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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 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Advanced Stirling conversion systems for terrestrial applications

Under the Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories (SNLA) is developing heat engines for terrestrial Solar Distributed Heat Receivers. SNLA has identified the Stirling to be one of the most promising candidates for the terrestrial applications. The free-piston Stirling engine (FPSE) has the potential to meet the DOE goals for both performance and cost. The National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) is conducting free-piston Stirling activities which are directed toward a dynamic power source for space applications. Space power system requirements include high efficiency, very long life, high reliability and low vibration. The FPSE has the potential for future high power space conversion systems, either solar or nuclear. Generic free-piston technology is currently being developed by LeRC for DOE/ORNL for use with a residential heat pump under an Interagency Agreement. Since 1983, the SP-100 Program (DOD/NASA/DOE) is developing dynamic power sources for space. Although both applications (heat pump and space power) appear to be quite different, their requirements complement each other. A cooperative Interagency Agreement (IAA) was signed in 1985 with NASA Lewis to provide technical management for an Advanced Stirling Conversion System (ASCS) for SNLA. Conceptual design(s) using a free-piston Stirling (FPSE), and a heat pipe will be discussed. The ASCS will be designed using technology which can reasonably be expected to be available in the 1980's.

Shaltens, R. K.↗
DOE OSTI2025

Computational Investigation of a CO 2 Conversion Strategy via Diels–Alder Reaction in a Carbon Capture Solvent

Molecular-level insights into reactive separations are crucial for the design of new conversion pathways of carbon dioxide (CO 2 ). This work explores a postulated pathway that directs CO 2 to undergo inverse-electron-demand Diels–Alder reactions to produce heterocycles using the CO 2 chemically fixed on water-lean solvent molecules. Density functional theory calculations are applied to evaluate the lowest unoccupied molecular orbital (LUMO) energies of three types of reactants (1,3-butadiene, 1,3-cyclohexadiene, and 1,2,4,5-tetrazine) with various functional substituents. These calculations also provide a data set (5.8k data) for developing a machine learning model to efficiently predict LUMO energies. A computational screening of LUMO energies for an additional 47k diene and tetrazine candidates is performed, and a list of candidates with lowered LUMO energies by electron-withdrawing substituents is provided. These candidates are further examined by their reaction energy barriers computed from the interatomic potential or density functional theory. Two major energy barriers are identified, one for the proton transfer within the water-lean solvent and the other for the CO 2 transfer from the solvent molecule to the reactant candidate (diene or tetrazine). The functional substituents have a more significant impact on the second barrier but a very slight one on the first barrier. This exploratory work demonstrates a new possibility for guiding experimental efforts toward the chemical conversion of fixated CO 2 to value-added compounds.

Chemical reactions↗
DOE OSTI2022

Protonic Ceramics for Energy Storage & Electricity Generation with Ammonia (Final Report)

The commercial product resulting from this R&D project will enable cost-effective synthesis of the Carbon Neutral Liquid Fuel (CNLF) ammonia, a common chemical, at a small scale for energy and industrial applications using only intermittent renewable energy, water, and air as feedstocks. These products are also capable of producing electrical energy from the CNLF in a fuel cell mode of operation. Thus, the eventual commercial product enables both single direction production of either CLNF or electricity, or alternatively functions as a fully reversible, self-contained energy storage device. The renewed interest in developing electrolysis systems is driven, in part, by the burgeoning renewable, solar, and wind industries and the need for an energy conversion and storage technology that can convert intermittent solar and wind energy into the production of hydrogen. Electrolysis systems integrated into both distributed and central renewable power plants would utilize solar and wind energy as their primary power source to produce renewably generated hydrogen for local energy storage or chemical feedstock purposes. Ammonia is an excellent surrogate for hydrogen transportation. NH3 presents an attractive alternative to hydrogen as a working fluid in reversible devices towards a sustainable green energy-oriented future. Ammonia can be easily liquefied at room temperature at about 8 bar or at -33°C at ambient pressure. In contrast, the liquefaction temperature of hydrogen is -253°C at ambient pressure. NH3 has a significantly higher volumetric energy density (12.7 MJ/L) than compressed hydrogen (4.5 MJ/L at ~70 MPa) or liquefied hydrogen (8.5 MJ/L). Additionally, ammonia is a widely used raw material for agriculture fertilizer and thus has well-established storage, transport, and handling processes (about 180 million tons of ammonia are produced annually). Techno-economic analysis suggests ammonia is the least expensive fuel among hydrogen, gasoline, natural gas, liquefied petroleum gas, and methanol.

08 HYDROGEN↗
DOE OSTI2023

Imaging Nanoscale Energy Transport and Conversion with Ultrafast Electron Microscopy (Final Technical Report)

Light-matter interactions are ubiquitous in nature and reside at the heart of innumerable technologies. The cascade of processes that occur when a material absorbs a photon of light are exceedingly complex and are interwoven in both space and time, rendering precise determination of the atomic-scale and ultrafast mechanisms immensely challenging. The advent of methods for generating short pulses of light several decades ago led to major advances in understanding the initial moments of light absorption and the resultant effects, though directly interrogating the response of the atoms within the material continued to prove challenging. More recently, methods for generating ultrashort pulses of X-rays and fast electrons have opened the way to probing photoinduced structural dynamics of a wide range of matter in multiple phases. An especially promising laboratory-scale method is ultrafast electron microscopy (UEM), wherein the modalities of conventional transmission electron microscopes (imaging, diffraction, spectroscopy) are extended into the femtosecond temporal regime. Here, the ultrafast imaging and diffraction modalities of UEM were used to study the transient structural aspects of photoexcitation of semiconducting materials (e.g., spatially-resolved electron-phonon coupling, excitation and emission of acoustic phonons, and discrete nanoscale scattering processes). The project had three main objectives: (1) determination of the excitation mechanisms of dense, hypersonic charge-carrier waves and the spatially mediated means by which they couple to the lattice via coherent phonon emission, especially with UEM imaging, wherein effects of nanoscale structural and morphological features on the coupling and relaxation dynamics are expected to dictate nucleation sites and preferred wave vectors, (2) elucidation of photoinduced acoustic-phonon seeding, emergence, propagation, and decay over nanoscale crystal regions and especially with respect to local strain fields and atomic-scale disruptions in lattice order, and (3) interwoven with the first two were efforts aimed at realizing combined angstrom-femtosecond spatiotemporal imaging with UEM. The outcomes and impacts of this project were the generation of new knowledge with respect to fundamental light-matter interactions and, especially, the spatially-mediated excitation and evolution of the structural response of materials following coherent photoexcitation. Importantly, the spatial and temporal resolutions of the UEM imaging modalities used are well-suited for such studies and enable spatially-resolved mechanisms to be determined as a function of atomic order, structural features, and morphology. In addition, ultrafast crystallographic measurements were used to correlate real- and reciprocal-space dynamics in order to determine atomic-scale preferential wave vectors and ultrafast scattering mechanisms, especially as dictated by specimen boundary conditions. The obtained results, as detailed in peer-reviewed publications and presentations, illustrate the importance of ultrafast, angstrom-scale real-space imaging for developing a comprehensive understanding of energy transport and conversion in materials.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Multidimensional visualization of the dynamic evolution of Li metal via in situ/operando methods

The growing demands for high-energy density electrical energy storage devices stimulate the coupling of conversion-type cathodes and lithium (Li) metal anodes. While promising, the use of these “Li-free” cathodes brings new challenges to the Li anode interface, as Li needs to be dissolved first during cell operation. In this study, we have achieved a direct visualization and comprehensive analysis of the dynamic evolution of the Li interface. The critical metrics of the interfacial resistance, Li growth, and solid electrolyte interface (SEI) distribution during the initial dissolution/deposition processes were systematically investigated by employing multidimensional analysis methods. They include three-electrode impedance tests, in situ atomic force microscopy, scanning electrochemical microscopy, and cryogenic scanning transmission electron microscopy. The high-resolution imaging and real-time observations show that a loose, diffuse, and unevenly distributed SEI is formed during the initial dissolution process. This leads to the dramatically fast growth of Li during the subsequent deposition, deviating from Fick’s law, which exacerbates the interfacial impedance. The compactness of the interfacial structure and enrichment of electrolyte species at the surface during the initial deposition play critical roles in the long-term stability of Li anodes, as revealed by operando confocal Raman spectroscopic mapping. In conclusion, our observations relate to ion transfer, morphological and structural evolution, and Li (de)solvation at Li interfaces, revealing the underlying pathways influenced by the initial dissolution process, which promotes a reconsideration of anode investigations and effective protection strategies.

25 ENERGY STORAGE↗
DOE OSTI2025

Sulfide-Based Anode-Free Solid-State Batteries: Key Challenges and Emerging Solutions

Sulfide-based anode-free solid-state batteries (AFSSBs) have emerged as a transformative technology for next-generation energy storage, offering compelling advantages in energy density, safety, and manufacturing scalability. However, these batteries face significant challenges, particularly rapid capacity degradation that currently limits their practical implementation. This comprehensive review critically examines three fundamental issues affecting AFSSBs: nonuniform lithium nucleation on bare current collectors, unstable interfaces between plated lithium and sulfide electrolytes, and formation of interfacial voids during cycling. We systematically evaluate recent strategic advances in addressing these challenges, including metal seed coatings, conversion reaction-based compounds, and carbon-based interlayers. The review also analyzes the crucial role of advanced characterization techniques, from cryo-FIB-SEM to operando methods, in understanding failure mechanisms and validating improvement strategies. Finally, we present a forward-looking perspective on research directions necessary for commercialization. This work provides a thorough framework for understanding and advancing sulfide-based AFSSBs toward practical applications in next-generation energy storage systems.

25 ENERGY STORAGE↗
DOE OSTI2020

Direct Quantification of Heat Generation Due to Inelastic Scattering of Electrons Using a Nanocalorimeter

Transmission electron microscopy (TEM) is arguably the most important tool for atomic-scale material characterization. A significant portion of the energy of transmitted electrons is transferred to the material under study through inelastic scattering, causing inadvertent damage via ionization, radiolysis, and heating. In particular, heat generation complicates TEM observations as the local temperature can affect material properties. Here, the heat generation due to electron irradiation is quantified using both top-down and bottom-up approaches: direct temperature measurements using nanowatt calorimeters as well as the quantification of energy loss due to inelastic scattering events using electron energy loss spectroscopy. Combining both techniques, a microscopic model is developed for beam-induced heating and to identify the primary electron-to-heat conversion mechanism to be associated with valence electrons. Building on these results, the model provides guidelines to estimate temperature rise for general materials with reasonable accuracy. This study extends the ability to quantify thermal impact on materials down to the atomic scale.

42 ENGINEERING↗
NASA NTRS1985

Physical processes in prediction of explosive maritime cyclogenesis

Explosive maritime cyclogenetic events are usually aligned with the warm currents off the east coasts of Japan and the U.S. One such event occurred during FGGE in an area which featured good instrumented ship and aircraft coverage. The UCLA 4th order GMC was employed to generate predictions of the event for comparisons with the real-world data. FGGE III-b data were used to initialize the model calculations. Attention was directed to the physical processes causing the onset of the cyclogenesis, particularly the heat budgets of the fluxes involved. The diabatic heating was observed to be equivalent to the horizontal temperature advection. The main source of energy around the cyclone center was identified as the conversion of energy from static energy to kinetic energy. Further analyses of similar events are required if the present results are to be validated.

Liou, C.-S.↗
NASA NTRS2013

Constraints on Saturn's Tropospheric General Circulation from Cassini ISS Images

An automated cloud tracking algorithm is applied to Cassini Imaging Science Subsystem high-resolution apoapsis images of Saturn from 2005 and 2007 and moderate resolution images from 2011 and 2012 to define the near-global distribution of zonal winds and eddy momentum fluxes at the middle troposphere cloud level and in the upper troposphere haze. Improvements in the tracking algorithm combined with the greater feature contrast in the northern hemisphere during the approach to spring equinox allow for better rejection of erroneous wind vectors, a more objective assessment at any latitude of the quality of the mean zonal wind, and a population of winds comparable in size to that available for the much higher contrast atmosphere of Jupiter. Zonal winds at cloud level changed little between 2005 and 2007 at all latitudes sampled. Upper troposphere zonal winds derived from methane band images are approx. 10 m/s weaker than cloud level winds in the cores of eastward jets and approx. 5 m/s stronger on either side of the jet core, i.e., eastward jets appear to broaden with increasing altitude. In westward jet regions winds are approximately the same at both altitudes. Lateral eddy momentum fluxes are directed into eastward jet cores, including the strong equatorial jet, and away from westward jet cores and weaken with increasing altitude on the flanks of the eastward jets, consistent with the upward broadening of these jets. The conversion rate of eddy to mean zonal kinetic energy at the visible cloud level is larger in eastward jet regions (5.2x10(exp -5) sq m/s) and smaller in westward jet regions (1.6x10(exp -5) sqm/s) than the global mean value (4.1x10(ep -5) sq m/s). Overall the results are consistent with theories that suggest that the jets and the overturning meridional circulation at cloud level on Saturn are maintained at least in part by eddies due to instabilities of the large-scale flow near and/or below the cloud level.

DelGenio, Anthony D.↗
DOE OSTI2023

Electric charging particle heater for thermal energy storage

The disclosure relates to particle heaters for heating solid particles to store electrical energy as thermal energy. Thermal energy storage directly converts off-peak electricity into heat for thermal energy storage, which may be converted back to electricity, for example during peak-hour power generation. The particle heater is an integral part of an electro-thermal energy storage system, as it enables the conversion of electrical energy into thermal energy. As described herein, particle heater designs are described that provide efficient heating of solid particles in an efficient and compact configuration to achieve high energy density and low cost.

Ma, Zhiwen↗
DOE OSTI2021

Exogenous electricity flowing through cyanobacterial photosystem I drives CO 2 valorization with high energy efficiency

Nature's biocatalytic processes are driven by photosynthesis, whereby photosystems I and II are connected in series for light-stimulated generation of fuel products or electricity. Externally supplying electricity directly to the photosynthetic electron transfer chain (PETC) has numerous potential benefits, although strategies for achieving this goal have remained elusive. Here we report an integrated photo-electrochemical architecture which shuttles electrons directly to PETC in living cyanobacteria. The cathode of this architecture electrochemically interfaces with cyanobacterial cells that have a lack of photosystem II activity and cannot perform photosynthesis independently. Illumination of the cathode channels electrons from an external circuit to intracellular PETC through photosystem I, ultimately fueling cyanobacterial conversion of CO 2 into acetate. We observed acetate formation when supplying both illumination and exogenous electrons under intermittent conditions (e.g., in a 30 s supply plus 30 min interval condition of both light and exogenous electrons). The energy conversion efficiency for acetate production under programmed intermittent LED illumination (400–700 nm) and exogenous electron supply reached ca. 9%, when taking into account the number of photons and electrons received by the biotic system, and ca. 3% for total photons and electrons supplied to the cyanobacteria. This approach is applicable for generating various CO 2 reduction products by using engineered cyanobacteria, one of which has enabled electrophototrophic production of ethylene, a broadly used hydrocarbon in the chemical industry. The resulting bio-electrochemical hybrid has the potential to produce fuel chemicals with numerous potential advantages over standalone natural and artificial photosynthetic approaches.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1974

A study of the feasibility of directly applying gas generator systems to space shuttle mechanical functions

This study examined the current status and potential application of pyrotechnic gas generators and energy convertors for the space shuttle program. While most pyrotechnic devices utilize some form of linear actuation, only limited use of rotary actuators has been observed. This latter form of energy conversion, using a vane-type actuator as optimum, offers considerable potential in the area of servo, as well as non-servo systems, and capitalizes on a means of providing prolonged operating times. Pyrotechnic devices can often be shown to provide the optimum means of attaining a truly redundant back-up to a primary, non-pyrotechnic system.

Lake, E. R.↗
DOE OSTI2023

Intensified Catalytic Conversion of CO2 into High Value Chemicals

The utilization of CO2 produced from power generation plants as a feedstock for creating new valuable products offers a strategy to reduce GHG emissions, offset carbon capture costs, and facilitate the rebalancing of the carbon cycle. After considering the thermodynamic requirement of potential products from CO2 utilization and their market size, formic acid is a desirable target that offers widespread utility in industrial chemical production and chemical energy storage as a liquid fuel. To effectively utilize CO2 from power generation plants, UK proposes an enhanced bimetallic oxide carbon utilization process (EBOCU) that enables electrochemical CO2 conversion to formic acid. The UK intensified electrocatalytic process combines three main components: 1) a novel bimetallic oxide electrocatalyst; 2) a stable electrochemical reactor using robust electrodes; and 3) a pressurized electrochemical reactor. The output from this project showed the economic viability of producing high-value formic acid from CO2 to both offset the cost associated with post-combustion CCS and reduce GHG emissions. This project developed and screened a series engineered catalysts to selectively reduce CO2 directly to formic acid. The best performing catalyst based on formic acid production, stability, and Faradaic efficiency, was immobilized on carbon electrodes, and tested inside a flow through reactor. After lab-scale testing was completed, the experimental data was used to perform a Life-Cycle Analysis (LCA) and conduct an Initial Technical and Economic Feasibility Study. The LCA showed a pathway to a net negative CO2 utilization process with the incorporation of renewable energy, while the TEA showed the potential to produce formic acid below the current commercial price. The UK EBOCU process was successfully demonstrated at the TRL3 level and has a clear pathway to further development and contribution to the nation’s ambitious decarbonization goals.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2023

Climate cooling benefits of cellulosic bioenergy crops from elevated albedo

Abstract Changes in land surface albedo can alter ecosystem energy balance and potentially influence climate. We examined the albedo of six bioenergy cropping systems in southwest Michigan USA: monocultures of energy sorghum ( Sorghum bicolor ), switchgrass ( Panicum virgatum L.), and giant miscanthus ( Miscanthus × giganteus) , and polycultures of native grasses, early successional vegetation, and restored prairie. Direct field measurements of surface albedo ( α s ) from May 2018 through December 2020 at half‐hourly intervals in each system quantified the magnitudes and seasonal differences in albedo (∆ α ) and albedo‐induced radiative forcing (RF ∆ α ). We used a nearby forest as a historical native cover type to estimate reference albedo and RF ∆ α change upon original land use conversion, and a continuous no‐till maize ( Zea mays L .) system as a contemporary reference to estimate change upon conversion from annual row crops. Annually, α s differed significantly ( p < 0.05) among crops in the order: early successional (0.288 ± 0.012SE) >> miscanthus (0.271 ± 0.009) ≈ energy sorghum (0.270 ± 0.010) ≥ switchgrass (0.265 ± 0.009) ≈ restored prairie (0.264 ± 0.012) > native grasses (0.259 ± 0.010) > maize (0.247 ± 0.010). Reference forest had the lowest annual α s (0.134 ± 0.003). Albedo differences among crops during the growing season were also statistically significant, with growing season α s in perennial crops and energy sorghum on average ~20% higher (0.206 ± 0.003) than in no‐till maize (0.184 ± 0.002). Average non‐growing season (NGS) α s (0.370 ± 0.020) was much higher than growing season α s (0.203 ± 0.003) but these NGS differences were not significant. Overall, the original conversion of reference forest and maize landscapes to perennials provided a cooling effect on the local climate (RF αMAIZE : −3.83 ± 1.00 W m −2 ; RF αFOREST : −16.75 ± 3.01 W m −2 ). Significant differences among cropping systems suggest an additional management intervention for maximizing the positive climate benefit of bioenergy crops, with cellulosic crops on average ~9.1% more reflective than no‐till maize, which itself was about twice as reflective as the reference forest.

Lei, Cheyenne↗
DOE OSTI2025

Challenges and strategies for probing the composite interface of PEM electrolyzers and fuel cells using operando AP-XPS

Left: cross-section schematic of a membrane electrode assembly, the working electrode changing state with applied potential. Center: the operando cell design that enables snapshot data acquisition during trajectory movement. Right: resulting spectra. Understanding the surface chemistry of electrocatalyst systems under operando conditions is central to revealing the electrocatalytic cell's working mechanisms. Determination of these catalytic processes on a molecular scale and the involved components is fundamental to streamlining material design for energy conversion and storage applications. X-ray photoelectron spectroscopy (XPS) is an established technique used to study the chemical and electronic states of materials. While the surface sensitivity of XPS is typically high, use of tender X-ray energies and technical advancements have allowed for the direct probing of solid–vapor and solid–liquid interfaces. However, protocols and documentation of experimental considerations for operando XPS probing of working electrolyzers and fuel cells remain scarce. Herein, we report an approach for the study of working polymer electrolyte membrane (PEM) electrolysis cells using ambient pressure X-ray photoelectron spectroscopy (AP-XPS). This approach directly probes the composite electrode surface on the membrane electrode assembly (MEA) in 100% relative humidity to establish a meaningful liquid layer for electrocatalysis. We carry out a systematic investigation from the cell constituent components to a fully assembled working operando electrolytic system and establish a method for AP-XPS study of the complex composite MEA, providing recommendations for data acquisition and component analysis.

Hamlyn, Rebecca↗