This incredible device both harvests solar energy and sends excess heat into space

We are faced with a deadly catch 22. As the world gets hotter, people put the air conditioning on. As they crank up the air conditioning, the world gets hotter. And so on. And so on.

If it seems like there is no escaping this gloomy, no-win situation, take your heart: a new technology developed by scientists from the US and China could literally shine a light in the dark – and not just in the dark, but also in the cold emptiness of seemingly endless space.

Researchers at Stanford University have invented a new type of solar panel technology that not only harvests light from the sun and converts it into electricity (like conventional panels do), but also allows surplus heat to radiate into space at the same time.

"We built the first device that one day could save energy and save energy, in the same place and at the same time, by controlling two very different properties of light," explains electricity engineer and lead author of the new research, Shanhui. Fan.

The principle that Fan talks about is called radiation cooling, where an object – every object, including buildings, or even your own body – emits heat in the form of infrared light.

When objects do this, they at the same time lose heat through the process of heat radiation, but while the phenomenon seems a great way to displace the threatening heat problems of the earth, there is a pitfall: not all the heat emitted escapes our atmosphere and makes it in the space .

"Think of the atmosphere as a big blanket over the earth," one of the researchers, Zhen Chen, formerly from Stanford and now a professor at the Southeast University of China, Fast business.

"This blanket does not allow heat to go easily from the earth to the cold universe, but there are" holes "in the blanket, if you want to think about it that way, bringing the heat to space. can shine. & # 39;

The new prototype that the researchers have developed is a first-of-its-kind attempt to combine a radiation cooling system with a conventional solar panel, creating a kind of hybrid technology that absorbs sunlight and diffuses infrared light into the air.

The unit is composed of a conventional solar absorption device with the size of a compact disc (if you remember it), which sits above a similar circular radiation cooler, made of silicon nitride, silicon and aluminum layers enclosed in a vacuum.

The idea is that the solar panel is transparent to infrared, so although it would absorb most of the sunlight from the sun, infrared light (with a wavelength between 8 and 13 micrometers) passes through and can be emitted into space – for as far as it can navigate atmospheric & gaps & # 39; at least.

During testing, the device – which builds on the earlier innovations for radiation cooling of the team in 2014 and 2015 – has succeeded as a proof of concept, with the lower layer (the radiation cooler) recording lower temperatures than both the ambient air temperature and the solar panel.

836 radiation cooling solar panel 2
(Chen et al / Joule)

"This shows that heat is radiated from below, through the top layer and into the room," Chen explains, although there is still a lot of work to be done before this type of double-acting solar panel can be installed on roofs. the world.

To begin with, the solar panel in the team's prototype was not really functional in terms of electricity production, which is the next problem for the researchers to solve: developing working solar cells with elements that do not block infrared light from braving where no one has been there before.

Once that technical obstacle has been overcome, the air is no longer the limit.

"It is generally recognized that the sun is a perfect source of heat that nature offers to man on earth", Chen says.

"It is less generally recognized that nature also offers man the space as a perfect heat sink."

The findings are reported in Joule.