Technical study of a hybrid solar-geothermal power plant and its application to a thermal design course

Abstract

An energetic model for a hybrid solar-geothermal electric power plant (HSGEPP) is developed to explore the extent to which solar thermal resources can extend and enhance marginal and declining geothermal fields. The model is developed and presented to allow replication in a 4th-year solar engineering thermal design course. The model is applied to a HSGEPP being developed in Turkey, and simulations are run using a typical meteorological year formatted data set. The solar fraction ( fs) of the HSGEPP is equal to the fractional decrease in the geothermal resource usage. The increase in annual fs with the collector field’s solar multiple (Ms) is linear up to approximately fs�0.25 for Ms�1.25, after which the rate of increase in fs begins to decay and fs approaches 0.37 for Ms�5. For Ms�1.25, the monthly solar fraction ranges from 0.05 in December to 0.43 in July.