Thermal characteristics of phase change heat storage process and waste heat recovery of hydrogen fuel cell: A numerical study

The utilization of waste heat recovery in fuel cells through heat storage can result in favorable energy efficiency gains and environmental advantages, while simultaneously improving the reliability of energy provision in photovoltaic systems. However, the low thermal conductivity of phase change materials dramatically hinders access to a safe, stable, and efficient renewable energy supply. To improve thermal efficiency, this paper proposes a novel triangle branch fin with straight, arc-curved, and corrugated shapes. Combined with metal nanoparticles, the heat transfer of phase change material is enhanced. A series of simulations are performed to judge the novel design based on fin shape and distribution based on the energy charging characteristics. The propagation of the melting front as well as the development of temperature and velocity during the entire process of melting are compared and analyzed. Results reveal that the straight triangle branch fin outperforms the other five cases with basic straight fin, corrugated fin, curved fin, arc-shaped fin, and corrugated branch fin regarding the melting performance, resulting in a 39.79 % reduction in melting time. The findings guide the evaluation and operation of heat storage tanks with fin enhancements.