Thermal management of photovoltaic panel using thermally conductive epoxy-based coating

Abstract

The rapid expansion of solar photovoltaic (PV) deployment in hot and humid regions such as Southeast Asia presents significant thermal-management challenges, as operating temperatures commonly reach 60-70 °C and accelerate material degradation, reduce efficiency, and shorten module lifetime. Existing cooling technologies-including active liquid circulation and passive approaches such as PCM-filled metallic tubes, hygroscopic hydrogel backplates, aluminum fins, and water-spraying systems can lower module temperatures but often impose high cost, additional mass, structural complexity, or limited long-term durability, highlighting the need for lightweight, low-cost, and fully passive solutions suitable for large-scale installations. This study develops a thermally conductive epoxy-based composite coating incorporating graphite flakes, GC86PT nanostructured carbon, and a hybrid combination of both materials as a backside passive cooling strategy. The coatings were applied to PV backsheets using a doctor-blade process, and appropriately selected formulations were evaluated through comprehensive thermal, structural, and performance characterization. Outdoor and simulator testing showed that the hybrid coating reduced PV module temperature by approximately 1.37 °C on average and up to 2-3 °C at peak conditions, resulting in an absolute efficiency gain of about 1.30%. The optimized coating remained extremely lightweight (0.089 kg·m-2) and low-cost (2.22 USD·m-2), offering a superior cost-to-performance ratio compared with conventional cooling systems. Overall, the graphite-GC86PT hybrid coating provides a scalable, structurally compatible, and economically viable passive cooling solution for PV modules operating in tropical climates.