The researchers say the technology could be improved with better components, and that it could potentially generate as much as 0.5 watts per square meter — about 20 times more than the device the researchers demonstrated — especially in hot, dry climates where the radiative cooling effect is the strongest. With that output, says Raman, a small setup on the roof of a home could provide enough power overnight to charge a cell phone or to light a room with LED bulbs.
"We think this is an intriguing demonstration of how the cold of space can be accessed as a renewable energy resource and result in modest yet usable amounts of electricity," says Raman. "We think it also could form the basis of a complementary technology to solar energy. While the power output will always be substantially lower than that of solar devices, this new technology can operate at hours when solar cells cannot."
For more, see " Generating Light from Darkness ."