diy solar

diy solar

Drinking water from thin air

B

bdamit

New Member
Joined
Jul 10, 2021
Messages
6
Hello
I am quite new here, but we have been succesfully relying on our family's small solar electric system for over a decade now, which I installed.

I bought a waeco solar fridge kit, constructed an insulated chest around it but never really perfected it, so presently it sits redundant...

My interest here is repurposing this 12V refrigerator's working parts to generate drinking water.
As one knows, when a refrigerator's door is accidentally left ajar, the humidity in the atmosphere covers the cold produce with water through condensation.
I wish to employ this side effect to generate clean drinking water.

Has anybody had experience with such a system?
I hope to start to experiment soon and post my results.
 
Study dehumidifiers. Usually used to dry the air, not to get water. They're energy hogs.
 
I think you'll find it's pretty inefficient. Take a look here, some interesting thoughts and discussion.
diysolarforum.com

Water filter preference

Was just reading up on making y own Berkey water filtration system using buckets and buying filters! Sounds like a fun project for small amounts of water usage for drinking. Has anyone done this? What size filter are you using Micron size wise and where is the best place to buy your filters?
diysolarforum.com diysolarforum.com
 
I remember watching a YT video where the guy said he was coming up with a system that could extract a few gallons a day.
From the very quick glimpse (he was looking at marketing the product), it looked like a big metal pan, probably cooled down in some way, to have condensation and collect it.
 
We went down this route a bit before putting up whole-house rainharvest for 'offgrid' capabilities.
There are 2 kinds of dehumidfiers - the traditional 'AC' compressor/coolant/coils approach and the chemical absorb/dry-out approach. Both yielded 1-2gal after 24hrs (4'ish kwh of power). The chemical one can operate in lower temps - e.g. we wanted water in the winter.
**And all this 'junk' about safe to drink? - just get a Berkey (in my opinion) and don't worry about it.

We have 2000sq ft of roof (water collection), 18inches rain (average) per year, and 3 x 2500gal tanks and can go 8months in a normal house off of these - way bigger bang for the buck :) Its simple - pump -> pressure tank -> 20micron filter -> 5 micron filter -> Class A UV and all is safe to drink right out of the tap. Or skip UV and go Berkey / manage the water you drink vs other - but our city required the Class A UV.
 
Last edited:
Hello and thank you for your replies. I understand it could be fairly inefficient but as as I have the material and lots of sun (plus a fairly high 85+ humidity) I was wondering about giving it a go, more for a fun project than anything else (and a way to produce emergency drinking water during our three month dry period).
As it stands, we have about 100 sq.metres of roof collecting 500-600mm of rainfall a year, going into our stone-lined underground cistern, built in the medieval period! We take out the water in a gallon bucket and fill demijohns. It works just fine, and we blast the full glass demijohns with strong sunlight.
Add some electrolytic and we're strong and healthy! We have the water laboratory tested every so often and it scores better than bottled mineral water.

So thanks for the input, maybe I'll just reduce the volume of the chest and enjoy an emergency workshop beer cooler instead.
 
Nube is the only brand i know of. It's around $1500 and i don't know if it'll work for me or you.

There was a guy selling a DIY system on cd, but i forgot his name.
 
Sparky said:
Nube is the only brand i know of. It's around $1500 and i don't know if it'll work for me or you.

There was a guy selling a DIY system on cd, but i forgot his name.
Click to expand...
This is the guy I meant:

droughtmasters.mysimplestore.com

The Traveler 10 Water Generator

The Traveler 10 Water Generator pulls moisture out of the air, purifies and cleans it, and turns it into fresh drinking water. Recommend verifying 30% or higher Average Humidity in your area. 1 Year Warranty.
droughtmasters.mysimplestore.com

I have not tested this system and I don't know if it's worth it, and I don't think you can buy it complete, though the dvd might be something you can get.
 
Dear @bdamit, welcome to the forum. Awesome inquiry.

It is indeed possible to efficaciously induce water to condense out of the air, and collect+filter the water in order to render it potable.

I have successfully extracted water from air using peltiers and only 10W input power.

The best numbers I could find online were 250-310Wh/Liter of H20 from air. That's the number to match or beat :)

Check out what this person did: https://hackaday.io/project/5103-smart-dew-point-water-harvester

The aquaboy is one such turnkey device that seems to be out of production now; it looked like a normal water cooler but inside it had a refrigerant compressor cooling mechanism that blew ambient air over a cold interface and collect the condensation in a stainless steel drip pan. UV light, water filters, and a final stainless steel holding tank.

I think if you want to convert a small fridge to do Atmospheric Water Generation that you can absolutely achieve some water generation. It will depend on your local atmospheric conditions. Basically, I would suggest finding as large of a water container as you can find that will fit in the fridge compartment. Fill it with some water/glycol mixture, and drill one outflow port and drill one inflow port. Run the fridge for a long time and then program an arduino to turn on a water pump when the ambient relative humidity is high and the temperature of the fluid in the reservoir is low.

Please ask more questions as you see fit. This is absolutely a tractable problem. It might not make you enough water to shower, but it's enough to prevent someone from suffering from acute dehydration if engineered appropriately.

To conclude this post, these other threads have some semi-related discussion for your optional perusal in the meantime:

diysolarforum.com

I'm interested in a hiked-in wilderness water collection setup using solar energy

My bestie and I have been trail building in the wilderness for quite a number of years. We have developed this one trail and cleared out a large area of undergrowth on the top of a majestic coastal mountain with an awesome view and call it Red Corn Camp. There is no water supply on the top of a...
diysolarforum.com diysolarforum.com

diysolarforum.com

WILL... I'm sorry but....

... PLEEEEAAAASE talk more about your plans for your dehumidifier water collection set up. do you have it planned out? are you still designing it? I'm SUPER interested in this. Bless up!
diysolarforum.com diysolarforum.com

This one mentioned earlier in the thread has great info about filtering water:

diysolarforum.com

Water filter preference

Was just reading up on making y own Berkey water filtration system using buckets and buying filters! Sounds like a fun project for small amounts of water usage for drinking. Has anyone done this? What size filter are you using Micron size wise and where is the best place to buy your filters?
diysolarforum.com diysolarforum.com

memory-alpha.fandom.com

Atmospheric condenser

An atmospheric condenser was a device that could extract water from the air. Kamin, a resident of Kataan, suggested building atmospheric condensers to fight the constant drought that was affecting the planet to his community's administrator. Each community would be responsible for its own...
memory-alpha.fandom.com memory-alpha.fandom.com

Cheers and have fun with whatever you do end up doing. (y)

From stacked peltier experiment 10W input power:
1626430546306.png
1626430554644.png
used about 5.5 Wh to draw 6 droplets out of the air in half an hour in 27°C ~37%RH condition. i would consider it a pretty shabby test, didn't get to the part of having a copper coil to carry the coolant and interface with the air.
 
Last edited:
Already posted about dehumidifier experiments above.

A big concern seemed to be bacteria etc - but a Berkey can take care of that, so it was mainly the power vs output that was disappointing. Might be better to power an EV and go to a creek and get 5 gallons in terms of power vs quantity :)
 
Last edited:
Yes this can be done. There is a bunch of kickstarters (Waterseer) that all try to do this. Problem is, it's extremely inefficient. Lots of power, very little water. Digging a hole into the ground gives more water then trying to extract it from the air.
 

Tsunami Products - Tsunami-500 ~ atmospheric water generator made in USA

Medium-scale atmospheric water generator. Water production rate: up to 120 gal (460 liters) per day. Perfect for homes, offices, schools, gymnasiums, hospitals, hotels, restaurants and other facilities. Tsunami-500 delivers water right to your own storage reservoir, fridge and/or integrated...
www.tsunamiproducts.com www.tsunamiproducts.com

apnews.com

In dry California, some buy units that make water from air

Some residents in the drought-parched U.S. West are turning to pricey machines that developers say can produce hundreds of gallons of water a day, literally out of thin air.
apnews.com apnews.com

i simply find it interesting that adoption is continuing
 
Sucker born every minute.

If that guy has the small unit, it cost him $30,000.
Lets say he is in a very humid area and it's making 400 gallons of water a day.

Average cost of water in the US is $1.50 for 1,000 gallons = $0.0015 per gallon.
$30,000 worth of water is 20,000,000 gallons.
At 400 gallons a day, it will take 50,000 days to make 20,000,000 gallons. Or about 136 years to pay off it's initial purchase price.

Anyone want to check my math? I might be off here.
 
for now the urgency is low

on the 5-10 year horizon i am taking small steps to mitigate the risk of increasing cost of usd per gallon of potable water.

one day i would like to be able to understand and maintain a system that derives consistently pure water from the air.

it’s not about doing things in the most inefficient way, at least for myself. it’s about having assurance of access to the essentials of life.

for now i still use the tap.

when the balance of cost between usd, kwh, gallon h2o changes maybe i’ll actually rely on a system that condenses water out of HEPA filtered air one day
 
You have that system now. Your AC unit on your house or car has a drain that drains away the condensation, aka water. You can go buy and off the shelf dehumidifier from BigBox store that does exactly what you are asking.

If the cost of energy falls so much, or the cost of water rises so high that extracting water out of the air becomes a "good" option, I am not sure what the world would look like.
 
Porch said:
You have that system now. Your AC unit on your house or car has a drain that drains away the condensation, aka water. You can go buy and off the shelf dehumidifier from BigBox store that does exactly what you are asking.

If the cost of energy falls so much, or the cost of water rises so high that extracting water out of the air becomes a "good" option, I am not sure what the world would look like.
Click to expand...
house and vehicle air conditioning generate non-potable condensate, not quite sewage but there is metal particles and critters often. definitely non-potable.

the house AC condensate drain hose has ran into the front garden for at least ten years, and it empties into a flower patch :)

as for car, i think it’s bogus that they make us refill the windshield wiper fluid tank when they could filter the AC condensate and replenish the wiper fluid with that water. cars need to replenish their tears somehow! (only half joking, of course it would add weight space complexity maintenance of different kind etc.. but i digress)

Atmospheric Source Potable Drinking water requires Air Filtration and Water Filtration, which every home/car AC i’m aware of does not do (it needs to be HEPA which some houses and cars have but it’s generally not enough.) The condensation surface also must be clean and Quite Corrosion Resistant. To prevent it from flaking off into the water supply. Some devices use Stainless Steel holding tanks and UltraViolet lamp in final holding tank to further discourage biological growth. Anything less than this and I would be very wary of the system suddenly becoming fowled.

Some members here have shown their AC condensate feeding their garden, and i think that’s just peachy keen.

AC condensate can severely harm a human if ingested, from my understanding, which could be flawed, either way good luck!
 
You are very correct. Buy the nature of condensing the water out of the air, you need air flow, and that will also collect everything floating in the air. So a filter is needed. Also available at any big box store in the form of a pitcher.

Just pointing out that
1) If you want to DIY it, the parts are available anyplace to do so.
2) This is nothing new or special, it just requires a massive amount of energy to do and it will never be near cost effective compared to digging a hole.
 
You must log in or register to reply here.
Back
Top