Abstract: A method is described for operating a refrigerant circuit that includes a compressor with a driveshaft and one or more gas bearings for supporting the driveshaft. The method includes operating the refrigerant circuit in a first mode which includes supplying gaseous working fluid compressed by the compressor to the one or more gas bearings of the compressor, and the one or more gas bearings using the compressed gaseous working fluid to support the driveshaft. The method includes operating the refrigerant circuit in a second mode which includes supplying liquid working fluid to the one or more gas bearings of the compressor, and the one or more gas bearings using the liquid working fluid to support the driveshaft. A refrigerant circuit includes a compressor, a condenser, an expander, an evaporator, and a controller configured to selectively operate the refrigerant circuit in a least a first mode and a second mode.

Abstract: A compressor for a heat transfer circuit includes a variable frequency drive (VFD), an electric motor that rotates a driveshaft, bearing(s) for supporting the driveshaft, a backup gas supply, and a power supply. During a utility power interruption, the backup gas supply operates utilizing DC electrical power generated by a back electromotive force of the electric motor. A method of operating an electric power supply system for a compressor includes operating in a utility power mode and operating in a backup power mode during a utility power interruption. In the utility power mode, AC electrical power is supplied from the VFD to the motor. In the backup power mode, DC electrical power generated in the VFD by a back electromotive force of the motor it used to operate a backup gas supply to supply compressed working fluid to gas bearing(s) of the compressor.

Abstract: A gas bearing for a compressor includes a bearing portion and a sealing portion mounted to a bearing housing of the compressor via one or more dampers, and the sealing portion being fixedly connected to the bearing portion, and a vent with an inlet in the bearing. The bearing portion has an inner radial surface for radially supporting a shaft of the compressor. The sealing portion has a sealing surface. The inlet of the vent disposed between the inner radial surface and the sealing surface. The sealing surface and a rotating surface form a path that extends along the sealing surface. The path extending from a pressurized volume of the compressor to the vent, and the pressurized volume containing a fluid.

Abstract: A gas bearing for a compressor includes a bearing portion and a sealing portion mounted to a bearing housing of the compressor via one or more dampers, and the sealing portion being fixedly connected to the bearing portion, and a vent with an inlet in the bearing. The bearing portion has an inner radial surface for radially supporting a shaft of the compressor. The sealing portion has a sealing surface. The inlet of the vent disposed between the inner radial surface and the sealing surface. The sealing surface and a rotating surface form a path that extends along the sealing surface. The path extending from a pressurized volume of the compressor to the vent, and the pressurized volume containing a fluid.

Abstract: A compressor for a heat transfer circuit includes a variable frequency drive (VFD), an electric motor that rotates a driveshaft, bearing(s) for supporting the driveshaft, a backup gas supply, and a power supply. During a utility power interruption, the backup gas supply operates utilizing DC electrical power generated by a back electromotive force of the electric motor. A method of operating an electric power supply system for a compressor includes operating in a utility power mode and operating in a backup power mode during a utility power interruption. In the utility power mode, AC electrical power is supplied from the VFD to the motor. In the backup power mode, DC electrical power generated in the VFD by a back electromotive force of the motor it used to operate a backup gas supply to supply compressed working fluid to gas bearing(s) of the compressor.

Abstract: A variable orifice flow device controls the flow of refrigerant into a compressor motor housing in a compressor. The variable orifice flow device may include, for example, an electronic expansion valve, a thermal expansion valve, or a shuttling valve controlling the flow of refrigerant into a compressor motor housing. One or more flows of refrigerant may be through a fixed orifice, a valve seat of the variable orifice flow device, or leakage through a seal of the compressor motor housing, providing a baseline refrigerant flow to the inside of the compressor motor housing in addition to the flow through the variable orifice flow device.

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 heating, ventilation, air conditioning, and refrigeration (HVACR) system is disclosed. The HVACR system includes a refrigerant circuit. The refrigerant circuit includes a compressor, a condenser, an expansion device, and an evaporator fluidly connected. A controller is electronically connected to the compressor. The controller is configured to prevent the compressor from operating at a speed that is less than a minimum speed limit. A lubricant separator has an inlet fluidly connected between the compressor and the condenser and a plurality of outlets. A first of the plurality of outlets is fluidly connected to the condenser. A second of the plurality of outlets is fluidly connected to one or more components of the compressor to provide a lubricant to the one or more components.

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 heating, ventilation, air conditioning, and refrigeration (HVACR) system is disclosed. The HVACR system includes a refrigerant circuit. The refrigerant circuit includes a compressor, a condenser, an expansion device, and an evaporator fluidly connected. A controller is electronically connected to the compressor. The controller is configured to prevent the compressor from operating at a speed that is less than a minimum speed limit. A lubricant separator has an inlet fluidly connected between the compressor and the condenser and a plurality of outlets. A first of the plurality of outlets is fluidly connected to the condenser. A second of the plurality of outlets is fluidly connected to one or more components of the compressor to provide a lubricant to the one or more components.

Abstract: Methods, systems and apparatuses for mounting a motor rotor to a shaft of a compressor are disclosed. The shaft can include a rib region that is configured to form a press fit or a transition fit with the rotor bore. An end of the shaft can also include a plurality of crenulations that can be expanded outwardly in a radial direction relative to a centerline of the shaft. After the rotor is mounted onto the shaft, the crenulations can be expanded to eliminate the clearance between the shaft and the rotor to form a press fit with the rotor bore.

Abstract: A variable orifice flow device controls the flow of refrigerant into a compressor motor housing in a compressor. The variable orifice flow device may include, for example, an electronic expansion valve, a thermal expansion valve, or a shuttling valve controlling the flow of refrigerant into a compressor motor housing. One or more flows of refrigerant may be through a fixed orifice, a valve seat of the variable orifice flow device, or leakage through a seal of the compressor motor housing, providing a baseline refrigerant flow to the inside of the compressor motor housing in addition to the flow through the variable orifice flow device.

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: Methods, systems and apparatuses for mounting a motor rotor to a shaft of a compressor are disclosed. The shaft can include a rib region that is configured to form a press fit or a transition fit with the rotor bore. An end of the shaft can also include a plurality of crenulations that can be expanded outwardly in a radial direction relative to a centerline of the shaft. After the rotor is mounted onto the shaft, the crenulations can be expanded to eliminate the clearance between the shaft and the rotor to form a press fit with the rotor bore.

Abstract: Methods, systems and apparatuses for mounting a motor rotor to a shaft of a compressor are disclosed. The shaft can include a rib region that is configured to form a press fit or a transition fit with the rotor bore. An end of the shaft can also include a plurality of crenulations that can be expanded outwardly in a radial direction relative to a centerline of the shaft. After the rotor is mounted onto the shaft, the crenulations can be expanded to eliminate the clearance between the shaft and the rotor to form a press fit with the rotor bore.

Abstract: Methods, systems and apparatuses for mounting a motor rotor to a shaft of a compressor are disclosed. The shaft can include a rib region that is configured to form a press fit or a transition fit with the rotor bore. An end of the shaft can also include a plurality of crenulations that can be expanded outwardly in a radial direction relative to a centerline of the shaft. After the rotor is mounted onto the shaft, the crenulations can be expanded to eliminate the clearance between the shaft and the rotor to form a press fit with the rotor bore.

Abstract: A compressor for compressing refrigerant in a refrigerant circuit includes a housing defining a compression chamber. A screw rotor is mounted within the housing and configured to form a pocket of high pressure refrigerant and a pocket of low pressure refrigerant within the compression chamber. The screw rotor has a rotor shaft rotating about an axis. A bearing cavity includes at least one bearing rotatably supporting the rotor shaft. A partition through which the rotor shaft extends separates the bearing cavity from the compression chamber. A contacting seal is sealingly engaged with the rotor shaft and disposed in the bearing cavity proximate the partition. A passage has an opening adjacent the rotor shaft between the contacting seal and the compression chamber and in fluid communication with the pocket of low pressure refrigerant.

Abstract: A compressor for compressing refrigerant in a refrigerant circuit includes a housing defining a compression chamber. A screw rotor is mounted within the housing and configured to form a pocket of high pressure refrigerant and a pocket of low pressure refrigerant within the compression chamber. The screw rotor has a rotor shaft rotating about an axis. A bearing cavity includes at least one bearing rotatably supporting the rotor shaft. A partition through which the rotor shaft extends separates the bearing cavity from the compression chamber. A contacting seal is sealingly engaged with the rotor shaft and disposed in the bearing cavity proximate the partition. A passage has an opening adjacent the rotor shaft between the contacting seal and the compression chamber and in fluid communication with the pocket of low pressure refrigerant.