Vortex Generators for Passive Cooling of Rooftop Photovoltaic Systems under Free Convection

Decreasing the operating temperature of a photovoltaic (PV) module can increase its electrical output and longevity. This can be achieved by increasing the radiative and convective heat losses on the front or the rear module surface. In this article, we have proposed and investigated, experimentally and numerically, a passive cooling method for the rooftop PV system, which enhances convection heat flux on the module's rear surface. As the vortex generators (VGs) are attached on the surface of the roof without physical contact to the module backsheet, this technique would not void the module warranty and can be easily retrofitted on an existing rooftop system. In the absence of wind (free convection), the module is subjected to the highest temperatures, and our VG design specifically targets this worst-case scenario. Our results reveal a temperature reduction of more than 4 °C using VGs in the configuration studied. This can be translated to a significant increase in module lifespan by around 30% to 40%, thus reducing the levelized cost of electricity.