Sunday, July 8, 2018

Homemade and designed solar water distiller

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Another post in the water sub series in the main off the grid series of posts.

Originally posted 10.06.17, updated on,


Lately, I am thinking of using a 4x8 foot piece of glass-like substance, plus a few 2x4's, a plywood base, and some flexiseal.  Total cost would be over a hundred bucks.

The water has to be shallow, or it won't evaporate as fast.  I calculate about a quart per sq ft.  At 32 square feet, conceivably, I could distill up to 8 gallons a day.  I think that is too optimistic.  My goal is 4 gallons per day.   Such a device that I am thinking of should be sufficient.


A few ideas have sprung up in my mind.  I want to do this as cheaply as possible, right?  Okay, then why use studs and plywood?  I could use fencing planks and cardboard.

However, it must be waterproofed.  For that, I could use something a bit more expensive.

So, two fence planks, with a third one used for the two sides.  The bottom will be cardboard.  The third one can also reinforce the cardboard so that it can hold the weight of the water.  The dimensions would be about five feet by one feet by about six inches deep.

On second thought, it could be shallower, so that means cutting the planks in half lengthwise.  It could still hold plenty of water.

The reason for shallow water is that the heat will evaporate it faster that way.

Not to mention that the wood will go further.  Three planks may make two of these.


I am considering adding some copper tubing as a condenser.  How much would be necessary, and how can I make this as simple as possible?

I hate complications.  Especially when I have to execute them.  Simplicity is tough enough.

It comes in coils, so if I leave it in a coil while gradually let it rise higher.  It would have to be supported somehow.  Also, any condensation must drain back where it is supposed to go, not back into the water that I want to clean up.

Can put a separator at the end, with gravity sending the condensate into a collection bottle.  It can be like a gutter that runs from the top part of the distiller, down to where I want to separate the dirty water from the area where the condensate drains into it.  About a foot long piece of metal bent in half will do the trick.


An idea sprang up in my mind.  Why use plywood?  I can use 2x4x8' studs.  Cut them down to the size needed, and enclose an area that will hold about nine gallons of water.

I think the idea could work, so now I can think of how to optimize it.  What I mean is to add a condensation chamber to it, like the linked youtube presentation below.

Would it be worth it to circulate cold water through a tube, and let the hot moist air condense around that tube, thus increasing the output?  No.  Actually, you don't need to circulate water at all.  Just the air.

You could have a Styrofoam cooler attached to the distiller.  Hot moist air will be conducted into the cooler, but enclosed, as the moist air would be inside a tube that connects the distiller and the cooler.  The tube would be submerged inside the cooler, and the air would be circulated through the tube and back into the distiller to be reheated by the sun.  As the hot moist air cools, it will condense inside the tube, and can be collected.

This setup would require but a small amount of electricity to run the fan that circulates the air.


11:30 am:

Here is a professional looking application of this idea.  This version is demonstrated in a four part series on youtube.   Frankly, I do not want the kinds of complications he has, but some of his ideas are worth a try on my own system.

For example, he has a condensation chamber.  It is made of metal and attaches to the back of the basin.  There is also a mirror that will concentrate solar energy into the water, thus heating it up.

9 am:

More thinking on this has produced an upgrade upon the design.  The amount of air inside of the distiller is too high, meaning the performance is likely to be disappointing.  Consequently the design now is for the triangle to be cut down to a few inches instead of a foot high.

If I keep this up, it might get built before Christmas.  Hmm.  That was joke, but Christmas is just a couple months away now.

the original post follows :

This idea has been floating around in my mind for a few weeks now.  Time maybe to give it a shot?  Here is a preliminary design.  It is simple, but hopefully not too simple that it overlooks some important points.

I want to use the sun's energy and the earth's gravity in order to purify water, so it can be used over and over again.  Pardon the crudity of the drawing.  Perhaps there is a prettier way of doing it, but I don't care about such details.

I should add that the smaller enclosure should be tilted so that the condensed water will drain towards a small hole at one end.

This will require another inch piece be cut lengthwise so that it will fit inside the enclosure.  This will provide the tilt necessary so that the distilled water can drain out.

The enclosed area should hold 7 square feet  times 7/8 inch, which is about a 1/2 cubic foot, which in turn is about 7 and a half gallons divided by two.  Since the materials can make two of these, it can process up to 7.5 gallons of water at a time.

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