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

•Numerical investigation on the thermal energy storage performance of vertical LHTES according to the fin angles (θf).•The results reveal that both the heat transfer characteristics and the energy storage performance are affected significantly by variations in θf.•For θf in the range −30∘≤θf≤−10∘, the energy storage performance can exceed that for the case of θf=0∘.•The case of θf=−20∘ shows the best performance among all the cases considered in the present study.