New engineered material can cool roofs and structures with zero energy consumption

Researchers at the University of Colorado Boulder have developed a new material that can bring down building temperatures without consuming electricity or water in the process.

Measuring just 50mm thick—about the thickness of kitchen aluminium foil—the glass-polymer hybrid film cools the body underneath, even under direct sunlight, by reflecting solar energy back into space while allowing the surface to lose heat via infrared thermal radiation.

Image: University of Colorado Boulder

It can be mass produced in rolls, pointing to a huge potential for application in large-scale residential and commercial projects.

“This low-cost manufacturing process will be transformative for real-world applications of this radiative cooling technology,” said Yin Xiaobo, co-director of the research and an assistant professor at CU Boulder’s Department of Mechanical Engineering and the Materials Science and Engineering Program.

According to the study, which was published in the journal Science, the material can also improve efficiency and longevity of solar panels. Under direct sunlight, panels tend to overheat, which hampers the ability to convert solar energy into electricity.

“By applying this material to the surface of the panel, it can cool the panel and recover an additional one to two percent of solar efficiency,” said Prof Yin in an interview.

“Just 10 to 20 square metres of this material on the rooftop could cool down a single-family house in summer,” said Gang Tan, an associate professor at the University of Wyoming’s Department of Civil and Architectural Engineering and one of the study’s co-authors. 

The discovery is the product of a US$3 million grant awarded in 2015 by the Energy Department’s Advanced Research Projects Agency-Energy (ARPA-E). The team has applied for a patent and is exploring potential commercial applications.