Refrigerator Freezer Combo - To combine top and bottom or no?

[Dbilik]

Hi everyone,

I have searched through a bunch of threads but haven’t had any luck finding an answer to my questions/idea here, so I figured it was time to post it up.

I have a Kenmore fridge from 1998. It is freezer on top, fridge on bottom. Evaporator coils are mounted in the freezer with a ran to circulate air in the freezer and a thermostat to control the refrigerator temp below and a damper/vent to control the freezer temp. I have researched the way this works, and it basically seems like the refrigerator will kick on the compressor when the temp in the fridge gets too high. This in turn runs the compressor, cools both the freezer and refrigerator, and then kicks off. I would like to be able to turn this into.a fermenter, so I have the following ideas, but haven’t found anything to back up the crazier of the two.

1. Simply keep the fridge as it is for the most part, rewire the refrigerator thermostat only with either a digital replacement. Have a few options here, but basically I would change the temps which the refrigerator portion would call for the compressor to kick on at. Could essentially be controlled from room temp all the way down to where I wanted it. This seems to be the safer and easier solution.

2. I have temporarily removed the partition between the freezer and refrigerator portion, essentially combining the two spaces into one large space. I would install my thermostat controls to override the entire refrigerator/freezer combo by bypassing the existing refrigerator thermostat and installing an external one, maybe a Johnson controller I have laying around.

My questions...if I go with the first route and keep things in the freezer, I know this will work. But if I go with the second, I gain space and I am essentially using the cooling power from the entire evaporator coil in the one big space. I lose out on the auto defrost settings since I will be killing power to the entire unit, but shouldn’t need them since it won’t see temps below freezing. Aside from condensation, which should still run out, am I missing any reason why I shouldn’t consider the second option? The doors will still seal once I put the mullion pieces back in, and I could probably just override the thermostat to keep the defrost option and have a cleaner install. I don’t believe the freezer has its own thermostatic control, only the manual slider to control air recirculaion for the freezer. If I am not dropping the temps to below freezing or anywhere near it, I don’t think I would be putting too much additional stress on the compressor if I am only dropping 30-40 degrees F from ambient.

I’m sure i missed some details here. Been sketching out ideas for a while now.

 

[dyqik]

If it works as you describe, a concern with just controlling the fridge as is is that at higher temperatures, the freezer may not stay frozen, making it fairly useless and wasted space and energy. However, I'm not sure it can work like that - having the fridge at a high setting and low loss (not opening the door) would mean that the freezer could easily defrost if the door was used a lot.

A third option is to install a digital control for the compressor with its sensor in the freezer, and a second digital control with a sensor in the fridge to control the fan between them. Then you could keep the freezer as a useful freezer for hops etc. (or as a fridge), and control the fridge section independently.

With a Raspberry Pi or similar type DIY control setup this wouldn't really be any more expensive than a single control set up. Something like CraftBeerPi or Brew-Pi should be able to handle the control.

 

[Dbilik]

I think I will have to do an experiment here shortly with all of these ideas.

I think you might be right about the freezer not working as a freezer anymore if I am too high on refrigerator temps. Would be simple enough to test and find out and go from there and wouldn’t really require any equipment beyond what I have right now to test it all.

I like the DIY control setup, this is how projects get out of control.

 

[satph]

I removed the partition in my similar vintage over/under freezer/fridge. I control the temperature with an STC-1000+. It's used as a fermentation chamber. I didn't mess with any of the fridge internals (besides the partition), and plug the fridge into the STC.

Mine has the cooling unit above, and the fridge temp was controlled by the now removed damper, are you sure yours works the other way around? In any event, as long as fermentation temperature setting is above the temperature setting where the fridge will kick on, the external controller will control the unit.

You have all the parts. Give #2 a test run.