DIY Inexpensive Chiller

I was holding off on posting this until I actually did it and could provide a detailed walkthrough with pictures,

But thats not happenin anytime soon (whatup israel)

So you can turn a dehumidifier or an AC unit into a simple chiller for a fraction of the price of a new one.

Go buy the nicest Dehumidifier you can find at your local hardware store. Pull the faceplate and covers off and youll see 2 heat exchangers back to back. Dont touch the Heat exchanger thats touching the fan.

Bend the second heat exchanger down and to the back/side of the dehumidifier. Be very careful to not kink the Copper refrigeration tubes or youll break the unit.

Get a insulated cooler, and drop that second heat exchanger into it… itll take some careful placement to get it submerged properly.

Fill the Cooler with Antifreeze, throw an aquarium pump into it, attach tubes to whatever system you need chilled, and viola!! 2000 dollar chiller value for 500!

When I get home ill get around to doing this for a friend and ill post good pics

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You can also find used chillers on ebay that work fine. Found one for $700 that can run 2x5L rotos.

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A chiller is ONLY needed when your required temps are below ambient temperatures. All the chiller does is take the heat and concentrate it so that it can dump it out into the surrounding environment. There lot’s of ways to do this without a refrigeration systems if your required cooling temps are above ambient.
A dehumidifier is not ideal but the same idea can be found with cooling towers. They have some for cooling pools that would be very efficient and scalable.
If you have a cool water source you can dump the heat into that using a liquid to liquid cooler see here Notice how much heat it can remove
If you just want to dump into the air you could use a diy radiator style cooler or could get a nice one here

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An aquarium chiller used on eBay would be good too. You can find 1hp units pretty cheap and most will run as low as 0c

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walked in on a neighbor who was building a super critical CO2 rig about a year ago, just as he was dissecting a $100 Wally World window AC unit to make a chiller. I knew it was fairly simple but seeing it done was helpful.

if you just happen to have a refrigerant recovery pump and vacuum pump lying around, you can even pull the refrigerant out, mod the plumbing, and recharge with the refrigerant you pulled on step one…rather than risk losing the refrigerant and having to go buy more.

Edit: I guess you could upgrade to R600 or R290 if you have that on hand :wink:

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I’ve got a few old ac units and dehumidifiers not in use. I was going to build a DIY chiller out of one. The first one I poped open has a bunch of rust. Should I move on to the next one, or try to clean up as much rust as possible and use it?

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You could at least salvage sum stuff from it @blackie.guess it depends on its final purpose…

We should start learning to make cascade systems with 134a, and a stage of bbq propane. Where’s all the hvac engineers at? I have a few cascading systems… maybe I’ll post pix of the guts…

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I was planning on making a glycol chiller for a 5l rotovap, hopefully using stuff I already have on hand. Looks like the cooler I have is 45 liter capacity.

I’d be interested in trying to make something that can get down to really cold temperatures at some point in the future.

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in case you missed this thread…

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A couple of tips from years of making ac glycol chillers for reef aquariums and overclocking pc’s.

Use the biggest ac you have on hand. Dehueys operate under a different criteria than raw heat removal. They work ok and better than a freezer refrigeration system but they are typically lower btu rating than comparable amperage window units.

Use a cooler as the reservoir to help keep the heat load down. Insulate the tubing lines to your roto condenser. 8000 btu is roughly equivalent to a 1hp chiller this was taken from a beer forum but there are quite a few variables at at play here that make it not so comparable. There’s a thread on here with more in depth information on building glycol chillers

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That looks like a bent coil is that the outdoor unit of a central ac?

I did see that thread. The fluid is more expensive than I thought it would be, that why I am wondering about using the rusty one. I should probably check all the ones I have and pick the best one…not the first one I pop open. Hopefully they aren’t all that rusty.

Was Lucky rusty?

It’s a portable ac unit. I was hoping to use the 6” vent so I could exhaust hot air in the summer.

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@Rowan build

Glycol chiller with dry ice assist reservoir

More diy chiller info

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Yeah that will work fine. drop the cold side in a reservoir, fill rese with automotive glycol, recirculate.

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Got a make and model number?

Any way you could post more detailed instructions, I’ve never really worked with taking apart AC’s or other HVAC gear, worked with lots of other stuff though. This looks like you might know how to do it from start to finish

Are you just looking to use a window unit to make a chiller?

If so, it’s pretty easy and there’s a ton of information already out there.

Google diy ac chiller and there’s tons of vids and walk throughs already.

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i have been, its fairly vague like these instructions