Cooling metamaterial scaled up for low power air con

The glass-polymer hybrid metamaterial, which first appeared in the journal Science in 2017, was developed by engineers at the University of Colorado Boulder (CU Boulder). Working with colleagues from the University of Wyoming, the technology has now been built out into a functioning cooling system for buildings. The technology, which takes advantage of radiative cooling principles, is described in the journal Joule.

“As Earth’s temperature warms due to the absorbed heat from the sunlight during the day, it continuously emits infrared light to the cold universe all the time,” said lead author Professor Ronggui Yang of CU Boulder’s Mechanical Engineering school. “During the night, Earth cools down due to the emission without the sunshine.”

Similar to this natural process, the team’ film-like material reflects almost all incoming sunlight while still allowing an object’s stored heat to escape, keeping it cooler than ambient air even in the midday sun. At noon under stationary conditions, the proprietary RadiCold module kept a container of water covered by the metamaterial 10.6°C below the ambient temperature.