Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
  • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
  • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
  • F28F9/02—Header boxes; End plates
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
  • F28F9/22—Arrangements for directing heat-exchange media into successive compartments, e.g. arrangements of guide plates
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
  • F28F9/26—Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators

Definitions

• This disclosure relates to a heat exchanger and a refrigeration cycle device that exchanges heat between a refrigerant and air.
• heat exchangers are known to have a configuration in which multiple heat transfer tubes are inserted into a header.
• the cross-sectional area of the flow path through which the refrigerant flows changes depending on the parts of the multiple heat transfer tubes that protrude into the header. This increases the pressure loss of the refrigerant flowing through the header, posing a problem of reduced refrigerant distribution performance.
• the heat exchanger disclosed in Patent Document 1 adjusts the spacing between the heat transfer tubes inserted into the header to suppress the generation of vortices in the header and reduce pressure loss.
• Patent Document 1 the insertion intervals of the heat transfer tubes into the header vary depending on the location. This makes the processing of openings in the header for inserting the heat transfer tubes complicated.
• the present disclosure has been made to solve the problems described above, and aims to provide a heat exchanger and refrigeration cycle device that can improve the refrigerant distribution performance while suppressing a decrease in the workability of the header.
• the heat exchanger disclosed herein comprises a plurality of heat transfer tubes through which a refrigerant flows, a lower header into which the lower ends of the heat transfer tubes are inserted and to which a refrigerant pipe through which the refrigerant flows, and an upper header into which the upper ends of the heat transfer tubes are inserted, and the average insertion length of the plurality of heat transfer tubes inserted into the lower header is shorter than the average insertion length of the plurality of heat transfer tubes inserted into the upper header.
• the insertion length of the lower header is shorter than the insertion length of the upper header, which improves the refrigerant distribution performance while suppressing deterioration in the workability of the header.
• FIG. 1 is a circuit diagram showing an air conditioning apparatus according to a first embodiment.
• 1 is a schematic configuration diagram showing a heat exchanger according to a first embodiment.
• FIG. FIG. 2 is a perspective view showing a row-connecting header according to the first embodiment;
• 1 is a cross-sectional view of a heat exchanger according to a first embodiment.
• FIG. 13 is a diagram for explaining an upper limit of the insertion length of a heat transfer tube in accordance with embodiment 2.
• FIG. 1 is a graph showing the relationship between ⁇ / ⁇ y and pressure loss.
• FIG. 11 is a cross-sectional view of a heat exchanger according to a third embodiment.
• FIG. 11 is a cross-sectional view of a heat exchanger according to a fourth embodiment.
• FIG. 1 is a circuit diagram showing the air-conditioning apparatus 100 according to embodiment 1.
• the air-conditioning apparatus 100 is an example of a refrigeration cycle apparatus. As shown in Fig. 1, the air-conditioning apparatus 100 has an outdoor unit 110, an indoor unit 120, and a refrigerant piping 130.
• the outdoor unit 110 has a compressor 111, a flow path switching valve 112, a heat exchanger 1, a blower 113, and an expansion valve 114.
• the indoor unit 120 has a heat exchanger 121 and a blower 122.
• the refrigerant piping 130 connects the flow path switching valve 112, the heat exchanger 1, the expansion valve 114, and the heat exchanger 121, and is a piping through which the refrigerant flows.
• the compressor 111 draws in a low-temperature, low-pressure refrigerant, compresses it, and discharges it as a high-temperature, high-pressure refrigerant.
• the flow path switching valve 112 switches the flow direction of the refrigerant in the refrigerant circuit, and is, for example, a four-way valve.
• the heat exchanger 1 exchanges heat between the refrigerant and the outdoor air.
• the heat exchanger 1 acts as a condenser during cooling operation, and as an evaporator during heating operation.
• the blower 113 is a device that sends outdoor air to the heat exchanger 121.
• the expansion valve 114 reduces the pressure of the refrigerant to expand it, and is, for example, an electronic expansion valve.
• the heat exchanger 121 exchanges heat between the indoor air and the refrigerant.
• the heat exchanger 121 acts as an evaporator during cooling operation and as a condenser during heating operation.
• the blower 122 is a device that sends indoor air to the heat exchanger 121, and is, for example, a cross-flow fan.
• FIG. 2 is a schematic diagram showing the heat exchanger 1 according to the first embodiment.
• the heat exchanger 1 functions as a condenser or an evaporator in a refrigeration cycle device such as an air conditioning device 100 or a refrigerator.
• the heat exchanger 1 has a heat transfer tube 2, a fin 3, a first lower header 4, a second lower header 5, and a row header 6.
• the vertical direction of the heat exchanger 1 is indicated by the Z axis
• the short side direction of the heat exchanger 1 among the directions perpendicular to the vertical direction is indicated by the X axis
• the longitudinal direction of the heat exchanger 1 is indicated by the Y axis.
• the heat transfer tubes 2 are, for example, flat tubes, and have multiple flow paths (not shown) formed inside through which the refrigerant flows.
• the heat transfer tubes 2 extend in the vertical direction.
• the heat transfer tubes 2 perform heat exchange between the refrigerant flowing through the internal flow paths and the air.
• the heat exchanger 1 has multiple heat transfer tubes 2.
• a first row 2A and a second row 2B are formed by the multiple heat transfer tubes 2 lined up in the longitudinal direction of the heat exchanger 1.
• the first row 2A and the second row 2B are lined up in the lateral direction of the heat exchanger 1.
• the fins 3 promote heat exchange between the refrigerant flowing inside the heat transfer tubes 2 and the air.
• the fins 3 are, for example, corrugated fins.
• the heat exchanger 1 has a plurality of fins 3.
• the plurality of fins 3 are provided between the two heat transfer tubes 2 forming the first row 2A and between the two heat transfer tubes 2 forming the second row 2B. Note that while only a portion of the heat transfer tubes 2 and fins 3 are shown in FIG. 2, in reality, the heat transfer tubes 2 and fins 3 are arranged alternately in the longitudinal direction with no gaps.
• the plurality of heat transfer tubes 2 are also arranged at equal intervals in the longitudinal direction.
• the first lower header 4 is a header arranged at the bottom of the heat exchanger 1.
• the lower ends of the heat transfer tubes 2 forming the first row 2A are inserted into the first lower header 4.
• the first refrigerant pipe 11, which is a part of the refrigerant pipe 130, is connected to the first lower header 4.
• the first lower header 4 functions as a gas header that distributes the gaseous refrigerant that flows in from the first refrigerant pipe 11 to the heat transfer tubes 2 forming the first row 2A.
• the first lower header 4 functions as a liquid header that causes the liquid refrigerant that has merged from the heat transfer tubes 2 forming the first row 2A to flow out to the first refrigerant pipe 11.
• the second lower header 5 is a header arranged at the lower part of the heat exchanger 1.
• the lower ends of the heat transfer tubes 2 forming the second row 2B are inserted into the second lower header 5.
• the second refrigerant pipe 12, which is a part of the refrigerant pipe 130, is connected to the second lower header 5.
• the second lower header 5 functions as a liquid header that causes the liquid refrigerant that has joined from the heat transfer tubes 2 forming the second row 2B to flow out to the second refrigerant pipe 12.
• the second lower header 5 functions as a gas header that distributes the gas refrigerant that has flowed in from the second refrigerant pipe 12 to the heat transfer tubes 2 forming the second row 2B.
• the first lower header 4 and the second lower header 5 correspond to the "lower header" in this disclosure.
• the row header 6 is a header provided on the upper part of the heat exchanger 1, facing the first lower header 4 and the second lower header 5.
• the upper ends of the heat transfer tubes 2 forming the first row 2A and the second row 2B are inserted into the row header 6.
• the row header 6 relays the flow of refrigerant between the heat transfer tubes 2 inserted into the first lower header 4 and the heat transfer tubes 2 inserted into the second lower header 5.
• the heat exchanger 1 functions as a condenser
• the row header 6 distributes the refrigerant that has joined from the heat transfer tubes 2 forming the first row 2A to the heat transfer tubes 2 forming the second row 2B.
• the row header 6 distributes the refrigerant that has joined from the heat transfer tubes 21 forming the second row 2B to the heat transfer tubes 2 forming the first row 2A.
• the row header 6 corresponds to the "upper header" in this disclosure.
• FIG. 3 is a perspective view showing the row-connecting header 6 according to the first embodiment.
• FIG. 3 shows a cross section of the heat exchanger 1 cut in the XZ plane.
• the row-connecting header 6 has a base 61 and a cover plate 62.
• the base 61 constitutes the bottom and sides of the row-connecting header 6, and has an open top.
• the bottom of the base 61 is formed with an opening (not shown) into which the heat transfer tube 2 is inserted.
• the multiple heat transfer tubes 2 are provided at equal intervals in the longitudinal direction.
• the multiple openings into which the multiple heat transfer tubes 2 are inserted are also formed at equal intervals.
• the upper ends of the heat transfer tubes 2 are located inside the row-connecting header 6.
• the cover plate 62 is a flat member that covers the opening formed on the top surface of the base 61.
• the cover plate 62 constitutes the upper part of the row-connecting header 6.
• the refrigerant flowing in from the first refrigerant pipe 11 flows into the first lower header 4.
• the refrigerant flowing in the first lower header 4 is distributed to the multiple heat transfer tubes 2 forming the first row 2A.
• the refrigerant that has flowed through the multiple heat transfer tubes 2 forming the first row 2A joins at the row-to-row header 6 and is distributed to the multiple heat transfer tubes 2 forming the second row 2B.
• the refrigerant that has flowed through the multiple heat transfer tubes 2 forming the second row 2B joins at the second lower header 5 and flows out of the second refrigerant pipe 12.
• the pressure loss of the refrigerant flowing through the first lower header 4 in the longitudinal direction of the heat exchanger 1 is affected by the heat transfer tube 2 inserted into the first lower header 4.
• the degree of pressure loss of the refrigerant flowing from point P1 to point P2 varies depending on the insertion length of the heat transfer tube 2 into the first lower header 4.
• Point P1 is the point directly below the heat transfer tube 2 in the first row 2A that is closest to the first refrigerant piping 11.
• Point P2 is the point directly below the heat transfer tube 2 in the first row 2A that is furthest from the first refrigerant piping 11.
• the insertion length refers to the length by which the heat transfer tube 2 is inserted into the header.
• the pressure loss of the refrigerant flowing through the row header 6 in the short direction of the heat exchanger 1 is affected by the heat transfer tube 2 inserted into the row header 6. For this reason, for example, the pressure loss of the refrigerant flowing from point P3 to point P4 in the row header 6 varies depending on the insertion length of the heat transfer tube 2 into the row header 6.
• Point P3 is a point directly above the heat transfer tube 2 in the first row 2A that is the furthest from the first refrigerant pipe 11.
• Point P4 is a point directly above the heat transfer tube 2 in the second row 2B that is the furthest from the second refrigerant pipe 12. Note that the change in pressure loss depending on the insertion length is not limited to the section between points P3 and P4 that corresponds to the heat transfer tube 2 that is the furthest from the refrigerant pipe.
• the average insertion length tm1 of the multiple heat transfer tubes 2 inserted into the first lower header 4 is shorter than the average insertion length tm2 of the multiple heat transfer tubes 2 inserted into the row-over-row header 6.
• the average insertion length of the multiple heat transfer tubes 2 inserted into the second lower header 5 instead of the first lower header 4 may be shorter than the average insertion length tm2 of the multiple heat transfer tubes 2 inserted into the row-over-row header 6.
• the average insertion length of the multiple heat transfer tubes 2 inserted into both the first lower header 4 and the second lower header 5 may be shorter than the average insertion length tm2 of the multiple heat transfer tubes 2 inserted into the row-over-row header 6.
• the insertion length of the lower header is made smaller than the insertion length of the upper header, thereby limiting the insertion length of the heat transfer tube 2 inserted into the lower header so that it does not become excessively long.
• the change in cross-sectional area is reduced by reducing the amount of the heat transfer tube 2 inserted into the lower header. This reduces the pressure loss of the refrigerant flowing through the lower header.
• the insertion length of the lower header is made smaller than the insertion length of the upper header, thereby limiting the insertion length of the heat transfer tube 2 inserted into the upper header so that it does not become excessively short. This increases the pressure loss of the refrigerant flowing through the upper header.
• the amount of refrigerant distributed differs between the heat transfer tubes 2 close to the refrigerant piping that flows the refrigerant into the header and the heat transfer tubes 2 far from it.
• the pressure loss of the refrigerant flowing through the lower header is reduced, and the pressure loss of the refrigerant flowing through the upper header is increased. Therefore, in the first embodiment, the refrigerant that flows from the first refrigerant piping 11 to the lower header is less likely to flow from the lower header to the heat transfer tubes 2, but is more likely to flow to the back of the lower header (the part far from the first refrigerant piping 11).
• the amount of refrigerant flowing from the lower header toward the heat transfer tubes 2 inserted in a position close to the first refrigerant piping 11 is reduced compared to the embodiment in which the pressure loss of the lower header and the upper header is not adjusted as in the first embodiment. Then, the reduced amount of refrigerant flows into the back of the lower header, so the amount of refrigerant flowing toward the heat transfer tubes 2 inserted in a position far from the first refrigerant piping 11 increases. Therefore, in the lower header, the amount of refrigerant distributed can be made similar between the heat transfer tube 2 inserted at a position far from the first refrigerant pipe 11 and the heat transfer tube 2 inserted at a position close to the first refrigerant pipe 11.
• the insertion length of the lower header is shorter than the insertion length of the upper header. Therefore, even when a plurality of heat transfer tubes 2 are evenly arranged in the longitudinal direction, the heat exchanger 1 can distribute the refrigerant evenly between the heat transfer tubes 2 inserted at a position far from the first refrigerant pipe 11 and the heat transfer tubes 2 inserted at a position close to the first refrigerant pipe 11. Therefore, according to the heat exchanger 1 of embodiment 1, it is possible to improve the refrigerant distribution performance while suppressing a decrease in the workability of the header.
• Embodiment 2 differs from the first embodiment in that an upper limit is set for the insertion length of the heat transfer tubes 2 into the row-to-row header 6.
• the following mainly describes the parts that differ from the first embodiment, and the same reference numerals are used to denote the same or corresponding parts as in the first embodiment, and description thereof will be omitted.
• FIG. 5 is a diagram for explaining the upper limit of the insertion length of the heat transfer tube 2 according to the second embodiment.
• the distance between the upper inner wall surface 62a (the inner wall surface of the cover plate 62) constituting the upper part inside the row header 6 and the upper end of the heat transfer tube 2 is ⁇ .
• the distance between the upper inner wall surface 62a and the lower inner wall surface 61a (the bottom surface of the base 61) constituting the lower part inside the row header 6 is ⁇ y.
• ⁇ is the length obtained by subtracting the insertion length t2 from ⁇ y.
• ⁇ / ⁇ y ⁇ 0.75, and in particular, 0.6 ⁇ / ⁇ y ⁇ 0.75 is preferable.
• ⁇ may be the average distance between the multiple heat transfer tubes 2 and the upper inner wall surface 62a.
• FIG. 6 is a graph showing the relationship between ⁇ / ⁇ y and pressure loss.
• the first embodiment it has been explained that the amount of refrigerant distributed to the multiple heat transfer tubes 2 in the lower header can be made closer to uniform by restricting the insertion length of the heat transfer tubes 2 inserted into the row header 6 so that it is not excessively short.
• the slope of the pressure loss in the row header 6 becomes large when ⁇ / ⁇ y exceeds 0.75. If the pressure loss in the row header 6 becomes excessively large, the speed of the refrigerant flowing through the heat transfer tubes 2 may decrease drastically, and the heat exchange performance of the heat exchanger 1 may decrease.
• the second embodiment as described above, by setting ⁇ / ⁇ y ⁇ 0.75, it is possible to prevent the pressure loss from becoming excessively large and the heat exchange performance of the heat exchanger 1 from decreasing.
• the amount of refrigerant distributed can be made closer between the heat transfer tubes 2 inserted in a position far from the first refrigerant pipe 11 and the heat transfer tubes 2 inserted in a position close to the first refrigerant pipe 11 in the lower header.
• Fig. 7 is a cross-sectional view of a heat exchanger 1A according to embodiment 3.
• Fig. 7 shows a cross section of the heat exchanger 1A cut in the YZ plane.
• embodiment 3 differs from embodiment 1 in that an inner tube 7 is inserted inside the first lower header 4.
• the following mainly describes the parts that differ from embodiment 1, and the same reference numerals are used to denote the same or corresponding parts as embodiment 1, and description thereof will be omitted.
• the inner pipe 7 is a hollow cylinder with multiple orifices 71 formed therein.
• the internal space of the inner pipe 7 is connected to the internal space of the first refrigerant pipe 11, and the refrigerant flows into the inner pipe 7 through the first refrigerant pipe 11.
• the multiple orifices 71 are formed at intervals in the axial direction of the inner pipe 7.
• the inner pipe 7 may be provided in the second lower header 5 instead of the first lower header 4. Also, the inner pipe 7 may be provided in both the first lower header 4 and the second lower header 5.
• the third embodiment since the inner tube 7 is inserted into the lower header, it is possible to prevent the heat transfer tube 2 from being inserted too far into the lower header. In other words, by providing the inner tube 7 in the lower header, it is possible to improve the positioning of the heat transfer tube 2.
• Fig. 8 is a cross-sectional view of a heat exchanger 1B according to embodiment 4.
• Fig. 8 shows a cross section of the heat exchanger 1B cut in the YZ plane.
• embodiment 4 differs from embodiment 3 in that the insertion length of the heat transfer tubes 2 into the row header 6 is changed depending on the insertion position of the heat transfer tube 2.
• the following mainly describes the parts that differ from embodiment 3, and the same reference numerals are used to denote the same or corresponding parts as embodiment 3, and description thereof will be omitted.
• the heat transfer tubes 2 forming the first row 2A are inserted into the row header 6 so that their insertion length gradually decreases as they become farther from the first refrigerant pipe 11. Therefore, in the row header 6, the insertion length of the first heat transfer tube 2a inserted into a position close to the first refrigerant pipe 11 is longer than the insertion length of the second heat transfer tube 2b inserted into a position farther from the first refrigerant pipe 11 than the first heat transfer tube 2a.
• the first heat transfer tube 2a is, for example, the heat transfer tube 2 inserted into a position closest to the first refrigerant pipe 11 among the multiple heat transfer tubes 2.
• the second heat transfer tube 2b is, for example, the heat transfer tube 2 inserted into a position farthest from the first refrigerant pipe 11 among the multiple heat transfer tubes 2.
• the insertion length of the first heat transfer tube 2a may be longer than the insertion length of the second heat transfer tube 2b, so that the heat transfer tube 2 may come into contact with the inner tube 7.
• the inner tube 7 may be omitted.
• the multiple heat transfer tubes 2 forming the second row 2B may be inserted into the row header 6 so that the insertion length gradually decreases as the tubes become farther from the second refrigerant pipe 12.
• both the multiple heat transfer tubes 2 forming the first row 2A and the multiple heat transfer tubes 2 forming the second row 2B may be inserted into the row header 6 so that the insertion length gradually decreases as the tubes become farther from the second refrigerant pipe 12.
• the amount of refrigerant distributed between the heat transfer tube 2 inserted at a position far from the first refrigerant pipe 11 in the first lower header 4 and the heat transfer tube 2 inserted at a position close to the first refrigerant pipe 11 can be made closer.
• the insertion length of the heat transfer tubes 2 forming the second row 2B in the second lower header 5, not in the first lower header 4 may be gradually shortened as they become farther from the second refrigerant pipe 12.
• the insertion length of the heat transfer tubes 2 may be gradually shortened as they become farther from the first refrigerant pipe 11 or the second refrigerant pipe 12.
• the insertion length may be changed every several heat transfer tubes 2, rather than changing the insertion length for each heat transfer tube 2.
• an upper limit may be set for the insertion length of the heat transfer tubes 2 into the row header 6, as described in embodiment 2.
• the heat transfer tubes 2 form the first row 2A and the second row 2B has been described, but the second row 2B of the heat transfer tubes 2 and the second lower header 5 may be omitted.
• the row-to-row header 6 is provided with the second refrigerant pipe 12 and functions as a header that causes the refrigerant that has joined from the first row 2A to flow out to the second refrigerant pipe 12.
• the heat transfer tubes 2 may be tubes of other shapes, such as circular tubes.
• 1, 1A, 1B heat exchanger 2 heat transfer tube, 2A first row, 2B second row, 2a first heat transfer tube, 2b second heat transfer tube, 3 fin, 4 first lower header, 5 second lower header, 6 row header, 7 inner tube, 11 first refrigerant piping, 12 second refrigerant piping, 61 base, 61a lower inner wall surface, 62 cover plate, 62a upper inner wall surface, 71 orifice, 100 air conditioning device, 110 outdoor unit, 111 compressor, 112 flow path switching valve, 113 blower, 114 expansion valve, 120 indoor unit, 121 heat exchanger, 122 blower, 130 refrigerant piping.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

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Citations (9)

• 2024
  • 2024-01-19 JP JP2025570477A patent/JPWO2025154256A1/ja active Pending
  • 2024-01-19 WO PCT/JP2024/001389 patent/WO2025154256A1/ja active Pending

Patent Citations (9)

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