US20250155171A1 - Refrigerant distributor, heat exchanger, and refrigeration cycle device - Google Patents

Refrigerant distributor, heat exchanger, and refrigeration cycle device Download PDF

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Publication number
US20250155171A1
US20250155171A1 US18/721,766 US202318721766A US2025155171A1 US 20250155171 A1 US20250155171 A1 US 20250155171A1 US 202318721766 A US202318721766 A US 202318721766A US 2025155171 A1 US2025155171 A1 US 2025155171A1
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United States
Prior art keywords
refrigerant
mixing portion
liquid
phase
inlet
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Pending
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US18/721,766
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English (en)
Inventor
Kosuke TATSUTA
Takashi Kobayashi
Hironori Hattori
Takanori Suwa
Takuya Kodama
Naoki Nakagawa
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Assigned to MITSUBISHI ELECTRIC CORPORATION reassignment MITSUBISHI ELECTRIC CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NAKAGAWA, NAOKI, TATSUTA, Kosuke, KODAMA, TAKUYA, HATTORI, HIRONORI, KOBAYASHI, TAKASHI, Suwa, Takanori
Publication of US20250155171A1 publication Critical patent/US20250155171A1/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F25B39/02—Evaporators
    • F25B39/028—Evaporators having distributing means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/40—Fluid line arrangements
    • F25B41/42—Arrangements for diverging or converging flows, e.g. branch lines or junctions

Definitions

  • the present disclosure relates to a refrigerant distributor, a heat exchanger, and a refrigeration cycle device.
  • An air conditioner comprises a refrigerant circuit that circulates a refrigerant.
  • the refrigerant circuit comprises a compressor that compresses the refrigerant, a throttle device that expands the refrigerant, an indoor heat exchanger that allows the refrigerant to exchange heat with indoor air, an outdoor heat exchanger that allows the refrigerant to exchange heat with outdoor air, and a refrigerant pipe connecting the compressor, the throttle device, the indoor heat exchanger, and the outdoor heat exchanger in a circular manner.
  • the indoor heat exchanger functions as an evaporator that absorbs heat from outside and evaporates the refrigerant.
  • the outdoor heat exchanger functions as an evaporator.
  • the refrigerant circulating in the refrigerant circuit is sent out from the throttle device in a gas-liquid two-phase state and flows into the evaporator, or more specifically, the indoor heat exchanger or the outdoor heat exchanger, and exchanges heat with air while flowing through heat transfer tubes incorporated in the evaporator.
  • a liquid-phase refrigerant contained in the refrigerant evaporates and turns into a gas-phase refrigerant.
  • the refrigerant thus changes from the gas-liquid two-phase state to a gas single-phase state while flowing through the heat transfer tubes. In other words, the refrigerant flows through some sections of the heat transfer tubes in the gas-liquid two-phase state and flows through the remaining sections of the heat transfer tubes in the gas single-phase state.
  • the indoor heat exchanger or the outdoor heat exchanger that functions as an evaporator thus comprises multiple heat transfer tubes and a refrigerant distributor that distributes the refrigerant to the heat transfer tubes, and distributes the refrigerant to each heat transfer tube. This reduces the flow rate of the refrigerant inside each heat transfer tube, thus reducing the pressure loss of the refrigerant.
  • the refrigerant pipe inside the evaporator includes a curved portion located upstream from the refrigerant distributor, a centrifugal force acts on the refrigerant in the gas-liquid two-phase state passing through the curved portion.
  • the refrigerant thus flows into the refrigerant distributor with the liquid-phase refrigerant contained in the refrigerant concentrated.
  • the amount of the liquid-phase refrigerant distributed to each heat transfer tube by the refrigerant distributor varies. The smaller an amount of the liquid-phase refrigerant distributed to a heat transfer tube is, the longer a section of the heat transfer tube through which the refrigerant flows in the gas single-phase state is.
  • the heat transfer coefficient of the refrigerant in the gas single-phase state is much lower than the heat transfer coefficient of the refrigerant in the gas-liquid two-phase state.
  • the heat exchange efficiency in the section of the heat transfer tube through which the refrigerant flows in the gas single-phase state is much lower than the heat exchange efficiency in the section through which the refrigerant flows in the gas-liquid two-phase state.
  • the heat transfer tube with a longer section through which the refrigerant flows in the gas single-phase state has a lower heat exchange efficiency.
  • the heat exchange efficiency of the evaporator decreases.
  • the refrigerant distributor described in Patent Literature 1 comprises an inlet tube into which a refrigerant in the gas-liquid two-phase state flows, a branch space in which the refrigerant in the gas-liquid two-phase state flowing from the inlet tube is mixed and split, multiple outlet tubes through which the refrigerant in the gas-liquid two-phase state split in the branch space flows out, an inflow path connecting the inlet tube to the branch space, and multiple outflow paths connecting the multiple outlet tubes to the branch space.
  • a mixing portion with a recess at a position facing the inflow path is located in the branch space.
  • the refrigerant distributor described in Patent Literature 1 reduces variations in the amount of the refrigerant sent out from each outlet tube to the corresponding heat transfer tube.
  • the refrigerant distributor described in Patent Literature 1 may fail to reduce variations in the amount of the refrigerant distributed to each heat transfer tube depending on the flow rate, the type, and the temperature of the refrigerant flowing into the refrigerant distributor.
  • an objective of the present disclosure is to reduce variations in the amount of the refrigerant distributed to each heat transfer tube, regardless of the flow rate, the type, and the temperature of the refrigerant when the refrigerant is distributed to multiple heat transfer tubes.
  • a refrigerant distributor comprises a mixing portion having a cylindrical shape.
  • the mixing portion has an inlet for inflow therethrough of a refrigerant at a first end of the mixing portion.
  • the mixing portion has a plurality of outlets for outflow therethrough of the refrigerant at a second end of the mixing portion opposite to the first end.
  • the mixing portion has a recess facing the inlet at the second end of the mixing portion.
  • the mixing portion guides the refrigerant flowing in from the inlet to flow along the first end of the mixing portion and a side wall of the mixing portion to diffuse the refrigerant in a circumferential direction of the second end, and then sends out the refrigerant from the plurality of outlets.
  • the above configuration reduces variations in the amount of the refrigerant sent out from each outlet, regardless of the flow rate, the type, and the temperature of the refrigerant in the gas-liquid two-phase state flowing into the mixing portion. This reduces variations in the amount of the refrigerant flowing into any heat transfer tube connected to each outlet, regardless of the flow rate, the type, and the temperature of the refrigerant.
  • the above configuration can reduce variations in the amount of the refrigerant distributed to each heat transfer tube, regardless of the flow rate, the type, and the temperature of the refrigerant when the refrigerant is distributed to the multiple heat transfer tubes.
  • FIG. 1 is a diagram of a refrigerant circuit in an air conditioner according to Embodiment 1 of the present disclosure
  • FIG. 2 is a Mollier diagram illustrating the state of a refrigerant circulating in the refrigerant circuit according to Embodiment 1 of the present disclosure
  • FIG. 3 is a schematic diagram of an indoor heat exchanger and an outdoor heat exchanger according to Embodiment 1 of the present disclosure
  • FIG. 4 A is a perspective view of a refrigerant distributor and an internal refrigerant pipe according to Embodiment 1 of the present disclosure
  • FIG. 4 B is a cross-sectional view of the internal refrigerant pipe according to Embodiment 1 of the present disclosure
  • FIG. 5 A is a perspective view of the refrigerant distributor according to Embodiment 1 of the present disclosure
  • FIG. 5 B is a plan view of the refrigerant distributor according to Embodiment 1 of the present disclosure
  • FIG. 6 is a cross-sectional view of the refrigerant distributor according to Embodiment 1 of the present disclosure taken along line VI-VI in FIG. 5 B ;
  • FIG. 7 is a graph illustrating the relationship between the height of a mixing portion and the liquid-phase refrigerant distribution ratio of a reference outlet tube according to Embodiment 1 of the present disclosure
  • FIG. 8 is a schematic diagram illustrating an example refrigerant flow inside the refrigerant distributor according to Embodiment 1 of the present disclosure
  • FIG. 9 A is a schematic diagram illustrating an example refrigerant flow inside the refrigerant distributor according to Embodiment 1 of the present disclosure when the liquid-phase refrigerant distribution ratio of the reference outlet tube is suppressed
  • FIG. 9 B is a schematic diagram illustrating an example refrigerant flow inside the refrigerant distributor according to Embodiment 1 of the present disclosure when the mixing portion has a height too small to suppress the liquid-phase refrigerant distribution ratio of the reference outlet tube
  • FIG. 9 C is a schematic diagram illustrating an example refrigerant flow inside the refrigerant distributor according to Embodiment 1 of the present disclosure when the mixing portion has a height too large to suppress the liquid-phase refrigerant distribution ratio of the reference outlet tube;
  • FIG. 10 is a graph illustrating the relationship between the mass flow rate of the refrigerant and the liquid-phase refrigerant distribution ratio of the reference outlet tube according to Embodiment 1 of the present disclosure
  • FIG. 11 is a graph illustrating the relationship between the height of the mixing portion and the liquid-phase refrigerant distribution ratio of the reference outlet tube according to Embodiment 1 of the present disclosure
  • FIG. 12 is a graph illustrating the relationship between the height of a mixing portion and a refrigerant pressure loss according to Embodiment 2 of the present disclosure
  • FIG. 13 is a graph illustrating a range of the height of a mixing portion according to a modification of Embodiment 2 of the present disclosure
  • FIG. 14 A is a plan view of a refrigerant distributor according to Embodiment 3 of the present disclosure
  • FIG. 14 B is a cross-sectional view of the refrigerant distributor according to Embodiment 3 of the present disclosure taken along line A-A in FIG. 14 A ;
  • FIG. 15 is a schematic diagram illustrating an example refrigerant flow inside the refrigerant distributor according to Embodiment of the present disclosure.
  • FIG. 16 is a longitudinal sectional view of a refrigerant distributor according to a modification of Embodiment 3 of the present disclosure.
  • a refrigerant distributor, a heat exchanger, and a refrigeration cycle device are described below with reference to the drawings.
  • the same reference signs denote the same components.
  • An air conditioner 100 illustrated in FIG. 1 conditions the air inside an air-conditioning target space such as an indoor space or an interior space of an automobile.
  • the air conditioner 100 is an example of a refrigeration cycle device.
  • the air conditioner 100 comprises a refrigerant circuit 10 that circulates a refrigerant and a control device 20 that controls the operation of the refrigerant circuit 10 .
  • the refrigerant circuit 10 comprises a compressor 1 that compresses the refrigerant, a throttle device 2 that expands the refrigerant and also switches a circulation direction of the refrigerant inside the refrigerant circuit 10 , an indoor heat exchanger 3 that is incorporated in an indoor unit 6 installed inside the air-conditioning target space and causes the refrigerant to exchange heat with the air inside the air-conditioning target space, an outdoor heat exchanger 4 that is incorporated in an outdoor unit 7 installed outside the air-conditioning target space and causes the refrigerant to exchange heat with the air outside the air-conditioning target space, and a main refrigerant pipe 5 that connects the compressor 1 , the throttle device 2 , the indoor heat exchanger 3 , and the outdoor heat exchanger 4 in a circular manner, wherein the refrigerant flows through the main refrigerant pipe 5 .
  • the indoor heat exchanger 3 and the outdoor heat exchanger 4 are examples of a heat exchanger.
  • the control device 20 comprises a processor that performs various processes and a memory that stores data and programs.
  • the processor in the control device 20 executes the programs stored in the memory and thereby functions as an operation controller that controls the operation of the refrigerant circuit 10 , controlling the operations of the compressor 1 , the throttle device 2 , the indoor unit 6 , and the outdoor unit 7 by transmitting control signals.
  • the throttle device 2 comprises an expansion valve for expanding the refrigerant and a four-way valve for switching the circulation direction of the refrigerant.
  • the control device 20 controls the four-way valve in the throttle device 2 to switch the circulation direction of the refrigerant, thus switching the operating state of the air conditioner 100 between a cooling operation state and a heating operation state.
  • the four-way valve causes the refrigerant to circulate in the direction indicated by arrow JJ in FIG. 1 .
  • the four-way valve causes the refrigerant to circulate in the direction indicated by arrow KK in FIG. 1 .
  • This causes the indoor heat exchanger 3 to function as a condenser and the outdoor heat exchanger 4 to function as an evaporator, thus heating the air inside the air-conditioning target space.
  • FIG. 2 is a Mollier diagram illustrating the state of a refrigerant circulating in the refrigerant circuit 10 .
  • the horizontal axis indicates the refrigerant enthalpy
  • the vertical axis indicates the refrigerant pressure.
  • FIG. 2 illustrates a saturated liquid line MM and a saturated vapor line NN. In an area in which an enthalpy H of the refrigerant is below the saturated liquid line MM, the refrigerant is in a liquid single-phase state.
  • the refrigerant In an area in which the enthalpy H of the refrigerant is above the saturated vapor line NN, the refrigerant is in a gas single-phase state, whereas in an area in which the enthalpy H of the refrigerant is above the saturated liquid line MM and below the saturated vapor line NN, the refrigerant is in a gas-liquid two-phase state.
  • the refrigerant as a low-pressure gas-phase refrigerant, is first compressed by the compressor 1 to turn into a high-pressure gas-phase refrigerant as illustrated with the path from point S to point T in FIG. 2 , and then flows into the outdoor heat exchanger 4 .
  • the refrigerant flowing into the outdoor heat exchanger 4 exchanges heat with the air outside the air-conditioning target space to dissipate heat, is condensed to turn into a high-pressure liquid-phase refrigerant as illustrated with the path from point T to point U in FIG. 2 , and then flows into the throttle device 2 .
  • the refrigerant is then expanded by the expansion valve in the throttle device 2 to be depressurized, turns into a low-pressure refrigerant in the gas-liquid two-phase state as illustrated with the path from point U to point V in FIG. 2 , and flows into the indoor heat exchanger 3 .
  • the refrigerant flowing into the indoor heat exchanger 3 exchanges heat with the air inside the air-conditioning target space to absorb heat, evaporates to turn into a low-pressure gas-phase refrigerant as illustrated with the path from point V to point S in FIG. 2 , and then flows into the compressor 1 .
  • the indoor unit 6 comprises a housing incorporating the indoor heat exchanger 3 , a fan that feeds air to the indoor heat exchanger 3 , and a motor that drives the fan according to a control by the control device 20 .
  • the fan is driven to rotate by the motor to cause air inside the air-conditioning target space to flow into the housing.
  • the indoor heat exchanger 3 causes the refrigerant to exchange heat with the air flowing into the housing.
  • the fan is driven to rotate by the motor to feed the air after heat exchange with the refrigerant into the air-conditioning target space.
  • the air-conditioning target space is thus air-conditioned.
  • the outdoor unit 7 comprises a housing incorporating the outdoor heat exchanger 4 , a fan that feeds air to the outdoor heat exchanger 4 , and a motor that drives the fan according to a control by the control device 20 .
  • the fan is driven to rotate by the motor to cause air outside the air-conditioning target space to flow into the housing.
  • the outdoor heat exchanger 4 causes the refrigerant to exchange heat with the air flowing into the housing.
  • the fan is driven to rotate by the motor to feed the air after heat exchange with the refrigerant out of the air-conditioning target space.
  • the indoor heat exchanger 3 has the same configuration as the outdoor heat exchanger 4 .
  • the indoor heat exchanger 3 and the outdoor heat exchanger 4 comprise eight heat transfer tubes 30 , a pair of refrigerant distributors 31 that are connected to both ends of each heat transfer tube 30 and distribute the refrigerant to each heat transfer tube 30 , and a pair of internal refrigerant pipes 32 connecting the refrigerant distributors 31 and the main refrigerant pipe 5 .
  • the refrigerant distributors 31 are located at the inlets of the indoor heat exchanger 3 and the outdoor heat exchanger 4 .
  • one of the pair of refrigerant distributors 31 is connected to the compressor 1 through the main refrigerant pipe 5 and one of the internal refrigerant pipes 32 , and the other is connected to the throttle device 2 through the main refrigerant pipe 5 and the other of the internal refrigerant pipes 32 .
  • the refrigerant sent out from the compressor 1 or the throttle device 2 flows into a refrigerant distributor 31 through the main refrigerant pipe 5 and the internal refrigerant pipe 32 , and is distributed to each heat transfer tube 30 by the refrigerant distributor 31 .
  • Each heat transfer tube 30 is connected to multiple radiator fins. The refrigerant distributed to each heat transfer tube 30 by the refrigerant distributor 31 exchanges heat with air through the radiator fins while flowing through each heat transfer tube 30 .
  • the refrigerant in the gas-liquid two-phase state sent out from the throttle device 2 flows into the refrigerant distributor 31 connected to the throttle device 2 , is distributed to each heat transfer tube 30 by the refrigerant distributor 31 , and exchanges heat with air while flowing through each heat transfer tube 30 .
  • the distribution of the refrigerant to the multiple heat transfer tubes 30 reduces the flow rate of the refrigerant flowing through each heat transfer tube 30 , thus reducing the refrigerant pressure loss and improving the heat exchange efficiency of the indoor heat exchanger 3 or the outdoor heat exchanger 4 as an evaporator.
  • the refrigerant in the gas-liquid two-phase state exchanges heat with air
  • a liquid-phase refrigerant contained in the refrigerant evaporates and turns into a gas-phase refrigerant.
  • the refrigerant thus changes from the gas-liquid two-phase state to the gas single-phase state with a much lower heat transfer coefficient while flowing through the heat transfer tubes.
  • the refrigerant flowing through each heat transfer tube 30 merges in the refrigerant distributor 31 connected to the compressor 1 and is sent out from the refrigerant distributor 31 to the compressor 1 .
  • the heat exchange efficiency of the evaporator can be improved by reducing variations in the length of the section in each heat transfer tube 30 in which the refrigerant flows in a gas single-phase state, or in other words, the section with low heat exchange efficiency.
  • the variations in the length of the section in which the refrigerant flows in the gas single-phase state can be reduced by reducing variations in a heat load of the refrigerant in each heat transfer tube 30 .
  • the heat load of the refrigerant in the heat transfer tube 30 is equal to the product of a mass flow rate of the refrigerant flowing through the heat transfer tube 30 and the difference in enthalpy between the refrigerant at the inlet and the refrigerant at the outlet of the heat transfer tube 30 .
  • Variations in the heat load of the refrigerant in each heat transfer tube 30 can thus be reduced by reducing variations in the mass flow rate of the refrigerant flowing through each heat transfer tube 30 .
  • the refrigerant distributor 31 reduces variations in the mass flow rate of the refrigerant flowing through each heat transfer tube 30 , thus reducing variations in the heat load of the refrigerant in each heat transfer tube 30 , reducing variations in the length of the section in each heat transfer tube 30 through which the refrigerant flows in the gas single-phase state, and improving the heat exchange efficiency of the evaporator.
  • FIG. 4 A is a perspective view of the internal refrigerant pipe 32 connected to the throttle device 2 through the main refrigerant pipe 5 and the refrigerant distributor 31 connected to the internal refrigerant pipe 32 .
  • the internal refrigerant pipe 32 comprises a joint portion 39 that has a linear shape and is connected to the main refrigerant pipe 5 , a curved portion 40 that is U-shaped and is located downstream from the joint portion 39 , and a straight tube portion 41 that has a linear shape and is located downstream from the curved portion 40 .
  • the straight tube portion 41 has a downstream end connected to the refrigerant distributor 31 .
  • FIG. 4 B is a cross-sectional view of the internal refrigerant pipe 32 cut along a cut surface perpendicular to a direction in which the joint portion 39 and the straight tube portion 41 extend.
  • an XYZ orthogonal coordinate system is defined as illustrated in FIGS. 4 A and 4 B .
  • Z-axis is parallel to a gravity direction g.
  • X-axis is perpendicular to Z-axis and parallel to straight line TL passing through an axial center 39 a of the joint portion 39 and an axial center 41 a of the straight tube portion 41 .
  • Y-axis is perpendicular to X-axis and Z-axis.
  • the gas-phase refrigerant contained in the refrigerant flows through the center of the internal refrigerant pipe 32 , and the liquid-phase refrigerant contained in the refrigerant flows along the inner wall of the internal refrigerant pipe 32 in the form of a liquid film.
  • a difference in density between the gas-phase refrigerant and the liquid-phase refrigerant causes a difference in flow velocity between the gas-phase refrigerant and the liquid-phase refrigerant.
  • liquid-phase refrigerant in the form of a liquid film at the interface between the gas-phase refrigerant and the liquid-phase refrigerant, thus causing the liquid film to be scattered as droplets.
  • many liquid-phase refrigerants are at the center of the internal refrigerant pipe 32 as droplets together with the gas-phase refrigerant.
  • the straight tube portion 41 When the refrigerant flows through the straight tube portion 41 , a secondary flow occurs that uniformizes a thickness of the liquid film of the liquid-phase refrigerant adhering to the inner wall, thus reducing the concentration of the liquid-phase refrigerant.
  • the straight tube portion 41 is sufficiently long, the concentration of the liquid-phase refrigerant is eliminated while the refrigerant is flowing through the straight tube portion 41 , and the refrigerant flows into the refrigerant distributor 31 with no concentration of the liquid-phase refrigerant.
  • the straight tube portion 41 is shorter than the length that can eliminate the concentration of the liquid-phase refrigerant. The refrigerant thus flows into the refrigerant distributor 31 with the liquid-phase refrigerant concentrated in the positive X-direction.
  • the refrigerant distributor 31 comprises an inlet tube 50 connected to the internal refrigerant pipe 32 , a mixing portion 51 connected to the inlet tube 50 , multiple outlet tubes 52 connected to the mixing portion 51 , and a recess portion 53 connected to the mixing portion 51 .
  • An upstream end of the inlet tube 50 is connected to the straight tube portion 41 in the internal refrigerant pipe 32 , and a downstream end of the inlet tube 50 is connected to an inlet 510 formed at an upstream end 51 a of the mixing portion 51 .
  • the internal refrigerant pipe 32 is connected to the inlet 510 through the inlet tube 50 .
  • the upstream end 51 a of the mixing portion 51 is an example of a first end.
  • An inner diameter of the inlet tube 50 is equal to an inner diameter of the inlet 510 and is equal to an inner diameter of the straight tube portion 41 in the internal refrigerant pipe 32 .
  • the refrigerant in the gas-liquid two-phase state sent out from the throttle device 2 flows into the inlet tube 50 through the main refrigerant pipe 5 and the internal refrigerant pipe 32 .
  • the refrigerant flowing into the inlet tube 50 from the internal refrigerant pipe 32 flows into the mixing portion 51 from the inlet tube 50 through the inlet 510 .
  • the mixing portion 51 is hollow and has a cylindrical shape.
  • a downstream end 51 b of the mixing portion 51 is connected to the outlet tubes 52 and the recess portion 53 .
  • the downstream end 51 b of the mixing portion 51 is opposite to the upstream end 51 a and is an example of a second end.
  • the refrigerant distributor 31 comprises eight outlet tubes 52 that are as many as the heat transfer tubes 30 , and these outlet tubes 52 are connected to the eight heat transfer tubes 30 described above.
  • Each outlet tube 52 is connected to a different heat transfer tube 30 .
  • a downstream end of each outlet tube 52 is connected to the corresponding heat transfer tube 30 .
  • An upstream end of each outlet tube 52 is end connected to one of multiple outlets 511 at the downstream end 51 b of the mixing portion 51 .
  • each heat transfer tube 30 is connected to the corresponding outlet 511 through the corresponding outlet tube 52 .
  • the refrigerant flowing into the mixing portion 51 from the inlet tube 50 is sent out from the mixing portion 51 to each outlet tube 52 through the corresponding outlet 511 .
  • the refrigerant flowing into the mixing portion 51 is distributed to each outlet tube 52 .
  • the refrigerant flowing into each outlet tube 52 from the mixing portion 51 is sent out from the outlet tube 52 to the corresponding heat transfer tube 30 connected to the outlet tube 52 .
  • the refrigerant in the gas-liquid two-phase state flowing into the refrigerant distributor 31 is distributed to each heat transfer tube 30 .
  • An internal space of the recess portion 53 corresponds to a recess of the mixing portion 51 .
  • the recess portion 53 communicates with the mixing portion 51 through a circular opening 51 c formed at the downstream end 51 b of the mixing portion 51 and facing the inlet tube 50 and the inlet 510 .
  • the internal space of the recess portion 53 that is the recess of the mixing portion 51 , is formed at the downstream end 51 b of the mixing portion 51 and faces the inlet tube 50 and the inlet 510 .
  • the recess portion 53 has a shape of a cylinder with a hollow cone connected to the cylinder, the cylinder being connected to the opening 51 c in the mixing portion 51 . A part of the refrigerant sent out from the inlet 510 flows into the internal space of the recess portion 53 , and then flows into the mixing portion 51 from the recess portion 53 .
  • the refrigerant in the gas-liquid two-phase state flows into the refrigerant distributor 31 with the liquid-phase refrigerant contained in the refrigerant concentrating in the positive X-direction. If no countermeasures were taken, this would cause variations in the amount of the liquid-phase refrigerant sent out from each outlet 511 of the refrigerant distributor 31 to the corresponding outlet tube 52 .
  • the outlet tubes 52 are at positions different from each other in X-direction, and thus, if no countermeasures were taken, a larger amount of liquid-phase refrigerant would be sent out from an outlet tube 52 with a larger X-coordinate.
  • the outlet tube 52 with the largest X-coordinate, through which the largest amount of liquid-phase refrigerant would be sent out if no countermeasures were taken, is hereafter referred to as a reference outlet tube 52 a and distinguished from the other outlet tubes 52 .
  • the reference outlet tube 52 a and the other outlet tubes 52 are collectively and simply referred to as the outlet tubes 52 when there is no need to distinguish them from each other.
  • a height h (mm) of the mixing portion 51 satisfies Formula 1 below, where Di (mm) is the inner diameter of the inlet 510 illustrated in FIG. 6 , G (kg/h) is a mass flow rate of the refrigerant in the gas-liquid two-phase state flowing into the inlet tube 50 from the internal refrigerant pipe 32 , ⁇ g (kg/m 3 ) is a gas-phase density of the refrigerant, and ⁇ l (kg/m 3 ) is a liquid-phase density of the refrigerant.
  • FIG. 6 is a cross-sectional view of the refrigerant distributor 31 taken along line VI-VI in FIG. 5 B .
  • the height h of the mixing portion 51 is a distance between the upstream end 51 a and the downstream end 51 b of the mixing portion 51 in the internal space of the mixing portion 51 .
  • the gas-phase density ⁇ g of the refrigerant in the gas-liquid two-phase state is the density of the gas-phase refrigerant contained in the refrigerant
  • the liquid-phase density ⁇ l of the refrigerant is the density of the liquid-phase refrigerant contained in the refrigerant. More specifically, in the present embodiment, the height h of the mixing portion 51 is 2.5 to 4 mm inclusive.
  • this configuration can reduce variations in the amount of the refrigerant sent out from each outlet 511 through the corresponding outlet tube 52 , regardless of the flow rate, the type, and the temperature of the refrigerant in the gas-liquid two-phase state flowing through the inlet tube 50 .
  • a diameter Dc (mm) of the recess formed in the mixing portion 51 that is the internal space of the recess portion 53 is larger than the inner diameter Di of the inlet 510 .
  • the diameter Dc of the recess formed in the mixing portion 51 is equal to a diameter of the opening 51 c formed in the mixing portion 51 to which the recess portion 53 is connected. As described later, this configuration can reduce variations in the amount of the refrigerant sent out from each outlet 511 through the corresponding outlet tube 52 .
  • a first distance Li (mm) between the recess formed in the mixing portion 51 and an axial center QQ of each outlet 511 is larger than a second distance Lo (mm) between the axial center QQ of the outlet 511 and a side wall 51 d of the mixing portion 51 .
  • the axial center QQ of each outlet 511 aligns with the axial center of the corresponding outlet tube 52 connected to the outlet 511 .
  • the downstream end 51 b of the mixing portion 51 is circular, and the outlets 511 and the outlet tubes 52 are arranged apart from the recess portion 53 outwardly in the radial direction of the downstream end 51 b of the mixing portion 51 .
  • the eight outlet tubes 52 and the outlets 511 to which the respective outlet tubes 52 are connected are arranged on the circumference of a single circle centered on the axial center of the recess portion 53 .
  • the axial center of the mixing portion 51 aligns with the axial center of the recess.
  • This configuration facilitates processing in manufacturing the refrigerant distributor 31 , thus reducing the manufacturing cost.
  • the refrigerant distributor 31 is formed from a metal material such as copper or aluminum
  • the recess of the mixing portion 51 is formed by shaving the metal material with a drill.
  • the first distance Li is larger than the second distance Lo, and thus the distance between each outlet 511 and the recess of the mixing portion 51 is sufficiently large, facilitating processing and suppressing the manufacturing cost.
  • the material for the refrigerant distributor 31 is not limited to a metal material, and may be any material such as a resin.
  • the method for manufacturing the refrigerant distributor 31 is not limited to the method described above, and may be any method such as press forming or integral forming.
  • the distribution of the refrigerant performed by the refrigerant distributor 31 is described below using results of a simulation, performed using a computer, of the refrigerant flow inside the refrigerant distributor 31 .
  • the refrigerant in the gas-liquid two-phase state is assumed to flow into the inlet tube 50 with the liquid-phase refrigerant contained in the refrigerant concentrating in the positive X-direction.
  • This the simulation is performed under a condition in which the diameter Dc of the recess of the mixing portion 51 is 7 mm, the inner diameter Di of the inlet 510 is 6 mm, the first distance Li is 8.5 mm, and the second distance Lo is 2.5 mm.
  • R290 i.e. propane, is used as the refrigerant unless otherwise specified.
  • the temperature of the refrigerant in the simulation is 10° C.
  • FIG. 7 illustrates the relationship between the height h of the mixing portion 51 and the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a determined by simulation, when a mass flow rate G of the refrigerant flowing into the inlet tube 50 is 50 kg/h, 100 kg/h, 150 kg/h, or 200 kg/h.
  • the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a is a ratio of the mass flow rate of the liquid-phase refrigerant sent out from the outlet 511 connected to the reference outlet tube 52 a through the reference outlet tube 52 a to the sum of the mass flow rates of the liquid-phase refrigerant sent out from the respective outlets 511 through the corresponding outlet tubes 52 .
  • polygonal lines illustrating the relationship between the height h of the mixing portion 51 and the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a are curved downward, regardless of the value of the mass flow rate G of the refrigerant.
  • the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a reaches the minimum value when the height h of the mixing portion 51 is a specific value, and is greater than the minimum value when the height h is smaller than or larger than the specific value.
  • the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a can be reduced, reducing variations in the amount of the refrigerant sent out from each outlet 511 .
  • FIG. 8 illustrates an example refrigerant flow inside the refrigerant distributor 31 when the refrigerant in the gas-liquid two-phase state flows into the refrigerant distributor 31 with a liquid-phase refrigerant CC contained in the refrigerant concentrating in the positive X-direction.
  • FIG. 8 illustrates a vertical section of the refrigerant distributor 31 cut along a cut surface including the axial center of the inlet tube 50 and perpendicular to Y-direction.
  • arrow AA indicates a flow of the liquid-phase refrigerant CC contained in the refrigerant
  • arrow BB indicates a flow of the gas-phase refrigerant contained in the refrigerant.
  • the gas-phase refrigerant flows through the center of the inlet tube 50 , flows into the recess portion 53 after being sent out from the inlet 510 , hits the inner wall of the recess portion 53 , and diffuses in the circumferential direction of the opening 51 c in the mixing portion 51 .
  • the gas-phase refrigerant then flows along the inner wall of the recess portion 53 and flows into the mixing portion 51 .
  • the gas-phase refrigerant flowing into the mixing portion 51 hits, inside the mixing portion 51 , the liquid-phase refrigerant CC flowing along the inner wall of the inlet tube 50 in the form of a liquid film and flowing into the mixing portion 51 through the inlet 510 .
  • the gas-phase refrigerant flows along the downstream end 51 b of the mixing portion 51 toward the side wall 51 d of the mixing portion 51 .
  • FIGS. 9 A to 9 C illustrate vertical sections of the refrigerant distributor 31 cut along a cut surface including the axial center of the inlet tube 50 and perpendicular to Y-direction.
  • FIG. 9 A illustrates an example refrigerant flow inside the refrigerant distributor 31 when liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a is suppressed.
  • the gas-phase refrigerant hits the liquid-phase refrigerant CC inside the mixing portion 51 , thus causing the liquid-phase refrigerant CC to be pressed against the upstream end 51 a of the mixing portion 51 .
  • the pressed liquid-phase refrigerant CC flows along the upstream end 51 a , reaches the side wall 51 d of the mixing portion 51 , flows along the side wall 51 d , reaches the downstream end 51 b of the mixing portion 51 , and is sent out from the outlet 511 to the reference outlet tube 52 a .
  • the liquid-phase refrigerant CC diffuses in the circumferential direction of the downstream end 51 b of the mixing portion 51 while flowing along the upstream end 51 a and the side wall 51 d of the mixing portion 51 .
  • FIG. 9 B illustrates an example refrigerant flow inside the refrigerant distributor 31 when the height h of the mixing portion 51 is too small to suppress the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a .
  • the proportion occupied by the liquid-phase refrigerant CC in the internal space of the mixing portion 51 is higher than in the example in FIG. 9 A .
  • the flow rate of the gas-phase refrigerant flowing toward the side wall 51 d of the mixing portion 51 after colliding with the liquid-phase refrigerant CC inside the mixing portion 51 is lower than in the example in FIG.
  • the gas-phase refrigerant flowing toward the side wall 51 d of the mixing portion 51 flows along the downstream end 51 b of the mixing portion 51 , and then bends in a direction to flow into the reference outlet tube 52 a .
  • This causes apart of the liquid-phase refrigerant CC flowing in from the inlet 510 to be drawn by the gas-phase refrigerant bending in the direction to flow into the reference outlet tube 52 a and flow directly into the reference outlet tube 52 a without flowing along the upstream end 51 a and the side wall 51 d of the mixing portion 51 .
  • FIG. 9 C illustrates an example refrigerant flow inside the refrigerant distributor 31 when the height h of the mixing portion 51 is too great to suppress the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a .
  • the amount of the gas-phase refrigerant flowing toward the side wall 51 d of the mixing portion 51 without flowing into the recess portion 53 after flowing in from the inlet 510 is larger than in the example in FIG. 9 A .
  • the force of the gas-phase refrigerant acting on the liquid-phase refrigerant CC to press the liquid-phase refrigerant CC against the upstream end 51 a of the mixing portion 51 is lower than in the example in FIG. 9 A .
  • the liquid-phase refrigerant CC flows directly into the reference outlet tube 52 a without flowing along the upstream end 51 a and the side wall 51 d of the mixing portion 51 after flowing into the mixing portion 51 from the inlet 510 .
  • the liquid-phase refrigerant CC flowing in from the inlet 510 flows directly into the reference outlet tube 52 a , and thus, the liquid-phase refrigerant CC does not diffuse in the circumferential direction of the downstream end 51 b of the mixing portion 51 before being sent out from the outlet 511 to the reference outlet tube 52 a , the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a is not reduced, and variations in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 are not suppressed.
  • the liquid-phase refrigerant CC is restrained from directly flowing into the reference outlet tube 52 a , the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a is suppressed, variations in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 are suppressed.
  • the amount of the liquid-phase refrigerant CC sent out from each outlet 511 varies in the case where a centrifugal force acts on the refrigerant in the curved portion 40 in the internal refrigerant pipe 32 , as well as in the case where the gravity acts on the refrigerant in a direction that is not parallel to a direction of the refrigerant flow.
  • the gravity acts on the refrigerant flowing through the inlet tube 50 in a direction that is not parallel to the direction of the refrigerant flow, and the liquid-phase refrigerant CC contained in the refrigerant concentrates.
  • the refrigerant flows into the mixing portion 51 from the inlet 510 with the liquid-phase refrigerant CC concentrating due to the effect of the gravity and the liquid-phase refrigerant CC flows directly into the reference outlet tube 52 a , the amount of the liquid-phase refrigerant CC sent out from each outlet 511 varies.
  • the refrigerant distributor 31 were installed so that the axial center of the inlet tube 50 would be parallel to the gravity direction g when placing the refrigerant distributor 31 inside the indoor heat exchanger 3 or the outdoor heat exchanger 4 , the liquid-phase refrigerant CC would not concentrate due to the effect of the gravity described above.
  • installing the refrigerant distributor 31 so that the axial center of the inlet tube 50 would be exactly parallel to the gravity direction g is difficult, and the refrigerant distributor 31 is usually installed with the axial center of the inlet tube 50 slightly inclined with respect to the gravity direction g.
  • the diameter Dc of the recess of the mixing portion 51 is larger than the inner diameter Di of the inlet 510 .
  • FIG. 10 illustrates the relationship between the mass flow rate G of the refrigerant in the gas-liquid two-phase state flowing into the inlet tube 50 from the internal refrigerant pipe 32 and the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a determined by simulation, with the height h of the mixing portion 51 being 2, 3, 4, or 5 mm.
  • FIG. 11 illustrates the relationship between the height h of the mixing portion 51 and the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a determined by simulation when the refrigerants used are R290 and R134A, i.e. 1, 1, 1, 2-tetrafluoroethene.
  • a mass flow rate G of the refrigerant is 50 kg/h.
  • a density ratio ⁇ l / ⁇ g being the ratio of the liquid-phase density ⁇ l to the gas-phase density ⁇ g of R134A is higher than the density ratio ⁇ l / ⁇ g of R290.
  • the height h of the mixing portion 51 at which the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a reaches a minimum value is larger than when the refrigerant is R290 with a lower density ratio ⁇ l / ⁇ g , and the minimum value is smaller.
  • the mass flux of the refrigerant is proportional to the mass flow rate G of the refrigerant and inversely proportional to the square of the inner diameter Di of the inlet tube 50 .
  • the liquid-phase refrigerant distribution ratio of the reference outlet tube 52 a depends on the height h of the mixing portion 51 , the mass flow rate G of the refrigerant, the density ratio ⁇ l / ⁇ g of the refrigerant, and the mass flux of the refrigerant. Based on the above, Formula 2 below expressing a liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a is acquired by approximating the simulation results.
  • the simulation results indicate that, regardless of the height h of the mixing portion 51 , the mass flow rate G of the refrigerant, the type of the refrigerant, and the temperature of the refrigerant, a part of the liquid-phase refrigerant CC sent out from the inlet tube 50 flows directly into the reference outlet tube 52 a when the liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a is greater than 0.13, and the liquid-phase refrigerant CC does not flow directly into the reference outlet tube 52 a when the liquid-phase refrigerant distribution ratio X is less than 0.13.
  • the range of the height h of the mixing portion 51 within which the liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a represented by Formula 2 is less than 0.13 is expressed by Formula 1.
  • the height h of the mixing portion 51 satisfies Formula 1.
  • the height h of the mixing portion 51 is a value within a range expressed by Formula 1.
  • the liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a expressed by Formula 2 is less than 0.13, and the liquid-phase refrigerant CC contained in the refrigerant is restrained from flowing directly into the reference outlet tube 52 a , regardless of the mass flow rate G of the refrigerant, the type of the refrigerant, and the temperature of the refrigerant.
  • the mixing portion 51 since the height h of the mixing portion 51 satisfies Formula 1, the mixing portion 51 guides the refrigerant flowing in from the inlet 510 to flow along the upstream end 51 a and the side wall 51 d of the mixing portion 51 to diffuse the refrigerant in the circumferential direction of the downstream end 51 b of the mixing portion 51 , and then sends out the refrigerant from the outlet 511 , regardless of the mass flow rate G of the refrigerant, the type of the refrigerant, and the temperature of the refrigerant.
  • This configuration reduces variations in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 , regardless of the mass flow rate G of the refrigerant, the type of the refrigerant, and the temperature of the refrigerant. Moreover, restricting liquid-phase refrigerant CC from flowing directly into the reference outlet tube 52 a reduces variations in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 due to inclination of the axial center of the inlet tube 50 with respect to the gravity direction g.
  • the liquid-phase refrigerant CC is restrained from flowing directly into the reference outlet tube 52 a , regardless of the number of outlet tubes 52 , the inner diameter Di of the inlet 510 , the diameter Dc of the recess of the mixing portion 51 , the first distance Li, and the second distance Lo.
  • similar simulations were conducted with the height h of the mixing portion 51 set to various values within a range satisfying Formula 1, and the result showed that, when the height h of the mixing portion 51 is 2.5 to 4 mm inclusive, the liquid-phase refrigerant CC is significantly restrained from flowing directly into the reference outlet tube 52 a , regardless of the values of the above parameters.
  • the height h of the mixing portion 51 is 2.5 to 4 mm inclusive. This configuration reduces variations in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 , regardless of the mass flow rate G of the refrigerant, the type of the refrigerant, the temperature of the refrigerant, the number of outlet tubes 52 , the inner diameter Di of the inlet 510 , the diameter Dc of the recess of the mixing portion 51 , the first distance Li, and the second distance Lo.
  • the height h of the mixing portion 51 satisfies Formula 1.
  • the mixing portion 51 thus guides the refrigerant flowing in from the inlet 510 to flow along the upstream end 51 a of the mixing portion 51 and the side wall 51 d of the mixing portion 51 to diffuse the refrigerant in the circumferential direction of the downstream end 51 b , and then sends out the refrigerant from the outlet 511 .
  • This configuration reduces variations in the amount of the refrigerant sent out from each outlet 511 , regardless of the flow rate, the type, and the temperature of the refrigerant in the gas-liquid two-phase state flowing in from the inlet 510 .
  • this configuration can reduce variations in the amount of the refrigerant distributed to each heat transfer tube 30 when the refrigerant is distributed to the multiple heat transfer tubes 30 , regardless of the flow rate, the type, and the temperature of the refrigerant.
  • the refrigerant distributor 31 reduces variations in the amount of the refrigerant distributed to each heat transfer tube 30 , thus reducing variations in the heat load of the refrigerant in each heat transfer tube 30 and reducing variations in the section through which the refrigerant flows in the gas single-phase state in each heat transfer tube 30 .
  • This improves the heat exchange efficiency of the indoor heat exchanger 3 or the outdoor heat exchanger 4 that comprises the refrigerant distributor 31 and functions as an evaporator, and improves the air conditioning efficiency of the air conditioner 100 comprising the indoor heat exchanger 3 and the outdoor heat exchanger 4 .
  • the diameter Dc of the recess of the mixing portion 51 is larger than the inner diameter Di of the inlet 510 . This configuration can reduce variations in the amount of the refrigerant sent out from each outlet 511 .
  • the outlets 511 are located apart from the recess of the mixing portion 51 outwardly in the radial direction of the downstream end 51 b of the mixing portion 51 .
  • the first distance Li that is a distance between the recess of the mixing portion 51 and the axial center QQ of each outlet 511 is larger than the second distance Lo that is a distance between the axial center QQ of each outlet 511 and the side wall 51 d of the mixing portion 51 .
  • the diameter Dc of the recess of the mixing portion 51 is larger than the inner diameter Di of the inlet 510 , but this is a mere example.
  • the diameter Dc of the recess of the mixing portion 51 may be smaller than or equal to the inner diameter Di of the inlet 510 .
  • the first distance Li is larger than the second distance Lo, but this is a mere example.
  • the first distance Li may be smaller than or equal to the second distance Lo.
  • the height h of the mixing portion 51 is 2.5 to 4 mm inclusive, but this is a mere example.
  • the height h of the mixing portion 51 may be any value that satisfies Formula 1.
  • Embodiment 2 of the present disclosure which reduces a pressure loss of the refrigerant inside the refrigerant distributor 31 is described below, focusing on the differences from Embodiment 1.
  • the gas-phase density ⁇ g of the refrigerant is lower than or equal to 20 kg/m 3 , the deterioration of the energy-saving performance of the air conditioner 100 resulting from the pressure loss of the refrigerant inside the refrigerant distributor 31 is too large to be negligible.
  • the gas-phase density ⁇ g of the refrigerant is lower than or equal to 20 kg/m 3 .
  • the height h of the mixing portion 51 satisfies Formula 1, is larger than 10/3 mm, and is smaller than or equal to 4 mm. As described later, this configuration reduces the pressure loss of the refrigerant inside the refrigerant distributor 31 , and thus improves the energy-saving performance of the air conditioner 100 .
  • the reduction of the pressure loss of the refrigerant inside the refrigerant distributor 31 is described below using the results of a simulation, performed using a computer, of the refrigerant flow inside the refrigerant distributor 31 when the refrigerant in the gas single-phase state flows into the inlet tube 50 .
  • This simulation is performed under a condition in which the diameter Dc of the recess of the mixing portion 51 is 7 mm, the inner diameter Di of the inlet 510 is 6 mm, the first distance Li is 8.5 mm, and the second distance Lo is 2.5 mm.
  • R290 is used as the refrigerant.
  • the temperature of the refrigerant in the simulation is 10° C.
  • FIG. 12 illustrates the relationship between the height h of the mixing portion 51 and the pressure loss ⁇ P (kPa) of the refrigerant inside the refrigerant distributor 31 determined by simulation when the mass flow rate G of the refrigerant in the gas single-phase state flowing into the inlet tube 50 is 50, 100, 150, or 200 kg/h.
  • the pressure loss ⁇ P of the refrigerant inside the refrigerant distributor 31 is the difference between a pressure of the refrigerant when the refrigerant flows into the inlet tube 50 and a pressure of the refrigerant when the refrigerant is sent out from the outlet tube 52 .
  • the larger the height h of the mixing portion 51 is, the smaller the pressure loss ⁇ P of the refrigerant is, regardless of the mass flow rate G of the refrigerant.
  • the pressure loss ⁇ P of the refrigerant is proportional to the square of the velocity of the refrigerant.
  • the velocity pf the refrigerant is proportional to the mass flow rate G of the refrigerant and inversely proportional to the square root of the gas-phase density ⁇ g of the refrigerant.
  • the pressure loss ⁇ P of the refrigerant can thus be expressed by Formula 3 below.
  • f(h) is a function using the height h of the mixing portion 51 as a variable.
  • ⁇ ⁇ P f ⁇ ( h ) ⁇ G 2 ⁇ g ( 3 )
  • the pressure loss ⁇ P of the refrigerant when the height h of the mixing portion 51 is infinite is hereafter referred to as a reference pressure loss.
  • a ratio of the pressure loss ⁇ P of the refrigerant to the reference pressure loss is hereafter referred to as a pressure loss ratio.
  • the amount of increase in the value of the function f(h) when the height h of the mixing portion 51 increases by a unit amount gradually decreases.
  • the amount of decrease in the pressure loss ⁇ P of the refrigerant when the height h of the mixing portion 51 increases by a unit amount gradually decreases.
  • the pressure loss ratio When the pressure loss ratio is less than or equal to 130%, the amount of decrease in the pressure loss ⁇ P of the refrigerant when the height h of the mixing portion 51 increases by a unit amount is extremely small. Thus, when the pressure loss ratio is less than or equal to 130%, reducing the pressure loss ⁇ P of the refrigerant by increasing the height h of the mixing portion 51 is extremely difficult. The pressure loss ⁇ P of the refrigerant thus substantially reaches the minimum value when the pressure loss ratio is less than or equal to 130%.
  • the pressure loss ratio is less than or equal to 130% when the height h of the mixing portion 51 is larger than 10/3 mm.
  • the height h of the mixing portion 51 is larger than 10/3 mm. This configuration can suppress the pressure loss ⁇ P of the refrigerant to a substantially minimum value. This improves the energy-saving performance of the air conditioner 100 .
  • the pressure loss ratio is suppressed to less than or equal to 130%, regardless of the mass flow rate G of the refrigerant, the type of the refrigerant, the temperature of the refrigerant, the number of outlet tubes 52 , the inner diameter Di of the inlet tube 50 , the diameter Dc of the recess of the mixing portion 51 , the first distance Li, and the second distance Lo.
  • the height h of the mixing portion 51 is larger than 10/3 mm. This configuration reduces the pressure loss ⁇ P of the refrigerant inside the refrigerant distributor 31 and improves the energy-saving performance of the air conditioner 100 .
  • the height h of the mixing portion 51 is smaller than or equal to 4 mm, but this is a mere example, and the height h of the mixing portion 51 may be set to any value that satisfies Formula 1 and is larger than 10/3 mm.
  • the diameter Dc of the recess of the mixing portion 51 is 7 mm
  • the inner diameter Di of the inlet 510 is 6 mm
  • the first distance Li is 8.5 mm
  • the second distance Lo is 2.5 mm
  • the height h of the mixing portion 51 may be set to any value included in area FF illustrated in FIG. 13 .
  • R290 is used as the refrigerant
  • the temperature of the refrigerant is 10° C.
  • an area in which the height h of the mixing portion 51 is included below straight line DD is an area in which the height h of the mixing portion 51 is smaller than 10/3 mm
  • an area in which the height h of the mixing portion 51 is included above straight line DD is an area in which the height h of the mixing portion 51 is larger than 10/3 mm.
  • An area in which the mass flow rate G of the refrigerant is included below curve EE is an area in which the height h of the mixing portion 51 does not satisfy Formula 1
  • an area in which the mass flow rate G of the refrigerant is included above curve EE is in an area in which the height h of the mixing portion 51 satisfies Formula 1.
  • Area FF in which the height h of the mixing portion 51 is included above straight line DD and the mass flow rate G of the refrigerant is included above curve EE is an area in which the height h of the mixing portion 51 satisfies Formula 1 and is also larger than 10/3 mm.
  • Embodiment 3 of the present disclosure in which the refrigerant distributor 31 comprises a guide that guides the gas-phase refrigerant to the upstream end 51 a of the mixing portion 51 is described below, focusing on the differences from Embodiment 1.
  • the refrigerant distributor 31 differs from the refrigerant distributor 31 according to Embodiment 1 in that the refrigerant distributor 31 comprises a guide 54 connected to the downstream end 51 b of the mixing portion 51 .
  • the guide 54 is hatched in FIG. 14 A .
  • the guide 54 has an annular shape with the axial center aligned with the axial centers of the mixing portion 51 and the recess portion 53 as viewed from the front.
  • the guide 54 is located apart from the recess portion 53 outwardly in the radial direction of the downstream end 51 b of the mixing portion 51 .
  • the guide 54 is located apart from the recess of the mixing portion 51 that is the space inside the recess portion 53 outwardly in the radial direction of the downstream end 51 b of the mixing portion 51 . Moreover, the guide 54 is located apart from each outlet 511 and each outlet tube 52 inwardly in the radial direction of the downstream end 51 b of the mixing portion 51 .
  • FIG. 14 B is a cross-sectional view of the refrigerant distributor 31 according to the present embodiment taken along line A-A in FIG. 14 A .
  • the guide 54 comprises a first side wall 54 a inclined with respect to the downstream end 51 b of the mixing portion 51 and a second side wall 54 b perpendicular to the downstream end 51 b of the mixing portion 51 .
  • the first side wall 54 a is an example of a guide side wall.
  • the second side wall 54 b is located more outward than the first side wall 54 a in the radial direction of the downstream end 51 b of the mixing portion 51 .
  • the first side wall 54 a forms an angle ⁇ of 45° or greater and less than 90° with respect to the downstream end 51 b of the mixing portion 51 .
  • the first side wall 54 a has an inner end 60 and an outer end 61 located apart from the inner end 60 outwardly in the radial direction of the downstream end 51 b of the mixing portion 51 .
  • the inner end 60 of the first side wall 54 a connects to the downstream end 51 b of the mixing portion 51 .
  • the outer end 61 of the first side wall 54 a connects to the second side wall 54 b .
  • a third distance Lp that is a distance between the outer end 61 of the first side wall 54 a and the upstream end 51 a of the mixing portion 51 is smaller than a fourth distance Lq that is a distance between the inner end 60 of the first side wall 54 a and the upstream end 51 a of the mixing portion 51 .
  • the outer end 61 of the first side wall 54 a is located closer to the upstream end 51 a of the mixing portion 51 than the inner end 60 of the first side wall 54 a.
  • FIG. 15 illustrates an example refrigerant flow inside the refrigerant distributor 31 when the refrigerant in the gas-liquid two-phase state flows into the refrigerant distributor 31 with the liquid-phase refrigerant CC contained in the refrigerant concentrating in the positive X-direction.
  • FIG. 15 illustrates a vertical section of the refrigerant distributor 31 cut along a cut surface including the axial center of the inlet tube 50 and perpendicular to Y-direction.
  • arrow AA indicates the flow of the liquid-phase refrigerant CC
  • arrow BB indicates the flow of the gas-phase refrigerant.
  • the gas-phase refrigerant flowing into the recess portion 53 and then flowing into the mixing portion 51 from the recess portion 53 hits, inside the mixing portion 51 , the liquid-phase refrigerant CC flowing into the mixing portion 51 from the inlet 510 .
  • the liquid-phase refrigerant CC flows along the upstream end 51 a of the mixing portion 51 toward the side wall 51 d of the mixing portion 51 as indicated by arrow AA.
  • the gas-phase refrigerant flows along the downstream end 51 b of the mixing portion 51 toward the side wall 51 d of the mixing portion 51 and reaches the guide 54 as indicated by arrow BB.
  • the gas-phase refrigerant that has reached the guide 54 flows from the downstream end 51 b of the mixing portion 51 toward the upstream end 51 a along the first side wall 54 a of the guide 54 .
  • the gas-phase refrigerant is guided from the downstream end 51 b of the mixing portion 51 to the upstream end 51 a by the first side wall 54 a of the guide 54 .
  • the gas-phase refrigerant is restrained from flowing into the reference outlet tube 52 a
  • the liquid-phase refrigerant CC is restrained from being drawn by the gas-phase refrigerant flowing into the outlet 511 to flow directly into the reference outlet tube 52 a .
  • Restraining the liquid-phase refrigerant CC from flowing directly into the reference outlet tube 52 a suppresses the liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a , thus reducing variations in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 .
  • the gas-phase refrigerant is restrained from flowing into the reference outlet tube 52 a by the guide 54 even when the height h of the mixing portion 51 is smaller than a value necessary to suppress the liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a as in the example in FIG. 9 B described above.
  • This restrains the liquid-phase refrigerant CC from flowing directly into the reference outlet tube 52 a , reducing the liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a.
  • the first side wall 54 a of the guide 54 has an angle ⁇ of 45° or greater and less than 90° with respect to the downstream end 51 b of the mixing portion 51 .
  • the refrigerant distributor 31 guides, with the guide 54 connected to the downstream end 51 b of the mixing portion 51 , the gas-phase refrigerant flowing into the mixing portion 51 from the downstream end 51 b of the mixing portion 51 to the upstream end 51 a .
  • the liquid-phase refrigerant CC can be restrained from flowing directly into the reference outlet tube 52 a , the liquid-phase refrigerant distribution ratio X of the reference outlet tube 52 a can be suppressed, and variations in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 can be reduced.
  • FIG. 16 is a vertical section of the refrigerant distributor 31 according to a modification cut along a cut surface including the axial center of the inlet tube 50 and perpendicular to Y-direction.
  • the second side wall 54 b of the guide 54 is located more inward than the first side wall 54 a in the radial direction of the downstream end 51 b of the mixing portion 51 .
  • the first side wall 54 a of the guide 54 forms an angle ⁇ of 45° or greater and less than 90° with respect to the downstream end 51 b of the mixing portion 51 as in Embodiment 3 described above.
  • the inner end 60 of the first side wall 54 a connects to the second side wall 54 b .
  • the outer end 61 of the first side wall 54 a connects to the downstream end 51 b of the mixing portion 51 .
  • the third distance Lp that is a distance between the outer end 61 of the first side wall 54 a and the upstream end 51 a of the mixing portion 51 is smaller than the fourth distance Lq that is a distance between the inner end 60 of the first side wall 54 a and the upstream end 51 a of the mixing portion 51 .
  • the outer end 61 of the first side wall 54 a is located closer to the upstream end 51 a of the mixing portion 51 than the inner end 60 of the first side wall 54 a.
  • the second side wall 54 b of the guide 54 is perpendicular to the downstream end 51 b of the mixing portion 51 , but this is a mere example.
  • the second side wall 54 b of the guide 54 may have an angle less than 90° with respect to the downstream end 51 b of the mixing portion 51 .
  • the air conditioner 100 is used as a specific example of the refrigeration cycle device, but this is a mere example.
  • the refrigeration cycle device according to one or more embodiments of the present disclosure may be a refrigeration cycle device other than an air conditioner, such as a heat pump water heater, a refrigerator, or a freezer.
  • the indoor heat exchanger 3 and the outdoor heat exchanger 4 that are examples of a heat exchanger cause the refrigerant to exchange heat with air, but this is a mere example.
  • the heat exchanger in one or more embodiments of the present disclosure may cause the refrigerant to exchange heat with any substance.
  • the heat exchanger when the heat exchanger in one or more embodiments of the present disclosure is included in a heat pump water heater, the heat exchanger causes the refrigerant to exchange heat with water.
  • the refrigerant distributors 31 are located at the inlets of the indoor heat exchanger 3 and the outdoor heat exchanger 4 , but this is a mere example.
  • the refrigerant distributor according to one or more embodiments of the present disclosure may be located in the middle of a heat exchanger.
  • a reheat dehumidification air conditioner is known in which a throttle device is located in the middle of refrigerant paths of an indoor heat exchanger, and during the cooling operation, multiple refrigerant paths located upstream from the throttle device function as a condenser, and multiple refrigerant paths located downstream from the throttle device function as an evaporator.
  • the refrigerant distributor may be located in the middle of the refrigerant paths of the indoor heat exchanger and distribute the refrigerant to the multiple refrigerant paths downstream from the throttle device.
  • the number of heat transfer tubes 30 and outlet tubes 52 are set to be eight, but this is a mere example.
  • the number of heat transfer tubes 30 and outlet tubes 52 may be any number greater than two.
  • the recess portion 53 has a shape of a cylinder with a cone connected to the cylinder, but this is a mere example.
  • the recess portion 53 may have any shape.
  • the recess portion 53 may have a hemispherical shape.
  • the inner diameter of the inlet tube 50 is equal to the inner diameter of the straight tube portion 41 in the internal refrigerant pipe 32 , but this is a mere example.
  • the inner diameter of the inlet tube 50 may be different from the inner diameter of the straight tube portion 41 .
  • the inlet tube 50 and the straight tube portion 41 may be connected in any manner.
  • the inlet tube 50 and the straight tube portion 41 may be connected with a pipe having a tapered shape in which the inner diameter gradually decreases.
  • the inlet tube 50 and the straight tube portion 41 may be connected with a stepped rod-like pipe.
  • the internal refrigerant pipe 32 is connected to the inlet 510 through the inlet tube 50 , but this is a mere example.
  • the internal refrigerant pipe 32 may be directly connected to the inlet 510 .
  • an end of the internal refrigerant pipe 32 functions as the inlet tube 50 .
  • each heat transfer tube 30 is connected to the corresponding outlet 511 through the corresponding outlet tube 52 , but this is a mere example.
  • Each heat transfer tube 30 may be directly connected to the corresponding outlet 511 .
  • an end of each heat transfer tube 30 functions as the outlet tube 52 .
  • Embodiments 1 to 3 described above may be combined with one another.
  • the refrigerant distributor 31 according to Embodiment 2 may be provided with the guide 54 according to Embodiment 3. This configuration reduces variations in the amount of the refrigerant sent out from each outlet tube 52 and also reduces the pressure loss of the refrigerant inside the refrigerant distributor 31 , thus improving the energy-saving performance of the air conditioner 100 .

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US18/721,766 2022-02-09 2023-02-02 Refrigerant distributor, heat exchanger, and refrigeration cycle device Pending US20250155171A1 (en)

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JP2022019015 2022-02-09
JP2022-019015 2022-02-09
PCT/JP2023/003414 WO2023153309A1 (ja) 2022-02-09 2023-02-02 冷媒分配器、熱交換器及び冷凍サイクル装置

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4512368A (en) * 1982-03-20 1985-04-23 Sumitomo Metal Industries, Ltd. Fluid distributor
US20150000332A1 (en) * 2012-02-10 2015-01-01 Daikin Industries, Ltd. Air conditioner
US20170276414A1 (en) * 2015-01-16 2017-09-28 Mitsubishi Electric Corporation Distributor and refrigeration cycle apparatus
US20170328653A1 (en) * 2016-05-11 2017-11-16 Hamilton Sundstrand Corporation Flow distributor for two-phase flow
US20190056158A1 (en) * 2015-10-26 2019-02-21 Mitsubishi Electric Corporation Refrigerant distributor and air-conditioning apparatus using the same
WO2019167909A1 (ja) * 2018-03-02 2019-09-06 パナソニックＩｐマネジメント株式会社 熱交換器ユニットおよびそれを用いた空気調和機

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52112552U (https=) * 1976-02-24 1977-08-26
JPH0498055A (ja) * 1990-08-14 1992-03-30 Matsushita Refrig Co Ltd 冷媒分流器
JP2005114214A (ja) 2003-10-06 2005-04-28 Sharp Corp 冷媒分流器
JP2008298343A (ja) * 2007-05-30 2008-12-11 Daikin Ind Ltd 冷媒分流器一体化構造の膨張弁及びこれを用いた冷凍装置
JP2012141108A (ja) * 2011-01-05 2012-07-26 Toshiba Carrier Corp 分流器及び冷凍サイクル装置
JP2014081149A (ja) * 2012-10-17 2014-05-08 Hitachi Appliances Inc 冷媒分配器及びこれを備える冷凍サイクル装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4512368A (en) * 1982-03-20 1985-04-23 Sumitomo Metal Industries, Ltd. Fluid distributor
US20150000332A1 (en) * 2012-02-10 2015-01-01 Daikin Industries, Ltd. Air conditioner
US20170276414A1 (en) * 2015-01-16 2017-09-28 Mitsubishi Electric Corporation Distributor and refrigeration cycle apparatus
US20190056158A1 (en) * 2015-10-26 2019-02-21 Mitsubishi Electric Corporation Refrigerant distributor and air-conditioning apparatus using the same
US20170328653A1 (en) * 2016-05-11 2017-11-16 Hamilton Sundstrand Corporation Flow distributor for two-phase flow
WO2019167909A1 (ja) * 2018-03-02 2019-09-06 パナソニックＩｐマネジメント株式会社 熱交換器ユニットおよびそれを用いた空気調和機

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