Glycol Chiller for Wort

[Run4BeerCO]

I'm currently building a glycol chiller from an 8000BTU AC that I'll use to control two 14gallon Chronicals.

My brewing location in the garage is currently far away from a water source I was thinking of adding additional ports to my glycol chiller so that I could hook up my therminator on brew days and use the glycol to chill the wort. Since I'll have 5 gallons of glycol at the most I'll need an additional solution.

1. I run the glycol through the therminator and then run the glycol through an immersion coil in an ice bath before returning to the reservoir

2. I run the wort through an immersion coil ice bath and then through the glycol cooled therminator. (Probably better than Option 1 because of delta T, but I'm no engineer)

3. Some sort of secondary glycol resorvior prechilled before brew day.... (I have my two orange igloo coolers from my early homebrew days I could repurpose)

4....

 

[Dland]

Or you could partially chill w immersion coil w water and or water/ice bath, then finish chilling to pitching temp w glycol chiller once wort is in fermentor. An 8,000 BTU chiller should be able to handle that pretty well, if you get it down below 100F before transfer.

Of course, I don't know your local temperature conditions, so maybe that is not enough.

 

[Vale71]

Running the glycol through the ice bath first makes no sense as the glycol should already be colder than the ice bath so you'd actually be warming it up. You definitely need to run the glycol through the ice bath after it has run through the CFC to chill it down again to an acceptable temperature for the chiller to keep on working.

8000 BTU would theoretically chill 1 kilogram of water by 80°C (from 100°C to 20°C) in about 2.5 minutes. 5 gallons is about 20 times that so it should take you about 50 minutes to chill down to pitching temp. This is however assuming zero losses which will never be the case but on the other hand you have the contribution of the ice bath which we can't estimate without any data on the immersion chiller so it might take longer or not also depending on actual losses.

A large pre-chilled glycol reservoir would give you much shorter times provided it is large enough and you never run the water back to the same reservoir which would increase its temperature and reduce the CFC's efficiency. This means you would need two equal sized reservoirs, one full of pre-chilled glycol and one empty to transfer the warm glycol to for future reuse (assuming dumping it every time would be too expensive).

 

[Run4BeerCO]

I wasn't going to run glycol through the chiller. My original idea was to run the warmed glycol through the immersion chiller before returning to the reservoir to minimize the reduction in efficiency. My second idea was to run the wort through the immersion chiller first and then through the glycol cooled therminator.

New thought... I run a coil through my coolers lid that I then use as a CLT filled with glycol. I could transfer to the second spare cooler and simply swap the lids and repeat

 

[Vale71]

My original idea was to run the warmed glycol through the immersion chiller before returning to the reservoir to minimize the reduction in efficiency.

That would be the best option. Pre-chilling the wort to an intermediate temperature would only reduce the CFC's performance and you could run into issues with the AC unit if the glycol in the reservoir gets too warm.

 

[Bobby_M]

Breweries use a cold liquor tank for this. If you use any of your 5 gallon coolant, it will be out of commission for cooling any active fermenters so I really wouldn't want to do that. I would use a two tank system (two 15 gallon barrels). Mount a glycol coil in the lid of one and get that water down to 33F the night before brew day. During chilling, pump that tank through your chiller and collect the warm glycol in the empty tank.

If you're doing a 15g batch, the resulting temp in the fermenter will be (212-33)/2 = 90F give or take. Since you have a glycol controlled CF, you really don't need the wort to be crashed all the way down to pitching temps. Just set the controls to take the wort the rest of the way down in the CF from there. If you really want to reach pitching temps in one pass, you'll need to up the size of the cold water tanks. You certainly don't want the glycol chiller to have to try to recover real time.

Now let the water in the catch tank naturally cool down and when you need to brew again, drop the cooling coil lid onto that one.

 

[Run4BeerCO]

I think that's my plan with my old homebrew coolers. I'm going to install a coil through the interchangeable lid. I'll cool that the night before brew day and use that glycol to chill my wort before letting the fermenter cool the rest of the way without taxing the glycol chiller too much.

I plan to mostly brew 5 and 10 gallon batches.

 

[Bobby_M]

I'm sure that will be effective. If you plan to reuse that liquid over and over, I would think about adding something to help keep bacterial growth down, maybe a capful of a bleach every once in a while.

 

[Run4BeerCO]

I was planning to use glycol. Perhaps just at a lower concentration than the 2:1 Water/Glycol in the actual chiller. I see that at a 20% concentration the glycol would inhibit growth. Is there any reason I shouldn't use glycol in this set up?

 

[Bobby_M]

Glycol has less heat capacity than plain water. The only reason you would be forced to use it is if the ambient temps in that shed ever get below freezing.

 

[Vale71]

I was planning to use glycol. Perhaps just at a lower concentration than the 2:1 Water/Glycol in the actual chiller. I see that at a 20% concentration the glycol would inhibit growth. Is there any reason I shouldn't use glycol in this set up?

There are bacteria that can actually feed on glycol and will foul the coolant if it's left at ambient temp for an extended period of time. Ask me how I know...

 

[Run4BeerCO]

There are bacteria that can actually feed on glycol and will foul the coolant if it's left at ambient temp for an extended period of time. Ask me how I know...

Ugh thanks for the insight! I had no idea, but definitely would have learned next summer. I owe you a beer.