Transparent window coating could cool buildings without energy

The technology could help save a ton of energy for cooling, which is estimated to account for about 15% of global energy consumption

With climate change making summers unbearable, the demand is growing for technologies to cool buildings. To help tackle this problem, researchers have designed a transparent window coating that could lower the temperature inside buildings — without using a single watt of energy.

This is fairly important, with studies estimating that cooling accounts for about 15% of global energy consumption. That demand could be lowered with this window coating, which could block the sun’s ultraviolet and near-infrared light — the parts of the solar spectrum that typically pass through the glass to heat an enclosed room. Moreover, energy use could be reduced further if the coating radiates heat from the window’s surface at a wavelength that passes through the atmosphere into outer space.

However, the challenge is to design materials that can meet these criteria simultaneously and can also transmit visible light — meaning they don’t interfere with the view.

The team used advanced (quantum) computing technology and AI to construct computer models of “transparent radiative cooler” (TRC) consisting of alternating thin layers of common materials like silicon dioxide, silicon nitride, aluminum oxide, or titanium dioxide on a glass base — topped with a film of polydimethylsiloxane. They optimized the type, order, and combination of layers using an iterative approach, producing a coating design that — when fabricated — beat the performance of conventionally designed TRCs in addition to one of the best commercial heat-reduction glasses on the market.

TRC graph

According to researchers, the optimized TRC could potentially reduce cooling energy consumption by 31% in hot, dry cities. They note their findings could be applied to other applications since TRCs could also be used on car and truck windows. Additionally, the group’s quantum computing-enabled optimization technique could be used to design other types of composite materials.

The research was conducted with support from the National Research Foundation of Korea and the Notre Dame Center for Research Computing. The research team includes Eungkyu Lee from Kyung Hee University in South Korea and Tengfei Luo, Seongmin Kim, Wenjie Shang, and others from the University of Notre Dame in the U.S.

Takeaway

Due to climate change, the average global temperature will rise in the coming decades. This should also significantly increase the demand for the building's cooling energy to keep the indoor temperature at a comfortable level.

The international team of researchers has used advanced computing technology and AI to design a transparent window coating that could lower the temperature inside buildings without expending a single watt of energy. This can help reduce power bills and carbon emissions.

The new window coating, called the "transparent radiative cooler" (TRC), radiates heat from the window's surface at a wavelength that passes through the atmosphere into outer space. Also, it is clear enough to let visible light in and not interfere with the view, and can potentially reduce cooling energy consumption by 31% compared with conventional windows.
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Action point

FOR PUBLIC OFFICIALS:
While the TRC is still not available, as a public official - you can inquire about its availability to be the first in line to get it once it hits the market. Or, you can try to find similar solutions that could cut cooling costs for government-owned buildings, reducing CO2 emissions along the way. Using coating, no matter how fancy, is still a more affordable solution than building a new building from the ground up.

FOR BUSINESSES:
The TRC may not be on the market just yet, but if you're in the business that could sell these solutions, you may content researchers to explore the option of helping them sell this tech once it's ready for prime time. Or, you can explore other similar solutions that could cool down buildings on a budget. After all, a coating is probably among the more affordable solutions to get this work done.