Advancing water collection efficiency in hybrid solar evaporators: key factors, strategic innovations, and synergistic applications

Solar-driven interfacial evaporation (SDIE) technique is a sustainable approach that utilizes solar energy to produce steam, thus addressing freshwater scarcity. Despite several earlier research investigations, claims beyond the theoretical limit were raised due to limitations in solar-to-vapor and condensate efficiency, which remain under debate. Even under superlative conditions, low condensate and energy losses persist, indicating that the system's efficiency will never reach > 100 %. This review primarily analyzes the theoretical values of evaporation rate, structural configurations, strategic approaches, and physical factors influencing condensate yields in the SDIE process. Using a theoretical energy distribution framework, this study identifies mechanisms driving conversion efficiency and condensate rate beyond equilibrium predictions, e.g., phase change process, and vapor-liquid equilibrium. Low water collection efficiency in condensation systems, driven by poor thermal management and inadequate surface designs, demands interfacial engineering strategies such as hydrophobic/hydrophilic coatings to enhance latent heat recovery and condensate yields, as briefly examined in this review. It emphasizes misconceptions about efficiencies beyond theoretical limits, purification challenges, and complementary applications while guiding researchers to provide plausible explanations for breakthroughs under specific and established reference conditions.