New material for energy saving
Imagine that the sun is full in our window and this increases the temperature of the house to uncomfortable limits. But there is a material ten times thinner than a hair that manages to reduce the temperature of the window a few degrees and, consequently, of the interior. And that, in addition to comfort, means great savings on air conditioning. This is what researchers from the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and the Institute of Materials Science of Madrid (ICMM-CSIC) have achieved, with the creation of this new material. His work has been published in the magazine Small.
The new material is capable of removing heat and thus cooling the surface where it is placed without energy consumption or gas emissions of any kind. It is formed by a matrix of 8 micron diameter silica spheres - 8 millionths of a meter, ten times thinner than a human hair. Compared to grains of sand, they have a volume a million times smaller.
The material is inspired by the Earth's temperature regulation mechanism, called radiative cooling. Our planet receives ultraviolet radiation from the Sun and this increases the surface temperature. But a part of this energy returns to space as infrared radiation. Thus the temperature is regulated. And precisely the greenhouse effect, caused by gases such as carbon dioxide, causes much of this infrared radiation to be retained and the Earth's temperature increases. In any case, what has interested the researchers is that the main responsible for the expulsion of the radiation are the grains of sand from the deserts.
One of the main applications would be to cool the solar panels, so that excessive heat decreases their performance. Researchers have shown that with the new material a silicon wafer can be cooled to 14 ° C under direct sunlight. A common glass only lowers the temperature 5 ° C. On a surface such as that of a solar panel, it has a radiative cooling power of up to 350 W / m2.
