Two methods for passive cooling are introduced in this chapter, namely radiative cooling and cool paint. Radiative cooling makes use of the natural black-body radiation of everyday objects, combined with the atmospheric transmission window at mid infra-red wavelengths. Cool paint incorporates particles with sizes comparable to the wavelength of visible and near infra-red light, thus is effective at scattering solar irradiation. This chapter introduces the basic physics behind these phenomena, reviews recent development and use cases of these passive cooling technologies, and discusses their potential impact on reducing building heat envelope gain and air-conditioning usage.
Energy Saving Coating Materials, 2020, pp 113-131,