A General Method for the Evaluation of Possible Systems for Electric Generation with Solar Energy

The purpose of this paper is the development of an easily applied general method of analysis of any type of potential system for electric generation with solar energy. It assumes that data for the site of the potential solar-electric plant collected over a period of ten or more years are available. The most important such data for this analysis are the mean annual insolation per unit area, I, in Btu per square foot (Btu/ft2), and the peak rate of solar insolation, P, in Btu/ft2 hr. Secondary site data include the mean number of hours of sunshine on the site per year, measures of the seasonal variation between summer and winter, and the frequency of damaging storms. For the proposed solar-electric generating plant, only two characteristics are required: the gross heat rate, H, in Btu of solar radiation received on the collectors per kilowatt hour (kWhr) of electricity delivered in usable form, and the amount and efficiency of energy storage included in the plant. The heat rate for the system depends on a series of efficiencies or losses as the received solar radiation passes through successive stages of the system to its electrical output. For fully engineered systems it can be estimated within fairly narrow limits. For k speculative systems which might materialize as a result of future research and development, an assumed value can be chosen on the basis of what is hoped to be achieved.