Development of a Solar-Thermal-Driven Hydrogen Production Cycle Based on the Zn–H₂O Reaction and ZnO Redox Process

Aiming to establish a sustainable hydrogen production technology using solar thermal energy, this study constructed a reaction system based on the reduction cycle of zinc oxide. Sunlight was concentrated with a Fresnel lens and used as the primary heat source for the reaction system. Zinc oxide was reduced to zinc by adding carbon and heating it at high temperatures. The generated zinc was then reacted with water to produce hydrogen. In this study, experiments were conducted under atmospheric pressure instead of vacuum conditions to evaluate the system's reactivity and hydrogen generation efficiency. Additionally, simulated experiments were performed indoors using an electric furnace.