Thermal performance analysis of passive cooling for a photovoltaic module using an artificial heat source

Abstract Photovoltaic modules (PVMs) are susceptible to temperature fluctuations, where elevated operating temperatures decrease efficiency and accelerate degradation. While passive cooling systems such as heat pipes offer a promising solution, most previous studies have focused on conventional wick structures and filling ratios, with limited exploration of alternative wick materials for PV applications. This study evaluates the thermal performance of a passive cooling system utilizing a copper heat pipe (9.5 mm diameter, 450 mm length) equipped with fins at the condenser, heated by an electric heater as an artificial source. The pipe was wicked with carbon fiber and charged with distilled water at 60% of its volume. Temperatures at the evaporator, condenser, and surrounding air were measured to determine thermal resistance and heat absorption. The results showed that the evaporator temperature strongly influenced performance: lower temperatures increased resistance and reduced absorption, while higher temperatures decreased resistance and enhanced heat transfer. The system operated effectively over 30–85 °C, absorbing 1–66 W, with thermal resistance ranging from 0.0145 to 0.4333 °C/W. Compared to conventional wick structures, the carbon fiber wick provided faster heat spreading and lower resistance. The novelty of this work lies in integrating a carbon fiber wick with an optimized filling ratio, a configuration rarely addressed in PV cooling research. This study contributes a simple yet efficient passive design that is low-cost, lightweight, and easily integrated with commercial PVMs. Practically, the system requires no external power and can help maintain lower module temperatures, thereby improving conversion efficiency and extending the operational lifespan of PV installations in high-temperature environments.