JP2019011923A - Heat exchanger - Google Patents

Abstract

To provide a heat exchanger which easily secures the pressure resistance of flat porous pipes while sufficiently exerting performance at both a windward side and a leeward side in an airflow direction even in the case for retarding an increase of ventilation resistance caused by the adhesion of frost.SOLUTION: A heat exchanger comprises: flat porous pipes 63 having a plurality of passage 63b which are aligned in an airflow direction; and fins 64 having communication parts 64x in which the flat porous pipes 63 are inserted into and fixed to notches 64a which are notched toward a windward side from a leeward side in the airflow direction, and which are vertically connected to each other on the windward side of the flat porous pipes 63. Relationships of 0.18≤L/Wt≤0.32 and 2≤a/b≤16 are satisfied. Here, L: a distance from windward ends of the flat porous pipes 63 up to windward ends of the fins 64, Wt: a length in the airflow direction of the flat porous pipes 63, a: a total value of widths in the airflow directions of first and second passages 63b from the windward side of the flat porous pipes 63, and b: a width in the airflow direction of the passage 63b at a center in the airflow direction of the flat porous pipes 63.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a heat exchanger.

  Conventionally, heat exchange is provided with a plurality of flat multi-hole tubes and fins joined to the plurality of flat multi-hole tubes, and exchanges heat between the refrigerant flowing inside the flat multi-hole tubes and the air flowing outside the flat multi-hole tubes. The vessel is known.

  For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-139282) proposes a heat exchanger in which a notch is formed in a fin from the leeward side toward the leeward side, and a flat multi-hole tube is inserted and fixed from the leeward side of the fin. Has been.

  In the heat exchanger shown in Patent Document 1, fins are not provided on the windward side of the windward end of the flat multi-hole tube. For this reason, when a heat exchanger is used as an evaporator having a low evaporation temperature in an environment where the outside air temperature is low, frost is concentrated on the fins of the heat exchanger and the windward portion of the flat multi-hole tube. Therefore, the increase in ventilation resistance tends to occur early. For this reason, it will be necessary to perform the operation | movement etc. for melting the frost adhering to a heat exchanger frequently.

  On the other hand, by providing fins further on the windward side than the windward end of the flat multi-hole tube, it is possible to alleviate the state where frost is concentrated on the windward side portion of the flat multi-hole tube. .

  However, when fins are provided further on the windward side than the windward end of the flat multi-hole tube in this way, the airflow direction is not correct due to the larger difference between the air temperature and the refrigerant temperature on the windward side. In addition to the balance, the amount of heat flux from the fins for the refrigerant channel on the windward side among the plurality of refrigerant channels provided in the flat multi-hole tube is larger than the amount of heat flux for the refrigerant channel on the leeward side. As a result, an imbalance in the air flow direction occurs. When this imbalance occurs, the refrigerant flowing in the refrigerant channel on the leeward side of the flat multi-hole tube will evaporate in the middle of the channel, but the refrigerant flowing in the refrigerant channel on the leeward side will be sufficiently evaporated. There is a possibility that the performance of the heat exchanger cannot be fully exhibited.

  The present invention has been made in view of the above points, and the object of the present invention is sufficient on both the leeward side and the leeward side in the air flow direction even when the increase in ventilation resistance due to frost adhesion is delayed. An object of the present invention is to provide a heat exchanger that can easily ensure the pressure-resistant strength of a flat multi-hole tube while exhibiting performance.

  The heat exchanger according to the first aspect includes a flat multi-hole tube and a fin. The flat multi-hole tube has a plurality of refrigerant channels arranged in the air flow direction. A flat multi-hole tube is inserted and fixed at a location where the fin is cut out from the leeward side toward the leeward side in the air flow direction. The fin has a portion connected up and down on the windward side of the flat multi-hole tube. L: distance in the air flow direction from the wind upper end of the flat multi-hole tube to the wind upper end of the fin, Wt: length of the flat multi-hole tube in the air flow direction, a: first and second from the windward side of the flat multi-hole tube 0.18 ≦ L / Wt ≦ when the total value of the width of the refrigerant flow path in the air flow direction, b: the width of the refrigerant flow path in the center of the flat multi-hole tube in the air flow direction, 0.32 and 2 ≦ a / b ≦ 16 is satisfied.

  As for “b”, when there is no refrigerant flow path in the center of the flat multi-hole tube (for example, there is a partition for partitioning each refrigerant flow path), the width of the nearest refrigerant flow path from the center. It may also be an average value of the widths of the two refrigerant channels sandwiching the center.

  It should be noted that the average length in the air flow direction of each refrigerant flow channel located on the windward side of each refrigerant flow channel located on the leeward side of each refrigerant flow channel located on the leeward side including the center of the flat multi-hole tube is It is preferable that it is larger.

  In this heat exchanger, the fin has a portion connected up and down on the windward side of the flat multi-hole tube, and 0.18 ≦ L / Wt for the portion on the windward side of the flat multi-hole tube of the fin. Therefore, a wide frostable area is ensured, and the frosting resistance can be improved. For this reason, it is possible to eliminate the need for frequent defrosting and operation performed to melt the frost attached to the heat exchanger. Moreover, since it is comprised so that the relationship of L / Wt <= 0.32 may be satisfy | filled about the part on the windward side from the flat multi-hole tube of a fin, the unnecessary part which is hard to contribute to the improvement of frost proof stress is reduced. This makes it possible to reduce the material cost of the fins.

  Here, the temperature difference between the air passing outside the flat multi-hole tube and the refrigerant passing through the refrigerant flow path of the flat multi-hole tube tends to be larger on the leeward side in the air flow direction than on the leeward side. . For this reason, in a plurality of refrigerant flow paths provided side by side in the air flow direction in the flat multi-hole tube, the amount of heat exchange tends to be larger on the windward side of the airflow than on the leeward side. In the structure in which the fins are positioned on the windward side of the flat multi-hole tube in order to improve the frosting resistance as described above, with respect to the windward side portion of the plurality of refrigerant channels of the flat multi-hole tube. Further, since the heat flux from the fin located on the leeward side is supplied, the amount of heat exchange in the refrigerant channel on the leeward side of the airflow tends to be larger than that on the leeward side refrigerant channel. .

  Even in such a structure, this heat exchanger has a structure satisfying the relationship of 2 ≦ a / b, so that the refrigerant channel on the leeward side of the refrigerant channel of the flat multi-hole tube is connected to the refrigerant flow on the windward side. The refrigerant channel on the windward side is made larger in the refrigerant channel of the flat multi-hole tube without making it larger than the path so as to correspond to the amount of heat flux supplied from the surrounding fins. Thereby, the performance of the heat exchanger can be improved. It is more preferable to satisfy the relationship of 2.5 ≦ a / b.

  In such a structure, the heat exchanger has a structure satisfying the relationship of a / b ≦ 16, so that the size of the relatively large refrigerant flow path on the windward side of the flat multi-hole tube in the air flow direction. Comparison of the upwind side of a flat multi-hole tube by ensuring that it does not become too large (by ensuring that the size in the air flow direction is not excessive relative to the length in the direction perpendicular to the air flow direction) It is easy to ensure pressure resistance even in a large refrigerant flow path.

  As described above, while adopting a structure that delays the increase in ventilation resistance due to the adhesion of frost, the performance of both the refrigerant channel on the windward side and the refrigerant channel on the leeward side in the air flow direction of the flat multi-hole tube is sufficient. It is possible to ensure the pressure resistance of the flat multi-hole tube while exhibiting it.

  The heat exchanger according to the second aspect is the heat exchanger according to the first aspect, and satisfies the relationship of 0.21 ≦ L / Wt ≦ 0.32. The leeward end of the fin is located further on the leeward side in the air flow direction than that of the flat multi-hole tube.

  In this heat exchanger, it is possible to more reliably improve the frosting resistance by securing a portion of the fin that is on the windward side of the flat multi-hole tube. Furthermore, since the lee end of the fin is located further on the leeward side in the air flow direction than the lee end of the flat multi-hole tube, the condensed water is lowered from the leeward lower end of the fin protruding to the leeward side. It is possible to improve the drainage efficiency of the condensed water.

  The heat exchanger which concerns on a 3rd viewpoint is a heat exchanger which concerns on a 2nd viewpoint, Comprising: The lee end of a fin is located in the leeward side further 2 mm or more away from the lee end of a flat multi-hole pipe.

  In general, in a structure in which condensed water is supplied to the wind lower end of the fin, when frost adheres to the wind lower end of the fin of the heat exchanger, the frost may grow.

  On the other hand, in this heat exchanger, the lee end of the fin is positioned further 2 mm or more away from the lee side of the flat multi-hole tube. For this reason, the dew condensation water that flows down from the wind lower end of the flat multi-hole tube is difficult to be supplied to the wind lower end of the fin, and it is possible to suppress the growth of frost at the wind lower end of the fin.

  The heat exchanger according to the fourth aspect is a heat exchanger according to the first aspect, and satisfies a relationship of 0.18 ≦ L / Wt ≦ 0.30. The lower end of the flat multi-hole tube is located further on the leeward side in the air flow direction than the lower end of the fin.

  Since this heat exchanger is configured to satisfy the relationship of L / Wt ≦ 0.30 for the portion on the windward side of the flat multi-hole tube of the fin, it is unnecessary to contribute to the improvement of the frosting resistance. By sufficiently reducing the portion, it is possible to sufficiently suppress the material cost of the fins.

  Further, in this heat exchanger, the flat multi-hole tube is positioned on the leeward side in the air flow direction further than the fin lower end, so that the flat multi-hole tube protrudes leeward rather than the fin. Thus, it is possible to protect the leeward side of the fin during manufacturing or transportation.

  In addition, by adopting a configuration in which a flat multi-hole tube is projected to the leeward side instead of a fin, for example, when bending a heat exchanger, a tool is pressed against the flat multi-hole tube to work. It is possible to suppress deformation and damage of the leeward fin. Further, when brazing in the furnace, the flat multi-hole tube, not the fins, can be grounded, and it is possible to suppress thermal contraction and deformation of the fins caused by the grounding of the fins.

  A heat exchanger according to a fifth aspect is a heat exchanger according to any one of the first to fourth aspects, and satisfies a relationship of 3 ≦ a / b ≦ 9.

  In this heat exchanger, by having a structure satisfying the relationship of 3 ≦ a / b, the refrigerant channel on the windward side of the refrigerant channel of the flat multi-hole tube is configured to be sufficiently large, so that the surrounding fins It is possible to improve the performance of the heat exchanger in accordance with the amount of heat flux supplied.

  Furthermore, in such a structure, in this heat exchanger, by satisfying the relationship of a / b ≦ 9, the size of the relatively large refrigerant flow path on the windward side of the flat multi-hole tube in the air flow direction Comparison of the upwind side of a flat multi-hole tube by ensuring that it does not become too large (by ensuring that the size in the air flow direction is not excessive relative to the length in the direction perpendicular to the air flow direction) It is easy to ensure sufficient pressure resistance even in a large refrigerant flow path.

  A heat exchanger according to a sixth aspect is the heat exchanger according to any one of the first to fifth aspects, and L ≧ 4 mm.

  In this heat exchanger, it is possible to improve the frosting resistance more reliably by securing sufficiently wide fins located on the windward side than the flat multi-hole tube.

  A heat exchanger according to a seventh aspect is the heat exchanger according to any one of the first to sixth aspects, wherein the width in the air flow direction of the refrigerant channel on the windward side of the flat multi-hole tube is flat. It is 1.5 times or more of the width in the air flow direction of the refrigerant flow path in the center of the air flow direction of the multi-hole tube, and preferably 2 times or more.

  In this heat exchanger, not only does the temperature difference between the refrigerant and the air tend to be larger on the windward side in the air flow direction, but the fins may spread on the windward side than the flat multi-hole tube, A large heat flux is supplied in the refrigerant flow path. Even with such a structure, it is possible to sufficiently exhibit the performance of the heat exchanger by sufficiently ensuring the size of the airflow direction of the most upstream refrigerant flow path.

  In the heat exchanger according to the first aspect, while adopting a structure that delays the increase in ventilation resistance due to adhesion of frost, an upwind refrigerant channel and a leeward refrigerant channel in the air flow direction of the flat multi-hole tube It is possible to ensure the pressure-resistant strength of the flat multi-hole tube while sufficiently exhibiting the performance of both.

  In the heat exchanger which concerns on a 2nd viewpoint, it becomes possible to improve the drainage efficiency of condensed water, improving frosting yield strength more reliably.

  In the heat exchanger according to the third aspect, the condensed water that flows down from the wind bottom end of the flat multi-hole tube is difficult to be supplied to the wind bottom end of the fin, and frost growth at the wind bottom end of the fin can be suppressed.

  In the heat exchanger which concerns on a 4th viewpoint, it becomes possible to protect the leeward side location of a fin at the time of manufacture or at the time of conveyance, fully suppressing the material cost of a fin.

  In the heat exchanger which concerns on a 5th viewpoint, it is easy to ensure sufficient pressure-resistant intensity | strength also in the comparatively big refrigerant | coolant flow path of the windward side of a flat multi-hole pipe | tube, improving the performance of a heat exchanger.

  In the heat exchanger according to the sixth aspect, it is possible to improve the frosting resistance more reliably by securing sufficiently wide fins located on the windward side than the flat multi-hole tube.

  In the heat exchanger which concerns on a 7th viewpoint, it becomes possible to fully exhibit the performance of a heat exchanger.

It is a schematic block diagram of the air conditioning apparatus by which the heat exchanger which concerns on one Embodiment of this invention was employ | adopted. It is an external appearance perspective view of an outdoor unit. It is a front view of an outdoor unit (shown excluding refrigerant circuit components other than the outdoor heat exchanger). It is a schematic perspective view of an outdoor heat exchanger. It is the elements on larger scale of the heat exchange part of FIG. It is the schematic which shows the attachment state with respect to the flat multi-hole pipe of a fin. It is a block diagram for demonstrating the refrigerant | coolant flow of an outdoor heat exchanger. It is the schematic which shows the attachment state with respect to the flat multi-hole pipe of the fin which concerns on the modification A. It is the schematic which shows the attachment state with respect to the flat multi-hole tube of the fin which concerns on the modification B. It is the schematic which shows the attachment state with respect to the flat multi-hole pipe of the fin which concerns on the modification C.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an air-conditioning apparatus in which an outdoor heat exchanger as a heat exchanger according to the present invention is employed and modifications thereof will be described with reference to the drawings. In addition, the specific structure of the outdoor heat exchanger as a heat exchanger which concerns on this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) Configuration of Air Conditioner FIG. 1 is a schematic configuration diagram of an air conditioner 1 that employs an outdoor heat exchanger 11 as a heat exchanger according to an embodiment of the present invention.

  The air conditioner 1 is a device capable of cooling and heating a room such as a building by performing a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2, indoor units 3a and 3b, a liquid refrigerant communication tube 4 and a gas refrigerant communication tube 5 that connect the outdoor unit 2 and the indoor units 3a and 3b, an outdoor unit 2 and And a control unit 23 that controls the constituent devices of the indoor units 3a and 3b. The vapor compression refrigerant circuit 6 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor units 3 a and 3 b via the refrigerant communication tubes 4 and 5.

  The outdoor unit 2 is installed outdoors (on the roof of a building, in the vicinity of the wall surface of the building, etc.) and constitutes a part of the refrigerant circuit 6. The outdoor unit 2 mainly includes an accumulator 7, a compressor 8, a four-way switching valve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12 as an expansion mechanism, a liquid side shut-off valve 13, and a gas side shut-off valve. 14 and an outdoor fan 15. Each device and the valve are connected by refrigerant pipes 16 to 22.

  The indoor units 3 a and 3 b are installed indoors (such as a living room or a ceiling space) and constitute a part of the refrigerant circuit 6. The indoor unit 3a mainly has an indoor expansion valve 31a, an indoor heat exchanger 32a, and an indoor fan 33a. The indoor unit 3b mainly includes an indoor expansion valve 31b as an expansion mechanism, an indoor heat exchanger 32b, and an indoor fan 33b.

  The refrigerant communication pipes 4 and 5 are refrigerant pipes that are constructed on site when the air conditioner 1 is installed at an installation location such as a building. One end of the liquid refrigerant communication tube 4 is connected to the liquid side closing valve 13 of the outdoor unit 2, and the other end of the liquid refrigerant communication tube 4 is connected to the liquid side ends of the indoor expansion valves 31a and 31b of the indoor units 3a and 3b. Has been. One end of the gas refrigerant communication pipe 5 is connected to the gas side shut-off valve 14 of the outdoor unit 2, and the other end of the gas refrigerant communication pipe 5 is connected to the gas side end of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b. It is connected.

  The control unit 23 is configured by communication connection of control boards and the like (not shown) provided in the outdoor unit 2 and the indoor units 3a and 3b. In FIG. 1, for the sake of convenience, the outdoor unit 2 and the indoor units 3a and 3b are illustrated at positions away from each other. The control unit 23 controls the components 8, 10, 12, 15, 31a, 31b, 33a, 33b of the air conditioner 1 (here, the outdoor unit 2 and the indoor units 3a, 3b), that is, the air conditioner 1 The whole operation control is performed.

(2) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 is demonstrated using FIG. In the air conditioner 1, in the cooling operation in which the refrigerant flows in the order of the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, the indoor expansion valves 31a and 31b, and the indoor heat exchangers 32a and 32b, the compressor 8, the indoor heat A heating operation is performed in which the refrigerant flows in the order of the exchangers 32a and 32b, the indoor expansion valves 31a and 31b, the outdoor expansion valve 12, and the outdoor heat exchanger 11. The cooling operation and the heating operation are performed by the control unit 23.

  During the cooling operation, the four-way switching valve 10 is switched to the outdoor heat dissipation state (the state shown by the solid line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the outdoor heat exchanger 11 through the four-way switching valve 10. The high-pressure gas refrigerant sent to the outdoor heat exchanger 11 dissipates heat by exchanging heat with outdoor air supplied as a cooling source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant radiator. Become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has radiated heat in the outdoor heat exchanger 11 is sent to the indoor expansion valves 31 a and 31 b through the outdoor expansion valve 12, the liquid-side closing valve 13, and the liquid refrigerant communication pipe 4. The refrigerant sent to the indoor expansion valves 31a and 31b is decompressed to the low pressure of the refrigeration cycle by the indoor expansion valves 31a and 31b, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the indoor expansion valves 31a and 31b is sent to the indoor heat exchangers 32a and 32b. The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with indoor air supplied as a heating source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Evaporate. As a result, the room air is cooled and then supplied to the room to cool the room. The low-pressure gas refrigerant evaporated in the indoor heat exchangers 32 a and 32 b is again sucked into the compressor 8 through the gas refrigerant communication pipe 5, the gas-side closing valve 14, the four-way switching valve 10, and the accumulator 7.

  During the heating operation, the four-way selector valve 10 is switched to the outdoor evaporation state (the state indicated by the broken line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the indoor heat exchangers 32 a and 32 b through the four-way switching valve 10, the gas-side closing valve 14, and the gas refrigerant communication pipe 5. The high-pressure gas refrigerant sent to the indoor heat exchangers 32a and 32b dissipates heat by exchanging heat with indoor air supplied as a cooling source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Becomes a high-pressure liquid refrigerant. Thereby, indoor air is heated, and indoor heating is performed by being supplied indoors after that. The high-pressure liquid refrigerant radiated by the indoor heat exchangers 32 a and 32 b is sent to the outdoor expansion valve 12 through the indoor expansion valves 31 a and 31 b, the liquid refrigerant communication tube 4 and the liquid-side closing valve 13. The refrigerant sent to the outdoor expansion valve 12 is decompressed to the low pressure of the refrigeration cycle by the outdoor expansion valve 12, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the outdoor expansion valve 12 is sent to the outdoor heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant sent to the outdoor heat exchanger 11 exchanges heat with outdoor air supplied as a heating source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant evaporator. Go and evaporate into a low-pressure gas refrigerant. The low-pressure refrigerant evaporated in the outdoor heat exchanger 11 is again sucked into the compressor 8 through the four-way switching valve 10 and the accumulator 7.

  In the state where the outdoor heat exchanger 11 functions as the refrigerant evaporator during the heating operation, if the outdoor air temperature or the refrigerant evaporation temperature satisfies a predetermined operating condition, the outdoor heat exchanger 11 is frosted. May adhere. If a lot of the frost adheres, the air supplied from the outdoor fan 15 receives excessive ventilation resistance when passing through the outdoor heat exchanger 11 to which the frost has adhered, and the heat exchange efficiency decreases. There is a risk that. Therefore, when a predetermined defrost determination condition such as a state where the predetermined operating condition is satisfied for a predetermined time or longer is satisfied, the control unit 23 causes the four-way switching valve 10 to move to the outdoor heat dissipation state (indicated by the solid line in FIG. 1). Switch to the state shown) and perform defrost operation. When the defrost process is completed, for example, when the defrost operation is performed for a predetermined time, the control unit 23 switches the four-way switching valve 10 to the outdoor evaporation state (the state indicated by the broken line in FIG. 1) again to perform the heating operation. To resume.

(3) Configuration of Outdoor Unit FIG. 2 is an external perspective view of the outdoor unit 2. FIG. 3 is a front view of the outdoor unit 2 (illustrated excluding refrigerant circuit components other than the outdoor heat exchanger 11). FIG. 4 is a schematic perspective view of the outdoor heat exchanger 11. FIG. 5 is a partially enlarged view of the heat exchange unit 60 of FIG. FIG. 6 is a schematic view showing a state in which the fin 64 is attached to the flat multi-hole tube 63. FIG. 7 is a configuration diagram for explaining a refrigerant flow in the outdoor heat exchanger 11.

(3-1) Overall Configuration The outdoor unit 2 is a top-blow-type heat exchange unit that sucks air from the side surface of the casing 40 and blows air from the top surface of the casing 40. The outdoor unit 2 mainly includes a substantially rectangular parallelepiped box-shaped casing 40, an outdoor fan 15 as a blower, devices 7, 8, 11 such as a compressor and an outdoor heat exchanger, a four-way switching valve, an outdoor expansion valve, and the like. And refrigerant circuit components that constitute a part of the refrigerant circuit 6 including the valves 10, 12 to 14, the refrigerant pipes 16 to 22, and the like. In the following description, “top”, “bottom”, “left”, “right”, “front”, “back”, “front”, and “back” are shown in FIG. 2 unless otherwise specified. The direction when the outdoor unit 2 to be viewed is viewed from the front (left oblique front side of the drawing) is meant.

  The casing 40 mainly includes a bottom frame 42 that spans a pair of installation legs 41 that extend in the left-right direction, a column 43 that extends vertically from a corner of the bottom frame 42, and a fan module 44 that is attached to the upper end of the column 43. And a front panel 45. Air inlets 40a, 40b, 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and an air outlet 40d is formed on the top surface.

  The bottom frame 42 forms the bottom surface of the casing 40, and the outdoor heat exchanger 11 is provided on the bottom frame 42. Here, the outdoor heat exchanger 11 is a substantially U-shaped heat exchanger in plan view facing the back surface and both left and right side surfaces of the casing 40, and substantially forms the back surface and both left and right side surfaces of the casing 40. .

  A fan module 44 is provided on the upper side of the outdoor heat exchanger 11, and forms a portion above the front and rear surfaces of the casing 40, the left and right support columns 43, and the top surface of the casing 40. . Here, the fan module 44 is an assembly in which the outdoor fan 15 is accommodated in a substantially rectangular parallelepiped box having an upper surface and a lower surface opened. The opening on the top surface of the fan module 44 is an air outlet 40d, and an air outlet grill 46 is provided at the air outlet 40d. The outdoor fan 15 is disposed in the casing 40 so as to face the air outlet 40d, and is a blower that takes air into the casing 40 from the suction ports 40a, 40b, and 40c and discharges it from the air outlet 40d.

  The front panel 45 is spanned between the support columns 43 on the front side, and forms the front surface of the casing 40.

  In the casing 40, refrigerant circuit components other than the outdoor fan 15 and the outdoor heat exchanger 11 (accumulator 7, compressor 8, and refrigerant pipes 16 to 18 are shown in FIG. 2) are also housed. Here, the compressor 8 and the accumulator 7 are provided on the bottom frame 42.

  Thus, the outdoor unit 2 includes a casing 40 in which air inlets 40a, 40b, and 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and an air outlet 40d is formed on the top surface. It has the outdoor fan 15 arrange | positioned facing the blower outlet 40d in the inside, and the outdoor heat exchanger 11 arrange | positioned in the casing 40 under the outdoor fan 15 inside. In such a top-blow type unit configuration, the outdoor heat exchanger 11 is disposed below the outdoor fan 15, and therefore the wind speed of the air passing through the outdoor heat exchanger 11 is different from that of the outdoor heat exchanger 11. The upper part tends to be faster than the lower part of the outdoor heat exchanger 11.

(3-2) Outdoor heat exchanger The outdoor heat exchanger 11 is a heat exchanger that performs heat exchange between the refrigerant and the outdoor air, and mainly includes a first header collecting pipe 80, a second header collecting pipe 90, A plurality of flat multi-hole tubes 63 and a plurality of fins 64 are provided. Here, all of the first header collecting pipe 80, the second header collecting pipe 90, the flat multi-hole pipe 63 and the fin 64 are formed of aluminum or an aluminum alloy, and are joined to each other by brazing or the like.

  Each of the first header collecting pipe 80 and the second header collecting pipe 90 is a vertically long hollow cylindrical member. The first header collecting pipe 80 is erected on one end side of the outdoor heat exchanger 11 (here, the left front end side in FIG. 4), and the second header collecting pipe 90 is the other end of the outdoor heat exchanger 11. It is erected on the side (here, the right front end side in FIG. 4).

(4) Flat multi-hole tube The flat multi-hole tube 63 is a flat multi-hole tube having a flat surface 63a on an upper surface and a lower surface facing the vertical direction as a heat transfer surface, and a large number of small passages 63b through which a refrigerant flows. The plurality of passages 63b included in the flat multi-hole tube 63 are provided side by side along the air flow direction (longitudinal direction in a cross-sectional view of the passage 63b). In the present embodiment, the flat multi-hole pipe 63 has a uniform vertical width, and the passage 63b has a uniform vertical width. The plurality of passages 63b are different in size, and are configured such that the flow passage area is larger as the passage is located on the windward side. More specifically, the flat multi-hole pipe 63 of the present embodiment is configured such that the width in the air flow direction of the passage 63b located on the furthest side is the width a1, The passage 63b is configured such that the width in the air flow direction is the width a2, and the relation of width a1> width a2 is satisfied (in this embodiment, the length Wt of the flat multi-hole pipe 63 in the air flow direction). The width b of the passage 63b located at the center of the center is the same as the width a2.) When the total value a = a1 + a2 of the width in the air flow direction of the first and second passages 63b from the windward side in the flat multi-hole tube 63 is set to satisfy the relationship 2 ≦ a / b ≦ 16. Has been. The relationship is more preferably a relationship satisfying 3 ≦ a / b ≦ 9.

  The width a1 in the air flow direction of the windward passage 63b of the flat multi-hole tube 63 is 1.5 times or more the width b in the air flow direction of the center passage 63b of the flat multi-hole tube 63. It is preferable that the number is twice or more.

  In addition, although it does not specifically limit about the part which divides between each channel | path 63b of the flat multi-hole pipe 63, Each may have the same width | variety in an air flow direction.

  The flat multi-hole tube 63 is not particularly limited, but is manufactured by, for example, extrusion molding.

  A plurality of flat multi-hole tubes 63 are arranged in the vertical direction at a predetermined interval (between centers in the height direction: a predetermined pitch Tp). Although not particularly limited, for example, the relationship between the vertical thickness Tt of the flat multi-hole tube 63 and the predetermined pitch Tp satisfies the relationship of Tp = 5 Tt to 9 Tt (more preferably Tp = 6 Tt to 8 Tt). It is preferable that the flat multi-hole pipes 63 are densely arranged in the vertical direction. Here, when the predetermined pitch Tp is too short, there is a problem of an increase in ventilation resistance due to a narrow space between the flat multi-hole pipes 63 and an increase in cost due to an increase in the number of flat multi-hole pipes 63. Arise. Further, if the predetermined pitch Tp is too long, a portion of the fin 64 that is far away from the flat multi-hole tube 63 becomes large, so that there is a problem that the heat transfer efficiency in the fin 64 decreases. Further, when the thickness Tt of the flat multi-hole tube 63 is too large, the refrigerant passage area of the passage 63b becomes too large, and the flow rate of the refrigerant in the passage 63b decreases, so that the heat transfer coefficient in the tube In which the flow resistance of the flat multi-hole pipe 63 in the flow direction crossing the flat multi-hole pipe 63 (dead water area) ) Increases, the heat transfer efficiency of the fins 64 decreases, and the cost increases due to an increase in the wall thickness to ensure the pressure resistance accompanying the increase in the size of the flat multi-hole tube 63 In addition, there is a problem that the amount of refrigerant increases due to an increase in the refrigerant passage area in the passage 63b. Further, when the thickness Tt of the flat multi-hole tube 63 is too small, there is a problem that the pressure loss received by the refrigerant increases due to the refrigerant passage area of the passage 63b being reduced. Considering the above matters, the relationship between the thickness Tt of the flat multi-hole tube 63 and the predetermined pitch Tp preferably satisfies the above-described relationship.

  In the flat multi-hole pipe 63, both ends of each passage 63b are connected to the first header collecting pipe 80 and the second header collecting pipe 90.

(5) Fins The fins 64 are plate-like members extending in the air flow direction and the vertical direction, and a plurality of fins 64 are arranged at predetermined intervals in the plate thickness direction, and are fixed to the flat multi-hole tube 63. The fin 64 is formed with a plurality of cutout portions 64a that are cut in the horizontal direction from the edge on the leeward side toward the windward side and before the edge on the windward side. The shape of the cutout portion 64a substantially matches the outer shape of the cross section of the flat multi-hole tube 63, and is brazed and fixed to the cutout portion 64a in a state where the flat multi-hole tube 63 is inserted.

  The fin 64 has a communication portion 64x that is continuous in the vertical direction on the windward side of the flat multi-hole tube 63 on the windward side. Here, the distance L in the air flow direction from the wind upper end of the flat multi-hole tube 63 to the wind upper end of the communication portion 64x of the fin 64 and the length Wt of the flat multi-hole tube 63 in the air flow direction are 0.18. ≦ L / Wt ≦ 0.32 is satisfied. The relationship is more preferably a relationship satisfying 0.21 ≦ L / Wt ≦ 0.32. Further, the distance L satisfies the relationship of L ≧ 4 mm from the viewpoint of ensuring a sufficiently wide portion located on the windward side of the flat multi-hole tube 63 of the fin 64 and improving the frosting resistance more reliably. More preferred.

  The fin 64 has a leeward projecting portion 64 y that projects further toward the leeward side than the leeward side end portion of the flat multi-hole tube 63. That is, the length of the notch 64a of the fin 64 in the air flow direction (the length Wf of the fin 64 in the air flow direction−the distance L) is larger than the width Wt of the flat multi-hole tube 63 in the air flow direction. It is configured. Here, the distance Q in the air flow direction from the wind lower end of the flat multi-hole tube 63 to the wind lower end of the leeward protrusion 64y of the fin 64 is configured to be 2 mm or more. The upper limit of the distance Q is not particularly limited, but can be 5 mm, for example, in order to reduce the material cost of the fins 64.

(6) Other Configurations of Outdoor Heat Exchanger The outdoor heat exchanger 11 has a heat exchanging unit 60 configured by fixing fins 64 to flat multi-hole pipes 63 arranged in the vertical direction. The heat exchange unit 60 includes an upper stage upper heat exchange unit 60A and a lower stage lower heat exchange unit 60B.

  The first header collecting pipe 80 is vertically partitioned by a partition plate 81 whose horizontal space extends in the horizontal direction, so that the gas side inlet / outlet communication space corresponds to the upper heat exchange section 60A and the lower heat exchange section 60B. 80A and a liquid side inlet / outlet communication space 80B are formed. And the flat multi-hole pipe 63 which comprises the corresponding upper stage heat exchange part 60A is connecting to 80 A of gas side inlet-and-outlet communication spaces. In addition, a flat multi-hole pipe 63 constituting a corresponding lower heat exchange section 60B communicates with the liquid side inlet / outlet communication space 80B.

  In addition, a refrigerant pipe 19 (see FIG. 1) for sending the refrigerant sent from the compressor 8 during the cooling operation to the gas side inlet / outlet communication space 80A is connected to the gas side inlet / outlet communication space 80A of the first header collecting pipe 80. .

  In addition, a refrigerant pipe 20 (see FIG. 1) for sending the refrigerant sent from the outdoor expansion valve 12 during the heating operation to the liquid side inlet / outlet communication space 80B is connected to the liquid side inlet / outlet communication space 80B of the first header collecting pipe 80. Yes.

  The second header collecting pipe 90 is divided into partitions with nozzles provided between the partition plate 92 and the partition plate 93 while being partitioned vertically by partition plates 91, 92, 93, 94 whose internal space is expanded in the horizontal direction. By being divided vertically by the plate 99, first to third upper folded communication spaces 90A, 90B, 90C and first to third lower folded communication spaces 90D, 90E, 90F arranged in order from the upper side are formed. ing. The flat multi-hole pipe 63 in the corresponding upper heat exchange section 60A communicates with the first to third upper folded communication spaces 90A, 90B, 90C, and the first to third lower folded communication spaces 90D, 90E, 90F. Is connected to the flat multi-hole pipe 63 in the corresponding lower heat exchange section 60B. The third upper-stage folded communication space 90C and the first lower-stage folded communication space 90D are partitioned vertically by a partition plate 99 with nozzles, but a nozzle 99a provided so as to penetrate vertically in the partition plate 99 with nozzles is provided. Via the top and bottom. In addition, the first upper-stage folded communication space 90A and the third lower-stage folded communication space 90F are connected via the first connection pipe 24 connected to the second header collecting pipe 90, and the second upper-stage folded communication space 90F. 90B and the second lower folded communication space 90E are connected via a second connection pipe 25 connected to the second header collecting pipe 90.

  With the above configuration, when the outdoor heat exchanger 11 functions as a refrigerant evaporator, the refrigerant that has flowed from the refrigerant pipe 20 into the liquid side inlet / outlet communication space 80B of the first header collecting pipe 80 flows into the liquid side inlet / outlet communication space. It flows through the flat multi-hole tube 63 of the lower heat exchange section 60B connected to 80B and flows into the first to third lower folded communication spaces 90D, 90E, 90F of the second header collecting tube 90. The refrigerant that has flowed into the first lower folded communication space 90D flows into the third upper folded communication space 90C via the nozzle 99a of the partition plate 99 with nozzle, and is connected to the third upper folded communication space 90C. It flows into the gas side inlet / outlet communication space 80A of the first header collecting pipe 80 via the flat multi-hole pipe 63 of the portion 60A. The refrigerant that has flowed into the second lower folded communication space 90E flows into the second upper folded communication space 90B through the second connection pipe 25, and is connected to the second upper folded communication space 90B. The gas flows into the gas side inlet / outlet communication space 80 </ b> A of the first header collecting pipe 80 through the flat multi-hole pipe 63. The refrigerant that has flowed into the third lower folded communication space 90F flows into the first upper folded communication space 90A via the first connection pipe 24, and is connected to the first upper folded communication space 90A. The gas flows into the gas side inlet / outlet communication space 80 </ b> A of the first header collecting pipe 80 through the flat multi-hole pipe 63. The refrigerant merged in the gas side inlet / outlet communication space 80 </ b> A of the first header collecting pipe 80 flows to the outside of the outdoor heat exchanger 11 through the refrigerant pipe 19. When the outdoor heat exchanger 11 is used as a refrigerant radiator, the refrigerant flow is opposite to that described above.

(7) Features (7-1)
The outdoor heat exchanger 11 of the present embodiment has a communication part 64x in which the fins 64 are connected vertically on the windward side of the flat multi-hole tube 63, and more wind than the flat multi-hole tube 63 of the fins 64. 0.18 ≦ L / Wt for the upper part (L: distance in the air flow direction from the wind top of the flat multi-hole tube to the wind top of the fin, Wt: length of the flat multi-hole tube in the air flow direction) It is configured to satisfy. For this reason, for example, when the value of Wt is large (when the flat multi-hole pipe 63 is long), the ventilation resistance received when air passes through the outdoor heat exchanger 11 tends to increase, but Wt is increased. By increasing the area in which the temperature difference with the passing air is sufficiently secured and ensuring a sufficient dehumidification amount of the air passing on the windward side, the air flow direction center of the fins 64 to the leeward side Since the amount of frost attached can be suppressed, the increase in ventilation resistance can be moderated.

  In this way, when used as an evaporator, the communication portion 64x of the fin 64 that can be frosted is sufficiently wide at the windward side of the outdoor heat exchanger 11, so that the frost resistance is improved. Is possible. In particular, when L ≧ 4 mm, the effect of improving the frosting resistance can be obtained more reliably.

  Therefore, it is possible to eliminate the need to frequently perform the defrost operation performed to melt the frost attached to the outdoor heat exchanger 11. That is, it is possible to set the defrost determination condition loosely so that the defrost operation does not have to be performed frequently.

  In addition, since the communication part 64x of the fin 64 is configured to satisfy the relationship of L / Wt ≦ 0.32, by reducing unnecessary portions that are unlikely to contribute to the improvement of the frosting resistance, the fin 64 can be reduced. It is possible to reduce material costs.

(7-2)
In the outdoor heat exchanger 11, the temperature difference between the air passing through the outside of the flat multi-hole pipe 63 and the refrigerant passing through the passage 63b inside the flat multi-hole pipe 63 is conventionally higher in the air flow direction. Tends to be larger than the leeward side. For this reason, in the plurality of passages 63b provided side by side in the air flow direction in the flat multi-hole tube 63, the amount of heat exchange tends to be larger on the windward side of the airflow than on the leeward side.

  Furthermore, in the structure in which the communication part 64x of the fin 64 is provided on the windward side of the flat multi-hole tube 63 in order to improve the frosting resistance as described above, compared with a structure in which such a communication part 64x is not provided, More heat flux is supplied to the windward portion of the plurality of passages 63b of the flat multi-hole tube 63, and the heat exchange amount in the windward passage 63b of the airflow is on the leeward side. It tends to be larger than the passage 63b.

  Even in such a structure, the outdoor heat exchanger 11 of the present embodiment has a structure satisfying the relationship of 2 ≦ a / b (a: first and second from the windward side of the flat multi-hole pipe 63) The total value of the width of the passage 63b in the air flow direction, b: the width of the passage 63b located at the center of the length Wt of the flat multi-hole pipe 63 in the air flow direction), and the windward side of the passage 63b of the flat multi-hole pipe 63 By making the passage 63b larger, it is possible to correspond to the amount of heat flux supplied from the communicating portion 64x of the fin 64 on the windward side.

  As a result, among the passages 63b of the flat multi-hole pipe 63, a larger amount of refrigerant can be supplied in the windward passage 63b having a large heat flux supplied from the fin 64 than in the passage 63b on the leeward side. Therefore, the performance of the outdoor heat exchanger 11 is reduced by reducing the flow of the refrigerant without evaporating in the leeward passage 63b while suppressing the number of places where the evaporated refrigerant flows in the leeward passage 63b. It is possible to improve.

  In addition, when it is set as the structure which satisfy | fills the relationship of 3 <= a / b, it becomes possible to show | play the said effect more fully.

  Further, in the passage 63b located on the most windward side among the plurality of passages 63b of the flat multi-hole pipe 63, the heat flux supplied from the fins 64 becomes the largest, but the outdoor heat exchange of the present embodiment. In the vessel 11, the width a1 in the air flow direction of the windward passage 63b is secured 1.5 times or more the width b in the air flow direction of the passage 63b in the center of the flat multi-hole pipe 63 in the air flow direction. Therefore, the effect of improving the performance of the outdoor heat exchanger 11 can be sufficiently obtained.

(7-3)
The outdoor heat exchanger 11 of the present embodiment has a structure satisfying the relationship of a / b ≦ 16 while adopting the structure as described above.

  For this reason, it is possible to prevent the size of the relatively large passage 63b on the windward side of the flat multi-hole pipe 63 from becoming excessively large. As a result, the length in the air flow direction of the windward passage 63b of the flat multi-hole tube 63 can be prevented from becoming excessively larger than the length in the vertical direction of the passage 63b of the flat multi-hole tube 63. . Therefore, it is possible to easily secure the pressure resistance even in the relatively large passage 63b on the windward side of the flat multi-hole tube 63.

  In addition, when it is set as the structure satisfy | filling the relationship of a / b <= 9, it becomes possible to show | play the said effect more fully.

(7-4)
In the outdoor heat exchanger 11 of the present embodiment, the fin 64 has a leeward protrusion 64 y that protrudes further toward the leeward side than the leeward side end of the flat multi-hole tube 63, and the fin 64 has a leeward protrusion. The lower end of the wind at the portion 64y is located a distance Q (2 mm or more) away from the lower end of the flat multi-hole tube 63 further on the leeward side in the air flow direction.

  For this reason, even when the outdoor heat exchanger 11 functions as an evaporator and is used in a condition where condensation occurs, the condensed water that flows down from the wind lower end of each flat multi-hole pipe 63 flows into the fin 64. It is possible to make it difficult to supply to the wind bottom. Thereby, even if it is a case where frost adheres in the wind lower end of the fin 64, it can suppress that the said frost grows.

(8) Modification In the above embodiment, an example of the embodiment of the present invention has been described. However, the above embodiment is not intended to limit the present invention, and is not limited to the above embodiment. The present invention naturally includes aspects appropriately modified without departing from the spirit of the present invention.

(8-1) Modification A
In the said embodiment, the length (in the air flow direction of the notch part 64a of the fin 64 is provided by providing the leeward protrusion part 64y which protruded further toward the leeward side rather than the leeward side edge part of the flat multi-hole tube 63 ( The case where the length Wf of the fin 64 in the air flow direction—the distance L) is configured to be larger than the width Wt of the flat multi-hole tube 63 in the air flow direction has been described as an example.

  However, the relationship of the width in the air flow direction between the notch portion 64a of the fin 64 and the flat multi-hole tube 63 is not limited to this relationship. For example, as shown in FIG. However, the fin 64 may be configured to have the leeward exposed portion 63y that protrudes further toward the leeward side than the leeward side end portion of the fin 64. That is, the length of the notch 64a of the fin 64 in the air flow direction (the length Wf of the fin 64 in the air flow direction−the distance L) is smaller than the width Wt of the flat multi-hole tube 63 in the air flow direction. It may be configured.

  According to the said structure, since the lee end of the leeward exposed part 63y of the flat multi-hole pipe 63 is located further on the leeward side in the air flow direction than the lee end of the fin 64, the flat multi-hole is not the fin 64 but the flat multi-hole. A structure in which a part of the pipe 63 is exposed to the leeward side can be employed. Thereby, at the time of manufacture or transportation of the outdoor heat exchanger 11, damage or breakage of a portion on the leeward side of the fin 64 is less likely to occur, and the fin 64 can be protected.

  In addition, when the outdoor heat exchanger 11 is bent using a tool such as a roller, the leeward exposed portion 63y of the flat multi-hole tube 63 is projected to the leeward side instead of the fins 64. Can be pressed against the flat multi-hole tube 63 instead of the fin 64, and deformation and damage of the fin 64 can be suppressed. Furthermore, when brazing the outdoor heat exchanger 11 in the furnace, it is possible to braze the flat multi-hole pipe 63 in a grounded state instead of the fin 64, so that the aluminum fin 64 is brazed at the time of brazing. It is also possible to suppress deformation due to thermal contraction or thermal expansion of the fins 64 that may be caused by contact with the floor surface in the furnace.

  Further, the structure having the above-described leeward exposed portion 63y is preferably realized by a structure satisfying the relationship of 0.18 ≦ L / Wt ≦ 0.30 (L: top end of flat multi-hole tube) Distance in the air flow direction from the top end of the fin to the wind top, Wt: length of the flat multi-hole tube in the air flow direction). Thus, the unnecessary part which is hard to contribute to the improvement of frosting yield strength by configuring the portion on the windward side of the flat multi-hole pipe 63 of the fin 64 to satisfy the relationship of L / Wt ≦ 0.30. It is possible to sufficiently suppress the material cost of the fins by sufficiently reducing.

(8-2) Modification B
In the above embodiment, the case where only the passage 63b located on the most windward side among the passages 63b of the flat multi-hole pipe 63 is different from the other passages 63b in the air flow direction has been described as an example.

  However, the structure of the passage b of the flat multi-hole pipe 63 to correspond to many heat fluxes supplied from the fins 64 on the windward side is not limited to this, for example, as shown in FIG. The second passage 63b from the windward side in the flat multi-hole pipe 63 may be configured to have a larger width in the air flow direction than the windward side passage 63b. Even in this case, if the second passage 63b from the windward side, a large amount of heat flux supplied from the communication portion 64x of the fin 64 can be processed.

  Further, when the flat multi-hole pipe 63 is manufactured by extrusion molding, the windward end of the flat multi-hole pipe 63 in the air flow direction is the passage 63b that is positioned at the windward end of the plurality of paths 63b. The windward end of the plurality of passages 63b can have individual differences in the thickness of the wall surface of the section, or the windward end of the flat multi-hole tube 63 in the air flow direction is rounded. There is a possibility that the passage 63b that will be located at will be unintentionally small. However, even if there is such a fear, by designing the width in the air flow direction to be large in at least one of the windward path 63b and the second path 63b from the windward side, Even if the passage 63b located on the windward side is unintentionally small, it is possible to process a large amount of heat flux supplied from the communication portion 64x of the fin 64.

(8-3) Modification C
Moreover, as a structure of the channel | path b of the flat multi-hole tube 63 for making it respond | correspond to many heat fluxes supplied from the fin 64 in the windward side, as shown in FIG. 10, for example, the windward side in the flat multi-hole tube 63 The width of the passage 63b in the air flow direction may gradually decrease from the leeward side toward the leeward side. Even in this case, it is possible to process many heat fluxes supplied from the communication portion 64x of the fin 64.

  About the heat exchanger which has the structure which concerns on the said embodiment and the modification A, Wf: Length of the air flow direction of the fin 64, L: The distance of the air flow direction from the wind upper end of a flat multi-hole pipe to the wind upper end of a fin , Wt: length of the flat multi-hole tube in the air flow direction, a: total value of the width of the flat multi-hole tube 63 in the air flow direction of the first and second passages 63b from the windward side, b: flat multi-hole tube Table 1 shows the results of analysis when the values of the width of the passage 63b located at the center of the length Wt in the air flow direction 63 are changed as Examples 1 to 12.

  Examples 1, 2, 5, 6, 9, and 10 correspond to the structure in which the fin 64 in the above embodiment has the leeward protrusion 64y. In addition, Examples 3, 4, 7, 8, 11, and 12 correspond to the structure in which the flat multi-hole tube 63 in Modification A has the leeward exposed portion 63y.

  In any of the embodiments, the width of the passage 63b in the flat multi-hole pipe 63 in the air flow direction is different from that of the other passages only in the windward passage 63b.

  Q1, q2, and q3 shown in Table 1 are the heat flux at the surface of the windward end of the flat multi-hole tube 63, the heat flux at the center surface of the flat multi-hole tube 63, and the leeward of the flat multi-hole tube 63, respectively. The average value of the amount of heat flux at the surface of the side end is shown. In addition, these heat fluxes have shown the analysis value by the computer analysis based on computational fluid dynamics (CFD: computational fluid dynamics).

また、上記実施形態に係る構造を有する熱交換器について、Ｌの値を変化させた場合の着霜時間Ｔの違いを検討した解析結果を、実施例１３、１４、比較例１〜３として表２に示す。

Moreover, about the heat exchanger which has the structure which concerns on the said embodiment, the analysis result which examined the difference in the frost formation time T at the time of changing the value of L is shown as Examples 13 and 14 and Comparative Examples 1-3. It is shown in 2.

  In Examples 13 and 14 and Comparative Examples 1 to 3, the fin 64 in the above embodiment corresponds to the structure having the leeward protrusion 64y, Wt is fixed to 19 mm, Wf is L + Wt + 2 mm, and a = Only 1 mm, b = 0.5 mm, and only the windward passage 63b is shared as a different structure from the other passages.

  In addition, the frost formation time T is a time until the pressure loss received by the air flow supplied to the heat exchanger when the heat exchanger is used as an evaporator under common predetermined conditions increases by 200 Pa due to an increase in the amount of frost formation. Time required.

以上の実施例１３、１４に示すように、Ｌの値を大きくすることで着霜時間Ｔを増大させることができ、霜の付着による通風抵抗の増大を遅らせることが可能になることが確認された。なお、比較例２、３に示すように、Ｌの値がＷｔに対して大きすぎる場合には、フィンのＬに対応する部分のうちの着霜耐力の向上に寄与する部分を増大させることができず、単にフィンの材料費が増大するだけであることも確認された。

As shown in Examples 13 and 14 above, it was confirmed that the frosting time T can be increased by increasing the value of L, and the increase in ventilation resistance due to frost adhesion can be delayed. It was. In addition, as shown in Comparative Examples 2 and 3, when the value of L is too large with respect to Wt, it is possible to increase the portion of the portion corresponding to L of the fin that contributes to the improvement of frosting resistance. It was also confirmed that the material cost of the fins simply increased.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Outdoor unit 11 Outdoor heat exchanger (heat exchanger)
63 flat multi-hole pipe 63a flat surface 63b passage (refrigerant flow path)
63y leeward exposed part 64 fin 64a notch (notched part)
64x communication part (part connected up and down on the windward side)
64y leeward projecting portion a total value a1 width (width in the air flow direction of the refrigerant channel on the most windward side)
a2 width b width (width in the air flow direction of the refrigerant flow channel in the center of the flat multi-hole tube in the air flow direction)
L Distance in the air flow direction from the top of the flat multi-hole pipe to the top of the fin Wt Length of the flat multi-hole pipe in the air flow direction

    Patent Document 1: Japanese Patent Application Laid-Open No. 2002-139282

  The present invention relates to a heat exchanger.

  Conventionally, heat exchange is provided with a plurality of flat multi-hole tubes and fins joined to the plurality of flat multi-hole tubes, and exchanges heat between the refrigerant flowing inside the flat multi-hole tubes and the air flowing outside the flat multi-hole tubes. The vessel is known.

  For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-139282) proposes a heat exchanger in which a notch is formed in a fin from the leeward side toward the leeward side, and a flat multi-hole tube is inserted and fixed from the leeward side of the fin. Has been.

  In the heat exchanger shown in Patent Document 1, fins are not provided on the windward side of the windward end of the flat multi-hole tube. For this reason, when a heat exchanger is used as an evaporator having a low evaporation temperature in an environment where the outside air temperature is low, frost is concentrated on the fins of the heat exchanger and the windward portion of the flat multi-hole tube. Therefore, the increase in ventilation resistance tends to occur early. For this reason, it will be necessary to perform the operation | movement etc. for melting the frost adhering to a heat exchanger frequently.

  On the other hand, by providing fins further on the windward side than the windward end of the flat multi-hole tube, it is possible to alleviate the state where frost is concentrated on the windward side portion of the flat multi-hole tube. .

  However, when fins are provided further on the windward side than the windward end of the flat multi-hole tube in this way, the airflow direction is not correct due to the larger difference between the air temperature and the refrigerant temperature on the windward side. In addition to the balance, the amount of heat flux from the fins for the refrigerant channel on the windward side among the plurality of refrigerant channels provided in the flat multi-hole tube is larger than the amount of heat flux for the refrigerant channel on the leeward side. As a result, an imbalance in the air flow direction occurs. When this imbalance occurs, the refrigerant flowing in the refrigerant channel on the leeward side of the flat multi-hole tube will evaporate in the middle of the channel, but the refrigerant flowing in the refrigerant channel on the leeward side will be sufficiently evaporated. There is a possibility that the performance of the heat exchanger cannot be fully exhibited.

  The present invention has been made in view of the above points, and the object of the present invention is sufficient on both the leeward side and the leeward side in the air flow direction even when the increase in ventilation resistance due to frost adhesion is delayed. An object of the present invention is to provide a heat exchanger that can easily ensure the pressure-resistant strength of a flat multi-hole tube while exhibiting performance.

The heat exchanger according to the first aspect includes a flat multi-hole tube and a fin. The flat multi-hole tube has a plurality of refrigerant channels arranged in the air flow direction. A flat multi-hole tube is inserted and fixed at a location where the fin is cut out from the leeward side toward the leeward side in the air flow direction. The fin has a portion connected up and down on the windward side of the flat multi-hole tube. L: distance in the air flow direction from the wind upper end of the flat multi-hole tube to the wind upper end of the fin, Wt: length of the flat multi-hole tube in the air flow direction, a: first and second from the windward side of the flat multi-hole tube 0.18 ≦ L / Wt ≦ when the total value of the width of the refrigerant flow path in the air flow direction, b: the width of the refrigerant flow path in the center of the flat multi-hole tube in the air flow direction, 0.32 and the relationship of 2.5 ≦ a / b ≦ 16 is satisfied.

  As for “b”, when there is no refrigerant flow path in the center of the flat multi-hole tube (for example, there is a partition for partitioning each refrigerant flow path), the width of the nearest refrigerant flow path from the center. It may also be an average value of the widths of the two refrigerant channels sandwiching the center.

  It should be noted that the average length in the air flow direction of each refrigerant flow channel located on the windward side of each refrigerant flow channel located on the leeward side of each refrigerant flow channel located on the leeward side including the center of the flat multi-hole tube is It is preferable that it is larger.

  In this heat exchanger, the fin has a portion connected up and down on the windward side of the flat multi-hole tube, and 0.18 ≦ L / Wt for the portion on the windward side of the flat multi-hole tube of the fin. Therefore, a wide frostable area is ensured, and the frosting resistance can be improved. For this reason, it is possible to eliminate the need for frequent defrosting and operation performed to melt the frost attached to the heat exchanger. Moreover, since it is comprised so that the relationship of L / Wt <= 0.32 may be satisfy | filled about the part on the windward side from the flat multi-hole tube of a fin, the unnecessary part which is hard to contribute to the improvement of frost proof stress is reduced. This makes it possible to reduce the material cost of the fins.

  Here, the temperature difference between the air passing outside the flat multi-hole tube and the refrigerant passing through the refrigerant flow path of the flat multi-hole tube tends to be larger on the leeward side in the air flow direction than on the leeward side. . For this reason, in a plurality of refrigerant flow paths provided side by side in the air flow direction in the flat multi-hole tube, the amount of heat exchange tends to be larger on the windward side of the airflow than on the leeward side. In the structure in which the fins are positioned on the windward side of the flat multi-hole tube in order to improve the frosting resistance as described above, with respect to the windward side portion of the plurality of refrigerant channels of the flat multi-hole tube. Further, since the heat flux from the fin located on the leeward side is supplied, the amount of heat exchange in the refrigerant channel on the leeward side of the airflow tends to be larger than that on the leeward side refrigerant channel. .

  Even in such a structure, this heat exchanger has a structure satisfying the relationship of 2 ≦ a / b, so that the refrigerant channel on the leeward side of the refrigerant channel of the flat multi-hole tube is connected to the refrigerant flow on the windward side. The refrigerant channel on the windward side is made larger in the refrigerant channel of the flat multi-hole tube without making it larger than the path so as to correspond to the amount of heat flux supplied from the surrounding fins. Thereby, the performance of the heat exchanger can be improved. It is more preferable to satisfy the relationship of 2.5 ≦ a / b.

  In such a structure, the heat exchanger has a structure satisfying the relationship of a / b ≦ 16, so that the size of the relatively large refrigerant flow path on the windward side of the flat multi-hole tube in the air flow direction. Comparison of the upwind side of a flat multi-hole tube by ensuring that it does not become too large (by ensuring that the size in the air flow direction is not excessive relative to the length in the direction perpendicular to the air flow direction) It is easy to ensure pressure resistance even in a large refrigerant flow path.

  As described above, while adopting a structure that delays the increase in ventilation resistance due to the adhesion of frost, the performance of both the refrigerant channel on the windward side and the refrigerant channel on the leeward side in the air flow direction of the flat multi-hole tube is sufficient. It is possible to ensure the pressure resistance of the flat multi-hole tube while exhibiting it.

  The heat exchanger according to the second aspect is the heat exchanger according to the first aspect, and satisfies the relationship of 0.21 ≦ L / Wt ≦ 0.32. The leeward end of the fin is located further on the leeward side in the air flow direction than that of the flat multi-hole tube.

  In this heat exchanger, it is possible to more reliably improve the frosting resistance by securing a portion of the fin that is on the windward side of the flat multi-hole tube. Furthermore, since the lee end of the fin is located further on the leeward side in the air flow direction than the lee end of the flat multi-hole tube, the condensed water is lowered from the leeward lower end of the fin protruding to the leeward side. It is possible to improve the drainage efficiency of the condensed water.

  The heat exchanger which concerns on a 3rd viewpoint is a heat exchanger which concerns on a 2nd viewpoint, Comprising: The lee end of a fin is located in the leeward side further 2 mm or more away from the lee end of a flat multi-hole pipe.

  In general, in a structure in which condensed water is supplied to the wind lower end of the fin, when frost adheres to the wind lower end of the fin of the heat exchanger, the frost may grow.

  On the other hand, in this heat exchanger, the lee end of the fin is positioned further 2 mm or more away from the lee side of the flat multi-hole tube. For this reason, the dew condensation water that flows down from the wind lower end of the flat multi-hole tube is difficult to be supplied to the wind lower end of the fin, and it is possible to suppress the growth of frost at the wind lower end of the fin.

  The heat exchanger according to the fourth aspect is a heat exchanger according to the first aspect, and satisfies a relationship of 0.18 ≦ L / Wt ≦ 0.30. The lower end of the flat multi-hole tube is located further on the leeward side in the air flow direction than the lower end of the fin.

  Since this heat exchanger is configured to satisfy the relationship of L / Wt ≦ 0.30 for the portion on the windward side of the flat multi-hole tube of the fin, it is unnecessary to contribute to the improvement of the frosting resistance. By sufficiently reducing the portion, it is possible to sufficiently suppress the material cost of the fins.

  Further, in this heat exchanger, the flat multi-hole tube is positioned on the leeward side in the air flow direction further than the fin lower end, so that the flat multi-hole tube protrudes leeward rather than the fin. Thus, it is possible to protect the leeward side of the fin during manufacturing or transportation.

  In addition, by adopting a configuration in which a flat multi-hole tube is projected to the leeward side instead of a fin, for example, when bending a heat exchanger, a tool is pressed against the flat multi-hole tube to work. It is possible to suppress deformation and damage of the leeward fin. Further, when brazing in the furnace, the flat multi-hole tube, not the fins, can be grounded, and it is possible to suppress thermal contraction and deformation of the fins caused by the grounding of the fins.

  A heat exchanger according to a fifth aspect is a heat exchanger according to any one of the first to fourth aspects, and satisfies a relationship of 3 ≦ a / b ≦ 9.

  In this heat exchanger, by having a structure satisfying the relationship of 3 ≦ a / b, the refrigerant channel on the windward side of the refrigerant channel of the flat multi-hole tube is configured to be sufficiently large, so that the surrounding fins It is possible to improve the performance of the heat exchanger in accordance with the amount of heat flux supplied.

  Furthermore, in such a structure, in this heat exchanger, by satisfying the relationship of a / b ≦ 9, the size of the relatively large refrigerant flow path on the windward side of the flat multi-hole tube in the air flow direction Comparison of the upwind side of a flat multi-hole tube by ensuring that it does not become too large (by ensuring that the size in the air flow direction is not excessive relative to the length in the direction perpendicular to the air flow direction) It is easy to ensure sufficient pressure resistance even in a large refrigerant flow path.

  A heat exchanger according to a sixth aspect is the heat exchanger according to any one of the first to fifth aspects, and L ≧ 4 mm.

  In this heat exchanger, it is possible to improve the frosting resistance more reliably by securing sufficiently wide fins located on the windward side than the flat multi-hole tube.

  A heat exchanger according to a seventh aspect is the heat exchanger according to any one of the first to sixth aspects, wherein the width in the air flow direction of the refrigerant channel on the windward side of the flat multi-hole tube is flat. It is 1.5 times or more of the width in the air flow direction of the refrigerant flow path in the center of the air flow direction of the multi-hole tube, and preferably 2 times or more.

  In this heat exchanger, not only does the temperature difference between the refrigerant and the air tend to be larger on the windward side in the air flow direction, but the fins may spread on the windward side than the flat multi-hole tube, A large heat flux is supplied in the refrigerant flow path. Even with such a structure, it is possible to sufficiently exhibit the performance of the heat exchanger by sufficiently ensuring the size of the airflow direction of the most upstream refrigerant flow path.

  In the heat exchanger according to the first aspect, while adopting a structure that delays the increase in ventilation resistance due to adhesion of frost, an upwind refrigerant channel and a leeward refrigerant channel in the air flow direction of the flat multi-hole tube It is possible to ensure the pressure-resistant strength of the flat multi-hole tube while sufficiently exhibiting the performance of both.

  In the heat exchanger which concerns on a 2nd viewpoint, it becomes possible to improve the drainage efficiency of condensed water, improving frosting yield strength more reliably.

  In the heat exchanger according to the third aspect, the condensed water that flows down from the wind bottom end of the flat multi-hole tube is difficult to be supplied to the wind bottom end of the fin, and frost growth at the wind bottom end of the fin can be suppressed.

  In the heat exchanger which concerns on a 4th viewpoint, it becomes possible to protect the leeward side location of a fin at the time of manufacture or at the time of conveyance, fully suppressing the material cost of a fin.

  In the heat exchanger which concerns on a 5th viewpoint, it is easy to ensure sufficient pressure-resistant intensity | strength also in the comparatively big refrigerant | coolant flow path of the windward side of a flat multi-hole pipe | tube, improving the performance of a heat exchanger.

  In the heat exchanger according to the sixth aspect, it is possible to improve the frosting resistance more reliably by securing sufficiently wide fins located on the windward side than the flat multi-hole tube.

  In the heat exchanger which concerns on a 7th viewpoint, it becomes possible to fully exhibit the performance of a heat exchanger.

It is a schematic block diagram of the air conditioning apparatus by which the heat exchanger which concerns on one Embodiment of this invention was employ | adopted. It is an external appearance perspective view of an outdoor unit. It is a front view of an outdoor unit (shown excluding refrigerant circuit components other than the outdoor heat exchanger). It is a schematic perspective view of an outdoor heat exchanger. It is the elements on larger scale of the heat exchange part of FIG. It is the schematic which shows the attachment state with respect to the flat multi-hole pipe of a fin. It is a block diagram for demonstrating the refrigerant | coolant flow of an outdoor heat exchanger. It is the schematic which shows the attachment state with respect to the flat multi-hole pipe of the fin which concerns on the modification A. It is the schematic which shows the attachment state with respect to the flat multi-hole tube of the fin which concerns on the modification B. It is the schematic which shows the attachment state with respect to the flat multi-hole pipe of the fin which concerns on the modification C.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an air-conditioning apparatus in which an outdoor heat exchanger as a heat exchanger according to the present invention is employed and modifications thereof will be described with reference to the drawings. In addition, the specific structure of the outdoor heat exchanger as a heat exchanger which concerns on this invention is not restricted to the following embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

(1) Configuration of Air Conditioner FIG. 1 is a schematic configuration diagram of an air conditioner 1 that employs an outdoor heat exchanger 11 as a heat exchanger according to an embodiment of the present invention.

  The air conditioner 1 is a device capable of cooling and heating a room such as a building by performing a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2, indoor units 3a and 3b, a liquid refrigerant communication tube 4 and a gas refrigerant communication tube 5 that connect the outdoor unit 2 and the indoor units 3a and 3b, an outdoor unit 2 and And a control unit 23 that controls the constituent devices of the indoor units 3a and 3b. The vapor compression refrigerant circuit 6 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor units 3 a and 3 b via the refrigerant communication tubes 4 and 5.

  The outdoor unit 2 is installed outdoors (on the roof of a building, in the vicinity of the wall surface of the building, etc.) and constitutes a part of the refrigerant circuit 6. The outdoor unit 2 mainly includes an accumulator 7, a compressor 8, a four-way switching valve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12 as an expansion mechanism, a liquid side shut-off valve 13, and a gas side shut-off valve. 14 and an outdoor fan 15. Each device and the valve are connected by refrigerant pipes 16 to 22.

  The indoor units 3 a and 3 b are installed indoors (such as a living room or a ceiling space) and constitute a part of the refrigerant circuit 6. The indoor unit 3a mainly has an indoor expansion valve 31a, an indoor heat exchanger 32a, and an indoor fan 33a. The indoor unit 3b mainly includes an indoor expansion valve 31b as an expansion mechanism, an indoor heat exchanger 32b, and an indoor fan 33b.

  The refrigerant communication pipes 4 and 5 are refrigerant pipes that are constructed on site when the air conditioner 1 is installed at an installation location such as a building. One end of the liquid refrigerant communication tube 4 is connected to the liquid side closing valve 13 of the outdoor unit 2, and the other end of the liquid refrigerant communication tube 4 is connected to the liquid side ends of the indoor expansion valves 31a and 31b of the indoor units 3a and 3b. Has been. One end of the gas refrigerant communication pipe 5 is connected to the gas side shut-off valve 14 of the outdoor unit 2, and the other end of the gas refrigerant communication pipe 5 is connected to the gas side end of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b. It is connected.

  The control unit 23 is configured by communication connection of control boards and the like (not shown) provided in the outdoor unit 2 and the indoor units 3a and 3b. In FIG. 1, for the sake of convenience, the outdoor unit 2 and the indoor units 3a and 3b are illustrated at positions away from each other. The control unit 23 controls the components 8, 10, 12, 15, 31a, 31b, 33a, 33b of the air conditioner 1 (here, the outdoor unit 2 and the indoor units 3a, 3b), that is, the air conditioner 1 The whole operation control is performed.

(2) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 is demonstrated using FIG. In the air conditioner 1, in the cooling operation in which the refrigerant flows in the order of the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, the indoor expansion valves 31a and 31b, and the indoor heat exchangers 32a and 32b, the compressor 8, the indoor heat A heating operation is performed in which the refrigerant flows in the order of the exchangers 32a and 32b, the indoor expansion valves 31a and 31b, the outdoor expansion valve 12, and the outdoor heat exchanger 11. The cooling operation and the heating operation are performed by the control unit 23.

  During the cooling operation, the four-way switching valve 10 is switched to the outdoor heat dissipation state (the state shown by the solid line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the outdoor heat exchanger 11 through the four-way switching valve 10. The high-pressure gas refrigerant sent to the outdoor heat exchanger 11 dissipates heat by exchanging heat with outdoor air supplied as a cooling source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant radiator. Become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has radiated heat in the outdoor heat exchanger 11 is sent to the indoor expansion valves 31 a and 31 b through the outdoor expansion valve 12, the liquid-side closing valve 13, and the liquid refrigerant communication pipe 4. The refrigerant sent to the indoor expansion valves 31a and 31b is decompressed to the low pressure of the refrigeration cycle by the indoor expansion valves 31a and 31b, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the indoor expansion valves 31a and 31b is sent to the indoor heat exchangers 32a and 32b. The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with indoor air supplied as a heating source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Evaporate. As a result, the room air is cooled and then supplied to the room to cool the room. The low-pressure gas refrigerant evaporated in the indoor heat exchangers 32 a and 32 b is again sucked into the compressor 8 through the gas refrigerant communication pipe 5, the gas-side closing valve 14, the four-way switching valve 10, and the accumulator 7.

  During the heating operation, the four-way selector valve 10 is switched to the outdoor evaporation state (the state indicated by the broken line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8 and is compressed until it reaches the high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the indoor heat exchangers 32 a and 32 b through the four-way switching valve 10, the gas-side closing valve 14, and the gas refrigerant communication pipe 5. The high-pressure gas refrigerant sent to the indoor heat exchangers 32a and 32b dissipates heat by exchanging heat with indoor air supplied as a cooling source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Becomes a high-pressure liquid refrigerant. Thereby, indoor air is heated, and indoor heating is performed by being supplied indoors after that. The high-pressure liquid refrigerant radiated by the indoor heat exchangers 32 a and 32 b is sent to the outdoor expansion valve 12 through the indoor expansion valves 31 a and 31 b, the liquid refrigerant communication tube 4 and the liquid-side closing valve 13. The refrigerant sent to the outdoor expansion valve 12 is decompressed to the low pressure of the refrigeration cycle by the outdoor expansion valve 12, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the outdoor expansion valve 12 is sent to the outdoor heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant sent to the outdoor heat exchanger 11 exchanges heat with outdoor air supplied as a heating source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant evaporator. Go and evaporate into a low-pressure gas refrigerant. The low-pressure refrigerant evaporated in the outdoor heat exchanger 11 is again sucked into the compressor 8 through the four-way switching valve 10 and the accumulator 7.

  In the state where the outdoor heat exchanger 11 functions as the refrigerant evaporator during the heating operation, if the outdoor air temperature or the refrigerant evaporation temperature satisfies a predetermined operating condition, the outdoor heat exchanger 11 is frosted. May adhere. If a lot of the frost adheres, the air supplied from the outdoor fan 15 receives excessive ventilation resistance when passing through the outdoor heat exchanger 11 to which the frost has adhered, and the heat exchange efficiency decreases. There is a risk that. Therefore, when a predetermined defrost determination condition such as a state where the predetermined operating condition is satisfied for a predetermined time or longer is satisfied, the control unit 23 causes the four-way switching valve 10 to move to the outdoor heat dissipation state (indicated by the solid line in FIG. 1). Switch to the state shown) and perform defrost operation. When the defrost process is completed, for example, when the defrost operation is performed for a predetermined time, the control unit 23 switches the four-way switching valve 10 to the outdoor evaporation state (the state indicated by the broken line in FIG. 1) again to perform the heating operation. To resume.

(3) Configuration of Outdoor Unit FIG. 2 is an external perspective view of the outdoor unit 2. FIG. 3 is a front view of the outdoor unit 2 (illustrated excluding refrigerant circuit components other than the outdoor heat exchanger 11). FIG. 4 is a schematic perspective view of the outdoor heat exchanger 11. FIG. 5 is a partially enlarged view of the heat exchange unit 60 of FIG. FIG. 6 is a schematic view showing a state in which the fin 64 is attached to the flat multi-hole tube 63. FIG. 7 is a configuration diagram for explaining a refrigerant flow in the outdoor heat exchanger 11.

(3-1) Overall Configuration The outdoor unit 2 is a top-blow-type heat exchange unit that sucks air from the side surface of the casing 40 and blows air from the top surface of the casing 40. The outdoor unit 2 mainly includes a substantially rectangular parallelepiped box-shaped casing 40, an outdoor fan 15 as a blower, devices 7, 8, 11 such as a compressor and an outdoor heat exchanger, a four-way switching valve, an outdoor expansion valve, and the like. And refrigerant circuit components that constitute a part of the refrigerant circuit 6 including the valves 10, 12 to 14, the refrigerant pipes 16 to 22, and the like. In the following description, “top”, “bottom”, “left”, “right”, “front”, “back”, “front”, and “back” are shown in FIG. 2 unless otherwise specified. The direction when the outdoor unit 2 to be viewed is viewed from the front (left oblique front side of the drawing) is meant.

  The casing 40 mainly includes a bottom frame 42 that spans a pair of installation legs 41 that extend in the left-right direction, a column 43 that extends vertically from a corner of the bottom frame 42, and a fan module 44 that is attached to the upper end of the column 43. And a front panel 45. Air inlets 40a, 40b, 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and an air outlet 40d is formed on the top surface.

  The bottom frame 42 forms the bottom surface of the casing 40, and the outdoor heat exchanger 11 is provided on the bottom frame 42. Here, the outdoor heat exchanger 11 is a substantially U-shaped heat exchanger in plan view facing the back surface and both left and right side surfaces of the casing 40, and substantially forms the back surface and both left and right side surfaces of the casing 40. .

  A fan module 44 is provided on the upper side of the outdoor heat exchanger 11, and forms a portion above the front and rear surfaces of the casing 40, the left and right support columns 43, and the top surface of the casing 40. . Here, the fan module 44 is an assembly in which the outdoor fan 15 is accommodated in a substantially rectangular parallelepiped box having an upper surface and a lower surface opened. The opening on the top surface of the fan module 44 is an air outlet 40d, and an air outlet grill 46 is provided at the air outlet 40d. The outdoor fan 15 is disposed in the casing 40 so as to face the air outlet 40d, and is a blower that takes air into the casing 40 from the suction ports 40a, 40b, and 40c and discharges it from the air outlet 40d.

  The front panel 45 is spanned between the support columns 43 on the front side, and forms the front surface of the casing 40.

  In the casing 40, refrigerant circuit components other than the outdoor fan 15 and the outdoor heat exchanger 11 (accumulator 7, compressor 8, and refrigerant pipes 16 to 18 are shown in FIG. 2) are also housed. Here, the compressor 8 and the accumulator 7 are provided on the bottom frame 42.

  Thus, the outdoor unit 2 includes a casing 40 in which air inlets 40a, 40b, and 40c are formed on the side surfaces (here, the rear surface and the left and right side surfaces), and an air outlet 40d is formed on the top surface. It has the outdoor fan 15 arrange | positioned facing the blower outlet 40d in the inside, and the outdoor heat exchanger 11 arrange | positioned in the casing 40 under the outdoor fan 15 inside. In such a top-blow type unit configuration, the outdoor heat exchanger 11 is disposed below the outdoor fan 15, and therefore the wind speed of the air passing through the outdoor heat exchanger 11 is different from that of the outdoor heat exchanger 11. The upper part tends to be faster than the lower part of the outdoor heat exchanger 11.

(3-2) Outdoor heat exchanger The outdoor heat exchanger 11 is a heat exchanger that performs heat exchange between the refrigerant and the outdoor air, and mainly includes a first header collecting pipe 80, a second header collecting pipe 90, A plurality of flat multi-hole tubes 63 and a plurality of fins 64 are provided. Here, all of the first header collecting pipe 80, the second header collecting pipe 90, the flat multi-hole pipe 63 and the fin 64 are formed of aluminum or an aluminum alloy, and are joined to each other by brazing or the like.

  Each of the first header collecting pipe 80 and the second header collecting pipe 90 is a vertically long hollow cylindrical member. The first header collecting pipe 80 is erected on one end side of the outdoor heat exchanger 11 (here, the left front end side in FIG. 4), and the second header collecting pipe 90 is the other end of the outdoor heat exchanger 11. It is erected on the side (here, the right front end side in FIG. 4).

(4) Flat multi-hole tube The flat multi-hole tube 63 is a flat multi-hole tube having a flat surface 63a on an upper surface and a lower surface facing the vertical direction as a heat transfer surface, and a large number of small passages 63b through which a refrigerant flows. The plurality of passages 63b included in the flat multi-hole tube 63 are provided side by side along the air flow direction (longitudinal direction in a cross-sectional view of the passage 63b). In the present embodiment, the flat multi-hole pipe 63 has a uniform vertical width, and the passage 63b has a uniform vertical width. The plurality of passages 63b are different in size, and are configured such that the flow passage area is larger as the passage is located on the windward side. More specifically, the flat multi-hole pipe 63 of the present embodiment is configured such that the width in the air flow direction of the passage 63b located on the furthest side is the width a1, The passage 63b is configured such that the width in the air flow direction is the width a2, and the relation of width a1> width a2 is satisfied (in this embodiment, the length Wt of the flat multi-hole pipe 63 in the air flow direction). The width b of the passage 63b located at the center of the center is the same as the width a2.) When the total value a = a1 + a2 of the width in the air flow direction of the first and second passages 63b from the windward side in the flat multi-hole tube 63 is set to satisfy the relationship 2 ≦ a / b ≦ 16. Has been. The relationship is more preferably a relationship satisfying 3 ≦ a / b ≦ 9.

  The width a1 in the air flow direction of the windward passage 63b of the flat multi-hole tube 63 is 1.5 times or more the width b in the air flow direction of the center passage 63b of the flat multi-hole tube 63. It is preferable that the number is twice or more.

  In addition, although it does not specifically limit about the part which divides between each channel | path 63b of the flat multi-hole pipe 63, Each may have the same width | variety in an air flow direction.

  The flat multi-hole tube 63 is not particularly limited, but is manufactured by, for example, extrusion molding.

  A plurality of flat multi-hole tubes 63 are arranged in the vertical direction at a predetermined interval (between centers in the height direction: a predetermined pitch Tp). Although not particularly limited, for example, the relationship between the vertical thickness Tt of the flat multi-hole tube 63 and the predetermined pitch Tp satisfies the relationship of Tp = 5 Tt to 9 Tt (more preferably Tp = 6 Tt to 8 Tt). It is preferable that the flat multi-hole pipes 63 are densely arranged in the vertical direction. Here, when the predetermined pitch Tp is too short, there is a problem of an increase in ventilation resistance due to a narrow space between the flat multi-hole pipes 63 and an increase in cost due to an increase in the number of flat multi-hole pipes 63. Arise. Further, if the predetermined pitch Tp is too long, a portion of the fin 64 that is far away from the flat multi-hole tube 63 becomes large, so that there is a problem that the heat transfer efficiency in the fin 64 decreases. Further, when the thickness Tt of the flat multi-hole tube 63 is too large, the refrigerant passage area of the passage 63b becomes too large, and the flow rate of the refrigerant in the passage 63b decreases, so that the heat transfer coefficient in the tube In which the flow resistance of the flat multi-hole pipe 63 in the flow direction crossing the flat multi-hole pipe 63 (dead water area) ) Increases, the heat transfer efficiency of the fins 64 decreases, and the cost increases due to an increase in the wall thickness to ensure the pressure resistance accompanying the increase in the size of the flat multi-hole tube 63 In addition, there is a problem that the amount of refrigerant increases due to an increase in the refrigerant passage area in the passage 63b. Further, when the thickness Tt of the flat multi-hole tube 63 is too small, there is a problem that the pressure loss received by the refrigerant increases due to the refrigerant passage area of the passage 63b being reduced. Considering the above matters, the relationship between the thickness Tt of the flat multi-hole tube 63 and the predetermined pitch Tp preferably satisfies the above-described relationship.

  In the flat multi-hole pipe 63, both ends of each passage 63b are connected to the first header collecting pipe 80 and the second header collecting pipe 90.

(5) Fins The fins 64 are plate-like members extending in the air flow direction and the vertical direction, and a plurality of fins 64 are arranged at predetermined intervals in the plate thickness direction, and are fixed to the flat multi-hole tube 63. The fin 64 is formed with a plurality of cutout portions 64a that are cut in the horizontal direction from the edge on the leeward side toward the windward side and before the edge on the windward side. The shape of the cutout portion 64a substantially matches the outer shape of the cross section of the flat multi-hole tube 63, and is brazed and fixed to the cutout portion 64a in a state where the flat multi-hole tube 63 is inserted.

  The fin 64 has a communication portion 64x that is continuous in the vertical direction on the windward side of the flat multi-hole tube 63 on the windward side. Here, the distance L in the air flow direction from the wind upper end of the flat multi-hole tube 63 to the wind upper end of the communication portion 64x of the fin 64 and the length Wt of the flat multi-hole tube 63 in the air flow direction are 0.18. ≦ L / Wt ≦ 0.32 is satisfied. The relationship is more preferably a relationship satisfying 0.21 ≦ L / Wt ≦ 0.32. Further, the distance L satisfies the relationship of L ≧ 4 mm from the viewpoint of ensuring a sufficiently wide portion located on the windward side of the flat multi-hole tube 63 of the fin 64 and improving the frosting resistance more reliably. More preferred.

  The fin 64 has a leeward projecting portion 64 y that projects further toward the leeward side than the leeward side end portion of the flat multi-hole tube 63. That is, the length of the notch 64a of the fin 64 in the air flow direction (the length Wf of the fin 64 in the air flow direction−the distance L) is larger than the width Wt of the flat multi-hole tube 63 in the air flow direction. It is configured. Here, the distance Q in the air flow direction from the wind lower end of the flat multi-hole tube 63 to the wind lower end of the leeward protrusion 64y of the fin 64 is configured to be 2 mm or more. The upper limit of the distance Q is not particularly limited, but can be 5 mm, for example, in order to reduce the material cost of the fins 64.

(6) Other Configurations of Outdoor Heat Exchanger The outdoor heat exchanger 11 has a heat exchanging unit 60 configured by fixing fins 64 to flat multi-hole pipes 63 arranged in the vertical direction. The heat exchange unit 60 includes an upper stage upper heat exchange unit 60A and a lower stage lower heat exchange unit 60B.

  The first header collecting pipe 80 is vertically partitioned by a partition plate 81 whose horizontal space extends in the horizontal direction, so that the gas side inlet / outlet communication space corresponds to the upper heat exchange section 60A and the lower heat exchange section 60B. 80A and a liquid side inlet / outlet communication space 80B are formed. And the flat multi-hole pipe 63 which comprises the corresponding upper stage heat exchange part 60A is connecting to 80 A of gas side inlet-and-outlet communication spaces. In addition, a flat multi-hole pipe 63 constituting a corresponding lower heat exchange section 60B communicates with the liquid side inlet / outlet communication space 80B.

  In addition, a refrigerant pipe 19 (see FIG. 1) for sending the refrigerant sent from the compressor 8 during the cooling operation to the gas side inlet / outlet communication space 80A is connected to the gas side inlet / outlet communication space 80A of the first header collecting pipe 80. .

  In addition, a refrigerant pipe 20 (see FIG. 1) for sending the refrigerant sent from the outdoor expansion valve 12 during the heating operation to the liquid side inlet / outlet communication space 80B is connected to the liquid side inlet / outlet communication space 80B of the first header collecting pipe 80. Yes.

  The second header collecting pipe 90 is divided into partitions with nozzles provided between the partition plate 92 and the partition plate 93 while being partitioned vertically by partition plates 91, 92, 93, 94 whose internal space is expanded in the horizontal direction. By being divided vertically by the plate 99, first to third upper folded communication spaces 90A, 90B, 90C and first to third lower folded communication spaces 90D, 90E, 90F arranged in order from the upper side are formed. ing. The flat multi-hole pipe 63 in the corresponding upper heat exchange section 60A communicates with the first to third upper folded communication spaces 90A, 90B, 90C, and the first to third lower folded communication spaces 90D, 90E, 90F. Is connected to the flat multi-hole pipe 63 in the corresponding lower heat exchange section 60B. The third upper-stage folded communication space 90C and the first lower-stage folded communication space 90D are partitioned vertically by a partition plate 99 with nozzles, but a nozzle 99a provided so as to penetrate vertically in the partition plate 99 with nozzles is provided. Via the top and bottom. In addition, the first upper-stage folded communication space 90A and the third lower-stage folded communication space 90F are connected via the first connection pipe 24 connected to the second header collecting pipe 90, and the second upper-stage folded communication space 90F. 90B and the second lower folded communication space 90E are connected via a second connection pipe 25 connected to the second header collecting pipe 90.

  With the above configuration, when the outdoor heat exchanger 11 functions as a refrigerant evaporator, the refrigerant that has flowed from the refrigerant pipe 20 into the liquid side inlet / outlet communication space 80B of the first header collecting pipe 80 flows into the liquid side inlet / outlet communication space. It flows through the flat multi-hole tube 63 of the lower heat exchange section 60B connected to 80B and flows into the first to third lower folded communication spaces 90D, 90E, 90F of the second header collecting tube 90. The refrigerant that has flowed into the first lower folded communication space 90D flows into the third upper folded communication space 90C via the nozzle 99a of the partition plate 99 with nozzle, and is connected to the third upper folded communication space 90C. It flows into the gas side inlet / outlet communication space 80A of the first header collecting pipe 80 via the flat multi-hole pipe 63 of the portion 60A. The refrigerant that has flowed into the second lower folded communication space 90E flows into the second upper folded communication space 90B through the second connection pipe 25, and is connected to the second upper folded communication space 90B. The gas flows into the gas side inlet / outlet communication space 80 </ b> A of the first header collecting pipe 80 through the flat multi-hole pipe 63. The refrigerant that has flowed into the third lower folded communication space 90F flows into the first upper folded communication space 90A via the first connection pipe 24, and is connected to the first upper folded communication space 90A. The gas flows into the gas side inlet / outlet communication space 80 </ b> A of the first header collecting pipe 80 through the flat multi-hole pipe 63. The refrigerant merged in the gas side inlet / outlet communication space 80 </ b> A of the first header collecting pipe 80 flows to the outside of the outdoor heat exchanger 11 through the refrigerant pipe 19. When the outdoor heat exchanger 11 is used as a refrigerant radiator, the refrigerant flow is opposite to that described above.

(7) Features (7-1)
The outdoor heat exchanger 11 of the present embodiment has a communication part 64x in which the fins 64 are connected vertically on the windward side of the flat multi-hole tube 63, and more wind than the flat multi-hole tube 63 of the fins 64. 0.18 ≦ L / Wt for the upper part (L: distance in the air flow direction from the wind top of the flat multi-hole tube to the wind top of the fin, Wt: length of the flat multi-hole tube in the air flow direction) It is configured to satisfy. For this reason, for example, when the value of Wt is large (when the flat multi-hole pipe 63 is long), the ventilation resistance received when air passes through the outdoor heat exchanger 11 tends to increase, but Wt is increased. By increasing the area in which the temperature difference with the passing air is sufficiently secured and ensuring a sufficient dehumidification amount of the air passing on the windward side, the air flow direction center of the fins 64 to the leeward side Since the amount of frost attached can be suppressed, the increase in ventilation resistance can be moderated.

  In this way, when used as an evaporator, the communication portion 64x of the fin 64 that can be frosted is sufficiently wide at the windward side of the outdoor heat exchanger 11, so that the frost resistance is improved. Is possible. In particular, when L ≧ 4 mm, the effect of improving the frosting resistance can be obtained more reliably.

  Therefore, it is possible to eliminate the need to frequently perform the defrost operation performed to melt the frost attached to the outdoor heat exchanger 11. That is, it is possible to set the defrost determination condition loosely so that the defrost operation does not have to be performed frequently.

  In addition, since the communication part 64x of the fin 64 is configured to satisfy the relationship of L / Wt ≦ 0.32, by reducing unnecessary portions that are unlikely to contribute to the improvement of the frosting resistance, the fin 64 can be reduced. It is possible to reduce material costs.

(7-2)
In the outdoor heat exchanger 11, the temperature difference between the air passing through the outside of the flat multi-hole pipe 63 and the refrigerant passing through the passage 63b inside the flat multi-hole pipe 63 is conventionally higher in the air flow direction. Tends to be larger than the leeward side. For this reason, in the plurality of passages 63b provided side by side in the air flow direction in the flat multi-hole tube 63, the amount of heat exchange tends to be larger on the windward side of the airflow than on the leeward side.

  Furthermore, in the structure in which the communication part 64x of the fin 64 is provided on the windward side of the flat multi-hole tube 63 in order to improve the frosting resistance as described above, compared with a structure in which such a communication part 64x is not provided, More heat flux is supplied to the windward portion of the plurality of passages 63b of the flat multi-hole tube 63, and the heat exchange amount in the windward passage 63b of the airflow is on the leeward side. It tends to be larger than the passage 63b.

  Even in such a structure, the outdoor heat exchanger 11 of the present embodiment has a structure satisfying the relationship of 2 ≦ a / b (a: first and second from the windward side of the flat multi-hole pipe 63) The total value of the width of the passage 63b in the air flow direction, b: the width of the passage 63b located at the center of the length Wt of the flat multi-hole pipe 63 in the air flow direction), and the windward side of the passage 63b of the flat multi-hole pipe 63 By making the passage 63b larger, it is possible to correspond to the amount of heat flux supplied from the communicating portion 64x of the fin 64 on the windward side.

  As a result, among the passages 63b of the flat multi-hole pipe 63, a larger amount of refrigerant can be supplied in the windward passage 63b having a large heat flux supplied from the fin 64 than in the passage 63b on the leeward side. Therefore, the performance of the outdoor heat exchanger 11 is reduced by reducing the flow of the refrigerant without evaporating in the leeward passage 63b while suppressing the number of places where the evaporated refrigerant flows in the leeward passage 63b. It is possible to improve.

  In addition, when it is set as the structure which satisfy | fills the relationship of 3 <= a / b, it becomes possible to show | play the said effect more fully.

  Further, in the passage 63b located on the most windward side among the plurality of passages 63b of the flat multi-hole pipe 63, the heat flux supplied from the fins 64 becomes the largest, but the outdoor heat exchange of the present embodiment. In the vessel 11, the width a1 in the air flow direction of the windward passage 63b is secured 1.5 times or more the width b in the air flow direction of the passage 63b in the center of the flat multi-hole pipe 63 in the air flow direction. Therefore, the effect of improving the performance of the outdoor heat exchanger 11 can be sufficiently obtained.

(7-3)
The outdoor heat exchanger 11 of the present embodiment has a structure satisfying the relationship of a / b ≦ 16 while adopting the structure as described above.

  For this reason, it is possible to prevent the size of the relatively large passage 63b on the windward side of the flat multi-hole pipe 63 from becoming excessively large. As a result, the length in the air flow direction of the windward passage 63b of the flat multi-hole tube 63 can be prevented from becoming excessively larger than the length in the vertical direction of the passage 63b of the flat multi-hole tube 63. . Therefore, it is possible to easily secure the pressure resistance even in the relatively large passage 63b on the windward side of the flat multi-hole tube 63.

  In addition, when it is set as the structure satisfy | filling the relationship of a / b <= 9, it becomes possible to show | play the said effect more fully.

(7-4)
In the outdoor heat exchanger 11 of the present embodiment, the fin 64 has a leeward protrusion 64 y that protrudes further toward the leeward side than the leeward side end of the flat multi-hole tube 63, and the fin 64 has a leeward protrusion. The lower end of the wind at the portion 64y is located a distance Q (2 mm or more) away from the lower end of the flat multi-hole tube 63 further on the leeward side in the air flow direction.

  For this reason, even when the outdoor heat exchanger 11 functions as an evaporator and is used in a condition where condensation occurs, the condensed water that flows down from the wind lower end of each flat multi-hole pipe 63 flows into the fin 64. It is possible to make it difficult to supply to the wind bottom. Thereby, even if it is a case where frost adheres in the wind lower end of the fin 64, it can suppress that the said frost grows.

(8) Modification In the above embodiment, an example of the embodiment of the present invention has been described. However, the above embodiment is not intended to limit the present invention, and is not limited to the above embodiment. The present invention naturally includes aspects appropriately modified without departing from the spirit of the present invention.

(8-1) Modification A
In the said embodiment, the length (in the air flow direction of the notch part 64a of the fin 64 is provided by providing the leeward protrusion part 64y which protruded further toward the leeward side rather than the leeward side edge part of the flat multi-hole tube 63 ( The case where the length Wf of the fin 64 in the air flow direction—the distance L) is configured to be larger than the width Wt of the flat multi-hole tube 63 in the air flow direction has been described as an example.

  However, the relationship of the width in the air flow direction between the notch portion 64a of the fin 64 and the flat multi-hole tube 63 is not limited to this relationship. For example, as shown in FIG. However, the fin 64 may be configured to have the leeward exposed portion 63y that protrudes further toward the leeward side than the leeward side end portion of the fin 64. That is, the length of the notch 64a of the fin 64 in the air flow direction (the length Wf of the fin 64 in the air flow direction−the distance L) is smaller than the width Wt of the flat multi-hole tube 63 in the air flow direction. It may be configured.

  According to the said structure, since the lee end of the leeward exposed part 63y of the flat multi-hole pipe 63 is located further on the leeward side in the air flow direction than the lee end of the fin 64, the flat multi-hole is not the fin 64 but the flat multi-hole. A structure in which a part of the pipe 63 is exposed to the leeward side can be employed. Thereby, at the time of manufacture or transportation of the outdoor heat exchanger 11, damage or breakage of a portion on the leeward side of the fin 64 is less likely to occur, and the fin 64 can be protected.

  In addition, when the outdoor heat exchanger 11 is bent using a tool such as a roller, the leeward exposed portion 63y of the flat multi-hole tube 63 is projected to the leeward side instead of the fins 64. Can be pressed against the flat multi-hole tube 63 instead of the fin 64, and deformation and damage of the fin 64 can be suppressed. Furthermore, when brazing the outdoor heat exchanger 11 in the furnace, it is possible to braze the flat multi-hole pipe 63 in a grounded state instead of the fin 64, so that the aluminum fin 64 is brazed at the time of brazing. It is also possible to suppress deformation due to thermal contraction or thermal expansion of the fins 64 that may be caused by contact with the floor surface in the furnace.

  Further, the structure having the above-described leeward exposed portion 63y is preferably realized by a structure satisfying the relationship of 0.18 ≦ L / Wt ≦ 0.30 (L: top end of flat multi-hole tube) Distance in the air flow direction from the top end of the fin to the wind top, Wt: length of the flat multi-hole tube in the air flow direction). Thus, the unnecessary part which is hard to contribute to the improvement of frosting yield strength by configuring the portion on the windward side of the flat multi-hole pipe 63 of the fin 64 to satisfy the relationship of L / Wt ≦ 0.30. It is possible to sufficiently suppress the material cost of the fins by sufficiently reducing.

(8-2) Modification B
In the above embodiment, the case where only the passage 63b located on the most windward side among the passages 63b of the flat multi-hole pipe 63 is different from the other passages 63b in the air flow direction has been described as an example.

  However, the structure of the passage b of the flat multi-hole pipe 63 to correspond to many heat fluxes supplied from the fins 64 on the windward side is not limited to this, for example, as shown in FIG. The second passage 63b from the windward side in the flat multi-hole pipe 63 may be configured to have a larger width in the air flow direction than the windward side passage 63b. Even in this case, if the second passage 63b from the windward side, a large amount of heat flux supplied from the communication portion 64x of the fin 64 can be processed.

  Further, when the flat multi-hole pipe 63 is manufactured by extrusion molding, the windward end of the flat multi-hole pipe 63 in the air flow direction is the passage 63b that is positioned at the windward end of the plurality of paths 63b. The windward end of the plurality of passages 63b can have individual differences in the thickness of the wall surface of the section, or the windward end of the flat multi-hole tube 63 in the air flow direction is rounded. There is a possibility that the passage 63b that will be located at will be unintentionally small. However, even if there is such a fear, by designing the width in the air flow direction to be large in at least one of the windward path 63b and the second path 63b from the windward side, Even if the passage 63b located on the windward side is unintentionally small, it is possible to process a large amount of heat flux supplied from the communication portion 64x of the fin 64.

(8-3) Modification C
Moreover, as a structure of the channel | path b of the flat multi-hole tube 63 for making it respond | correspond to many heat fluxes supplied from the fin 64 in the windward side, as shown in FIG. 10, for example, the windward side in the flat multi-hole tube 63 The width of the passage 63b in the air flow direction may gradually decrease from the leeward side toward the leeward side. Even in this case, it is possible to process many heat fluxes supplied from the communication portion 64x of the fin 64.

  About the heat exchanger which has the structure which concerns on the said embodiment and the modification A, Wf: Length of the air flow direction of the fin 64, L: The distance of the air flow direction from the wind upper end of a flat multi-hole pipe to the wind upper end of a fin , Wt: length of the flat multi-hole tube in the air flow direction, a: total value of the width of the flat multi-hole tube 63 in the air flow direction of the first and second passages 63b from the windward side, b: flat multi-hole tube Table 1 shows the results of analysis when the values of the width of the passage 63b located at the center of the length Wt in the air flow direction 63 are changed as Examples 1 to 12.

  Examples 1, 2, 5, 6, 9, and 10 correspond to the structure in which the fin 64 in the above embodiment has the leeward protrusion 64y. In addition, Examples 3, 4, 7, 8, 11, and 12 correspond to the structure in which the flat multi-hole tube 63 in Modification A has the leeward exposed portion 63y.

  In any of the embodiments, the width of the passage 63b in the flat multi-hole pipe 63 in the air flow direction is different from that of the other passages only in the windward passage 63b.

  Q1, q2, and q3 shown in Table 1 are the heat flux at the surface of the windward end of the flat multi-hole tube 63, the heat flux at the center surface of the flat multi-hole tube 63, and the leeward of the flat multi-hole tube 63, respectively. The average value of the amount of heat flux at the surface of the side end is shown. In addition, these heat fluxes have shown the analysis value by the computer analysis based on computational fluid dynamics (CFD: computational fluid dynamics).

  Moreover, about the heat exchanger which has the structure which concerns on the said embodiment, the analysis result which examined the difference in the frost formation time T at the time of changing the value of L is shown as Examples 13 and 14 and Comparative Examples 1-3. It is shown in 2.

  In Examples 13 and 14 and Comparative Examples 1 to 3, the fin 64 in the above embodiment corresponds to the structure having the leeward protrusion 64y, Wt is fixed to 19 mm, Wf is L + Wt + 2 mm, and a = Only 1 mm, b = 0.5 mm, and only the windward passage 63b is shared as a different structure from the other passages.

  In addition, the frost formation time T is a time until the pressure loss received by the air flow supplied to the heat exchanger when the heat exchanger is used as an evaporator under common predetermined conditions increases by 200 Pa due to an increase in the amount of frost formation. Time required.

  As shown in Examples 13 and 14 above, it was confirmed that the frosting time T can be increased by increasing the value of L, and the increase in ventilation resistance due to frost adhesion can be delayed. It was. In addition, as shown in Comparative Examples 2 and 3, when the value of L is too large with respect to Wt, it is possible to increase the portion of the portion corresponding to L of the fin that contributes to the improvement of frosting resistance. It was also confirmed that the material cost of the fins simply increased.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Outdoor unit 11 Outdoor heat exchanger (heat exchanger)
63 flat multi-hole pipe 63a flat surface 63b passage (refrigerant flow path)
63y leeward exposed part 64 fin 64a notch (notched part)
64x communication part (part connected up and down on the windward side)
64y leeward projecting portion a total value a1 width (width in the air flow direction of the refrigerant channel on the most windward side)
a2 width b width (width in the air flow direction of the refrigerant flow channel in the center of the flat multi-hole tube in the air flow direction)
L Distance in the air flow direction from the top of the flat multi-hole pipe to the top of the fin Wt Length of the flat multi-hole pipe in the air flow direction

    Patent Document 1: Japanese Patent Application Laid-Open No. 2002-139282

Claims (7)

A flat multi-hole pipe (63) having a plurality of refrigerant flow paths (63b) arranged in the air flow direction;
The flat multi-hole tube is inserted and fixed at a portion (64a) cut out from the leeward side toward the windward side in the air flow direction, and a portion (64x) connected vertically at the windward side of the flat multi-hole tube A fin (64) having
With
L: distance in the air flow direction from the wind top of the flat multi-hole tube to the wind top of the fin,
Wt: length of the flat multi-hole tube in the air flow direction,
a: the total value of the width in the air flow direction of the first and second refrigerant flow paths from the windward side in the flat multi-hole tube,
b: the width in the air flow direction of the refrigerant flow path at the center in the air flow direction in the flat multi-hole tube,
When 0.18 ≦ L / Wt ≦ 0.32
And
2 ≦ a / b ≦ 16
Satisfy the relationship
Heat exchanger (11). Satisfies the relationship of 0.21 ≦ L / Wt ≦ 0.32,
The lee end of the fin is located on the leeward side in the air flow direction further than the lee end of the flat multi-hole tube,
The heat exchanger according to claim 1. The fin lower end is located 2 mm or more away from the wind lower end of the flat multi-hole tube further to the leeward side,
The heat exchanger according to claim 2. Satisfies the relationship of 0.18 ≦ L / Wt ≦ 0.30,
The lee end of the flat multi-hole tube is located further on the leeward side in the air flow direction than the lee end of the fin,
The heat exchanger according to claim 1. Satisfies the relationship of 3 ≦ a / b ≦ 9.
The heat exchanger according to any one of claims 1 to 4. L ≧ 4 mm,
The heat exchanger according to any one of claims 1 to 5. The width (a1) in the air flow direction of the refrigerant channel on the most windward side of the flat multi-hole tube is equal to the width (b) in the air flow direction of the refrigerant channel at the center in the air flow direction of the flat multi-hole tube. 1.5 times or more,
The heat exchanger according to any one of claims 1 to 6.

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