This is an automated fermentation chamber to keep my fermenting beer at a constant controlled temperature. It is made from an old Dresser someone was throwing out at the dumpster in my community, guts from a small mini fridge, and controlled with an STC-1000 Thermal Micro-Controller. I also made a separate "Swamp Cooler" which goes inside the Chamber to help maintain temperature of the fermenting beer and relieve some of the stress on the compressor unit.
Step 1: Installing Mini Fridge Internals Into Dresser
After an epic battle with the mini fridge and trying to muscle out all the internals and plumbing without bending or crimping anything I put them to the side and started work on the dresser. this particular dresser had 4 drawer bays. The drawers were not in this dresser when I made off like a bandit with it from the dumpster area, so I removed all the spacers besides the last bottom one. The bottom one will serve as the floor to the Fermentation part of the unit, while the space under that houses all the compressor components and electronics needed to run. left inside the dresser were two very thin particle board sheets that separates each drawer cavity. I used this to create a bit of a void between the compressor compartment and fermentation floor since the compressor will heat the floor up during heavy usage times and could affect the chambers temperature. I filled this void with "Great Stuff" spray insulation foam while also lining the roof of the compressor compartment with Thermal Shield from Home Depot. Once I figured out the basic setup and layout of my chamber. It was time to get to the Insulation.
Step 2: Insulating the Fermentation Chamber and Installing Doors
I purchased 3x3ft, 1 Inch insulation foam boards from Home Depot and a few rolls of Gorilla tape. I then carefully cut the foam boards to fit snuggly to the walls and very carefully made sure there were no gaps in between the boards for the cold air to escape. Now I know you're thinking that Gorilla Tape wont stop the air from escaping, but this is just the first round of insulation going into the chamber. I also applied a ton of Gorilla Glue to the back of the foam boards so they were glued tightly to the walls of the dresser with no air gaps.
Once all sides were complete, I added the second of the particle boards on top of the floor piece of insulation to add strength and also shield against the heat from the compressor I mentioned in the last step. Once the first layer of insulation was done it was on to adding the Foil backed heat shield layer along with foil thermal tape on all the cracks. Once every surface of the chamber was covered with the second layer of metallic insulation I ran some cool down and holding checks for the next two days to see 1. How long it takes to get the ambient temperature down my fermentation temperature of between 60 and 75 degrees, and 2. How long could I hold the ambient temperature while the cooling unit was switched off.
My test run yielding some promising success but I could tell that increasing the size of the chamber was making the compressor work extremely hard. I knew I needed to come up with a way to cool the compressor down better than was being done by the heat exchanger. I was able to overcome this by adding a powerful PC fan from and old PC I had lying around that switched on when the unit was in cool down mode. Once I added the PC fan blowing on the compressor I noticed an immediate decrease in the cool down times! Also I was able to hold the ambient temperature for a few hours without the unit being powered on. Any home brewer knows it takes a decent amount of time for the wort to cool down during primary fermentation but once the wort is chilled it takes very little energy for the compressor to keep it cool.
Step 3: Controlling the Temperature
There are many different ways to wire this controller and I chose to keep it simple. I wanted to be able to remove the control system with very minimal effort if I ever wanted to move it to another chamber. I used spare PC power cables as my main power cable. I also purchased 2 - 3 prong female wiring receptacles as well as 3.5ft of cable rated for the job to use for the receptacles. I have an earth ground all the way through on this wiring just in case of any short so I do not get electrocuted or set my apartment on fire. I am pulling far less amps then this controller can handle so this configuration is great. I could have hard wired all the power plugs from all the devices but again I aimed for simplicity in this build.
The power for the swamp cooler as well as the temperature probe go through small drilled opening into the main chamber and are sealed with great stuff foam. I have this controller set for my target fermentation temperature of 62F (Controller is in Celsius), with a +/- 1 Degree variable to switch between Heat and Cool. The temperature probe runs into a special stopper called a "Thermowell", which is a stainless steel tube sealed on the immersed end. This way I get the actual Wort temperature instead of the surrounding ambient temperature in the chamber. The clear vinyl tube is the bubbler I made just in case the beer decides it wants out of the carboy!
To ease the strain on the Fridge Compressor I built a swamp box to go inside the chamber which is completely removable to allow for more storage in the fermentation chamber if needed. The swamp box is a plywood box which has thermal shield lined inside and out, that I swap frozen 2-Liter bottles when needed. The fan pulls air down through the top of the box over the frozen bottles and out of the fan exhaust which blasts right onto the Carboy. With the thermal lining I can get 2-3 days use out of two frozen bottles so its not that bad.
Once all these things are in place this Chamber can be left on its own without constant monitoring for the correct temperatures! There is still more to be done to this chamber to make it more aesthetically pleasing, so keep watching this Instructable as it unfolds! This is my first ever Instructable so hopefully I have explained everything. Let me know what you Guys and Gals think in the comments!