Exergy and economic approaches for integrating power and green hydrogen production with a novel solar-ORC system

Abstract

In this study, a hydrogen production system integrated with a solar-organic Rankine cycle (S-ORC) system is examined. Experimental studies on the generation of electrical energy at low temperatures are relatively limited in the literature, as low temperatures are typically preferred for thermal energy production in domestic applications. This study presents experimental results regarding the use of different working fluids in the ORC system. A evacuated tube heat pipe solar collector (ETHPSC) was employed to harness solar energy. The thermal energy obtained from the collector was utilized in the integrated ORC system. Various fluids were comparatively analyzed within the S-ORC system. The net energy produced by the ORC system was entirely used for hydrogen production in an electrolyser. The results indicate that the exergy efficiencies of the entire system for hydrogen production were calculated as 6.67 %, 7.13 %, 9.56 %, and 7.59 % when using R134a, R1234yf, R410a, and R32 as working fluids in the ORC system, respectively. Furthermore, at higher collector outlet temperatures, the lowest hydrogen production cost of $0.9793/kg was achieved when R1234yf was used as the working fluid.