Heat exchanger and refrigeration device

Abstract

A heat source-side heat exchanger (11) is provided with an upwind tube row (55) and a downwind tube row (56), fins (54), and a downwind upper header (80). The upwind tube row (55) and the downwind tube row (56) are aligned in the air flow direction, and are each formed by a plurality of flat tubes (52) extending in the vertical direction and aligned in the horizontal direction. The downwind upper header (80) is disposed at the upper end of the downwind tube row (56) and is in communication with the plurality of flat tubes (52) constituting the downwind tube row (56). The upward tube row (55) is segmented into a first upwind section (55a) and a second upwind section (55b). The downwind tube row (56) is segmented into a first downwind section (56a) and a second downwind section (56b). In a flow path of a refrigerant, the first upwind section (55a), the first downwind section (56a), the upwind upper header (80), the second downwind section (56b), and the second upwind section (55b) are disposed in series. The refrigerant flows sequentially from the first upwind section (55a) to the second upwind section (55b) when the heat exchanger is used as a condenser.

Description

Heat exchanger and refrigeration apparatus

[0001] The present invention relates to a heat exchanger and a refrigeration apparatus.

[0002] Conventionally, there has been a heat exchanger for an air conditioner including a plurality of heat exchangers arranged along an air flow direction, and a header to which a plurality of flat tubes are connected. For example, in Patent Document 1 (International Publication No. WO 2021 / 234953), a liquid pipe and a plurality of flat tubes are connected to one header provided at a lower end of an upwind heat exchanger, and a heat exchanger in which a gas pipe and a plurality of flat tubes are connected to another header provided at the lower end on the upwind side is disclosed.

[0003] Generally, in a heat exchanger that functions as a condenser during defrosting operation, frost at the lower part of the heat exchanger and in the vicinity of the liquid pipe tends to remain unmelted. In the heat exchanger disclosed in Patent Document 1, since the liquid pipe is connected to the lower part of the heat exchanger, there is a possibility that sufficient performance cannot be obtained in the defrosting operation.

[0004] A heat exchanger according to a first aspect includes an upwind tube row, a downwind tube row, fins, and a downwind upper header. The upwind tube row and the downwind tube row are each formed of a plurality of flat tubes. The plurality of flat tubes extend in a vertical direction and are arranged in a horizontal direction. The upwind tube row and the downwind tube row are arranged along the air flow direction. The flat tubes are joined to the fins in each of the upwind tube row and the downwind tube row. The downwind upper header is disposed at an upper end of the downwind tube row and communicates with the plurality of flat tubes constituting the downwind tube row.

[0005] The upwind tube row is divided into a first upwind upper portion and a second upwind upper portion. The first upwind upper portion and the second upwind upper portion are each formed of a plurality of flat tubes arranged in the horizontal direction. The downwind tube row is divided into a first downwind lower portion and a second downwind lower portion. The first downwind lower portion and the second downwind lower portion are each formed of a plurality of flat tubes arranged in the horizontal direction. In a refrigerant flow path, the first upwind upper portion, the first downwind lower portion, the downwind upper header, the second downwind lower portion, and the second upwind upper portion are arranged in series. When used as a condenser, the refrigerant flows sequentially from the first upwind upper portion to the second upwind upper portion.

[0006] In the first type of heat exchanger, when the heat exchanger functions as a condenser, the refrigerant inlet and outlet are located on the windward side and above the heat exchanger. In other words, the side where the liquid piping connection is most likely to retain frost during defrosting is located on the windward side and above the heat exchanger. This improves the efficiency of defrosting.

[0007] The heat exchanger in the second perspective is the same as the heat exchanger in the first perspective, and when used as an evaporator, the refrigerant flows sequentially from the second upstream side to the first upstream side.

[0008] In the second aspect of the heat exchanger, when the heat exchanger functions as an evaporator, the refrigerant inlet and outlet are positioned on the upwind and upper side of the heat exchanger. In other words, the side where frost is likely to form (liquid piping connection) is positioned on the upwind and upper side of the heat exchanger. This can delay frost formation.

[0009] The heat exchanger in the third aspect is a heat exchanger in the first or second aspect, and the refrigerant is a non-azeotropic mixed refrigerant.

[0010] When using non-azeotropic refrigerant mixtures, temperature glide tends to lower the refrigerant temperature at the evaporator inlet (liquid piping connection side), making frost formation more likely. Furthermore, frost formation generally tends to be greater at the bottom of the evaporator. In a third-party heat exchanger, frost formation can be delayed when using non-azeotropic refrigerant mixtures, improving the efficiency of defrost operation.

[0011] The heat exchanger of the fourth view is a heat exchanger of any of the first, third, or fourth views, further comprising an upwind upper header, a gas-side connecting pipe, and a liquid-side connecting pipe. The upwind upper header is located at the upper end of the upwind pipe row and communicates with a plurality of flat pipes. The internal space of the upwind upper header is divided by a partition plate into a first space communicating with the flat pipes constituting the first upwind section and a second space communicating with the flat pipes constituting the second upwind section. The gas-side connecting pipe is connected to the first space. The liquid-side connecting pipe is connected to the second space.

[0012] In the heat exchanger from the fourth perspective, the refrigerant inlet and outlet are positioned at the upper end of the windward pipe row, which delays frost formation and improves the efficiency of defrosting operation.

[0013] The heat exchanger in the fifth perspective is a heat exchanger in either the first or fourth perspective, where the number of flattened tubes constituting the first upstream section is the same as the number of flattened tubes constituting the first downstream section. The number of flattened tubes constituting the second upstream section is the same as the number of flattened tubes constituting the second downstream section.

[0014] The heat exchanger in the sixth perspective is a heat exchanger in either the first or fifth perspective, where the number of flattened tubes constituting the first upstream section is greater than the number of flattened tubes constituting the second upstream section. The number of flattened tubes constituting the first downstream section is greater than the number of flattened tubes constituting the second downstream section.

[0015] In the heat exchanger of the sixth perspective, the number of flattened tubes in the first upstream and first downstream sections on the gaseous refrigerant inlet / outlet side of the refrigerant flow path is greater than the number of flattened tubes in the second upstream and second downstream sections on the liquid refrigerant inlet / outlet side. Also, the volume per unit mass is greater for gaseous refrigerant than for liquid refrigerant. With this configuration, the heat exchanger of the sixth perspective can suppress refrigerant flow deviation.

[0016] The heat exchanger of the seventh aspect is a heat exchanger of any of the first to sixth aspects, further comprising a lower header. The lower header is located at the lower end of the upwind and downwind rows of tubes. The lower header communicates with a plurality of flattened tubes constituting the upwind row and a plurality of flattened tubes constituting the downwind row.

[0017] The refrigeration system of the eighth aspect comprises a heat exchanger of any of the first or seventh aspects.

[0018] This is a schematic diagram of an air conditioning system according to one embodiment of a refrigeration system. This is a schematic external perspective view of the heat source unit. This is a schematic plan view of the heat source unit (illustrations of refrigerant circuit components other than the heat source side heat exchanger and the fan module are omitted). This is a schematic perspective view of a part of the heat source side heat exchanger. This is a diagram conceptually showing the flow of refrigerant in the heat source side heat exchanger. This is a diagram conceptually showing the flow of refrigerant in the second upstream and second downstream sections. This is a diagram conceptually showing the flow of refrigerant in the first upstream and first downstream sections.

[0019] The following describes embodiments of the refrigeration system and its modifications with reference to the drawings.

[0020] (1) Overall configuration diagram 1 is a schematic configuration diagram of an air conditioning system 1 according to one embodiment of a refrigeration system.

[0021] The air conditioning system 1 is a device capable of cooling and heating a space to be air-conditioned by performing a vapor compression type refrigeration cycle.

[0022] The air conditioning system 1 mainly comprises a heat source unit 2, utilization units 3a and 3b, a liquid refrigerant connecting pipe 4 and a gas refrigerant connecting pipe 5, and a control unit 23. The liquid refrigerant connecting pipe 4 and the gas refrigerant connecting pipe 5 connect the heat source unit 2 and the utilization units 3a and 3b. In the air conditioning system 1, the heat source unit 2 and the utilization units 3a and 3b are connected via the refrigerant connecting pipes 4 and 5 to form a vapor compression type refrigerant circuit 6. The refrigerant sealed in the refrigerant circuit 6 is a non-azeotropic mixed refrigerant, for example, R454C. A non-azeotropic mixed refrigerant is a mixture of multiple types of refrigerants with different boiling points. However, the type of refrigerant may be a single refrigerant such as R32, HFO1234yf, HFO1234ze(E) or a mixture thereof, or a natural refrigerant. The control unit 23 controls the components of the heat source unit 2 and the utilization units 3a and 3b.

[0023] In Figure 1, the air conditioning system 1 has one heat source unit 2 and two utilization units 3a and 3b, but the number of units is merely illustrative. The air conditioning system 1 may have multiple heat source units, or one or three or more utilization units.

[0024] (2) Detailed Configuration (2-1) Heat Source Unit The equipment constituting the heat source unit 2 will be described below. Details regarding the shape and structure of the heat source unit 2, and the configuration of the heat source side heat exchanger 11 and the surrounding area of ​​the heat source side heat exchanger 11 will be described separately later.

[0025] The heat source unit 2 is installed, for example, outdoors. While the installation location is not limited, the heat source unit 2 is installed, for example, on the roof of a building or near the wall of a building.

[0026] The heat source unit 2 mainly comprises an accumulator 7, a compressor 8, a flow path switching mechanism 10, a heat source side heat exchanger 11, a heat source side expansion mechanism 12, a liquid side shut-off valve 13, a gas side shut-off valve 14, and a heat source side fan 15.

[0027] The heat source unit 2 also includes an intake pipe 17, a discharge pipe 18, a first gas refrigerant pipe 19, a liquid refrigerant pipe 20, and a second gas refrigerant pipe 21. The intake pipe 17 connects the flow path switching mechanism 10 to the intake side of the compressor 8. An accumulator 7 is provided in the intake pipe 17. The discharge pipe 18 connects the discharge side of the compressor 8 to the flow path switching mechanism 10. The first gas refrigerant pipe 19 connects the flow path switching mechanism 10 to the gas side end of the heat source side heat exchanger 11. The liquid refrigerant pipe 20 connects the liquid side end of the heat source side heat exchanger 11 to the liquid side shut-off valve 13. The heat source side expansion mechanism 12 is provided in the liquid refrigerant pipe 20. The second gas refrigerant pipe 21 connects the flow path switching mechanism 10 to the gas side shut-off valve 14.

[0028] (2-1-1) Compressor The compressor 8 is a device that inhales low-pressure refrigerant, compresses it, and discharges it. The compressor 8 is an inverter-controlled compressor with adjustable motor speed (adjustable capacity). The rotation speed of the compressor 8 is adjusted by the control unit 23 according to the operating conditions. The compressor 8 may also be a compressor with a constant motor speed.

[0029] (2-1-2) Flow path switching mechanism The flow path switching mechanism 10 is a mechanism that switches the flow direction of the refrigerant in the refrigerant circuit 6 according to the operating mode (cooling operation mode / heating operation mode). In this embodiment, the flow path switching mechanism 10 is a four-way switching valve.

[0030] In cooling operation mode, the flow path switching mechanism 10 switches the direction of refrigerant flow in the refrigerant circuit 6 so that the refrigerant discharged by the compressor 8 is sent to the heat source side heat exchanger 11. Specifically, in cooling operation mode, the flow path switching mechanism 10 connects the suction pipe 17 to the second gas refrigerant pipe 21 and the discharge pipe 18 to the first gas refrigerant pipe 19 (see solid line in Figure 1). In heating operation mode, the flow path switching mechanism 10 switches the direction of refrigerant flow in the refrigerant circuit 6 so that the refrigerant discharged by the compressor 8 is sent to the utilization side heat exchangers 32a and 32b. Specifically, in heating operation mode, the flow path switching mechanism 10 connects the suction pipe 17 to the first gas refrigerant pipe 19 and the discharge pipe 18 to the second gas refrigerant pipe 21 (see dashed line in Figure 1).

[0031] Furthermore, the flow path switching mechanism 10 is not limited to a four-way switching valve, but may be configured to combine multiple solenoid valves and refrigerant pipes to achieve the above-described switching of the refrigerant flow direction.

[0032] (2-1-3) Heat Source Side Heat Exchanger The heat source side heat exchanger 11 is an example of a heat exchanger. The heat source side heat exchanger 11 functions as a condenser (heat radiator) during cooling operation and as an evaporator (heat absorber) during heating operation. The heat source side heat exchanger 11 will be explained in detail later.

[0033] (2-1-4) Heat source side expansion mechanism The heat source side expansion mechanism 12 is a mechanism for expanding the refrigerant. Although not limited thereto, in this embodiment the heat source side expansion mechanism 12 is an electronic expansion valve with adjustable opening. The opening of the heat source side expansion mechanism 12 is appropriately adjusted by the control unit 23 according to the operating conditions.

[0034] (2-1-5) Heat source side fan The heat source side fan 15 is a blower that generates an airflow that flows into the heat source unit 2 from the outside, passes through the heat source side heat exchanger 11, and flows out to the outside of the heat source unit 2. The heat source side fan 15 is controlled by the control unit 23 and its rotation speed is adjusted as appropriate. In this embodiment, although not limited thereto, the heat source side fan 15 is a propeller fan.

[0035] (2-2) Usage Units The usage units 3a and 3b are installed in a room. The usage units 3a and 3b are installed, for example, in a living space that is an air-conditioned space, or in the space above the ceiling of a living space.

[0036] The utilization unit 3a mainly comprises a utilization-side expansion mechanism 31a, a utilization-side heat exchanger 32a, and a utilization-side fan 33a. The utilization unit 3b mainly comprises a utilization-side expansion mechanism 31b, a utilization-side heat exchanger 32b, and a utilization-side fan 33b.

[0037] (2-2-1) User-side expansion mechanism The user-side expansion mechanisms 31a and 31b are mechanisms for expanding the refrigerant. Although not limited to these, in this embodiment the user-side expansion mechanisms 31a and 31b are electronic expansion valves with adjustable opening degrees. The opening degrees of the user-side expansion mechanisms 31a and 31b are appropriately adjusted by the control unit 23 according to the operating conditions.

[0038] (2-2-2) User-side heat exchangers User-side heat exchangers 32a and 32b are heat exchangers that function as evaporators to cool indoor air during cooling operation and as refrigerant condensers to heat indoor air during heating operation. The liquid side of user-side heat exchangers 32a and 32b is connected to the liquid refrigerant connecting pipe 4, and the gas side of user-side heat exchangers 32a and 32b is connected to the gas refrigerant connecting pipe 5. User-side heat exchangers 32a and 32b are, for example, cross-fin type fin-and-tube heat exchangers composed of heat transfer tubes (not shown) and a large number of fins (not shown).

[0039] (2-2-3) User-side fans The user-side fans 33a and 33b draw in indoor air into the user units 3a and 3b and supply the air that has passed through the user-side heat exchangers 32a and 32b to the room. The user-side fans 33a and 33b are controlled by the control unit 23 and their rotation speed is adjusted as appropriate. The user-side fans 33a and 33b are, for example, centrifugal fans.

[0040] (2-3) Refrigerant connection pipes The refrigerant connection pipes 4 and 5 are refrigerant pipes constructed on site when the air conditioner 1 is installed. One end of the liquid refrigerant connection pipe 4 is connected to the liquid-side stop valve 13 of the heat source unit 2, and the other end of the liquid refrigerant connection pipe 4 is connected to the liquid side of the usage-side expansion mechanisms 31a, 31b of the usage units 3a, 3b. One end of the gas refrigerant connection pipe 5 is connected to the gas-side stop valve 14 of the heat source unit 2, and the other end of the gas refrigerant connection pipe 5 is connected to the gas side of the usage-side heat exchangers 32a, 32b of the usage units 3a, 3b.

[0041] (2-4) Control unit The control unit 23 is configured by communicably connecting a control board (not shown) having a CPU, ROM, RAM and the like provided in the heat source unit 2 and the usage units 3a, 3b. In FIG. 1, for convenience, the control unit 23 is illustrated at a position separated from the heat source unit 2 and the usage units 3a, 3b.

[0042] The control unit 23 is electrically connected to the constituent devices of the air conditioner 1 as indicated by the dotted line in FIG. 1. The control unit 23, by executing a program for operation control of the air conditioner 1 (by the CPU executing a program stored in the ROM), controls the constituent devices of the air conditioner 1 based on operations of a remote controller (not shown), measurement values of sensors (not shown), and the like. The constituent devices of the air conditioner 1 controlled by the control unit 23 include, for example, the compressor 8, the flow path switching mechanism 10, the heat source-side expansion mechanism 12 and the heat source-side fan 15 of the heat source unit 2, and the usage-side expansion mechanisms 31a, 31b and the usage-side fans 33a, 33b of the usage units 3a, 3b.

[0043] (3) Operation of the air conditioner Next, the operation of the air conditioner 1 will be described with reference to FIG. 1.

[0044] In the air conditioner 1, a cooling operation and a heating operation are performed. During the cooling operation, the refrigerant circulates in the order of the compressor 8, the heat source-side heat exchanger 11, the heat source-side expansion mechanism 12, the usage-side expansion mechanisms 31a, 31b, and the usage-side heat exchangers 32a, 32b. During the heating operation, the refrigerant circulates in the order of the compressor 8, the usage-side heat exchangers 32a, 32b, the usage-side expansion mechanisms 31a, 31b, the heat source-side expansion mechanism 12, and the heat source-side heat exchanger 11.

[0045] Furthermore, in the air conditioning system 1, during heating operation, the heating operation is temporarily interrupted and a defrost operation is performed to melt the frost that has accumulated on the heat source side heat exchanger 11. In this embodiment, as the defrost operation, a reverse cycle defrost operation is performed in which the refrigerant is circulated in the same order as during cooling operation: compressor 8, heat source side heat exchanger 11, heat source side expansion mechanism 12 and user side expansion mechanisms 31a, 31b, and user side heat exchangers 32a, 32b. During cooling operation, heating operation, and defrost operation, the components of the air conditioning system 1 are controlled by the control unit 23.

[0046] During cooling operation, the flow path switching mechanism 10 is switched to the state shown by the solid line in Figure 1. In the refrigerant circuit 6, the low-pressure gaseous refrigerant of the refrigeration cycle is drawn into the compressor 8, compressed until it reaches the high pressure of the refrigeration cycle, and then discharged. The high-pressure gaseous refrigerant discharged from the compressor 8 is sent to the heat source side heat exchanger 11 through the flow path switching mechanism 10. The high-pressure gaseous refrigerant sent to the heat source side heat exchanger 11, which functions as a refrigerant condenser, exchanges heat with the outdoor air supplied as a cooling source by the heat source side fan 15, and dissipates heat, becoming high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has dissipated heat in the heat source side heat exchanger 11 is sent to the user side expansion mechanisms 31a and 31b through the heat source side expansion mechanism 12, the liquid side shut-off valve 13, and the liquid refrigerant connecting pipe 4. The refrigerant sent to the user-side expansion mechanisms 31a and 31b is reduced in pressure to the low pressure of the refrigeration cycle by the user-side expansion mechanisms 31a and 31b, becoming a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant reduced in pressure by the user-side expansion mechanisms 31a and 31b is sent to the user-side heat exchangers 32a and 32b. The low-pressure gas-liquid two-phase refrigerant sent to the user-side heat exchangers 32a and 32b exchanges heat with the indoor air supplied as a heat source by the user-side fans 33a and 33b and evaporates. As a result, the indoor air is cooled, and after cooling, it is supplied to the room to cool the room. The low-pressure gaseous refrigerant evaporated in the user-side heat exchangers 32a and 32b is drawn back into the compressor 8 through the gas-refrigerant connecting pipe 5, the gas-side shut-off valve 14, the flow path switching mechanism 10, and the accumulator 7.

[0047] During heating operation, the flow path switching mechanism 10 is switched to the state shown by the broken line in FIG. 1. In the refrigerant circuit 6, the low-pressure gas refrigerant of the refrigeration cycle is sucked into the compressor 8, compressed until it reaches high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the usage-side heat exchangers 32a and 32b through the flow path switching mechanism 10, the gas-side stop valve 14, and the gas refrigerant connection pipe 5. The high-pressure gas refrigerant sent to the usage-side heat exchangers 32a and 32b exchanges heat with indoor air supplied as a cooling source by the usage-side fans 33a and 33b in the usage-side heat exchangers 32a and 32b to dissipate heat, and becomes high-pressure liquid refrigerant. Accordingly, the indoor air is heated, and after being heated, it is supplied into the room to heat the room. The high-pressure liquid refrigerant that has dissipated heat in the usage-side heat exchangers 32a and 32b is sent to the heat-source-side expansion mechanism 12 through the usage-side expansion mechanisms 31a and 31b, the liquid refrigerant connection pipe 4, and the liquid-side stop valve 13. The refrigerant sent to the heat-source-side expansion mechanism 12 is depressurized to the low pressure of the refrigeration cycle by the heat-source-side expansion mechanism 12, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant depressurized by the heat-source-side expansion mechanism 12 is sent to the heat-source-side heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant sent to the heat-source-side heat exchanger 11 exchanges heat with outdoor air supplied as a heating source by the heat-source-side fan 15 in the heat-source-side heat exchanger 11 functioning as a refrigerant evaporator, evaporates, and becomes low-pressure gas refrigerant. The low-pressure gas refrigerant evaporated in the heat-source-side heat exchanger 11 is sucked into the compressor 8 again through the flow path switching mechanism 10 and the accumulator 7.

[0048] In the above heating operation, when a condition for starting defrosting of the heat-source-side heat exchanger 11 is satisfied, a defrosting operation for melting frost adhering to the heat-source-side heat exchanger 11 is performed. The case where the condition for starting defrosting of the heat-source-side heat exchanger 11 is satisfied is, for example, when frost formation on the heat-source-side heat exchanger 11 is detected because the temperature of the refrigerant in the heat-source-side heat exchanger 11 becomes lower than a predetermined temperature.

[0049] Defrosting is performed by switching the flow path switching mechanism 10 to the state shown by the solid line in Figure 1, similar to cooling operation, to allow the heat source side heat exchanger 11 to function as a refrigerant condenser. This melts the frost that has accumulated on the heat source side heat exchanger 11. Defrosting is performed until the set defrosting time, which takes into account the state of heating operation before defrosting, has elapsed, or until it is determined that defrosting of the heat source side heat exchanger 11 is complete, such as when the temperature of the refrigerant in the heat source side heat exchanger 11 rises above a predetermined temperature. After the defrosting operation is completed, the air conditioning system 1 returns to heating operation. Note that the flow of refrigerant in the refrigerant circuit 6 during defrosting is the same as during cooling operation, so a detailed explanation is omitted here.

[0050] (4) Overall configuration of the heat source unit Next, the shape and structure of the heat source unit 2 will be described.

[0051] Figure 2 is a schematic external perspective view of the heat source unit 2. Figure 3 is a schematic plan view of the heat source unit 2 (refrigerant circuit components other than the heat source side heat exchanger 11 and the fan module 44, which will be described later, are not shown).

[0052] In the following explanation, expressions such as "up," "down," "left," "right," "front," "back," "front view," and "rear view" may be used to describe directions and positional relationships. Unless otherwise specified, the directions indicated by these expressions follow the directions of the arrows shown in the drawings.

[0053] The heat source unit 2 is an upward-blowing type heat exchange unit that draws in air from the side of the casing 40, passes the air through the heat source side heat exchanger 11, and blows the air out from the top of the casing 40.

[0054] The heat source unit 2 mainly consists of a roughly rectangular box-shaped casing 40, a heat source side fan 15, and refrigerant circuit components that constitute part of the refrigerant circuit 6. The refrigerant circuit components of the heat source unit 2 include an accumulator 7, a compressor 8, a heat source side heat exchanger 11, a flow path switching mechanism 10, a heat source side expansion mechanism 12, a liquid side shut-off valve 13, and a gas side shut-off valve 14. The heat source side fan 15 and the refrigerant circuit components are housed in the casing 40.

[0055] Air intake ports 40a are formed on the back and both left and right sides of the casing 40, and an air outlet port 40b is formed on the top surface. The bottom frame 42 forms the bottom surface of the casing 40. The heat source side heat exchanger 11, compressor 8, accumulator 7, etc. are arranged on the bottom frame 42. The heat source side heat exchanger 11 is a heat exchanger with a roughly U-shape in plan view that faces the back and both left and right sides of the casing 40, and substantially forms the back and both left and right sides of the casing 40. The front panel 45 forms the front surface of the casing 40. In addition to being a frame on which the heat source side heat exchanger 11 etc. are arranged, the bottom frame 42 also functions as a drain pan that receives drain water generated in the heat source side heat exchanger 11 during cooling operation or defrosting operation.

[0056] A fan module 44 is provided above the heat source side heat exchanger 11 (upper part of the casing 40) (see Figure 2). The fan module 44 is an assembly in which the heat source side fan 15 is housed in a roughly rectangular box-shaped body with openings on the top and bottom. The opening on the top of the fan module 44 is the air outlet 40b of the casing 40. A discharge grille 46 is provided at the air outlet 40b. The heat source side fan 15 is positioned inside the casing 40 facing the air outlet 40b. The heat source side fan 15 is a blower that takes in air into the casing 40 from the air intake 40a and discharges it from the air outlet 40b.

[0057] (5) Detailed Structure of the Heat Source Side Heat Exchanger The heat source side heat exchanger 11 is a heat exchanger that performs heat exchange between the refrigerant and the outdoor air. Figure 4 is a schematic perspective view of a part of the heat source side heat exchanger 11 as seen from the upwind side. Figure 5 is a diagram conceptually showing the flow of the refrigerant in the heat source side heat exchanger 11. Figure 6A is a diagram conceptually showing the flow of the refrigerant in the second upwind section 55b and the second downwind section 56b. Figure 6B is a diagram conceptually showing the flow of the refrigerant in the first upwind section 55a and the first downwind section 56a. Note that Figures 4 to 6B are schematic diagrams to explain the flat tubes 52 and fins 54 that constitute the heat source side heat exchanger 11 and the flow of the refrigerant in the heat source side heat exchanger 11, and do not accurately show the structure and shape of the heat source side heat exchanger 11, etc. Furthermore, the arrows indicating the refrigerant flow shown in Figures 5, 6A, and 6B represent the refrigerant flow direction during heating operation (when the heat source side heat exchanger 11 functions as a refrigerant evaporator). During cooling operation and defrosting operation, the refrigerant flows in the opposite direction to the arrows indicating the refrigerant flow shown in Figures 5, 6A, and 6B.

[0058] The heat source side heat exchanger 11 mainly has multiple rows (in this case, two rows) of heat exchange sections 50 (upwind side heat exchange section 50a and downwind side heat exchange section 50b), an upwind upper header 70, a downwind upper header 80, and a lower header 75.

[0059] The upwind heat exchange section 50a and the downwind heat exchange section 50b are arranged in the direction of airflow generated by the heat source fan 15. Specifically, the upwind heat exchange section 50a is located on the upwind side, and the downwind heat exchange section 50b is located on the downwind side. Each heat exchange section 50 has a plurality of flattened tubes 52 and a plurality of fins 54 to which the plurality of flattened tubes 52 are joined. Each of the plurality of flattened tubes 52 extends vertically and is arranged horizontally. The flattened tubes 52 may be arranged straight horizontally or along a curved line. Hereinafter, the plurality of flattened tubes 52 constituting the upwind heat exchange section 50a will be called the upwind tube row 55, and the plurality of flattened tubes 52 constituting the downwind heat exchange section 50b will be called the downwind tube row 56. The heat exchange section 50, the upwind upper header 70, the downwind upper header 80, and the lower header 75 are joined to each other by brazing or the like.

[0060] The flattened tube 52 is a flattened, multi-hole tube having two flat surfaces that serve as heat transfer surfaces and passages consisting of numerous small through-holes through which the refrigerant formed inside flows (not shown). Fins 54 are joined to the flattened tubes 52 of the upwind tube row 55 and the flattened tubes 52 of the downwind tube row 56, respectively.

[0061] The fins 54 are components that increase the heat transfer area of ​​the heat source side heat exchanger 11. The fins 54 divide the space between adjacent horizontally adjacent flat pipes 52 into multiple air passages through which air flows. The fins 54 are arranged to connect to adjacent flat pipes 52. For example, corrugated fins are used for the fins 54.

[0062] The upwind upper header 70 is located at the upper end of the upwind heat exchange section 50a of the heat source side heat exchanger 11. In other words, the upwind upper header 70 is located at the upper end of the upwind pipe row 55. The upwind upper header 70 is a hollow member with both ends closed. The internal space of the upwind upper header 70 is divided into a first space SP1 and a second space SP2 by a first partition plate 71 that extends vertically (see Figure 5). The first partition plate 71 is an example of a partition plate. The first space SP1 is the space to the left of the first partition plate 71. The second space SP2 is the space to the right of the first partition plate 71. Each of the flat pipes 52 of the upwind pipe row 55 is connected to the first space SP1 and the second space SP2, respectively (see Figures 6A and 6B). In other words, the internal space of the upwind upper header 70 and each of the flat pipes 52 of the upwind pipe row 55 are in communication. Hereinafter, the multiple flat pipes 52 communicating with the first space SP1 will be referred to as the first upstream section 55a, and the multiple flat pipes 52 communicating with the second space SP2 will be referred to as the second upstream section 55b. The first space SP1 is connected to the first gas refrigerant pipe 19 of the refrigerant circuit 6 via a gas-side connecting pipe 72. The second space SP2 is connected to the liquid refrigerant pipe 20 of the refrigerant circuit 6 via a liquid-side connecting pipe 73. Although the connection method is not limited, the upstream header 70, each flat pipe 52 of the upstream pipe row 55, the gas-side connecting pipe 72, and the liquid-side connecting pipe 73 are joined by brazing.

[0063] The downwind upper header 80 is located at the upper end of the downwind heat exchange section 50b of the heat source side heat exchanger 11. In other words, the downwind upper header 80 is located at the upper end of the downwind pipe row 56. The downwind upper header 80 is a hollow member with both ends closed. The internal space of the downwind upper header 80 is divided into a third space SP3 and a fourth space SP4 by a second partition plate 81 that extends vertically (see Figure 5). The third space SP3 is the space to the left of the second partition plate 81. The fourth space SP4 is the space to the right of the second partition plate 81. Each flat pipe 52 of the downwind pipe row 56 is connected to the downwind upper header 80 (see Figures 6A and 6B). In other words, the internal space of the downwind upper header 80 and each flat pipe 52 of the downwind pipe row 56 are in communication. Hereinafter, the multiple flat pipes 52 communicating with the third space SP3 will be referred to as the first leeward section 56a, and the multiple flat pipes 52 communicating with the fourth space SP4 will be referred to as the second leeward section 56b. One end of the connecting pipe 84 is connected to the third space SP3, and the other end of the connecting pipe 84 is connected to the fourth space SP4. The connecting pipe 84 is a pipe for connecting the third space SP3 and the fourth space SP4. In other words, the third space SP3 and the fourth space SP4 are in communication. Although Figure 5 shows one connecting pipe 84 connecting the third space SP3 and the fourth space SP4, two or more connecting pipes 84 may be provided. The connection method is not limited, but the leeward upper header 80, each flat pipe 52 constituting the leeward pipe row 56, and the connecting pipe 84 are joined by brazing.

[0064] The lower header 75 is located at the lower ends of the upwind heat exchange section 50a and the downwind heat exchange section 50b. In other words, the lower header 75 is located at the lower ends of the upwind pipe row 55 and the downwind pipe row 56. The lower header 75 is a hollow member with both ends closed. The flat pipes 52 of the upwind pipe row 55 and the downwind pipe row 56 are connected to the lower header 75 (see Figures 6A and 6B). In other words, the internal space of the lower header 75 is in communication with the flat pipes 52 of the upwind pipe row 55 and the downwind pipe row 56. The internal space of the lower header 75 is divided into a fifth space SP5 and a sixth space SP6 by a third partition plate 76 that extends vertically (see Figure 5). The fifth space SP5 is the space to the left of the third partition plate 76. The sixth space SP6 is the space to the right of the third partition plate 76. The fifth space SP5 is connected to the flat pipe 52 of the first upwind section 55a and the flat pipe 52 of the first downwind section 56a. In other words, the fifth space SP5 is in communication with the flat pipe 52 of the first upwind section 55a and the flat pipe 52 of the first downwind section 56a. Also, the sixth space SP6 is connected to the flat pipe 52 of the second upwind section 55b and the flat pipe 52 of the second downwind section 56b. In other words, the sixth space SP6 is in communication with the flat pipe 52 of the first upwind section 55a and the flat pipe 52 of the first downwind section 56a. With this configuration, the lower header 75 connects the first ends of the upwind pipe row 55 and the downwind pipe row 56 (the first end 55a1 of the first upwind section 55a and the first end 56a1 of the first downwind section 56a, or the first end 55b1 of the second upwind section 55b and the first end 56b1 of the second downwind section 56b).

[0065] Furthermore, the lower header 75 may have its internal space (the fifth space SP5 and the sixth space SP6) further divided into multiple sections in the extending direction by a plurality of partition plates (not shown) that extend vertically. Although not limited to the connection method, the lower header 75 and each of the flat pipes 52 in the upwind pipe row 55 and each of the flat pipes 52 in the downwind pipe row 56 are joined by brazing.

[0066] Each flattened pipe 52 in the upwind pipe row 55 has one end connected to the upwind upper header 70 and the other end connected to the lower header 75 (see Figure 4). Specifically, each flattened pipe 52 in the first upwind section 55a has one end (the second end 55a2 side of the first upwind section 55a) connected to the first space SP1 of the upwind upper header 70 and the other end (the first end 55a1 side of the first upwind section 55a) connected to the fifth space SP5 of the lower header 75 (see Figure 6B). Each flattened pipe 52 constituting the second upwind section 55b has one end (the second end 55b2 side of the second upwind section 55b) connected to the second space SP2 of the upwind upper header 70 and the other end (the first end 55b1 side of the second upwind section 55b) connected to the sixth space SP6 of the lower header 75 (see Figure 6A).

[0067] Each flattened pipe 52 in the downwind pipe row 56 is connected at one end to the downwind upper header 80 and at the other end to the lower header 75 (see Figure 4). Specifically, each flattened pipe 52 constituting the first downwind section 56a is connected at one end (the second end 56a2 of the first downwind section 56a) to the third space SP3 of the downwind upper header 80 and at the other end (the first end 56a1 of the first downwind section 56a) to the fifth space SP5 of the lower header 75 (see Figure 6B). Each flattened pipe 52 constituting the second downwind section 56b is connected at one end (the second end 56b2 of the second downwind section 56b) to the fourth space SP4 of the downwind upper header 80 and at the other end (the first end 56b1 of the second downwind section 56b) to the sixth space SP6 of the lower header 75 (see Figure 6A).

[0068] With the above configuration, the first upstream section 55a, the first downstream section 56a, the downstream upper header 80, the second downstream section 56b, and the second upstream section 55b are arranged in series in the refrigerant flow path.

[0069] Furthermore, the number of flattened pipes 52 in the first upwind section 55a is the same as the number of flattened pipes 52 in the first downwind section 56a. Also, the number of flattened pipes 52 in the second upwind section 55b is the same as the number of flattened pipes 52 in the second downwind section 56b.

[0070] The number of flattened pipes 52 in the first upwind section 55a is greater than the number of flattened pipes 52 in the second upwind section 55b. Also, the number of flattened pipes 52 in the first leeward section 56a is greater than the number of flattened pipes 52 in the second leeward section 56b. In other words, the number of flattened pipes 52 in the first upwind section 55a is greater than 50% of the total number of flattened pipes 52 in the upwind pipe row 55. Also, the number of flattened pipes 52 in the first leeward section 56a is greater than 50% of the total number of flattened pipes 52 in the leeward pipe row 56. It is more preferable that the number of flattened pipes 52 in the first upwind section 55a is between 70% and 80 of the total number of flattened pipes 52 in the upwind pipe row 55. It is also more preferable that the number of flattened pipes 52 in the first leeward section 56a is between 70% and 80 of the total number of flattened pipes 52 in the leeward pipe row 56.

[0071] (6) Refrigerant flow The refrigerant flow in the heat source side heat exchanger 11 having the above configuration will be described.

[0072] (6-1) Heating Operation During heating operation, the heat source side heat exchanger 11 functions as an evaporator for the refrigerant that has been depressurized in the heat source side expansion mechanism 12. During heating operation, the refrigerant flows in the direction of the arrows showing the flow of the refrigerant in Figures 5, 6A, and 6B.

[0073] The refrigerant, depressurized in the heat source side expansion mechanism 12, flows through the liquid refrigerant pipe 20 of the refrigerant circuit 6 and is sent to the second space SP2 of the upwind upper header 70 via the liquid side connecting pipe 73 (FL1). The refrigerant sent to the second space SP2 is divided into a plurality of flat pipes 52 (flat pipes 52 of the second upwind 55b) that communicate with the second space SP2. The refrigerant that flows downward through the flat pipes 52 of the second upwind 55b is sent to the sixth space SP6 of the lower header 75 (FL2). The refrigerant sent to the sixth space SP6 flows into the flat pipes 52 of the second downwind 56b that communicate with the sixth space SP6 (FL3). The refrigerant that flows upward through the flat pipes 52 of the second downwind 56b is sent to the fourth space SP4 of the downwind upper header 80 (FL4). The refrigerant sent to the fourth space SP4 is sent to the third space SP3 of the downwind upper header 80 via the connecting pipe 84 (FL5). The refrigerant sent to the third space SP3 is divided into a plurality of flat pipes 52 (flat pipes 52 of the first downwind 56a) that communicate with the third space SP3. The refrigerant that flows downward through the flat pipes 52 of the first downwind 56a is sent to the fifth space SP5 of the lower header 75 (FL6). The refrigerant sent to the fifth space SP5 flows into the flat pipes 52 of the first upwind 55a that communicate with the fifth space SP5 (FL7). The refrigerant that flows upward through the flat pipes 52 of the first upwind 55a is sent to the first space SP1 of the upwind upper header 70 (FL8). The refrigerant sent to the first space SP1 is sent to the compressor 8 via the gas-side connecting pipe 72 and the first gas refrigerant pipe 19 of the refrigerant circuit 6 (FL9).

[0074] As described above, when the heat source side heat exchanger 11 is used as an evaporator, the refrigerant flows sequentially from the second upstream side 55b to the first upstream side 55a. In this case, in the section where the refrigerant flows sequentially from the first downstream side 56a to the first upstream side 55a, the airflow and the refrigerant flow in the heat source side heat exchanger 11 form a counterflow relationship as a whole.

[0075] (6-2) Cooling Operation During cooling operation, the heat source side heat exchanger 11 functions as a condenser for the refrigerant discharged from the compressor 8. During cooling operation, the refrigerant flows in the opposite direction to the arrows indicating the flow of refrigerant in Figures 5, 6A, and 6B.

[0076] The refrigerant discharged from the compressor 8 flows through the first gas refrigerant pipe 19 of the refrigerant circuit 6 and is sent to the first space SP1 of the upwind upper header 70 via the gas-side connecting pipe 72 (FL9). The refrigerant sent to the first space SP1 is divided into a plurality of flat pipes 52 (flat pipes 52 of the first upwind 55a) that communicate with the first space SP1. The refrigerant that flows downward through the flat pipes 52 of the first upwind 55a is sent to the fifth space SP5 of the lower header 75 (FL8). The refrigerant sent to the fifth space SP5 flows into the flat pipes 52 of the first downwind 56a that communicate with the fifth space SP5 (FL7). The refrigerant that flows upward through the flat pipes 52 of the first downwind 56a is sent to the third space SP3 of the downwind upper header 80 (FL6). The refrigerant sent to the third space SP3 is sent to the fourth space SP4 of the downwind upper header 80 via the connecting pipe 84 (FL5). The refrigerant sent to the fourth space SP4 is divided into a plurality of flat pipes 52 (flat pipes 52 of the second downwind 56b) that communicate with the fourth space SP4. The refrigerant that flows downward through the flat pipes 52 of the second downwind 56b is sent to the sixth space SP6 of the lower header 75 (FL4). The refrigerant sent to the sixth space SP6 flows into the flat pipes 52 of the second upwind 55b that communicate with the sixth space SP6 (FL3). The refrigerant that flows upward through the flat pipes 52 of the second upwind 55b is sent to the second space SP2 of the upwind upper header 70 (FL2). The refrigerant sent to the second space SP2 is then sent to the heat source side expansion mechanism 12 (FL1) through the liquid side connecting pipe 73 and the liquid refrigerant pipe 20 of the refrigerant circuit 6.

[0077] As described above, when the heat source side heat exchanger 11 is used as a condenser, the refrigerant flows sequentially from the first upstream side 55a to the second upstream side 55b. In this case, in the section where the refrigerant flows sequentially from the second downstream side 56b to the second upstream side 55b, the airflow and the refrigerant flow in the heat source side heat exchanger 11 form a counterflow relationship as a whole.

[0078] During defrost operation, the heat source side heat exchanger 11 functions as a condenser for the refrigerant discharged from the compressor 8, similar to the cooling operation. The refrigerant flow in the heat source side heat exchanger 11 during defrost operation is the same as during cooling operation, so a detailed explanation is omitted here.

[0079] (7) Features (7-1) The heat source side heat exchanger 11 of this embodiment comprises an upwind pipe row 55 and a downwind pipe row 56, fins 54, and a downwind upper header 80. The upwind pipe row 55 and the downwind pipe row 56 are each composed of a plurality of flat pipes 52. The plurality of flat pipes 52 extend vertically and are arranged horizontally. The upwind pipe row 55 and the downwind pipe row 56 are arranged in the direction of airflow. The fins 54 are joined to the flat pipes 52 in each of the upwind pipe row 55 and the downwind pipe row 56. The downwind upper header 80 is located at the upper end of the downwind pipe row 56 and communicates with the plurality of flat pipes 52 that constitute the downwind pipe row 56. The upwind pipe row 55 is divided into a first upwind section 55a and a second upwind section 55b. The first upstream section 55a and the second upstream section 55b are each composed of multiple flattened pipes 52 arranged horizontally. The downwind pipe row 56 is divided into the first downstream section 56a and the second downstream section 56b. The first downstream section 56a and the second downstream section 56b are each composed of multiple flattened pipes 52 arranged horizontally. In the refrigerant flow path, the first upstream section 55a, the first downstream section 56a, the downwind upper header 80, the second downstream section 56b, and the second upstream section 55b are arranged in series. When used as a condenser, the refrigerant flows sequentially from the first upstream section 55a to the second upstream section 55b.

[0080] With this configuration, when the heat source side heat exchanger 11 functions as a condenser, the refrigerant inlet and outlet are located on the windward side and above the heat source side heat exchanger 11. In other words, the side where frost that has accumulated during defrosting operation is likely to remain is located on the windward side and above the heat source side heat exchanger 11. This improves the efficiency of defrosting operation.

[0081] (7-2) When the heat source side heat exchanger 11 of this embodiment is used as an evaporator, the refrigerant flows sequentially from the second upstream side 55b to the first upstream side 55a.

[0082] With this configuration, when the heat source side heat exchanger 11 functions as an evaporator, the refrigerant inlet and outlet are located on the windward side and above the heat source side heat exchanger 11. In other words, the side where frost is likely to form is located on the windward side and above the heat source side heat exchanger 11. This delays frost formation. Furthermore, whether the heat source side heat exchanger 11 functions as a condenser or an evaporator, the airflow and the refrigerant flow in the heat source side heat exchanger 11 form a counterflow relationship overall, thereby improving heat exchange efficiency.

[0083] (7-3) In the heat source side heat exchanger 11 of this embodiment, the refrigerant is a non-azeotropic mixed refrigerant.

[0084] When using non-azeotropic refrigerant mixtures, temperature glide tends to cause the refrigerant temperature to drop at the evaporator inlet side (liquid piping connection side), making frost formation more likely. In addition, frost formation generally tends to be greater at the bottom of the evaporator.

[0085] In the heat source side heat exchanger 11 of this embodiment, frost formation can be delayed when using a non-azeotropic mixed refrigerant, thereby improving the efficiency of defrosting operation.

[0086] (7-4) The heat source side heat exchanger 11 of this embodiment further comprises an upwind upper header 70, a gas side connecting pipe 72, and a liquid side connecting pipe 73. The upwind upper header 70 is located at the upper end of the upwind pipe row 55 and communicates with a plurality of flat pipes 52. The internal space of the upwind upper header 70 is divided by a first partition plate 71 into a first space SP1 which communicates with the flat pipes 52 constituting the first upwind section 55a, and a second space SP2 which communicates with the flat pipes 52 constituting the second upwind section 55b. The gas side connecting pipe 72 is connected to the first space SP1. The liquid side connecting pipe 73 is connected to the second space SP2.

[0087] With this configuration, the refrigerant inlet and outlet are positioned at the upper end of the windward pipe row 55. As a result, frost formation can be delayed, and the efficiency of defrost operation can be improved.

[0088] (7-5) In this embodiment, the heat source side heat exchanger 11 has the same number of flat pipes 52 constituting the first upstream section 55a as the same number of flat pipes 52 constituting the first downstream section 56a. The same number of flat pipes 52 constituting the second upstream section 55b as the same number of flat pipes 52 constituting the second downstream section 56b.

[0089] (7-6) In this embodiment, the heat source side heat exchanger 11 has more flattened pipes 52 constituting the first upstream section 55a than the number of flattened pipes 52 constituting the second upstream section 55b. The number of flattened pipes 52 constituting the first downstream section 56a is greater than the number of flattened pipes 52 constituting the second downstream section 56b.

[0090] In other words, in the refrigerant flow path, the number of flattened pipes 52 in the first upstream 55a and first downstream 56a on the gas refrigerant inlet / outlet side is greater than the number of flattened pipes 52 in the second upstream 55b and second downstream 56b on the liquid refrigerant inlet / outlet side. Also, the volume per unit mass is greater for gas refrigerant than for liquid refrigerant. The heat source side heat exchanger 11 of this embodiment can suppress refrigerant flow deviation by having such a configuration.

[0091] (7-7) The heat source side heat exchanger 11 of this embodiment further comprises a lower header 75. The lower header 75 is positioned at the lower ends of the upwind pipe row 55 and the downwind pipe row 56. The lower header 75 communicates with a plurality of flat pipes 52 constituting the upwind pipe row 55 and a plurality of flat pipes 52 constituting the downwind pipe row 56.

[0092] (7-8) An example of a refrigeration system of this embodiment, the air conditioning system 1, is equipped with the heat source side heat exchanger 11 of this embodiment.

[0093] (8) Modifications The above embodiments can be modified as appropriate, for example, as shown in the following modifications. Each modification may be combined with other modifications as appropriate, within the limits of what is consistent with each other.

[0094] (8-1) Modification A In the above embodiment, the heat exchange portion 50 of the heat source side heat exchanger 11 is bent in two places to form a substantially U-shape, but is not limited to this. For example, the heat exchange portion 50 may be formed in an L-shape by being bent in one place. Also, the heat exchange portion 50 may be bent in three or more places.

[0095] (8-2) Modification B In the above embodiment, the refrigeration system was described using the air conditioning system 1 as an example, but the features of the above embodiment may be applied to other types of refrigeration systems. For example, the features of the above embodiment may be applied to a hot water supply system as an example of a refrigeration system.

[0096] (8-3) Modification C In the above embodiment, the heat source unit 2 is an upward-blowing type unit, in which air is drawn in from the back and both left and right sides of the heat source unit 2, and air is blown out upward from the top of the heat source unit 2. However, the heat source unit 2 is not limited to an upward-blowing type, and may be a side-blowing type unit, for example.

[0097] (8-4) Modification D In the above embodiment, the lower header 75 is located at the lower ends of the upwind heat exchange section 50a and the downwind heat exchange section 50b, and the flat pipes 52 of the upwind pipe row 55 and the downwind pipe row 56 are connected to it. However, the lower header 75 may be composed of an upwind header to which the flat pipes 52 of the upwind pipe row 55 are connected, and a downwind header to which the flat pipes 52 of the downwind pipe row 56 are connected. The upwind header and the downwind header may be connected via piping.

[0098] (8-5) Modification E In the above embodiment, the internal space of the upwind upper header 70 is divided into a first space SP1 and a second space SP2 by a first partition plate 71. In other words, the first space SP1 and the second space SP2 are formed by dividing the same object with the first partition plate 71. However, the first space SP1 and the second space SP2 of the upwind upper header 70 may each be formed from separate objects.

[0099] (8-6) Modification F In the above embodiment, the internal space of the downwind upper header 80 is divided into a third space SP3 and a fourth space SP4 by a second partition plate 81. In other words, the third space SP3 and the fourth space SP4 are formed by dividing the same object with the second partition plate 81. However, the third space SP3 and the fourth space SP4 of the downwind upper header 80 may each be formed from separate objects.

[0100] (8-7) Modified Example G In the above embodiment, the internal space of the lower header 75 is divided into a fifth space SP5 and a sixth space SP6 by a third partition plate 76. In other words, the fifth space SP5 and the sixth space SP6 are formed by dividing the same object with the third partition plate 76. However, the fifth space SP5 and the sixth space SP6 of the lower header 75 may each be formed from separate objects.

[0101] (8-8) Modification H In the above embodiment, corrugated fins are used for the fins 54 of the heat source side heat exchanger 11, but the invention is not limited thereto. The fins 54 of the heat source side heat exchanger 11 may be, for example, insert-type fins that are inserted into a flat tube 52, as disclosed in Japanese Patent Application Publication No. 2019-132511.

[0102] While embodiments and variations of this disclosure have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of this disclosure as described in the claims.

[0103] 1 Air conditioning system (refrigeration system) 11 Heat source side heat exchanger (heat exchanger) 52 Flat pipe 54 Fin 55 Upwind pipe row 55a First upwind section 55b Second upwind section 56 Downwind pipe row 56a First downwind section 56b Second downwind section 70 Upwind upper header 71 First partition plate (partition plate) 72 Gas side connecting pipe 73 Liquid side connecting pipe 75 Lower header 80 Downwind upper header SP1 First space SP2 Second space

[0104] International Publication No. 2021 / 234953

Claims

1. An upwind pipe row (55) and a downwind pipe row (56) each composed of a plurality of flat pipes (52) extending vertically and arranged horizontally, and arranged in the direction of airflow; fins (54) to which the flat pipes are joined in each of the upwind pipe row and the downwind pipe row; a downwind upper header (80) located at the upper end of the downwind pipe row and communicating with the plurality of flat pipes constituting the downwind pipe row; the upwind pipe row is divided into a first upwind section (55a) and a second upwind section (55b), each composed of a plurality of flat pipes arranged horizontally; the downwind pipe row is divided into a first leeward section (56a) and a second leeward section (56b), each composed of a plurality of flat pipes arranged horizontally; and in the refrigerant flow path, the first upwind section, the first leeward section, the downwind upper header, the second leeward section, and the second upwind section are arranged in series. A heat exchanger (11) in which the refrigerant flows sequentially from the first upstream side to the second upstream side when used as a condenser.

2. The heat exchanger according to claim 1, wherein, when used as an evaporator, the refrigerant flows sequentially from the second upstream side to the first upstream side.

3. The heat exchanger according to claim 1 or 2, wherein the refrigerant is a non-azeotropic mixed refrigerant.

4. The heat exchanger according to any one of claims 1 to 3, further comprising: an upwind upper header (70) positioned at the upper end of the upwind pipe row and communicating with a plurality of the flat pipes; a gas-side connecting pipe (72); and a liquid-side connecting pipe (73), wherein the internal space of the upwind upper header is divided by a partition plate (71) into a first space (SP1) communicating with the flat pipes constituting the first upwind section and a second space (SP2) communicating with the flat pipes constituting the second upwind section, the gas-side connecting pipe is connected to the first space, and the liquid-side connecting pipe is connected to the second space.

5. The heat exchanger according to any one of claims 1 to 4, wherein the number of flattened tubes constituting the first upstream section is the same as the number of flattened tubes constituting the first downstream section, and the number of flattened tubes constituting the second upstream section is the same as the number of flattened tubes constituting the second downstream section.

6. The heat exchanger according to any one of claims 1 to 5, wherein the number of flattened tubes constituting the first upstream section is greater than the number of flattened tubes constituting the second upstream section, and the number of flattened tubes constituting the first downstream section is greater than the number of flattened tubes constituting the second downstream section.

7. The heat exchanger according to any one of claims 1 to 6, further comprising a lower header (75) located at the lower ends of the upwind and downwind rows of pipes, which communicates with the plurality of flat pipes constituting the upwind row and the plurality of flat pipes constituting the downwind row.

8. A refrigeration apparatus (1) comprising a heat exchanger (11) according to any one of claims 1 to 7.

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