An innovative method to control surface temperature of a rooftop photovoltaic system

•The proposed method controls the panel’s temperature during the summer.•This method facilities snow removal process from a PV panel.•Using venting channel causes approximately 50% less energy loss.•Maximum energy loss due to the insulations is less than 5%. Photovoltaic solar systems in cold regions deal with energy loss due to snow accumulation on the system during the winter and panel temperature increase during the summer. In this paper, a method is proposed to control the surface temperature of a rooftop PV panel during all seasons via having a particular insulation mounted on the back of the PV panel. The main reason for such insulation is the need for snow removal from the panel during the winter. Using a heating snow removal system with the insulation can improve the panel performance significantly; however, during the summer, it can increase the panel temperature, reducing the energy production of the panel. Therefore, a modified insulation system has been proposed to reduce the adverse effect of having insulation during the summer. The insulation on the back of the panel produced an air channel of approximately 3 cm depth equipped with several vents. The insulation was also painted black on the side facing the panel to increase radiative heat transfer from the panel. In the summer, natural convection through the vents and radiation heat transfer between the panel and the insulation help to control the panel temperature. On the other hand, during the winter, closing the vents maximizes the effect of a snow removal system. Several experiments were conducted under natural conditions for a rooftop system equipped with the new insulation. The effect of solar radiation and vent configurations on the panel output were studied to find the optimum configuration for the vents. A numerical simulation was also conducted to investigate the effect of other parameters: wind speed, panel tilt angle and surface emissivity of the insulation. The proposed venting system can provide approximately 50% less energy loss as compared to the case that the insulation did not have any open vent, while still minimizing the energy required for snow removal in the winter period.