In 2022 I interned at Uravu Labs, a startup that makes drinking water out of air. Not from a river, not from the ground. From the air around you.
When I tell people this, they usually assume it’s a dehumidifier with good marketing. It’s much cleverer than that.
How it works, simply
Air always holds some water vapour, even when it doesn’t feel humid. Uravu captures it using desiccants: materials that soak up moisture. You’ve met one before. It’s the little “do not eat” packet in a new pair of shoes.
The process goes roughly like this:
- Air passes over the desiccant, which absorbs the moisture.
- The desiccant is heated, which makes it release that moisture as vapour.
- The vapour is cooled in a condenser and turns back into liquid water.
- The water is cleaned, mineralised and ready to drink.
Using heat to release the water, instead of refrigerating huge volumes of air the way a dehumidifier does, is what makes it practical, especially when that heat can come from renewable sources.
The surprise
Here’s the part that broke my brain a little. I’d assumed the desiccant would be solid, like the beads in that shoe packet.
It can be a liquid.
A liquid that catches water. My first reaction was that this made no sense. How does a liquid pull water out of the air without just becoming more liquid? Then it clicks. Some salts love water so much that a concentrated salt solution will pull moisture straight out of the air around it. It gets more diluted as it absorbs. Heat it, drive the water back out, and the solution is ready to go again.
It’s one of those ideas that sounds impossible until someone explains it, and then sounds obvious. Engineering is full of them.
What I actually did
Small startup, so I did a bit of everything.
- Assembly. Tanks, fans, heat pumps and condensers, the physical system that makes it all work.
- Sourcing. Finding and buying components from vendors for the builds.
- Testing. Trying different desiccant densities and mineral salts to see what absorbed best.
- Sensors and plumbing. Setting up the instruments that measure what’s happening, and the pipes that carry what’s happening.
- Data. Charting temperature and performance data using AWS (Amazon Web Services) and Excel, so we could see what the machines were doing rather than guess.
What stuck with me
Startups don’t have departments. If something needs doing, you’re the department. That year taught me to be comfortable being the least experienced person in the room on Monday and the person who figured it out by Friday.
It also taught me that the best engineering often looks like a magic trick from the outside. Water from air. A liquid that catches water. Then you learn how it works, and it’s even better than the trick.