Passive daytime radiative cooling: Moving beyond materials towards real-world applications

Abstract

Passive daytime radiative cooling has emerged as a promising sustainable technique for meeting ever-growing demand for cooling across multiple sectors. Although a number of review articles have reported fundamental mechanisms and materials developments of daytime radiative cooling, reviews on its current and potential applications have been limited to specific scenarios such as building energy saving. Thus, to the best of our knowledge, here we summarize and discuss a comprehensive list of most current and potential applications of passive daytime radiative cooling to broaden horizons in this technology. First, from a materials perspective, we briefly summarize approaches to creating high solar reflectance and high emissivity in the atmospheric window of 8–13 µm. We then present applications in five major categories, each with several sub-categories, and discus each application with selective articles. Based on the availability of real-world demonstrations and developments in commercialization, we qualitatively assess the technology readiness levels of these applications, highlighting future directions that need more attention. This review offers one-stop access to a comprehensive summary of passive radiative cooling applications along with recent progress and future opportunities.