Showing papers on "Photovoltaic system published in 1973"

Photovoltaic cell with enhanced power output

Abstract: The photovoltage and photocurrent, and therefore, the power output of photovoltaic cells (solar cells) are markedly enhanced by depositing, on an exposed semiconductor surface of a solar cell, a layer of any one of a very large number of prophyrinic compounds.

Direct solar hydro-electric integrated system and concentrating heliostat for same

Abstract: A fan shaped array of spherical, concave mirrors are mounted for individual rotation about right angle axes and track the sun to concentrate reflected solar rays into the aperture of a tubular boiler/superheater with the superheated steam driving a turbine generator unit. Preferably, the solar powered turbine generator is sized to match generating capacity of an existing hydroelectric system, thus permitting the existing hydro-electric system to operate on a day-to-day basis at higher capacity during any day of clear weather where the solar power plant carries the complete electrical load during those hours when hydro-electric generation ceases.

Spin stabilized vehicle and solar cell arrangement therefor

Abstract: A spin-stabilized vehicle comprising (1) a body and (2) three deployable panels, arranged to present body and panel surfaces covered with photovoltaic or solar cells for increasing the stability and the sun derived power of the craft. The panels are stowed within or wrapped about the craft during ascent towards its utilizable position. When deployed, the panels extend radially from the craft. When extended, the panels are at least as long as the radius of the body. The use of three panels results in a relatively small ripple of the power supplied by the cells as the craft rotates and therefore a relatively high efficiency of cell utilization is provided.

High-Voltage Solar Array Technology

Abstract: REVIOUS high-voltage solar array (HVSA) studies conducted1"7 under the sponsorship of NASA-LeRC have all come to similar conclusions with regard to the relative power system performance gains possible with the HVSA, the generalized techniques for implementation, the specific problem areas associated with device requirements, and the analytic evaluation of HVSA operation in the space environment. This paper considers forms most practical for ion propulsion and high-power communication satellite applications. Attention is focused on defining the concepts for total power systems in greater detail, on breadboard implementation and testing of critical subsystems associated with the total system approach, and on studies to increase the understanding of solar array/ space plasma interactions so that the selection of array materials and physical designs can be based on a knowledge of the requirements and penalties involved.

Adapting Microwave Techniques to Help Solve Future Energy Problems

Abstract: The relationship between microwave techniques and the growing concern for future sources of energy is reviewed. The relationship is specifically explored in the use of a microwave beam to efficiently transport power from an array of solar photovoltaic cells in space to the Earth's surface. Recent advances in power conversion technology and experimental results on overall efficiency of free-space power transmission are reviewed.

Charging circuit for battery-operated devices powered by solar cells

Abstract: A charging circuit for battery-operated devices powered by photovoltaic cells comprising a first diode means connected in parallel to a series-connected resistor and at least one photovoltaic cell, and in parallel to a series-connected second diode means and at least one secondary battery. The terminals of the components of the circuit are connected such that the current from the photovoltaic cells is limited by the first diode means so as to prevent overcharge of the secondary battery while the second diode means is connected so as to prevent reverse current through the photovoltaic cells when the voltage of the secondary battery is higher than that of said photovoltaic cells.

Adapting Microwave Techniques to Help Solve Future Energy Problems

Abstract: The relationship between microwave techniques and the growing concern for future sources of energy is reviewed. The relationship is specifically explored in the use of a microwave beam to efficiently transport power from an array of solar photovoltaic cells in space to the earth's surface. The transition from a laboratory technology of microwave power transmission to a 10-GW 23 200-mi transmission system is examined in detail.

Solar array experiments on the SPHINX satellite

Abstract: The Space Plasma, High Voltage Interaction Experiment (SPHINX) is the name given to an auxiliary payload satellite scheduled to be launched in January 1974. The principal experiments carried on this satellite are specifically designed to obtain the engineering data on the interaction of high voltage systems with the space plasma. The classes of experiments are solar array segments, insulators, insulators with pin holes and conductors. The satellite is also carrying experiments to obtain flight data on three new solar array configurations; the edge illuminated-multijunction cells, the Teflon encased cells and the violet cells.

Solar energy: an infinite source of clean energy

Abstract: Abundance, cleanliness and widespread distri bution are great incentives for the application of solar energy to man's energy requirements. Recent and impend ing fuel shortages, cost increases of energy and environ mental degradation have provided strong incentives for the development of solar energy for wide practical use. However, its low intensity and high variability impose severe econo mic problems in converting it to useful forms. Conversion of solar radiation to thermal, electrical and mechanical energy has been well demonstrated in numerous experi mental systems. Of these methods, those of greatest current interest are the production of heat for the heating and cooling of buildings and the direct, or indirect, conversion to elec tricity. In favorable locations, the costs of solar heating and cooling equipment under development appear to be nearly competitive with fuels; hence, this application is ex pected to be widespread within a very few years. Electric power from solar energy is not now competi...

The advantages of the high voltage solar array for electric propulsion

Abstract: The high voltage solar array offers improvements in efficiency, weight, and reliability for the electric propulsion power system. Conventional power processes and problems associated with ion thruster operation using SERT 2 experience are discussed and the advantages of the HVSA concept for electric propulsion are presented. Tests conducted operating the SERT 2 thruster system in conjunction with HVSA are reported. Thruster operation was observed to be normal and in some respects improved.

Solar Electric Propulsion Stage design

Abstract: This paper summarizes the analyses and design studies performed for the Solar Electric Propulsion Stage (SEPS). Mission analysis results were used to establish general design requirements. A performance sensitivity analysis was then used to define an operational power level of 21 kW for accomplishing a broad range of interplanetary and earth-orbital missions. With this base, propulsion system and stage subsystem design analyses were performed to support concept and configuration studies. Design study areas include solar array, thrust subsystem, thermal control, structures, and astrionics. Results are presented primarily for areas not covered by more specific technical papers (i.e., thrust subsystem, solar array, design requirements and configuration studies).

Thermoelastic analysis of solar cell arrays and their material properties

Abstract: A thermoelastic stress analysis procedure is reported for predicting the thermally induced stresses and failures in silicon solar cell arrays. A prerequisite for the analysis is the characterization of the temperature-dependent thermal and mechanical properties of the solar cell materials. Extensive material property testing was carried out in the temperature range -200 to +200 C for the filter glass, P- and N-type silicon, interconnector metals, solder, and several candidate silicone rubber adhesives. The analysis procedure is applied to several solar cell array design configurations. Results of the analysis indicate the optimum design configuration, with respect to compatible materials, effect of the solder coating, and effect of the interconnector geometry. Good agreement was found between results of the analysis and the test program.

The Satellite Solar Power Station

Abstract: The feasibility of power production on Earth by means of a satellite solar power station is discussed. The status of technology to achieve solar energy conversion, microwave generation, transmission and rectification and transportation to synchronous orbit is reviewed, and costs for the system and components are presented.

Feasibility study of a 110 watt per kilogram lightweight solar array system. Final report

Abstract: This final report summarizes the results of a study to assess the feasibility of a 10, 000 watt solar array panel which has a minimum power-to-mass ratio of 110 watt/kg. The application of this ultralightweight solar array to three possible missions was investigated. With the interplanetary mission as a baseline, the constraining requirements for a geosynchronous mission and for a manned space station mission are presented. A review of existing lightweight solar array system concepts revealed that changes in the system approach are necessary to achieve the specified 110 watt/kg goal. A comprehensive review of existing component technology is presented in the areas of thin solar cells, solar cell covers, welded interconnectors, substrates and deployable booms. Advances in the stateof-the-art of solar cell and deployable boom technology were investigated. System level trade studies required to select the optimum boom bending stiffness, system aspect ratio, bus voltage level, and solar cell circuit arrangement are reported. Design analysis tasks included the thermal analysis of the solar cell blanket, thermal stress analysis of the solar cell interconnectors/substrate, and the thermostructural loading of the deployed boom. A new "V" stiffened solar array concept was conceived and analyzed. This solar array geometry results in increased system stiffness with no increase in total system weight (or reduced weight with the same deployed frequency requirement). A subscale model of this "V" stiffened geometry was fabricated along with a similar model of the conventional planar blanket geometry. These models provide a graphical illustration of the stiffening effect of the "V" geometry.

Solar Power in the Australian Energy Scene

Abstract: Dr Morse discusses the most cost effective ways of utilising solar energy in Australia and points out the possibilities of producing ‘synthetic’ liquid and gaseous fuels from trees and plants

Comparison and evaluation of power plant options for geosynchronous power stations. Part 1: Synchronous solar power

Abstract: The present state-of-the-art is described for the development of solar power generators in far out synchronous orbit for power generation. Concepts of geosynchronous solar power satellites are discussed including photovoltaic arrays for power satellites, solar-thermal power satellites, and power transmission to earth.

Large-scale solar power via the photovoltaic effect

Abstract: As a result of the proposal for the possibility of using the photovoltaic cell for large-scale generation of electricity from sunlight, three questions are posed. What area must be covered by solar cells to generate a significant portion of U. S. energy needs? If generated on the surface of the Earth, what methods of energy storage will be used? How much will photovoltaic solar energy conversion systems cost? It is concluded that the area needed is not unreasonable, that methods of energy storage are available, and that there is reason for optimism with respect to reducing the cost for large-scale power generation from sunlight. (MCW)

Preliminary Reports, Memoranda and Technical Notes of the Materials Research Council Summer Conference Held at La Jolla, California, July, 1973. Volume II. Proceedings of the Discussion Group on Solar Energy Conversion

Abstract: : Discusses applications of solar energy, concentration and collection of solar energy, photovoltaic conversion, ocean thermal gradients, energy storage, and fuel cells.

High voltage solar cell power generating system for regulated solar array development

Abstract: A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kw), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2560 series-connected cells. Each light source consists of twenty 500 watt tungsten iodide lamps providing plus or minus 5 per cent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water cooled plate, a vacuum hold-down system, and air flushing.

Flight performance of the ERTS-1 spacecraft power system

Abstract: The initial spacecraft of the Earth Resources Technology Satellite Program, ERTS-1, was launched on July 23, 1972, and has provided broad earth resource data for use by numerous governmental and scientific agencies. This paper reports on the basic design and flight performance to date of the ERTS-1 power system. The design is based on earlier Nimbus spacecraft power system configurations with modifications introduced to provide increases in average and peak power capabilities. Data is presented showing overall design performance in terms of allowable load duty cycles, solar array capability, and battery charge and discharge behavior. Of special interest is the effect of solar flare activity occurring on August 3 to 7, 1972, in abruptly reducing the solar array output. After 10 months in orbit sufficient power remains for another 18 months of ERTS operation.