JP7534664B2 - Refrigerant leakage detection method and refrigeration cycle device - Google Patents

Description

Related to a refrigerant leakage detection method and a refrigeration cycle device.

Patent Document 1 (WO 2015/004747) discloses a refrigeration cycle device that includes a refrigerant circuit in which a refrigerant is circulated through a compressor, a condenser, an expansion valve, and an evaporator, the compressor and the condenser are connected by a first extension pipe, and the expansion valve and the evaporator are connected by a second extension pipe, a detection unit that detects an operating state quantity of the refrigerant circuit, and a control unit that performs a refrigerant leak detection operation that calculates the amount of refrigerant inside the refrigerant circuit based on the operating state quantity detected by the detection unit and detects a refrigerant leak by comparing the calculated refrigerant amount with a reference refrigerant amount, and the control unit controls the dryness of the refrigerant at the outlet of the second extension pipe to 0.1 or more and 0.7 or less during the refrigerant leak detection operation.

However, in the refrigeration cycle device of Patent Document 1, the dryness of the refrigerant at the outlet of the second extension pipe must be controlled to 0.1 or more and 0.7 or less during refrigerant leak detection operation.

The refrigerant leakage determination method of the first aspect includes the following steps: A refrigerant circuit formed by connecting a heat source unit and a utilization unit with a communication pipe is filled with a first charge amount of refrigerant that is less than a target charge amount. Then, a first trial operation is performed to circulate the first charge amount of refrigerant in the refrigerant circuit, and first trial operation data is obtained. Then, after the acquisition step, refrigerant is filled into the refrigerant circuit until the target charge amount is reached. Then, normal operation data is obtained during normal operation after the refrigerant circuit has been filled with the target charge amount. Then, based on the normal operation data and the first trial operation data, it is determined whether or not refrigerant is leaking from the refrigerant circuit.

According to the first aspect of the refrigerant leakage determination method, a first test operation is performed in which a first charge amount of refrigerant, which is less than the target charge amount, is circulated, and first test operation data is obtained. This first test operation data is data that indicates the behavior when refrigerant leaks. Therefore, by comparing the normal operation data obtained during normal operation after the target charge amount is filled with the first test operation data, it is possible to determine whether or not refrigerant is leaking from the refrigerant circuit.

The refrigerant leakage determination method of the second aspect is the refrigerant leakage determination method of the first aspect, further comprising the following steps: Fill the refrigerant circuit with a second charge amount of refrigerant that is greater than the first charge amount and less than the target charge amount. Perform a second test operation in which the second charge amount of refrigerant is circulated in the refrigerant circuit, and obtain second test operation data. In the determination step, the presence or absence of refrigerant leakage from the refrigerant circuit is determined based on the normal operation data, the first test operation data, and the second test operation data.

In the second aspect of the refrigerant leakage determination method, a second test operation is performed in which a second charge amount of refrigerant between the first charge amount and the target charge amount is circulated, and second test operation data is obtained. This second test operation data indicates the behavior when the refrigerant leaks, and is different from the first test operation data. Therefore, by comparing the normal operation data obtained during normal operation after the target charge amount is filled with the first test operation data and the second test operation data, the accuracy of determining whether or not there is a refrigerant leakage can be improved.

The refrigeration cycle apparatus of the third aspect is a refrigeration cycle apparatus including a heat source unit, a utilization unit, and a communication pipe connecting the heat source unit and the utilization unit. The refrigeration cycle apparatus includes a refrigerant circuit and a control unit. The refrigerant circuit is formed by connecting the heat source unit and the utilization unit with the communication pipe. The control unit controls the operation of the refrigerant circuit. The control unit performs a first test operation in which a first charge amount of refrigerant that is less than a target charge amount is circulated in the refrigerant circuit, and acquires first test operation data.

According to the third aspect of the refrigeration cycle device, the control unit performs a first test operation in which a first charge amount of refrigerant, which is less than the target charge amount, is circulated, and acquires first test operation data. This first test operation data is data that indicates the behavior when refrigerant leaks. Therefore, by comparing the normal operation data acquired during normal operation after the target charge amount is filled with the first test operation data, it is possible to determine whether or not refrigerant is leaking from the refrigerant circuit.

The refrigeration cycle device of the fourth aspect is the refrigeration cycle device of the third aspect, in which the control unit performs a second test operation in which a second charge amount of refrigerant, which is greater than the first charge amount and less than the target charge amount, is circulated in the refrigerant circuit, and acquires second test operation data.

In the refrigeration cycle device of the fourth aspect, the control unit performs a second test operation in which a second charge amount of refrigerant between the first charge amount and the target charge amount is circulated, and acquires second test operation data. This second test operation data indicates the behavior when refrigerant leaks, and is different from the first test operation data. Therefore, by comparing the normal operation data acquired during normal operation after the target charge amount is filled with the first test operation data and the second test operation data, the accuracy of determining whether or not refrigerant is leaking can be improved.

FIG. 1 is a diagram illustrating a configuration of a management system according to an embodiment of the present disclosure. 1 is a diagram showing a functional block configuration of a refrigeration cycle device according to an embodiment of the present disclosure. 1 is a schematic configuration diagram of a refrigeration cycle device according to an embodiment. 3 is a flowchart showing a refrigerant leakage determination method according to the embodiment. 10 is a flowchart showing a refrigerant leakage determination method according to a modified example.

(1) Overall Configuration of the Management System for the Refrigeration Cycle Apparatus As shown in Fig. 1, the management system 100 for the refrigeration cycle apparatus 1 is a device for managing the refrigeration cycle apparatus 1. The management system 100 for the refrigeration cycle apparatus 1 is a system for determining the presence or absence of a refrigerant leak in the refrigeration cycle apparatus 1, and notifying a user when it is determined that a refrigerant leak exists. Note that the user includes a person who uses the refrigeration cycle apparatus 1 and a person who manages the refrigeration cycle apparatus 1.

The management system 100 includes a refrigeration cycle device 1, a server 40, and an information device 50. The server 40 is connected to the refrigeration cycle device 1. The information device 50 is connected to the server 40. Each component included in the management system 100 will be described below.

(2) Refrigeration cycle device The refrigeration cycle device 1 is a device that processes a heat load in a target space by performing a vapor compression refrigeration cycle, and is, for example, an air conditioner that conditions the air in the target space. As shown in Fig. 2 and Fig. 3, the refrigeration cycle device 1 has one heat source unit 20, multiple utilization units 30, communication pipes 5 and 6 that connect the heat source unit 20 and the multiple utilization units 30, and a remote control 36. In this embodiment, the heat source unit 20 and the utilization units 30 are connected to each other so as to be able to communicate with each other via a transmission line 97 shown in Fig. 2.

The vapor compression refrigerant circuit 10 of the refrigeration cycle device 1 is configured by connecting the heat source unit 20 and the utilization unit 30 via the connecting pipes 5 and 6. The refrigerant circuit 10 is filled with a refrigerant for performing a vapor compression refrigeration cycle. The refrigerant filled in the refrigerant circuit 10 is not particularly limited, and may be, for example, R32. The refrigerant circuit 10 is filled with refrigerating machine oil together with the above-mentioned refrigerant.

3, the heat source unit 20 is connected to the utilization unit 30 via the connection pipes 5 and 6, and constitutes a part of the refrigerant circuit 10. The heat source unit 20 mainly includes a compressor 21, a four-way switching valve 22, a first heat exchanger 23, a first expansion valve 24, a first fan 25, a receiver 26, a gas side shutoff valve 28, a liquid side shutoff valve 29, and the first refrigerant pipe 11 to the seventh refrigerant pipe 17.

The compressor 21 is a device that compresses low-pressure refrigerant in the refrigeration cycle to high pressure. Here, a compressor with a sealed structure in which a volumetric compression element such as a rotary type or scroll type is rotated and driven by a compressor motor can be used as the compressor 21. The compressor motor is used to change the capacity, and the operating frequency can be controlled by an inverter. The seventh refrigerant pipe 17, which is a suction pipe, is connected to the suction side of the compressor 21. The first refrigerant pipe 11, which is a discharge pipe, is connected to the discharge side of the compressor 21.

The four-way switching valve 22 is a valve whose flow path is switched by controlling the movement of a valve body (not shown), and is a valve that switches the refrigerant circuit 10 between a cooling connection state and a heating connection state. Specifically, in the cooling connection state, the four-way switching valve 22 is switched to a state in which it connects the first refrigerant pipe 11 connected to the discharge side of the compressor 21 and the second refrigerant pipe 12 connected to the first heat exchanger 23, while connecting the seventh refrigerant pipe 17 connected to the suction side of the compressor 21, the receiver 26, the sixth refrigerant pipe 16, and the fifth refrigerant pipe 15 connected to the gas side shutoff valve 28. In addition, in the heating connection state, the four-way switching valve 22 is switched to a state in which it connects the first refrigerant pipe 11 connected to the discharge side of the compressor 21 and the fifth refrigerant pipe 15 connected to the gas side shutoff valve 28, while connecting the seventh refrigerant pipe 17 connected to the suction side of the compressor 21, the receiver 26, the sixth refrigerant pipe 16, and the second refrigerant pipe 12 connected to the first heat exchanger 23.

The first heat exchanger 23 is a heat exchanger that functions as a condenser for high-pressure refrigerant in the refrigeration cycle during cooling operation, and as an evaporator for low-pressure refrigerant in the refrigeration cycle during heating operation. The gas side end of the first heat exchanger 23 is connected to the four-way switching valve 22 via the second refrigerant piping 12. The liquid side end of the first heat exchanger 23 is connected to the first expansion valve 24 via the third refrigerant piping 13.

The first expansion valve 24 is provided between the liquid side outlet of the first heat exchanger 23 in the refrigerant circuit 10 and the liquid side shutoff valve 29. The first expansion valve 24 is an electric expansion valve whose valve opening can be adjusted by controlling the movement of a valve body (not shown) relative to a valve seat (not shown). The first expansion valve 24 and the liquid side shutoff valve 29 are connected via the fourth refrigerant pipe 14.

The first fan 25 draws outdoor air into the heat source unit 20, exchanges heat with the refrigerant in the first heat exchanger 23, and then generates an air flow to be discharged to the outside. The first fan 25 is driven to rotate by a fan motor.

The receiver 26 is provided between the suction side of the compressor 21 and one of the connection ports of the four-way switching valve 22, and is a refrigerant container capable of storing excess refrigerant in the refrigerant circuit 10 as liquid refrigerant. The inlet side of the receiver 26 is connected to the four-way switching valve 22 via the sixth refrigerant pipe 16. The outlet side of the receiver 26 is connected to the suction side of the compressor 21 via the seventh refrigerant pipe 17.

The liquid side shutoff valve 29 is a manual valve arranged at the connection between the heat source unit 20 and the liquid side connecting pipe 6. The gas side shutoff valve 28 is a manual valve arranged at the connection between the heat source unit 20 and the gas side connecting pipe 5.

The heat source unit 20 is provided with a discharge pressure sensor 61, a discharge temperature sensor 62, a suction pressure sensor 63, a suction temperature sensor 64, a liquid side temperature sensor 65, an outside air temperature sensor 66, and the like. The discharge pressure sensor 61 detects the pressure of the refrigerant flowing through the first refrigerant pipe 11, which is a discharge pipe connecting the discharge side of the compressor 21 and one of the connection ports of the four-way switching valve 22. The discharge temperature sensor 62 detects the temperature of the refrigerant flowing through the first refrigerant pipe 11, which is a discharge pipe. The suction pressure sensor 63 detects the pressure of the refrigerant flowing through the seventh refrigerant pipe 17, which is a suction pipe connecting the suction side of the compressor 21 and the receiver 26. The suction temperature sensor 64 detects the temperature of the refrigerant flowing through the seventh refrigerant pipe 17, which is a suction pipe. The liquid side temperature sensor 65 detects the temperature of the refrigerant flowing through the liquid side outlet of the first heat exchanger 23, which is the opposite side to the side to which the four-way switching valve 22 is connected. The outside air temperature sensor 66 detects the outdoor air temperature before passing through the first heat exchanger 23. Each of these sensors is electrically connected to the first control unit 20c, which will be described later, and transmits a detection signal to the first control unit 20c.

As shown in FIG. 2, the heat source unit 20 has a first communication unit 20a, a first input unit 20b, a first control unit 20c, and a first memory unit 20d.

The first communication unit 20a is an interface for communicating with the utilization unit 30. The first communication unit 20a is also an interface for communicating with the server 40.

The first input unit 20b is a button that accepts an instruction to perform a first test run from an operator. Here, the first input unit 20b has a button that accepts an instruction to perform a first test run and a button that accepts an instruction to perform a final test run. When the first input unit 20b accepts an instruction to perform the first test run or the final test run, the first control unit 20c executes the first test run or the final test run, and multiple test run data described below are detected.

The first control unit 20c is an arithmetic processing device such as a CPU (Central Processing Unit). The first control unit 20c reads and executes the program stored in the first storage unit 20d.

The first control unit 20c controls the operation of each part constituting the heat source unit 20. The first control unit 20c is capable of communicating control signals via a transmission line 97 between the second control unit 35 of each utilization unit 30. Here, the first control unit 20c connected to the transmission line 97 and each second control unit 35 cooperate to control the operation of the entire refrigeration cycle device 1. In other words, the first control unit 20c cooperates with the second control unit 35 to control the operation of the refrigerant circuit 10.

Specifically, the first control unit 20c operates each component of the heat source unit 20 according to control commands such as start, stop, set temperature, set humidity, set air volume or set air direction, and operation mode of the utilization unit 30. More specifically, the first control unit 20c generates control commands for adjusting the frequency of the compressor 21, the rotation speed of the first fan 25, the opening degree of the first expansion valve 24, and the like.

Furthermore, the first control unit 20c performs a first test operation in which a first charge amount of refrigerant that is less than the target charge amount (100%) is circulated in the refrigerant circuit 10, and acquires first test operation data. The target charge amount is the required refrigerant charge amount described in the installation manual. The target charge amount is also the amount of refrigerant circulating in the refrigerant circuit 10 during normal operation such as cooling operation or heating operation. The first charge amount is, for example, 50% or more but less than 100% of the target charge amount, and in this embodiment, it is 70% of the target charge amount.

Specifically, when the first input unit 20b receives a command to perform the first test run, the first control unit 20c operates each part of the heat source unit 20 to perform the first test run, and sends a command to the second control unit 35 of the utilization unit 30 to operate each part of the utilization unit 30. Then, the first control unit 20c acquires first test run data during the first test run. The first test run data is, for example, the opening degree of the second expansion valve 33 of each utilization unit 30. Then, the first control unit 20c stores the acquired first test run data in the first storage unit 20d.

The first control unit 20c also performs a final test run in which the target charge amount of refrigerant is circulated in the refrigerant circuit 10, and acquires final test run data. Specifically, when the first input unit 20b receives a command to perform the final test run, the first control unit 20c operates each part constituting the heat source unit 20 to perform the final test run, and sends a command to the second control unit 35 of the utilization unit 30 to operate each part constituting the utilization unit 30. The first control unit 20c then acquires final test run data during the final test run. The final test run data is, for example, the opening degree of the second expansion valve 33 of each utilization unit 30. The acquired final test run data is then stored in the first storage unit 20d.

In this way, the first control unit 20c has multiple trial operation modes. In this embodiment, the first control unit 20c has two modes: a first trial operation in which a first charge amount of refrigerant that is less than the target charge amount is circulated, and a final trial operation in which the target charge amount of refrigerant is circulated.

Furthermore, the first control unit 20c acquires normal operation data during normal operation after the target filling amount is filled into the refrigerant circuit 10, and determines whether or not refrigerant is leaking from the refrigerant circuit 10 based on the normal operation data and the first trial operation data. In this embodiment, the first control unit 20c determines whether or not refrigerant is leaking from the refrigerant circuit 10 based on the normal operation data, the first trial operation data, and the final trial operation data. Here, the first control unit 20c compares the normal operation data when conditions similar to those of the first trial operation are satisfied during normal operation with the first trial operation data, and determines that refrigerant has leaked from the refrigerant circuit 10 when the state is similar to the first trial operation data.

The first test operation data and the final test operation data acquired by the first control unit 20c are, for example, data on the opening degree of each second expansion valve 33 when all of the multiple utilization units 30 are in cooling operation. The first control unit 20c acquires the opening degree of each second expansion valve 33 as normal operation data when all of the utilization units 30 are in cooling operation during normal operation. Then, the first control unit 20c compares the opening degree of each second expansion valve 33 as the first test operation data, the opening degree of each second expansion valve 33 as the final test operation data, and the opening degree of each second expansion valve 33 as the normal operation data. Specifically, the presence or absence of refrigerant leakage is determined by calculating how close the opening degree of each second expansion valve 33 during normal operation is to the opening degree of each second expansion valve 33 during the first test operation from the opening degree of each second expansion valve 33 during the final test operation. Note that the target evaporation temperature is the same in the first test operation, the final test operation, and the normal operation.

The first memory unit 20d has a ROM, a RAM, a hard disk, etc. The first memory unit 20d stores a program that can be read and executed by the first control unit 20c. The first memory unit 20d also stores first test run data, final test run data, normal operation data, etc.

(2-2) Usage Unit The usage unit 30 is installed, for example, on a wall or ceiling of a room which is a target space. The usage unit 30 is connected to the heat source unit 20 via communication pipes 5 and 6, and constitutes a part of the refrigerant circuit 10. In the refrigeration cycle device 1 of this embodiment, a plurality of usage units 30 are connected in parallel to one heat source unit 20. Since each usage unit 30 has the same configuration, one usage unit 30 will be described below.

The utilization unit 30 has a second heat exchanger 31, an eighth refrigerant pipe 18, a ninth refrigerant pipe 19, a second fan 32, and a second expansion valve 33.

The liquid side of the second heat exchanger 31 is connected to the liquid side connecting pipe 6 via the eighth refrigerant pipe 18, and the gas side end is connected to the gas side connecting pipe 5 via the ninth refrigerant pipe 19. The second heat exchanger 31 is a heat exchanger that functions as an evaporator for low-pressure refrigerant in the refrigeration cycle during cooling operation, and as a condenser for high-pressure refrigerant in the refrigeration cycle during heating operation.

The second fan 32 draws indoor air into the utilization unit 30, exchanges heat with the refrigerant in the second heat exchanger 31, and then generates an air flow to be discharged to the outside. The second fan 32 is driven to rotate by a fan motor. The second fan 32 can be driven at a set air volume received from the remote control 36.

The second expansion valve 33 is provided in the refrigerant circuit 10 between the liquid side inlet of the second heat exchanger 31 and the liquid side connection pipe 6. The second expansion valve 33 is an electric expansion valve whose valve opening can be adjusted by controlling the movement of a valve body (not shown) relative to a valve seat (not shown). The second expansion valve 33 is provided corresponding to the liquid side of the second heat exchanger 31. The second expansion valve 33 is an expansion mechanism that adjusts the flow rate of the refrigerant flowing through the second heat exchanger 31 while reducing the pressure of the refrigerant.

The utilization unit 30 is provided with a liquid side heat exchanger temperature sensor 71, an air temperature sensor 72, etc. The liquid side heat exchanger temperature sensor 71 detects the temperature of the refrigerant flowing through the liquid refrigerant side inlet of the second heat exchanger 31. The air temperature sensor 72 detects the indoor air temperature before passing through the second heat exchanger 31. Each of these sensors is electrically connected to the second control unit 35 described below, and transmits a detection signal to the second control unit 35.

The utilization unit 30 has a second communication unit 34 and a second control unit 35. The second communication unit 34 is an interface for communicating with the heat source unit 20.

The second control unit 35 has a microcomputer including a processor such as a CPU (Central Processing Unit) and memory.

The second control unit 35 has a second control unit 35 and a second communication unit 34 that control the operation of each part that constitutes the utilization unit 30. The second control unit 35 receives a control signal from the heat source unit 20 via the second communication unit 34, and operates each part that constitutes the utilization unit 30 based on the control signal. Specifically, the second control unit 35 generates control commands to adjust the rotation speed of the second fan 32, the opening degree of the second expansion valve 33, etc.

The second control unit 35 also sends data related to the operating state, such as the ON/OFF state and the intake temperature, to the heat source unit 20 via the second communication unit 34.

A remote control 36 that accepts operation inputs for each utilization unit 30 is separately attached to each utilization unit 30. The remote control 36 has an input section that accepts control commands for each utilization unit 30, and a display section that displays the operating status of each utilization unit 30. The operating status displayed on the display section of the remote control 36 includes information indicating the operating state, such as cooling operation, heating operation, inspection, etc., as well as information on the set temperature, air volume, wind direction, etc.

(3) Server The server 40 shown in Fig. 1 is connected to the refrigeration cycle apparatus 1 via a communication line, whether wired or wireless. The server 40 has a function of monitoring and controlling the refrigeration cycle apparatus 1. The server 40 in this embodiment is built on a cloud.

When the first control unit 20c determines that there is a refrigerant leak, the server 40 receives notification of this from the first control unit 20c and notifies the user. Here, when the server 40 determines that there is a refrigerant leak, it notifies the user's information device 50. The notification is performed by issuing a warning to the user using sound, light, display, etc.

(4) Information Device The information device 50 is a device that is notified when it is determined that there is a refrigerant leak in the refrigeration cycle apparatus 1. The type of the information device 50 is not particularly limited, and may be, for example, a smartphone, a wearable device, a personal computer, a tablet, etc. Examples of wearable devices include wristband-type, wristwatch-type, and other arm-worn devices, headband-type or eyeglass-type devices, and body-worn devices such as clothing-type devices.

(5) Normal Operation The refrigeration cycle apparatus 1 can perform at least a cooling operation and a heating operation mode as a normal operation. Note that, in the refrigeration cycle apparatus 1 of the present embodiment, the multiple utilization units 30 can individually perform a cooling operation or a heating operation.

Based on instructions received from the remote control 36 or the like, the first control unit 20c and the second control unit 35 of the refrigeration cycle device 1 determine whether the operation mode is cooling or heating, and execute the determined operation mode.

(5-1) Cooling operation The cooling operation is performed by the first control unit 20c and the second control unit 35, which have received a command for cooling operation via the remote control 36, controlling the operation of the compressor 21, the four-way switching valve 22, the first expansion valve 24, the first fan 25, the second fan 32, the second expansion valve 33, etc., which are components of the heat source unit 20 and the utilization unit 30.

During cooling operation, the four-way switching valve 22 is switched so that the first heat exchanger 23 functions as a refrigerant condenser and the second heat exchanger 31 functions as a refrigerant evaporator (the state shown by the solid line of the four-way switching valve 22 in Figure 1).

In the refrigerant circuit 10 in this state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21, compressed to the high pressure in the refrigeration cycle, and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the first heat exchanger 23 through the four-way switching valve 22. The high-pressure refrigerant sent to the first heat exchanger 23 exchanges heat with the outdoor air supplied by the first fan 25 in the first heat exchanger 23 and condenses. The high-pressure refrigerant condensed in the first heat exchanger 23 is sent to the first expansion valve 24 and reduced in pressure to the low pressure in the refrigeration cycle. The low-pressure refrigerant reduced in pressure in the first expansion valve 24 flows out of the heat source unit 20 and is branched and sent to each utilization unit 30 through the liquid side communication pipe 6. The refrigerant sent to the utilization unit 30 is reduced in pressure to the low pressure in the refrigeration cycle by the second expansion valve 33 and sent to the second heat exchanger 31. The low-pressure refrigerant sent to the second heat exchanger 31 evaporates in the second heat exchanger 31 by heat exchange with the indoor air supplied by the second fan 32. As a result, the indoor air is cooled and blown out into the room. The low-pressure refrigerant evaporated in the second heat exchanger 31 is sucked back into the compressor 21 through the gas side connecting pipe 5, the four-way switching valve 22, and the receiver 26. In this way, in the cooling operation, the first control unit 20c and the second control unit 35 operate to circulate the refrigerant sealed in the refrigerant circuit 10 through the compressor 21, the first heat exchanger 23, the first expansion valve 24, the second expansion valve 33, and the second heat exchanger 31 in that order.

During cooling operation, the first control unit 20c and the second control unit 35 perform capacity control to control the capacity of the compressor 21 so that the evaporation temperature of the refrigerant in the refrigerant circuit 10 approaches a predetermined target evaporation temperature. The capacity control of the compressor 21 is performed by controlling the rotation speed (frequency) of the compressor motor. The evaporation temperature of the refrigerant is obtained by converting the suction pressure detected by the suction pressure sensor 63 into the saturation temperature of the refrigerant. The evaporation temperature of the refrigerant means a temperature obtained by converting the pressure (evaporation pressure of the refrigerant in the refrigerant circuit 10) representative of the low-pressure refrigerant in the refrigeration cycle that flows from the outlet of the second expansion valve 33 to the suction side of the compressor 21 via the second heat exchanger 31 into the saturation temperature of the refrigerant, or the saturation temperature of the refrigerant in the second heat exchanger 31 that functions as an evaporator of the refrigerant. For this reason, if a temperature sensor is provided in the second heat exchanger 31, the temperature of the refrigerant detected by this temperature sensor may be used as the evaporation temperature of the refrigerant.

(5-2) Heating operation Heating operation is performed by the first control unit 20c and the second control unit 35, which receive a heating operation command via the remote control 36, controlling the operation of the compressor 21, four-way switching valve 22, first expansion valve 24, first fan 25, second fan 32, second expansion valve 33, etc., which are components of the heat source unit 20 and the utilization unit 30.

During heating operation, the four-way switching valve 22 is switched so that the first heat exchanger 23 functions as a refrigerant evaporator and the second heat exchanger 31 functions as a refrigerant condenser (the state shown by the dashed line of the four-way switching valve 22 in Figure 1).

In the refrigerant circuit 10 in this state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21, compressed to the high pressure in the refrigeration cycle, and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the second heat exchanger 31 through the four-way switching valve 22 and the gas side communication pipe 5. The high-pressure refrigerant sent to the second heat exchanger 31 exchanges heat with the indoor air supplied by the second fan 32 in the second heat exchanger 31 and condenses. As a result, the indoor air is heated and blown out into the room. The high-pressure refrigerant condensed in the second heat exchanger 31 is depressurized by the second expansion valve 33 and flows out of the utilization unit 30. The refrigerant flowing out of the utilization unit 30 is sent to the first expansion valve 24 through the liquid side communication pipe 6 and depressurized to the low pressure in the refrigeration cycle. The low-pressure refrigerant depressurized in the first expansion valve 24 is sent to the first heat exchanger 23. The low-pressure refrigerant sent to the first heat exchanger 23 evaporates in the first heat exchanger 23 by exchanging heat with the outdoor air supplied by the first fan 25. The low-pressure refrigerant evaporated in the first heat exchanger 23 is sucked back into the compressor 21 through the four-way switching valve 22 and the receiver 26. In this way, in the heating operation, the first control unit 20c and the second control unit 35 operate to circulate the refrigerant sealed in the refrigerant circuit 10 through the compressor 21, the second heat exchanger 31, the second expansion valve 33, the first expansion valve 24, and the first heat exchanger 23 in that order.

During heating operation, the first control unit 20c and the second control unit 35 perform capacity control to control the capacity of the compressor 21 so that the condensation temperature of the refrigerant in the refrigerant circuit 10 approaches a predetermined target condensation temperature. The capacity control of the compressor 21 is performed by controlling the rotation speed (frequency) of the compressor motor. The condensation temperature of the refrigerant is obtained by converting the discharge pressure detected by the discharge pressure sensor 61 into the saturation temperature of the refrigerant. The condensation temperature of the refrigerant means a temperature obtained by converting the pressure (condensation pressure of the refrigerant in the refrigerant circuit 10) representing the high-pressure refrigerant flowing from the discharge side of the compressor 21 to the first expansion valve 24 via the second heat exchanger 31 into the saturation temperature of the refrigerant during heating operation, or the saturation temperature of the refrigerant in the second heat exchanger 31 that functions as a condenser of the refrigerant. For this reason, if a temperature sensor is provided in the second heat exchanger 31, the temperature of the refrigerant detected by this temperature sensor may be used as the condensation temperature of the refrigerant.

(6) Refrigerant Leakage Detection Method Next, a refrigerant leakage detection method according to the present embodiment will be described.

When constructing the refrigeration cycle device 1, first, as shown in Figs. 3 and 4, the refrigerant circuit 10 formed by connecting the heat source unit 20 and the utilization unit 30 with the connecting pipes 5 and 6 is filled with a first filling amount of refrigerant that is less than the target filling amount (step S1). This step (S1) is performed, for example, as follows.

Specifically, a heat source unit 20 is prepared that is filled with a refrigerant equal to or less than a first fill amount as the initial fill amount. Here, a heat source unit 20 is prepared that is filled with a refrigerant that is less than the first fill amount, for example, 50% of the target fill amount, as the initial fill amount. Then, this heat source unit 20 is connected to a plurality of utilization units 30 via a liquid side communication pipe 6 and a gas side communication pipe 5. This allows the formation of a refrigerant circuit 10 that is filled with an initial fill amount of refrigerant. After that, the refrigerant circuit 10 is filled with refrigerant up to the first refrigerant amount. Here, an additional 20% of the target fill amount of refrigerant is filled, thereby filling the refrigerant circuit 10 with 70% of the target fill amount as the first fill amount.

The method of filling the additional refrigerant is not particularly limited, but for example, it is performed manually as follows. The container filled with the refrigerant to be added is connected to the charge port of the heat source unit 20. Here, the charge port is provided in the gas side shutoff valve 28 or the liquid side shutoff valve 29. After that, the operator opens the refrigerant supply valve of the container and the charge port. Then, the compressor 21 is driven to circulate the refrigerant in the heat source unit 20 in the same manner as in cooling operation or heating operation. As a result, the refrigerant in the container flows into the refrigerant circuit 10 through the charge port. Here, the refrigerant flowing into the refrigerant circuit 10 through the charge port is sucked into the compressor 21 through the receiver 26. When the sum of the initial charge amount and the additional charge amount of the refrigerant filled in the refrigerant circuit 10 becomes the first charge amount, the operator closes the refrigerant supply valve of the container and the charge port. Note that the additional charge amount is calculated in advance taking into account the length of the connecting pipes 5 and 6, the number of utilization units 30, etc., and the container is filled while weighing.

Next, a first test operation is performed to circulate a first charge amount of refrigerant in the refrigerant circuit 10, and first test operation data is obtained (step S2). This step (S2) is performed, for example, as follows.

Specifically, when the first input unit 20b receives a command to perform the first test operation, the first control unit 20c cooperates with the second control unit 35 to operate each unit constituting the refrigeration cycle device 1, and circulates the first charge amount of refrigerant in the refrigerant circuit 10 so that all the utilization units 30 are in cooling operation or heating operation. When the first test operation is cooling operation, the first control unit 20c performs capacity control to control the capacity of the compressor 21 so that the evaporation temperature of the refrigerant in the refrigerant circuit 10 approaches a predetermined target evaporation temperature. The target evaporation temperature of the first test operation is the same as the target evaporation temperature when the normal operation is cooling operation. When the first test operation is heating operation, the first control unit 20c performs capacity control to control the capacity of the compressor 21 so that the condensation temperature of the refrigerant in the refrigerant circuit 10 approaches a predetermined target condensation temperature. The target condensation temperature of the first test operation is the same as the target condensation degree when the normal operation is heating operation. When the state of the refrigerant in the refrigerant circuit 10 stabilizes, the opening degree of the second expansion valve 33 of each utilization unit 30 when the first charge amount of refrigerant is circulated is acquired as the first trial operation data. When the first trial operation data is acquired, the compressor 21 is stopped. The first control unit 20c stores the first trial operation data in the first storage unit 20d.

Next, the refrigerant circuit 10 is filled with refrigerant until the target filling amount is reached (step S3). This step (S3) is performed, for example, as follows.

Specifically, the refrigerant circuit 10, which has been filled with the first filling amount of refrigerant, is filled with refrigerant equal to the difference between the target filling amount and the first filling amount. Here, an additional 30% of the target filling amount of refrigerant is charged, thereby filling the refrigerant circuit 10 with the target filling amount (100%) of refrigerant. The method of charging the additional refrigerant is the same as in the step (S1) of charging the first filling amount of refrigerant.

Next, a final test run is performed to circulate the target charge amount of refrigerant in the refrigerant circuit 10, and final test run data is obtained (step S4). This step (S4) is performed, for example, as follows.

Specifically, when the first input unit 20b receives a command to perform the final test run, the first control unit 20c cooperates with the second control unit 35 to operate each unit constituting the refrigeration cycle device 1, and circulates the target charge amount of refrigerant in the refrigerant circuit 10 so that all the utilization units 30 are in cooling operation or heating operation. If the first test run is cooling operation, the final test run is also cooling operation, and if the first test run is heating operation, the final test run is also heating operation. When the final test run is cooling operation, the first control unit 20c performs capacity control to control the capacity of the compressor 21 so that the evaporation temperature of the refrigerant in the refrigerant circuit 10 approaches the target evaporation temperature. The target evaporation temperature of the final test run is the same as the target evaporation temperature during cooling operation as normal operation. When the final test run is heating operation, the first control unit 20c performs capacity control to control the capacity of the compressor 21 so that the condensation temperature of the refrigerant in the refrigerant circuit 10 approaches the target condensation temperature. The target condensation temperature for the final test run is the same as the target condensation degree during normal heating operation. When the state of the refrigerant in the refrigerant circuit 10 stabilizes, the opening degree of the second expansion valve 33 of each utilization unit 30 when the target charge amount of refrigerant is circulated is acquired as the final test run data. When the final test run data is acquired, the compressor 21 is stopped. The first control unit 20c stores the final test run data in the first storage unit 20d.

Next, normal operation data is acquired during normal operation after the target charge amount is charged into the refrigerant circuit 10 (step S5). As described above, normal operation is heating operation, cooling operation, etc., selected by the user via the remote control 36.

Next, based on the normal operation data and the first test operation data, it is determined whether or not there is a refrigerant leak from the refrigerant circuit 10 (step S6). In the determination step (S6) of this embodiment, it is determined whether or not there is a refrigerant leak from the refrigerant circuit 10 based on the normal operation data, the first test operation data, and the final operation data. The step (S5) of acquiring normal operation data and the step (S6) of determining are performed, for example, as follows.

Specifically, the first control unit 20c acquires data continuously during normal operation, and regards the data when conditions similar to those of the first test operation are satisfied as normal operation data. Here, the first control unit 20c regards the data acquired when all the utilization units 30 are in the same cooling or heating operation as in the first test operation as normal operation data. In addition, as normal operation data, the first control unit 20c acquires the opening degree of the second expansion valve 33 of each utilization unit 30 during normal operation, etc. Then, the first control unit 20c reads out the first test operation data from the first storage unit 20d, compares the normal operation data with the first test operation data, and determines that refrigerant has leaked from the refrigerant circuit 10 when the normal operation data is in a state similar to the first test operation data. Here, the first control unit 20c reads out the first test operation data and the final test operation data from the first storage unit 20d, compares the normal operation data, the first test operation data, and the final test operation data, and determines that refrigerant has leaked from the refrigerant circuit 10 when the normal operation data is closer to the first test operation data than the final test operation data. For example, the first control unit 20c determines that refrigerant has leaked from the refrigerant circuit 10 when the change over time in the opening degree of the second expansion valve 33 as the normal operation data approaches the opening degree of the second expansion valve 33 as the first test operation data from the opening degree of the second expansion valve 33 as the final test operation data.

Here, an example of the judgment method of the first control unit 20c in the judgment step (S6) is given. Assume that the first test run and normal run are cooling runs with a constant target evaporation temperature. In this case, the first test run has a smaller refrigerant amount than the target charge amount, and the opening degree of the second expansion valve 33 is larger than when the target charge amount of refrigerant is circulating due to the lower evaporation temperature. Therefore, the first control unit 20c judges that refrigerant is leaking when the opening degree of the second expansion valve 33 as the normal operation data increases so as to approach the opening degree of the second expansion valve 33 as the first test run data.

If the first control unit 20c determines in the determination step (S6) that there is no refrigerant leakage, it continues normal operation in response to a request from the user, and appropriately performs the step (S5) of acquiring normal operation data and the step (S6) of determining. On the other hand, if the first control unit 20c determines in the determination step (S6) that there is a refrigerant leakage, it transmits this to the server 40. The server 40 then notifies the user's information device 50 (step S7).

(7) Features (7-1)
The refrigerant leakage determination method of this embodiment includes the following steps. A first charge amount of refrigerant, which is less than a target charge amount, is filled into the refrigerant circuit 10 formed by connecting the heat source unit 20 and the utilization unit 30 with the communication pipes 5 and 6 (step S1). Then, a first test operation is performed to circulate the first charge amount of refrigerant in the refrigerant circuit 10, and first test operation data is acquired (step S2). Then, after the acquisition step (S2), the refrigerant circuit 10 is filled with refrigerant until the target charge amount is reached (step S3). Then, during normal operation after the target charge amount is filled into the refrigerant circuit 10, normal operation data is acquired (step S5). Then, based on the normal operation data and the first test operation data, it is determined whether or not there is a refrigerant leak from the refrigerant circuit 10 (step S6).

According to the refrigerant leakage determination method of this embodiment, a first trial operation is performed in which a first charge amount of refrigerant, which is less than the target charge amount, is circulated, and first trial operation data is obtained. This first trial operation data is data showing the behavior when the refrigerant leaks. Therefore, by comparing the normal operation data obtained during normal operation after the target charge amount is filled with the first trial operation data, it is possible to determine whether or not the refrigerant is leaking from the refrigerant circuit 10, regardless of the installation location, piping length, etc. of the refrigeration cycle device 1 including the heat source unit 20, the utilization unit 30, and the connecting piping 5, 6. Therefore, in the refrigerant leakage determination method of this embodiment, it is not necessary to perform a special operation under constant conditions in order to determine the refrigerant leakage, and the refrigerant leakage can be determined during normal operation. In addition, in the refrigerant leakage determination method of this embodiment, the refrigerant leakage can be determined by comparing the normal operation data with the first trial operation data without considering the installation location, piping length, etc., so that the accuracy of the determination can be improved.

The refrigerant leakage determination method of this embodiment further includes a step (S4) of performing a final test run in which a target charge amount of refrigerant is circulated in the refrigerant circuit 10, and acquiring final test run data.

(7-2)
The refrigeration cycle apparatus 1 of this embodiment is a refrigeration cycle apparatus including a heat source unit 20, a utilization unit 30, and communication pipes 5 and 6 connecting the heat source unit 20 and the utilization unit 30. The refrigeration cycle apparatus 1 includes a refrigerant circuit 10 and a first control unit 20c. The refrigerant circuit 10 is formed by connecting the heat source unit 20 and the utilization unit 30 with the communication pipes 5 and 6. The first control unit 20c controls the operation of the refrigerant circuit 10. The first control unit 20c performs a first test operation in which a first charge amount of refrigerant that is less than a target charge amount is circulated in the refrigerant circuit 10, and acquires first test operation data.

According to the refrigeration cycle device 1 of this embodiment, the first control unit 20c performs a first trial operation in which a first charge amount of refrigerant, which is less than the target charge amount, is circulated, and acquires first trial operation data. This first trial operation data is data indicating the behavior when the refrigerant leaks. Therefore, by comparing the normal operation data acquired during normal operation after the target charge amount is filled with the first trial operation data by the first control unit 20c, it is possible to determine whether or not the refrigerant is leaking from the refrigerant circuit 10, regardless of the installation location of the refrigeration cycle device 1, the piping length, etc. Therefore, in the refrigeration cycle device 1 of this embodiment, it is not necessary to perform a special operation to keep the conditions constant in order to determine the refrigerant leakage, and the refrigerant leakage can be determined during normal operation. In addition, in the refrigeration cycle device 1 of this embodiment, the first control unit 20c can determine the refrigerant leakage by comparing the normal operation data with the first trial operation data without considering the installation location, the piping length, etc., so that the accuracy of the determination can be improved.

The first control unit 20c of the refrigeration cycle device 1 of this embodiment has multiple test operation modes (in this embodiment, the first test operation and the final test operation) and acquires test operation data for each of the multiple test operations.

(8) Modifications (8-1) Modification 1
In the above-described embodiment, the test operation in which a refrigerant filling amount less than the target filling amount is circulated is the first test operation only, but this is not limited to this. The refrigerant leakage determination method and refrigeration cycle device 1 of the present disclosure may perform multiple test operations in which a refrigerant filling amount less than the target filling amount is circulated. The refrigerant leakage determination method and refrigeration cycle device of this modified example perform a second test operation in which a refrigerant filling amount less than the target filling amount is circulated in addition to the first test operation.

(8-1-1) Refrigeration Cycle Apparatus The first control unit 20c of this modification acquires second test operation data by performing a second test operation in which a second charge amount of refrigerant, which is greater than the first charge amount and less than the target charge amount, is circulated in the refrigerant circuit 10. The second charge amount is, for example, 50% or more and less than 100% of the target charge amount, and is 90% of the target charge amount in this modification.

Specifically, the first control unit 20c of this modified example has three modes: a first test operation in which a first charge amount of refrigerant that is less than the target charge amount is circulated; a second test operation in which a second charge amount of refrigerant that is more than the first charge amount and less than the target charge amount is circulated; and a final test operation in which the target charge amount of refrigerant is circulated. The first test operation and final test operation modes are the same as those of the above embodiment. The added second test operation will be described below.

When the first input unit 20b receives a command to perform the second test run, the first control unit 20c operates each part of the heat source unit 20 to perform the second test run, and sends a command to the second control unit 35 of the utilization unit 30 to operate each part of the utilization unit 30. The first control unit 20c then acquires second test run data during the second test run. The second test run data is, for example, the opening degree of the second expansion valve 33 of each utilization unit 30. The first control unit 20c then stores the acquired second test run data in the first storage unit 20d.

The first control unit 20c also acquires normal operation data during normal operation, and determines whether or not refrigerant is leaking from the refrigerant circuit 10 based on the normal operation data, the first trial operation data, the second trial operation data, and the final trial operation data. Here, the first control unit 20c compares the normal operation data when conditions similar to those of the first trial operation are satisfied during normal operation, with the first trial operation data, the second trial operation data, and the final trial operation data, and determines that refrigerant has leaked from the refrigerant circuit 10 when the final trial operation data is in a state similar to the first trial operation data or the second trial operation data.

The first test operation data, the second test operation data, and the final test operation data acquired by the first control unit 20c are, for example, data regarding the opening degree of each second expansion valve 33 when all of the multiple utilization units 30 are performing cooling operation. The first control unit 20c acquires the opening degree of each second expansion valve 33 as normal operation data when all of the utilization units 30 are performing cooling operation during normal operation. Then, the first control unit 20c compares the opening degree of each second expansion valve 33 as the first test operation data, the opening degree of each second expansion valve 33 as the second test operation data, the opening degree of each second expansion valve 33 as the final test operation data, and the opening degree of each second expansion valve 33 as the normal operation data. Specifically, the presence or absence of refrigerant leakage is determined by calculating how close the opening degree of each second expansion valve 33 during normal operation is to the opening degree of each second expansion valve 33 during the first test operation and the opening degree of each second expansion valve 33 during the second test operation from the opening degree of each second expansion valve 33 during the final test operation. In addition, the first control unit 20c considers the change in the opening degree of each second expansion valve 33 from the first test operation data to the opening degree of each second expansion valve 33 during the second test operation data. The change in the opening degree of the second expansion valve is, for example, linear or quadratic. Note that the target evaporation temperature is the same during the first test operation, the final test operation, and normal operation.

In addition, the first input unit 20b in this modified example further includes a button for receiving a command to perform the second test run.

(8-1-2) Refrigerant Leakage Determination Method The refrigerant leakage determination method of this modified example is basically similar to the refrigerant leakage determination method of the above-described embodiment, but differs in that it further includes a step (S11) of filling a second filling amount of refrigerant and a step (S12) of obtaining second trial operation data, as shown in FIG. 5 .

Specifically, similar to the above embodiment, a step (S1) of charging a first refrigerant amount and a step (S2) of acquiring first trial operation data are carried out. Next, the refrigerant circuit 10 is charged with a second charge amount of refrigerant that is greater than the first charge amount and less than the target charge amount (step S11). This step (S11) is carried out, for example, as follows.

The refrigerant circuit 10, which has been filled with the first amount of refrigerant, is filled with the difference between the second amount (90%) and the first amount (70%) of refrigerant. Here, the second amount (90%) of refrigerant is filled into the refrigerant circuit 10 by additionally filling 20% of the target amount of refrigerant. The method of filling the additional refrigerant is the same as in the step (S1) of filling the first amount of refrigerant.

Next, a second test operation is performed to circulate a second charge amount of refrigerant in the refrigerant circuit 10, and second test operation data is obtained (step S12). This step (S12) is performed, for example, as follows.

Specifically, when the first input unit 20b receives a command to perform the second test operation, the first control unit 20c cooperates with the second control unit 35 to operate each unit constituting the refrigeration cycle device 1, and circulates the second charge amount of refrigerant in the refrigerant circuit 10 so that all the utilization units 30 are in cooling operation or heating operation. If the first test operation is cooling operation, the second test operation is also cooling operation, and if the first test operation is heating operation, the second test operation is also heating operation. When the second test operation is cooling operation, the first control unit 20c performs capacity control to control the capacity of the compressor 21 so that the evaporation temperature of the refrigerant in the refrigerant circuit 10 approaches the target evaporation temperature. The target evaporation temperature of the second test operation is the same as the target evaporation temperature during cooling operation as normal operation. When the second test operation is heating operation, the first control unit 20c performs capacity control to control the capacity of the compressor 21 so that the condensation temperature of the refrigerant in the refrigerant circuit 10 approaches the target condensation temperature. The target condensation temperature for the second test operation is the same as the target condensation degree during heating operation as normal operation. When the state of the refrigerant in the refrigerant circuit 10 stabilizes, the opening degree of the second expansion valve 33 of each utilization unit 30 when the second charge amount of refrigerant is circulated is acquired as the second test operation data. When the first control unit 20c acquires the second test operation data, it stops the compressor 21. The first control unit 20c stores the second test operation data in the first storage unit 20d.

Next, refrigerant is filled into the refrigerant circuit 10 until the target filling amount is reached (step S3). In this step (S3), the refrigerant circuit 10 filled with the second filling amount of refrigerant is filled with the difference between the target filling amount and the second filling amount. Here, the container is weighed and an additional refrigerant amount of 10% of the target filling amount is added as a previously calculated additional amount of refrigerant, thereby filling the refrigerant circuit 10 with the target filling amount.

Next, similar to the first embodiment, a process (S4) is carried out to obtain the final test run data.

Next, during normal operation after the target filling amount is filled into the refrigerant circuit 10, normal operation data is acquired (step S5). Next, based on the normal operation data, the first test operation data, and the second test operation data, it is determined whether or not there is a refrigerant leak from the refrigerant circuit 10 (step S6). The process of acquiring normal operation data (S5) and the process of determining (S6) are performed, for example, as follows.

Specifically, as in the above-described embodiment, the first control unit 20c acquires normal operation data. Then, the first control unit 20c reads out the first test operation data, the second test operation data, and the final test operation data from the first storage unit 20d, and compares the normal operation data with the first test operation data, the second test operation data, and the final test operation data. When the normal operation data is in a state similar to the first test operation data or the second test operation data, it is determined that refrigerant has leaked from the refrigerant circuit 10. For example, the first control unit 20c determines that refrigerant has leaked from the refrigerant circuit 10 when the change over time in the opening degree of the second expansion valve 33 as the normal operation data approaches the opening degree of the second expansion valve 33 as the second test operation data or the opening degree of the second expansion valve 33 as the first test operation data from the opening degree of the second expansion valve 33 as the final test operation data. Here, the first control unit 20c determines whether or not there is a refrigerant leak from the refrigerant circuit 10 based on the first test run data, the second test run data, and the final test run data, based on the change in the opening degree of the second expansion valve 33.

(8-1-3) Features The refrigerant leakage determination method of this modified example further includes the following steps: Filling the refrigerant circuit 10 with a second charge amount that is greater than the first charge amount and less than a target charge amount (S11). Performing a second test operation in which the second charge amount of refrigerant is circulated through the refrigerant circuit 10, and acquiring second test operation data (S12). In the determination step (S6), the presence or absence of refrigerant leakage from the refrigerant circuit 10 is determined based on the normal operation data, the first test operation data, and the second test operation data.

Here, a second test operation is performed to circulate a second charge amount of refrigerant between the first charge amount and the target charge amount, and second test operation data is obtained. This second test operation data indicates the behavior when refrigerant leaks, and is different from the first test operation data. Therefore, by comparing the normal operation data obtained during normal operation after the target charge amount is filled with the first test operation data and the second test operation data, the accuracy of determining whether or not there is a refrigerant leak can be improved.

In this modified refrigeration cycle device 1, the first control unit 20c performs a second test operation in which a second charge amount of refrigerant, which is greater than the first charge amount and less than the target charge amount, is circulated in the refrigerant circuit 10, and acquires second test operation data.

Here, the first control unit 20c performs a second test operation in which a second filling amount of refrigerant between the first filling amount and the target filling amount is circulated, and acquires second test operation data. This second test operation data indicates the behavior when refrigerant leaks, and is different from the first test operation data. Therefore, by comparing the normal operation data acquired during normal operation after filling the target filling amount with the first test operation data and the second test operation data, it is possible to improve the accuracy of determining whether or not there is a refrigerant leak.

(8-2) Modification 2
In the above embodiment, the first test run is performed to circulate the first charge amount of refrigerant that is equal to or greater than 50% of the target charge amount. However, the present modification further includes a test run to circulate the refrigerant that is less than 50% of the target charge amount.

Specifically, the first control unit 20c of the refrigeration cycle device of this modified example performs a third test operation in which a third charge amount of refrigerant, which is less than the first charge amount, is circulated in the refrigerant circuit 10, and acquires third test operation data. The third charge amount is, for example, less than 50% of the target charge amount, and in this modified example, is 30% of the target charge amount.

In addition, the refrigerant leakage determination method of this modified example further includes a step of filling the refrigerant circuit 10 with a third refrigerant amount less than the first filling amount prior to the step (S1) of filling the refrigerant with the first refrigerant amount, and a step of performing a third test operation in which the third filling amount of refrigerant is circulated in the refrigerant circuit 10 to obtain third test operation data.

Specifically, in the process of filling the third fill amount of refrigerant, a heat source unit 20 is prepared that is filled with refrigerant equal to or less than the third fill amount as an initial fill amount. Then, this heat source unit 20 is connected to a plurality of utilization units 30 by communication pipes 5, 6. This makes it possible to form a refrigerant circuit 10 that is filled with an initial fill amount of refrigerant. If the initial fill amount is less than the third fill amount, the refrigerant circuit 10 is filled with refrigerant up to the third refrigerant amount.

In the process of acquiring the third test run data, a third test run is conducted in a similar manner to the first test run and the final test run to acquire the third test run data.

In the determination step (S6) shown in FIG. 5, the presence or absence of refrigerant leakage from the refrigerant circuit 10 is determined based on the normal operation data, the first to third test operation data, and the final test operation data.

As in this modified example, the refrigerant leakage determination method and refrigeration cycle device 1 disclosed herein may perform a trial run in which an arbitrary amount of refrigerant less than the target amount is circulated as appropriate.

(8-3) Modification 3
In the above embodiment, after the first test operation data is acquired, the compressor 21 is stopped (step S2), refrigerant is additionally charged (step S3), and a final test operation is performed (step S4). However, this is not limited to this. In this modified example, after the first test operation data is acquired, the compressor 21 is not stopped (step S2), refrigerant is additionally charged (step S3), and a final test operation is performed (step S4).

Specifically, after a first test run is performed in which a first charge amount of refrigerant, which is less than the target charge amount, is circulated, additional refrigerant is charged without stopping the compressor 21, and when the target charge amount is reached, a final test run is performed by the first input unit 20b, and final test run data is obtained.

This modification can also be applied when performing test runs with three or more different filling volumes, as in Modifications 1 and 2. This modification can reduce the time required for multiple test runs.

(8-4) Modification 4
In the above-described embodiment, an example of using the opening degree of the second expansion valve 33 as a method for determining the presence or absence of refrigerant leakage has been described, but the present disclosure does not limit the present disclosure. In the refrigerant leakage determination method and the refrigeration cycle device 1 of the present disclosure, the opening degree of the second expansion valve 33, the outlet superheat degree of the evaporator (second heat exchanger 31 or first heat exchanger 23), the outlet subcooling degree of the condenser (first heat exchanger 23 or second heat exchanger 31), the liquid pipe temperature detected at the liquid pipe outlet of the utilization unit 30, and the like may be used alone or in combination as a method for determining the presence or absence of refrigerant leakage. In other words, the first test run data, the final test run data, and the normal operation data are at least one of the following data: the opening degree of the second expansion valve 33, the outlet superheat degree of the evaporator (second heat exchanger 31 or first heat exchanger 23), the outlet subcooling degree of the condenser (first heat exchanger 23 or second heat exchanger 31), and the liquid pipe temperature detected at the liquid pipe outlet of the utilization unit 30. The first control unit 20c determines that refrigerant is leaking when the degree of superheat at the evaporator outlet is large, the degree of subcooling at the condenser outlet is small, or the liquid pipe temperature detected at the liquid pipe outlet of the utilization unit 30 is low, so that the normal operation data approaches the first trial operation data.

The degree of supercooling can be calculated by, for example, converting the refrigerant pressure detected by the discharge pressure sensor 61 into the saturation temperature of the refrigerant, and subtracting this saturation temperature from the refrigerant temperature detected by the liquid side temperature sensor 65. The degree of superheat can be calculated by, for example, converting the refrigerant pressure detected by the suction pressure sensor 63 into the saturation temperature of the refrigerant, and subtracting the refrigerant temperature detected by the suction temperature sensor 64 from this saturation temperature.

(8-5) Modification 5
In the above-described embodiment, the charging of the refrigerant is performed manually, but the present invention is not limited to this and may be performed automatically.

(8-6) Modification 6
In the above-described embodiment, the refrigeration cycle apparatus 1 is described as an example in which the plurality of utilization units 30 can individually perform cooling or heating operation, but is not limited thereto. In the refrigeration cycle apparatus of this modification, the plurality of utilization units 30 cannot individually perform cooling or heating operation. In this case, for example, a second expansion valve 33 common to the plurality of utilization units 30 is provided.

(8-7) Modification 7
In the embodiment described above, the refrigeration cycle apparatus 1 includes three utilization units 30, but there is no limitation on the number of utilization units 30. The refrigeration cycle apparatus of the present disclosure may include two or more utilization units 30, or may include one utilization unit 30.

(8-8) Modification 8
In the above-described embodiment, the refrigeration cycle apparatus 1 performing cooling operation and heating operation has been described as an example, but the refrigeration cycle apparatus of the present disclosure is not limited thereto, and may further perform a dehumidification operation, etc. The refrigeration cycle apparatus of this modification is an air conditioning apparatus dedicated to cooling.

(8-9) Modification 9
In the above-described embodiment, an air conditioner has been described as an example of the refrigeration cycle apparatus 1, but the refrigeration cycle apparatus of the present disclosure may be a hot water supply apparatus, a floor heating apparatus, a refrigeration apparatus, or the like.

Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure as set forth in the claims.

1: Refrigeration cycle device 5, 6: Interconnecting pipe 10: Refrigerant circuit 20: Heat source unit 20c: First control unit (control unit)
30: utilization unit 35: second control unit

International Publication No. 2015/004747

Claims (4)

A step (S1) of filling a refrigerant circuit (10) formed by connecting a heat source unit (20) and a utilization unit (30) with a first filling amount of refrigerant that is less than a target filling amount;
A step (S2) of performing a first test operation in which the first charge amount of refrigerant is circulated in the refrigerant circuit to acquire first test operation data;
After the acquiring step, a step (S3) of charging the refrigerant into the refrigerant circuit until the target charging amount is reached;
A step (S5) of acquiring normal operation data during normal operation after the target filling amount is filled into the refrigerant circuit;
A step (S6) of determining whether or not a refrigerant leaks from the refrigerant circuit by comparing the normal operation data with the first test operation data acquired during the first test operation ;
Equipped with
The refrigerant leakage determination method, wherein the target evaporation temperature or the target condensation temperature in the first test operation and the normal operation are the same. A step (S11) of charging the refrigerant circuit with a second charge amount of refrigerant, the second charge amount being greater than the first charge amount and less than the target charge amount;
A step (S12) of performing a second test operation in which the second charge amount of refrigerant is circulated in the refrigerant circuit to acquire second test operation data;
Further equipped with
In the determining step, the normal operation data is compared with the first test operation data acquired during the first test operation , and the second test operation data acquired during the second test operation to determine whether or not there is a leakage of refrigerant from the refrigerant circuit.
The refrigerant leakage determination method according to claim 1 . A refrigeration cycle apparatus comprising a heat source unit (20), a utilization unit (30), and communication piping (5, 6) connecting the heat source unit and the utilization unit,
a refrigerant circuit (10) formed by connecting the heat source unit and the utilization unit with the communication pipe;
A control unit (20c) for controlling an operation of the refrigerant circuit;
Equipped with
The control unit performs a first test operation in which a first charge amount of refrigerant that is less than a target charge amount is circulated in the refrigerant circuit, and acquires first test operation data;
The target evaporation temperature or the target condensation temperature in the first test operation is the same as the target evaporation temperature or the target condensation temperature in normal operation after the refrigerant circuit is charged with the target charge amount,
The control unit determines whether or not refrigerant is leaking from the refrigerant circuit by comparing normal operation data acquired during the normal operation with the first test operation data acquired during the first test operation . The control unit is
performing a second test operation in which a second charge amount of refrigerant, the second charge amount being greater than the first charge amount and less than the target charge amount, is circulated in the refrigerant circuit, and acquiring second test operation data;
determining whether or not there is a leakage of refrigerant from the refrigerant circuit by comparing the normal operation data, the first test operation data acquired during the first test operation, and the second test operation data acquired during the second test operation;
The refrigeration cycle device according to claim 3.

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