How much cold can a mini-fridge get with tweaking and mods?

I put a small bath of saline water into the chiller of a mini-fridge at work, and after a few hours it got down to around 18F. Understandably, this is in the coldest part of the fridge, but in theory, with adequate insulation and air circulation, I don't see why the rest of the fridge wouldn't eventually reach this temperature.

I've seen a how-to on instructables.com about modifying a mini-fridge to operate on its back (the door opens vertically), and I think this format would allow the most cold air to remain inside the fridge. How the collar would be modified to allow for a few corny kegs...I don't know yet.

Anywho, those with some experience super-weatherstripping and super-insulating a mini-fridge, how cold can they get and maintain it?

The problem with adding insulation to a mini-fridge is that you would have to add it to the INSIDE. The heat exchanger on most mini-fridges are attached to the outer skin. Adding insulation to the outside would slow down it's ability to get rid of the heat. If you happen to have a model with the coils on the back, then you can safely add insulation to the outside.

Or you can build a custom box and add the innards from a dissected mini-fridge. That's what I did.

I've seen a how-to on instructables.com about modifying a mini-fridge to operate on its back (the door opens vertically), and I think this format would allow the most cold air to remain inside the fridge. How the collar would be modified to allow for a few corny kegs...I don't know yet.

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Can you post a link to this? I'd like to see that for sure. I did not think fridges and freezers could be tipped on their side or back for operation - the compressor relies on oil from a reservoir that will not be available when the unit is not standing straight.

brrman said:

Can you post a link to this? I'd like to see that for sure. I did not think fridges and freezers could be tipped on their side or back for operation - the compressor relies on oil from a reservoir that will not be available when the unit is not standing straight.

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http://www.instructables.com/id/How-to-Convert-a-mini-fridge-to-a-chest-refrigerat/

pjj2ba said:

The problem with adding insulation to a mini-fridge is that you would have to add it to the INSIDE. The heat exchanger on most mini-fridges are attached to the outer skin. Adding insulation to the outside would slow down it's ability to get rid of the heat. If you happen to have a model with the coils on the back, then you can safely add insulation to the outside.

Or you can build a custom box and add the innards from a dissected mini-fridge. That's what I did.

Click to expand...

Part of my idea is to get an old office-water cooler that has a heating component and a mini-fridge component with big coils on the back. How cold does your chamber stay? Do you have any more pics of it?

nebben said:

http://www.instructables.com/id/How-to-Convert-a-mini-fridge-to-a-chest-refrigerat/

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AH - so they DO rotate the compressor! genius!

nebben said:

Part of my idea is to get an old office-water cooler that has a heating component and a mini-fridge component with big coils on the back. How cold does your chamber stay? Do you have any more pics of it?

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mini-fridge-total-dissection-photo-story

It holds and will easily accidently freeze 4 cornies. This is better insulated that it was as a mini-fridge

pjj2ba said:

mini-fridge-total-dissection-photo-story

It holds and will easily accidently freeze 4 cornies. This is better insulated that it was as a mini-fridge

Click to expand...

Yes, but can it get colder than -20 C? Has anyone left it on 100% cycle to see how low you can go?

I don't know. I doubt mine would as it is. I suspect though with enough insulation/sealing it could. Maybe a refridgeration expert will chime in. I don't think the mechanism are different for fridges versus freezers. It's just the size of the system (and the insulation)