Abstract: A refrigeration system includes a compressor for compressing a refrigerant, a condenser for cooling the refrigerant, an evaporator for heating the refrigerant, and a lubrication system for providing a lubricant mist to a movable component of the compressor. The lubrication system includes an ejector arranged in fluid communication with the compressor and the evaporator, wherein the lubricant mist is carried by the refrigerant to the movable component.

Abstract: Disclosed is a direct-drive refrigerant screw compressor, having: a housing; a compression chamber in the housing; a pair of rotors, each rotor of the pair of rotors being rotationally disposed in the compression chamber and including an outer surface with a screw-geared profile; a fluid being disposed in the compression chamber, the fluid consisting of a working fluid for providing lubrication to each rotor; a first port extending through the housing and configured for directing the fluid toward the compression chamber; and when the compressor is activated, each rotor rotates and the fluid is distributed about each rotor to lubricate each rotor.

Abstract: Disclosed is a direct-drive refrigerant screw compressor, having: a housing; a compression chamber in the housing; a pair of rotors, each rotor of the pair of rotors being rotationally disposed in the compression chamber and including an outer surface with a screw-geared profile; a fluid being disposed in the compression chamber, the fluid consisting of a working fluid for providing lubrication to each rotor; a first port extending through the housing and configured for directing the fluid toward the compression chamber; and when the compressor is activated, each rotor rotates and the fluid is distributed about each rotor to lubricate each rotor.

Abstract: A pressure sensor includes a housing, an isolator positioned at a first end of the housing, and a first cavity formed between the first end of the housing and the isolator. The pressure sensor further includes a second cavity formed in the housing and a channel with a first end fluidly connected to the first cavity and a second end fluidly coupled to the second cavity. A pressure sensor chip is positioned in the second cavity and includes a first diaphragm positioned at a top side of the pressure sensor chip laterally outwards from the second end of the channel to prevent a fluid from jetting onto the first diaphragm.

Abstract: A pressure sensor includes a housing, an isolator positioned at a first end of the housing, and a first cavity formed between the first end of the housing and the isolator. The pressure sensor further includes a second cavity formed in the housing and a channel with a first end fluidly connected to the first cavity and a second end fluidly coupled to the second cavity. A pressure sensor chip is positioned in the second cavity and includes a first diaphragm positioned at a top side of the pressure sensor chip laterally outwards from the second end of the channel.

Abstract: A compressor system includes a compressor including a compressor inlet, a compressor outlet, and a bearing assembly, the compressor configured to compress a heat transfer fluid. An additive dispenser is fluidly coupled to the compressor upstream of the bearing assembly. The additive dispenser is configured to controllably release a volume of an additive material into the heat transfer fluid, the additive material configured to lubricate the bearing assembly. A method of lubricating a bearing assembly of compressor includes locating a volume of additive material at an additive dispenser fluidly coupled to a compressor, dispensing a portion of the additive material into the flow of heat transfer fluid at a selected time, flowing the heat transfer fluid containing the additive material to a bearing assembly of the compressor, and lubricating the bearing assembly of the compressor with the additive material.

Abstract: Disclosed is a direct-drive refrigerant screw compressor, having: a housing; a compression chamber in the housing; a pair of rotors, each rotor of the pair of rotors being rotationally disposed in the compression chamber and including an outer surface with a screw-geared profile; a fluid being disposed in the compression chamber, the fluid consisting of a working fluid for providing lubrication to each rotor; a first port extending through the housing and configured for directing the fluid toward the compression chamber; and when the compressor is activated, each rotor rotates and the fluid is distributed about each rotor to lubricate each rotor.

Abstract: A heat transfer system is disclosed that includes a plurality of electrocaloric elements including an electrocaloric film, a first electrode on a first side of the electrocaloric film, and a second electrode on a second side of the electrocaloric film. A fluid flow path is disposed along the plurality of electrocaloric elements, formed by corrugated fluid flow guide elements.

Abstract: A fluid damping structure includes first and second annular elements, first and second inner seals, a first outer seal, a damping chamber, a supply plenum, a fill port, and a plurality of fluid passages. The first and second inner seals are disposed radially between and are engaged with the first annular element and the second annular element. The first outer seal forms a sealing interface between the first and second annular elements. The first outer seal is disposed radially outward from the first and second inner seals. The damping chamber is defined by the first and second annular elements and the first and second inner seals. The supply plenum is disposed contiguous with an axial side of the damping chamber and extends from the second inner seal to the first outer seal. The fill port is in fluid communication with the supply plenum and a source of damping fluid.

Abstract: According to one aspect, a lubricant level sensing system for an actuator is provided. The lubricant level sensing system includes a pressure port in an outer housing of the actuator, a pressure sensor, and a pathway from the pressure port to the pressure sensor. The pathway establishes fluid communication between the pressure sensor and a free volume of an internal cavity of the outer housing relative to a lubricant level in the internal cavity such that the pressure sensor detects a pressure of the free volume used to derive the lubricant level.

Abstract: A refrigeration system includes a compressor for compressing a refrigerant, a condenser for cooling the refrigerant, an evaporator for heating the refrigerant, and a lubrication system for providing a lubricant mist to a movable component of the compressor. The lubrication system includes an ejector arranged in fluid communication with the compressor and the evaporator, wherein the lubricant mist is carried by the refrigerant to the movable component.

Abstract: A compressor system includes a compressor including a compressor inlet, a compressor outlet, and a bearing assembly, the compressor configured to compress a heat transfer fluid. An additive dispenser is fluidly coupled to the compressor upstream of the bearing assembly. The additive dispenser is configured to controllably release a volume of an additive material into the heat transfer fluid, the additive material configured to lubricate the bearing assembly. A method of lubricating a bearing assembly of compressor includes locating a volume of additive material at an additive dispenser fluidly coupled to a compressor, dispensing a portion of the additive material into the flow of heat transfer fluid at a selected time, flowing the heat transfer fluid containing the additive material to a bearing assembly of the compressor, and lubricating the bearing assembly of the compressor with the additive material.

Abstract: A ported shroud (60) for use in a compressor includes a body having a first end (42) and a second opposite end (46). The body is disposed concentrically about an axial passageway (50) and includes an inlet (40) for receiving a fluid flow formed adjacent the first end (42) and an outlet port (70) for discharging the fluid flow formed adjacent the second end (46). A toroidal volute (74) is disposed within the interior of the body and fluidly couples the inlet and the outlet.

Abstract: A fluid damping structure is provided that includes an inner and outer annular elements, first and second ring seals, first and second outer annular seals. The inner annular element has an outer radial surface and a plurality of annular grooves disposed in the outer radial surface. The outer annular element has an inner radial surface. A damping chamber is defined by the inner and outer annular elements, and the first and second inner ring seal. A first lateral chamber is disposed on a first axial side of the damping chamber. A second lateral chamber is disposed on a second axial side of the damping chamber. A plurality of fluid passages are disposed in at least one of the inner annular element or the inner ring seals. The fluid damping structure is configurable in an open configuration and a closed configuration.

Abstract: A vapor compression system (20) has: a centrifugal compressor (22) having an inlet (40) and an outlet (42); and an electric motor (28) having a stator (30) and a rotor (32). A plurality of bearings (36) support the rotor. A refrigerant charge comprises a base refrigerant and one or more oils. The one or more oils are present at a total concentration of 80-5000 parts per million (ppm) by weight.

Abstract: A bearing (20; 150; 152) comprises: an inner race (26); an outer race (28); and a plurality of rolling elements (30). The inner race comprises a nitrogen-alloyed steel (40). The outer race comprises a steel (42) with lower nitrogen content than said nitrogen-alloyed steel.

Abstract: According to one aspect, a lubricant level sensing system for an actuator is provided. The lubricant level sensing system includes a pressure port in an outer housing of the actuator, a pressure sensor, and a pathway from the pressure port to the pressure sensor. The pathway establishes fluid communication between the pressure sensor and a free volume of an internal cavity of the outer housing relative to a lubricant level in the internal cavity such that the pressure sensor detects a pressure of the free volume used to derive the lubricant level.

Abstract: A system (20; 300) comprises: a vapor compression loop (38; 338); a low-pressure or medium-pressure refrigerant in the loop; a centrifugal compressor (42) along the vapor compression loop and comprising: a housing (120); an inlet (44); an outlet (46); an impeller (140); an electric motor (122) coupled to the impeller to drive rotation of the impeller; and one or more refrigerant-lubricated bearings (130, 132).

Abstract: A heat transfer system is disclosed that includes a circulation loop of a heat transfer fluid that comprises a halocarbon. The circulation loop includes a compressor or pump that includes bearing rolling surfaces in contact with the heat transfer fluid. The bearing contact surface has a substrate a layer thereon that includes a polymer or oligomer having polar side groups and a tribofilm.

Abstract: According to one aspect, a lubricant level sensing system for an actuator is provided. The lubricant level sensing system includes a pressure port in an outer housing of the actuator, a pressure sensor, and a pathway from the pressure port to the pressure sensor. The pathway establishes fluid communication between the pressure sensor and a free volume of an internal cavity of the outer housing relative to a lubricant level in the internal cavity such that the pressure sensor detects a pressure of the free volume used to derive the lubricant level.