FROM THERMAL ACCUMULATION TO HYBRID REGULATION: A COMPREHENSIVE REVIEW OF COOLING STRATEGIES IN PHOTOVOLTAIC AND PV/T SYSTEMS

Abstract

 Both Photovoltaic (PV) and Photovoltaic/Thermal (PV/T) systems still remain significantly affected by thermal energy storage since around 70–80% of the sunlight absorbed turns into heat and not electricity. This leads to overheating and reduction of the systems' efficiency under hot weather conditions. The current research paper seeks to provide a critical review of some of the latest findings concerning thermal management solutions for PV and PV/T technologies while building a framework that connects cooling approaches to thermo-electrical performance. For the purpose of the research, a systematic analysis and comparison of more than 60 scientific papers, especially those written within the years 2022-2025, are considered alongside basic studies on the cooling of PV/T systems. Passive cooling includes methods such as using Phase Change Materials (PCMs). Active cooling technologies include air, water, and nanofluid cooling. Finally, hybrid solutions that involve PCMs and enhanced convective heat transfer are also studied. Comparative analysis shows that passive cooling with PCMs is relatively simple and highly efficient in terms of thermal energy storage while active cooling with nanofluids allows reaching up to 20 degrees centigrade decrease in temperatures and up to 15% efficiency improvement. In turn, hybrid solutions allow obtaining even better thermo-electrical efficiency at high levels of irradiation, up to 80%, due to up to 25°C temperature drop achieved in experiments. Yet, several challenges need to be addressed: pumping losses, nanofluids stability issues, PCMs performance in cycles, etc.