Ammonia refrigeration technology predates the freon systems we use in our stick houses. Because the ammonia systems need a significantly small heat source to work they are more efficient, especially when electricity is a valuable commodity. Now that big coaches have vary large battery banks and really big, efficient diesel engines turning big alternators, electrical power is plentiful and household type (freon) refrigerators are practical.
The problem(s) has to do with camping off the grid with a minimum amount of electrical power. In that situation, the ammonia systems work best.
