JP2023148361A - Refrigeration cycle device and refrigerant leakage determination method - Google Patents

Abstract

To reduce a constriction of timing for determining whether or not refrigerant leakage occurs in a state of being suitable for a determination of the refrigerant leakage, in a refrigeration cycle device.SOLUTION: An air-conditioning device 10 comprises a compressor 30, an outdoor heat exchanger 31, an indoor heat exchanger 25, a refrigerant circuit 40 including expansion valves 24 and 34, a refrigerant pressure sensor 35 and a refrigerant temperature sensor 36, and a control unit 50 for controlling the refrigerant circuit 40, and performing the determination processing of the presence or absence of the refrigerant leakage of the refrigerant circuit 40. The control unit 50 can operate the air-conditioning device 10 at a first mode M1 when a normal cooling operation is performed, and at a second mode M2 when the determination processing is performed. The control unit 50 lowers a second overcooling degree SC2 at an outlet of the outdoor heat exchanger 31 at the second mode M2 compared with a first overcooling degree SC1 at the first mode M1, and makes a second evaporation temperature T2 of the indoor heat exchanger 25 at the second mode M2 approximate a first evaporation temperature T1 at the first mode M1.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a refrigeration cycle device and a method for determining refrigerant leakage.

Conventionally, for a refrigeration cycle device that adjusts the temperature of a target space, a technique for determining whether there is a refrigerant leak in a refrigerant circuit is known (see Patent Document 1). In the refrigeration cycle device, the refrigerant circuit is controlled by the control device so that the degree of subcooling at the condenser outlet is lowered (hereinafter also referred to as "a state suitable for determining refrigerant leakage"). To accurately determine the presence or absence of a leak.

Japanese Patent Application Publication No. 2016-099059

However, when the refrigeration cycle device is in a state suitable for determining refrigerant leakage, the supply air temperature may decrease, and the user's comfort level in the target space may decrease. Therefore, in the refrigeration cycle device, the timing at which the presence or absence of refrigerant leakage can be determined in a state suitable for determining refrigerant leakage is when there is no need to perform air conditioning on the target space, or when there is no person in the target space. This was limited to when no one was around (for example, at night).

The present disclosure aims to reduce restrictions on the timing of determining the presence or absence of refrigerant leakage in a state suitable for determining refrigerant leakage in a refrigeration cycle device.

(1) The refrigeration cycle device of the present disclosure includes a refrigerant circuit including a compressor, a condenser, an evaporator, and a valve connected by refrigerant piping, and measures the temperature or pressure of the refrigerant at a predetermined location in the refrigerant circuit. and a sensor that controls the refrigerant circuit by adjusting the opening degree of the valve and the rotation speed of the compressor based on the measured value of the sensor, and also executes a process for determining the presence or absence of refrigerant leakage in the refrigerant circuit. a control unit capable of operating the refrigeration cycle device in a first mode when performing normal cooling operation and a second mode when executing the determination process; The control unit lowers a second degree of supercooling of the refrigerant at the outlet of the condenser in the second mode compared to a first degree of supercooling of the refrigerant at the outlet of the condenser in the first mode, and A second evaporation temperature of the refrigerant in the evaporator in the second mode is brought closer to a first evaporation temperature of the evaporator in the first mode.

According to the refrigeration cycle device of the present disclosure, when the operation in the second mode is performed, it is possible to suppress a decrease in the temperature of the air that has passed through the evaporator, so that the target space to which the air is supplied can be suppressed. Even when the user is present in the target space, the driving in the second mode can be performed without compromising the comfort of the user. As a result, it is possible to reduce restrictions on the timing of determining the presence or absence of refrigerant leakage in a state suitable for determination of refrigerant leakage regarding the refrigeration cycle device.

(2) In the refrigeration cycle device of the present disclosure, the valve includes a first valve that adjusts the pressure of refrigerant at the outlet of the condenser, and a second valve that adjusts the pressure of the refrigerant at the inlet of the evaporator. The control unit controls the first valve to lower the second degree of supercooling compared to the first degree of supercooling, and controls the opening degree of the second valve and the rotation of the compressor. It is preferable that the second evaporation temperature be brought close to the first evaporation temperature by controlling the number of evaporation temperatures.

In this case, with respect to the refrigeration cycle device, it is possible to reduce restrictions on the timing of determining the presence or absence of refrigerant leakage in a state suitable for determination of refrigerant leakage.

(3) In the refrigeration cycle device of the present disclosure, it is preferable that the refrigerant circuit includes a tank that stores surplus refrigerant in the refrigerant circuit.

In this case, with respect to a refrigeration cycle device having a tank for storing surplus refrigerant in a refrigerant circuit, restrictions on the timing of determining the presence or absence of refrigerant leakage in a state suitable for determination of refrigerant leakage can be reduced.

(4) In the refrigeration cycle device of the present disclosure, the control unit periodically operates the refrigeration cycle device in the second mode, and the determination unit operates while the refrigeration cycle device is operating in the second mode. It is preferable to execute the determination process in the following manner.

In this case, the presence or absence of refrigerant leakage of the refrigeration cycle device can be periodically determined with high accuracy.

(5) The refrigeration cycle device of the present disclosure preferably further includes a display unit that displays information regarding the operation mode of the refrigeration cycle device.

In this case, the display unit can inform the user that the refrigeration cycle device is being operated in the second mode.

(6) The refrigeration cycle device of the present disclosure includes a first setting value related to the timing to start operation of the refrigeration cycle device in the second mode, and a first setting value related to the timing to end the operation of the refrigeration cycle device in the second mode. It is preferable that the refrigeration cycle apparatus further includes an operation section capable of setting two set values, and the control section controls the refrigeration cycle device based on the set first set value and the second set value.

In this case, the user can select the timing to execute the second mode. Furthermore, the user can select the period during which the second mode is executed, thereby allowing the user to select the accuracy of determining whether there is a refrigerant leak in the refrigeration cycle device.

(7) The refrigerant leak determination method of the present disclosure includes a refrigerant circuit including a compressor, a condenser, an evaporator, and a valve connected by refrigerant piping, and the temperature or pressure of the refrigerant at a predetermined location in the refrigerant circuit. a sensor that measures, and a process for controlling the refrigerant circuit by adjusting the opening degree of the valve and the rotation speed of the compressor based on the measured value of the sensor, and determining the presence or absence of refrigerant leakage in the refrigerant circuit. A method for determining refrigerant leakage in a refrigeration cycle apparatus, comprising: a first mode when performing normal cooling operation; and a first mode when performing the determination process. The refrigeration cycle device can be operated in two modes, and a second degree of supercooling of the refrigerant at the outlet of the condenser in the second mode is a first degree of supercooling of the refrigerant at the outlet of the condenser in the first mode. The second evaporation temperature of the refrigerant in the evaporator in the second mode is brought closer to the first evaporation temperature of the evaporator in the first mode.

According to the refrigerant leak determination method of the present disclosure, even if there is a user in the target space, operation in the second mode can be performed, and the presence or absence of refrigerant leak can be determined in a state suitable for refrigerant leak determination. Timing constraints can be reduced.

FIG. 1 is a schematic configuration diagram of a refrigeration cycle device of the present disclosure. FIG. 1 is a schematic configuration diagram of an air conditioner according to a first embodiment. FIG. 1 is a block diagram of an air conditioner according to a first embodiment. FIG. 3 is a flow diagram showing the flow of determination processing. FIG. 3 is a schematic configuration diagram of an air conditioner according to a second embodiment. FIG. 2 is a block diagram of an air conditioner according to a second embodiment.

Hereinafter, embodiments of a refrigeration cycle device will be described in detail with reference to the accompanying drawings.

[About the overall configuration of the refrigeration cycle device]
FIG. 1 is a schematic configuration diagram of a refrigeration cycle device of the present disclosure. FIG. 2 is a schematic configuration diagram of the air conditioner according to the first embodiment. FIG. 3 is a block diagram of the air conditioner according to the first embodiment. FIG. 1 shows an air conditioner 10 that is an embodiment of the refrigeration cycle device of the present disclosure. In the following description, the air conditioner 10 according to the first embodiment will be referred to as a first air conditioner 11, and the air conditioner 10 according to a second embodiment, which will be described later, will be referred to as a second air conditioner 12. In addition, in the following description, when simply calling "air conditioner 10", the structure common to the 1st air conditioner 11 and the 2nd air conditioner 12 is being demonstrated. Note that in this description, the refrigeration cycle device of the present disclosure will be explained using an air conditioner as an example, but the refrigeration cycle device of the present disclosure is not limited to the air conditioner, and the refrigeration cycle device of the present disclosure includes the following: Examples include refrigeration equipment, freezing equipment, etc.

The air conditioner 10 shown in FIGS. 1 and 2 adjusts the temperature of air in a space to be air-conditioned to a predetermined target temperature. The air conditioner 10 includes a heat source side unit (outdoor unit) 21 and a user side unit (indoor unit) 22. In this embodiment, a configuration in which one heat source side unit 21 is connected to one user side unit 22 is illustrated. However, the number of heat source side units 21 and usage side units 22 is not limited, and a configuration in which two or more usage side units 22 are connected to one heat source side unit 21 in parallel may be used. In addition, in the case of a configuration in which a plurality of user-side units 22 are connected to the heat source-side unit 21, a cooling/heating switching type heat pump type air conditioner may be used, or cooling and heating may be performed separately for each user-side unit 22. It may be a so-called cooling/heating free type air conditioner that can be switched individually.

The air conditioner 10 has a communication pipe 23. The communication pipe 23 circulates the refrigerant between the heat source side unit 21 and the usage side unit 22. The air conditioner 10 includes a compressor 30, a four-way switching valve 32, an outdoor heat exchanger 31, an outdoor expansion valve 34, a liquid closing valve 37a, an indoor expansion valve 24, an indoor heat exchanger 25, a gas closing valve 37b, and the like. The refrigerant circuit 40 includes a refrigerant pipe that connects the refrigerant. The refrigerant circuit 40 includes a gas refrigerant pipe 40G and a liquid refrigerant pipe 40L.

The user unit 22 includes an indoor expansion valve 24 and an indoor heat exchanger 25. The indoor expansion valve 24 and the indoor heat exchanger 25 constitute a part of the refrigerant circuit 40. The indoor expansion valve 24 is an electrically operated valve that can adjust the flow rate of refrigerant. The indoor heat exchanger 25 is a cross-fin tube type or microchannel type heat exchanger, and is used to exchange heat with indoor air.

The user unit 22 includes an indoor fan 26 and an indoor temperature sensor 27. The indoor fan 26 is configured to take indoor air into the user side unit 22, perform heat exchange between the taken air and refrigerant in the indoor heat exchanger 25, and then blow out the air indoors. be done. The indoor fan 26 includes a motor whose operating speed can be adjusted by inverter control. The indoor temperature sensor 27 detects the indoor temperature.

The heat source side unit 21 includes a compressor 30, a four-way switching valve 32, an outdoor heat exchanger 31, an outdoor expansion valve 34, a closing valve 37 (a liquid closing valve 37a and a gas closing valve 37b), and an accumulator 38. The compressor 30, the four-way switching valve 32, the outdoor heat exchanger 31, the outdoor expansion valve 34, the liquid shut-off valve 37a, and the gas shut-off valve 37b constitute a part of the refrigerant circuit 40. In the air conditioner 10, as expansion valves, an outdoor expansion valve 34 that adjusts the pressure of refrigerant at the outlet of the outdoor heat exchanger 31, and an indoor expansion valve 24 that adjusts the pressure of the refrigerant at the inlet of the indoor heat exchanger 25, Contains.

The compressor 30 sucks in low-pressure gaseous refrigerant and discharges high-pressure gaseous refrigerant. The compressor 30 includes a motor whose operating speed can be adjusted by inverter control. The compressor 30 is a variable capacity type (capacity variable type) whose capacity (capacity) can be changed by controlling the motor with an inverter. However, the compressor 30 may be of a constant capacity type. Although the air conditioner 10 of the present disclosure includes one compressor 30, the configuration of the heat source side unit in the refrigeration cycle device (air conditioner) of the present disclosure is not limited to this configuration. The configuration may include a compressor. In this case, the first compressor may be a variable capacity type, and the second compressor may be a constant capacity type.

The four-way switching valve 32 reverses the flow of refrigerant in the refrigerant pipe, and switches and supplies the refrigerant discharged from the compressor 30 to either the outdoor heat exchanger 31 or the indoor heat exchanger 25. Thereby, the air conditioner 10 can switch between cooling operation and heating operation.

The outdoor heat exchanger 31 is, for example, a cross-fin tube type or microchannel type heat exchanger, and is used to exchange heat with a refrigerant using air as a heat source. The outdoor expansion valve 34 is an electrically operated valve that can adjust the flow rate of refrigerant.

The liquid shutoff valve 37a and the gas shutoff valve 37b are manual on-off valves. The liquid shutoff valve 37a and the gas shutoff valve 37b block the flow of refrigerant in the gas refrigerant pipe 40G and the liquid refrigerant pipe 40L by closing, and allow the flow of refrigerant in the gas refrigerant pipe 40G and the liquid refrigerant pipe 40L by opening. do.

The accumulator 38 is a container that can store excess refrigerant present in the refrigerant circuit 40. The accumulator 38 is connected to the suction side piping of the compressor 30 and plays the role of separating liquid refrigerant from the gas-liquid two-layer refrigerant and flowing the gas refrigerant to the compressor 30. The heat source side unit 21 constituting the air conditioner 10 of the present disclosure is a so-called chargeless type outdoor unit, and the accumulator 38 has a capacity that can be accommodated when the connecting pipe 23 is set to the maximum allowable pipe length. A refrigerant is pre-filled. In the air conditioner 10 including such a heat source side unit 21, additional charging of refrigerant is not necessary if the length of the connecting pipe 23 is equal to or less than the maximum allowable pipe length.

The heat source side unit 21 includes an outdoor fan 33 , a plurality of refrigerant pressure sensors 35 , a plurality of refrigerant temperature sensors 36 , and an outside air temperature sensor 28 . The outdoor fan 33 includes a motor whose operating rotation speed can be adjusted by inverter control. The outdoor fan 33 takes outdoor air into the heat source unit 21 , exchanges heat between the taken air and the outdoor heat exchanger 31 , and then blows the air out of the heat source unit 21 . It is configured as follows.

The heat source side unit 21 includes a suction pressure sensor 35a and a discharge pressure sensor 35b as refrigerant pressure sensors 35. The suction pressure sensor 35a detects the pressure of refrigerant sucked into the compressor 30. The discharge pressure sensor 35b detects the pressure of refrigerant discharged from the compressor 30. Note that the heat source side unit 21 may further include refrigerant pressure sensors 35 other than these refrigerant pressure sensors 35 (suction pressure sensor 35a and discharge pressure sensor 35b).

The heat source side unit 21 includes a suction temperature sensor 36a, a discharge temperature sensor 36b, and a heat exchanger pipe temperature sensor 36c as refrigerant temperature sensors 36. The suction temperature sensor 36a detects the temperature of refrigerant sucked into the compressor 30. The discharge temperature sensor 36b detects the temperature of the refrigerant discharged from the compressor 30. The heat exchanger liquid pipe temperature sensor 36c detects the liquid pipe temperature of the outdoor heat exchanger 31. Note that the heat source side unit 21 may further include a refrigerant temperature sensor 36 other than these refrigerant temperature sensors 36 (the suction temperature sensor 36a, the discharge temperature sensor 36b, and the heat exchanger pipe temperature sensor 36c). The outside air temperature sensor 28 detects the temperature of outside air taken into the heat source side unit 21.

[About the control unit]
As shown in FIGS. 2 and 3, the air conditioner 10 includes a control section 50 that controls the operation of the air conditioner 10. In the following description, the control unit 50 of the first air conditioner 11 will be referred to as a first control unit 51. The first control section 51 includes an indoor control section 29 disposed in the user side unit 22 and an outdoor control section 39 disposed on the heat source side unit 21 . The indoor control section 29 and the outdoor control section 39 are connected to each other via a transmission line so that they can communicate with each other.

The indoor control unit 29 is a device that controls the operation of the user unit 22, and is configured by, for example, a microcomputer equipped with a processor such as a CPU, and a memory such as RAM and ROM. The indoor control unit 29 may be realized as hardware using LSI, ASIC, FPGA, or the like. The indoor control unit 29 performs a predetermined function by a processor executing a program installed in the memory. The user unit 22 includes an indoor fan current sensor 45 that detects the motor current value of the indoor fan 26 in addition to the indoor temperature sensor 27 described above. The detection values of each sensor provided in the user-side unit 22 are input to the indoor control section 29. The indoor control unit 29 controls the operation of the indoor expansion valve 24 and the indoor fan 26 based on the detected values of each sensor.

A remote controller 41 is connected to the indoor control unit 29, and allows the user to start/stop the user unit 22, change the set temperature, and the like. The remote control 41 is a device that serves as an operation unit for the air conditioner 10 by the user, and is placed in a target space to be air-conditioned by the air conditioner 10.

The remote control 41 includes a display section 42. The display section 42 is a section that displays the operating state, set temperature, etc. of the first air conditioner 11, and is configured with a liquid crystal panel. In the first air conditioner 11, the control unit 50 displays the currently executed operating mode on the display unit 42. In the first air conditioner 11, the display unit 42 can inform the user of the currently running operating mode.

The outdoor control section 39 is a device that controls the operation of the heat source side unit 21, and is configured by, for example, a microcomputer equipped with a processor such as a CPU, and a memory such as a RAM and a ROM. The outdoor control unit 39 may be realized as hardware using LSI, ASIC, FPGA, or the like. The outdoor control unit 39 performs a predetermined function by a processor executing a program installed in the memory. The outdoor control section 39 includes a processing section 39a in which a CPU or the like performs calculations, a storage section 39b in which ROM, RAM, etc. stores the calculation results of the processing section 39a, and an output section 39c that outputs the calculation results of the processing section 39a. have.

In addition to the above-mentioned refrigerant pressure sensor 35, refrigerant temperature sensor 36, and outside air temperature sensor 28, the heat source side unit 21 includes a compressor current sensor 43 that detects the current value of the compressor 30, and a motor current value of the outdoor fan 33. It has an outdoor fan current sensor 44 that detects. The detected values of each sensor provided in the heat source side unit 21 are input to the outdoor control section 39. The outdoor control unit 39 controls the operation of the air conditioner 10 by adjusting the functions performed by the outdoor expansion valve 34, the compressor 30, the outdoor fan 33, etc. based on the detected values of each sensor.

In the air conditioner 10, the control unit 50 uses the detected values of the refrigerant pressure sensor 35, the refrigerant temperature sensor 36, and the outside air temperature sensor 28 to determine the evaporation pressure and condensation pressure of the outdoor heat exchanger 31 and the indoor heat exchanger 25. , the degree of superheat, etc., and control the rotational speed of the compressor 30, the opening degree of the outdoor expansion valve 34, etc. so as to adjust these values, and also execute a determination process to be described later. Note that in this embodiment, the air conditioner 10 includes the refrigerant pressure sensor 35 and the refrigerant temperature sensor 36, but in the air conditioner 10, either the refrigerant pressure sensor 35 or the refrigerant temperature sensor 36 is omitted. It's okay. In this case, for example, the temperature of the refrigerant in each part of the refrigerant circuit 40 is calculated from the detected value of the refrigerant pressure sensor 35.

When the air conditioner 10 configured as described above performs cooling operation, the four-way switching valve 32 is maintained in the state shown by the solid line in FIG. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 30 flows into the outdoor heat exchanger 31 via the four-way switching valve 32, and is condensed and liquefied by exchanging heat with outdoor air by the operation of the outdoor fan 33. When the air conditioner 10 performs cooling operation, the outdoor heat exchanger 31 functions as a condenser. The liquefied refrigerant passes through the outdoor expansion valve 34 and flows into each user unit 22 . In the user unit 22, the refrigerant is reduced in pressure to a predetermined low pressure by the indoor expansion valve 24, and further exchanges heat with indoor air in the indoor heat exchanger 25 and evaporates. The indoor air cooled by the evaporation of the refrigerant is blown into the room by the indoor fan 26 to cool the room. The refrigerant evaporated in the indoor heat exchanger 25 returns to the heat source side unit 21 through the gas refrigerant pipe 40G, and is sucked into the compressor 30 through the four-way switching valve 32. When the air conditioner 10 performs cooling operation, the indoor heat exchanger 25 functions as an evaporator.

When the air conditioner 10 performs cooling operation, the outdoor control unit 39 sets the degree of subcooling of the refrigerant at the outlet of the outdoor heat exchanger 31 (first degree of supercooling SC1 to be described later) to a target value (target degree of supercooling). The rotation speed of the compressor 30 and the opening degree of the outdoor expansion valve 34 are adjusted so as to match the rotation speed of the compressor 30 and the opening degree of the outdoor expansion valve 34. When the air conditioner 10 performs cooling operation, the indoor control unit 29 makes the evaporation temperature of the indoor heat exchanger 25 (first evaporation temperature T1, which will be explained later) match a target value (also referred to as target evaporation temperature T0). Adjust the opening degree of the indoor expansion valve 24 as follows. The target supercooling degree SC0 and the target evaporation temperature T0 are calculated by the control unit 50, for example, based on the indoor set temperature and the actual indoor temperature in the first mode M1. The evaporation temperature may also be controlled by providing an expansion valve corresponding to the indoor expansion valve 24 on the heat source side unit 21 side and controlling the opening degrees of the expansion valve and the outdoor expansion valve 34 by the outdoor control section 39. good. In this case, the indoor expansion valve 24 may be omitted.

When the air conditioner 10 performs heating operation, the four-way switching valve 32 is maintained in the state shown by the broken line in FIG. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 30 passes through the four-way switching valve 32 and flows into the indoor heat exchanger 25 of each user unit 22 . In the indoor heat exchanger 25, the refrigerant exchanges heat with indoor air to condense and liquefy. When the air conditioner 10 performs heating operation, the indoor heat exchanger 25 functions as a condenser. Indoor air heated by the condensation of the refrigerant is blown into the room by the indoor fan 26, heating the room. The refrigerant liquefied in the indoor heat exchanger 25 returns to the heat source side unit 21 through the liquid refrigerant pipe 40L, is reduced in pressure to a predetermined low pressure by the outdoor expansion valve 34, and is further heat exchanged with outdoor air in the outdoor heat exchanger 31. and evaporate. The refrigerant evaporated in the outdoor heat exchanger 31 is sucked into the compressor 30 via the four-way switching valve 32. When the air conditioner 10 performs heating operation, the outdoor heat exchanger 31 functions as an evaporator.

The control unit 50 determines the degree of supercooling of the refrigerant at the outlet of the condenser (first degree of supercooling SC1 to be described later) based on the detected value of the refrigerant pressure sensor 35 or the refrigerant temperature sensor 36 during operation of the air conditioner 10. ) is calculated. The control unit 50 calculates the amount of refrigerant leakage from the difference between the calculated degree of subcooling and the target degree of subcooling SC0. In the air conditioner 10 of the present disclosure, the total amount of refrigerant filled in the refrigerant circuit 40 at the time of installation is used as a reference (100%), and if the amount of refrigerant leaks exceeds a set amount (for example, 30%), refrigerant leakage occurs. If the amount of refrigerant leakage does not exceed a set amount (for example, 30%), it is determined that there is no refrigerant leakage.

[About driving mode]
The air conditioner 10 is configured to be operable in a first mode M1, which is an operation mode for normal cooling operation, and a second mode M2, which is an operation mode suitable for determining refrigerant leakage. In the air conditioner 10, the control unit 50 controls the operation of the air conditioner 10 by switching the operation mode to the second mode M2 at a timing desired by the user or periodically. Note that the first mode M1 may be an operation mode in which normal cooling operation and heating operation are performed.

In the first mode M1, the control unit 50 controls the outdoor temperature so that the degree of subcooling SC1 (hereinafter also referred to as the first degree of subcooling SC1) of the refrigerant at the outlet of the outdoor heat exchanger 31 becomes the target degree of subcooling SC0. In addition to adjusting the opening degree of the expansion valve 34, the rotation speed of the compressor 30 and the indoor Adjust the opening degree of the expansion valve 24.

The second mode M2 is an operation mode suitable for determining whether there is a refrigerant leak in the refrigerant circuit 40. In the air conditioner 10, when operating in the second mode M2, the switching position of the four-way switching valve 32 is set to the position when performing the cooling operation in the first mode M1 (the position indicated by the solid line in FIG. 1). In the second mode M2, the control unit 50 determines that the degree of subcooling SC2 (hereinafter also referred to as second degree of subcooling SC2) of the refrigerant at the outlet of the outdoor heat exchanger 31 is equal to the first degree of subcooling in the first mode M1. The opening degree of the outdoor expansion valve 34 is adjusted so that the opening degree of the outdoor expansion valve 34 is lower than SC1, and the evaporation temperature T2 (hereinafter also referred to as second evaporation temperature T2) of the indoor heat exchanger 25 is set to the first evaporation temperature T2 in the first mode M1. The rotation speed of the compressor 30 and the opening degree of the indoor expansion valve 24 are adjusted so as to approach the evaporation temperature T1.

In the air conditioner 10, when the second mode M2 is executed, the second degree of supercooling SC2 of the refrigerant at the outlet of the outdoor heat exchanger 31 becomes lower than the first degree of supercooling SC1 in the first mode M1, and the accumulator Excess refrigerant accumulated in the accumulator 38 is discharged from the accumulator 38. In the air conditioner 10, when surplus refrigerant is accumulated in the accumulator 38, if refrigerant leaks from the refrigerant circuit 40, the surplus refrigerant in the accumulator 38 is replenished, so even if the amount of refrigerant leaked is sufficient to replace it with the surplus refrigerant. In other words, normal operating conditions are maintained. Therefore, in the air conditioner 10 having the accumulator 38, it is difficult to accurately determine whether there is a refrigerant leak.

In the air conditioner 10 of the present disclosure, by executing the second mode M2, the surplus refrigerant accumulated in the accumulator 38 can be expelled from the accumulator 38, and the determination process is executed in a state where there is no surplus refrigerant in the accumulator 38. can do. With this configuration, the air conditioner 10 can accurately determine the presence or absence of refrigerant leakage.

In the air conditioner 10, when the second mode M2 is executed and the second degree of supercooling SC2 of the refrigerant at the outlet of the outdoor heat exchanger 31 becomes lower than the first degree of supercooling SC1 in the first mode M1, the indoor heat is reduced. Since the evaporation temperature of the exchanger 25 decreases, if no action is taken, the temperature of the air supplied into the room (supply air temperature) decreases, potentially causing discomfort to the user.

In the air conditioner 10, when the second mode M2 is executed, the second degree of supercooling SC2 of the refrigerant at the outlet of the outdoor heat exchanger 31 is made lower than the first degree of supercooling SC1 in the first mode M1, and The opening degree of the indoor expansion valve 24 is adjusted so that the second evaporation temperature T2 of the indoor heat exchanger 25 approaches the first evaporation temperature T1 in the first mode M1. Therefore, in the air conditioner 10, during execution of the second mode M2, it is possible to suppress a decrease in the second evaporation temperature T2 of the indoor heat exchanger 25 and suppress a decrease in the supply air temperature. The possibility of causing discomfort to other users can be reduced.

In the air conditioner 10, it is preferable that a first set value X1 and a second set value X2, which will be described below, are set in the control unit 50. The first set value X1 is, for example, the time to start driving in the second mode M2. Note that the first set value X1 is a value (for example, 24 hours) that defines the period (interval) after the execution of the operation in the second mode M2 until the next execution of the operation in the second mode M2. Good too. When the first set value X1 is set in the control unit 50, the control unit 50 switches the air conditioner 10 to the second mode M2 at a timing desired by the user or periodically according to the first set value X1. Let it drive.

The second set value X2 is, for example, the time at which the operation in the second mode M2 ends. Note that the second set value X2 may be a value (for example, one hour) that defines a period (interval) from the start to the end of the operation in the second mode M2. When the second set value X2 is set in the control unit 50, the control unit 50 ends the operation of the air conditioner 10 in the second mode M2 at a timing desired by the user according to the second set value X2.

It is preferable that the air conditioner 10 is configured such that the first set value X1 and the second set value X2 stored in the control unit 50 can be changed by the user. The air conditioner 10 is configured such that a user can change the first set value X1 and the second set value X2 by operating the remote control 41. In the air conditioner 10 having such a configuration, the operation mode of the air conditioner 10 is switched to the second mode M2 at a timing desired by the user, and the operation mode of the air conditioner 10 is switched to the second mode M2 at a timing desired by the user. This makes it possible to terminate the operation of the vehicle.

[About the determination process performed by the control unit]
FIG. 4 is a flow diagram showing the determination process. In the air conditioner 10, it is preferable that the control unit 50 executes the determination process described above in accordance with the flow shown in FIG.

In the air conditioner 10, when the operation is started, the control unit 50 starts a process for determining the presence or absence of refrigerant leakage in accordance with the flow shown in FIG. In the air conditioner 10, when the determination process is started, the control unit 50 executes step (S01).

In step (S01), the control unit 50 makes a determination regarding the timing to start driving in the second mode M2. In step (S01), the control unit 50 determines whether the current time corresponds to the timing defined by the first set value X1. When the control unit 50 determines that the current time corresponds to the timing defined by the first set value X1, it executes step (S02). If the control unit 50 determines that the current time does not correspond to the timing specified by the first set value X1, it repeatedly executes the process of step (S01) until it determines that the current time does not correspond to the timing specified by the first set value X1.

In step (S02), the control unit 50 switches the operation mode of the air conditioner 10 to the second mode M2. When the switching to the second mode M2 is completed, the control unit 50 next executes step (S03).

In step (S03), the control unit 50 determines the presence or absence of refrigerant leakage based on the measured values of each sensor 35 and 36 for the air conditioner 10 executing the second mode M2, and then in step (S04) Execute.

In step (S04), the control unit 50 makes a determination regarding the timing to end the operation in the second mode M2. In step (S04), the control unit 50 determines whether the current time corresponds to the timing defined by the second set value X2. When the control unit 50 determines that the current time corresponds to the timing defined by the second set value X2, it executes step (S05). If the control unit 50 determines that the current time does not correspond to the timing specified by the second set value X2, it continues the process of step (S03) (determining whether there is a refrigerant leak) until it determines that the current time does not correspond to the timing specified by the second set value X2.

In the air conditioner 10, the presence or absence of refrigerant leakage can be determined more accurately if the presence or absence of refrigerant leakage is determined based on more operating data over time, but in this case, the second mode M2 This increases the possibility that the driver will have to drive for a long time, causing discomfort to the user inside the vehicle. On the other hand, if the operation in the second mode M2 is made shorter, there is a lower possibility of causing discomfort to the user indoors, but in this case, it is difficult to determine whether there is a refrigerant leak based on a small amount of operation data. Therefore, the accuracy of determining whether or not there is a refrigerant leak decreases. In this way, in the air conditioner 10, there are advantages and disadvantages when the time taken to determine refrigerant leakage (the operating time in the second mode M2) is lengthened and when it is shortened. For this reason, the air conditioner 10 is configured so that the user can select the time required to determine refrigerant leakage (the operating time in the second mode M2). Specifically, in the air conditioner 10, the user can change the first set value X1 and the second set value X2 by operating the remote controller 41. With this configuration, the air conditioner 10 can perform determination processing that is tailored to the state of the air conditioner 10 and the user's preferences.

In step (S05), the control unit 50 switches the operation mode of the air conditioner 10 from the second mode M2 to the first mode M1. When the switching to the first mode M1 is completed, the control unit 50 ends the series of determination processing.

Note that in the air conditioner 10 of the present disclosure, a case is illustrated in which the outdoor control section 39 of the control section 50 executes the determination process, but the indoor control section 29 is configured to execute the determination process. Good too.

Note that in the air conditioner 10, the first set value X1 and the second set value X2 may not be set in the control unit 50. In this case, step (S01) and step (S04) of the flow shown in FIG. 4 are omitted. The air conditioner 10 in which the settings of the first set value X1 and the second set value X2 are omitted is provided with a switch that instructs the start of the determination process, for example, and when the user operates the switch, the control unit 50 It may be configured such that the air conditioner 10 is operated by switching to the second mode M2 only for a preset time, and the presence or absence of refrigerant leakage is determined during that time.

Note that the method for determining whether there is a refrigerant leak as described above is particularly effective for the air conditioner 10 that has the accumulator 38, but the method for determining whether there is a refrigerant leak of the present disclosure is effective for the air conditioner 10 that has the accumulator 38. The same may be applied to the harmonizing device 10.

[About the air conditioner according to the second embodiment]
FIG. 5 is a schematic configuration diagram of an air conditioner according to the second embodiment. FIG. 6 is a block diagram of an air conditioner according to the second embodiment. The air conditioner 10 of the present disclosure may have the configuration shown in FIG. 5. The second air conditioner 12 shown in FIG. 5 is a second embodiment of the air conditioner 10 of the present disclosure. As shown in FIGS. 5 and 6, the second air conditioner 12 differs from the first air conditioner 11 in the configuration of the control section 50. In the following description, the control unit 50 included in the second air conditioner 12 will be referred to as a second control unit 52.

As shown in FIGS. 5 and 6, the second air conditioner 12 differs from the first air conditioner 11 in that it includes a monitoring device 60. The monitoring device 60 is installed, for example, in a central monitoring room of a building. The monitoring device 60 monitors (manages) the operations of the heat source side unit 21 and the usage side unit 22.

The monitoring device 60 includes a control section 61. The control unit 61 is composed of, for example, a microcomputer including a processor such as a CPU, and a memory such as a RAM and a ROM. The control unit 61 may be realized as hardware using LSI, ASIC, FPGA, or the like. The control unit 61 performs a predetermined function by a processor executing a program installed in the memory. The control unit 61 includes a processing unit 61a in which a CPU or the like performs calculations, a storage unit 61b in which ROM, RAM, etc. stores the calculation results of the processing unit 61a, and an output unit 61c that outputs the calculation results of the processing unit 61a. are doing.

The second air conditioner 12 differs from the first air conditioner 11 in that it further includes a management server 70. Note that the second air conditioner 12 may omit the management server 70.

The management server 70 is provided in a remote location away from the building where the air conditioner 10 is installed. The management server 70 is configured by, for example, a personal computer including a control unit 71 having a calculation unit such as a CPU and a storage unit such as a ROM or RAM. The control section 71 includes a processing section 71a in which a CPU or the like performs calculations, a storage section 71b in which ROM, RAM, etc. stores the calculation results of the processing section 71a, and an output section 71c that outputs the calculation results of the processing section 71a. are doing. The monitoring device 60 and the management server 70 are communicably connected via a network 80 such as the Internet.

As shown in FIGS. 5 and 6, the second control section 52 includes an indoor control section 29, an outdoor control section 39, a control section 61 of the monitoring device 60, and a control section 71 of the management server 70. The indoor control section 29 and the outdoor control section 39 are connected to a monitoring device 60 via a transmission line. The indoor control section 29, the outdoor control section 39, and the control section 61 are connected to a management server 70 via a network 80. In the second air conditioner 12 having such a configuration, the operation of the second air conditioner 12 can be controlled by the control section 61 included in the second control section 52. In the second air conditioner 12, the control unit 61 may control the operation of the second air conditioner 12 in the second mode M2 suitable for the determination process, and may also execute the determination process described above.

When the control unit 61 executes the determination process, the processing unit 61a executes the determination process based on the first setting value X1 and the second setting value X2 stored in the storage unit 61b. The determination result of the presence or absence of refrigerant leakage performed by the processing unit 61a is stored in the storage unit 61b. In the control section 61, the output section 61c causes the display section 42 to display the determination result stored in the storage section 61b. The second air conditioner 12 is configured such that the first set value X1 and the second set value X2 stored in the storage section 61b can be changed by the user's operation of the remote control 41.

Alternatively, in the second air conditioner 12 having the management server 70, the operation of the second air conditioner 12 can be controlled by the control section 71 included in the second control section 52. In the second air conditioner 12, the control unit 71 may control the operation of the second air conditioner 12 in the second mode M2 suitable for the determination process, and may also execute the determination process described above.

When the control unit 71 executes the determination process, the processing unit 71a executes the determination process based on the first set value X1 and the second set value X2 stored in the storage unit 71b. The determination result of the presence or absence of refrigerant leakage performed by the processing unit 71a is stored in the storage unit 71b. In the control section 71, the output section 71c causes the display section 42 to display the determination result stored in the storage section 71b. The second air conditioner 12 is configured such that the first set value X1 and the second set value X2 stored in the storage section 71b can be changed by the user's operation of the remote control 41.

[Operations and effects of embodiment]
(1) The air conditioner 10 of the above embodiment includes a compressor 30, an outdoor heat exchanger 31, an indoor heat exchanger 25, an indoor expansion valve 24, and an outdoor expansion valve 34 connected by refrigerant pipes 40G and 40L. A refrigerant circuit 40, a refrigerant pressure sensor 35 and a refrigerant temperature sensor 36 that measure the temperature or pressure of refrigerant at a predetermined location in the refrigerant circuit 40, and indoor expansion valves 24 and 36 based on the measured values of each sensor 35, 36. It includes a control unit 50 that controls the refrigerant circuit 40 by adjusting the opening degree of the outdoor expansion valve 34 and the rotation speed of the compressor 30, and executes a process of determining whether or not there is refrigerant leakage in the refrigerant circuit 40. In the air conditioner 10, the control unit 50 can operate the air conditioner 10 in a first mode M1 when performing normal cooling operation and in a second mode M2 when performing a determination process. In the air conditioner 10, the control unit 50 sets the second degree of subcooling SC2 of the refrigerant at the outlet of the outdoor heat exchanger 31 in the second mode M2 to the second degree of subcooling SC2 of the refrigerant at the outlet of the outdoor heat exchanger 31 in the first mode M1. 1 subcooling degree SC1, and the second evaporation temperature T2 of the refrigerant in the indoor heat exchanger 25 in the second mode M2 is lowered to the first evaporation temperature T1 of the indoor heat exchanger 25 in the first mode M1. get closer to

According to such an air conditioner 10, when the operation in the second mode M2 is performed, it is possible to suppress the temperature of the air that has passed through the evaporator from decreasing, so that the air is supplied. The comfort level in the room is not impaired, and even if there is a user in the room, driving in the second mode M2 can be performed. As a result, it is possible to reduce restrictions on the timing of determining the presence or absence of refrigerant leakage in the air conditioner 10 in a state suitable for determining refrigerant leakage (in other words, operated in the second mode M2).

(2) The air conditioner 10 of the above embodiment has an outdoor expansion valve 34 that adjusts the pressure of the refrigerant at the outlet of the outdoor heat exchanger 31 and an expansion valve that adjusts the pressure of the refrigerant at the inlet of the indoor heat exchanger 25. and an indoor expansion valve 24. In the air conditioner 10, the control unit 50 controls the outdoor expansion valve 34 to lower the second degree of supercooling SC2 compared to the first degree of supercooling SC1, and also controls the opening degree of the indoor expansion valve 24 and the compressor. 30 to bring the second evaporation temperature T2 closer to the first evaporation temperature T1. In this case, it is possible to reduce restrictions on the timing of determining whether there is a refrigerant leak in the air conditioner 10 in a state suitable for refrigerant leak determination (in other words, operating in the second mode M2).

(3) In the air conditioner 10 of the above embodiment, the refrigerant circuit 40 includes an accumulator 38 that is a tank that stores surplus refrigerant in the refrigerant circuit 40. In this case, for the air conditioner 10 having the accumulator 38 that stores surplus refrigerant in the refrigerant circuit 40, restrictions on the timing of determining the presence or absence of refrigerant leakage in a state suitable for determining refrigerant leakage can be reduced.

(4) In the air conditioner 10 of the above embodiment, the control unit 50 periodically operates the air conditioner 10 in the second mode M2, and makes a determination while the air conditioner 10 is operating in the second mode M2. Execute processing. In this case, the presence or absence of refrigerant leakage of the air conditioner 10 can be periodically determined with high accuracy.

(5) The air conditioner 10 of the above embodiment further includes a display unit 42 that displays information regarding the operation mode of the air conditioner 10. In this case, the display unit 42 can inform the user that the air conditioner 10 is being operated in the second mode M2.

(6) The air conditioner 10 of the above embodiment has the first setting value X1 regarding the timing of starting the operation of the air conditioner 10 in the second mode M2 and the end of the operation of the air conditioner 10 in the second mode M2. The device further includes a remote controller 41 capable of setting a second setting value X2 regarding timing. In the air conditioner 10, the control unit 50 controls the air conditioner 10 based on the set first set value X1 and second set value X2. In this case, the user can select the timing to execute the second mode M2. Further, the user can select the period for executing the second mode M2, and thereby the user can select the accuracy of determining whether there is a refrigerant leak in the air conditioner 10.

(7) The method for determining refrigerant leakage in the above embodiment includes the compressor 30, the outdoor heat exchanger 31, the indoor heat exchanger 25, the indoor expansion valve 24, and the outdoor expansion valve 34 connected by the refrigerant pipes 40G and 40L. a refrigerant circuit 40 including a refrigerant circuit 40, a refrigerant pressure sensor 35 and a refrigerant temperature sensor 36 that measure the temperature or pressure of the refrigerant at a predetermined location in the refrigerant circuit 40, and an indoor expansion valve 24 based on the measured values of each sensor 35, 36. and a control unit 50 that controls the refrigerant circuit 40 by adjusting the opening degree of the outdoor expansion valve 34 and the rotation speed of the compressor 30, and also executes a process of determining whether there is a refrigerant leak in the refrigerant circuit 40. This is a method for determining refrigerant leakage in the harmonizing device 10. The control unit 50 can operate the air conditioner 10 in a first mode M1 when performing normal cooling operation and a second mode M2 when performing a determination process. In the method for determining refrigerant leakage of the present disclosure, the control unit 50 sets the second degree of subcooling SC2 of the refrigerant at the outlet of the outdoor heat exchanger 31 in the second mode M2 to the second degree of subcooling SC2 at the outlet of the outdoor heat exchanger 31 in the first mode M1. The second evaporation temperature T2 of the refrigerant in the indoor heat exchanger 25 in the second mode M2 is lowered compared to the first subcooling degree SC1 at the outlet of the indoor heat exchanger 25 in the first mode M1. 1. Bring the temperature close to evaporation temperature T1.

According to the refrigerant leak determination method of the present disclosure, even when a user is indoors, operation in the second mode M2 can be performed, and the presence or absence of refrigerant leak can be determined in a state suitable for determining refrigerant leak. Timing constraints can be reduced.

Note that the present disclosure is not limited to the above examples, but is indicated by the scope of the claims, and is intended to include all changes within the meaning and scope equivalent to the scope of the claims.

10: Air conditioner (refrigeration cycle device)
21: Heat source side unit 22: User side unit 23: Connection pipe 24: Indoor expansion valve (valve, second valve)
25: Indoor heat exchanger (evaporator)
30: Compressor 31: Outdoor heat exchanger (condenser)
34: Outdoor expansion valve (valve, first valve)
35: Refrigerant pressure sensor (sensor)
36: Refrigerant temperature sensor (sensor)
38: Accumulator (tank)
40: Refrigerant circuit 40L: Liquid refrigerant piping (refrigerant piping)
40G: Gas refrigerant piping (refrigerant piping)
41: Remote control (operation unit)
42: Display section 50: Control section M1: First mode M2: Second mode X1: First set value X2: Second set value SC1: First degree of supercooling SC2: Second degree of supercooling T1: First evaporation temperature T2: Second evaporation temperature

Claims (7)

A refrigeration cycle device (10),
A refrigerant circuit (40) including a compressor (30), a condenser (31), an evaporator (25), and valves (24, 34) connected by refrigerant piping (40G, 40L);
a sensor (35, 36) that measures the temperature or pressure of the refrigerant at a predetermined location in the refrigerant circuit (40);
Based on the measured values of the sensors (35, 36), the opening degrees of the valves (24, 34) and the rotation speed of the compressor (30) are adjusted to control the refrigerant circuit (40), and the A control unit (50) that executes a process of determining whether there is a refrigerant leak in the refrigerant circuit (40),
The control unit (50) can operate the refrigeration cycle device (10) in a first mode (M1) when performing normal cooling operation and in a second mode (M2) when performing the determination process. and
The control unit (50) controls the second degree of subcooling (SC2) of the refrigerant at the outlet of the condenser (31) in the second mode (M2) to the degree of subcooling (SC2) of the refrigerant at the outlet of the condenser (31) in the second mode (M2), (31) compared to the first degree of subcooling (SC1) of the refrigerant at the outlet, and the second evaporation temperature (T2) of the refrigerant in the evaporator (25) in the second mode (M2), A refrigeration cycle device (10) that approaches a first evaporation temperature (T1) of the evaporator (25) in the first mode (M1). The valves include a first valve (34) that adjusts the pressure of the refrigerant at the outlet of the condenser (31), and a second valve (24) that adjusts the pressure of the refrigerant at the inlet of the evaporator (25); including;
The control unit (50) controls the first valve (34) to lower the second degree of supercooling (SC2) compared to the first degree of supercooling (SC1), and The refrigeration according to claim 1, wherein the second evaporation temperature (T2) is brought close to the first evaporation temperature (T1) by controlling the opening degree of the valve (24) and the rotation speed of the compressor (30). Cycle device (10). The refrigeration cycle device (10) according to claim 1 or 2, wherein the refrigerant circuit (40) has a tank (38) that stores surplus refrigerant in the refrigerant circuit (40). The control unit (50) periodically operates the refrigeration cycle device (10) in the second mode (M2), and while the refrigeration cycle device (10) is operating in the second mode (M2). The refrigeration cycle device (10) according to any one of claims 1 to 3, which executes the determination process. The refrigeration cycle device (10) according to any one of claims 1 to 4, further comprising a display section (42) that displays information regarding the operation mode of the refrigeration cycle device (10). A first setting value (X1) regarding the timing of starting the operation of the refrigeration cycle device (10) in the second mode (M2) and ending the operation of the refrigeration cycle device (10) in the second mode (M2). further comprising an operation unit (41) capable of setting a second setting value (X2) regarding the timing of
Any one of claims 1 to 5, wherein the control unit (50) controls the refrigeration cycle device (10) based on the first set value (X1) and the second set value (X2) that have been set. The refrigeration cycle device (10) described in section 1. A refrigerant circuit (40) including a compressor (30), a condenser (31), an evaporator (25), and valves (24, 34) connected by refrigerant piping (40G, 40L);
a sensor (35, 36) that measures the temperature or pressure of the refrigerant at a predetermined location in the refrigerant circuit (40);
Based on the measured values of the sensors (35, 36), the opening degrees of the valves (24, 34) and the rotation speed of the compressor (30) are adjusted to control the refrigerant circuit (40), and the A method for determining refrigerant leakage in a refrigeration cycle device (10), comprising: a control unit (50) that executes a process for determining the presence or absence of refrigerant leakage in a refrigerant circuit (40),
The control unit (50) can operate the refrigeration cycle device (10) in a first mode (M1) when performing normal cooling operation and a second mode (M2) when performing the determination process. The second degree of supercooling (SC2) of the refrigerant at the outlet of the condenser (31) in the second mode (M2) is set to The second evaporation temperature (T2) of the refrigerant in the evaporator (25) in the second mode (M2) is lowered compared to the first degree of subcooling (SC1) in the first mode (M1). A method for determining refrigerant leakage that approaches the first evaporation temperature (T1) of the evaporator (25).

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