Friday, September 6, 2013

Solar Still

 {Article still under construction}

Im Designing a Solar Still and putting the whole thing up blow by blow on

I have had this idea going around in my head for a while, and I thought this would be a great place to work it...

I been trying to design a solar stilll (a device to extract drinkable water from seawater) using only 2 standard plastic softdrink bottles, with probably the use of just a knife.

Most shorelines around the world have bottles washed up in them, and just running through the various ways of putting them together makes my mind spin..

I will be putting forward my own designs in this thread.
I challenge anyone to beat my designs

Heres the challenge...
Produce enough drinking water from seawater to sustain 1 person
Produce a design that can be easily repeated.
Show proof the design works
Design is public domain.. the plan is to tell everyone in the world.
Use only 2 plastic bottles
Winner will be the system that produces the most drinkable water.

It is possible that this task is impossible.... thoughts?

First Try... Glad I didnt actually need a drink..

Based on a YouTube Vid... second post

From a scale of 0 (absolutely nothing produced) to 10 (industrial desalination plant)
This one scored 0.00001
Amount of drinkable water produced: Significantly less than 1ml

After 3 hours of direct, if slightly cloudy sunlight on my sunny morning balcony (which has in the past been compared to the chronicles of Riddick in terms of sunlight power) it got misty in there, but very little water actually appeared at the bottom.

I'm not even sure if the couple of droplets of moisture at the bottom of the bottle weren't there before :)

There are a couple of variables to play with here;
 - less water water in the cup next time?
 - maybe a solid or tinted cup would have heated up more..
 - maybe a tinted/painted bottle would have heated up more.
 - I had an issue with joining the top to the bottom, since I cut them where they were even, I will next time make the upper part slightly smaller so it slides inside the bottom part.

Second Try

Worked a couple of bugs out.

Produced about 5 mls of  drinking water (if that!)

Used some magic tape to seal it up a bit, just because I knew this one would suck, and was more looking for proof of concept..

Heres what I learned..

1) before you cut the top off the outside bottle, mark it, so you can orient the two parts to their original position re each other... to get a solid seal is vital (more pressure means more heat means more condensation)

2) The outside bottle should be as clear as possible, while the inside one should be as dark and heavy as possible (absorbs more light and bigger thermal mass).

3) A tool that can puncture would make the work alot easier especially if you are making a complex one.

4) Its not just the direct sunlight that does the work (although it does alot) leaving it overnight had (a small effect).

No comments: