condenser sizing

[HedgeBird]

Starting to think about the condenser for the 150 gallon / 11" column still I am building. I realize condenser sizing is related to heat input and not boiler size. My still is steam jacketed and I have a 325,000 BTU steam boiler. The still will be used for both initial stripping runs, and for final spirit runs. Currently I am considering an 8' long liebig condenser with a 1" tube and 2" shell (copper). My other though is to bump it up to a double liebig with 1" / 2" / 4" pipes with cooling water on the inside and outside and vapor running down the 2" pipe.

Would love any feedback/thoughts you folks are willing to provide!

[Artisan Still Design]

for that kind of heat input you're going to want a shotgun condenser. Liebig even at 1" will be way to restrictive.

[bluestar]

6" diameter shotgun, about 4' long, should work for you.

[HedgeBird]

so a 6" x 4' shotgun with about nine 1" through tubes sounds more appropriate? I just got done with my dephlegmator, and was hoping I could take the easy way out on the final product condenser. The good news is I think I learned enough putting the dephlegmator together that this build should go much easier..

[Artisan Still Design]

should do the job as long as you are running a high enough reflux ratio on your column.

[bluestar]

so a 6" x 4' shotgun with about nine 1" through tubes sounds more appropriate? I just got done with my dephlegmator, and was hoping I could take the easy way out on the final product condenser. The good news is I think I learned enough putting the dephlegmator together that this build should go much easier..

I would consider more but smaller tubes.

[Jedd Haas]

I would suggest you have an engineer calculate the actual cooling capacity of any proposed condenser. Start by calculating the square footage of the cooling tubes, then get the highest input water temperature (during the summer). Then determine the max heat input from your steam boiler, as you may not be using all 325,000 Btu. You might also look at your column size to consider how much vapor you'll be pushing out of the still, 11" can crank out a lot. Also consider other factors like your dephlegmator per VB's comment. (Of course that should be disregarded if you plan to do pot still stripping runs.) You need some actual numbers and calculations to get some greater certainty, although I agree with the comments above that you most definitely need a shotgun. But regardless, better that the condenser be too big, rather than too small. If it's oversize, you use less water. Too small and you get alcohol vapor or hot distillate. Also put some baffles in it to create turbulent flow.

[Dehner Distillery]

I'll build you a condenser no one could swamp. It is not just the type but the internal design. I'm not going to tell all my secrets but I could make 4' condenser act as if it is 20' long and you would use dramatic less amount of water.

Jolede029@yahoo.com

[HedgeBird]

As i had to buy a full stick of 6" ill probably just make it longer than 4' (something like 6') and go with 3/4" pipe instead of 1" to get more surface area.. I have a few ideas for adding baffles as well. Should be a fun build..

Thanks for all the feedback.

[nick jones]

I guess that I'm a little late to this party, but if you're still looking for advice, I'd go down to 0.5" pipe for dramatically increased surface area, and I wonder about the necessity of fabricating baffles (for a vertically mounted condenser). Your flow rate is going to be so slow that I'd think that you'd get all of the coolant stratification that you need thermally, but I've never tried it both ways, so don't take my word for it.

Also, this 6'x4" condenser is way more than you need for your BTU input. No harm in that (that I know of, at any rate). Better than too small.

Nick

[HedgeBird]

Thanks for the input nick! I will take a look at dropping to 0.5" through pipes and see what that looks like on paper. Perhaps I do that and skip the baffles..

[nick jones]

I thought of another consideration. If you want to use a thermostatic valve like the Danfoss AVTB to control your coolant flow (like those snooty Germans), you're going to want a thermowell INSIDE of your condenser (see attached picture). Otherwise, it is possible for the AVTB to close and not reopen unless you make a provision for a constant flow of coolant in your design. It is much more convenient to simply locate the bulb of the AVTB inside the condenser so that you don't need to worry about anything like that.

Nick

[HedgeBird]

I thought of another consideration. If you want to use a thermostatic valve like the Danfoss AVTB to control your coolant flow (like those snooty Germans), you're going to want a thermowell INSIDE of your condenser (see attached picture). Otherwise, it is possible for the AVTB to close and not reopen unless you make a provision for a constant flow of coolant in your design. It is much more convenient to simply locate the bulb of the AVTB inside the condenser so that you don't need to worry about anything like that.

Nick

I do have a Sterlco thermostatic valve I am considering using, but its probe is over 6" long so it would need to stick out the other side of the condenser if placed in the fashion you have shown. Your concern is that if placed outside/downstream of the condenser cold water around the well would never heat and open the valve as its too farm away from the vapor path/actual heat exchange? If i want to do a constant flow, I would need a very small amount of water constantly going through the thermowell, and then place the valve on a seperate full-sized coolant exit line? Another option might be to mount the thermowell vertically through the top steam chamber, and down into the coolant chamber?

[nick jones]

I attached another option for you to consider, and even added a convenient little indicator dial thermometer. The AVTBs have certain orientations in which they can and cannot be installed. I don't know if your sterlco is the same, but you might want to be sure that it can handle a diagonal mount like that before incorporating it into your design.

Your concern is that if placed outside/downstream of the condenser cold water around the well would never heat and open the valve as its too farm away from the vapor path/actual heat exchange?

Exactly.

If i want to do a constant flow, I would need a very small amount of water constantly going through the thermowell, and then place the valve on a seperate full-sized coolant exit line?

Right, except the valve would be on the coolant inlet (the bulb is on the outlet). But if you're going through all of the trouble of operating a manual bypass valve to begin with, you might as well just leave the condenser on full manual control; the thermostatic valve is going to add little to no convenience.

Nick

[Dehner Distillery]

Put in the baffles.