Modular all-day continuous thermal-driven atmospheric water harvester with rotating adsorption strategy

Abstract

Growing atmospheric water harvesting (AWH) technology is expected to provide a new solution to global water scarcity. However, the operating strategy of most existing devices is based on solar energy to adsorb at night and desorb during the day. The failure to operate multiple cycles results in the waste of fast sorption kinetics properties and increases both the required weight of adsorbents and the operating costs for the water production. Hence, by virtue of the fast sorption kinetics characteristics of Ni2Cl2(BTDD) with high water harvest performance, we developed a novel rotating operational strategy, in which one module works in the desorption, while the others work in the adsorption simultaneously and the adsorption/desorption states will alternate to keep the device harvesting water continuously. Notably, a continuous thermal-driven optimized device with three adsorbent modules was built, which can condense water vapor by simple natural convection without any auxiliary refrigeration system, generating 2.11 Lwater kgMOF−1 day−1 by 12 continuous harvest processes during the outdoor experiments, much higher than those of active AWH device with refrigeration system (0.7–1.3 Lwater kgMOF−1 d−1). Moreover, the proposed device can efficiently use electric heating or low-grade energy (e.g., waste heat) with natural cooling to achieve continuous operation, which can collect considerable water (1.41/0.70 Lwater kgMOF−1) at night/daytime.