Facile numerical approximations to evaluate the performance of an ice-on-coil-type latent thermal energy storage tank with top-inlet–bottom-outlet configuration

Abstract

In this study, different numerical approximations were compared to evaluate the performance of a top-inlet–bottom-outlet latent thermal energy storage (LTES) system, and to achieve a higher accuracy while reducing the computational time. The ice-on-coil-type LTES tank comprised of a heat exchanger with multiple horizontal copper tubes to separate the brine solution inside the tube and a phase change material—water—outside the tube. In the approximations, the tubes were arranged in parallel or series along the height of the LTES tank, which considerably affected the overall computational time with a weaker impact on the accuracy of calculation. Furthermore, instead of considering all the tubes, sample and interpolation (SI) method was used to reduce the calculation time. Three-dimensional (3D) and two-dimensional (2D) analyses were performed using numerical approximations on multiple tube arrangements in a flow pass of the heat transfer fluid. The results revealed that the U-bend zone significantly affected the accuracy of the results. Additionally, for the 2D analysis of straight tubes and 3D analysis of U-bend zone with the SI method, the numerical approximation yielded the optimal approximation, reducing the computational time approximately by a factor of eight compared with the 3D analysis of straight tubes with parallel arrangements.

Keywords

• Phase change material
• Tube arrangement
• Latent thermal energy storage tank
• Charging
• Discharging