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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Enhanced solar energy options using earth-orbiting mirrors

A system of orbiting space reflectors is described, analyzed, and shown to economically provide nearly continuous insolation to preselected ground sites, producing benefits hitherto lacking in conventional solar farms and leading to large reductions in energy costs for such installations. Free-flying planar mirrors of about 1 sq km are shown to be optimum and can be made at under 10 g/sq m of surface, thus minimizing material needs and space transportation costs. Models are developed for both the design of such mirrors and for the analysis of expected ground insolation as a function of orbital parameters, time, and site location. Various applications (agricultural, solar-electric production, weather enhancement, etc.) are described.

Gilbreath, W. P.↗
NASA NTRS1980

New technologies for solar energy silicon - Cost analysis of BCL process

New technologies for producing polysilicon are being developed to provide lower cost material for solar cells which convert sunlight into electricity. This article presents results for the BCL Process, which produces the solar-cell silicon by reduction of silicon tetrachloride with zinc vapor. Cost, sensitivity, and profitability analysis results are presented based on a preliminary process design of a plant to produce 1000 metric tons/year of silicon by the BCL Process. Profitability analysis indicates a sales price of $12.1-19.4 per kg of silicon (1980 dollars) at a 0-25 per cent DCF rate of return on investment after taxes. These results indicate good potential for meeting the goal of providing lower cost material for silicon solar cells.

Yaws, C. L.↗
NASA NTRS1974

Solar-energy absorber: Active infrared (IR) trap without glass

Absorber efficiency can be improved to 90% by removing glass plates and using infrared traps. Absorber configuration may be of interest to manufacturers of solar absorbers and to engineers and scientists developing new sources of energy.

Brantley, L. W., Jr.↗
NASA NTRS1988

Multispectral observations complementary to the study of high-energy solar phenomena

Multispectral observations of phenomena associated with nonthermal events on the sun and characterized by the transient acceleration of electrons and ions to energies ranging from several keV to tens of GeV are discussed. It is shown that observations of the thermal and quasi-thermal phenomena preceeding, coinciding with, and following the impulsive acceleration and heating event itself can be used to study the evolution of magnetic structures in the solar convection zone and atmosphere. Observational techniques are discussed in detail.

Walker, Arthur B. C., Jr.↗
NASA NTRS1977

Fresnel-lens solar-energy concentrator

Theoretical and experimental evaluations have produced lens and concentrator data that improve collector performance. Methodology is useful to designers of Fresnel-lens solar concentrators.

Allums, S. L.↗
NASA NTRS1977

A solar energy estimation procedure using remote sensing techniques

The objective of this investigation is to design a remote sensing-aided procedure for daily location-specific estimation of solar radiation components over the watershed(s) of interest. This technique has been tested on the Spanish Creek Watershed, Northern California, with successful results.

Khorram, S.↗
NASA NTRS1978

Inexpensive, portable, integrating solar energy meter

Silicon-cell insolometer automatically measures and totals amount of energy available in sunlight falling on the earth at specific location over selected period of time. Device incorporates single silicon solar cell as sensing element and relies on principle that short-circuit current from solar cell is directly proportional to amount of light that shines on cell.

Masters, R. M.↗
NASA NTRS1974

Selective coating for collecting solar energy on aluminum

Presently used coatings, which were originally developed for brass, copper, and steel substrates, yield relatively low absorptance/emittance ratios when applied to aluminum. Efficient, black-nickel plating applied to aluminum substrate enhances solar absorptance to 93% and reduces emittance to 6%.

Lowery, J. R.↗
NASA NTRS1978

Greenbelt Community Project: Solar energy retrofit for a multi-family dwelling

A cooperative project was initiated between Goddard Space Flight Center and the nearby community of Greenbelt, Maryland. The purpose was to design, install and operate an experimental solar heating system on a group of four tandem town houses. The system was successfully developed and is operating. A description is given of the design, installation, system operation and performance as well as the important considerations for judging the economic feasibility of solar heating systems.

Hymowitz, E. W.↗
NASA NTRS1979

Computer Program for Assessing the Economic Feasibility of Solar Energy for Single Family Residences and Light Commercial Applications

Computer program, SHCOST, was used to perform economic analyses of operational test sites. The program allows consideration of the economic parameters which are important to the solar system user. A life cycle cost and cash flow comparison is made between a solar heating system and a conventional system. The program assists in sizing the solar heating system. A sensitivity study and plot capability allow the user to select the most cost effective system configuration.

Forney, J. A.↗
NASA NTRS1990

Preliminary design of an advanced Stirling system for terrestrial solar energy conversion

A preliminary design was generated for an advanced Stirling conversion system (ASCS) that will be capable of delivering about 25 kW of electric power to an electric utility grid. Stirling engines are being evaluated for terrestrial solar applications. A two-year task to complete detailed design, fabrication, assembly and testing of an ASCS prototype began in April, 1990. The ASCS is designed to deliver maximum power per year over a range of solar inputs with a design life of 30 years (60,000 h). The ACSC has a long-term cost goal of about $450 per kilowatt, exclusive of the 11-m parabolic dish concentrator. The proposed system includes a Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator. The major thrusts of the preliminary design are described, including material selection for the hot-end components, heat transport system (reflux pool boiler) design, system thermal response, improved manufacturability, FMECA/FTA analysis, updated manufacturing cost estimate, and predicted system performance.

White, M. A.↗
NASA NTRS1973

Solar energy outside the earth's atmosphere.

Spectral irradiance measurements at high altitude were made using a variety of monochromators and filter radiometers. The results of all recent high-altitude measurements have been critically examined by an ad hoc committee on 'Solar Electromagnetic Radiation.' The committee has proposed standard values for engineering use for the solar constant and the solar spectrum. These values are presented and also the reasons for recommending their acceptance. Detailed comparisons are made between the revised spectral irradiance values and those which had been widely accepted in earlier years. New values are computed for frequently cited astrophysical quantities which are derived from the solar constant and the solar spectrum. The spectrum is extended to 10 A in the X-ray range and to 10 m in the microwave range. The revised value of the solar constant is 1.94 cal per sq cm per min. The proposed standard solar spectrum shows significant differences from other curves throughout the spectral range.

Thekaekara, M. P.↗
NASA NTRS1981

Fire-station solar-energy system--Kansas City, Missouri

Screen-walled, flat-plate air collectors are part of award-winning architectural design; concrete-box storage subsystem, domestic hot-water preheat tank, blowers, pumps, heat exchangers, ducting, controls, and plumbing complete solar system. Design provides half of space heating and 75 percent of heat for domestic hot-water for fire station. Report includes historical narrative of project along with detailed drawings, charts, and product literature.

Source record↗
NASA NTRS1974

Direct observations of the charge states of low energy solar particles

The charge states of carbon and oxygen of solar origin have been measured directly in interplanetary space. At 100 keV per nucleon the C(+5)/C(+6) and O(+7)/O(+8) ratios are 1.8 and 1.6, respectively. Abundance ratios of low energy heavy nuclei to He are found which are significantly larger than the corresponding photospheric values. The enhancement of O/He is 35, and both Si/He and Fe/He are overabundant by a factor of 100. To explain these observations a mechanism is proposed which first preferentially accelerates heavy ions and is followed by either storage of these ions in the coronal regions or strong adiabatic deceleration.

Gloeckler, G.↗
NASA NTRS1989

A space-based combined thermophotovoltaic electric generator and gas laser solar energy conversion system

This paper describes a spaceborne energy conversion system consisting of a thermophotovoltaic electric generator and a gas laser. As a power source for the converson, the system utilizes an intermediate blackbody cavity heated to a temperature of 2000-2400 K by concentrated solar radiation. A double-layer solar cell of GaAs and Si forms a cylindrical surface concentric to this blackbody cavity, receiving the blackbody radiation and converting it into electricity with cell conversion efficiency of 50 percent or more. If the blackbody cavity encloses a laser medium, the blackbody radiation can also be used to simultaneously pump a lasing gas. The feasibility of blackbody optical pumping at 4.3 microns in a CO2-He gas mixture was experimentally demonstrated.

Yesil, Oktay↗