Assessment of electricity and hydrogen production performance of evacuated tube solar collectors

In this work, a unified renewable energy system has designed to assess the electricity and hydrogen production. This system consists of the evacuated tube solar collectors (ETSCs) which have the total surface area of 300 m2, a salt gradient solar pond (SGSP) which has the surface area of 217 m2, an Organic Rankine Cycle (ORC) and an electrolysis system. The stored heat in the heat storage zone (HSZ) transferred to the input water of the ETSCs by means of an exchanger and thereby ETSCs increase the temperature of preheated water to higher level as much as possible that primarily affects the performance of the ORC. The balance equations of the designed system were written and analyzed by utilizing the Engineering Equations Solver (EES) software. Hence, the energy and exergy efficiencies of the overall system were calculated as to be 5.92% and 18.21%, respectively. It was also found that hydrogen generation of the system can reach up to ratio 3204 g/day.