Build a Simple Parabolic Solar Still




Introduction: Build a Simple Parabolic Solar Still

I published here awhile back about a simple solar still, and now I am playing with adding a parabolic as a heater. The old 3 mirrored one has had a lot of views (and hearts, thanks), and it works quite well with minimal care. However, as it takes nearly half a day to get a few ounces of distillate, I decided to play with an old satellite paraboloid, the one I use for roasting coffee.

The darned thing actually works, and pretty well, too. One of the problems with ethanol for fuel is that the EROEI, or efficiency as you will, is very low compared with oil and coal. Burning fuel to heat your mash or wines is probably the most energy intensive part of the process. Of course, if we can cut down on that (improve the EROEI) then it is possible to consider renewable ethanol as part of our energy mix.

Step 1: Some Considerations Before Starting

As you can see, the unit is the paraboloid, a 'mash' jug of an old brown quart beer bottle, a cork and length of copper tubing, and a collector bottle. This prototype shows sloppy work, in that the quart bottle is not well secured, and the collector bottle at bottom is setting on a stand. So, when it's time to adjust the parabola to track the sun, I have to lift off the lower bottle, move the parabola, and then move the stand and put the bottle back in place. Not very acceptable, and it is dangerous to be screwing around with hot bottles. Boiling hot bottles.

Also, note that I have placed the unit on a patch of dirt. That way if anything breaks, or catches on fire, it will hopefully be not so dangerous as on wood, for example. Please be aware that the collector bottle contents will get as high as 184 proof. At least that's my measurement for the first couple of batches.

AND NEVER set one of these hot bottles on a cold surface, or you may have hot and possibly burning alcohol all over. I DO have a fire extinguisher handy when I am playing around with this stuff.

Step 2:

The first test yesterday went well. I use about 28 ounces of standard cheap vodka in the mash jar, and it started boiling after about 15 minutes. It was an interesting boil, and it makes a bit of noise, too. You can see the bubbles clearly, however this photo was taken just as the autumn sun was going down -- you can see the shadow on the reflector. Also, I had to use a lower box to set the collecting bottle on, as the sun was dropping in the West, and the parabola had to be lowered.

The device gave out 3 ounces of distillate in about 45 minutes, and then the sun was gone. I should have started earlier in the day. However, this equates to 4 ounces an hour, which ain't bad IMHO. The still will just about double the % of alcohol as in the mash jar. IOW, if you put in a 15% wine, you should get out about a 30 to 35% brandy I am thinking. We all know, of course, that it is illegal to distill alcohol without a Federal Permit, and while I am with a group which has one, this test distiller was not done on that licensed property. I will henceforth make sure that any future distilling is also done there. I did however spoil the alcohol. You can do that by adding a spoon or so of toxic substance into the collector bottle. You can add some gas, or I like to use rubbing (isopropyl) alcohol. This is to keep the stuff from being drank, so that you cannot be accused of making 'moonshine', even tho' you actually have.

Step 3: Measurements and Recordkeeping

I use vodka in this test, because it is a known proof of 80, or 40%, it is consistent in that, and also it is fairly cheap, running about $11 for an offbrand bottle of 1.75Liters. At full recovery, this bottle of booze (which is just barely shy of 60 ounces) will give back in theory about 24 ounces of 100% ethanol, or maybe a quart of 80%. Of course we cannot get 100% without special methods, so I am shooting for around 80% (160 proof) which is certainly usable in an alcohol stove, and possibly in small internal combustion engines. (I will have to research David Blume's excellent book "Alcohol can be a gas" for more on how to do that, but I have read it can be done, and especially for small engines such as those used in chainsaws, etc.

Step 4: Cleaning Up My Act

Here I redid the copper line, using a smaller diameter pipe, and ran it toward the back of the parabolic. I just drilled a small hole into a new cork, and pushed the copper tubing into it. And then I shaped and secured the new copper line with a wire tie.

Now that the collector bottle is away from the focal point of the parabolic, I don't have to worry so much about it possibly igniting and blowing something up. It probably would just burn, but I don't want to find out. Also, this is going to keep the fumes from the ethanol away from the hot spot, which was, before, just above it. The stuff measures at 82% so I don't want it near anything potentially hot enough to light it. And that means no smoking around it.

I did notice yesterday during tests, that the collector bottle got really hot. As the moonshiners do, they have cooling coils, and divert streams to provide fresh cooling water, etc. All this is not necessary when you are distilling with the sun, because you do not have to worry about conserving the fuel to heat your mash. We are using nuclear fusion (sunpower) which, so far, is FREE.

Although it might increase the efficiency to have cooling coils, I eventually plan to put the collector bottle into a pan of some kind filled with water. And, to that pan I could add some ramen soup mix, some garlic, a bit of sesame oil, and make myself a bit of soup while the alcohol is being concentrated and collected. This will cool the bottle and heat my soups, which is just one of the permie added kind of things we should all take advantage of.

Step 5: Closing Thoughts

This photo shows how you can tilt the collector up also, and without moving the bottles too much. It will go up and down, and since it is all on a pivot, can turn left and right to track the sun. I would like to possibly add a small solar PV panel, and an arduino or some other system to automatically track the sun. As it is, I have to go out every 15 minutes or so and move the unit to follow the sun.

I am very pleased with this so far, as it is made mostly from recycled jars and stuff, and this is something I could use in the event of a disaster to create my own liquid fuels if for some reason our infrastructure breaks down.

A little bit of yeast, some water, and sugar and grapes or grains will provide the feedstock for this, and the yeasties will do all the work of making the ethanol. You can run wine through once, to get around 30-40% alcohol out, and then run it through once more to kick it up to 80% plus.

I would NEVER attempt to distill anything higher than 40% in this, since, as we know, 50% or more is very flammable, while vodka at 40% is not. That is perhaps why our vodkas are sold at that strength. And when you get your fuel distilled, be sure to store it in GLASS bottles, because the plastic bottle your vodka came in is not designed to hold very high proof alcohols. You will note in your liquor store that all high proof stuff is sold in glass.

If you do want to distill anything over 40%, then I suggest you use my little square foot mirror still, found here: , which will handle high proof stuff without the potential danger of high heat igniting it. This little guy only gets to just over boiling, and I would feel safe using it for high proof, not this parabolic one. Too much chance of harm.

I will add to this instructable as I learn more about this process. Thank you.


Step 6: Afterthoughts

OK, please do NOT consider making your own ethanol without getting a permit to make fuel. If you want to make distilled alcohol for consumption, that will be very expensive to get all your ducks in a row. If you already do have the required 'ducks', and are producing alcohol for consumption, please consider going solar for small batches of your custom stuff. This will probably make a very nice artisan's absinthe,, and you could get maybe 40 ounces of Hi proof stuff out of just one of these systems in a good long day of full sunshine. (BTW is works even in slightly overcast conditions as I found out today.) Good absinthe runs about $100 for 120 proof I believe. Also if you are a distiller, think about some nice solar brandies....

I am excited about the possibilities of solar distillation, since, if we use grains for this, we not only get our ethanol out of it, but the left over distiller mash can be fed to our livestock, chickens, pigs, etc., so this does NOT take away food to make alcohol (as the anti-corn fuel people claim), but this allows us to squeeze some valuable BTU's out of our grains without removing them from the food supply. I think even people should be able to consume the leftover mash, but that waits for another time for me.

Using the sun to provide the heat for distillation may become an important step for us all to start to get off of the consumption of irreplacable fossil fuels. This is something that needs to be address NOW, not after we run out.


Thanks, and BE CAREFUL OUT THERE....

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    8 years ago

    parabolic reflectors need to track the sun, and a regular glass jar is a poor material to use to capture the heat.


    Reply 8 years ago on Introduction

    baecker03, thank you for comment. Yes, most of us do realize that parabolics need to track the sun. The article does mention that fact, if I am not incorrect. Building a tracker is the next project. Or the one after that. But until then I only have to adjust it a couple of times an hour, leisurely.

    I must disagree with you that a glass jar is a poor material to capture heat. Perhaps a clear one is, but as you may notice I am using brown colored jars. They are an excellent, almost ideal heat grabber. The brown colored bottles work elegantly at their task. I will admit plastic works better, and you can read about that in my other instructables. So sorry, I disagree with your last comment and think you are partially incorrect.


    Reply 8 years ago on Introduction

    baecker, an afterthought. As you can see in step 5 photo, the parabola is mounted on a board, and there is a lazy suzan type bar stool swivel underneath it. So, it is easily capable of moving east west. A very small stepper motor could probably move it either way. Also, if you look, there is an adjust for raising and lowering the unit. Perhaps a screw-drive of some type would raise and lower it, again with a small dc motor. Like a screw jack? Anyway, you are welcome to add suggestions to the build...I would love to have your help in designing it. Thanks.


    8 years ago on Introduction

    OK, well I'm not going to touch the illegalities of this, you ARE using this to distill Water Right? lmao

    Glad to see Your using a Sat Dish. I always love a good re-purpose ! perfect shape for the job ! Great Idea :P

    On a side note Plz be careful and store it with a cover over it. that Dish is designed to receive msg's from space and converge then to a Single Point ! :P

    I heard of someone burning a shed down with something similar

    Have Fun; Stay Safe ! :D