A new device is an anti-solar panel, harvesting energy from the cold night sky.
By harnessing the temperature difference between Earth and outer space, a prototype of the device produced enough electricity at night to power a small LED light. A bigger version of this nighttime generator could someday light rooms, charge phones or power other electronics in remote or low-resource areas that lack electricity at night when solar panels don’t work, researchers report online September 12 in Joule.
The core of the new night-light is a thermoelectric generator, which produces electricity when one side of the generator is cooler than the other (SN: 6/1/18). The sky-facing side of the generator is attached to an aluminum plate sealed beneath a transparent cover and surrounded with insulation to keep heat out. This plate stays cooler than the ambient air by shedding any heat it absorbs as infrared radiation (SN: 9/28/18). That radiation can zip up through the transparent cover and the atmosphere toward the cold sink of outer space.