Evaluation and Optimization of the Thermal Storage Performance of a Triplex-Tube Thermal Energy Storage System with V-Shaped Fins

Adding fins to a shell-and-tube phase change thermal storage is a simple and effective way to enhance the performance of the phase change heat storage unit, and the proper arrangement of the fins is essential to enhance the performance of the storage unit. To enhance the performance of the triplex-tube thermal storage unit, a novel V-shaped fin structure is presented in this paper. And the heat storage performance of the thermal storage system is studied by numerical simulation. Firstly, the performance of the triplex-tube thermal energy storage unit with different arrangements of V-shaped fins is investigated by a two-dimensional model and compared with the use of the traditional rectangular fin structure, and the optimal fin arrangement is derived. The results show that the V-shaped fins with the optimal arrangement can decrease the time for the PCM melting in the heat storage unit by 31.92% compared to the conventional rectangular fins. On this basis, the influence of fin angle and thickness on the heat storage unit was studied. Then, a three-dimensional model of the thermal storage unit was established. And the effect of the flow parameters (inlet temperature, inlet flow rate) of the heat transfer fluid (HTF) on its performance was discussed in detail. Finally, the stored energy analysis of the whole thermal storage unit is carried out.