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I made this back over the summer, not exactly for beer brewing, but it could be used for that purpose with zero modifications. I made it to support my racing habit and tendency to overheat. In the summer we wear cool shirts under our nomex to keep cool in the race car. The shirts have tubes run all over them, and you pump ice water through to keep cool. In the car we have just a big cooler filled with ice water and a bilge pump. I wanted a unit for the pits so that after you climb out of the car you can cool down further (or just sit plugged in if it's 90+ degree out).
So, here's how it's built. The whole thing was fairly cheap and works flawlessly.
Things you'll need:
- Window AC. Does not need to be a large one, in fact small is good. I found a small one on craigslist for $40
- Cooler. Pick out the cheapest one you can find that will fit all your stuff inside
- Bilge pump or some other submersible pump I used this one
- Circulation pump. It's good to have something to keep the liquid moving through the fins and keep them freezing. I used this aquarium pump.
- Temp Controller. Any basic controller will work, I used this one
- AC to DC converter to run the 12V pump (omit if you pick a 110V AC submersible pump). I used this one.
- SSR for switching the window AC on and off
- enclosure for the controls
- Misc wire, connectors, etc
- Silicone sealant for resealing the cooler
- A board to mount it all on.
So building this thing. Start by taking the AC unit apart. Pull the cover, get it down to the basic base, refrigeration system, and motors. The radiator we care about is the cool side, the one that your room air blows across. In this picture it's the one at the front of the work bench with the Styrofoam behind it. This is the part we need to submerge in water.
I don't have pictures of all the steps, but you'll need to remove the fan that circulates air and blows it back into the room. You'll likely need to cut the shaft that drives that as well. Then pull all the styrofoam out. Next you'll need to very carefully cut back the base of the AC unit. You'll need it back far enough that the window AC can sit next to the cooler with the coil sitting inside it. The coil will be free floating at this point, which is ok.
Pull the lid off the cooler, and then mark the location that the pipes leading to and from the coil will line up with the cooler. Grab a cutting instrument and cut a slot down the cooler deep enough to slide those hoses into. Save the plastic bits, we'll need them to reseal everything. Here you can see the cut cooler with the coil sitting inside. You'll need to lift the AC and lower it into place like this.
I ran the AC briefly just to see what this coil gets to temp wise. It hit -4F in just a couple minutes and the whole cold side started frosting over. Tons of cooling power here, probably way more than we need.
Now is the time to figure out your main base. You want to firmly mount both the AC and cooler so that neither can move. I picked a piece of 3/4" plywood that was about the right size. Mark and drill a few holes through the cooler, then use a mix of long bolts, fender washers, and self locking T-nuts Like these to secure it. Make sure to use silicone between all layers of fasteners to prevent leaks in the cooler. Do the same to secure the AC base to the plywood minus the silicone.
Here you can see I trimmed the AC cover back so I could reinstall it and protect the system.
With everything mounted you need to seal the cooler. Take your saved plastic, tape it back into place so that it's firmly held. Then inject the whole void with expanding foam. I used generic great stuff. Let that fully cure, cut off any extra that spills out. Then go back and liberally cover all the seams with silicone sealant. you can see this in the next picture below.
Inside the cooler. Now you need to add in all the parts to your cooler. Point the re-circulation pump right at the coil. Find a home for your pump. If you're trying to feed more than one item buy the appropriate fittings to build up a manifold for dividing the pump output. You can see I have it splitting to at least 3 feeds, and then have 3 return hoses coming through the cooler lid. Run the power wires for both pumps, and he temp sensor for the controller through a hole in the cooler and seal up with silicone.
Pump tests. I needed more water in the cooler than this.
The controller. I stuffed the controller, SSR (with heatsink), and AC to DC power supply in a small project box. As far as wiring. If you're scared to touch the AC internals, don't. Just strip the plug off the main power chord, and run it off the SSR to turn on and off. Let the brains keep working. I went a step further, removed most of the brains, wired it so that the hot side fan would always be on at medium speed, and wired the compressor to the SSR with it's start capacitor. I don't have a diagram unfortunately. Each AC is different honestly, so you'll need to study it's wiring diagram and figure out the unit you own.
Make sure you've got a good ground connection to all major components. And for maximum safety consider using a GFCI power chord to run the whole thing. I did add two switches to turn the circulation pump and bilge pump on and off after this picture was taken.
This is the completed unit with the control box on the side. I tested and it brought the cooler down to ~38°F in about 10 minutes from a starting point of ~70. I programmed it so that it will keep the compressor off for a minimum of a minute before ever starting it again to prevent damage. It holds the cooler water to +/- 1°F with zero issues at all. For race weekend we set it to 36°F and ran just straight water, but you could easily add some gycol or other chemicals and run it at sub 32°F
So, here's how it's built. The whole thing was fairly cheap and works flawlessly.
Things you'll need:
- Window AC. Does not need to be a large one, in fact small is good. I found a small one on craigslist for $40
- Cooler. Pick out the cheapest one you can find that will fit all your stuff inside
- Bilge pump or some other submersible pump I used this one
- Circulation pump. It's good to have something to keep the liquid moving through the fins and keep them freezing. I used this aquarium pump.
- Temp Controller. Any basic controller will work, I used this one
- AC to DC converter to run the 12V pump (omit if you pick a 110V AC submersible pump). I used this one.
- SSR for switching the window AC on and off
- enclosure for the controls
- Misc wire, connectors, etc
- Silicone sealant for resealing the cooler
- A board to mount it all on.
So building this thing. Start by taking the AC unit apart. Pull the cover, get it down to the basic base, refrigeration system, and motors. The radiator we care about is the cool side, the one that your room air blows across. In this picture it's the one at the front of the work bench with the Styrofoam behind it. This is the part we need to submerge in water.
I don't have pictures of all the steps, but you'll need to remove the fan that circulates air and blows it back into the room. You'll likely need to cut the shaft that drives that as well. Then pull all the styrofoam out. Next you'll need to very carefully cut back the base of the AC unit. You'll need it back far enough that the window AC can sit next to the cooler with the coil sitting inside it. The coil will be free floating at this point, which is ok.
Pull the lid off the cooler, and then mark the location that the pipes leading to and from the coil will line up with the cooler. Grab a cutting instrument and cut a slot down the cooler deep enough to slide those hoses into. Save the plastic bits, we'll need them to reseal everything. Here you can see the cut cooler with the coil sitting inside. You'll need to lift the AC and lower it into place like this.
I ran the AC briefly just to see what this coil gets to temp wise. It hit -4F in just a couple minutes and the whole cold side started frosting over. Tons of cooling power here, probably way more than we need.
Now is the time to figure out your main base. You want to firmly mount both the AC and cooler so that neither can move. I picked a piece of 3/4" plywood that was about the right size. Mark and drill a few holes through the cooler, then use a mix of long bolts, fender washers, and self locking T-nuts Like these to secure it. Make sure to use silicone between all layers of fasteners to prevent leaks in the cooler. Do the same to secure the AC base to the plywood minus the silicone.
Here you can see I trimmed the AC cover back so I could reinstall it and protect the system.
With everything mounted you need to seal the cooler. Take your saved plastic, tape it back into place so that it's firmly held. Then inject the whole void with expanding foam. I used generic great stuff. Let that fully cure, cut off any extra that spills out. Then go back and liberally cover all the seams with silicone sealant. you can see this in the next picture below.
Inside the cooler. Now you need to add in all the parts to your cooler. Point the re-circulation pump right at the coil. Find a home for your pump. If you're trying to feed more than one item buy the appropriate fittings to build up a manifold for dividing the pump output. You can see I have it splitting to at least 3 feeds, and then have 3 return hoses coming through the cooler lid. Run the power wires for both pumps, and he temp sensor for the controller through a hole in the cooler and seal up with silicone.
Pump tests. I needed more water in the cooler than this.
The controller. I stuffed the controller, SSR (with heatsink), and AC to DC power supply in a small project box. As far as wiring. If you're scared to touch the AC internals, don't. Just strip the plug off the main power chord, and run it off the SSR to turn on and off. Let the brains keep working. I went a step further, removed most of the brains, wired it so that the hot side fan would always be on at medium speed, and wired the compressor to the SSR with it's start capacitor. I don't have a diagram unfortunately. Each AC is different honestly, so you'll need to study it's wiring diagram and figure out the unit you own.
Make sure you've got a good ground connection to all major components. And for maximum safety consider using a GFCI power chord to run the whole thing. I did add two switches to turn the circulation pump and bilge pump on and off after this picture was taken.
This is the completed unit with the control box on the side. I tested and it brought the cooler down to ~38°F in about 10 minutes from a starting point of ~70. I programmed it so that it will keep the compressor off for a minimum of a minute before ever starting it again to prevent damage. It holds the cooler water to +/- 1°F with zero issues at all. For race weekend we set it to 36°F and ran just straight water, but you could easily add some gycol or other chemicals and run it at sub 32°F
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