Air conditioning is among the more important inventions because it allowed people to settle in places that would otherwise be too warm. In those and other areas though, air conditioning can be one of the larger power usages, which is why researchers are working on better cooling systems. Those at the Stanford School of Engineering have recently developed a passive cooling structure that can keep a building cool in direct sunlight.
Passive cooling systems that reflect sunlight off of a building have been created before, but run into two problems; the reflectors will absorb some sunlight and warm, and the atmosphere may reflect some light back onto the building. The researchers solved both of these problems though by applying advanced photonics to their reflectors. The photonics used in the reflectors are designed to absorb less light and to emit specific wavelengths which are able to travel through the atmosphere, instead of being reflected by it. The result is a net cooling power of 100 watts per square meter from a passive cooler.
While the design is something that could be used on large buildings, the researchers also see it being used in areas with little electricity. Potentially the reflectors could be used to cheaply cool homes and other buildings there.
Source: Stanford School of Engineering