I'm starting to work on a new build for computer cooling, three stage cascade.
R507a, r1150, r14+r740 (with subcooler)
Aims for -125C or colder.
Right now looking to use a TXV on first and 2nd stages. The first two compressors are 3/4hp tecumseh rotarys, while the third is a 1.125hp tecumseh rotary compressor.
What sort of TXV should I use for working with something like liquid ethylene, which will be around -30 to -40C into the TXV, and -80 to -100C outlet from the TXV into the second plate heat exchanger.
Or should I just swap to capillary?