Photovoltaic modules lose efficiency when exposed to high temperatures, a challenge that passive cooling technologies can mitigate. Researchers conducted a comprehensive numerical study of phase change material (PCM) heat sinks integrated with solar panels at various mounting angles to identify optimal thermal management strategies.
The investigation examined nine distinct configurations—six multilayer arrangements and three single-material reference cases—using gallium, calcium chloride hexahydrate, and commercial PCM RT35HC. Simulations covered five inclination angles from horizontal to vertical during a seven-hour heating cycle under intense solar irradiance equivalent to 1000 watts per square meter. Advanced computational fluid dynamics modeling with the enthalpy-porosity method tracked phase transition dynamics and natural convection effects within the PCM layers.
Results revealed that PCM material selection and mounting angle substantially outweigh the benefits of multilayer configuration complexity. Pure gallium maintained the most stable thermal performance across all angles, consistently delivering 11.89–11.96% electrical efficiency. However, gallium's high cost limits practical deployment. Among multilayer designs, performance varied by inclination: horizontal installations favored one arrangement, while vertical systems performed best with different layer sequences.
RT35HC, a lower-cost commercial PCM, demonstrated remarkable inclination sensitivity. At horizontal or shallow angles, its efficiency remained minimal (0.29–1.10%), but performance jumped dramatically to 11.3–11.34% at steep angles exceeding 75 degrees. This dramatic improvement stems from enhanced natural convection currents at steeper inclinations, which redistribute heat more effectively through the PCM during melting cycles.
The economic analysis proved decisive: gallium-based systems become economically unviable as price ratios increase relative to RT35HC, while RT35HC emerges as the superior cost-performance choice for rooftop installations. The study underscores that optimal PV-PCM design demands simultaneous optimization across thermal physics, material selection, installation geometry, PCM volume, and cost constraints. These insights guide engineers toward practical passive cooling solutions tailored to regional solar conditions and budget constraints.
