Abstract: A centrifugal compressor according to an exemplary aspect of the present disclosure includes, among other things, an impeller provided in a main flow path and configured to pressurize a main flow of fluid. The compressor also includes a secondary flow path configured to provide a secondary flow by recirculating a portion of the main flow. The amount of the main flow that becomes the secondary flow is less than or equal to 15%. A method is also disclosed.

Abstract: A compressor system having a centrifugal compressor, controller and an interface is disclosed. The compressor includes adjustable guide vanes and a variable geometry diffuser. The controller is in electrical communication with each of the guide vanes and diffuser so as to monitor and adjust positions thereof in accordance with a predetermined control algorithm. The control algorithm is implemented in accordance with a method of controlling the centrifugal compressor. The method adjusts the position of the diffuser based on the actual lift, guide vane position and predetermined relationships between diffuser position and reference lift.

Abstract: A centrifugal compressor according to an exemplary aspect of the present disclosure includes, among other things, an impeller provided in a main flow path and configured to pressurize a main flow of fluid. The compressor also includes a secondary flow path configured to provide a secondary flow by recirculating a portion of the main flow. The amount of the main flow that becomes the secondary flow is less than or equal to 15%. A method is also disclosed.

Abstract: A centrifugal compressor includes a housing providing in inlet, an impeller, a diffuser and a volute or collector. An electric motor is provided in the housing and is configured to drive at least one impeller via a shaft about an axis. The impeller includes an outlet end aligned with a diffuser and arranged at the throat. A variable fluid injector device is arranged downstream from the outlet end of the impeller in one example. The variable fluid injector device is configured to introduce high pressure fluid downstream from the impeller in response to a compressor regulation command. The injected fluid energizes the low momentum boundary layer, which provides compressor stability. A compressor controller is in communication with the variable fluid injection device to obtain a desired compressor operating condition.

Abstract: This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

Abstract: A refrigeration system includes a chiller having a refrigerant loop. A compressor is part of and in fluid communication with the refrigerant loop. The compressor has two stages, one with a variable geometry diffuser and one with a fixed geometry diffuser.

Abstract: A centrifugal compressor for a refrigeration system is disclosed. The centrifugal compressor includes an electric motor, which includes a rotor and a stator. The compressor further includes a housing enclosing the electric motor, a stator cooling passage provided within the housing, and a rotor cooling passageway provided within the housing. The rotor cooling passageway is independent of the stator cooling passageway.

Abstract: One exemplary embodiment of this disclosure relates to a centrifugal refrigerant compressor system. The system includes a condenser, an evaporator, and an economizer between the condenser and the evaporator. The system further includes a centrifugal compressor having a first impeller and a second impeller downstream of the first impeller. The compressor includes at least one port. Fluid from a recirculation flow path and an economizer flow path is introduced into a main flow path of the compressor by way of the at least one port.

Abstract: A centrifugal compressor for a refrigeration system is disclosed. The centrifugal compressor includes an electric motor, which includes a rotor and a stator. The compressor further includes a housing enclosing the electric motor, a stator cooling passage provided within the housing, and a rotor cooling passageway provided within the housing. The rotor cooling passageway is independent of the stator cooling passageway.

Abstract: A refrigerant compressor includes a housing providing a refrigerant outlet having a throat. An electric motor is provided in the housing to directly drive an impeller via a shaft about an axis in response to a variable speed command. The impeller includes an outlet end aligned with variable geometry diffuser. A magnetic bearing assembly rotationally supports the shaft relative to the housing in response to a magnetic bearing command. A member is arranged to adjust the throat area, and which can move in a direction generally parallel to the axis in response to an actuator receiving a compressor regulation command. A controller is configured to respectively provide the variable speed command, the magnetic bearing command and the compressor regulation command to the electric motor to vary throat area, the magnetic bearing assembly and the actuator to obtain a desired compressor operation without the need of variable inlet geometry.

Abstract: This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

Abstract: This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

Abstract: One exemplary embodiment of this disclosure relates to a centrifugal refrigerant compressor system. The system includes a condenser, an evaporator, and an economizer between the condenser and the evaporator. The system further includes a centrifugal compressor having a first impeller and a second impeller downstream of the first impeller. The compressor includes at least one port. Fluid from a recirculation flow path and an economizer flow path is introduced into a main flow path of the compressor by way of the at least one port.

Abstract: A heat pump system includes a refrigerant circuit. First and second heat exchangers are arranged in the refrigerant circuit. A flow reversing device selectively changes a direction of flow in the refrigerant circuit between the first and second heat exchangers. A centrifugal compressor is arranged in the fluid circuit and has first and second impellers arranged in series relative to one another to provide a desired compressor pressure ratio. In one example, the centrifugal compressor mounts the first and second impellers on opposing ends of a shaft. The first and second impellers respectively include first and second stage inlets and outlets. One example desired compressor pressure ratio of at least 10:1 corresponds to a second stage outlet pressure to a first stage inlet pressure. A first diffuser is arranged at the first stage outlet, and the first diffuser is a variable geometry diffuser.

Abstract: A refrigeration system includes a chiller having a refrigerant loop. A compressor is part of and in fluid communication with the refrigerant loop. The compressor has two stages, one with a variable geometry diffuser and one with a fixed geometry diffuser.

Abstract: This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

Abstract: A compressor (22; 260; 300; 400) has a housing assembly (140) with a suction port (24), a discharge port (26), and an economizer port (58). An impeller (154) is mounted to be driven in at least a first condition so as to draw a main flow of fluid through the suction port and discharge the fluid from the discharge port. A diffuser (220; 302; 402) has a plurality of diffuser passages (222; 310, 308; 403). Each diffuser passage has an inlet (224) positioned to receive fluid from the impeller and an outlet (220) downstream of the inlet in the first condition. One or more passages (230, 231, 232, 234, 236, 268; 320, 330, 332; 412) are positioned to draw an economizer flow of fluid from the economizer port and deliver the economizer flow downstream of the impeller inlet (212) but upstream of the diffuser passage outlets (226).

Abstract: A refrigerant compressor includes a housing providing a refrigerant outlet having a throat. An electric motor is provided in the housing to directly drive an impeller via a shaft about an axis in response to a variable speed command. The impeller includes an outlet end aligned with variable geometry diffuser. A magnetic bearing assembly rotationally supports the shaft relative to the housing in response to a magnetic bearing command. A member is arranged to adjust the throat area, and which can move in a direction generally parallel to the axis in response to an actuator receiving a compressor regulation command. A controller is configured to respectively provide the variable speed command, the magnetic bearing command and the compressor regulation command to the electric motor to vary throat area, the magnetic bearing assembly and the actuator to obtain a desired compressor operation without the need of variable inlet geometry.

Abstract: A centrifugal compressor includes a housing providing in inlet, an impeller, a diffuser and a volute or collector. An electric motor is provided in the housing and is configured to drive at least one impeller via a shaft about an axis. The impeller includes an outlet end aligned with a diffuser and arranged at the throat. A variable fluid injector device is arranged downstream from the outlet end of the impeller in one example. The variable fluid injector device is configured to introduce high pressure fluid downstream from the impeller in response to a compressor regulation command. The injected fluid energizes the low momentum boundary layer, which provides compressor stability. A compressor controller is in communication with the variable fluid injection device to obtain a desired compressor operating condition.

Abstract: A compressor system having a centrifugal compressor, controller and an interface is disclosed. The compressor includes adjustable guide vanes and a variable geometry diffuser. The controller is in electrical communication with each of the guide vanes and diffuser so as to monitor and adjust positions thereof in accordance with a predetermined control algorithm. The control algorithm is implemented in accordance with a method of controlling the centrifugal compressor. The method adjusts the position of the diffuser based on the actual lift, guide vane position and predetermined relationships between diffuser position and reference lift.