An air conditioner including an outdoor unit having a compressor, an outdoor heat exchanger, a main expansion device, and a refrigerant pipe configured to connect the outdoor heat exchanger to the main expansion device; an indoor unit having an indoor heat exchanger; and a connection pipe configured to connect the outdoor unit to the indoor unit, wherein the air conditioner has refrigeration capacity of 2 kW to 7 kW, a R134a is used as the refrigerant, the refrigerant pipe is made of a ductile stainless steel material having a delta ferrite matrix structure of 1% or less on the basis of a grain area, and the refrigerant pipe includes a suction pipe that guides suction of a refrigerant into the compressor and has an outer diameter of 12.70 mm.

A refrigeration system, according to the present invention, has a standard refrigeration circuit, with a condenser connected to a low temperature evaporator and a medium temperature evaporator by a high-pressure liquid line, which are in turn connected to a compressor by a low-pressure vapour return line and a medium-pressure vapour return line, and the compressor is connected to the condenser by a high-pressure vapour line. A low-pressure booster is connected on the low-pressure vapour return line operating at a low compression ratio to boost the pressure of the low-pressure vapour return line to substantially the same pressure as the medium-pressure vapour return line.

The present invention relates to an air conditioner. The air conditioner according to the present embodiment has a refrigeration capacity of 7 kW to 11 kW, inclusive, and uses a refrigerant R32 as a refrigerant, and since a refrigerant pipe therein is made of a ductile stainless steel material having 1% or less of a delta-ferrite matrix structure with respect to the grain size area thereof, and includes a suction pipe guiding the suction of the refrigerant into a compressor and having an outer diameter of 15.88 mm, the refrigerant pipe can maintain strength and hardness as good as or better than those of a copper pipe, while also maintaining good processability.

The present invention relates to an air conditioner. The air conditioner according to the present embodiment has a refrigeration capacity of 7 kW to 11 kW, inclusive, and uses a refrigerant R32 as a refrigerant, and since a refrigerant pipe therein is made of a ductile stainless steel material having 1% or less of a delta-ferrite matrix structure with respect to the grain size area thereof, and includes a suction pipe guiding the suction of the refrigerant into a compressor and having an outer diameter of 15.88 mm, the refrigerant pipe can maintain strength and hardness as good as or better than those of a copper pipe, while also maintaining good processability.

A compression chamber includes the compression chamber partitioning member, an intermediate pressure chamber guides an intermediate pressure working fluid before injection to the compression chamber, and the intermediate pressure chamber and the compression chamber face each other with a compression chamber partitioning member interposed between the intermediate pressure chamber and the compression chamber. Further, the intermediate pressure chamber includes an intermediate pressure chamber inlet through which an intermediate pressure working fluid flows, an injection port inlet of an injection port through which the intermediate pressure working fluid is injected into the compression chamber, and a liquid reservoir formed at a position below the intermediate pressure chamber inlet, and the liquid reservoir is formed by the compression chamber partitioning member.

A compression chamber includes the compression chamber partitioning member, an intermediate pressure chamber guides an intermediate pressure working fluid before injection to the compression chamber, and the intermediate pressure chamber and the compression chamber face each other with a compression chamber partitioning member interposed between the intermediate pressure chamber and the compression chamber. Further, the intermediate pressure chamber includes an intermediate pressure chamber inlet through which an intermediate pressure working fluid flows, an injection port inlet of an injection port through which the intermediate pressure working fluid is injected into the compression chamber, and a liquid reservoir formed at a position below the intermediate pressure chamber inlet, and the liquid reservoir is formed by the compression chamber partitioning member.

A plurality of scroll compressors with different fixed volume indexes are connected in fluid parallel circuit and configured to selectively operate to maximize isentropic efficiency at different condensing temperatures. Different quantities of scroll compressors of different volume indexes may be selected based upon typical climate or geographic location environmental conditions to attempt to maximize efficiency. A controller may selectively operate different combinations of the compressors of different volume indexes bases up load demands and condensing temperature conditions, which may be determined in a variety of ways.

The propagation of a disproportionation reaction of a refrigerant is suppressed. Disclosed is a method that uses a composition as a refrigerant in a compressor, in which the composition includes one or more compounds selected from the group of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene, and 1,3,3,3-tetrafluoropropene, and the flow rate of the refrigerant flowing through a region around an ignition energy generation portion in the compressor under a predetermined high-pressure condition is greater than or equal to 1 m/s.

A pressure increase in a compressor is suppressed. Disclosed is a method that uses a composition as a refrigerant in a refrigerant circuit, in which the composition includes one or more compounds selected from the group consisting of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene, and 1,3,3,3-tetrafluoropropene, and in the refrigerant circuit, the total internal volume of a refrigerant pipe and a component that are connected to a compressor is greater than or equal to 0.7 times the internal volume of the compressor.

A stator includes a stator core having a yoke and a tooth, an insulator provided on the tooth, and a coil wound around the tooth via the insulator. The yoke has a first hole provided in an end surface in an axial direction of the stator core. The tooth has a second hole provided in the end surface. The second hole is provided at the center of the tooth in a circumferential direction of the stator core and arranged on a straight line passing through the first hole and extending in a radial direction of the stator core. The insulator has a first convex portion fitting into the first hole and a second convex portion fitting into the second hole.