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Benefits of Tube in Jacket Condensers?

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I have been chewing over a question for nearly a decade now and, frankly can't come to a balanced conclusion. I would like to hear others' input on this:

What is the benefit of a tube-in-jacket condenser system over a traditional worm/coil and tub setup?

I have worked hands-on in dozens of distilleries over the years and beyond a doubt over-boil vapor release situations, that being where a loss of water pressure or similar coolant flow event, have been the most common and dramatic safety issue I have seen. I would bet that any distillery operating for more than 6 months has seen a vapor release of some sort due to the design of tube-in-jacket systems. I have brought this to numerous manufacturers and have been met with both incredulity and acknowledgement of the problem. A few have even offered reasonable, low-cost safety backup systems such as external vapor venting as a standard feature (looking at you, @Southernhighlander). For the most part, however, I don't see any system redundancy or failsafes in the vast majority of distilleries I visit or manufacturer designs I see.

So back to my original question. What, if any, specific and unique benefit does tube-in-jacket have over a coil designed with the same throughput rate?

Let's do this, nerds.

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Was an interesting read.

 

But this also brings in to question the negatives of using copper in the cooling section.  Years gone back it was understandable as to why copper was used.

 

So with SS shell & tube condensers .....Taking it a step further with the time of cooling being considered, this means that cooling water entry ought then always be in "counter flow" in both RC and PC.  Everyone generally does "counter flow" in PC but do "with flow" in the RC because of rising air bubbles in the cooling water.

 

It also potentially means wrt extending cooling time within PC of slowing down flow and extending PC length.

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i may  be wrong but in my mind it would depend alot on the type of still your running . a column with lots of copper contact may not see any benefit to more copper contact , but a pot still with a copper head and lyne arm may need more copper contact .

 i also think the big copper stills in Scotland were designed a long time ago when stainless steel wasnt available . now to change to stainless condensers  would have changes to the spirit profile . 

tim 

 

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16 hours ago, Quinta Essentia Alchemy said:

I would bet that any distillery operating for more than 6 months has seen a vapor release of some sort due to the design of tube-in-jacket systems.

I dont understand why you think one type/style/design of condenser would be more prone to a vapor release than another style.  A "loss of water pressure or similar coolant flow event" would cause the same concerns/issues with any type of condenser.  As others have mentioned, the benefit to a tube in shell (Gatling gun style) condenser is that its more compact vs a worm tube.

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So back to my original question. What, if any, specific and unique benefit does tube-in-jacket have over a coil designed with the same throughput rate?

Higher efficiency - Countercurrent tube-in-shell heat exchangers will have a higher overall efficiency than tube-in-bath.

Smaller Package - Tube-in-shell will be smaller, have more surface area, more efficient use of space.

Safer design - Multiple vapor/liquid paths mean reduced risk of occluding the single-path design of tube-in-bath.

Tube-in-bath designs are older, less-advanced designs, where the ability to create more efficient designs was not possible to to the manufacturing complexity involved.  Fairly easy to make a crude tube-in-bath condenser with soft copper and any container you might have.  Building a baffled tube-in-shell is going to require significant machining/welding.

I am of the community that feels that you should not use copper on the downside vapor path, so for me, a copper worm would not represent a good option.

The only advantage that a tube-in-bath/worm condenser has is that it can be easily/crudely made.

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9 minutes ago, Silk City Distillers said:

So back to my original question. What, if any, specific and unique benefit does tube-in-jacket have over a coil designed with the same throughput rate?

Higher efficiency - Countercurrent tube-in-shell heat exchangers will have a higher overall efficiency than tube-in-bath.

Smaller Package - Tube-in-shell will be smaller, have more surface area, more efficient use of space.

Safer design - Multiple vapor/liquid paths mean reduced risk of occluding the single-path design of tube-in-bath.

Tube-in-bath designs are older, less-advanced designs, where the ability to create more efficient designs was not possible to to the manufacturing complexity involved.  Fairly easy to make a crude tube-in-bath condenser with soft copper and any container you might have.  Building a baffled tube-in-shell is going to require significant machining/welding.

I am of the community that feels that you should not use copper on the downside vapor path, so for me, a copper worm would not represent a good option.

The only advantage that a tube-in-bath/worm condenser has is that it can be easily/crudely made.

All of the above is true, however many traditionalists will argue, particularly with Cognac, that a tube-in-bath or worm-tub type condenser leads to a slower step down in temperature (top of the bath is hotter than the bottom of the bath) and that the temperature of the distillate coming off the still will affect the flavor of the product. I believe, although am not certain, it is standard practice to watch both the temperature of the finished distillate and the proof, and it is easier to control that temperature with a worm-tub. We have both worm-tubs and a tube-in-shell. We use the worm-tub stills for brandy and mostly make American whiskey on the tube-in-shell, albeit not the only reason we use the stills for those products.

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26 minutes ago, Silk City Distillers said:

I am of the community that feels that you should not use copper on the downside vapor path, so for me, a copper worm would not represent a good option.

@Silk City Distillers I think I've heard this before, but don't remember why people felt that way. What is the reasoning?

Interesting note on counter flow heat exchangers, I recently read that a certain duck's vascular system serves as one, to help isolate the cold to it's legs when standing on the ice. 

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My experience in Cognac and visiting scotch distilleries that still have worm tubs aligns with what Tom says, they using them to produce a specific flavor not because they are easier to make. In Cognac, I know of producers who alter the temperature of the distillate intentionally depending on the volatility of the wine or spirit (similarly the wine distillation is condensed at a lower temperature than the spirit distillation). I'm sure you could achieve this with a tube-in-shell, although on our hybrid pot still it is tricky. I've also seen stainless steel worm tub condenser in chinese baijiu distilleries, although that might be because they are more simple to make.  

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6 hours ago, adamOVD said:

I think I've heard this before, but don't remember why people felt that way. What is the reasoning?

Tons of folks seem to be anti-plastic, figured the anti-copper team needed some support.  Copper is toxic after all.

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11 hours ago, Silk City Distillers said:

Tons of folks seem to be anti-plastic, figured the anti-copper team needed some support.  Copper is toxic after all.

We switched from a copper to a stainless condenser about two years ago, and I feel like it has had a positive impact on our product. 

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You can run caustic and acid through a stainless condenser/vapor path and get it pristinely clean, you can not do this with copper.  In addition, copper is going to require more rinsing after aggressive cleaning to wash away any additional copper ion/particulate that will make its way into spirit.

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On 3/15/2018 at 11:17 AM, HedgeBird said:

I dont understand why you think one type/style/design of condenser would be more prone to a vapor release than another style.  A "loss of water pressure or similar coolant flow event" would cause the same concerns/issues with any type of condenser.  As others have mentioned, the benefit to a tube in shell (Gatling gun style) condenser is that its more compact vs a worm tube.

Because the coolant volume and ratio to vapor in a water bath is significantly higher than in a tube in jacket. When a tube in jacket overheats the coolant, it takes mere minutes to get to a release of vapor. On the other hand, I have never seen a water bath even come close to overheating.

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It is my opinion that because copper salts are poisonous, it is best not to have copper tubes in the final condenser of a still.  I will only build one that way if the customer insists.  Also, because of the efficiency of tube and shell condensers, I believe that they are a much better choice over a coil condenser, however I will certainly build the customer a coil condenser and flake stand if that is what they want.  We currently supply a vent connection with all current tube and shell condensers built for distilleries no matter what the size of the still.  The vent connection will vent the vapor to the outside of the building in case the condenser cooling goes down.  We also strongly suggest that the customer have an ethanol detector in the vent pipe and inside the class 1 division 2 hazardous environment around the still.  Both of the detectors should set off alarms and or shut down the still if activated by ethanol vapors.

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On 3/15/2018 at 12:23 PM, Silk City Distillers said:

Higher efficiency - Countercurrent tube-in-shell heat exchangers will have a higher overall efficiency than tube-in-bath.

Smaller Package - Tube-in-shell will be smaller, have more surface area, more efficient use of space.

Safer design - Multiple vapor/liquid paths mean reduced risk of occluding the single-path design of tube-in-bath.

Tube-in-bath designs are older, less-advanced designs, where the ability to create more efficient designs was not possible to to the manufacturing complexity involved.  Fairly easy to make a crude tube-in-bath condenser with soft copper and any container you might have.  Building a baffled tube-in-shell is going to require significant machining/welding.

I am of the community that feels that you should not use copper on the downside vapor path, so for me, a copper worm would not represent a good option.

The only advantage that a tube-in-bath/worm condenser has is that it can be easily/crudely made.

What do you mean by "efficiency"? Assuming cooling fluid type and temp being the same, both condensers would run just as efficiently, i.e. require the same thermal capacity to condense the same vapor.

Tube in jacket are certainly smaller pieces of equipment, but when you're talking about equipment that routinely exceeds 10' in overall length, the difference between a 12" dia. and 36" dia. condenser is negligible. 

Multiple vapor paths would reduce risk of occlusion, but if there is occluding material in your condenser, it's not going to be the thing to save you; you're already screwed. I have never seen a still that does not dramatically reduce the vapor path at least once and usually multiple times before it reaches a condenser (lyne arms, columns, vapor baskets, etc.). I have seen a few tequila/mescal still earthenware designs that take spirit directly into a condensing apparatus of some sort, similar to an Alquitar, but still there was significant restriction of the vapor path going in.

I agree that most products should not see copper on the cooling side of vapor, however, Cognac, Armagnac and plenty of other traditional producers are adamant that this impacts flavor and aroma positively, so I'm in no position to doubt them. And I think it has much more to do with quality than tradition or primitive machining. They make changes to process in other areas; impingement burners as opposed to wood fire, for instance.

Your last statement may be true for illicit distillation, but many, many distilling processes both traditional and modern employ them and for good cause. One of which is intrinsic safety. Again, I have never seen a coil release vapor. If you've been distilling with a tube in jacket for any length of time, I would bet that you have, no?

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On 3/15/2018 at 12:36 PM, Tom Lenerz said:

All of the above is true, however many traditionalists will argue, particularly with Cognac, that a tube-in-bath or worm-tub type condenser leads to a slower step down in temperature (top of the bath is hotter than the bottom of the bath) and that the temperature of the distillate coming off the still will affect the flavor of the product.

This is a major quality argument for coils. Theoretically, this could be achievable with a stainless coil, but the reactivity of the copper in many brandy styles is seen as intrinsic to quality. I'm not sure I agree with this, but I also realize that they know far more than I do on the subject.

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I'm going to just bump the original question a bit here. 

The question of copper on the cooling side has been conflated a bit with condenser design. I appreciate the dialogue regarding copper precipitates, but the original question was regarding intrinsic design qualities. Copper in not intrinsic to coil condensers, even though it probably constitutes 90% of beverage alcohol still design of that style.

I have seen the word "efficiency" used here quite a bit, but I am not sure it is being properly used. A condenser will condense the vapor it is fed and require the same thermal capacity to do so. Some stills may be designed to run over a much longer period of time and have an appropriately-sized condenser tube that reflects that, but that is still design, not an intrinsic deficiency in the coil design itself. Could someone with more insight expand on this?

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19 hours ago, Quinta Essentia Alchemy said:

Because the coolant volume and ratio to vapor in a water bath is significantly higher than in a tube in jacket. When a tube in jacket overheats the coolant, it takes mere minutes to get to a release of vapor. On the other hand, I have never seen a water bath even come close to overheating.

Thats a fair point.

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2 hours ago, HedgeBird said:

Thats a fair point.

Right, and I bet you've seen that first-hand, right (no need to answer :~).  This is what prompted the question. Assuming all other things are equal (coolant temp, contact surface area, distillation running time, condenser material) is there any other specific advantage to a tube in jacket over a coil in tub?

I see a whole lot of dangerous condenser designs (imo) and very few manufacturers that are willing to even admit that this design is problematic. I think that this mainly comes down to lack of actual distilling experience, but without a serious failsafe system like @Southernhighlander installs standard, these condensers are woefully under equipped. I even see designs that are meant to be hooked up to a garden hose! 

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57 minutes ago, Quinta Essentia Alchemy said:

 Assuming all other things are equal (coolant temp, contact surface area, distillation running time, condenser material) is there any other specific advantage to a tube in jacket over a coil in tub?

It seems like quite a few have been mentioned.

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@JustAndy, I finally had a moment to read that link, thank you. Excellent insight into the quality considerations of various condenser styles and operation.

Just now, Silk City Distillers said:

Seems you made up your mind before you even posted the thread.

I am genuinely looking for input and insight I am lacking. For something to have become the de facto industry standard, there almost certainly is a reason beyond size or manufacturing ease. I don't know what that is. The article @JustAndy linked points out that quality was seen to suffer at certain facilities in Scotland after a changeover to tube in jacket (copper construction, no less). So if manufacturing is simpler and construction materials can be the same why was one adopted over the other? 

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44 minutes ago, HedgeBird said:

It seems like quite a few have been mentioned.

Yes, and thanks to all for that. This post is meant to aggregate peoples' experience and preference for one type of condenser, not to be antagonistic or assert that one is superior. I have personally found that coils are safer, but there are compelling arguments to be made for both styles and I want to hear them. In most of the comments above, the superiority of one style over the other has to do with the traditional materials used; copper vs. stainless. Eliminating that variable we get:

Tube in Shell Pros:

Compact size
Less surface area contact time (also a Con for certain spirit types such as Cognac or Scotch when a longer temp gradient is desirable)
Less chance of occlusion or blockage (though, as I mentioned earlier, occlusion of the condenser should never be an issue)
 

Coil Pros:

Better control of thermal gradient, especially important when using a reactive material such as copper.
Safety. Totally anecdotal, I admit.

I haven't seen this topic addressed on these forums before and want to understand all of the subtleties at hand. Thanks again for everyone's input.

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