It’s been a long time since I posted on this project. The last work we did was when we broke ground on a patio area with free pavers from the neighbor, then I changed jobs and I can’t remember much since then . I think that was about two months ago.
I won’t say that our need for water has declined since that time, even though the Governor may have already declared our drought over.
Making an atmospheric water generator has long been a passion of mine and living 30 minutes from the ocean I have to believe that there’s an endless supply of moisture in the air even when it refuses to rain. I’ve also been reading quite a bit around soil bacteria and am really wanting a source of water for the yarden with no chlorine.
This book is my current favorite on soil biology. Teaming with Microbes: The Organic Gardener’s Guide to the Soil Food Web, Revised EditionOrganic Gardening & Horticulture Books)
We’ve broken ground on the patio area but I haven’t gotten the pavers down. Here are some pics of my youngest helping clear the ground (doing most of the work) while I moved the dirt out in the yard and spread it around. In the meantime my patience ran out and I just had to see how much water I could get from the dehumidifier.
Without any further suspense, we got about 1.5 gallons in 24 hours. It took a lot of electricity but ultimately we’ll have this hooked up to a solar panel. We may have gotten more but the fins froze up. That’s 45 gallons a month if it does no better than that but I’m sure with some tuning it can do a lot more.
One of the problems in starting with an off-the-shelf dehumidifier is that it’s not built for this purpose. To get the widest range of operating temperature you pay more, and newer units are all computer controlled. The computer is great for keeping your house comfortable, but not programmed as an Atmospheric Water Generator (AWG). Ideally I think I need something programmed to stay in continuous operation without freezing, and it needs to work continually rather than stopping at a certain humidity.
Aside from working around that programming thing I have a lot of science problems to work through. I’m not sure what kind of metal the dehumidifier fins are made of and if there is any material leaching into the water. 1.5 gallons a day seems like a great emergency water source to run from a solar panel, but you’d probably want some kind of good filter before you drink it.
I will also need a battery to power the system overnight and that’s when I’m concerned it will keep freezing up. Night time is probably the best time for air moisture so that’s an opportunity for science to prevail. I also want to gravity feed the garden from the 250 gallon tank, and I’m not sure if I need to raise the tank up a little to accomplish that. Arg, Math.
The tank will get filled by rainwater during the spring, and topped off by this contraption. I’ll also need to control gunk in the water without adding chlorine. I read (somewhere) that hay in the water controls algae. Lots of things to learn on this project.
Closing thought: An emergency, solar powered AWG water supply sounds like a great business idea – you could also outfit an RV with it’s own source of drinking water. Or in our case, a used diesel bus that we use for camping. If you’ve seen anything designed for this, please post a link in the comments.
Water out of thin air, part 3 by Brad Rowland is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.