Numerical modeling and analysis of the temperature effect on the performance of an alkaline water electrolysis system

Alkaline water electrolysis (AWE) is the most mature and reliable technology for producing green hydrogen among other types of water electrolysis. Although AWE has been developed over recent decades, both the capital and operational costs of AWE are still so high that hydrogen produced from AWE is economically less competitive compared with other hydrogen production technologies such as methane steam reforming. To reduce the operational cost of AWE hydrogen production, the AWE operations need to be optimized. In this study, to capture the temperature effect on the AWE system performance, AWE system model developed in our previous work has been simulated by varying the operating temperature. The simulation results present that higher operating temperature increases the system efficiency only in the relatively high current density region. The electrolyte flow rate required to maintain the temperature gradient throughout the AWE stack has been modeled as a polynomial equation based on the temperature and current density. When the temperature gradient throughout the AWE stack is reduced, the system efficiency is substantially increased. The model developed in this study can be used to find the optimal configuration and operating condition of the AWE system.