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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Solar dynamic power system development for Space Station Freedom

The development of a solar dynamic electric power generation system as part of the Space Station Freedom Program is documented. The solar dynamic power system includes a solar concentrator, which collects sunlight; a receiver, which accepts and stores the concentrated solar energy and transfers this energy to a gas; a Brayton turbine, alternator, and compressor unit, which generates electric power; and a radiator, which rejects waste heat. Solar dynamic systems have greater efficiency and lower maintenance costs than photovoltaic systems and are being considered for future growth of Space Station Freedom. Solar dynamic development managed by the NASA Lewis Research Center from 1986 to Feb. 1991 is covered. It summarizes technology and hardware development, describes 'lessons learned', and, through an extensive bibliography, serves as a source list of documents that provide details of the design and analytic results achieved. It was prepared by the staff of the Solar Dynamic Power System Branch at the NASA Lewis Research Center in Cleveland, Ohio. The report includes results from the prime contractor as well as from in-house efforts, university grants, and other contracts. Also included are the writers' opinions on the best way to proceed technically and programmatically with solar dynamic efforts in the future, on the basis of their experiences in this program.

Source record↗
NASA NTRS2006

Recent Advances in Solar Sail Propulsion at NASA

Supporting NASA's Science Mission Directorate, the In-Space Propulsion Technology Program is developing solar sail propulsion for use in robotic science and exploration of the solar system. Solar sail propulsion will provide longer on-station operation, increased scientific payload mass fraction, and access to previously inaccessible orbits for multiple potential science missions. Two different 20-meter solar sail systems were produced and successfully completed functional vacuum testing last year in NASA Glenn's Space Power Facility at Plum Brook Station, Ohio. The sails were designed and developed by ATK Space Systems and L'Garde, respectively. These sail systems consist of a central structure with four deployable booms that support the sails. This sail designs are robust enough for deployments in a one atmosphere, one gravity environment, and are scalable to much larger solar sails-perhaps as much as 150 meters on a side. In addition, computation modeling and analytical simulations have been performed to assess the scalability of the technology to the large sizes (>150 meters) required for first generation solar sails missions. Life and space environmental effects testing of sail and component materials are also nearly complete. This paper will summarize recent technology advancements in solar sails and their successful ambient and vacuum testing.

Johnson, Les↗
NASA NTRS2006

Recent Advances in Solar Sail Propulsion Systems at NASA

Supporting NASA's Science Mission Directorate, the In-Space Propulsion Technology Program is developing solar sail propulsion for use in robotic science and exploration of the solar system. Solar sail propulsion has the potential to provide longer on-station operation, increased scientific payload mass fraction, and access to previously inaccessible orbits for multiple potential science missions. Two different 20-meter solar sail systems were produced and successfully completed functional vacuum testing last year in NASA Glenn s Space Power Facility at Plum Brook Station Ohio. The sails were designed and developed by ATK Space Systems and L'Garde, respectively. The sail systems consist of a central structure with four deployable booms that support the sails. The sail designs are robust enough for deployments in a one atmosphere, one gravity environment and are scalable to much larger solar sails - perhaps as large as 150 meters on a side. In addition, computational modeling and analytical simulations have been performed to assess the scalability of the technology to the large sizes (150 meters) required to implement the first generation of missions using solar sails. Life and space environmental effects testing of sail and component materials are also nearly complete. This paper will summarize recent technology advancements in solar sails and their successful ambient and vacuum environment testing.

Johnson, Les↗
NASA NTRS1979

Problems encountered in solar heating and cooling systems

Report discussing various experiences of workers at Marshall Space Flight Center in developing solar heating and cooling systems is presented. Presents compilation of problems and their resolutions which can assist designers of solar-energy systems and prevent repetition of errors.

Cash, M.↗
DOE OSTI2024

DERiving Community Economic Development through Distributed Solar

This report explores how distributed solar stakeholders can plan and align economic development with existing community priorities while advancing new solar projects. Because the amount of local community influence drives community economic development, we note the need for investment in community ownership models, which are scarce today. This report seeks to outline the current barriers to community-led economic development through distributed solar, best practices for implementation, and recommendations for sector stakeholders.

14 SOLAR ENERGY↗
NASA NTRS1983

Solar thermal technology development: Estimated market size and energy cost savings. Volume 2: Assumptions, methodology and results

Estimated future energy cost savings associated with the development of cost-competitive solar thermal technologies (STT) are discussed. Analysis is restricted to STT in electric applications for 16 high-insolation/high-energy-price states. Three fuel price scenarios and three 1990 STT system costs are considered, reflecting uncertainty over future fuel prices and STT cost projections. Solar thermal technology research and development (R&D) is found to be unacceptably risky for private industry in the absence of federal support. Energy cost savings were projected to range from $0 to $10 billion (1990 values in 1981 dollars), depending on the system cost and fuel price scenario. Normal R&D investment risks are accentuated because the Organization of Petroleum Exporting Countries (OPEC) cartel can artificially manipulate oil prices and undercut growth of alternative energy sources. Federal participation in STT R&D to help capture the potential benefits of developing cost-competitive STT was found to be in the national interest. Analysis is also provided regarding two federal incentives currently in use: The Federal Business Energy Tax Credit and direct R&D funding.

Gates, W. R.↗
NASA NTRS1979

Silicon Solar Cell Process Development, Fabrication and Analysis

The standard solar cells (2x2 cm) from the cast silicon (HEM) showed a maximum AMO efficiency of 10.1%. Cells from the low resistivity material (0.5 ohm-cm) showed lower performance than those of the high resistivity cast silicon (3 ohm-cm), an average efficiency 9.5% versus 7.6%. Maximum AMO efficiency of the standard solar cells from the EFG (RH) ribbons was about 7.5%. The solar cells from the controlled SiC, using the displaced die, showed more consistent and better performance than those of the uncontrolled SiC ribbons, an average efficiency of 6.6% versus 5.4%. The average AMO efficiency of the standard SOC solar cells were about 6%. These were large area solar cells (an average area of 15 sq cm). A maximum efficiency of 7.3% was obtained. The SOC solar cells showed both leakage and series resistance problems, leading to an average curve fill factor of about 60%.

Yoo, H. I.↗
NASA NTRS1979

Silicon Solar Cell Process Development, Fabrication and Analysis

The standard solar cells (2x2 cm) from the cast silicon heatexchanger method) showed a maximum AMO efficiency of 10.1%. Cells from low resistivity material (0.5 ohm-cm) showed lower performance than those of the high resistivity cast silicon (3 ohm-cm), an average efficiency 9.5% versus 7.6% Maximum AMO efficiency of the standard solar cells (2x2 cm) from the EFG (RH) ribbons was about 7.5%. The solar cells from controlled SiC, using the displaced die, showed more consistent and better performance than those of the uncontrolled SiC ribbons, an average efficiency of 6.6% versus 5.4% The average AMO efficiency of the standard silicon ceramic (soc) solar calls were about 6%. These were large area solar cells (an average area of 15 sq cm). A maximum efficiency of 7.3% was obtained. The SOC solar cells showed both leakage and series resistance problems, leading to an average curve fill factor of about 60%.

Yoo, H. I.↗
NASA NTRS1979

Silicon Solar Cell Process Development, Fabrication and Analysis, Phase 1

Solar cells from RTR ribbons, EFG (RF and RH) ribbons, dendritic webs, Silso wafers, cast silicon by HEM, silicon on ceramic, and continuous Czochralski ingots were fabricated using a standard process typical of those used currently in the silicon solar cell industry. Back surface field (BSF) processing and other process modifications were included to give preliminary indications of possible improved performance. The parameters measured included open circuit voltage, short circuit current, curve fill factor, and conversion efficiency (all taken under AM0 illumination). Also measured for typical cells were spectral response, dark I-V characteristics, minority carrier diffusion length, and photoresponse by fine light spot scanning. the results were compared to the properties of cells made from conventional single crystalline Czochralski silicon with an emphasis on statistical evaluation. Limited efforts were made to identify growth defects which will influence solar cell performance.

Yoo, H. I.↗
NASA NTRS2002

Solar Selective Coatings Developed for Space Power Applications

A solar collector having the combined properties of high solar absorptance, low infrared emittance, and high thermal conductivity is envisioned for space power applications on minisatellites. A high solar absorptance is needed to collect as much of the incident solar radiation as possible and a low infrared emittance is needed to minimize radiant energy losses. A lightweight material having a high thermal conductivity is needed to transport the absorbed energy to where it is needed. Such a solar collector may be used with a low temperature-differential heat engine to provide electric power to the minisatellite components or as a source of thermal energy for a thermal bus that would heat remote regions of the spacecraft. The key to such a collector is the use of cermet coatings. Cermet coatings are composed of molecular islands of metal embedded in a three-dimensional matrix of dielectric. Recent research on molecular mixtures of aluminum and aluminum oxide at the NASA Glenn Research Center has yielded cermet coatings with a solar absorptance a of 0.797 and an infrared emittance epsilon of 0.131, yielding an alpha/epsilon ratio of 6. Although additional work is needed to further increase the alpha/epsilon ratio, these coatings are attractive owing to their potential durability in the space environment. The aluminum oxide surface should provide substantial protection from the atomic oxygen found in low Earth orbit. To help minimize emittance, these coatings are deposited on a smooth surface. The selected surface is aluminum that has been diamond turned to a mirror finish. Cermet coatings are manufactured by sputter deposition. To achieve the desired variable composition, Glenn's researchers implemented a novel approach using a cylindrical target composed of aluminum and aluminum oxide. Rotating the cylinder during the deposition process yields a coating of variable composition. A photograph of the custom-made aluminum and aluminum oxide cylindrical target installed in the sputter deposition chamber is shown.

Jaworske, Donald A.↗
NASA NTRSDate not supplied

Space Technology Mission Directorate - Game Changing Development Program - Vertical Solar Array Technology Project

The Vertical Solar Array Technology (VSAT) project is focused on the development of solar array technologies necessary for sustained presence on the lunar surface circa 2028. Existing solar array structures and deployment system technologies are designed for either zero-g or horizontal surface deployment. VSAT will explore vertical array deployment on extension masts of up to 10m in length in order to capture near continuous sun light at the lunar south pole.

GCD↗
NASA NTRS1995

Space concentrator solar cells based on multilayer LPE grown AlGaAs/GaAs heterostructure

The high efficiency solar cells based on multilayer AlGaAs/GaAs heterostructures, prepared by low temperature liquid phase epitaxy (LPE), were developed and tested. An investigation of the low temperature LPE process for the crystallization of AlGaAs heterostructures of as high as 24.0 to 24.7 percent under AMO conditions at concentration ratios of 20 to 100x, were reached. Developed solar cells show substantial radiation resistance to the damage induced by 3.75 MeV electrons.

Khvostikov, V. P.↗
DOE OSTI2024

Solar Energy Zone Market Analysis for the Afton Region of New Mexico

This report examines the commercial viability of the Afton solar energy zone (SEZ) in southern New Mexico based on market conditions in 2022. The Bureau of Land Management may designate a SEZ on federal land to expedite environmental review and permitting for solar energy projects. The purpose of this analysis is to understand whether current market conditions support solar development in the SEZ.

14 SOLAR ENERGY↗
DOE OSTI2024

Community Planning for Solar: Toolkit Overview

UMass Clean Energy Extension (CEE) and its partners have designed the Community Planning for Solar Toolkit to help municipalities in Massachusetts and throughout the Northeast proactively plan for solar PV development in their communities. The tools and processes are designed with rural and suburban communities in mind, though some of the tools may also apply to urban settings. Community Planning for Solar empowers community residents and officials to take the lead in solar development by providing communities with the resources that can help them to: (1) Identify and prioritize locations in the community for solar development; (2) Evaluate various solar financing options and provide guidance on community benefits that best match community goals and needs; (3) Assess their community's unique resources, solar development options, goals, and preferences regarding solar development; (4)Develop a Community Solar Action Plan.

14 SOLAR ENERGY↗
DOE OSTI2024

Rooftop Solar in Lawrence, MA: Community Perspectives, Deceptive Practices, and Financing Options

This report was prepared as part of the U.S. Department of Energy's Communities Local Energy Action Program (Communities LEAP) pilot competitive technical assistance for the Lawrence Massachusetts Stakeholder Coalition (LSC) composed of The City of Lawrence, All In Energy, MassDevelopment, Mill City Community Investments, BlocPower and Groundwork Lawrence, and led by Browning the Green Space. The LSC identified rooftop solar photovoltaics as a top priority for this technical assistance opportunity. Lawrence faces high energy burden and electricity prices, thus rooftop solar can be a tool to help lower those costs. However, the coalition received feedback that some solar companies were using deceptive and unfair practices when marketing, selling, or financing solar energy, costing residents more money than utility rates and increasing the energy burden. This project sought to address rooftop solar community priorities through two pathways: 1. facilitating community engagement to understand community perspectives and experiences with rooftop solar development; and 2. conducting a financial cash-flow analysis highlighting the varying fiscal outcomes for rooftop solar adopters based off rooftop solar leasing, ownership, or buying electricity from the utility (National Grid).

14 SOLAR ENERGY↗
NASA NTRS1989

A three solar cell system based on a self-supporting, transparent AlGaAs top solar cell

Development of a three solar cell stack can lead to practical efficiencies greater than 30 percent (1x,AM0). A theoretical efficiency limitation of 43.7 percent at AM0 and one sun is predicted by this model. Including expected losses, a practical system efficiency of 36.8 percent is anticipated. These calculations are based on a 1.93eV/1.43eV/0.89eV energy band gap combination. AlGaAs/GaAs/GaInAsP materials can be used with a six-terminal wiring configuration. The key issues for multijunction solar cells are the top and middle solar cell performance and the sub-bandgap transparency. AstroPower has developed a technique to fabricate AlGaAs solar cells on rugged, self-supporting, transparent AlGaAs substrates. Top solar cell efficiencies greater than 11 percent AM0 have been achieved. State-of-the-art GaAs or InP devices will be used for the middle solar cell. GaInAsP will be used to fabricate the bottom solar cell. This material is lattice-matched to InP and offers a wide range of bandgaps for optimization of the three solar cell stack. Liquid phase epitaxy is being used to grow the quaternary material. Initial solar cells have shown open-circuit voltages of 462 mV for a bandgap of 0.92eV. Design rules for the multijunction three solar cell stack are discussed. The progress in the development of the self-supporting AlGaAs top solar cell and the GaInAsP bottom solar cell is presented.

Negley, Gerald H.↗