Researchers have created a new rooftop cooling device that works under direct sunlight, without electricity, by emitting back heat radiation into space.
The authors have produced a multi-layered solar reflector made of hafnium dioxide (HfO2) and silicon dioxide (SiO2) that reflects 97 per cent of sunlight at a frequency called the ‘infrared atmospheric transparency window’ which doesn’t heat up the atmosphere and goes right back into the ‘cold darkness of the Universe’.
This device can cool underlying buildings to 5 degrees Celsius below the ambient air temperature and could help reduce cooling costs.
Original research paper published in Nature on November 26, 2014.
Names and affiliations of selected authors
