New ‘cooling glass’ blasts heat into space

Researchers at the University of Maryland (UMD) aiming to combat rising global temperatures have developed a new ‘cooling glass’ that can turn down the heat indoors without electricity by drawing on the cold depths of space.

The new technology, a microporous glass coating, can lower the temperature of the material beneath it by 3.5°C at noon. According to researchers, led by Liangbing Hu in the Department of Materials Science and Engineering, the coating has the potential to reduce a mid-rise apartment building’s yearly carbon emissions by 10%. The team report this ‘cooling glass’ in a paper in Science.

The coating works in two ways. First, it reflects up to 99% of solar radiation to stop buildings from absorbing heat. More intriguingly, it emits heat into the icy universe, where the temperature is generally around -270°C, or just a few degrees above absolute zero, in the form of longwave infrared radiation.

In a phenomenon known as ‘radiative cooling’, space effectively acts as a heat sink for the buildings. The researchers take advantage of the new cooling glass design along with the so-called atmospheric transparency window –a part of the electromagnetic spectrum that passes through the atmosphere without boosting its temperature – to dump large amounts of heat into the infinite cold sky beyond. (The same phenomenon allows the Earth to cool itself, particularly on clear nights, although with much less intense emissions than those from the new glass developed at UMD.)

“It’s a game-changing technology that simplifies how we keep buildings cool and energy-efficient,” said Xinpeng Zhao, an assistant research scientist and first author of the paper. “This could change the way we live and help us take better care of our home and our planet."

Unlike previous attempts at cooling coatings, the new UMD-developed glass is environmentally stable – able to withstand exposure to water, ultraviolet radiation, dirt and even flames, and enduring temperatures of up to 1000°C. The glass can be applied to a variety of surfaces, including tile, brick and metal, making it highly scalable and adoptable for wide use.

The team used finely ground glass particles as a binder, allowing them to avoid polymers and enhance the long-term outdoor durability of the glass. They chose the particle size to maximize the emission of infrared heat while simultaneously reflecting sunlight.

The development of the cooling glass aligns with global efforts to cut energy consumption and fight climate change, said Hu, pointing to recent reports that this year’s Fourth of July fell on what may have been the hottest day globally in 125,000 years.

"This 'cooling glass' is more than a new material – it's a key part of the solution to climate change,” he said. “By cutting down on air conditioning use, we're taking big steps toward using less energy and reducing our carbon footprint. It shows how new technology can help us build a cooler, greener world."

The team is now focusing on both further testing and practical applications of their cooling glass. They are optimistic about its commercialization prospects and have created a startup company called CeraCool to scale up and commercialize it.

This story is adapted from material from the University of Maryland, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.