Centrifugal compressor with liquid injection

A two stage chiller comprising:

• a first stage centrifugal compressor including
• a first impeller rotatable about a first rotation axis, and
• a first diffuser disposed in a first outlet portion downstream from the first impeller, the first diffuser having a first upstream edge and a first downstream edge;
• a second stage centrifugal compressor including
• a second impeller rotatable about a second rotation axis, and
• a second diffuser disposed downstream from the second impeller, the second diffuser having a second upstream edge and a second downstream edge;
• at least one motor arranged and configured to rotate the first impeller and the second impeller;
• a return channel flow path connecting the first diffuser to the second impeller;
• a condenser;
• an economizer;
• an evaporator connected in series with the first stage centrifugal compressor, the second stage centrifugal compressor, the condenser, and the economizer;
• a plurality of injection ports located circumferentially around the second diffuser and the first diffuser;
• and
• at least one injection passage connected to the plurality of injection ports, the at least one injection passage being arranged and configured to deliver liquid refrigerant from the economizer,
• the second diffuser having a second inlet side and a second outlet side, the second outlet side being downstream of the second inlet side, and
• the plurality of injection ports being disposed in the second outlet side of the second diffuser.

A two stage chiller comprising:

• a first centrifugal compressor including
• a first impeller rotatable about a first rotation axis, and
• a first diffuser disposed downstream from the first impeller;
• a second centrifugal compressor including
• a second impeller rotatable about a second rotation axis, and
• a second diffuser disposed downstream from the second impeller;
• at least one motor arranged and configured to rotate the first impeller and the second impeller;
• a condenser;
• an economizer;
• an evaporator connected in series with the first stage centrifugal compressor, the second stage centrifugal compressor, the condenser, and the economizer;
• a plurality of injection ports circumferentially arranged around at least one of the first diffuser and the second diffuser;
• and
• at least one injection passage connected to the plurality of injection ports, the at least one injection passage being arranged and configured to deliver liquid refrigerant from the economizer,
• the second diffuser having a second inlet side and a second outlet side, the second outlet side being downstream of the second inlet side, and
• the plurality of injection ports being disposed in the second outlet side of the second diffuser.