A group of engineers have designed a new system that, without consuming electricity, can help cool buildings in large cities.
Radiative cooling is a passive cooling strategy with zero electricity consumption that can be used to radiate heat from buildings to reduce air conditioning requirements.
The system is comprised of a special but affordable, low-cost material, a polymer / aluminum film, which is installed inside a box at the bottom of a specially designed solar 'shelter'. This film helps keep your surroundings cool by absorbing heat from the air inside the box and transmitting that energy to the outside.
The aluminum foil is coated with a clear polymer called polydimethylsiloxane. Aluminum reflects sunlight, while polymer absorbs and dissipates heat from the surrounding air.
Together, the shelter and box system designed by the engineers measures 18 inches, 10 inches long and wide.
“The polymer stays cool as it dissipates heat through thermal radiation, and can then cool the environment“Explains co-author Lyu Zhou, a PhD candidate in electrical engineering at the College of Engineering and Applied Sciences at the University of Buffalo (United States).
“One of the innovations of our system is the ability to deliberately direct thermal emissions skyward."Adds lead researcher Qiaoqiang Gan, associate professor of electrical engineering at UB.
The new passive cooling system addresses a major problem in the field: how radiative cooling can work during the day and in crowded urban areas.
Six degrees by day, eleven at night
When placed outside during the day, the heat-emitting film and sun shelter helped reduce the temperature of a small, enclosed space by a maximum of about 6 ° C. At night, that figure rose to about 11 ° C.
“What we have done is create a way that allows us to use the cold of the universe as a heat tank during the day”, The researchers concluded.
With information from: