In a world’s first, researchers at %StanfordUniversity have developed %SolarPanels that work at nighttime.
Researchers at Stanford say they have modified commercially available solar panels to generate a small amount of electricity at night by exploiting a process known as “radiative cooling,” which relies on the frigid vacuum of space.
The research on nighttime solar panels has been published in the scientific journal “Applied Letters In Physics.”
“The coldness of outer space is an extremely important renewable energy resource,” said Shanhui Fan, the lead researcher on the project.
While the modified panels generate a tiny amount of energy compared with what a modern solar panel does during the day, that energy could still be useful, especially at night when energy demand is much lower. It also has implications for future space travel.
The modified solar panels don’t generate solar electricity at night. Instead of exploiting sunlight (or starlight or moonlight), the researchers added technology to the solar panels that exploits radiative cooling.
When an object is facing the sky at night, it radiates heat out to outer space, which means that an object can become cooler than the air temperature around it. This effect could have obvious applications in cooling buildings, but the difference in temperature can also be used to generate electricity.
Fan, a professor of electrical engineering, and his fellow researchers added technology to a commercial solar panel that could do just that and were able to generate a small amount of electricity at night.
The modified panel generated 50 milliwatts per square meter at night. While that’s much more than previous iterations of this technology, it’s well below what a commercial solar panel can produce during the day. In sunlight, one solar panel can generate 200 watts per square meter of power. One watt is equal to one thousand milliwatts.
Stanford’s solar panel modifications were made to commercial solar panels, which means the technology could be widely deployed. In time, and with improved design, more electricity could be generated at night, say the researchers.