Optimization of Fin Arrangement in a Double-Pipe Heat Exchanger to Improve the Storage Performance of Phase Change Materials

Using latent heat storage systems with phase change materials (PCM) is an effective way to store thermal energy, which has been of great interest recently. Using fins is one of the simplest and cheapest ways to increase heat transfer in PCMs and increase the performance of the storage system. Since the fin arrangement has a significant impact on the charging time of the PCM, the main goal of this study is to optimize the fin arrangement in the PCM chamber in a double-pipe heat exchanger in order to decrease the charging time, and thus increase the efficiency of the storage system. For this purpose, the governing equations including conservation of mass, momentum, and energy in a finned double-pipe heat exchanger have been solved using ANSYS-Fluent software to investigate the dynamic behavior of PCM. The thermal-hydraulic performance of PCM at different configurations has been fully analyzed by drawing liquid fraction contours, velocity vectors and streamlines. Also, to find the optimal fin arrangement and maximize the storage performance, the response surface method based on the central composite design have been implemented. The results obtained from the response surface with the reduced cubic equaltion show that compared to the case without fins, the charging time reduces by about 19% using the uniform fin configuration, while reduces about 56% using the optimal fins arrangement, which is a significant amount.