Fermentation Chamber Design for 15 Gallon Plastic Conical

[BFD_BrewGeek]

My basement generally stays at ~68*F year round. This works pretty well for Belgian ales and some pale ales and IPA's...but I've always wanted to control fermentation temperatures more closely to be able to affect the quality of the final product, cold crash without racking to smaller vessels, and have the ability to ferment at lager temperatures. So that got me thinking of building a fermentation chamber to house my current fermenter, which is on wheels so I can roll it in and out of the housing as needed for filling, cleaning, etc.
Planning to use a 5,000 BTU window air conditioner to do the cooling, controlled with a two stage BrewPi PID controller (http://www.brewpi.com/). Not sure that I need to heat in a 68* basement. Temperature sensors, one in a thermowell inside the fermenter and the second in the cooled space inside the chamber. The chamber would be constructed of 2" rigid building insulation with 2x4 frame, just enough to support the insulation and air conditioner. The opening would be covered with a removable insulation panel. See sketches...

 

[BFD_BrewGeek]

Any thoughts or ideas would be appreciated...

Thanks in advance.

 

[debo0126]

I think it looks like a good plan. The AC you will be using will not need to be very big for that space. Instead of a removable door of insulation I would recommend you put some 1/4 in Luan on the foam and hang it on hinges. My experience has been that you think something is safe and out of the way only to find out one of your kids likes pretending its a board and do karate on it.

 

[BFD_BrewGeek]

I think it looks like a good plan. The AC you will be using will not need to be very big for that space. Instead of a removable door of insulation I would recommend you put some 1/4 in Luan on the foam and hang it on hinges. My experience has been that you think something is safe and out of the way only to find out one of your kids likes pretending its a board and do karate on it.

Thanks! I think a hinged door would be a good addition...

 

[muhteeus]

Awesome project. Subbed.

 

[madscientist451]

The AC unit will be putting off some water. You'll need some way to catch that water and either a hose to a floor drain or a bucket you can empty.
Your conical cart looks very well made, I like the design. It looks like you used nails? You might want to
put some long deck screws in where you can, nails don't hold all that well when hammered into end grain. Your 15 gallons of beer will weigh 125 lbs and those nails could start to work loose over time.

 

[nhwrecker]

Even though you're planning on using the chamber for just one 15 gallon fermenter, you may want to consider making it big enough to hold other beer for aging and/or fermenting. Also, make sure that it's big enough to have good air flow over and around your stand - the drawing looks like you're planning on a snug fit - which would preclude cold air from getting all around the conical.

 

[BFD_BrewGeek]

The AC unit will be putting off some water. You'll need some way to catch that water and either a hose to a floor drain or a bucket you can empty.
Your conical cart looks very well made, I like the design. It looks like you used nails? You might want to
put some long deck screws in where you can, nails don't hold all that well when hammered into end grain. Your 15 gallons of beer will weigh 125 lbs and those nails could start to work loose over time.

I used 4" deck screws to put the fermenter cart together...its pretty solid...good suggestion...thanks!

 

[BFD_BrewGeek]

Even though you're planning on using the chamber for just one 15 gallon fermenter, you may want to consider making it big enough to hold other beer for aging and/or fermenting. Also, make sure that it's big enough to have good air flow over and around your stand - the drawing looks like you're planning on a snug fit - which would preclude cold air from getting all around the conical.

Very good points...I need to make the chamber big enough to allow air flow top to bottom...I only have 1" clearance to the chamber wall now...I'll look at increasing clearance to ~4" all around...the additional volume should be a negligible load impact for the 5,000 BTU A/C unit.

I considered some additional space for multiple fermenters, kegs, etc...but decided to keep it make the design modular, since the temp for fermenting won't work for lagering/cold conditioning...something like this...

 

[miked597]

How are you going to get the a/c unit to go below 60 to cold crash? I'm in the process of a similar build and was thinking about getting a coolbot. Or do you have a better cheaper idea?


Sent from my iPhone using Home Brew

 

[atoughram]

Looks familiar....

Conical

Ferm Chamber - now has an AC unit...

Consider the Cheap Brewpi for control - mine holds thermowell temperatures to within half a degree.

 

[BFD_BrewGeek]

How are you going to get the a/c unit to go below 60 to cold crash? I'm in the process of a similar build and was thinking about getting a coolbot. Or do you have a better cheaper idea?


Sent from my iPhone using Home Brew

Plan A is to hack the a/c unit to operate as an independent cooling unit controlled by my BrewPi by isolating the fan and compressor circuits and isolating the ambient temperature sensor...I bought a cheap 5000 btu unit with rotary mechanical controls (i.e. not electronic)...when it shows up we'll see how feasible it is to identify and access all of the components and controls without totally reverse engineering the controls...
Plan B is going the coolbot route, but I already have the BrewPi up and running so I'd like to avoid that added cost.

 

[BFD_BrewGeek]

Looks familiar....

Conical

Ferm Chamber - now has an AC unit...

Consider the Cheap Brewpi for control - mine holds thermowell temperatures to within half a degree.

Awesome build! Are you controlling your a/c unit at the power mains or were you able to hack into the unit to control the fan and compressor by the BrewPi? How did you handle the ambient sensor? What are you using for a heater?
I'd really appreciate any advice you have.

Thanks!

 

[BFD_BrewGeek]

Rethinking the size of the chamber, based on some of the comments in this forum...circulation around the fermenter and additional space for a few carboys...also, the 2" foam insulation comes in 4' wide sheets, so why cut it if you don't have to?

Also added the door...found some cheap freezer door hardware here: http://www.sourcingmap.com/brushed-...-degree-door-hinges-silver-tone-p-191363.html

 

[BFD_BrewGeek]

I noticed that the last design I posted needed a door sheet that was 4'4" wide...that won't work very easily, so I narrowed the door opening to accommodate a 3'0" door and the fermenter still fits through the opening:

 

[BFD_BrewGeek]

BFDbrewPi is assembled and tested...24oz watermelon slurpee used to simulate the heating mode...waiting for A/C unit to arrive to start hacking controls...

 

[atoughram]

Awesome build! Are you controlling your a/c unit at the power mains or were you able to hack into the unit to control the fan and compressor by the BrewPi? How did you handle the ambient sensor? What are you using for a heater?
I'd really appreciate any advice you have.

Thanks!

The A/C unit had mechanical controls and I wired them so the compressor is always on. So when the main power to the A/C is energized via Brewpi the compressor starts and the fan runs.

I have three temp sensors on the system. Room (Ambient), Refridgerator (Ambient chamber temp), and Beer (a thermowell into the conical). I'm not sure which one you want to know about. I've also wired in an STC-1000 set to 0c, which the mains for the A/C unit pass through the cool relay and the thermistor is installed low on the evaporator coils. This acts as a freeze stat keeping the A/C unit from freezing up.

I've got one of these heating the chamber up as needed.

 

[WPStrassburg]

Also added the door...found some cheap freezer door hardware here: http://www.sourcingmap.com/brushed-...-degree-door-hinges-silver-tone-p-191363.html

How do you like the hardware? The latching handles look pretty decent and I might pick some up for the back bar cooler I have that needs some handles. They ship from China or somewhere overseas?

 

[BFD_BrewGeek]

How do you like the hardware? The latching handles look pretty decent and I might pick some up for the back bar cooler I have that needs some handles. They ship from China or somewhere overseas?

Pretty decent for the price...definitely fits the bill for a homemade cooler...
The description says they were brushed satin nickel, but they shipped polished chrome...no big deal to me...
They ship from China. Took about a month for delivery.

 

[BFD_BrewGeek]

Started framing over the weekend...

 

[BFD_BrewGeek]

Finished framing and insulation and hung the door last weekend...

 

[BFD_BrewGeek]

The freezer door hardware worked pretty well...and it looks like it's sealed pretty well too. It pulls a pretty good vacuum when you open the door.

I still need to cut the hole in the insulation wall for the air conditioner, rewire the a/c controls, mount the air conditioner, and test with the BrewPi.

 

[Minbari]

love it!

just need to paint the whole thing white and it will look like a commercial walk in

 

[atoughram]

looking good!!!

 

[BFD_BrewGeek]

Hacked the air conditioner control to bypass the thermostat and freezestat...turns out you don't need to be an electrical engineer to figure this one out...lifted the two red wires going to the thermostat and spliced extensions. Ran the extensions through a hole that I drilled in the plastic chassis...landed the extended thermostat leads on the BrewPi cooling SSR....

 

[BFD_BrewGeek]

Tested the new control setup with the a/c still disassembled, confirmed that the BrewPi was in control, then I reassembled the enclosure and mounted the a/c in the hole that I cut in the insulation wall. Will have to comb out the fins on the condenser coils after wrestling that pig into the hole...the cooler space temperature sensor is hanging just below the a/c for the first tests.

 

[Minbari]

SSRs are not overheating with no heatsinks?

 

[BFD_BrewGeek]

First tests got the cooler space down to 35*F in ~10 minutes in Fridge Constant Temp. mode on the BrewPi and no load in the cooling space. Then the BrewPi kicked off at 37 the a/c on minimum temperature setting. The cooler space temperature rose back up to 60*F pretty quickly...later testing with the fermenter in place loaded with 15 gallons of water helped to stabilize the temperature when the a/c cycled off.
I did have the evaporator coil freeze up once when I tried to take 15 gallons of 70*F water down to 35*F in one step to simulate a cold crash...the a/c ran for 20 minutes straight, space temp got down to 37*F, then started to rise...I shut everything down, opened the door and confirmed the coil froze up.
So...then I had to leave for the airport, but my future test plans include increasing the fan speed from low to high, taking the air filter out to increase air flow and increasing minimum space temp to 39*F. If I still get coil freezing, I'll try adding fans inside the cooler space to blow warmer air from the space back on the coils.

 

[BFD_BrewGeek]

SSRs are not overheating with no heatsinks?

No overheating yet...switching frequency is pretty low...I plan to install in 4/0 electrical boxes with knockouts removed for protection and to sink heat...just in case...

 

[atoughram]

Heat sinks are not really necessary with low continuous current. I've got an 25a SSR on my refer without a heat sink and it's been working that way for a few years now. You cant feel any heat coming from it while the fridge is running.

Nice build! I'd be interested in seeing if you build up ice on your evaporator when cold crashing. Mine iced up in my similar cabinet but my insulation isn't near as good.