Phase change foam with temperature-adaptive radiative cooling feature for all-day building energy saving

Radiation cooling is an emerging energy-saving technology that requires a minimal energy input to achieve Radiation cooling is an emerging energy-saving technology that requires a minimal energy input to achieve passive cooling. To date, the majority of research has focused on maximizing the cooling power. However, a passive cooling. To date, the majority of research has focused on maximizing the cooling power. However, a powerful cooling performance may lead to overcooling at night or during cold seasons. In this study, we powerful cooling performance may lead to overcooling at night or during cold seasons. In this study, we developed a phase change radiation cooling material (PCRCM) with temperature-adaptive cooling features to developed a phase change radiation cooling material (PCRCM) with temperature-adaptive cooling features to meet dynamic cooling requirements. Polydimethylsiloxane was selected as the flexible thermal emission submeet dynamic cooling requirements. Polydimethylsiloxane was selected as the flexible thermal emission substrate, while boron nitride nanosheets were chosen as the optical fillers. Consequently, radiation cooling mastrate, while boron nitride nanosheets were chosen as the optical fillers. Consequently, radiation cooling materials exhibiting 97.5% reflectance and 94% emissivity were achieved. The phase change material (PCM) was terials exhibiting 97.5% reflectance and 94% emissivity were achieved. The phase change material (PCM) was then loaded onto the foam as an optical and thermal buffering medium. The obtained PCRCM exhibited 96% then loaded onto the foam as an optical and thermal buffering medium. The obtained PCRCM exhibited 96% reflectance in hot atmosphere and 82.6% reflectance in cold atmosphere, passively cooling through thermal reflectance in hot atmosphere and 82.6% reflectance in cold atmosphere, passively cooling through thermal emission and PCM endotherms during the daytime, and actively heating through PCM exotherms at nighttime. emission and PCM endotherms during the daytime, and actively heating through PCM exotherms at nighttime. Simulation and outdoor tests demonstrated that the PCRCM shows an excellent building energy-saving potential Simulation and outdoor tests demonstrated that the PCRCM shows an excellent building energy-saving potential in different seasons. in different seasons.