There are direct replacements and refrigerants that require different equipment. And different refrigerants for different purposes. So all that amounts to a pil

There are direct replacements and refrigerants that require different equipment. And different refrigerants for different purposes. So all that amounts to a pile of really bad refrigerants (cfcs), newer refrigerants (high GWP), and the newest refrigerants (low GWP) with a half dozen or so varieties for each.