The effects of fin parameters on the solidification of PCMs in a fin-enhanced thermal energy storage system

In the present study, a triplex-tube, employing fin-enhanced phase change materials (PCMs), as a thermal energy storage (TES) system was studied numerically. The main flaw of the PCMs is their low thermal conductivity that restricts their effectiveness for energy storage applications. Metallic (copper) fins are added to the geometry of the system to improve their function by extending the heat transfer area. The effects of the presence, configuration, and dimensions of copper fins were investigated to understand the best design for minimizing the solidification time and achieving the best performance enhancement for the TES system selected for this study. The results revealed that the best performance belonged to fins with a mix configuration, with an attachment angle of 90◦ and the length and width of 28 mm and 1 mm, respectively. Using this configuration could reduce the required time for complete solidification by around 42% compared to the system without fins. Moreover, it was concluded that increasing the length of the fin could offer its positive effect for enhancing the performance of TES system up to an optimal point only while increasing the width showed a diverse influence. Furthermore, the angles between the tube surface and the fin direction were investigated and 90◦ was found to be the best choice for the TES case selected in this study. In addition, placement of the fins on the surface of internal or external tube or mix method did not show a significant effect while placing the fins on the external surface of the tube showed even a negative impact on the performance of the TES system compared with when no fins were applied.