Melting heat transfer characteristics and multi-objective optimization of phase change material coupled with copper foam and biomimetic tree-shaped fins

To address the bottleneck of slow charging/discharging rates in latent thermal energy storage (TES) systems caused by the inherently low thermal conductivity of organic phase change materials (PCMs), this paper proposes a novel composite TES unit integrating copper foam with biomimetic tree-shaped fins. A numerical simulation approach is employed to systematically investigate the effects of fin configuration, copper foam porosity, heating temperature, and fin material on melting heat transfer characteristics. The results demonstrate that the tree-shaped fin coupled with copper foam structure increases heat storage capacity by 175.6 % and reduces complete melting time by 89.1 % compared to the conventional fin structure. Decreasing copper foam porosity accelerates melting but reduces PCM filling volume, with an optimal porosity range around 0.875 identified. Increasing heating temperature significantly enhances the heat transfer driving force, reducing melting time by 29.6 % at 373 K compared to 353 K. Aluminum is selected as the fin material due to its comparable thermal performance to copper at significantly lower cost and weight penalties. Response surface analysis reveals that temperature exhibits a dominant main effect on heat storage capacity, while temperature and porosity demonstrate significant effects on complete melting time. The findings of this study provide theoretical guidance and data support for the structural design and parameter optimization of high-efficiency TES units.