Thermal performance analysis and optimization of a latent heat thermal energy storage device integrating with three-dimensional tree crown-like fins

The application of the latent heat thermal energy storage (LHTES) device is trapped by the low thermal conductivity of phase change materials. To this end, a type of three-dimensional bionic fin inspired by the tree crown is proposed in this research. Initially, the impacts of the trunk fin length (l1) and the branch fin inclination angle (alpha) on the melting process are considered. Subsequently, the influences of the fins layer rotation angle (delta) and the gradient fins layer pitch are examined. Eventually, the response surface method is employed to optimize the fin design. The results demonstrate that in comparison to the longitudinal fin, the tree crown-like fin achieves a reduction in the complete melting time by 61.4 %. The enhanced heat storage capacity is derived from using a lower l1 or a larger alpha. The promotional impact of increasing delta on accelerating the heat storage rate diminishes as the delta increases. The complete melting time of the LHTES device with a gradual shrinking fins layer pitch along the flow direction of heat transfer fluid is 5.7 % shorter than that of the LHTES device with a uniform fins layer pitch. After structural optimization, the LHTES device diminishes the complete melting time by 9.9 % compared to the original design.