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: Methods are directed towards dynamically determining refrigerant film thickness at the rolling-element bearing and for dynamically controlling refrigerant film thickness at the rolling-element bearing. Further, an oil free chiller system is configured for dynamically determining refrigerant film thickness at the rolling-element bearing of the oil free chiller system, wherein the oil free chiller system is also configured for dynamically controlling refrigerant film thickness at the rolling-element bearing of the oil free chiller system.

Abstract: Methods are directed towards dynamically determining refrigerant film thickness at the rolling-element bearing and for dynamically controlling refrigerant film thickness at the rolling-element bearing. Further, an oil free chiller system is configured for dynamically determining refrigerant film thickness at the rolling-element bearing of the oil free chiller system, wherein the oil free chiller system is also configured for dynamically controlling refrigerant film thickness at the rolling-element bearing of the oil free chiller system.

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 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 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: 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 compressor includes a bore, a rotor disposed within the bore, a compressor inlet, and a compressor outlet. The compressor further includes a compression chamber defined between the bore and the rotor, wherein a volume of the compression chamber gradually reduces from the compressor inlet to the compressor outlet. The compressor includes an economizer. The economizer is fluidically connected 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: 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: Methods are directed towards dynamically determining refrigerant film thickness at the rolling-element bearing and for dynamically controlling refrigerant film thickness at the rolling-element bearing. Further, an oil free chiller system is configured for dynamically determining refrigerant film thickness at the rolling-element bearing of the oil free chiller system, wherein the oil free chiller system is also configured for dynamically controlling refrigerant film thickness at the rolling-element bearing of the oil free chiller system.

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: 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 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 refrigerant system includes a compressor with a discharge valve that temporarily restricts the compressor's outflow at startup so that the discharge pressure can quickly rise to force lubricant back to the compressor. The discharge valve also helps prevent an axial face of a rotor of a screw compressor from rubbing against a bearing housing axial face of the compressor's housing. When the system turns off under certain low ambient air temperature conditions, the valve closes to help prevent the system's evaporator from freezing up. The discharge valve includes a novel arrangement of a piston, a valve stem extending from the piston, and a valve plug pivotally attached to the valve stem. The pivotal connection ensures a positive seal between the valve plug and a valve seat. A somewhat restricted fluid passageway between the valve's discharge chamber and piston chamber helps prevent the valve from chattering as the valve opens.

Abstract: A refrigerant system includes a compressor with a discharge valve that temporarily restricts the compressor's outflow at startup so that the discharge pressure can quickly rise to force lubricant back to the compressor. The discharge valve also helps prevent an axial face of a rotor of a screw compressor from rubbing against a bearing housing axial face of the compressor's housing. When the system turns off under certain low ambient air temperature conditions, the valve closes to help prevent the system's evaporator from freezing up. The discharge valve includes a novel arrangement of a piston, a valve stem extending from the piston, and a valve plug pivotally attached to the valve stem. The pivotal connection ensures a positive seal between the valve plug and a valve seat. A somewhat restricted fluid passageway between the valve's discharge chamber and piston chamber helps prevent the valve from chattering as the valve opens.