Using advanced computing methods and artificial intelligence, researchers have designed a clear window coating that lowers the temperature inside buildings. The coating can reduce the energy used to cool indoor spaces by 31 percent compared with normal glass windows in hot climates.
The material, reported in the journal ACS Energy Letters, lets visible light through, but blocks the sun’s warming infrared and ultraviolet rays. It also radiates heat from the window at a wavelength that passes through the atmosphere into outer space.
Cooling homes and buildings consumes 15 percent of the energy that the world produces. And the planet’s warming climate is pushing people to use yet more energy-intensive air-conditioning.
To reduce this burden, researchers have been on the hunt for low-energy alternatives to cooling indoor spaces. Windows are a big part of a building’s cooling energy waste because they let in warmth from the sun. So one promising route to passive cooling is to coat windows with materials that block infrared light, but such films can also block visible light so they appear dark or frosted. Another option for electricity-free cooling are materials that radiate heat into space.
Researchers from Kyung Hee University in South Korea and the University of Notre Dame wanted to make a smart window coating that combines the best of these features. They turned to computer modeling and successfully designed a material that is both transparent, and radiates heat into space.
The film can be manufactured using state-of-the-art material deposition techniques, so they could be made on large scale for practical applications, say the team.