Thermochemical H2 production via solar driven hybrid SrO/SrSO4 water splitting cycle

This article reports the thermodynamic efficiency analysis of the strontium oxide - strontium sulfate (SrO-SrS) water splitting cycle by applying the principles of the second law of thermodynamics and by utilizing the commercially available HSC Chemistry software. Initially, the thermodynamic equilibrium compositions allied with a) the thermal reduction of SrSO4, b) H-2 production via water splitting reaction (through SrO re-oxidation) are recognized. Moreover, the temperatures desirable for performing the thermal reduction and the water splitting steps are determined. The consequence of the molar flow rate of Ar on the thermal reduction of SrSO4 is also examined in detail. The effect of the thermal reduction and water splitting temperatures on the total solar energy input mandatory to run the cycle, re-radiation shortfalls from the cycle, heat energy emitted by the coolers and the water splitting reactor, and the cycle and the solar-to-fuel energy conversion efficiency (with heat recuperation) is scrutinized in detail. The attained outcomes specify that the cycle and the solar-to-fuel energy conversion efficiency up to 18.9 and 22.8% can be accomplished if the thermal reduction and the water splitting steps are conducted at 2380 and 1400 K (with 30% heat recuperation). (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.