Geospatial Climatic Factors Influence Water Production of Solar Desiccant Driven Atmospheric Water Capture Devices.

Atmospheric water capture (AWC) can provide clean drinking water in locations not connected to the centralized water grid for disaster relief, rural, military, and other applications. The atmosphere contains 14% of the equivalent freshwater volume stored in lakes and rivers and is universally accessible without pipelines or dams. A growing number of solar-based materials and devices to capture water vapor off the electrical grid have been reported, all of which assume varying relative humidity, solar irradiance, and desiccant materials (e.g., silica gel, zeolite, metal organic frameworks). This work uses Monte Carlo simulations and geospatial mapping to integrate material and system parameters from literature with United States spatial and temporal climate data to pinpoint key driving parameters for solar desiccant driven AWC and forecast atmospheric water harvesting potential (L/m2/day). Solar irradiance provides energy to desorb water vapor adsorbed to desiccants and determines maximum AWC capacity with respect to location and season; 4-8 L/m2 system footprint/day can be captured across the United States in spring and summer, while capacity lowers to 0-5 L/m2/day in fall and winter. Desiccants can be designed with Langmuir specific surface area >1500 m2/g and Langmuir constant (kL) > 0.1 to adsorb water vapor and meet these maximum potentials.