Solar energy conversion to hydrogen by water splitting is a promising technique because it is sustainable and environmentally friendly. One option for water splitting is through thermochemical cycles in which one of the steps is electrolytic or photocatalytic. In this paper, the economics of a thermochemical process that combines photocatalysis, photovoltaics, high temperature thermal energy and energy storage to harvest solar energy is assessed. This paper focuses on the standard hybrid sulfur ammonia thermochemical cycle (SA) in which the electrolytic step of the hydrogen production from ammonium sulfite solution is augmented by a photocatalytic step. Trying to make use of most of solar radiation we use beam splitter to separate solar radiation to wave length less than 520 nm, between 520 to 800 nm and to more than 800 nm. The spectrum less than 520 nm is used to run a photocatalytic hydrogen production unit. The spectrum between 520 to 800 nm is used to generate electricity through photovoltaic cells which is used to run electrolytic hydrogen production unit. The spectrum greater than 800 nm is used to satisfy the heat requirements of the thermochemical plant. We investigate the economic advantage of replacing the sulfate or sulfuric acid decomposition step by reaction with cuprous oxide to produce cupric oxide which is then decomposed to cuprous oxide and oxygen at high temperature.
Soliman, Moustafa A.; Abomosalam, Abdel Moniem; Shedid, Noran; Othman, Mohamed; Hatem, Toka; and Samer, Marc, "Analysis of a Solar Hybrid Sulfur Ammonia Copper Oxide Thermochemical Cycle for Hydrogen Production" (2021). Chemical Engineering. 135.