Air conditioning device

Abstract

To provide an air conditioning device in which a flow of a refrigerant in outdoor heat exchangers is smoothed, efficient heat exchange can be performed, frost formation on the outdoor heat exchangers during heating operation is reduced, and efficient operation can be performed.SOLUTION: An air conditioning device comprises an indoor heat exchanger, a first outdoor heat exchanger, a second outdoor heat exchanger, a first pipe, a second pipe, a compressor, a four-way valve, a first expansion valve, a second expansion valve, and an ejector. The first outdoor heat exchanger comprises a first flow passage region and a second flow passage region. The second outdoor heat exchanger comprises a third flow passage region. In the second pipe, one end side comprises a first branch pipe connected to the first flow passage region, and a second branch pipe connected to the second flow passage region, and the other end side is connected to the indoor heat exchanger. The ejector comprises a first inflow / outflow port connected to the first flow passage region, a second inflow / outflow port connected to the second flow passage region, and a third inflow / outflow port connected to the third flow passage region.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an air conditioning apparatus. [Background technology]

[0002] Air conditioning devices such as air conditioners regulate indoor temperatures by absorbing and releasing heat through the condensation and evaporation of refrigerant in a refrigeration cycle. During heating operation, the refrigerant evaporates in the outdoor heat exchanger (evaporator) and condenses in the indoor heat exchanger (condenser). During cooling operation, the refrigerant condenses in the outdoor heat exchanger (condenser) and evaporates in the indoor heat exchanger (evaporator). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5328713 Summary of the Invention [Problem to be solved by the invention]

[0004] When the air conditioner described above performs heating operation, a low-temperature liquid refrigerant (liquid refrigerant) is generally supplied to the outdoor heat exchanger. However, as a result of heat exchange (evaporation) in the outdoor heat exchanger, the amount of gaseous refrigerant (gas refrigerant) increases inside the outdoor heat exchanger, resulting in a two-phase gas-liquid refrigerant. In this case, the gaseous refrigerant, which has a larger volume ratio than the liquid refrigerant, increases in the fine piping that constitutes the outdoor heat exchanger, which can obstruct the refrigerant flow and cause increased pressure loss. Furthermore, obstruction of the refrigerant flow in the fine piping can cause low-temperature liquid refrigerant to stagnate. As a result, the amount of refrigerant circulating in the air conditioner's piping decreases, and frost easily forms in the outdoor unit, requiring frequent switching to defrosting operation. This reduces heating efficiency and makes it difficult to heat the indoor air.

[0005] One example of the problem solved by the present invention is to provide an air conditioning system that allows for smoother refrigerant flow in the outdoor heat exchanger, enabling efficient heat exchange, and reducing frost formation on the outdoor heat exchanger during heating operation, enabling efficient operation. [Means for solving the problem]

[0006] An air conditioning apparatus according to one embodiment of the present invention includes an indoor heat exchanger, a first outdoor heat exchanger, a second outdoor heat exchanger, a first pipe, a second pipe, a compressor, a four-way valve, a first expansion valve, a second expansion valve, and an ejector. The indoor heat exchanger is provided in an indoor unit. The first outdoor heat exchanger is provided in an outdoor unit and includes therein a first flow path region consisting of multiple flow paths and a second flow path region consisting of a smaller number of flow paths than the first flow path region. The second outdoor heat exchanger is provided in the outdoor unit and includes therein a third flow path region consisting of multiple flow paths. The first pipe connects the second outdoor heat exchanger and the indoor heat exchanger, and a refrigerant flows through it. The second pipe has one end of a first branch pipe connected to the first flow path region and a second branch pipe connected to the second flow path region, and the other end of the second pipe is connected to the indoor heat exchanger, through which the refrigerant flows. The compressor is provided in the first pipe and has an inlet port for drawing the refrigerant and an outlet port for discharging the refrigerant. The four-way valve is provided in the first pipe and is capable of changing the direction of the refrigerant flow. A first expansion valve is provided in the second pipe. A second expansion valve is provided in the second branch pipe. The ejector is provided between the first outdoor heat exchanger and the second outdoor heat exchanger and has a first inlet / outlet that allows the refrigerant to flow in and out of the first flow path region, a second inlet / outlet that allows the refrigerant to flow in and out of the second flow path region, and a third inlet / outlet that allows the refrigerant to flow in and out of the third flow path region.

[0007] The air conditioning apparatus may also include, for example, the first expansion valve, a gas-liquid separator provided in the second pipe between the branch point of the first branch pipe and the second branch pipe, and a return pipe that returns the gaseous refrigerant separated by the gas-liquid separator to the compressor provided in the first pipe.

[0008] Furthermore, in the air conditioner, for example, the heat exchange capacity of the second outdoor heat exchanger may be larger than the heat exchange capacity of the first outdoor heat exchanger.

[0009] According to the above air conditioning system, for example, the placement of the ejector allows the refrigerant to flow more smoothly in the outdoor heat exchanger, enabling efficient heat exchange, and it is possible to provide an air conditioning system that can operate efficiently by suppressing or reducing frost formation on the outdoor heat exchanger during heating operation. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a refrigerant system diagram of an air conditioner according to an embodiment, and is also an exemplary and schematic diagram showing the flow of refrigerant during heating operation. [Figure 2] FIG. 2 is an exemplary schematic cross-sectional view showing the details of the configuration of the first outdoor heat exchanger and the second outdoor heat exchanger of the air conditioner according to the embodiment, and showing the flow of refrigerant during heating operation. [Figure 3] FIG. 3 is an exemplary schematic cross-sectional view illustrating the configuration of an ejector disposed between a first outdoor heat exchanger and a second outdoor heat exchanger of an air conditioning apparatus according to an embodiment. [Figure 4] FIG. 4 is an exemplary schematic block diagram showing a control device for an air conditioner according to an embodiment and a configuration controlled by the control device. [Figure 5] FIG. 5 is a refrigerant system diagram of an air conditioner according to an embodiment, and is also an exemplary schematic diagram showing the flow of refrigerant during cooling operation. [Figure 6]FIG. 6 is an exemplary schematic cross-sectional view showing the details of the configuration of the first outdoor heat exchanger and the second outdoor heat exchanger of the air conditioner according to the embodiment, and showing the flow of refrigerant during cooling operation. DETAILED DESCRIPTION OF THE INVENTION

[0011] Several embodiments will be described below with reference to FIGS. 1 to 6. In this specification, components according to the embodiments and descriptions of the components may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may also be described using expressions different from those in this specification.

[0012] FIG. 1 is a refrigerant system diagram of an air conditioner 10 according to an embodiment, and is also an exemplary and schematic diagram showing the flow of refrigerant during heating operation. FIG. 5 is a refrigerant system diagram of an air conditioner 10 according to an embodiment, and is also an exemplary and schematic diagram showing the flow of refrigerant during cooling operation. The air conditioner 10 is, for example, a home air conditioner. However, the air conditioner 10 is not limited to this example and may be another air conditioner, such as a commercial air conditioner.

[0013] 1 and 5, an air conditioner 10 has an outdoor unit 11, an indoor unit 12, refrigerant piping 13, and a control device 14. The outdoor unit 11 is disposed outdoors, for example. The indoor unit 12 is disposed indoors, for example.

[0014] The air conditioner 10 includes a refrigeration cycle in which an outdoor unit 11 and an indoor unit 12 are connected by refrigerant piping 13. A refrigerant flows between the outdoor unit 11 and the indoor unit 12 through the refrigerant piping 13. The outdoor unit 11 and the indoor unit 12 are also electrically connected to each other by, for example, electrical wiring.

[0015] The outdoor unit 11 includes a first outdoor heat exchanger 21A, a second outdoor heat exchanger 21B, an outdoor blower fan 22, a compressor 23, an accumulator 24, a four-way valve 25, a first expansion valve 26, a second expansion valve 27, an ejector 28, and a gas-liquid separator 29. In Fig. 1, the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B are shown in separate positions, separated from each other, for the convenience of illustrating that the ejector 28 is disposed between the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B. In this case, the heat exchange capacity of the second outdoor heat exchanger 21B is configured to be larger than the heat exchange capacity of the first outdoor heat exchanger 21A. Also shown is a state in which an outdoor blower fan 22 is disposed in each of the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B.

[0016] In this embodiment, the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B are configured with a plurality of small diameter pipes S, and are so-called microchannel type heat exchangers, as an example.

[0017] 2 and 6, the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B are configured in a stacked structure in which the second small-diameter flow path region 21AS (second flow path region) of the first outdoor heat exchanger 21A is disposed at the bottom, the first small-diameter flow path region 21AR (first flow path region) is disposed above that, and the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR, third flow path region) is disposed further above that, thereby making it possible to obtain a remarkable frost formation avoidance effect, which will be described later. Note that when the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B have a stacked structure, the outdoor blower fans 22 may be disposed individually as shown in FIG. 1, or a single outdoor blower fan 22 may be configured to blow air to both the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B.

[0018] The indoor unit 12 has an indoor heat exchanger 41 and an indoor blower fan 42.

[0019] The refrigerant pipes 13 are pipes made of metal such as copper or aluminum, and include a first pipe 51, a second pipe 52, a third pipe 53, a fourth pipe 54, and so on.

[0020] The first piping 51 connects the second outdoor heat exchanger 21B and the indoor heat exchanger 41. The compressor 23, the accumulator 24, and the four-way valve 25 are provided in the first piping 51. The first piping 51 has a first region 51a, a second region 51b, a third region 51c, and a fourth region 51d. The first region 51a is a piping region that connects the four-way valve 25 and the indoor heat exchanger 41. The second region 51b is a piping region that connects the four-way valve 25 and the accumulator 24. The third region 51c is a piping region that connects the four-way valve 25 and the second outdoor heat exchanger 21B. The fourth region 51d is a piping region that connects the four-way valve 25 and the discharge port 23b of the compressor 23.

[0021] The second piping 52 has one end including a first branch piping 52A and a second branch piping 52B connected to the first outdoor heat exchanger 21A, and the other end connected to the indoor heat exchanger 41. The first expansion valve 26, the second expansion valve 27, and the gas-liquid separator 29 are provided on the second piping 52. In addition to the first branch piping 52A and the second branch piping 52B, the second piping 52 has a fifth region 52a, a sixth region 52b, and a seventh region 52c. The fifth region 52a is a piping region that connects the outdoor heat exchanger 21 and the first expansion valve 26. The sixth region 52b is a piping region that connects the first expansion valve 26 and the first opening 29a of the gas-liquid separator 29. The seventh region 52c is a piping region that connects the second opening 29b of the gas-liquid separator 29 and the branching portion 52M that branches off the first branch pipe 52A and the second branch pipe 52B.

[0022] As described above, the second piping 52 has a first branch piping 52A and a second branch piping 52B on the first outdoor heat exchanger 21A side. The first branch piping 52A is a piping that connects the branch portion 52M and a first small-diameter flow path region 21AR (described later) of the first outdoor heat exchanger 21A. The second branch piping 52B is a piping that connects the branch portion 52M and a second small-diameter flow path region 21AS (described later) of the first outdoor heat exchanger 21A. The second expansion valve 27 is provided in the second branch piping 52B. The second branch piping 52B has an eighth region 52Ba and a ninth region 52Bb. The eighth region 52Ba is a piping region that connects the branch portion 52M and the second expansion valve 27. The ninth region 52Bb is a piping region that connects the second expansion valve 27 and the second small diameter flow path region 21AS.

[0023] Furthermore, the third piping 53 connects the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B. The ejector 28 is provided in the third piping 53. The third piping 53 has a tenth region 53a, an eleventh region 53b, and a twelfth region 53c. The tenth region 53a is a piping region that connects the first small-diameter flow path region 21AR of the first outdoor heat exchanger 21A and the first inlet / outlet 71 of the ejector 28. The eleventh region 53b is a connecting region that connects the second small-diameter flow path region 21AS of the first outdoor heat exchanger 21A and the second inlet / outlet 72 of the ejector 28. The twelfth region 53c is a connecting region that connects the third small-diameter flow path region 21BR of the second outdoor heat exchanger 21B and the third inlet / outlet 73 of the ejector 28.

[0024] The fourth pipe 54 connects the third opening 29 c of the gas-liquid separator 29 and the second region 51 b of the first pipe 51 .

[0025] As shown in Fig. 1, in heating operation, the refrigerant flows from the second outdoor heat exchanger 21B to the indoor heat exchanger 41 through the first pipe 51, flows to the first outdoor heat exchanger 21A through the second pipe 52, and further flows to the second outdoor heat exchanger 21B through the third pipe 53. Also, as shown in Fig. 5, in cooling operation, the refrigerant flows from the indoor heat exchanger 41 to the second outdoor heat exchanger 21B through the first pipe 51, and further flows to the first outdoor heat exchanger 21A through the third pipe 53. Then, the refrigerant flows to the indoor heat exchanger 41 through the second pipe 52.

[0026] The first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B of the outdoor unit 11 function as evaporators to absorb heat from the refrigerant or as condensers to release heat from the refrigerant, depending on the direction of refrigerant flow. The outdoor blower fan 22 blows air to the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B, promoting heat exchange between the refrigerant and the air in the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B. In other words, the outdoor blower fan 22 generates an airflow that exchanges heat with the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B.

[0027] 2 is an exemplary schematic cross-sectional view showing the detailed configuration of the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B of the air conditioning apparatus 10, and showing the flow of refrigerant during heating operation. As described above, the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B are stacked inside the outdoor unit 11.

[0028] The first outdoor heat exchanger 21A is configured by supporting microchannels MC, each of which is made up of a plurality of small-diameter flow paths S, between a pair of headers 21Aa and 21Ab. Each microchannel MC is, for example, a flat tube. The microchannel MC is formed by microfabricating a material with high thermal conductivity, such as aluminum, to form a plurality of small-diameter flow paths S therein. As described above, the first outdoor heat exchanger 21A is configured with a first small-diameter flow path region 21AR and a second small-diameter flow path region 21AS. In FIG. 2, for the sake of simplicity, six microchannels MC are illustrated as the first small-diameter flow path region 21AR, and one microchannel MC is illustrated as the second small-diameter flow path region 21AS. The number of microchannels MC constituting the first small-diameter flow path region 21AR and the second small-diameter flow path region 21AS can be set appropriately depending on the heat exchange capacity, but since the second small-diameter flow path region 21AS is used to form the suction flow of the ejector 28, the number of microchannels MC constituting the first small-diameter flow path region 21AR may be less than the number of microchannels MC constituting the first small-diameter flow path region 21AR, for example, one to several.

[0029] Similarly, the second outdoor heat exchanger 21B is configured by a pair of headers 21Ba, 21Bb supporting microchannels MC, each of which is made up of a plurality of small-diameter flow paths S. Each microchannel MC of the second outdoor heat exchanger 21B is also, for example, a flat tube, and is formed by microfabrication of a highly heat-conductive material such as aluminum to form a plurality of small-diameter flow paths S therein. The second outdoor heat exchanger 21B is configured by a third small-diameter flow path region 21BR. In FIG. 2, for simplicity of illustration, seven microchannels MC are shown as the third small-diameter flow path region 21BR. The number of microchannels MC constituting the second small-diameter flow path region 21BR can be appropriately set depending on the heat exchange capacity.

[0030] In the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B of this embodiment, the microchannels MC (thin-diameter flow paths S) are supported in a linear position by a pair of headers 21Aa, 21Ab, 21Ba, and 21Bb. The refrigerant flows out of the heat exchange area only in a linear flow. This makes it easier to avoid refrigerant stagnation (stagnation) at the turning points, which tends to occur in a structure in which the microchannels (thin-diameter flow paths) are turned back and forth between the headers, and also contributes to reducing pressure loss.

[0031] 2 and 6, for simplicity of illustration, the number of microchannels MC is shown as the same, but the heat exchange capacity (number of microchannels MC (thin-diameter flow paths S)) of the second outdoor heat exchanger 21B is set to be larger than the heat exchange capacity (number of microchannels MC (thin-diameter flow paths S)) of the first outdoor heat exchanger 21A. The capacity ratio of the second outdoor heat exchanger 21B to the first outdoor heat exchanger 21A is, for example, 7:3.

[0032] Normally, the entire area of the outdoor heat exchanger functions as an evaporator during heating operation. However, in the configuration of this embodiment, the first small-diameter flow path area 21AR of the first outdoor heat exchanger 21A functions as a condenser during heating operation, and only the second small-diameter flow path area 21AS functions as an evaporator.

[0033] As shown in FIGS. 2 and 6, the seventh region 52c of the second pipe 52 is connected to a branching section 52M. The branching section 52M branches the second pipe 52A into a first branching pipe 52A and a second branching pipe 52B. The first branching pipe 52A is connected to a distribution section M1. The distribution section M1 divides the flow path into a plurality of distribution pipes 52As. The distribution pipes 52As are connected to the microchannels MC (thin-diameter flow paths S) constituting the first small-diameter flow path region 21AR via a header 21Aa. During heating and cooling operations, the first small-diameter flow path region 21AR functions as a condenser. The microchannels MC (thin-diameter flow paths S) are connected to a distribution pipe 53a1 (tenth region 53a) via a header 21Ab. The distribution pipes 53a1 are gathered together at a distribution section M2 and connected to the first inlet / outlet 71 of the ejector 28 via a collecting pipe 53a2 (tenth region 53a).

[0034] On the other hand, an eighth region 52Ba of the second branch pipe 52B branched by the branch portion 52M is connected to the second expansion valve 27. The second expansion valve 27 is connected to the header 21Aa via a ninth region 52Bb of the second branch pipe 52B. The header 21Aa supports the microchannels MC (thin diameter flow paths S) constituting the second small diameter flow path region 21AS. During heating operation, the second small diameter flow path region 21AS functions as an evaporator. During cooling operation, the second small diameter flow path region 21AS functions as a condenser. The microchannels MC (thin diameter flow paths S) are connected to an eleventh region 53b of the third pipe 53 via the header 21Ab. The eleventh region 53b is connected to the second inlet / outlet 72 of the ejector 28.

[0035] A plurality of distribution pipes 53c1 (third pipes 53) are connected to the third inlet / outlet 73 of the ejector 28, and are connected to each microchannel MC (thin diameter flow paths S) constituting the third small diameter flow path region 21BR via the header 21Bb. During heating operation, the third small diameter flow path region 21BR functions as an evaporator. During cooling operation, the third small diameter flow path region 21BR functions as a condenser. The microchannels MC (thin diameter flow paths S) are connected to distribution pipes 51c1, which are the third region 51c of the first pipe 51, via the header 21Ba. Each distribution pipe 51c1 is connected to the third region 51c of the first pipe 51 that is gathered together in the distribution section M3.

[0036] 1, compressor 23 has suction port 23a and discharge port 23b. Compressor 23 draws in refrigerant through suction port 23a and discharges the compressed refrigerant through discharge port 23b. In this way, compressor 23 compresses the refrigerant in the refrigeration cycle and causes the refrigerant to circulate.

[0037] The accumulator 24 is connected to the suction port 23a of the compressor 23. The accumulator 24 separates the gaseous refrigerant from the liquid refrigerant. This allows the compressor 23 to draw the gaseous refrigerant that has passed through the accumulator 24 from the suction port 23a. The accumulator 24 can also function as the suction port of the compressor 23 by being configured integrally with the compressor 23.

[0038] The four-way valve 25 is connected to the second outdoor heat exchanger 21B, the accumulator 24 (on the side of the suction port 23a of the compressor 23), the indoor heat exchanger 41, and the discharge port 23b of the compressor 23. The four-way valve 25 switches the flow paths connected to the second outdoor heat exchanger 21B, the accumulator 24, the indoor heat exchanger 41, and the discharge port 23b of the compressor 23 between heating operation and cooling operation, thereby changing the direction in which the refrigerant flows.

[0039] 1, during heating operation, four-way valve 25 connects discharge port 23b of compressor 23 to indoor heat exchanger 41 and supplies high-temperature, high-pressure gaseous refrigerant to indoor heat exchanger 41. Also, during heating operation, four-way valve 25 connects second outdoor heat exchanger 21B to accumulator 24 and supplies low-temperature, low-pressure gaseous refrigerant to accumulator 24. As a result, the refrigerant compressed by compressor 23 flows to indoor heat exchanger 41, and further passes through first outdoor heat exchanger 21A, and finally, the refrigerant that has undergone heat exchange (evaporated) in second outdoor heat exchanger 21B flows to accumulator 24.

[0040] 5, during cooling operation, the four-way valve 25 connects the discharge port 23b of the compressor 23 to the second outdoor heat exchanger 21B and supplies high-temperature, high-pressure gaseous refrigerant to the second outdoor heat exchanger 21B. The second outdoor heat exchanger 21B flows the refrigerant to the indoor heat exchanger 41 via the ejector 28, the first outdoor heat exchanger 21A, etc. During cooling operation, the four-way valve 25 connects the indoor heat exchanger 41 to the accumulator 24 and returns the low-temperature, low-pressure gaseous refrigerant to the accumulator 24. As a result, the refrigerant compressed by the compressor 23 flows to the second outdoor heat exchanger 21B, passes through the second outdoor heat exchanger 21B and the first outdoor heat exchanger 21A, and finally, the refrigerant that has undergone heat exchange (evaporated) in the indoor heat exchanger 41 flows to the accumulator 24.

[0041] The first expansion valve 26 and the second expansion valve 27 are, for example, electromagnetic expansion valves. However, the first expansion valve 26 and the second expansion valve 27 may be other types of expansion valves. By controlling the opening degree, the first expansion valve 26 and the second expansion valve 27 adjust the amount of refrigerant passing through to determine the expansion amount of the refrigerant and adjust the decrease in the refrigerant temperature.

[0042] The ejector 28 is provided on the third pipe 53 between the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B. More specifically, the ejector 28 includes a first inlet / outlet 71, a second inlet / outlet 72, and a third inlet / outlet 73.

[0043] During heating operation, the refrigerant flowing out from the first small-diameter flow path region 21AR of the first outdoor heat exchanger 21A flows as a driving flow into the first inlet / outlet 71. Furthermore, the refrigerant flowing out from the second small-diameter flow path region 21AS of the first outdoor heat exchanger 21A flows as a suction flow into the second inlet / outlet 72. The refrigerant flowing in from the first inlet / outlet 71 and the refrigerant flowing in from the second inlet / outlet 72 are mixed, and the pressurized refrigerant is discharged toward the second outdoor heat exchanger 21B.

[0044] On the other hand, during cooling operation, the ejector 28 is used by flowing the refrigerant in the opposite direction to normal operation. In this case, the ejector 28 is used without generating the ejector effect. In this case, the second outdoor heat exchanger 21B supplies the substantially liquid refrigerant after heat exchange to the third inlet / outlet 73, and the refrigerant is supplied in this state to the first outdoor heat exchanger 21A through the first inlet / outlet 71 and the second inlet / outlet 72. In this case, the ejector solenoid valve 78 (described later) provided at the first inlet / outlet 71 may be throttled to increase the refrigerant flow rate. As a result, pressure loss in the first small-diameter flow path region 21AR of the first outdoor heat exchanger 21A during cooling operation can be reduced. In other words, the refrigerant flows more easily, improving heat exchange efficiency.

[0045] Fig. 3 is an exemplary and schematic cross-sectional view showing the structure of the ejector 28 of this embodiment. As shown in Fig. 3, the ejector 28 has a simple structure, which makes it easy to maintain and incorporate into the air conditioning apparatus 10. The structure of the ejector 28 is not limited to the example shown in Fig. 3. The ejector 28 is provided with a first inlet / outlet 71, a second inlet / outlet 72, a third inlet / outlet 73, a nozzle portion 74, a suction portion 75, a mixing portion 76, and a diffuser portion 77.

[0046] 1, the first inlet / outlet 71 is connected to the first small-diameter flow path region 21AR of the first outdoor heat exchanger 21A via the tenth region 53a of the third pipe 53. For example, during heating operation, refrigerant flows into the first inlet / outlet 71 from the first small-diameter flow path region 21AR. During cooling operation, refrigerant flows out from the first inlet / outlet 71 toward the first small-diameter flow path region 21AR.

[0047] The second inlet / outlet 72 is connected to the second small diameter flow path region 21AS of the first outdoor heat exchanger 21A via the eleventh region 53b of the third pipe 53. For example, during heating operation, the refrigerant flows into the second inlet / outlet 72 from the second small diameter flow path region 21AS side. During cooling operation, the refrigerant flows out from the second inlet / outlet 72 toward the second small diameter flow path region 21AS.

[0048] The third inlet / outlet 73 is connected to the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR) via the twelfth region 53c of the third pipe 53. For example, during heating operation, the refrigerant is supplied to the second outdoor heat exchanger 21B through the third inlet / outlet 73. During cooling operation, the refrigerant flows into the third inlet / outlet 73 from the second outdoor heat exchanger 21B.

[0049] As described above, during heating operation, the ejector 28 mixes the refrigerant (driving refrigerant) supplied to the first inlet / outlet 71 with the refrigerant (suction refrigerant) supplied to the second inlet / outlet 72, increases the pressure of the refrigerant, and discharges it from the third inlet / outlet 73. On the other hand, during cooling operation, the ejector 28 is used in a manner opposite to the normal use in which the ejector effect is obtained. In this case, the refrigerant that flows in from the third inlet / outlet 73 is discharged from the first inlet / outlet 71 and the second inlet / outlet 72 without being given the ejector effect, and is supplied to the first outdoor heat exchanger 21A side.

[0050] As shown in FIG. 3, the nozzle portion 74 is provided between the first inlet / outlet 71 and the mixing portion 76. The nozzle portion 74 is a flow path having a portion that tapers toward the mixing portion 76 and a portion that gradually expands toward the mixing portion 76. The shape of the nozzle portion 74 is not limited to this, and any structure may be used as long as it can reduce the pressure of the refrigerant that has flowed in and spray it at high speed. The nozzle portion 74 reduces the pressure of the refrigerant that has flowed into the first inlet / outlet 71, expands it, and sprays it into the mixing portion 76. Because the pressure near the outlet of the nozzle portion 74 is low, the first inlet / outlet 71 connected to the nozzle portion 74 can suck in the refrigerant.

[0051] The suction section 75 is provided between the second inlet / outlet 72 and the mixing section 76. The suction section 75 is provided around the nozzle section 74 and is a substantially cylindrical flow path having a portion tapering toward the mixing section 76. The suction section 75 decompresses and expands the refrigerant that has flowed into the second inlet / outlet 72, and sprays it into the mixing section 76. Because the pressure near the outlet of the suction section 75 is low, the second inlet / outlet 72 connected to the suction section 75 can suck in the refrigerant.

[0052] The mixing section 76 is provided between the nozzle section 74 and the suction section 75 and the diffuser section 77. In the mixing section 76, the ejector 28 mixes the refrigerant ejected from the suction section 75 with the refrigerant ejected from the nozzle section 74.

[0053] The diffuser section 77 is provided between the mixing section 76 and the third inlet / outlet 73. The diffuser section 77 is a flow path having a portion that expands toward the third inlet / outlet 73. The refrigerant mixed in the mixing section 76 is decelerated and pressurized in the diffuser section 77 and is released from the third inlet / outlet 73.

[0054] The ejector 28 has an ejector solenoid valve 78. The ejector solenoid valve 78 can open and close the first inlet / outlet 71. While FIG. 3 shows an example in which the ejector solenoid valve 78 is located outside the nozzle portion 74, the ejector solenoid valve 78 may be provided inside the nozzle portion 74 or in another location. For example, the ejector solenoid valve 78 may be a needle-shaped valve inserted into the nozzle portion 74 and its opening degree adjusted. By controlling the opening degree of the ejector solenoid valve 78, the amount of refrigerant supplied to the first inlet / outlet 71 can be adjusted, thereby controlling the ejector effect (adjusting flow rate, pressure increase, temperature, etc.). In the ejector 28, the amount of refrigerant supplied to the second inlet / outlet 72 can be adjusted by the second expansion valve 27. However, the ejector solenoid valve may be provided at or inside the second inlet / outlet 72, similar to the first inlet / outlet 71.

[0055] When the ejector 28 is used in reverse during cooling operation, the refrigerant flowing in from the third inlet / outlet 73 is discharged from the first inlet / outlet 71 and the second inlet / outlet 72 without being given the ejector effect. In other words, the ejector 28 is in an unused state.

[0056] Returning to FIG. 1, gas-liquid separator 29 is provided in second pipe 52. Gas-liquid separator 29 is, for example, a surface tension gas-liquid separator. Note that gas-liquid separator 29 may be another gas-liquid separator such as a receiver tank, as long as it can separate refrigerant into gaseous and liquid states. Gas-liquid separator 29 is provided with a first opening 28a (refrigerant inlet / outlet), a second opening 28b (refrigerant inlet / outlet), and a third opening 28c (gaseous refrigerant outlet).

[0057] During heating operation, the first opening 28a is supplied with the two-phase gas-liquid refrigerant after heat exchange in the indoor heat exchanger 41 in a low-temperature, low-pressure state expanded by the first expansion valve 26 via the sixth region 52b of the second pipe 52. The second opening 28b supplies the liquid refrigerant separated in the gas-liquid separator 29 to the first outdoor heat exchanger 21A side via the seventh region 52c. The third opening 28c supplies the gaseous refrigerant separated in the gas-liquid separator 29 to the second region 51b of the first pipe 51 via the fourth pipe 54 and returns it to the accumulator 24.

[0058] 5, during cooling operation, the first opening 28a supplies the gaseous refrigerant separated in the gas-liquid separator 29 to the indoor heat exchanger 41 via the sixth region 52b of the second pipe 52, after which the refrigerant is converted to a low-temperature, low-pressure state by the first expansion valve 26. The second opening 29b receives the gas-liquid two-phase refrigerant from the first outdoor heat exchanger 21A via the seventh region 52c. The third opening 28c supplies the gaseous refrigerant separated in the gas-liquid separator 29 to the second region 51b of the first pipe 51 via the fourth pipe 54, and returns the refrigerant to the accumulator 24.

[0059] The gas-liquid separator 29 is not essential, and the gas-liquid separator 29 and the fourth pipe 54 may be omitted. In this case, during heating operation, a two-phase gas-liquid refrigerant is supplied to the first outdoor heat exchanger 21A side (seventh region 52c).

[0060] The control device 14 controls the outdoor blower fan 22, the indoor blower fan 42, the compressor 23, the valves, and other components provided in the outdoor unit 11 and the indoor unit 12, and performs cooling, heating, dehumidifying, and other operational control. The control device 14 is composed of, for example, an outdoor control device 14a provided in the outdoor unit 11 and an indoor control device 14b provided in the indoor unit 12. The outdoor control device 14a and the indoor control device 14b are electrically connected to each other and transmit and receive control signals to cooperate to control the outdoor unit 11 and the indoor unit 12. The indoor control device 14b provided in the indoor unit 12 may be controlled by receiving signals from a remote controller operated by a user, or by receiving signals from an information terminal such as a smartphone via a communication device. The outdoor control device 14a and the indoor control device 14b may be combined into a single control device 14. In this case, the control device 14 may be provided in either the outdoor unit 11 or the indoor unit 12, but may also be provided in the indoor unit 12, for example.

[0061] The control device 14 is, for example, a computer having a control device such as a CPU (Central Processing Unit) or a microcontroller, and a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash memory. However, the control device 14 is not limited to this example.

[0062] Fig. 4 is an exemplary schematic block diagram showing the control device 14 of the air conditioner 10 of this embodiment and the configuration controlled by the control device 14. As shown in Fig. 4, the air conditioner 10 of this embodiment has an outdoor fan drive circuit 81, an indoor fan drive circuit 82, an inverter circuit 83, a four-way valve drive circuit 84, a first expansion valve drive circuit 85, a second expansion valve drive circuit 86, an ejector solenoid valve drive circuit 87, and the like.

[0063] The outdoor fan drive circuit 81 is a drive circuit for the outdoor blower fan 22. The indoor fan drive circuit 82 is a drive circuit for the indoor blower fan 42. The inverter circuit 83 inverter-controls the compressor 23 to change the frequency of the compressor 23. The inverter circuit 83 is, for example, a PAM (Pulse Amplitude Modulation) type inverter circuit. However, the inverter circuit 83 is not limited to this example.

[0064] The four-way valve drive circuit 84 is a drive circuit for the four-way valve 25. The first expansion valve drive circuit 85 is a drive circuit for the first expansion valve 26. The second expansion valve drive circuit 86 is a drive circuit for the second expansion valve 27. The ejector solenoid valve drive circuit 87 is a drive circuit for the ejector solenoid valve 78.

[0065] The control device 14 is connected to the temperature sensors T1 to T8, the temperature sensor Su, the outdoor fan drive circuit 81, the indoor fan drive circuit 82, the inverter circuit 83, the four-way valve drive circuit 84, the first expansion valve drive circuit 85, the second expansion valve drive circuit 86, and the ejector solenoid valve drive circuit 87. The control device 14 includes a temperature acquisition unit 91, an operation switching unit 92, an outdoor fan control unit 93, an indoor fan control unit 94, a compressor control unit 95, and a valve control unit 96.

[0066] The temperature acquisition unit 91 measures the temperature of each part in the refrigeration cycle using temperature sensors T1 to T8 and temperature sensor Su. For example, temperature sensor T1 detects the temperature (T1 value) of the refrigerant in the vicinity of the first small diameter flow path region 21AR between the branching portion 52M and the first small diameter flow path region 21AR of the first outdoor heat exchanger 21A. Temperature sensor T2 detects the temperature (T2 value) of the refrigerant in the first small diameter flow path region 21AR of the first outdoor heat exchanger 21A. Temperature sensor T3 detects the temperature (T3 value) of the refrigerant in the vicinity of the second small diameter flow path region 21AS between the second expansion valve 27 and the second small diameter flow path region 21AS of the first outdoor heat exchanger 21A. Temperature sensor T4 detects the temperature (T4 value) of the refrigerant in the second small diameter flow path region 21AS of the first outdoor heat exchanger 21A. The temperature sensor T5 detects the temperature (T5 value) of the refrigerant near the second outdoor heat exchanger 21B between the third inlet / outlet 73 of the ejector 28 and the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR). The temperature sensor T6 detects the temperature (T6 value) of the refrigerant in the third small-diameter flow path region 21BR of the second outdoor heat exchanger 21B. The temperature sensor T7 detects the temperature (T7 value) of the refrigerant near the indoor heat exchanger 41 between the first expansion valve 26 and the indoor heat exchanger 41. The temperature sensor T8 detects the temperature (T8 value) of the refrigerant near the indoor heat exchanger 41 between the four-way valve 25 and the indoor heat exchanger 41. The temperature sensor Su detects the temperature (Su value) of the refrigerant at the refrigerant inlet of the accumulator. The temperature sensors are not limited to the above-mentioned temperature sensors T1 to T8 and temperature sensor Su, but may be provided in various locations in the outdoor unit 11 and the indoor unit 12, and the detection results are used to control the air conditioner .

[0067] The operation switching unit 92 switches the air conditioner 10 between cooling operation, heating operation, dehumidifying operation, and other operations.

[0068] The outdoor fan control unit 93 controls the outdoor blower fan 22. For example, the outdoor fan control unit 93 controls the outdoor fan drive circuit 81 to control the rotation speed of the motor of the outdoor blower fan 22.

[0069] The indoor fan control unit 94 controls the indoor blower fan 42. For example, the indoor fan control unit 94 controls the indoor fan drive circuit 82 to control the rotation speed of the motor of the indoor blower fan 42.

[0070] The compressor control unit 95 controls the compressor 23. For example, the compressor control unit 95 controls the inverter circuit 83 to control the frequency (operating frequency) of the compressor 23 through inverter control.

[0071] The valve control unit 96 controls the four-way valve 25, the first expansion valve 26, the second expansion valve 27, and the ejector solenoid valve 78. The valve control unit 96 controls the four-way valve drive circuit 84 to drive the actuator of the four-way valve 25 and change the direction of refrigerant flow in the four-way valve 25. The valve control unit 96 controls the first expansion valve drive circuit 85 and the second expansion valve drive circuit 86 to drive the actuators of the first expansion valve 26 and the second expansion valve 27 and control the amount of refrigerant flowing (expansion amount) in the first expansion valve 26 and the second expansion valve 27. The valve control unit 96 controls the ejector solenoid valve drive circuit 87 to change the opening degree of the ejector solenoid valve 78 and adjust the flow rate of the medium.

[0072] The heating operation and cooling operation of the air conditioner 10 of this embodiment configured as described above will be described. Note that the air conditioner 10 is not limited to the heating operation and cooling operation, and can also perform other operations such as a dehumidifying operation and a sterilizing operation.

[0073] First, the heating operation will be described based on the medium flow pattern shown in Fig. 1. In the case of the heating operation, for example, if the air conditioner 10 is started and the heating operation starts simultaneously, the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 are stopped. In this case, the outdoor fan control unit 93, the indoor fan control unit 94, and the compressor control unit 95 start the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 when the heating operation starts.

[0074] During heating operation, the outdoor fan control unit 93 adjusts the rotation speed of the outdoor blower fan 22. The indoor fan control unit 94 adjusts the rotation speed of the indoor blower fan 42. For example, the indoor fan control unit 94 controls the indoor blower fan 42 between weak wind (low speed) operation and strong wind (high speed) operation in accordance with the air temperature in the room where the indoor unit 12 is installed or a signal input from a remote controller. The compressor control unit 95 adjusts the frequency of the compressor 23.

[0075] When the heating operation is started, the valve control unit 96 controls the four-way valve drive circuit 84 to change the direction of refrigerant flow in the four-way valve 25 for heating. The valve control unit 96 also controls the first expansion valve drive circuit 85 and the second expansion valve drive circuit 86 to change the open / close valve states of the first expansion valve 26 and the second expansion valve 27 for heating.

[0076] Specifically, the four-way valve 25 connects the fourth region 51d of the first pipe 51 to the first region 51a, and connects the discharge port 23b of the compressor 23 to the indoor heat exchanger 41. As a result, a high-temperature, high-pressure gaseous refrigerant is supplied to the indoor heat exchanger 41, and heat is dissipated by heat exchange in the indoor heat exchanger 41, which functions as a condenser, so that hot air can be supplied to the room.

[0077] The medium-temperature, high-pressure, almost liquid refrigerant (gas-liquid two-phase refrigerant) that flows out as a result of heat exchange in the indoor heat exchanger 41 is supplied to the first expansion valve 26 via the fifth region 52a of the second pipe 52.

[0078] During heating operation, the valve control unit 96 controls the first expansion valve 26 to a fully open state. As a result, the medium-temperature, high-pressure, two-phase gas-liquid refrigerant flowing out of the indoor heat exchanger 41 is supplied directly to the first opening 29a of the gas-liquid separator 29. The gas-liquid separator 29 separates the refrigerant into gaseous and liquid refrigerants. Most of the separated medium-temperature, high-pressure liquid refrigerant then flows through the seventh region 52c of the second pipe 52 and the branch section 52M to the first branch pipe 52A. As shown in FIG. 2, the medium-temperature, high-pressure liquid refrigerant is further distributed to multiple distribution pipes 52As by the distribution section M1 and flows into the headers 21Aa corresponding to the microchannels MC (thin-diameter flow paths S) of the first small-diameter flow path region 21AR. The medium-temperature, high-pressure liquid refrigerant supplied to the first small-diameter flow path region 21AR after passing through the header 21Aa radiates heat by exchanging heat with outside air and changes into low-temperature, high-pressure liquid refrigerant. That is, the first small diameter flow path region 21AR of the second outdoor heat exchanger 21B can function as a condenser to dissipate heat, thereby suppressing or reducing frost formation inside the outdoor unit 11 during heating operation.

[0079] The liquid refrigerant that has changed to a low temperature and high pressure in the first small diameter flow path region 21AR is supplied as a driving flow to the first inlet / outlet 71 of the ejector 28 via the header 21Ab, the distribution pipe 53a1, the distribution section M2, and the collecting pipe 53a2.

[0080] Meanwhile, the medium-temperature, high-pressure liquid refrigerant that flows from the seventh region 52c to the second branch pipe 52B via the branch portion 52M is decompressed and expanded by the second expansion valve 27 to become a low-temperature, low-pressure liquid refrigerant. The refrigerant then passes through the header 21Aa and is supplied to the second small-diameter flow path region 21AS of the first outdoor heat exchanger 21A. The low-temperature, low-pressure liquid refrigerant supplied to the second small-diameter flow path region 21AS is gasified by heat exchange with outside air. That is, the second small-diameter flow path region 21AS of the second outdoor heat exchanger 21B functions as an evaporator, and the gasified refrigerant is supplied as a suction flow to the second inlet / outlet 72 of the ejector 28 via the header 21Ab and the eleventh region 53b of the third pipe 53. In the second narrow diameter flow path region 21AS, heat is absorbed as a result of heat exchange, for example, the temperature of the microchannel MC is lowered, but heat is dissipated in the adjacent first narrow diameter flow path region 21AR, so frost formation can be suppressed or reduced.

[0081] The gas-liquid two-phase refrigerant, pressurized and temperature-adjusted by the ejector effect, flows out of the third inlet / outlet 73 of the ejector 28 and is supplied to the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR). In this case, the flow velocity of the gas-liquid two-phase refrigerant supplied to the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR) is increased by the ejector effect of the ejector 28 compared to when the ejector 28 is not present. As a result, even if the amount of gaseous refrigerant increases as a result of heat exchange with outside air in the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR), the refrigerant is easily pushed out to the third region 51c (accumulator 24 side) of the first pipe 51. In other words, refrigerant stagnation (the refrigerant becoming stagnant in the small-diameter flow paths S) is reduced inside the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR). In other words, the occupancy rate of gaseous refrigerant, which may obstruct the flow, can be reduced, thereby alleviating an increase in pressure loss. As a result, this can contribute to improving the heat exchange efficiency in the second outdoor heat exchanger 21B (third small-diameter flow path region 21BR). Furthermore, because the ejector 28 can increase the flow rate of the refrigerant, there is no need to adopt a structure such as partially narrowing the pipe diameter of the microchannel MC (small-diameter flow path S) to increase the flow rate. This can contribute to simplifying the structure of the microchannel MC (small-diameter flow path S), reducing manufacturing costs, and avoiding an increase in pressure loss due to a narrowing structure.

[0082] Furthermore, as described above, as a result of increasing the flow rate of the refrigerant by the ejector 28, an increase in pressure loss can be reduced, and heat exchange efficiency can be improved. Therefore, even if the temperature of the refrigerant supplied to the second outdoor heat exchanger 21B is increased, the heat exchange efficiency required when the refrigerant flow rate is not increased by the ejector 28 can be achieved. For example, even if a refrigerant adjusted to an outdoor temperature of -2°C, which is higher than the refrigerant supply temperature to the outdoor heat exchanger required when the refrigerant flow rate is not increased by the ejector 28, is supplied to the second outdoor heat exchanger 21B, the same heat exchange efficiency can be achieved. This also contributes to reducing the occurrence of frost.

[0083] In the second outdoor heat exchanger 21B (third small diameter flow path region 21BR), heat is absorbed as a result of heat exchange, and for example, the temperature of the microchannels MC is lowered, but heat is dissipated in the first small diameter flow path region 21AR of the adjacent first outdoor heat exchanger 21A, so frost formation can be suppressed or reduced. As described above, the stacked structure of the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B efficiently avoids frost formation.

[0084] During heating operation, the accumulator 24 (compressor 23) receives the refrigerant pressurized by the ejector 28 from the second outdoor heat exchanger 21B, and receives the high-pressure gaseous refrigerant separated by the gas-liquid separator 29 via the fourth pipe 54. As a result, the refrigerant can be returned to the compressor 23 at a higher pressure than when the ejector 28 and the gas-liquid separator 29 are not present. This means that the amount of work performed by the compressor 23 to supply high-temperature, high-pressure refrigerant to the indoor heat exchanger 41 can be reduced. This means that this contributes to energy savings during heating operation.

[0085] Next, the cooling operation will be described based on the medium flow patterns shown in Figures 5 and 6. For example, when the air conditioning apparatus 10 starts up and the cooling operation begins simultaneously, the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 are stopped. In this case, the outdoor fan control unit 93, the indoor fan control unit 94, and the compressor control unit 95 start the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 at the start of the cooling operation.

[0086] During cooling operation, the outdoor fan control unit 93 adjusts the rotation speed of the outdoor blower fan 22. The indoor fan control unit 94 adjusts the rotation speed of the indoor blower fan 42. For example, the indoor fan control unit 94 controls the indoor blower fan 42 between weak wind (low speed) operation and strong wind (high speed) operation in accordance with the temperature of the room where the indoor unit 12 is installed or a signal input from a remote controller. The compressor control unit 95 adjusts the frequency of the compressor 23.

[0087] When the cooling operation is started, the valve control unit 96 controls the four-way valve drive circuit 84 to change the direction of refrigerant flow in the four-way valve 25 for cooling. The valve control unit 96 also controls the first expansion valve drive circuit 85 and the second expansion valve drive circuit 86 to change the open / close valve states of the first expansion valve 26 and the second expansion valve 27 for cooling.

[0088] Specifically, the four-way valve 25 connects the fourth region 51d and the third region 51c of the first pipe 51, and connects the discharge port 23b of the compressor 23 and the second outdoor heat exchanger 21B. As a result, as shown in Fig. 6, high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 is supplied to the third small-diameter flow path region 21BR of the second outdoor heat exchanger 21B via the third region 51c, the distribution section M3, the distribution pipe 51c1, and the header 21Ba. The second outdoor heat exchanger 21B (third small-diameter flow path region 21BR) functions as a condenser and performs heat exchange of the refrigerant.

[0089] As a result of heat exchange in the second outdoor heat exchanger 21B, the refrigerant changes to a medium-temperature, high-pressure liquid and is supplied to the third inlet / outlet 73 of the ejector 28 via the header 21Bb and the distribution pipe 53c1. During cooling operation, the ejector 28 is used in reverse, as described above. Therefore, the refrigerant supplied to the ejector 28 is supplied to the first small-diameter flow path area AR of the first outdoor heat exchanger 21A via the first inlet / outlet 71, the collecting pipe 53a2, the distribution section M2, the distribution pipe 53a1, and the header 21Ab without any ejector effect. The first small-diameter flow path area AR functions as a condenser and performs heat exchange of the refrigerant. Similarly, the refrigerant flowing out of the second inlet / outlet 72 of the ejector 28 is supplied to the second small-diameter flow path area AS of the first outdoor heat exchanger 21A via the eleventh area 53b and the header 21Ab. The second outdoor heat exchanger 21B functions as a condenser and exchanges heat of the refrigerant.

[0090] In this case, as a result of heat exchange, refrigerant in a gas-liquid two-phase state exists inside the second outdoor heat exchanger 21B and the first outdoor heat exchanger 21A. In particular, during cooling operation, the proportion of refrigerant that has changed to liquid tends to be high in the first outdoor heat exchanger 21A, which is located downstream. Therefore, the valve control unit 96 controls the ejector solenoid valve drive circuit 87 to throttle the ejector solenoid valve 78, increasing the flow rate of the refrigerant supplied to the first small-diameter flow path region 21AR. This reduces the accumulation of liquid refrigerant in the first small-diameter flow path region 21AR (refrigerant stagnation) and improves heat exchange efficiency. Although the flow rate of the refrigerant supplied to the second small-diameter flow path region 21AS is not increased, the number of microchannels MC in the second small-diameter flow path region 21AS is smaller than the number of microchannels MC in the first small-diameter flow path region 21AR, so the impact on the overall heat exchange efficiency can be considered small.

[0091] The refrigerant supplied to the first small-diameter flow path region 21AR exchanges heat, then flows through the header 21Aa, distribution pipe 52As, distribution section M1, and first branch pipe 52A to branch section 52M. The refrigerant supplied to the second small-diameter flow path region 21AS exchanges heat, then flows through the header 21Aa and second branch pipe 52B to branch section 52M. In this case, the second expansion valve 27 provided in the second branch pipe 52B is controlled to a fully open state, and the refrigerant passes through without being decompressed or expanded.

[0092] The refrigerant that joins at branch point 52M is supplied, while still in a high-pressure state, to gas-liquid separator 29 from second opening 29b via seventh region 52c of the second pipe. The liquid refrigerant separated in gas-liquid separator 29 is decompressed and expanded by first expansion valve 26. The low-temperature, low-pressure liquid refrigerant is supplied to indoor heat exchanger 41. Then, the low-temperature, low-pressure liquid refrigerant exchanges heat with indoor air in indoor heat exchanger 41. As a result, indoor unit 12 can emit cool air into the room.

[0093] As a result of heat exchange in the indoor heat exchanger 41, the low-temperature, low-pressure gaseous refrigerant is returned to the accumulator 24 (compressor 23 side) via the four-way valve 25 and recompressed to become high-temperature, high-pressure gaseous refrigerant. Note that the gas-liquid separator 29 contains gaseous refrigerant that remains at the high pressure before being supplied to the first expansion valve 26. This high-pressure gaseous refrigerant is supplied to the second region 51b of the first pipe 51 via the fourth pipe 54 and mixed with the refrigerant returned from the indoor heat exchanger 41. In other words, the pressure of the refrigerant returned to the accumulator 24 (compressor 23 side) can be increased compared to when the refrigerant is returned only from the indoor heat exchanger 41. As a result, the workload of the compressor 23 required to supply high-temperature, high-pressure refrigerant to the second outdoor heat exchanger 21B side can be reduced. This contributes to energy savings during cooling operation.

[0094] The air conditioning apparatus 10 according to the embodiment described above includes an indoor heat exchanger 41, a first outdoor heat exchanger 21A, a second outdoor heat exchanger 21B, a first pipe 51, a second pipe 52, a compressor 23, a four-way valve 25, a first expansion valve 26, a second expansion valve 27, and an ejector 28. The indoor heat exchanger 41 is provided in the indoor unit 12. The first outdoor heat exchanger 21A is provided in the outdoor unit 11 and includes therein a first small-diameter flow path region 21AR formed of a plurality of small-diameter flow paths S and a second small-diameter flow path region AS formed of a smaller number of small-diameter flow paths S than the first small-diameter flow path region 21AR. The second outdoor heat exchanger 21B is provided in the outdoor unit 11 and includes therein a third small-diameter flow path region 21BR formed of a plurality of small-diameter flow paths S. The first pipe 51 connects the second outdoor heat exchanger 21B and the indoor heat exchanger 41, through which the refrigerant flows. The second pipe 52 has one end side of a first branch pipe 52A connected to the first small-diameter flow path region 21AR and a second branch pipe 52B connected to the second small-diameter flow path region 21AS, and the other end side of the second pipe 52 connected to the indoor heat exchanger 41, through which the refrigerant flows. The compressor 23 is provided in the first pipe 51 and has an intake port 23a for drawing in the refrigerant and an outlet port 23b for discharging the refrigerant. The four-way valve 25 is provided in the first pipe 51 and can change the direction of the refrigerant flow. The first expansion valve 26 is provided in the second pipe 52. The second expansion valve 27 is provided in the second branch pipe 52B. The ejector 28 is provided between the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B and includes a first inlet / outlet 71 that allows the refrigerant to flow into and out of the first small-diameter flow path region 21AR, a second inlet / outlet 72 that allows the refrigerant to flow into and out of the second small-diameter flow path region 21AS, and a third inlet / outlet 73 that allows the refrigerant to flow into and out of the third small-diameter flow path region 21BR. This configuration allows the refrigerant to flow more smoothly through the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B, enabling efficient heat exchange. This configuration also reduces frosting on the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B during heating operation, thereby providing an air conditioner that can operate efficiently. Furthermore, the pressure-boosting effect of the ejector 28 increases the pressure of the refrigerant returned to the compressor 23, thereby reducing the workload of the compressor 23 and contributing to energy savings.

[0095] Furthermore, the air conditioning apparatus 10 may also include, for example, a first expansion valve 26, a gas-liquid separator 29 provided in the second pipe 52 between the branch point 52M of the first branch pipe 52A and the second branch pipe 52B, and a return pipe (fourth pipe 54) that returns the gaseous refrigerant separated in the gas-liquid separator 29 to the compressor 23 provided in the first pipe 51. With this configuration, the high-pressure gaseous refrigerant separated in the gas-liquid separator 29 can be returned to the compressor 23 via the return pipe (fourth pipe 54). As a result, it is possible to reduce the workload of the compressor 23, contributing to energy savings.

[0096] Furthermore, in the air conditioning apparatus 10, for example, the heat exchange capacity of the second outdoor heat exchanger 21B may be larger than the heat exchange capacity of the first outdoor heat exchanger 21A. With this configuration, during heating operation, it is possible to effectively utilize the effect of reducing pressure loss caused by the refrigerant whose flow rate has been increased by the ejector 28.

[0097] In the above-described embodiment, the first outdoor heat exchanger 21A is a microchannel-type heat exchanger having therein a first small-diameter flow path region 21AR formed with a plurality of small-diameter flow paths S and a second small-diameter flow path region AS formed with a smaller number of small-diameter flow paths S than the first small-diameter flow path region 21AR. Similarly, the second outdoor heat exchanger 21B is a microchannel-type heat exchanger having therein a third small-diameter flow path region 21BR formed with a plurality of small-diameter flow paths S. In other embodiments, the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B may be formed with flow paths having a larger pipe diameter than the small-diameter flow paths S used in the microchannel-type heat exchanger, and the same effects as those of the present embodiment can be obtained. In this case, the first small-diameter flow path region serves as the first flow path region, and the second small-diameter flow path region serves as the second flow path region, constituting the first outdoor heat exchanger 21A. Similarly, the third small diameter flow path region constitutes the second outdoor heat exchanger 21B as the third flow path region.

[0098] In the above-described embodiment, the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B are microchannel-type heat exchangers that employ microchannels MC, but the present invention is not limited to this configuration. In other embodiments, the first outdoor heat exchanger 21A and the second outdoor heat exchanger 21B may be configured as, for example, general fin-tube heat exchangers, and the same effects as those of the present embodiment can be obtained. Similarly, the indoor heat exchanger 41 may be configured as either a microchannel-type heat exchanger or a general fin-tube heat exchanger.

[0099] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0100] 10...air conditioning device, 11...outdoor unit, 12...indoor unit, 13...refrigerant piping, 14...control device, 21A...first outdoor heat exchanger, 21B...second outdoor heat exchanger, 22...outdoor blower fan, 23...compressor, 24...accumulator, 25...four-way valve, 26...first expansion valve, 27...second expansion valve, 28...ejector, 29...gas-liquid separator, 41...indoor heat exchanger, 42...indoor blower fan, 51...first piping, 52...second piping.

Claims

1. an indoor heat exchanger provided in the indoor unit; a first outdoor heat exchanger provided in the outdoor unit, the first outdoor heat exchanger including a first flow path region formed of a plurality of flow paths and a second flow path region formed of a smaller number of flow paths than the first flow path region; a second outdoor heat exchanger provided in the outdoor unit and including a third flow path region therein, the third flow path region being configured with a plurality of flow paths; a first pipe connecting the second outdoor heat exchanger and the indoor heat exchanger and through which a refrigerant flows; a second pipe having a branch section including a first branch pipe connected to the first flow path region and a second branch pipe connected to the second flow path region at one end side, and having the other end side connected to the indoor heat exchanger, through which the refrigerant flows; a compressor provided in the first pipe, the compressor having a suction port for drawing in the refrigerant and a discharge port for discharging the refrigerant; a four-way valve provided in the first pipe and capable of changing the direction in which the refrigerant flows; a first expansion valve provided in the second pipe; a second expansion valve provided in the second branch pipe; an ejector provided between the first outdoor heat exchanger and the second outdoor heat exchanger, the ejector including a first inlet / outlet that allows the refrigerant to flow into and out of the first flow path region, a second inlet / outlet that allows the refrigerant to flow into and out of the second flow path region, and a third inlet / outlet that allows the refrigerant to flow into and out of the third flow path region; An air conditioning device comprising:

2. a gas-liquid separator provided in the second pipe between the first expansion valve and the branching portion; a return pipe provided in the first pipe for returning the gaseous refrigerant separated by the gas-liquid separator to the compressor; The air conditioning apparatus according to claim 1 .

3. 3. The air conditioner according to claim 1, wherein a heat exchange capacity of the second outdoor heat exchanger is greater than a heat exchange capacity of the first outdoor heat exchanger.

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