Air conditioning system

Abstract

To provide an air conditioning device comprising a refrigeration cycle in which heat exchangers can be downsized.SOLUTION: An air conditioning device comprises an indoor heat exchanger, an outdoor heat exchanger, a first pipe, a second pipe, a compressor, a first four-way valve, an ejector, a second four-way valve, a gas-liquid separator, a third pipe, and a fourth pipe. The first pipe connects the indoor heat exchanger and the outdoor heat exchanger, and a refrigerant flows therethrough. The second pipe connects the indoor heat exchanger and the outdoor heat exchanger, and the refrigerant flows therethrough. The third pipe connects a third opening of the gas-liquid separator and a second inflow port of the ejector. The fourth pipe connects the second pipe between a first inflow port of the ejector and the second four-way valve, and the first pipe connecting the first four-way valve and the outdoor heat exchanger, or the first pipe connecting the first four-way valve and the indoor heat exchanger.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD

[0001] Embodiments of the present invention relate to an air conditioner.

BACKGROUND ART

[0002] An air conditioner such as an air conditioning apparatus adjusts the indoor temperature by condensation and evaporation of a refrigerant in a refrigeration cycle. In heating operation, the refrigerant evaporates in an outdoor heat exchanger (evaporator) and condenses in an indoor heat exchanger (condenser). In 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

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In recent years, there has been a demand for an air conditioner that can be reduced in size and can also contribute to energy saving.

[0005] An example of the problem to be solved by the present invention is to provide an air conditioner including a refrigeration cycle that enables downsizing of a heat exchanger.

MEANS FOR SOLVING THE PROBLEMS

[0006] An air conditioning system according to one embodiment of the present invention comprises an indoor heat exchanger, an outdoor heat exchanger, a first pipe, a second pipe, a compressor, a first four-way valve, an ejector, a second four-way valve, a gas-liquid separator, a third pipe, and a fourth pipe. The indoor heat exchanger is provided in the indoor unit. The outdoor heat exchanger is provided in the outdoor unit. The first pipe connects the indoor heat exchanger and the outdoor heat exchanger, through which the refrigerant flows. The second pipe connects the outdoor heat exchanger and the indoor heat exchanger, through which the refrigerant flows. The compressor is provided in the first pipe and has an inlet for drawing in the refrigerant and an outlet for discharging the refrigerant. The first four-way valve is provided in the first pipe and can change the direction in which the refrigerant flows. The ejector is The aforementioned A first inlet is provided in the second piping, through which the refrigerant flows in from the upstream side of the second piping, The nozzle section connected to the first inlet, A second inlet from which the refrigerant flows in from a different pipe than the second pipe, A suction unit connected to the second inlet, A first inlet is provided. From the nozzle part The refrigerant supplied to and the second inlet From the suction part The refrigerant supplied is mixed and discharged from the outlet. The aforementioned It can be supplied to the downstream side of the second pipe. 。 A second four-way valve is provided in the second piping and is connected to the first inlet and outlet of the ejector, and is capable of changing the direction of flow of the refrigerant flowing out of the outlet. A gas-liquid separator is provided in the second piping and has a first opening connected to the second four-way valve, a second opening connected to the outlet, and a third opening through which gaseous refrigerant passes. The third piping connects the third opening and the second inlet. The aforementioned different piping The fourth pipe is located between the first inlet and the second four-way valve. The aforementioned The second piping is connected to the first piping that connects the first four-way valve to the outdoor heat exchanger, or to the first piping that connects the first four-way valve to the indoor heat exchanger.

[0007] Another embodiment of the present invention provides an air conditioning system comprising: an indoor heat exchanger, an outdoor heat exchanger, a first pipe, a second pipe, a compressor, a first four-way valve, an ejector, a second four-way valve, a gas-liquid separator, a third pipe, and a fourth pipe. The indoor heat exchanger is provided in the indoor unit. The outdoor heat exchanger is provided in the outdoor unit. The first pipe connects the indoor heat exchanger and the outdoor heat exchanger, through which the refrigerant flows. The second pipe connects the outdoor heat exchanger and the indoor heat exchanger, through which the refrigerant flows. The compressor is provided in the first pipe and has an intake port for drawing in the refrigerant and an outlet port for discharging the refrigerant. The first four-way valve is provided in the first pipe and can change the direction in which the refrigerant flows. The ejector is The aforementioned A first inlet is provided in the second piping, through which the refrigerant flows in from the upstream side of the second piping, The nozzle section connected to the first inlet, A second inlet from which the refrigerant flows in from a different pipe than the second pipe, A suction unit connected to the second inlet, A first inlet is provided. From the nozzle part The refrigerant supplied to and the second inlet From the suction part The refrigerant supplied is mixed and discharged from the outlet. The aforementioned It can be supplied to the downstream side of the second pipe. 。 A second four-way valve is provided in the second piping and is connected to the first inlet and outlet of the ejector, and is capable of changing the direction of flow of the refrigerant flowing out of the outlet. A gas-liquid separator is provided in the second piping and has a first opening connected to the second four-way valve, a second opening connected to the outlet, and a third opening through which gaseous refrigerant passes. The third piping connects the third opening and the second inlet. The aforementioned different piping The fourth pipe is located between the first inlet and the second four-way valve. The aforementioned The second piping is connected to the first piping that connects the first four-way valve to the outdoor heat exchanger, or to the second piping that connects the second four-way valve to the indoor heat exchanger.

[0008] Furthermore, the air conditioning system includes, for example, a refrigerant heat exchanger that performs heat exchange between the refrigerant flowing through the third pipe and the refrigerant flowing through the fourth pipe.

[0009] According to the above air conditioning system, for example, it becomes possible to improve the heat exchange efficiency in the refrigeration cycle and provide an air conditioning system that allows for miniaturization of the heat exchanger. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a refrigerant system diagram of an air conditioning system according to the first embodiment, and is also an illustrative and schematic diagram showing the flow of refrigerant during cooling operation. [Figure 2] Figure 2 is an exemplary and schematic cross-sectional view illustrating the configuration of an ejector mounted on the outdoor unit of an air conditioning system according to an embodiment. [Figure 3] Figure 3 is an exemplary and schematic block diagram showing the control device for an air conditioning system according to an embodiment and the configuration controlled by the control device. [Figure 4] Figure 4 is a refrigerant system diagram of an air conditioning system according to the first embodiment, and is also an illustrative and schematic diagram showing the flow of refrigerant during heating operation. [Figure 5] Figure 5 is a refrigerant system diagram of an air conditioning system according to the second embodiment, and is also an illustrative and schematic diagram showing the flow of refrigerant during cooling operation. [Figure 6] Figure 6 is a refrigerant system diagram of an air conditioning system according to the second embodiment, and is also an illustrative and schematic diagram showing the flow of refrigerant during heating operation. [Modes for carrying out the invention]

[0011] Several embodiments will be described below with reference to Figures 1 to 6. Note that in this specification, components and descriptions of such components may be expressed in multiple ways. The components and their descriptions are examples and are not limited by the expressions used herein. Components may also be identified by names different from those used herein. Furthermore, components may also be described by expressions different from those used herein.

[0012] First embodiment. Figure 1 is an exemplary and schematic diagram showing a refrigerant circuit diagram of an air conditioning apparatus 10 according to the first embodiment. The air conditioning apparatus 10 is, for example, a household air conditioner. Note that the air conditioning apparatus 10 is not limited to this example, and may be another air conditioning apparatus such as a commercial air conditioner.

[0013] As shown in Figure 1, the air conditioning apparatus 10 has an outdoor unit 11, an indoor unit 12, a refrigerant pipe 13, and a control device 14. The outdoor unit 11 is disposed, for example, outdoors. The indoor unit 12 is disposed, for example, indoors.

[0014] The air conditioning apparatus 10 includes a refrigeration cycle in which the outdoor unit 11 and the indoor unit 12 are connected by the refrigerant pipe 13. Refrigerant flows between the outdoor unit 11 and the indoor unit 12 through the refrigerant pipe 13. Further, the outdoor unit 11 and the indoor unit 12 are electrically connected to each other by, for example, electric wiring.

[0015] The outdoor unit 11 has an outdoor heat exchanger 21, an outdoor blower fan 22, a compressor 23, an accumulator 24, a first four-way valve 25, a second four-way valve 26, an ejector 27, a first flow rate control valve 31, a second flow rate control valve 32, a three-way valve 33 (switching valve), a gas-liquid separator 61, a refrigerant heat exchanger 62, and the like. Further, the indoor unit 12 has an indoor heat exchanger 41 and an indoor blower fan 42.

[0016] The refrigerant pipe 13 is, for example, a pipe made of metal such as copper or aluminum. The refrigerant pipe 13 includes a first pipe 51, a second pipe 52, a third pipe 53, a fourth pipe 54, and the like.

[0017] The first piping 51 connects the indoor heat exchanger 41 and the outdoor heat exchanger 21. The compressor 23, accumulator 24, and first four-way valve 25 are installed 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 the piping region connecting the first four-way valve 25 and the indoor heat exchanger 41. The second region 51b is the piping region connecting the first four-way valve 25 and the accumulator 24. The third region 51c is the piping region connecting the first four-way valve 25 and the outdoor heat exchanger 21. The fourth region 51d is the piping region connecting the first four-way valve 25 and the discharge port 23b of the compressor 23.

[0018] The second piping 52 connects the outdoor heat exchanger 21 and the indoor heat exchanger 41. The second four-way valve 26, ejector 27, and gas-liquid separator 61 are provided in the second piping 52. The second piping 52 has a fifth region 52a, a sixth region 52b, a seventh region 52c, an eighth region 52d, and a ninth region 52e. The fifth region 52a is the piping region connecting the second four-way valve 26 and the indoor heat exchanger 41. The sixth region 52b is the piping region connecting the second four-way valve 26 and the first opening 61a of the gas-liquid separator 61. The seventh region 52c is the piping region connecting the second four-way valve 26 and the outdoor heat exchanger 21. The eighth region 52d is a piping region connecting the second opening 61b of the gas-liquid separator 61 and the outlet 73 of the ejector 27. The ninth region 52e is a piping region connecting the second four-way valve 26 and the first inlet 71 of the ejector 27.

[0019] The third pipe 53 connects the gas-liquid separator 61 to the second inlet 72 of the ejector 27. The refrigerant heat exchanger 62 is provided on the third pipe 53. The third pipe 53 has a tenth region 53a and an eleventh region 53b. The tenth region 53a is a piping region connecting the third opening 61c of the gas-liquid separator 61 to the inlet side of the refrigerant heat exchanger 62. The eleventh region 53b is a piping region connecting the outlet side of the refrigerant heat exchanger 62 to the second inlet 72 of the ejector 27. The refrigerant flowing through the tenth region 53a flows into the refrigerant heat exchanger 62. It then exchanges heat with the refrigerant flowing through the fourth pipe 54 and into the refrigerant heat exchanger 62, and then flows out from the eleventh region 53b. The third pipe 53 is a pipe for supplying suction refrigerant (suction flow), which is pressurized by the driving refrigerant (driving flow) flowing in from the first inlet 71 of the ejector 27, from the second inlet 72.

[0020] The fourth piping 54 connects the second piping 52 (the ninth region 52e) between the first inlet 71 and the second four-way valve 26, and the first piping 51 (the third region 51c) connecting the first four-way valve 25 to the outdoor heat exchanger 21, or the first piping 51 (the first region 51a) connecting the first four-way valve 25 to the indoor heat exchanger 41. The first flow control valve 31, the second flow control valve 32, and the three-way valve 33 are provided in the fourth piping 54. The fourth piping 54 has a twelfth region 54a, a thirteenth region 54b, a fourteenth region 54c, and a fifteenth region 54d. The twelfth region 54a is the piping region connecting the ninth region 52e to the outlet side of the refrigerant heat exchanger 62. The 13th region 54b is a piping region connecting the inlet side of the refrigerant heat exchanger 62 to the three-way valve 33. The 14th region 54c is a piping region connecting the three-way valve 33 to the third region 51c of the first piping 51. The 15th region 54d is a piping region connecting the three-way valve 33 to the first region 51a of the first piping 51. The refrigerant flowing through the 13th region 54b flows into the refrigerant heat exchanger 62. It then exchanges heat with the refrigerant that has flowed through the third piping 53 and into the refrigerant heat exchanger 62, and flows out from the 12th region 54a into the first inlet 71 of the ejector 27. The fourth pipe 54 is a pipe that performs heat exchange (heats the refrigerant flowing through the third pipe) on the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 via the refrigerant heat exchanger 62, and supplies the heat-exchanged refrigerant to the first inlet 71 of the ejector 27.

[0021] As shown in Figure 1, during cooling operation, the refrigerant flows from the indoor heat exchanger 41 to the outdoor heat exchanger 21 through the first pipe 51, and from the outdoor heat exchanger 21 to the indoor heat exchanger 41 through the second pipe 52. Also, as shown in Figure 4, during heating operation, the refrigerant flows from the outdoor heat exchanger 21 to the indoor heat exchanger 41 through the first pipe 51, and from the indoor heat exchanger 41 to the outdoor heat exchanger 21 through the second pipe 52.

[0022] The outdoor heat exchanger 21 of the outdoor unit 11 absorbs heat from the refrigerant as an evaporator or releases heat from the refrigerant as a condenser, depending on the direction of refrigerant flow. The outdoor blower fan 22 blows air towards the outdoor heat exchanger 21, promoting heat exchange between the refrigerant and the air in the outdoor heat exchanger 21. In other words, the outdoor blower fan 22 generates an airflow that exchanges heat with the outdoor heat exchanger 21.

[0023] The compressor 23 has an inlet 23a and a discharge port 23b. The compressor 23 draws in refrigerant from the inlet 23a and discharges the compressed refrigerant from the discharge port 23b. In this way, the compressor 23 compresses the refrigerant in the refrigeration cycle and also creates a circulation of the refrigerant.

[0024] 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 in the gaseous refrigerant that has passed through the accumulator 24 from the suction port 23a. The accumulator 24 can also be integrated with the compressor 23 to serve as the suction port of the compressor 23.

[0025] The first four-way valve 25 is connected to the outdoor heat exchanger 21, the indoor heat exchanger 41, the discharge port 23b of the compressor 23, and the accumulator 24. The first four-way valve 25 switches the flow paths connected to the outdoor heat exchanger 21, the indoor heat exchanger 41, the discharge port 23b of the compressor 23, and the accumulator 24, respectively, depending on whether it is in heating operation or cooling operation, thereby changing the direction in which the refrigerant flows.

[0026] During cooling operation, the first four-way valve 25 connects the discharge port 23b of the compressor 23 to the outdoor heat exchanger 21, supplying high-temperature, high-pressure gaseous refrigerant to the outdoor heat exchanger 21. Furthermore, during cooling operation, the first four-way valve 25 connects the indoor heat exchanger 41 to the accumulator 24, returning low-temperature, low-pressure gaseous refrigerant to the accumulator 24. As a result, the refrigerant compressed by the compressor 23 flows to the outdoor heat exchanger 21, and the refrigerant that has undergone heat exchange (evaporated) in the indoor heat exchanger 41 flows to the accumulator 24.

[0027] Furthermore, during heating operation, as shown in Figure 4, the first four-way valve 25 connects the discharge port 23b of the compressor 23 to the indoor heat exchanger 41, supplying high-temperature, high-pressure gaseous refrigerant to the indoor heat exchanger 41. Also during heating operation, the first four-way valve 25 connects the outdoor heat exchanger 21 to the accumulator 24, supplying low-temperature, low-pressure gaseous refrigerant to the accumulator 24. As a result, the refrigerant compressed by the compressor 23 flows to the indoor heat exchanger 41, and the refrigerant that has undergone heat exchange (evaporated) in the outdoor heat exchanger 21 flows to the accumulator 24. Note that, as shown in Figure 4, during heating operation, the refrigerant discharged from the indoor heat exchanger 41 consists of gaseous refrigerant that returns to the accumulator 24 (compressor 23) and refrigerant that is supplied as suction refrigerant to the second inlet 72 of the ejector 27 without returning to the accumulator 24 (compressor 23). Details of ejector 27 will be described later.

[0028] The second four-way valve 26 is connected to the indoor heat exchanger 41, the first opening 61a of the gas-liquid separator 61, the outdoor heat exchanger 21, and the first inlet 71 of the ejector 27. The second four-way valve 26 switches the flow paths connected to the indoor heat exchanger 41, the first opening 61a of the gas-liquid separator 61, the outdoor heat exchanger 21, and the first inlet 71 of the ejector 27, respectively, depending on whether it is in heating or cooling operation, thereby changing the direction of refrigerant flow. The second four-way valve 26 is not limited to a general four-way valve; any valve that can change the direction of refrigerant flow may be used. For example, it may be replaced with a bridge circuit in which four check valves are connected in a ring. If a bridge circuit is used as the second four-way valve, the second four-way valve drive circuit can be omitted.

[0029] During cooling operation, as shown in Figure 1, the second four-way valve 26 connects the first opening 61a of the gas-liquid separator 61 to the indoor heat exchanger 41, supplying the liquid refrigerant separated in the gas-liquid separator 61 to the indoor heat exchanger 41. Also during cooling operation, the second four-way valve 26 connects the outdoor heat exchanger 21 to the first inlet 71 of the ejector 27, supplying the refrigerant that has undergone heat exchange (condensation) in the outdoor heat exchanger 21 as the driving refrigerant (driving flow) to the first inlet 71 of the ejector 27. In addition, the gaseous refrigerant after gas-liquid separation discharged from the third opening 61c of the gas-liquid separator 61 is supplied to the second inlet 72 of the ejector 27 via the third piping 53 as the suction refrigerant (suction flow). As described above, the refrigerant discharged from the outlet 73 of the ejector 27 is supplied to the gas-liquid separator 61 through the second opening 61b, and the low-temperature, low-pressure liquid refrigerant is continuously supplied to the indoor heat exchanger 41 through the first opening 61a.

[0030] Furthermore, during heating operation, as shown in Figure 4, the second four-way valve 26 connects the indoor heat exchanger 41 to the first inlet 71 of the ejector 27, supplying the liquid refrigerant discharged from the indoor heat exchanger 41 to the first inlet 71. A portion of the refrigerant discharged from the compressor 23 is also supplied to the first inlet 71. The second four-way valve 26 also connects the first opening 61a of the gas-liquid separator 61 to the outdoor heat exchanger 21, returning the refrigerant flowing out from the outlet 73 of the ejector 27 to the accumulator 24 via the gas-liquid separator 61 and the outdoor heat exchanger 21.

[0031] The ejector 27 is provided in the second piping 52. More specifically, the ejector 27 comprises a first inlet 71, a second inlet 72, and an outlet 73. The first inlet 71 receives refrigerant from the upstream side of the second piping 52 in the direction of refrigerant flow during cooling and heating operations. The first inlet 71 is supplied with refrigerant that has passed through the refrigerant heat exchanger 62 during cooling and heating operations. The refrigerant that passes through the refrigerant heat exchanger 62 is high-temperature, high-pressure refrigerant discharged from the compressor 23 before flowing into the outdoor heat exchanger 21 or indoor heat exchanger 41, and is the refrigerant (superheated side) after heat exchange with the refrigerant flowing through the third piping 53. The second inlet 72 receives refrigerant from the third piping 53, which is different from the second piping 52. The outlet 73 then mixes the refrigerant supplied to the first inlet 71 (driving refrigerant, driving flow) and the refrigerant supplied to the second inlet 72 (suction refrigerant, suction flow), and discharges (supplies) the pressurized refrigerant to the gas-liquid separator 61, which is located downstream of the second piping 52 in the direction of refrigerant flow during cooling and heating operations.

[0032] Figure 2 is an illustrative and schematic cross-sectional view showing the structure of the ejector 27 of this embodiment. As shown in Figure 2, the ejector 27 has a simple structure, making it easy to maintain and incorporate into the air conditioning system 10. Note that the structure of the ejector 27 is not limited to the example in Figure 2. The ejector 27 is provided with a first inlet 71, a second inlet 72, an outlet 73, a nozzle section 74, a suction section 75, a mixing section 76, and a diffuser section 77.

[0033] As shown in Figure 1, the first inlet 71 is connected to the second four-way valve 26 via the ninth region 52e of the second piping 52. For example, during cooling operation, a gaseous two-phase refrigerant flows in from the outdoor heat exchanger 21. During heating operation, a liquid refrigerant flows in from the indoor heat exchanger 41. In addition, a gaseous refrigerant is supplied from the compressor 23 via the refrigerant heat exchanger 62. In other words, a gaseous two-phase refrigerant is supplied to the first inlet 71.

[0034] The second inlet 72 is connected to the eleventh region 53b of the third piping 53. During cooling and heating operation, the gaseous refrigerant separated in the gas-liquid separator 61 flows into the second inlet 72 after being heated by heat exchange in the refrigerant heat exchanger 62. The outlet 73 discharges the pressurized gas-liquid two-phase refrigerant to the second opening 61b of the gas-liquid separator 61 via the eighth region 52d of the second piping 52.

[0035] As described above, the ejector 27 can mix the refrigerant supplied to the first inlet 71 (driving refrigerant, driving flow) with the refrigerant supplied to the second inlet 72 (suction refrigerant, suction flow), pressurize it, and discharge it from the outlet 73.

[0036] As shown in Figure 2, the nozzle section 74 is provided between the first inlet 71 and the mixing section 76. The nozzle section 74 is a flow path having a portion that tapers toward the mixing section 76 and a portion that gradually widens toward the mixing section 76. The shape of the nozzle section 74 is not limited to this; any structure is acceptable as long as it can depressurize the incoming refrigerant and inject it at high speed. The nozzle section 74 depressurizes and expands the refrigerant that flows into the first inlet 71 and ejects it into the mixing section 76. Because the pressure near the outlet of the nozzle section 74 is low, the first inlet 71 connected to the nozzle section 74 can draw in the refrigerant.

[0037] The suction section 75 is provided between the second inlet 72 and the mixing section 76. The suction section 75 is a substantially cylindrical flow path provided around the nozzle section 74 and has a portion that tapers toward the mixing section 76. The suction section 75 depressurizes and expands the refrigerant flowing into the second inlet 72 and ejects it into the mixing section 76. Because the pressure near the outlet of the suction section 75 is low, the second inlet 72 connected to the suction section 75 can draw in the refrigerant.

[0038] 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 27 mixes the refrigerant ejected from the suction section 75 with the refrigerant ejected from the nozzle section 74.

[0039] The diffuser section 77 is provided between the mixing section 76 and the outlet 73. The diffuser section 77 is a flow path having a portion that widens toward the outlet 73. The refrigerant mixed in the mixing section 76 is decelerated and pressurized in the diffuser section 77 and released from the outlet 73. In this way, the ejector 27 supplies low-temperature, low-pressure refrigerant from the outlet 73 to the gas-liquid separator 61 through the second pipe 52.

[0040] The ejector 27 has an ejector solenoid valve 78. The ejector solenoid valve 78 can open and close the first inlet 71. In Figure 2, an example is shown in which the ejector solenoid valve 78 is located outside the nozzle portion 74, but the ejector solenoid valve 78 may be located inside the nozzle portion 74 or in another part. For example, it may be a needle-shaped valve that is inserted into the nozzle portion 74 to adjust the opening degree. By controlling the opening degree of the ejector solenoid valve 78, the amount of refrigerant supplied to the first inlet 71 is adjusted. In the ejector 27, in order to adjust the amount of refrigerant supplied to the second inlet 72, an ejector solenoid valve may be provided in or inside the second inlet 72, similar to the first inlet 71, to adjust the amount of refrigerant supplied to the second inlet 72.

[0041] The first flow control valve 31 and the second flow control valve 32 are provided in the fourth piping 54. The first flow control valve 31 adjusts the amount of refrigerant flowing in during cooling operation, supplying a portion of the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 before it flows into the outdoor heat exchanger 21, via the three-way valve 33 and refrigerant heat exchanger 62 to the first inlet 71 of the ejector 27. In other words, the first flow control valve 31 adjusts its opening to balance the supply flow rate of the driving refrigerant to the ejector 27 while suppressing a decrease in the amount of high-temperature, high-pressure gaseous refrigerant supplied to the outdoor heat exchanger 21 during cooling operation, which would reduce the heat exchange efficiency. Similarly, the second flow control valve 32 adjusts the amount of refrigerant flowing in during heating operation, supplying a portion of the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 before it flows into the indoor heat exchanger 41, via the three-way valve 33 and refrigerant heat exchanger 62 to the first inlet 71 of the ejector 27. In other words, the second flow control valve 32 adjusts its opening to balance the flow rate of the driving refrigerant supplied to the ejector 27 while suppressing a decrease in the amount of high-temperature, high-pressure gaseous refrigerant supplied to the indoor heat exchanger 41 during heating operation, which would reduce the heat exchange efficiency. Note that the first flow control valve 31 and the second flow control valve 32 may be other types of control valves as long as they allow for adjustment of the refrigerant flow rate, such as expansion valves.

[0042] The three-way valve 33 is installed in the fourth piping 54. During cooling operation, the three-way valve 33 supplies the high-pressure, high-temperature gaseous refrigerant discharged from the compressor 23 to the first inlet 71 of the ejector 27 via the refrigerant heat exchanger 62 before it flows into the outdoor heat exchanger 21. As a result, the ejector 27 can be supplied with refrigerant that is not affected by the pressure loss caused by passing through the outdoor heat exchanger 21. Similarly, during heating operation, the three-way valve 33 supplies the high-pressure, high-temperature gaseous refrigerant discharged from the compressor 23 to the first inlet 71 of the ejector 27 via the refrigerant heat exchanger 62 before it flows into the indoor heat exchanger 41. As a result, the ejector 27 can be supplied with refrigerant that is not affected by the pressure loss caused by passing through the indoor heat exchanger 41. The three-way valve 33 may be replaced with other types of solenoid valves, etc., as long as the flow path can be switched.

[0043] The gas-liquid separator 61 is installed in the second piping 52. The gas-liquid separator 61 is, for example, a surface tension type gas-liquid separator. However, the gas-liquid separator 61 may be any other gas-liquid separator, such as a receiver tank, as long as it can separate the refrigerant into a gaseous state and a liquid state. The gas-liquid separator 61 is provided with a first opening 61a (liquid refrigerant outlet), a second opening 61b (gas-liquid two-phase refrigerant inlet), and a third opening 61c (gaseous refrigerant outlet).

[0044] During cooling operation, the first opening 61a supplies the liquid refrigerant separated by the gas-liquid separator 61 to the indoor heat exchanger 41 via the second four-way valve 26. During heating operation, the liquid refrigerant separated by the gas-liquid separator 61 is supplied to the outdoor heat exchanger 21 via the second four-way valve 26.

[0045] The second opening 61b receives the gas-liquid two-phase refrigerant discharged from the outlet 73 of the ejector 27 into the gas-liquid separator 61 in both cases during heating and cooling operation.

[0046] The third opening 61c supplies the gaseous refrigerant separated by the gas-liquid separator 61 to the second inlet 72 of the ejector 27 via the refrigerant heat exchanger 62, in both cases during heating and cooling operation. The gaseous refrigerant supplied from the third opening 61c is superheated by heat exchange in the refrigerant heat exchanger 62 and supplied to the second inlet 72.

[0047] The refrigerant heat exchanger 62 can utilize well-known double-tube heat exchangers, plate heat exchangers, etc., and performs heat exchange between refrigerants flowing at different temperatures in a heated region (flow path, piping) and a heated region (flow path, piping), which are independent of each other, thereby raising the temperature of the liquid refrigerant on the lower temperature side and causing it to vaporize. For example, it promotes the vaporization of the refrigerant when liquid refrigerant is mixed with the refrigerant supplied from the third opening 61c of the gas-liquid separator 61. By assisting the vaporization of the refrigerant in the refrigerant heat exchanger 62, the gas-liquid separator 61 can be miniaturized, and the efficiency of the ejector 27 can be improved by increasing the pressure of the gaseous refrigerant supplied to the second inlet 72 of the ejector 27.

[0048] As mentioned above, during cooling operation, both the liquid refrigerant flowing out from the first opening 61a of the gas-liquid separator 61 and the gaseous refrigerant flowing out from the third opening 61c are supplied to the first inlet 71 of the ejector 27. In other words, they are supplied to the ejector 27 in a gas-liquid two-phase state. Therefore, when the air conditioning system 10 is configured as a cooling-only unit, the gas-liquid separator 61 may be omitted, and the gas-liquid two-phase refrigerant discharged from the outdoor heat exchanger 21 may be supplied directly to the first inlet 71 of the ejector 27.

[0049] The control device 14 controls the outdoor fan 22, indoor fan 42, compressor 23, valves, etc., provided on the outdoor unit 11 and indoor unit 12, and performs cooling operation, heating operation, dehumidification operation, defrosting operation, and other operation control. The control device 14 is composed of, for example, an outdoor control device 14a provided on the outdoor unit 11 and an indoor control device 14b provided on the indoor unit 12. The outdoor control device 14a and the indoor control device 14b are electrically connected and send and receive control signals to each other, and cooperate to control the outdoor unit 11 and the indoor unit 12. The indoor control device 14b provided on the indoor unit 12 may be controlled by receiving signals from, for example, a remote controller operated by a user, or by receiving signals from an information terminal such as a smartphone via a communication device. Note that 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 installed on the outdoor unit 11 or on the indoor unit 12, but for example, it can be installed on the indoor unit 12.

[0050] 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 ROM (Read Only Memory), RAM (Random Access Memory), and flash memory. However, the control device 14 is not limited to this example.

[0051] Figure 3 is an exemplary and schematic block diagram showing the control device 14 of the air conditioning system 10 of this embodiment and the configuration controlled by the control device 14. As shown in Figure 3, the air conditioning system 10 of this embodiment includes an outdoor fan drive circuit 81, an indoor fan drive circuit 82, an inverter circuit 83, a first four-way valve drive circuit 84, a second four-way valve drive circuit 85, a first flow control valve drive circuit 86, a second flow control valve drive circuit 87, a three-way valve drive circuit 88, an ejector solenoid valve drive circuit 89, and the like.

[0052] The outdoor fan drive circuit 81 is the drive circuit for the outdoor blower fan 22. The indoor fan drive circuit 82 is the drive circuit for the indoor blower fan 42. The inverter circuit 83 controls the compressor 23 with an inverter and changes the frequency of the compressor 23. The inverter circuit 83 is, for example, a PAM (Pulse Amplitude Modulation) type inverter circuit. Note that the inverter circuit 83 is not limited to this example.

[0053] The first four-way valve drive circuit 84 is the drive circuit for the first four-way valve 25. The second four-way valve drive circuit 85 is the drive circuit for the second four-way valve 26. The first flow control valve drive circuit 86 is the drive circuit for the first flow control valve 31. The second flow control valve drive circuit 87 is the drive circuit for the second flow control valve 32. The three-way valve drive circuit 88 is the drive circuit for the three-way valve 33. The ejector solenoid valve drive circuit 89 is the drive circuit for the ejector solenoid valve 78.

[0054] The control device 14 is connected to temperature sensors T1 to T4 and temperature sensor Su, an outdoor fan drive circuit 81, an indoor fan drive circuit 82, an inverter circuit 83, a first four-way valve drive circuit 84, a second four-way valve drive circuit 85, a first flow control valve drive circuit 86, a second flow control valve drive circuit 87, a three-way valve drive circuit 88, and an ejector solenoid valve drive circuit 89. The control device 14 also 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.

[0055] The temperature acquisition unit 91 measures the temperature of each part of the refrigeration cycle using temperature sensors T1 to T4 and temperature sensor Su. For example, temperature sensor T1 detects the temperature of the refrigerant (T1 value) inside the indoor heat exchanger 41. Temperature sensor T2 detects the temperature of the refrigerant near the indoor heat exchanger 41 (T2 value) between the indoor heat exchanger 41 and the second four-way valve 26. Temperature sensor T3 detects the temperature of the refrigerant (T3 value) inside the outdoor heat exchanger 21. Temperature sensor T4 detects the temperature of the refrigerant near the outdoor heat exchanger 21 (T4 value) between the outdoor heat exchanger 21 and the second four-way valve 26. Temperature sensor Su detects the temperature of the refrigerant (Su value) at the refrigerant inlet of the accumulator.

[0056] The operation switching unit 92 switches between cooling operation, heating operation, dehumidification operation, defrosting operation, and other operations in the air conditioning system 10.

[0057] The outdoor fan control unit 93 controls the outdoor blower fan 22. For example, the outdoor fan control unit 93 controls the rotation speed of the motor of the outdoor blower fan 22 by controlling the outdoor fan drive circuit 81.

[0058] The indoor fan control unit 94 controls the indoor blower fan 42. For example, the indoor fan control unit 94 controls the rotation speed of the motor of the indoor blower fan 42 by controlling the indoor fan drive circuit 82.

[0059] The compressor control unit 95 controls the compressor 23. For example, the compressor control unit 95 controls the inverter circuit 83, thereby controlling the frequency (operating frequency) of the compressor 23 through inverter control.

[0060] The valve control unit 96 controls the first four-way valve 25, the second four-way valve 26, the first flow control valve 31, the second flow control valve 32, the three-way valve 33, and the ejector solenoid valve 78. The valve control unit 96 drives the actuator of the first four-way valve 25 by controlling the first four-way valve drive circuit 84, thereby changing the direction in which the refrigerant flows through the first four-way valve 25. The valve control unit 96 drives the actuator of the second four-way valve 26 by controlling the second four-way valve drive circuit 85, thereby changing the direction in which the refrigerant flows through the second four-way valve 26. The valve control unit 96 adjusts the flow rate of the medium by changing the opening degree of the first flow control valve 31, the second flow control valve 32, and the ejector solenoid valve 78 by controlling the first flow control valve drive circuit 86, the second flow control valve drive circuit 87, and the ejector solenoid valve drive circuit 89. Furthermore, the valve control unit 96 controls the three-way valve drive circuit 88 to drive the actuator of the three-way valve 33, thereby changing the direction in which the refrigerant flows through the three-way valve 33.

[0061] The cooling and heating operations of the air conditioning system 10 of this embodiment, configured as described above, will now be explained. Note that the air conditioning system 10 can perform other operations besides cooling and heating, such as dehumidification, defrosting, and sterilization. Furthermore, the cooling and heating operations of the air conditioning system 10 are not limited to the examples described below.

[0062] First, the cooling operation will be explained based on the flow pattern of the medium shown in Figure 1. For example, when the air conditioner 10 is started and the cooling operation starts at the same time, 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 cooling operation starts.

[0063] 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 low-speed and high-speed operation depending on the temperature of the room in which the indoor unit 12 is installed or a signal input from the remote controller. The compressor control unit 95 adjusts the frequency of the compressor 23.

[0064] When cooling operation is started, the valve control unit 96 controls the first four-way valve drive circuit 84, the second four-way valve drive circuit 85, and the three-way valve drive circuit 88 to change the direction of refrigerant flow in the first four-way valve 25, the second four-way valve 26, and the three-way valve 33 to cooling mode. The valve control unit 96 also controls the first flow control valve drive circuit 86 and the second flow control valve drive circuit 87 to change the opening and closing state of the first flow control valve 31 and the second flow control valve 32 to cooling mode.

[0065] Specifically, the first four-way valve 25 connects the fourth region 51d and the third region 51c of the first piping 51, and connects the discharge port 23b of the compressor 23 to the outdoor heat exchanger 21. As a result, the high-pressure, high-temperature gaseous refrigerant discharged from the compressor 23 is supplied to the outdoor heat exchanger 21. The outdoor heat exchanger 21 functions as a condenser and performs heat exchange of the refrigerant. In the case of a typical air conditioning system, in order to ensure the amount of refrigerant circulating in the outdoor heat exchanger 21, it is necessary to change the gaseous refrigerant into a liquid refrigerant in the outdoor heat exchanger 21 and supply it to the expansion valve located between the outdoor heat exchanger and the indoor heat exchanger. On the other hand, in the air conditioning system 10 of this embodiment, a gas-liquid separator 61 and an ejector 27 are located between the outdoor heat exchanger 21 and the indoor heat exchanger 41. Since the ejector 27 is a device capable of carrying two-phase gas-liquid refrigerant, there is no need to completely liquefy the refrigerant in the outdoor unit 11 (outdoor heat exchanger 21). The medium-temperature, medium-pressure two-phase gas-liquid refrigerant discharged from the outdoor heat exchanger 21 is supplied to the ejector 27 as driving refrigerant (driving flow) from the first inlet 71 via the seventh region 52c, the second four-way valve 26, and the ninth region 52e.

[0066] Furthermore, the separated gaseous refrigerant is supplied from the third opening 61c of the gas-liquid separator through the 10th region 53a, the refrigerant heat exchanger 62, and the 11th region 53b, and then heated in the refrigerant heat exchanger 62, and supplied to the ejector 27 from the second inlet 72 as suction refrigerant (suction flow). In other words, the heat exchange by the refrigerant heat exchanger 62 completely vaporizes (or promotes vaporization) the refrigerant supplied from the gas-liquid separator 61. As a result, the pressure of the suction refrigerant (suction flow) supplied to the ejector 27 is increased, which also contributes to improving the ejector effect. However, the driving refrigerant (driving flow) that flows in from the first inlet 71 after passing through the outdoor heat exchanger 21 and through the 7th region 52c, the second four-way valve 26, and the 9th region 52e experiences pressure loss as it passes through the piping, causing its pressure to drop. In other words, the pressure of the driving refrigerant (driving flow) supplied to the first inlet 71 of the ejector 27 drops, which may lead to a decrease in refrigeration capacity. Therefore, in the case of the air conditioning system 10 of this first embodiment, the first flow control valve 31 is opened to guide the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 to the fourth pipe 54 before it flows into the outdoor heat exchanger 21, and the refrigerant, which is not affected by the pressure loss caused by the outdoor heat exchanger 21, is supplied to the first inlet 71 via the fourth pipe 54. In other words, a supercooled refrigerant SC = T4 value - T3 value ≈ 0°C is supplied to the first inlet 71 as the driving refrigerant (driving flow). As a result, the pressure loss caused by the outdoor heat exchanger 21 is compensated for, and the refrigeration capacity of the ejector 27 is secured (compensated for the decrease). That is, the pressure of the driving refrigerant supplied to the first inlet 71 is increased, improving the ejector effect of the ejector 27. In other embodiments, the refrigerant heat exchanger 62 may be omitted, and the gaseous refrigerant supplied from the third opening 61c may be supplied directly to the second inlet 72, while the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 may be supplied directly to the first inlet 71. In this case, the configuration of the outdoor unit 11 can be simplified.

[0067] The gas-liquid two-phase refrigerant discharged from the outlet 73 of the ejector 27 is supplied to the gas-liquid separator 61 through the third opening 61c via the eighth region 52d, where gas-liquid separation is performed. The liquid refrigerant separated in the gas-liquid separator 61 is supplied to the indoor heat exchanger 41, which functions as an evaporator, via the sixth region 52b, the second four-way valve 26, and the fifth region 52a. As a result of heat exchange in the indoor heat exchanger 41, cool air can be discharged into the room. The refrigerant discharged from the indoor heat exchanger 41 returns to the accumulator 24 via the first region 51a, the first four-way valve 25, and the second region 51b of the first piping 51, and is sent back to the compressor 23. Note that during cooling operation, the second flow control valve 32 is closed, so the refrigerant discharged from the indoor heat exchanger 41 does not flow into the fourth piping 54 (refrigerant heat exchanger 62, ejector 27 side).

[0068] As described above, when the ejector 27 is installed on the piping of the outdoor unit 11, the refrigeration capacity is improved due to the ejector effect of the ejector 27 compared to when an expansion valve is used as in a general configuration. In other words, it is enthalpy advantageous. Therefore, if the same capacity is achieved with the outdoor heat exchanger 21, it becomes possible to miniaturize the outdoor heat exchanger 21. Furthermore, miniaturizing the outdoor heat exchanger 21 can also contribute to reducing the amount of refrigerant circulating in the refrigeration cycle.

[0069] In this way, the air conditioning system 10 of this embodiment, which controls the circulation of refrigerant during cooling operation, uses an ejector 27, eliminating the need to completely liquefy the refrigerant by supercooling it in the outdoor heat exchanger 21. In other words, it becomes possible to reduce the capacity of the outdoor heat exchanger 21. As a result, it becomes possible to miniaturize the outdoor heat exchanger 21 while maintaining the same capacity. In addition, it becomes possible to supply sufficient low-temperature, low-pressure liquid refrigerant to the indoor heat exchanger 41 via the ejector 27 and gas-liquid separator 61, and it becomes possible to miniaturize the indoor heat exchanger 41 while maintaining its cooling performance or the same capacity. Furthermore, if the outdoor heat exchanger 21 and indoor heat exchanger 41 are miniaturized in this way, the total amount of circulating refrigerant can be reduced. Also, since pressurized refrigerant can be discharged from the outlet 73 of the ejector 27, the pressure of the refrigerant in the piping can be increased, and the pressure of the refrigerant returned from the indoor heat exchanger 41 to the accumulator 24 (compressor 23) can be increased. As a result, part of the pressure boosting process performed by the compressor 23 can be supplemented by the function of the ejector 27. In this way, the total amount of circulating refrigerant is reduced and the pressure boosting process is lessened, which reduces the workload of the compressor 23 and contributes to energy saving during operation.

[0070] Next, the heating operation will be explained based on the flow pattern of the medium shown in Figure 4. For example, when the air conditioner 10 is started and the heating operation starts at the same time, 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.

[0071] 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 low-speed and high-speed operation depending on the temperature of the room in which the indoor unit 12 is installed or a signal input from the remote controller. The compressor control unit 95 adjusts the frequency of the compressor 23.

[0072] When heating operation begins, the valve control unit 96 controls the first four-way valve drive circuit 84, the second four-way valve drive circuit 85, and the three-way valve drive circuit 88 to change the direction of refrigerant flow in the first four-way valve 25, the second four-way valve 26, and the three-way valve 33 for heating. The valve control unit 96 also controls the first flow control valve drive circuit 86 and the second flow control valve drive circuit 87 to change the opening and closing state of the first flow control valve 31 and the second flow control valve 32 for heating.

[0073] Specifically, the first four-way valve 25 connects the fourth region 51d and the first region 51a of the first piping 51, and connects the discharge port 23b of the compressor 23 to the indoor heat exchanger 41. As a result, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 is supplied to the indoor heat exchanger 41. The indoor heat exchanger 41 functions as a condenser, and through heat exchange of the refrigerant, it becomes possible to discharge warm air from the indoor unit 12. However, in the case of a typical air conditioning system, in order to ensure the amount of refrigerant circulating in the indoor heat exchanger, the refrigerant is liquefied in the indoor heat exchanger and supplied to the expansion valve located between the indoor heat exchanger and the outdoor heat exchanger. For this reason, the indoor heat exchanger needs to be a subcooled heat exchanger (in other words, a supercooled heat exchanger). Because the inside of this subcooled heat exchanger contains a medium-temperature liquid refrigerant, the heat exchange efficiency may decrease. In other words, there is a risk of inducing a decrease in the temperature of the air blown out by the indoor unit. On the other hand, in the case of the air conditioning system 10 of this embodiment, since an ejector 27 capable of flowing a gas-liquid two-phase refrigerant is used, there is no need to provide a subcool heat exchanger as the indoor heat exchanger 41, and no decrease in the discharge temperature occurs. In other words, it becomes possible to improve the capacity of the indoor heat exchanger 41, and if the same capacity is achieved, it becomes possible to miniaturize the indoor heat exchanger 41.

[0074] The liquid medium-temperature, high-pressure refrigerant discharged from the indoor heat exchanger 41 is supplied to the ejector 27 as the driving refrigerant (driving flow) from the first inlet 71 via the fifth region 52a, the second four-way valve 26, and the ninth region 52e. Furthermore, the separated gaseous refrigerant is supplied to the ejector 27 as the suction refrigerant (suction flow) from the second inlet 72 via the third opening 61c of the gas-liquid separator, after being heated in the refrigerant heat exchanger 62, through the tenth region 53a, the refrigerant heat exchanger 62, and the eleventh region 53b. In other words, the refrigerant supplied from the gas-liquid separator 61 is completely vaporized (or its vaporization is accelerated) by heat exchange in the refrigerant heat exchanger 62. As a result, the pressure of the suction refrigerant (suction flow) supplied to the ejector 27 is increased, which also contributes to improving the ejector effect.

[0075] However, in the driving refrigerant (driving flow) discharged from the indoor heat exchanger 41 and flowing in as the driving refrigerant (driving flow) from the first inlet 71 via the fifth region 52a, the second four-way valve 26, and the ninth region 52e, there is a risk of pressure loss depending on the length of the piping. In other words, the pressure of the driving refrigerant (driving flow) supplied to the first inlet 71 of the ejector 27 may decrease, leading to a decrease in refrigeration capacity. Therefore, in the air conditioning system 10 of this first embodiment, the second flow control valve 32 is opened to guide the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 to the fourth piping 54 side before it flows into the indoor heat exchanger 41, and the refrigerant, which is not affected by the pressure loss due to the indoor heat exchanger 41, is supplied to the first inlet 71 via the fourth piping 54. As a result, the pressure loss due to the indoor heat exchanger 41 is compensated for, and the refrigeration capacity of the ejector 27 is secured (compensated for the decrease). In other words, the pressure of the driving refrigerant supplied to the first inlet 71 is increased to improve the ejector effect of the ejector 27. In other embodiments, the refrigerant heat exchanger 62 may be omitted, and the gaseous refrigerant supplied from the third opening 61c may be supplied directly to the second inlet 72, while the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 23 may be supplied directly to the first inlet 71. In this case, the configuration of the outdoor unit 11 can be simplified.

[0076] Furthermore, as mentioned above, the two-phase gas-liquid refrigerant discharged from the outlet 73 of the ejector 27 is supplied to the gas-liquid separator 61 through the second opening 61b in a pressurized state. The liquid refrigerant separated in the gas-liquid separator 61 is supplied to the outdoor heat exchanger 21 via the fifth region 52a, the second four-way valve 26, and the seventh region 52c. The refrigerant discharged from the outdoor heat exchanger 21 is returned to the accumulator 24, compressed again by the compressor 23, and then sent out. In this case, since the first flow control valve 31 is closed, no refrigerant from the outdoor heat exchanger 21 flows into the first inlet 71 side of the ejector 27. In this way, the two-phase gas-liquid refrigerant discharged from the outlet 73 of the ejector 27 is discharged in a pressurized state and supplied to the outdoor heat exchanger 21 via the gas-liquid separator 61. The pressure increase by the ejector 27 raises the temperature of the refrigerant compared to when it is supplied to the outdoor heat exchanger 21 via an expansion valve, as in a typical configuration. In other words, the outdoor heat exchanger 21 is supplied with refrigerant at a higher temperature than when an expansion valve is used. Therefore, it becomes possible to reduce the load on the outdoor heat exchanger 21, which functions as an evaporator during heating operation. As a result, it is possible to miniaturize the outdoor heat exchanger 21 while achieving the same capacity.

[0077] Even during heating operation, miniaturization of the outdoor heat exchanger 21 and the indoor heat exchanger 41 can reduce the total amount of circulating refrigerant. Furthermore, since pressurized refrigerant can be discharged from the outlet 73 of the ejector 27, the pressure of the refrigerant in the piping can be increased, thereby raising the pressure of the refrigerant returned from the outdoor heat exchanger 21 to the accumulator 24 (compressor 23). As a result, part of the pressurization process performed by the compressor 23 can be supplemented by the function of the ejector 27. In this way, the reduction in the total amount of circulating refrigerant and the reduction in pressurization process can reduce the workload of the compressor 23, contributing to energy savings during operation. In addition, as mentioned above, there is no need to provide a subcooling heat exchanger in the indoor heat exchanger 41, and the capacity of the indoor heat exchanger 41 can be improved without causing a decrease in the discharge temperature. As a result, the indoor heat exchanger 41 can be miniaturized to achieve the same capacity.

[0078] Furthermore, as described above, the refrigerant discharged from the outlet 73 of the ejector 27 is pressurized and its temperature rises. In other words, it becomes possible to raise the temperature of the liquid refrigerant supplied to the outdoor heat exchanger 21 after passing through the gas-liquid separator 61 above the dew point temperature. As a result, frost is less likely to form during heat exchange in the outdoor heat exchanger 21. In other words, it is possible to provide an air conditioning system 10 that does not require defrosting. In addition, the evaporation performance is improved by supplying the outdoor heat exchanger 21 with refrigerant at a temperature above the dew point temperature. As a result, it becomes possible to miniaturize the outdoor heat exchanger 21 while maintaining its performance.

[0079] Second embodiment. Figures 5 and 6 are refrigerant system diagrams of the air conditioning system according to the second embodiment. Figure 5 is an illustrative and schematic diagram showing the flow of refrigerant during cooling operation. Figure 6 is an illustrative and schematic diagram showing the flow of refrigerant during heating operation. The second embodiment differs from the first embodiment shown in Figures 1 and 4 only in the position of the 15th region 54d of the fourth pipe 54; all other configurations are the same as the first embodiment. Therefore, the same reference numerals are used for similar components, and their descriptions are omitted.

[0080] In the second embodiment, the fourth piping 54 connects the second piping (ninth region 52e) between the first inlet 71 of the ejector 27 and the second four-way valve 26, and the first piping 51 (third region 51c) connecting the first four-way valve 25 and the outdoor heat exchanger 21, or the second piping 52 (fifth region 52a) connecting the second four-way valve 26 and the indoor heat exchanger 41.

[0081] During cooling operation, the first flow control valve 31 located in the 14th region 54c of the fourth pipe 54 is opened, and the second flow control valve 32 located in the 15th region 54d is closed. As a result, the high-temperature, high-pressure refrigerant discharged from the compressor 23 is supplied to the first inlet 71 via the refrigerant heat exchanger 62. In other words, the same flow path as in the first embodiment is achieved. As a result, the same effects as described in the first embodiment can be obtained during cooling operation.

[0082] On the other hand, during heating operation, the first flow control valve 31 located on the 14th region 54c of the fourth pipe 54 is closed, and the second flow control valve 32 located on the 15th region 54d is opened. As a result, the medium-temperature, high-pressure refrigerant discharged from the indoor heat exchanger 41 is supplied to the first inlet 71 via the refrigerant heat exchanger 62. In this case, although the refrigerant passing through the indoor heat exchanger 41 is subject to pressure loss as described above, it is supplied to the first inlet 71 via the refrigerant heat exchanger 62, and almost the same effect as described in the first embodiment can be obtained.

[0083] The air conditioning system 10 according to the embodiment described above comprises an indoor heat exchanger 41, an outdoor heat exchanger 21, a first pipe 51, a second pipe 52, a compressor 23, a first four-way valve 25, an ejector 27, a second four-way valve 26, a gas-liquid separator 61, a third pipe 53, and a fourth pipe 54. The indoor heat exchanger 41 is installed in the indoor unit 12. The outdoor heat exchanger 21 is installed in the outdoor unit 11. The first pipe 51 connects the indoor heat exchanger 41 and the outdoor heat exchanger 21, through which the refrigerant flows. The second pipe 52 connects the outdoor heat exchanger 21 and the indoor heat exchanger 41, through which the refrigerant flows. The compressor 23 is installed in the first pipe 51 and has an intake port 23a for drawing in refrigerant and an outlet port 23b for discharging refrigerant. The first four-way valve 25 is installed in the first piping 51 and can change the direction in which the refrigerant flows. The ejector 27 is installed in the second piping 52 and has a first inlet 71 into which refrigerant flows in from the upstream side of the second piping 52, and a second inlet 72 into which refrigerant flows in from a different piping than the second piping 52. The ejector 27 can mix the refrigerant supplied to the first inlet 71 with the refrigerant supplied to the second inlet 72 and supply the pressurized mixture to the downstream side of the second piping 52 from the outlet 73. The second four-way valve 26 is installed in the second piping 52 and is connected to the first inlet 71 and outlet 73 of the ejector 27, and can change the direction in which the refrigerant flows out from the outlet 73. The gas-liquid separator 61 is provided in the second piping 52 and has a first opening 61a connected to the second four-way valve 56, a second opening 61b connected to the outlet 73, and a third opening 61c through which the gaseous refrigerant passes. The third piping 53 connects the third opening 61c to the second inlet 72. The fourth piping 54 connects the second piping 52 between the first inlet 71 and the second four-way valve 26, and the first piping 51 connecting the first four-way valve 25 to the outdoor heat exchanger 21 or the first piping 51 connecting the first four-way valve 25 to the indoor heat exchanger 41. With this configuration, for example, it becomes possible to supplement part of the work of the compressor 23 with the ejector 27, which can contribute to energy saving. Furthermore, the heat exchange efficiency in the refrigeration cycle can be improved, enabling miniaturization of the outdoor heat exchanger 21 and the indoor heat exchanger 41, and contributing to a reduction in the total amount of circulating refrigerant.

[0084] An air conditioning system 10 according to another embodiment of the present invention comprises an indoor heat exchanger 41, an outdoor heat exchanger 21, a first pipe 51, a second pipe 52, a compressor 23, a first four-way valve 25, an ejector 27, a second four-way valve 26, a gas-liquid separator 61, a third pipe 53, and a fourth pipe 54. The indoor heat exchanger 41 is provided in the indoor unit 12. The outdoor heat exchanger 21 is provided in the outdoor unit 11. The first pipe 51 connects the indoor heat exchanger 41 and the outdoor heat exchanger 21, through which the refrigerant flows. The second pipe 52 connects the outdoor heat exchanger 21 and the indoor heat exchanger 41, through which the refrigerant flows. The compressor 23 is provided in the first pipe 51 and has an inlet 23a for drawing in refrigerant and an outlet 23b for discharging refrigerant. The first four-way valve 25 is installed in the first piping 51 and can change the direction in which the refrigerant flows. The ejector 27 is installed in the second piping 52 and has a first inlet 71 into which refrigerant flows in from the upstream side of the second piping 52, and a second inlet 72 into which refrigerant flows in from a different piping than the second piping 52. The ejector 27 can mix the refrigerant supplied to the first inlet 71 with the refrigerant supplied to the second inlet 72 and supply the pressurized mixture to the downstream side of the second piping 52 from the outlet 73. The second four-way valve 26 is installed in the second piping 52 and is connected to the first inlet 71 and outlet 73 of the ejector 27, and can change the direction in which the refrigerant flows out from the outlet 73. The gas-liquid separator 61 is provided in the second piping 52 and has a first opening 61a connected to the second four-way valve 56, a second opening 61b connected to the outlet 73, and a third opening 61c through which the gaseous refrigerant passes. The third piping 53 connects the third opening 61c to the second inlet 72. The fourth piping 54 connects the second piping 52 between the first inlet 71 and the second four-way valve 26, and the first piping 51 connecting the first four-way valve 25 to the outdoor heat exchanger 21, or the second piping 52 connecting the second four-way valve 26 to the indoor heat exchanger 41. With this configuration, for example, it becomes possible to supplement part of the work of the compressor 23 with the ejector 27, which can contribute to energy saving. Furthermore, the heat exchange efficiency in the refrigeration cycle can be improved, enabling miniaturization of the outdoor heat exchanger 21 and the indoor heat exchanger 41, and contributing to a reduction in the total amount of circulating refrigerant.

[0085] Furthermore, the air conditioning unit 10 may also include a refrigerant heat exchanger 62 that performs heat exchange between the refrigerant flowing through the third pipe 53 and the refrigerant flowing through the fourth pipe 54. This configuration allows for the complete or accelerated vaporization of the refrigerant heading towards the second inlet 72 of the ejector 27. As a result, even if the extraction of gaseous refrigerant from the gas-liquid separator 61 is insufficient, a sufficient supply of gaseous refrigerant can be provided to the second inlet 72. In this case, the capacity of the gas-liquid separator 61 can be reduced, contributing to miniaturization. It also becomes possible to increase the pressure of the gaseous refrigerant heading towards the second inlet 72 of the ejector 27, contributing to an improved ejector effect.

[0086] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0087] 10...Air conditioning unit, 11...Outdoor unit, 12...Indoor unit, 13...Refrigerant piping, 14...Control device, 21...Outdoor heat exchanger, 23...Compressor, 24...Accumulator, 25...First four-way valve, 26...Second four-way valve, 27...Ejector, 31...First flow control valve, 32...Second flow control valve, 33...Three-way valve (switching valve), 41...Indoor heat exchanger, 51...First piping, 52...Second piping, 53...Third piping, 54...Fourth piping, 61...Gas-liquid separator, 62...Refrigerant heat exchanger, 71...First inlet, 72...Second inlet, 73...Outlet.

Claims

1. The indoor heat exchanger installed in the indoor unit, The outdoor heat exchanger installed on the outdoor unit, A first pipe connects the indoor heat exchanger and the outdoor heat exchanger, through which the refrigerant flows, A second pipe connects the outdoor heat exchanger and the indoor heat exchanger, through which the refrigerant flows, A compressor provided in the first piping, having an inlet for drawing in the refrigerant and an outlet for discharging the refrigerant, A first four-way valve is provided in the first piping and capable of changing the direction in which the refrigerant flows, An ejector is provided in the second piping and includes a first inlet into which the refrigerant flows in from the upstream side of the second piping, a nozzle connected to the first inlet, a second inlet into which the refrigerant flows in from a different pipe than the second piping, and a suction section connected to the second inlet, and is capable of mixing the refrigerant supplied from the first inlet to the nozzle section and the refrigerant supplied from the second inlet to the suction section and supplying the mixture from the outlet to the downstream side of the second piping. A second four-way valve is provided in the second piping, connected to the first inlet and outlet of the ejector, and capable of changing the direction of flow of the refrigerant flowing out from the outlet, A gas-liquid separator provided in the second piping, having a first opening connected to the second four-way valve, a second opening connected to the outlet, and a third opening through which gaseous refrigerant passes, The third pipe, which is a different pipe, connects the third opening and the second inlet, A second pipe between the first inlet and the second four-way valve, a fourth pipe connecting the first pipe connecting the first four-way valve and the outdoor heat exchanger, or the first pipe connecting the first four-way valve and the indoor heat exchanger, An air conditioning system equipped with the following features.

2. The indoor heat exchanger installed in the indoor unit, The outdoor heat exchanger installed on the outdoor unit, A first pipe connects the indoor heat exchanger and the outdoor heat exchanger, through which the refrigerant flows, A second pipe connects the outdoor heat exchanger and the indoor heat exchanger, through which the refrigerant flows, A compressor provided in the first piping, having an inlet for drawing in the refrigerant and an outlet for discharging the refrigerant, A first four-way valve is provided in the first piping and capable of changing the direction in which the refrigerant flows, An ejector is provided in the second piping and includes a first inlet into which the refrigerant flows in from the upstream side of the second piping, a nozzle connected to the first inlet, a second inlet into which the refrigerant flows in from a different pipe than the second piping, and a suction section connected to the second inlet, and is capable of mixing the refrigerant supplied from the first inlet to the nozzle section and the refrigerant supplied from the second inlet to the suction section and supplying the mixture from the outlet to the downstream side of the second piping. A second four-way valve is provided in the second piping, connected to the first inlet and outlet of the ejector, and capable of changing the direction of flow of the refrigerant flowing out from the outlet, A gas-liquid separator provided in the second piping, having a first opening connected to the second four-way valve, a second opening connected to the outlet, and a third opening through which gaseous refrigerant passes, The third pipe, which is a different pipe, connects the third opening and the second inlet, A second pipe between the first inlet and the second four-way valve, a fourth pipe connecting the first pipe connecting the first four-way valve and the outdoor heat exchanger, or the second pipe connecting the second four-way valve and the indoor heat exchanger, An air conditioning system equipped with the following features.

3. The air conditioning system according to claim 1 or claim 2, further comprising a refrigerant heat exchanger that performs heat exchange between the refrigerant flowing through the third pipe and the refrigerant flowing through the fourth pipe.

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