Rethinking the Role of Thermal Conductance in Radiative Sky Cooling: Materials and Applications

Radiative sky cooling has emerged as one of effective routes to counter the increasingly severe global warming and extreme weather. With worldwide efforts, this technology has witnessed significant advances in developing various cooling materials and implementing application attempts. However, the misconceptions of thermal conductance on cooling materials have significantly blocked the further breakthrough of this technology. This perspective aims to address this issue by elucidating the impact of thermal conductance on radiative cooling performance in two key applications: building cooling and personal thermal management. It is delved into the modulation of thermal conductance in cooling materials, focused on porous structures, heat-conductance structures, and tunable heat-conductance structures. Furthermore, the design principles for cooling materials is discussed, emphasizing low thermal conductance for building cooling and high thermal conductance for cooling textiles. To drive further breakthroughs in radiative cooling technology, challenges facing its implementation is highlighted and present this perspective on overcoming them.