Dual-Stage Atmospheric Water Harvesting Device for Scalable Solar-Driven Water Production

Context & ScaleAtmospheric water harvesting (AWH) using adsorbents is a source of decentralized drinking water, particularly where the moisture content of the air is low. Beyond adsorbent development, device-level improvements are needed to realize practical water productivity (L/m2/day) for solar-driven AWH. We developed a dual-stage AWH device using commercial zeolite (AQSOA Z01) where the two stages increased the productivity, and the latent heat of condensation was recycled from the top stage to assist in desorption of the bottom stage. In outdoor experiments using unconcentrated sunlight, we demonstrated that our dual-stage device had greater productivity than its single-stage counterpart. The dual-stage framework can be used with high-performance adsorbent materials and in different AWH systems to improve thermal efficiency. This work highlights opportunities for higher capacity and more efficient water production and opens new pathways toward scalable, lower-cost solar-thermal AWH systems.Highlights•Developed dual-stage device with daily water harvesting productivity of ∼0.77 L/m2/day•Demonstrated productivity can be twice the single-stage device by heat loss reduction•Provided model framework and guidelines to utilize higher performing adsorbentsSummaryRecent work has demonstrated adsorption-based solar-thermal-driven atmospheric water harvesting (AWH) in arid regions, but the daily water productivity (L/m2/day) of devices remains low. We developed and tested a dual-stage AWH device with optimized transport. By recovering the latent heat of condensation of the top stage and maintaining the required temperature difference between stages, the design enables higher daily water productivity than a single-stage device without auxiliary units for heating or vapor transport. In outdoor experiments, we demonstrated a dual-stage water harvesting device using commercial zeolite (AQSOA Z01) and regeneration under natural, unconcentrated sunlight where ∼0.77 L/m2/day of water was harvested. Our modeling showed that by further increasing top-stage temperatures via design modifications, approximately twice the daily productivity of the single-stage configuration can be achieved. This dual-stage device configuration is a promising design approach to achieve high performance, scalable, and low-cost solar-thermal AWH.Graphical abstract