Experimental Study on Melting and Solidification Cycle of a Hybrid Pin Fin/Metal Foam Energy Storage Tank

Phase change heat storage offers a practical solution to address the instability and intermittency of solar energy. However, the thermal conductivity of heat storage medium (phase change material) is low, which hinders its large-scale application. Metal foam and fins have proven effective in enhancing heat transfer performance. This study establishes a visual phase change heat storage experimental platform to compare the heat storage and release performances of four different structures: pure paraffin, fins, metal foam, and fin-metal foam, throughout the complete melting-solidification cycle. Experimental snapshots and real-time data acquisition are utilized to obtain phase interface changes and internal temperature variations at different time intervals, enabling a quantitative comparison of melting and solidification time and corresponding temperature responses. The findings reveal that both fins and metal foam effectively improve melting and solidification performance, with fins exhibiting more pronounced temperature responses, while metal foam demonstrates enhanced temperature uniformity. The comprehensive utilization of the fin-foam metal structure demonstrates the best heat storage/release performance. Compared to the pure phase change material (PCM) structure, heat storage and release time are reduced by 61.6% and 82%, respectively, while the average temperature response during the heat storage and release process improves by 122.4% and 429.8%.