Refrigeration cycle device and refrigerant leakage detection system

Abstract

To solve a problem that in a conventional refrigeration cycle device, refrigerant leakage is determined on the basis of a change of pressure or a temperature during stop of a refrigeration cycle and accuracy of this determination method is poor.SOLUTION: An air conditioner 1 includes a heat source unit 2 and a utilization unit 4, and has a refrigerant circuit 10, first detection sections 28, 29, 30, 31, 43, 44 and a control section 70. In the refrigerant circuit 10, a compressor 21, a condenser, an expansion mechanism 35 and an evaporator are connected by refrigerant piping. The first detection sections 28, 29, 30, 31, 43, 44 detect a temperature or pressure of a refrigerant in the refrigerant circuit 10. The control section 70 starts the compressor 21 during stop of the operation of the compressor 21, and executes a determination mode of determining presence / absence of refrigerant leakage from the refrigerant circuit 10, on the basis of detection values from the first detection sections 28, 29, 30, 31, 43, 44.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a refrigeration cycle device and a refrigerant leakage determination system. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in a refrigeration cycle device, a method is known in which a refrigerant leak is determined based on a change in pressure or temperature while the refrigeration cycle is stopped (Patent Document 1 (Japanese Patent No. 6257801)). Summary of the Invention [Problem to be solved by the invention]

[0003] However, this determination method has a problem of low accuracy. [Means for solving the problem]

[0004] A refrigeration cycle apparatus according to a first aspect is a refrigeration cycle apparatus having a heat source unit and a utilization unit, and includes a refrigerant circuit, a first detection unit, and a control unit. The refrigerant circuit includes a compressor, a condenser, an expansion mechanism, and an evaporator, which are connected by refrigerant piping. The first detection unit detects the temperature or pressure of the refrigerant in the refrigerant circuit. The control unit starts the compressor while the compressor is not operating, and executes a determination mode in which the control unit determines whether or not there is a refrigerant leak from the refrigerant circuit based on the detection value of the first detection unit.

[0005] Conventional methods for determining the presence or absence of refrigerant leakage based on changes in refrigerant pressure or temperature while the system is stopped have a problem of poor accuracy. In contrast, the refrigeration cycle device of the present disclosure starts the compressor while the compressor is stopped to determine the presence or absence of refrigerant leakage, allowing for highly accurate determination of refrigerant leakage.

[0006] A refrigeration cycle apparatus according to a second aspect is the apparatus according to the first aspect, wherein the control unit executes the determination mode when the compressor has not been operated for a predetermined time.

[0007] In this refrigeration cycle apparatus, when the compressor has not been operated for a predetermined period of time, for example, even during seasons when the refrigeration cycle apparatus is used less frequently, it is possible to accurately determine whether or not there is a refrigerant leak.

[0008] A refrigeration cycle apparatus according to a third aspect is the apparatus according to the first or second aspect, wherein the refrigeration cycle apparatus is an air conditioner.

[0009] A refrigeration cycle apparatus according to a fourth aspect is the apparatus according to the third aspect, in which the utilization unit has a utilization fan. The utilization fan can be set to operate at a rotation speed range between a first rotation speed and a second rotation speed. When executing the determination mode, the control unit operates the utilization fan at a rotation speed equal to or lower than the middle of the first rotation speed and the second rotation speed.

[0010] In this refrigeration cycle device, when the utilization fan is operated to determine whether or not there is a refrigerant leak, even if the air blown out of the utilization unit is not at an appropriate temperature for the people in the room, a decrease in the comfort of the people in the room can be suppressed.

[0011] A refrigeration cycle apparatus according to a fifth aspect is the apparatus according to the third or fourth aspect, further comprising a second detection unit that detects an ambient temperature around the heat source unit or an ambient temperature around the utilization unit. The control unit determines the presence or absence of refrigerant leakage from the refrigerant circuit based on the ambient temperature around the heat source unit or the ambient temperature around the utilization unit.

[0012] In this refrigeration cycle apparatus, refrigerant leakage can be determined with high accuracy based on the outdoor temperature or the indoor temperature in addition to the temperature or pressure of the refrigerant flowing through the refrigerant circuit.

[0013] A refrigeration cycle apparatus according to a sixth aspect is the apparatus according to any one of the third aspect to the fifth aspect, further comprising a human detection sensor that is installed in a first space that is an air-conditioning target of the refrigeration cycle apparatus and detects the presence or absence of a human in the first space. When the human detection sensor determines that no human is present in the first space, the control unit executes a determination mode.

[0014] In this refrigeration cycle apparatus, the refrigeration cycle apparatus is operated when no one is in the room, so that the presence or absence of a refrigerant leak can be determined without affecting the comfort of the user.

[0015] A refrigeration cycle device of a seventh aspect is a device of any one of the third aspect to the sixth aspect, in which the control unit executes a judgment mode when the temperature or thermal index of the first space, which is the target of air conditioning of the refrigeration cycle device, is within a predetermined range.

[0016] In this refrigeration cycle apparatus, by executing the determination mode when the state is comfortable, it is possible to determine the presence or absence of a refrigerant leak while minimizing the effect on the comfort of the user.

[0017] The refrigeration cycle apparatus of an eighth aspect is the apparatus of the third aspect, wherein the utilization unit has a heat exchanger and a utilization fan. The control unit uses the heat exchanger as an evaporator, and after executing the determination mode, stops the compressor and executes a drying operation to dry the heat exchanger with the utilization fan.

[0018] In this refrigeration cycle device, even if the evaporator becomes wet by operating the refrigeration cycle device while the refrigeration cycle device is stopped, the evaporator can be dried by performing a drying operation after the judgment mode ends.

[0019] A refrigeration cycle apparatus of a ninth aspect is the apparatus of any one of the third aspect to the eighth aspect, in which the control unit executes the determination mode simultaneously with a cleaning operation for cleaning the refrigeration cycle apparatus.

[0020] In this refrigeration cycle apparatus, the determination mode can be executed simultaneously with the cleaning operation while the operation of the refrigeration cycle apparatus is stopped.

[0021] A refrigeration cycle apparatus according to a tenth aspect is the apparatus according to any one of the third aspect to the ninth aspect, in which the operating state of the refrigeration cycle apparatus is switchable between a cooling operation and a heating operation, and the control unit executes the determination mode in the operating state of the refrigeration cycle apparatus set before the compressor is stopped.

[0022] In this refrigeration cycle apparatus, in the judgment mode, the refrigeration cycle apparatus is operated in the operating state that has been set for the refrigeration cycle apparatus, so that the judgment mode can be executed while minimizing the effect on the comfort of the user.

[0023] A refrigerant leakage determination system according to an eleventh aspect includes a refrigeration cycle apparatus and a server. The air conditioner is the refrigeration cycle apparatus according to any one of claims 1 to 10. The server accumulates a determination result of a determination mode of the refrigeration cycle apparatus. The control unit transmits the determination result of the determination mode to the server.

[0024] In this refrigerant leakage determination system, the determination result of the determination mode of the refrigeration cycle device can be transmitted to a server, whereby the determination result can be stored. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram of a refrigerant circuit of an air conditioner. [Diagram 2] 10 is a flowchart showing an example of a procedure for executing a determination mode. [Diagram 3] 13 is a flowchart in a determination mode. [Figure 4] FIG. 11 is a schematic refrigerant circuit diagram of an air conditioner according to another embodiment. [Diagram 5] FIG. 11 is a schematic refrigerant circuit diagram of an air conditioner according to another embodiment. [Figure 6] FIG. 2 is a block diagram of an air conditioner remote management system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The refrigeration cycle device of the present disclosure will be described with reference to the drawings.

[0027] (1) Overall structure FIG. 1 is a schematic refrigerant circuit diagram of an air conditioner 1, which is an example of a refrigeration cycle device of the present disclosure. The air conditioner 1 is a device used for heating and cooling the inside of a building or the like by performing a vapor compression refrigeration cycle operation. The air conditioner 1 mainly includes one heat source unit 2, one utilization unit 4, and a liquid refrigerant connection pipe 6 and a gas refrigerant connection pipe 7 that connect the heat source unit 2 and the utilization unit 4. The vapor compression refrigerant circuit 10 of the air conditioner 1 of this embodiment is configured by connecting the heat source unit 2, the utilization unit 4, the liquid refrigerant connection pipe 6 and the gas refrigerant connection pipe 7. The utilization unit does not have to be one, and may be multiple.

[0028] (2) Detailed configuration (2-1) Usage unit The utilization unit 4 is installed by embedding or hanging from the ceiling of an indoor building or the like, or by hanging from an indoor wall surface, etc. The utilization unit 4 is connected to the heat source unit 2 via a liquid refrigerant connection pipe 6 and a gas refrigerant connection pipe 7, and constitutes a part of the refrigerant circuit 10.

[0029] The configuration of the utilization unit 4 will be described.

[0030] The utilization unit 4 mainly includes a utilization side refrigerant circuit 10a that constitutes a part of the refrigerant circuit 10. The utilization side refrigerant circuit 10a mainly includes a utilization side heat exchanger .

[0031] In this embodiment, the user-side heat exchanger 42 is a cross-fin type fin-and-tube heat exchanger composed of a heat transfer tube and a number of fins, and functions as a refrigerant evaporator to cool the indoor air during cooling operation, and functions as a refrigerant condenser to heat the indoor air during heating operation.

[0032] In this embodiment, the utilization unit 4 includes a utilization fan 47 for drawing indoor air into the unit, exchanging heat therein, and then supplying the air indoors as supply air, and is capable of exchanging heat between the indoor air and the refrigerant flowing through the utilization side heat exchanger 42. The utilization fan 47 is a fan capable of varying the flow rate of air supplied to the utilization side heat exchanger 42, and in this embodiment, is a cross-flow fan driven by a fan motor 47a. The utilization fan 47 is operated in a rotation speed range between a first rotation speed (maximum rotation speed) and a second rotation speed (minimum rotation speed). In this embodiment, the first rotation speed of the utilization fan 47 is 800 rpm, and the second rotation speed is 1200 rpm. The control unit 70 can change the air volume of the utilization fan 47 in a stepwise manner. The relationship between the rotation speed and the air volume at each stage is set, for example, as follows: Fan tap L air volume at a rotation speed of 800 rpm, Fan tap LM air volume at a rotation speed of 900 rpm, Fan tap M air volume at a rotation speed of 1000 rpm, Fan tap HM air volume at a rotation speed of 1100 rpm, and Fan tap H air volume at a rotation speed of 1200 rpm. Therefore, Fan tap L has the smallest air volume, and Fan tap H has the largest air volume.

[0033] The utilization unit 4 is also provided with various sensors. A liquid side temperature sensor 43 is provided on the liquid side of the utilization side heat exchanger 42 to detect the temperature of the refrigerant in a liquid state or in a two-phase gas-liquid state. A gas side temperature sensor 44 is provided on the gas side of the utilization side heat exchanger 42 to detect the temperature of the refrigerant in a gas state or in a two-phase gas-liquid state. In this embodiment, the liquid side temperature sensor 43 and the gas side temperature sensor 44 are made of a thermistor. The liquid side temperature sensor 43 and the gas side temperature sensor 44 are an example of a first detection unit in the claims that detects the temperature or pressure of the refrigerant in the refrigerant circuit 10.

[0034] The utilization unit 4 also includes a utilization-side control unit 45 that controls the operation of each part constituting the utilization unit 4. The utilization-side control unit 45 has a microcomputer, memory, and the like provided for controlling the utilization unit 4, and can exchange control signals and the like with a remote control (not shown) for individually operating the utilization unit 4, and can exchange control signals and the like with a heat source control unit 32 of the heat source unit 2, which will be described later. The utilization-side control unit 45 and the heat source-side control unit 32, which will be described later, work together to function as a control unit 70 that controls the operation of each part of the air conditioner 1. The control unit 70 will be described later.

[0035] (2-2) Heat source unit The heat source unit 2 is installed on the roof of a building or the like and is connected to the utilization units 4 via a liquid refrigerant connection pipe 6 and a gas refrigerant connection pipe 7, forming a refrigerant circuit 10 between the utilization units 4.

[0036] Next, a description will be given of the configuration of the heat source unit 2. The heat source unit 2 mainly includes a heat source side refrigerant circuit 10b that constitutes a part of the refrigerant circuit 10. The heat source side refrigerant circuit 10b mainly includes a compressor 21, a four-way switching valve 22, a heat source side heat exchanger 23, an accumulator 24, a liquid side shutoff valve 25, a gas side shutoff valve 26, and an expansion valve 35.

[0037] The compressor 21 is a compressor whose operating capacity can be varied, and in this embodiment, is a positive displacement compressor driven by a motor 21a controlled by an inverter. In this embodiment, the compressor 21 is only one, but is not limited to this, and two or more compressors may be connected in parallel depending on the number of connected utilization units, etc.

[0038] The four-way switching valve 22 is a valve for switching the direction of the refrigerant flow. During cooling operation, the four-way switching valve 22 connects the discharge side of the compressor 21 to the gas side of the heat source side heat exchanger 23, and also connects the suction side of the compressor 21 (specifically, the accumulator 24) to the gas refrigerant connection pipe 7 side (see the solid line of the four-way switching valve 22 in FIG. 1). This allows the heat source side heat exchanger 23 to function as a condenser of the refrigerant compressed in the compressor 21, and the utilization side heat exchanger 42 to function as an evaporator of the refrigerant condensed in the heat source side heat exchanger 23. During heating operation, the four-way switching valve 22 connects the discharge side of the compressor 21 to the gas refrigerant connection pipe 7 side, and also connects the suction side of the compressor 21 to the gas side of the heat source side heat exchanger 23 (see the dashed line of the four-way switching valve 22 in FIG. 1). This allows the utilization side heat exchanger 42 to function as a condenser for the refrigerant compressed in the compressor 21, and the heat source side heat exchanger 23 to function as an evaporator for the refrigerant condensed in the utilization side heat exchanger 42.

[0039] In this embodiment, the expansion valve 35 is an electronic expansion valve with a variable opening that is connected to the liquid side of the heat source side heat exchanger 23 in order to adjust the flow rate of the refrigerant flowing through the liquid refrigerant communication pipe 6, etc.

[0040] In this embodiment, the heat source side heat exchanger 23 is a cross-fin type fin-and-tube heat exchanger composed of a heat transfer tube and a number of fins, and functions as a refrigerant condenser during cooling operation and as a refrigerant evaporator during heating operation. The gas side of the heat source side heat exchanger 23 is connected to the four-way switching valve 22, and the liquid side is connected to the liquid refrigerant connection pipe 6.

[0041] In this embodiment, the heat source unit 2 is equipped with a heat source fan 27 for drawing outdoor air into the unit, supplying it to the heat source side heat exchanger 23, and then discharging it outdoors, and is capable of exchanging heat between the outdoor air and the refrigerant flowing through the heat source side heat exchanger 23. This heat source fan 27 is a fan that can vary the flow rate of air supplied to the heat source side heat exchanger 23, and in this embodiment, is a propeller fan driven by a fan motor 27a.

[0042] The accumulator 24 is connected between the four-way switching valve 22 and the compressor 21, and is a container capable of storing surplus refrigerant generated in the refrigerant circuit 10 depending on the operating load of the utilization unit 4.

[0043] The liquid side shut-off valve 25 and the gas side shut-off valve 26 are valves provided at connection ports to external devices and piping (specifically, the liquid refrigerant connection piping 6 and the gas refrigerant connection piping 7). The liquid side shut-off valve 25 is connected to the heat source side heat exchanger 23 via piping. The gas side shut-off valve 26 is connected to the four-way switching valve 22 via piping.

[0044] In addition, various sensors are provided in the heat source unit 2. Specifically, the heat source unit 2 is provided with a suction pressure sensor 28 that detects the suction pressure of the compressor 21, a discharge pressure sensor 29 that detects the discharge pressure of the compressor 21, a heat exchanger temperature sensor 30 that detects the temperature of the refrigerant flowing in the heat source side heat exchanger 23, and a liquid side temperature sensor 31 that detects the temperature of the refrigerant in a liquid state or a two-phase gas-liquid state on the liquid side of the heat source side heat exchanger 23. The suction pressure sensor 28, the discharge pressure sensor 29, the heat exchanger temperature sensor 30, and the liquid side temperature sensor 31 are a first detection unit in the claims that detects the temperature or pressure of the refrigerant in the refrigerant circuit 10.

[0045] The heat source unit 2 also includes a heat source side control section 32 that controls the operation of each section constituting the heat source unit 2. The heat source side control section 32 includes a microcomputer provided for controlling the heat source unit 2, a memory, an inverter circuit for controlling the motor 21a, and the like, and can exchange control signals and the like with a usage side control section 45 of the usage unit 4. The heat source side control section 32 and the usage side control section 45 work together to function as a control section 70 that controls the operation of each section of the air conditioner 1. The control section 70 will be described later.

[0046] As described above, the user-side refrigerant circuit 10a, the heat-source-side refrigerant circuit 10b, and the refrigerant connection pipes 6 and 7 are connected to configure the refrigerant circuit 10 of the air conditioner 1. The air conditioner 1 of this embodiment operates by switching between cooling operation and heating operation using the four-way switching valve 22, and controls each device of the heat source unit 2 and the user units 4 according to the operating load of the user units 4.

[0047] (2-3) Control section The control unit 70 includes a usage side control unit 45 and a heat source side control unit 32 .

[0048] The control unit 70 controls the operation of the air conditioner 1. For example, the control unit 70 controls the operation of the four-way switching valve 22 to switch to a state in which the heat source side heat exchanger 23 functions as a condenser and the utilization side heat exchanger 42 functions as an evaporator during cooling operation. The control unit 70 also controls the operation of the four-way switching valve 22 to switch to a state in which the heat source side heat exchanger 23 functions as an evaporator and the utilization side heat exchanger 42 functions as a condenser during heating operation. The control unit 70 also adjusts the rotation speed of the fan motor 47a of the utilization fan 47 and the fan motor 27a of the heat source fan 27. The control unit 70 also adjusts the opening degree of the expansion valve 35. The control unit 70 also executes a determination mode in which the presence or absence of refrigerant leakage from the refrigerant circuit 10 is determined based on the detection value of the first detection unit. The control unit 70 starts the compressor 21 while the compressor 21 is stopped, and executes the determination mode. The periods when the compressor 21 is stopped include, for example, a period when no operation signal is input to the air conditioner 1, a period when the heating / cooling load (the temperature difference between the set temperature and the room temperature) becomes small and the compressor 21 stops, which is called a thermo-off state, and a period when the compressor 21 is not operated and the utility fan 47 is operated, which is called a blowing operation state.

[0049] The control unit 70 is realized by a computer. The control unit 70 has a control arithmetic device and a storage device (not shown). A processor such as a CPU can be used as the control arithmetic device. The control arithmetic device reads a program stored in the storage device and performs a predetermined arithmetic process according to the program. Furthermore, the control arithmetic device can write the results of the calculations to the storage device and read information stored in the storage device according to the program. The storage device can be used as a database.

[0050] The control unit 70 also executes the determination mode when the air conditioner 1 has not been operated for a predetermined period of time. In this embodiment, the control unit 70 executes the determination mode once a day.

[0051] (3) Overall operation Next, the operation of the air conditioner 1 of this embodiment will be described.

[0052] The operation modes of the air conditioner 1 in this embodiment include a normal operation mode in which the heat source unit 2 and each device of the utilization unit 4 are controlled according to the operating load of the utilization unit 4, and a determination mode in which the presence or absence of refrigerant leakage from the refrigerant circuit 10 is determined. The normal operation mode includes a cooling operation and a heating operation. In the determination mode of this embodiment, the control unit 70 operates the air conditioner 1 in a cooling operation state, while detecting the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23 functioning as a condenser, and determines the presence or absence of refrigerant leakage from the refrigerant circuit 10.

[0053] (4) Operation of air conditioner in each operation mode The operation of the air conditioner 1 in each operation mode will be described below.

[0054] (4-1) Normal operation mode (4-1-1) Cooling operation First, the cooling operation in the normal operation mode will be described.

[0055] During cooling operation, the four-way switching valve 22 is in a state shown by a solid line in FIG. 1, in other words, the discharge side of the compressor 21 is connected to the gas side of the heat source side heat exchanger 23. The liquid side shutoff valve 25 and the gas side shutoff valve 26 are opened, and the opening degree of the expansion valve 35 is adjusted so that the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23 becomes a predetermined value. In this embodiment, the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23 is detected by converting the discharge pressure value of the compressor 21 detected by the discharge pressure sensor 29 into a saturation temperature value of the refrigerant, and subtracting the refrigerant temperature value detected by the liquid side temperature sensor 31 from the saturation temperature value of the refrigerant. Alternatively, the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23 may be detected by subtracting the refrigerant temperature value detected by the liquid side temperature sensor 31 from the refrigerant temperature value detected by the heat exchange temperature sensor 30 that detects the temperature of the refrigerant flowing in the heat source side heat exchanger 23. When the compressor 21 is started in this state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become high-pressure gas refrigerant. The high-pressure gas refrigerant is then sent to the heat-source-side heat exchanger 23 via the four-way switching valve 22, and exchanges heat with outdoor air supplied by the heat-source fan 27, where it is condensed to become high-pressure liquid refrigerant.

[0056] This high-pressure liquid refrigerant is decompressed by the expansion valve 35 to become a low-pressure refrigerant in a gas-liquid two-phase state. Then, this low-pressure refrigerant in a gas-liquid two-phase state is sent to the user-side heat exchanger 42 via the liquid-side shutoff valve 25 and the liquid refrigerant connection pipe 6, where it exchanges heat with indoor air supplied by the user fan 47 and evaporates to become a low-pressure gas refrigerant.

[0057] Here, the expansion valve 35 controls the flow rate of the refrigerant flowing through the heat source side heat exchanger 23 so that the degree of subcooling at the outlet of the heat source side heat exchanger 23 becomes a predetermined value, and therefore the high-pressure gas refrigerant condensed in the heat source side heat exchanger 23 has a predetermined degree of subcooling. Then, a flow rate of refrigerant flows through the user side heat exchanger 42 according to the operating load required in the air-conditioned space in which the user units 4 are installed.

[0058] This low-pressure gas refrigerant is sent to the heat source unit 2 via the gas refrigerant communication piping 7, and flows into the accumulator 24 via the gas side shut-off valve 26 and the four-way switching valve 22. The low-pressure gas refrigerant that has flowed into the accumulator 24 is then sucked back into the compressor 21. Here, when an excess amount of refrigerant occurs in the refrigerant circuit 10 depending on the operating load of the utilization unit 4, for example, when the utilization unit 4 is stopped or when the operating load of the utilization unit 4 is small, the excess refrigerant is stored in the accumulator 24.

[0059] (4-1-2) Heating operation Next, the heating operation in the normal operation mode will be described.

[0060] During heating operation, the four-way switching valve 22 is in a state shown by a broken line in Fig. 1, in other words, the discharge side of the compressor 21 is connected to the gas side of the utilization side heat exchanger 42, and the suction side of the compressor 21 is connected to the gas side of the heat source side heat exchanger 23. In addition, the liquid side shutoff valve 25 and the gas side shutoff valve 26 are opened, and the opening degree of the expansion valve 35 is adjusted so that the degree of subcooling of the refrigerant at the outlet of the utilization side heat exchanger 42 becomes a predetermined value. In this embodiment, the degree of subcooling of the refrigerant at the outlet of the utilization side heat exchanger 42 is detected by converting the discharge pressure value of the compressor 21 detected by the discharge pressure sensor 29 into the saturation temperature value of the refrigerant, and subtracting the refrigerant temperature value detected by the liquid side temperature sensor 43 from the saturation temperature value of the refrigerant. Although not adopted in this embodiment, a temperature sensor may be provided to detect the temperature of the refrigerant flowing in the use side heat exchanger 42, and the degree of subcooling of the refrigerant at the outlet of the use side heat exchanger 42 may be detected by subtracting the refrigerant temperature value detected by the liquid side temperature sensor 43 from the refrigerant temperature value detected by this temperature sensor.

[0061] When the compressor 21 is started in this state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become high-pressure gas refrigerant. The low-pressure gas refrigerant is then sent to the utilization unit 4 via the four-way switching valve 22, the gas side shut-off valve 26, and the gas refrigerant connection piping 7.

[0062] The high-pressure gas refrigerant sent to the utilization unit 4 exchanges heat with indoor air supplied by the utilization fan 47 in the utilization-side heat exchanger 42, and is condensed to become a high-pressure liquid refrigerant.

[0063] This high-pressure liquid refrigerant is sent to the heat source unit 2 via the liquid refrigerant connection pipe 6, and flows into the expansion valve 35 via the liquid-side shut-off valve 25. This high-pressure liquid refrigerant is decompressed by the expansion valve 35 to become a low-pressure refrigerant in a gas-liquid two-phase state. Here, the expansion valve 35 controls the flow rate of the refrigerant flowing through the user-side heat exchanger 42 so that the degree of subcooling at the outlet of the user-side heat exchanger 42 becomes a predetermined value, so that the high-pressure liquid refrigerant condensed in the user-side heat exchanger 42 has a predetermined degree of subcooling. Then, a flow rate of refrigerant flows through the user-side heat exchanger 42 according to the operating load required in the air-conditioned space in which the user unit 4 is installed.

[0064] This low-pressure refrigerant in a two-phase gas-liquid state flows into the heat source-side heat exchanger 23. The low-pressure refrigerant in a two-phase gas-liquid state that flows into the heat source-side heat exchanger 23 exchanges heat with outdoor air supplied by the heat source fan 27, is condensed, and becomes a low-pressure gas refrigerant, and flows into the accumulator 24 via the four-way switching valve 22. The low-pressure gas refrigerant that flows into the accumulator 24 is sucked into the compressor 21 again. Here, when an excess amount of refrigerant occurs in the refrigerant circuit 10 depending on the operating load of the utilization unit 4, for example, when the utilization unit 4 is stopped or when the operating load of the utilization unit 4 is small, the excess refrigerant is stored in the accumulator 24 in the same manner as during cooling operation.

[0065] (4-2) Judgment mode Next, the determination mode will be described.

[0066] The control unit 70 executes the determination mode at predetermined intervals, for example, once a day.

[0067] When the air conditioner 1 is operated in the normal operation mode, the control unit 70 executes the determination mode between operations in the normal operation mode.

[0068] When the compressor 21 has stopped operating for a long period of time, the control unit 70 forcibly starts the compressor 21 once a day to execute the judgment mode. Cases when the compressor 21 has stopped operating for a long period of time include, for example, not only cases when the air conditioner 1 is stopped, but also cases when the heating / cooling load is small and the compressor 21 is stopped, and cases when the compressor 21 is stopped and only the utility fan 47 is operating. This allows the control unit 70 to reliably execute the judgment mode at predetermined intervals. Here, the procedure by which the control unit 70 executes the judgment mode when the compressor 21 has stopped for a predetermined period of time will be described with reference to the flowchart in FIG. 2.

[0069] First, in step S1, the control unit 70 determines whether the compressor 21 has been stopped for a predetermined time. The predetermined time is appropriately determined, for example, so that the control unit 70 executes the determination mode once a day even if the compressor 21 has been stopped for a long time. For example, if the compressor 21 has been stopped from midnight to 11:30 p.m., the control unit 70 is set to start the compressor 21 and execute the determination mode. If the control unit 70 determines that the compressor 21 has been stopped for the predetermined time, the control unit 70 proceeds to step S2.

[0070] In step S2, the control unit 70 starts the compressor 21 to execute the determination mode.

[0071] In step S3, the control unit 70 starts the compressor 21 and then executes the determination mode.

[0072] -Judgment mode- Next, the determination mode executed by the control unit 70 will be described with reference to the flowchart of FIG.

[0073] <Step S11: Operate the utilization unit in cooling operation> First, the control unit 70 switches the four-way switching valve 22 of the heat source unit 2 to the state shown by the solid line in Figure 1 (cooling operation state), opens the expansion valve 35 of the heat source unit 2, and starts the compressor 21, the heat source fan 27, and the utilization fan 47.

[0074] The control unit 70 operates the usage fan 47 at a fan rotation speed that provides an airflow of medium or less among the selectable usage fan taps. For example, and not limited to, the fan tap L is used among the fan taps H, HM, M, LM, and L. However, the usage fan 47 may be, for example, the fan tap M or the fan tap LM among the selectable usage fan taps.

[0075] The indoor control unit 47 operates the utilization fan 47 at a rotation speed equal to or lower than the middle of the first rotation speed and the second rotation speed. The rotation speed of the utilization fan 47 is preferably set to 1 / 3 or less of the second rotation speed between the first rotation speed and the second rotation speed. Alternatively, the rotation speed of the utilization fan 47 may be set to the second rotation speed (minimum rotation speed) or may be set to a rotation speed lower than the second rotation speed.

[0076] <Step S12: Detection of degree of subcooling> Next, after performing operation for a predetermined time, the outdoor control unit 32 detects the degree of subcooling at the outlet of the heat source side heat exchanger 23.

[0077] In this embodiment, the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23 is detected by subtracting the refrigerant temperature value detected by the liquid side temperature sensor 31 from the refrigerant temperature value detected by the heat exchanger temperature sensor 30, or by converting the discharge pressure value of the compressor 21 detected by the discharge pressure sensor 29 to the saturation temperature value of the refrigerant and subtracting the refrigerant temperature value detected by the liquid side temperature sensor 31 from this saturation temperature value of the refrigerant.

[0078] <Step S13: Determining Whether or Not a Refrigerant Leaks> Next, the control unit 70 determines whether or not there is a refrigerant leak from the value of the degree of subcooling detected in step S12.

[0079] Specifically, if the subcooling degree value detected in step S12 is approximately the same as the target subcooling degree value (for example, the difference between the detected subcooling degree value and the target subcooling degree value is less than a predetermined value), the control unit 70 determines that there is no refrigerant leakage from the refrigerant circuit 10.

[0080] On the other hand, if the subcooling degree value detected in step S12 is smaller than the target subcooling degree value (for example, the difference between the detected subcooling degree value and the target subcooling degree value is a predetermined value or more), the control unit 70 determines that refrigerant is leaking from the refrigerant circuit 10.

[0081] (5) Refrigerant leak detection system Next, the refrigerant leakage determination system 100 will be described with reference to FIG.

[0082] The refrigerant leakage determination system 100 includes an air conditioner 1, a management device 61, and a remote monitoring server 63. The management device 61 is connected to a control unit 70 of the air conditioner 1 via a communication line. The management device 61 is provided, for example, in the same building as the air conditioner 1. The remote monitoring server 63 is connected to the management device 61 via a network 62 so as to be able to communicate with the management device 61.

[0083] The control unit 70 transmits various operational data of the air conditioner 1 to the management device 61. The management device 61 transmits predetermined information, including the result of the determination mode, from the information received from the control unit 70 to the remote monitoring server 63 via the network 62. Based on the information received from the management device 61, the remote monitoring server 63 notifies the manager of the air conditioner 1 as necessary.

[0084] The remote monitoring server 63 accumulates the determination result of the determination mode of the air conditioner 1. The control unit 70 of the air conditioner 1 immediately after the end of the determination mode or after a predetermined time has passed, transmits the determination result of the determination mode to the management device 61. The management device 61 periodically transmits predetermined information including the result of the determination mode to the remote monitoring server 63.

[0085] It should be noted that there is a possibility that a refrigerant leak and another abnormality that allows operation to continue may occur simultaneously in the air conditioner 1. In such a case, in order to prevent a situation in which the result of the determination mode cannot be notified to the remote monitoring server 63, it is preferable that the management device 61 increases the priority of the result of the determination mode and transmits it to the remote monitoring server 63.

[0086] Furthermore, it is preferable that the control unit 70 or management device 61 of the air conditioner 1 retains the results of the judgment mode for a certain period of time so that the operation results of the refrigerant leak detection are reliably transmitted to the remote monitoring server 63. The time for which the control unit 70 or management device 61 retains the results of the judgment mode may take into consideration the access interval between the remote monitoring server 63 and the management device 61.

[0087] (6) Features (6-1) The air conditioner 1 according to this embodiment has a heat source unit 2 and a utilization unit 4, and includes a refrigerant circuit 10, a discharge pressure sensor 29, a heat exchanger temperature sensor 30, a liquid-side temperature sensor 31, and a control unit 70. The refrigerant circuit 10 includes a compressor 21, a condenser, an expansion mechanism 35, and an evaporator, which are connected by refrigerant piping. The discharge pressure sensor 29, the heat exchanger temperature sensor 30, and the liquid-side temperature sensor 31 detect the temperature or pressure of the refrigerant in the refrigerant circuit 10. The control unit 70 starts the compressor 21 while the compressor 21 is not operating, and executes a determination mode in which the presence or absence of refrigerant leakage from the refrigerant circuit 10 is determined based on the detection values ​​of the discharge pressure sensor 29, the heat exchanger temperature sensor 30, and the liquid-side temperature sensor 31.

[0088] Conventional methods for determining the presence or absence of a refrigerant leak based on changes in refrigerant pressure or temperature while the system is stopped have the problem of poor accuracy. In contrast, the air conditioner 1 according to this embodiment starts the compressor 21 while it is stopped to determine the presence or absence of a refrigerant leak, enabling highly accurate determination of a refrigerant leak.

[0089] (6-2) In the air conditioner 1 according to this embodiment, the control unit 70 executes the determination mode when the compressor 21 has not been operated for a predetermined time.

[0090] In this air conditioner 1, when the compressor 21 has not been operated for a predetermined time, for example, even during seasons when the air conditioner 1 is used less frequently, it is possible to accurately determine whether or not there is a refrigerant leak.

[0091] (6-3) In the air conditioner 1 according to this embodiment, the utilization unit 4 has a utilization fan 47. The utilization fan 47 can be set to operate at a rotation speed range between a first rotation speed and a second rotation speed. When executing the determination mode, the control unit 70 operates the utilization fan 47 at a rotation speed equal to or lower than the middle of the first rotation speed and the second rotation speed.

[0092] In this air conditioner 1, when the utility fan 47 is operated to determine whether or not there is a refrigerant leak, even if the air blown out of the indoor unit 4 is not at a temperature appropriate for the people in the room, a decrease in comfort for the people in the room can be suppressed.

[0093] (6-4) The refrigerant leakage determination system 100 according to this embodiment includes an air conditioner 1 and a remote server 63. The air conditioner 1 is the air conditioner 1 according to this embodiment. The remote server 63 accumulates the determination result of the determination mode of the air conditioner 1. The control unit 70 transmits the determination result of the determination mode to the remote server 63.

[0094] In this refrigerant leakage determination system 100, the determination result of the determination mode of the air conditioner 1 can be transmitted to the remote server 63, thereby storing the determination result.

[0095] (7) Variations (7-1) Variation 1A In the above embodiment, the control unit 70 detects the degree of subcooling at the outlet of the heat source side heat exchanger 23 using the heat exchanger temperature sensor 30 or the discharge pressure sensor 29 and the liquid side temperature sensor 31 in the judgment mode, but this is not limited to this.

[0096] In the determination mode of the above embodiment, the control unit 70 operates the air conditioner 1 in cooling mode, but may also operate the air conditioner in heating mode. The control unit 70 may also perform a special operation to determine whether or not there is a refrigerant leak from the refrigerant circuit.

[0097] Further, an index other than the degree of subcooling may be used to detect refrigerant leakage.

[0098] For example, the suction pressure sensor 28 may be used to detect the suction pressure, and if the suction pressure is lower than a normal value, it may be determined that a refrigerant leak has occurred.

[0099] Also, the discharge pressure may be detected using the discharge pressure sensor 29, and if the discharge pressure is lower than a normal value, it may be determined that a refrigerant leak has occurred.

[0100] In addition, the gas side temperature sensor 44, the liquid side temperature sensor 43, and the suction pressure sensor 28 may be used to detect the suction superheat degree, and if the suction superheat degree is higher than a normal value, it may be determined that a refrigerant leak has occurred.

[0101] Also, the gas-side temperature sensor 44 may be used to detect the discharged gas refrigerant temperature, and if the discharged gas refrigerant temperature is higher than a normal value, it may be determined that a refrigerant leak has occurred.

[0102] In addition, the indoor temperature sensor 46 may be used to detect the temperature difference between the intake air temperature and the blown air temperature, and if the temperature difference between the intake air temperature and the blown air temperature is smaller than a normal value, it may be determined that a refrigerant leak has occurred.

[0103] In addition, a float valve (not shown) may be used to detect the liquid level in the receiver (not shown), and if the liquid level in the receiver is lower than the normal value, it may be determined that a refrigerant leak has occurred.

[0104] In addition, if the air conditioner has a water-cooled condenser, a cold water temperature sensor (not shown) can be used to detect the temperature difference between the cold water inlet temperature and the cold water outlet temperature, and if the temperature difference between the cold water inlet temperature and the cold water outlet temperature is smaller than a normal value, it can be determined that a refrigerant leak has occurred.

[0105] (7-2) Variation 1B When the compressor 21 is forced to operate while it is stopped to detect a refrigerant leak, the compressor 21 may be operated for a short time. Operation of the compressor 21 to detect a refrigerant leak while the compressor 21 is stopped is not desired by the user, and therefore it is preferable that the operation be completed in a short time. The short time is, for example, several tens of seconds.

[0106] In this case, the determination mode may be, for example, to determine the presence or absence of refrigerant leakage based on whether the temperature of the refrigerant changes in the heat source side heat exchanger 23 or the user side heat exchanger 42.

[0107] However, in a method of determining whether or not there is a refrigerant leak based on whether the refrigerant temperature changes in, for example, the heat source side heat exchanger 23 or the user side heat exchanger 42, the change in refrigerant temperature is observed in a short period of time and is therefore susceptible to the influence of outdoor and indoor temperatures. Therefore, the control unit of the air conditioner may determine whether or not there is a refrigerant leak from the refrigerant circuit based additionally on the ambient temperature around the heat source unit detected by an outdoor temperature sensor, or the ambient temperature around the user unit detected by an indoor temperature sensor.

[0108] A schematic refrigerant circuit diagram of an air conditioner 101 of modification 1B is shown in FIG. 4. In the air conditioner 101, the utilization unit 104 is provided with an indoor temperature sensor 46 that detects the indoor temperature. In addition, the heat source unit 102 is provided with an outdoor temperature sensor 33 that detects the outdoor temperature. The outdoor temperature sensor 33 is an example of a second detection unit in the claims that detects the ambient temperature around the heat source unit 102. In addition, the indoor temperature sensor 46 is an example of a second detection unit in the claims that detects the ambient temperature around the utilization unit 104. The configuration of the air conditioner 101 other than the indoor temperature sensor 46 and the outdoor temperature sensor 33 is the same as that of the air conditioner 1 described in this embodiment, so detailed description will be omitted.

[0109] In the air conditioner of modification 1B, refrigerant leakage can be determined relatively accurately based on the outdoor temperature or indoor temperature in addition to the temperature or pressure of the refrigerant flowing through the refrigerant circuit, even when the air conditioner 1 is operated for only a short time.

[0110] (7-3) Variation 1C When starting the compressor 21 to determine whether or not there is a refrigerant leak while the compressor 21 is not operating, the control unit 70 may execute the determination mode, further taking into consideration the presence or absence of people in the space to be air-conditioned by the air conditioner 1.

[0111] A schematic refrigerant circuit diagram of an air conditioner 111 of modification 1C is shown in Fig. 5. In the air conditioner 111, a utilization unit 114 is provided with a human detection sensor 48. The human detection sensor 48 detects the presence or absence of a person in the space to be air-conditioned by the air conditioner 111. When the human detection sensor 48 determines that no person is present in the space to be air-conditioned by the air conditioner 1, the control unit 70 of the air conditioner 1 executes a determination mode. The configuration of the air conditioner 111 other than the human detection sensor 48 is the same as that of the air conditioner 1 described in this embodiment, and therefore detailed description will be omitted.

[0112] However, regardless of the presence or absence of people in the space to be air-conditioned by the air conditioner 1, it is preferable to determine the presence or absence of a refrigerant leak once per predetermined period (for example, once per day).

[0113] In the air conditioner 1 of modification 1C, the air conditioner 1 is operated when no one is in the room, so it is possible to determine whether or not there is a refrigerant leak without affecting the comfort of the user.

[0114] (7-4) Variation 1D In the air conditioner 101 shown in Fig. 4, when the compressor 21 is started to determine the presence or absence of refrigerant leakage while the operation of the compressor 21 is stopped, the control unit 70 may execute the determination mode when the temperature of the first space to be air-conditioned by the air conditioner 101 is within a predetermined range. The predetermined range of the temperature of the first space to be air-conditioned is within the set temperature range of the air conditioner 101. The set temperature range of the air conditioner 101 is, for example, a range of 20°C to 25°C when the set temperature is 25°C during cooling operation, and a range of 20°C to 30°C when the set temperature is 20°C during heating operation.

[0115] Furthermore, when the control unit 70 executes the judgment mode and the temperature of the first space falls outside a predetermined range, the control unit 70 may end the judgment mode.

[0116] Furthermore, the control unit 70 may end the judgment mode when the temperature of the first space rises or falls by a predetermined temperature even if the temperature is within a predetermined range by executing the judgment mode. For example, when operating in a cooling operation state in the judgment mode, the judgment mode ends when the temperature of the first space that is the target of air conditioning by the air conditioner 101 rises by, for example, 3 degrees from the start of the judgment mode. Also, when operating in a heating operation state in the judgment mode, the judgment mode ends when the temperature of the first space that is the target of air conditioning by the air conditioner 101 falls by, for example, 3 degrees from the start of the judgment mode.

[0117] However, even if the temperature of the first space falls outside the specified range or rises or falls by more than the specified temperature by executing the judgment mode, it is preferable to judge whether or not there is a refrigerant leak once per specified period (for example, once per day).

[0118] The air conditioner 101 of the modification 1D has the same configuration as the air conditioner 101 described in the modification 1B.

[0119] In the air conditioner 101 of modification 1D, by executing the determination mode when the state is comfortable, it is possible to determine the presence or absence of a refrigerant leak while minimizing the impact on the user's comfort.

[0120] (7-5) Variation 1E In the air conditioner 101 shown in Fig. 4, when the compressor 21 is started to determine the presence or absence of refrigerant leakage while the operation of the compressor 21 is stopped, the control unit 70 may execute the determination mode when the thermal index of the first space that is the target of air conditioning by the air conditioner 101 is within a predetermined range. For example, the control unit 70 may execute the determination mode when the discomfort index of the first space that is the target of air conditioning by the air conditioner 101 is 65 or more during heating operation, or 75 or less during cooling operation. The discomfort index is calculated by the formula "0.81 x room temperature + 0.01 x humidity x (0.99 x room temperature - 14.3) + 46.3".

[0121] Furthermore, when the thermal index of the first space falls outside a predetermined range as a result of executing the judgment mode, the control unit 70 may end the judgment mode.

[0122] Furthermore, the control unit 70 may end the judgment mode when the thermal index of the first space rises or falls by a predetermined temperature even if it is within a predetermined range by executing the judgment mode.

[0123] However, even if the thermal index of the first space falls outside the specified range or rises or falls by more than a specified temperature by executing the judgment mode, it is preferable to judge whether or not there is a refrigerant leak once per specified period (for example, once per day).

[0124] The air conditioner 101 of the modification 1E has the same configuration as the air conditioner 101 described in the modification 1B.

[0125] In the air conditioner 101 of modification 1E, by executing the determination mode when the state is comfortable, it is possible to determine the presence or absence of a refrigerant leak while minimizing the impact on the user's comfort.

[0126] (7-6) Variation 1F The control unit 70 may perform cooling operation to use the utilization side heat exchanger 42 as an evaporator, execute the judgment mode, and then stop the compressor 21 and execute a drying operation to dry the utilization side heat exchanger 42 with the utilization fan 47.

[0127] In the air conditioner of variant 1F, even if the user side heat exchanger (evaporator) 42 becomes wet due to cooling operation while the air conditioner 1 is stopped, the evaporator 42 can be dried by performing drying operation after the judgment mode ends.

[0128] Furthermore, the control unit 70 may perform a heating operation, use the heat-source-side heat exchanger 23 as an evaporator, and after executing the determination mode, stop the compressor 21 and execute a drying operation to dry the heat-source-side heat exchanger 23 with the heat-source fan 27. Even if the heat-source-side heat exchanger (evaporator) 23 becomes wet by performing a heating operation while the air conditioner 1 is stopped, the heat-source-side heat exchanger 23 can be dried using the heat-source fan 27 after executing the determination mode.

[0129] (7-7) Variation 1G When the compressor 21 is started to determine the presence or absence of refrigerant leakage while the compressor 21 is stopped, the control unit 70 may execute the determination mode simultaneously with a cleaning operation for cleaning the air conditioner 1. In the cleaning operation for cleaning the air conditioner 1, a heating operation is performed after a cooling operation. By drying the inside of the indoor unit 4, the growth of mold can be suppressed.

[0130] In the air conditioner of modification 1G, the determination mode can be executed simultaneously with the cleaning operation while the compressor is stopped.

[0131] (7-8) Variation 1H When starting the compressor 21 to determine the presence or absence of a refrigerant leak while the compressor 21 is stopped, the control unit 70 may execute the determination mode in the operating state of the air conditioner 1 that was set before the compressor 21 was stopped. For example, when the operating mode that was set before the compressor 21 was stopped was the heating operation, the control unit 70 may determine the presence or absence of a refrigerant leak during the heating operation.

[0132] In the air conditioner of modification 1H, in the determination mode, the air conditioner is operated in the set operating state of the air conditioner, so that the determination mode can be executed while minimizing the impact on the comfort of the user.

[0133] (7-9) Variation 1I 4, when the compressor 21 is started to determine the presence or absence of a refrigerant leak while the compressor 21 is stopped, the control unit 70 may switch the operation state of the air conditioner 1 based on the outdoor temperature or the indoor temperature. When the control unit 70 starts the compressor 21 while the compressor 21 is stopped, the control unit 70 may execute the determination mode in the operation state of the air conditioner 101 that was set before the compressor 21 was stopped, but if the outdoor temperature or the indoor temperature is outside the allowable range of the set operation state, the pressure in the refrigerant circuit 10 may increase, and the compressor 21 may be subjected to a load.

[0134] Therefore, when the operating state set in the air conditioner 101 is a heating operating state and the outdoor temperature or the indoor temperature is not within the range of the set temperature (operable temperature) of the operating state, the control unit 70 may switch the state of the refrigerant circuit 10 to a cooling operating state and execute the judgment mode.

[0135] In the air conditioner of variant example 1I, even if the operating state set in the air conditioner is a heating operation state, if the outdoor temperature or the indoor temperature is not within the range of the set temperature for the heating operation state, the operation state is switched to cooling operation and the judgment mode is executed, thereby reducing the load on the compressor 21.

[0136] The air conditioner 101 of Modification 1I has the same configuration as the air conditioner 101 described in Modification 1B.

[0137] (7-10) Variation 1J In this embodiment, an air conditioner capable of switching between heating and cooling has been described, but the present invention is not limited to this. An air conditioner exclusively for cooling may also be used. The refrigeration cycle device may be a refrigeration cycle device other than an air conditioner, such as a refrigeration / freezing unit, a heat pump water heater, or a water chilling unit.

[0138] (7-11) Variation 1K In this embodiment, the control unit 70 of the air conditioner 1 determines whether or not there is a refrigerant leak, but the presence or absence of a refrigerant leak may also be determined in the management device 61 or remote monitoring server 63 of the refrigerant leak determination system 100. When the control unit 70 starts the compressor 21 to determine whether or not there is a refrigerant leak while the compressor 21 is stopped, the control unit 70 acquires various operating data of the air conditioner 1 and transmits it to the management device 61 or remote monitoring server 63. The management device 61 or remote monitoring server 63 determines whether or not there is a refrigerant leak based on the acquired various operating data of the air conditioner 1. Note that the refrigerant leak determination system 100 may be configured not to include the management device 61. In this case, the control unit 70 of the air conditioner 1 may directly transmit various data to the remote monitoring server 63, and the remote monitoring server 63 may determine whether or not there is a refrigerant leak.

[0139] (7-12) Variation 1L Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. [Explanation of symbols]

[0140] 1, 101, 111 Air conditioner (refrigeration cycle device) 2, 102 Heat source unit 4, 104, 114 Usage Units 6 Liquid refrigerant connection piping 7 Gas refrigerant connection piping 10 Refrigerant circuit 21 Compressor 21a Motor 22 Four-way switching valve (switching mechanism) 23 Heat source side heat exchanger 24 Accumulator 27 Heat source fan 27a Fan motor 28 Intake pressure sensor (first detection part) 29 Discharge pressure sensor (first detection part) 30 Heat exchanger temperature sensor (first detection section) 31 Liquid side temperature sensor (first detection section) 32 Heat source side control unit (control unit) 33 Outdoor temperature sensor (second detection unit) 35 Expansion valve (expansion mechanism) 42 User side heat exchanger 43 Liquid side temperature sensor (first detection section) 44 Gas side temperature sensor (first detection part) 45 User side control unit (control unit) 46 Indoor temperature sensor (second detection unit) 47 Fans in use 47a Fan motor 48 Human detection sensor 63 Remote Server (Server) 70 Control section 100 Remote management system (refrigerant leak detection system) [Prior art documents] [Patent documents]

[0141] [Patent Document 1] Patent No. 6257801

Claims

1. A refrigeration cycle apparatus having a heat source unit (2, 102) and a utilization unit (4, 104, 114), a refrigerant circuit (10) in which a compressor (21), a condenser, an expansion mechanism (35), and an evaporator are connected by refrigerant piping; a first detection unit (28, 29, 30, 31, 43, 44) that detects a temperature or a pressure of a refrigerant in the refrigerant circuit; a control unit (70) that executes a determination mode in which, when it is determined that the compressor has been stopped for a predetermined time, the control unit starts the compressor and determines whether or not there is a refrigerant leak from the refrigerant circuit during operation of the compressor based on a detection value of the first detection unit; Equipped with The refrigeration cycle device is an air conditioner, The refrigeration cycle device is capable of switching an operating state between a cooling operation and a heating operation, The control unit executes the determination mode in an operating state of the refrigeration cycle device that is set before the compressor is stopped. Refrigeration cycle device (1, 101, 111).

2. The control unit operates the compressor for a short period of time when executing the determination mode. The refrigeration cycle device according to claim 1.

3. The utilization unit has a utilization fan (47), The utilization fan can be set to operate in a rotation speed range between a first rotation speed and a second rotation speed, When executing the determination mode, the control unit operates the utilization fan at a rotation speed that is equal to or lower than an intermediate speed between the first rotation speed and the second rotation speed. The refrigeration cycle device according to claim 2.

4. A second detection unit (33, 46) that detects the ambient temperature around the heat source unit or the ambient temperature around the utilization unit; Further equipped with The control unit determines whether or not a refrigerant leaks from the refrigerant circuit based on an ambient temperature around the heat source unit or an ambient temperature around the utilization unit. The refrigeration cycle device according to any one of claims 1 to 3.

5. a human detection sensor (48) installed in a first space that is an air-conditioning target of the refrigeration cycle device and configured to detect the presence or absence of a human in the first space; Further equipped with The control unit executes the determination mode when the human detection sensor determines that no human is present in the first space. The refrigeration cycle device according to any one of claims 1 to 4.

6. The control unit executes the determination mode when a temperature or a thermal index of a first space that is an air-conditioning target of the refrigeration cycle device is within a predetermined range. The refrigeration cycle device according to any one of claims 1 to 5.

7. The utilization unit has a heat exchanger (42) and a utilization fan, The control unit uses the heat exchanger as an evaporator, and then stops the compressor after executing the determination mode. A drying operation is performed to dry the heat exchanger by using the utilization fan. The refrigeration cycle device according to claim 1.

8. The control unit executes the determination mode simultaneously with a cleaning operation for cleaning the refrigeration cycle device. The refrigeration cycle device according to any one of claims 1 to 7.

9. The control unit executes the determination mode once a day. The refrigeration cycle device according to any one of claims 1 to 8.

10. A refrigeration cycle device according to any one of claims 1 to 9, A server (63) that accumulates a determination result of a determination mode of the refrigeration cycle device; Equipped with The control unit transmits a determination result of the determination mode to the server. A refrigerant leak detection system (100).

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