Thermodynamic analysis of Ni-ferrite based solar thermochemical H2O splitting cycle for H2 production

In this paper, a comprehensive thermodynamic analysis of Ni-ferrite based H2O splitting cycle is performed using HSC Chemistry 7.1 software and its thermodynamic database. The influence of partial pressure of O-2(P-O2) in the inert N-2 and thermal reduction temperature (T-H) on delta (degree of nonstiochiometry) introduced in the Ni-ferrite crystal structure is investigated. With the increase in the P-O2 in the inert N-2 and T-H the delta increases, which results into higher levels of H-2 production via H2O splitting reaction. Variations in the other thermodynamic process parameters such as total amount of solar energy required to run the cycle ((Q) over dot(solar-cycle)), total amount of heat energy re-radiated from the cycle ((Q) over dot(re-rad-cycle)), amount of heat energy released by water splitting reactor ((Q) over dot(splitting-reactor)), cycle (eta(cycle)) and solar-to-fuel energy conversion efficiency (eta(solar-to-fuel)), and others as a function of P-O2 in the inert N-2, T-H, and water splitting temperature (T-L) are also researched. The eta(cycle) and eta(solar-to-fuel) upsurges with the reduction in the P-O2 in the inert N-2, T-H, and T-L. For instance, eta(cycle) = 29.5% and eta(solar-to-fuel) = 35.5% can be achieved at P-O2 in the inert N-2 = 10(-5) atm, T-H = 1600 K, T-L = 1000 K. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.