Showing papers on "Solar power published in 1976"

Stable solar power source for portable electrical devices

Abstract: The stable solar power source consists of solar cells for converting sunlight into electrical energy and a large capacitor for providing a current reserve to satisfy peak current demands and offset the effects of sunlight variations. The solar cells are mounted beneath a light transmitting thermal shield to minimize thermal induced cell output variations.

Solar power pack apparatus

Abstract: Solar power pack apparatus adaptable for powering emergency equipment at remote locations includes a solar cell array, a rechargeable battery pack, a long shelf-life primary battery pack and switching circuitry interconnecting these elements to provide upon demand immediate and continuous supply of electrical power over extended periods of time notwithstanding environmental conditions which would render unsuitable conventional emergency-use reserve power packs.

A Theory of Concentrators of Solar Energy on a Central Receiver for Electric Power Generation

Abstract: The modeling of the performance of large-area solar concentrators for central receiver power plants is formulated using a continuum field representation of ideal heliostat arrays that accounts for two governing factors: the law of reflection of light rays imposes steering constraints on mirror orientations; the proximity of mirrors creates shadow effects by blocking the incident and/or reflected solar radiation. The results of a steering analysis which develops the space-time characteristics of heliostats and of a shadow analysis which determines the local effectiveness of mirrors in reflecting solar energy to a central point are combined to obtain in closed analytical form the global characteristics of circular concentrators. These characteristics which appear as time profiles for mirror orientations, for effective concentration areas (i.e., reflected solar flux), and for concentration ratios, establish theoretical limits of performance against which actual or realistic solar power systems can be compared and assessed.

Evolution of the satellite solar power station /SSPS/ concept

Abstract: Orbital solar power plants are considered from the viewpoint of technology and costs in terms of photovoltaic conversion, baseline configuration, microwave reception and power generation, transportation, assembly, and maintenance. The economics and development program for the OSPP are briefly discussed. (WDM)

Comparison of candidate solar array maximum power utilization approaches

Abstract: A study was made of five potential approaches that can be utilized to detect the maximum power point of a solar array while sustaining operations at or near maximum power and without endangering stability or causing array voltage collapse. The approaches studied included: (1) dynamic impedance comparator, (2) reference array measurement, (3) onset of solar array voltage collapse detection, (4) parallel tracker, and (5) direct measurement. The study analyzed the feasibility and adaptability of these approaches to a future solar electric propulsion (SEP) mission, and, specifically, to a comet rendezvous mission. Such missions presented the most challenging requirements to a spacecraft power subsystem in terms of power management over large solar intensity ranges of 1.0 to 3.5 AU. The dynamic impedance approach was found to have the highest figure of merit, and the reference array approach followed closely behind. The results are applicable to terrestrial solar power systems as well as to other than SEP space missions.

Comparison of silicon solar cell efficiency for space and terrestrial use

Abstract: The efficiency of silicon p‐n junction photovoltaic cells for solar energy conversion is higher in terrestrial use than in space use by an amount which can be as high as 25%. The power output in terrestrial use is nevertheless lower than in space use because of the lower solar intensity. The explanation for the higher efficiency is that, on traversal of the sunlight through the earth’s atmosphere, water vapor and carbon dioxide absorb energy primarily at wavelengths in the near infrared to which the solar cell is not sensitive. In the present paper a quantitative evaluation of this hypothesis is carried out by numerical determination of the total integrated power and of the number of photons/sec capable of creating hole‐electron pairs corresponding to known solar power distributions for air masses 0, 1, 2, and 3 and by translation of the results into lossless cell efficiencies. The efficiency for silicon cells at air mass 1 for the case of no absorption bands proves to be the same as for air mass 0, where...

Nuclear power: compared to what

Abstract: Decisions that will affect electric power generation at about the end of the century are examined. A nuclear power plant decided upon now could be in operation by 1986 and in its mid-life in the year 2000. Oil and gas will be scarce. The real choices will be among nuclear fission (with breeder reactors in prospect), controlled fusion, bulk solar power, and coal. Other prospects that seem limited or too difficult to develop include geothermal, wind power, ocean thermal gradients, and tidal power. The impact of energy conservation is summarized. The main obstacles to substantial conservation as a viable option are the attitudes and personal desires of people and the inadequacy of enforcement by institutions. 31 references. (MCW)

Solar power station with energy storage - electrolysis sea water into hydrogen and oxygen for later combustion to drive turbine-generator set

Abstract: The solar power station uses the electrical energy derived from a battery of solar cells to electrolyse sea water into gaseous oxygen and hydrogen for storage, and the oxygen and hydrogen are later burnt together to produce sufficient thermal energy to drive a turbine coupled to an electrical generator. The solar cell battery is connected to an electrolysis cell whose two gas outlets are connected to two storage tanks, and the storage tanks are connected to the combustion unit which is coupled to the turbine and generator. The plant produces electricity on an industrial scale.

Transportation options for solar power satellites

Abstract: Advantages of solar power satellites compared to ground-based solar power installations are related to an almost continuous exposure to sunlight and to a much smaller collector area. An investigation of the transportation cost problem is conducted. Transportation systems based on presently understood technology are considered for the deployment of solar power satellites at potentially competitive costs. It is found that the cost of placement in a geosynchronous orbit is reducible to the range from $500 to $1000/kW. Approaches for achieving dramatic cost reductions are discussed.

Solar Power the photochemical alternative

Abstract: Billions of years ago nature developed the technique for converting sunlight into chemical energy. If man could harness this energy as efficiently as the plants do, he might find an ultimate solution to the energy crisis. Creation of an international research institute would be a good first step in this direction

Place of coal in the total energy needs of the United States

Abstract: Solar power and fusion technology are expected to be significant contributors to the total energy supply in the 21st century. Geothermal power and hydropower will continue to supply increasing amounts of energy, largely for local markets in the future. In the immediate future the country must depend largely on the fossil fuel resources and nuclear energy. Coal resources and reserves and the role of coal in the energy market are discussed. Problems facing the coal industry are mentioned. (ERA citation 02:036942)

Exploitation of solar energy

Abstract: The problem of transformng the energy of solar radiation into heat and electricity is reviewed. The main attention is devoted to the possibility of heating up to fairly high temperatures, ~ 500°C, at which modern heat engines, turbines, etc., ensure efficient transformation of heat into electricity. Schemes are examined which are based on the use of comparatively simple concentrators of solar radiation and selective collectors. It is shown that, in addition to selective coatings, selective" gas collectors are of great interest. The possibility of constructing large solar power stations is considered. At the end of the review, approximate estimates are given of the possible cost of a solar power station and the prospects for increasing the competitiveness of solar energy are discussed.

Chemical engineering aids solar energy

Abstract: There is substantial promise in the application of chemical engineering principles to large-scale collection of solar energy for production of electricity. Experimental work on energy storage and solar furnace chemical reactors is needed to evaluate practicability. Subsequent engineering for mass production of solar collection field components will then determine the economic feasibility of this approach to solar power compared with alternate options for energy procurement.

Use of satellites to determine optimum locations for solar power stations

Abstract: Ground measurements of solar radiation are too sparse to determine important mesoscale differences that can be of major significance in solar power station locations. Cloud images in the visual spectrum from the SMS/GOES geostationary satellites are used to determine the hourly distribution of sunshine on a mesoscale in the continental United States excluding Alaska. Cloud coverage and density as a function of time of day and season are considered through the use of digital data processing techniques. Low density cirrus clouds are less detrimental to solar energy collection than other types; and clouds in the morning and evening are less detrimental than those during midday hours of maximum insolation. The seasonal geographic distributions of sunshine are converted to Langleys of solar radiation received at the earth's surface through the use of transform equations developed from long-term measurements of these two parameters at 18 widely distributed stations. The high correlation between measurements of sunshine and radiation makes this possible. The output product will be maps showing the geographic distribution of total solar radiation on the mesoscale which is received at the earth's surface during each season.

Microwave power tubes for space applications

Abstract: Feasibility evaluations of klystron amplifiers for conversion of solar power in synchronous orbit into microwave power at 2.4 GHz and transmission to earth were carried out. It was found that amplitrons and klystrons, using a depressed collector augmentation, can achieve efficiencies in excess of 80% if the power output is kept higher than 50 kW. Body wound selenoid provides the needed beam-focusing field. Narrow bandwidth requirements permit a low cathode loading density of 0.5 A/sq cm produced at approximately 850 centigrades. Emission tests indicate a potential life expectancy of 20 to 40 years.

Investigation of Beamed Energy Concepts for Propulsion. Systems Studies. Volume I.

Abstract: : The objective of this program is to assess the feasibility of the beamed energy propulsion concept for Air Force missions. The results of the study indicate that beamed energy propulsion is technically feasible. No fundamental obstacles have been identified. However considerable technical development is needed in many areas before the concept can be operationally implemented. In order to minimize the required collector area, laser concepts are preferred over microwaves. If space based laser transmitter concepts are to be cost effective they will require the availability of megawatt level space nuclear or solar power stations. In view of the large total energy required for each mission, ground based transmitters will be most cost effective when they are operated closed cycle from central station electric power. Laser transmitting ranges greater than several hundred nautical miles will result in excessive collector sizes. Therefore, ground based transmitters applications will be restricted to orbital functions which can be performed at low orbital altitudes. Three promising applications have been identified. The laser powered tug can be cost effective compared to an advanced cryogenic tug. Apsidal rotation correction and drag make-up are two other missions where significant advantages may be realized for the laser powered concept.

Space solar power - An available energy source

Abstract: The development of satellite solar power stations is described with attention given to station design and assembly in space. Problems associated with conversion of solar energy into microwaves and with getting the station into orbit are considered. The use of a solar propulsion system for pushing the station to high orbit is discussed along with questions of station lifetime (estimated to be about thirty years). The paper is copiously illustrated with drawings projecting various aspects of station design and utilization.

Nonconventional energy trends to supplement our petroleum reserves

Abstract: A review primarily of the prospects for solar energy covers various nonfossil primary energy resources and the distinction between energy for instantaneous application vs energy that can be stored; the relatively unlimited potential of solar energy on a global basis; potential for using solar energy to replace petroleum in supplying energy for oil refining; solar power stations and conversion of power to hydrogen for storage; and miscellaneous small applications of solar energy as in solar cookers, which in the aggregate can result in very great savings of oil

Integration of solar thermal power plants into electric utility systems

Abstract: The findings of a study designed to fill the need for an electric utility to evaluate solar thermal power plants are summarized. Calculations are described which were used to compute the economic value of solar power plants to an electric utility under assumptions that are valid today. Topics covered are: reliability evaluation, economic evaluation, storage, system operation, and cost and design considerations. (MHR)

Solar power plant

Abstract: PURPOSE:Effective solar power motor for directly converting solar power into magnetic attraction force.

Development of the solar power central receiver concept

Abstract: The main incentive for the development of the solar central receiver concept is to examine the collection and efficient use of solar energy to produce electricity. The particular concepts being developed to accomplish this goal by various contractors are described and Sandia Livermore's role as technical manager is discussed. In addition, the ERDA plan for eventual commercialization of this concept, as well as the role and use of the Sandia solar thermal test facility, is described. Furthermore, details of particular subsystem components, as well as potentially fruitful research areas for Sandia and other development laboratories to pursue which can lead to performance improvements, are discussed.

Coming - Solar power plants

Abstract: According to Sandia Laboratories, technical manager for ERDA's solar central-receiver power project, the U.S. should have a 10-MW pilot solar electric power plant by 1980. Other milestones in the program, which began in 1975, include operation of a 5-MWth solar test facility in 1977, and the first commercial demonstration plant by 1985. The solar central-receiver concept incorporates a field of individually guided and controlled mirrors, called heliostats, which offer a 2-degree-of-freedom focusing system. Simulating a very large, steerable Fresnel reflector, the heliostat field redirects the Sun's energy to a tower-mounted receiver, which absorbs the radiant energy in a circirculating fluid for direct powering of a steam-turbine/generator or for storage. The system designs proposed for the pilot plant appear workable, requiring no technological breakthroughs. However, major cost reductions are warranted before the concept is economically competitive.

Solar Power Collector Breadboard Test Program

Abstract: Itek's objective in the field of high temperature solar energy has been to develop an efficient and inexpensive method of collecting the sun's energy - ultimately for use in a solar-thermal-electric power plant. A unique and simple concept has emerged in the development process. On the basis of that concept, Itek received a grant from the National Science Foundation to conduct a Solar Power Collector Breadboard Test Program. *This paper describes Itek's collector approach and discusses the test program. A summary is given including the program objectives, hardware problems encountered, corrective actions taken, performance measurements and evaluation, and results of a preliminary operational system cost analysis.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.