Solar Panel Power Output Vs Temperature

This is a well known phenomenon and you will see it listed in the specifications on your solar panel datasheet.

Solar panel power output vs temperature.

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. It may seem counter intuitive but solar panel efficiency is affected negatively by temperature increases. For example if your solar panel lists a power temperature coefficient of 0 30 this means that it produces 0 30 less power for every one celsius degree increase in temperature. Most home solar panels on the market today have power output ratings ranging from 250 to 400 watts with higher power ratings generally considered preferable to lower power ratings.

For example the peimar 270w panels have a pmax temperature coefficient of 0 43 c. In this project you will build a simple circuit and experimental setup to investigate whether the power output of a solar cell changes with ambient temperature. The resulting graph clearly shows that when the panel is at a colder temperature a higher voltage and thus a higher power output is achieved. If a panel with a temperature coefficient of 0 4 c were to reach an extreme heat of 65 c it would reduce output by as much as 26 0 4 x 65.

Although that number sounds small the surface temperature of a dark colored roof in the summer can be significantly higher than 25 c imagine the surface of an asphalt road on a hot summer day. As the temperature of the solar panel increases its output current increases exponentially while the voltage output is reduced linearly. If these solar panels heat up to 45 c 113 f that means they are 20 c above the stc temperature. Solar panel output is expressed in units of watts w and represents the panel s theoretical power production under ideal sunlight and temperature conditions.

It is standard practice to test solar panels for power output at 25 c. A field experiment in the united kingdom revealed a drop of 1 1 of peak output for every increase in degrees celsius of a home photovoltaic solar panel once the panel reached 42 degrees celsius. In many instances a solar cell can get as hot as 65 c causing the panel to become less efficient and therefore produce less power. Abstract solar cells provide a clean way of making electricity directly from sunlight.

So if a panel is rated to have a temperature coefficient of 0 50 per c that panel s output power will decrease by a half of a percent for every degree the temperature rises about 25 c 77 f. Generally cell temperature is 20 30 c higher than ambient air temperature which equates to approximately 8 12 reduction in total power output depending on the type of solar cell and its temperature coefficient. It is called the power temperature coefficient and it will be listed as a percentage of power output loss per degree celsius c.