Tell me why I'm an idiot. (glycol chiller edition)

So most of my projects begin with redneck version of "I dunno why you need that fancy thing when there is a duct tape to be had..." sort of thinking.

I've recently got hold of a double tap tower and I want to mount it in my kitchen running from the beer fridge in the garage.

Below is my train of thought, if you could point out holes in my thinking, I'd appreciate it.

The distance is right around 30 feet, but let's say 35 to be safe.

If we use the Length = (KegPressure - (Height*.5) - DeliveryPressure)/LineResistance formula...

We could increase the line to about 45 feet, use 5/16" line, and set keg pressure to 10 psi.

If we kept the fridge at 40 degrees, that be around 2.3 volumes. Not perfect, but it's a starting point.

To keep it cool, I'd like to put an aquarium pump in five gallons of the non-poisonous antifreeze sitting in the fridge. Then have a length of line sending and returning the cold prop-glycol wrapped together with my beer lines. That braid would then be wrapped in insulation.

Is this never going to work? Do I have to spend large amounts of cash on a glycol chiller?

From what I've read in other posts, that'd work just fine. I have no experience with it, but I can swear I've seen this exact scenario, maybe with 1/4 line though, and this huge insulated trunk line running across this guys house.

As long as it's a straight run you should be OK. If there's an increase in elevation the pump may not have the balls to push the glycol that far.

What's the skinny with glycol? Am I correct in thinking that the red nonpoisonous anti freeze is what I'm looking for? I don't have to buy that $20 a gallon food grade stuff right?

If I use the 1/4" line, which was my original design, I need 27 psi to push the beer to the tap. That would be way too carbed so I'm wagering on this 5/16" business.

why not just buy the food grade stuff anyways... couple extra bucks in the setup is allot cheaper then medical bills.

Yes - you need the food grade stuff - Propylene Glycol. You don't want to be handling Ethylene Glycol - very toxic stuff.

Look into the bev seal ultra 1/4" line, its thinner but much more rigid than regular beer line and has much less restriction than regular beer line. You could probably do 40' with that line and still serve at 12 psi. I would just get that " pet safe" atifreeze from the autoparts store. If you can afford it run the glycol thru copper pipe with the beer lines wrapped around it. I'm sure it would keep it much cooler than if the glycol was in a plastic tube.

I don't think the fridge would be able to keep the coolant cool enough, particularly with that long of a run. I tried something similar with only 20' and it just didn't work out. If you decide to try it, I don't think you need antifreeze if you are aiming for 40 degrees.

Yes - you need the food grade stuff - Propylene Glycol. You don't want to be handling Ethylene Glycol - very toxic stuff.

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I was definitely going to use propylene, but there are multiple grades. I think they actually put the food grade stuff in your drinks. It's $20 bucks a gallon vs $6 for the other stuff.

Look into the bev seal ultra 1/4" line, its thinner but much more rigid than regular beer line and has much less restriction than regular beer line. You could probably do 40' with that line and still serve at 12 psi.

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Awesome, thanks for that. I'd like to use 1/4", but I'm not sure about all the resistance ratings that people throw out there. I don't have the dough right now for copper lines or I'm sure that would be pretty awesome for chilling.

I don't think the fridge would be able to keep the coolant cool enough, particularly with that long of a run. I tried something similar with only 20' and it just didn't work out. If you decide to try it, I don't think you need antifreeze if you are aiming for 40 degrees.

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I was going to use propylene-glycol for its heat exchange properties, not because I thought it would freeze.

Ok - did not know that. Still, I would use food-grade stuff. You're not changing it that often and it's a safety factor on the rare instance someone freaky happens.

I would think 1/4" is 1/4". I'm not sure why any one would be better than another. Thinner seems to be more prone to add resistance than reduce it. Not sure I see the math here.

I use the 1/4" bev seal ultra and love it. For your calculations, use .4PSI restriction per foot based on what I heard from the factory. If you are just looking for line to handle the coolant, you can use regular polyethylene tubing. That's the same material as the bev seal ultra but without the PET liner for beer contact.

I may be wrong, but my understanding was that water had better heat transfer than glycol, so I'm not sure if it helps. See what you can find though. I'd be interested to hear how it works out.

I use it too - but I don't understand how 1/4" ID in one hose versus another makes any difference - it's still the same opening size. Maybe I'm missing something?

Glycol does help transfer heat better than water. However - it will also warm up the bath quicker too. It needs to be a big bath. People I know that have done this use small chest freezers and pour the liquid right into them.

The difference in the tubing is that the bev seal ultra has a smoother coating of PET inside. Basically there is less friction against the walls, so it gives less resistance

manoaction said:

I was definitely going to use propylene, but there are multiple grades. I think they actually put the food grade stuff in your drinks. It's $20 bucks a gallon vs $6 for the other stuff.



Awesome, thanks for that. I'd like to use 1/4", but I'm not sure about all the resistance ratings that people throw out there. I don't have the dough right now for copper lines or I'm sure that would be pretty awesome for chilling.



I was going to use propylene-glycol for its heat exchange properties, not because I thought it would freeze.

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As long as it is propylene your good. Food grade just means there are no additives. The other grade is technical grade and it may have additives in it depending on what it is for. I think you would be fine either way and you do not need much as you only need a percentage of it in solution for this process. If you could have it in a freezer, it would get colder, which would be benificial in the size of your run. Perhaps adding a blower and cooled line? Make sure to look at the head PSI rating for the pump you use too. Good luckand can not wait to see how it turns out. Also you dont have to use copper ya can just use anything that is conductive really so other cheaper metals could be a start.

manoaction said:

Is this never going to work? Do I have to spend large amounts of cash on a glycol chiller?

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its exactly what i did, except for the expensive glycol chiller part. i used an air conditioner and some fiberglass instead. i use the $4/gallon bright pink RV water line antifreeze. its not food grade, but its P.glycol which is good enough.

Glycol does help transfer heat better than water.

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no it doesnt

I was going to use propylene-glycol for its heat exchange properties, not because I thought it would freeze.

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regular water has better heat exchange properties. there is actually no better liquid, besides some liquid metals, that has more favorable properties than water. the only reason to use anti-freeze is due to its anti-freeze properties (which you will need; i usually keep my glycol circulating at 26 or so degrees) or sometimes to modify the boiling point or for anti-corrosive additives.

audger said:

regular water has better heat exchange properties. there is actually no better liquid, besides some liquid metals, that has more favorable properties than water. the only reason to use anti-freeze is due to its anti-freeze properties

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This is correct.

audger said:

regular water has better heat exchange properties. there is actually no better liquid, besides some liquid metals, that has more favorable properties than water. the only reason to use anti-freeze is due to its anti-freeze properties (which you will need; i usually keep my glycol circulating at 26 or so degrees) or sometimes to modify the boiling point or for anti-corrosive additives.

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But a glycol mix to reduce the freezing point and thereby allow an increased temperature delta makes up for the inefficiency of the solution heat exchange, right? I'm planning a DIY AC central chiller plant and was wondering if straight water at ~38 would be more user friendly. Thinking a common reservoir with loops to heat exchangers for serving, lagering, and ferm control.

jcaudill said:

I use it too - but I don't understand how 1/4" ID in one hose versus another makes any difference - it's still the same opening size. Maybe I'm missing something?

Glycol does help transfer heat better than water. However - it will also warm up the bath quicker too. It needs to be a big bath. People I know that have done this use small chest freezers and pour the liquid right into them.

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This part of the discussion is regarding the thickness of the line. Bev Seal is thinner walled than regular beer line.

starman said:

But a glycol mix to reduce the freezing point and thereby allow an increased temperature delta makes up for the inefficiency of the solution heat exchange, right? I'm planning a DIY AC central chiller plant and was wondering if straight water at ~38 would be more user friendly. Thinking a common reservoir with loops to heat exchangers for serving, lagering, and ferm control.

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the increased delta makes up for the inefficiency, yes. but that doesnt mean that glycol is more efficient than water; just that its making up for it in other ways (by being colder). water is much more efficient than air at conducting heat, but if i had -500 degree air, vs +40 degree water, the air would chill the beer faster.

if you take 1 gallon of glycol and 1 gallon of water, both at 40 degrees, and drop a 70 degree can of beer in each of them; the beer in the water will both chill faster and reach a (marginally, but measurably) lower final temperature than the beer in the glycol.

remember you will always have a considerable delta between the coolant tempearature, and the actual beer or refrigerator temperature. usually its 4-10 degrees depending on your insulation and other things. so if you want 38 degree coolant, you will be drinking beer up near 45-50 degrees. normally glycol loops are run 24-28 degrees, and the beer is kept at 35-38. the larger temp delta means you dont have to constantly circulate it. if your target temp is 38 degrees, and your coolant is 36 or 37, you will have to circulate coolant 24/7 to keep that temp.

jcaudill said:

I would think 1/4" is 1/4". I'm not sure why any one would be better than another. Thinner seems to be more prone to add resistance than reduce it. Not sure I see the math here.

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The Accuflex stuff is glass lined. This makes it impermeable to leaching and also reduces the resistance. 3/8 has a negligible difference in resistance over normal Bev-Lex, but 1/4 is 2 or so to 1 and 5/16 is nearly 3 to 1 I think. I'll look those numbers up later maybe... But emailing the company would probably be the best way to go.

heckels said:

As long as it's a straight run you should be OK. If there's an increase in elevation the pump may not have the balls to push the glycol that far.

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If you prime the line before elevating it and keep the pump inlet and the return outlet fully submerged you will basically negate any head pressure by creating a balanced loop. Think siphon.

ChandlerBang said:

The Accuflex stuff is glass lined.

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"Glas-Flex" or whatever their name for it is just a brand name. the lining is made out of PET plastic. no actual glass is used (imagine the lawsuits if it craked and someone drank a pint full of glass shards...).

audger said:

"Glas-Flex" or whatever their name for it is just a brand name. the lining is made out of PET plastic. no actual glass is used (imagine the lawsuits if it craked and someone drank a pint full of glass shards...).

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Berrier tubing is the term that escaped me. You're right, it's not glass like window glass... think fiber optic cables. PET plastic is a whole different deal.