Experimental study on a dual-channel air-cooled photovoltaic/thermal system with glass cover plates

Although photovoltaic/thermal (PV/T) systems offer a highly promising solution for simultaneous electricity generation and heat supply, traditional air-cooled designs often face a trade-off between PV (photovoltaic) cooling and efficient heat collection, particularly when heat flux distribution is uneven. To address this limitation, this study proposes a novel dual-channel air-cooled PV/T system featuring two independent airflow channels, each with distinct functional zones. Unlike conventional single-channel configurations, which treat the entire rear surface of the PV module as a single unit, the proposed design aims to optimize thermal management by separating the heat extraction process. Outdoor experiments under multiple operating conditions were conducted on a custom platform in Zhengzhou, China, to evaluate key performance metrics—including photothermal efficiency and temperature distribution—under varying solar irradiance and airflow velocity conditions. This study systematically compares the proposed dual-channel system with a conventional single-channel reference system. Research findings indicate that, for single-channel systems, higher airflow results in better photothermal efficiency. In comparative operating conditions, the optimal photothermal efficiency was achieved at an air velocity of 3.5 m/s. For dual-channel system, the upper air duct, due to its direct contact with the back of the PV panels, can remove waste heat more efficiently, its outlet temperature is typically 4–5 °C higher than that of the lower air duct. At the same operating conditions, the thermal efficiency of the single-channel configuration is 2.1 times that of the dual-channel system. Under high solar radiation intensity, rising ambient temperatures further enhanced thermal efficiency. The highest thermal efficiency of 28.3% was recorded at around 1:00 p.m. These findings contribute to the optimization of air-cooled PV-thermal systems and provide theoretical and practical guidance for future design and application.