| Work Detail |
Researchers at the University of New South Wales have created vortex generators that can reportedly reduce the operating temperature of solar modules by up to 2.5°C. They built two different prototypes, based on aluminum and a 3D-printable conductive polymer, and tested them in various scenarios in an experimental environment deployed in Sydney.
Scientists at the University of New South Wales (UNSW) in Australia have used rectangular vortex generators (VGs) as a passive cooling technique for photovoltaic panels and have found that they can reduce the operating temperature of the modules by 1.5 ºC and 2.5 ºC.
VGs are commonly used to delay flow separation and are typically placed on the external surfaces of vehicles and wind turbine blades. These devices have also been applied for cooling photovoltaic-thermal (FVT) modules in research, but were not yet used only for PV modules, due to the “totally unpredictable” flow conditions, according to the research team. .
“Our previous indoor experiments have shown that the rectangular-wing VG can achieve up to 3°C of cooling under free convection conditions,” the scientists explained, referring to a previous attempt they made to use VGs for cooling PV panels. “By introducing longitudinal vortices near the rear surface of the module, a VG array enhances convective heat flow and consequently reduces the operating temperature of the module. In this study, the same VG design was applied to the configuration of an open-air open-frame PV system.”
The scientists used VG with a size of 2 cm x 3 cm and shaped like a rectangular wing bent at an angle of 30 degrees. They built 400 pieces based on aluminum and 400 pieces based on a 3D-printable conductive polymer. They then attached them to the back of two different 285W polycrystalline panels supplied by Taiwanese manufacturer Winaico. The academics also used thermal conductive tape to create thermal contact between the VG and the module.
“Except for the bottom and the top row of silicon cells, where the junction box is located, the VGs covered most of the surface of the 1 m × 1.65 m module,” they explained. “The vertical pitch is 8 cm, which allows two rows of VG to be installed in an M2 format cell and 16 rows of VG in each module. In this way, the VGs cover 12.5% ??of the rear surface of the module, which considerably reduces the use of material compared to other heatsinks.”
The proposed technology was tested in an experimental environment deployed on the rooftop of a Sydney building, with the panels tilted at 30 degrees. Temperature sensors were placed on the back surface of the panels and meteorological and radiation data were collected through a weather station, while a thermal camera was used to visualize the temperature distribution on the back surface of the modules.
The tests showed that the VGs based on the 3D printable polymer were capable of reducing the temperature of the modules by up to 1.5 ºC under conditions of high irradiation and low wind, or with a southerly wind. For their part, the aluminum VGs reduced the temperature of the modules by about 2 ºC in conditions of high irradiance or 2.5 ºC in conditions of high temperature and high wind speed.
“Both VGs exhibit equivalent performance with southerly and westerly winds, indicating the dominance of the vortex generation mechanism,” the group stated. “The module equipped with VGs exhibited an increase in the convective heat transfer coefficient evaluated by the thermal balance model.” |
