My son ripped apart a small water cooler and made a kegerator.
here is the compressor and the coils the little white thing is the cooler unit that gets submerged in the glycol.
this is the unit with the coolant lines straightened out and feed through the cutout that goes to the cabinet. Its installed in a portable bar the thermostat is in the upper right hand corner
Three gallon keg in a small wastepaper basket .Filled with RV anti freeze Foam top is missing
We put some spray foam on the outside since the pic was taken . Plan is to upgrade to a beverage type cooler as soon as he finds a used one. The whole setup cost him 10$ . I gave him the keg, lines ,fitting and the Perlick tap for his birthday.
and of course the tap
This works surprisingly well it runs for 6-10 minutes every two to three hours and maintains 40° with no mods to the thermostat. You do have to cool the keg before putting it into the cold glycol.