In article , Bruce L. Bergman
writes:

Reality check: R-11 or R-12? They use R-11 in huge centrifugal
compressor chiller systems like that, and R-12 in automotive systems.

I read that far and went "what's wrong with that statement?..."


That was a long time ago but It seems that they were using R-12 because it was
cheaper and it operated at a lower temp. which meant tha the heat transfer rate
would be greater.
Engineman1