Crunching number on a R-507 – CO2 cascade system. I am showing there may be a potential installed costs advantage. The old school’ers are telling me to stop due to the higher pressures of the CO2 side. But if I design the CO2 side with CO2 rated components and compressors, rather than standards components for ammonia or halocarbons, what’s the big deal? What is with the high pressure scare, that make everyone not even consider this?

What am I missing?