Hybrid photovoltaic cooling systems: A critical review of cooling configurations, system performance and future prospects

Photovoltaic (PV) modules operate at elevated temperatures under high irradiance, reducing electrical efficiency and affecting long-term reliability. This review critically evaluates hybrid PV cooling systems using a mechanism-based framework that classifies configurations as passive–passive (P–P), passive–active (P–A), and active–active (A–A) according to their cooling mechanisms and auxiliary-energy requirements. The review covers systems integrating phase change materials, fins, metal foams, nanomaterials, hydrogels, heat pipes, liquid and forced-air cooling, thermoelectric cooling, geothermal cooling, mist-assisted cooling, and electric-field-assisted boiling. Among P–P systems, PCM–metal foam reduced PV temperature by about 27 °C relative to uncooled PV, with electrical efficiency reaching 16.18%. P–A systems using nano-PCM/nanofluid PV/T cooling achieved a slightly higher temperature reduction of about 29.3 °C relative to uncooled PV, with an electrical efficiency of 13.7%, indicating that electrical performance is not governed solely by PV temperature. A–A systems using water-spray/forced-air cooling produced a slightly lower temperature reduction of about 24 °C relative to uncooled PV while achieving an electrical efficiency of approximately 15.4%. These findings highlight differences in thermal and electrical performance across hybrid PV cooling systems and show that performance depends on both the cooling mechanism and the integration of complementary cooling components. P–P systems favor simple, low-energy operation, P–A systems provide enhanced heat removal, and A–A systems offer greater cooling control at higher auxiliary-energy demand. Future development should prioritise net-energy performance, climate-responsive design, reliability, cost, and practical long-term operation.