Numerical study of a latent heat thermal energy storage system enhanced by varying fin configurations

Abstract

This paper presents the results of a numerical study to investigate the effects of employing annular fins on the performance of a latent heat thermal energy storage (LHTES) system during the charging and discharging processes. The volume of the fins is kept constant for all the studied cases. The LHTES system consists of a cylindrical container filled with RT55 as the phase change material with a central pipe that passes through the container carrying the heat transfer fluid. The system was tested with no fins attached to the central pipe as the benchmark case. The fins were split into two categories: ten fins with a thickness of 1.587 mm and twenty fins with a thickness of 0.794 mm. These two categories were then subcategorized to uniform and variable fin lengths. The fin configuration that enhanced the charging process the most was twenty fins of variable length with long fins on the bottom of the pipe which resulted in a charge time decrease of 73.7%. For the discharging process, the optimal configuration was twenty fins with a uniform length which resulted in a time decrease of 79.2%. With respect to both charging and discharging time, the most effective configuration was the twenty-fin configuration with a uniform length which decreased the overall time by 76.3%.