A novel solar-driven interfacial evaporator with multi-stage tunable liquid supply for efficient adaptive evaporation inspired by human thermal sweating

Abstract

Solar-driven interfacial evaporation (SDIE) systems exhibit excellent localized solar-thermal conversion capabilities but face limitations in liquid supply regulation, posing challenges for achieving efficient evaporation under varying solar intensities. Inspired by the thermal sweating mechanism of human exocrine glands, this study proposes an adaptive solar-driven interfacial evaporator (ASDIE) composed of a SA-g-PNIPAAm thermosensitive hydrogel and a lignocellulose sponge-based evaporator (LSE). By optimizing liquid transfer within each functional module, the ASDIE achieves a balance between liquid transport and evaporation rates under varying solar intensities. Experiments were conducted to evaluate the evaporation performance of the ASDIE. The results demonstrate that variations in the SA concentration within the hydrogel effectively regulate the water content on the evaporation surface at different surface temperatures. Under solar intensities of 0.5, 1, 1.5, and 2 kW/m², the evaporation rates of the ASDIE reach 1.04, 2.21, 2.92, and 3.70 kg/m² h, respectively, representing improvements of 26 %, 48 %, 48 %, and 48 % compared to traditional SDIE (TSDIE). Additionally, the ASDIE reduces the average total heat loss to 14 % through its multi-level supply structure and adaptive liquid transport capabilities, corresponding to a 39 % reduction relative to TSDIE. Finally, the potential advantages of the ASDIE in applications such as seawater desalination and solution purification are explored, leading to the conclusion that the ASDIE is a promising innovative device for achieving efficient evaporation under all-weather conditions.