A numerical investigation of the effect of fin inclination angle on the thermal energy storage performance of a phase change material in a rectangular latent heat thermal energy storage unit

In a numerical investigation of the thermal energy storage performance of a latent heat thermal energy storage system with three angled fins, the enthalpy-porosity model was used to simulate the phase-change process. To analyze the effect of the angle of inclination of the fin (θ_f) on the heat transfer characteristics and energy storage performance, a parametric study was performed in which θ_f was varied over the range −40^∘≤θ_f≤40^∘. The variation in energy storage performance according to fin angle is also analysed, in order to obtain an optimal fin angle for maximum energy storage performance for the geometric shape of interest. The results reveal that both the heat transfer characteristics and the energy storage performance are affected significantly by variations in θ_f. For cases where the fins are angled downwards, the upward flow is hampered, and where the fins are angled upwards, natural convection is intensified prior to the onset of thermal stratification. During the final stage of the charging process, the quantity of the remaining solid phase change material in the lower region increases, which delays the melting time. In order to evaluate the energy storage performance, the melting time, the total stored energy, and the mean power were calculated. For θ_f in the range −30^∘≤θ_f≤−10^∘, the energy storage performance can exceed that for the case of θ_f=0^∘. The case of θ_f=−20^∘ shows the best thermal energy storage performance as the average power is up to 19.3% higher than that for the case of θ_f=0^∘ among all cases considered in present study.