I've posted here about the square foot solar cooker, and here is another of the many uses for it.
This is a solar alembic, or pot still, made from square foot mirrors, which can produce between 2 and 5 ounces of distillate on a lazy sunny afternoon.

Step 1:

It is not that great at making distilled water (without added reflectors as above), but can make essences, perfumes, and even ethanol.

Please note: it is illegal to distill ethanol except for fuel, and you must have a federal permit to do so. However they are not that hard to get, and our government is actually encouraging the citizenry to experiment with this which is why I'm writing. I am with a group who have one.

Here is the link for a permit, which you MUST have. You need to specify that you will be making alcohol for fuel on the permit application.
http://www.ttb.gov/forms/f511074.pdf

Step 2:

The Reflector

You need 3 square foot mirrors, about $7 at your hardware store to build the reflectors..

Step 3:

Put them together with duct tape (carefully) to make a half box.

Step 4:

You can run a bead of silicon along the seams.

Step 5:

Be sure to have some backing on the mirrors (as above) as they are dangerous to carry about. You can use cardboard, or even better a good wood backing for safety. Paint your wood with a good coat of shellac or paint to help preserve it in the weather.

Step 6:

Your 'mash' bottle, outer cover insulating jar, and collector bottle can be had with a little scrounging in the recyclable bin, or from your local bar or casino. For the outer insulator jar, I use both glass and PET plastic gallon jars. I like the PET better because it insulates just a bit more, and is lightweight and unbreakable.
Cut a 1 inch hole in the middle of your jar lid to allow the beer bottle to poke through.

Step 7:

The inner mash jar is just an old brown colored quart beer bottle, and the collector bottle can be any 12 oz glass bottle. You need a couple of corks with holes (from your local wine-brewer's hobby shop), and a 16 inch length of 3/8 copper tubing bent into an inverted "U".

The unit goes together as shown. Since you're not going to be drinking this, but are rather making fuel, you don't need to condition you copper tubing.

Step 8:

When you fill your inner jar with mash, be sure to leave enough space for expansion, or it will 'puke' on you and splurt a lot of mash into your collector jar. I fill my 32 oz bottle with about 28 oz of mash.

If you are distilling for ethanol, you are required to put a 'spoiler' into your collector jar. A bit of gasoline will make it unpalatable, however I have tried using rubbing alcohol, since I know what the proof (% of alcohol) is on that as per the label, whereas I'm unsure of gas.
So far testing proofs has been iffy, but I have learned to easily tell if the distillate is over 50%. Vodka, at a rating of 40% WILL burn. However, it takes a very good lighter, and some patience. It will burn though as I can attest.

Here is how i check to see if it's above 50%, which lights so much easier than vodka. It is a beer can upside down (I use fosters, since it will easily hold 10CC of fuel). Measure 10CC into the cup and light it. If it lights easily, you've got over 50%. After it burns out, measure the remaining water, and by some math you can figure out your %, or Proof as they say. (Proof is 2X the %)
If I have 4CC left over, then my distillate was 60%.
Try burning 10CC of 91% rubbing alcohol, and you can get a feel for proofs.
Of course the best way to test is to use an alcometer.

Step 9:

Since alcohol evaporates starting around 170 degrees (less here in the high desert) by the time your mash bottle hits boiling, most if not all of the ethanol will have been removed into your collecting jar. Of course, the less ethanol in the mash, the higher the boiling point becomes, so...as the unit works, and drives out the alcohol, it boils less easily. The cool thing here, is that the 3 square foot mirrors do NOT QUITE have enough energy to distill water. Therefor, when the alcohol is gone, it quits working. How marvelously convenient.
This is a set-it and forget-it device. Point it at just slightly South of where the sun sets, and it'll do all the work by itself. When it's distilled most everything, refill the mash jar, but pour the leftover mash onto your compost heap. Or you could perhaps water your plants with it, it is certainly sterile by this time.

Step 10:

And, it's pretty much weatherproof.

This post is not intended to nor does it wish to promote the illegal distilling of 'moonshine', but rather as a potential way for interested folks to learn how to make ethanol for fuel, or other non-alcohol products, including distilled water and essences as we progress toward sustainability and self sufficiency.
While some people dislike the idea of making ethanol from our corn and grains, the leftover mash is rumored to be a superior livestock food. And, why not glean some ethanol fuel out of it along the way if we insist on feeding grains to our cows? I believe the development of simple solar distilling can greatly improve the EROEI of ethanol, and perhaps reduce the cost by 60% or more.
Additionally with solar, there is no danger of flame ever catching the vapors on fire. It is flameless, if you don't count that great big ball of fire in the sky.