Improving the energy release of a latent heat storage with multiple phase change materials loading and partition shaping

This paper presents a theoretical study of the integration of two selected phase change materials (PCMs) into a vertical shell and tube latent-heat thermal energy storage unit. Various cell shapes and PCM arrangements are analyzed for their heat release characteristics and compared to a reference unit. Using the finite volume method with an enthalpy-porosity formulation, the study simulates conjugate heat transfer between an isothermal wall and PCMs. This approach examines the impact of both the delay of the phase transition and the layout of the PCM cavities on natural convection. The findings indicate that these factors have a significant influence on energy transport. Delaying the solidification process near the cold wall can lead to a substantial reduction in the phase transition time. Furthermore, triangular cross-section cells improve convection and increase the solidification and complete energy discharge times by 42.7% and 25.3%, respectively. The energy charging performance is also enhanced by 39.7%.