Effect Of Tube Orientation And Flow Rate On Phase Change Material Solidification Performance

Abstract

Latent Heat Thermal Energy Storage (LHTES) systems utilizing Phase Change Materials (PCMs) offer a promising solution for managing energy supply and demand discrepancies, this study numerically investigates the solidification (energy discharge) performance of a PCM within a shell-and-tube LHTES unit, focusing on the impact of Heat Transfer Fluid (HTF) flow rate and the orientation of an inner semi-circular heat transfer tube, using ANSYS-Fluent, the enthalpy-porosity method was employed to model the phase change process, simulations were conducted at HTF flow rates of 2 L/min and 4 L/min, with the inner tube oriented in "TOP," "LEFT," "RIGHT," and "BOTTOM" configurations, results consistently showed that increasing the HTF flow rate significantly accelerated the solidification process and reduced the total discharge time due to enhanced convective heat transfer, tube orientation also demonstrated a considerable influence; "TOP" and "LEFT" orientations generally exhibited faster cooling rates and shorter solidification times compared to "BOTTOM" and "RIGHT" orientations under identical flow conditions, this is attributed to the effect of orientation on the formation of the solid PCM layer and residual natural convection patterns, which collectively impact heat extraction efficiency, the findings underscore the importance of optimizing both HTF flow rate and heat exchanger tube orientation for enhancing the discharge performance of LHTES systems.