Effect of orientation on thermal performance of a latent heat storage system equipped with annular fins – An experimental and numerical investigation

Abstract

Because of high energy storage density, latent heat storage is preferred over other thermal energy storage methods. The most common configuration of latent heat storage unit is shell and tube configuration, the performance of which greatly depends on its orientation. The influence of orientation may get altered when fins are provided for heat transfer enhancement. Hence, the current work is intended to examine the performance of a shell and tube latent heat storage unit in which annular fins are attached to the tube. Both experimental and numerical investigations are carried out to get a thorough insight into the melting behavior. The experiments are conducted at 0°, 30°, 60° and 90° inclinations (0° corresponds to vertical configuration); both energy and exergy analyses are carried out. The findings revealed that the melting rate is nearly same at all the inclinations during the initial stages. Later with the progression of time, the melting rate is decreased and the decrement is more for horizontal configuration. 85.63% more time is required for complete melting at 90° inclination (horizontal) in comparison with the 0° inclination. This is because of the suppression of convective transport in the bottom half for the case of horizontal orientation. Higher energy efficiency is obtained for horizontal orientation, whereas vertical orientation exhibited higher exergy efficiency. Energy stored, average Nusselt number and effectiveness of the latent heat storage system are also higher for 0° inclination.