Efficiency Of Solar Panels Vs Temperature

The effect of high temperatures.

Efficiency of solar panels vs temperature.

Most solar panels have a temperature coefficient of around 0 3 c to 0 5 c. For example the peimar 270w panels have a pmax temperature coefficient of 0 43 c. If the surface temperature of your roof increases to 30 c 86 f your solar panel s efficiency will fall to 16 7 percent. A field experiment in the united kingdom revealed a drop of 1 1 of.

The energy production efficiency of solar panels drops when the panel reaches hot temperatures. As the temperature of the solar panel increases its output current increases exponentially while the voltage output is reduced linearly. For example when the temperature coefficient is minus 0 5 percent it means that efficiency decreases by 0 5 percent for every degree above 25 c or every 33 8 degrees above 77 f. If these solar panels heat up to 45 c 113 f that means they are 20 c above the stc temperature.

Solar panels are tested for their efficiency at 25 c and that is why this is used as the reference point. Photovoltaic modules are tested at a temperature of 25 degrees c stc about 77 degrees f and depending on their installed location heat can reduce output efficiency by 10 25. For example sunpower s solar panels all have a temperature coefficient of 0 37 c. Lost energy 20 x 0 43 8 6 100 8 6 x 270w 91 4 x 270w 246 78w.

The above equation shows that the temperature sensitivity of a solar cell depends on the open circuit voltage of the solar cell with higher voltage solar cells being less affected by temperature. If you have solar panels with an efficiency rating of 17 percent and a temperature coefficient of 0 45 they will lose 0 45 of their efficiency for every degree above 25 c.