The great minds in science may have come up with the answer to keeping cool at home while keeping the energy bill to a minimum.
Xiaobo Yin, a materials scientist at the University of Colorado in Boulder, has released a paper that shows he and his research team at the university invented a film that can cool homes and buildings without the use of refrigerants and the power they require to run.
According to AAAS’ Science magazine, the film is made from transparent plastic embedded with tiny glass spheres, absorbs almost no visible light, yet pulls in heat from any surface it touches. Already, the new material, when combined with a mirror-like silver film, has been shown to cool whatever it sits on by as much as 10°C.
Xiaobo’s film is a passive cooling method and drew inspiration from previous work done by fellow researcher Shanhui Fan, an electrical engineer at Stanford University in Palo Alto, California. Shanhui’s heat-absorbing film was successful in cooling surfaces as much as 5°C, but was expensive to produce and was ultimately deemed an unviable option.
According to Science, Xiaobo calculated that glass beads about 8 micrometers in diameter would be greatly effective in absorbing infrared, and so went about acquiring batches of glass powder and mixing it with the materials that would go into making the plastic product. They formed the material into 300-millimeter-wide sheets and backed them with a thin mirror-like coating of silver, and found during testing that the bottom layer of silver reflected almost all the visible light that hit it:
“The film absorbed only about 4% of incoming photons. At the same time, the film sucked heat out of whatever surface it was sitting on and radiated that energy at a mid-IR frequency of 10 micrometers,” Science reported.
Xiaobo’s paper said the film can be made using standard roll-to-roll manufacturing methods at a cost of around 50 cents a square metre.
Due to this ability to be made cheaply at high volumes, it could be used to cool buildings and electronics such as solar cells, which work more efficiently at lower temperatures.
Image courtesy Y. Zhai et al., Science 355, 6325 (9 February 2017)