Solar Still

K

Krieger

Joined
Jan 10, 2006
Messages
243
I was reading the SAS survival book again and I've always thought the solar still was quite an innovative method for obtaining water. There's also a variation of the solar still that can be used to distill salt water. Has anyone ever tried either of these methods for obtaining water? Did it work and how well did it work?
 
in my experience, solar stills dont work that well. the only place i could really see myself using one is on the ocean if i didnt have a desalinator. my buddy owns a boat and when he was cycling his survival gear out i got a chance to play around with one of these before:

solar-still_6648.jpg


it does work, but i think i'd have to float atleast 2 or 3 maybe even 4 of them to generate enough water to keep me going.


i've also tried making the tarp style solar stills where you dig a pit into the ground and line it with leafy greens + salt water or untreated water. it works alright but it doesnt generate that much water. than again when you're in a forest with a very thick cover, enough sunlight doesnt hit the tarp to help the transpiration.


i'd say this method may work in the desert but is probably a last ditch kinda thing.
 
I've made several, they do work. They don't generate a lot of water, but you have more than you started with. I think it is one of those things you should at least practice making a few times, like traps and shelters. You learn a lot in constructing and using one. The vegetation you use matters, as does location. I found more compact, damp soil works better that sand, and of course you want it in the sun. Large, soft leafed vegetation works best. You need to seal the sides good and you need to leave it sealed up at least all day. Try making one, all it will cost is a little time and a trash bag. I've also made them using buckets and salt water. It is a valuable concept to understand so you can apply it to different situations. Of course the enviroment and weather conditions play a large role in how well it works.
 
Some friends of mine made a solar still, I was there when they went to check the yield. I wasn't impressed.
 
You will expend more water making it than you will get out of it. Plus, in your kit, you need a large sheet of plastic, a collection device and a long tube for a straw if you can carry it all.

Transpiration bags take up less space, a bandanna tied around your leg takes up little space too. There are much better options than a solar still.

As for getting fresh water from salt water, boil a pot of salt water and have a cloth stretched a few inches over the top of the pot. The cloth will become damp with fresh water and the salt will be left behind in the pot.
 
I will third what Kevin and Danny said having built solar stills before. Too much sweat for a small return. Another element is how well it has to be setup to work correctly ~ while it "looks" simple it is somewhat complex and if you are already dehydrated to begin with...

Shame on books that don't warn the reader that solar stills are not worth it.

Here is something that looks promising for disasters based on the same principal.

http://www.watercone.com/product.html
 
k_estela said:
As for getting fresh water from salt water, boil a pot of salt water and have a cloth stretched a few inches over the top of the pot. The cloth will become damp with fresh water and the salt will be left behind in the pot.
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The first solar still I ever saw set up was at a maritime skills summer camp when I was a kid. The instructor built it out of a 48 quart cooler, a Styrofoam bait bucket and a disposable poncho. That is where I made one using an old bucket. We constructed those and baffled rain traps using items commonly found on boats. We left them for what I remember being 36 hours or so, guess which one had water in it. Even though it is relatively ineffective compared to other methods, sometimes other methods, like heated distillation or transpiration, may not be available. The concept works, and if you understand it, may come in useful someday.
 
abo4ster said:
Shame on books that don't warn the reader that solar stills are not worth it.
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Those same books 100% of the time were written by people who copied others and never tested their own information, obviously.

Skam
 
Hey Guys./.

There are many problems with solar stills.. They can works, however they don't produce as much water as you think they would..
Especially if the ground is dry...

If there is a leak anywhere, your efforts will be lost,, or at least slowed down..

A better method would be to evaporate the water from a living tree branch or plant of some sort. Put a clear plastic bag over a branch of leaves and tie/tape ot off tightly around the branch..

Much more effective in my opinion..

There's other ways to trap and capture moisture...

ttyle

Eric
O/ST
 
Normark said:
A better method would be to evaporate the water from a living tree branch or plant of some sort. Put a clear plastic bag over a branch of leaves and tie/tape ot off tightly around the branch..

Much more effective in my opinion..
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Yup,

Transpiration bags do work better. Solar stills however are another story.

Skam
 
I built one with my students a few months ago for a Science lesson. It worked pretty OK. We managed a small glass of water after 5 hrs of wait time, we used garbage bin liners. We are in a tropical country so I believe the amount of moisture (pretty high) in the ground contributed quite a bit to the end result. Adding vegetation into the pit did not seem to increase the amount of water collected by much. To be honest I was pretty surprised with the amount we managed to collect.

Azad
 
Dannyboy Leather said:
Well, I love aviators, military and civilian, and many of these fine folks have some of the best survival skills that I know of.
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My comment wasn't intended to disparage aviators in any way. What I was pointing out is the similarity your training had with theirs. The solar still seems to be taught in some military survival schools as a dependable way of gathering water, when in most circumstances it is not.
 
Dannyboy Leather said:
No, your post didn't strike me as such. My humble apologies for leaving that impression as my mind drifted back through time thinking of my fellow flyers.
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No apology necessary, sometimes it is difficult to convey the tone of our messages with the typed word, I find I have that problem with my writing with some frequency. :o I thought it likely I'd done it again and sought to clarify. I think your point regarding the motivation behind teaching the solar still to military personel is probably correct, analagous to teaching civilians to build a fire. Except where a civilian would most likely benefit from a column of smoke indicating his position, the same might not be true of a downed airman.
 
This is the type of thread that makes moderating easy. I am glad any confusion was worked out like gentlemen.
 
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