Designing Porous Polymers for Daytime Radiative Cooling

Abstract: Passive Daytime Radiative Cooling (PDRC) is an electricity-free method for cooling terrestrial entities. In PDRC, a surface has a solar reflectance of nearly 1 to avoid solar heating and high emittance close to 1 in the long-wavelength infrared (LWIR) transparent window of the atmosphere for radiating heat to the cold sky. This allows the surface to passively achieve sub-ambient cooling. PDRC requires careful tuning of optical reflectance in a wide optical spectrum. Various designs have been demonstrated for PDRC in the last decades, including emissive dielectric on a reflective metal substrate, and highly reflective paints. In the talk, I will present our recent studies on developing porous polymers with excellent PDRC performance. The high density of nano/micropores in polymer leads to efficient light scattering at the interface between the polymer and air, which effectively enhances solar reflectance and thermal emittance. High solar reflectance above 0.96 and high thermal emittance of 0.97 are achieved simultaneously. A temperature six degrees cooler than the environment is observed at noon in Phoenix. Moreover, the process is solution-based and highly scalable.
Keywords: radiative cooling; fluoropolymer; solar reflectance; thermal energy
Citation of Video Article:
Vid. Proc. Adv. Mater., Volume 2, Article ID 210149 (2021)
Full Video Article at www.proceedings.iaamonline.org/article/vpoam-2021-0149

[@kimlibera663]

My question is there enough of these materials to manufacture roofs or tiles or pavements that can be applied to distinct buildings to obtain this artificial albedo.

[@robertvandenberg2883]

Thank you for your video. The Nature article mentions the negative effect of humid air, here in Malaysia average humidity is: 80.5%. Is it still possible to use radiative cooling in Malaysia? Do you have any data on the efficiency reduction based on air humidity?

[@dotanwolf5640]

you need dry air because humidity will not let heat dissapete. evaperative cooling doesnt work in humid condition either. the nature article shows concrete steps next to "the material", concrete absorbs heat so what is the point?