Analysis of melting and solidification performance of bionic snowflake fin horizontal Triplex-tube latent heat storage system based on response surface method

For the low thermal conductivity of phase change materials and other characteristics, a crossed snowflake fin Triplex-tube thermal energy storage (TTES) is proposed, and the analysis of melting and solidification of phase change material (PCM) by applying the numerical simulation method in the comprehensive thermal performance study. The three-casing phase change heat storage unit filled with RT55 is the object of this paper, and firstly, the cross distribution of snowflake fins into 8 fins is studied, and in the analysis of the thermal performance of TTES, the integrated heat storage (release) time, heat storage (release) and heat storage (release) temperature are used as evaluation indicators. By investigating the melting and solidification properties of PCM, the bifurcation angle of the best thermal performance is 60°, and the best fin profile is obtained by reasonable simplification for the purpose of maximum heat storage. The response surface method (RSM) is then used to optimize the size structure of the fins for the purpose of maximum melting heat storage and maximum solidification heat release of TTES, and the heat function equations of the melting and solidification processes of PCM are fitted, and the optimal regions of the melting and solidification processes of TTES are obtained. Finally, the optimization results show that when the length of the fin is 11 mm and the width of the fin is 0.8 mm, TTES has the best overall thermal performance. Compared with before optimization, the heat of PCM melting accumulation increased by 3.92 kJ and the heat of PCM solidification exotherm increased by 5.773 kJ. •A new type of crossed snowflake fin is proposed to be used in the Triplex-tube latent heat system.•The optimal thermal storage performance and solidification performance of TTES are that the bifurcation angle is 60°.•The best thermal performance can be obtained by reasonably simplifying the upper half fin.•Comprehensive optimization of heat storage and solidification by response surface method