2023 ASEE Annual Conference & Exposition

It is estimated that four billion people worldwide experience water scarcity at least one month per year. At any given time, there are nearly 12,900 cubic kilometers of water present in the atmosphere. To develop a solution to water scarcity, we designed a system that extracts water from the air by condensing water vapor from humid atmospheric air using a heat exchanger. This heat exchanger is cooled by pumping water into the ground, using geothermal piping to reject heat into the soil. This closed-loop geothermal piping system was configured in a helical arrangement underground at a depth of 2.9 meters. Before implementing the system, we used Engineering Equation Solver (EES) and estimated the amount of water to be collected at 1.7 liters per hour when the soil temperature is at 18.0 C. We conducted two pilot studies in Costa Rica as proof of concept based on a location selected by local collaborators. The first test site proved unworkable when the physical location had a soil and air temperature gradient that was too small. The team then set up another experiment at another location where we simulated a cool underground environment by mixing water and ice in a tank. The physical on-site system is now collecting an average of 0.45 L per hour of condensed water when the average atmospheric temperature is 28.3 C, relative humidity of 81.64%, and a simulated cold underground temperature of 20.2 C. Details of the design, implementation, instrumentation, future work, the educational experience of an international capstone, and lessons learned are also presented.