Thermodynamic analysis of a solar-driven high-temperature steam electrolyzer for clean hydrogen production

Increasing world population and consequent increase in fossil fuels consumption emerge the necessity of looking for new sources of energy; resources that are clean, cheap, and renewable. Hydrogen is known as a clean and renewable fuel in various approaches; so, finding clean ways of hydrogen production can be considered as an appropriate solution for climate changes and global warming. In this study, a conceptual design of solar-driven high-temperature steam electrolyzer system is presented, and its performance is investigated thermodynamically using a real-time simulator in-house code. Evaluation of the effects of inlet parameters on the system performance is performed and the system real-time performance is calculated on design day at two different sites. Results show that the proposed system is able to separate 98% of existed hydrogen in the feed water and produce pure hydrogen with the rate of 1.2 g/s with overall energy and exergy efficiencies of 21.5% and 22.5% respectively. In addition, the main exergy destructor item is reported as the solar collector with 36.4% exergy degradation of inlet exergy. Based on the results, it was deduced that the most effective parameters on heat absorption are direct normal irradiance and incidence angle while relative humidity has no major effect. Furthermore, the designed system produced 52.43kg and 26.45kg hydrogen on the design day at Sterling and Babol Noshirvani University of Technology sites. The mean annual hydrogen production for these sites were estimated 4.98 and 3.93 tons, respectively.