Improvement of melting performance in a longitudinal finned latent heat thermal energy storage unit

This article presents an analysis and enhancement of the charging behavior of a double-pipe LHTES unit with longitudinal fins for concentrated solar power applications using a finite element numerical analysis approach. The finite element approach is applied to this numerical analysis by using "COMSOL Multiphysics" software. The investigated LHTES system has an operating temperature range of 180 degrees C-300 degrees C and uses "DelcoTerm Solar E 15" as the heat transfer fluid (HTF) with a eutectic inorganic mixture of sodium nitrite and sodium nitrate as the phase change material (PCM). While also taking into account the impact of the tube material and the number of fins, the primary goal of this study is to evaluate performance improvement by changing the thickness and number of fins in a linked manner without changing the storage unit capacity. The results show a maximal impact on thermal performance which decreased the melting time by 46% and the charging time by 49.6% for the configuration with a fin thickness of 1 mm, 27 longitudinal fins, an inner tube made of aluminum, and a mass flow rate of 60 kg/h.