DIY glycol chillers and pump ideas?

[rhythmsteve]

I have a bunch of those household chest freezers that were left in a building that i bought, and i was thinking of turning them into chilling units for fermenters. I have 7 bbl plastic conicals that i was going to install 50' copper 1/2" tubing inside of and connect those to a glycol reservoir that would be the inside of the freezer, and either pipe out to this pump.....

http://www.northerntool.com/shop/tools/product_357081_357081?cm_mmc=Google-pla&utm_source=Google_PLA&utm_medium=Lawn%20%2B%20Garden%20%3E%20Sprayers%20%3E%20Sprayer%20Pumps&utm_campaign=Shurflo&utm_content=342811&gclid=CJak_smfi9QCFZiEswoddSEOgQ

OR.... I was going to get a submersible pump and run piping out. As i understand the above mentioned pump should be self-priming so i should be able to keep it outside the freezers and they are fairly cheap. I would hate to go and spend a lot of money on a glycol system, or need a larger cold room, when i have a, damn near, free solution when compared available. Thoughts? Ideas?

[Todd Hicks]

I tried this on a half ass project to chill a vinegar acetator and it did not work at all. There isn't enough surface area contact between cold air and reservoir to really chill the brine water.

Try selling them to homebrewers to use as big kegerators.

[rhythmsteve]

I tried this on a half ass project to chill a vinegar acetator and it did not work at all. There isn't enough surface area contact between cold air and reservoir to really chill the brine water.

Try selling them to homebrewers to use as big kegerators.

That's why i was going to fill the freezer with glycol instead of putting it within another container, so the liquid would be right up against the cooling coils surrounding it.

[feinbera]

What's the actual cooling capacity on the things? I'd worry that, with a volume of just a couple barrels, and a typical use-case of keeping things cold versus getting them cold (who fills their whole chest freezer in one go?), they'd struggle to keep up with seven barrels at high krausen and take forever to cold crash.

If it were me, I'd say forget the homebrewers, and use these to chill kegs for my taproom.

[NS_Nano]

I think it's been discussed elsewhere on the forums, but the biggest issue is that those freezers aren't very powerful in terms of BTUs/hour (which if you open and close them a lot, without a lot of material in there for thermal mass, you'll notice). People seem to settle on immersed air conditioners for that reason when they mickey mouse things. (Search the forum.) There are various online calculators that allow you to figure out how much will be generated per gravity unit, per gallon of actively fermenting wort. You can check to see if your freezer could keep up.

Given that the heat output during fermentation isn't linear, I suppose you could overcome the issue with a large reservoir of glycol, pre-chilled during down times, but given the price of glycol, you're going to hit the point where a proper chilling unit isn't saving you much money pretty fast...

[NS_Nano]

Here's a thread on using an immersed air conditioner. Not endorsing the idea, but many of the issues relevant to your question are discussed. http://discussions.probrewer.com/arc...p/t-23413.html

[rhythmsteve]

Ok. So the consensus seems to be "NO" on a glycol chiller, but another thought came to me.....how about lining it with copper tubing inside the freezer, build a collar, and use it as a second stage glycol, or cold water heat exchanger?

[rdcpro]

Ok. So the consensus seems to be "NO" on a glycol chiller, but another thought came to me.....how about lining it with copper tubing inside the freezer, build a collar, and use it as a second stage glycol, or cold water heat exchanger?

As NS_Nano and Feinbara say, chest freezers have very low BTU/hr heating capacity...yours are probably somewhere around 500 to 1500 BTU/hr. Compare that to a typical air conditioner of between 8000 and 12,000 BTU/hr. Improving the heat transfer doesn't change the capacity. Even if you got your heat transfer 100% efficient, there's simply not very much heat to transfer. Try one out: see if you can chill a couple barrels of water more than a few degrees. For example, fill one with water (but it has to be full enough to cover the cooling coils near the top of the freezer). If you can chill water down to say, 40F, maybe you could use this as a sort of CLT or second stage for knockout. But I'm doubtful.

Regards,
Mike Sharp