New Solar Panel Technology Harvests Light from the Sun and Also Converts it into Electricity

The world is caught in a vicious circle. As it grows hotter, people turn up their air conditioning but as they turn up the air con, the world grows hotter. And so it repeats and repeats.

But now there might be hope: a new technology produced by scientists from the US and China could literally shed light in the dark – and not just any dark either, but the vast emptiness of space.

Researchers from Stanford University have invented a new kind of solar panel technology that harvests light from the Sun but also converts it into electricity (like conventional panels do). However, this new tech can also beam excess heat into space simultaneously.

Shanhui Fan, an electrical engineer and the senior author of the new research explained that they built the first device that could one day make energy and save energy, in the same place and at the same time, by controlling two very different properties of light.

The principle Fan mentions is known as radiative cooling, where an object – any object, including buildings, or even your own body – emits heat in the form of infrared light.

When objects do this, they simultaneously lose heat by the process of thermal radiation, however, while the phenomenon might appear to be a great way of displacing Earth’s impending heat problems, there’s a hitch: not all the emitted heat escapes our atmosphere and makes it into space.

Zhen Chen another researcher on the project, formerly of Stanford and now a professor at the Southeast University of China, told Fast Company to think about the atmosphere as a big blanket around our planet. This blanket does not permit heat to easily go from the Earth into the cold universe. However, there are ‘holes’ in the blanket, if you want to think about it that way, through which the heat can radiate out to space.

The researchers developed this new prototype, a first-of-its-kind attempt for combining a radiative cooling device with a conventional solar panel. The result is a type of hybrid technology that absorbs sunlight while also emitting infrared light into the sky.

The unit is composed of a conventional solar absorber array around the size of a compact disc, which sits above a similar circle-shaped radiative cooler, comprised of silicon nitride, silicon, and aluminum layers enclosed in a vacuum.

The concept is that the solar panel is transparent for infrared, so while it should absorb most of the Sun’s light, infrared light (with a wavelength between 8 and 13 micrometres) passes through it and can be emitted into space – as long as it can navigate atmospheric ‘holes’ at least.

The device – which builds on the team’s earlier radiative cooling innovations in 2014 and 2015 – succeeded as a proof of concept during testing, with the bottom layer (the radiative cooler) recording lower temperatures than both the ambient air temperature and the solar panel.

In a statement, Chen explained that this shows that heat radiated up from the bottom, through the top layer and into space. However, a lot more work needs to be done before this kind of double-duty solar panel could be installed on rooftops globally.

First, the solar panel in the team’s prototype wasn’t actually functional concerning the production of electricity, which is the next issue the researchers need to work on. They must develop working solar cells with elements that don’t block infrared light from being able to go where no one has gone before.

Once that technical obstacle is overcome, the sky is no longer the limit.

Chen. stated that everyone realizes that the Sun is a perfect heat source offered by nature for human beings on Earth, however, it is less widely recognized that nature also provides human beings with outer space as a perfect heat sink.

Their results are reported in Joule.


Image Credit: Diyana Dimitrova / Shutterstock


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