Water Out of Thin Air: Designing an Atmospheric Water Generator to Address Water Scarcity

Water scarcity is a significant and escalating issue that is currently affecting every continent on the globe. According to the United Nations, water usage has been increasing at more than twice the rate of population growth, and it is estimated that 4 billion people experience severe water scarcity during at least one month of the year [1]. Often, there is an abundance of water in the atmosphere, with nearly 12,900 cubic kilometers of water present at any time [2]. To take advantage of this water source, our solution involves the design of an Atmospheric Water Generator (AWG) that can provide water to areas with medium to high humidity. The design converts water vapor into a liquid while minimizing the amount of input energy needed. The Earth is known to have a relatively cool and constant temperature of around 55°F at shallow underground depths [3]. The design uses the ground as a thermal sink by incorporating an optimized underground heat exchanger. This is accomplished with a closed-loop system of geothermal piping configured in a helical arrangement and a circulating pump powered by a photovoltaic (PV) panel. This allows for a liquid coolant (water) to reduce in temperature and be utilized above ground. The above-ground portion of the system consists of a crossflow finned heat exchanger, which allows for the cooled water to enter and condense humidity in the air. Air at 26.7°C and 85% relative humidity is directed at a rate of 0.23 kg per second across the heat exchanger by a fan which is powered by the PV panel. The air cools as it passes the heat exchanger and allows for water to condensate, which is collected, measured, and recorded via a remote data collection system. The system generates 200 milliliters of water every hour. Parameters such as temperatures, relative humidity, flow rate, and atmospheric conditions are also collected to verify the design and to model data for other regions around the world. It is an innovative design that offers a unique solution to help alleviate water scarcity.