kickrjason
Well-Known Member
Who out there has built a fermentation chamber based on a window A/C unit? I would like to know what has worked and what has not worked?
Ok apparently i need to be more specific in my questions to avoid responses like that........ Fyi i know how to search the forum.
I would like to know from the people that have built them that use them on a constant basis.
1) what have you run into as far as condensation problems.
2) have you wired in a digital controller for more precise temperature management.
3) what kind of power consumption do you insure from running the unit
Thank you
I've built a fermentation chamber that uses a window AC unit. See here: https://www.homebrewtalk.com/f51/my-fermentation-chamber-build-question-262827/
It works great. I got the Johnson A419 controller. No condensation problems.
Here are a few things I learned in the process, in no particular order:
AC units have a built-in thermostat that will probably turn the coolant compressor off at 60-ish degrees F. You'll need to bypass that. In my case, I was lucky because the AC unit isn't digital. Bypassing the AC unit's built-in thermostat was really easy with a little wiring logic.
Make sure you attach your external thermostat's probe to something with thermal mass. I have mine wrapped in plastic and floating in a little gallon jug of water so the Johnson controller only kicks on the AC unit when the liquids in my chamber are above a certain temperature. This is important because air loses energy way faster than a 5 gallon batch of beer. If you don't do this your AC unit will cycle many times an hour and burn the compressor out.
I don't have condensation issues because my AC unit only cycles once an hour or so. Don't skimp on insulation sheets, Great Stuff, caulking, or the seal around your door. The seal around your door is crazy important to seal well. I made mine big enough to actually sit in, and I did just that to see where the leaks were. Wherever I saw light, I improved the seal around the door until it was tight. If I were to build this over again, I would plan my door construction way better. Hell, I could fix it now, but I'm lazy. Works great.
If you're using an AC unit, you can get things really cold, as long as you can bypass the AC unit's thermostat, so take advantage of that and make the thing as big as you can afford to. When sizing the external dimensions, consider making the thing portable and narrow enough to fit through doorways/stairwells. Instead of crappy pine 2x4s for the framing I bought some decent maple. Glad I did, it took way less wood to build the skeleton and as a result I can move it very easily.
Great Stuff is insanely sticky and will completely F up your skin! SWMBO was not happy about my cancer hands.
Insulation sheets are cheaper than ruined batches of beer, so go nuts, treat yourself to the 2" thick high R factor stuff.
Consider the future. I might start fermenting in kegs one day, so I made sure I could fit a keg with a fermentation rig fitted to it inside in terms of height. (I didn't plan space for conicals, but that's another story altogether.)
The Johnson controller is nice, but you might as well go for something with two channels on it, one for heating, one for cooling. Even if you live somewhere that doesn't get too cold in the winter, you might want the heating option later for a saison or something Belgian that wants a higher temp.
Can't stress this enough: GO BIG!!! I feel a little sad when I see fermentation chambers that can only fit 2 carboys. An AC unit puts out a ton of cooling power, even a little 5000 BTU unit. Make the most of it! I spent a couple hours ripping apart a minifridge to get the guts out, but for my money, the AC unit is way more powerful and efficient.
Power consumption is probably a few bucks a month. What's it worth to you to have awesome beer year round? This is probably the best investment you could make in beer quality, aside from oxygenation. FEED YO YEAST, SON!
Hopefully that answers some of your build questions! Holler if you have more.
ilikethetrees said:I've built a fermentation chamber that uses a window AC unit. See here: https://www.homebrewtalk.com/f51/my-fermentation-chamber-build-question-262827/
It works great. I got the Johnson A419 controller. No condensation problems.
Here are a few things I learned in the process, in no particular order:
• AC units have a built-in thermostat that will probably turn the coolant compressor off at 60-ish degrees F. You'll need to bypass that. In my case, I was lucky because the AC unit isn't digital. Bypassing the AC unit's built-in thermostat was really easy with a little wiring logic.
• Make sure you attach your external thermostat's probe to something with thermal mass. I have mine wrapped in plastic and floating in a little gallon jug of water so the Johnson controller only kicks on the AC unit when the liquids in my chamber are above a certain temperature. This is important because air loses energy way faster than a 5 gallon batch of beer. If you don't do this your AC unit will cycle many times an hour and burn the compressor out.
• I don't have condensation issues because my AC unit only cycles once an hour or so. Don't skimp on insulation sheets, Great Stuff, caulking, or the seal around your door. The seal around your door is crazy important to seal well. I made mine big enough to actually sit in, and I did just that to see where the leaks were. Wherever I saw light, I improved the seal around the door until it was tight. If I were to build this over again, I would plan my door construction way better. Hell, I could fix it now, but I'm lazy. Works great.
• If you're using an AC unit, you can get things really cold, as long as you can bypass the AC unit's thermostat, so take advantage of that and make the thing as big as you can afford to. When sizing the external dimensions, consider making the thing portable and narrow enough to fit through doorways/stairwells. Instead of crappy pine 2x4s for the framing I bought some decent maple. Glad I did, it took way less wood to build the skeleton and as a result I can move it very easily.
• Great Stuff is insanely sticky and will completely F up your skin! SWMBO was not happy about my cancer hands.
• Insulation sheets are cheaper than ruined batches of beer, so go nuts, treat yourself to the 2" thick high R factor stuff.
• Consider the future. I might start fermenting in kegs one day, so I made sure I could fit a keg with a fermentation rig fitted to it inside in terms of height. (I didn't plan space for conicals, but that's another story altogether.)
• The Johnson controller is nice, but you might as well go for something with two channels on it, one for heating, one for cooling. Even if you live somewhere that doesn't get too cold in the winter, you might want the heating option later for a saison or something Belgian that wants a higher temp.
• Can't stress this enough: GO BIG!!! I feel a little sad when I see fermentation chambers that can only fit 2 carboys. An AC unit puts out a ton of cooling power, even a little 5000 BTU unit. Make the most of it! I spent a couple hours ripping apart a minifridge to get the guts out, but for my money, the AC unit is way more powerful and efficient.
• Power consumption is probably a few bucks a month. What's it worth to you to have awesome beer year round? This is probably the best investment you could make in beer quality, aside from oxygenation. FEED YO YEAST, SON!
Hopefully that answers some of your build questions! Holler if you have more.
kickrjason, do you have an AC unit already? If not, have you thought about using a freezer? Food for thought, I know you've already built your chamber ...
It answered a lot of my questions. Thank you for such a thorough reply.
I have an Stc-1000 that it wired up to a mini fridge right now. Would I wire the controller up the same way to power the A/C unit or should it be relayed? Can the controller handle the power that the unit will pull? you said you had to wire up the built In Thermostat. Did you bypass it or remove it entirely and just set it to run when plugged in?
I think I got a junk fridge and now am looking for a better replacement.
On a plus if and when I switch to an A/C unit I will gain more space.
Sent from my iPhone using HB Talk
kickrjason, do you have an AC unit already? If not, have you thought about using a freezer? Food for thought, I know you've already built your chamber ...
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