Solar panels work most efficiently at a temperature of 25 ℃ and then decrease with the increase of temperature. Therefore, researchers at the University of Kansas think about how to extract heat from solar panels when the temperature is too high.

After comparing three roof materials, they find that the solar panels installed on the “green roof” have the best effect, Compared with white or black roofs, the conversion energy is increased by an average of 1.4%.

Most solar panels are installed on the roof of residential buildings and must undergo the test of wind, sun and rain. Although they take the sun, they are also suffering from the sun. When the temperature of solar panels rises above 25 ℃, the performance will gradually decline.

In order to solve this problem, two doctoral students from the school of architecture and design of the University of Kansas have now found the best home for solar panels from experimental research.

They compared the three types of roof materials most commonly laid by solar panels: highly reflective white roofs, the most traditional and common black roofs, and green roofs planted with vegetation.

The green roof consists of a series of layers, usually from top to bottom: vegetation, covering layer, matrix layer (growth medium), filter membrane, drainage layer and waterproof membrane laid on the roof structure of the building.

Mohammed alshayeb, one of the doctoral students, installed a solar panel monitoring system, temperature / humidity / light sensors, and even a weather station for recording wind speed on three roofs. These sensors recorded data every five minutes for a period of one year, and then alshayeb analyzed it.

The concept of solar energy industry often believes that white roofs are the most friendly to solar panels because they can reflect sunlight. But the researchers found that compared with black roofs, white roofs actually reflect heat to solar panels, resulting in a slight reduction in the efficiency of solar panels.

Compared with the green roof, the small gap between the black and white roof can be almost ignored, because the solar panels installed on the green roof have the best performance and increase the conversion energy by an average of 1.4%.

There are a lot of research in this area, but associate professor Jae Chang of the school of architecture and design at the University of Kansas said that this research is more comprehensive. The next step is to test the effect of increasing the height of solar panels on the roof.