WO2018011994A1

WO2018011994A1 - Air conditioning device

Info

Publication number: WO2018011994A1
Application number: PCT/JP2016/071081
Authority: WO
Inventors: 祐治本村
Original assignee: 三菱電機株式会社
Priority date: 2016-07-15
Filing date: 2016-07-15
Publication date: 2018-01-18
Also published as: GB2566201B; GB201820586D0; JP6701337B2; GB2566201A; JPWO2018011994A1

Abstract

Provided is an air conditioning device having a refrigerant circuit which is formed by connecting an outdoor unit and a plurality of indoor units by refrigerant piping and through which a refrigerant is circulated. The air conditioning device comprises: a refrigerant leakage detection device which is provided in a space to be air conditioned and which detects the leakage of the refrigerant to the space to be air conditioned; a plurality of refrigerant pressure detection devices provided to the refrigerant piping and detecting the pressure of the refrigerant flowing through the refrigerant piping; a refrigerant shutoff valve provided in the refrigerant piping and permitting or preventing the flow of the refrigerant; and a control device for controlling the opening and closing of the refrigerant shutoff valve. The control device determines, on the basis of the result of detection by the refrigerant leakage detection device or the refrigerant pressure detection devices, whether the refrigerant has leaked. Upon determining that the refrigerant has leaked, the control device performs control to close the refrigerant shutoff valve and specifies the location of the leakage of the refrigerant on the basis of a variation in the pressure of the refrigerant within the refrigerant piping, the variation being detected by the refrigerant pressure detection devices.

Description

Air conditioner

The present invention relates to an air conditioner applied to a building multi air conditioner or the like.

2. Description of the Related Art Conventionally, there are air conditioners in which an outdoor unit that is a heat source unit is disposed outside a building such as a rooftop of a building, and an indoor unit is disposed in a building, such as a multi air conditioner for buildings. In such an air conditioner, the refrigerant circulating in the refrigerant circuit dissipates or absorbs heat by exchanging heat with the air supplied to the use side heat exchanger provided in the indoor unit, and heats or cools the air. To do. Then, the heated or cooled air is sent into the air-conditioning target space, thereby heating or cooling the space.

Further, as an air conditioner, for example, there is a multi-air conditioner for simultaneous cooling and heating that can simultaneously use both cooling operation and heating operation in the same system (see, for example, Patent Document 1). In such an air conditioner, a branch unit is provided between the outdoor unit and the indoor unit, and the refrigerant heated or cooled by the outdoor unit is separated into liquid refrigerant and gas refrigerant in the branch unit. In this air conditioner, the liquid refrigerant is allowed to flow into the use side heat exchanger of the indoor unit, and the liquid refrigerant evaporates, whereby the cooling operation can be performed, and the gas refrigerant is allowed to flow into the use side heat exchanger. The heating operation can be performed by condensing the gas refrigerant.

As a refrigerant used for an air conditioner, generally, a substance containing hydrogen and carbon such as R410A which is nonflammable, R32 which is weakly flammable, and propane which shows strong flammability is used. These refrigerants, when released into the atmosphere, have different lifetimes until they are decomposed and changed to other substances, but they are highly stable in refrigerant circuits and used as refrigerants for a long period of several decades. can do. In addition, a refrigerant that uses a natural refrigerant such as carbon dioxide (CO ₂ ) has been proposed.

JP 2011-112233 A

By the way, in the above-described conventional air conditioner, a plurality of indoor units are connected to one refrigerant pipe, and the refrigerant is conveyed to the plurality of indoor units in order to perform a cooling operation or a heating operation. When the number of connected indoor units increases, the total refrigerant amount of the refrigerant circulating in the refrigerant circuit increases accordingly. Therefore, when refrigerant leakage occurs, the amount of refrigerant that leaks increases in proportion to the total amount of refrigerant. For example, when refrigerant leaks indoors, the refrigerant concentration in the space may increase as the indoor space becomes narrower.

In addition, when the distance from the installation location of the outdoor unit to the installation location of the indoor unit is long, the refrigerant pipe connecting the outdoor unit and the indoor unit becomes long. And if refrigerant piping becomes long, the total refrigerant | coolant amount of the refrigerant | coolant which circulates through a refrigerant circuit will increase according to it. Even in this case, when refrigerant leakage occurs, the amount of refrigerant leaking increases in proportion to the total refrigerant amount. Therefore, for example, when refrigerant leakage occurs in the room, the refrigerant concentration in the space may increase as the indoor space becomes narrower.

On the other hand, when a refrigerant leak occurs in a large-scale air conditioner, it takes time to identify the location of the refrigerant leakage in the refrigerant circuit, and it can be used to restore the leakage location and to refill the leaked refrigerant. It takes time. Therefore, there is a possibility that convenience may deteriorate.

The present invention has been made in view of the above-described problems in the prior art, and is an air conditioner that can easily identify a leakage location while suppressing the leakage of the refrigerant when the refrigerant leaks. The purpose is to provide.

An air conditioner of the present invention is an air conditioner in which a refrigerant circuit is formed by connecting an outdoor unit and a plurality of indoor units with refrigerant pipes and circulating a refrigerant, and is provided in an air-conditioning target space. A refrigerant leakage detection device that detects leakage of the refrigerant to the air-conditioning target space; a plurality of refrigerant pressure detection devices that are provided in the refrigerant piping and that detect the pressure of the refrigerant flowing through the refrigerant piping; and the refrigerant piping. A refrigerant shut-off valve provided to permit or block the flow of the refrigerant, and a control device that controls opening and closing of the refrigerant shut-off valve, wherein the control device detects the refrigerant leak detection device or the refrigerant pressure detection device Based on the result, it is determined whether or not the refrigerant has leaked. When it is determined that the refrigerant has leaked, the refrigerant shut-off valve is controlled to be closed, and the refrigerant pressure detection device detects the refrigerant. Based on the variation of the pressure of the refrigerant in the medium pipe, it is to identify the leakage location of the refrigerant.

As described above, according to the air conditioning apparatus of the present invention, when it is determined that the refrigerant has leaked based on the detection result of the refrigerant leak detection device or the refrigerant pressure detection device, the refrigerant shut-off valve is closed to The leakage of the refrigerant when the leakage occurs can be suppressed, and the leakage location can be easily identified by the pressure fluctuation of the refrigerant in the refrigerant piping based on the detection result of the refrigerant pressure detection device.

It is the schematic which shows the example of installation of the air conditioning apparatus which concerns on Embodiment 1. FIG. It is the schematic which shows an example of the circuit structure of the air conditioning apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows an example of a structure of the control apparatus of FIG. 3 is a flowchart illustrating an example of a flow of refrigerant leakage detection processing in the air-conditioning apparatus according to Embodiment 1. It is the schematic which shows the example of installation of the air conditioning apparatus which concerns on Embodiment 2. FIG. 6 is a schematic diagram illustrating an example of a circuit configuration of an air-conditioning apparatus according to Embodiment 2. FIG. It is a block diagram which shows an example of a structure of the control apparatus of FIG. 6 is a flowchart illustrating an example of a flow of refrigerant leakage detection processing in the air-conditioning apparatus according to Embodiment 2. It is the schematic which shows the example of installation of the air conditioning apparatus which concerns on this Embodiment 3. FIG.

Embodiment 1 FIG.
Hereinafter, the air-conditioning apparatus according to Embodiment 1 of the present invention will be described. The air conditioner according to Embodiment 1 is a cooling / heating switching type air conditioner in which a plurality of indoor units can simultaneously perform either one of a cooling operation and a heating operation.

[Installation example of air conditioner]
FIG. 1 is a schematic diagram illustrating an installation example of the air-conditioning apparatus 1 according to the first embodiment. As shown in FIG. 1, the air conditioner 1 includes an outdoor unit 10 as a heat source unit and a plurality of indoor units 20. The outdoor unit 10 and the plurality of indoor units 20 are connected by two refrigerant pipes 30. Thereby, a refrigerant circuit in which the refrigerant circulates in the refrigerant pipe 30 is formed.

In this example, two

indoor units

20A and 20B are connected to one outdoor unit 10. In the following description, when it is not necessary to distinguish between the

indoor units

20A and 20B, they are simply referred to as “indoor unit 20” as appropriate.

The outdoor unit 10 is usually installed in a space outside the building 2 such as a building, for example, an outdoor space 3 such as a rooftop. The outdoor unit 10 generates cold or warm heat, and supplies the generated cold or warm heat to the indoor unit 20 via the refrigerant pipe 30.

The indoor unit 20 supplies cooling air or heating air to a space inside the building 2, for example, an indoor space 4 that is an air-conditioning target space such as a living room or a server room, by the cooling or heating supplied from the outdoor unit 10. To do. In this example, the indoor unit 20 is installed in a space 5 such as the back of the ceiling, which is inside the building 2 but is different from the indoor space 4. Moreover, the indoor unit 20 can also be used, for example, as floor heating that is installed under the floor and warms the floor surface by heat supplied during heating operation.

The number of indoor units 20 connected to the outdoor unit 10 is not limited to this example. For example, one indoor unit 20 may be connected to one outdoor unit 10, or two or four indoor units 20 may be connected. Two or more indoor units 20 may be connected. Further, for example, a plurality of outdoor units 10 may be provided, and one or a plurality of indoor units 20 may be connected to the plurality of outdoor units 10. That is, the number of outdoor units 10 and indoor units 20 can be appropriately determined according to the scale of the building 2 where the air conditioner 1 is installed.

Here, in the air conditioner 1 of the first embodiment, as the refrigerant circulating in the refrigerant circuit, for example, a single refrigerant such as R-22, R-134a, R-32, R-410A, R-404A, etc. azeotropic refrigerant mixture, and the refrigerant non-azeotropic refrigerant such as R-407C, global warming potential such as _CF 3 CF = CH ₂ including a double bond in the chemical formula is a relatively small value that Mixtures or natural refrigerants such as CO ₂ and propane can be used.

The refrigerant pipe 30 is provided with a refrigerant pressure detection device 6 for detecting the pressure of the refrigerant flowing inside. The refrigerant pipe 30 is provided with a refrigerant shut-off valve 7 for blocking the refrigerant flowing into and out of each indoor unit 20 corresponding to each indoor unit 20. Details of the refrigerant pressure detection device 6 and the refrigerant cutoff valve 7 will be described later.

In the indoor space 4, a refrigerant leak detection device 8 is installed. The refrigerant leak detection device 8 is for detecting the refrigerant leak when the refrigerant leaks from the refrigerant pipe 30 and flows into the indoor space 4. The refrigerant leakage detection device 8 supplies a detection signal indicating a detection result of refrigerant leakage into the indoor space 4 to the control device 40 described later.

In this example, the refrigerant leak detection device 8 is installed, for example, at the lower end of the indoor space 4. Note that the installation position of the refrigerant leakage detection device 8 is not limited to this example, and may be installed at any position as long as the refrigerant leakage can be accurately detected.

As the refrigerant leak detection device 8, for example, a semiconductor or infrared leak detection device can be used. The refrigerant leakage detection device 8 is not limited to this, and any apparatus can be used as long as the refrigerant can be detected, for example.

[Circuit configuration of air conditioner]
FIG. 2 is a schematic diagram illustrating an example of a circuit configuration of the air-conditioning apparatus 1 according to the first embodiment. In the example of FIG. 2, a case where two indoor units 20 A and 20 B are connected to one outdoor unit 10 via the refrigerant pipe 30 is shown. As described above, the number of outdoor units 10 and indoor units 20 is not limited to this example.

(Outdoor unit)
The outdoor unit 10 includes a compressor 11, a refrigerant flow switching device 12, a heat source side heat exchanger 13, and an accumulator 14.

The compressor 11 sucks a low-temperature and low-pressure refrigerant, compresses the refrigerant, and discharges it in a high-temperature and high-pressure state. As the compressor 11, for example, an inverter compressor or the like that can control the capacity that is the refrigerant delivery amount per unit time by arbitrarily changing the drive frequency can be used.

The refrigerant flow switching device 12 is, for example, a four-way valve, and switches between a cooling operation and a heating operation by switching the direction in which the refrigerant flows. The refrigerant flow switching device 12 is not limited to the above-described four-way valve, and for example, other valves may be used in combination.

The heat source side heat exchanger 13 performs heat exchange between air (hereinafter referred to as “outdoor air” as appropriate) supplied by a blower such as a fan (not shown) and the refrigerant. Specifically, the heat source side heat exchanger 13 functions as a condenser that radiates the heat of the refrigerant to the outdoor air and condenses the refrigerant during the cooling operation. The heat source side heat exchanger 13 functions as an evaporator that evaporates the refrigerant during the heating operation and cools the outdoor air by the heat of vaporization at that time.

The accumulator 14 is provided on the low pressure side that is the suction side of the compressor 11. The accumulator 14 stores surplus refrigerant generated due to a difference in operating state between the cooling operation and the heating operation, surplus refrigerant with respect to a transient change in operation, and the like.

(Indoor unit)
The

indoor units

20A and 20B perform, for example, cooling and heating of air in an air-conditioning target space. The indoor unit 20A includes an expansion device 21A that is an indoor heat exchanger and a use side heat exchanger 22A. The indoor unit 20B includes a throttle device 21B and a use side heat exchanger 22B.

In the following description, when it is not necessary to distinguish between the

diaphragm devices

21A and 21B, they will be simply referred to as “the diaphragm device 21” as appropriate. Similarly, the use

side heat exchangers

22A and 22B are simply referred to as “use side heat exchanger 22” as appropriate.

The expansion device 21 decompresses and expands the refrigerant by adjusting the flow rate of the refrigerant. The expansion device 21 is constituted by a valve capable of controlling the opening, such as an electronic expansion valve. The diaphragm device 21 is not limited to this, and other diaphragm devices such as capillaries can also be used.

The use side heat exchanger 22 performs heat exchange between air and a refrigerant supplied by a blower such as a fan (not shown). Thereby, heating air or cooling air supplied to the indoor space 4 is generated. Specifically, the use-side heat exchanger 22 functions as an evaporator when the refrigerant carries cold heat during the cooling operation, and cools the air in the indoor space 4 that is the air-conditioning target space by cooling the air. Do. In addition, the use side heat exchanger 22 functions as a condenser when the refrigerant is transporting warm heat during the heating operation, and heats the air in the indoor space 4 to perform heating.

Refrigerant

pressure detection devices

6 a and 6 b are provided in the refrigerant pipe 30 that connects the outdoor unit 10 and the indoor unit 20. The refrigerant pressure detection device 6a is provided between the branch point 35a of the refrigerant pipe 30 and the indoor unit 20B. The refrigerant pressure detection device 6b is provided between the branch point 35b of the refrigerant pipe 30 and the indoor unit 20B.

These refrigerant

pressure detection devices

6a and 6b are used in an outdoor space when the air conditioner 1 is in an operating state and the refrigerant is circulating in the refrigerant pipe 30 or when the air conditioner 1 is in an operation stop state. 3 and the refrigerant saturation pressure corresponding to the temperature of the indoor space 4 are detected. Then, the refrigerant

pressure detection devices

6a and 6b output a detection signal indicating the refrigerant pressure as a detection result to the control device 40 described later.

The refrigerant piping 30 that connects the outdoor unit 10 and the indoor unit 20 is provided with refrigerant cutoff valves 7a to 7d. The refrigerant shut-off valve 7a is provided between the branch point 35a of the refrigerant pipe 30 and the indoor unit 20A. The refrigerant shut-off valve 7b is provided between the indoor unit 20A and the branch point 35b of the refrigerant pipe 30. The refrigerant cutoff valve 7c is provided between the branch point 35a and the indoor unit 20B. The refrigerant shut-off valve 7d is provided between the indoor unit 20B and the branch point 35b.

These refrigerant cutoff valves 7a to 7d are controlled by the control device 40 to open and close the valves, and allow or block the refrigerant flow in the refrigerant piping 30. The refrigerant shut-off valves 7a to 7d are in the “open” state in the normal state, and the refrigerant flow is allowed. When refrigerant leakage is detected, the refrigerant cutoff valves 7a to 7d are brought into a “closed” state based on the control of the control device 40, and the refrigerant flow is blocked.

When the

refrigerant shutoff valves

7a and 7b are in the “closed” state, the indoor unit 20A is disconnected from the outdoor unit 10 and can be made independent of the air conditioner 1. Further, when the

refrigerant shutoff valves

7c and 7d are in the “closed” state, the indoor unit 20B is disconnected from the outdoor unit and can be made independent of the air conditioner 1. Any one of the refrigerant shut-off valves 7a to 7d can be used as long as it has a function of shutting off the refrigerant circuit.

(Control device)
The air conditioner 1 is provided with a control device 40. The control device 40 includes, for example, software executed on an arithmetic device such as a microcomputer or a CPU (Central Processing Unit), hardware such as a circuit device that realizes various functions, and the like. To control.

For example, the control device 40 determines the compressor frequency of the compressor 11 and the valve opening degree of the expansion device 21 based on the operation contents instructed by the user, the detection results from the refrigerant pressure detection device 6 and the refrigerant leakage detection device 8, and the like. The opening and closing of the refrigerant shutoff valve 7 is controlled. In addition, the control device 40 performs a process of specifying a refrigerant leakage location based on detection results from the refrigerant pressure detection device 6 and the refrigerant leakage detection device 8 when the refrigerant leaks from the refrigerant pipe 30.

[Configuration of control device]
FIG. 3 is a block diagram showing an example of the configuration of the control device 40 of FIG. As shown in FIG. 3, the control device 40 includes a leak determination unit 41, a pressure comparison unit 42, a shut-off valve control unit 43, and a leak location determination unit 44. In addition, about the control apparatus 40 in this example, only the part relevant to this Embodiment 1 is shown in figure, and illustration is abbreviate | omitted about the other part.

The leakage determination unit 41 determines whether or not refrigerant leakage has occurred based on information indicated by the detection signal received from the refrigerant leakage detection device 8 or information indicating a comparison result from the pressure comparison unit 42 described later. The leakage determination unit 41 supplies information indicating the determination result to the cutoff valve control unit 43.

The pressure comparison unit 42 compares the pressure indicated by the detection signal received from the refrigerant pressure detection device 6 with a reference pressure (hereinafter referred to as “pressure determination value” as appropriate) P as a preset pressure determination value. To do. The pressure comparison unit 42 supplies information indicating the comparison result to the leakage determination unit 41 or a leakage point determination unit 44 described later.

Note that the pressure determination value P is determined from, for example, the pressure of the refrigerant existing in the refrigerant pipe 30 during operation stop. As the pressure determination value P, for example, a low value or an average value of the refrigerant saturation pressure calculated from the temperature of the outdoor space 3 (hereinafter referred to as “outdoor temperature” as appropriate) or the indoor temperature of the indoor space 4 is used. Can be used.

The shut-off valve control unit 43 receives information indicating the judgment result by the leak judgment unit 41 and controls the opening and closing of the refrigerant shut-off valve 7 based on this information. For example, when the information indicating the determination result indicates the leakage of the refrigerant, the cutoff valve control unit 43 controls the refrigerant cutoff valve 7 to close.

The leak location determination unit 44 determines the leak location based on the information received from the pressure comparison unit 42. Then, the leakage location determination unit 44 supplies information indicating the determination result to the cutoff valve control unit 43. For example, the leakage location determination unit 44 determines that the refrigerant has leaked from the surrounding refrigerant pipe 30 in which the refrigerant pressure detection device 6 showing a pressure lower than the pressure determination value P is installed.

[Operation of air conditioner]
Next, the operation | movement of the refrigerant | coolant in the cooling only operation mode in the air conditioning apparatus 1 which has the said structure and a heating only operation mode is demonstrated. As operation modes in the air-conditioning apparatus 1 according to Embodiment 1, there are a cooling only operation mode in which both the

indoor units

20A and 20B perform a cooling operation, and a heating only operation mode in which a heating operation is performed. In the example shown in FIG. 2, the state indicated by the solid line of the refrigerant flow switching device 12 indicates the state in the cooling only operation mode, and the state indicated by the dotted line indicates the state in the heating only operation mode.

(Cooling mode only)
First, the operation of the refrigerant in the cooling only operation mode in which the

indoor units

20A and 20B perform the cooling operation will be described. In the cooling only operation mode, the refrigerant flow switching device 12 in the outdoor unit 10 is switched to the state shown by the solid line in FIG. The low-temperature and low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature and high-pressure gas refrigerant.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the heat source side heat exchanger 13 via the refrigerant flow switching device 12. The high-temperature and high-pressure gas refrigerant that has flowed into the heat source side heat exchanger 13 condenses while exchanging heat with the outdoor air and dissipates heat, and becomes a supercooled high-pressure liquid refrigerant that flows out of the heat source side heat exchanger 13. Then, the high-pressure liquid refrigerant flows out from the outdoor unit 10.

The high-pressure liquid refrigerant that has flowed out of the outdoor unit 10 branches via the refrigerant pipe 30 and flows into the

indoor units

20A and 20B. The high-pressure liquid refrigerant that has flowed into the indoor unit 20A is depressurized by the expansion device 21A via the refrigerant shut-off valve 7a provided in the refrigerant pipe 30, and becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant, which is supplied to the use-side heat exchanger 22A. Inflow. The low-temperature and low-pressure gas-liquid two-phase refrigerant that has flowed into the use side heat exchanger 22A exchanges heat with the room air, absorbs heat and evaporates, thereby cooling the room air and becomes a low-temperature and low-pressure gas refrigerant to use side heat exchange. Out of the vessel 22A. The low-temperature and low-pressure gas refrigerant that has flowed out of the use-side heat exchanger 22A flows out of the indoor unit 20A.

The high-pressure liquid refrigerant that has flowed into the indoor unit 20B is decompressed by the expansion device 21B via the refrigerant shut-off valve 7c provided in the refrigerant pipe 30, and becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant. It flows into 22B. The low-temperature and low-pressure gas-liquid two-phase refrigerant that has flowed into the use side heat exchanger 22B exchanges heat with the indoor air, absorbs heat and evaporates, thereby cooling the indoor air and becomes a low-temperature and low-pressure gas refrigerant to use-side heat exchange. Out of the vessel 22B. The low-temperature and low-pressure gas refrigerant that has flowed out of the use-side heat exchanger 22B flows out of the indoor unit 20B.

The low-temperature and low-pressure gas refrigerant that has flowed out of the indoor unit 20A and the low-temperature and low-pressure gas refrigerant that has flowed out of the indoor unit 20B are joined together via the refrigerant shut-off valve 7c and the refrigerant shut-off valve 7d provided in the refrigerant pipe 30, respectively. It flows into the outdoor unit 10. The low-temperature and low-pressure gas refrigerant that has flowed into the outdoor unit 10 passes through the refrigerant flow switching device 12 and the accumulator 14 and is sucked into the compressor 11.

(All heating operation mode)
Next, the operation of the refrigerant in the heating only operation mode in which the

indoor units

20A and 20B perform the heating operation will be described. In the heating only operation mode, the refrigerant flow switching device 12 is switched to the state indicated by the dotted line in FIG. The low-temperature and low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature and high-pressure gas refrigerant.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows out of the outdoor unit 10 through the refrigerant flow switching device 12. The high-temperature and high-pressure gas refrigerant that has flowed out of the outdoor unit 10 branches via the refrigerant pipe 30 and flows into the

indoor units

20A and 20B.

The high-temperature and high-pressure gas refrigerant that has flowed into the indoor unit 20A flows into the use-side heat exchanger 22A, exchanges heat with the indoor air, condenses while dissipating heat, and becomes a high-pressure liquid refrigerant in a supercooled state. It flows out of the exchanger 22A. The high-pressure liquid refrigerant that has flowed out of the use-side heat exchanger 22A is decompressed by the expansion device 21A, becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant, and flows out of the indoor unit 20A.

The high-temperature and high-pressure gas refrigerant that has flowed into the indoor unit 20B flows into the use-side heat exchanger 22B, condenses while exchanging heat by exchanging heat with room air, and is used as a supercooled high-pressure liquid refrigerant. It flows out from the side heat exchanger 22B. The high-pressure liquid refrigerant that has flowed out of the use-side heat exchanger 22B is decompressed by the expansion device 21B, becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant, and flows out of the indoor unit 20B.

The low-temperature and low-pressure gas-liquid two-phase refrigerant that has flowed out of the indoor unit 20A and the low-temperature and low-pressure gas-liquid two-phase refrigerant that has flowed out of the indoor unit 20B are joined together via the refrigerant shut-off valve 7a and the refrigerant shut-off valve 7c. Flows into the machine 10.

The low-temperature and low-pressure gas-liquid two-phase refrigerant that has flowed into the outdoor unit 10 flows into the heat source side heat exchanger 13, exchanges heat with outdoor air, absorbs and evaporates, and becomes a low-temperature and low-pressure gas refrigerant, thereby heat-source-side heat exchange. It flows out of the vessel 13. The low-temperature and low-pressure gas refrigerant flowing out from the heat source side heat exchanger 13 passes through the refrigerant flow switching device 12 and the accumulator 14 and is sucked into the compressor 11. Thereafter, the above-described circulation is repeated.

In the first embodiment, the air conditioner 1 performs the cooling operation or the heating operation so that the temperature of the indoor space 4 (hereinafter, appropriately referred to as “indoor temperature”) becomes a set temperature. At this time, when the room temperature reaches the set temperature, the air conditioner 1 stops the supply of the refrigerant to the use side heat exchanger 22 of the indoor unit 20 and performs a blowing operation by the blower attached to the use side heat exchanger 22. Switch to mode.

In addition, even when the room temperature does not reach the set temperature, the air conditioner 1 stops the supply of the refrigerant to the use side heat exchanger 22 when, for example, there is an instruction from the user, The operation mode is switched to a stop mode in which the operation of the blower attached to the use side heat exchanger 22 is also stopped.

[Refrigerant leak detection processing]
Next, processing when refrigerant leakage occurs will be described. FIG. 4 is a flowchart illustrating an example of the flow of the refrigerant leakage detection process in the air-conditioning apparatus 1 according to Embodiment 1. Here, the case where the leakage of the refrigerant is detected in a state where the operation of the air conditioner 1 is stopped will be described.

First, when leakage of the refrigerant is detected from the refrigerant pipe 30 in step S1, the leakage determination unit 41 of the control device 40 determines whether the refrigerant leakage is detected by the refrigerant leakage detection device 8 in step S2. Judge whether or not.

When it is determined that the refrigerant leakage is detected by the refrigerant leakage detection device 8 (step S2; Yes), the leakage determination unit 41 determines that the refrigerant has leaked into the indoor space 4, and the process proceeds to step S3. To do. In step S 3, the cutoff valve control unit 43 of the control device 40 performs control so that the target refrigerant cutoff valve 7 is closed.

In this case, since it is necessary to suppress the leakage of the refrigerant to the indoor space 4, the shut-off valve control unit 43 includes the refrigerant shut-off valves of the refrigerant pipes 30 connected to all the indoor units 20 installed in the indoor space 4. 7 and the refrigerant shutoff valve 7 on the upstream side thereof are controlled to close. Therefore, in the example shown in FIGS. 1 and 2, the shutoff valve control unit 43 controls the coolant shutoff valves 7a to 7d as the “target coolant shutoff valve 7” to be closed. Thereby, the refrigerant circuit corresponding to the indoor unit 20 installed in the indoor space 4 can be separated from the air conditioner 1.

Next, in step S 4, the leakage point determination unit 44 of the control device 40 identifies the leakage point of the refrigerant in the refrigerant pipe 30. The location of the refrigerant leakage can be identified based on, for example, fluctuations in the pressure of the refrigerant in the refrigerant pipe 30 using the detection result of the refrigerant pressure detection device 6. Specifically, the pressure comparison unit 42 compares the pressure indicated by the detection signal received from each refrigerant pressure detection device 6 provided in the refrigerant pipe 30 with the pressure determination value P. And the leak location determination part 44 judges that the refrigerant | coolant leaked from the surrounding refrigerant | coolant piping 30 in which the refrigerant | coolant pressure detection apparatus 6 which shows a pressure lower than the pressure judgment value P was installed.

On the other hand, when it is determined in step S2 that the refrigerant leakage detection device 8 has not detected the leakage (step S2; No), the leakage determination unit 41 determines that the refrigerant has leaked into the outdoor space 3, and the processing is performed in step S2. The process proceeds to S5.

In step S 5, the leakage determination unit 41 determines whether or not the refrigerant leakage is detected by the refrigerant pressure detection device 6 provided in the refrigerant pipe 30 connected to the indoor unit 20. When it is determined that the refrigerant leakage is detected by the refrigerant pressure detection device 6 (step S5; Yes), the process proceeds to step S6.

Note that detection of refrigerant leakage by the refrigerant pressure detection device 6 can be performed based on, for example, fluctuations in the pressure of the refrigerant in the refrigerant pipe 30. Specifically, when the pressure indicated by the detection result of each refrigerant pressure detection device 6 is compared with the pressure determination value P, and the pressure of the refrigerant pressure detection device 6 is lower than the pressure determination value P, It can be determined that the refrigerant has leaked.

In step S6, the shutoff valve control unit 43 performs control so that the target coolant shutoff valve 7 is closed. In this case, the leakage determination unit 41 determines that the refrigerant has leaked from the surrounding refrigerant pipe 30 where the refrigerant pressure detection device 6 showing a pressure lower than the pressure determination value P is installed. And the cutoff valve control part 43 is controlled to close the refrigerant cutoff valve 7 of the refrigerant | coolant piping 30 in which the said refrigerant | coolant pressure detection apparatus 6 was installed. Specifically, in the example illustrated in FIG. 2, for example, when refrigerant leakage is detected by the refrigerant pressure detection device 6 a, the cutoff valve control unit 43 controls to close the refrigerant cutoff valve 7 c.

Next, in step S 7, the leak location determination unit 44 specifies the leak location of the refrigerant in the refrigerant pipe 30. The method of identifying the refrigerant location at this time is the same as that in step S4 described above.

On the other hand, when it is determined in step S5 that there is no refrigerant leakage detected by the refrigerant pressure detection device 6 provided in the refrigerant pipe 30 connected to the indoor unit 20 (step S5; No), the process is performed. The process proceeds to step S8.

In step S8, the shutoff valve control unit 43 performs control so that the target coolant shutoff valve 7 is closed. The refrigerant leakage at this time is not from the refrigerant pipe 30 connected to the indoor unit 20, and it is difficult to specify the leakage location. Therefore, the shutoff valve control unit 43 performs control so as to close the coolant shutoff valve 7 provided in the refrigerant pipe 30 connected to the outdoor unit 10 in order to prevent further refrigerant leakage.

As described above, the air-conditioning apparatus 1 according to Embodiment 1 is configured such that a refrigerant circuit is formed by connecting the outdoor unit 10 and the plurality of indoor units 20 with the refrigerant pipe 30 and circulating the refrigerant. Yes, a refrigerant leak detection device 8 that is provided in the indoor space 4 and detects refrigerant leakage to the indoor space 4, and a plurality of refrigerant pressures that are provided in the refrigerant pipe 30 and detect the pressure of the refrigerant flowing through the refrigerant pipe 30. A detection device 6, a refrigerant shut-off valve 7 that is provided in the refrigerant pipe 30 and allows or blocks the flow of the refrigerant, and a control device 40 that controls opening and closing of the refrigerant shut-off valve 7 are provided. And the control apparatus 40 judges the presence or absence of the leakage of a refrigerant | coolant based on the detection result of the refrigerant | coolant leakage detection apparatus 8 or the refrigerant | coolant pressure detection apparatus 6, and closes the refrigerant | coolant cutoff valve 7 when it is judged that the refrigerant | coolant leaked. The refrigerant leakage point is specified based on the fluctuation of the refrigerant pressure in the refrigerant pipe 30 detected by the refrigerant pressure detection device 6.

Thus, since it is controlled to close the refrigerant shutoff valve 7 when it is determined that the refrigerant has leaked, it is possible to prevent the refrigerant from further leaking. Further, based on the change in the pressure of the refrigerant in the refrigerant pipe 30 detected by the refrigerant pressure detection device 6, the leakage point of the refrigerant can be easily identified. And since the leak location of a refrigerant | coolant can be specified easily in this way, not only the safety | security of the air conditioning apparatus 1 but construction property, economical efficiency, and the convenience can be improved.

Embodiment 2. FIG.
Next, an air conditioner according to Embodiment 2 will be described. The air conditioning apparatus according to Embodiment 2 is a cooling / heating simultaneous type air conditioning apparatus in which a plurality of indoor units can perform both cooling operation and heating operation at the same time.

[Installation example of air conditioner]
FIG. 5 is a schematic diagram illustrating an installation example of the air-conditioning apparatus 1 according to the second embodiment. As shown in FIG. 5, the air conditioner 1 includes an outdoor unit 10 installed in the outdoor space 3, a plurality of indoor units 20 installed in the indoor space 4, and between the outdoor unit 10 and the indoor unit 20. And a branch unit 50 interposed therebetween. The outdoor unit 10 and the branch unit 50 are connected by two refrigerant pipes 30a. In addition, each of the branch unit 50 and the plurality of indoor units 20 is connected by a refrigerant pipe 30b.

In addition, in the following description, the same code | symbol is attached | subjected about the part similar to Embodiment 1 mentioned above, and description is abbreviate | omitted.

The branch unit 50 is configured as a housing different from the outdoor unit 10 and the indoor unit 20 so that it can be installed in a position different from the outdoor space 3 and the indoor space 4, for example, the space 5. The branch unit 50 is connected to the outdoor unit 10 through the refrigerant pipe 30a, and is connected to the indoor unit 20 through the refrigerant pipe 30b. The branch unit 50 is for transmitting the cold heat or the heat generated by the outdoor unit 10 to the indoor unit 20.

The refrigerant pressure detection device 6 and the refrigerant cutoff valve 7 are provided in the

refrigerant pipes

30a and 30b, respectively. Further, similarly to the first embodiment, a refrigerant leak detection device 8 is installed in the indoor space 4.

[Circuit configuration of air conditioner]
FIG. 6 is a schematic diagram illustrating an example of a circuit configuration of the air-conditioning apparatus 1 according to the second embodiment. In the example of FIG. 6, the case where the air conditioning apparatus 1 is comprised with the one outdoor unit 10, the branch unit 50, and the two

indoor units

20A and 20B is shown.

(Outdoor unit)
The outdoor unit 10 includes a compressor 11, a refrigerant flow switching device 12, a heat source side heat exchanger 13, an accumulator 14, and four check valves 15a to 15d.

The check valves 15a to 15d allow the flow of the refrigerant flowing through the refrigerant pipe 30a only in a predetermined direction. The check valve 15a is provided in the refrigerant pipe 30a between the branch unit 50 and the refrigerant flow switching device 12, and from the branch unit 50 to the outdoor unit 10 during the cooling operation including the cooling only operation and the cooling main operation described later. Circulate in the direction of The check valve 15 b is provided in the first connection pipe 31 a that connects the two refrigerant pipes 30 a, and the refrigerant returned from the branch unit 50 during the heating operation including the all heating operation and the heating main operation is supplied to the compressor 11. Distribute to the suction side.

The check valve 15c is provided in the second connection pipe 31b that connects the two refrigerant pipes 30a, and causes the refrigerant discharged from the compressor 11 to flow through the branch unit 50 during the heating operation. The check valve 15d is provided in the refrigerant pipe 30a between the heat source side heat exchanger 13 and the branch unit 50, and causes the refrigerant to flow in the direction from the outdoor unit 10 to the branch unit 50 during the cooling operation.

(Branch unit)
The branch unit 50 has a function of supplying the cold or hot energy supplied from the outdoor unit 10 to the indoor unit 20. The branch unit 50 includes a gas-liquid separator 51, a flow path switching valve 54, a throttle device 52, and a throttle device 53. Note that the number of flow path switching valves 54A and 54B corresponding to the number of indoor units 20 connected to the branch unit 50 is provided.

The flow path switching valves 54A and 54B switch the flow of refrigerant supplied to the indoor unit 20. By switching the refrigerant flow path using the flow path switching valves 54A and 54B, the

indoor units

20A and 20B connected to the branch unit 50 can simultaneously perform the cooling operation and the heating operation. The flow path switching valves 54A and 54B are constituted by, for example, three-way valves.

One of the flow path switching valves 54A is connected to the refrigerant pipe 30a, the other is connected to the gas-liquid separator 51, and the other is connected to the use side heat exchanger 22A of the indoor unit 20A. One of the flow path switching valves 54B is connected to the refrigerant pipe 30a, the other is connected to the gas-liquid separator 51, and the other is connected to the use side heat exchanger 22B of the indoor unit 20B. The flow switching valves 54A and 54B are controlled by the control device 40 to open and close the valves.

The gas-liquid separator 51 is connected to the refrigerant pipe 30a and to each of the inflow / outflow sides of the indoor unit 20. The gas-liquid separator 51 has a function of separating the inflowing refrigerant into a gas refrigerant and a liquid refrigerant.

The expansion device 52 is provided between the gas-liquid separator 51 and the expansion device 21A of the indoor unit 20A and the expansion device 21B of the indoor unit 20B, and expands the refrigerant by decompressing it. The expansion device 53 is provided in a connection pipe connecting the refrigerant pipe 30a and the expansion device 52, the expansion device 21A of the indoor unit 20A, and the expansion device 21B of the indoor unit 20B, and depressurizes the refrigerant. Inflate. The expansion device 52 and the expansion device 53 are configured by, for example, valves, capillaries, and the like capable of controlling the opening degree, such as an electronic expansion valve. When the expansion device 52 and the expansion device 53 are expansion valves, the valve opening degree is controlled by the control device 40.

Refrigerant pressure detection devices 6A and 6B are provided in the refrigerant pipe 30b that connects the branch unit 50 and the indoor unit 20. The refrigerant pressure detection device 6A is provided between the expansion device 52 of the branch unit 50 and the indoor unit 20A in the refrigerant pipe 30b. The refrigerant pressure detection device 6B is provided between the expansion device 52 of the branch unit 50 and the indoor unit 20B in the refrigerant pipe 30b.

A refrigerant pressure detection device 6C is provided in the refrigerant pipe 30a connecting the outdoor unit 10 and the branch unit 50. The refrigerant pressure detection device 6 C is provided between the check valve 15 d in the outdoor unit 10 and the gas-liquid separator 51 in the branch unit 50.

In addition, the installation position and the number of installation of the refrigerant pressure detection device 6 are not limited to this example. For example, the length of the

refrigerant pipes

30a and 30b, the handling of the pipe when installing the branch unit 50 and the indoor unit 20, and the pipe joint It can be determined according to the installation position, the necessary amount of refrigerant, and the like.

In addition, refrigerant shut-off valves 7a to 7d are provided in the refrigerant pipe 30b connecting the branch unit 50 and the indoor unit 20. Refrigerant shut-off

valves

7e and 7f are provided in the refrigerant pipe 30a that connects the outdoor unit 10 and the branch unit 50.

The refrigerant shut-off valve 7e is provided between the check valve 15d of the outdoor unit 10 and the gas-liquid separator 51 of the branch unit 50 in the refrigerant pipe 30a. The refrigerant shut-off valve 7f is provided between the flow path switching valve 54B of the branch unit 50 and the check valve 15a of the outdoor unit 10 in the refrigerant pipe 30a.

These refrigerant shut-off valves 7a to 7f are controlled to open and close by the control device 40, and are in an “open” state in a normal state. Then, when a refrigerant leak is detected, the refrigerant shut-off valves 7a to 7f are brought into a “closed” state based on the control of the control device 40.

When the

refrigerant shutoff valves

7e and 7f are in the “closed” state, the branch unit 50 and the indoor unit 20A are disconnected from the outdoor unit 10 and can be made independent of the air conditioner 1.

Note that any one of the refrigerant shut-off

valves

7e and 7f can be used as long as it has a function of shutting off the refrigerant circuit, similarly to the refrigerant shut-off valves 7a to 7d. Moreover, the installation position and the number of installation of the refrigerant shut-off valve 7 are not limited to this example. For example, the length of the

refrigerant pipes

30a and 30b, the handling of the pipe when installing the branch unit 50 and the indoor unit 20, and the installation of the pipe joint It can be determined according to the position, the necessary amount of refrigerant, and the like.

[Configuration of control device]
FIG. 7 is a block diagram showing an example of the configuration of the control device 40 of FIG. As shown in FIG. 7, the control device 40 includes a leak determination unit 41, a pressure comparison unit 42, a shut-off valve control unit 43, a leak location determination unit 44, and a flow path switching valve control unit 45. In addition, about the control apparatus 40 in this example, only the part relevant to this Embodiment 2 is illustrated, and illustration is abbreviate | omitted about the other part. Further, description of portions common to the above-described first embodiment will be omitted.

The leakage determination unit 41 determines whether or not refrigerant leakage has occurred based on information indicated by the detection signal received from the refrigerant leakage detection device 8 or information indicating a comparison result from the pressure comparison unit 42 described later. The leakage determination unit 41 supplies information indicating the determination result to the cutoff valve control unit 43 and the flow path switching valve control unit 45.

The flow path switching valve control unit 45 receives information indicating the determination result by the leakage determination unit 41, and controls opening / closing of the flow path switching valve 54 of the branch unit 50 based on this information.

[Operation of air conditioner]
Next, the refrigerant | coolant operation | movement in the various operation modes in the air conditioning apparatus 1 which has the said structure is demonstrated. As an operation mode in the air conditioner 1 according to Embodiment 2, in addition to the cooling only operation mode and the heating only operation mode described in Embodiment 1, the

indoor units

20A and 20B are both in the cooling operation and the heating operation. There are a cooling main operation mode and a heating main operation mode in which one of the operations is performed at the same time. Here, the operation of the refrigerant in the cooling only operation mode, the heating only operation mode, the cooling main operation mode, and the heating main operation mode in the air conditioner 1 will be described.

(Cooling mode only)
First, the operation of the refrigerant in the cooling only operation mode will be described. In the all-cooling operation mode, both the

indoor units

20A and 20B perform the cooling operation.

In the cooling only operation mode, the refrigerant flow switching device 12 in the outdoor unit 10 is switched to the state indicated by the solid line in FIG. The low-temperature and low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature and high-pressure gas refrigerant.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the heat source side heat exchanger 13 via the refrigerant flow switching device 12. The high-temperature and high-pressure gas refrigerant that has flowed into the heat source side heat exchanger 13 condenses while exchanging heat with the outdoor air and dissipates heat, and flows out of the heat source side heat exchanger 13 as a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant that has flowed out of the heat source side heat exchanger 13 flows out of the outdoor unit 10 through the check valve 15 d and flows into the branch unit 50. The high-pressure liquid refrigerant that has flowed into the branch unit 50 flows out of the branch unit 50 via the gas-liquid separator 51 and the expansion device 52, and flows into the

indoor units

20A and 20B.

The high-pressure liquid refrigerant that has flowed into the indoor unit 20A is decompressed and expanded by the expansion device 21A to become a low-pressure gas-liquid two-phase refrigerant or liquid refrigerant, and flows into the use-side heat exchanger 22A. The low-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed into the use-side heat exchanger 22A exchanges heat with the room air to absorb heat and evaporate, thereby cooling the room air and becoming a low-pressure gas refrigerant. It flows out of the exchanger 22A.

Also, the high-pressure liquid refrigerant that has flowed into the indoor unit 20B is decompressed and expanded by the expansion device 21B, becomes a low-pressure gas-liquid two-phase refrigerant or liquid refrigerant, and flows into the use-side heat exchanger 22B. The low-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed into the use side heat exchanger 22B exchanges heat with the room air to absorb heat and evaporate, thereby cooling the room air and becoming a low pressure gas refrigerant. It flows out of the exchanger 22B.

The low-pressure gas refrigerant that has flowed out of the use-side heat exchanger 22A flows out of the branch unit 50 via the flow path switching valve 54A and flows into the outdoor unit 10. The low-pressure gas refrigerant that has flowed out of the use-side heat exchanger 22B flows out of the branch unit 50 through the flow path switching valve 54B, and flows out of the branch unit 50 through the flow path switching valve 54A. And flows into the outdoor unit 10.

The low-pressure gas refrigerant that has flowed into the outdoor unit 10 passes through the check valve 15a, the refrigerant flow switching device 12, and the accumulator 14, and is sucked into the compressor 11. Thereafter, the above-described circulation is repeated.

(All heating operation mode)
Next, the operation of the refrigerant in the heating only operation mode will be described. In the all heating operation mode, both the

indoor units

20A and 20B perform the heating operation.

In the heating only operation mode, the refrigerant flow switching device 12 in the outdoor unit 10 is switched to the state indicated by the dotted line in FIG. The low-temperature and low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature and high-pressure gas refrigerant.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows out of the outdoor unit 10 through the refrigerant flow switching device 12 and the check valve 15c, and flows into the branch unit 50. The high-temperature and high-pressure gas refrigerant that has flowed into the branch unit 50 flows out of the branch unit 50 via the gas-liquid separator 51 and the flow path switching valves 54A and 54B, and flows into the

indoor units

20A and 20B.

The high-temperature and high-pressure gas refrigerant that has flowed into the indoor unit 20A flows into the use-side heat exchanger 22A, heats the indoor air and condenses while radiating heat, thereby heating the indoor air and becomes a high-pressure liquid refrigerant. It flows out of the use side heat exchanger 22A. The high-pressure liquid refrigerant flowing out from the use side heat exchanger 22A is decompressed and expanded by the expansion device 21A to become a low-pressure gas-liquid two-phase refrigerant or liquid refrigerant, and flows out from the indoor unit 20A.

Further, the high-temperature and high-pressure gas refrigerant that has flowed into the indoor unit 20B flows into the use-side heat exchanger 22B, heats the indoor air and condenses while dissipating heat, thereby heating the indoor air, And flows out from the use side heat exchanger 22B. The high-pressure liquid refrigerant that has flowed out of the use-side heat exchanger 22B is decompressed and expanded by the expansion device 21B, becomes a low-pressure gas-liquid two-phase refrigerant or liquid refrigerant, and flows out of the indoor unit 20B.

The low-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed out of the

indoor units

20A and 20B flows into the branch unit 50, flows out of the branch unit via the expansion device 53, and flows into the outdoor unit 10.

The low-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed into the outdoor unit 10 flows into the heat source side heat exchanger 13 through the check valve 15b. The low-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed into the heat source side heat exchanger 13 exchanges heat with outdoor air, absorbs heat and evaporates, and becomes a low-temperature and low-pressure gas refrigerant and flows out of the heat source side heat exchanger 13. .

The low-temperature and low-pressure gas refrigerant flowing out from the heat source side heat exchanger 13 passes through the refrigerant flow switching device 12 and the accumulator 14 and is sucked into the compressor 11. Thereafter, the above-described circulation is repeated.

(Cooling operation mode)
Next, the operation of the refrigerant in the cooling main operation mode will be described. Here, the case where the indoor unit 20A performs the cooling operation and the indoor unit 20B performs the heating operation will be described as an example.

In the cooling main operation mode, the refrigerant flow switching device 12 in the outdoor unit 10 is switched to the state shown by the solid line in FIG. The low-temperature and low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature and high-pressure gas refrigerant.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the heat source side heat exchanger 13 via the refrigerant flow switching device 12. The high-temperature and high-pressure gas refrigerant that has flowed into the heat-source-side heat exchanger 13 is condensed while radiating heat by exchanging heat with outdoor air, and becomes a high-pressure gas-liquid two-phase refrigerant and flows out from the heat-source-side heat exchanger 13.

The high-pressure gas-liquid two-phase refrigerant that has flowed out of the heat source side heat exchanger 13 flows out of the outdoor unit 10 through the check valve 15d and flows into the branch unit 50. The high-pressure gas-liquid two-phase refrigerant that has flowed into the branch unit 50 flows into the gas-liquid separator 51 and is separated into a high-pressure gas refrigerant and a high-pressure liquid refrigerant.

The high-pressure gas refrigerant separated by the gas-liquid separator 51 flows out of the branch unit 50 via the flow path switching valve 54B and flows into the indoor unit 20B. The high-pressure gas refrigerant that has flowed into the indoor unit 20B flows into the use-side heat exchanger 22B, heats the indoor air and condenses while dissipating heat, thereby heating the indoor air and using it as a high-pressure liquid refrigerant. It flows out from the side heat exchanger 22B. The high-pressure liquid refrigerant that has flowed out of the use-side heat exchanger 22B is decompressed and expanded by the expansion device 21B, becomes an intermediate-pressure gas-liquid two-phase refrigerant or liquid refrigerant, and flows out of the indoor unit 20B.

Meanwhile, the high-pressure liquid refrigerant separated by the gas-liquid separator 51 and the intermediate-pressure gas-liquid two-phase refrigerant or liquid refrigerant flowing out of the indoor unit 20B flow out of the branch unit 50 and flow into the indoor unit 20A. The high-pressure liquid refrigerant that has flowed into the indoor unit 20A and the intermediate-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed out of the indoor unit 20B are decompressed and expanded by the expansion device 21A to be low-pressure gas-liquid two-phase refrigerant or liquid refrigerant. And flows into the use side heat exchanger 22A.

The low-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed into the use-side heat exchanger 22A exchanges heat with the room air to absorb heat and evaporate, thereby cooling the room air and becoming a low-pressure gas refrigerant. It flows out of the exchanger 22A. The low-pressure gas refrigerant that has flowed out of the use-side heat exchanger 22A flows out of the branch unit 50 via the flow path switching valve 54A and flows into the outdoor unit 10.

(Heating main operation mode)
Next, the operation of the refrigerant in the heating main operation mode will be described. Here, as in the cooling main operation mode, an example will be described in which the indoor unit 20A performs the cooling operation and the indoor unit 20B performs the heating operation.

In the heating main operation mode, the refrigerant flow switching device 12 in the outdoor unit 10 is switched to the state indicated by the dotted line in FIG. The low-temperature and low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature and high-pressure gas refrigerant.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows out of the outdoor unit 10 through the refrigerant flow switching device 12 and the check valve 15c, and flows into the branch unit 50. The high-temperature and high-pressure gas refrigerant that has flowed into the branch unit 50 flows out of the branch unit 50 via the gas-liquid separator 51 and the flow path switching valve 54B.

The high-temperature and high-pressure gas refrigerant that has flowed out of the branch unit 50 flows into the indoor unit 20B. The high-temperature and high-pressure gas refrigerant that has flowed into the indoor unit 20B flows into the use-side heat exchanger 22B, heats the indoor air and condenses while dissipating heat, thereby heating the indoor air and becomes a high-pressure liquid refrigerant. It flows out from the use side heat exchanger 22B. The high-pressure liquid refrigerant that has flowed out of the use-side heat exchanger 22B is decompressed and expanded by the expansion device 21B, becomes an intermediate-pressure gas-liquid two-phase refrigerant or liquid refrigerant, and flows out of the indoor unit 20B.

The intermediate-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed out of the indoor unit 20B flows into the indoor unit 20A. The intermediate-pressure gas-liquid two-phase refrigerant or liquid refrigerant that has flowed into the indoor unit 20A is decompressed and expanded by the expansion device 21A to become a low-pressure gas-liquid two-phase refrigerant or liquid refrigerant, and flows into the use-side heat exchanger 22A.

The low-pressure gas refrigerant that has flowed into the outdoor unit 10 flows into the heat source side heat exchanger 13 through the check valve 15b. The low-pressure gas refrigerant that has flowed into the heat source-side heat exchanger 13 exchanges heat with outdoor air, absorbs heat and evaporates, and becomes a low-temperature and low-pressure gas refrigerant that flows out of the heat source-side heat exchanger 13.

In the second embodiment as well, as in the first embodiment, the air conditioner 1 supplies the refrigerant to the use side heat exchanger 22 of the indoor unit 20 when the indoor temperature reaches the set temperature. It stops, and it switches to the ventilation operation mode by the air blower attached to the utilization side heat exchanger 22. FIG.

[Refrigerant leak detection processing]
Next, processing when refrigerant leakage occurs will be described. FIG. 8 is a flowchart illustrating an example of the flow of the refrigerant leakage detection process in the air-conditioning apparatus 1 according to Embodiment 2. Here, the case where the leakage of the refrigerant is detected in a state where the operation of the air conditioner 1 is stopped will be described. In the following description, the same processes as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

When it is determined that the refrigerant leakage is detected by the refrigerant leakage detection device 8 (step S2; Yes), the leakage determination unit 41 determines that the refrigerant has leaked into the indoor space 4, and the process proceeds to step S3. To do. In step S3, the shutoff valve control unit 43 of the control device 40 includes the coolant shutoff valve 7 of the refrigerant pipe 30 connected to all the indoor units 20 installed in the indoor space 4, and the coolant shutoff valve 7 on the upstream side thereof. Is controlled to close.

Next, in step S 4, the leakage location determination unit 44 of the control device 40 identifies the location of refrigerant leakage in the refrigerant piping 30 based on the pressure and the pressure determination value P by each refrigerant pressure detection device 6.

In step S6, the shut-off valve control unit 43 performs control so as to close the refrigerant shut-off valve 7 of the refrigerant pipe 30 provided with the refrigerant pressure detection device 6 that exhibits a pressure lower than the pressure determination value P. Here, for example, when the refrigerant leakage is detected by the refrigerant pressure detection device 6C shown in FIG. 6, the cutoff valve control unit 43 controls the refrigerant cutoff valve 7e installed in the refrigerant pipe 30a to be closed. At this time, the shutoff valve control unit 43 can prevent further refrigerant leakage by controlling so as to close the refrigerant shutoff valve 7 installed in the refrigerant pipe 30b.

Next, in step S 11, the flow path switching valve control unit 45 of the control device 40 is connected to the indoor unit 20 connected to the refrigerant pipe 30 in which the refrigerant pressure detection device 6 that detects refrigerant leakage is installed in the branch unit 50. Control is performed so that the corresponding flow path switching valve 54 is closed. Thereby, further refrigerant leakage can be prevented.

And in step S7, the leak location determination part 44 specifies the leak location of the refrigerant | coolant in the refrigerant | coolant piping 30 similarly to step S4 mentioned above.

In step S8, the shutoff valve control unit 43 controls the refrigerant shutoff valve 7 provided in the refrigerant pipe 30 connected to the outdoor unit 10 to be closed in order to prevent further refrigerant leakage.

As described above, the air-conditioning apparatus 1 according to the second embodiment has a gas-liquid separator 51 that separates the refrigerant supplied from the outdoor unit 10 into a gas refrigerant and a liquid refrigerant, as compared with the first embodiment. And a branch unit 50 having a plurality of flow path switching valves 54 for switching the flow of refrigerant supplied to the plurality of indoor units 20, and being interposed between the outdoor unit 10 and the plurality of indoor units 20. The device 40 controls to close the flow path switching valve 54 when it is determined that the refrigerant has leaked. Thereby, when a refrigerant | coolant leaks, it can suppress that a refrigerant | coolant leaks further.

Embodiment 3 FIG.
Next, an air conditioner according to Embodiment 3 will be described. In the third embodiment, a plurality of refrigerant pressure detection devices 6 and a plurality of refrigerant shut-off valves 7 are further installed in the air conditioner 1 according to the first embodiment described above.

[Installation example of air conditioner]
FIG. 9 is a schematic diagram illustrating an installation example of the air-conditioning apparatus 1 according to the third embodiment. As shown in FIG. 9, the air conditioner 1 includes an outdoor unit 10 and a plurality of indoor units 20 as in the first embodiment.

In the third embodiment, in addition to the refrigerant pressure detection device 6a and the refrigerant pressure detection device 6b described in the first embodiment, the refrigerant pressure detection device 6c and the refrigerant provided on the outdoor unit 10 side in the refrigerant pipe 30 A pressure detection device 6d is provided.

Further, in the third embodiment, in addition to the refrigerant cutoff valves 7a to 7d described in the first embodiment, the refrigerant cutoff valves 7g to 7j are provided. The refrigerant cutoff valve 7g and the refrigerant cutoff valve 7h are provided in a pipe between the indoor unit 20A and the indoor unit 20B in the refrigerant pipe 30. The refrigerant shut-off

valves

7 i and 7 j are provided in the pipe on the outdoor unit 10 side in the refrigerant pipe 30.

Thus, by providing more refrigerant pressure detectors 6 and refrigerant shutoff valves 7 as compared with the first embodiment, it is possible to more reliably detect refrigerant leakage and to easily identify the leakage location. it can.

In addition, the installation position and the number of installation of the refrigerant pressure detection device 6 and the refrigerant cutoff valve 7 are not limited to this example. For example, the length of the refrigerant pipe 30a and the refrigerant pipe 30b, the branch unit 50, and the indoor unit 20 are installed. It can be determined according to the handling of the pipe, the installation position of the pipe joint, the required amount of refrigerant, and the like.

As described above, the air conditioner 1 according to the third embodiment is provided with more refrigerant pressure detection devices 6 and refrigerant shut-off valves 7 in the refrigerant pipe 30 than in the first embodiment. It can be identified more easily.

1 air conditioner, 2 building, 3 outdoor space, 4 indoor space, 5 space, 6, 6A, 6B, 6C, 6a, 6b, 6c, 6d refrigerant pressure detecting device, 7, 7a, 7b, 7c, 7d, 7e 7f, 7g, 7h, 7i, 7j Refrigerant shut-off valve, 8 Refrigerant leak detection device, 10 Outdoor unit, 11 Compressor, 12 Refrigerant flow path switching device, 13 Heat source side heat exchanger, 14 Accumulator, 15a, 15b, 15c , 15d check valve, 20, 20A, 20B indoor unit, 21, 21A, 21B throttle device, 22, 22A, 22B use side heat exchanger, 30, 30a, 30b refrigerant piping, 31a first connection piping, 31b first 2 connection pipes, 35a, 35b branch point, 40 control device, 41 leak judgment unit, 42 pressure comparison unit, 43 shutoff valve control unit, 44 leak location judgment unit, 4 Channel switching valve control unit, 50 branch unit, 51 gas-liquid separator, 52, 53 expansion device, 54 and 54A, 54B the flow path switching valve.

Claims

An air conditioner in which a refrigerant circuit is formed by connecting an outdoor unit and a plurality of indoor units with a refrigerant pipe and circulating the refrigerant,
A refrigerant leakage detection device that is provided in the air conditioning target space and detects leakage of the refrigerant to the air conditioning target space;
A plurality of refrigerant pressure detection devices that are provided in the refrigerant pipe and detect the pressure of the refrigerant flowing through the refrigerant pipe;
A refrigerant shut-off valve provided in the refrigerant pipe and allowing or blocking the flow of the refrigerant;
A control device for controlling opening and closing of the refrigerant shut-off valve,
The control device includes:
Based on the detection result of the refrigerant leakage detection device or the refrigerant pressure detection device, the presence or absence of leakage of the refrigerant is determined, and when it is determined that the refrigerant has leaked, the refrigerant shut-off valve is controlled to be closed,
An air conditioner that identifies a leakage location of the refrigerant based on a change in pressure of the refrigerant in the refrigerant pipe detected by the refrigerant pressure detection device.
The refrigerant pressure detection device and the refrigerant cutoff valve are:
The air conditioning apparatus according to claim 1, wherein the air conditioner is provided at a position in the refrigerant pipe connecting the outdoor unit and the plurality of indoor units.
The control device includes:
When the refrigerant leakage is detected by the detection result of the refrigerant leakage detection device, the pressure detected by the refrigerant pressure detection device is compared with a reference pressure determination value,
3. The method according to claim 1, wherein when the pressure detected by the refrigerant pressure detection device is lower than the pressure determination value, it is determined that the refrigerant has leaked near a position where the refrigerant pressure detection device is provided. Air conditioner.
The control device includes:
Comparing the pressure detected by the refrigerant pressure detection device with a reference pressure judgment value;
When the detected pressure is lower than the pressure determination value, it is determined that the refrigerant has leaked,
The air conditioning apparatus according to claim 1 or 2, wherein it is determined that the refrigerant has leaked in a vicinity of a position where the refrigerant pressure detection device that detects a pressure lower than the pressure determination value is provided.
The pressure judgment value is
Of the saturation pressure of the refrigerant calculated based on the temperature of the outdoor space or the saturation pressure of the refrigerant calculated based on the temperature of the air conditioning target space, whichever is the lower saturation pressure or the average value of the two saturation pressures The air conditioning apparatus according to claim 3 or 4.
A gas-liquid separator that separates the refrigerant supplied from the outdoor unit into a gas refrigerant and a liquid refrigerant;
A plurality of flow path switching valves for switching the flow of the refrigerant supplied to the plurality of indoor units,
A branching unit interposed between the outdoor unit and the plurality of indoor units;
The control device includes:
The air conditioner according to any one of claims 1 to 5, wherein when it is determined that the refrigerant has leaked, the flow path switching valve is controlled to close.