Improving Solar Vapor Generation by Eliminating the Boundary Layer Inhibition Effect of Evaporator Pores

Abstract

Solar-driven water evaporation is highly demanded in various applications. However, the pore structures of the solar evaporators are commonly randomly designed, which seriously hinder vapor diffusion and thus limit water producibility. Herein, the boundary layer inhibition effect is uncovered for the first time, and we propose that low-tortuosity channels with a reduced boundary layer thickness is adequate for breaking through the long-existing vapor diffusion limitation. As a demo, nature-inspired low-tortuosity channels are constructed for a solar evaporator. Due to elimination of the boundary layer inhibition, the vapor diffusion flux can easily escape from the evaporator, yielding an evaporation rate of 16.8 kg m–2 h–1 under a convective flow of 4.0 m s–1 and 1 sun irradiation. Moreover, the 3D radial interconnection of the channels enables stable water evaporation under an arbitrary direction of convective flow. Our work provides a promising solution to eliminate the boundary layer inhibition effect of a solar evaporator.