The efficiency of photovoltaic (PV) panels decreases on average about 0.4% for each degree increase. For instance, a PV panel that has an efficiency of 16% at 25°C, will have an efficiency of 15.936% at 26°C, 15.872% at 25°C, and so on.
This is due to the operational voltage of the PV cells decreases significantly with an increase in temperature.
One of the advantages of DualSun PV/T panels is to absorb the wasted heat of the PV cells by the heat exchanger on the backside of the panel and in effect, lower the temperature of the PV cells. This cooling effect allows to increase the PV power output and thus increase PV production by 5% to 15% as compared to a standard PV panel in the same conditions.
We have used a thermal camera to demonstrate the cooling effect on the temperature of the cells:
The circulation of water leads to cooling of the photovoltaic panels. The panel on the left is a DualSun PV/T panel, and the panel on the right is a standard PV panel. We observe that the uniform circulation of the water through the DualSun heat exchanger allows for a cooling of the whole surface of PV cells and that the temperature difference between the two panels is approximately 20°C. This means that in this case, the DualSun panels will have a photovoltaic efficiency approximately 9% better than the standard PV panel (16%-14.65%)/14.65%.