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


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



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


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


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: