Study on solidification performance of PCM by longitudinal triangular fins in a triplex-tube thermal energy storage system

Phase change materials have important significance for thermal energy storage, but their low heat conductivity is the main problem affecting energy storage. In order to improve the solidification performance of the triplex-tube thermal energy storage system, a new type of triangular fin is proposed in this paper. Firstly, longitudinal triangular fins with different distributions are added to the triplex-tube thermal energy storage system to compare the solidification performance with that of traditional rectangular fin. The solid distribution and temperature evolution of the fins with different distributions were studied by numerical simulation in detail. Compared with the traditional rectangular fin, the solidification time of the system can be reduced by up to 30.98% by the optimized triangular fin. Secondly, the temperature evolution law of different positions in this system is emphatically studied, so as to prove the optimization degree of the fin to the solidification behavior of the energy storage system. Then the influence of the geometry parameters, triangular fin airfoil, the temperature of the tube cooling fluid on the solidification performance are discussed. Finally, the effect of the connecting position between the new triangular fin to the inner or outer tubes on the solidification performance of the system is discussed. •Innovative triangular fin is proposed to improve TTES system solidification performance.•Solid phase and temperature evolution of the system are studied by numerical simulation.•The ternary mixed molten salts of Li2CO3−K2CO3−Na2CO3(32−35−33wt%) is used as PCM.