An international research group has designed a new photovoltaic thermal module assembly, where zirconium oxide is used as a cooling agent. The system is said to lower its operating temperature more efficiently than water-cooled counterparts.
The goal of their work was to compare the performance of the system with that of uncooled PV systems or water-cooled systems in hot climates.
“The experiments were conducted in May 2022 on sunny days from 7:00 a.m. to 5:00 p.m. without significant variation in ambient temperature and solar radiation during the experiment days,” the researchers said. “The highest ambient temperature was 42.7 C, particularly at 12:20 p.m., after which it gradually decreased until sunset.”
The experimental environment was located in the city of Basra in southern Iraq. It consisted of a PVT module that was cooled ZrO2A PV module cooled by water and a PV module without cooling, all of which have a nominal power of 50 W. The PVT module uses an absorbent copper plate with flow channels attached to the back side, which lowers the temperature of the module.
The team also applied a layer of thermal wool over the serpentine tubes to completely cover the back of the PV module and reduce heat loss, then covered it with an aluminum sheet. The ZrO2 nanofluid is circulated in serpentine pipes with two pumps with a mass flow rate of 0.7 l/min with flow sensors.
The researchers used three different concentrations of ZrO2 0.015%, 0.025% and 0.0275% in the PVT system, which they said resulted in a temperature drop of 14%, 18.1% and 21.2% compared to a comparable PVT panel without cooling. The operating temperature of the water-cooled module decreased by 9.7%.
They presented the system in a study “Effect of zirconium oxide nanofluid on the behavior of a photovoltaic-thermal system: an experimental study, published in Energy reports. “Current research can be extended by improving the thermal properties of ZrO nanofluid by adding another type of nanomaterials to form a hybrid nanofluid, which was applied to a new cooling system design, they noted.