Iceberg-inspired solar water generator for enhanced thermoelectricity–freshwater synergistic production

Abstract

Interfacial solar steam generation has emerged as a promising eco-friendly and low-carbon emission technology to address the global water scarcity. So far, the majority of attention is paid to the improvement of the evaporation rate while the efficient vapor collection sector remains broadly unexploited. Herein, an inverted iceberg-inspired solar water generator (ISWG), consisting of a thermoelectric generator coated by a photothermal agent, a bilayer all-fiber nonwoven fabric and a passive cooling vapor condenser, is constructed. Inspired by the shape of an iceberg, the majority of the ISWG system is underneath the bulk water, leaving only the evaporation section floating on the water. This ISWG system not only avoids the vapor condensation induced solar input loss, but also transfers the heat to the surrounding bulk water, resulting in passive cooled and enhanced vapor collection. Moreover, a thermoelectric generator, which utilizes the temperature difference between the photothermal layer and evaporation layer, is sandwiched for thermal conduction in place of the traditional metal plate. The ISWG can achieve a high vapor collection rate of 1.02 kg m-2 h−1 and extra output electricity with a power of 0.47 W m−2 under sunlight with the ambient temperature at about 42 ℃. This work may pave the way for the development of an efficient solar-induced water-electricity co-generation system in tropical islands.