A really tight COMPRESSOR ice plant prefers ammonia. I read some "comments" that ammonia is 3-10% more efficient than freon. Fascinating. When one company on the coast ditched a freon-12 system for a chipped ice plant in favor of ammonia, the owner showed me his electric bills. -22% on average.
Wouldn't it be nice IF, ammonia equipment could endure many tens of thousands of continuous operation leak-free?
Not having a decent understanding of HVAC, I am wondering how ammonia would stack up for duty in an A/C unit? The secret of course is maintaining a leak-free system. The efficiency is tantalizing.