Hvac compressor with mixed and radial compression stages

Abstract

A refrigerant compressor according to an exemplary aspect of the present disclosure includes, among other things, a first compression stage arranged in a main refrigerant flow path. The first compression stage is a mixed compression stage having both axial and radial components. The compressor further includes a second compression stage arranged in the main refrigerant flow path downstream of the first compression stage. The second compression stage is a radial compression stage.

1 . A refrigerant compressor, comprising:
 a first compression stage arranged in a main refrigerant flow path, wherein the first compression stage is a mixed compression stage having both axial and radial components; and   a second compression stage arranged in the main refrigerant flow path downstream of the first compression stage, wherein the second compression stage is a radial compression stage.   
     
     
         2 . The refrigerant compressor as recited in  claim 1 , wherein the first compression stage is arranged such that fluid is configured to flow therethrough along a direction inclined relative to an axis of rotation of the refrigerant compressor. 
     
     
         3 . The refrigerant compressor as recited in  claim 2 , wherein the direction is inclined at an angle of less than 45° relative to the axis of rotation of the refrigerant compressor. 
     
     
         4 . The refrigerant compressor as recited in  claim 1 , wherein:
 the main refrigerant flow path is defined between an outer wall and an inner wall,   adjacent an inlet of the first compression stage, the outer wall and inner wall are radially spaced-apart from one another by a first radial distance, and   adjacent an outlet of the first compression stage, the outer wall and inner wall are radially spaced-apart from one another by a second radial distance less than the first radial distance.   
     
     
         5 . The refrigerant compressor as recited in  claim 4 , wherein the outer wall and the inner wall are curved within the first compression stage. 
     
     
         6 . The refrigerant compressor as recited in  claim 5 , wherein, within the first compression stage, the outer wall and the inner wall are concave when viewed from a radially outer location. 
     
     
         7 . The refrigerant compressor as recited in  claim 5 , wherein the outer wall and the inner wall have inflection points and smoothly transition such that the outer wall and the inner wall are substantially parallel to one another between the first compression stage and the second compression stage. 
     
     
         8 . The refrigerant compressor as recited in  claim 7 , wherein an array of static diffuser vanes is arranged in the main refrigerant flow path between the first compression stage and the second compression stage. 
     
     
         9 . The refrigerant compressor as recited in  claim 1 , wherein the second compression stage includes an impeller configured to turn a substantial axial flow to a substantial radial flow. 
     
     
         10 . The refrigerant compressor as recited in  claim 1 , wherein the main refrigerant flow path makes a substantially 180 degree turn between the first and second compression stages. 
     
     
         11 . The refrigerant compressor as recited in  claim 10 , wherein the main refrigerant flow path includes a cross-over bend between the first and second compression stages. 
     
     
         12 . The refrigerant compressor as recited in  claim 11 , wherein deswirl vanes are arranged within the main refrigerant flow path downstream of the cross-over bend and upstream of the second compression stage. 
     
     
         13 . The refrigerant compressor as recited in  claim 1 , wherein the refrigerant compressor is used in a heating, ventilation, and air conditioning (HVAC) chiller system. 
     
     
         14 . A refrigerant system comprising:
 a main refrigerant loop including a compressor, a condenser, an evaporator, and an expansion device, wherein the compressor includes:
 a first compression stage arranged in a main refrigerant flow path, wherein the first compression stage is a mixed compression stage having both axial and radial components; and 
 a second compression stage arranged in the main refrigerant flow path downstream of the first compression stage, wherein the second compression stage is a radial compression stage. 
   
     
     
         15 . The refrigerant system as recited in  claim 14 , wherein the first compression stage is arranged such that fluid is configured to flow therethrough along a direction inclined relative to an axis of rotation of the refrigerant compressor at an angle of less than 45° relative to the axis of rotation of the refrigerant compressor. 
     
     
         16 . The refrigerant system as recited in  claim 14 , wherein:
 the main refrigerant flow path is defined between an outer wall and an inner wall, and   the outer wall and the inner wall are curved within the first compression stage such that the outer wall and inner wall are concave when viewed from a radially outer location.   
     
     
         17 . The refrigerant system as recited in  claim 14 , wherein an array of static diffuser vanes is arranged in the main refrigerant flow path between the first compression stage and the second compression stage. 
     
     
         18 . The refrigerant system as recited in  claim 14 , wherein the second compression stage includes an impeller configured to turn a substantial axial flow to a substantial radial flow. 
     
     
         19 . The refrigerant system as recited in  claim 14 , wherein the main refrigerant flow path makes a substantially 180 degree turn between the first and second compression stages. 
     
     
         20 . The refrigerant system as recited in  claim 14 , wherein the refrigerant system is a heating, ventilation, and air conditioning (HVAC) chiller system.