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.

The present disclosure relates to a novel vapor compression refrigeration system, and the methods of making and using the vapor compression refrigeration system.

A cooling system includes: a compressor; a condenser; an expansion valve; an evaporator; an internal heat exchanger having a first conduit in heat exchanging contact with a second conduit, the first conduit being part of a high pressure fluid line between the condenser and the expansion valve, the second conduit being part of a low pressure fluid line between the evaporator and the compressor; a bypass line connecting the high pressure fluid line with the low pressure fluid line and for injecting small amounts of liquid fluid from the high pressure fluid line into the low pressure fluid line; a valve arranged in the bypass line for opening and closing the bypass line; and a control device for monitoring a load point of the compressor and controlling the valve to an open position when the load point exceeds a threshold.

A compressor includes a compression mechanism, a shaft, a motor, and a cooling medium delivery structure. The motor includes a rotor mounted on the shaft and a stator disposed radially outwardly of the rotor to form a gap between the rotor and the stator. The cooling medium delivery structure includes inlet and outlet conduits located to supply and discharge a cooling medium to and from the motor. The shaft has an external shape different than an internal shape of the rotor to form at least one axial passageway between the shaft and the rotor. The cooling medium is supplied through the gap and the at least one axial passageway to cool the rotor.

To reduce the possibility that temperature of refrigerant discharged from a compressor of a refrigeration apparatus becomes excessively high by controlling torque of a motor built into the compressor, the compressor includes the motor having rotation thereof controlled by inverter control. An inverter controller controls torque of the motor using inverter control when operation frequency of the compressor is at least one value within a range of from 10 Hz to 40 Hz. When at least the operation frequency is within the range of from 10 Hz to 40 Hz, torque of the motor is controlled, and under a predetermined condition in which temperature of refrigerant discharged from the compressor easily becomes excessively high, a device controller controls devices provided in a refrigerant circuit such that refrigerant sucked into the compressor is placed in a wet vapor state.

A fluid temperature control system according to an embodiment cools a fluid by means of a multiple refrigeration apparatus including a high-temperature-side refrigerator (100), a medium-temperature-side refrigerator (200) and a low-temperature-side refrigerator (300). The medium-temperature-side refrigerator (200) in the multiple refrigeration apparatus has a medium-temperature-side first evaporator (204) and a medium-temperature-side second evaporator (224). A high-temperature-side evaporator (104) of the high-temperature-side refrigerator (100) and a medium-temperature-side condenser (202) of the medium-temperature-side refrigerator (200) constitute a first cascade condenser (CC1). The medium-temperature-side second evaporator (224) of the medium-temperature-side refrigerator (200) and a low-temperature-side condenser (302) of the low-temperature-side refrigerator (300) constitute a second cascade condenser (CC2). The fluid allowed to flow by a fluid flow apparatus is cooled by the medium-temperature-side first evaporator (204) of the medium-temperature-side refrigerator (200), and is then cooled by the low-temperature-side evaporator (304) of the low-temperature-side refrigerator (300).

A method of cooling a motor coupled to a compressor of a chiller includes adjusting a position of a motor cooling valve located fluidly between the motor and a refrigerant source, using a motor temperature control system coupled to the motor cooling valve to regulate an amount of refrigerant introduced into the motor from the condenser according to a temperature control scheme performed as a function of a monitored temperature in the motor, a first temperature threshold, and a second temperature threshold lower than the first temperature threshold. The temperature control scheme includes a motor cooling control process that adjusts the position of the motor cooling valve based on a stator winding temperature set point relating to stator windings of the motor. A proportionally limited close command override associated with a first temperature range above the second temperature threshold proportionally limits a close command provided to the motor cooling valve.

A compressor of an air-conditioning device includes a scroll mechanism unit having a fixed scroll and an orbiting scroll that cooperates with the fixed scroll to compress refrigerant; an electric motion unit that provides revolution movement to the orbiting scroll; a first space portion provided between the scroll mechanism unit and the electric motion unit; an annular second space portion provided in a circumference of the scroll mechanism unit in a radial direction; a suction pipe connected to the first space portion, from which the refrigerant is sucked into the compressor; a communication path provided between the first space portion and the second space portion, to guide, to the second space portion, the refrigerant sucked from the suction pipe to the first space portion; and a discharge pipe that discharges, to outside of the compressor, the refrigerant that flows from the second space portion into the scroll mechanism unit and is compressed, and a part of the refrigerant between the first expansion valve and the second expansion valve is injected simultaneously to the first space portion and the second space portion.

The present disclosure provides a liquid-cooling type double-sided cooler, including a first cooling portion and a second cooling portion. In the liquid-cooling type double-sided cooler, another end of the first cooling portion is formed with a first communication hole that is configured to penetrate the first cooling liquid path and an outside of the first cooling portion, another end of the second cooling portion is formed with a second communication hole that is configured to penetrate the second cooling liquid path and an outside of the second cooling portion; and the first cooling portion and the second cooling portion are positioned such that the first communication hole and the second communication hole face each other, and the first cooling liquid path and the second cooling liquid path are connected with each other.

A system may include a compressor, a heat exchanger, an expansion device, and first and second working fluid flow paths. The compressor may include a compression mechanism and a motor. The heat exchanger may receive compressed working fluid from the compressor. The expansion device may be disposed downstream of the heat exchanger. The first working fluid flow path may fluidly connect the heat exchanger and the expansion device. The second working fluid flow path may be disposed downstream of the heat exchanger and may fluidly connect the heat exchanger with the compressor. The second working fluid flow path may provide compressed working fluid to the compression mechanism and to the motor.