Researchers at the University of Colorado Boulder have created a new material which is capable of cooling a structure without consuming energy or water. This material is able to cool the structure even if it placed directly under sunlight. Their study is published in the journal Science.
Xiaobo Yin, the leader of the study, and his colleagues described their material as eco-friendly. They explained it could work as a cooling method for thermoelectric power plants that usually need quite high quantities of water and electricity to reach the temperatures necessary for them to work.
The magnificent material can be applied on the surface as a film which reflects the solar energy and lets the surface release both its heat and infrared thermal radiation. It is made of a combination of glass and polymer and is only a little bit thicker than aluminum foil (50 micrometers).
It can be also used on large scales, since it is so thin and it can be organized into rolls. Such a manufacturing process is both cheap and economic and is applicable for both residential and commercial use.
This material works as a passive radiative cooling mechanism. This means that it sheds natural heat (in this case, infrared radiation) without the need of energy. Nighttime cooling can work perfectly by using thermal radiation. However, daytime cooling is a bit more challenging, since any bit of solar energy that is absorbed can make the passive radiation process ineffective.
To solve this problem with daylight, scientists had to make possible for the material to reflect sunlight and, at the same time, allow infrared radiation to escape. Thus, they added glass microspheres in the material that can both scatter and radiate the infrared light into polymer film. Also, they added a thin silver coating underneath to enhance the reflecting properties of the material.
Besides cooling rooftops, this material can be used with solar panels. It can extend their life span and make them more efficient. Although they convert sunlight into energy, they can also heat up and become less effective.
The researchers are also going to analyze their applicability in agriculture or aerospace. They have already submitted a patent application and are currently exploring what commercial use they might make of the cooling material.
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