Fermentation chamber with window AC or Fridge guts

HBT members I am in need of a little guidance. I am ready to move from the waterbath/ice fermentation tub to a true blue fermentation chamber. I have both a spare window AC and an old fridge (bottom freezer). I would like to know the pro's and cons of purposing either for a fermentation chamber. If I use the fridge it will be dismantled to go into a custom cabinet. Please give me your thoughts/ideas.

 

Go for it! Rip that sucker apart, have a home brew and be sure to take lots of pics and post them so we can see

 

A/C - dramatically more powerful than the fridge and will cool a larger volume. Circulates air on it own. Requires modification to get to lagering temps. Prone to freezing up. Needs exhaust area and drainage

Fridge - designed to hit lower temps. Not designed to cool larger areas. Needs extra air circ for sure. If you gut it, it's kinda hard to replace if anything goes wrong. Fewer condensation issues.

 

Which is easier and prone to have fewer problems?

 

If doing 5 gallon batches the fridge is def your way to go. Won't need much gutting. Just a temp controller


Sent from myPhone

 

Well I have been doing 5 gallon batches but I just ordered a 13gallon stainless conical. I think the fridge guts will cool a cabinet big enough for the conical. So long as I have 4" of foam insulation all the way around it. :rockin:

 

I used 4" (two layers of 2") insulation on my ferm chamber I made with mini fridge guts. The compressor hardly kicks on anymore even near freezing.
Mine is roughly 2.5'd x 2'w x3'h so I'm sure your fridge will be able to keep up.
But. If I had an extra AC rather than an extra mini fridge laying around, I probably would have used that.

 

The fridge I have is a full size fridge. I thought about using the AC but I don't want to deal with the condensate from it running or the noise. I have pretty much talked myself into using the fridge (keeping the model and serial number tag so that I can order a part if anything goes bad and needs replaced) unless a more compelling argument is made.

 

Everyone has given you bad advice.

The only solution is to build 2 Fermentation Chambers one with the Fridge, and one with the AC unit.

Then you can still use all your 5 gallon stuff while using the 13 gallon Conical!

 

I use a fridge right now, but my keg fermenter barely fits into it. I have an A/C unit begging to be turned into a fermentation chamber, but I'm not sure how to use it.

It seems to me that the internal thermostat with turn it off no matter what the temp controller is set at. Do I have to get an A/C that has no thermostat and only has High/Low settings? Or do people break into them and dismantle the internal thermostat so the temp controller functions properly?

I'll be using it outside so venting/noise isn't much of an issue.

 

Hit the fridge man. Did it ,yself after much debate on the same topic and am damn glad i went that route. A couple cheap fans from walmart, and cheap personal heater also from walmart, and some fancy wiring with an stc1000 and that bad boy has femented 20+ brews with many differnt yeasts and no problems what so ever.

 

Summerland, I believe members open the A/Cs up and bypass some of the internals to make them run to get as cold as you want.

 

Cposten, plz post some pics of your set-up.

 

I'll have to post some pictures of mine - 5000btu window unit with a bypassed mechanical thermostat, STC-1000 wired in as a freezestat to keep the coils ice free, 200w Lasco personal heater from wally world, and brewpi keeping the temps in check. Enough room to put a 17gal conical in.

 

The best way to set this up is to cool the liquid directly not the air around it. Look at how the pros do it (water jackets). The temp swing can be dramatic if you are trying to adjust 5 or 10 or even 15 gallons of liquid by cooling the air (to drop the liquid a couple degrees means it will either take a long time or the air has to be super cold).

We are in the process of switching over to a system that has copper coils wrapped around the outside of a 5 gallon plastic carboy. The coils are filled with antifreeze that is circulated by a pump (which is on a temp controller). The antifreeze flows from the carboy coils to my freezer which is sitting next to it (and still fully functional to store food/etc) which has a heat exchanger in it (basically a radiator). This is a closed system, doesn't take up extra space or extra electricty. We have a ferm-wrap (think aquarium heater tape) wrapped around the carboy for the heat side. Then the whole works is wrapped with that aluminum bubble wrap stuff. I'll post some pictures tomorrow. It should be pretty slick!

 

I'm not sure you understand the physics here is you don't think that takes up extra electricity. Pumping liquid from a cold space, exposing it to ambient temps, and having much greater heat loss from your fermenter all make your system dramatically less efficient than just sticking the fermenter into a fridge.

 

What I've found is that running a mini-fridge in an extended fermentation chamber at between 55 and 70F leads to condensation issues inside the chamber, and hence mold. I've had to add a drain to the tray that sits under the cooling part (evaporator), routed to a gallon jug, but I haven't managed to get the system level enough to drain the tray properly yet.

With an AC unit, the condensate should be routed to the outside portion of the unit, and then to a drain plug, which you could connect to a tube and bucket outside of the chamber. Some of the condensate will be used by a slinger fan to help cool the hot side of the AC unit. The AC unit will dry the inside of the chamber quite effectively, so mold shouldn't be an issue.

I'm also wishing I had another fridge to use for lagering and/or serving cask beer at lower temperatures than the fermentation chamber that I can use at the same time. I'm quite tempted to rebuild the chamber with an AC unit, and put the fridge back together as a cask beer cellar/lagering fridge (Haven't made anything more lagerish yet than a steam beer because I can't reach true lager temps).

It seems to me that AC units are optimized for cooling a large volumes to 65-75F with significant air exchange and drying the air, while fridges are optimized for cooling a small fairly well sealed volume to 35-45F. Keeping their new uses somewhere close to that is probably a good plan. A larger fermentation chamber is somewhere between the two original applications. However, AC units are probably all rather massively over-specced for a reasonable* fermentation chamber, and so probably less efficient. Not sure what the right way to go is.


*If you have a 1 bbl system and 12 tap keezer, your definition of reasonable may be different to mine.

 

Our current fermentation chamber uses a minfridge & we have to keep a drip tray in the fridge section for the condensate (it fills about 1/4 gallon every few weeks). Maybe the smallest AC unit you can find & build your chamber plenty big...?

 

You are right, it's not going to be use zero electricity, but having a minifridge running to the max to cool a large space is much less efficient than 1 small pump. The freezer stays completely intact & is still in use for storing food & hops (so I'm writing that off in the electricity dept). The carboy is not sitting out in ambient air (I didn't mention in my earlier post that is is inside it's own cabinet & then wrapped with insulation to keep the cool coils only having to cool the beer). I'm currently using the old system with a fridge so we'll have to see how this new one compares on my electric bill... the main efficiency that I'm trying to get is consistent beer temps without the big swings when the yeast really takes off & the lag of an undersized fridge trying to keep the heat down.

 

" The freezer stays completely intact & is still in use for storing food & hops (so I'm writing that off in the electricity dept). "

That is where you go wrong. If you are running a heat exchanger through a freezer, you are adding all sorts of heat and will dramatically increase the workload of the freezer.

A much simpler way to avoid heat swings in a chamber is to just tape the probe to the side of the fermenter and cover with some insulating material.

 

I agree. Or use a thermowell that you can get for $10-25 and put the probe inside the liquid. A fridge will have no problem easily keeping the temp of the liquid steady. I use both a mini fridge (for 5 gallon batches) and a regular fridge (for 10 gallon batches) this way and have had zero problems.

The only issue is stepping up the size of the fermenter, which is what I think the point of this thread is. If you've going to use a space for a larger fermentation area (which I need to do since I'm stepping up to 20 gallon batches), which is better?

From what I can tell doing some research, it appears A/C will eb the way to go, especially if you're only doing ales. The A/C is much more efficient and should have no problems keeping a good temp.

I don't have the money for this, but it gives some good info on how to use an a/c for this purpose http://www.storeitcold.com/ . On that site they give specs for size of A/C to keep big cold rooms at 38*, so if you're only doing a small closet with good insulation and 60* it would probably need a super tiny unit.

Without using this, does anyone have any info on how to disable the thermostat? I don't feel like cracking open a $500 a/c unit that I have without having some sort of idea before hand, haha. I'm no electrician, but I have a decent understanding when it comes to following directions.

 

"Without using this, does anyone have any info on how to disable the thermostat? I don't feel like cracking open a $500 a/c unit that I have without having some sort of idea before hand, haha. I'm no electrician, but I have a decent understanding when it comes to following directions."

It really depends on the unit. It it's got dials on the front, it's likely to be a pretty simple design where you can easily bypass the thermocouple or even just bend the thing so go outside the chamber insulation. The more bells and whistles the unit has, the more complicated it will tend to be to work on.

This is a great use for craigslist/garage sale units. You really don't want/need anything high end.

 

It's a pretty high end model, but it's what I already have and I just put central air in the house so it will no loner be used. I don't know how many bells and whistles it really has, but it's digital and puts out a ton of cold air.

 

You could buy a coolbot to hook to your ac. http://www.storeitcold.com

 

bump

 

While I completely agree that "sharing" the cooling function of an existing freezer is not free energy by any means, there is something to be said for not having a second cooling machine running on its own. I think the system described is more electrically efficient than having a separate compressor, but probably not by much.

I understand where you were coming from though because I have a similar pet peeve when people say they chill their wort using ice made in their freezer because it's "free ice" since they already pay to cool that box.