.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Decarbonizing Cooking Appliances With Hydrogen

A novel hydrogen compatible heterogeneous burner prototype was engineered, fabricated, and evaluated for applications in cooking appliances. The key features targeted and accomplished under this effort included fuel flexibility, tolerance to high hydrogen concentrations (up to 85% in atmospheric design and 100% in premixed design), wide range of thermal power ratings, thermal cycling, reliability, and most importantly safety. The burner was operated in the range of 3000 – 12,000 Btu/h under all practical operating conditions (cold start, hot restart, fuel concentration variance). The heterogeneous oxidation burner technology was evaluated for overall performance targeting safety, reliability, emissions, fuel flexibility, and energy efficiency in a commercial RV and residential cooking range appliance prototypes. The burner demonstrated safe and reliable performance generating infrared heating energy without the consumption of any parasitic energy while using low-cost materials. Performance evaluation testing of the novel IR burner demonstrated fuel flexibility with hydrogen blended natural gas while significantly eliminating air pollutants like NOx and methane and increasing the energy efficiency by up to 20%.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Performance Evaluation of Engineered Geothermal Systems Using Discrete Fracture Network Simulations

Electrical power production from geothermal energy has a solid record of success for permeable reservoirs such as The Geysers in northern California and geothermal systems in Iceland and New Zealand, among other places. Such permeable reservoirs, however, represent only a small fraction of the available heat energy in the earth’s shallow crust. Most of the available energy resides in rocks with insufficient permeability and storage to produce commercial volumes of heated fluids.

15 GEOTHERMAL ENERGY↗
NASA NTRS1995

High Energy Antimatter Telescope (HEAT) Balloon Experiment

This grant supported our work on the High Energy Antimatter Telescope(HEAT) balloon experiment. The HEAT payload is designed to perform a series of experiments focusing on the cosmic ray positron, electron, and antiprotons. Thus far two flights of the HEAT -e+/- configuration have taken place. During the period of this grant major accomplishments included the following: (1) Publication of the first results of the 1994 HEAT-e+/- flight in Physical Review Letters; (2) Successful reflight of the HEAT-e+/- payload from Lynn Lake in August 1995; (3) Repair and refurbishment of the elements of the HEAT payload damaged during the landing following the 1995 flight; and (4) Upgrade of the ground support equipment for future flights of the HEAT payload.

Beatty, J. J.↗
NASA NTRS1979

Hydrogen as the solar energy translator

Many concepts are being investigated to convert sunlight to workable energy forms with emphasis on electricity and thermal energy. The electrical alternatives include direct conversion of photons to electricity via photovoltaic solar cells and solar/thermal production of electricity via heat-energy cycles. Solar cells, when commercialized, are expected to have efficiencies of about 12 to 14 percent. The cells would be active about eight hours per day. However, solar-operated water-splitting process research, initiated through JPL, shows promise for direct production of hydrogen from sunlight with efficiencies of up to 35 to 40 percent. The hydrogen, a valuable commodity in itself, can also serve as a storable energy form, easily and efficiently converted to electricity by fuel cells and other advanced-technology devices on a 24-hour basis or on demand with an overall efficiency of 25 to 30 percent. Thus, hydrogen serves as the fundamental translator of energy from its solar form to electrical form more effectively, and possibly more efficiently, than direct conversion. Hydrogen also can produce other chemical energy forms using solar energy.

Kelley, J. H.↗
NASA NTRS1994

Heat Flux Sensor

A heat flux microsensor developed under a NASP Small Business Innovation Research (SBIR) has a wide range of potential commercial applications. Vatell Corporation originally designed microsensors for use in very high temperatures. The company then used the technology to develop heat flux sensors to measure the rate of heat energy flowing in and out of a surface as well as readings on the surface temperature. Additional major advantages include response to heat flux in less than 10 microseconds and the ability to withstand temperatures up to 1,200 degrees centigrade. Commercial applications are used in high speed aerodynamics, supersonic combustion, blade cooling, and mass flow measurements, etc.

Source record↗