My new Liebig.

[rockystill]

Thank you!

[Alchemist75]

"High efficiency" lab condensers have a thin cooling medium annulus, so I tried a 19 ft 3/8" inside a 1/2" x 0.035" tube for a wort chiller and I chill 6 gal of beer to pitching temp in less than 10 min with about half the water it took with my 1/4" inside 1/2" cooler. Maybe making the outside of a liebig closer to the inside would have a similar effect?

I've brought this up in a couple threads but it hasn't seemed to get much attention. My observation, using lab equipment, is that the west condenser (a variant of liebig) works drastically better than standard liebigs. Having less space between the jacket and vapor tube DOES make a difference in a noticeable way. This principal has affected the way I build condensers any more. You can get away with rather shorter condensers using the west design. Why this is so I have my theories about but I'm no engineer so I'll leave it to another to say why. I only know it works.

[still_stirrin]

"High efficiency" lab condensers have a thin cooling medium annulus, so I tried a 19 ft 3/8" inside a 1/2" x 0.035" tube for a wort chiller and I chill 6 gal of beer to pitching temp in less than 10 min with about half the water it took with my 1/4" inside 1/2" cooler. Maybe making the outside of a liebig closer to the inside would have a similar effect?

....I have my theories about but I'm no engineer so I'll leave it to another to say why...

Well, I AM a mechancal engineer. And without getting too deep into the physics (mathmatics) of heat exchanger design, there are a few factors which when considered, will improve efficiency of the condenser.

First, heat is transferred OUT of the vapor through conduction through the walls of the heat exchanger’s vapor tube. The heat conduction is proportional to the surface area...that is, the diameter times the tube length. Yet the heat transfer is inversely proportional to the tube thickness. So, you want a thin wall vapor tube...type M instead of type L or type K (typical for copper tubing).

Also, copper is greater than 10 times better at conducting heat than stainless steel, with thickness being equal. But, often stainless tubing has a thinner wall which helps improve its performance.

Now, heat is transferred from the vapor tube(s) into the coolant fluid...typically water. And the heat is collected in the water through convection. Convective heat transfer is optimized by turbulence to a limit. Too fast of water flow will decrease heat transfer, yet water flow slightly greater than laminar flow will transfer heat best. So, slow flow with a narrow annular flow area will be the most efficient...less pumping power input and greater energy transfered.

Successful heat transfer will raise the water exit temperature nearly to the entry temperature of the vapor inlet. This is why counter flow exhangers are preferred...heat transfer efficiency.

But like the heat mixture in the water jacket, the vapor inside the vapor tube transfers its heat via convection to the wall of the vapor tube(s) (exposure to the walls) at which point conduction pulls the heat through the tube wall(s).

If the length of the heat exchanger has limitations geometrically, you can improve performance by using multiple tubes in a tube bank...a shotgun. Again, conductive heat transfer is proportional to the vapor tube diameter by its length multiplied by the number of tubes.

Also, vapor dwell time in the tube bank is increased as the vapor speed is reduced, allowing the vapor to transfer its heat (and condense) more efficiently. Too fast..and the vapor will puff through without fully condensing. And, increasing the water flow rate or adding ice won’t solve the excessive vapor velocity problem...only reducing the heat input to the boiler will help because you’ll reduce the vapor production/mass throughput.

So, vapor speed is a key factor for condenser design as well.

In summary, features to consider are:
1) vapor tube material,
2) vapor tube surface area (diameter x length),
3) vapor flow velocity,
4) coolant fluid (water) flow rate,
5) coolant flow regime (laminar vs turbulent),
6) counter flow design, and finally
7) the number of vapor tubes in the tube bank.

Kinda’ deep answer, but heat exchanger design is a fundamental course for a mechanical engineer. Sorry it seems so complicated...it’s the physics involved. But hey...at least we don’t have to consider radiative heat transfer here.
ss

[rootbeers]

Could the larger condenser be performing better due to the greater surface area of the inner tube and the increased amount of cooling water in contact with it due to the increased volume provided by the larger jacket?

Look up thermal conduction of stainless Steel and Copper.

Copper is the better thermal conductor over Stainless steel.

https://www.industrialmetalsupply.com/b ... cting-heat

ranks the heat conductivity of metals.

You notice that the best is Silver, the next best is... Copper... Where is stainless steel on this index, at 1. which is the worst.

1 = Bad, we're talking a cheap motel with onsite services, wink wink.
10 = Very Very good, so good, you take home to meet ya mamma.

[Hügelwilli]

The material of the condenser isn't as important as it looks.

The heat has to transfer three resistances:
1. The transfer to the inner pipe.
2. The transfer through the pipe material.
3. The transfer into the cooling water.

Those three resistances sum up.

This means the highest of the three has the most effect on performance of the condenser. While the condenser is condensing, the highest resistance comes from No.3 and while cooling the highest resistance comes by far from No.1.

This explains why also glass condensers work, although the heat transfer coefficient is such bad:
copper=380 , V2A=21 , borosilicate glass=1.2

[rootbeers]

The material of the condenser isn't as important as it looks.

The heat has to transfer three resistances:
1. The transfer to the inner pipe.
2. The transfer through the pipe material.
3. The transfer into the cooling water.

Those three resistances sum up.

This means the highest of the three has the most effect on performance of the condenser. While the condenser is condensing, the highest resistance comes from No.3 and while cooling the highest resistance comes by far from No.1.

This explains why also glass condensers work, although the heat transfer coefficient is such bad:
copper=380 , V2A=21 , borosilicate glass=1.2

I posted a link above that shows the top 10 metals in their thermal efficiency ranking, 1 being very bad, 10 being very good...

[Hügelwilli]

Did you read what I worte?
I wrote that the heat transfer through the material is less important than the two other transfers. Therefore the material of the condenser is less important than it looks if you only watch at the heat transfer coefficients of the materials.

[rootbeers]

Dependent on your set up needs I guess is what you are saying.

I have found that my Stainless condenser is less effective than the Lab glass and the Steam Distillation unit I have that is also Glass.

The distillation units I have that are Stainless steel retain heat too long and in the case of the water distiller unit, it cuts out when the things been running too long, something it shouldn't do.

There is an option that I don't think that people have considered and that is the materials used in the condenser composition, it is possible to have a copper inner with a stainless outer jacket, a case of "Sweating the joints together" like in HVAC systems that I have seen that have a mix of copper and aluminium pipes.

So there is another option open to people to consider, that is a "Composite Condenser" that is made up of the desired materials for the optimum performance.

[rootbeers]

Did you read what I worte?

I sea yew're paying attention...

[The Baker]

I had a stainless Liebig condenser.
Maybe five feet long, say two inch outside tube and one and a quarter inside. Vapour through the inside tube.
Got it free, it used to be a pre-cooler on a dairy farm, cooling the milk before it went into the refrigerated tank.
It seemed inefficient because of the big gap between the tubes so I stuck a copper tube down the middle to make it a Davies condenser.

'A Davies condenser, also known as a double surface condenser, is similar to the Liebig condenser, but with three concentric tubes instead of two. The coolant circulates in both the outer jacket and the central tube. Wikipedia'

Haven't tried it yet but it should be heaps better because of the extra water tube and the smaller gap.
But what I hadn't thought of is that the fact the middle tube is copper should improve it a lot too.

Geoff

[NZChris]

There is an option that I don't think that people have considered and that is the materials used in the condenser composition, it is possible to have a copper inner with a stainless outer jacket, a case of "Sweating the joints together" like in HVAC systems that I have seen that have a mix of copper and aluminium pipes.

So there is another option open to people to consider, that is a "Composite Condenser" that is made up of the desired materials for the optimum performance.

I have four, two are SS inside copper. SS inners because copper doesn't have a flavor advantage for a spirit run, copper outers because that what was lying around the shed at the time. The problem with using different materials is their different coefficient of expansions. One trick is to make a good, solid, reliable joint at the bottom, but design the top end to be able to move without a leak being a problem.

If you want to use SS for the inner and length is a problem, use thin wall tube.

[rootbeers]

I have four, two are SS inside copper. SS inners because copper doesn't have a flavor advantage for a spirit run, copper outers because that what was lying around the shed at the time. The problem with using different materials is their different coefficient of expansions. One trick is to make a good, solid, reliable joint at the bottom, but design the top end to be able to move without a leak being a problem.

If you want to use SS for the inner and length is a problem, use thin wall tube.

I have to point out that your claim to not have a flavour advantage using Copper, it is very important to use copper, there main reason is a chemical reaction one that certain chemicals can form in the still and distillation causes new compounds to be made. Copper... neutralises that process to prevent something more dangerious coming out the still... CYANIDE. https://onlinelibrary.wiley.com/doi/pdf ... .tb01031.x

Besides methanol, there are things like Acetone which is to any chemist, a reagent that is used in the formation of the very substance that I stated above. Acetone is a naturally occurring alcohol as is methanol and ethanol and all the 30 or so alcohols that are present in a still while distilling.

I am no chemist or chemical expert, that was my dad with the degrees in that stuff. Think of Alcohol like Oil, in the Oil distillation industry you pull all sorts of compounds out of it.

So its a warning to others who think that the only things in grain mash is alcohol and methanol, theirs way more. I don't want to offend anyone by sounding preachy, I am a bit concerned over this aversion to copper. It is after all important and has nothing to do with flavouring.

As for best metals... I posted a "best" chart with the ranking 1 = worst = stainless steel, to the 10 = the best = silver and at 9 is... copper.

making a composite condenser is fairly simple, if you have the equipment, strong joints would be as easy as silver solder as that would be more than enough to keep the joint solid. The copper pipe, again, easy, get a section with the ripples in to allow a "bellows" stretching action for take up in thermal expansion differences.

Engineering is also in my family blood as is electronics, legal, doctors, teachers and chemistry professors. You will begin to understand why my interests are so wide and varied.

Remember... COPPER IMPORTANT please use it and I am not intending on teaching granny to suck eggs here, so please don't feel offended by anything I say, I want to get across something that is important.

[NZChris]

I have to point out that your claim to not have a flavour advantage using Copper....

Read my post again, then read that research again. I only use my SS Liebigs for spirit runs.

Also see: http://onlinelibrary.wiley.com/doi/10.1 ... 0450.x/pdf

[rootbeers]

I have to point out that your claim to not have a flavour advantage using Copper....

Read my post again, then read that research again. I only use my SS Liebigs for spirit runs.

Also see: http://onlinelibrary.wiley.com/doi/10.1 ... 0450.x/pdf

The take away I got from the paper was that Copper is better. Stainless introduces things that you don't associate with drinking spirits.

[NZChris]

That research was done on a continuous distillation using a Coffee still. If that is what you’re running, I recommend you don’t use a stainless Liebig. All of my strips are done using copper Liebigs and only the spirit runs use stainless.

[Twisted Brick]

I have to point out that your claim to not have a flavour advantage using Copper....

Read my post again, then read that research again. I only use my SS Liebigs for spirit runs.

Also see: http://onlinelibrary.wiley.com/doi/10.1 ... 0450.x/pdf

The take away I got from the paper was that Copper is better. Stainless introduces things that you don't associate with drinking spirits.

Since the Barry Harrison (and Olivier Fagnen, Frances Jack and James Brosnan) study was published, a number of well-respected Scottish distilleries have installed stainless condensers expressly to capture flavor complementary compounds revealed from a more current study.

Why Bother With Stainless Steel Condensers?

My takeaways from the article are that it appears controlling integral sulphur compounds is more complicated than just removing objectionable aromas (on the hobby level: a copper scrubby in one's riser), and that a stainless condenser can introduce sulphur/meaty compounds regardless if the rest of the still is all-copper or not. I run a copper still and condenser, but have a stainless boiler and will certainly add some copper to it before my next run to see if it makes a difference.
.

[rootbeers]

Well that is their choice in what they chose, I am pointing out a fact written in science, what is better is obviously not what is preferred...

[FL Brewer]

Hey HookLine,

I built a new liebig based on your design, about 46 inches of cooling power. Works very well, uses the about half the water flow of my old condenser, (bigger outer water jacket with no turbulence generator) to knock down the vapor on my stripping runs. Very nice design.

[Bushman]

Hey HookLine,

I built a new liebig based on your design, about 46 inches of cooling power. Works very well, uses the about half the water flow of my old condenser, (bigger outer water jacket with no turbulence generator) to knock down the vapor on my stripping runs. Very nice design.

It’s a good design my first Liebig was built with the wire inside the jacket. HookLine hasn’t been on the forum since 2009 so probably won’t respond.

[drmiller100]

"High efficiency" lab condensers have a thin cooling medium annulus, so I tried a 19 ft 3/8" inside a 1/2" x 0.035" tube for a wort chiller and I chill 6 gal of beer to pitching temp in less than 10 min with about half the water it took with my 1/4" inside 1/2" cooler. Maybe making the outside of a liebig closer to the inside would have a similar effect?

....I have my theories about but I'm no engineer so I'll leave it to another to say why...

Well, I AM a mechancal engineer. And without getting too deep into the physics (mathmatics) of heat exchanger design, there are a few factors which when considered, will improve efficiency of the condenser.

First, heat is transferred OUT of the vapor through conduction through the walls of the heat exchanger’s vapor tube. The heat conduction is proportional to the surface area...that is, the diameter times the tube length. Yet the heat transfer is inversely proportional to the tube thickness. So, you want a thin wall vapor tube...type M instead of type L or type K (typical for copper tubing).

Also, copper is greater than 10 times better at conducting heat than stainless steel, with thickness being equal. But, often stainless tubing has a thinner wall which helps improve its performance.

Now, heat is transferred from the vapor tube(s) into the coolant fluid...typically water. And the heat is collected in the water through convection. Convective heat transfer is optimized by turbulence to a limit. Too fast of water flow will decrease heat transfer, yet water flow slightly greater than laminar flow will transfer heat best. So, slow flow with a narrow annular flow area will be the most efficient...less pumping power input and greater energy transfered.

Successful heat transfer will raise the water exit temperature nearly to the entry temperature of the vapor inlet. This is why counter flow exhangers are preferred...heat transfer efficiency.

But like the heat mixture in the water jacket, the vapor inside the vapor tube transfers its heat via convection to the wall of the vapor tube(s) (exposure to the walls) at which point conduction pulls the heat through the tube wall(s).

If the length of the heat exchanger has limitations geometrically, you can improve performance by using multiple tubes in a tube bank...a shotgun. Again, conductive heat transfer is proportional to the vapor tube diameter by its length multiplied by the number of tubes.

Also, vapor dwell time in the tube bank is increased as the vapor speed is reduced, allowing the vapor to transfer its heat (and condense) more efficiently. Too fast..and the vapor will puff through without fully condensing. And, increasing the water flow rate or adding ice won’t solve the excessive vapor velocity problem...only reducing the heat input to the boiler will help because you’ll reduce the vapor production/mass throughput.

So, vapor speed is a key factor for condenser design as well.

In summary, features to consider are:
1) vapor tube material,
2) vapor tube surface area (diameter x length),
3) vapor flow velocity,
4) coolant fluid (water) flow rate,
5) coolant flow regime (laminar vs turbulent),
6) counter flow design, and finally
7) the number of vapor tubes in the tube bank.

Kinda’ deep answer, but heat exchanger design is a fundamental course for a mechanical engineer. Sorry it seems so complicated...it’s the physics involved. But hey...at least we don’t have to consider radiative heat transfer here.
ss

That is an old post I had not seen before. It is incredibly good. It points out the material used for the condenser is the most important thing and thin copper is probably best from a heat transfer perspective.

I would respectfully ask you to consider the importance of vapor turbulence. The more turbulence the better the transfer.
Likewise the more turbulence in the coolant the less laminar flow the better it works.

[MooseMan]

Ok so I built a long Liebig fairly recently drmiller, and after doing lots of reading, a fair bit of linear thinking and consideration of the principles of heat exchangers, I deduced that the best I could aim at without going mad on materials or designing any fancy turbulators etc, was a long length, with as minimal water jacket thickness as possible.
I went with 28mm over 22mm copper, meaning there is a very, very thin jacket of water that, with the most minimal input flow, has a very quick exchange of fluid up through the jacket.
It's very efficient.
I do have a blade of long, thin, twisted copper in the vapour path to disturb it as soon as it enters the condenser, but it would likely work just as well without it.

[New scott]

I am new here , but if you would read a little on plastic mold injection mold cooling you would get a clearer understanding of the cooling process your dealing with and we found out aluminum wire transfers heat better than brass, bronze or copper in some cooling cavity’s. It took me some years of doing that work to understand it because some of what I thought was backwards and even high temp plastic spirals work great up to about 450 F In the cooling jackets. Also you could use some environmental friendly coolant for CNC machines in a closed loop system to pull heat. I have even seen heat fins on thin wall (.031 thick wall) copper tubing and aluminum cans. Might be worth the read