COmpressor Selection for AutoCasacde

[ssk7899]

Dear Sir , I am new to Forum, Could anyone help me in
Design for 20TR at -40degc and 10TR at -70degc .
Can i go for Auto cascade Sytem or Cascade Sytem
What refrigerant should i use.
Capacity for Condenser,Evaporater,Phase Separator.etc

[D.D.KORANNE]

1) low side refrigerant r-23 for -70 sst
2) high side can be r-404a or r-22
-40 deg c sst . But what about high side condensing temp ? Aircooled or water cooled ?

[ssk7899]

Dear Koranne thanks for reply..
Its air cooled design ..
Condensing 50degc