Air-cooled adsorption-based device for harvesting water from island air

Abstract

Adsorption-based, atmospheric water harvesting is a promising method for addressing water scarcity, which is a common issue in island areas, which often contain a large amount of fresh water in the air. Most existing adsorption-based atmospheric water harvesting systems usually require an additional cooling source, e.g., water-cooling, to cool the released humid high-temperature air below its dew point to harvest liquid water. To date, large-scale atmospheric water harvesting devices that use air cooling in such conditions have not yet been developed. Herein, we report a forced air-cooled proof-of-concept device for harvesting water from island air. Fabricated using 21 kg activated carbon fibre felt (ACFF)–silica sol–LiCl30, this device generated up to 7.7 kg of water (adsorption at 31 °C with 63% relative humidity) per day-and-night cycle, with a thermal efficiency (ratio of thermal energy to water conversion) of 0.37, using air cooling alone in laboratory-simulated island conditions. This study verifies the possibility of using air cooling to condense released humid air. It provides a flexible water generation solution for island regions with limited supplies of fresh water and power.