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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

The status of power supplies for primary electric propulsion in the U.S.A.

This paper reviews the status of and requirements on solar electric and nuclear electric power supplies for primary electric propulsion missions. The power supply requirements of power level, specific mass (kg/kWe) and lifetime are defined as a function of the mission and electric propulsion system characteristics for planetary missions. The technology status of planar and concentrator arrays is discussed. Nuclear reactors and thermoelectric, thermionic, Brayton and Rankine conversion technologies are reviewed, as well as recent nuclear power system design concepts and program activity. Technology projections for power supplies applicable to primary electric propulsion missions are included.

Jones, R. M.↗
NASA NTRS2005

Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

An advantage of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used for a number of beneficial purposes including: maintaining electronic components within a controlled temperature range, warming propulsion tanks and mobility actuators, and maintaining liquid propellants above their freezing temperature. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated large quantities of waste heat due to the low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-Watt Stirling Radioisotope Generator (SRG110) will have higher conversion efficiencies, thereby rejecting less waste heat at a lower temperature and may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of ~6 to 7 percent, reject their waste heat at the relatively high heat rejection temperature of 200 C. This is an advantage when rejecting heat to space; however, transferring heat to the internal spacecraft components requires a large and heavy radiator heat exchanger. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation of the RTG. The SRG110, with an efficiency around 22 percent and 50 C nominal housing surface temperature, can readily transfer the available waste heat directly via heat pipes, thermal straps, or fluid loops. The lower temperatures associated with the SRG110 avoid the chances of overheating other scientific components, eliminating the need for thermal shields. This provides the spacecraft designers more flexibility when locating the generator for a specific mission. A common misconception with high-efficiency systems is that there is not enough waste heat for spacecraft thermal management. This paper will dispel this misconception and investigate the use of a high-efficiency SRG110 for spacecraft thermal management and outline potential methods of waste heat utilization in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander). The advantages associated with the SRG110 as they relate to ease of assembly, less complex interfaces, and overall mass savings for a spacecraft will be highlighted.

Pantano, David R.↗
NASA NTRS2005

Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

One of the advantages of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used to maintain electronic components within a controlled temperature range, to warm propulsion tanks and mobility actuators, and to gasify liquid propellants. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated a very large quantity of waste heat due to the relatively low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-watt Stirling Radioisotope Generator (SRG110) will have much higher conversion efficiencies than their predecessors and therefore may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of approx. 6 to 7% and 200 C housing surface temperatures, would need to use large and heavy radiator heat exchangers to transfer the waste heat to the internal spacecraft components. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation by using the heat exchangers or additional shields. The SRG110, with an efficiency around 22% and 50 C nominal housing surface temperature, can use the available waste heat more efficiently by more direct heat transfer methods such as heat pipes, thermal straps, or fluid loops. The lower temperatures allow the SRG110 much more flexibility to the spacecraft designers in configuring the generator without concern of overheating nearby scientific instruments, thereby eliminating the need for thermal shields. This paper will investigate using a high efficiency SRG110 for spacecraft thermal management and outline potential methods in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander) to illustrate the advantages with regard to ease of assembly, less complex interfaces, and overall mass savings.

Pantano, David R.↗
DOE OSTI2025

Cyclic Olefin Copolymer based Alkaline Exchange Polymers and Reinforced Membranes

In this project, a team of researchers from Rensselaer Polytechnic Institute developed high performance, low-cost alkaline conductors which can improve efficiency and lower cost of energy storage and conversion technology. The Rensselaer Polytechnic Institute team has developed a highly ion conductive, chemically stable, and mechanically durable alkaline membrane materials. Such membranes will serve as a critical component in electrochemical devices when energy is generated from renewable sources (e.g., sun and wind) or hydrogen fuel. The use of alkaline membrane in electrochemical reactions allows us to replace expensive platinum catalysts with less expensive, earth abundant metals as catalysts, offering huge economic advantages in renewable energy technology.

30 DIRECT ENERGY CONVERSION↗
NASA NTRS1979

Massively parallel information processing systems for space applications

NASA is developing massively parallel systems for ultra high speed processing of digital image data collected by satellite borne instrumentation. Such systems contain thousands of processing elements. Work is underway on the design and fabrication of the 'Massively Parallel Processor', a ground computer containing 16,384 processing elements arranged in a 128 x 128 array. This computer uses existing technology. Advanced work includes the development of semiconductor chips containing thousands of feedthrough paths. Massively parallel image analog to digital conversion technology is also being developed. The goal is to provide compact computers suitable for real-time onboard processing of images.

Schaefer, D. H.↗
NASA NTRS1976

Clean fuels from biomass

The paper discusses the U.S. resources to provide fuels from agricultural products, the present status of conversion technology of clean fuels from biomass, and a system study directed to determine the energy budget, and environmental and socioeconomic impacts. Conversion processes are discussed relative to pyrolysis and anaerobic fermentation. Pyrolysis breaks the cellulose molecules to smaller molecules under high temperature in the absence of oxygen, wheras anaerobic fermentation is used to convert biomass to methane by means of bacteria. Cost optimization and energy utilization are also discussed.

Hsu, Y.-Y.↗
NASA NTRS2015

Advanced Stirling Convertor (ASC) Technology Maturation

The Advanced Stirling Convertor (ASC) development effort was initiated by NASA Glenn Research Center (GRC) with contractor Sunpower Inc. to develop high efficiency thermal-to-electric power conversion technology for NASA Radioisotope Power Systems. Early successful performance demonstrations led to the expansion of the project as well as adoption of the technology by the Department of Energy (DOE) and system integration contractor Lockheed Martin Space Systems Company as part of the Advanced Stirling Radioisotope Generator (ASRG) flight project. The ASRG integrates a pair of ASCs to convert the heat from a pair of General Purpose Heat Source (GPHS) modules into electrical power. The expanded NASA ASC effort included development of several generations of ASC prototypes or Engineering Units to help prepare the ASC technology and Sunpower for flight implementation. Sunpower later had two parallel contracts allowing the last of the NASA Engineering Units called ASC-E3 to serve as pathfinders for the ASC-F flight convertors being built for DOE. The ASC-E3 convertors utilized the ASC-F flight specifications and were built using the ASC-F design and process documentation. Shortly after the first ASC-F Pair achieved initial operation, due to budget constraints, the DOE ASRG flight development contract was terminated. NASA continues to invest in the development of Stirling RPS technology including continued production of the ASC-E3 convertors, seven of which have been delivered with one additional unit in production. Starting in FY2015, Stirling Convertor Technology Maturation has been reorganized as an element of the RPS Stirling Cycle Technology Development (SCTD) Project and long-term plans for continued Stirling technology advancement are in reformulation. This paper provides a status on the ASC project, an overview of advancements made in the design and production of the ASC at Sunpower, and a summary of acceptance tests, reliability tests, and tactical tests at NASA GRC that demonstrate the capabilities of the ASC.

radioisotope↗
NASA NTRS2016

Advanced Stirling Convertor (ASC) Technology Maturation

The Advanced Stirling Convertor (ASC) development effort was initiated by NASA Glenn Research Center with contractor Sunpower, Inc., to develop high-efficiency thermal-to-electric power conversion technology for NASA Radioisotope Power Systems (RPSs). Early successful performance demonstrations led to the expansion of the project as well as adoption of the technology by the Department of Energy (DOE) and system integration contractor Lockheed Martin Space Systems Company as part of the Advanced Stirling Radioisotope Generator (ASRG) flight project. The ASRG integrates a pair of ASCs to convert the heat from a pair of General Purpose Heat Source (GPHS) modules into electrical power. The expanded NASA ASC effort included development of several generations of ASC prototypes or engineering units to help prepare the ASC technology and Sunpower for flight implementation. Sunpower later had two parallel contracts allowing the last of the NASA engineering units called ASC-E3 to serve as pathfinders for the ASC-F flight convertors being built for DOE. The ASC-E3 convertors utilized the ASC-F flight specifications and were built using the ASC-F design and process documentation. Shortly after the first ASC-F pair achieved initial operation, due to budget constraints, the DOE ASRG flight development contract was terminated. NASA continues to invest in the development of Stirling RPS technology including continued production of the ASC-E3 convertors, seven of which have been delivered with one additional unit in production. Starting in fiscal year 2015, Stirling Convertor Technology Maturation has been reorganized as an element of the RPS Stirling Cycle Technology Development (SCTD) Project and long-term plans for continued Stirling technology advancement are in reformulation. This paper provides a status on the ASC project, an overview of advancements made in the design and production of the ASC at Sunpower, and a summary of acceptance tests, reliability tests, and tactical tests at NASA Glenn that demonstrate the capabilities of the ASC.

Stirling cycle↗
DOE OSTI2024

Abstract for CRADA between National Energy Technology Laboratory and OMC Hydrogen, Inc

The National Energy Technology Laboratory (NETL) and OMC Thermochemistry (Participant) will collaborate in the development of a better understanding of the current domestic data of TRL 7+ syngas conversion technologies and their current and potential markets. This will provide a basis for future comparative life cycle emission and techno-economic evaluations with the participant’s syngas production process using industrial and biogenic CO2 conversion approaches.

10 SYNTHETIC FUELS↗
DOE OSTI2020

Nanoporous Catalysts for Biomass Conversion

Transforming plant biomass to biofuel and chemicals has become a global effort as results of increasing fuel demand but diminishing fossil-based energy preservation and rising concerns of climate and environmental impact. Various conversion routes involving thermochemical and biological conversions have been established and well-studied. Heterogeneous catalysis is playing a critical role in the biomass conversion and, with some unique catalytic properties, nanoporous catalysts have been extensively utilized in catalytic process of biomass conversion and exhibited exciting catalytic performance. This chapter will be devoted to nanoporous catalysts used in biomass conversion. It will start with a brief introduction of current biomass conversion technologies and then a detailed review of the application of various nanoporous materials in a large diversity of catalytic reactions in biomass conversion. The nanoporous materials include zeolites and zeotypes, metal-organic frameworks (MOFs), nanoporous carbons and carbon nitrides, nanoporous oxides, hydroxides and complex oxide forms, porous organic polymers (POPs), and porous metals.

Shi, Hui↗
NASA NTRS2022

Nuclear Power Concepts and Development Strategies for High-Power Electric Propulsion Missions to Mars

Under the Mars Transportation Assessment Study (MTAS), NASA and the Department of Energy are performing analyses and generating concepts for crewed nuclear electric propulsion (NEP) missions to Mars. This report presents the results of trade studies and concept development for the nuclear electric power system, consisting of the fission reactor, radiation shielding, power conversion, heat rejection, and power management and distribution (PMAD). The nuclear power team completed trade studies to evaluate different reactor and power conversion technologies and developed preliminary concepts for the crew shielding, waste heat radiators, and PMAD. The initial results suggest that a modified terrestrial microreactor combined with supercritical CO2 Brayton conversion could be used to perform the crew and cargo missions with satisfactory performance and modest risk. The report includes preliminary development strategies that could bring the NEP technology to fruition for Mars missions in the late 2030s or early 2040s.

Lee S. Mason↗
DOE OSTI2023

Toward High Conversion Efficiency of Thermoelectric Modules through Synergistical Optimization of Layered Materials

Abstract Waste‐heat electricity generation using high‐efficiency solid‐state conversion technology can significantly decrease dependence on fossil fuels. Here, a synergistical optimization of layered half‐Heusler (hH) materials and module to improve thermoelectric conversion efficiency is reported. This is realized by manufacturing multiple thermoelectric materials with major compositional variations and temperature‐gradient‐coupled carrier distribution by one‐step spark plasma sintering. This strategy provides a solution to overcome the intrinsic concomitants of the conventional segmented architecture that only considers the matching of the figure of merit ( zT ) with the temperature gradient. The current design is dedicated to temperature‐gradient‐coupled resistivity and compatibility matching, optimum zT matching, and reducing contact resistance sources. By enhancing the quality factor of the materials by Sb‐vapor‐pressure‐induced annealing, a superior zT of 1.47 at 973 K is achieved for (Nb, Hf)FeSb hH alloys. Along with the low‐temperature high‐ zT hH alloys of (Nb, Ta, Ti, V)FeSb, the single stage layered hH modules are developed with efficiencies of ≈15.2% and ≈13.5% for the single‐leg and unicouple thermoelectric modules, respectively, under Δ T of 670 K. Therefore, this work has a transformative impact on the design and development of next‐generation thermoelectric generators for any thermoelectric material families.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1978

Impact of novel energy sources: OTEC, wind, goethermal, biomass

Alternate energy conversion methods such as ocean thermal energy conversion (OTEC), wind power, geothermal wells and biomass conversion are being explored, and re-examined in some cases, for commercial viability. At a time when United States fossil fuel and uranium resources are found to be insufficient to supply national needs into the twenty-first century, it is essential to broaden the base of feasible energy conversion technologies. The motivations for development of these four alternative energy forms are established. Primary technical aspects of OTEC, wind, geothermal and biomass energy conversion systems are described along with a discussion of relative advantages and disadvantages of the concepts. Finally, the sentiment is voiced that each of the four systems should be developed to the prototype stage and employed in the region of the country and in the sector of economy which is complimentary to the form of system output.

Roberts, A. S., Jr.↗
NASA NTRS2014

NASA Glenn Research Center Support of the ASRG Project

A high efficiency radioisotope power system is being developed for long-duration NASA space science missions. The U.S. Department of Energy (DOE) managed a flight contract with Lockheed Martin Space Systems Company (LMSSC) to build Advanced Stirling Radioisotope Generators (ASRGs), with support from NASA Glenn Research Center (GRC). Sunpower Inc. held two parallel contracts to produce Advanced Stirling Convertors (ASCs), one with DOELockheed Martin to produce ASC-F flight units, and one with GRC for the production of ASC-E3 engineering unit pathfinders that are built to the flight design. In support of those contracts, GRC provided testing, materials expertise, government furnished equipment, inspections, and related data products to DOELockheed Martin and Sunpower. The technical support includes material evaluations, component tests, convertor characterization, and technology transfer. Material evaluations and component tests have been performed on various ASC components in order to assess potential life-limiting mechanisms and provide data for reliability models. Convertor level tests have been used to characterize performance under operating conditions that are representative of various mission conditions. Technology transfers enhanced contractor capabilities for specialized production processes and tests. Despite termination of flight ASRG contract, NASA continues to develop the high efficiency ASC conversion technology under the ASC-E3 contract. This paper describes key government furnished services performed for ASRG and future tests used to provide data for ongoing reliability assessments.

Technology Transfer↗
DOE OSTI2021

Microalgae to biofuels through hydrothermal liquefaction: Open-source techno-economic analysis and life cycle assessment

Hydrothermal liquefaction is a promising conversion technology in algae biofuel research due to its ability to agnostically convert proteins, carbohydrates, and lipids to biocrude. The high-temperature conditions that define this conversion process require the material to maintain a subcritical liquid state, which complicates the assessment of accurate thermochemical properties due to the required pressure. To clarify this issue, this work compares the estimated performance of algal hydrothermal liquefaction between different thermodynamic models. A process model was developed in Aspen Plus from a robust assessment of current literature. Techno-economic assessment and life-cycle assessment metrics are derived from this model and used as key performance indicators. The baseline fuel price contribution of hydrothermal liquefaction is $0.45 per liter gasoline equivalent. Independently decreasing the temperature from 350 °C to 260 °C while maintaining yield reduces the conversion cost by 19%, illustrating the importance of understanding the high-temperature thermodynamics of the system. Different thermodynamic property models can vary fuel conversion cost results by $0.07 per liter gasoline equivalent. The baseline global warming potential is +23 g CO 2 eq MJ -1 and the net energy ratio is 0.30. Environmental metrics beyond global warming potential and net energy ratio are also discussed for the first time. Uncertainties in conversion performance are bounded through a scenario analysis that manipulates parameters such as product yield and nutrient recycle to produce a range of economic and environmental metrics. The report is supplemented with an open source model to support future hydrothermal liquefaction assessments and accelerate the development of commercial-scale systems.

09 BIOMASS FUELS↗
DOE OSTI2025

Understanding and controlling the fundamental photochemistry of protonic solar energy conversion (Final Scientific/Technical Report)

The selectivity and activity of most fuel-forming reactions are tunable by the concentration of electrons, holes, protons, and/or hydroxides. That is one reason why traditional solar energy conversion processes are used to drive these reactions, where light directly increases the concentration of electrons and holes. We, instead, took a different approach, using light to increase the concentration of protons and/or hydroxides. For this, we leveraged photophysical and solid-state physics theories, techniques, and design strategies previously developed for the study of traditional solar energy conversion processes. We designed and fabricated several materials platforms based on molecular photoacid and photobase dyes coupled with ion-exchange polymer membranes and assessed their fundamental photoelectrochemistry. We demonstrated control over built-in electric potentials, photovoltages, proton-transfer kinetics, and efficiency limits to our approach. Understanding the basic science of these dye-sensitized protonic membranes and their photochemical mechanisms is of use to the DOE-relevant processes of solar photochemical fuel formation, solar photodialytic desalination, and solar cells. Moreover, functional materials that we developed from this project may be of use to several broad-reaching fields and may provide the foundation for a completely new, inexpensive, and robust solar energy conversion technology.

14 SOLAR ENERGY↗
NASA NTRSDate not supplied

Nuclear Power Concepts for High-Power Electric Propulsion Missions to Mars

Under the Mars Transportation Assessment Study, NASA and DOE are performing analyses and generating concepts for crewed Nuclear Electric Propulsion (NEP) missions to Mars. This paper presents the results of trade studies and concept development for the nuclear electric power system, consisting of the fission reactor, radiation shielding, power conversion, heat rejection and power management & distribution (PMAD). The nuclear power team completed trade studies to evaluate different reactor and power conversion technologies and developed preliminary concepts for the crew shielding, waste heat radiators, and PMAD. The initial results suggest that a modified terrestrial microreactor combined with supercritical CO2 Brayton conversion could be used to perform the crew and cargo missions with satisfactory performance and modest risk.

Lee Mason↗