likely to kill you outright. This isn't household ammonia solution, it's anhydrous vapor. Very nasty...
My father-in-law has largely monocular vision due to an NH3 incident some years ago. It's corrosive and poisonous, and has no place in a mobile environment. It eats copper, and is used with a 100% steel plumbing system, I doubt any modern aluminum evaporator or condensor could be used. I don't know if there are any flexible hoses that can take it. I'm not sure which (if any) lubricants are compatible with it, so you'd need a York-style compressor not one of the modern radial/axial types. I suppose with a frame-mounted ancient compressor and a sufficiently flexible belt-drive system, and custom all-steel lines, fittings, and finned devices you could do it. But then I'd be worried about metal fatigue. The amount of NH3 in the RV absorbtion refrigerator is actually pretty small. They are also stunningly ineffective (though I can't speak for the efficiency) in that the heat-transfer capacity is very small. They can take hours to cool down to operating temperature. That cycle is useless for comfort uses, you'd need the heat pump type of cycle, and that takes a lot more working fluid. Old (pre-war) refrigeration books make interesting reading. The advent of Freon (et al.) totally killed the market for ammonia, hydrogen sulfide, and carbon tet consumer goods! -- Jim
