After three years of work, the team felt confident they could build a device that would produce water for $. per liter; however, it would have taken significant development work and iteration to prove feasibility at $. per liter. Additionally, the next phase of work for the project looked to be heavily focused on hardware integration and mass production expertise — not X’s sweet spot. During the course of the project, the team also saw many new organizations — including research groups, startups, and NGOs — springing up to work on ways to harvest drinking water from the air.

To understand how the device worked, it’s helpful to go back to how condensation works in nature. When warm, humid air meets cooler air, or hits a cooler surface, the molecules in it slow down and cool into liquid. This is how clouds are formed in the atmosphere, or beads of water collect on a cold can of soda on a hot summer day. HE’s prototype basically replicated the natural process of condensation, but on a much smaller scale. This was made possible through a variety of processes and components — namely, constantly recirculating air, solar energy, and a desiccant (a material that absorbs moisture, like the silica gel packets you find in a new pair of shoes). The below illustration describes the process in more detail:

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Given these factors, it became clear that X wasn’t best suited to take the work forward, and one of the best ways X could have an impact now on the problem of access to safe drinking water was to share what we’ve learned.  We believe this technology, even at $. a liter, has the potential for positive impact in many communities and could form the basis for many viable businesses — just not the size and shape of businesses we’re working to produce at X.

After various iterations and user research studies, the team eventually built their most recent prototype model. This prototype ran on solar heat and was made from vacuum-formed parts — a manufacturing technique typically used to make small, disposable items, like takeaway food containers. Light and low cost, the team realized vacuum-forming also had the potential to form many of the larger parts of their device too.