Will this work to cool my ferm chamber?

[flatulentfox]

Last summer I purchased a large chest freezer on craigs list for 30 dollars. It is very old, and I was aware that it would probably die soon. For $30 it was worth the risk. Well, it no longer works, the temps are rising, and I need a cool place to ferment. The freezer will comfortably hold 6 carboys.

Here is my thought:

I have a perfectly functioning kegerator with a freezer. I want to put a 5 gallon bucket in the freezer full of glycol or saltwater and circulate it through a copper coil (25 or 50 feet?) using an immersible pond pump in the bucket. The coil will be in the now defunct freezer with a fan blowing across it.

All I would need to purchase to make this work is a pump, the rest I have. Will I be able to maintain ale fermenting temps with an average ambient temp of 80 degrees Fahrenheit?

 

[MalFet]

Yep, should work fine.

 

[flatulentfox]

Awesome. That's what I was hoping to hear. Even if it doesn't, I can certainly use the pump elsewhere.

Thanks!

 

[TyTanium]

I like your thinking. +1 to you.

 

[Polboy]

i would make sure your pump will work at freezer tem and in salt/glycol solution also i would think that blowing air through the coil is much less efficient than submerging it in some water, i would try to put big plastic tote in your dead freezer, fill it with water, submerge coil in it and keep buckets/carboys in it

 

[aubiecat]

I think it will work just fine especially since it will be in an inclosed space.

 

[Hang Glider]

I do this in a water bath (as opposed to copper coils circling a freezer) and I had difficulty until I hit the 5-gallon reservoir mark - too much heat in the return glycol, my kegerator wasn't keeping the glycol cold. If I had enough room, I'd do a two-stage - have a 'return tank' (slightly warmer), then pump that one thru loops in cold water into the 'cold' tank.

simple lowe's pond/fountain pump works fine in cold and in glycol for years now, btw.

 

[Huaco]

Instead of a coil, think of using an aftermarket transmission cooler on each end... or at least, use it on the end inside the fermentation chamber. Blow a fan through the fins of the exchanger.

 

[notimepro]

Instead of a coil, think of using an aftermarket transmission cooler on each end... or at least, use it on the end inside the fermentation chamber. Blow a fan through the fins of the exchanger.

I would say this would be your best bet. You can get them pretty cheaply used. Another option would be to use the radiators that computer builders use for liquid cooling loops. Those guys have mastered efficient heat exchange.

There is a good chance your freezer won't be a very good freezer after you do this, though. You are going to be moving a lot of heat from the fermentation chamber.

Either way, 80f shouldn't be difficult to get to.

 

[Hang Glider]

Either way, 80f shouldn't be difficult to get to.

If I read correctly, the ambient 80F is what he's fighting off - trying to cool in the presence of 80F room temp.

FWIW, mine works with the 5 gallons of glycol in a 90F garage, (I'm holding 63F) and my heat exchanger is indeed a transmission oil cooler. I don't recommend used, though - it's likely to be nasty and oily. They're relatively cheap new, on e-bay or at the parts store. However, if it sits in a tub of water instead of air, be sure to get all aluminum. The ones with copper tubing often have steel end caps which will rust.

 

[notimepro]

Good point on the temps.

I have used transmission coolers for PC cooling. Getting the grime out isn't terribly hard if you go used. But I suppose that is one of those cost vs time things.

You will get a more efficient exchange if you get something with flat channels as opposed to round ones as you will have less dead zones.

Another thing to keep in mind is that mixing copper and aluminum in the same loop can be dangerous if it stays in use for long periods of time. Things will start to corrode over time. If I remember correctly, glycol should slow this process, but putting the two together will lead to corrosion eventually.

 

[flatulentfox]

Thanks for the input everyone. I will probably give it a try just with a copper coil, as I already have one sitting here ready to use. I measured my freezer today, and the temp is around 0 degrees F. This makes me think I should probably be leaning towards glycol rather than salt water. Should I come across an old radiator, I will snag it if a plain coil doesn't work to well.


A benefit I hadn't thought of earlier about going this route vs. a chest freezer is that I do not have to worry about compressor cycle time. This should allow me to have a smaller temperature swing...