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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

De novo protein design of photochemical reaction centers

Abstract Natural photosynthetic protein complexes capture sunlight to power the energetic catalysis that supports life on Earth. Yet these natural protein structures carry an evolutionary legacy of complexity and fragility that encumbers protein reengineering efforts and obfuscates the underlying design rules for light-driven charge separation. De novo development of a simplified photosynthetic reaction center protein can clarify practical engineering principles needed to build new enzymes for efficient solar-to-fuel energy conversion. Here, we report the rational design, X-ray crystal structure, and electron transfer activity of a multi-cofactor protein that incorporates essential elements of photosynthetic reaction centers. This highly stable, modular artificial protein framework can be reconstituted in vitro with interchangeable redox centers for nanometer-scale photochemical charge separation. Transient absorption spectroscopy demonstrates Photosystem II-like tyrosine and metal cluster oxidation, and we measure charge separation lifetimes exceeding 100 ms, ideal for light-activated catalysis. This de novo-designed reaction center builds upon engineering guidelines established for charge separation in earlier synthetic photochemical triads and modified natural proteins, and it shows how synthetic biology may lead to a new generation of genetically encoded, light-powered catalysts for solar fuel production.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

A recirculation system for concentrating CO 2 electrolyzer products

Electrochemical carbon dioxide reduction represents a promising path to utilize CO 2 as a feedstock for generating valuable products such as fuels and chemicals. Faradaic efficiencies near 100% have been achieved for certain CO 2 reduction products such as CO, but the electrolyzer outlet streams usually contain large fractions of unreacted CO 2 , dropping the product concentrations below 1% in many cases. The system disclosed here recycles the unreacted CO 2 together with the products and flows them back into the CO 2 reduction reactor, enabling much higher CO 2 conversion rates without dropping the gas flow rate. However, simple recirculation is shown to accumulate significant amounts of hydrogen, impeding effective CO 2 reduction. In this looped system, an electrochemical H 2 pump is placed in series with the CO 2 reactor, which effectively removes all the H 2 from the recycled gas stream, increasing the concentrations of carbon-containing products. Here, the system was initially tested with a CO-generating catalyst and CO concentrations above 70% were achieved in the recycled gas stream, compared to a maximum CO concentration of 8% in single-pass configuration. Results with a CO 2 reactor targeting ethylene as the main product show that ethylene concentrations of at least 10% can be achieved, which is roughly 20 times higher compared to a single-pass system.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Informing the planning of rotating power outages in heat waves through data analytics of connected smart thermostats for residential buildings

Abstract With climate change, heat waves have become more frequent and intense. Rotating power outages happen when the power supply is unable to meet the cooling demand increase resulting from extreme high temperatures. Power outages during heat waves expose residents to high risks of overheating. In this study, we propose a novel data-driven inverse modelling approach to inform decision makers and grid operators on planning rotating power outages. We first infer the building thermal characteristics using the connected smart thermostat data, and used the estimated thermal dynamics to simulate the thermal resilience during a heat wave event. Our proposed method was tested for the California power outage in August 2020 by using the open source Ecobee Donate Your Data dataset. We found in California the power outage should not last more than two hours during heat waves to avoid overheating risks. Informing the residents in advance so they can prepare for it through pre-cooling is a simple but effective strategy to expand the acceptable power outage duration. In addition to assisting power outage planning, the proposed method can be used for other applications, such as to evaluate a building energy efficiency policy, to examine fuel poverty, and to estimate the load shifting potential of building stocks.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2025

Development of an atomic layer deposition system for deposition of alumina as a hydrogen permeation barrier

Tritium permeation into and through materials poses a critical challenge for the development of nuclear fusion reactors. Minimizing tritium permeation is essential for the safe and efficient use of available fuel supplies. In this work, we present the design, construction, and validation of custom atomic layer deposition (ALD) and deuterium permeation measurement systems aimed at developing thin-film hydrogen permeation barriers. Using the ALD system, we deposited conformal $\mathrm{Al}_{2}\mathrm{O}_{3}$ films on copper foil substrates and characterized their growth behavior, morphology, and composition. ALD growth rates of ∼1.1 Å/cycle were achieved for temperatures between 100 ∘ C and 210 ∘ C. Permeation measurements on bare and alumina coated copper foils revealed a significant reduction in deuterium flux with the addition of a ∼10 nm $\mathrm{Al}_{2}\mathrm{O}_{3}$ layer. While bare copper followed diffusion-limited transport consistent with Sievert’s law, the alumina-coated samples exhibited surface-limited, pore-mediated transport with linear pressure dependence. Arrhenius analysis showed distinct differences in activation energy for the two transport regimes, and permeation reduction factors exceeding an order of magnitude were observed. These results demonstrate the potential of ALD-grown $\mathrm{Al}_{2}\mathrm{O}_{3}$ films as effective hydrogen isotope barriers and provide a foundation for future studies on film optimization and integration into fusion-relevant components.

atomic layer deposition↗
DOE OSTI2021

Effect of Catalyst and Catalyst Layer Composition on Catalyst Support Durability

Polymer electrolyte membrane fuel cells (PEMFCs) are efficient, zero-emission engines for the automotive sector. However, cost and durability are major barriers for the commercialization of PEMFCs. Degradation of the carbon support in the cathode catalyst layer due to high potential excursions caused by unmitigated events like H 2 starvation, or start-up/shutdown are still a major durability issue in PEMFCs. Catalyst support durability was studied by accelerated stress tests (ASTs) that included repeated potential cycling from 1.0 to 1.5 V. The effect of catalyst layer composition on carbon corrosion was studied using membrane electrode assemblies with different catalysts (Pt, PtCo), catalyst composition (catalyst wt.%, supports), ionomer composition (loading, and equivalent weights). The corrosion of the carbon support is similar between Pt and PtCo catalysts. However, the performance degradation rate is higher for the alloy catalysts due to differences in catalyst particle size and the transition metal’s leaching accelerating the performance degradation. The carbon loss is lower for catalysts with lower initial carbon loading (or higher catalyst wt.%), which is better for durability. However, the cumulative loss of carbon is identical for electrodes with the same catalyst support irrespective of catalyst and ionomer composition in the catalyst layer.

25 ENERGY STORAGE↗
DOE OSTI2023

Knock-limited combustion of ethanol-, isobutanol-, and 2-methyl-3-buten-2-ol-gasoline blends in a direct-injected spark-ignition engine

Knock-limited combustion of alcohol-gasoline fuel blends was studied in a direct-injection spark-ignition engine. Ethanol, isobutanol (2-methyl-1-propanol), and methylbutenol (2-methyl-3-buten-2-ol) were splash-blended with a blendstock for oxygenate blending (BOB) gasoline. Ethanol was blended in fractions of 10%, 20%, and 30% by volume (E10, E20, and E30). Isobutanol and methylbutenol were blended to match the oxygen weight percentage of the ethanol blends, resulting in blends of 16%, 32%, and 49% (I16, I32, and I49) isobutanol by volume and 18%, 37%, and 56% (M18, M37, and M56) methylbutenol by volume. Neat BOB and gasoline primary reference fuels (PRF) with octane numbers (ON) of 87 (PRF87) and 100 (PRF100) were included for reference. The engine was operated at fixed speed, equivalence ratio, and injection timing while knock-limited spark advance was located across a range of intake pressures. Low-level alcohol blends E10 and M18 had similar knocking behavior and appeared to be slightly more knock-resistant than I16. For mid-level blends, E20 showed further improvement over I32 while M37 showed noticeably better knock resistance, able to match the knock-resistance of PRF100 for loads above 1000 kPa gross indicated mean effective pressure (GIMEP). For high-level blends, the difference between E30 and I49 was similar to their mid-level counterparts. However, M56 showed significant improvement over E30 and I49 throughout the entire range of loads tested. M56 exceeded the knock-resistance of PRF100 for loads above 700 kPa GIMEP. The improved knock-resistance combined with the increased volumetric energy density of methylbutenol resulted in improved fuel consumption and indicated efficiency. The overall results of this study indicate that the order of knock-resistance of these three alcohols, for direct-injection operation with injection during the intake stroke, is isobutanol < ethanol < methylbutenol when compared on an equal oxygen weight basis.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

FY 2019 DOE-EERE Materials Vehicle Technologies Office Consolidated Report

The Materials Technology Program supports the Vehicle Technologies Office’s mission to help consumers and businesses reduce their transportation energy costs while meeting or exceeding vehicle performance expectations. The propulsion materials research portfolio seeks to develop higher performance materials that can withstand increasingly extreme environments and address the future properties needed for a variety of high-efficiency powertrain types, sizes, fueling concepts, and combustion modes. The lightweight materials research portfolio enables improvements in fuel economy by providing properties that are equal to or better than traditional materials at a lower weight. Because it takes less energy to accelerate a lighter object, replacing cast-iron and traditional steel components with lightweight materials such as advanced high-strength steels, magnesium alloys, aluminum alloys, and fiber-reinforced polymer composites can directly reduce a vehicle’s fuel consumption. By 2025, Materials Technology research activities seek to enable a 25% weight reduction of the glider for light-duty vehicles including body, chassis, and interior as compared to a 2015 baseline at no more than a $5/lb-saved increase in cost.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2020

FY2019 Materials Annual Progress Report

The Materials Technology Program supports the Vehicle Technologies Office’s (VTO’s) mission to help consumers and businesses reduce their transportation energy costs while meeting or exceeding vehicle performance expectations. The propulsion materials research portfolio seeks to develop higher performance materials that can withstand increasingly extreme environments and address the future properties needed for a variety of high-efficiency powertrain types, sizes, fueling concepts, and combustion modes. The lightweight materials research portfolio enables improvements in fuel economy by providing properties that are equal to or better than traditional materials at a lower weight. Because it takes less energy to accelerate a lighter object, replacing cast-iron and traditional steel components with lightweight materials such as advanced high-strength steels, magnesium (Mg) alloys, aluminum (Al) alloys, and fiber-reinforced polymer composites can directly reduce a vehicle’s fuel consumption. By 2025, Materials Technology research activities seek to enable a 25% weight reduction of the glider for light-duty (LD) vehicles including body, chassis, and interior as compared to a 2015 baseline at no more than a $5/lb-saved increase in cost.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2021

FY2020 Materials Annual Progress Report

The Materials Technology subprogram supports the Vehicle Technologies Office’s (VTO’s) mission to accelerate the deployment of clean energy technology toward achieving net-zero emissions in the transportation sector. The Propulsion Materials research portfolio seeks to develop higher performance materials that can withstand increasingly extreme environments and address the future properties needed for a variety of high-efficiency powertrain types, sizes, fueling concepts, and combustion modes. The Lightweight Materials research portfolio enables improvements in fuel economy by providing properties that are equal to or better than traditional materials at a lower weight. Because it takes less energy to accelerate a lighter object, replacing cast-iron (Fe) and traditional steel components with lightweight materials—such as advanced high-strength steels (AHSS), magnesium (Mg) alloys, aluminum (Al) alloys, and fiber-reinforced polymer composites—can directly reduce a vehicle’s fuel consumption. By 2025, the Materials Technology research activities seek to enable a 25% weight reduction of the glider for light-duty (LD) vehicles including body, chassis, and interior as compared to a 2015 baseline at no more than a $5/lb-saved increase in cost.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2022

OPEN2018 (continuation of GENSETS effort)

This project has demonstrated the key components and engineering principles to support a residential scale (1 to 2 kWe) recuperated Brayton cycle generator based upon a screw compressor and screw expander. This technical work is a continuation of the previously awarded ‘GENSETS’ program. The product goal has been to achieve a 40% fuel-to-electric LHV efficiency, an 80% overall CHP efficiency, emissions qualified to the California Air Resources Board standards, and at noise levels of 55 dB or less at 1 meter. Further, the product must operate with 8,000 hour service intervals and achieve a mean-time to overhaul of 90,000 hours. Lastly, and possibly most importantly, the product must meet demanding cost targets, exhibiting a factory cost well below $1,500/kWe. After extensive aerodynamic studies under the ‘GENSETS’ program, Brayton concluded that miniature turbomachinery could not achieve an efficiency consistent with the product’s system performance goal. Given compressor and turbine efficiency targets in the range of 78 to 81%, Brayton turned to the rotary screw machines. While the justification for a screw compressor over a conventional centrifugal compressor is well supported by industry experience, the high temperature expander represented the core technology advancement. To meet the extremely high efficiency goals, an all-ceramic rotary screw expander hot section was developed and has now been tested in the laboratory. This first-of-its-kind ceramic screw expander prototype was able to demonstrate aerodynamic efficiency in line with predictions. The test article was successfully run to full stress conditions so has also validated the mechanical design of such a unit. This has opened new avenues for the commercialization of high efficiency, small scale power generation. Interest in the technology has sparked several requests for alternate uses, an invitation to present at a screw machine conference, and continued interest from parties looking to develop a product in the spirit of the original ‘GENSETS’ goals.

42 ENGINEERING↗
DOE OSTI2024

Inaugural Symposium of the Institute for Sustainable Energy and Environment, Virginia Commonwealth University

The Inaugural Symposium of the Institute for Sustainable Energy and Environment (ISEE) was held in Virginia Commonwealth University, Richmond, Virginia during April 26 – 28, 2023. The symposium addressed issues and challenges in energy and environment and highlighted the use of clean renewable energy to mitigate the adverse effects of fossil fuels and the greenhouse gases it produces. These issues are complex as the involve educating the public that the climate change is real, it is caused by the use of fossil fuels, it requires scientists and engineers to understand the fundamental science in the production and storage of renewable energy, it requires industries to manufacture and distribute the equipment necessary for commercial application of these technologies, it requires policy makers to put together policies and guidelines to make the transition from fossil fuels to renewable energies efficient, and it requires social scientists and educators to address environmental justice issues and create a workforce to sustain the transition. The symposium considered all the above issues with a diverse list of speakers from the federal and state government, industrial partners, and experts from science and technology to social sciences and public policy. Speakers from the White House Office of Science and Technology Policy, Department of Energy, universities, and non-governmental agencies discussed the challenges and solutions in Plenary as well as Panel sessions. The talks were recorded with permission from the speakers and the panelists and were put in the ISEE website. The participants included students, postdoctoral fellows, and professors from Virginia Commonwealth University and local area Historically Black College and Universities (HBCU) such as Virginia State University and Norfolk State University. The $5000 fund awarded by the Department of Energy were used to support the participation of students, postdoctoral fellows, and faculty from the HBCU institutions. The technical program the list of participants is provided later in the document.

08 HYDROGEN↗
DOE OSTI2024

Design and Evaluation of Environmental Barrier Coatings for Protection of Ceramic Matrix Composites in Hydrogen-Based Turbines

This presentation at the 2024 FECM Spring Project Review Meeting summarizes ongoing work at NETL aimed at enabling the use of ceramic matrix composite (CMC) materials in next-generation high-efficiency power generation turbines fueled by hydrogen, natural gas, or other fuels. The work broadly involves three aspects (1) phase-field damage modeling of CMCs and the environmental barrier coatings (EBCs) used to protect them (2) computational design of new and improved EBCs and (3) performance testing of EBCs using a novel gas turbine combustion simulation rig developed at NETL. An overview on current status and next steps for each aspect of the project are presented.

ceramic matrix composite (CMC)↗
DOE OSTI2025

Estimating Switchgrass Biomass Yield and Lignocellulose Composition from UAV-Based Indices

Innovative methods for estimating commercial-scale switchgrass yields and feedstock quality are essential to optimize harvest logistics and biorefinery efficiency for sustainable aviation fuel production. This study utilized vegetation indices (VIs) derived from multispectral images to predict biomass yield and lignocellulose concentrations of advanced bioenergy-type switchgrass cultivars (“Liberty” and “Independence”) under two N rates (28 and 56 kg N ha –1 ). Field-scale plots were arranged in a randomized complete block design (RCBD) and replicated three times at Urbana, IL. Multispectral images captured during the 2021–2023 growing seasons were used to extract VIs. The results show that linear and exponential models outperformed partial least square and random forest models, with mid-August imagery providing the best predictions for biomass, cellulose, and hemicellulose. The green normalized difference vegetation index (GNDVI) was the best univariate predictor for biomass yield (R 2 = 0.86), while a multivariate combination of the GNDVI and normalized difference red-edge index (NDRE) enhanced prediction accuracy (R 2 = 0.88). Cellulose was best predicted using the NDRE (R 2 = 0.53), whereas hemicellulose prediction was most effective with a multivariate model combining the GNDVI, NDRE, NDVI, and green ratio vegetation index (GRVI) (R 2 = 0.44). These findings demonstrate the potential of UAV-based VIs for the in-season estimation of biomass yield and cellulose concentration.

09 BIOMASS FUELS↗
DOE OSTI2024

Light Duty Engine Performance Characteristics with Dimethyl Ether and Propane

Here, this paper explores the performance characteristics of a compression ignition HYUNDAI 2.2L engine operating with Dimethyl Ether (DME). Test are carried out at three operating conditions that weigh heavily in the FTP75 certification cycle (1000rpm-12Nm, 1500rpm-50Nm, 2000rpm-100Nm). The engine features a high-pressure common rail fuel injection system designed to operate with liquified gases. The main component of the fuel system is a high-pressure pump that incorporates an electronic inlet metering valve commanded on a crank-angle base to control the rail pressure. The pump, which requires no pressure regulator, provides the flow needed to the injectors without flow returning to the inlet. This novel fueling system is leveraged in tests that are conducted to examine the impact of EGR, combustion phasing, injection pressure on efficiency and emissions. In addition, the impact of introducing 15% Propane by mass is examined. During the tests, the engine ECU is aided by an Engine Controller High Speed Oversight unit (ECHO) to provide combustion phasing control, improved cylinder-to-cylinder uniformity, and an effective optimization over the testing effort. The use of DME and Propane allowed for peak thermal efficiency of nearly 43%. These fuels enable significant carbon index (CI) reductions over the baseline Diesel fuel, with indications that 50% reduction in CO 2 over the Diesel engine are possible.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2022

Techno-Economic Evaluation of Strategies to Approach Net-Zero Carbon Sustainable Aviation Fuel via Woody Biomass Gasification and Fischer-Tropsch Synthesis

Reducing the carbon dioxide (CO2) emissions from the transportation industry is a key target for achieving global net-zero carbon goals. Wide-spread electrification, efficient engine design, and alternative fuel implementations have been introduced for light-duty vehicles and are projected to significantly reduce light-duty emissions in the near future. Conversely, the aviation sector contributes considerably towards transportation-based carbon emissions, but current projections do not show substantial reductions in carbon emissions over time. Challenges for the aviation sector include low compatibility with electrification, relative inflexibility to variations in fuel properties, and requirement of high energy density fuels. Thus, identifying pathways to decarbonize the aviation sector via liquid low- or net-zero carbon biofuels that are compatible with current aviation infrastructure is crucial. This work investigates the economic feasibility of approaching net-zero carbon sustainable aviation fuel (SAF) from woody biomass via gasification and Fischer-Tropsch synthesis. In doing so, this assessment identifies the economic opportunities and trade-offs of several carbon mitigation strategies coupled with renewable resource interventions required to approach net-zero carbon fuels via biomass. Renewable natural gas and green hydrogen utilization strategies are assessed to examine the impact of fuel yield improvements versus renewable resource cost. Additionally, both carbon capture and sequestration (CCS) and carbon capture and utilization (CCU) are considered in this analysis to help mitigate carbon loss to the atmosphere. Each scenario was assessed on cost, carbon efficiency, energy efficiency, and overall technology-readiness level (TRL). The results of this analysis show that renewable natural gas, green hydrogen, and CCS can be viewed as a low-cost, near-term carbon abatement strategies. However, in the long-term, deployment of more expensive and less technologically mature CCU technologies can make use of point sources of CO2 to boost overall fuel production.

aviation fuel↗
DOE OSTI2020

MSR Fuel Salt Qualification Methodology

This report documents the continuing activities at Oak Ridge National Laboratory (ORNL) in support of the US Nuclear Regulatory Commission (NRC) efforts to develop an efficient, appropriate process for liquid fuel salt system qualification. Fuel qualification for salt-cooled molten salt reactors (MSRs) is part of the ongoing coated particle fuel qualification effort. Fuel qualification is a process which provides high confidence that physical and chemical behavior of fuel is sufficiently understood so that it can be adequately modeled for both normal and accident conditions, reflecting the role of the fuel design in the overall safety of the facility. Uncertainties are defined so that calculated fission product releases include the appropriate margins to ensure conservative calculation of radiological dose consequences. The initial phase of ORNL’s activities is documented in ORNL/LTR-2018/1045 Molten Salt Reactor Fuel Qualification Considerations and Challenges.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Fuel Effects on Advanced Compression Ignition Load Limits

In order to increase the efficiency of light-duty gasoline engines, the Co-Optimization of Fuels and Engines (Co-Optima) initiative from the U.S. Department of Energy is investigating multi-mode combustion strategies. Multi-mode combustion can be describe as using conventional spark-ignited combustion at high loads, and at the part-load operating conditions, various advanced compression ignition (ACI) strategies are being investigated to increase efficiency. Of particular interest to the Co-Optima initiative is the extent to which optimal fuel properties and compositions can enable higher efficiency ACI combustion over larger portions of the operating map. Extending the speed-load range of these ACI modes can enable greater part-load efficiency improvements for multi-mode combustion strategies. In this manuscript, we investigate fuel effects for six different fuels, including four with a research octane number (RON) of 98 and differing fuel chemistries, iso-octane, and a market representative E10 fuel, on the load limits for two different ACI strategies: spark-assisted compression ignition (SACI) and partial fuel stratification-gasoline compression ignition (PFS-GCI) operation. Experimental results show that limits to intake boosting limit high load operation for most fuels, but high smoke emissions for high particulate matter index (PMI) fuels under SACI conditions could also be a limitation. Contrastingly, low load is limited by combustion efficiency, but these effects have more pronounced variation with fuel chemistry for PFS-GCI than with SACI. Additional, distinct effects affecting autoignition timing and peak heat release at higher speeds were identified for fuels having different low temperature heat release (LTHR) propensities for both ACI modes.

33 ADVANCED PROPULSION SYSTEMS↗