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Fermentation Refrigerator/Freezer advice needed

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Kevin Power

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I have an upright refrigerator/freezer with a Johnson temp controller installed. It works great and has plenty of room in the lower fridge section for 2 large carboys. The top freezer section is just wasted (very cold) space. It seems like such a waste to make this area so cold just to get the fridge part down to fermentation temp. I was thinking if I could open some holes between the freezer part and the fridge below it might work more efficiently (running less time). I was afraid to start cutting holes since there could be coils or refrigerant plumbing going between them. Has anyone had experience with this?
 
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Kevin Power

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Thanks. Glad I asked rather than breaking out the sawsall first. So it would probably be bad to cut into the freezer floor. Do you know if it's possible to enlarge the vent. My freezer stays very cold which seems like a waste.
 

ong

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Thanks. Glad I asked rather than breaking out the sawsall first. So it would probably be bad to cut into the freezer floor. Do you know if it's possible to enlarge the vent. My freezer stays very cold which seems like a waste.
I store hops in the freezer part. (But mine is a kegerator, so pretty consistent temps.)
 

IslandLizard

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Thanks. Glad I asked rather than breaking out the sawsall first. So it would probably be bad to cut into the freezer floor. Do you know if it's possible to enlarge the vent. My freezer stays very cold which seems like a waste.
If you have 2 thermostats turn the one for the freezer down, and experiment with the setting on the fridge one.

The vent may have a fan in it, at least in more modern models. Do some searches for your brand/model, you may find a schematic or other info on the construction and placement of the vent. I'd say it's in the back.

Hops should be stored deep frozen, so if that top section defrosts regularly due to low thermostat settings and the Johnson regulator, I wouldn't use it for hop storage.
 

IslandLizard

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Not sure about top freezer fridges, but most freezers work better and more efficiently when containing dense and heavy products. The worst is a (near) empty freezer, it keeps cycling. Together with lowering the internal thermostat, filling that freezer cavity with some water bottles may help to keep temps more constant in there. Now when the fridge section requests cooling, the freezer needs to kick on, so the extra mass may or may not be advantageous. That remains the bigger question.
 

wilserbrewer

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Your other choice is to use a converted chest freezer and fight the condensation if you have much humidity.

Don’t let your unused freezer space bother you so much lol as you could have far worse issues :)
 
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Thanks. Glad I asked rather than breaking out the sawsall first. So it would probably be bad to cut into the freezer floor. Do you know if it's possible to enlarge the vent. My freezer stays very cold which seems like a waste.
Well, actually your original idea might work fine. But I'm not sure how condensation would be handled - that's how these fridges work - instead of having the lower refrigerator cavity being surrounded by cold coils, as in a chest freezer, the humidity is just removed. It's that water vapor that carries energy (heat), so when it's removed the cavity becomes colder. The vapor is removed in the freezer, where the water must condense.

I guess I'm just thinking out loud here :) It would probably work fine, but you'll have to deal with getting rid of moisture, just as the chest freezer folks do. Damp Rid, unless somehow you can funnel it to the drain below the evaporator fan / defrost coils.

If you do cut, don't assume there aren't wires in there. As stated above, there will be some sort of damper that allows air to move between freezer and fridge. Might be powered, maybe not.
 

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If you do cut, don't assume there aren't wires in there. As stated above, there will be some sort of damper that allows air to move between freezer and fridge. Might be powered, maybe not.
This is a slightly stale thread but as I've been trying to figure out how I want to proceed with my chest freezer/refrigerator/fermentation chamber/keg serving cooler (ha) I've been doing some research.
Often times, you can tell how a refrigerator is built by looking at repair site drawings. Most of the freezer/refrigerators I've been looking at have drawings on sites such as Searspartsdirect.com or other repair sites. The drawings show the evaporator coils for most of these models being behind the back wall of the freezer section. True, there may be wires in the floor of the freezer but you can obtain clues on the repair site as well. Many of the inexpensive freezer/refrigerators use a bimetal thermostat, which runs straight back along the ceiling of the refrigerator section. There may be other wires but if you're determined to cut, and you can't tell exactly where those wires run, just punch through with a screwdriver and slowly widen out the hole to expose the insulator layers.
Make sure you identify drawings for your exact model of appliance. Otherwise, you're taking your chances.
These freezer/refrigerators really aren't that complicated. As has been mentioned, they're usually cooled by the freezer alone. Basically, when the refrigerator temperature sensor rises and hits it's trip point, it opens the damper and runs a fan to circulate cold air from the freezer. When it goes below it's set temperature, the fan turns off and the damper closes. I'm not an appliance guy so I can't say it there's any electrical connection between the refrigerator functions and the freezer. I suspect not.
My current project is to determine if I can split the refrigerator section of a freezer/refrigerator in two, add a damper to the added section, bypass the bimetal thermostat and use one side for a conical fermentor, the other for keg chilling. I'm playing with the idea of putting a wall into the freezer section to make it smaller. As others have mentioned, the freezer doesn't need to be so large. I may cut a hole in the ceiling of the keg chiller section, up to the front of the freezer (with the installed wall behind it) and installing taps into the freezer door. We'll see. I'm still searching this site to see what others have done.
As always, I'd appreciate any comments that could both point me in the right direction as well as steer me clear of disaster. My brain tends to skew towards disaster.
 

Dland

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I am sure all of the modifications you have outlined above are possible.

Most household refrigerators are already fridge freezer combos, with all of the compromises in efficiency, chamber separation, odor exchange etc w one compressor.

Have at it as much as you want, but might get better results in two separate units running in their design parameters, temp wise....it would take some engineering, and a fairly robust compressor to assure both chambers are at desired temps at all times.

This is not to say your idea could not work, ....
 
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This is a slightly stale thread but as I've been trying to figure out how I want to proceed with my chest freezer/refrigerator/fermentation chamber/keg serving cooler (ha) I've been doing some research.
Often times, you can tell how a refrigerator is built by looking at repair site drawings. Most of the freezer/refrigerators I've been looking at have drawings on sites such as Searspartsdirect.com or other repair sites. The drawings show the evaporator coils for most of these models being behind the back wall of the freezer section. True, there may be wires in the floor of the freezer but you can obtain clues on the repair site as well. Many of the inexpensive freezer/refrigerators use a bimetal thermostat, which runs straight back along the ceiling of the refrigerator section. There may be other wires but if you're determined to cut, and you can't tell exactly where those wires run, just punch through with a screwdriver and slowly widen out the hole to expose the insulator layers.
Make sure you identify drawings for your exact model of appliance. Otherwise, you're taking your chances.
These freezer/refrigerators really aren't that complicated. As has been mentioned, they're usually cooled by the freezer alone. Basically, when the refrigerator temperature sensor rises and hits it's trip point, it opens the damper and runs a fan to circulate cold air from the freezer. When it goes below it's set temperature, the fan turns off and the damper closes. I'm not an appliance guy so I can't say it there's any electrical connection between the refrigerator functions and the freezer. I suspect not.
My current project is to determine if I can split the refrigerator section of a freezer/refrigerator in two, add a damper to the added section, bypass the bimetal thermostat and use one side for a conical fermentor, the other for keg chilling. I'm playing with the idea of putting a wall into the freezer section to make it smaller. As others have mentioned, the freezer doesn't need to be so large. I may cut a hole in the ceiling of the keg chiller section, up to the front of the freezer (with the installed wall behind it) and installing taps into the freezer door. We'll see. I'm still searching this site to see what others have done.
As always, I'd appreciate any comments that could both point me in the right direction as well as steer me clear of disaster. My brain tends to skew towards disaster.
I'd suggest converting a freezer. What you're attempting to do sounds sketchy at best.
 
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All, based on what I've read here in the forums, I'm going to acquire a chest freezer/refrigerator and modify for temperature control. Seems the least expensive method of true "hands off" temperature control. I don't really want to swap ice bottles in a bag, etc. and glycol coolers seem pretty expensive. What size chest is needed (interior dimensions) to accommodate 2 x 5 gallon fermentation buckets? Are there any tall enough to accommodate a Catalyst type fermenter?

Advice is much appreciated!
 

Jonakr

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I'd suggest converting a freezer. What you're attempting to do sounds sketchy at best.
I'll second this. With a chest freezer and Inkbird, I can ferment two 5 gallon carboy/buckets at once, with room for two 1 gallon carboys on the hump. I have an upright freezer-fridge combo Keezer with room for 4 kegs in the fridge section, and the entire freezer compartment for: yeast, hops, etc.
 

marc1

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I have an old fridge/freezer combo that I use for fermentation. I cut the divider between the fridge and freezer out. There was a wire for the fridge light to avoid. Works great, plenty of headroom now.
 
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