High-temperature hydrogen production by solar thermochemical reactors, metal interfaces, and nanofluid cooling

Abstract

Solar thermochemical reactors have been considered in recent studies because of converting the solar energy to a fuel, which is called solar fuel. In such reactors, heat transfer is a dominant phenomenon in generating products. Providing the optimum thermal energy for the solar thermochemical cycle can be gained by adjusting the size of the solar concentrator. In this study, the sizing of the solar concentrator is studied and the best size of the cavity is calculated by the Monte Carlo method. In this reactor using solar energy, the intermediate metal is converted to solar fuel. ZnO/Zn is considered to be the intermediate metal for the reaction. Next, the solar reactor is modeled in three dimensions and all types of heat transfer mechanisms, i.e., conduction, convection, and radiation along with chemical reaction conditions, are also considered. Sensitivity analysis is done based on the solar concentrator size and the aperture cavity. The results show that the optimum size of the dish collector is 5.168 m and the aperture cavity diameter was gained 5 cm for 10 kWth solar reactor. Nanofluid is used as cooling fluid, with the best modeled fluid flow rate for this structure, the ratio of annual fluid flow to nanofluid being 1. By examining the hydrogen production reactor, the amount of hydrogen produced in the system is 34 mol m−3. Also, the irradiation distribution of the cavity receiver and the temperature distribution of the solar reactor were modeled and analyzed.