Glycol Chiller Build

[idylldon]

I had a few hours to spare yesterday so I put one of the window AC unit glycol chillers together to use with my 1/2 bbl. fermenter. It will be nice to be able to ferment lagers during the summer and hold the temp within a degree. I'm waiting for my thermostat for the fermenter but it's ready to go once that arrives.















I'll be using my 1/2 bbl. system as a pilot system for the new brewery I'll be brew master at. With any luck, we should be open by the end of the year.

Cheers,
--
Don

 

[RocketBrewer]

That looks pretty cool! Anxious to hear how it works out. Is your fermenter jacketed or are you cooling a chamber with it?

 

[idylldon]

That looks pretty cool! Anxious to hear how it works out. Is your fermenter jacketed or are you cooling a chamber with it?

My fermenter is jacketed. I'm going to use quick disconnects, though, so I can also use it to drop my wort the final 10 degrees or so when I do lagers.

Cheers,
--
Don

 

[bemerritt]

What fluid are you using in the chiller?

 

[idylldon]

What fluid are you using in the chiller?

Propylene glycol/water mix. It's Sierra brand so it's not the usual red/pinkish color. It's what I had on hand to give it a test.

Cheers,
--
Don

 

[day_trippr]

There's a hint at the top of the thread...

Cheers!

 

[idylldon]

Anxious to hear how it works out.

Got the Ranco thermostat yesterday and finished wiring it up. Temps during the day are in the low 90s and this thing doesn't even break a sweat keeping my fermenting beer at 68F. I set the Ranco to have a 1 degree differential and the thermostat controlling the glycol temperature to 25F with a 6 degree differential. The AC unit hardly runs since the glycol holds temp really well in the insulated cooler.

When the pump kicks on to circulate the glycol to the fermenter jacket, it usually takes less than five minutes to drop 17 gallons of fermenting beer back to the set temp. The AC unit kicks on towards the end of this period and runs for maybe 10 minutes to drop the glycol back to 25F.

In a word, it's amazing. While I have had glycol chillers hooked to this fermenter in the past, they were not even close to having the capacity this one has.

Worth every damn dime.

Cheers,
--
Don

 

[bemerritt]

Propylene glycol/water mix. It's Sierra brand so it's not the usual red/pinkish color. It's what I had on hand to give it a test.

Cheers,
--
Don

worried about it not being food grade? I have been running my chiller (similar setup with just water and am ready to add glycol but i don't feel like springing for the food grade variety. Any chance you have a link?

There's a hint at the top of the thread...

Cheers!

Not sure how serious you were with this, but glycol doesn't nearly tell the whole story. Food grade? Mix? Much more to the story that I was interested in.

 

[idylldon]

worried about it not being food grade?

No. If I were running a commercial establishment, sure, but not in my home setup. It's safe for consumption so I'll leave it at that. I don't think any of it would be good for anyone to drink in any quantity whether it's "food grade" or not. In my system, the chance of it entering the beer is nonexistent.

Any chance you have a link?

I bought it a long time ago and it's been sitting on the shelf in my garage, but I think I purchased it at an RV supply store. At this point, my guess is it won't be much cheaper than the food grade stuff.

My mixture isn't that strong; that is, it's more water than glycol. I wanted it thinner because it transfers temperature better when it's more diluted and I don't plan to run my chiller lower than 25F anyway. It's also easier on the circulation pump.

Cheers,
--
Don

 

[bemerritt]

Just like you I run it through a jacketed conical, so I agree, very low risk. I guess I'm off to find some. Thanks for the insight.

 

[Woodbrews]

Great setup! Very clean looking, too. What kind of jacketed conical is that?

 

[Spellman]

Very nice looking build! How many btu's is that ac?

 

[idylldon]

Great setup! Very clean looking, too. What kind of jacketed conical is that?

It's one I bought used back in '94 for $200. It didn't have a name on it. Holds about 22 gallons. I built the stand to get it up higher and then added the glycol jacket. It's been bulletproof from day one. I was big on controlling fermentation temperatures early on in my brewing career.

Very nice looking build! How many btu's is that ac?

5000 and it hardly ever runs, even when I have a lager in the fermenter and it's 90 degrees outside. I should have built one of these years ago because the one I used to use with this fermenter struggled to keep up.

I highly recommend one of these. I think I have $300 in it.

Cheers,
--
Don

 

[LovesIPA]

Don,

This is impressive. I would be very interesting in building one of these. I really have no idea how your system works though. I understand that glycol is chilled to 25F but are you using the AC unit to do that? How do you plumb them together? Do you have to use a Rancho controller or would an STC-2000 work? Is there a pump? Where did you source this stuff?

Thank you! This might be my next homebrew project.

 

[idylldon]

Don,

This is impressive. I would be very interesting in building one of these. I really have no idea how your system works though. I understand that glycol is chilled to 25F but are you using the AC unit to do that?

Yes. Here's a picture of the evaporator part of the AC unit (the part that gets cold when the AC kicks on) submerged in the glycol bath:



This will give you an idea of how the evaporator needs to be manipulated into position:



The hardest part of the build is CAREFULLY bending the copper tubing connected to the evaporator so it can hand down in the cooler. Luckily, the AC unit I bought had more than enough length of copper tubing to facilitate this. Once that was done, the rest was pretty straightforward.

How do you plumb them together?

The chilling unit is connected to the jacket on the fermenter via vinyl tubing and quick disconnects.

Do you have to use a Rancho controller or would an STC-2000 work?

I'm not familiar with either of those since I used Johnson controllers, one is used to set the glycol temperature and one is used to control the pump feeding the jacket on the fermenter.

Is there a pump?

There are two pumps, one circulates the glycol around the evaporator with the AC kicks on and one circulates the glycol to the jacket on the fermenter when the temp of the fermenting beer rises 1 degree over the set point. So, if I've got the fermenter set to 68 the glycol circulation pump will turn on when the temperature of the beer gets to 69.

Where did you source this stuff?

I bought the 5000BTW AC unit and the Igloo cooler at Walmart. I think the AC unit was just over $100 and the cooler was around $30. I already had the two thermostats and submersible pumps from my previous glycol chiller so I didn't purchase those recently. They are readily available from the usual suspects, your LHBS, Grainger, etc. The main submersible pump, the one that supplies the jacket, usually is used for a waterfall or some other water feature in a pond setting; the smaller submersible pump that circulates the glycol around the evaporator is for an aquarium. They both work perfectly for this application.

There are quite a few detailed threads on building something like this. I just saw one and decided to build one for myself. Now that window AC units are so inexpensive, it makes a lot of sense to go with a setup like this. I've been brewing since '89 and learned right from the start that controlling fermentation temperature is one of the most important things to ensure great beer every time!

BTW, when you buy an AC unit, get one with manual controls. They are cheaper and easier to wire up for this application.

Cheers,
--
Don

 

[SleepyCreekBrews]

I run one of these based on a dehumidifier , and I've found I save money by only triggering off the fermenter temp, as opposed to controlling both glycol temp and fermenter temp.
...food for thought

 

[helterscelter]

I run one of these based on a dehumidifier , and I've found I save money by only triggering off the fermenter temp, as opposed to controlling both glycol temp and fermenter temp.
...food for thought

sorry to resurrect an old thread, but can you elaborate some on the difference you saw in controlling fermenter temp only vs both fermenter and glycol bath? how does your system control the compressor to chill the bath in response to fermentor temperature rise?

 

[SleepyCreekBrews]

sorry to resurrect an old thread, but can you elaborate some on the difference you saw in controlling fermenter temp only vs both fermenter and glycol bath? how does your system control the compressor to chill the bath in response to fermentor temperature rise?

Basically, when I first started using it, I was using 2 temp controllers. The first temp controller was monitoring the glycol solution and keeping it at 9c all the time. The second controller was monitoring the fermenter temp and triggering the glycol pump (that pumps through the immersion coil) to chill the beer. Sort of a wasted effort as the beer temp doesn't rise fast enough to warrant the near-instant chilling strategy.

Now I just use 1 controller with the thermocouple on the fermenter and turn on both the chiller and the circulation pump at the same time.

 

[helterscelter]

Basically, when I first started using it, I was using 2 temp controllers. The first temp controller was monitoring the glycol solution and keeping it at 9c all the time. The second controller was monitoring the fermenter temp and triggering the glycol pump (that pumps through the immersion coil) to chill the beer. Sort of a wasted effort as the beer temp doesn't rise fast enough to warrant the near-instant chilling strategy.

Now I just use 1 controller with the thermocouple on the fermenter and turn on both the chiller and the circulation pump at the same time.

Interesting. That would be somewhat difficult to do if you have more than one fermenter in your loop. Not horrible, but you would need some logic or wiring to manage a logical or state of the compressor.

Do you have any info on how much cost efficiency you gained by doing it this way? I know swmbo would be more pleased with a cost effective setup.

 

[RonPaul]

Basically, when I first started using it, I was using 2 temp controllers. The first temp controller was monitoring the glycol solution and keeping it at 9c all the time. The second controller was monitoring the fermenter temp and triggering the glycol pump (that pumps through the immersion coil) to chill the beer. Sort of a wasted effort as the beer temp doesn't rise fast enough to warrant the near-instant chilling strategy.

Now I just use 1 controller with the thermocouple on the fermenter and turn on both the chiller and the circulation pump at the same time.

I'm interested in this approach... I like the idea because it requires just 1 temperature probe and would seem to save some energy.

However, my concern is that the glycol chiller could end up running for a long time if the fermenter temp doesn't follow closely behind... and that would end up chilling the glycol too much.

What are the cons to this approach?

 

[SleepyCreekBrews]

I'm interested in this approach... I like the idea because it requires just 1 temperature probe and would seem to save some energy.

However, my concern is that the glycol chiller could end up running for a long time if the fermenter temp doesn't follow closely behind... and that would end up chilling the glycol too much.

What are the cons to this approach?

I don't use that system anymore, but the drawback you mentioned was the only one I could think of (other than the minor delay in chilling as the refrigeration gets the glycol down to temp) .
It worked well, but was messy since everything sweated in the summer and I was constantly having to mop up water. I use an air conditioned chamber now.

 

[Spellman]

I think you will have way less headaches running it with 2 temp controllers. On mine I have 1 temp controller for the glycol, then 4 temp controllers to do 4 separate fermentations that are triggering individual pumps for the lines. I insulated the glycol lines on mine and have very little condensation. I built out a similar unit for a friend and he doesn't have his line insulated and says it makes a hell of a mess. A few dollars worth of pipe insulation from a home improvement store is all it takes.

 

[RonPaul]

I ended up with a separate temp controller for the glycol for an additional reason: in case a pump fails or the conical isn't cooling beyond a certain point, I don't want the a/c unit running non-stop, forever. I then use 2 more temp probes; one in each of the conicals with a separate pump going to each of those. In order to save $ by not keeping the glycol cooler than needed, I have different stages that I'll run the glycol at. I keep it relatively warm (~45F) if I'm just fermenting some ales, but will change to ~25F if I want to cold crash. Since the pumps for the conicals are separate, the temp of the glycol doesn't matter as long as it's ~20F colder than both of the conicals.

One other thing I'll mention for critique (and to help anyone else looking for ideas), is that I run an additional pump to circulate the glycol, but that only runs when the a/c unit is on (glycol is chilling). My logic is that the glycol will also get circulated when either of the other pumps for the conicals are running and that should be good enough.

 

[jjanes123]

I realize this in an old post but...

How did you wire the unit? I see two controllers, One (Ranco?) for the AC unit and 1 to control the temp of the fermenter.

I am looking to build one of these ASAP. I am planning to use a single controller to power on the pump and the AC unit.

I was going to place the temp probe for the AC unit in a warm spot on the unit to keep the AC on all the time.

Thoughts? How did you wire yours?

Thank you

 

[Spellman]

You will need 2 controllers. If you run the ac unit all the time it will freeze up on the coil and destroy the unit (might get half a day to a day out of it before it is ruined). I power mine with a stc-1000, but you will have to make sure the ac unit doesn't draw too much power to be controlled that way.

 

[mattyj904]

What do you do to address the compressor dripping? I'm thinking about doing this with my fermenters inside the house and don't want to have to worry about the condensation build up. Currently I have the ftss for my brew bucket with water in a lil brown keg in my keezer for chill water. I just ordered another ftss for my other brew bucket and may upsize soon so now I'm looking at good solution that is efficient, low maint, and allows for expansion.