refrigerant flow 14 is urged to a condenser 16 where the refrigerant flow 14 is condensed into a liquid state the refrigerant flow 14 is rapidly depressurized in an expansion valve 18 which reduces the temperature of the refrigerant flow 14 the cooled refrigerant flow 14 is then routed to an evaporator 20 where it is evaporated and absorbs heat from a fluid flowing across the evaporator 20 by for example air as propelled by a fan 22 fig2 illustrates an embodiment of the compressor 12 the compressor 12 includes two compressor impellers a first impeller 24 and a second impeller 26 axially secured to a shaft 28 in some embodiments the first compressor impeller 24 and or the second compressor impeller 26 are centrifugal rotors in the embodiment of fig2 the first compressor impeller 24 and the second compressor impeller 26 are disposed at substantially opposing ends of the shaft 28 for improved rotor dynamic characteristics it is to be appreciated that other configurations for example ones where the first impeller 24 and second impeller 26 are disposed substantially adjacent on the shaft 28 are contemplated within the scope of the present disclosure further while the quantity of compressor impellers illustrated in fig2 is two it is merely used as an example and other quantities of compressor impellers for example 1 3 or 4 or more compressor impellers may be utilized the compressor impellers 24 and 26 are disposed in a housing set 30 which in some embodiments comprises a first housing.