Abstract: Disclosed is a hermetic AC electric motor that includes harmonics shunting such that high frequency harmonics are shunted from the AC electric motor without the use of one or more high frequency filters in the associated motor drive. A related method of operating an AC electric motor includes shunting high frequency harmonics to a fluid passing through the AC electric motor. Also disclosed is a simplified variable speed motor drive system which eliminates the need for a filter for removing high frequency harmonics.

Abstract: Disclosed is a hermetic AC electric motor that includes harmonics shunting such that high frequency harmonics are shunted from the AC electric motor without the use of one or more high frequency filters in the associated motor drive. A related method of operating an AC electric motor includes shunting high frequency harmonics to a fluid passing through the AC electric motor. Also disclosed is a simplified variable speed motor drive system which eliminates the need for a filter for removing high frequency harmonics.

Abstract: A heat transfer circuit includes a compressor, a condenser, an expander, and an evaporator. The compressor includes a shaft that is rotated to compress a working fluid and a gas bearing to support the shaft. A conduit is configured to supply a portion of the working fluid to the compressor to cool the gas bearing. A method of controlling a heat transfer circuit includes directing a working fluid through a main flow path of the heat transfer circuit that directs the working fluid through a compressor, a condenser, an expander, an evaporator, and back to the compressor. The method also includes suppling supplying a portion of the working fluid in the main flow path to the compressor to cool a gas bearing of the compressor.

Abstract: A compressor includes a bore, a rotor disposed within the bore, a compressor inlet, a compressor outlet and a compression chamber defined between the bore and the rotor. A volume of the compression chamber gradually reduces from the compressor inlet to the compressor outlet. An economizer is configured to fluidically connect to the compression chamber. The economizer is configured to inject a working fluid into the compression chamber at an injection position. The injection position is changeable according to a working condition of the compressor.

Abstract: A screw compressor is disclosed. The screw compressor includes a suction inlet that receives a working fluid to be compressed; a compression mechanism fluidly connected to the suction inlet that compresses the working fluid; a discharge outlet fluidly connected to the compression mechanism that outputs the working fluid following compression by the compression mechanism; wherein the compression mechanism fluidly communicates with one or more outlets disposed at an intermediate location between the suction inlet and the discharge outlet, the one or more outlets being selectively fluidly connectable to the discharge outlet such that the working fluid can be provided from the one or more outlets to the discharge outlet.

Abstract: A compressor includes a housing, a shaft that is rotated relative to the housing to compress a working fluid, and a foil bearing that supports the shaft. The foil bearing includes a top foil. The foil bearing is a foil gas bearing that is backed up by a ball bearing, or a mesh foil bearing with an actuator to compress a wire mesh dampener. A heat transfer circuit includes a compressor and a working fluid. The compressor includes a shaft that is rotated to compress the working fluid, and a foil bearing for supporting the shaft as it rotates.

Abstract: A porous gas bearing is disclosed. The porous gas bearing includes a housing having a fluid inlet and an aperture. A porous surface layer is disposed within the housing surrounding the aperture in a circumferential direction. The porous surface layer is in fluid communication with the fluid inlet. A damping system includes a damping system including a biasing member, the biasing member being disposed in a passageway that extends along the longitudinal direction of the aperture and circumferentially about the aperture, wherein the biasing member is arranged radially outward from the porous surface layer.

Abstract: A scroll compressor includes a first scroll member, a second scroll member, and an aerostatic thrust bearing. The aerostatic thrust bearing forms a layer of gas between the second scroll member and a fixed supporting member to support the second scroll member as the second scroll member rotates and/or orbits. Also disclosed is a method of supporting a rotating/orbiting scroll member in a scroll compressor. The method including supplying pressurized gas to an aerostatic thrust bearing such that a layer of gas is formed between the rotating/orbiting scroll member and a fixed supporting member.

Abstract: A heat transfer circuit that includes a compressor with a gas bearing, a condenser, an expander, an evaporator, a lubricant stream, and a heat source. The lubricant stream receives a portion of the working fluid and supplies the portion of the working fluid to the gas bearing of the compressor. A method of supplying lubricant to a gas bearing of a compressor in a heat transfer circuit includes compressing and further heating at least a portion of the working fluid heated in the evaporator, and supplying the compressed and further heated working fluid to the gas bearing of the compressor. A method of the supplying lubricant to a gas bearing of a compressor in a heat circuit includes generating compressed gaseous working fluid within a lubricant stream.

Abstract: A compressor includes a bore, a rotor disposed within the bore, a compressor inlet, a compressor outlet and a compression chamber defined between the bore and the rotor. A volume of the compression chamber gradually reduces from the compressor inlet to the compressor outlet. An economizer is configured to fluidically connect to the compression chamber. The economizer is configured to inject a working fluid into the compression chamber at an injection position. The injection position is changeable according to a working condition of the compressor.

Abstract: A porous gas bearing is disclosed. The porous gas bearing includes a housing having a fluid inlet and an aperture. A porous surface layer is disposed within the housing surrounding the aperture in a circumferential direction. The porous surface layer is in fluid communication with the fluid inlet. A damping system includes a damping system including a biasing member, the biasing member being disposed in a passageway that extends along the longitudinal direction of the aperture and circumferentially about the aperture, wherein the biasing member is arranged radially outward from the porous surface layer.

Abstract: A porous gas bearing is disclosed. The porous gas bearing includes a housing having a fluid inlet and an aperture. A porous surface layer is disposed within the housing surrounding the aperture in a circumferential direction. The porous surface layer includes a plurality of segments arranged in a longitudinal direction of the aperture. The porous surface layer is in fluid communication with the fluid inlet. A damping system includes a plurality of dampers. The plurality of dampers is disposed circumferentially about the aperture. The plurality of dampers is arranged in between a first segment of the plurality of segments of the porous surface layer and a second segment of the plurality of segments of the porous surface layer.

Abstract: Control systems and methods for increasing efficiency of a compressor while the compressor capacity exceeds compressor load, by using a mechanical unloader such as a slide valve to reduce the internal volume ratio of the compressor and allow a more efficient speed to be maintained by a variable frequency drive (VFD) while reducing the compressor capacity based on the load. Control systems include the VFD, a controller for the VFD and the mechanical unloader, and temperature sensors. Compressor embodiments further include one or more compressors and mechanical unloaders operated by the control systems.

Abstract: A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

Abstract: A scroll compressor includes a first scroll member, a second scroll member, and an aerostatic thrust bearing. The aerostatic thrust bearing forms a layer of gas between the second scroll member and a fixed supporting member to support the second scroll member as the second scroll member rotates and/or orbits. Also disclosed is a method of supporting a rotating/orbiting scroll member in a scroll compressor. The method including supplying pressurized gas to an aerostatic thrust bearing such that a layer of gas is formed between the rotating/orbiting scroll member and a fixed supporting member.

Abstract: Systems and methods are used to control operation of a rotary compressor of a refrigeration system to improve efficiency by varying the volume ratio and the speed of the compressor in response to current operating and load conditions. The volume of the axial and/or radial discharge ports of the compressor can be varied to provide a volume ratio corresponding to operating conditions. In addition, permanent magnet motors and/or control of rotor tip speed can be employed for further efficiency gains.

Abstract: A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

Abstract: Systems and methods are used to control operation of a rotary compressor of a refrigeration system to improve efficiency by varying the volume ratio and the speed of the compressor in response to current operating and load conditions. The volume of the axial and/or radial discharge ports of the compressor can be varied to provide a volume ratio corresponding to operating conditions. In addition, permanent magnet motors and/or control of rotor tip speed can be employed for further efficiency gains.

Abstract: A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

Abstract: A porous gas bearing is disclosed. The porous gas bearing includes a housing having a fluid inlet and an aperture. A porous surface layer is disposed within the housing surrounding the aperture in a circumferential direction. The porous surface layer is in fluid communication with the fluid inlet. A damping system includes a damping system including a biasing member, the biasing member being disposed in a passageway that extends along the longitudinal direction of the aperture and circumferentially about the aperture, wherein the biasing member is arranged radially outward from the porous surface layer.