JP6591071B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner having a relay that distributes a refrigerant supplied from a heat source unit to a plurality of indoor units.

In an air conditioner in which heating operation or cooling operation is individually performed in a plurality of indoor units, for example, heat, cold, or both heat and cold created in a heat source device are efficiently supplied to a plurality of loads. Refrigerant circuit and structure. Such an air conditioner is applied to, for example, a building multi-air conditioner. Conventionally, in an air conditioner such as a multi air conditioner for buildings, for example, a cooling operation or a heating operation is performed by circulating a refrigerant between an outdoor unit that is a heat source unit arranged outdoors and an indoor unit arranged indoors. Is executed. Specifically, the air-conditioning target space is cooled or heated by air cooled by heat absorbed by the refrigerant or air heated by heat released from the refrigerant. As a refrigerant used in such an air conditioner, for example, an HFC refrigerant, that is, a hydrofluorocarbon refrigerant is often used. An air conditioner using a natural refrigerant such as carbon dioxide, that is, CO ₂ has also been proposed.

  Here, there has been proposed an air conditioner in which a heat source unit and a plurality of indoor units are connected, and refrigerant is supplied from the heat source unit to the plurality of indoor units to perform simultaneous cooling and heating operations. The air conditioner described in Patent Literature 1 includes a first branch pipe configured from a first connection pipe and a three-way switching valve that is switchably connected to the first connection pipe or the second connection pipe. A second branch pipe that connects the second connection pipe and the second connection pipe on the indoor unit side via six check valves;

  The air conditioner described in Patent Document 1 switches a refrigerant flowing into an indoor unit that is in a heating operation and a refrigerant flowing in from an indoor unit that is in a cooling operation into a three-way switching valve of a first branching section. Is going on. In addition, each check valve constituting the second branch portion allows the refrigerant to flow in one direction in accordance with the switching of the refrigerant at the first branch portion. Therefore, when the indoor unit performs a cooling operation, the first port of the connection port of the three-way switching valve is closed, and the second port and the third port are opened. In addition, when the indoor unit performs a heating operation, the second port of the connection port is closed, and the first port and the third port are opened.

  When the indoor unit performs a cooling operation, the refrigerant has a low pressure in the first connection pipe and a high pressure in the second connection pipe. Therefore, the refrigerant is high in the connection pipe on the first port side of the connection port of the three-way switching valve. The connection piping on the mouth side is in a low pressure state, and the connection piping on the third port side is in a low pressure state. In the cooling operation, the refrigerant is controlled by the superheat amount on the outlet side of the indoor heat exchanger, and the refrigerant in the low-pressure gas state flows through the first connection pipe on the indoor unit side.

  Further, when the indoor unit is in a heating operation, the refrigerant has a low pressure in the first connection pipe and a high pressure in the second connection pipe. Therefore, the refrigerant is high in the connection pipe on the first port side of the connection port of the three-way switching valve. The connection piping on the mouth side is in a low pressure state, and the connection piping on the third port side is in a high pressure state. Further, during the heating operation, the refrigerant is controlled by the subcooling amount on the outlet side of the indoor heat exchanger, and the refrigerant in the high-temperature and high-pressure gas state flows through the first connection pipe on the indoor unit side. Here, the refrigerant | coolant of a high temperature / high pressure liquid state exists in the connection piping from an indoor side heat exchanger and an indoor side heat exchanger to a 1st flow control apparatus.

  Therefore, when switching the operation of the indoor unit from the heating operation to the cooling operation, the high-temperature high-pressure gas refrigerant and the high-temperature high-pressure liquid refrigerant that have flowed during the heating pass through the three-way switching valve and are in a low-pressure state. It flows into the connecting pipe. At that time, in the three-way switching valve, refrigerant flow noise is generated due to the balance between the high pressure and the low pressure of the refrigerant passing through the three-way switching valve. In particular, the flow noise of the high-temperature high-pressure liquid refrigerant is increased.

  Therefore, an air conditioner using an electromagnetic valve, particularly an electromagnetic on-off valve, instead of the three-way switching valve has been proposed. In the air conditioner described in Patent Document 2, the second electromagnetic valve is used for heating, the first electromagnetic valve and the third electromagnetic valve with an orifice function added are used for cooling, When switching from the heating operation to the cooling operation, the refrigerant is allowed to flow stepwise through the first solenoid valve and the third solenoid valve. Thereby, it is trying to reduce the flow noise of the high-temperature high-pressure liquid refrigerant. Moreover, in the air conditioning apparatus described in Patent Document 2, the flow noise of the refrigerant is reduced by reducing the opening diameter of the flow control device, performing pulse control of the flow control device, and reducing the opening diameter of the third electromagnetic valve. Trying to reduce. There has also been proposed an air conditioner that uses a solenoid valve, particularly an electromagnetic on-off valve, and is compact. In this air conditioner, the second electromagnetic valve is used for heating, and the first electromagnetic valve, the third electromagnetic valve, and the orifice are used for cooling. Here, the orifice attempts to equalize the high-pressure side pipe and the low-pressure side pipe by bypassing the high pressure and the low pressure, thereby reducing the flow noise of the refrigerant. That is, in this air conditioner, when switching from the heating operation to the cooling operation, the refrigerant is allowed to flow stepwise through the orifice, the third electromagnetic valve, and the first electromagnetic valve. Thereby, it is trying to reduce the flow noise of the high-temperature high-pressure liquid refrigerant. Furthermore, in a conventional air conditioner, when switching from heating operation to defrosting operation, the refrigerant flows from the heat source unit to the relay unit, then flows out to the liquid outflow side of the gas-liquid separator and passes through the bypass circuit. Return to the heat source machine. At this time, after the refrigerant flows out to the liquid outflow side of the gas-liquid separator, the first heat exchange unit, the flow rate control device, the second heat exchange unit, the flow rate control device, the second heat exchange unit, the first It flows in the order of the heat exchange part.

Japanese Patent No. 4350836 JP 09-0428804 A

  However, in the conventional air conditioner, there is a possibility that the refrigerant flowing in the flow rate control device on the liquid outflow side of the gas-liquid separator generates a flow noise during the defrosting operation.

  The present invention has been made in order to solve the above-described problems, and is an air conditioner that suppresses the generation of flow noise in the flow rate control device on the liquid outflow side of the gas-liquid separator during the defrosting operation. A device is provided.

An air conditioner according to the present invention includes a heat source device having a compressor, a flow path switching valve, and a heat source side heat exchanger, and a first flow rate control device and an indoor side heat exchanger, respectively, for cooling operation or heating operation. Connected to the heat source unit by a plurality of indoor units, a first connection pipe and a second connection pipe, and connected to a plurality of indoor units by a plurality of gas branch pipes and a plurality of liquid branch pipes, respectively, and supplied from the heat source unit A relay that distributes the refrigerant to be delivered to a plurality of indoor units, and a controller that controls the operation of the relay, and the relay is in a state of the refrigerant flowing between the liquid branch pipe and the second connection pipe A liquid state detection unit for detecting the refrigerant, and the refrigerant flowing in is separated into a gas refrigerant and a liquid refrigerant, the inflow side is connected to the second connection pipe, the gas outflow side is connected to the gas branch pipe, and the liquid outflow A gas-liquid separator whose side is connected to the liquid branch pipe and the first connection pipe; Provided on the liquid outflow side of the liquid separation device, closed at the time of heating operation, opened at the time of cooling operation, provided at the downstream side of the second flow rate control device, a second flow rate control device for adjusting the flow rate of the refrigerant, A third flow rate control device for adjusting the flow rate of the refrigerant, and a plurality of cooling devices, one of which is connected to the gas branch pipe, the other is connected to the first connection pipe, is opened during the cooling operation, and is closed during the heating operation. A solenoid valve, one connected to the gas branch pipe, the other connected to the gas outflow side of the gas-liquid separator, opened during heating operation, and closed during cooling operation, and controlled The unit switches the flow path switching valve when the heat source unit switches from the heating operation to the defrosting operation, closes the heating electromagnetic valve, and opens the second flow control device, and the second flow rate Detected by the liquid state detector when refrigerant flows through the control device Based on the state of the refrigerant, a determination means for determining whether the refrigerant flowing in the second flow control device or the third flow control device generates a flow noise, and the second flow control device by the determination means or if the refrigerant flowing through the third flow control device is determined to generate flow noise, have a, a timing control means for controlling the valve control means to sequentially open the solenoid valve and the cooling solenoid valve for heating The timing control means controls the valve control means so as to first open the cooling solenoid valve having a small Cv value among the plurality of cooling solenoid valves .

  According to the present invention, when it is determined that the refrigerant flowing through the second flow control device or the third flow control device generates a flow noise during the defrosting operation, the heating solenoid valve and the cooling solenoid valve are sequentially opened. Is done. Thereby, since the amount of the refrigerant flowing through the second flow control device or the third flow control device is reduced, the refrigerant flowing through the second flow control device or the third flow control device generates a flow sound. Is suppressed. Therefore, the quietness of the air conditioner is improved.

It is a circuit diagram which shows the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a block diagram which shows the control part 70 of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the state at the time of the cooling operation of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the state at the time of the heating operation of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the state at the time of the cooling main operation | movement of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the state at the time of heating main operation | movement of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the 1st state at the time of the defrost driving | operation of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the 2nd state at the time of the defrost driving | operation of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the air conditioning apparatus 100 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the conventional air conditioning apparatus. It is a flowchart which shows operation | movement of the air conditioning apparatus 100 which concerns on the 1st modification of Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the air conditioning apparatus 100 which concerns on the 2nd modification of Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the air conditioning apparatus 100 which concerns on the 3rd modification of Embodiment 1 of this invention.

Embodiment 1 FIG.
Hereinafter, embodiments of an air-conditioning apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing an air-conditioning apparatus 100 according to Embodiment 1 of the present invention. The air conditioner 100 will be described with reference to FIG. As shown in FIG. 1, the air conditioning apparatus 100 includes a heat source unit A, a plurality of indoor units B, C, and D, a relay unit E, and a control unit 70. In addition, in this Embodiment 1, although illustrated about the case where the three indoor units B, C, and D are connected to one heat source unit A, the number of the heat source units A may be two or more. Further, the number of indoor units may be three or more.

  As shown in FIG. 1, the air conditioner 100 is configured by connecting a heat source unit A, indoor units B, C, and D, and a relay unit E. The heat source unit A has a function of supplying hot or cold heat to the three indoor units B, C, and D. The three indoor units B, C, and D are connected in parallel to each other and have the same configuration. The indoor units B, C, and D have a function of cooling or heating an air-conditioning target space such as a room by using the heat or cold supplied from the heat source device A. The relay unit E is interposed between the heat source unit A and the indoor units B, C, D, and has a function of switching the flow of refrigerant supplied from the heat source unit A in response to requests from the indoor units B, C, D. Have. The air conditioner 100 also includes a liquid state detection unit 81 that detects the state of the refrigerant, and a gas state detection unit 80. The liquid state detection unit 81 includes, for example, a liquid outflow pressure detection sensor 25 and a downstream liquid outflow pressure detection sensor 26. Further, the gas state detection unit 80 includes a merged pressure detection sensor 56. The gas state detection unit 80 includes a gas pipe temperature detection sensor 53, a liquid pipe temperature detection sensor 54, a liquid outflow pressure detection sensor 25, a downstream side liquid outflow pressure detection sensor 26, a merging pressure detection sensor 56, and a discharge pressure detection sensor 18. You may have.

(Heat source machine A)
The heat source machine A includes a variable capacity compressor 1, a flow path switching valve 2 that switches a refrigerant flow direction in the heat source machine A, a heat source side heat exchange unit 3 that functions as an evaporator or a condenser, and a flow path switching valve 2. The accumulator 4 connected to the suction side of the compressor 1 and the heat source side flow path adjustment unit 40 that restricts the flow direction of the refrigerant are provided. The heat source unit A has a function of supplying hot or cold to the indoor units B, C, and D. Although the flow path switching valve 2 is illustrated as a four-way valve, it may be configured by combining a two-way valve or a three-way valve.

  The heat source side heat exchange unit 3 includes a first heat source side heat exchanger 41 and a second heat source side heat exchanger 42, a heat source side bypass passage 43, a first electromagnetic on-off valve 44, a second electromagnetic on-off valve 45, A third electromagnetic on-off valve 46, a fourth electromagnetic on-off valve 47, a fifth electromagnetic on-off valve 48, and a heat source side blower 20 are provided.

  The first heat source side heat exchanger 41 and the second heat source side heat exchanger 42 have the same heat transfer area and are connected in parallel to each other. The heat source side bypass passage 43 is connected in parallel to the first heat source side heat exchanger 41 and the second heat source side heat exchanger 42. The refrigerant flowing through the heat source side bypass passage 43 does not pass through the first heat source side heat exchanger 41 and the second heat source side heat exchanger 42 and is not heat-exchanged.

  The first electromagnetic on-off valve 44 is provided on one end side of the first heat source side heat exchanger 41. The second electromagnetic opening / closing valve 45 is provided on the other end side of the first heat source side heat exchanger 41. The third electromagnetic opening / closing valve 46 is provided on one end side of the second heat source side heat exchanger 42. The fourth electromagnetic opening / closing valve 47 is provided on the other end side of the second heat source side heat exchanger 42. The fifth electromagnetic opening / closing valve 48 is provided in the heat source side bypass passage 43.

  The heat source side flow path adjustment unit 40 includes a third check valve 32, a fourth check valve 33, a fifth check valve 34, and a sixth check valve 35. The third check valve 32 is provided in a pipe that connects the heat source side heat exchange unit 3 and the second connection pipe 7, and allows the refrigerant to flow from the heat source side heat exchange unit 3 to the second connection pipe 7. Allow. The fourth check valve 33 is provided in a pipe that connects the flow path switching valve 2 of the heat source apparatus A and the first connection pipe 6, and the refrigerant that flows from the first connection pipe 6 to the flow path switching valve 2. Allow distribution. The fifth check valve 34 is provided in a pipe connecting the flow path switching valve 2 of the heat source apparatus A and the second connection pipe 7, and the refrigerant flowing from the flow path switching valve 2 to the second connection pipe 7 is provided. Allow distribution. The sixth check valve 35 is provided in a pipe connecting the heat source side heat exchange unit 3 and the first connection pipe 6, and allows the refrigerant to flow from the first connection pipe 6 toward the heat source side heat exchange unit 3. Allow.

  The heat source machine A is provided with a discharge pressure detection sensor 18. The discharge pressure detection sensor 18 is provided in a pipe connecting the flow path switching valve 2 and the discharge side of the compressor 1, and detects the discharge pressure of the compressor 1. The heat source side blower 20 varies the amount of air blown to the heat source side heat exchange unit 3 and controls the heat exchange capacity. The heat source machine A performs a defrosting operation when frost adheres to the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42 during the heating operation.

(Indoor units B, C, D)
The indoor units B, C, and D are provided with an indoor heat exchanger 5 and a first flow rate control device 9 that function as a condenser or an evaporator, and air conditioning such as indoors by hot or cold supplied from the heat source unit A. It has a function of cooling or heating the target space. The first flow rate control device 9 is controlled by the superheat amount on the outlet side of the indoor heat exchanger 5 during cooling. Moreover, the 1st flow control apparatus 9 is controlled by the subcooling amount by the side of the exit of the indoor side heat exchanger 5 at the time of heating.

  The indoor units B, C, and D are provided with a gas pipe temperature detection sensor 53 and a liquid pipe temperature detection sensor 54. The gas pipe temperature detection sensor 53 is provided between the indoor heat exchanger 5 and the relay E, and is connected to the gas branch pipes 6b, 6c, and 6d that connect the indoor heat exchanger 5 and the relay E. The temperature of the circulating refrigerant is detected. The liquid pipe temperature detection sensor 54 is provided between the indoor heat exchanger 5 and the first flow control device 9, and is a liquid that connects the indoor heat exchanger 5 and the first flow control device 9. The temperature of the refrigerant flowing through the branch pipes 7b, 7c, 7d is detected.

(Repeater E)
The relay machine E includes a first branch unit 10, a second flow rate control device 13, a second branch unit 11, a gas-liquid separation device 12, a heat exchange unit 8, and a third flow rate control device 15. The relay unit E is interposed between the heat source unit A and the indoor units B, C, D, and switches the flow of the refrigerant supplied from the heat source unit A in response to a request from the indoor units B, C, D. It has a function of distributing the refrigerant supplied from the machine A to the plurality of indoor units B, C, and D.

  Here, the flow path switching valve 2 of the heat source device A and the relay device E are connected by the first connection pipe 6. The indoor side heat exchanger 5 of the indoor units B, C, and D and the relay unit E are connected by gas branch pipes 6b, 6c, and 6d on the indoor units B, C, and D sides corresponding to the first connection pipe 6. ing. The heat source side heat exchange unit 3 of the heat source machine A and the relay machine E are connected by a second connection pipe 7 having a diameter smaller than that of the first connection pipe 6. The indoor side heat exchanger 5 and the relay unit E of the indoor units B, C, and D are connected via the first connection pipe 6 and the indoor units B and C corresponding to the second connection pipe 7. , D side liquid branch pipes 7b, 7c and 7d.

  One of the first branch portions 10 is connected to the gas branch pipes 6b, 6c, 6d, and the other is connected to the first connection pipe 6 and the second connection pipe 7, and the refrigerant flow direction during the cooling operation is The flow direction of the refrigerant during the heating operation is different. The first branching unit 10 includes a first cooling electromagnetic valve 31a, a second cooling electromagnetic valve 31b, and a heating electromagnetic valve 30. The first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b are connected in parallel with each other, one of which is connected to the gas branch pipes 6b, 6c, 6d, and the other of which is the first. It is connected to the connecting pipe 6 and is opened during cooling operation and closed during heating operation. The first cooling electromagnetic valve 31a, the second cooling electromagnetic valve 31b, and the heating electromagnetic valve 30 are not limited to valve types, and may be, for example, an electric valve.

  In addition, one of the heating solenoid valves 30 is connected to the gas branch pipes 6b, 6c and 6d, and the other is connected to the second connection pipe 7, and is opened during the heating operation and closed during the cooling operation. . Hereinafter, the first cooling electromagnetic valve 31 a and the second cooling electromagnetic valve 31 b connected to the indoor units B, C, and D may be collectively referred to as a cooling electromagnetic valve 31. The number of cooling solenoid valves 31 is not limited to two, and may be three or more. Further, the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b may have the same or different Cv values. Further, the cooling electromagnetic valves 31 connected to the indoor units B, C, and D may have the same or different Cv values.

  One of the second branch portions 11 is connected to the liquid branch pipes 7b, 7c, and 7d, and the other is connected to the first connection pipe 6 and the second connection pipe 7, and the flow direction of the refrigerant during the cooling operation is The flow direction of the refrigerant during the heating operation is different. The second branch portion 11 includes first check valves 50b, 50c, and 50d and second check valves 52b, 52c, and 52d.

  The first check valves 50b, 50c, and 50d are provided in a number corresponding to the number of indoor units B, C, and D, respectively. The first check valves 50b, 50c, 50d are provided in the liquid branch pipes 7b, 7c, 7d, respectively, and allow the refrigerant to flow from the second connection pipe 7 to the liquid branch pipes 7b, 7c, 7d. To do.

  The second check valves 52b, 52c, and 52d are provided in a number corresponding to the number of indoor units B, C, and D, respectively. The second check valves 52b, 52c, 52d are connected in parallel to the first check valves 50b, 50c, 50d in the liquid branch pipes 7b, 7c, 7d, respectively, and the liquid branch pipes 7b, 7c, The refrigerant is allowed to flow from 7d toward the second connection pipe 7.

  The gas-liquid separator 12 separates the refrigerant in the gas state and the refrigerant in the liquid state, the inflow side is connected to the second connection pipe 7, the gas outflow side is connected to the first branch portion 10, and the liquid The outflow side is connected to the second branch portion 11.

  The heat exchange unit 8 includes a first heat exchange unit 19 and a second heat exchange unit 16. The second flow rate control device 13 is configured by, for example, an electric expansion valve that can be freely opened and closed. The second flow control device 13 is closed during the heating operation and opened during the cooling operation. Here, the gas-liquid separator 12 and the second branching unit 11 are connected via a first heat exchange unit 19, a second flow rate control device 13, and a second heat exchange unit 16. Further, the second branch portion 11 and the first connection pipe 6 are connected by a first bypass pipe 14. The third flow rate control device 15 is provided in the first bypass pipe 14 on the downstream side of the second flow rate control device 13, and is configured by, for example, an electric expansion valve that can be freely opened and closed. Here, the 2nd branch part 11 and the 1st connection piping 6 are connected via the 3rd flow control device 15, the 2nd heat exchange part 16, and the 1st heat exchange part 19.

  That is, the first heat exchange unit 19 heats the upstream side of the second flow rate control device 13 in the second connection pipe 7 and the downstream side of the second heat exchange unit 16 in the first bypass pipe 14. To be exchanged. The second heat exchange unit 16 heats the downstream side of the second flow rate control device 13 in the second connection pipe 7 and the downstream side of the third flow rate control device 15 in the first bypass pipe 14. To be exchanged. Thus, the gas-liquid separator 12 has the gas outflow side connected to the heating solenoid valve 30 and the liquid outflow side connected to the liquid branch pipes 7 b, 7 c, 7 d and the first connection pipe 6.

  In addition, the downstream side of the first check valves 50b, 50c, 50d in the liquid branch pipes 7b, 7c, 7d, the downstream side of the second flow rate control device 13 in the second connection pipe 7, and the second The upstream side of the heat exchange unit 16 is connected by a second bypass pipe 51. Then, the pipes connected to the liquid branch pipes 7 b, 7 c, 7 d in the second bypass pipe 51 and the pipes connected to the second connection pipe 7 in the second bypass pipe 51 merge on the way.

  The second check valves 52 b, 52 c and 52 d are connected to the liquid branch pipes 7 b, 7 c and 7 d in the second bypass pipe 51 and the second connection pipe 7 in the second bypass pipe 51. It is provided on the upstream side from the portion where the pipe connected to the pipe joins. The flow path from the second connection pipe 7 to the first flow control device 9 via the liquid branch pipes 7b, 7c, 7d provided with the first check valves 50b, 50c, 50d is the first flow path. The refrigerant flow path is configured and the second flow rate from the first flow rate control device 9 through the second bypass pipe 51 provided with the liquid branch pipes 7b, 7c, 7d and the second check valves 52b, 52c, 52d. The flow path leading to the connection pipe 7 constitutes the second refrigerant flow path.

  Further, the relay E is provided with a liquid outflow pressure detection sensor 25, a downstream side liquid outflow pressure detection sensor 26, and a merging pressure detection sensor 56. The liquid outflow pressure detection sensor 25 is provided between the first heat exchange unit 19 and the second flow control device 13 in the second connection pipe 7, and is a refrigerant on the liquid outflow side of the gas-liquid separation device 12. The pressure is detected. The downstream liquid outflow pressure detection sensor 26 is provided between the second flow rate control device 13 and the second heat exchange unit 16 in the second connection pipe 7, and the second flow rate control device 13 and the second flow rate control device 13. The pressure of the refrigerant | coolant between 2 heat-exchange parts 16 is detected. That is, the downstream liquid outflow pressure detection sensor 26 detects the pressure of the refrigerant flowing through the portion where the plurality of liquid branch pipes 7b, 7c, 7d join. The merge pressure detection sensor 56 is provided in a portion where the first connection pipe 6 and the first bypass pipe 14 are connected, and the liquid branch pipes 7b, 7c, 7d and the first connection pipe 6 are connected. The pressure of the refrigerant flowing through the part is detected.

(Refrigerant)
In the air conditioner 100, the inside of a pipe is filled with a refrigerant. Examples of the refrigerant include natural refrigerants such as carbon dioxide (CO ₂ ), hydrocarbons, and helium, CFC-free refrigerants that do not contain chlorine such as HFC410A, HFC407C, and HFC404A, and CFC-based refrigerants such as R22 and R134a that are used in existing products. Etc. are used. HFC407C is a non-azeotropic refrigerant mixture in which R32, R125, and R134a of HFC are mixed at a ratio of 23 wt%, 25 wt%, and 52 wt%, respectively. Moreover, the inside of the piping of the air conditioning apparatus 100 may be filled with a heat medium instead of the refrigerant. The heat medium is, for example, water, brine or the like.

(Control unit 70)
The control unit 70 controls the entire system of the air conditioning apparatus 100. Specifically, the control unit 70 includes a gas pipe temperature detection sensor 53, a liquid pipe temperature detection sensor 54, a liquid outflow pressure detection sensor 25, a downstream side liquid outflow pressure detection sensor 26, a merging pressure detection sensor 56, and a discharge pressure detection sensor. 18, based on the detection information received from 18 and an instruction from a remote controller (not shown), the driving frequency of the compressor 1, the heat source side blower 20 and the blower (not shown) provided in the indoor side heat exchanger 5. Rotation speed, switching of flow path switching valve 2, first electromagnetic on-off valve 44, second electromagnetic on-off valve 45, third electromagnetic on-off valve 46, fourth electromagnetic on-off valve 47, fifth electromagnetic on-off valve 48 , Opening / closing of the first cooling electromagnetic valve 31a, the second cooling electromagnetic valve 31b and the heating electromagnetic valve 30, the first flow control device 9, the second flow control device 13, and the third flow control device 15 To control the degree of opening.

  The control unit 70 may be mounted on any of the heat source unit A, the indoor units B, C, D, and the relay unit E, or may be mounted on all of them. Further, the control unit 70 may be mounted separately from the heat source unit A, the indoor units B, C, D, and the relay unit E. Moreover, when the air conditioning apparatus 100 has the some control part 70, it mutually connects so that communication is possible by radio | wireless or a wire communication.

  FIG. 2 is a block diagram showing the control unit 70 of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. As shown in FIG. 2, the control unit 70 includes valve control means 71, determination means 72, and timing control means 73. When the heat source machine A switches from the heating operation to the defrosting operation, the valve control means 71 switches the flow path switching valve 2 and closes the heating electromagnetic valve 30, and the second flow control device 13 and the third flow rate The control device 15 is opened. The valve control means 71 has a function of making the opening degree of the first flow control device 9 constant when the indoor units B, C, and D are switched from the heating operation to the cooling operation. For example, the valve control means 71 opens one of the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b.

  The determination unit 72 is configured to use the second flow rate control device 13 and the third flow rate control device based on the state of the refrigerant detected by the liquid state detection unit 81 when the refrigerant flows through the second flow rate control device 13. It is determined whether or not the refrigerant flowing through 15 generates a flow noise. Specifically, the determination means 72 uses the refrigerant pressure detected by the liquid outflow pressure detection sensor 25 and the downstream liquid outflow pressure detection sensor 26 so that the pressure difference before and after the second flow control device 13 is equal to or greater than a threshold value. In this case, it is determined that the flow sound of the refrigerant is generated. Note that the determination unit 72 may determine whether or not the refrigerant flowing through one of the second flow control device 13 and the third flow control device 15 generates a flow noise.

  In addition, when the refrigerant flows through the cooling electromagnetic valve 31, the determination unit 72 generates a flow sound of the refrigerant flowing through the heating electromagnetic valve 30 based on the state of the refrigerant detected by the gas state detection unit 80. Whether or not. In addition, when the refrigerant flows through the cooling electromagnetic valve 31, the determination unit 72 generates a flow sound of the refrigerant flowing through the cooling electromagnetic valve 31 based on the state of the refrigerant detected by the gas state detection unit 80. Whether or not. Specifically, the determination means 72 uses the refrigerant pressure detected by the liquid outflow pressure detection sensor 25 and the combined pressure detection sensor 56 to determine whether the pressure difference before and after the heating solenoid valve 30 or the cooling solenoid valve 31 is a threshold value. In the above case, it is determined that the flow noise of the refrigerant is generated. In addition, although the case where the state of the refrigerant flowing into the heating electromagnetic valve 30 or the cooling electromagnetic valve 31 is determined based on the detection information in the merging pressure detection sensor 56 is shown as an example, the present invention is not limited to this, and is described below. As will be described, information from other detection means may be used.

  For example, by predicting the differential pressure value at the inlet / outlet of the heating solenoid valve 30 or the cooling solenoid valve 31 based on information from the merging pressure detection sensor 56 and the gas pipe temperature detection sensor 53, the heating solenoid valve 30 or The state of the refrigerant flowing into the cooling electromagnetic valve 31 may be determined. Further, the state of the refrigerant flowing into the heating solenoid valve 30 or the cooling solenoid valve 31 may be determined from the outlet subcool value of the indoor heat exchanger 5 performing the heating operation before switching to the cooling operation. Good. Furthermore, the state of the refrigerant flowing into the heating electromagnetic valve 30 or the cooling electromagnetic valve 31 may be determined by predicting the refrigerant state of the indoor unit that has been stopped from the elapsed time since the heating was stopped. Furthermore, the state of the refrigerant flowing into the fourth flow control device 55 may be determined by combining these. The determination of the state of the refrigerant may be replaced by a thermistor that detects the temperature without using the merged pressure detection sensor 56.

  When it is determined by the determination means 72 that the refrigerant flowing through the second flow control device 13 and the third flow control device 15 generates a flow noise, the timing control means 73 has the heating solenoid valve 30 and the cooling solenoid valve 31. The valve control means 71 is controlled so as to open sequentially. Here, the timing control unit 73 opens the heating electromagnetic valve 30 when the determination unit 72 determines that the refrigerant flowing through the heating electromagnetic valve 30 does not generate a flow noise, and when the time threshold has elapsed, The valve control means 71 is controlled to open the electromagnetic valve 31 for use. Note that the timing control means 73 opens the heating solenoid valve 30 when the judgment means 72 determines that the refrigerant flowing through the heating solenoid valve 30 does not generate a flow noise, and the first threshold is reached when the time threshold value has elapsed. The valve control means 71 may be controlled so that both the cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b are opened. Note that the timing control unit 73 determines that the refrigerant flowing through one of the second flow rate control device 13 and the third flow rate control device 15 generates a flow noise, and the heating solenoid valve 30 and the cooling flow rate control unit 73. The valve control means 71 may be controlled so that the electromagnetic valves 31 are sequentially opened.

  On the other hand, the timing control unit 73 closes the heating electromagnetic valve 30 and opens the cooling electromagnetic valve 31 when the determination unit 72 determines that the refrigerant flowing in the heating electromagnetic valve 30 generates a flow noise. When the threshold value has elapsed, the valve control means 71 is controlled so as to open the heating solenoid valve 30. At this time, for example, by opening any of the cooling electromagnetic valves 31 connected to the respective liquid branch pipes 7b, 7c, 7d, the pressure of the refrigerant flowing through each cooling electromagnetic valve 31 is equalized. Further, the timing control means 73 sequentially opens the heating solenoid valves 30 connected to the gas branch pipes 6b, 6c, 6d, for example. In this case, the timing control means 73 may open one of the heating solenoid valves 30 that are closed, and then open two of the heating solenoid valves 30 that are closed. Two of the heating solenoid valves 30 being opened may be opened, and then one of the heating solenoid valves 30 being closed may be opened, or of the heating solenoid valves 30 being closed One of the heating solenoid valves 30 may be opened, and then one of the closed heating solenoid valves 30 may be opened, and then one of the closed heating solenoid valves 30 may be opened.

  The timing control means 73 opens the heating electromagnetic valve 30 and closes the cooling electromagnetic valve 31 when the determination means 72 determines that the refrigerant flowing through the heating electromagnetic valve 30 generates a flow noise. When the threshold value has elapsed, the valve control means 71 is controlled so as to open the cooling electromagnetic valve 31. At this time, for example, by opening any of the heating solenoid valves 30 connected to the respective liquid branch pipes 7b, 7c, 7d, the pressure of the refrigerant flowing through each heating solenoid valve 30 is equalized. Further, the timing control means 73 sequentially opens the cooling electromagnetic valves 31 connected to the gas branch pipes 6b, 6c, 6d, for example. In this case, the timing control means 73 may open one of the closed cooling electromagnetic valves 31 and then open all of the remaining cooling electromagnetic valves 31. One of the cooling electromagnetic valves 31 is opened, then one of the closed cooling electromagnetic valves 31 is opened, and then all of the remaining cooling electromagnetic valves 31 are closed. May be opened, or two of the closed cooling electromagnetic valves 31 may be opened, and then all the remaining of the closed cooling electromagnetic valves 31 may be opened.

  Further, the timing control means 73 opens the heating electromagnetic valve 30 and the cooling electromagnetic valve 31 when the determination means 72 determines that the refrigerant flowing through the heating electromagnetic valve 30 generates a flow noise. When the threshold value has elapsed, the valve control means 71 is controlled so as to open the cooling electromagnetic valve 31. At this time, for example, by opening any of the heating solenoid valves 30 connected to the respective liquid branch pipes 7b, 7c, 7d, the pressure of the refrigerant flowing through each heating solenoid valve 30 is equalized. The timing control means 73 opens the heating electromagnetic valve 30 and opens the cooling electromagnetic valve 31 when the determination means 72 determines that the refrigerant flowing through the heating electromagnetic valve 30 generates a flow noise. When the threshold value has elapsed, the valve control means 71 may be controlled to open the cooling electromagnetic valve 31. Further, the timing control means 73 sequentially opens the cooling electromagnetic valves 31 connected to the gas branch pipes 6b, 6c, 6d, for example. In this case, the timing control means 73 may open one of the closed cooling electromagnetic valves 31 and then open all of the remaining cooling electromagnetic valves 31. One of the cooling electromagnetic valves 31 is opened, then one of the closed cooling electromagnetic valves 31 is opened, and then all of the remaining cooling electromagnetic valves 31 are closed. May be opened, or two of the closed cooling electromagnetic valves 31 may be opened, and then all the remaining of the closed cooling electromagnetic valves 31 may be opened.

  Further, the timing control means 73 controls the valve control means 71 to open one of the plurality of cooling electromagnetic valves 31 when the indoor units B, C, D are switched from the heating operation to the cooling operation, Further, when it is determined by the determination means 72 that the flow noise of the refrigerant is generated, the valve control means 71 is controlled so as to open one of the closed electromagnetic valves 31 for cooling. Further, the timing control means 73 is configured to open one of the closed cooling electromagnetic valves 31 when the opening time threshold has elapsed after one of the closed cooling electromagnetic valves 31 is opened. The control means 71 may be controlled. For example, the timing control means 73 is configured to open the second cooling electromagnetic valve 31b when the opening time threshold has elapsed since the opening of the first cooling electromagnetic valve 31a by the valve control means 71. 71 is controlled.

  When the indoor unit B and the indoor unit C are switched from the heating operation to the cooling operation, the first cooling electromagnetic valve 31a, the second cooling electromagnetic valve 31b, and the indoor unit C connected to the indoor unit B Of the connected first cooling electromagnetic valve 31a and second cooling electromagnetic valve 31b, the valve control means 71 may open any of the cooling electromagnetic valves 31. For example, the timing control means 73 may control the valve control means 71 so as to open from the cooling electromagnetic valve 31 connected to the indoor unit B with a young address, for example, and the order of the cooling electromagnetic valves 31 to be opened. Does not matter.

  Further, when the valve control unit 71 opens the first cooling electromagnetic valve 31a connected to the indoor unit B, the timing control unit 73 sets the second cooling electromagnetic valve 31b connected to the indoor unit B. The valve control means 71 may be controlled so as to open the valve, the valve control means 71 may be controlled so as to open the first cooling electromagnetic valve 31a connected to the indoor unit C, or the indoor unit C The valve control means 71 may be controlled to open the second cooling electromagnetic valve 31b connected to the. That is, the timing control means 73 not only controls the valve control means 71 to open the cooling electromagnetic valve 31 connected to the indoor unit B to which the cooling electromagnetic valve 31 connected to the valve control means 71 is connected. The valve control means 71 may be controlled to open the cooling electromagnetic valve 31 connected to the other indoor unit C.

  In the first embodiment, among the indoor units B, C, and D that are switched from the heating operation to the cooling operation, the first cooling electromagnetic valve 31a connected to the indoor unit B with the younger address is opened, Thereafter, the second cooling electromagnetic valve 31b connected to the indoor unit B is opened. When the Cv value of the first cooling solenoid valve 31a is larger than the Cv value of the second cooling solenoid valve 31b, the second cooling solenoid valve 31b is opened first. When the Cv values of the second cooling electromagnetic valves 31b connected to the indoor units B, C, and D are different, the second cooling electromagnetic valve 31b having the smallest Cv value is opened. In the first embodiment, the case where the second cooling electromagnetic valve 31b connected to the indoor unit B is opened first by the valve control means 71 will be exemplified.

  In addition, the control unit 70 causes the refrigerant to flow through the indoor units B, C, and D when there is a possibility that the flow noise of the refrigerant flowing through the heating solenoid valve 30 or the cooling solenoid valve 31 is generated during the defrosting operation. The first flow control device 9 may be controlled. Thereby, since the quantity of the refrigerant | coolant which flows into the solenoid valve 30 for heating and the solenoid valve 31 for cooling reduces, generation | occurrence | production of a flow sound can be suppressed. Further, the diameter of the pipe connected to the second flow control device 13 and the third flow control device 15 may be increased. Thereby, since the pressure loss of the refrigerant | coolant which flows into the 2nd flow control apparatus 13 and the 3rd flow control apparatus 15 reduces, generation | occurrence | production of the flow sound of a refrigerant | coolant can be suppressed.

  Next, the operation of the air conditioning apparatus 100 will be described. The air conditioner 100 has a cooling only operation, a heating only operation, a cooling main operation, a heating main operation, and a defrosting operation as operation modes. The all-cooling operation is a mode in which all of the indoor units B, C, and D perform the cooling operation. The all heating operation is a mode in which all of the indoor units B, C, and D perform the heating operation. The cooling main operation is a mode in which the capacity of the cooling operation is larger than the capacity of the heating operation among the simultaneous cooling and heating operations. The heating main operation is a mode in which the heating operation capacity is larger than the cooling operation capacity in the simultaneous cooling and heating operation. The defrosting operation is the first heat source when frost adheres to the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42 when the all heating operation or the heating main operation is performed. In this mode, frost attached to the side heat exchanger 41 or the second heat source side heat exchanger 42 is removed.

(Cooling only)
FIG. 3 is a circuit diagram showing a state during the cooling only operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. First, the cooling only operation will be described. In the air conditioner 100, all of the indoor units B, C, and D are performing the cooling operation. As shown in FIG. 3, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the flow path switching valve 2 and the air blown by the heat source-side blower 20 having a variable blowing amount in the heat source-side heat exchange unit 3. Heat exchanged and condensed. Thereafter, the refrigerant flows in the order of the third check valve 32, the second connection pipe 7, the gas-liquid separation device 12, and the second flow rate control device 13, and further the second branch portion 11, the liquid branch pipe. Passes 7b, 7c, 7d and flows into indoor units B, C, D.

  Then, the refrigerant that has flowed into the indoor units B, C, and D is decompressed to a low pressure by the first flow control device 9 that is controlled by the superheat amount on the outlet side of the indoor heat exchanger 5. The decompressed refrigerant flows into the indoor heat exchanger 5 and exchanges heat with indoor air in the indoor heat exchanger 5 to evaporate. At that time, the room is cooled. The refrigerant in the gas state includes the gas branch pipes 6b, 6c and 6d, the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b of the first branching section 10, and the first connection piping. 6, sucked into the compressor 1 through the fourth check valve 33, the flow path switching valve 2 of the heat source device A, and the accumulator 4.

  In the cooling only operation, all heating solenoid valves 30 are closed. Further, both the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b are opened. Since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure, the refrigerant flows through the third check valve 32 and the fourth check valve 33.

  In this circulation cycle, a part of the refrigerant that has passed through the second flow rate control device 13 enters the first bypass pipe 14. Then, after the refrigerant is depressurized to a low pressure by the third flow control device 15, the refrigerant branches to the refrigerant that has passed through the second flow control device 13 in the second heat exchange unit 16, that is, the first bypass pipe 14. Heat is exchanged with the previous refrigerant to evaporate. Further, the first heat exchange unit 19 evaporates by exchanging heat with the refrigerant before flowing into the second flow rate control device 13. The evaporated refrigerant flows into the first connection pipe 6 and the fourth check valve 33 and is sucked into the compressor 1 through the flow path switching valve 2 and the accumulator 4 of the heat source apparatus A.

  On the other hand, in the first heat exchange section 19 and the second heat exchange section 16, heat exchange is performed with the refrigerant that flows into the first bypass pipe 14 and is decompressed to a low pressure by the third flow control device 15. The refrigerant having been cooled and sufficiently subcooled flows through the first check valves 50b, 50c, and 50d of the second branch portion 11 and flows into the indoor units B, C, and D that are to be cooled. Here, the control unit 70 sets the capacity of the variable capacity compressor 1 and the heat source side so that the evaporation temperatures of the indoor units B, C, and D and the condensation temperature of the heat source side heat exchange unit 3 become predetermined target temperatures. The air volume of the blower 20 is adjusted. For this reason, the target cooling capacity can be obtained in each of the indoor units B, C, and D. The condensation temperature of the heat source side heat exchange unit 3 is obtained as the saturation temperature of the pressure detected by the discharge pressure detection sensor 18.

(All heating operation)
FIG. 4 is a circuit diagram showing a state during the heating only operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Next, the all heating operation will be described. In the air conditioner 100, all of the indoor units B, C, and D perform the heating operation. As shown in FIG. 4, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the flow path switching valve 2, passes through the fifth check valve 34, the second connection pipe 7, the gas-liquid separator 12, The heating solenoid valve 30 of the first branching section 10 and the gas branch pipes 6b, 6c, and 6d are passed through in this order and flow into the indoor units B, C, and D. The refrigerant that has flowed into the indoor units B, C, and D is condensed and liquefied by exchanging heat with the indoor air. At that time, the room is heated. And the refrigerant | coolant which became this state passes the 1st flow control apparatus 9 controlled by the subcool amount of the exit side of each indoor side heat exchanger 5. FIG.

  The refrigerant that has passed through the first flow control device 9 flows into the second branch portion 11 from the liquid branch pipes 7b, 7c, 7d, and merges after passing through the second check valves 52b, 52c, 52d. The refrigerant merged at the second branch portion 11 is further guided between the second flow control device 13 and the second heat exchange portion 16 of the second connection pipe 7, and passes through the third flow control device 15. Pass through. Further, the refrigerant is depressurized to a low-pressure gas-liquid two-phase by the first flow control device 9 and the third flow control device 15.

  And the refrigerant | coolant decompressed to low pressure passes the 6th non-return valve 35 of the heat source machine A through the 1st connection piping 6, flows in into the heat source side heat exchange unit 3, and the heat source side with variable ventilation volume Heat exchange with the air blown by the blower 20 evaporates. The refrigerant that has evaporated to a gas state is sucked into the compressor 1 through the flow path switching valve 2 and the accumulator 4.

  In the all heating operation, both heating solenoid valves 30 are opened. In addition, both the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b are closed.

  Further, in this circulation cycle, the first connection pipe 6 is at a low pressure and the second connection pipe 7 is at a high pressure, so that the refrigerant flows through the fifth check valve 34 and the sixth check valve 35. Further, since the liquid branch pipes 7b, 7c, and 7d are higher in pressure than the second connection pipe 7 through the first check valves 50b, 50c, and 50d, the refrigerant does not pass through. Here, the control unit 70 sets the capacity of the variable capacity compressor 1 and the heat source side so that the condensation temperatures of the indoor units B, C, and D and the evaporation temperature of the heat source side heat exchange unit 3 become predetermined target temperatures. The air volume of the blower 20 is adjusted. For this reason, the target heating capacity can be obtained in each of the indoor units B, C, and D.

(Cooling operation)
FIG. 5 is a circuit diagram illustrating a state during the cooling main operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Next, the cooling main operation will be described. In the air conditioner 100, there is a cooling request from the indoor units B and C, and a heating request from the indoor unit D. As shown in FIG. 5, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the heat source side heat exchange unit 3 through the flow path switching valve 2 and is blown by the heat source side blower 20 having a variable blowing amount. Heat exchange with air results in a two-phase high temperature and high pressure state.

  Here, the control part 70 adjusts the capacity | capacitance of the capacity variable compressor 1, and the ventilation volume of the heat source side air blower 20 so that the evaporation temperature and condensation temperature of indoor unit B, C, D may become predetermined target temperature. To do. The control unit 70 also includes a first electromagnetic open / close valve 44, a second electromagnetic open / close valve 45, and a third electromagnetic open / close valve at both ends of the first heat source side heat exchanger 41 and the second heat source side heat exchanger 42. The heat transfer area is adjusted by opening and closing the valve 46 and the fourth electromagnetic opening / closing valve 47. Further, the control unit 70 opens and closes the fifth electromagnetic opening / closing valve 48 of the heat source side bypass passage 43 to flow the refrigerant flowing through the first heat source side heat exchanger 41 and the second heat source side heat exchanger 42. Adjust. Thereby, arbitrary heat exchange amount is obtained in the heat source side heat exchange unit 3, and in each of the indoor units B, C, D, a target heating capacity or cooling capacity can be obtained.

  The two-phase high-temperature and high-pressure refrigerant passes through the third check valve 32 and the second connection pipe 7 and is sent to the gas-liquid separator 12 of the relay machine E, where it is separated into a gas refrigerant and a liquid refrigerant. . Then, the gas refrigerant separated by the gas-liquid separator 12 passes through the heating solenoid valve 30 of the first branch portion 10 and the gas branch pipe 6d in this order, and flows into the indoor unit D to be heated, so that the indoor heat Heat is exchanged with room air in the exchanger 5 to be condensed and liquefied. At that time, the room is heated by the indoor unit D. Further, the refrigerant that has flowed out of the indoor heat exchanger 5 passes through the first flow rate control device 9 controlled by the subcooling amount on the outlet side of the indoor heat exchanger 5 of the indoor unit D, and is reduced in pressure to a second level. Flows into the branching section 11 of the. This refrigerant flows through the second bypass pipe 51 including the second check valve 52d to the downstream side of the second flow control device 13 of the second connection pipe 7.

  On the other hand, the liquid refrigerant separated by the gas-liquid separation device 12 passes through the second flow rate control device 13 controlled by the detection pressure of the liquid outflow pressure detection sensor 25 and the detection pressure of the downstream liquid outflow pressure detection sensor 26. Then, the refrigerant passes through the indoor unit D to be heated. Thereafter, it flows into the second heat exchange unit 16 and is cooled by the second heat exchange unit 16.

  Then, a part of the refrigerant cooled in the second heat exchange unit 16 passes through the first check valves 50b and 50c, passes through the liquid branch pipes 7b and 7c, and the indoor unit B to be cooled, Enter C. After the refrigerant flowing into the indoor units B and C enters the first flow rate control device 9 controlled by the superheat amount on the outlet side of the indoor heat exchangers 5 of the indoor units B and C, It enters into the indoor heat exchanger 5 and undergoes heat exchange to evaporate and gasify. At that time, each room is cooled by the indoor units B and C. Thereafter, the refrigerant flows into the first connection pipe 6 via the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b.

  On the other hand, the remainder of the refrigerant cooled by the second heat exchange unit 16 is such that the pressure difference between the detection pressure of the liquid outflow pressure detection sensor 25 and the detection pressure of the downstream liquid outflow pressure detection sensor 26 falls within a predetermined range. It passes through a controlled third flow control device 15. Then, after heat-exchanged by the 2nd heat exchange part 16 and the 1st heat exchange part 19, and evaporating, it flows in into the 1st connection piping 6, and merges with the refrigerant which passed indoor units B and C. The refrigerant merged in the first connection pipe 6 is sucked into the compressor 1 through the fourth check valve 33, the flow path switching valve 2, and the accumulator 4 of the heat source machine A.

  In the cooling main operation, the heating solenoid valve 30 connected to the indoor units B and C is closed. Moreover, the heating solenoid valve 30 connected to the indoor unit D is opened. Further, the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b connected to the indoor units B and C are opened. Furthermore, the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b connected to the indoor unit D are closed.

  Further, since the first connection pipe 6 is low pressure and the second connection pipe 7 is high pressure, the refrigerant flows through the third check valve 32 and the fourth check valve 33. Furthermore, since the liquid branch pipes 7b and 7c have a lower pressure than the second connection pipe 7 through the second check valves 52b and 52c, the refrigerant does not pass through. Furthermore, since the liquid branch pipe 7d has a higher pressure than the second connection pipe 7 through the first check valve 50d, the refrigerant does not pass therethrough. By the first check valve 50 and the second check valve 52, the refrigerant that has passed through the indoor unit D that requires heating does not pass through the second heat exchange unit 16, and the subcooling is not sufficiently applied. This prevents it from flowing into certain indoor units B and C.

(Heating-based operation)
FIG. 6 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention during a heating main operation. Next, the heating main operation will be described. In the air conditioner 100, there is a heating request from the indoor units B and C, and a cooling request from the indoor unit D. As shown in FIG. 6, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is sent to the relay device E through the flow path switching valve 2, the fifth check valve 34, and the second connection pipe 7. Through the gas-liquid separator 12. The refrigerant that has passed through the gas-liquid separator 12 passes through the heating solenoid valve 30 and the gas branch pipes 6b and 6c of the first branching section 10 in this order, and flows into the indoor units B and C that are to be heated. Heat is exchanged with room air in the exchanger 5 to be condensed and liquefied. At that time, each room is heated by the indoor units B and C. The condensed and liquefied refrigerant passes through the first flow rate control device 9 controlled by the subcooling amount on the outlet side of the indoor heat exchanger 5 of each of the indoor units C and D, and is slightly reduced in pressure to the second branching unit 11. Inflow.

  The refrigerant that has flowed into the second branching section 11 passes through the second bypass pipe 51 including the second check valves 52b and 52c and merges with the second connection pipe 7, and the second heat exchange section 16 To be cooled. A part of the refrigerant cooled by the second heat exchange unit 16 enters the indoor unit D that is going to be cooled through the first check valve 50d and the liquid branch pipe 7d. Then, the refrigerant that has entered the indoor unit D enters the first heat flow controller 9 controlled by the superheat amount on the outlet side of the indoor heat exchanger 5, is depressurized, and then enters the indoor heat exchanger 5. Heat exchanged to evaporate and gasify. At that time, the indoor unit D cools the room. Thereafter, the refrigerant flows into the first connection pipe 6 via the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b.

  On the other hand, the remainder of the refrigerant cooled by the second heat exchange unit 16 is such that the pressure difference between the detection pressure of the liquid outflow pressure detection sensor 25 and the detection pressure of the downstream liquid outflow pressure detection sensor 26 falls within a predetermined range. It passes through a controlled third flow control device 15. The refrigerant that has passed through the third flow control device 15 is evaporated by exchanging heat with the refrigerant that has come out of the indoor units B and C in the second heat exchange unit 16. Thereafter, the refrigerant merges with the refrigerant that has passed through the indoor unit D to be cooled, and flows into the sixth check valve 35 and the heat source side heat exchange unit 3 of the heat source machine A through the first connection pipe 6. The refrigerant that has flowed into the heat source side heat exchange unit 3 undergoes heat exchange with the air blown by the heat source side blower 20 with a variable air flow rate, evaporates and gasifies.

  Here, the control unit 70 sets the capacity of the compressor 1 with a variable capacity so that the evaporation temperature of the indoor unit D requiring cooling and the condensation temperature of the indoor units B and C requiring heating become the predetermined target temperatures. And the ventilation volume of the heat source side air blower 20 is adjusted. The control unit 70 also includes a first electromagnetic open / close valve 44, a second electromagnetic open / close valve 45, and a third electromagnetic open / close valve at both ends of the first heat source side heat exchanger 41 and the second heat source side heat exchanger 42. The heat transfer area is adjusted by opening and closing the valve 46 and the fourth electromagnetic opening / closing valve 47. Further, the control unit 70 opens and closes the fifth electromagnetic opening / closing valve 48 of the heat source side bypass passage 43 to change the flow rate of the refrigerant flowing through the first heat source side heat exchanger 41 and the second heat source side heat exchanger 42. adjust. Thereby, arbitrary heat exchange amount is obtained in the heat source side heat exchange unit 3, and the heating capacity or the cooling capacity targeted in each indoor unit B, C, D can be obtained. Then, the refrigerant is sucked into the compressor 1 through the flow path switching valve 2 and the accumulator 4 of the heat source apparatus A.

  In the heating main operation, the heating solenoid valve 30 connected to the indoor units B and C is opened. Moreover, the heating solenoid valve 30 connected to the indoor unit D is closed. Further, the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b connected to the indoor units B and C are closed. Furthermore, the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b connected to the indoor unit D are opened.

  Further, since the first connection pipe 6 is low pressure and the second connection pipe 7 is high pressure, the refrigerant flows through the fifth check valve 34 and the sixth check valve 35. The second flow rate control device 13 is closed. Furthermore, since the liquid branch pipes 7b and 7c have a higher pressure than the second connection pipe 7 in the first check valves 50b and 50c, the refrigerant does not pass through. Further, since the liquid branch pipe 7d has a lower pressure than the second connection pipe 7 in the second check valve 52d, the refrigerant does not pass through. By the first check valve 50 and the second check valve 52, the refrigerant that has passed through the indoor units B and C that require heating does not pass through the second heat exchange unit 16 and is not cooled sufficiently. It is prevented from flowing into the requested indoor unit D.

(Defrosting operation)
Next, the defrosting operation will be described. In the air conditioner 100, when the all heating operation or the heating main operation is performed, frost may adhere to the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42. In order to remove frost adhering to the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42, a defrosting operation is performed.

(First state)
FIG. 7 is a circuit diagram illustrating a first state during the defrosting operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Next, the first state of the defrosting operation will be described. When the defrosting operation is performed, the refrigerant flowing through the second flow control device 13 and the third flow control device 15 may generate a flow noise. The first state is a state in which the refrigerant flowing through the second flow control device 13 and the third flow control device 15 does not generate a flow noise. As shown in FIG. 7, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the flow path switching valve 2, and in the heat source side heat exchange unit 3, the first heat source side heat exchanger 41 or the second heat source. The frost which flows into the side heat exchanger 42 and adheres to the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42 is melted. In the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42, the refrigerant is condensed and liquefied by exchanging heat with air. Thereafter, the refrigerant flows in the order of the third check valve 32, the second connection pipe 7, and the gas-liquid separator 12.

  Here, the heating solenoid valve 30 is closed. For this reason, all the refrigerant flows out from the liquid outflow side of the gas-liquid separation device 12 and flows into the second flow rate control device 13 through the first heat exchange unit 19. The refrigerant is decompressed to a low pressure by the second flow control device 13, then flows into the second heat exchange unit 16, enters the first bypass pipe 14, and flows into the third flow control device 15. After the refrigerant is depressurized to a low pressure by the third flow control device 15, the refrigerant passes through the second flow control device 13 in the second heat exchange unit 16, that is, before branching to the first bypass pipe 14. Heat is exchanged with the refrigerant to evaporate. Further, the first heat exchange unit 19 evaporates by exchanging heat with the refrigerant before flowing into the second flow rate control device 13. The evaporated refrigerant flows into the first connection pipe 6 and the fourth check valve 33 and is sucked into the compressor 1 through the flow path switching valve 2 and the accumulator 4 of the heat source apparatus A.

(Second state)
FIG. 8 is a circuit diagram illustrating a second state during the defrosting operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Next, the second state of the defrosting operation will be described. When the defrosting operation is performed, the refrigerant flowing through the second flow control device 13 and the third flow control device 15 may generate a flow noise. The second state is a state in which the refrigerant flowing through the second flow control device 13 and the third flow control device 15 generates a flow noise. As shown in FIG. 8, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the flow path switching valve 2, and in the heat source side heat exchange unit 3, the first heat source side heat exchanger 41 or the second heat source. The frost which flows into the side heat exchanger 42 and adheres to the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42 is melted. In the first heat source side heat exchanger 41 or the second heat source side heat exchanger 42, the refrigerant is condensed and liquefied by exchanging heat with air. Thereafter, the refrigerant flows in the order of the third check valve 32, the second connection pipe 7, and the gas-liquid separator 12.

  Here, the heating solenoid valve 30 and the cooling solenoid valve 31 are opened. A part of the refrigerant flows out from the liquid outflow side of the gas-liquid separation device 12, passes through the first heat exchange unit 19, and flows into the second flow rate control device 13. The refrigerant is decompressed to a low pressure by the second flow control device 13, then flows into the second heat exchange unit 16, enters the first bypass pipe 14, and flows into the third flow control device 15. After the refrigerant is depressurized to a low pressure by the third flow control device 15, the refrigerant passes through the second flow control device 13 in the second heat exchange unit 16, that is, before branching to the first bypass pipe 14. Heat is exchanged with the refrigerant to evaporate. Further, the first heat exchange unit 19 evaporates by exchanging heat with the refrigerant before flowing into the second flow rate control device 13. The evaporated refrigerant reaches the first connection pipe 6.

  On the other hand, a part of the refrigerant flows out from the gas outflow side of the gas-liquid separator 12, passes through the heating electromagnetic valve 30, passes through the cooling electromagnetic valve 31, and reaches the first connection pipe 6. In the first connection pipe 6, the refrigerant that has flowed out from the liquid outflow side of the gas-liquid separation device 12 and the refrigerant that has flowed out from the gas outflow side of the gas-liquid separation device 12 merge. The merged refrigerant flows into the fourth check valve 33 and is sucked into the compressor 1 through the flow path switching valve 2 and the accumulator 4 of the heat source apparatus A.

  FIG. 9 is a flowchart showing the operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Next, the operation of the control unit 70 will be described. When the defrosting operation is performed, the refrigerant flowing through the second flow control device 13 and the third flow control device 15 may generate a flow noise. In the first embodiment, the control unit 70 prevents the refrigerant flowing through the second flow rate control device 13 and the third flow rate control device 15 from generating flow noise. Furthermore, in this Embodiment 1, the control part 70 suppresses that the refrigerant | coolant which flows into the solenoid valve 30 for heating generate | occur | produces a flow sound.

  When switching from the all heating operation or the heating main operation to the defrosting operation, as shown in FIG. 9, the flow path switching valve 2 is switched by the valve control means 71, the heating electromagnetic valve 30 is closed, and the second The flow control device 13 and the third flow control device 15 are opened (step ST100). Thereby, a refrigerant | coolant flows as a 1st state of a defrost operation, as shown in FIG. Next, the determination means 72 determines whether or not the refrigerant flowing through the second flow control device 13 and the third flow control device 15 generates a flow noise (step ST200). When it is determined that no flowing sound is generated (No in step ST200), the process returns to step ST200. On the other hand, when it is determined that the flow noise is generated (Yes in step ST200), the control is performed so as to shift to the second state of the defrosting operation and reduce the amount of the refrigerant flowing to the second flow control device 13. . As an example in which the refrigerant flowing through the second flow rate control device 13 generates flow noise, the refrigerant flow rate increases, the horsepower of the heat source machine A increases, the outdoor temperature decreases, and pressure loss improvement is required. It can be mentioned. Heating solenoid valve 30 is opened by valve control means 71 (step ST300).

  Thereafter, the cooling electromagnetic valve 31 is opened, and the second connection pipe 7 through which the high-pressure refrigerant flows and the first connection pipe 6 through which the low-pressure refrigerant flows are connected. Thus, when the differential pressure before and after the heating solenoid valve 30 and the cooling solenoid valve 31 is large, noise and impact may occur in the heating solenoid valve 30 and the cooling solenoid valve 31. Therefore, it is determined by the determination means 72 whether or not the refrigerant flowing through the heating solenoid valve 30 generates a flow noise (step ST400). When it is determined that no flowing sound is generated (No in step ST400), the process returns to step ST200. On the other hand, when it is determined that a flowing sound is generated (Yes in step ST400), the heating electromagnetic valve 30 is closed by the valve control means 71, and the cooling electromagnetic valve 31 is opened (step ST500). At this time, the cooling electromagnetic valves 31 may be opened one by one or all of the closed electromagnetic valves 31 may be opened. As a result, the pressure of the refrigerant flowing through each cooling electromagnetic valve 31 is equalized.

  Thereafter, it is determined whether or not the time threshold has elapsed (step ST600). When the time threshold has not elapsed (No in step ST600), the process returns to step ST600. On the other hand, when the time threshold has elapsed (Yes in step ST600), it is determined that the pressure has been sufficiently equalized, and the heating electromagnetic valve 30 is opened by the valve control means 71 (step ST700). Thereby, as shown in FIG. 8, a refrigerant | coolant flows as a 2nd state of a defrost operation. At this time, the heating solenoid valves 30 may be opened one by one or all of the closed heating solenoid valves 30 may be opened. When each of the closed heating solenoid valves 30 is opened one by one, the refrigerant flowing through the heating solenoid valve 30 is equalized. Then, control is continued.

  FIG. 10 is a flowchart showing the operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Next, the operation of the control unit 70 when the indoor units B, C, and D are switched from the heating operation to the cooling operation will be described. When the indoor units B, C, and D are switched from the heating operation to the cooling operation, the high-temperature and high-pressure gas refrigerant and the high-temperature and high-pressure liquid refrigerant that were flowing during the heating are used as the first cooling electromagnetic valve 31a and the second cooling. It passes through the electromagnetic valve 31b and flows into the first connection pipe 6 that is in a low pressure state during cooling. For this reason, there is a possibility that a large pressure difference occurs before and after the cooling electromagnetic valve 31, and refrigerant flow noise is generated around the cooling electromagnetic valve 31. In the first embodiment, the control unit 70 suppresses the flow noise of the refrigerant generated from the relay device E having the cooling electromagnetic valve 31. In the first embodiment, the addresses are assumed to be younger in the order of indoor units B, C, and D.

  As shown in FIG. 10, for example, when the indoor units B and C are switched from the heating operation to the cooling operation, the timing control means 73 causes the valve control means 71 to keep the opening degree of the first flow control device 9 constant. (Step ST1). Thereby, the pressure in the first connection pipe 6 is released to the second connection pipe 7. Accordingly, the pressure on the first connection pipe 6 side in the first cooling solenoid valve 31a and the second cooling solenoid valve 31b is reduced, and the pressure of the first connection pipe 6 and the pressure of the second connection pipe 7 are reduced. And head for equal pressure. In addition, the timing control unit 73 controls the valve control unit 71 so that the first cooling electromagnetic valve 31a connected to the indoor unit B is opened (step ST2).

FIG. 11 is a flowchart showing the operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Next, when the refrigerant flows through the second cooling electromagnetic valve 31 b opened by the valve control means 71 by the judging means 72, the flow sound is determined based on the state of the refrigerant detected by the gas state detection unit 80. Is determined (step ST3). Specifically, as shown in FIG. 11, it is determined by the determination means 72 whether or not the refrigerant pressure P detected by the merged pressure detection sensor 56 is equal to or higher than the pressure threshold value P ₀ (step ST31). . As shown in FIG. 10, when the pressure P of the refrigerant is less than the pressure threshold P ₀ (No in step ST3), since the difference between the pressure and the pressure in the second connecting pipe 7 of the first connection pipe 6 is small, It is determined that no refrigerant flow noise is generated, and the normal operation is resumed. On the other hand, if the pressure P of the refrigerant is greater than the pressure threshold P ₀ (Yes in step ST3), since the difference between the pressure of the pressure and the second connecting pipe 7 of the first connection pipe 6 is large, the refrigerant flow noise is It is determined that there is a risk of occurrence, and the process proceeds to step ST4. The determination means 72 uses the refrigerant pressure detected by the liquid outflow pressure detection sensor 25 and the combined pressure detection sensor 56, and if the pressure difference before and after the cooling electromagnetic valve 31 is greater than or equal to the threshold value, the flow sound of the refrigerant is generated. It may be determined that it occurs.

  In step ST4, it is confirmed by the timing control means 73 whether the opening time threshold has elapsed since the second cooling electromagnetic valve 31b was opened. If the opening time threshold has not elapsed (No in step ST4), step ST4 is repeated. When the open time threshold has elapsed (Yes in step ST4), the timing control means 73 selects the second cooling electromagnetic valve 31b connected to the indoor unit B having a young address (step ST5). Thereafter, the selected second cooling electromagnetic valve 31b is opened (step ST6). As a result, the plurality of cooling electromagnetic valves 31 are not simultaneously opened. Therefore, it is possible to prevent the refrigerant from flowing vigorously into the first connection pipe 6. Thereafter, it is determined whether or not there is a closed cooling electromagnetic valve 31 in the indoor unit that has a cooling request (step ST7). If there is a cooling electromagnetic valve 31 that is closed (Yes in step ST7), the process returns to step ST3. On the other hand, if there is no closed cooling electromagnetic valve 31 (No in step ST7), the control ends.

Here, in the first embodiment, not only the indoor unit B but also the indoor unit C requests cooling. For this reason, in Step ST7, there is a cooling electromagnetic valve 31 that is closed, and the process returns to Step ST3. And still the pressure P of the refrigerant is not less than the pressure threshold _{P 0,} flow of operation proceeds to step ST4. Here, for example, the second cooling electromagnetic valve 31b connected to the indoor unit C is selected. Then, it is confirmed whether the opening time threshold has elapsed since the opening of the second cooling electromagnetic valve 31b connected to the indoor unit B which is another branch (step ST5). The second cooling electromagnetic valve 31b connected to the selected indoor unit C is opened (step ST6).

Since the second cooling electromagnetic valve 31b connected to the indoor unit D is closed, the process returns to step ST3 again in step ST7. And still the pressure P of the refrigerant is not less than the pressure threshold _{P 0,} flow of operation proceeds to step ST4. Here, the second cooling electromagnetic valve 31b connected to the indoor unit D is selected. Then, it is confirmed whether or not the opening time threshold has elapsed since the opening of the second cooling electromagnetic valve 31b connected to the indoor unit D that was closed immediately before (step ST5), and when the opening time threshold has elapsed, The second cooling electromagnetic valve 31b connected to the selected indoor unit D is opened (step ST6). In step ST7, since the cooling electromagnetic valve 31 is not present, the control ends.

  According to the first embodiment, when it is determined that the refrigerant flowing through the second flow control device 13 or the third flow control device 15 generates a flow sound during the defrosting operation, the heating solenoid valve 30 and the cooling The electromagnetic valve 31 is opened sequentially. As a result, the amount of refrigerant flowing through the second flow control device 13 or the third flow control device 15 is reduced, so that the refrigerant flowing through the second flow control device 13 or the third flow control device 15 flows. Is suppressed. Therefore, the quietness of the air conditioner 100 is improved. Moreover, since quietness improves, the freedom degree of the installation place of the relay machine E increases.

  Moreover, the gas state detection part 80 which detects the state of the refrigerant | coolant which flows into gas branch pipe 6b, 6c, 6d is further provided, and the judgment means 72 is the gas state detection part 80, when a refrigerant | coolant distribute | circulates to the solenoid valve 30 for heating. Based on the state of the refrigerant detected by the above, the refrigerant flowing through the heating solenoid valve 30 has a function of determining whether or not it generates a flow noise. The timing control means 73 opens the heating solenoid valve 30 when the judgment means 72 determines that the refrigerant flowing through the heating solenoid valve 30 does not generate a flow noise, and when the time threshold has elapsed, The valve control means 71 is controlled so that the electromagnetic valve 31 is opened. The cooling electromagnetic valves 31 are a plurality of cooling electromagnetic valves 31 connected in parallel to each other, and the timing control means 73 determines that the refrigerant flowing into the heating electromagnetic valve 30 by the determination means 72 does not generate a flow sound. If it is determined, the heating electromagnetic valve 30 is opened, and when the time threshold value has elapsed, the valve control means 71 is controlled so as to open the plurality of cooling electromagnetic valves 31. Thereby, in the 2nd flow control device 13, the 3rd flow control device 15, and the solenoid valve 30 for heating, generation | occurrence | production of a flow sound can be suppressed.

  The timing control means 73 closes the heating solenoid valve 30 and opens the cooling solenoid valve 31 when the judgment means 72 determines that the refrigerant flowing through the heating solenoid valve 30 generates a flow noise, and the time threshold value is When the time has elapsed, the valve control means 71 is controlled to open the heating electromagnetic valve 30. The timing control means 73 controls the valve control means 71 so that the heating electromagnetic valves 30 connected to the gas branch pipes 6b, 6c, 6d are sequentially opened. Thereby, the refrigerant | coolant which flows into the solenoid valve 30 for heating and the solenoid valve 31 for cooling can be equalized. Therefore, the flow noise of the refrigerant can be suppressed.

  The timing control unit 73 opens the heating electromagnetic valve 30 and closes the cooling electromagnetic valve 31 when the determination unit 72 determines that the refrigerant flowing in the heating electromagnetic valve 30 generates a flow noise. When the time has elapsed, the valve control means 71 is controlled so as to open the cooling electromagnetic valve 31. The cooling electromagnetic valve 31 is a plurality of cooling electromagnetic valves 31 connected in parallel to each other, and the timing control means 73 determines that the refrigerant flowing through the heating electromagnetic valve 30 generates a flow sound by the determination means 72. If so, the heating solenoid valve 30 is opened and one of the cooling solenoid valves 31 is opened. When the time threshold value has elapsed, one of the closed cooling solenoid valves 31 is opened. The valve control means 71 is controlled. The valve control means 71 controls the valve control means 71 to sequentially open the cooling electromagnetic valves 31 connected to the gas branch pipes 6b, 6c, 6d. Thereby, the refrigerant | coolant which flows into the solenoid valve 30 for heating and the solenoid valve 31 for cooling can be equalized. Therefore, the flow noise of the refrigerant can be suppressed.

  Further, the timing control means 73 controls the valve control means 71 to open one of the plurality of cooling electromagnetic valves 31 when the indoor units B, C, D are switched from the heating operation to the cooling operation, Further, when it is determined that the flow noise of the refrigerant is generated, the valve control means 71 is controlled so as to open one of the closed electromagnetic valves 31 for cooling. In this way, since the plurality of cooling electromagnetic valves 31 are sequentially opened, the flow noise of the refrigerant can be reduced without using an orifice. Therefore, it is possible to improve the blocking function against refrigerant leakage and reduce the flow noise of the refrigerant.

  FIG. 12 is a circuit diagram showing a conventional air conditioner 200. As shown in FIG. 12, in the conventional air conditioner 200, the first branching section 110 includes a first cooling electromagnetic valve a, a second cooling electromagnetic valve c, an orifice d, and a heating electromagnetic valve b. Have. In the conventional air conditioner 200, when switching from the heating operation to the cooling operation, the refrigerant flows stepwise in the order of the orifice d, the first cooling electromagnetic valve a, and the second cooling electromagnetic valve c. As a result, the flow noise of the refrigerant is reduced. However, the orifice d attempts to reduce the refrigerant flow noise by equalizing the high-pressure side pipe and the low-pressure side pipe by bypassing the high pressure and the low pressure. Therefore, in the orifice d, the refrigerant supplied to the indoor unit during the heating operation is bypassed, so that the blocking function is bad.

  On the other hand, in the first embodiment, when the valve control means 71 opens one of the plurality of cooling electromagnetic valves 31, and the timing control means 73 determines that the refrigerant flow noise is generated, The valve control means 71 is controlled so as to open one of the closed electromagnetic valves 31 for cooling. For this reason, the flow noise of the refrigerant can be reduced without using an orifice. Therefore, it is possible to improve the blocking function against refrigerant leakage and reduce the flow noise of the refrigerant.

  Further, the valve control means 71 has a function of making the opening degree of the first flow control device 9 constant when the indoor units B, C, and D are switched from the heating operation to the cooling operation. Thereby, the first connecting pipe 6 and the second connecting pipe 7 are equalized. Accordingly, the refrigerant is prevented from flowing vigorously.

  Further, the timing control means 73 is configured to open one of the closed cooling electromagnetic valves 31 when the opening time threshold has elapsed after one of the closed cooling electromagnetic valves 31 is opened. The control means 71 is controlled. Accordingly, the refrigerant is prevented from flowing vigorously. For this reason, the flow noise of the refrigerant can be further reduced.

  Furthermore, the gas state detection unit 80 includes a merged pressure detection sensor 56 that detects the pressure of the refrigerant flowing through the portion where the liquid branch pipes 7b, 7c, and 7d and the first connection pipe 6 are connected, and a gas-liquid separation. A liquid outflow pressure detection sensor 25 for detecting the pressure of the refrigerant on the liquid outflow side of the apparatus 12, and the judging means 72 is a pressure difference of the refrigerant detected by the combined pressure detection sensor 56 and the liquid outflow pressure detection sensor 25. Is equal to or greater than the threshold value, it is determined that refrigerant flow noise is generated. Thereby, the pressure of the 1st connection piping 6 can be optimized. Therefore, the flow noise of the refrigerant can be further reduced.

(First modification)
FIG. 13 is a flowchart showing the operation of the air-conditioning apparatus 100 according to the first modification example of Embodiment 1 of the present invention. Next, a first modification of the first embodiment will be described. In the first modified example, the operation in step ST3 in FIG. 10 is different from that in the first embodiment, and the determination unit 72 determines the difference between one pressure of the cooling electromagnetic valve 31 and the other pressure of the cooling electromagnetic valve 31. Based on the above, it is determined whether or not the flow noise of the refrigerant is generated.

As shown in FIG. 13, the judgment means 72 causes the pressure of one of the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b and the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve. It is determined whether or not the difference ΔPa between 31 b and the other pressure is equal to or greater than the pressure difference threshold value ΔP ₀ (step ST41). Specifically, the determination unit 72 determines that the difference ΔPa between the refrigerant pressure detected by the merging pressure detection sensor 56 and the refrigerant pressure corresponding to the refrigerant temperature detected by the gas pipe temperature detection sensor 53 is a pressure. When the difference threshold value ΔP is equal to or greater than _0, it is determined that a refrigerant flow noise is generated. That is, the pressure of one of the first cooling electromagnetic valve 31 a and the second cooling electromagnetic valve 31 b is detected by the merged pressure detection sensor 56. The other pressure of the first cooling electromagnetic valve 31 a and the second cooling electromagnetic valve 31 b is calculated based on the saturation temperature detected by the gas pipe temperature detection sensor 53. As shown in FIG. 10, when the pressure difference ΔP is less than the pressure difference threshold ΔP ₀ (No in step ST3), the normal operation is resumed. On the other hand, when the pressure difference ΔP is equal to or greater than the pressure difference threshold ΔP ₀ (Yes in step ST3), the process proceeds to step ST4.

  Thus, in the first modification, the gas state detection unit 80 detects the pressure of the refrigerant flowing through the portion where the liquid branch pipes 7b, 7c, 7d and the first connection pipe 6 are connected. The sensor 56 and a gas pipe temperature detection sensor 53 that detects the temperature of the refrigerant flowing through the gas branch pipes 6b, 6c, and 6d, and the determination means 72 detects the refrigerant pressure detected by the merged pressure detection sensor 56. When the difference between the refrigerant pressure and the refrigerant pressure corresponding to the refrigerant temperature detected by the gas pipe temperature detection sensor 53 is equal to or greater than the pressure difference threshold, it is determined that the refrigerant flow noise is generated. This first modification also has the same effect as that of the first embodiment.

(Second modification)
FIG. 14 is a flowchart showing the operation of the air-conditioning apparatus 100 according to the second modification of the first embodiment of the present invention. Next, a second modification of the first embodiment will be described. In the second modified example, the operation in step ST3 in FIG. 10 is different from that in the first embodiment, and the determination unit 72 sets the subcool value on the outlet side of the indoor heat exchanger 5 of the indoor unit that is performing the heating operation. Based on this, it is determined whether or not a refrigerant flow noise is generated.

As shown in FIG. 14, the determination means 72, subcooled value SCa of the outlet side of the indoor heat exchanger 5 which indoor unit has that heating operation, whether it is subcooled threshold SC ₀ or more is determined (Step ST51). The subcool value SCa is calculated based on the saturation temperature of the indoor unit during the heating operation and the refrigerant temperature detected by the liquid pipe temperature detection sensor 54. The saturation temperature of the indoor unit during the heating operation is calculated based on the pressure detected by the liquid outflow pressure detection sensor 25. As shown in FIG. 10, for subcooling value SCa is of less than subcooling threshold SC ₀ (No in step ST3), a small liquid refrigerant, it is determined that flow noise of the refrigerant is not generated, the flow returns to normal operation. On the other hand, if the subcooling value SCa is more subcooling threshold SC ₀ (Yes in step ST3), because there are many liquid refrigerant, it is determined that flow noise of the refrigerant is generated, before proceeding to a step ST4.

  Thus, in the second modification, the relay E has the inflow side connected to the second connection pipe 7, the gas outflow side connected to the heating solenoid valve 30, and the liquid outflow side liquid branch pipes 7b, 7c, 7d. The gas-liquid separator 12 is further connected to the gas-liquid separator 12 to separate the gas refrigerant and the liquid refrigerant, and the gas state detection unit 80 detects the pressure of the refrigerant on the liquid outlet side of the gas-liquid separator 12. A sensor 25 and a liquid pipe temperature detection sensor 54 for detecting the temperature of the refrigerant flowing through the liquid branch pipes 7b, 7c, and 7d, and the judging means 72 is configured to detect the refrigerant detected by the liquid outflow pressure detection sensor 25. When the subcool value on the outlet side of the indoor heat exchanger 5 calculated based on the refrigerant temperature corresponding to the pressure and the refrigerant temperature detected by the liquid pipe temperature detection sensor 54 is equal to or greater than the subcool threshold, It is determined that refrigerant flow noise is generated. It is intended to. This second modification also has the same effect as that of the first embodiment.

(Third Modification)
FIG. 15 is a flowchart showing the operation of the air-conditioning apparatus 100 according to the third modification of the first embodiment of the present invention. Next, a third modification of the first embodiment will be described. In the third modified example, the operation in step ST3 in FIG. 10 is different from that in the first embodiment, and the determination unit 72 is configured to stop the threshold value after the indoor heat exchanger 5 of the indoor unit that is performing the heating operation is stopped. It is determined whether or not a refrigerant flow noise is generated depending on whether or not time has elapsed.

As shown in FIG. 15, whether or not the elapsed time Ta after the indoor side heat exchanger 5 of the indoor unit that is performing the heating operation is equal to or less than the threshold elapsed time T ₀ is determined by the determining unit 72. Judgment is made (step ST61). As shown in FIG. 10, when the elapsed time Ta is elapsed time T ₀ or larger than the threshold (No in step ST3), the difference between the pressure and the pressure in the second connecting pipe 7 of the first connection pipe 6 is reduced Then, it is determined that no refrigerant flow noise is generated, and the normal operation is resumed. On the other hand, when the elapsed time Ta is less than the threshold value the elapsed time T ₀ (step ST3 Yes), it therefore, the refrigerant remains difference between the pressure of the pressure and the second connecting pipe 7 of the first connection pipe 6 is greater It is determined that a flowing sound is generated, and the process proceeds to step ST4.

  Thus, in the third modified example, the determination unit 72 is configured until the stop threshold time elapses after the indoor heat exchanger 5 of the indoor units B, C, and D that are performing the heating operation is stopped. It is determined that the flow noise of the refrigerant is generated. In the third modification, the same effect as in the first embodiment is obtained.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 flow-path switching valve, 3 heat source side heat exchange unit, 4 accumulator, 5 indoor side heat exchanger, 6 1st connection piping, 6b, 6c, 6d gas branch pipe, 7 2nd connection piping, 7b, 7c, 7d Liquid branch pipe, 8 Heat exchange section, 9 First flow control device, 10 First branch section, 11 Second branch section, 12 Gas-liquid separator, 13 Second flow control apparatus, 14 1st bypass piping, 15 3rd flow control device, 16 2nd heat exchange part, 18 discharge pressure detection sensor, 19 1st heat exchange part, 20 heat source side blower, 25 liquid outflow pressure detection sensor, 26 Downstream liquid outflow pressure detection sensor, 30 heating solenoid valve, 31 cooling solenoid valve, 31a first cooling solenoid valve, 31b second cooling solenoid valve, 32 third check valve, 33 fourth Check valve, 34 fifth check valve, 35 sixth check valve Valve, 40 heat source side flow path adjustment unit, 41 first heat source side heat exchanger, 42 second heat source side heat exchanger, 43 heat source side bypass, 44 first electromagnetic open / close valve, 45 second electromagnetic open / close Valve, 46 third electromagnetic on-off valve, 47 fourth electromagnetic on-off valve, 48 fifth electromagnetic on-off valve, 50b first check valve, 50c first check valve, 50d first check valve, 51 Second bypass piping, 52b Second check valve, 52c Second check valve, 52d Second check valve, 53 Gas pipe temperature detection sensor, 54 Liquid pipe temperature detection sensor, 56 Combined pressure detection sensor , 70 control unit, 71 valve control unit, 72 determination unit, 73 timing control unit, 80 gas state detection unit, 81 liquid state detection unit, 100 air conditioner, 110 first branching unit, 111 second branching unit, 112 Gas-liquid separator, 113 No. 2 flow control device, 115 third flow control device, 116 second heat exchange unit, 119 first heat exchange unit, 200 air conditioner, A heat source unit, B indoor unit, C indoor unit, D indoor unit , E repeater.

Claims (13)

A heat source machine having a compressor, a flow path switching valve and a heat source side heat exchanger;
A plurality of indoor units each having a first flow control device and an indoor heat exchanger, and performing a cooling operation or a heating operation;
A refrigerant that is connected to the heat source unit by a first connection pipe and a second connection pipe, is connected to the plurality of indoor units by a plurality of gas branch pipes and a plurality of liquid branch pipes, and is supplied from the heat source unit. A repeater that distributes the plurality of indoor units;
A control unit for controlling the operation of the repeater,
The repeater is
A liquid state detector that detects the state of the refrigerant flowing between the liquid branch pipe and the second connection pipe;
The refrigerant flowing in is separated into a gas refrigerant and a liquid refrigerant, the inflow side is connected to the second connection pipe, the gas outflow side is connected to the gas branch pipe, and the liquid outflow side is connected to the liquid branch pipe and the liquid refrigerant. A gas-liquid separator connected to the first connection pipe;
A second flow rate control device that is provided on the liquid outflow side of the gas-liquid separator, is closed during heating operation, is opened during cooling operation, and adjusts the flow rate of refrigerant;
A third flow control device that is provided downstream of the second flow control device and adjusts the flow rate of the refrigerant;
A plurality of cooling solenoid valves, one connected to the gas branch pipe, the other connected to the first connection pipe, opened during cooling operation, and closed during heating operation;
One is connected to the gas branch pipe, the other is connected to the gas outflow side of the gas-liquid separator, and has a heating solenoid valve that is opened during heating operation and closed during cooling operation,
The controller is
When the heat source device is switched from heating operation to defrosting operation, valve control means for switching the flow path switching valve, closing the heating electromagnetic valve, and opening the second flow control device;
When the refrigerant flows through the second flow control device, the refrigerant flowing through the second flow control device or the third flow control device is based on the state of the refrigerant detected by the liquid state detection unit. A judging means for judging whether or not to generate a flowing sound;
When the determination means determines that the refrigerant flowing through the second flow control device or the third flow control device generates a flow noise, the heating solenoid valve and the cooling solenoid valve are sequentially opened. have a, a timing control means for controlling said valve control means,
The timing control means includes
An air conditioner that controls the valve control means so as to first open a cooling solenoid valve having a small Cv value among the plurality of cooling solenoid valves . A gas state detection unit for detecting a state of the refrigerant flowing in the gas branch pipe;
The determination means includes
A function of determining whether or not the refrigerant flowing through the heating solenoid valve generates a flow sound based on the state of the refrigerant detected by the gas state detection unit when the refrigerant flows through the heating solenoid valve The air conditioner according to claim 1. The timing control means includes
When it is determined by the determining means that the refrigerant flowing through the heating solenoid valve does not generate a flow noise, the heating solenoid valve is opened, and when the time threshold has elapsed, the cooling solenoid valve is opened. The air conditioning apparatus according to claim 2, wherein the valve control unit is controlled. The cooling solenoid valves are a plurality of cooling solenoid valves connected in parallel to each other,
The timing control means includes
When it is determined by the determining means that the refrigerant flowing through the heating solenoid valve does not generate a flow noise, the heating solenoid valve is opened, and when the time threshold has elapsed, the plurality of cooling solenoid valves are opened. The air conditioning apparatus according to claim 3, wherein the valve control means is controlled as follows. The timing control means includes
When it is determined by the determination means that the refrigerant flowing through the heating solenoid valve generates a flow noise, the heating solenoid valve is closed and the cooling solenoid valve is opened. The air conditioning apparatus according to claim 2, wherein the valve control means is controlled so as to open a solenoid valve for operation. The timing control means includes
The air conditioner according to claim 5, wherein the valve control means is controlled so as to sequentially open the heating solenoid valves connected to the gas branch pipes. The timing control means includes
When it is determined by the determining means that the refrigerant flowing through the heating solenoid valve generates a flow noise, the heating solenoid valve is opened and the cooling solenoid valve is closed. The air conditioning apparatus according to claim 2, wherein the valve control means is controlled so as to open a solenoid valve for operation. The cooling solenoid valves are a plurality of cooling solenoid valves connected in parallel to each other,
The timing control means includes
When it is determined by the determining means that the refrigerant flowing through the heating solenoid valve generates a flow noise, the heating solenoid valve is opened and one of the cooling solenoid valves is opened, and a time threshold has elapsed. The air conditioning apparatus according to claim 2, wherein the valve control means is controlled to open one of the closed solenoid valves for cooling. The valve control means includes
The air conditioner according to claim 7 or 8, wherein the valve control means is controlled so as to sequentially open the cooling electromagnetic valves connected to the gas branch pipes. The gas state detector
A combined pressure detection sensor for detecting a pressure of a refrigerant flowing through a portion where the liquid branch pipe and the first connection pipe are connected;
A liquid outflow pressure detection sensor for detecting the pressure of the refrigerant on the liquid outflow side of the gas-liquid separator,
The determination means includes
The refrigerant flowing through the cooling solenoid valve is determined to generate a flow noise when a pressure difference between the refrigerant detected by the merging pressure detection sensor and the liquid outflow pressure detection sensor is greater than or equal to a threshold value. The air conditioning apparatus according to any one of the above. The gas state detector
A liquid outflow pressure detection sensor for detecting the pressure of the refrigerant on the liquid outflow side of the gas-liquid separator;
A liquid pipe temperature detection sensor for detecting the temperature of the refrigerant flowing through the liquid branch pipe,
The determination means includes
The outlet side of the indoor heat exchanger calculated based on the refrigerant temperature corresponding to the refrigerant pressure detected by the liquid outflow pressure detection sensor and the refrigerant temperature detected by the liquid pipe temperature detection sensor The air conditioning apparatus according to any one of claims 2 to 10, wherein when the subcool value is equal to or greater than a subcool threshold, the refrigerant flowing through the cooling electromagnetic valve generates a flow sound. The gas state detector
A combined pressure detection sensor for detecting a pressure of a refrigerant flowing through a portion where the liquid branch pipe and the first connection pipe are connected;
A gas pipe temperature detection sensor for detecting the temperature of the refrigerant flowing through the gas branch pipe,
The determination means includes
When the difference between the refrigerant pressure detected by the merging pressure detection sensor and the refrigerant pressure corresponding to the refrigerant temperature detected by the gas pipe temperature detection sensor is equal to or greater than a pressure difference threshold, the cooling electromagnetic It is judged that the refrigerant | coolant which flows into a valve generate | occur | produces a flow sound. The air conditioning apparatus of any one of Claims 2-11. The determination means includes
It is determined that the refrigerant flowing through the cooling solenoid valve generates a flow noise until the stop threshold time elapses after the indoor heat exchanger of the indoor unit that is performing the heating operation is stopped. The air conditioning apparatus of any one of Claims 1-12.

Images