The reason those took off so well is cause Freon, while awful for ozone, is significantly safer than the previous usage of ammonia.

Refrigerators and air conditioners just compress a gas into a liquid, moves it through piping, and then decompresses the gas. When compressing the gas (a refrigerant), it'll want to turn liquid, but has to burn off heaps of excess energy, done as heat energy. That's done in the part of an AC unit that hangs outside. The liquid is then pumped to the other side of the machine, relieved of pressure, and sent through tons of piping with heat grates and fans for dissipating the cold air it generates. When evaporating from liquid to gas it needs to take in heaps of energy, so it'll draw heat from the air, cooling it. The gas is pumped back to the compressor on the other side of the unit to repeat the process over and over. Propane is really good at being compressed like that, and it has minimal effect on global warming, so it can be used as a freon alternative. Just yanno, don't use it in your car's AC.