Effect of fin-metal foam structure on thermal energy storage: An experimental study

Thermal energy storage (TES) has been playing a crucial role in addressing the issue of solving the intermittent and random problems in solar energy utilization. The objective of this study is to squarely address and clarify the contribution of metal fin and foam to enhancing the phase change heat transfer by experiments. A novel hybrid fin-foam tube is proposed and its thermal performance is evaluated by experimentally comparing with other three competing structures including bare, fin, and metal foam tubes. A well-designed test rig is built and the energy storage features for the designed four TES tubes are analyzed by the complete melting time, melting front evolution, temperature variation and uniformity, and the temperature response rate. Results show that the fin-foam hybrid structure outperforms the other competing ones, demonstrating a reduction of 83.35% in complete melting time (compared with the bare tube). The transient temperature response is maximized by 529.1%. As for the single structure, both fins and metal foam can improve conductivity of phase change materials. The metal foam does a good favor to improve the uniformity of the temperature field inside the TES tube, but the fins weakened the uniformity. If the design target is temperature uniformity, adding metal foams other than fins can fulfil the task.