Dual PV module cooling tech based on water, air

Scientists in Hungary have built an experimental rig that uses a 60 W polycrystalline solar panel with 152 holes drilled into its frame for air cooling, as well as high-conductivity copper alloy pipes and fins placed on its back for water cooling.

Researchers from the Hungarian University of Agriculture and Life Science and the University of Kufa in Iraq have developed a novel dual-PV module cooling technique based on water and air.

For air cooling, it utilizes a perforated frame and a fan; whereas for water cooling, it employs pyramid-shaped fins and a serpentine pipe. The team constructed and tested an experimental rig of the system.

“The proposed design features an innovative solar panel frame with strategically positioned perforations, presenting a special approach to cooling technologies by enhancing airflow dynamics,” they said. “By effectively managing and reusing this thermal energy, the design significantly improves the solar energy system’s thermal regulation and overall efficiency.”

The experimental rig was based on a 60 W polycrystalline solar panel. For the air cooling part, the academics have drilled 152 holes on the sides of the frame, through which air is introduced. A hole was also drilled on the back of the panel, serving as the air outlet. A fan was attached to the outlet, with airflow regulated at 1.1 m/s. As for the water cooling part, a serpentine pipe was mounted to the back of the solar panel, with 11 fins in between.

The research team built both the pipe and the fins with a high-conductivity copper alloy, which purportedly optimizes heat transfer efficiency. It also mounted the pipe and fins onto the surface via a special high thermal conductivity adhesive to ensure direct contact and enhance the transfer of energy. A wooden sheet was then fixed to the panel frame to create an air channel and two insulation sheets were added.

The outlet hot air from the system was assumed to support the space heating of a house, while the outlet hot water was stored in a water tank. In addition to this novel system (PV-d), two other systems were constructed for compression purposes: the first was a system including the 60 W module with no cooling (PV-r), while the second included the panel and air cooling only (PV-a).

All the rigs were placed in the city of Gödöllő, in central Hungary. They were installed on a tilted aluminum frame with a tilt angle of 43◦ oriented southward, with an azimuth angle of (-19◦). Performances were recorded over two consecutive days, characterized by clear sky conditions in May 2024.

“The PV-d system exhibited improved electrical efficiency, producing up to 42.87 W at 1,018.76 W/m2 irradiance compared to 30 W for PV-r, marking a 42.4% increase,” the results showed. “The PV-d system achieved a significant improvement in thermal efficiency, outperforming the air-cooled system by approximately 48.5% at an irradiance intensity of 1,018.758 W/m2.”

Moreover, the scientists found that the PV-d maintained average temperature reductions of approximately 5.4 C and 12.5 C relative to PV-a and PV-r, respectively. It also demonstrated an average exergy efficiency of 27.7%, compared to an average efficiency of 16.2% observed for the air-cooled PV-a system and 6% for the reference PV-r system.

The system was presented in “Optimization of dual-cooling technique in perforated solar pv modules: experimental insights towards carbon neutrality and sustainability,” published in Energy Conversion and Management: X.