الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
Recently there has been considerable Interest in the use of solar energy to meet a substantial of the nation’s energy needs. The use of photovoltaic device has been proposed as one means of converting the sun’s energy directly to electricity. The low efficiency of
present devices (less than 20% ) and the relatively low density of
2 the sun’s radiation at the surface of the earth (order of Ikw/m )
requires considerable areas of photovoltaic devices resulting in a high capital investment per K.W.
There are two approaches to make solar cell arrays cheaper, the first is based on the technological development of new materials for the production of solar cells. Hydrogenerated amorphous silicon has proved to be a potentially useful material for this purpose. The second approach is to reduce the area of photovoltaic devices by the use of light concentrators which are presently known to cost conside¬rably less per unit area than do the solar cells.
It is not clear at this time as to what is the optimum combina¬tion of solar cell design and concentration ratio. However the cost tradeoff of present concentrating systems are such that reduction of solar cell areas of 1000:1 appears to be economical from the point of view of both dollar cost and energy payback ratio (useful energy recieved from photovoltaic system over its life divided by the energy expended in manufacturing the system).