Rotary compressor a good choice in VRF?

[K.R.Iyer]

I think this topic needs a separate thread for more clarity to evolve for me.

The rotary compressors used in the small capacity Room Acs have less life compared to a recip or scroll compressor. I wonder if a rotary can be a reliable choice - purely on reliability front - in a VRF where the charge qty is very high, the tubing lengths are long, chances of contamination from tubes are more etc. It will be interesting to hear from people who have handled both rotary inverters and scroll inverters. Thanks!

[mekaniko5]

Rotary compressors are vulnerable to liquid refrigerant and as you have pointed out, VRF systems require a large amount of refrigerant charge.

Since rotaries have limited protection against liquid unlike scroll compressors such as from Copeland Brand; suction accumulators, solenoids and liquid bypass pipes, are added to serve as the rotaries protection. In my opinion, when you have more parts you’ll end up with more piping runs and valves which may lead to leakage.

Also, rotaries tend to have smaller capacities that most scrolls. This means 2 rotary compressors are needed for larger capacity VRF system. If you have 2 rotaries, the system would require more solenoids, liquid bypass, and bigger tanks.

[K.R.Iyer]

Mekaniko5,
Thanks for your comments, but seems to be one-sided. Quite a few big brands use Inverter driven rotary in place of inverter scrolls....

[aris285]

I have worked with screw compressors up to 100HP and do not have no problem from them….