It hasn’t even been 10 years since there was a panic that the CFC ban would force everyone to replace their R-11 and R-12 chillers quickly because the refrigerants simply weren’t going to be available. That didn’t happen, of course (although the prices have certainly gone up), but some good things came from that concern.
Basically, some started looking at what takes place during a chiller retrofit. And it was found that not much happened other than the old chiller was taken out and a new one of the same size was put back in. A valuable concept emerged from this examination: if a chiller has to be replaced anyway, it should be done in the most cost-effective and energy-efficient manner possible. That included looking at the whole building as a system when any changes were made to the space conditioning equipment.