A turbo chiller that has an oil-free configuration, which reduces the frequency of maintenance and maintenance-induced release of refrigerant, and can achieve a reduced environmental impact by utilizing the characteristics of the low-pressure refrigerant R1233zd(E) that reaches negative pressure at a saturation temperature of 18° C. or lower. The turbo chiller comprises a refrigeration cycle that includes a turbo compressor, a condenser, a decompression device, and an evaporator connected in sequence via piping and is filled with a refrigerant; wherein the refrigerant is a low-pressure refrigerant R1233zd(E) refrigerant with low global warming potential and low ozone depletion potential; the turbo compressor has a direct drive configuration in which a rotating shaft of impellers is directly joined to a motor; and the rotating shaft is supported by magnetic bearings.

A turbo chiller that has an oil-free configuration, which reduces the frequency of maintenance and maintenance-induced release of refrigerant, and can achieve a reduced environmental impact by utilizing the characteristics of the low-pressure refrigerant R1233zd(E) that reaches negative pressure at a saturation temperature of 18° C. or lower. The turbo chiller comprises a refrigeration cycle that includes a turbo compressor, a condenser, a decompression device, and an evaporator connected in sequence via piping and is filled with a refrigerant; wherein the refrigerant is a low-pressure refrigerant R1233zd(E) refrigerant with low global warming potential and low ozone depletion potential; the turbo compressor has a direct drive configuration in which a rotating shaft of impellers is directly joined to a motor; and the rotating shaft is supported by magnetic bearings.

A refrigeration system is disclosed. The refrigeration system includes a refrigeration circuit including a compressor, a condenser, an expansion valve, and an evaporator fluidly connected. A purge circuit is fluidly connected to the condenser. The purge circuit is configured to receive a purge stream from the condenser. The purge stream is a mixture including a refrigerant and non-condensables. The purge circuit includes a plurality of heat exchangers for condensing the purge stream such that the non-condensables and the refrigerant in the purge stream are separated.

A compressor 12 for use in a refrigerant circuit 11 using a refrigerating machine oil 60 being free of phosphoric ester and a refrigerant mixture inclusive of 1,1,2-trifluoroetylene includes a rolling piston 32 and a vane 33 in contact with the rolling piston 32 in a slidable manner. The rolling piston 32 and the vane 33 are formed of a base metal, the base metal being steel, and the base metal is exposed at a contact portion between the rolling piston 32 and the vane 33.

A compressor 12 for use in a refrigerant circuit 11 using a refrigerating machine oil 60 being free of phosphoric ester and a refrigerant mixture inclusive of 1,1,2-trifluoroetylene includes a rolling piston 32 and a vane 33 in contact with the rolling piston 32 in a slidable manner. The rolling piston 32 and the vane 33 are formed of a base metal, the base metal being steel, and the base metal is exposed at a contact portion between the rolling piston 32 and the vane 33.

A lubrication additive recovery system is provided for use with a vapor compression system. The vapor compression system includes a compressor having a bearing, a condenser and an evaporator. The lubrication additive recovery system includes a lubrication ring formed to define first and second through-holes, a first system by which a portion of a required supply of lubrication is drawn from the condenser and provided to the bearing through the first through-holes and a second system by which a remainder of the required supply of lubrication is recovered from the evaporator and provided along with compressor discharge gas to the bearing through the second through-holes.

A lubrication additive recovery system is provided for use with a vapor compression system. The vapor compression system includes a compressor having a bearing, a condenser and an evaporator. The lubrication additive recovery system includes a lubrication ring formed to define first and second through-holes, a first system by which a portion of a required supply of lubrication is drawn from the condenser and provided to the bearing through the first through-holes and a second system by which a remainder of the required supply of lubrication is recovered from the evaporator and provided along with compressor discharge gas to the bearing through the second through-holes.

A coolant system includes a multistage compressor having a plurality of surge detection sensors. A condenser is connected to an outlet of the multistage compressor. An economizer is connected to an outlet of the condenser and has a gaseous coolant outlet and a liquid coolant outlet. The liquid coolant outlet is connected to a cooler and the gaseous coolant outlet is connected to a second or later stage of the multistage compressor via a controllable valve. A controller is communicatively coupled to the surge detection sensors and the controllable valve. The controller includes a non-transitory medium storing instructions for causing the controller to detect an occurrence of a surge and restricting a flow through the controllable valve until the surge has ceased.

A coolant system includes a multistage compressor having a plurality of surge detection sensors. A condenser is connected to an outlet of the multistage compressor. An economizer is connected to an outlet of the condenser and has a gaseous coolant outlet and a liquid coolant outlet. The liquid coolant outlet is connected to a cooler and the gaseous coolant outlet is connected to a second or later stage of the multistage compressor via a controllable valve. A controller is communicatively coupled to the surge detection sensors and the controllable valve. The controller includes a non-transitory medium storing instructions for causing the controller to detect an occurrence of a surge and restricting a flow through the controllable valve until the surge has ceased.

The technologies described and recited herein pertain to a permanent magnet motor having multiple voltage taps so that the motor may run in multiple configurations, e.g., a low-range and a high-range, and have multiple optimal operating points.