Simulation of Hydrogen Production by Using Concentrated Solar Energy Through Thermo-Chemical Water Splitting Process: Part I—Simulation of Zinc Oxide Reduction Reaction

Due to the depleting reserves of fossil fuels and their harmful effects on the environment, there is an urgent need to explore clean alternative energy resources to fulfil the growing energy demand. Sunlight is an abundant source of energy, and its storage and utilization in the form of hydrogen is considered to be effective and cleanest. The present research is focused on the numerical investigation of hydrogen production through thermo-chemical decomposition of water. In this paper we report on the first step reaction which is the endothermic reduction of zinc oxide in a solar reactor/receiver coupled with a parabolic dish type solar energy concentrator. The simulations were conducted in a three-dimensional reactor model using the commercial CFD software FLUENT. The results of parametric study showed an increase in the fractional conversion of zinc oxide with a decrease in the diameter of the zinc oxide particles, while this fractional conversion decreased with a decrease in the zinc oxide mass flow rate. It was also observed that the particle initial temperature has no effect on the fractional conversion of the zinc oxide. The outlet temperature of the fluid mixture was also not influenced significantly by the zinc oxide fractional conversation and remained over 1800K for the entire fractional conversion range of zinc oxide.