Experimental evaluation of thermal pad design parameters for enhanced PV module temperature homogeneity and efficiency

This study presents a passive cooling method for solar photovoltaic (PV) panels using carbon based thermal interface materials (TIMs) referred to as CSF series (carbon based soft film) applied to the rear surface of the solar panels. The aim is to reduce the panel temperature and enhance the energy efficiency under real operating conditions by finding the optimal thermal conductivity and thickness of the thermal pads. Numerous thermal pad materials having a range of thermal conductivities (15, 20, 25, 30, 35, and 40 W/mK) and thicknesses (1–5 mm) were tested to assess their impact on the heat dissipation of the PV panels. The cooling performance was quantified using temperature drop (ΔT) measured by infrared thermal imaging under outdoor conditions. The results offer valuable insights into the practical application of thermal interface materials for improving the thermal management of photovoltaic systems. The optimal TIM configuration (CSF-40 with 3 mm thickness) yielded a maximum temperature reduction of 9.2 °C (≈ corresponding to an estimated efficiency improvement of approximately 4%); however, cooling improvements begin to diminish beyond ∼25 W/m·K and saturate near 30 W/m·K due to interfacial and convective limitations. A pad thickness of 3 mm emerged as optimal across all CSF grades, offering the best trade-off between conductive efficiency and material resistance. Power-law models (ΔT = a·kᵇ) were used to quantify the nonlinear relationship between thermal conductivity and cooling performance, providing empirical correlations for for estimating cooling performance within the investigated parameter range. This work also offers an extended outdoor assessments of carbon-based TIMs in PV cooling and sets out conductivity-thickness design guidelines for the investigated TIM configurations. These findings demonstrate the practical applicability of carbon-based TIMs for improving PV module efficiency through enhanced panel's temperature.