(246d) Solar Thermochemical Hydrogen Production Efficiency with Kinetic Limitations

Overall production efficiency for solar thermochemical hydrogen production has been calculated for a generalized reactor system. This method uses cerium oxide as a well-studied example material, and is largely applicable to many materials for solar hydrogen production via a two-step thermochemical reduction-oxidation cycle. These calculations include steam heating requirements with gas-gas and solid-solid heat recuperation, pump work, and re-radiation losses at the solar receiver, as well as a discussion of the relative sensitivity of each of these factors. The efficiency calculation uses thermodynamic equilibrium states of the active material to determine the reactivity and production capacity, as well as a calculation of the required amount of water to drive the reaction at a particular set of conditions. Furthermore, kinetic limitations to efficiency are introduced to the efficiency calculation, which illustrate important factors for the determination of optimal operating conditions for the particular cycle, material, and operational parameters of interest.