Largest area a dorm fridge will chill?

[Ed_]

Hi all,

I'm about to start work on a fermentation chamber using an old dorm fridge to cool it. However I'm not sure how large I can make the cabinet without over taxing the refrigerator. Right now I was looking at around a 16 cubic foot area anyone have any idea if this is too much or not?

 

[mnadamn]

first we need to know the power of the fridge. There should be a btu rating somewhere on the compressor or pump. Also, we need to know the insulation you are using and it's r value.

 

[david_42]

I suspect it's too much by a factor of 3-4. I wouldn't try for more than twice the original cubes, unless you are willing to keep the temperature around 50F.

 

[HillbillyDeluxe]

Dude, the electric bill alone would pay for you a nice conditioning fridgein about a year

 

[Ed_]

Checked the compressor and unfortunately it doesn't list the BTU rating. I also tried searching on the manufacture's site for some info but apparently the thing is too old.

Guess this means I will be seriously scaling back the project. I'll probably just do it large enough for a single 5 gallon bucket at this point.

Thanks for the info.

 

[rudy0498]

I built a kegerator into my bar with the same concept. Here's the thread I started when I was asking questions and shows my results: Cold Box Project

I had what I believe is a 4.5 CF fridge, and the total CF I chilled ended up being about 12 CF. One difference from my original plan was that I ended up going with R12 rated foam board. It worked so well that I was able to get it well below freezing. It didn't seem to be too hard on the compressor, but the compressor is REALLY quiet so I'm not 100% sure how often the compressor was cycling.

One idea to note. As mmb mentioned in my thread, liquids have a higher thermal density than air (not sure if that's the right terminology or not). This means that it is easier for them to hold temperature, but harder to get them to that temperature you want to hold. One thing I plan to do is get my kegs down to temp using a spare fridge in my garage, so the mini-fridge will not have to do it. I will keep as much of the spare/unused air space as possible occupied by liquids that are already cold or cooled (spare water jugs, whatever) to ease the workload of the compressor. Make sense?

Worst case scenario your old fridge will crap out and you'll have to get a more heavy duty one. In my case it was a free fridge a family member gave me, so it was still the cheapest option available to me even if it didn't work out.

So I say go for it!

 

[Cpt_Kirks]

Those little fridges have compressors rated at about 400 BTU, more or less.

I have heard the same size compressors are used in fridges up to about 4cf.

 

[rudy0498]

+1 to my earlier post....If you:
-strive to keep the open air space less than (or around) what the CF of the mini fridge is
-you get your fermenters down to temp through another method
-and aren't constantly opening the cabinet door
-achieve a comparable R rating to the fridge itself

then, you really won't be working the compressor THAT much harder than it would be if you were cooling the empty fridge itself. And if you are holding temps in the 60s for ales, you definitely won't be working the compressor that hard. Lagering temps shouldn't be that bad either.

I guess what I'm trying to say is.....there are things you can do to ease the strain on the compressor to make this work.