Air condenser

[Swag]

If air is such a poor conductor of heat, why do we bother insulating our columns, or our houses for that matter? Why does your Thermos bottle have a vacuum chamber in it? Ever heard of the "wind chill factor"?
If you think I'm nuts, that's fine, but telling me I'm wasting my time, or I'm making a bomb, is a useless waste of bandwidth. I'm going to do it anyway because I enjoy experimenting. If you don't like it, don't read it.

Cheers,

[bellybuster]

whoah, easy there big fella

insulate our column... insulated or not, the energy in the boiler still overcomes the release of energy to the air. we don't all insulate our columns... I don't

insulate our houses??? really, go ahead, don't

thermos bottle?? key word vacuum .. a vacuum removes both conduction and convection

relax my man, never said you shouldn't, go ahead. Never said a waste of time, nothing that makes you smarter is a waste of time although history can earn you a few hours back.

also never said I don't like it. I just asked a couple intelligent questions that actually have intelligent answers.

"whats wrong with using previously proven concepts???" a fine question in my books

"The air cooled still has been tried and proven to be substandard to traditional cooling methods" absolutely true

"There are dozens of threads here and elsewhere where folks have tried it and failed.
I'm all for experimenting and tinkering but the data that is already out there is pretty hard to dispute. " also true, bordering on fact

getting upset because someone disputes your claim is counterproductive to your aim. Take what folks dispute and prove it false with physical data.

If you can design an air cooled still that performs as well as a water cooled one on the same economic level or better, I'm on board my man. I want one.
Take nay sayers like myself and slap them in the face with I told you so's. Bring it on

[Hound Dog]

I like seeing you trying this but you have to think that you must remove the same amount of heat that you are putting in. This is where just the few gallons that you boil off in a regular water cooled setup will heat many gallons of cooling water. That is a lot of heat to displace. If you run a propane burner under a keg, your "fairly warm" air coming off the condenser has to move as much heat as that propane burner blasting under the keg is transferring into the wash. It's a lot of heat to move with air. Not that it can't be done but it seems that you may need to scale up in size or get finned tubing as was suggested. Like what Shady has. Don't know how to make it into a reflux design. Massive deflag with multiple finned tubes going straight up?

Just tossing out alternate ideas. Of course you could just hook a little pond pump up to a trashcan full of water and.......

[shadylane]

It's the OP's experiment and he can do what he wants.
A air cooled condenser is doable. Just needs a lot of surface area.
But having a boiler that is unvented and has a valve on the output.
Is dangerous and future readers need to be warned that this isn't safe.

[skow69]

Hey Swag, I wonder if you could incorporate some heat tubes to some advantage there. I'm sorry I don't know diddly about them, just seen 'em in laptops cooling the CPU. They seem to improve the hell out of that. just a random thought.

[skow69]

This is what made me think of it. These are heat tubes, aren't they?

Image shamelessly stolen from Keg__jam

[skow69]

Goddamnit, Albert, you're just wasting time! Even if there was such a thing as a "space/time continuum" we already proved that there is no way in hell that gravity could affect it. Now quit screwing around and get to work on something possible!!!

[Swag]

This is what made me think of it. These are heat tubes, aren't they?

Yes, that is a very nice little heat exchanger. The copper tubes are way too small for a reflux condenser, but they probably work great on a CPU. Fins are indeed optimal, I'm just trying to find a way to incorporate them into my design. I don't have a full machine shop at my disposal, so I'm somewhat limited. Stainless gas tubes might be a good compromise.
I've got the new version cutout and machined, I just need to solder it up and make a new ABS cover. I also just increased my column from 2" to 3" with a piece of old copper pipe I had. I stuffed it with a combination of copper screen and SS pot scrubbers.
The wife is having company in on Sunday which may unfortunately cut into fabrication time. Life is a dance sometimes.

Cheers,

[shadylane]

Massive deflag with multiple finned tubes going straight up

That's what comes to mind when I think of a air-cooled reflux condenser.
With fan speed control or air-flow limiting to control the reflux ratio.

[Swag]

@ Bellybuster, I'm not pissed off my friend, just a little annoyed that's all. I'm not at all sure this thing will work, but I'm having fun building and trying it. I just like people to have fun along with me. People get so serious and negative at times it's a bit of a downer. No big deal though. This wouldn't be the first wild hare idea I've built which didn't work for beans.

Cheers,

[Hound Dog]

This wouldn't be the first wild hare idea I've built which didn't work for beans.

Ha! I have a scrap pile of reject parts myself.

[still_stirrin]

This is what made me think of it. These are heat tubes, aren't they?

If they're tubes, they're probably filled with a liquid coolant. I really bet they're solid copper (a much better conductor of heat than an air-filled hollow tube).
ss

[skow69]

Sorry, I meant to say heat pipe. [See, I told ya I didn't know shit!]

A heat pipe is a heat-transfer device that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two solid interfaces.

At the hot interface of a heat pipe a liquid in contact with a thermally conductive solid surface turns into a vapor by absorbing heat from that surface. The vapor then travels along the heat pipe to the cold interface and condenses back into a liquid - releasing the latent heat. The liquid then returns to the hot interface through either capillary action, centrifugal force, or gravity, and the cycle repeats. Due to the very high heat transfer coefficients for boiling and condensation, heat pipes are highly effective thermal conductors. The effective thermal conductivity varies with heat pipe length, and can approach 100 kW/(m⋅K) for long heat pipes, in comparison with approximately 0.4 kW/(m⋅K) for copper.

[skow69]

Zootalures/CC-BY-SA 21.5

[Swag]

Got the new unit tested today and it worked a whole lot better than the last one. I'd show you a picture, but that function appears to be goofed up here at the moment.
At about half throttle on the burner, which is where I normally run, the condenser knocked down at least 95% of the vapor. I know this because I shut down the output valve and observed the slightest amount of vapor escaping through the top condenser vent. I could also hold my finger over the vent and feel little or no pressure, and the vapor was barely warm. When I opened the output valve I got some vapor coming out, enough to get a small amount of product.
I would feel very confident now running this unit as a reflux condenser. It knocks down more than enough vapor to cause a decent amount of reflux. I have to say that in spite of a fair amount skepticism, air is indeed a perfectly good alternative to water.

Cheers,

[Hound Dog]

That is good to hear. If it almost knocks down water it will do the trick with your ethanol.

[skow69]

Congrats.

Now post pics and diagrams!

[Swag]

I'm trying to post some images, but keep getting the message "It was not possible to determine the dimensions of the image." Either something goofy is up with my images (some of which I tried to post that I have already posted elsewhere) or the site has issues. Anyone else having problems?

[Hound Dog]

Did you size them down to below 800? They won't post if they are too large. Paint is the easiest sizing software I know of.

[skow69]

600 x 750

Site seems to be ok.

[Swag]

Did you size them down to below 800? They won't post if they are too large. Paint is the easiest sizing software I know of.

There's something incompatible with my hosting site. I'll find another and repost.

[Drunk-N-Smurf]

I get the same result trying to use pics from Dropbox. I have tapatalk on my iPad just for when I post pics.

[Swag]

Ok got the image thing worked out. It's the same configuration as the first one except with a 2" column and 1" pipes running through. I also added a top vent (the copper pipe sticking out through the ABS). I also went to a 2" to 3" ABS adapter for the blower (it was 1.5" to 3")
The air ranged from warm out of the bottom pipe to fairly cool out of the top pipe, much the same as the first one. I ran it for about 20 minutes and the results were as described above.
It only took me a couple of hours to build the thing. Drilling the holes for the 1" pipe was easy enough with a step drill, although the curve of the 2" pipe meant that the drill could only go down so far until the next step was taking too much material away. There was a little finishing work with a Dremel tool before the pipes fit properly. You could easily build one for under $100.00 including the blower.
In the picture you can see that the output valve is closed and there isn't much coming out of the RC vent. It works.



Cheers,

[shadylane]

I like the vent. Here's a thought for getting more surface area.
Add 5 more pipes perpendicular to the ones you have.
Don't know if a paint drawing will get the idea across but here's a try.

[shadylane]

One more drunken thought and I'll probably figure out were I was wrong in the morning.
Packing a air-cooled VM reflux condenser with scrubbies could be a good idea.
The extra surface area and restriction might be an advantage.
Under 100% reflux conditions, when the VM valve is closed, the vapor has no choice but to go up the RC and rain back down in to the column.
When the VM valve is open, the restriction caused by the scrubbies might make vapor go out even an undersized valve.
These things might make a air-cooled VM still start acting more like a CM still.
With the wider range of reflux control

[Swag]

Good thoughts Shady. The crossed pipes would work fine, except for assembly. The pipes have to be soldered in first, then the column has to be inserted into the abs pipe and the whole thing aligned with the holes. It's tricky enough with a straight line. You'd probably have to cut the ABS pipe in half lengthwise, insert the column, then glue it back together.
Packing in the column would probably work, I may try it. Controlling the amount of reflux would be easiest with a blower speed controller, or possible a valve or bypass mechanism.
Looking back I should have mounted the blower right to the top of the 3" ABS column, instead of using the adapters. That would have saved height and money.
Like any new idea, building it is always an education.

Cheers

[carbohydratesn]

Glad to see it's working that well - if ti can knock down enough ethanol vapors, you've got yourself a pretty handy thing.

[skow69]

Congratulations, Swag, that's no small feat. I am impressed.

[Swag]

It shows that air is a viable alternative anyway. Water is better in a lot of ways, and I still have a Liebig on my still. If you're using water for the product condenser, you may as well us it for the reflux too.
If I were stilling in a cold climate it would make a lot more sense for me to use air.
I've been thinking about a modification for a Liebig that may also work for an air rig. I'll see if I can't solder something up this weekend and post it.

Cheers,