Thank you MrFreez, for your answer!

If I understand correctly you did system witch CO2 on the second stage. My design is quite different, I'm going to use R23+R14 blend (R14 to go below -80 celsius without using 3rd stage). Currently I expect operating high pressure to be up to 21 barg (305 psig). So giving 20% buffer my Desing pressure should not be lower than 25.2 barg (366 psig). The system is also designed as a "limited charge system", I have a buffer tank to store evaporated refrigerant while the system is turned off, so there is no need for extra chillers to keep it liquefied.

I would like to not exceed 400psig design pressure. Most UL and ASME certified components which are available in Europe have 400pisg rating. Importing components from US takes a lot of time and usually cost a lot.

Does my system design sounds good to you and I can stay with 400psig design pressure?

Thanks,
Adrian