Heat transfer analysis of a solid-solid heat recuperation system for solar-driven nonstoichiometric redox cycles

Heat transfer is predicted for a solid-solid heat recuperation system employed in a novel directly-irradiated solar thermochemical reactor realizing a metal oxide based nonstoichiometric redox cycle for production of synthesis gas from water and carbon dioxide. The system is designed for continuous operation with heat recuperation from a rotating hollow cylinder of a porous reactive material to a counter-rotating inert solid cylinder via radiative transfer. A transient heat transfer model coupling conduction, convection, and radiation heat transfer predicts temperatures, rates of heat transfer, and the effectiveness of heat recovery. Heat recovery effectiveness of over 50% is attained within a parametric study of geometric and material parameters corresponding to the design of a two-step solar thermochemical reactor.