I’m looking to convert my icebox on a recent vintage 34-foot boat to a refrigerator. I have already improved the insulation around the icebox. I currently have a heat exchanger unit installed (by previous owner) but it’s not up to the job. Does anyone out there in cyberspace have any cheap alternative i.e. possibly retrofitting a domestic refrigeration unit to fit my needs. The off the shelf units are in the $700-800 price range and I need that money for beer to put in the fridge.