All‐in‐One Solar Interfacial Evaporation System with Highly Effective Heat Management and Water Collection

Abstract

Although solar‐driven interfacial water evaporation (SDIWE) exhibits a rapid evaporation rate upon exposure to the open air and solar‐to‐steam conversion efficiency close to 100%, the efficient freshwater collection from a compactly closed SDIWE system remains a big challenge due to the suppressed steam generation on high local humidity near the water evaporation front. Herein, a low‐cost and auto‐floating SDIWE system is capable of transferring the latent heat of condensation (LHC) to the water localized in the photothermal layer without any auxiliary facilities. It allows the limited liquid water to absorb the energy of LHC yet rejects the downward heat conduction from the photothermal layer. As such, the water in the photothermal layer can be preheated significantly, not only reducing humidity but also promoting vapor generation. Compared with the commonly single‐slope evaporator, the clean water productivity of the presented system enhanced by 130% under one sun irradiance. Benefitting from its long‐term stability and superior salt‐rejection function, the presented system shows great potential for sustainable and practical application in freshwater production using natural seawater.