Improving solar water harvesting via airflow restructuring using 3D vapor generator

Solar interfacial evaporation offers a promising solution to the global water crisis. 3D vapor generators (3DVGs) have shown advancements in evaporation rates and efficiency, yet the mechanisms behind this enhancement remain enigmatic. To elucidate these mechanisms, we develop a scalable origami-inspired 3DVG with double-sided peak-valley structures that exhibits a 43.2% improvement over conventional plane evaporators. Our comprehensive heat and mass transfer studies reveal that the enhancement is not solely caused by the well-established dark evaporation increase but also by airflow restructuring, which reduces vapor diffusion resistance and facilitates thermal energy redistribution. Moreover, in practical scenarios considering the sun position, the 3DVG exhibits a remarkable 31.9% enhancement in outdoor solar energy harvesting. In multiple 5-day-long outdoor experiments under varying conditions, our device produced water ranging from 1.088 to 8.863 kg m−2 day−1. These discoveries shed light on the fundamental mechanisms governing 3D evaporation enhancement and hold promising implications for practical solar desalination devices.