Energy analysis of a hybrid solar concentrating photovoltaic/concentrating solar power (CPV/CSP) system

Abstract

This study presents a novel solar concentrating photovoltaic/concentrating solar power (CPV/CSP) hybrid system, which mainly contains CPV modules with an evaporative cooling subsystem, a thermal receiver and an organic Rankine cycle (ORC). The cooling fluid is boiled when cooling the CPV modules, and superheated vapor that is effective for power generation with an ORC is generated after absorbing low-concentration solar radiation in the thermal receiver. A steady-state physical model is developed to carry out energy analysis of the hybrid system. The results show that when saturated vapor is fed into the thermal receiver, the peripheral low-concentration solar radiation that is discarded in conventional CPV or CPV/thermal systems is effective to get a high-temperature superheated vapor (e.g., above 120 °C). The overall solar-to-electricity efficiency can be increased from 28.4 % for the conventional CPV system to 44 % for the hybrid system with 500 suns. Even though the overall efficiency decreases from 44.0 % to 36.8 % when the concentration ratio increases from 500 to 2,000 suns, there is still a considerable efficiency improvement compared with the conventional CPV systems. The results indicate that the proposed hybrid system provides a viable solution for solar power generation with high efficiencies.