what works really well is a carbonator pump and a Heater core and fan with a 3 gal tank pretty much is exactly what Lincoln uses on there Precision tig units for there chiller
the pump can be had on ebay same with the motor to run it
the heater core any parts house
110v fan
the tank make one or get it from a restaurant supply house and make cover for it
i am pretty sure there is a reason they(the major manufactures) use this setup and have been for over 30 plus years
Lincoln precision tig 275
Miller Syncrowave 350 Tig
Miller 250 Mig
old miller 200 Mig
HF 151 Mig
HF 100 FC
Victor Journeyman Oxy/Ace set up
Bunch of tools of the trade to much to list