Assessment of Fin Thickness Influence on Melting and Solidification Processes Inside Longitudinally Finned Latent Thermal Energy Storage
Abstract
In the paper, series of numerical investigations have been performed in order to evaluate the influence of fin thickness on melting and solidification performance inside the shell-and-tube type longitudinally finned latent thermal energy storage (LTES). The LTES uses water as the heat transfer fluid (HTF) and RT 25 paraffin as the phase change material (PCM). Using experimentally validated mathematical model and numerical procedure, numerical investigations of PCM melting and solidification have been carried out for various fin thicknesses; 0.5 mm, 2 mm and 4 mm. Thermal energy stored in 8 h of charging, during which the PCM melts, and released in 12 h of discharging, during which the PCM solidifies, as well as melting and solidification rates, were compared. Time-wise variations of average liquid fractions and fin temperatures have been obtained for all configurations during melting and solidification processes. The results indicate that, due to increased fin capacity, thicker fins expedite melting/solidification rate. However, due to reduced amount of the PCM as the result of using thicker fins, less thermal energy can be stored in and released from the LTES. As indicated by the investigation, fin thickness is an influential geometry parameter which should be carefully selected in order to maximize the LTES thermal performance.