Fermentation chamber with multiple compressors?

[douglasbarbin]

I recently built a fermentation chamber out of an old cabinet and a 1.7 CF mini fridge. It's the typical setup that you see, where the door of the fridge is taken off and the front of the fridge is inside the fermentation chamber, with a computer fan circulating the air around. It's large enough to hold 2 fermenting buckets or carboys.

I think that it's insulated and sealed fairly well. I used 2 layers of blue foam board (1/2" thick per layer, I think...might be 3/4"). I used silicone caulk around the seams, and I have A/C weather-strip foam around the door (the chamber opens from the front, one door only). I am thinking about using some spray foam to seal up anywhere that the caulk might have missed, but I don't expect this to help a whole lot.

So far, with the compressor running all the time, it has maintained a temperature of anywhere from 63 degrees F to 68 degrees. The fermentation chamber is in my shed, and it's summer in Louisiana, so it is HOT in there. It is typically 85 F at the coolest, and often well into the 90's. So, the fermentation chamber seems to stay around 25 degrees below ambient.

Now, I am definitely satisfied with this so far. I bought a Ranco ETC-111000 so the compressor (hopefully) won't run 24/7. However, I can't help but think that I would like to get it a little cooler, maybe even cool enough to lager. My first idea was to augment it with a peltier cooler, but I know that those are terribly inefficient. My next idea was get a window A/C and either put it on the fermentation chamber, or at least in the window of the shed so that I can bring the ambient temperature down a bit. Again, not the most efficient thing in the world.

My latest idea is this: what if I gutted another mini-fridge and put the cooling plate inside the fermentation chamber, to help the first fridge. I know I am working that 1.7 CF fridge pretty hard, and frankly I am surprised that it has cooled so well for having to cool an area so much larger than it was designed for. Perhaps another compressor will help to take some of the load off of the first one.

Any thoughts or comments? I haven't seen any threads where somebody used more than one mini fridge for their fermentation chamber, but I'm thinking it could work. Or am I crazy? Should I be happy with what I have, and move it inside or wait until winter if I want cooler temps?

 

[BigFloyd]

I believe that you would achieve a better result if you put your time, effort and dollars into picking up a used full-size unit (fridge or freezer) and regulating it with your Ranco. That way you would know for sure that it could handle the task, even lagers.

If you want to still use your current setup as a second chamber, you can always pick up an STC-1000 to control it.

 

[douglasbarbin]

That's what I was afraid of. Anyone else want to chime in?

 

[broadbill]

That's what I was afraid of. Anyone else want to chime in?

Stands to reason that is will help, hard to tell if you are going to get out what you are going to put in though. I don't think you are going to get to lager temps under any circumstances though (no data to back that assertion up I'll admit). If that is a requisite for you, you should probably abandon this project and go with the Craigslist freezer as BigFloyd suggested.

 

[outterbanks]

Go to the state surplus warehouse. I bought 2 refrigerators for $20 each.

 

[Benzene]

I have two mini fridges on mine, both controlled by 1 stc 1000. Keeps my chamber cool no problem, in a Dallas tx garage that easily hits 95+ this time of year. Im holding 62 degrees.

 

[douglasbarbin]

I have two mini fridges on mine, both controlled by 1 stc 1000. Keeps my chamber cool no problem, in a Dallas tx garage that easily hits 95+ this time of year. Im holding 62 degrees.

Right, but I'm looking for more like 42 degrees.

 

[douglasbarbin]

Go to the state surplus warehouse. I bought 2 refrigerators for $20 each.

Not sure if Louisiana has one, but that sounds like a good idea if we do.

 

[outterbanks]

All state universities, hospital, and jails sell their old stuff at the end of the physical year. Here in NC July starts a new year. The surplus center in Raleigh, NC had over 20 refrig last week. At little banged up but work great.

 

[rappell]

As long as you use a small fridge it will not be very efficient as it is only designed to get so cold. It will have to run more to keep up with the ambient temp. Better solution is to get a small chest freezer and use your temp control. By design it is more than 3 times as efficient and you don't have to build anything. I bought a 7 CF freezer for $60 on Craig's list and it will hold two 5 gal and two 2.5 gal kegs, only once they get down to temp, they only run a few min every couple of hours and we are up in the high nineties to low 100s here.

Side note. Just bought 4 acres outside Lafayette and hope to move back there within 4 years. Sure miss LA!!

 

[flars]

'I think that it's insulated and sealed fairly well. I used 2 layers of blue foam board (1/2" thick per layer, I think...might be 3/4").'

That doesn't seem like a sufficient amount of insulation for a hot climate. Add two more inches of Blue Dow and see what happens.

 

[broadbill]

'I think that it's insulated and sealed fairly well. I used 2 layers of blue foam board (1/2" thick per layer, I think...might be 3/4").'

That doesn't seem like a sufficient amount of insulation for a hot climate. Add two more inches of Blue Dow and see what happens.

I think a better option would be to try this thing inside your house and see if it is going to perform any better. It could be a lack of insulation, but its probably an undersized refrigerator.

Why throw good money after bad with more insulation?

 

[BigFloyd]

Why throw good money after bad with more insulation?

Exactly. Once it's all said and done, you could have more wisely put the money toward a full-size fridge or freezer.

 

[douglasbarbin]

Well, I moved it inside and so far the temperature has dropped about 10 degrees.

 

[broadbill]

Exactly. Once it's all said and done, you could have more wisely put the money toward a full-size fridge or freezer.

I think this should be the take-away from this thread. I appreciate DIY as much as the next guy, but sometimes you just can't beat the pre-purchased approach.

As an aside, for all of these builds that crop up on this board, it would be interesting to hear how many are still in operation 1 year later. My guess is that many get scrapped for better options a few months they are built. Those that stand the test of time, it would be good to know how/what they were built with.

 

[douglasbarbin]

I think this should be the take-away from this thread. I appreciate DIY as much as the next guy, but sometimes you just can't beat the pre-purchased approach.

As an aside, for all of these builds that crop up on this board, it would be interesting to hear how many are still in operation 1 year later. My guess is that many get scrapped for better options a few months they are built. Those that stand the test of time, it would be good to know how/what they were built with.

Time for some thread necromancy! Just an update, I still use this thing, although it's in my garage now and only good for ales. I have a chest freezer on a temperature controller that I also use, and it is a lot more efficient. But in all fairness, I still use this thing, and it also makes a handy work table.

 

[broadbill]

Time for some thread necromancy! Just an update, I still use this thing, although it's in my garage now and only good for ales. I have a chest freezer on a temperature controller that I also use, and it is a lot more efficient. But in all fairness, I still use this thing, and it also makes a handy work table.

Thanks for the update! Glad to hear you got your system worked out.