Numerical analysis and improvement of the thermal performance in a latent heat thermal energy storage device with spiderweb-like fins

Solidification enhancement is an essential topic for sustainable energy development. An innovative latent heat thermal energy storage (LHTES) device employing spiderweb-like fins is designed to improve solidification efficiency. The numerical solidification process of the current LHTES device is performed and compared to that with plate fins occupying an identical fin volume. Moreover, the solidification strengthening mechanism is revealed as well as the role of free convection in the heat release performance. Finally, the configuration of the spiderweb-like fin is improved, and the solidification efficiency of LHTES devices is evaluated. The results imply that the LHTES device with spiderweb-like fins improves the solidification performance by eliminating the heat transfer hysteresis zone. The dominant heat transfer mechanism of the solidification process shifts from convective heat transfer in the early stages to heat conduction in the later stages. More significantly, the free convection strengthens the solidification performance of the LHTES device with plate fins but has little effect on that with spiderweb-like fins. A spiderweb-like fin with the bifurcation number of 8 is suggested for maximizing the discharging performance. Compared to the plate fin, the full solidification time of the improved LHTES device with spiderweb-like fins is shortened by 47.9%, and its corresponding time-averaged heat release rate increases by 1.44 times.