The effect of temperature variation of water on melting of PCM inside latent heat energy storage

This study presents a numerical investigation into the melting dynamics of a Phase Change Material (PCM) within a shell-and-tube Latent Heat Thermal Energy Storage (LHTES) system, the primary objective was to elucidate the effect of varying the rate of temperature change, controlled via two key operational parameters: the Heat Transfer Fluid (HTF) inlet temperature and its volumetric flow rate, a three-dimensional computational fluid dynamics (CFD) model was developed and solved using the enthalpy-porosity method in ANSYS-Fluent, the results demonstrate that both parameters significantly influence the energy charging (melting) performance, increasing the HTF flow rate from 2 L/min to 4 L/min accelerated the melting process by enhancing the convective heat transfer coefficient at the fluid-wall interface. However, the HTF inlet temperature was identified as the dominant factor, elevating the HTF temperature from 343 K to 353 K drastically reduced the total melting time from approximately 150 minutes to 110 minutes under a 4 L/min flow rate, this profound acceleration is attributed to the combined effect of a larger thermal gradient and, more critically, the intensification of buoyancy-driven natural convection currents within the molten PCM, the study concludes that for optimizing the melting rate, controlling the HTF inlet temperature is the most effective strategy.