Integrating Passive Daytime Radiative Cooling into The Evaporation‐Condensation System Enhances Thermal Convection for Sustainable Evaporation and Condensation in Closed Boundary

Abstract Constructing solar‐driven interface vapor generation in closed boundaries holds significant potential for achieving sustainable goals in safe water access, but sustained efficiency losses due to latent heat accumulation and local solar scattering limit its scalability. Herein, passive daytime radiative cooling (PDRC) technology is integrated into solar‐driven interface evaporation (SIE) to ensure sustained water purification and collection. The vertical condensation wall with the porous P(VdF‐HFP) membrane facilitates rapid latent heat release and droplet shedding, mitigating latent heat accumulation and light scattering. This strategy induces the formation of temperature and humidity gradients in the closed boundary, sustaining the strong thermal convection process over extended periods. In contrast, conventional evaporation‐condensation systems exhibit significantly weaker convective intensity after prolonged operation. This process enables the PDRC‐integrated evaporation‐condensation system to maintain the high evaporator rate of ≈2.1 kg m −2 h −1 and vapor‐droplet conversion efficiency of 73.3% for over 12 h, whereas conventional evaporative‐condensation devices only maintain the evaporation rate of 0.78 kg m −2 h −1 and conversion efficiency of 56.8% at 6 h. This integrative design surpasses the traditional evaporation‐condensation system, offering a novel perspective for the development of continuous and high‐efficiency water collection systems.