DIY Inexpensive Chiller

[cyclopath]

in case you missed this thread…

Suggestions for diy glycol chiller fluid?

Most threads on here discussing chiller fluids are in the context of hardware being used. Im making my own diy glycol chiller with an old 25k btu window ac. The reservoir is going to be a 55 gallon barrel. Trying to decide the best fluid to use. Found 50/50 green antifreeze but working on getting the actual specs to see if it can handle -20c. Also found barrels of glycol for around 500. So I’m wondering if there’s any suggestions for my application. Needs a to be non corrosive to not destroy the…