Numerical analysis of multi-position PCM phase transition characteristics in a photovoltaic/thermal collector

The integration of thermal energy storage media utilizing phase transition mechanisms significantly enhances the operational performance of hybrid photovoltaic-thermal collectors through the cyclical storage and release of thermal energy during isothermal phase transitions. This study introduces a novel hybrid PV/T collector incorporating parallel-arranged phase change material (PCM) module. A computational framework integrating the finite difference method with an explicit enthalpy formulation was developed to analyze the melting characteristics of the PCM at multiple positions. The results demonstrate that under a solar irradiation of 823 W/m2, a uniform melting rate of 95% was achieved across all positions, despite a maximum phase transition initiation delay of 62 minutes. Notably, superior melting uniformity was also observed under lower ambient temperatures. Furthermore, the system configuration combining a 65 L tank with a flow rate of 0.036 L/s was identified as optimal, enabling a highly consistent 95% melting rate while reducing the maximum phase transition delay to 28 minutes. The analysis of these spatial-phase transition characteristics provides critical insights for the design of stable and efficient PV/T-PCM systems.