5000 BTU Fermention Chamber

I normally don't brew in summer. It's just too hot in the garage and my basement HVAC is set to 72. I normally ferment in the basement in winter where I keep the temperature set at 68F. The keezer is also down there. But it is hard on the back carrying 5-10 gal of fermenting wort down the stairs to ferment, then back up to the garage for crash cooling in a fridge and kegging. Then back down to the keezer. The basement is already completely finished with wood flooring, my office, a full bath, an entertainment room and a 14x26ft seven seat, two tier home theater. So, there will be no extensive remodeling to allow an electric brewery.

We have a 3-car garage and I have made a portion of that a brewing area. I put together this 4x4x4 ft fermentation chamber using 4x4 lumber, OSB, foam insulation and a new GE 5000BTU AC unit that is controlled by an STC-1000. The AC is a very simple model with only an on/off switch. So it should work well with the STC-1000 or a CoolBot. It is on casters so I can roll it around. It fits into my little brew corner and it will have shelves that sit on top of it to store my equipment. Yesterday, I wired up the controller and plugged in the AC. That was before I added any insulation or doors. The top was also not affixed and only sitting in place. I propped two OSB panels by the door opening and fired it up. With all those potential air leaks and NO insulation, I achieved 18.3C (~65F) in about 10 minutes. The ambient temperature was about 88F.

Here is a photo taken last night after I added most of the foam insulation. BTW, the floor is 4x4 with OSB on top and bottom. The 4" space is tightly filled with blow-in insulation. All seams are now caulked and I still need to add some Great Stuff foam as well as some weather stripping, doors and maybe a tile floor.

The second photo shows the AC unit and you can also see the STC-1000 near the front side.

What are your plans to drain the ac? Anything special or just drain to a bucket? How much are you into this project financially, if you dont mind sharing. I am trying to build a Ferm chamber on somewhat of a reasonable budget, that is why I ask.

Oh and looks very nice so far! Are you sure you want to use tile though? I would think laminate would be much more durable, without the hassle of worrying about glass carboys being on it

The AC unit rests on a u-shaped platform made of 2x4 lumber. I am mounting a pan under it with drain that will go right out the garage and into a Nelly R Stevens Holly.

I figure I'm into this about $400. The little GE AC unit was on sale back in April for $99, so I bought it and yesterday was the first time I ever even plugged it in. It is also surprisingly quiet. As far as the floor of the cooler, I don't use glass carboys. I use these which range from about 8gal to 13 gal in capacity. The blue tops are about 7.5 gal, the Speidel is 30L and the two red tops are 13gal. A tile floor would just make it easier to slide them in and around.

tonight, I removed the AC unit's temperature sensor and located it outside the chamber. I set the STC-1000 to 10C and boom, right down to 10C. I don't even have doors on it yet...just two pieces of foam blocking the opening.

All I need to do now is add the doors. I couldn't resist checking the capacity. That is all my fermentation capability inside. I do have one 7gal bucket from Northern Brewer that is not in there. This represents approx 56.5gal. I doubt I'll ever have more than 20gal fermenting at once.

Interesting!

WalMart has this for $99.84 right now...

http://www.walmart.com/ip/General-Electric-5-000-BTU-Window-Air-Conditioner-AET05LQ/20449871

ianw58 said:

Interesting!

WalMart has this for $99.84 right now...

http://www.walmart.com/ip/General-Electric-5-000-BTU-Window-Air-Conditioner-AET05LQ/20449871

Click to expand...

That looks very similar to the one I bought. But mine is even simpler with only one control knob. The analog controls are what you want, not digital, so that one will probably work. Then, just remove the front panel and carefully just bend the temp probe so that it runs down the side and out of the chamber to the outside. That keeps the compressor on until the STC-1000 shuts it off. I'm only going to be running mine at ale temps, so I hope I don't have a problem with freezing coils. If so, I may have to buy a CoolBot for $300. The CoolBot is really more for a true walk-in cooler.
CoolBot website: http://www.storeitcold.com/
This nano brewery in Buffalo uses CoolBots on their walk-ins:
https://www.youtube.com/watch?v=-2aauAB2poc

This is the one I bought on sale for $99.
http://www.brandsmartusa.com/Brand/158941/detail.bmp?gclid=CMPkqL2KkbgCFcNj7AodnEoAUg

What are the amps on that ac unit?

SavoryChef said:

What are the amps on that ac unit?

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It is 10 or 15 amps...I think. I'm out of town, but will look after I return. The STC-1000 is 15 amps and I have an in-line 10amp fuse on the main power in.

It's 4.9 amps.

Well, the GE I have that is very similar to that one is 4.9. The site in the post only shows an EER, which is not the amps. It is the Energy Efficiency Rating. Apparently another government BS rating to confuse things.

In another thread about AC units, someone else said they are typically pretty low. So I'm inclined to believe you. I run it with a 10amp fuse and when the compressor kicks on, there is no poof.

I should have named this 5000BTU Crawl-In Fermentation Chamber. During my final steps, I actually got inside. Even my 5'-11" 200lb mass could get inside since it is 4x4x4. I think I may eventually add some nice trim and/or paint...maybe even a logo to the doors. But for now, it is finished. I used some SS hinges and handles left over from a mahogany boat project. Not only do the handles open the doors, I also use them to pull it around. In a few months, I'll need to add some sort of heat. I have nice baseboard heater that would fit, but all the foam is flammable. I may just look at heat mats.

Have you looked into how often the compressor is running to maintain Ale temps? I'm interested in keeping low Ale to Lager temps and am in Houston. I'm guessing our temps and average humidity are pretty similar.

Yes, I have. While empty, it runs 45 seconds approx every 2 min to keep it at 15.5C. That is with only 1" of foam insulation in the sides and top. the bottom has 4" of green fiber insulation. The outer skin is 1/2" OSB. I may go back and add another inch of foam or maybe not. I think I'll find a few more of these threads and make the same inquiry about cycle times. I have the STC-1000 set for 15.5C with a 1C differential and 1min delay. At my house, we have not been over 90 but once this year. It is 84F right now. Winter it gets into the single digits some at night, but mainly 20s is about as low as we get.

One other thing: the probe is hanging in the air. In my keezer, I placed the probe into a 1L bottle of water. I don't know if I'll do the same here or not. I think that would be a good experiment and I know the run/cycle time would change a lot.

Okay guys, you were right. I took another 1L square bottle like I use in my keezer and filled it with water. I taped the probe to the outside and placed it inside. I set the STC-1000 to 19.5C (~67F). The temp reading started out around 70F and the A/C ran a couple of minutes. It stayed off a few minutes and ran through the cycle again. I knew the water inside the bottle had to equalize in temperature and after about two hours, I went back into the garage to check it. I got tired of waiting after more than 20min. I know for sure it is going longer than 30min between cycles. When it does cycle back on, it runs for maybe 1:30 and shut off. The temp continued to drop another .5-degrees Celsius. That is with only a 1L bottle of water and nothing else inside the 64 cu ft cabinet. I also ordered a 4" stainless thermowell that I'm going to thread through the cap of the bottle and I'll insert the probe into that.

Glad to hear it! Have you gotten anything fermenting in it yet? I definitely think i'm going to have to build one or 2 of these.

nice project! I might have to do something similar. due to space/shape/aesthetic issues, I'd rather do something like this than a keezer for chilling kegs to serving temps (I serve at 45). Any special wiring on the STC or did you just wire the cold to an outlet and then plug the AC unit into it? Is the STC probe ok for submersion? I didn't set it up like that in my bar fridge. It's just hanging int here.

limulus said:

That looks very similar to the one I bought. But mine is even simpler with only one control knob. The analog controls are what you want, not digital, so that one will probably work. Then, just remove the front panel and carefully just bend the temp probe so that it runs down the side and out of the chamber to the outside. That keeps the compressor on until the STC-1000 shuts it off. I'm only going to be running mine at ale temps, so I hope I don't have a problem with freezing coils. If so, I may have to buy a CoolBot for $300. The CoolBot is really more for a true walk-in cooler.
CoolBot website: http://www.storeitcold.com/
This nano brewery in Buffalo uses CoolBots on their walk-ins:
https://www.youtube.com/watch?v=-2aauAB2poc

This is the one I bought on sale for $99.
http://www.brandsmartusa.com/Brand/158941/detail.bmp?gclid=CMPkqL2KkbgCFcNj7AodnEoAUg

Click to expand...

While you have it open you could rewire it so the fan is always on when the compressor is running. Then it won't ever freeze up.

I'm wiring a 1-10 minute time delay relay to the fan on my A/C so I can keep the fan running for a couple minutes after the temp controller shuts the compressor off.

kcolby said:

Glad to hear it! Have you gotten anything fermenting in it yet? I definitely think i'm going to have to build one or 2 of these.

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I will have a 10gal batch in on Sat or Sun

Weezy said:

nice project! I might have to do something similar. due to space/shape/aesthetic issues, I'd rather do something like this than a keezer for chilling kegs to serving temps (I serve at 45). Any special wiring on the STC or did you just wire the cold to an outlet and then plug the AC unit into it? Is the STC probe ok for submersion? I didn't set it up like that in my bar fridge. It's just hanging int here.

Click to expand...

Just wire as normal with a cold side and a hot side, if needed. Yes, the probe is immersible in water. I had one in my keezer in vodka and it eventually failed. The new probe is in water. I ordered a thermowell to use in the fermentation chamber.

n240sxguy said:

I'm wiring a 1-10 minute time delay relay to the fan on my A/C so I can keep the fan running for a couple minutes after the temp controller shuts the compressor off.

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I'm trying to figure out how that would work with my controller. Once it reaches temp, it kills the power. I do not use mine as a walk-in. It is only at fermentation temps so it should not freeze. If I decide to run it at cooler temps, I will probably buy a CoolBot to control it. I have already had it down to 55 so I know I can use some cooler fermenting strains.

limulus said:

I'm trying to figure out how that would work with my controller. Once it reaches temp, it kills the power. I do not use mine as a walk-in. It is only at fermentation temps so it should not freeze. If I decide to run it at cooler temps, I will probably buy a CoolBot to control it. I have already had it down to 55 so I know I can use some cooler fermenting strains.

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It's probably not completely necessary. I've seen people put 3-5 computer fans on the front of the A/C to keep it from freezing up. I used to sell electrical parts like this, so I have a passion for it. You would run your temp control to a receptacle as usual. The off delay relay will have its own hot and neutral line run to it. You cut the hot line to the fan. Run the two lines you now have to the relay. It works just like normal, except it keeps the fan on for a predetermined period of time after your controller tells it to turn off.

Could you use a second STC with a longer delay setting to run an external fan?

Sure. I always keep an extra stc-1000 as a backup since they are only $19. I suppose you could just place a small electronics fan onto the coils to run all the time. I also keep one of those as a spare.

Weezy said:

Could you use a second STC with a longer delay setting to run an external fan?

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You could do that, but I just bought my off delay relay for $7.95 shipped from china. Can't really beat that price. Also, I think the A/C's fan would work better than a little computer fan. I don't have the cfm ratings on the A/C fan, but I know it's pretty high based on it's size. You would also be blocking flow of the main can by using little fans in front of it.

The new thermowell came today. I drilled a hole in the cap and screwed in the thermowell. Easy-peazy.

I brewed a 10gal batch last night. After 15hrs, the temp is solid on 68F on the fermenter. I had to set the STC-1000 at 19C (~66F). I assume some heat is being generated by the fermentation and a lower setting is required.

n240sxguy said:

[...] The site in the post only shows an EER, which is not the amps. It is the Energy Efficiency Rating. Apparently another government BS rating to confuse things.

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Sorry to butt in, but the EER is not some "BS rating to confuse things", it's just the efficiency. It's the ratio of cooling rate to electric consumption. An AC with an EER of 10 uses 10% more electricity for the same amount of cooling than an AC with an EER of 11. Just measuring the peak amps while the compressor running doesn't tell you anything about the power consumption (although it is useful to know so that you don't exceed wiring and controllers).

If more people understood what the EER meant, nobody would buy those crappy ACs they sell at Walmart with an EER of 8.5. You spend way more money on electricity to run an AC than you do to buy it, so it makes sense to get a more efficient model wiht an EER of 10+.

limulus said:

I brewed a 10gal batch last night. After 15hrs, the temp is solid on 68F on the fermenter. I had to set the STC-1000 at 19C (~66F). I assume some heat is being generated by the fermentation and a lower setting is required.

Click to expand...

Having the thermistor in a separate vessel isn't going to give you the response you need to control ferm temps in another vessel, since the fermenter's heat is never going to influence that separate vessel. You can and should just rig up something to hold the thermistor to the side of the fermenter. I cut a 4"x4" or so piece of thick exercise mat material and taped it to the side of my fermenter. I just jam the thermistor between the foam rubber and the tank. It works well.

hvjackson said:

Sorry to butt in, but the EER is not some "BS rating to confuse things", it's just the efficiency. It's the ratio of cooling rate to electric consumption. An AC with an EER of 10 uses 10% more electricity for the same amount of cooling than an AC with an EER of 11. Just measuring the peak amps while the compressor running doesn't tell you anything about the power consumption (although it is useful to know so that you don't exceed wiring and controllers).

If more people understood what the EER meant, nobody would buy those crappy ACs they sell at Walmart with an EER of 8.5. You spend way more money on electricity to run an AC than you do to buy it, so it makes sense to get a more efficient model wiht an EER of 10+.

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Ok. I'll give you that it's not B.S., but it does confuse things. When someone is talking about overloading wiring because an A/C has an ERR of 10, they are confusing it with the actual amperage.

Weezy said:

Having the thermistor in a separate vessel isn't going to give you the response you need to control ferm temps in another vessel, since the fermenter's heat is never going to influence that separate vessel. You can and should just rig up something to hold the thermistor to the side of the fermenter. I cut a 4"x4" or so piece of thick exercise mat material and taped it to the side of my fermenter. I just jam the thermistor between the foam rubber and the tank. It works well.

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Yeah, I re-taped the probe to the fermenter after I brewed on Sunday. The 1L bottle with the thermowell is only to get the temp up to my set point and hold it there w/o cycling on and off so much. I'm going to brew a bourbon barrel porter later this week and I will move the probe to that fermenter.

n240sxguy said:

Ok. I'll give you that it's not B.S., but it does confuse things. When someone is talking about overloading wiring because an A/C has an ERR of 10, they are confusing it with the actual amperage.

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I will have to check the numbers in my manual. I am sure they are not good. It is a 5050 btu GE unit that was on sale for $99. I have a three zone HVAC system in my home and my power bill can be >$300/mo. A few more $ won't make much difference.

limulus said:

I will have to check the numbers in my manual. I am sure they are not good. It is a 5050 btu GE unit that was on sale for $99. I have a three zone HVAC system in my home and my power bill can be >$300/mo. A few more $ won't make much difference.

Click to expand...

That's the A/C I just bought. I don't remember seeing the ERR number because I wasn't looking for it. I think it runs 4.9 amps. I would imagine the efficiency of the unit in our application, dollar wise anyway, would be more influenced by how well you insulate your enclosure. A less efficient unit in a well sealed enclosure could still be reasonable to run. A more efficient unit would be even better. I didn't feel like getting the more efficient unit because it cost more, and wasn't analog.

hvjackson said:

Sorry to butt in, but the EER is not some "BS rating to confuse things", it's just the efficiency. It's the ratio of cooling rate to electric consumption. An AC with an EER of 10 uses 10% more electricity for the same amount of cooling than an AC with an EER of 11. Just measuring the peak amps while the compressor running doesn't tell you anything about the power consumption (although it is useful to know so that you don't exceed wiring and controllers).

If more people understood what the EER meant, nobody would buy those crappy ACs they sell at Walmart with an EER of 8.5. You spend way more money on electricity to run an AC than you do to buy it, so it makes sense to get a more efficient model wiht an EER of 10+.

Click to expand...

Just out of curiosity, how is the ERR number calculated? Is it more a matter of how well the A/C is designed as far as coil design and airflow, or is it influenced by the "intelligence" of the A/C controller changing fan speeds or compressor run time? Just wondering. If its the latter, we may be changing that ERR value by trying to control it with a different temp controller.

n240sxguy said:

Just out of curiosity, how is the ERR number calculated? Is it more a matter of how well the A/C is designed as far as coil design and airflow, or is it influenced by the "intelligence" of the A/C controller changing fan speeds or compressor run time? Just wondering. If its the latter, we may be changing that ERR value by trying to control it with a different temp controller.

Click to expand...

EER is calculated as the cooling rate (in BTUs / hr) divided by the average electrical consumption (in watts), under reference conditions meant to be representative of typical use. E.g. I think 90˚F outside air and 80˚F inside return air. All of the things you mention (coil design, airflow, fan & compressor logic) can affect the EER. (If you've ever taken a thermodynamics class, the EER is identical to the Coefficient of Performance except that it uses different units.)

You're correct that by operating the AC at cooler temperatures than designed (most fermentation chambers are probably in the low 60s, and some people even use ACs to make a conditioning room even colder) the AC may not be performing as efficiently as its EER rating. It's also likely that by overriding the fan / compressor logic you get additional losses.

BTW. Just looked at my $99 GE A/C box. EER is 9.7

n240sxguy said:

BTW. Just looked at my $99 GE A/C box. EER is 9.7

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I guess that is not too bad. Mine does not run very much, so I think I'll be okay. I now have three batches of primary fermentation going:
1. Vienna Blonde 10gal
2. Bourbon Barrel Porter 5gal
3. Pliny 5gal
I also have a plastic bin with grains for:
1. IPA
2. American Brown
3. Dunkel (lager)

There is also a bucket of DampRid that I keep in there.

I also have decided to add some additional flooring inside. I'm down to tile or the clear epoxy that you use on bar tops. I could even place pictures or something under the epoxy. I should probably tidy up those wires a wee bit. I have some of the flexible cable stuff that is used for TV/Stereo wires. Plastic conduit may be better though.

Oh yeah, the little blue container on the right side is 1-pint Maker's Mark soaking in 3oz of oak cubes. That will be added to the secondary of the Bourbon Barrel Porter in a couple of weeks.