writer：Liu, YM (Liu, Yanmei) [1] ; Bu, XH (Bu, Xiaohai) [1] , [2] ; He, M (He, Man) [1] ; Liang, S (Liang,
keywords：Passive radiative coolerSpectral selectivityThermal insulationFiber-reinforced aerogelsPorous architecture
source：期刊
Issue time：2023年
Passive daytime radiative cooling (PDRC) is an emerging energy conservation technology that spontaneously cools a surface by reflecting solar radiation and emitting excess heat to the cold space through the infrared atmospheric transparency window. A facile strategy to fabricate robust passive daytime radiative coolers based on thermally insulating and spectrally selective composite aerogels are demonstrated. The composited aerogels are constructed by P(VdF-HFP) matrix with abundant micrometer-scale air voids inside and surface modified chopped glass fibers randomly distributed in the porous polymeric matrix. Glass fibers act as skeleton are beneficial for enhancement of the rigidity, compressive strength, and flame retardancy of aerogels to satisfy practical PDRC applications. With a glass fiber mass ratio of 20 %, the aerogel can reach a high average solar reflectance of 0.951 and a high long-wave infrared (LWIR) emissivity of 0.954. By performing rooftop mea-surements, temperature decrease up to 8.05 degrees C is experimentally achieved under a high solar radiation (-946 W m-2) at midday time (12:00-14:00). The promising cooling performance comparable to those of state-of-the-art radiative coolers is attributed to the efficiently scattering ability of sunlight by abundant air voids, and the high thermal insulation property to weaken parasitic heat gain from the ambient air.