DIY Solar Still

[Seamaiden]

This is the deal, I'm fed up. I'm fed up with the Mr. Clean water filter thingy that Dave cannibalized for me because it becomes spent in no time at all. I'm a little more pleased with the PUR filtration system, but I have to soak the filter first, then always make sure there's water going through it, gotta nurse it along, gotta pour that water into a larger bin to save it. So, I'm thinking, is there a better way to do this, since I have to store the water anyway?

The answer is, possibly, yes. A solar still. I don't want anything fancy, don't want to have to mess around with something like a parabolic reflector. I've seen pictures of solar stills being used in what appears to be India, looks like a black plastic tray that holds about 5-10gals, sides built up at the rear and sides so that a sheet of glass can be angled to allow water heated up via solar radiation would condense upon its surface, collect into drops, and drip down into another container.

It's natural, it's essentially free, and it produces what is one of the few purified water products around. Filtration cannot be called purified (or something like that, there's some deal about the language), but this can be. I think I would like something that produces about 10 gallons/week, doesn't have a huge footprint, is cheap and easy to construct. Storage itself shouldn't be a problem for too long, although I seriously want a cistern for rainwater, but that's another deal entirely.



So! Whaddaya think??
If anyone has any knowledge or information to share, I'd love to see it. I've got some pages saved, a couple of schematics, one doesn't use a huge footprint, but oddly enough uses a black bath towel (water surface area increaser? Plus maybe heats it up?).

 

[Seamaiden]

Jeez, no one? Am I really breaking new ground here?

 

[Gilfman]

yeah ive done it before .. but it was with school and i used salt water ... how much where u looking to evaporate?

 

[Gilfman]

i tried drawing it but i cant attach... simple concept
get one large container and one smaller container
pour water into large container
place in smaller container withs something to keep it in the center
place black garbage bag over large container and wrap something around to keep it still
place a small weight in center of bag .. making sure that the bag concaves inward
place in sun and wait

 

[Seamaiden]

10+ gallons per week. It's just well water, but it's really BAD water for putting on potted plants repeatedly, I need something for flushing, mixing ferts, etcetera.

I think we have some carboys that should have appropriate parts, but I don't know if I can convince my husband to let me use them outdoors.

 

[jimbizzzale67123]

I think thats a great idea especially in the hot summer just do a test to see how long it takes diffrent amounts of water to evaporate and condense on the glass. So this glass and the container would be air tight correct?

 

[jimbizzzale67123]

Some other filtration devices I have seen before on like National Geographic were with sand they use sand to filter rain water to make it drinkable, I was high when I saw it of course. I dont really know how sanitary it will actually make the water but just another idea.

 

[LoudBlunts]

stop playing, break down and buy a RO filter system


or why not start rain harvesting?

 

[hybrid]

here is your cheap and easy one............

I prefer the black pond basins you can get free from people on craigslist but hey, kiddie pools must be on sale right about now to get rid of them.

take kiddie pool and fill with water 1/4 way. Place bucket (plastic or aluminum NEEDS TO BE SHALLOWER THAN THE BIGGER TUB) in the center of pool or pond tub and a few CLEAN ROCKS for ballast to hold it down.

Now duct tape some 1mil visqueen or plastic painters tarping around the tub and place a small rock in the center of the tarp.

Black obviously works better

Sunlight goes thru the tarp, heat is trapped and evaporates water in pool or tub. Water condenses on tarp and follows the decline and collects at rock dripping into bucket.

Pure clean water, dont know how fast it will work but you could do say 5 5gallon buckets that are black or painted black with 2 gallon buckets in them. The heat absorbtion of the bucket will do the trick.

Have fun, this whole primitive resources thing will have you building solar panels soon enough.

 

[Seamaiden]

We certainly have plenty of black plastic. I've been trying to find more designs that don't take up a huge footprint, as I want this to go out on the deck extension my husband made for me (it's about 6'x7'). I found one design that's vertical, kind of a trip, seemed easy enough to make with scrap bits of wood. The old pond is a good idea, too.

stop playing, break down and buy a RO filter system

Because, you lose water for that you've gained, too wasteful. Not to mention that I believe the filters and resins would likely be exhausted very, very quickly.

or why not start rain harvesting?

We shall! When it rains.

 

[LoudBlunts]

pressurize the waste water and refead it back thru the RO???

 

[Seamaiden]

Why would I want to do that if I can use the sun to make the water first time around for free (once the still is built)?

 

[Ohsogreen]

Seamaiden.... I saw a show last year on The Discovery Channel, addressing water needs in poor, underdeveloped countries. In Africa, near the Sahara Desert a Peace Corp Engineering Student came up with an excellant design.
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Basically, he built a four sided pyramid about 4.5 feet tall, cut the tip of it off, turned it upside down over a small cistern, and they suspended it from four poles, with small cables to each corner. The material they used was a light weight local wood, covered with black plastic. The thing produced 1.5 - 2 gallons of drinking water daily on average. Since, both the inside surface and outside surfaces were black (and twice as much surface area) - the sun super heated them up. Then when the sun went down, the temperature difference, caused condensation, both on the inside and outside - with both dripping down into the cistern - which you could just use a big rubbermaid tub. It also helped channel rainwater directly into their cistern - filling it faster, since they tend to get short duration - heavy rain near the Sahara Desert. Just a thought - a small scale one could be fabricated quite cheaply & put to the test. Sorry, I don't have a diagram, but it's not a hard project.
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Hope this helps.....
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Keep it Real...Organic....
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[Seamaiden]

I can't picture this thing in my head, how would it work? It's awfully dry air up here in the Sierra.

I wanna see!

 

[Ohsogreen]

I can't picture this thing in my head, how would it work? It's awfully dry air up here in the Sierra.

I wanna see!

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OK....now Ohsogreen is far from an artist. This is from memory. You can install an optional shelf or shelves - to help things along. If you put a shelf or shelves in - put a little trap door on one side for access - to put in your water pans.
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Remember, that built this application for dirt poor people, with no money, no electricity, no water to speak of, living on the edge of the Sahara Desert. It's just a gaint, dehumidifer. The temperature differential when the sun goes down, it what makes it work. The pryamid is blazing, burn your hand off hot, in a matter of hours. When the sun goes, down - instant temp. differential - moisture drops form & presto... artifical rain.....
Plus since the engineer said this design maxamizes the temp diff., because the outside catches more relfected ground energy (thermal engergy) while the tops (wide angle) catches more of the suns rays directly - because it is such a wide angle.
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Hope this sad drawing helps.....
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P.S. - You could do a small scale model using cardboard & a black plastic trash bag. Then suspend that small pyradmid upside down - inside a bigger box (which would substitute for the four support pole) - with twine. Make the holding box a skeleton style box. By cutting the sides out - leaving just the outside inch or two - all the way around - strengthen with duct tape. Just a thought....

 

[Seamaiden]

Jesus, so this thing pulls water out of the air?? Sounds intriguing, I've gotta show it to Dave.

 

[teamsleep]

heres an article about the inverted pyramid

Dew-Catching Inverted Pyramid wins Arup Water Challenge : TreeHugger

 

[catincombs]

Teamsleep I clicked on your link and it's real interesting. Thanks for the info / link.
I really like these organic threads, lots of good ideas here.

 

[Seamaiden]

I like it because it melds with other areas of our lives. For instance, garbage and its disposal. Several months ago our trash collection costs went up to the point where we could no longer afford to have pick up service at the house (remembering we're rural). Taking it yourself doesn't net much savings, even though gas cost is lower because they're only 1.5mi. away.

What we did was this:

1) Father-in-law gets the recyclables, including those that give money, this is his cigarette money. He's responsible for gathering up all recyclables, though, because anything we don't have to PAY to dispose of is a savings right there (and we're already going down for his paying recyclables).

2) Paper goods: Depending on what it is, some gets burned, some gets soaked in water and put on the compost.

3) EVERYTHING ELSE, which actually isn't much once you stop using disposables (remembering we're very water conscious being on our own well) gets compacted in a CraigsList trash compactor that we paid $20 and a drive to El Dorado Hills for (the north side, it was a bit of a drive, but it was nice going up the foothills). We end up with MAYBE three kitchen trashbags full of trash per month now, whereas before we were producing that many bags of trash in two or three days.

It takes time and dedication, and we've got weird little piles of things in the kitchen every now and then, the compost bowl (I want something enclosed I think, and I wish the compost pile was closer to the house), and my F-I-L's recyclable area.. ugh..
It works.