Theory-guided solar interfacial evaporator designs enabled by quantified multiphysical transport phenomena via a coupled experimental–numerical approach

Understanding coupled multiphysical phenomena within solar interfacial evaporation devices is crucial for optimizing materials and device configurations, thereby advancing the engineering of high-performance water production systems. The quantitative assessment of optics, heat, and mass transfer offers guidance for the evaporator's material selection and optimal structural design. This work employs an integrated numerical and experimental method for high-fidelity prediction of evaporation performance under various material choices, device configurations as well as operational conditions. Meanwhile, the multiphysics model we developed was validated and corrected through dedicated experiments. Firstly, we optimized the wicking and light absorption properties and showed that weak wicking rates (θ = 89.85°) and appropriate absorption coefficients (α = 200 m−1) lead to half-full substrates for high evaporation efficiencies. We find that the benefit of low emissivity of absorber surface can only be observed at solar concentrations larger than 4 suns. Meanwhile, we find that by adjusting the ambient temperature, relative humidity and wind speed, evaporation efficiency can exceed 100 % due to the absorption of energy from the surroundings. This study provides a systematic understanding of the coupled multi-mode heat and mass transfer and light propagation mechanisms in solar interfacial evaporation systems, providing guidelines for the rational design for practical applications.