JPWO2018122943A1 - Air conditioner - Google Patents

Abstract

An air conditioner capable of simultaneous cooling and heating operation in which each of the indoor units can selectively perform the cooling operation or the heating operation, wherein the relay unit is connected to the outdoor unit via the first refrigerant pipe and the second refrigerant pipe. A first branch unit connected to the indoor unit and having an open / close valve selectively connecting one of the refrigerant inlet and outlet of the indoor heat exchanger in the indoor unit to the second refrigerant piping via the first refrigerant piping or the gas-liquid separator; When the other of the refrigerant inlet / outlet of the indoor heat exchanger in this case is the refrigerant inlet, it is connected to the gas-liquid separator via the first expansion device, and the other of the refrigerant inlet / outlet of the indoor heat exchanger in the indoor unit is the refrigerant outlet (1) A second branch portion having a check valve connected to the outlet side of the first expansion device, and an initial opening degree at which a pressure difference before and after the first expansion device becomes equal to or greater than a reference value when starting the compressor; Set as the opening of And that the controller, in which with a.

Description

  The present invention relates to an air conditioner that suppresses noise generated by a check valve.

  Generally, in the air conditioning apparatus, conditioned air is generated by circulating a refrigerant that transfers heat to a pipe provided between the outdoor unit and the indoor unit. Further, in an air conditioner capable of performing simultaneous cooling and heating operation in which cooling operation and heating operation are mixed, a relay unit for distributing the refrigerant to each indoor unit is installed between the outdoor unit and the indoor unit. (See, for example, Patent Document 1).

  In the air conditioner of Patent Document 1, check valves are provided in parallel in the relay, and the flow of refrigerant during cooling operation and heating operation is controlled by the check valves.

Patent No. 4785508

  In the air conditioner of Patent Document 1, when the pressure difference before and after the check valve is small, such as at the start of the compressor, the valve body of the check valve vibrates and the sound of the valve body colliding with the valve seat continues. Problem that occurs.

  The present invention has been made to solve the problems as described above, and it is an object of the present invention to provide an air conditioner capable of suppressing a sound generated by a check valve.

  An air conditioner according to the present invention includes an outdoor unit having a compressor, a flow path switching device, and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger and an indoor expansion device, the outdoor unit, and The relay unit is provided between the indoor unit and the relay unit for controlling the flow of the refrigerant flowing into the indoor unit according to the operation state of the indoor unit, and each of the indoor units selects the cooling operation or the heating operation. Air conditioner capable of simultaneous operation of heating and cooling, wherein the relay is connected to the outdoor unit via a first refrigerant pipe and a second refrigerant pipe, and the indoor heat in the indoor unit is A first branch portion having an on-off valve selectively connecting one of the refrigerant inlet and outlet of the exchanger to the second refrigerant pipe via the first refrigerant pipe or the gas-liquid separator; Is connected to the gas-liquid separator via the first expansion device when the other of the refrigerant inlet and outlet of the indoor heat exchanger in the chamber is the refrigerant inlet, and the other of the refrigerant inlet and outlet of the indoor heat exchanger in the indoor unit is The pressure difference before and after the first expansion device becomes equal to or greater than a reference value at the time of starting the second branch portion having a check valve connected to the outlet side of the first expansion device when it becomes a refrigerant outlet And a controller configured to set the initial opening degree as the opening degree of the first throttling device.

  According to the air conditioner according to the present invention, when the compressor is started, the opening degree of the first expansion device is set to the initial opening degree at which the pressure difference before and after the first expansion device is equal to or greater than the reference value. By securing the pressure difference before and after the stop valve, the vibration of the valve body of the check valve can be suppressed, and the sound generated by the check valve can be suppressed.

It is a figure showing the composition of the air harmony device concerning an embodiment of the invention. It is a figure which shows the flow of the refrigerant | coolant in the refrigerant circuit at the time of the cooling only operation of the air conditioning apparatus which concerns on embodiment of this invention. It is a figure which shows the flow of the refrigerant | coolant in the refrigerant circuit at the time of all heating operation of the air conditioning apparatus which concerns on embodiment of this invention. It is a figure which shows the flow of the refrigerant | coolant in the refrigerant circuit at the time of the cooling main operation of the air conditioning apparatus which concerns on embodiment of this invention. It is a figure which shows the flow of the refrigerant | coolant in the refrigerant circuit at the time of heating main operation of the air conditioning apparatus which concerns on embodiment of this invention. It is a functional block diagram of the air harmony device concerning an embodiment of the invention. It is a first flowchart showing a process of determining the opening degree of the indoor expansion device of the indoor unit according to the embodiment of the present invention. It is a 2nd flowchart which shows the process which determines the opening degree of the indoor expansion device of the indoor unit which concerns on embodiment of this invention. It is a flowchart of control which suppresses the vibration noise of the 1st non-return valve and 2nd non-return valve which the outdoor controller and relay controller which concern on embodiment of this invention perform.

  Hereinafter, embodiments of the present invention will be described based on the drawings. The present invention is not limited by the embodiments described below. Moreover, in the following drawings, the relationship of the magnitude | size of each structural member may differ from an actual thing.

Embodiment.
FIG. 1 is a diagram showing the configuration of an air conditioning apparatus 100 according to an embodiment of the present invention.
As shown in FIG. 1, the air conditioner 100 according to the present embodiment includes an outdoor unit 51, a plurality of indoor units 52a and 52b, and a relay 53 between the outdoor unit 51 and the indoor units 52a and 52b, Equipped with The outdoor unit 51 and the relay unit 53 are connected by a first gas pipe 103 and a first liquid pipe 104 through which the refrigerant flows. The relay 53 and the indoor unit 52a are connected by the second liquid pipe 105a and the second gas pipe 106a, and the relay 53 and the indoor unit 52b are connected with the second liquid pipe 105b and the second gas pipe 106b. Connected by

  The first gas pipe 103 is an example of the “first refrigerant pipe” in the present invention, and the first liquid pipe 104 is an example of the “second refrigerant pipe” in the present invention.

  The air conditioning apparatus 100 is, for example, an air conditioning apparatus 100 in which each indoor unit 52a, 52b can independently perform a cooling operation or a heating operation. The air conditioning apparatus 100 is one of the indoor units 52a and 52b that performs the cooling operation, the indoor unit 52a and 52b performs the heating operation, and the indoor unit 52a and 52b. Can perform the cooling operation, and the other can perform the heating operation, and can perform the simultaneous cooling and heating operation in which the cooling operation and the heating operation are mixed.

[Outdoor unit 51]
The outdoor unit 51 includes a compressor 1, a flow path switching device 3, an outdoor heat exchanger 2, an accumulator 4, and a refrigerant flow control unit 54. The compressor 1 sucks, compresses and discharges the refrigerant. As the compressor 1, it is possible to use, for example, an inverter circuit or the like that can change the amount of refrigerant to be delivered per unit time by capacity control. Further, a first pressure sensor 31 for detecting the pressure Pd is provided on the discharge side of the compressor 1, and a second pressure sensor 32 for detecting the pressure Ps is provided on the suction side of the compressor 1. The pressures Pd and Ps detected by the first pressure sensor 31 and the second pressure sensor 32 are sent to the outdoor controller 201. The outdoor controller 201 functions as a controller that controls the entire air conditioning apparatus 100.

  The outdoor heat exchanger 2 circulates the refrigerant inside and exchanges heat between the refrigerant and the air outside the room. During the heating operation, the outdoor heat exchanger 2 functions as an evaporator, and evaporates and evaporates the refrigerant. Also, in the cooling operation, the refrigerant functions as a condenser to condense and liquefy the refrigerant. The flow path switching device 3 switches the flow of a refrigerant such as a four-way valve, for example, and the operation content such as a cooling operation or a heating operation is changed by switching the flow path switching device 3. The accumulator 4 stores the surplus of the liquid refrigerant. The refrigerant flow control unit 54 allows the flow direction of the refrigerant to one direction only.

[Refrigerant flow control unit 54]
The refrigerant flow control unit 54 includes connection pipes 130, 131, 132, 133 connecting the connection portions a, b, c, d, and check valves 7a, 7b, 7c, which allow the flow of the refrigerant in one direction. 7d. The refrigerant flow control unit 54 is a part of the components of the outdoor unit 51. The connecting pipe 130 connects the connecting portion c and the connecting portion a, the connecting pipe 131 connects the connecting portion d and the connecting portion b, and the connecting pipe 132 connects the connecting portion c and the connecting portion d. The connection pipe 133 connects the connection portion a and the connection portion b. The first gas piping 103 connected to the relay 53 and the high pressure piping 102 connected to the compressor 1 are connected by the connection piping 132, and the low pressure piping 101 connected to the compressor 1 by the connection piping 133, The first liquid pipe 104 connected to the relay 53 is connected.

  The check valve 7a is disposed in the connection pipe 132 and allows the flow of the refrigerant from the connection portion c to the connection portion d. The check valve 7 b is disposed in the connection pipe 133 and allows the flow of the refrigerant from the connection portion a to the connection portion b. The check valve 7c is disposed in the connection pipe 131 and allows the flow of the refrigerant from the connection portion d to the connection portion b. The check valve 7d is disposed in the connection pipe 130, and allows the flow of the refrigerant from the connection portion c to the connection portion a.

[Indoor units 52a, 52b]
The indoor units 52a and 52b include indoor heat exchangers 5a and 5b and indoor expansion devices 6a and 6b. Each component of indoor unit 52a, 52b is controlled by indoor controller 202a, 202b. The indoor heat exchangers 5a and 5b cause the refrigerant that has passed through the relay 53 to flow inside, and exchange heat between the refrigerant and the air to be air-conditioned. The indoor heat exchangers 5a and 5b function as a condenser during heating operation to condense and liquefy the refrigerant. The second liquid pipes 105a and 105b connected to the indoor expansion devices 6a and 6b are connected to the relay fork 53b via the relay fork 55a and the relay second liquid pipe 113, respectively. There is. The indoor heat exchangers 5a and 5b function as an evaporator during the cooling operation to evaporate and evaporate the refrigerant.

  The indoor expansion devices 6a and 6b function as a pressure reducing valve or an expansion valve to decompress and expand the refrigerant. The indoor expansion devices 6a and 6b only need to be capable of adjusting the pressure of the refrigerant according to the air conditioning load, and can use, for example, a flow control means such as an electronic expansion valve. The first temperature sensors 33a and 33b and the second temperature sensors 34a and 34b are disposed in the indoor units 52a and 52b. The first temperature sensors 33a and 33b and the second temperature sensors 34a and 34b detect the temperature of the refrigerant flowing into and out of the indoor heat exchangers 5a and 5b, and send detected signals to the indoor controllers 202a and 202b. It is.

[Repeater 53]
The relay 53 includes a gas-liquid separator 8, a first branch 20, a first expansion device 11, a second expansion device 12, a first heat exchanger 13, a second heat exchanger 14, and a second branch 21. And controls the flow of the refrigerant flowing into the indoor units 52a and 52b in accordance with the operating state of the indoor units 52a and 52b. The relay unit 53 controls the flow of refrigerant between the outdoor unit 51 and the indoor units 52a and 52b, so that the indoor units 52a and 52b can perform simultaneous cooling and heating operation.

  Each component of the relay 53 is controlled by the relay controller 203, and each component includes the bypass pipe 110, the relay first liquid pipe 111, the relay gas pipe 112, and the relay second liquid pipe 113. Connected by The relay unit 53 is connected to the outdoor unit 51 by the first gas pipe 103 and the first liquid pipe 104. The relay 53 is connected to each of the indoor units 52a and 52b by the second liquid pipes 105a and 105b and the second gas pipes 106a and 106b.

  The gas-liquid separator 8 separates the refrigerant into a liquid refrigerant and a gas refrigerant, and is connected to the first liquid pipe 104, the relay first liquid pipe 111, and the relay gas pipe 112. The first liquid pipe 104 connects the outdoor unit 51 and the gas-liquid separator 8, the relay first liquid pipe 111 connects the gas-liquid separator 8 and the relay fork 55b, and the relay gas pipe Reference numeral 112 connects the gas-liquid separator 8 and each of the first on-off valves 9 a and 9 b of the first branch unit 20.

  The first branch portion 20 selectively connects one of the refrigerant inlets and outlets of the indoor heat exchangers 5a and 5b in the indoor units 52a and 52b to the first liquid pipe 104 via the first gas pipe 103 or the gas-liquid separator 8. The first on-off valve 9a, 9b and the second on-off valve 10a, 10b. The second branch 21 is connected to the gas-liquid separator 8 via the first expansion device 11 when the other of the refrigerant inlets and outlets of the indoor heat exchangers 5a and 5b in the indoor units 52a and 52b is the refrigerant inlet, The first check valve 15a, 15b connected to the outlet side of the first expansion device 11 when the other of the refrigerant inlet / outlet of the indoor heat exchangers 5a, 5b in the indoor units 52a, 52b is the refrigerant outlet, and the second non-return valve It is comprised by valve 16a, 16b.

  Second gas pipes 106a and 106b are branched and connected to the first on-off valves 9a and 9b and the second on-off valves 10a and 10b, respectively. The first on-off valves 9 a and 9 b are configured to shut off the gas refrigerant flowing from the relay gas pipe 112 to the indoor units 52 a and 52 b by opening and closing or to pass the refrigerant in a direction flowing out of the relay 53. The first on-off valves 9a and 9b are opened when the indoor units 52a and 52b connected via the second gas pipes 106a and 106b are performing a heating operation. Further, the second on-off valves 10a and 10b are for blocking the gas refrigerant flowing into the relay unit 53 from the second gas pipes 106a and 106b of the indoor units 52a and 52b or for causing the gas refrigerant to flow in the relay unit 53 direction. is there. The second on-off valves 10a and 10b are opened when the indoor units 52a and 52b connected via the second gas pipes 106a and 106b are performing the cooling operation.

The first check valve 15a allows the flow of the refrigerant from the connection portion g to the connection portion f. The first check valve 15 b allows the flow of the refrigerant in the direction from the connection portion g to the connection portion h.
The second check valve 16a allows the flow of the refrigerant from the connection portion f to the connection portion e. The second check valve 16b allows the flow of the refrigerant from the connection h to the connection e.

  The first heat exchanger 13 causes the liquid refrigerant separated in the gas-liquid separator 8 and the liquid refrigerant flowing through the second heat exchanger 14 to flow and exchange heat. The first expansion device 11 decompresses the liquid refrigerant that has passed through the first heat exchanger 13 and causes the liquid refrigerant to flow into the second heat exchanger 14. The second heat exchanger 14 causes the refrigerant decompressed in the first expansion device 11 to flow and the liquid refrigerant decompressed in the second expansion device 12 to exchange heat.

  The first heat exchanger 13, the first expansion device 11, and the second heat exchanger 14 are interposed between the gas-liquid separator 8 and the relay fork portion 55 a, and are connected by the relay first liquid pipe 111. It is done. The bypass pipe 110 connects the relay fork portion 55 a and the first gas pipe 103 via the second expansion device 12, the second heat exchanger 14, and the first heat exchanger 13, and thus the liquid refrigerant Is returned to the outdoor unit 51. In addition, as the first expansion device 11 and the second expansion device 12, for example, a flow control unit capable of precise control of the flow rate by changing the opening degree such as an electronic expansion valve may be used.

  The third pressure sensor 35 is disposed between the first heat exchanger 13 and the first expansion device 11, and detects a pressure P35 therebetween. The fourth pressure sensor 36 is disposed between the first expansion device 11 and the second heat exchanger 14 and detects a pressure P36 therebetween. The pressures P35 and P36 detected by the third pressure sensor 35 and the fourth pressure sensor 36 are sent to the relay controller 203, respectively.

  Next, the operation of the air conditioning apparatus 100 according to the present embodiment will be described. The air conditioning apparatus 100 can perform all-cooling operation, all-heating operation, and simultaneous heating and cooling operation. Among them, simultaneous operation of heating and cooling can be performed in two operation modes of heating main operation when the heating load is high and cooling main operation when the cooling load is high. Therefore, the air conditioning apparatus 100 can operate in four different operation modes.

FIG. 2 is a diagram showing the flow of the refrigerant in the refrigerant circuit during the cooling only operation of the air conditioning apparatus 100 according to the embodiment of the present invention. In addition, the arrow of FIG. 2 has shown the direction of the refrigerant | coolant, and the same may be said of FIGS. 3-5 mentioned later.
First, the operation in the all-cooling operation where both of the indoor units 52a and 52b perform the cooling operation will be described. During the cooling only operation, the indoor units 52a and 52b both perform the cooling operation, the first on-off valves 9a and 9b of the relay unit 53 are closed, and the second on-off valves 10a and 10b are open.

  As shown in FIG. 2, the refrigerant is compressed in the compressor 1 and discharged as a high-temperature, high-pressure gas refrigerant, and flows from the flow path switching device 3 into the outdoor heat exchanger 2. The refrigerant flowing into the outdoor heat exchanger 2 condenses in the outdoor heat exchanger 2 by heat exchange with the outdoor air, condenses and liquefies, flows out, and flows into the refrigerant flow control unit 54 from the low pressure pipe 101. The refrigerant flowing into the refrigerant flow control unit 54 passes from the refrigerant flow control unit 54 through the check valve 7b of the connection pipe 133 without flowing into the connection pipe 130 by the check valve 7d in the refrigerant flow control unit 54. It flows out and flows into the relay unit 53 from the outdoor unit 51.

  The refrigerant flowing into the relay unit 53 is separated into liquid refrigerant and gas refrigerant in the gas-liquid separator 8. In the cooling only operation, all of the refrigerant is liquid refrigerant, and all of the refrigerant flows into the relay first liquid pipe 111, so it does not flow into the relay gas pipe 112. The refrigerant flowing into the relay first liquid pipe 111 is increased in the degree of supercooling in the first heat exchanger 13 while flowing through the relay first liquid pipe 111, and is reduced to an intermediate pressure in the first expansion device 11. In the second heat exchanger 14, the degree of subcooling is further increased to reach the relay fork 55a.

  The refrigerant that has reached the relay fork portion 55a is divided at the relay fork portion 55a, a part of which flows into the bypass pipe 110, and the remaining part passes through the first check valve 15a, 15b and flows out of the relay 53 . The refrigerant flowing into the bypass pipe 110 is depressurized to a low pressure in the second expansion device 12, flows through the second heat exchanger 14 and the first heat exchanger 13 in this order, evaporates by heat exchange, and becomes a gas refrigerant. 1 merge with the gas pipe 103; At this time, the refrigerant in the bypass pipe 110 increases the degree of supercooling of the refrigerant flowing through the relay first liquid pipe 111 by heat exchange.

  The refrigerant split at the relay fork part 55b and flowing out from the relay 53 flows through the second liquid pipes 105a and 105b and flows into the indoor units 52a and 52b. The refrigerant flowing into the indoor units 52a and 52b is reduced in pressure by the indoor expansion devices 6a and 6b of the indoor units 52a and 52b, and then exchanges heat with the air in the air-conditioned space in the indoor heat exchangers 5a and 5b. While cooling the air of the air conditioning target space, it evaporates and gasifies. Thereby, cooling of the air conditioning target space is realized.

  The gasified refrigerant passes through the indoor heat exchangers 5a and 5b, flows through the second gas pipes 106a and 106b, flows out from the indoor units 52a and 52b, flows into the relay unit 53 again, and is opened. It passes through the on-off valves 10a and 10b. The refrigerant that has passed through the second on-off valves 10 a and 10 b joins the refrigerant flowing through the bypass pipe 110 in the first gas pipe 103, flows out of the relay 53, and flows into the outdoor unit 51.

  The refrigerant flowing into the outdoor unit 51 passes through the check valve 7 a disposed in the connection pipe 132 of the refrigerant flow control unit 54 in the outdoor unit 51, and is drawn into the compressor 1 via the accumulator 4. Thus, the refrigerant circuit is circulated by the refrigerant.

FIG. 3 is a diagram showing the flow of the refrigerant in the refrigerant circuit during the heating only operation of the air conditioning apparatus 100 according to the embodiment of the present invention.
Next, the operation at the time of all heating operation which performs heating operation among indoor units 52a and 52b is explained. During the heating only operation, the indoor units 52a and 52b both perform the heating operation, the first on-off valves 9a and 9b of the relay unit 53 are opened, and the second on-off valves 10a and 10b are closed. As shown in FIG. 3, the refrigerant is compressed in the compressor 1 and discharged as a high temperature, high pressure gas refrigerant, and flows from the flow path switching device 3 into the refrigerant flow control unit 54 to reach the connection portion d . The refrigerant that has reached the connection portion d can not flow through the connection pipe 132 from the connection portion d by the check valve 7a, flows into the connection pipe 131, passes through the check valve 7c, and passes through the connection portion b. Evacuate from 51.

  The refrigerant flowing out of the outdoor unit 51 flows through the first liquid pipe 104 and flows into the relay 53. The refrigerant flowing into the relay unit 53 is separated into the gas refrigerant and the liquid refrigerant in the gas-liquid separator 8. In the heating only operation, all the refrigerant is the gas refrigerant, and all the refrigerant flows into the relay gas pipe 112, so the refrigerant does not flow into the relay first liquid pipe 111. The refrigerant flowing into the relay gas pipe 112 reaches the first on-off valves 9a and 9b, passes through the first on-off valves 9a and 9b in the open state, and flows out from the relay 53.

  The refrigerant flowing out of the relay 53 flows into the indoor units 52a and 52b, and exchanges heat with the air of the air conditioning target space in the indoor heat exchangers 5a and 5b, and condenses while radiating to the air of the air conditioning target space Liquefy. Thereby, heating of the air conditioning target space is performed. The liquefied refrigerant passes through the indoor heat exchangers 5a and 5b, is decompressed in the indoor expansion devices 6a and 6b, becomes a liquid refrigerant at an intermediate pressure, and flows out from the indoor units 52a and 52b.

  The refrigerant that has flowed out of the indoor units 52a and 52b flows through the second liquid pipes 105a and 105b and flows into the relay 53, passes through the second check valves 16a and 16b, and the relay fork portion 55a, and then flows from the bypass pipe 110 1 merges into the gas pipe 103 and flows out from the relay 53; The refrigerant flowing out of the relay 53 flows through the first gas pipe 103 and reaches the connection portion c of the refrigerant flow control unit 54. The refrigerant that has reached the connection portion c can not flow through the connection pipe 132 having high pressure in the connection portion c, and passes through the check valve 7 d of the connection pipe 130 and flows through the low pressure pipe 101. The refrigerant flowing through the low pressure pipe 101 is evaporated by heat exchange with the outdoor air while passing through the outdoor heat exchanger 2 from the low pressure pipe 101, and is sucked into the compressor 1 via the flow path switching device 3 and the accumulator 4 Ru. Thus, the refrigerant circuit is circulated by the refrigerant.

FIG. 4 is a diagram showing the flow of the refrigerant in the refrigerant circuit during the cooling main operation of the air conditioning apparatus 100 according to the embodiment of the present invention.
Next, a simultaneous cooling and heating operation in which the indoor unit 52a performs a heating operation and the indoor unit 52b performs a cooling operation will be described. During simultaneous heating and cooling operation, the first on-off valve 9a and the second on-off valve 10b of the relay device 53 are in the open state, and the first on-off valve 9b and the second on-off valve 10a are in the closed state.

  First, the flow of the refrigerant in the case of performing the cooling main operation where the cooling load is higher than the heating load will be described. As shown in FIG. 4, the refrigerant is compressed by the compressor 1 and is condensed and liquefied by heat exchange in the outdoor heat exchanger 2 and flows out as a gas-liquid two-phase refrigerant. The amount of refrigerant condensed and liquefied in the outdoor heat exchanger 2, that is, the ratio of the gas refrigerant and the liquid refrigerant is determined according to the ratio of the cooling load and the heating load. The refrigerant flowing out of the outdoor heat exchanger 2 flows through the low pressure pipe 101, passes through the check valve 7b of the refrigerant flow control unit 54, flows out from the outdoor unit 51, flows through the first liquid pipe 104, and relays It flows into 53.

  The refrigerant that has flowed into the relay unit 53 is separated into liquid refrigerant and gas refrigerant in the gas-liquid separator 8, and the liquid refrigerant flows into the relay first liquid pipe 111 and the gas refrigerant flows into the relay gas pipe 112. Do.

  The liquid refrigerant that has flowed into the relay first liquid pipe 111 is increased in the degree of supercooling while passing through the first heat exchanger 13, the first expansion device 11, and the second heat exchanger 14, and the relay three forks Reach 55a. Part of the refrigerant that has reached the relay fork portion 55a flows through the bypass pipe 110, and the remaining part of the refrigerant is branched so as to flow out of the relay 53 through the first check valves 15a and 15b. The refrigerant that has flowed into the bypass pipe 110 from the relay fork portion 55a absorbs heat by heat exchange while passing through the second expansion device 12, the second heat exchanger 14, and the first heat exchanger 13, and evaporates. It vaporizes and reaches the first gas pipe 103.

  On the other hand, the gas refrigerant that has flowed into the relay gas pipe 112 reaches the first on-off valves 9a and 9b, passes through the first on-off valve 9a in the open state, and flows out of the relay 53, and the second gas pipe 106a Flows into the indoor unit 52a. The refrigerant passes through the indoor heat exchanger 5a of the indoor unit 52a and condenses and liquefies while radiating heat to the air of the air-conditioned space by heat exchange. Thereby, heating of the air conditioning target space is performed. The refrigerant that has passed through the indoor heat exchanger 5a is decompressed by the indoor expansion device 6a and becomes an intermediate pressure liquid refrigerant, and flows out from the indoor unit 52a, passes through the second liquid pipe 105a, and reaches the relay fork 55b Do.

  In the relay fork portion 55b, the refrigerant flowing through the second liquid pipe 105a connected to the indoor unit 52a and the refrigerant passing through the first expansion device 11 merge and flow through the second heat exchanger. Part of the refrigerant that has flowed through the second heat exchanger 14 flows through the bypass pipe 110, and the remaining flows through the first check valve 15b so as to flow out of the relay device 53. The refrigerant flowing out of the relay device 53 is decompressed from the second liquid pipe 105b by the indoor expansion device 6b in the indoor unit 52b, and flows into the indoor heat exchanger 5b. The refrigerant that has flowed into the indoor heat exchanger 5b is vaporized in the indoor heat exchanger 5b by heat exchange with the air in the space to be air-conditioned to gasify and flow out as a gas refrigerant. Thereby, the air conditioning target space is cooled. The refrigerant that has passed through the indoor heat exchanger 5b passes through the second open / close valve 10b in the open state.

  The refrigerant that has passed through the second on-off valve 10 b merges with the refrigerant that has also flowed through the bypass pipe 110 that reaches the first gas pipe 103, and flows through the first gas pipe 103 and flows out of the relay 53. Flow into The refrigerant flowing into the outdoor unit 51 passes through the check valve 7 a provided in the connection pipe 132 in the refrigerant flow control unit 54 of the outdoor unit 51, and the flow path switching device 3 passes through the accumulator 4 to the compressor 1. Inhaled. Thus, the refrigerant circuit is circulated by the refrigerant.

FIG. 5 is a view showing the flow of the refrigerant in the refrigerant circuit at the heating main operation of the air conditioning apparatus 100 according to the embodiment of the present invention.
Next, the flow of the refrigerant in the case of performing the heating main operation in which the heating load is higher than the cooling load will be described. As shown in FIG. 5, the refrigerant is compressed and discharged by the compressor 1, passes through the flow path switching device 3, and reaches the connection portion d of the refrigerant flow control unit 54. The refrigerant that has reached the connection portion d passes through the check valve 7 c provided in the connection pipe 131, flows out of the outdoor unit 51 through the first liquid pipe 104, and flows into the relay unit 53.

  The refrigerant flowing into the relay 53 flows from the gas-liquid separator 8 into the relay gas pipe 112. At this time, since the heating main operation is performed, the liquid refrigerant separated in the gas-liquid separator 8 does not exist, and the refrigerant does not flow to the relay first liquid pipe 111. The refrigerant having flowed into the relay gas pipe 112 reaches the first on-off valves 9a and 9b, passes through the first open / close valve 9a, flows out of the relay 53, and passes through the second gas pipe 106a. It flows into the unit 52a. The refrigerant that has flowed into the indoor unit 52a passes through the indoor heat exchanger 5a of the indoor unit 52a and condenses and liquefies while radiating heat to the air of the air-conditioned space by heat exchange. Thereby, heating of the air conditioning target space is performed. The refrigerant that has passed through the indoor heat exchanger 5a is decompressed by the indoor expansion device 6a to be an intermediate pressure liquid refrigerant, flows from the indoor unit 52a into the second liquid pipe 105a, and flows into the relay 53.

  The refrigerant having flowed into the relay device 53 flows through the second check valve 16a, the relay second liquid pipe 113, and the second heat exchanger 14, and reaches the relay fork portion 55a. Part of the refrigerant that has reached the relay fork portion 55 a flows through the bypass pipe 110, and the remaining part flows so as to flow out of the relay 53 through the first check valve 15 b. The refrigerant flowing out of the relay device 53 is decompressed from the second liquid pipe 105b by the indoor expansion device 6b in the indoor unit 52b, and flows into the indoor heat exchanger 5b. The refrigerant that has flowed into the indoor heat exchanger 5b is vaporized in the indoor heat exchanger 5b by heat exchange with the air in the space to be air-conditioned to gasify and flow out as a gas refrigerant. Thereby, the air conditioning target space is cooled. The refrigerant that has passed through the indoor heat exchanger 5b passes through the second open / close valve 10b in the open state.

  The refrigerant that has passed through the second on-off valve 10 b merges with the refrigerant that has also flowed through the bypass pipe 110 that reaches the first gas pipe 103, and flows through the first gas pipe 103 and flows out of the relay 53. Flow into In the refrigerant flow control unit 54 of the outdoor unit 51, the refrigerant flowing into the outdoor unit 51 passes through the check valve 7d disposed in the connection pipe 130 and flows into the outdoor heat exchanger 2 from the low pressure pipe 101. The refrigerant flowing into the outdoor heat exchanger 2 is vaporized by the heat exchange in the outdoor heat exchanger 2 to be gasified, and is sucked into the compressor 1 via the flow path switching device 3 and the accumulator 4. Thus, the refrigerant circuit is circulated by the refrigerant.

  During the heating only operation, the first expansion device 11 of the relay unit 53 is opened in order to flow the hot gas into the relay unit 53 to improve the rising when the compressor 1 is started. In addition, during simultaneous cooling and heating operation, the first throttle is set so that the pressure difference ΔP between pressure P35 and pressure P36, which is the pressure difference around the first expansion device 11 in the relay device 53, becomes a preset value. The opening LEV 11 of the device 11 is adjusted.

  However, when the opening degree LEV11 of the first expansion device 11 increases, the pressure difference ΔP before and after the first expansion device 11 decreases. The pressure of the connection parts f and h is close to the pressure of the third pressure sensor 35, and the connection parts e and g are close to the pressure of the fourth pressure sensor 36. Therefore, when the opening degree LEV11 of the first expansion device 11 increases, the pressure difference ΔPa before and after the first check valves 15a and 15b and the second check valves 16a and 16b decreases.

  Further, when the pressure difference ΔPa before and after the first check valve 15a, 15b and the second check valve 16a, 16b becomes equal to or more than the reference value B, the valve body is lifted, and the refrigerant flows. In this case, the valve is lowered by its own weight. As the value of the reference value B, a manufacturer's guarantee value or a specific value obtained in advance in a test is used. When the pressure difference ΔPa approaches the reference value B, the valve body is repeatedly lifted and lowered, and the sound of the valve body colliding with the valve seat is continuously generated. Therefore, in the present embodiment, vibration noise of the first check valves 15a and 15b and the second check valves 16a and 16b is suppressed.

FIG. 6 is a functional block diagram of the air conditioning apparatus 100 according to the embodiment of the present invention.
As shown in FIG. 6, the outdoor controller 201 is electrically connected to each of the indoor controllers 202 a and 202 b and the relay controller 203. The outdoor controller 201 has a function as a main controller that controls the control of the air conditioner 100. The outdoor controller 201 also has a timer (not shown) for measuring time.

  The outdoor controller 201 determines an instruction for each of the indoor controllers 202a and 202b and the relay controller 203 based on the information notified from the indoor controllers 202a and 202b and the relay controller 203. And notify. The outdoor controller 201 acquires the pressures Pd and Ps detected by the first pressure sensor 31 and the second pressure sensor 32 provided in the outdoor unit 51, and the operating frequency Fa of the compressor 1 and the capacity of the outdoor heat exchanger 2 Control AKa.

  The indoor controllers 202a, 202b detect the temperatures T33a, T33b and T34a, T34b by the first temperature sensors 33a, 33b and the second temperature sensors 34a, 34b, and notify the outdoor controller 201 of the temperatures. Further, based on the temperatures T33a, T33b and T34a, T34b, the degrees of opening LEV6a, LEV6b of the indoor expansion devices 6a, 6b are calculated and notified to the indoor expansion devices 6a, 6b.

  The relay controller 203 notifies the first expansion device 11 and the second expansion device 12 of the openings LEV 11 and LEV 12 according to the instruction of the outdoor controller 201, and the first on-off valves 9a and 9b and the second It instructs to open and close the on-off valves 10a and 10b. Further, P 35 and P 36 detected by the third pressure sensor 35 and the fourth pressure sensor 36 are acquired, and the opening degrees LEV 11 and LEV 12 are indicated to the first expansion device 11 and the second expansion device 12, respectively. To notify.

FIG. 7 is a first flowchart showing a process of determining the opening degree LEV6a of the indoor expansion device 6a of the indoor unit 52a according to the embodiment of the present invention. FIG. 7 shows the process when the indoor unit 52a is in the cooling operation.
The opening degree LEV 6 a of the indoor expansion device 6 a is controlled by a controller that controls the entire air conditioning apparatus 100, and in this example, is controlled by the outdoor controller 201. As shown in FIG. 7, when the operation of the indoor unit 52a is started, the outdoor controller 201 acquires the opening LEV6 at the start of the operation of the opening LEV6a of the indoor expansion device 6a and measures the timer t. Start.

  In step S1A, the outdoor controller 201 determines whether the reference time tm0 has elapsed, and if it is determined that the reference time tm0 has elapsed (Yes in step S1A), the process proceeds to step S2A and the timer t It resets to zero and it transfers to step S3A.

In step S3A, the outdoor controller 201 acquires the temperature T33a and the temperature T34a detected by the first temperature sensor 33a and the second temperature sensor 34a. The temperature T33a and the temperature T34a represent the saturation temperature of the refrigerant and the temperature of the refrigerant, respectively.
In step S4A, the indoor controller 202a calculates a temperature difference SH between the temperature T34a and the temperature T33a.

In step S5A, the outdoor controller 201 calculates a difference ΔSH between the temperature difference SH and a preset target value temperature difference SHm.
In step S6A, the indoor controller 202a calculates a correction value ΔLEV6a of the opening degree LEV6a of the indoor expansion device 6a. The correction value ΔLEV 6a may be obtained, for example, by calculating the coefficient k1 in advance by a test or the like and multiplying the coefficient k1 by the temperature difference ΔSH.

In step S7A, the outdoor controller 201 sets an opening degree obtained by adding the correction value ΔLEV6a to the current opening degree LEV6a of the indoor expansion device 6a as a new opening degree LEV6a of the indoor expansion device 6a.
In step S8A, the outdoor controller 201 determines whether the reference time tm1 has elapsed, and if it is determined that the reference time tm1 has elapsed (Yes in step S8A), the process ends. For the end of the process, for example, the indoor expansion device 6a may be fully closed. On the other hand, when the outdoor controller 201 determines that the reference time tm1 has not passed (No in step S8A), the process returns to step S1A, and repeats the processing from step S1A to step S8A for each reference time.

FIG. 8 is a second flowchart showing a process of determining the opening degree LEV 6a of the indoor expansion device 6a of the indoor unit 52a according to the embodiment of the present invention. FIG. 8 shows the process when the indoor unit 52a is in the heating operation.
The opening degree LEV 6 a of the indoor expansion device 6 a is controlled by a controller that controls the entire air conditioning apparatus 100, and in this example, is controlled by the outdoor controller 201. As shown in FIG. 8, when the operation of the indoor unit 52a is started, the outdoor controller 201 obtains the opening LEV6 at the start of the operation of the opening LEV6a of the indoor expansion device 6a and measures the timer t. Start.

  In step S1B, the outdoor controller 201 determines whether the reference time tm0 has elapsed, and if it is determined that the reference time tm0 has elapsed (Yes in step S1B), the process proceeds to step S2B and the timer t It resets to zero and it transfers to step S3B.

In step S3B, the outdoor controller 201 obtains the temperature T33a and the pressure P31 detected by the first temperature sensor 33a and the first pressure sensor 31 (step S3B1), and calculates the saturation temperature Tc31 from the pressure P31 (step S3B2) ).
In step S4B, the indoor controller 202a calculates a temperature difference SC between the temperature T33a and the saturation temperature Tc31.

In step S5B, the outdoor controller 201 calculates a difference ΔSC between the temperature difference SC and a preset target value temperature difference SCm.
In step S6B, the indoor controller 202a calculates a correction value ΔLEV6a of the opening degree LEV6a of the indoor expansion device 6a. The correction value ΔLEV 6a may be obtained, for example, by calculating the coefficient k2 in advance by a test or the like and multiplying the coefficient k2 by the temperature difference ΔSC.

In step S7B, the outdoor controller 201 sets an opening degree obtained by adding the correction value ΔLEV6a to the current opening degree LEV6a of the indoor expansion device 6a as a new opening degree LEV6a of the indoor expansion device 6a.
In step S8B, the outdoor controller 201 determines whether the reference time tm1 has elapsed, and if it is determined that the reference time tm1 has elapsed (Yes in step S8B), the process ends. For the end of the process, for example, the indoor expansion device 6a may be fully closed. On the other hand, when the outdoor controller 201 determines that the reference time tm1 has not passed (No in step S8B), the process returns to step S1B, and repeats the processing in steps S1B to S8B for each reference time.

  The process of determining the opening degree LEV 6a of the indoor expansion device 6a of the indoor unit 52a has been described above, but the determination of the opening degree LEV 6b of the indoor expansion device 6b of the indoor unit 52b is also performed by the same process.

FIG. 9 is a flowchart of control for suppressing vibration noise of the first check valves 15a and 15b and the second check valves 16a and 16b performed by the outdoor controller 201 and the relay controller 203 according to the embodiment of the present invention. It is. FIG. 9 shows processing immediately after startup of the compressor 1 during full heating operation or simultaneous cooling and heating operation of the air conditioning apparatus 100. Further, the opening degrees LEV 6 a and LEV 6 b of the indoor expansion devices 6 a and 6 b are determined by the above-described process.
As shown in FIG. 9, when the operation of the compressor 1 of the outdoor unit 51 is started in step S11, the outdoor controller 201 starts measurement of the timer t.

  In step S12, the relay device controller 203 sets the opening degree LEV11 of the first expansion device 11 to an initial opening degree LEV11ini set in advance. The initial opening LEV11 ini is an opening at which the pressure difference ΔP between the pressure P35 and the pressure P36 becomes equal to or greater than the reference value A, and is obtained in advance by a test or the like.

  In step S13, the outdoor controller 201 determines whether the reference time tm2 has elapsed, and when it is determined that the reference time tm2 has elapsed (Yes in step S13), resets the timer t in step S14. It transfers to step S15.

  In step S15, the relay controller 203 determines whether the pressure difference ΔP between the pressure P35 detected by the third pressure sensor 35 and the pressure P36 detected by the fourth pressure sensor 36 is less than the reference value A. to decide. If the relay controller 203 determines that the pressure difference ΔP is less than the reference value A (Yes in step S15), the process proceeds to step S16. On the other hand, when the relay controller 203 determines that the pressure difference ΔP is equal to or greater than the reference value A (No in step S15), the process proceeds to step S25.

  In step S16, the relay controller 203 adds the first correction value ΔLEV11 set in advance to the current opening degree LEV11 of the first drawing device 11 to the opening degree of the new first drawing device 11. It sets as LEV11, and it transfers to step S17. The first correction value ΔLEV11 is a negative value, and is a value in the direction in which the first diaphragm device 11 is closed. Then, by lowering the opening degree of the first expansion device 11, the pressure difference ΔP before and after the first expansion device 11 increases. Further, the first correction value ΔLEV11 is determined in advance by a test or the like.

  In step S17, the relay controller 203 determines whether the pressure difference ΔP between the pressure P35 detected by the third pressure sensor 35 and the pressure P36 detected by the fourth pressure sensor 36 is less than the reference value A. to decide. If the relay controller 203 determines that the pressure difference ΔP is less than the reference value A (Yes in step S17), the process proceeds to step S18. On the other hand, when the relay controller 203 determines that the pressure difference ΔP is equal to or greater than the reference value A (No in step S17), the process proceeds to step S25.

  In step S18, the relay controller 203 determines whether the current opening degree LEV11 of the first expansion device 11 is the minimum opening degree LEV11 min. If the relay controller 203 determines that the current opening degree LEV11 of the first expansion device 11 is the minimum opening degree LEV11 min (Yes in step S18), the process proceeds to step S19. On the other hand, when the relay controller 203 determines that the current opening degree LEV11 of the first expansion device 11 is not the minimum opening degree LEV11 min (No in step S18), the process returns to step S16.

  In step S19, the relay controller 203 adds the second correction value ΔLEV12 set in advance to the current opening degree LEV12 of the second drawing device 12 to the opening degree LEV12 of the new second drawing device 12. And the process proceeds to step S20. The second correction value ΔLEV12 is a positive value, and is a value in the direction in which the second diaphragm device 12 opens. Then, by increasing the opening degree of the second expansion device 12, the pressure P36 of the fourth pressure sensor 36 decreases, and the pressure difference ΔP between P35 and P36 increases. Further, the value of the second correction value ΔLEV12 is determined in advance by a test or the like.

  In step S20, the relay controller 203 determines whether the pressure difference ΔP between the pressure P35 detected by the third pressure sensor 35 and the pressure P36 detected by the fourth pressure sensor 36 is less than the reference value A. to decide. If the relay controller 203 determines that the pressure difference ΔP is less than the reference value A (Yes in step S20), the process proceeds to step S21. On the other hand, when the relay controller 203 determines that the pressure difference ΔP is equal to or greater than the reference value A (No in step S20), the process proceeds to step S25.

  In step S21, the relay controller 203 determines whether the current opening degree LEV12 of the second expansion device 12 is the maximum opening degree LEV12max. If the relay controller 203 determines that the current opening degree LEV12 of the second expansion device 12 is the maximum opening degree LEV12max (Yes in step S21), the process proceeds to step S22. On the other hand, when the relay controller 203 determines that the current opening degree LEV12 of the second expansion device 12 is not the maximum opening degree LEV12max (No in step S21), the process returns to step S19.

  In step S22, the outdoor controller 201 sets an operating frequency obtained by adding a preset third correction value ΔFa to the current operating frequency Fa of the compressor 1 as a new operating frequency Fa of the compressor 1, It transfers to step S23. As the operating frequency of the compressor 1 increases, the high pressure side pressure increases and the low pressure side pressure decreases. That is, P35 increases and P36 decreases, so the pressure difference ΔP increases. The value of the third correction value ΔFa is determined in advance by a test or the like.

  In step S23, the relay controller 203 determines whether the pressure difference ΔP between the pressure P35 detected by the third pressure sensor 35 and the pressure P36 detected by the fourth pressure sensor 36 is less than the reference value A. to decide. If the relay controller 203 determines that the pressure difference ΔP is less than the reference value A (Yes in step S23), the process proceeds to step S24. On the other hand, when the relay controller 203 determines that the pressure difference ΔP is equal to or greater than the reference value A (No in step S23), the process proceeds to step S25.

  In step S24, the outdoor controller 201 determines whether the current operating frequency Fa of the compressor 1 is the maximum operating frequency Famax. If the outdoor controller 201 determines that the current operating frequency Fa of the compressor 1 is the maximum operating frequency Famax (Yes in step S24), the process proceeds to step S25. On the other hand, when the outdoor controller 201 determines that the current operating frequency Fa of the compressor 1 is not the maximum operating frequency Famax (No in step S24), the process returns to step S22.

  In step S25, the outdoor controller 201 determines whether the reference time tm3 has elapsed, and if it is determined that the reference time tm3 has elapsed (Yes in step S25), the process ends. For the end of the process, for example, the operating frequency Fa of the compressor 1, the opening degree LEV11 of the first expansion device 11, and the opening degree LEV12 of the second expansion device 12 may be returned. On the other hand, when the outdoor controller 201 determines that the reference time tm3 has not passed (No in step S25), the process returns to step S13, and repeats the processing in steps S13 to S25 for every predetermined time. In step S25, the outdoor controller 201 may determine whether the pressure difference ΔP between the pressure P35 and the pressure P36 is less than a preset value.

  Thus, in the air conditioning apparatus 100 according to the present embodiment, by starting the operation of the first expansion device 11 of the first expansion device 11 of the relay device 53 at the initial opening LEV 11 ini set in advance when the compressor 1 is started. The first check valve 15a, 15b and the second check valve 16a, 16b can be operated with a pressure difference. Therefore, the valve bodies of the first check valve 15a, 15b and the second check valve 16a, 16b are vibrated to suppress the continuous occurrence of the sound of the valve body colliding with the valve seat and start up. Can be operated without producing unpleasant vibration noise.

  Further, during operation, the pressure difference ΔP between P35 and P36 is maintained at the reference value A or more, with the opening LEV11 of the first expansion device 11, the opening LEV12 of the second expansion device 12, and the operating frequency Fa of the compressor 1 Adjust to lean. By doing so, it is suppressed that the valve body of 1st non-return valve 15a, 15b and 2nd non-return valve 16a, 16b vibrates, and the sound which a valve body collides with a valve seat generate | occur | produces continuously. Can be operated without producing unpleasant vibration noise.

  Although the start of control is shown as the start of the compressor 1 in FIG. 9, the generation of vibration noise can be suppressed by starting the control from step S13 even if the air conditioner after the control is once operating. it can.

According to the air conditioning apparatus according to the present embodiment, the entire operation of the air conditioning apparatus 100 is controlled by the outdoor controller 201 of the outdoor unit 51.
In the present embodiment, three types of controllers, outdoor controller 201, indoor controllers 202a and 202b, and relay controller 203, are provided as controllers for controlling the operation of air conditioner 100. The number is not limited and may be less than three or more than three. The outdoor controller 201 and the relay controller 203 are examples of the “controller” in the present invention.

  Reference Signs List 1 compressor, 2 outdoor heat exchanger, 3 flow path switching device, 4 accumulator, 5a indoor heat exchanger, 5b indoor heat exchanger, 6a indoor throttling device, 6b indoor throttling device, 7a check valve, 7b check valve , 7c non-return valve, 7d non-return valve, 8 gas-liquid separator, 9a first on-off valve, 9b first on-off valve, 10a second on-off valve, 10b second on-off valve, 11 first throttling device, 12 second throttling device Throttle device, 13 first heat exchanger, 14 second heat exchanger, 15a first check valve, 15b first check valve, 16a second check valve, 16b second check valve, 20 first branch portion , 21 second branch part, 31 first pressure sensor, 32 second pressure sensor, 33a first temperature sensor, 33b first temperature sensor, 34a second temperature sensor, 34b second temperature sensor, 35 third pressure sensor, 36 4th pressure sensor, 51 outdoor uni G, 52a indoor unit, 52b indoor unit, 53 relays, 54 control units, 55a relay forks, 55b relays fork, 100 air conditioners, 101 low pressure piping, 102 high pressure piping, 103 first gas piping, 104 First liquid piping, 105a second liquid piping, 105b second liquid piping, 106a second gas piping, 106b second gas piping, 110 bypass piping, 111 relay first liquid piping, 112 relay gas piping, 113 relay Second liquid piping, 130 connection piping, 131 connection piping, 132 connection piping, 133 connection piping, 201 outdoor controller, 202a indoor controller, 202b indoor controller, 203 relay controller.

An air conditioner according to the present invention includes an outdoor unit having a compressor, a flow path switching device, and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger and an indoor expansion device, the outdoor unit, and The relay unit is provided between the indoor unit and the relay unit for controlling the flow of the refrigerant flowing into the indoor unit according to the operation state of the indoor unit, and each of the indoor units selects the cooling operation or the heating operation. Air conditioner capable of simultaneous operation of heating and cooling, wherein the relay is connected to the outdoor unit via a first refrigerant pipe and a second refrigerant pipe, and the indoor heat in the indoor unit is A first branch portion having an on-off valve selectively connecting one of the refrigerant inlet and outlet of the exchanger to the second refrigerant pipe via the first refrigerant pipe or the gas-liquid separator; Is connected to the gas-liquid separator via the first expansion device when the other of the refrigerant inlet and outlet of the indoor heat exchanger in the chamber is the refrigerant inlet, and the other of the refrigerant inlet and outlet of the indoor heat exchanger in the indoor unit is The pressure difference before and after the first expansion device becomes equal to or greater than a reference value at the time of starting the second branch portion having a check valve connected to the outlet side of the first expansion device when it becomes a refrigerant outlet And a controller configured to set an initial opening degree as the opening degree of the first expansion device , wherein the reference value is a value at which the valve body of the check valve does not fall by its own weight .

Claims (5)

An outdoor unit having a compressor, a flow path switching device, and an outdoor heat exchanger;
A plurality of indoor units having an indoor heat exchanger and an indoor expansion device;
The relay unit is provided between the outdoor unit and the indoor unit, and controls a flow of a refrigerant to be flowed into the indoor unit according to the operation state of the indoor unit.
The air conditioning apparatus is capable of simultaneous heating and cooling operation in which each of the indoor units can selectively perform a cooling operation or a heating operation,
The repeater is
It is connected to the outdoor unit via a first refrigerant pipe and a second refrigerant pipe,
A first branch portion having an open / close valve selectively connecting one of the refrigerant inlet and outlet of the indoor heat exchanger in the indoor unit to the second refrigerant pipe via the first refrigerant pipe or a gas-liquid separator;
When the other of the refrigerant inlet and outlet of the indoor heat exchanger in the indoor unit is a refrigerant inlet, the refrigerant is connected to the gas-liquid separator via a first expansion device, and the other of the refrigerant inlet and outlet of the indoor heat exchanger in the indoor unit A second branch having a check valve connected to the outlet side of the first expansion device when the refrigerant outlet is the
A controller comprising: an initial opening degree at which a pressure difference between the front and rear of the first expansion device becomes equal to or greater than a reference value at startup of the compressor, as an opening degree of the first expansion device. The repeater is
A pressure sensor for detecting a pressure difference before and after the first throttle device;
The controller
After setting the initial opening degree as the opening degree of the first expansion device,
If the pressure difference detected by the pressure sensor is less than the reference value, an opening degree obtained by adding a preset first correction value, which is a value in the closing direction, to the current opening degree of the first throttle device The air conditioner according to claim 1, wherein the air conditioner is set as an opening degree of the new first throttling device. The repeater is
The bypass pipe includes one end connected to the inlet side of the second branch and the other end connected to the first refrigerant pipe via a second expansion device.
The controller
After setting the opening degree obtained by adding the first correction value to the current opening degree of the first drawing device as a new opening degree of the first drawing device,
When the pressure difference detected by the pressure sensor is less than the reference value, and the current opening degree of the first expansion device is the minimum opening degree, the current opening degree of the second expansion device is opened. Setting an opening degree obtained by adding a second correction value set in advance, which is a value of the direction, as a new opening degree of the second diaphragm device,
When the pressure difference detected by the pressure sensor is less than the reference value and the current opening degree of the first expansion device is not the minimum opening degree, the current opening degree of the first expansion device The air conditioning apparatus according to claim 2, wherein the opening degree to which the correction value is added is set as a new opening degree of the first expansion device. The controller
After setting the opening degree obtained by adding the second correction value to the current opening degree of the second drawing device as a new opening degree of the second drawing device,
If the pressure difference detected by the pressure sensor is less than the reference value and the current opening degree of the second throttle device is the maximum opening degree, the current operating frequency of the compressor is set in advance Setting the operating frequency to which the third correction value has been added as the operating frequency of the new compressor,
When the pressure difference detected by the pressure sensor is less than the reference value, and the current opening degree of the second expansion device is not the maximum opening degree, the current opening degree of the second expansion device is The air conditioner according to claim 3, wherein an opening degree obtained by adding 2 correction values is set as a new opening degree of the second expansion device. The controller
After setting an operating frequency obtained by adding the third correction value to the current operating frequency of the compressor as a new operating frequency of the compressor,
When the pressure difference detected by the pressure sensor is less than the reference value and the current operating frequency of the compressor is not the maximum operating frequency, the third correction value is set to the current operating frequency of the compressor. The air conditioner according to claim 4, wherein the added operating frequency is set as a new operating frequency of the compressor.

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