New type of solar cell can provide electricity even at night

Any object that has heat — like a tree, building, or human body — needs a way to dissipate heat. One method to do that is through radiative cooling, a process by which a body or object loses heat by emitting waves of electromagnetic radiation that are invisible to the human eye. This phenomenon usually occurs at night and cools the planet as the gathered heat waves disappear into the atmosphere and beyond.

As it turns out, radiant cooling could also be our ticket to renewable energy at night for countless people around the globe.

In a new study published Tuesday in the journal Alphabetical Applied Physics, researchers at Stanford University have created a photovoltaic (PV) cell, which collects and converts solar energy into electricity, generating large amounts of electricity by absorbing the energy emitted by radiation cooling. This new type of PV battery can significantly extend the life of solar panels and serve as a reliable source of energy for the more than 750 million people living without electricity worldwide.

Shanhui Fan, an electrical engineer at Stanford University who led the study, told The Daily Beast, capturing thermal radiation is similar to how a hydroelectric dam captures energy from falling water and converts it into electricity. usable.

In the case of their modified PV cell, Fan and his team tapped into an invisible reservoir – the surrounding air through which thermal radiation travels – and attached an insulating material called tissue. – electric heating. The material acts like a hydroelectric dam, taking heat and producing energy from it.

The amount of electricity generated is quite modest – around 50 milliwatts per square meter – and not competitive enough to compare with the hundreds of watts per square meter produced by a typical solar panel. Still, it’s still a remarkable feat for a prototype, Peter Bermel, an electrical engineer at Purdue University who was not involved in the study, told The Daily Beast in an email.

Sid Assawaworrarit

But electrical modesty is what Fan and his team are all about.

“What [this PV cell] what can be helpful is giving you a convenient light source, things like lighting up LEDs and charging cell phones or sensors, that kind of thing,” he said.

Another added bonus is that the energy gained from radiation cooling can boost PV cell efficiency during the day, Fan and his team have found.

“During the day, when you use the solar panel, [the thermoelectric module] Fan said.

The researchers also encountered a number of obstacles in making their new PV cells more energy efficient and cost-effective. But Fan hopes that one day his team’s equipment can provide a source of electricity for people in developing countries that are hard to find reliable power anywhere else, especially in At night.