Internally-cooled atmospheric water harvesting enabling improved productivity.

ABSTRACT

Sorption-based atmospheric water harvesting holds promise for alleviating water scarcity, but current prototypes have not shown significant increases in practical yields despite efforts in the enlarged engineering scale. This is due to weakened heat and mass transfer with a packed sorbent bed. In this work, the desiccant-coated adsorbers were employed to fabricate the water harvesting device that incorporates internal fluid for cooling and heating during sorption and desorption. Featured with an internal cooling effect, practical water productivity could be improved by 1.75-9.96 times with a low desorption temperature (45-62 °C). The continuous water harvesting system could produce 0.77-3.98 Lwater/kgsorbent/day with a thermal energy consumption of 7.7-30.4 MJ/kg in wide climates from 20 % to 80 % RH, providing a reference for device design in the engineering view. The demonstration revealed that using natural cooling in the sorption stage has great benefits in improving water harvesting performance, which can be integrated into the building sectors or a wider range of scenarios.