Effects of various parameters on energy and exergy efficiencies of a solar thermal hydrogen production system

•A solar thermal hydrogen production system is proposed and analyzed.•The effects of various parameters on energy and exergy efficiencies of a solar thermal hydrogen production system are investigated.•Both energy and exergy efficiencies of the present system are studied and evaluated for comparison purposes.

In the present paper, a solar-based thermally-driven hydrogen production system is considered and analyzed thermodynamically, and a performance assessment study of this system is undertaken based on both energy and exergy efficiencies. A case study is also presented to analyse the system performance based on various climatic parameters, for example, intensity of solar radiation, ambient temperature, etc. The effects of such operating conditions and system parameters on the energy and exergy efficiencies of the system are also investigated. The results show that the concentrator performs well with higher solar radiations, concentration factor, absorptivity of absorber surface, reflectivity of reflector surface, with lower heat loss coefficients and area of collector surface. The exergy efficiency of the collector increases with the temperature of the collector surface initially, becomes maximum (36% approximately) at 400 °C and then reduces with further increase in temperature. Finally, overall energy and exergy efficiencies of this solar thermal hydrogen system are evaluated and compared for practical applications.