Big huge refrigerator? Yes please!

Unfortunately, the photos of this project have been permanently lost. The unit has since been disassembled since I bought a different house, so I cannot retake new photos. I apologize!

I received by new BCS-460 three days ago, and excitedly set to work building what will be an all-inclusive fermentation and refrigeration control chamber. The choice to use the BCS-460 was based on the desire to have one unit control it all, and to have network accessibility so I can check all my fermentation stats (and log them) remotely via my laptop.

I thought I'd share the process with everyone.

In my basement, I decided on an area near the sump pump well, to deal with any condensation that may drip off of the A/C unit. I took an old Amana 6k BTU A/C unit, tore it apart, cleaned it, and rewired it to remove the thermostat. Other than an on/off switch, it's now a dumb unit and runs when it has power.

I built a 4' x 8' x 4' framed box, with two access doors and full internal insulation. All sides and the top are insulated, including from the floor. Expanding foam was then shot into every crack and crevice to make things as airtight as possible. Both doors are tightly gasketed with stick-on weather strip.

Here's a 3D model of the chamber in Sketchup, in case anyone is considering building something like this, and wants to fiddle with my design.

ferm_chamber.skp



There's a temperature probe inside the chamber, and a 25A relay (eBay) controlling the A/C unit.

Right now, the entire chamber is one volume of air, and one temperature. The BCS program looks as follows:

• 0: Compressor Wait. Exit Condition: timer0 <= 0. timer0 is a 15:00 timer. Goto 1.
• 1: Hold. Exit Condition: temp0 >= 44. Goto 2.
• 2: Cool. Assert out0 (A/C compressor). Exit Condition: temp0 <= 40. Goto 0.

The process starts automatically when power is applied. The purpose of the Compressor Wait state is so that if I open the doors and cause a temperature spike, or if the power drops out while the compressor is running, I can guarantee that the compressor will never be asked to cycle ON less than 15 minutes after it was last cycled OFF. This should significantly extend compressor life.

As is, with only ~8 gallons of beer stored in it, it is able to maintain 42f (23f < Ambient) by running the compressor for two minutes every twenty minutes. I'm very pleased.

The chamber is so large, because soon it will be upgraded. I am installing a movable gasketed internal wall to divide the space. The refrigeration cell will then be smaller, and I will have a fermentation/lagering/aging cell as well. The movable wall will have computer fans in it, which the BCS will control to exchange air with the refrigeration cell. Thereby allowing me to have a chamber that is both < Ambient, and > Refrigerator. The ferment chamber will be equipped with 3 thermistors. One to monitor air temp, and two more to drop in thermowells in active fermentors. The fermentors (Sanke kegs) will be equipped with electric blankets, which the BCS will independently control. In this way, I can theoretically ferment 20 gallons of beer at once, while maintaining +/- 1f temperature control, per fermenter. They can even have different set temps at the same time.

The main purpose of this design was to kill three birds with one stone (BCS) and also require only one cooling source (window A/C) for the entire process.

This thing will hold a HUGE amount of kegs and bottles. I'm estimating even after I reduce the size of the refrigeration cell, I can still easily keep 12 cases of bottles and 10 kegs in there. Now I finally have to opportunity to keep and age beers properly!

Thoughts/questions appreciated! Here's some pictures:



















NOTE! Please see my update to this build further down the thread for important changes I had to make!

That is friggin awesome!

Wow, thats awesome

Very ..... cool!

Looks good. Be sure to watch out for ice on the evaporator coil with such a large cooling space and/or install a dehumidifier.

Just out of curiosity, why didn't you go all out and make it a walk-in? I apologize in advance if you're a person of short stature.

Will you be fermenting and serving from there?

lamarguy said:

Looks good. Be sure to watch out for ice on the evaporator coil with such a large cooling space and/or install a dehumidifier.

Just out of curiosity, why didn't you go all out and make it a walk-in? I apologize in advance if you're a person of short stature.

Click to expand...

I really laughed out loud on that one.

Set up looks great though!

lamarguy said:

Looks good. Be sure to watch out for ice on the evaporator coil with such a large cooling space and/or install a dehumidifier.

Just out of curiosity, why didn't you go all out and make it a walk-in? I apologize in advance if you're a person of short stature.

Click to expand...

Humidity is going to be an issue, yep. I considered a dehumidifier, but they make heat and also ice up readily at these temps unless they are the expensive variety with a defrost cycle. I'm going to throw in a bucket of Damp-Rid from Lowes, and see if that keeps it dry.

Why you little... I can walk right in there!

No, the size was determined based on materials on hand. I had pretty much everything I needed raw materials wise, except a single sheet of foam laying around from a prior project. So I built to the size I had materials for is all.

Plus, now I use the top of it as a giant shelf for kegs and fermentors.

IrregularPulse said:

Will you be fermenting and serving from there?

Click to expand...

Fermenting certainly. I have not decided about serving yet. I would like to set up a dedicated tap in my garage that runs from a keg in here if I can. The problem is getting the line resistance right for a draft system, and keeping the beer cold in the lines. It would take ~10' of line to get from here to a tap in the garage.

That is awesome! Sweet build.

cscade said:

I'm going to throw in a bucket of Damp-Rid from Lowes, and see if that keeps it dry.

Click to expand...

FWIW, you can get Damp-Rid a lot cheaper at a Pool supply store -- it's just Calcium Chloride, which is used to raise water hardness. You can also regenerate it by heating it in an oven to drive off the moisture, although at the $1/lb that it costs at the pool store, this isn't really an issue.

In the winter, I think it's also sold as "Ice Melter" at hardware stores, just make sure you get CaCl2 (calcium chloride), and not sodium chloride, potassium chloride, or something else weird.

shortyjacobs said:

FWIW, you can get Damp-Rid a lot cheaper at a Pool supply store -- it's just Calcium Chloride, which is used to raise water hardness. You can also regenerate it by heating it in an oven to drive off the moisture, although at the $1/lb that it costs at the pool store, this isn't really an issue.

In the winter, I think it's also sold as "Ice Melter" at hardware stores, just make sure you get CaCl2 (calcium chloride), and not sodium chloride, potassium chloride, or something else weird.

Click to expand...

Nice tip! Thanks!

I buy 50 lbs bags of calcium chloride at Home depot during the winter. Its like 30 or so a bag.. I try to get the 50% off broken bags when I can . That aint my shoes squeaking when I walk

cscade said:

I would like to set up a dedicated tap in my garage that runs from a keg in here if I can. The problem is getting the line resistance right for a draft system, and keeping the beer cold in the lines. It would take ~10' of line to get from here to a tap in the garage.

Click to expand...

Cape Brewing talks about how he runs/cools his lines starting at post #9....I bet that he'd give you some pointers.

Later,

I've updated the OP to contain a Sketchup 3D model, in case anyone is into modeling their builds!

First of all, I think this is epic! If I didn't live in a flat I'd be all about doing this on a smaller scale for myself. Although in my current situation I can't even convince my room mates to allow me to turn our end table into a fermentation chiller for lagers ha ha ha. I sent this to my dad though, he enjoys lagers but as of yet hasn't done any lagering while brewing! Maybe this will inspire him to create something that'll elevate him to the next level of brewing.

cscade said:

I would like to set up a dedicated tap in my garage that runs from a keg in here if I can. The problem is getting the line resistance right for a draft system, and keeping the beer cold in the lines. It would take ~10' of line to get from here to a tap in the garage.

Click to expand...

Have you considered running your beer line through a length of large I.D. tubing that has cooled glycol running through it? A glycol reservoir in the coldest part of your fridge should have no problem keeping the tap on the end of a mere 10' of beer line cold if you wrap it in insulation.

SeamusMac said:

First of all, I think this is epic!
...
Have you considered running your beer line through a length of large I.D. tubing that has cooled glycol running through it? A glycol reservoir in the coldest part of your fridge should have no problem keeping the tap on the end of a mere 10' of beer line cold if you wrap it in insulation.

Click to expand...

Thanks!

I'm looking into something like that. Either air-exchange by PVC pipe loop to a box, or glycol. I have not explored pumping glycol though. I'd like to keep equipment expenses minimal.

Very cool! Now i'm tempted to do this in the corner of my garage.

Crawl-in refridgerator? TM!

As an update to the OP, I need to let anyone considering a similar build know about the severe failure that followed my initial posting after the build.

After running smoothly for about two days, I was confident the system was stable. I was away from home for 24 hours, and returned to disaster. When I checked the BCS control panel, I discovered to my horror that the A/C unit had been running for 15 hours solid, and the temperature in the refrigeration unit was 51f. What the heck had happened?? Ice! I had to completely tear apart the A/C unit, and removed about six pounds of ice from the evaporator coil, and lots and lots of water from the chassis.

When I reassembled the unit, I relocated the temperature probe to be in direct contact with the coil and rewrote the state machine as a stopgap measure so I could limp along with halfway cold beer while I solved the problem properly. I knew this wouldn't last though, I simply needed more data and more control than one thermistor and one relay could provide. Without more data there was no way the BCS could ever be aware of, and remedy, an ice condition while simultaneously maintaining a set temperature.

I contacted Derrin at http://www.brewershardware.com who happily agreed to build me a custom thermistor assembly with no stainless probe end. He quickly turned around three probes for me (all three custom in their own way, I needed the other two for other projects) and dropped them in the mail the same day.

When they arrived, I tore apart the A/C unit again, this time mounting an additional relay inside the control panel housing of the unit. It, in tandem with the relay I already had controlling the main power to the unit, would allow me to control the circulation fan separately from the A/C compressor. I covered the thermistor Derrin had assembled with heat shrink to prevent shorts against the A/C evaporator coil, and inserted the probe directly into the fins. This would allow me to check for ice. I then placed a second temperature probe inside a glass jar full of water. This would allow me to maintain a set liquid temp rather than a set air temp.



After reassembling everything, I ran the relays manually for two hours (via the BCS of course), collecting data about the way my particular A/C unit interacted with the space it was cooling. Based on the output from the new sensors, and what I was seeing in the logs, I developed a new state machine to cool the chamber. Here's a flow chart:



It should be pretty self explanatory, but please feel free to ask questions. State 0 is first to prevent the compressor from cycling fast if there is a power outage, and in between phases. This is covered in the OP. Originally, this was 15 minutes, but after research into compressors it seems 3 minutes is sufficient to prevent premature wear in my use case. State 0 also performs double duty to defrost the coil after a cooling phase. The only confusing bit might be the two timers counting up in states 1 & 2. They simply exist so that when I pull up the BCS control panel to check on the unit, I can see how long it has been in either one of those states. The state machine does not use them. Here's the machine in action, after the contents of the chamber stabilized temperature.



As you can see, the system now consumes no power for upwards of 45 minutes, waiting for the chilled liquid to rise one degree. Once it does, the compressor will run as many six minute cool/defrost cycles as needed until the liquid temperature in the chamber hits 38f. It will then return to an idle. Ambient air temp is irrelevant and ignored.

I am extremely pleased with the results. It can now keep the beer colder, using less power, with more idle time, and far less likelihood of things going pear-shaped. The state machine is flexible so that as weather conditions (mostly ambient humidity) change, the defrost cycle may extend beyond 3 minutes (via State 1) as much as needed to prevent icing.

So, if you're considering a build like this using a single probe temperature controller instead of a multi probe configurable machine like the BCS, I advise strongly against it. If you were only gunning for ferment temps instead of refrigeration temps however, it would probably be fine.

Cheers!

cscade said:

After running smoothly for about two days, I was confident the system was stable. I was away from home for 24 hours, and returned to disaster. When I checked the BCS control panel, I discovered to my horror that the A/C unit had been running for 15 hours solid, and the temperature in the refrigeration unit was 51f. What the heck had happened?? Ice! I had to completely tear apart the A/C unit, and removed about six pounds of ice from the evaporator coil, and lots and lots of water from the chassis.

Click to expand...

I hate to say it, but I told you so.

lamarguy said:

Looks good. Be sure to watch out for ice on the evaporator coil with such a large cooling space and/or install a dehumidifier.

Click to expand...

In concept it's simple - build a box and attach a window unit. In reality, it's more difficult because you really need a defrost heater that runs periodically. I imagine the BCS could be programmed to periodically defrost the evaporator like any frost free freezer.

Glad to hear you've devised a better method to monitor the internal temperature and be alerted to ice formation.

lamarguy said:

I hate to say it, but I told you so.

Click to expand...

Liar! You love to say it!

I know, I know, you did tell me so! When I saw the 51f temp I knew instantly... ICE before I even opened the box. I was still surprised it happened after a seemingly random time period though.

The BCS could definitely handle a true heated defrost cycle, but right now that seems like it's not needed. It's keeping the beer at a solid 38f with only an automated fan cycle for defrost. If I tried to go colder I'm sure I'd hit the wall very suddenly though.

I hate to sound like a shill, but this controller is freaking awesome. I'm really impressed with the flexibility and configurability. I'll continue this thread once I have it controlling ferment temps separately in the same chamber!

OK, so when you done with yours, when can you start on mine?
That is really nice. Please once you get all the gotcha's worked out, I hope you can find the time to put together a full on "how to" worthy of a sticky.
Now if only I could find the space in my apartment.

cscade said:

Liar! You love to say it!

I know, I know, you did tell me so! When I saw the 51f temp I knew instantly... ICE before I even opened the box. I was still surprised it happened after a seemingly random time period though.

Click to expand...

Ha, ya got me!

Also, John Beere built a walk-in and solved his ice problem with separate fans that constantly recirculate air over the evaporator coil to prevent icing. Perhaps something to consider as well.

cscade said:

Plus, now I use the top of it as a giant shelf for kegs and fermentors.

Click to expand...

I would beef up the structure if you're going to store heavy things on top, those 2x2s aren't all that strong for putting a full keg on. I'd want at least 2x6 "joists" framing it out to support it, maybe with a post going from the outside back down to the floor?

I might be suggesting a bit of an overbuild, but in the end it would really suck if everything in there got crushed because you put too much weight on top.

I solved the icing issue with thermowells which slowed down the temp response and, like John Beere, I blow air directly on the coils with a 4" fan. Before the thermoewells the ac unit kicked on every time the fridge changed 3 degrees. Which could easily happen just opening the fridge door. With the thermowells it now takes about 50 minutes for the medium in the well to rise 3 degrees. It also takes longer for it to drop when the ac is running. End result is that the ac now runs about once an hour for about 9 mins. No ice ever builds up.

This is my fridge:

Outer dimensions: 7'6"W X 3'6"D x 5'6" H



It is been running at 37 for the past couple months without a hiccup. I love my "big huge fridge."

First, great build, and write up!

One thing for others who are planning to build a similar fridge. How are you going to get that thing out of the basement if you ever move or want to sell it? If I'm counting blocks correctly, that baby is approximately 44" x 96"

Too late for yours, so i guess this thought is for future builders.

Anyways. rockin cooler. I hope to have one myself someday

sjlammer said:

First, great build, and write up!

One thing for others who are planning to build a similar fridge. How are you going to get that thing out of the basement if you ever move or want to sell it? If I'm counting blocks correctly, that baby is approximately 44" x 96"

Too late for yours, so i guess this thought is for future builders.

Anyways. rockin cooler. I hope to have one myself someday

Click to expand...

Just a quick update for everyone, it's been running perfectly for a month and a half now. The grey line at 38 degrees is how consistently it maintains the liquid temp.

Go build your own!

So, I can use my computer for more than playing solitair.

Do you have an alarm rigged to alert you to an out of range (temperature) condition?

pilotdane said:

Do you have an alarm rigged to alert you to an out of range (temperature) condition?

Click to expand...

I do not. I'm operating on the crossed-fingers method. I do get into it pretty much every day though, so I'd be aware reasonably quickly it things went haywire.