Experimental and numerical investigations on the thermal performance enhancement of a latent heat thermal energy storage unit with several novel snowflake fins

This article introduces a novel snowflake fin inspired by the crystal structure of snowflake to enhance the heat transfer performance of Latent Heat Thermal Energy Storage (LHTES) units. Initially, a numerical simulation model for transient heat transfer units with snowflake fin was established in a shell and tube LHTES unit. The accuracy and dependability of the model are verified through comparison with experimental results. Then, the effects of three placement methods of LHTES unit (vertical, horizontal-Ⅰ, and horizontal-Ⅱ) on melting and solidification performance are explored. Additionally, the effects of traditional longitudinal fins, snowflake fin, and four novel snowflake fins on melting and solidification behaviors are quantitatively compared. The single-factor method and response surface methodology (RSM) were employed to further optimize the selected optimal novel snowflake fin design. The research results show that the heat transfer performance of the vertically placed LHTES unit is the best. In comparison to traditional longitudinal fins and conventional snowflake fin designs, the novel snowflake fin design reduced the total melting and solidification time by 45.15% and 18.14%, respectively. The optimal size of the branch fins is a radial length of the root of 22.9 mm, self-length of 8 mm, and an angle of 60.3°.