Numerical study on the impact of inclined fins and porosity on melting heat transfer in a phase change material-based thermal energy storage tank

Purpose The purpose of this paper is to numerically examine the influence of inclined fins and the porosity of porous media on the melting heat transfer of phase change material (PCM) in a latent heat thermal energy storage (LHTES) system. Design/methodology/approach Under the assumption of a constant inlet water rate, the alterations in fluid velocity within the bed as a result of temperature fluctuations during system operation were deemed negligible. To minimize computational time, steady-state water velocity distributions were used in combination with the heat transfer modeling techniques. The packed-bed, which includes microencapsulated PCM, is characterized as a porous medium with a defined porosity determined by the diameter of the PCM pellets. The fluid flow in the PCM packed-bed porous medium is governed by the partial differential equations based on the conservation laws of mass, momentum and energy. The computational fluid dynamics (CFD) model is developed and simulated using COMSOL Multiphysics software. The analysis extends the range of fin lengths (L = D/8 to 3D/4) and inclination angles (θ = π/6 to πp/6), while systematically examining variations in porosity (ε = 0.2 to 0.8). Findings It is observed that an increase in fin length enhances the fluid velocity near the tank axis, leading to a faster temperature rise in that region. Furthermore, an increase in fin length yields a nonuniform temperature distribution within the tank, resulting in different melting rates of PCM. The variation in the inclination angle of the fins primarily affects the melting rate of PCM at the base of the fins, with a slower melting rate observed for PCM within a narrower angle. The porosity governs the flow rate within the tank, whereby a higher porosity leads to a reduced flow rate and a more uniform temperature rise. Additionally, an increase in porosity diminishes the temperature disparity between different substances (fluid, PCM and porous medium) within the tank. Originality/value To the best of the authors’ knowledge, previous studies have not thoroughly investigated the combined effects of inclined fins, porous media and PCM on heat transport in a LHTES system. Therefore, the current work aims to investigate the influence of inclined fins and the porosity of porous media on the melting heat transfer of PCM in a unit. This study can contribute to enhancing the overall melting-solidification process of PCM in LHTES systems.