Scientists from the United States are going to maintain a comfortable temperature in buildings, using the effect of passive radiation cooling. Especially for this they have developed a porous polymer, which, reflecting sunlight, cools the surface on which it is applied.
After the researchers decided to develop passive cooling technology, they realized that today’s solutions cannot be applied on a large scale. It turned out that all materials that are reflective and emitting properties suitable for their purposes are either very expensive or difficult to manufacture. That is why the most popular solution from the point of view of passive cooling so far has been the usual white paint. But its properties are far from ideal.
In developing an alternative, one of the American research groups received a polymeric material, the structure of which contains many nanoscale voids. This feature, according to scientists, allows the new polymer to cool any object on which it is applied.
The voids in the polymer reflect and radiate heat waves. This is due to the difference in the refractive indices of thermal radiation in the voids and dense polymer layers that surround them. The team of researchers turned out to be a material, the reflection coefficient of which is 96%, and the emissivity factor is 97%.
Tests have shown that in the Arizona desert an object covered with such a polymer, without any additional devices, has a temperature 6 ° C below the environment.
The developers say that you can cover anything with this material: roofs of houses, walls of buildings, water tanks, vehicles and even space ships.