Idea for a glycol chiller using mini fridge

[SanPancho]

so long story short, helping some buddies in mexico rig up a glycol chiller. the typical DIY AC unit build is a bit worrisome, as i get conflicting info on how cold they can get. we need the 25-28F range. have been told that's dependent on the refrigerant used. no idea if thats true. not sure i want to spend my time shopping for ac units in baja.

but i know your old school /old style dorm fridge- the one with the little freezer compartment in the top corner- they get plenty cold to put us in the 25F range. i vaguely recall that the cooling coils were exposed in some units, or am i wrong?

if so, the idea would be to bend the coils and drop them down into a reservoir holding the glycol.

does anybody know how easy it is to disassemble those guys? is there enough length on the copper lines to bend that sucker from the top of the fridge down to the shelf where it'd sit in the glycol bath? like so

anybody else done this? i got the idea from somebody who took a dorm fridge and rearranged the compressor mounting so they could lay the fridge on its back- basically turn it into a chest fridge as opposed to upright fridge. might even be able to skip the reservoir and just fill the thing with glycol.

 

[beermanpete]

I did this with marginal results. The evaporator in mine is aluminum. I was able to remove the mounting screws and bend it down so about half of it is in a bucket of water. I used a submersible pump to circulate the water through a S.S. coil in an ice chest that held my fermenter. The best it did was hold in the mid-60s during the fall in So. Cal. Better immersion of the evaporator would help but I gave up and bought a chest freezer.

 

[SanPancho]

you think this was attributable to the lack of cooling power from the fridge? i'm just starting to look, but the little info ive been able to find actually has pretty low btu numbers for dorm fridges. This might not be the great idea i thought it was.

 

[beermanpete]

The cooling power of the fridge is certainly part of it. Better insulation of the fermenter would help. I insulated the lines but had the fermenter in a ice chest and could not close the lid so placed towels over the top. Ultimately, a fridge that is large enough to place the fermenter into it would be better. A lot of people use the dorm fridges and build out the front to make room for the fermenter.

 

[SanPancho]

Right, but in this case our heat transfer should be much more efficient as our transfer medium is liquid and not air.


Ultimately the btu is what matters here, and im not seeing alot of positive info in regards to that. Seems pretty hard to find thatinfo.

 

[Metzen]

so long story short, helping some buddies in mexico rig up a glycol chiller. the typical DIY AC unit build is a bit worrisome, as i get conflicting info on how cold they can get. we need the 25-28F range. have been told that's dependent on the refrigerant used. no idea if thats true. not sure i want to spend my time shopping for ac units in baja.

but i know your old school /old style dorm fridge- the one with the little freezer compartment in the top corner- they get plenty cold to put us in the 25F range. i vaguely recall that the cooling coils were exposed in some units, or am i wrong?

if so, the idea would be to bend the coils and drop them down into a reservoir holding the glycol.

does anybody know how easy it is to disassemble those guys? is there enough length on the copper lines to bend that sucker from the top of the fridge down to the shelf where it'd sit in the glycol bath? like so


View attachment 576858

anybody else done this? i got the idea from somebody who took a dorm fridge and rearranged the compressor mounting so they could lay the fridge on its back- basically turn it into a chest fridge as opposed to upright fridge. might even be able to skip the reservoir and just fill the thing with glycol.

You can do it for smaller batch sizes. I’ve been able to cold crash one 5 gallon batch at a time down to high 30s F. I documented my build at the link below. Its exactly what you are describing. A few others have also done it and shared their findings in the thread.

https://www.homebrewtalk.com/forum/threads/metzens-mini-fridge-glycol-chiller-conversion.631203/