Performance optimization of a finned shell-and-tube ice storage unit

Abstract

The solidification enhancement of the finned shell-and-tube ice storage (STIS) unit with water is numerically analysed with consideration of natural convection. An unsteady model of the discharging process is presented to investigate the role of fin geometry in ice storage performance, which is validated by a discharging experiment in a finned STIS unit. The temperature response and ice front evolution in a finned STIS unit are analysed and compared with a corresponding unit without fins. The effects of structural parameters on the solidification performance are comprehensively discussed, including fin height, fin thickness, and fin number. Furthermore, a new evaluation criterion of the dimensionless cooling power mass penalty is proposed to optimize fin geometry. The results indicate that the natural convection is not conducive to the solidification performance. The addition of fins effectively enhances the energy discharging performance of STIS units due to the coupling effect of natural convection suppression and thermal conduction enhancement. It is highly efficient to increase fin height for better energy discharging performance since fin height is the most important parameter. Fin thickness and fin number also affect ice storage performance. Considering the trade-off between the weight and ice storage performance of STIS units, the optimal fin thickness and fin number in this paper are respectively recommended to be 3 mm and 8 to achieve the largest performance enhancement with the least mass penalty.