Solar panels work by converting the sun’s radiation into energy. But at night the opposite happens more or less, Say Syed Aswarat, a researcher at Stanford University in California. And because the solar panels, he says, are an “effective heat radiator,” they themselves emit infrared radiation at night. Assawaworrarit and colleagues use this radiation to generate energy.
By equipping an ordinary solar panel with a thermoelectric generator, a device that can extract energy from temperature differences, a small amount of electricity can be generated. Thus the solar cell can generate enough power to charge the smartphone.
Do not depend on the battery
Under ideal conditions, a modified solar cell can generate about 50 milliwatts per square metre. This represents only 0.04 percent of the output that can be achieved during the day. But according to scientists, this is enough for LED lighting, for example, and once the technology becomes more efficient, it can be used smart home– Download tools.
The advantage of the invention is that users can generate power at night, without relying on a battery. Batteries are expensive and lose their storage capacity after a certain number of charge cycles. However, thermoelectric generators will never wear out, according to Assawaworrarit. “Life is practically infinite.”
Promising technology for poor countries
Although 50 milliwatts is not enough yet, Assawaworrarit is convinced that the technology can be greatly improved. He and his team believe production can be doubled with some modifications. “The theoretical limit is one or two watts. That’s not a huge number, but there are a lot of applications.”
The team mainly refers to people in poor countries, who often do this no entry Access to the power grid. These people can use the solar panels during the day, but during the night the options are more limited.
With the technology, Assawaworrarit and his team hope that these people will eventually be able to come up with a cheap and sustainable way to generate electricity at night.
