Dual Zone Upright Freezer Fermentation Chamber

[tflew]

I found this freezer on CL for $20 and even though the coils run through the shelves I figured it was worth a shot. My plan is to build a chamber around it with a shelf in the middle so that I can get two levels of buckets/carboys. What would be the best way to set up the two zones for separate temperature control?

I was thinking of taking the door off and using that on the front of box. If I add insulation on the back of both chambers (essentially closing off the fermenting chamber from the freezer) and add fans for both the top and bottom chamber, would that work? Would the temperature controllers just control the fans and could the freezer just be plugged straight into the wall, or would it need to be plugged into the colder of the two temperature controllers? The freezer shelves would pretty much become dead space but I don't want to attempt to bend them out of the way.

The opening to the freezer is about 4ft tall and 2ft wide.

What are your thoughts and any advice would be appreciated

 

[reynolds5520]

What you're suggesting would work. It would be sort of like a frost free refrigerator in that the evaporator is behind a panel with fans moving the cold air where you need it. With a controller on the compressor too, you may be able to keep that section warm enough to actually be frost free.

The down side to that method is that all of the cubic feet of space in there is lost to the back section.


You could also make your horizontal baffle run to the back of the freezer. Then use one controller to cycle the compressor, set up to control your upper section. That would need to be the colder section. Then another controller to cycle fan(s) to move cold air from the upper section through your lower (warmer) section. Functionally that is pretty much the same as what you described, but it lets you use the space in the freezer cabinet.

 

[tflew]

Yea I guess the problem with my idea is losing the functionality of the shelves/space that is already there. If I ran a horizontal baffle (is that the same as a shelf?) to the back of the freezer, how would that allow me to have two different temperature zones. Both sections would be exposed equally to the cooling coils and if the temperature controller ran off of the compressor wouldn't both zones be about the same temperature?

Unless I still walled off the back on the back with insulation, losing the functionality of the shelves on top how would I be able to really separate the temps?

Thanks

 

[reynolds5520]

The frost layer on the coils in your pictures shows that the refrigerant is circulated through the coils from the top down. So long as the top chamber isn't set too cold, the cycle times shouldn't be long enough for the coils in the bottom section to get very cold.

An insulated baffle between the sections could be cut from foam board.