Harvesting Condensation / thaw?

Hi everybody,

Living in a mediterranean climate which has been very dry lately (hardly any rain even in winter), I observed that from around fall to spring, the air can be very humid and usually a fair bit of thaw amount in the morning ours on the vegetation.
How can I enhance and harvest this condensation? e.g. put wire mesh fences in between plants?

cheers
Lukas

Look up "Fog Nets" and "Fog Harps". Both are designed to harvest condensation from the air, exactly like you described. Both should give you some ideas on how to make a harvester for yourself.

Hi, Lukas!

I feel like this keeps coming up in conversation lately, but I'm having trouble remembering all the different projects we've talked about. I'll try! To aid you in searching, I believe anything used to harvest condensation would be called an "atmospheric water generator."

Here's a potentially very cool passive means of harvesting water from air using solar hydropanels.

Here's a paper on dew harvesting in the West Bank.

Here's an article on using a net to harvest fog in the Atacama desert, here's the Wikipedia article on fog collection in general, and here is a good article on using mesh as well as "fog harps" and more.

This is very interesting on using air wells to harvest and collect condensate, with a number of historical examples.

I swore I remembered the intricate and wonderful water collection and storage systems of the Nabateans incorporating an element of condensate collection, but I can't seem to find anything about it now. Can anyone else recall anything like this?

The other thing that's tickling my memory is a mimetic technology that I think I read about in Stefano Mancuso's The Revolutionary Genius of Plants, that I thought was copying an ability of an unusual desert plant from South Africa that only has two long leaves and uses them somehow to harvest moisture from the air. But again, I can't seem to find this again (I don't own the book -- I had borrowed it from the library). Does this tickle anyone else's memory?

Hi Beth,
Thank you very much for your reply!
Even tough I actually am in Chile, all I have is air humidity. The fog forms only relatively close to the sea, and I get almost none of it on my lot of land. I will have to look into all the research done around using dew.
I was looking into buying an atmospheric water generator, but a reasonable size will cost around 10k USD ...
Are you collecting dew?
cheers
Lukas

I had thought that even any passive method of harvesting moisture from the air would be called an atmospheric water generator, even if it was something like a net or air wells, but I may well be wrong. I would agree with you that suspending something like wire mesh or nets between your plants may well yield some condensation or thaw melt and would be worth trying if you already have materials around!

We don't collect dew yet. We live in a high desert, and most years we get around 13 in. (33cm) precipitation, which we do collect for all our uses around our homestead, from drinking to watering plants. We also harvest ground runoff using dams and seguias and plant in sunken beds filled with mulch to capture and hold any precipitation.

This year we essentially didn't get any summer monsoon, where normally we get the majority of our rainfall for the year during that time (normally it would have just ended, but our last rain was in early August, and it was one of only three or four small rain events we got all summer). Also, monsoon is normally our most humid season, when collecting moisture from the air might work best, and it was only very briefly at all humid this year!

We are running low on water and looking into other ways to get it. We have a lot of sun, so I'm thinking something like solar hydropanels might make the most sense, but we can't afford to buy anything like that either. I'm wondering if we could build something like the air wells out of local clay and mud and organic matter; or if our cisterns perhaps already create condensate on their outer surfaces that we could collect (I haven't observed this; it may just be too dry here right now). We don't seem to get much dew. We do sometimes get a bit of frost.

I think I read that a small amount of electricity in the fog harps would significantly increase the water harvest. I think MIT has a gel that absorbs water from fairly dry air at night and releases it when heated by sun during the day.