Researchers Turn to Polyethylene Aerogel for Passive, Zero-Power Sub-Ambient Cooling

Researchers from the Pontificia Universidad Católica de Chile (Pontifical Catholic University of Chile) and the Massachusetts Institute of Technology (MIT) have published paper detailing a cooling system which requires no power or moving parts to drop temperatures by up to 13°C (23°F) in direct sunlight.

The researchers' creation uses a lightweight aerogel made from polyethylene, which blocks the sunlight that falls on an object while allowing the infrared radiation from the object to pass outwards — meaning the object is still free to radiate heat to cool itself, something traditional insulation materials would prevent.

The work builds on an earlier project led by Professor Evelyn Wang, which used a strip of metal as a barrier to block incoming sunlight. The new version, though, is considerably more effective with around twice the cooling power of its predecessor.

To prove its capabilities, the team tested the material in Chile’s Atacama desert - achieving 13°C (23°F) of cooling in the full noonday sun. In the slightly less scorching MIT campus in Massachusetts, the same material fell just short of offering 10°C of cooling — still an impressive figure, though the team is working towards a goal of 50°C.

The aerogel can be used, the team explain, to help preserve produce, cool water, or as an initial cooling stage for electric refrigeration and air conditioning systems to reduce the amount of electricity they consume. They also claim it can be used as an add-on to any other type of cooling system, as a means to boost its performance at a very low cost.

The team's work has been published in the journal Science Advances, while a more detailed write-up is available on MIT's website.