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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 1,117 records · Page 62
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Photoelectrochemical CO 2 Reduction toward Multicarbon Products with Silicon Nanowire Photocathodes Interfaced with Copper Nanoparticles

The development of photoelectrochemical systems for converting CO 2 into chemical feedstocks offers an attractive strategy for clean energy storage by directly utilizing solar energy, but selectivity and stability for these systems have thus been limited. Here, we interface silicon nanowire (SiNW) photocathodes with a copper nanoparticle (CuNP) ensemble to drive efficient photoelectrochemical CO 2 conversion to multicarbon products. This integrated system enables CO 2 -to-C 2 H 4 conversion with faradaic efficiency approaching 25% and partial current densities above 2.5 mA/cm 2 at -0.50 V vs RHE, while the nanowire photocathodes deliver 350 mV of photovoltage under 1 sun illumination. Under 50 h of continual bias and illumination, CuNP/SiNW can sustain stable photoelectrochemical CO 2 reduction. In conclusion, these results demonstrate the nanowire/catalyst system as a powerful modular platform to achieve stable photoelectrochemical CO 2 reduction and the feasibility to facilitate complex reactions toward multicarbons using generated photocarriers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

An Assessment of Deploying Advanced Pumped Storage Hydropower Technology in U.S. Electricity Markets

Pumped storage hydropower (PSH) is a type of hydropower technology where energy can be stored and generated by moving water between two reservoirs of differing elevations. In addition to providing 97% of the total utility-scale hydropower storage in the United States, PSH plants have operational characteristics - such as high ramp rates and the ability to provide reserves - that contribute to greater flexibility and reliability of the power grid. New PSH technologies can provide additional flexibility beyond existing, fixed-speed units. With the emergence of high levels of variable renewable energy resources (e.g., wind and solar), energy storage is expected to be crucial to the reliability and reliance of the power grid in a low-carbon future. At diurnal and longer durations, PSH plants have some of the lowest costs per unit of energy, have been proven to be reliable and efficient, are not cycle-limited, and typically have long lives, often exceeding 50 years. The work presented here focuses on a new generation of PSH: ternary PSH and quaternary PSH (together referred to as T/Q-PSH). Given recent experience in Europe, grid operators in the United States and elsewhere are increasingly focusing their attention on T/Q-PSH as a proven, financeable technology that can offer utility-scale, long-duration, fast-acting energy storage capabilities and grid services. T/Q-PSH differs from conventional PSH in that it can provide fast-response ancillary services during both generating and pumping operations. This capability together with fast mode switching times are key attributes that make T/Q-PSH technologies attractive for managing and stabilizing electricity systems with high amounts of variable renewable energy.

ENERGY PLANNING, POLICY, AND ECONOMY,HYDRO ENERGY↗
NASA NTRS1974

Possibility of using sources of vacuum ultraviolet irradiation to solve problems of space material science

An urgent problem in space materials science is simulating the interaction of vacuum ultraviolet (VUV) of solar emission with solids in space conditions, that is, producing a light source with a distribution that approximates the distribution of solar energy. Information is presented on the distribution of the energy flux of VUV of solar radiation. Requirements that must be satisfied by the VUV source used for space materials science are formulated, and a critical evaluation is given of the possibilities of using existing sources for space materials science. From this evaluation it was established that none of the sources of VUV satisfies the specific requirements imposed on the simulator of solar radiation. A solution to the problem was found to be in the development of a new type of source based on exciting a supersonic gas jet flowing into vacuum with a sense electron beam. A description of this gas-jet source, along with its spectral and operation characteristics, is presented.

Verkhoutseva, E. T.↗
NASA NTRS1978

SIMS prototype system 1 test results: Engineering analysis

The space and domestic water solar heating system designated SIMS Prototype Systems 1 was evaluated. The test system used 720 ft (gross) of Solar Energy Products Air Collectors, a Solar Control Corporation SAM 20 Air Handler with Model 75-175 control unit, a Jackson Solar Storage tank with Rho Sigma Mod 106 controller, and 20 tons of rack storage. The test data analysis performed evaluates the system performance and documents the suitability of SIMS Prototype System 1 hardware for field installation.

Source record↗
NASA NTRS1980

Installation package for a solar-heating system

Package consists of installation, operation and maintenance manuals for four commercial solar energy subsystems, including flat plate solar collector pebble bed thermal-storage. Manual gives design information, sizing data, specification drawings, and other material for subsystem.

Source record↗
NASA NTRS1995

Design of a GaAs/Ge Solar Array for Unmanned Aerial Vehicles

Unmanned Aerial Vehicles (UAV) are being proposed for many applications including surveillance, mapping and atmospheric studies. These applications require a lightweight, low speed, medium to long duration airplane. Due to the weight, speed, and altitude constraints imposed on such aircraft, solar array generated electric power is a viable alternative to air-breathing engines. Development of such aircraft is currently being funded under the Environmental Research Aircraft and Sensor Technology (ERAST) program. NASA Lewis Research Center (LeRC) is currently building a Solar Electric Airplane to demonstrate UAV technology. This aircraft utilizes high efficiency Applied Solar Energy Corporation (ASEC) GaAs/Ge space solar cells. The cells have been provided by the Air Force through the ManTech Office. Expected completion of the plane is early 1995, with the airplane currently undergoing flight testing using battery power.

Scheiman, David A.↗
NASA NTRS1998

GaAs/Ge Solar Powered Aircraft

Unmanned Aerial Vehicles (UAV) are being proposed for many applications for many applications including surveillance, mapping and atmospheric studies. These applications require a lightweight, low speed, medium to long duration aircraft. Due to the weight, speed, and altitude constraints imposed on such an aircraft, solar array generated electric power can be a viable alternative to air-breathing engines for certain missions. Development of such an aircraft is currently being funded under the Environmental Research Aircraft and Sensor Technology (ERAST) program. NASA Lewis Research Center (LeRC) has built a Solar Electric Airplane to demonstrate UAV technology. This aircraft utilizes high efficiency Applied Solar Energy Corporation (ASEC) GaAs/Ge space solar cells. The cells have been provided by the Air Force through the ManTech Office.

Colozza, Anthony J.↗
NASA NTRS2002

A Remote Sensing Approach for Urban Environmental Decision-Making: An Atlanta, Georgia Case Study

Unquestionably, urbanization causes tremendous changes in land cover and land use, as well as impacting a host of environmental characteristics. For example, unlike natural surfaces, urban surfaces have very different thermal energy properties whereby they store solar energy throughout the day and continue to release it as heat well after sunset. This effect, known as the 'Urban Heat Island', serves as a catalyst for chemical reactions from vehicular exhaust and industrial activities leading to the deterioration in air quality, especially exacerbating the production of ground level ozone. 'Cool Community' strategies that utilize remote sensing data, are now being implemented as a way to reduce the impacts of the urban heat island and its subsequent environmental impacts. This presentation focuses on how remote sensing data have been used to provide descriptive and quantitative data for characterizing the Atlanta, Georgia metropolitan area - particularly for measuring surface energy fluxes, such as the thermal or "heat" energy that emanates from different land cover types across the Atlanta urban landscape. In turn, this information is useful for developing a better understanding of how the thermal characteristics of the city surface affect the urban heat island phenomena and, ultimately, air quality and other environmental parameters over the Atlanta metropolitan region. Additionally, this paper also provides insight on how remote sensing, with its synoptic approach, can be used to provide urban planners, local, state, and federal government officials, and other decision-makers, as well as the general public, with information to better manage urban areas as sustainable environments.

Quattrochi, Dale A.↗
NASA NTRS2002

Powering the Future

Stirling Technology Company (STC) developed the RG-350 convertor using components from separate Goddard Space Center and U.S. Army Natick SBIR contracts. Based on the RG-350, STC commercialized a product line of Stirling cycle generator sets, known as RemoteGen(TM), with power levels ranging from 10We to 3kWe. Under SBIR agreements with Glenn Research Center, the company refined and extended the capabilities of the RemoteGen convertors. They can provide power in remote locations by efficiently producing electricity from multiple-fuel sources, such as propane, alcohol, gasoline, diesel, coal, solar energy, or wood pellets. Utilizing any fuel source that can create heat, RemoteGen enables the choice of the most appropriate fuel source available. The engines operate without friction, wear, or maintenance. These abilities pave the way for self-powered appliances, such as refrigerators and furnaces. Numerous applications for RemoteGen include quiet, pollution-free generators for RVs and yachts, power for cell phone towers remote from the grid, and off-grid residential power variously using propane, ethanol, and solid biomass fuels. One utility and the National Renewable Energy Laboratory are evaluating a solar dish concentrator version with excellent potential for powering remote irrigation pumps.

Source record↗
NASA NTRS1998

Refractive Secondary Solar Concentrator Being Designed and Developed

As the need for achieving super high temperatures (2000 K and above) in solar heat receivers has developed so has the need for secondary concentrators. These concentrators refocus the already highly concentrated solar energy provided by a primary solar collector, thereby significantly reducing the light entrance aperture of the heat receiver and the resulting infrared radiation heat loss from the receiver cavity. Although a significant amount of research and development has been done on nonimaging hollow reflective concentrators, there has been no other research or development to date on solid, single crystal, refractive concentrators that can operate at temperatures above 2000 K. The NASA Lewis Research Center recently initiated the development of single-crystal, optically clear, refractive secondary concentrators that, combined with a flux extractor, offer a number of significant advantages over the more conventional, hollow, reflective concentrators at elevated temperatures. Such concentrators could potentially provide higher throughput (efficiency), require no special cooling device, block heat receiver material boiloff from the receiver cavity, provide for flux tailoring in the cavity via the extractor, and potentially reduce infrared heat loss via an infrared block coating.The many technical challenges of designing and fabricating high-temperature refractive secondary concentrators and flux extractors include identifying optical materials that can survive the environment (high-temperature, vacuum and/or hydrogen atmosphere), developing coatings for enhanced optical and thermal performance, and developing crystal joining techniques and hardware that can survive launch loads.

Macosko, Robert P.↗
NASA NTRS1999

Inflatable Solar Thermal Concentrator Delivered

Space-based solar thermal power systems are very appealing as a space power source because they generate power efficiently. However, solar thermal (dynamic) systems currently incorporate rigid concentrators that are relatively heavy and require significant packaging volume and robust deployment schemes. In many ways, these requirements make these systems less appealing than photovoltaic systems. As an alternative to solar thermal power systems with rigid concentrators, solar thermal power systems with thin film inflation-deployed concentrators have low cost, are lightweight, and are efficiently packaged and deployed. Not only are inflatable concentrators suitable for low Earth orbit and geosynchronous orbit applications, but they can be utilized in deep space missions to concentrate solar energy to high-efficiency solar cells.

Tolbert, Carol M.↗
NASA NTRS1980

Radiant energy to electric energy converter

Radiant energy is converted into electric energy by irradiating a capacitor including an ionic dielectric. The dielectric is a sintered crystal superionic conductor, e.g., lanthanum trifluoride, lanthanum trichloride, or silver bromide, so that a multiplicity of crystallites exist between electrodes of the capacitor. The radiant energy cyclically irradiates the dielectric so that the dielectric exhibits a cyclic photocapacitive like effect. Adjacent crystallites have abutting surfaces that enable the crystallites to effectively form a multiplicity of series capacitor elements between the electrodes. Each of the capacitor elements has a dipole layer only on or near its surface. The capacitor is initially charged to a voltage just below the dielectric breakdown voltage by connecting it across a DC source causing a current to flow through a charging resistor to the dielectric. The device can be utilized as a radiant energy detector or as a solar energy cell.

Sher, Arden↗
NASA NTRS2011

Small Solar Electric Propulsion Spacecraft Concept for Near Earth Object and Inner Solar System Missions

Near Earth Objects (NEOs) and other primitive bodies are exciting targets for exploration. Not only do they provide clues to the early formation of the universe, but they also are potential resources for manned exploration as well as provide information about potential Earth hazards. As a step toward exploration outside Earth's sphere of influence, NASA is considering manned exploration to Near Earth Asteroids (NEAs), however hazard characterization of a target is important before embarking on such an undertaking. A small Solar Electric Propulsion (SEP) spacecraft would be ideally suited for this type of mission due to the high delta-V requirements, variety of potential targets and locations, and the solar energy available in the inner solar system.Spacecraft and mission trades have been performed to develop a robust spacecraft design that utilizes low cost, off-the-shelf components that could accommodate a suite of different scientific payloads for NEO characterization. Mission concepts such as multiple spacecraft each rendezvousing with different NEOs, single spacecraft rendezvousing with separate NEOs, NEO landers, as well as other inner solar system applications (Mars telecom orbiter) have been evaluated. Secondary launch opportunities using the Expendable Secondary Payload Adapter (ESPA) Grande launch adapter with unconstrained launch dates have also been examined.

Solar Electric Propulsion (SEP)↗
NASA NTRS2014

High Resolution Mapping of Soils and Landforms for the Desert Renewable Energy Conservation Plan (DRECP)

The Desert Renewable Energy Conservation Plan (DRECP), a major component of California's renewable energy planning efforts, is intended to provide effective protection and conservation of desert ecosystems, while allowing for the sensible development of renewable energy projects. This NASA mapping report was developed to support the DRECP and the Bureau of Land Management (BLM). We outline in this document remote sensing image processing methods to deliver new maps of biological soils crusts, sand dune movements, desert pavements, and sub-surface water sources across the DRECP area. We focused data processing first on the largely unmapped areas most likely to be used for energy developments, such as those within Renewable Energy Study Areas (RESA) and Solar Energy Zones (SEZs). We used imagery (multispectral and radar) mainly from the years 2009-2011.

Mapping↗
DOE OSTI2022

Nanoporous Titanium (Oxy)nitride Films as Broadband Solar Absorbers

Broadband absorption of solar light is a key aspect in many applications that involve an efficient conversion of solar energy to heat. Titanium nitride (TiN)-based materials, in the form of periodic arrays of nanostructures or multilayers, can promote significant heat generation upon illumination thanks to their efficient light absorption and refractory character. In this work, pulsed laser deposition was chosen as a synthesis technique to shift metallic bulk-like TiN to nanoparticle-assembled hierarchical oxynitride (TiO x N y ) films by increasing the background gas deposition pressure. The nanoporous hierarchical films exhibit a tree-like morphology, a strong broadband solar absorption (~90% from the UV to the near-infrared range), and could generate temperatures of ~475 °C under moderate light concentration (17 Suns). The high heat generation achieved by treelike films is ascribed to their porous morphology, nanocrystalline structure, and oxynitride composition, which overall contribute to a superior light trapping and dissipation to heat. These properties pave the way for the implementation of such films as solar absorber structures.

14 SOLAR ENERGY↗
DOE OSTI2022

AMPED EFRC: Alliance for Molecular PhotoElectrode Design for Solar Fuels

Inspired by natural photosynthesis, the mission of the AMPED EFRC was to develop the fundamental molecular basis for solar-driven water oxidation and carbon dioxide reduction catalysis with dye-sensitized photoelectrodes. From 2014-2022, the Center advanced the state-of-the-art in molecule-decorated photoanodes for water oxidation and broke new ground in the development of photocathodes for CO 2 reduction. A collaborative approach brought together experts in inorganic synthesis, organometallic catalysis, interfacial materials synthesis, photoelectrochemistry, and time-resolved dynamics to address by Grand Challenges in the 2007 DOE BESAC report. Since 2009, the UNC EFRC has published 314 peer-reviewed journal articles, and 2 book chapters. More specifically there were 146 peer-reviewed publications,1-146 during the 2014-20 funding cycle, with 80% supported solely by the EFRC, and about half resulting from collaborations among multiple PIs. Three major scientific research areas emerged from AMPED that are described below with details of the most impactful advances for solar energy research.

14 SOLAR ENERGY↗
DOE OSTI2024

Little prairie under the panel: testing native pollinator habitat seed mix establishment at three utility-scale solar sites in Minnesota

Abstract As more land is being utilized for large-scale solar energy projects, there are increasing discussions from stakeholders on how to utilize land under solar panels to promote biodiversity. One path is to plant habitat beneficial to pollinators and other insects, but there have been few long-term studies that examine how different vegetation and seed mixes establish underneath solar panels. This study addresses a scientific gap to determine whether native pollinator seed mixes successfully establish over time under solar arrays using a systematic assessment of eight seed mixes planted at three utility-scale solar sites in Minnesota. We assess establishment with a percent native coverage metric, which is an assessment of native species observations compared to total observations during percent cover analyses in our vegetative test plots. The percent native coverage metric allows for a measurement of how the seed mix established and how the seed mix persists over time. The percent native coverage under and in between the solar photovoltaic (PV) arrays rose from 10% after one year of planting to 58% after three years across all sites, while the native coverage of the full sun control area rose from 9.6% to 70% under the same period, showing that native prairie and pollinator plants successfully established under the array, although to a lesser extent than in full sun conditions. Percent native coverage under the PV arrays rose 5- to 8-fold for each of the three sites from over the course of the study, while the coverage of weeds decreased for all three sites over the same period. Percent native coverage varied by seed mix over the project years, but every seed mix experienced a higher percent native coverage year after year under the PV arrays. Our results did not indicate a difference in establishment across placement within the array; the center, west, and east portions of the areas in between panels had similar establishment rates at two out of three sites, indicating that the same seed mix can be applied throughout the array. Out of 101 plant species seeded, we observed the establishment of 68 species in our vegetative test plots, and we detailed the top 20 observed species to inform future seed mix development. Based on these findings, native pollinator vegetation can establish over time at solar arrays, and it can be suitable for creating habitat at utility-scale solar sites.

14 SOLAR ENERGY↗