Scaled solar-driven atmospheric water harvester with low-cost composite sorbent

Abstract

The rapidly developing atmospheric water harvesting (AWH) technology can convert inexhaustible water vapor from the air into liquid water, which has become a highly potential technological solution for humanity to cope with water crises. Unlike the energy-intensive method of cooling air below the dew point to achieve water production, the sorption-based AWH (SAWH) system with adsorbents can achieve efficient water production above the dew point temperature in arid areas using low-grade energy represented by solar energy. However, current research of SAWH focuses mainly on small-scale devices, and practical verification with large-scale experimental equipment is still lacking. In addition, most of these verifications used auxiliary equipment to support the demonstration, and the expensive chosen adsorbent to pursue full-day adsorption capacity further limited the practical application of this technology. Based on this, from developing composite adsorbents to scalable solar-driven devices, this work proposes a complete technical solution to meet practical needs in arid regions. The developed low-cost composite adsorbent has an adsorption capacity of 0.52 g g−1 at 30 °C@60 % of relative humidity (RH), and its adsorption capacity can be significantly improved with the increase of RH (e.g., 0.97 g g−1 at 30 °C@80%RH), which is very beneficial for the utilization of high-humidity adsorption environments at night. The developed adsorbent, combined with a scaled device optimized by thermal design, achieved a high-level water production capacity of 355 g in a day and 0.74 L m−2 in practical field experiments.