Architecturally-engineered scalable nonwoven evaporator with square groove morphology for solar desalination and thermoelectricity generation

Abstract

One of the effective ways to solve the problems of freshwater shortage and energy crisis is to combine solar-powered interface evaporation and use of waste heat to generate electricity. Although various schemes for the synergistic generation of fresh water and electricity have been proposed, the existing schemes still have problems such as low utilization of light and poor scalability. Herein, an acetylene carbon black-modified nonwoven fabric (ACB@NF) with square grooves combined with thermoelectric generators (TEG) and heat sink (HS) to form ACB@NF/TEG-HS multifunctional composite evaporator. The results exhibited that the unique square concave structure of the ACB@NF surface on the upper layer of the evaporator facilitated the reflection and refraction of light, which improved the utilization of light to achieve efficient light-heat conversion and allowed the transmission of steam, while the lower layer of the nonwoven fabric was used to ensure sufficient water supply and absorb the heat from the upper layer to achieve efficient evaporation of seawater. Under one sunlight, the evaporation rate of the ACB@NF/TEG-HS system is as high as 1.46 kg m⁻² h⁻¹ (4 times that of seawater), with the evaporation efficiency of up to 82.81%, and meanwhile, a 980.8 mW m⁻² power is generated through waste heat recovery. Outdoor experiments further validated its practical application potential by connecting four groups of this system in series to achieve 0.78 L m⁻² daily freshwater production and 853.64 mW m⁻² electricity generation. This study provides a novel approach to the development of scalable and stable solar-powered freshwater and electricity cogeneration systems.