Study on the cooling energy saving potential of a novel radiative cooling paints in building application

College of Urban Construction, Nanjing Tech University, China

^* Corresponding author: kai.zhang.ch@njtech.edu.cn

Abstract

Passive radiative cooling technology has attracted much attention for its ability to obtain “free” cooling by heat exchange between objects on earth and outer space through atmosphere window. However, most of the existing radiative cooling materials are prepared in the form of thin films, which limits the application of radiative cooling in building since the films are lacking in scalability and the various building shapes. In this paper, we prepared a radiative cooling paint (RCP) with acrylic resin as the substrate, and mixed with ploymethylpentene (TPX), and silicon dioxide (SiO₂). The emissivity of 0.87 and reflectively of 0.92 is achieved in atmosphere window (i.e., 8-13 μm) and solar spectrum (i.e., 0.2-2.5 μm), respectively. To further indicate the cooling potential of the proposed RCP for its building applications, a two-floor single-family house is modeled using EnergyPlus. The cooling energy saving potential of the prepared RCP for applying on different surfaces of the building envelope is analyzed, and the influence factors for the application of RCP is discussed in detail. The results show that a significantly cooling energy saving can be achieved for the buildings painted with the proposed RCP on all surfaces (i.e., roofs and walls) in which the annual cooling energy consumption can be decreased by 15.8-31.2% comparing to the building with typical roofs and walls located at all five climate zones in China.