Design of Daytime Radiative Cooler Based on Porous Polymer

• 1、School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876

Abstract：Traditional cooling methods, such as air conditioning refrigeration, generally adopt gas compression technology, which not only needs electric drive, but also has a destructive effect on the environment. Daytimeradiative coolingrealizes the decrease of object temperature by mid-infrared radiation to transport thermal energy to extremely cold outer space through atmospheric transparent window while reflecting solar light, which does not require additional energy input and has positive significance for energy conservation and environmental protection.Polymer-based radiativecooler attracts more and more attention of researchers due to their advantages of simple processing and low cost. In this paper, we design and numerically simulate a polymethyl methacrylate (PMMA) structure with a large number of nanopores randomly distributed. By optimizing the structural parameters, it has achieved ultra-high emissivity in the atmospheric window and extremely low reflectivity in the entire solar band, and the net cooling power per unit area is as high as 119W at ambient temperature.The structure effectively alleviates the problems of backing metal reflective layer, excessive thickness and complex preparation of polymer radiators in the past.Thus, it has broad application prospects in building energy conservation and agricultural production. Besides, our study is helpful to provide theoretical guidance and reference value for the design of such polymer radiative coolers.

Keywords： radiative cooling atmospheric transparency window polymer cooling power