Ultraviolet durable and recyclable radiative cooling covering for efficient building energy savings

Abstract

Passive radiative cooling (PRC) is a zero-energy thermal management technology for efficient building energy savings. The polymer-based porous films are promising PRC materials, but their low ultraviolet (UV) durability and the lack of recyclability limit their long-term and widespread application. Herein, a recyclable polymer-based porous radiative cooling film with excellent ultraviolet durability is developed as the covering of building. Benefiting from the Mie scattering effect of porous structure and the strong infrared emittance of ethyl cellulose, the film demonstrates a radiative cooling capability of 10.6 ℃ at the solar irradiance of 510 W·m-2. The calculated energy consumption results indicate that the average cooling consumption can reach up to 429.4 KW·h, and 31% of cooling energy can be saved. Importantly, due to the conjugated benzene ring structure of styrene-ethylene-butylene-styrene (SEBS), the film can block most of the incident UV radiation and diffuse the absorptive energy by delocalization effect of electron clouds, thus the film retains a high solar reflectivity after a continuous UV exposure for 240 h. Notably, the film can be cyclic utilized by a simple nonsolvent-induced phase separation (NIPS) approach. This research offers a fresh insight into the design of UV-durable and recyclable PRC materials, providing a promising prospect for minimizing global building energy consumption and facilitating the development of sustainable building.