By exploiting the spectral overlap between this atmospheric window, corresponding to wavelengths between 8-13 microns and the range of thermal radiation emitted by buildings at typical ambient temperatures, the PDMS/aluminum film can effectively cool buildings during daytime. To fabricate the film, the researchers used a blade coating process to first coat the surface of an aluminum sheet with a layer of PDMS resin and then a metering blade to control its thickness, heating the structure in an oven at around 60 degrees Celsius for two hours to complete the process.
"Although the PDMS has low absorption in the solar wavelength range, we found that its radiative cooling ability was significantly impacted by the surrounding environment when tested outdoors, especially in crowded urban settings," says Qiaoqiang. To address this, the team developed a spectral-selective shelter that directs the thermal radiation toward the sky and achieved a daytime temperature reduction of up to 6.5 degrees Celsius in the outside environment.
The PDMS/aluminum film provides a low-cost and greener solution to cooling buildings in urban environments and can also be manufactured on a large scale, contributing to the potential commercialization of radiative cooling technologies. "We are now working on the optical structure of the film to enhance its radiative cooling, as well as its application in vapor condensation and water cooling," says Jian-Wei.
https://techxplore.com/news/2019-10-cool-alternative-air-conditioning.html
"Although the PDMS has low absorption in the solar wavelength range, we found that its radiative cooling ability was significantly impacted by the surrounding environment when tested outdoors, especially in crowded urban settings," says Qiaoqiang. To address this, the team developed a spectral-selective shelter that directs the thermal radiation toward the sky and achieved a daytime temperature reduction of up to 6.5 degrees Celsius in the outside environment.
The PDMS/aluminum film provides a low-cost and greener solution to cooling buildings in urban environments and can also be manufactured on a large scale, contributing to the potential commercialization of radiative cooling technologies. "We are now working on the optical structure of the film to enhance its radiative cooling, as well as its application in vapor condensation and water cooling," says Jian-Wei.
https://techxplore.com/news/2019-10-cool-alternative-air-conditioning.html
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