Pinch analysis for recycling thermal energy in the Cu–Cl cycle

Due to lower temperature requirements than other thermochemical cycles, the copper-chlorine (Cu–Cl) cycle is one of the most promising cycles for hydrogen production. The cycle consists of a number of endothermic and exothermic processes. The overall efficiency of the cycle can be improved by recovering as much heat as possible from the exothermic processes within the cycle and minimizing the net heat input to the cycle. In this paper, a pinch methodology is used to determine the minimum energy requirement for the overall Cu–Cl cycle, if heat recovery within the cycle is optimized. All heating and cooling flows (actual or potential) are presented as temperature-energy flow profiles and combined into composite curves for the entire cycle. Additional equipment and the overall thermal layout of the cycle are also investigated.