Electricity-free air-conditioner! How cool is that?
Engineers in the United States and Saudi Arabia developed a system that can dissipate heat in a certain direction and cool buildings without consuming electricity.
The study published on Monday in the journal Nature Sustainability described the system consisting of an inexpensive polymer/aluminum film that can absorb heat from the air and transmit the energy through the Earth's atmosphere into the outer space.
The aluminum reflects sunlight, while the polymer absorbs and dissipates heat from the surrounding air, according to the study.
The film is installed inside a foam box at the bottom of a specially designed solar "shelter" that not only helps to block incoming sunlight, but also beam thermal radiation emitted from the film into the sky, according to the study.
One of the innovations of the system is its ability to purposefully direct thermal emissions toward the sky, said the paper's lead researcher Gan Qiaoqiang at University at Buffalo.
"Normally, thermal emissions travel in all directions. We have found a way to beam the emissions in a narrow direction. This enables the system to be more effective in urban environments, where there are tall buildings on all sides," said Gan.
When placed outside during the day, the heat-emanating film and solar shelter could reduce the temperature of a small, enclosed space by a maximum of about six degrees Celsius, according to the study.
The shelter-and-box system is about 46 centimeters tall and 25 centimeters wide and long, so numerous units of the system are required to be installed to cover a roof, in order to cool a building.