Optimizing solar evaporation efficiency: integrating controllable water supply and efficient salt collection methods

Abstract

Solar desalination presents a promising solution for providing high-purity fresh water in regions lacking sophisticated energy infrastructure. Specifically, the efficiency of solar-energy-driven interfacial evaporation relies on achieving a balance between supplied solar energy and the energy demand for evaporation through water supply management. Another significant challenge for practical application is salt crystallization on the photoabsorber surface. To address these issues, two strategies are proposed: I) Construction of a three-dimensional (3D) solar evaporator that achieves a balance between supplied energy and the heat energy required for interfacial evaporation (demand energy) by optimizing the height of the support structure and II) implementation of a tunable two-dimensional water supply path made of cotton. This not only facilitates optimal water supply for interfacial evaporation but also functions as a salt collection layer, enabling efficient salt collection post desalination. With the specific design of the proposed 3D solar evaporator, our device achieves a remarkable efficiency, approaching its performance limit (94%) with an evaporation rate of 2.30 kg/m/2/h, along with efficient salt collection and scalability. This work presents a novel approach for fabricating a cost-effective solar evaporator capable of consistently delivering affordable fresh water in remote areas.