Enhancing the energy discharging performance by novel V-shaped branch fins in a triple-tube latent heat storage unit

To enhance the energy discharging performance of the triple-tube latent heat storage unit (TTLHSU), this paper introduces a novel two-stage V-shaped branch fin design to uniform the heat transfer from different radial regions, and its transient solidification model is established and numerically simulated. The solidification process under the novel V-shaped branch fins is compared with that under straight fins based on phase interface/temperature distribution diagrams, liquid fraction, and temperature gradient curves. The sole impacts of three structural parameters (branch/base width ratio, branch angle, and branch/base length ratio) of the V-shaped branch fins on solidification are investigated. The optimized fin structure is obtained using the response surface methodology (RSM). The results indicate that the V-shaped branch fins promote solidification by synchronizing the radial rates. Structural parameters primarily affect the evolution of phase interfaces, the most largely with the length ratio, followed by the branch angle and then the width ratio. Smaller branch/base length and/or width ratios lead to shorter solidification times and faster heat release rates. As the branch angle increases, the solidification time decreases initially and then increases, and correspondingly, the heat release rate varies reversely. The optimized V-shaped fin structure has a branch angle of 44° and a branch/base length/width ratio of 0.5, reducing the solidification time by 64.2 % and enhancing the heat release rate by 186.2 % from those of straight fins. The results of this study could guide for using fins to improve the energy-discharging performance of TTLHSU. •A novel V-shaped branch fins is proposed to enhance energy discharging of triple-tube latent heat storage unit.•Adding four V-shaped branch fins could perfectly synchronize the heat transfer of the difficult-to-solidify region.•The extend of influence to the solidification performance depends on the structural parameters of the adjustment.•The optimized V-shaped branch fins could give the best energy discharging performance.