A numerical investigation on the finned storage rotation effect on the phase change material melting process of latent heat thermal energy storage system

Abstract

Latent Heat Thermal Energy Storage (LHTES) is one of the most significant ways to mitigate solar energy intermittency using Phase Change Material (PCM). In the present study, a novel simultaneous utilization of longitudinal fins and storage rotation techniques to reduce the charging time and increase the amount of energy stored is considered in a double-pipe heat exchanger by developing a two-dimensional numerical model. Seven main cases have been defined, and finally, an optimal case with the least complete melting time has been introduced. The results indicated that embedding the fin on the lower half of the fixed storage accelerates the melting process. Rotating the finned storage can further reduce the melting time by up to 18.5 %, and embedded fins in rotating storage trap the melted PCM and reduce the complete melting time by 70 %. Finally, it is observed that simultaneous use of storage rotation and embedded longitudinal full-scale fins can achieve a 72 % reduction in complete melting time and a 115 % increase in total cumulative stored energy, which is related to the optimal case. The optimal case has four fins with an angle difference of 90° and two vertical stop steps with an angle of 180°.