JP6644131B2 - Air conditioner - Google Patents

Description

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

In an air conditioner in which a heating operation or a cooling operation is individually performed in a plurality of indoor units, for example, hot heat, cold heat, or both hot and cold heat created in a heat source unit 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. 2. Description of the Related Art Conventionally, in an air conditioner such as a multi air conditioner for a building, a cooling operation or a heating operation is performed by circulating a refrigerant between an outdoor unit, which is a heat source unit disposed outdoors, and an indoor unit disposed indoors, for example. Is executed. Specifically, cooling or heating of the air-conditioned space is performed by air cooled by absorbing heat of the refrigerant or air heated by cooling of the refrigerant. As a refrigerant used in such an air conditioner, for example, an HFC-based refrigerant, that is, a hydrofluorocarbon-based refrigerant is often used. An air conditioner using carbon dioxide, that is, a natural refrigerant such as CO _2, has also been proposed.

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

  The air conditioner described in Patent Literature 1 switches between a refrigerant flowing into an indoor unit performing a heating operation and a refrigerant flowing from an indoor unit performing a cooling operation by using a three-way switching valve in a first branch portion. It is done in. In addition, each check valve constituting the second branch portion allows the flow of the refrigerant in one direction in accordance with the switching of the refrigerant in the first branch portion. Therefore, when the indoor unit performs the cooling operation, the first port of the three-way switching valve is closed, and the second and third ports are open. When the indoor unit performs the heating operation, the second port of the connection port is closed, and the first and third ports are open.

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

  When the indoor unit performs the 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 has a high pressure and a second pressure in the connection pipe on the first port side of the connection port of the three-way switching valve. The connection pipe at the mouth has a low pressure, and the connection pipe at the third mouth has a high pressure. In the heating operation, the refrigerant is controlled by the subcool amount on the outlet side of the indoor heat exchanger, and the high-temperature high-pressure gas state refrigerant flows through the first connection pipe on the indoor unit side. Here, a refrigerant in a high-temperature and high-pressure liquid state exists in the indoor heat exchanger and a connection pipe from the indoor heat exchanger to the first flow control device.

  Therefore, when the operation of the indoor unit is 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 flowing during the heating pass through the three-way switching valve and are in the first low-pressure state. Flows into the connection pipe. At this time, in the three-way switching valve, the flow noise of the refrigerant 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 and high-pressure liquid refrigerant increases.

  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 solenoid valve is used for heating, and the first solenoid valve and the third solenoid valve with the orifice function are used for cooling, When the operation is switched from the heating operation to the cooling operation, the refrigerant is caused to flow stepwise through the first solenoid valve and the third solenoid valve. This aims to reduce the flow noise of the high-temperature and high-pressure liquid refrigerant. In the air conditioner 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 on the flow control device, and reducing the opening diameter of the third solenoid valve. Trying to reduce. In addition, an air conditioner that uses an electromagnetic valve, particularly an electromagnetic opening / closing valve, and is made compact has been proposed. In this air conditioner, the second solenoid valve is used for heating, and the first solenoid valve, the third solenoid valve, and the orifice are used for cooling. Here, the orifice is intended to equalize the high-pressure side pipe and the low-pressure side pipe by bypassing the high pressure and the low pressure to reduce 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 caused to flow stepwise through the orifice, the third solenoid valve, and the first solenoid valve. This aims to reduce the flow noise of the high-temperature and high-pressure liquid refrigerant.

Japanese Patent No. 4350836 JP-A-09-042804

  However, the above-mentioned air conditioner requires three solenoid valves and orifices for one indoor unit. For this reason, three electromagnetic valves and orifices are required at the branching unit for each indoor unit. As described above, the orifice bypasses the pipe connected to the indoor unit and the pipe connected to the heat source unit, and from the viewpoint of refrigerant leakage, it is difficult to shut off to the indoor unit pipe side at each branch. Structure.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide an air conditioner that improves a function of shutting off refrigerant leakage and reduces flow noise of refrigerant.

An air conditioner according to the present invention includes a heat source unit having a compressor and a heat source side heat exchanger, and a plurality of indoor units having a first flow control device and an indoor side heat exchanger, and performing a cooling operation or a heating operation. And a plurality of refrigerants connected to the heat source unit by the first connection pipe and the second connection pipe, respectively connected to the plurality of indoor units by the plurality of gas branch pipes and the plurality of liquid branch pipes, and supplied from the heat source unit. A relay unit for distributing to the indoor units, a state detection unit for detecting the state of the refrigerant flowing in the gas branch pipe, and a control unit for controlling the operation of the relay unit, and one of the relay units is connected to the gas branch pipe. A plurality of cooling solenoid valves connected in parallel to each other, which are connected to each other and connected to the first connection pipe, opened during the cooling operation and closed during the heating operation, and one connected to the gas branch pipe; Is connected to the second connection pipe and is opened during the heating operation. The heating electromagnetic valve is closed during the cooling operation, and the control unit has a valve control unit that controls the opening and closing of the plurality of cooling electromagnetic valves, and when the refrigerant flows through the cooling electromagnetic valve, based on the state of the refrigerant detected by the state detection unit, a determination unit for determining whether the flow sound is generated, all the indoor switched to cooling operation when switching the indoor unit from the heating operation to the cooling operation Controlling the valve control means so as to open one of the plurality of solenoid valves for cooling having the smallest Cv value among the plurality of solenoid valves connected to the cooling device, and closing the valve when the judgment means judges that the flow noise of the refrigerant is generated. Timing control means for controlling the valve control means so as to open one of the cooled cooling electromagnetic valves, wherein the valve control means switches the first indoor unit from the heating operation to the cooling operation, The flow control device It has the ability to.

  According to the present invention, when the timing control unit switches the indoor unit from the heating operation to the cooling operation, the timing control unit controls the valve control unit to open one of the plurality of cooling electromagnetic valves, When it is determined that the flow noise is generated, the valve control means is controlled to open one of the closed cooling electromagnetic valves. As described above, since the plurality of cooling electromagnetic valves are opened in a stepwise manner, the flow noise of the refrigerant can be reduced without using an orifice. Therefore, the function of shutting off refrigerant leakage can be improved, and the flow noise of the refrigerant can be reduced.

FIG. 2 is a circuit diagram showing an air conditioner 100 according to Embodiment 1 of the present invention. FIG. 3 is a block diagram illustrating a control unit 70 of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. FIG. 3 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in a cooling only operation. FIG. 3 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in a heating only operation. FIG. 3 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in a cooling-main operation. FIG. 3 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in a heating main operation. 5 is a flowchart illustrating an operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. 5 is a flowchart illustrating an operation of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. It is a circuit diagram showing the conventional air conditioner 200. 5 is a flowchart illustrating an operation of the air-conditioning apparatus 100 according to the first modified example of Embodiment 1 of the present invention. 5 is a flowchart illustrating an operation of the air-conditioning apparatus 100 according to the second modification of Embodiment 1 of the present invention. It is a flow chart which shows operation of air conditioner 100 concerning a 3rd modification of Embodiment 1 of the present invention.

Embodiment 1 FIG.
Hereinafter, an embodiment of an air conditioner according to the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing an air conditioner 100 according to Embodiment 1 of the present invention. The air conditioner 100 will be described based on FIG. As shown in FIG. 1, the air conditioner 100 includes a heat source unit A, a plurality of indoor units B, C, D, a relay unit E, and a control unit 70. In the first embodiment, a case is described in which three indoor units B, C, and D are connected to one heat source unit A, but the number of heat source units A may be two or more. 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 with each other and have the same configuration. Each of the indoor units B, C, and D has a function of cooling or heating a space to be air-conditioned such as a room by using hot or cold heat supplied from the heat source unit A. The relay device E is provided between the heat source unit A and the indoor units B, C, and D, and has a function of switching the flow of the refrigerant supplied from the heat source unit A in response to a request from the indoor units B, C, and D. Have. Further, the air-conditioning apparatus 100 includes a state detection unit 80 that detects a state of the refrigerant. The state detector 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 liquid outflow pressure detection sensor 26, a combined pressure detection sensor 56, and a discharge pressure detection sensor 18. ing.

(Heat source A)
The heat source unit A is provided via a compressor 1 having a variable capacity, a flow path switching valve 2 for switching a refrigerant flow direction in the heat source apparatus A, a heat source side heat exchange unit 3 functioning as an evaporator or a condenser, and a flow path switching valve 2. The compressor 1 includes an accumulator 4 connected to the suction side of the compressor 1 and a heat source side flow path adjustment unit 40 for restricting the flow direction of the refrigerant. The heat source unit A has a function of supplying hot or cold heat to the indoor units B, C, and D. In addition, although the case where the flow path switching valve 2 is a four-way valve is illustrated, 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 solenoid on-off valve 44, a second solenoid 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 with each other. The heat source side bypass 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 exchanged.

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

  The heat source side flow path adjustment unit 40 has 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 controls the flow of the refrigerant from the heat source side heat exchange unit 3 to the second connection pipe 7. Allow. The fourth check valve 33 is provided on a pipe connecting the flow path switching valve 2 of the heat source device A and the first connection pipe 6, and serves as a refrigerant for the refrigerant flowing 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 that connects the flow path switching valve 2 of the heat source device A and the second connection pipe 7, and serves as a refrigerant for flowing from the flow path switching valve 2 to the second connection pipe 7. Allow distribution. The sixth check valve 35 is provided on a pipe connecting the heat source side heat exchange unit 3 and the first connection pipe 6, and controls the flow of the refrigerant from the first connection pipe 6 to the heat source side heat exchange unit 3. Allow.

  Further, the heat source device 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 a discharge pressure of the compressor 1. The heat-source-side blower 20 changes the amount of air blown to the heat-source-side heat exchange unit 3 to control the heat exchange capacity.

(Indoor units B, C, D)
Each of the indoor units B, C, and D includes an indoor heat exchanger 5 and a first flow control device 9 functioning as a condenser or an evaporator, and air-conditions indoors or the like by hot or cold heat supplied from the heat source unit A. It has a function of cooling or heating the target space. The first flow control device 9 is controlled by the amount of superheat at the outlet side of the indoor heat exchanger 5 during cooling. Further, the first flow control device 9 is controlled by the subcool amount on the outlet side of the indoor heat exchanger 5 during 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 connecting the indoor heat exchanger 5 and the relay E. It detects the temperature of the flowing refrigerant. The liquid pipe temperature detection sensor 54 is provided between the indoor heat exchanger 5 and the first flow control device 9, and connects the indoor heat exchanger 5 to the first flow control device 9. The temperature of the refrigerant flowing through the branch pipes 7b, 7c, 7d is detected.

(Repeater E)
The repeater E includes a first branch 10, a second flow controller 13, a second branch 11, a gas-liquid separator 12, a heat exchanger 8, and a third flow controller 15. The relay unit E is interposed between the heat source unit A and the indoor units B, C, and 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, and D, and It has a function of distributing the refrigerant supplied from the unit A to the plurality of indoor units B, C, and D.

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

  One of the first branch portions 10 is connected to one of the gas branch pipes 6b, 6c, and 6d, and the other is connected to the first connection pipe 6 and the second connection pipe 7. The flow direction of the refrigerant during the heating operation is different. The first branch unit 10 includes a first cooling electromagnetic valve 31a, a second cooling electromagnetic valve 31b, and a heating electromagnetic valve 30. The first cooling solenoid valve 31a and the second cooling solenoid valve 31b are connected in parallel with each other, one of them is connected to the gas branch pipes 6b, 6c, 6d, and the other is connected to the first branch. It is connected to the connection pipe 6 and is opened during the cooling operation and closed during the heating operation.

  One of the heating electromagnetic 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 solenoid valve 31a and the second cooling solenoid valve 31b connected to the indoor units B, C, and D may be collectively referred to as a cooling solenoid valve 31. The number of cooling electromagnetic valves 31 is not limited to two, but may be three or more. The first cooling solenoid valve 31a and the second cooling solenoid valve 31b may have the same or different Cv values. Further, the cooling solenoid 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, 7d, 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 changed. The flow direction of the refrigerant during the heating operation is different. The second branch portion 11 has first check valves 50b, 50c, 50d and second check valves 52b, 52c, 52d.

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

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

  The gas-liquid separator 12 separates a gaseous refrigerant from a liquid refrigerant, and has an inflow side connected to the second connection pipe 7, a gas outflow side connected to the first branch portion 10, The outflow side is connected to the second branch portion 11.

  The heat exchange section 8 includes a first heat exchange section 19 and a second heat exchange section 16. The second flow control device 13 is constituted by, for example, an openable and closable electric expansion valve. Here, the gas-liquid separation device 12 and the second branch portion 11 are connected via a first heat exchange unit 19, a second flow control device 13, and a second heat exchange unit 16. Further, the second branch part 11 and the first connection pipe 6 are connected by a first bypass pipe 14. The third flow control device 15 is provided in the first bypass pipe 14, and is configured by, for example, an openable and closable electric expansion valve. Here, the second branch portion 11 and the first connection pipe 6 are connected via a third flow control device 15, a second heat exchange portion 16, and a first heat exchange portion 19.

  That is, the first heat exchange section 19 heats the second connection pipe 7 upstream of the second flow control device 13 and the first bypass pipe 14 downstream of the second heat exchange section 16. To replace. In addition, the second heat exchange unit 16 heats the second connection pipe 7 downstream of the second flow control device 13 and the first bypass pipe 14 downstream of the third flow control device 15. To replace.

  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 control device 13 in the second connection pipe 7, and the second The upstream side of the heat exchange section 16 is connected by a second bypass pipe 51. Then, the pipe connected to the liquid branch pipes 7b, 7c, 7d in the second bypass pipe 51 and the pipe connected to the second connection pipe 7 in the second bypass pipe 51 merge on the way.

  The second check valves 52b, 52c, and 52d are connected to the pipes connected to the liquid branch pipes 7b, 7c, and 7d in the second bypass pipe 51 and the second connection pipe 7 in the second bypass pipe 51, respectively. Is provided upstream of a portion where the pipes connected to the pipes merge. 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. A refrigerant flow path is formed, and a second flow path is provided from the first flow 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 reaching the connection pipe 7 constitutes a second refrigerant flow path.

  Further, the repeater E is provided with a liquid outflow pressure detection sensor 25, a downstream liquid outflow pressure detection sensor 26, and a merged 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 provided on the liquid outflow side of the gas-liquid separation device 12. This is to detect the pressure. The downstream liquid outflow pressure detection sensor 26 is provided between the second flow control device 13 and the second heat exchange unit 16 in the second connection pipe 7, and the second flow control device 13 and the second It detects the pressure of the refrigerant between the second heat exchange unit 16 and the second heat exchange unit 16. That is, the downstream-side 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, and 7d join. The junction pressure detection sensor 56 is provided at a portion where the first connection pipe 6 and the first bypass pipe 14 are connected, and connects the liquid branch pipes 7b, 7c, 7d to the first connection pipe 6. This is to detect the pressure of the refrigerant flowing through the section.

(Refrigerant)
In the air-conditioning apparatus 100, the inside of the pipe is filled with a refrigerant. Refrigerants include, for example, natural refrigerants such as carbon dioxide (CO ₂ ), hydrocarbons, helium, etc .; chlorine-free refrigerants such as HFC410A, HFC407C, HFC404A; Etc. are used. The HFC 407C 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. Further, the inside of the pipe of the air conditioner 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 conditioner 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 liquid outflow pressure detection sensor 26, a merged pressure detection sensor 56, and a discharge pressure detection sensor. Based on the detection information received from 18 and an instruction from a remote controller (not shown), the drive frequency of the compressor 1 and the blower (not shown) provided in the heat source side blower 20 and the indoor side heat exchanger 5 are provided. Number of rotations, 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 and closing of the first cooling solenoid valve 31a, the second cooling solenoid valve 31b, and the heating solenoid valve 30, the first flow control device 9, the second flow control device 13, the third flow control device 15 And the like.

  The control unit 70 may be mounted on any one 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. When the air-conditioning apparatus 100 includes a plurality of control units 70, the air-conditioning apparatuses 100 are wirelessly or wiredly connected to each other.

  FIG. 2 is a block diagram illustrating control unit 70 of air-conditioning apparatus 100 according to Embodiment 1 of the present invention. As shown in FIG. 2, the control unit 70 includes a valve control unit 71, a determination unit 72, and a timing control unit 73. The valve control means 71 controls opening and closing of the plurality of cooling electromagnetic valves 31. Further, the valve control means 71 has a function of keeping the opening of the first flow control device 9 constant when the indoor units B, C, and D switch 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 judging means 72 judges whether or not a flowing noise is generated based on the state of the refrigerant detected by the state detecting section 80 when the refrigerant flows through the cooling electromagnetic valve 31. Specifically, the determination means 72 uses the pressure of the refrigerant detected by the downstream liquid outflow pressure detection sensor 26 and the merged pressure detection sensor 56, and when the pressure difference before and after the cooling solenoid valve 31 is equal to or greater than a threshold value, It is determined that the flow noise of the refrigerant is generated. The case where the state of the refrigerant flowing into the cooling electromagnetic valve 31 is determined based on the detection information of the merged pressure detection sensor 56 has been described as an example. However, the present invention is not limited to this. Information from the detection means may be used.

  For example, the state of the refrigerant flowing into the cooling electromagnetic valve 31 is estimated by predicting the differential pressure value at the entrance and exit of the cooling electromagnetic valve 31 based on information from the merged pressure detection sensor 56 and the gas pipe temperature detection sensor 53. You may make it determine. Further, the state of the refrigerant flowing into the cooling electromagnetic valve 31 may be determined based on the outlet subcool value of the indoor heat exchanger 5 performing the heating operation before switching to the cooling operation. Furthermore, the state of the refrigerant flowing into the cooling electromagnetic valve 31 may be determined by predicting the state of the refrigerant of the stopped indoor unit from the elapsed time from the stop of the heating. Furthermore, the state of the refrigerant flowing into the fourth flow control device 55 may be determined by combining these.

  The timing control unit 73 controls the valve control unit 71 to open one of the plurality of cooling electromagnetic valves 31 when the indoor units B, C, and D switch from the heating operation to the cooling operation, and When the determination means 72 determines that the flow noise of the refrigerant is generated, the valve control means 71 is controlled so as to open one of the closed cooling electromagnetic valves 31. Further, the timing control means 73 is configured to open one of the closed cooling electromagnetic valves 31 when the opening time threshold value has elapsed since one of the closed cooling electromagnetic valves 31 was opened. The control means 71 may be controlled. For example, the timing control unit 73 opens the second cooling electromagnetic valve 31b when the opening time threshold has elapsed since the first cooling electromagnetic valve 31a was opened by the valve control unit 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 and the second cooling electromagnetic valve 31b connected to the indoor unit B and the indoor unit C 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 unit 73 may control the valve control unit 71 to open from the cooling electromagnetic valve 31 connected to, for example, the indoor unit B having the lower address. Does not matter.

  When the first cooling electromagnetic valve 31a connected to the indoor unit B is opened by the valve control means 71, the timing control means 73 sets the second cooling electromagnetic valve 31b connected to the indoor unit B to May be controlled to open the indoor unit C, the valve control unit 71 may be controlled 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 so as to open the second cooling electromagnetic valve 31b connected to the second cooling electromagnetic valve 31b. 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 opened by the valve control means 71 is connected, but also Alternatively, the valve control means 71 may be controlled to open the cooling electromagnetic valve 31 connected to another indoor unit C.

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

  Next, the operation of the air conditioner 100 will be described. The air-conditioning apparatus 100 has, as operation modes, a cooling only operation, a heating only operation, a cooling main operation, and a heating main operation. The cooling only operation is a mode in which all of the indoor units B, C, and D perform the cooling operation. The heating only 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 cooling operation capacity is larger than the heating operation capacity in the simultaneous cooling and heating operation. The heating main operation is a mode in which the capacity of the heating operation is larger than the capacity of the cooling operation in the simultaneous cooling and heating operation.

(Cooling operation)
FIG. 3 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in a cooling only operation. First, the cooling only operation will be described. In the air-conditioning apparatus 100, all of the indoor units B, C, and D perform 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 airflow in the heat-source-side heat exchange unit 3. It is heat exchanged and condensed and liquefied. The refrigerant then flows in the order of the third check valve 32, the second connection pipe 7, the gas-liquid separator 12, the second flow controller 13, and the second branch 11, the liquid branch pipe. After passing through 7b, 7c and 7d, they flow into the indoor units B, C and D.

  Then, the refrigerant flowing into the indoor units B, C, and D is reduced to a low pressure by the first flow control device 9 controlled by the amount of superheat on the outlet side of the indoor heat exchanger 5. The depressurized 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 gaseous refrigerant is supplied to the gas branch pipes 6b, 6c, 6d, the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b of the first branch portion 10, and the first connection pipe. 6. The refrigerant is 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 the heating electromagnetic valves 30 are closed. Each of the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b is open. 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, part of the refrigerant that has passed through the second flow control device 13 enters the first bypass pipe 14. Then, the refrigerant is decompressed to a low pressure by the third flow control device 15, and then 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. It exchanges heat with the previous refrigerant and evaporates. Further, the first heat exchange section 19 performs heat exchange with the refrigerant before flowing into the second flow control device 13 to evaporate. 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 device A.

  On the other hand, in the first heat exchange unit 19 and the second heat exchange unit 16, heat exchange is performed with the refrigerant that flows into the first bypass pipe 14 and is reduced to a low pressure by the third flow control device 15. The refrigerant that has been cooled down and is sufficiently subcooled flows through the first check valves 50b, 50c, and 50d of the second branch portion 11 into the indoor units B, C, and D that are about to be cooled. Here, the control unit 70 controls the capacity and the heat source side of the compressor 1 so that the evaporation temperature of the indoor units B, C, and D and the condensation temperature of the heat source side heat exchange unit 3 become the predetermined target temperature. The blowing amount of the blower 20 is adjusted. Therefore, 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 a 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 of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in a heating only operation. Next, the heating only operation will be described. In the air-conditioning apparatus 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 air flows into the indoor units B, C and D in the order of the heating electromagnetic valve 30 and the gas branch pipes 6b, 6c and 6d in the first branch portion 10. The refrigerant flowing into the indoor units B, C, and D exchanges heat with indoor air and condenses and liquefies. At this time, the room is heated. The refrigerant in this state passes through the first flow control device 9 controlled by the subcool amount on the outlet side of each indoor heat exchanger 5.

  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, and 7d, and joins after passing through the second check valves 52b, 52c, and 52d. The refrigerant that has merged in 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 the third flow control device 15 Pass. Further, the refrigerant is reduced to a low-pressure two-phase gas-liquid phase by the first flow control device 9 and the third flow control device 15.

  The refrigerant decompressed to a low pressure passes through the first connection pipe 6 and passes through the sixth check valve 35 of the heat source unit A, flows into the heat source side heat exchange unit 3, and has a variable air flow rate heat source side. The heat is exchanged with the air blown by the blower 20 to evaporate. The refrigerant that has been evaporated to a gaseous state is sucked into the compressor 1 via the flow path switching valve 2 and the accumulator 4.

  In the heating only operation, all the heating solenoid valves 30 are open. Further, both the first cooling solenoid valve 31a and the second cooling solenoid valve 31b are closed.

  In this circulation cycle, the first connection pipe 6 has a low pressure and the second connection pipe 7 has 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, 7d have a higher pressure than the second connection pipe 7, the refrigerant does not pass through the first check valves 50b, 50c, 50d. Here, the control unit 70 controls the capacity and the heat source side of the compressor 1 whose capacity is variable 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 blowing amount of the blower 20 is adjusted. Therefore, a target heating capacity can be obtained in each of the indoor units B, C, and D.

(Cooling main operation)
FIG. 5 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in the cooling main operation. Next, the cooling main operation will be described. In the air-conditioning apparatus 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 via the flow path switching valve 2 and is blown by the heat-source-side blower 20 having a variable air volume. It exchanges heat with air to become a two-phase high-temperature high-pressure state.

  Here, the control unit 70 adjusts the capacity of the variable capacity compressor 1 and the amount of air blown by the heat source side blower 20 so that the evaporation temperature and the condensation temperature of the indoor units B, C, and D become the predetermined target temperatures. I do. In addition, the control unit 70 includes a first electromagnetic opening / closing valve 44, a second electromagnetic opening / closing valve 45, and a third electromagnetic opening / closing valve 45 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 on-off 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, and controls 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. To adjust. As a result, an arbitrary amount of heat exchange can be obtained in the heat source side heat exchange unit 3, and a target heating capacity or cooling capacity can be obtained in each of the indoor units B, C, and D.

  The two-phase high-temperature high-pressure refrigerant is sent to the gas-liquid separation device 12 of the relay E via the third check valve 32 and the second connection pipe 7, and is separated into a gas refrigerant and a liquid refrigerant. . Then, the gas refrigerant separated by the gas-liquid separation device 12 flows into the indoor unit D to be heated through the heating electromagnetic valve 30 of the first branch portion 10 and the gas branch pipe 6d in this order, and the indoor heat The heat is exchanged with the indoor air in the exchanger 5 to condense and liquefy. At this time, the room is heated by the indoor unit D. Further, the refrigerant flowing out of the indoor heat exchanger 5 passes through the first flow control device 9 controlled by the subcool amount on the outlet side of the indoor heat exchanger 5 of the indoor unit D, and is slightly decompressed to the second flow rate. Flows into the branching portion 11. This refrigerant flows through the second bypass pipe 51 including the second check valve 52d to the second connection pipe 7 on the downstream side of the second flow control device 13.

  On the other hand, the liquid refrigerant separated by the gas-liquid separation device 12 passes through the second flow 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. And joins the refrigerant that has passed through the indoor unit D to be heated. After that, it flows into the second heat exchange unit 16 and is cooled by the second heat exchange unit 16.

  Part of the refrigerant cooled in the second heat exchange unit 16 passes through the first check valves 50b, 50c, passes through the liquid branch pipes 7b, 7c, and is cooled by the indoor unit B, Enter C. After the refrigerant flowing into the indoor units B and C enters the first flow control device 9 controlled by the superheat amount on the outlet side of the indoor side heat exchangers 5 of the indoor units B and C, the refrigerant is decompressed. It enters the indoor heat exchanger 5 where it undergoes heat exchange to evaporate and gasify. At this time, each room is cooled by the indoor units B and C. Then, it 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 in the second heat exchange unit 16 is set so 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. Through a controlled third flow control device 15. Then, after the heat is exchanged in the second heat exchange section 16 and the first heat exchange section 19 and evaporated, the refrigerant flows into the first connection pipe 6 and merges with the refrigerant that has passed through the indoor units B and C. The refrigerant that has joined in the first connection pipe 6 is sucked into the compressor 1 via the fourth check valve 33, the flow path switching valve 2, and the accumulator 4 of the heat source device A.

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

  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. Furthermore, since the liquid branch pipes 7b and 7c have a lower pressure than the second connection pipe 7, the refrigerant does not pass through the second check valves 52b and 52c. Furthermore, since the liquid branch pipe 7d has a higher pressure than the second connection pipe 7, the refrigerant does not pass through the first check valve 50d. 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 sub-cooling is not sufficiently performed. It is prevented from flowing into certain indoor units B and C.

(Heating main operation)
FIG. 6 is a circuit diagram showing a state of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention in the heating main operation. Next, the heating main operation will be described. In the air-conditioning apparatus 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 repeater 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 flows into the indoor units B and C to be heated in the order of the heating electromagnetic valve 30 and the gas branch pipes 6b and 6c in the first branch section 10, and flows into the indoor units B and C. The heat is exchanged with the indoor air in the exchanger 5 to be condensed and liquefied. At this time, each room is heated by the indoor units B and C. The condensed and liquefied refrigerant passes through the first flow control device 9 controlled by the subcooling amount on the outlet side of each indoor heat exchanger 5 of the indoor units C and D, and is slightly decompressed to the second branch 11. Inflow.

  The refrigerant flowing into the second branch portion 11 passes through the second bypass pipe 51 including the second check valves 52b and 52c and joins the second connection pipe 7, and the refrigerant flows into the second heat exchange section 16 in the second heat exchange section 16. Cooled. A part of the refrigerant cooled by the second heat exchange section 16 enters the indoor unit D 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 control device 9 controlled by the superheat amount at the outlet side of the indoor heat exchanger 5 and is decompressed, and then enters the indoor heat exchanger 5. And heat exchange to evaporate and gasify. At this time, the room is cooled by the indoor unit D. Then, it 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 in the second heat exchange unit 16 is set so 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. Through a controlled third flow control device 15. The refrigerant having passed through the third flow control device 15 exchanges heat with the refrigerant coming out of the indoor units B and C in the second heat exchange unit 16 and evaporates. 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 unit A via 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 having a variable blowing amount, and evaporates and gasifies.

  Here, the control unit 70 controls the capacity of the compressor 1 whose capacity is variable so that the evaporation temperature of the indoor unit D requiring cooling and the condensing temperature of the indoor units B and C requiring heating become the predetermined target temperatures. And the amount of air blown by the heat source side blower 20 is adjusted. In addition, the control unit 70 includes a first electromagnetic opening / closing valve 44, a second electromagnetic opening / closing valve 45, and a third electromagnetic opening / closing valve 45 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 on-off valve 47. Further, the control unit 70 opens and closes the fifth solenoid on-off valve 48 of the heat source side bypass passage 43 to control 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. As a result, an arbitrary amount of heat exchange can be obtained in the heat source side heat exchange unit 3, and a target heating capacity or cooling capacity in each of the indoor units B, C, and D can be obtained. Then, the refrigerant is sucked into the compressor 1 via the flow path switching valve 2 and the accumulator 4 of the heat source device A.

  In the heating main operation, the heating electromagnetic valve 30 connected to the indoor units B and C is open. The heating electromagnetic 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 solenoid valve 31a and the second cooling solenoid valve 31b connected to the indoor unit D are open.

  Further, 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 fifth check valve 34 and the sixth check valve 35. The second flow control device 13 is closed. Further, since the liquid branch pipes 7b and 7c have a higher pressure than the second connection pipe 7, the refrigerant does not pass through the first check valves 50b and 50c. Further, since the liquid branch pipe 7d has a lower pressure than the second connection pipe 7, the refrigerant does not pass through the second check valve 52d. The first check valve 50 and the second check valve 52 allow the refrigerant that has passed through the indoor units B and C, which require heating, to pass through the second heat exchange unit 16 so that the sub-cooler is not sufficiently cooled to perform cooling. It is prevented from flowing into the requested indoor unit D.

  FIG. 7 is a flowchart illustrating an 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 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 flowing at the time of heating are cooled by the first cooling electromagnetic valve 31a and the second cooling. After passing through the electromagnetic valve 31b for use, it flows into the first connection pipe 6 which is in a low pressure state during cooling. For this reason, a large pressure difference occurs before and after the cooling electromagnetic valve 31, and there is a possibility that refrigerant flowing 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 repeater E having the cooling electromagnetic valve 31. In the first embodiment, it is assumed that the addresses are younger in the order of the indoor units B, C, and D.

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

FIG. 8 is a flowchart showing an 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 31b opened by the valve control unit 71, the flow sound is generated by the determination unit 72 based on the state of the refrigerant detected by the state detection unit 80. It is determined whether or not it occurs (step ST3). Specifically, as shown in FIG. 8, the determination means 72, the pressure P of the refrigerant detected by merging the pressure detection sensor 56, whether or not the pressure threshold P ₀ or more is determined (step ST31) . As shown in FIG. 7, if 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 the flow noise of the refrigerant does not occur, and the operation returns to the normal operation. 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 possibility of occurrence, and the process proceeds to step ST4. The judging means 72 uses the pressure of the refrigerant detected by the downstream liquid outflow pressure detection sensor 26 and the merged pressure detection sensor 56 to determine the flow of the refrigerant when the pressure difference before and after the cooling electromagnetic valve 31 is equal to or greater than a threshold value. It may be determined that a sound is generated.

  In step ST4, the timing control means 73 checks whether or not 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. If the opening time threshold has elapsed (Yes in step ST4), the timing control unit 73 selects the second cooling electromagnetic valve 31b connected to the indoor unit B having the lower address (step ST5). Thereafter, the selected second cooling electromagnetic valve 31b is opened (step ST6). Thus, 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 the cooling electromagnetic valve 31 that is closed exists in the indoor unit that has requested the cooling (step ST7). If the cooling electromagnetic valve 31 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 the cooling. For this reason, in step ST7, there is a closed cooling electromagnetic valve 31, 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 or not the opening time threshold has elapsed since the second cooling solenoid valve 31b connected to the indoor unit B, which is another branch, is opened (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 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 second cooling electromagnetic valve 31b connected to the indoor unit D closed immediately before has been opened (step ST5). The second cooling electromagnetic valve 31b connected to the selected indoor unit D is opened (step ST6). Then, in step ST7, the control ends because there is no cooling electromagnetic valve 31 that is closed.

  According to the first embodiment, when the indoor units B, C, and D switch from the heating operation to the cooling operation, the timing control unit 73 opens the valve so as to open one of the plurality of electromagnetic valves 31 for cooling. The control unit 71 is controlled, and when it is determined that the flow noise of the refrigerant is generated, the valve control unit 71 is controlled so as to open one of the closed cooling electromagnetic valves 31. As described above, since the plurality of cooling electromagnetic valves 31 are opened in a stepwise manner, the flow noise of the refrigerant can be reduced without using an orifice. Therefore, the function of shutting off refrigerant leakage can be improved, and the flow noise of the refrigerant can be reduced.

  FIG. 9 is a circuit diagram showing a conventional air conditioner 200. As shown in FIG. 9, in the conventional air-conditioning apparatus 200, the first branch 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-conditioning apparatus 200, when switching from the heating operation to the cooling operation, the refrigerant flows in a stepwise manner in the order of the orifice d, the first cooling electromagnetic valve a, and the second cooling electromagnetic valve c. This is intended to reduce the flow noise of the refrigerant. However, the orifice d 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. Therefore, in the orifice d, the refrigerant to be supplied to the indoor unit during the heating operation is bypassed, so that the orifice d has a poor shutoff function.

  On the other hand, in the first embodiment, when the valve control unit 71 opens one of the plurality of cooling electromagnetic valves 31 and the timing control unit 73 determines that the flow noise of the refrigerant is generated, The valve control means 71 is controlled so as to open one of the closed cooling electromagnetic valves 31. Therefore, the flow noise of the refrigerant can be reduced without using an orifice. Therefore, the function of shutting off refrigerant leakage can be improved, and the flow noise of the refrigerant can be reduced.

  Further, the valve control means 71 has a function of keeping the opening of the first flow control device 9 constant when the indoor units B, C, D are switched from the heating operation to the cooling operation. Thereby, the first connection pipe 6 and the second connection pipe 7 are equalized in pressure. 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 value has elapsed since one of the closed cooling electromagnetic valves 31 was opened. It controls the control means 71. Accordingly, the refrigerant is prevented from flowing vigorously. Therefore, the flow noise of the refrigerant can be further reduced.

  Furthermore, the state detection unit 80 includes a merging pressure detection sensor 56 that detects the pressure of the refrigerant flowing through a portion where the liquid branch pipes 7b, 7c, 7d and the first connection pipe 6 are connected, and a plurality of liquid branches. A downstream liquid outflow pressure detection sensor 26 for detecting the pressure of the refrigerant flowing in the portion where the pipes 7b, 7c, 7d merge, and the judging means 72 comprises a merging pressure detection sensor 56 and a downstream liquid outflow pressure detection When the pressure difference of the refrigerant detected by the sensor 26 is equal to or larger than the threshold value, it is determined that the flow noise of the refrigerant is generated. Thereby, the pressure of the first connection pipe 6 can be optimized. Therefore, the flow noise of the refrigerant can be further reduced.

(First Modification)
FIG. 10 is a flowchart showing an operation of the air conditioner 100 according to the first modification of the first embodiment of the present invention. Next, a first modified example of the first embodiment will be described. In the first modification, the operation in step ST3 of FIG. 7 is different from that of the first embodiment, and the determining means 72 determines the difference between one pressure of the cooling electromagnetic valve 31 and the other pressure of the cooling electromagnetic valve 31. It is determined whether or not the flow noise of the refrigerant is generated based on the above.

As shown in FIG. 10, the determination means 72 determines whether one of the pressures of the first cooling solenoid valve 31a and the second cooling solenoid valve 31b, the first cooling solenoid valve 31a, and the second cooling solenoid valve. difference ΔPa of the other pressure 31b is, whether or not the pressure difference threshold [Delta] P ₀ or more is determined (step ST41). Specifically, the determination means 72 determines that the difference ΔPa between the pressure of the refrigerant detected by the merged pressure detection sensor 56 and the pressure of the refrigerant corresponding to the temperature of the refrigerant detected by the gas pipe temperature detection sensor 53 is When the difference is equal to or greater than the difference threshold ΔP _0, it is determined that the flow noise of the refrigerant is generated. That is, one of the pressures of the first cooling electromagnetic valve 31a and the second cooling electromagnetic valve 31b is detected by the combined pressure detection sensor 56. Further, the other pressures of the first cooling solenoid valve 31a and the second cooling solenoid valve 31b are calculated based on the saturation temperature detected by the gas pipe temperature detection sensor 53. As shown in FIG. 7, if the pressure difference [Delta] P is less than the pressure differential threshold [Delta] P ₀ (No in step ST3), the flow returns to normal operation. On the other hand, if the pressure difference [Delta] P over the pressure difference threshold value [Delta] P ₀ (Yes in step ST3), flow of operation proceeds to step ST4.

  As described above, in the first modified example, the state detection unit 80 is a combined pressure detection sensor that detects the pressure of the refrigerant flowing in the portion where the liquid branch pipes 7b, 7c, 7d and the first connection pipe 6 are connected. 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. If the difference between the temperature of the refrigerant detected by the gas pipe temperature detection sensor 53 and the pressure of the refrigerant corresponding to the temperature of the refrigerant is equal to or greater than the pressure difference threshold value, it is determined that the flow noise of the refrigerant is generated. This first modification also has the same effect as the first embodiment.

(Second modification)
FIG. 11 is a flowchart showing an operation of the air conditioner 100 according to the second modification of Embodiment 1 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 of FIG. 7 is different from that of the first embodiment, and the determining unit 72 determines the subcool value on the outlet side of the indoor heat exchanger 5 of the indoor unit performing the heating operation. Based on this, it is determined whether or not the flow noise of the refrigerant is generated.

As shown in FIG. 11, the determination means 72, the outlet side of the subcooling value SCa of the indoor side heat exchanger 5 where the indoor unit having 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 temperature of the refrigerant 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. 7, 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.

  As described above, in the second modification, the repeater E has an inflow side connected to the second connection pipe 7, a gas outflow side connected to the heating solenoid valve 30, and a liquid outflow side connected to the liquid branch pipes 7b, 7c, 7d. And a gas-liquid separation device 12 for separating the gas refrigerant and the liquid refrigerant, and the state detection unit 80 detects the pressure of the refrigerant on the liquid outflow side of the gas-liquid separation device 12 by a liquid outflow pressure detection 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, 7d, and the judging means 72 determines the pressure of the refrigerant detected by the liquid outflow pressure detection sensor 25. If the subcool value on the outlet side of the indoor heat exchanger 5 calculated based on the temperature of the refrigerant corresponding to the temperature of the refrigerant and the temperature of the refrigerant detected by the liquid pipe temperature detection sensor 54 is equal to or greater than the subcool threshold, Judge that the flowing sound of It is intended. Also in the second modified example, the same effect as in the first embodiment can be obtained.

(Third Modification)
FIG. 12 is a flowchart showing an operation of the air-conditioning apparatus 100 according to the third modified example of Embodiment 1 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 of FIG. 7 is different from that of the first embodiment, and the determination unit 72 determines that the stop threshold value is set after the indoor heat exchanger 5 of the indoor unit performing the heating operation is stopped. It is determined whether or not the flow noise of the refrigerant is generated depending on whether or not the time has elapsed.

As shown in FIG. 12, the determination means 72, the elapsed time Ta from the stopped indoor heat exchanger 5 which indoor unit has that heating operation, whether or not the threshold time elapsed T ₀ or less It is determined (step ST61). As shown in FIG. 7, when the elapsed time Ta is equal to or longer than the threshold elapsed time T ₀ (No in step ST3), the difference between the pressure of the first connection pipe 6 and the pressure of the second connection pipe 7 is reduced. Then, it is determined that the flow noise of the refrigerant does not occur, and the operation returns to the normal operation. 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.

  As described above, in the third modified example, the determination unit 72 determines whether the indoor unit B, C, or D that is performing the heating operation has stopped after the indoor heat exchanger 5 has stopped until the stop threshold time has elapsed. It is determined that the flow noise of the refrigerant is generated. Also in the third modified example, the same effect as that of 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 first connection pipe, 6b, 6c, 6d gas branch pipe, 7 second connection pipe, 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 separation device, 13 second flow control device, 14 first bypass pipe, 15 third flow control device, 16 second heat exchange section, 18 discharge pressure detection sensor, 19 first heat exchange section, 20 heat source side blower, 25 liquid outflow pressure detection sensor, 26 Downstream side 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 5th check valve, 35 6th check 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 path, 44 first electromagnetic on / off valve, 45 second electromagnetic on / off valve Valve, 46 third solenoid on-off valve, 47 fourth solenoid on-off valve, 48 fifth solenoid on-off valve, 50b first check valve, 50c first check valve, 50d first check valve, 51 second bypass pipe, 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 junction pressure detection sensor , 70 control unit, 71 valve control unit, 72 determination unit, 73 timing control unit, 80 state detection unit, 100 air conditioner, 110 first branch unit, 111 second branch unit, 112 gas-liquid separation device, 113 Second flow control device, 11 The third flow rate controller, 116 second heat exchange unit, 119 first heat exchanging portion, 200 air conditioner, A heat source unit, B indoor unit, C indoor unit, D indoor unit, E repeater.

Claims (6)

A heat source machine having a compressor and a heat source side heat exchanger;
Each having a first flow control device and an indoor heat exchanger, a plurality of indoor units for cooling operation or heating operation,
A refrigerant connected to the heat source unit by a first connection pipe and a second connection pipe, respectively connected to the indoor units by a plurality of gas branch pipes and a plurality of liquid branch pipes, and supplied from the heat source unit. A repeater for distributing to the plurality of indoor units,
A state detection unit that detects a state of the refrigerant flowing through the gas branch pipe,
A control unit for controlling the operation of the repeater,
The repeater,
A plurality of cooling solenoid valves connected in parallel, 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 second connection pipe, is opened during the heating operation, and has a heating solenoid valve closed during the cooling operation,
The control unit includes:
Valve control means for controlling the opening and closing of the plurality of cooling electromagnetic valves,
When refrigerant flows through the cooling solenoid valve, based on the state of the refrigerant detected by the state detection unit, a determination unit that determines whether or not a flowing sound is generated,
When switching the indoor unit from the heating operation to the cooling operation, the Cv value of the plurality of cooling solenoid valves connected to all the indoor units switched to the cooling operation is opened to open one having the smallest Cv value. Timing of controlling the valve control means, and controlling the valve control means to open one of the closed cooling electromagnetic valves when it is determined by the determination means that a refrigerant flow noise is generated. Control means,
The valve control means,
An air conditioner having a function of keeping the opening of the first flow control device constant when the indoor unit is switched from a heating operation to a cooling operation. The timing control means includes:
When it is determined that the flow noise of the refrigerant is generated by the determination means, when an open time threshold has elapsed since one of the closed cooling electromagnetic valves is opened, the cooling electromagnetic valve that is closed The air conditioner according to claim 1, wherein the valve control means is controlled so as to open one. The state detector,
A merging pressure detection sensor that detects a pressure of a refrigerant flowing through a portion where the liquid branch pipe and the first connection pipe are connected;
A downstream liquid outflow pressure detection sensor that detects the pressure of the refrigerant flowing in the portion where the plurality of liquid branch pipes join,
The determining means includes:
The air conditioner according to claim 1 or 2, wherein when the pressure difference of the refrigerant detected by the merging pressure detection sensor and the downstream liquid outflow pressure detection sensor is equal to or larger than a threshold value, it is determined that a refrigerant flow noise is generated. . The repeater,
A gas-liquid separation device that has an inflow side connected to the second connection pipe, a gas outflow side connected to the heating solenoid valve, a liquid outflow side connected to the liquid branch pipe, and separates a gas refrigerant and a liquid refrigerant. Have
The state detector,
A liquid outflow pressure detection sensor that detects the pressure of the refrigerant on the liquid outflow side of the gas-liquid separation device,
A liquid pipe temperature detection sensor that detects the temperature of the refrigerant flowing through the liquid branch pipe,
The determining means includes:
The outlet side of the indoor heat exchanger calculated based on the temperature of the refrigerant corresponding to the pressure of the refrigerant detected by the liquid outflow pressure detection sensor and the temperature of the refrigerant detected by the liquid pipe temperature detection sensor The air conditioner according to any one of claims 1 to 3, wherein when the subcool value is equal to or greater than the subcool threshold value, it is determined that a refrigerant flow noise is generated. The state detector,
A merging pressure detection sensor that detects a pressure of a refrigerant flowing through a portion where the liquid branch pipe and the first connection pipe are connected;
Having a gas pipe temperature detection sensor that detects the temperature of the refrigerant flowing through the gas branch pipe,
The determining means includes:
When the difference between the pressure of the refrigerant detected by the merged pressure detection sensor and the pressure of the refrigerant corresponding to the temperature of the refrigerant detected by the gas pipe temperature detection sensor is equal to or greater than a pressure difference threshold, the flow noise of the refrigerant The air conditioner according to any one of claims 1 to 4. The determining means includes:
It is determined that the flow noise of the refrigerant is generated until the stop threshold time elapses after the indoor heat exchanger included in the indoor unit that is performing the heating operation is stopped. The air conditioner according to claim 1.

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