Enhancing the energy storage/release performance of a triple-tube phase change storage unit with novel claw-shaped fins

A novel claw-shaped fin has been developed to address the heat-transfer differences between the melting and solidification processes to enhance the efficiency of the melting/solidification cycles. The enthalpy-porous medium model simulated the phase change material's (PCM) melting and solidification process. The impact of branch number, length ratio (L), branch angle (α), and fin material on the PCM phase change process was analyzed utilizing liquid fraction/temperature contours, liquid fraction curves, and Nusselt numbers. Results indicate that the improvement in melting performance due to adding branches is primarily attributed to enhanced heat conduction and coordinates the radial solidification rate by improving the radial temperature response. For a fixed fin volume, increasing L and decreasing α are beneficial for reducing the PCM's melting and solidification times. Materials with lower thermal conductivity can weaken the ability of heat to transfer quickly from the fin base to the branches, thereby reducing the effectiveness of direct heat transfer to the PCM. Based on RSM, the L significantly impacts melting/solidification performance more than the α; the optimized four-branch fins (L = 1.7, α = 21.6°) reduce the melting/solidification time by 47.8 % compared to V-shaped fins. Further increasing branches does not significantly enhance heat-transfer performance.