Radiative–Evaporative Cooling: Mechanisms, Structural Design, and Applications

Global warming and urbanization have increased cooling demand, driving up air-conditioning energy use and electricity loads. Zero-energy cooling technologies are therefore essential for energy savings and emission reduction. Radiative cooling, as a typical zero-energy cooling technology, is highly influenced by environmental conditions. By introducing evaporative cooling, the dependence of radiative cooling on environmental conditions can be reduced, thereby effectively enhancing the system's environmental adaptability and cooling performance. This review summarizes radiative-evaporative cooling (REC) mechanisms and structural designs, and examines the effects of key environmental factors, including temperature, humidity, and solar radiation, on REC performance. It categorizes these strategies into functionally separated, functionally integrated, and interfacial-coupled structures, while discussing regulation strategies involving optical properties, hygroscopicity, and water retention to enhance cooling efficiency and environmental adaptability. Building on this, the review further discusses outline the latest developments in REC across the textile, agricultural, and construction sectors, as well as the challenges encountered in practical applications. By establishing a comprehensive framework connecting REC mechanisms, material and structural design, and practical applications, this review provides insights into the development of efficient, adaptive, and sustainable cooling technologies.