Sounds fascinating but Ammonia is not the most user-friendly substance, is it?
I remember a movie with Harrison Ford in it, where he builds a refrigeration plant in S America. It blew up spectacularly. That is just about my knowledge on the subject. Ammonia is not stable enough, to be used widely.
You will definitely notice if you have a leak.
If ammonia spills it won’t cause damage to plant life. In fact it will work as fertilizer.
There won’t be a fire risk if it spills.
No, it’s not. It is produced when coking coal; a process the greens hate but is critical for steelmaking. Or, ammonia can be produced by the Haber-Bosch process, which is in widespread use, primarily for making fertilizers. The “fixing” of nitrogen (getting nitrogen to combine chemically with other substances which is very difficult as nitrogen is generally quite inert) was considered one of the greatest chemical problems/advances and was solved in the early 1900’s. Most chemists would opine that being able to create ammonia (and thus fertilizers) from atmospheric nitrogen is responsible for the existence of half or more of the world’s population.