Heat Transfer Analysis of a Solid-Solid Heat Recuperation System for Solar-Driven Non-Stoichiometric Redox Cycles

Heat transfer is analyzed numerically for a solid-solid heat recuperation system employed in a novel directly-irradiated solar thermochemical reactor realizing a metal oxide based non-stoichiometric 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 modes is developed to predict temperatures of both components, rates of heat transfer, and the effectiveness of heat recuperation. 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.