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The Ole' Window AC - Glycol Chiller Build

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hunter306

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Another stab at building a cheap Window-AC based Chiller. I snagged the Frigidaire Analog unit from the clearance section at Sears for 25.00 out the door... Add a 35 dollar cooler, a trusty STC-1000, and a aquarium wave generator and here it is.

First, build the cart, to keep the whole unit together - Added some basic caster wheels to move it more easily when it's loaded up with liquid:



Then tear the lid off and see what we're dealing with - Bend the chiller coil outward, and vertical to pass it into the cooler body. Throw away the whole face plate, that's not getting reused here. Remove the squirrel cage blower from the front of the blower motor to make room for the cooler. Rear fan remains intact.

There's not much to say about bending the copper- it needs to be done slowly and carefully and preferably not while the unit is cold. I eased it into this position with a lot of delicate bending.



Build a stand for the chiller coil, Using a little bit of aluminum angle bracket cut and bent by hand. If the coil inadvertently builds up ice, we don't want that extra weight stressing the copper tubing running back to the compressor. This should just help with some durability.





Assess the wiring situation. This was a manually controlled unit so it was fairly easy to retro fit with a digital controller (ITC-1000F from InkBird).

First, I removed the analog thermostat, and directly connected the control wire to the main 5 position switch to make sure this was going to work. By doing this, when the AC/FAN setting is switched on, the compressor will always run. This is the mode we want when we connect to the cold-side of our ITC, so the test seemed valid.

The two red wires are the controls: 1 runs to the compressor, the other to the High-Speed side of the fan. The white wire will not be used in our implementation, as that is intended for low-speed fan only.

Also worth noting, if you plug anything in to test-- that capacitor holds some juice when you unplug it, don't get willy-nilly with your screwdriver or fingers... or you'll get a nice little zap.







Next, I tied all my grounds together and added a 12ga wire tied to the body of the compressor and it's mounting stud. Easy way to maintain some level of safety afforded by the built in GFCI plug.

I used some crimp connectors and then simply screwed the group together incase I needed to expand later. Heat shrinked for good measure... Not totally necessary for the grounds.





Let's put the ITC-1000 in place: I simply traced out the hole with my square using the measurements directly off the temperature controller. This was pretty straight forward, a jig saw or Dremel and a decent file will make the job much easier.

Used the provided plastic attachment pieces to hold the unit once I got the fit correct.

I chose to mount the controller here because this area has a ton of open space once you remove the existing squirrel cage blower. All of our wiring will run to this point.





Finally, Move the capacitor and join the two red wires with some solder. These will both be switched by the cool-side of the ITC-1000. You need to run the neutral (black wire to one side, and the red wires to the other side of the Relay on the ITC).

I simply zip-tied the capacitor the fan-motor mount. Easy.





I also tied a few extra wires to both the hot and neutral using a wire nut for each. This allows us to distribute the power to our ITC-1000 controller, our Wave Maker, and The Relays to enable the fan and compressor. I used a few pieces of scrap copper and a large-gauge wirenut. A small zip tie helps hold these together so you get a positive engagement of the wirenuts.

I also added a few crimp on spades to allow me to attach the necessary hot and neutral wires to the existing capacitor for the compressor and fan, as well as for the lighted switch. Be sure to connect the fan to the right terminal on the capacitor, there are two different values (marked pretty clearly on my unit)





Install the Aquarium Wave-Maker. This is optional, but seemed like a good way to control my glycol bath temperature and improve heat transfer. I ran this to the lighted switch I installed next to my ITC-1000.

Attached to the inside of the bath using the suction cup, with a bit of silicone adhesive so I dont have it floating around in there half-way through a ferment.

While we're in here, why not make the wires neat and run the ITC's temperature sensor using those same mouting squares.





Finally, button it all back up and test it out:







Looks like it'll do the job. Total cost, 100 bucks and a day of fun in the shop. If you want to see it running, I've posted a youtube video of it here- 3 minutes of all of this goodness.

 

Kaze

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Really cool! So how do you get the chilled glycol into the fermenters? An immersion coil in the fermenter with a fountain pump in the glycol?
 
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hunter306

hunter306

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I've got the FTSS2 kits for my conicals, they have a small submersible pump and an immersion coil that comes into the top of the fermenter.

This little project just keeps me from having to keep filling the cooler with ice/dumping the melt.

Cheers!
 

akroessler

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good stuff here man, saw your youtube before i saw this post. What a steal for that AC unit, theyre upwards of 120$ right now. Not sure if i want to wait that long to build mine!
 
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hunter306

hunter306

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Certainly can't beat that price, I was shocked when I found it tucked in the back of the store. Lucky find.

I originally bought it without a project in mind, so it's been sitting, but finally got motivated to tear it apart with the basement getting too warm to cleanly ferment ales the way I like em'

Interestingly, the glycol to load it cost as much as the whole build. I found gallons at the local Tractor Supply USP Grade, for 22.99 a jug. I ended up buying 3 gallons, which I intend to dilute with 7.5g of distilled water. Maiden should be this weekend when I brew up the next batch since one of the kegs in the kegerator just blew yesterday evening.

Cheers from South Lyon. Looks like you're a michigander as well!
 

akroessler

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Luckily all my brew gear is in my basement so it stays around ~60-65 year round down there. I'm looking to make the jump to either a glycol or water chiller, right now i just circulate water from my chest freezer, works perfectly fine and i can lager, but its big bulky and in the way. And i honestly just like the tech side of brewing and fancy gadgets :D. Do you like your conicals? I cant tell if those are the 7 of 14 gal versions. I use the 7 gal brewbucket with FTS and its great, looking to upgrade to their 14g Unitank, especially if i make a build like this.
 
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hunter306

hunter306

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The Unitank sounds awesome, I've got the 7g Chronicals which I just nabbed while ebay was doing the 20% any one purchase promo. I sold my brewbucket to upgrade to these and i'm quite pleased.

I used to do larger 12g batches, but i've since downsized. Keeps things in the 2 tap kegerator rotating on a more frequent basis.
 
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hunter306

hunter306

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Update: Glycol and Distilled Water added to the reservoir this morning, Set the chiller to 30 F and let it chill down.

Ratio: 3gal glycol to 7.5gal Distilled. Perfect volume with the additional equipment in the 52qt cooler.

Chiller reaches 30 and holds temperature very effectively, compressor only runs very occassionally at 70F ambient.

First batch is in, we'll see how it goes!
33367613_10106467102641478_4653415680157155328_o.jpg
 

jaybo

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I'm gonna have to try this! I bought 5 window unit air conditioners when my central air went out in my house, and I still have them. I plan on buying a conical within the next few months, and it would help free up my fermentation chamber for lagering.
 
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hunter306

hunter306

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Definitely worth it, the Window AC was the cheapest part of my build- the cost came in the 70 dollars of glycol (3 gallons) needed for dilution to allow it to chill down below freezing. The rest of the parts were easy to obtain and cheap, I've seen many different builds- mine focused on minimizing the footprint in my small basement area for brewing. The cooler is the perfect reservoir size (52qt) I recommend it for this type of project. It will allow me to expand to more conicals in the future without concern for the capacity of the cooler.

Good luck, here's mine running during the cold-crash phase: https://twitter.com/angryfoxbrewing/status/1006530630421708800
 

Dory Rules

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Regarding converting a window AC to a glycol chiller. I have been thinking of configuring it differently, but I don't know if it is feasible or not. My thoughts are to take off the evaporator, and make a tube in a tube heat exchanger. That way I can have the AC unit separated, connected with hoses. I have a few questions though.
1. Does this even make sense?
2. How long of tubes would be needed (say a 5,000 btu unit)?
3. Would the refrigerant go in the outer tube or inner tube?
 
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hunter306

hunter306

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Hey Dory,

Unfortunately, I'm not very well educated on the compressor side of the AC Unit. I've seen some folks take the stock unit off, create a coiled copper tube which they then immerse, but this moves far beyond my knowledge of refridgeration tech.

The reason I used the bend and pray method with my chiller was to avoid all of that re-engineering. I'm very comfy with the electrical parts... just not those other aspects.

Sorry for the lacking reply!

What I will say is that this unit works awesome. I've run a full batch, including cold crashing and with the configuration I can easily chill to 37 degrees F in my conical. The ice-chest holds temperature of the coolant very efficiently, so if you want to keep things simple- I highly recommend this config.
 

Beachtags

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Regarding converting a window AC to a glycol chiller. I have been thinking of configuring it differently, but I don't know if it is feasible or not. My thoughts are to take off the evaporator, and make a tube in a tube heat exchanger. That way I can have the AC unit separated, connected with hoses. I have a few questions though.
1. Does this even make sense?
2. How long of tubes would be needed (say a 5,000 btu unit)?
3. Would the refrigerant go in the outer tube or inner tube?
To do any of what you are talking about you must be refrigerant certified. While many refrigerants are ozone safe, you are still supposed to recapture them before this lines are cut. Especially the older refrigerants like R-12 and R-22. There are many older Window units and refrigerator/freezers out there still filled with these older refrigerants.

This is just not feezable as a DIY without being an AC/refrigerant technician. But if you know someone with the equipment and time to spare..... Refrigerant lines are under really high pressures .. And the copper is brazed together not soldered.
 

perogi

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Sorry to resurrect an old post but this one helped me quite a bit - thank you!

Wondering if you have some measurements for that sled. I created my set up to mimic yours so any info is greatly appreciated.
 
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hunter306

hunter306

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Sled is 19" x 27" external dimension, 18" x 26" top dimension (after routing)

The Riser Box is roughly 4.8" tallk, to make the top of the AC Unit flush with the top of the cooler lip (with lid open).

With the wheels on the cooler removed, you should simply measure the space you need between the two uprights on the cooler retention bracket to make sure it doesn't fall off while moving (mostly, to keep it from stressing the condensor).

Sorry for the late reply!
 

breweer

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Sorry if I overlooked it, but is the BTU of the AC unit you used in this build?
 

noelb

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Sorry, new to the forum. Great build, however I am not super comfy with the wiring. Could a guy just use and inkbird ITC 308 with the temp probe in the glycol?
 

MrWalli3

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Can anyone see the pictures that he posted...just shows them x’ed out was going to start my chiller build and use this has a reference.
 
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hunter306

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IMG_7344 (2).jpg


Nope, the website that they were hosted at was unfortunately taken down. Sorry about that.

I attached an overview picture that shows the design cracked open above.

As well as how the wires were oriented below, hopefully that helps. The STC should simply be controlling the compressor and fan through the high-speed wire from your original manual controls. Pretty straight forward if you draw a simple diagram as you disassemble. For the other fan speeds, you'll likely be isolating that wire completely as they won't be used for this design.

IMG_7367.jpg
 

perogi

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Love the build. Looks super sleek.
Have you used this to simultaneously cold crash both Chronicals? Deciding between building this or ponying up and purchasing a legit one.
I just did both of my 15 gal conicals with no issues at all. My basement was in the high 50s so cooler than normal but the AC unit was nowhere near overworked so I'm confident that it would work at a much higher ambient.
 

perogi

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Sorry, new to the forum. Great build, however I am not super comfy with the wiring. Could a guy just use and inkbird ITC 308 with the temp probe in the glycol?
If you get a manual AC unit, the wiring will be much easier than an electronic one to bypass the AC power button. I do use an inkbird to turn the AC unit off and on though so you don't need the one that he's using above although his solution is much cleaner.
 

Summoner12

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You have a great post here. I like how clean you made it. Thanks for sharing!

I am researching coolers because I need to cool a beer trunk line. This is more rhetorical, but I am wondering if my unit, or a unit like yours has the power to maintain my trunkline.... hmmmm
 

Grant Detrick

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Is it necessary to add anything to the glycol/water bath to keep it from going bad? Or does the glycol inhibit the growth of anything nasty? Given the cost of the glycol, I do not want to risk having to dump the mixture at some point down the road. Thanks in advance.
 

juan_cantavella

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View attachment 615847

Nope, the website that they were hosted at was unfortunately taken down. Sorry about that.

I attached an overview picture that shows the design cracked open above.

As well as how the wires were oriented below, hopefully that helps. The STC should simply be controlling the compressor and fan through the high-speed wire from your original manual controls. Pretty straight forward if you draw a simple diagram as you disassemble. For the other fan speeds, you'll likely be isolating that wire completely as they won't be used for this design.

View attachment 615848
Brilliant design thank you!
 
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It is hard to follow which wires you are talking about above without the pictures. I think I might possibly have different color wiring? This is a 5000 btu Frigidaire as well. I have gone too far to pull back now! haha. Could you tell me a little about which wires go where from this pic?
 

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