Advice on 3 zone fermentation chamber idea

[The_Gerbil_Brewer]

I have an upright freezer I currently use for fermentation and have an idea on how I can use it for 3 separate temperature controlled chambers. I am building 2 insulated boxes that will sit above the freezer and can each hold 2 carboys. I plan to put a 10-15 gallon container of water in the freezer with 2 aquarium pump. I’m going to run copper tubing (not sure exact length but thinking 25-50’ for each chamber) from the pumps to the chambers and run along the wall of the chamber, returning back to the water tank in the freezer. Temperature controllers will cycle the pumps on and off.

I want to use the freezer for lagers/cold storage, one chamber for ales, and one chamber for long term sours. The freezer will therefore be between 32 – 50F (depending on whether fermenting or lagering) and the 2 water chilled chambers will be kept to keep fermentations in the 68-70F range. The chambers are in the back entry of my apartment so for the fall/winter/early spring keeping them at ale fermentation temperatures will be done with a heat pad. In the summer I expect that area to get up into the 90s.

Does anyone see any issues with this setup? Specifically:

- Will 10-15 gallons of 32-50 degree water chilled in a freezer be enough to maintain 68-70 fermentations in the summer heat?

- Will an aquarium pump be powerful enough to pump the water up a total height of 3 feet above the container and through 25-50ft of copper tubing?

- Would I be better off running a duct from the freezer to the fermentation chambers and have temp controllers cycle fans on and off to cool via forced cold air?

Thanks for any advice!

 

[Mtn_Brewer]

I would doubt you would get adequate heat transfer, especially during active fermentation and the coils, pump and water would take up a lot of room. Also, there is the potential for a serious mess, if you spring a leak. I think you would be better off with air circulating.

It just so happens that my Racer X build came up under similar threads below. You may want to take a look at the duct work. It's been working great.

 

[The_Gerbil_Brewer]

Thanks Mtn_Brewer. The capacity to chill effectively was definitely a concern of mine. Any idea on where the coils in an upright freezer run? Is it just the back? I'd prefer to cut holes and run duct work from somewhere besides the door so I don't have to disconnect every time I want to check on the fermentation. Since the freezer doesn't have much room around it for duct work, ideally I'd cut 2 holes in the top and install fans to blow cold air up through the floors of the chambers.

Thanks again for the advice!

 

[Mtn_Brewer]

I've made 2 keezers and the coils were different in both. Check with the manufacturer or drill a test hole.

You should also think about what probes and controllers to use. I prefer RTD's in thermowells but some put the probe in air or strap to the carboy. Thermowells are more accurate but can only monitor one carboy per chamber.

Good luck.

 

[The_Gerbil_Brewer]

I sent an email to Frigidaire but haven't gotten a response back. I found the attached schematic image here but can't say I can say if it tells me anything. It looks like the condenser is at the bottom back and the evaporator is the entire back of the freezer. From my layman's viewpoint, also taking into account what appears to be cold air vents coming from the back I'm tempted to believe that the cooling comes from the back and there are no coils in the top or sides of the freezer, but that could be the Heady Topper confidence talking. I'm not too keen on playing Russian roulette with test holes, so if anyone with freezer/fridge knowledge can weigh in it would be much appreciated!

 

[Stealthcruiser]

Is the inner liner, held in place by screws, or is it all one molded piece?

If the former, pull some screws, and have a look behind the panel / liner.

 

[The_Gerbil_Brewer]

Is the inner liner, held in place by screws, or is it all one molded piece?

If the former, pull some screws, and have a look behind the panel / liner.

I wish... it's molded and no apparent way to pop it off.