Glycol Chiller Build - Gylcol vs Ethanol

[Surly_goat]

Here's my glycol build. Not finalized but wanted to cold crash the fermenter so figured I'd test it out.



STC 2000 controls the AC unit. Wiring is the compressor hot and low fan wire connected to input hot with a paper clip and neutral input to start capacitor with paper clip. Everything to finalized with proper connections in a box.

The liquid is currently RV Ethanol anti freeze but I've got some propalene glycol on the way from Amazon.

Can anyone tell me why my anti freeze is sitting at -10c and I cant get the fermenter below 0.6 or 0.7? I'm assuming it's just heat transfer through conical walls. Does glycol and water transfer heat better than ethanol?

 

[Pappers_]

Can't help with your question, but that looks nice - well done!

 

[tofuguy]

Maybe a dumb question, how long was the ethanol at -10? Second, maybe the stagnation inside the fermenter is causing the large delta. Also the outside temperature will have an affect on the final temperature of the fermenter. The chiller has to fight that heat source constantly versus a refrigerator where the ambient will match the fermented beer. All guesses... Great start to a build!

 

[Surly_goat]

I had it at -12 to -10 for a while, to the point where it was slushing on the rad. Eventually I adjusted the temperature up to -10 to keep it more fluid.

It wasn't flowing as well when super cold.

 

[mongoose33]

Can anyone tell me why my anti freeze is sitting at -10c and I cant get the fermenter below 0.6 or 0.7? I'm assuming it's just heat transfer through conical walls. Does glycol and water transfer heat better than ethanol?

What's the ambient temp?

Anything sticking out from the neoprene sleeve is a radiator, in this case sucking heat in from the surrounding environment. So that's one source. Another is the speed at which the pump circulates the liquid. Slow is...well, slow.

Another is whether your return line is essentially feeding the supply line without mixing well with the fluid in the reservoir. I've been working on a somewhat similar build using my Spike fermenter and their temp control kit. The supply and return lines are right next to each other unless you separate the neoprene insulation around them.

Here's a pic showing how far apart mine are:



A fourth possibility is freezing in the lines which would slow the volume of flow. Mine has a Propylene Glycol/water mix; I actually froze it to a slush when I was crashing a keg in the fridge part of that appliance.

I've been working on ways to isolate the fermenter from ambient; so far, the best solution has been to take a mover's blanket and wrap it around the fermenter, securing it with spring clamps. Something similar will help your situation a lot.