Numerical modeling and parametric analysis of a phase change material–based thermal energy storage unit

Phase change materials (PCMs) are widely used in thermal energy storage (TES) systems because of their high latent heat storage capacity, although their low thermal conductivity often limits performance. This study presents a MATLAB-based numerical investigation of PCM melting using a finite volume method coupled with an enthalpy–porosity formulation to model phase change and natural convection. The numerical model is validated against benchmark solutions from the literature, showing good agreement in liquid fraction evolution and Nusselt number predictions. A parametric analysis evaluates the effects of heat source temperature, PCM thickness, convective heat transfer coefficient, and thermal conductivity enhancement. Results show that increasing heat source temperature and thermal conductivity accelerates melting, whereas increasing PCM thickness delays the process. Thermal conductivity enhancement reduces melting time by up to 40%, while combined optimization achieves reductions of up to 55%. These findings provide practical guidance for optimizing PCM-based thermal energy storage systems.