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Making an air well Answered

I was thinking about another fun project that draws water out of the air with just the sun's energy. I noticed the empty open vinegar bottle I washed and set to dry on my window sill accumulate more moisture every day. It was pooling water in the bottom after a week. The bottle shape is like a ball with a long spout. I read a little about air wells on the web, but they are very large structures. It would be fun to build a small one that would make a few glasses of water a day. Comments?

Here's one link Air Wells & Dew Ponds

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lexdav

20 days ago

A desert air well has a different design than a dew pond. Both work the same way. A dew pond has the following conditions. Located on the south edge of a 200 foot hill in the northern hemisphere. Grass or forest on the hillside or ocean supplies humid air flowing up over the pond as the night air cools. The hillside is warmed on the south side. The minimum size of the pond is greater than 15 feet for efficiency. A tree on the south side helps prevent a vortex from forming overhead. The last clay layer must be powdered before wet application. The depth is 25% of the diameter. The shape is more parabolic. The bottom is self repairing. The water circulates and is cloudy from the clay. The clay is in dust size plates and prevents algae. Rain runs off the top. The cloudy layer is heavy and resists eveporation. The surface is flat. Water is needed to create a volume to start the dew pond mechanism. If you use a plastic liner it needs a powdered clay suspension. Straw liners are used to prevent clay from cracking. Kneeding or working the clay liner helps to align the clay plates for greater strength. Thats all you need to do. The desert air well has a much stronger cooling mechanism. That method was forgotten by 2,600 or so years ago.

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lexdav

5 weeks ago

another air well nearby is rectangular and works. size about 15 by 45 feet. the center is algae free and the rest is thick with it. the center is a 15 foot round where there is circulation. the dew ponds that i have found using google earth archaeology are 200 feet up a hill. this rectangle is surrounded by old forest trees. the top is still open. the ends have cat tails. wildlife depend on them. plants and frogs exist from hundreds of years ago sustained in isolation. the machine will work in a box that is 12x12x18 inches. the large size of a pond is because you need to move a lot of air. an air well is filled with moving air. it is better to extract from a 3d volume than a 2d surface. if you are using a metal sponge for extraction or glass you need a hydrophobic surface. rainex beads up water. the result of an air well is distilled water in unlimited supply with no energy supplied. no moving parts except air and water. winter is harder to deal with. that is why you have a frozen pond big enough to last til spring. moderns are using expensive technology to try to extract water from air. it is extremely easy to get cold air and water in this starving world. the solution is hard for the human mind to understand. that is why the pond builders died out after thousands of years. dew ponds have not been reinvented for thousands of years. no one builds them because they don't wear out. my pond has been there 260 years. four times that is a thousand. when it runs out of heavy clay water suspension it will stop working and dry up.

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lexdav

5 weeks ago

dew ponds are at the tops of hills on the south side. the air rises in the evening through the forest or from a river or ocean. the depression is lens shaped and covered in straw on the bottom and a layer of powdered clay. depth at least four feet. look up you tube Dorsett dew pond in England. worldwide they are only in e. sussex, one on Ascension island and virginia. they are algae free. the one i study is 25000 gallons built 1760's. they are maintenance free. trees at the edge live 15 years and die. nothing grows in them. they exist no where else in the world. they do not fill with runoff or a spring. some rain but the rest from the air. jack and jill went up the hill to fetch a pail of water from a dew pond. never goes dry. from baal god of rain in baalbek city Lebanon, 6,000 years ago. a liquid machine made only by the pond builders. can you guess how it works? ;-)

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wiley.jackson.71

4 years ago

I was looking into this as a glass design graduate student in 2011. I was trying to develop a product that would collect fog, was portable and could be placed directly over crops. The design I came up with was too expensive to produce a prototype. But two years after i graduated I came up with a compromise; a car or minivan's back windshield mounted on a post using it's window wiper hole as the anchor point and turned in the opposite direction, (parabolic surface facing the wind) with some sort of gutter to collect the water and a hose to direct it towards the plants you want watered. I have yet to build one because we don't even get enough fog in SF anymore to be useful but if you do, that might work for you?

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Orngrimm

6 years ago

Thanks for the thread! I think the whole air-well-idea is very interesting! :)
A lot of informations about different approaches can be found on the web.

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btrias

6 years ago

How about a recipient with a hour-glass shape? The bottom half in the ground or insulated so the collected water is not heated again and the top half solar-heated. The question remains how to create air circulation.

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adrofig

9 years ago

I would try having a large bottle and a smaller bottle. Fit the small bottle inside the large one. Fill almost all of large bottle with water. Water cools slower than air so it will increase the rate of condensation. A metal cone could also be added to the smaller bottle to speed condensation. My idea was to have it put in a car and have the a/c run over the external of the reservoir to cool the water and then have it stored in the car for drinking water. If you did that it would solve bringing a water bottle in your car but then it getting warm.

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Gaius CorneliusGaius Cornelius

Reply 10 years ago

Let's try that again. See the Wikipedia article on air wells, its full title is:Air well (condenser).

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airwelldriller

10 years ago

I think existing airwells work by two principles. One type takes advantage of seasonal temperature differences; summer vrs winter. This type works by cycling the surface air thru pipes or rooms underground. The other "standard" type takes advantage of the difference in day/night temperatures. The salad dressing bottle appears to be functioning as this type of airwell. Dew on the windshield and "bridges may be icy" are examples of this type of air well. I suspect that "dew ponds" work on this principle. Dew ponds have a long history, perhaps dating back to the Neolithic. In "Naturalist on the Thames" the author described a dew pond that produced upwards of five acre-feet of water a year... unfortunately he didn't give the dimensions of the pond. Russell's "improved dew reservoir" is 900 square-feet and five feet deep; deep enough that it may work on the summer/winter temperature differential instead of the day/night temperature differential. Either way, it only produces a tenth the water recorded by Cornish in "Naturalist on the Thames".

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robbtoberfestairwelldriller

Reply 10 years ago

Awesome info, Thanks! I still have this project on my list and plan to do an instructable on it someday.

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trebuchet03

12 years ago

I came across this a few weeks ago....

Water Cone

Compact and lightweight - I think they can be stacked and I'll bet you can get higher efficiency if you insulate the bottom pan :) If I were to make one, this is the design I'd try to replicate :P

1-1.7L per 24 hours. That's 4+ to 7+ glasses per day :)

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PKMtrebuchet03

Reply 10 years ago

For added irony and "fight the powah" points, I'm sure you could make one of those out of the neck of a water cooler bottle :)

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robbtoberfesttrebuchet03

Reply 12 years ago

Would that setup draw water out of the air? I'm not quite getting it. Maybe if the caps were left open. I think the heat build up in the bottle makes water condense during the day and slowly exhausts the hot air, then at night the bottle draws in with cool moisture laden dense air for reheating and condensing the next day.

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trebuchet03robbtoberfest

Reply 12 years ago

Slaps hand to forehead... I misread what you were saying :P No, this you're supposed to pour in sour water (be it salt water or muddy water etc.) and then fresh water forms on the outer ring.

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robbtoberfestrobbtoberfest

Reply 12 years ago

Reading more on this, I would need a pile of rocks 10' sq and 8' tall to make .5 gal at day. This might be a lost cause for now. I can't put out that kind of effort right now, but maybe someone else can.

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bobolou2

12 years ago

where i live it is often very foggy sometimes in the morning. Perhaps if you strechted a thin peice of cloth between two poles with something similar to a roof gutter benaeth it. The water in the air would drip down the cloth into the gutter. You could put a bunch of these in series and get a considerable amount of water...... maybe i will try this.

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airwelldrillerbobolou2

Reply 10 years ago

You are describing a "fog fence". A fog fence uses two layers of plastic cloth between the poles. The water that beads on a single piece of fabric don't bead up enough to run off. Given the slightest eddy, the two layers of fabric rub against each other causing the water to bead up and run off. At least one village in South American gets its water from a fog fence. I'm not sure a fog fence is actually an airwell, since it does not manipulate the local temperature to harvest water where none would otherwise be.

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Kitemanbobolou2

Reply 11 years ago

I don't know if they still do it, but they used to "farm" fog on the Canary Islands.

The islands are small, too small to generate rain, but they do have foggy weather.

"A standard fog collector consists of a 1m x 1m frame raised 2m above ground level which supports a double layer of (locally available) polypropylene plastic mesh netting. As fog touches the netting drops of liquid water form, which run down the nets into gutters that direct it into suitable containers."

Link to fog-farming project on Lanzarote
Link to magazine article with image of collector

Apparently the collectors are good for several litres of water per square metre per day

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Patrik

11 years ago

Try putting some aluminum foil around the bottom of your vinegar bottle, to protect the accumulating water from getting heated up and evaporated again by the sun. What kind of material is the windowsill made of? I assume a marble windowsill would keep the bottle cooler than a wooden one, for example.