A pipe joint structure includes: a union; a flare nut that includes a female thread formed at one of axially opposite ends of the flare nut, and a first annular surface formed at the other of the axially opposite ends of the flare nut; a cylindrical sleeve that houses the flare nut such that the flare nut can be rotate and moved forward and backward; a rotary ring that has a second annular surface located to face the first annular surface, and is attached to the sleeve such that the rotary ring can be rotated for the union; and a pressing member that presses the flare nut toward the rotary ring. At the second annular surface, a claw is formed in such a manner as to protrude towards the flare nut. The first annular surface includes an engagement surface that is formed in such a manner to face one side in a circumferential direction and a helically inclined surface that is adjacent to the engagement surface in the circumferential direction and formed helically in such a way as to incline and face the opposite side of the one side in the circumferential direction.

The disclosure prevents a state where a liquid refrigerant is likely to be accumulated in an outdoor heat exchanger upon small load operation at low outdoor temperature during cooling operation. A junction part is disposed between a path and a liquid side inlet-outlet port, and includes a junction flow passage configured to cause a refrigerant flowing from the path to the liquid side inlet-outlet port to join and flow therein. A branching passage has a first end connected to the path, and a second end connected to the junction flow passage. An outdoor heat exchanger is configured to increase, upon decrease in load, a flow rate ratio of a refrigerant flowing to the branching passage to volume of a refrigerant flowing to the path.

The disclosure prevents a state where a liquid refrigerant is likely to be accumulated in an outdoor heat exchanger upon small load operation at low outdoor temperature during cooling operation. A junction part is disposed between a path and a liquid side inlet-outlet port, and includes a junction flow passage configured to cause a refrigerant flowing from the path to the liquid side inlet-outlet port to join and flow therein. A branching passage has a first end connected to the path, and a second end connected to the junction flow passage. An outdoor heat exchanger is configured to increase, upon decrease in load, a flow rate ratio of a refrigerant flowing to the branching passage to volume of a refrigerant flowing to the path.

A heating, ventilation, and/or air conditioning (HVAC) packaged unit includes a first refrigerant circuit component configured to change a temperature or a pressure of a refrigerant flowing through the first refrigerant circuit component and a second refrigerant circuit component configured to change a temperature or a pressure of the refrigerant flowing through the second refrigerant circuit component. The first and the second refrigerant circuit components are within a common refrigerant circuit that is disposed within a common support structure. The HVAC packaged unit also includes an interconnection conduit having a length formed from aluminum, a first end segment coupled to a first end of the length, and a second end segment coupled to a second end of the length. The first end segment and the second end segment are each formed from copper, and the interconnection conduit extends between the first refrigerant circuit component and the second refrigerant circuit component.

A relay includes a first relay unit and a second relay unit provided between an outdoor unit and an indoor unit to allow refrigerant to circulate between the first relay unit and the outdoor unit and between the second relay unit and the outdoor unit, and a heat medium circuit connecting the first relay unit and the second relay unit to the indoor unit to allow a heat medium to circulate through the heat medium circuit. The second relay unit is installed above or on a top of the first relay unit.

An outdoor heat exchanger includes a plurality of fins, a blower mechanism, a plurality of heat transfer pipes arranged side by side in a vertical direction, and a first flow divider connected to the plurality of heat transfer pipes. The plurality of heat transfer pipes includes a lowermost heat transfer pipe located on a lowermost side and at least one upper heat transfer pipe located above the lowermost heat transfer pipe. The upper heat transfer pipe includes a merging path connected to the first flow divider, a second flow divider provided at an end portion of the merging path, and at least two branch paths branched from the second flow divider, a flow resistance of a refrigerant in a liquid phase inside the upper heat transfer pipe is smaller than a flow resistance of the refrigerant in a liquid phase inside the lowermost heat transfer pipe.

An outdoor heat exchanger includes a plurality of fins, a blower mechanism, a plurality of heat transfer pipes arranged side by side in a vertical direction, and a first flow divider connected to the plurality of heat transfer pipes. The plurality of heat transfer pipes includes a lowermost heat transfer pipe located on a lowermost side and at least one upper heat transfer pipe located above the lowermost heat transfer pipe. The upper heat transfer pipe includes a merging path connected to the first flow divider, a second flow divider provided at an end portion of the merging path, and at least two branch paths branched from the second flow divider, a flow resistance of a refrigerant in a liquid phase inside the upper heat transfer pipe is smaller than a flow resistance of the refrigerant in a liquid phase inside the lowermost heat transfer pipe.

An air conditioner according to the present embodiment includes: an outdoor unit including a compressor, an outdoor heat exchanger, and a main expansion device, wherein a refrigerant is circulated by a refrigerant pipe configured to connect the compressor, the outdoor heat exchanger, and the main expansion device, an indoor unit including an indoor heat exchanger; and a connection pipe configured to connect the outdoor unit and the indoor unit, wherein the air conditioner has a cooling capability between 23 kW and 35 kW, a mixed refrigerant containing R32 of 50% or more is used as the refrigerant, and the refrigerant pipe comprises a ductile stainless steel pipe having a delta ferrite matrix structure of 1% or less on a basis of a grain area.

An air conditioner according to the present embodiment includes: an outdoor unit including a compressor, an outdoor heat exchanger, and a main expansion device, wherein a refrigerant is circulated by a refrigerant pipe configured to connect the compressor, the outdoor heat exchanger, and the main expansion device, an indoor unit including an indoor heat exchanger; and a connection pipe configured to connect the outdoor unit and the indoor unit, wherein the air conditioner has a cooling capability between 23 kW and 35 kW, a mixed refrigerant containing R32 of 50% or more is used as the refrigerant, and the refrigerant pipe comprises a ductile stainless steel pipe having a delta ferrite matrix structure of 1% or less on a basis of a grain area.

An apparatus for delivering circulating water includes a cooling/warming controller configured to perform heat exchange of circulating water supplied to a cooling/warming apparatus using a refrigerant; an indoor-unit controller configured to perform heat exchange of circulating water supplied to an indoor unit using the refrigerant; and a mode change unit (MCU) configured to control a flow of the refrigerant supplied to the cooling/warming controller and the indoor-unit controller according to an operation mode of the cooling/warming apparatus and the indoor unit. The cooling/warming controller and the indoor-unit controller may be configured to share a circulating water passage through which the circulating water moves.