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.

A rotary cylinder piston compressor pump is provided, including a rotating shaft (2), a piston (3) and a cylinder (4). A rotating shaft hole (21) is provided in the rotating shaft (2). An oil guiding channel, provided in the cylinder (4), communicating with the rotating shaft hole (21). A recess (45) is formed in the inner end face of the cylinder (4). An oil path (61) sealed relative to a compression cavity (49) of the cylinder (4) is formed between the recess (45) and the piston (3). The oil path (61) between the recess (45) and the piston (3) is communicated with an oil path (62) between the piston (3) and the rotating shaft (2) and is communicated with the oil guiding channel by means of an oil returning channel. Also provided is a compressor including the compressor pump.

A rotary cylinder piston compressor pump is provided, including a rotating shaft (2), a piston (3) and a cylinder (4). A rotating shaft hole (21) is provided in the rotating shaft (2). An oil guiding channel, provided in the cylinder (4), communicating with the rotating shaft hole (21). A recess (45) is formed in the inner end face of the cylinder (4). An oil path (61) sealed relative to a compression cavity (49) of the cylinder (4) is formed between the recess (45) and the piston (3). The oil path (61) between the recess (45) and the piston (3) is communicated with an oil path (62) between the piston (3) and the rotating shaft (2) and is communicated with the oil guiding channel by means of an oil returning channel. Also provided is a compressor including the compressor pump.

A compressor includes: a stator core including a plurality of teeth around which an aluminum winding wire is wound in a concentrated manner; a rotor core disposed on an inner diameter side of the stator core and including a plurality of magnet insertion holes; and a plurality of ferrite magnets inserted in the magnet insertion holes, in which when a width of a winding wire portion formed in each of the teeth is represented as A, a length in an axis direction of the stator core is represented as L, and the number of slots is represented as S, the stator core has a shape that satisfies a relation of 0.3<S×A÷L<2.2.

A compressor includes: a stator core including a plurality of teeth around which an aluminum winding wire is wound in a concentrated manner; a rotor core disposed on an inner diameter side of the stator core and including a plurality of magnet insertion holes; and a plurality of ferrite magnets inserted in the magnet insertion holes, in which when a width of a winding wire portion formed in each of the teeth is represented as A, a length in an axis direction of the stator core is represented as L, and the number of slots is represented as S, the stator core has a shape that satisfies a relation of 0.3<S×A÷L<2.2.

A lubricant supply system is for a compressor that compresses a first working fluid in a heat transfer circuit. The lubricant supply system includes a lubricant tank, a lubricant pathway for supplying lubricant from the lubricant tank to one or more bearings of the compressor, and a lubricant refrigeration system with a lubricant heater and a lubricant cooler. The lubricant heater configured to heat the lubricant discharged from the one or more bearings and the lubricant cooler configured to cool the lubricant flowing through the lubricant pathway. A method of lubricating a compressor includes heating the lubricant, directing the lubricant from a lubricant tank through a lubricant pathway to one or more bearings of the compressor, and cooling the lubricant passing through the lubricant pathway.

A refrigeration cycle apparatus (1) is capable of performing a refrigeration cycle using a small-GWP refrigerant. The refrigeration cycle apparatus (1) includes a refrigerant circuit (10) and a refrigerant enclosed in the refrigerant circuit (10). The refrigerant circuit includes a compressor (21), a condenser (23), a decompressing section (24), and an evaporator (31). The refrigerant contains at least 1,2-difluoroethylene.

A refrigeration cycle apparatus (1) is capable of performing a refrigeration cycle using a small-GWP refrigerant. The refrigeration cycle apparatus (1) includes a refrigerant circuit (10) and a refrigerant enclosed in the refrigerant circuit (10). The refrigerant circuit includes a compressor (21), a condenser (23), a decompressing section (24), and an evaporator (31). The refrigerant contains at least 1,2-difluoroethylene.

An electric motor having a permanent magnet and a compressor including an electric motor are provided. The electric motor may include a stator; and a rotor rotatably disposed and spaced a predetermined gap apart from the stator. The rotor may include a rotational shaft, a permanent magnet arranged concentrically to the rotational shaft, and a permanent magnet support that supports the permanent magnet. The permanent magnet may have a cylindrical shape and be magnetized to have polar anisotropy such that a magnetic field is formed on the magnet's surface facing the gap but is not formed on the magnet's surface opposite to the gap. The permanent magnet support may be configured to form no flux path in the permanent magnet and connect the rotational shaft to the permanent magnet. Thus, the rotor has a reduced weight with consequent suppression of vibration and noise.

An electric motor having a permanent magnet and a compressor including an electric motor are provided. The electric motor may include a stator; and a rotor rotatably disposed and spaced a predetermined gap apart from the stator. The rotor may include a rotational shaft, a permanent magnet arranged concentrically to the rotational shaft, and a permanent magnet support that supports the permanent magnet. The permanent magnet may have a cylindrical shape and be magnetized to have polar anisotropy such that a magnetic field is formed on the magnet's surface facing the gap but is not formed on the magnet's surface opposite to the gap. The permanent magnet support may be configured to form no flux path in the permanent magnet and connect the rotational shaft to the permanent magnet. Thus, the rotor has a reduced weight with consequent suppression of vibration and noise.