View Full Version : "SPECIAL" screw compressor

06-11-2010, 08:07 AM
Have a process application which would run under following conditions .

NH3 Economized VSD -33 C SST
+ 48 C SDT

Apart from possible higher pressure rated casting would anything else have to be "SPECIAL" about it ?

Anyone have experience ?

06-11-2010, 10:05 AM
Why not a normal cascade system with NH3 on the low stage, and some other natural refrigerant on the high stage?

06-11-2010, 05:13 PM

22-11-2010, 11:35 PM
Air cooled on R-717 is comparable to these conditions; considerable data on that in the IIAR technical sessions. Also more recently on using R-717 in central heat pump arrangements. Check the Vilter web site; they did nice work on a "small channel" single rotor screw for such purposes; high side to 85-deg C condensing.


24-11-2010, 06:48 PM
Limits on Vilter standard Single Screws are MAWP above 33 bar and pressure ratio 20:1.
This application is within the limits, no need for their special high pressure compressors (MAWP 75 bar).