Performance enhancement of PV-PCM systems with semi-elliptic cavities at different tilt angles

Abstract

In this study, a new passive cooling approach is proposed to enhance the thermal, electrical, and overall performance of photovoltaic modules by integrating phase change materials (PCM) into engineered semi-elliptical cavities. A two-dimensional transient numerical analysis was carried out using ANSYS Fluent 25.2 and the enthalpy-porosity method to model PCM melting and natural convection. Two cavity geometries, an elongated semi-elliptical shape and a wide semi-elliptical shape, were analyzed at tilt angles of 10°, 20°, 30°, 40°, 50°, and 60° to evaluate their influence on heat transfer and PV performance. The findings show that PCM melting behaviour depends strongly on cavity shape and inclination. At low tilt angles, heat transfer inside the PCM is mainly conduction-driven, while at higher angles convection becomes dominant due to increased buoyancy effects generated by the cavity configuration. The elongated cavity at a tilt angle of 60° demonstrated the most effective thermal regulation, lowering the PV module temperature from 342.9 K at 10° to 328.8 K at 60°, corresponding to a temperature reduction of 14.1 K, which represents approximately a 4.1% decrease, while increasing the PCM liquid fraction by 26.8%. This enhancement in thermal management led to an increase in electrical and thermal efficiencies of 7.98 % and 6.42 %, respectively, resulting in an overall performance improvement of 7.1 % compared to the least efficient cavity configuration.