JP7154388B2 - Outdoor unit and refrigeration cycle device provided with the same - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an outdoor unit and a refrigeration cycle device including the same.

Japanese Patent Laying-Open No. 2012-132639 (Patent Document 1) discloses a refrigeration cycle device. An outdoor unit of this refrigeration cycle apparatus includes a compressor, an oil separator, a condenser, a receiver, a subcooling heat exchanger, and an accumulator. The indoor unit includes an expansion valve and an evaporator. In this refrigeration cycle apparatus, the suitability of the amount of refrigerant charged in the refrigerant circuit is determined based on the temperature efficiency of the subcooling heat exchanger. The temperature efficiency is the degree of subcooling of the refrigerant at the outlet of the subcooling heat exchanger divided by the maximum temperature difference of the subcooling heat exchanger. According to this refrigeration cycle device, it is possible to determine the shortage of refrigerant circulating in the refrigerant circuit.

JP 2012-132639 A

When it is determined that the refrigerant circulating in the refrigerant circuit is insufficient, there are various causes other than refrigerant leakage. It is not possible to notify the factor determined to be insufficient. As a result, it is not possible for the on-site worker to respond to the cause of the shortage of the refrigerant circulating in the refrigerant circuit.

The present disclosure has been made to solve such problems, and an object of the present disclosure is to be able to determine the shortage of refrigerant circulating in a refrigerant circuit and to notify the cause of the shortage of refrigerant. An object of the present invention is to provide an outdoor unit and a refrigeration cycle device including the same.

An outdoor unit of the present disclosure is an outdoor unit that is connected to an indoor unit to form a refrigeration cycle device, and includes a compressor that compresses a refrigerant and a condenser that condenses the refrigerant output from the compressor. The compressor and condenser form a refrigerant circuit that circulates the refrigerant together with an expansion mechanism and an evaporator included in the indoor unit. The outdoor unit further determines whether or not the refrigerant circulating in the refrigerant circuit is insufficient, and when it is determined that the refrigerant is insufficient, the liquid bag A control device is provided for notifying one of operation, operation with a high refrigerant evaporation temperature, and refrigerant leakage from the refrigerant circuit.

According to the outdoor unit of the present disclosure and the refrigeration cycle device including the same, it is possible to determine the shortage of the refrigerant circulating in the refrigerant circuit and to notify the cause of the shortage of the refrigerant.

1 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 1. FIG. FIG. 4 is a diagram conceptually showing the state of coolant around the heater in a normal state when there is no shortage of coolant; FIG. 5 is a diagram showing an example of change in coolant temperature caused by a heater during normal operation; FIG. 4 is a diagram conceptually showing the state of coolant around a heater when there is a shortage of coolant; FIG. 4 is a diagram showing an example of change in coolant temperature caused by a heater when there is a shortage of coolant; 4 is a flow chart showing an example of a refrigerant shortage determination processing procedure executed by a control device in Embodiment 1. FIG. It is a figure which shows roughly the structure of an outdoor unit. FIG. 2 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 2; FIG. 11 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by a control device 100A in Embodiment 2. FIG. FIG. 11 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 3; FIG. 13 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by a control device 100C in Embodiment 3. FIG. FIG. 11 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 4; FIG. 14 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by a control device 100D in Embodiment 4. FIG. FIG. 11 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 5; FIG. 12 is a diagram for explaining a refrigerant shortage determination process performed by a control device according to Embodiment 5; FIG. 14 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by a control device 100B in Embodiment 5. FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. A plurality of embodiments will be described below, but appropriate combinations of the configurations described in the respective embodiments have been planned since the filing of the application. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

Embodiment 1.
FIG. 1 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 1. FIG. FIG. 1 functionally shows the connection relationship and arrangement configuration of each device in the refrigeration cycle apparatus, and does not necessarily show the arrangement in a physical space.

Referring to FIG. 1 , refrigeration cycle device 1 includes an outdoor unit 2 and an indoor unit 3 . The outdoor unit 2 includes a compressor 10, a condenser 20, a fan 22, a liquid reservoir 30, a supercooling heat exchanger 40, a fan 42, a sight glass 45, and pipes 80 to 83, 85. include. Outdoor unit 2 further includes pipes 86 and 87 , a refrigerant amount detector 70 , a suction pressure sensor 90 , a discharge pressure sensor 92 , a control device 100 and a display device 150 . Indoor unit 3 includes an expansion mechanism 50 , an evaporator 60 , a fan 62 , and piping 84 . The indoor unit 3 is connected to the outdoor unit 2 through pipes 83 and 85 .

A pipe 80 connects the discharge port of the compressor 10 and the condenser 20 . A pipe 81 connects the condenser 20 and the liquid reservoir 30 . A pipe 82 connects the liquid reservoir 30 and the subcooling heat exchanger 40 . A pipe 83 connects the subcooling heat exchanger 40 and the expansion mechanism 50 . A pipe 84 connects the expansion mechanism 50 and the evaporator 60 . A pipe 85 connects the evaporator 60 and the suction port of the compressor 10 . A pipe 86 connects the pipe 82 and the refrigerant amount detector 70 . A pipe 87 connects the refrigerant amount detector 70 and the pipe 85 .

Compressor 10 compresses the refrigerant sucked from pipe 85 and outputs the compressed refrigerant to pipe 80 . Compressor 10 is configured to adjust the rotation speed according to a control signal from control device 100 . By adjusting the rotation speed of the compressor 10, the circulation amount of the refrigerant is adjusted, and the capacity of the refrigeration cycle device 1 can be adjusted. Various types can be adopted for the compressor 10, for example, a scroll type, a rotary type, a screw type, and the like can be adopted.

The condenser 20 condenses the refrigerant output from the compressor 10 to the pipe 80 and outputs the condensed refrigerant to the pipe 81 . Condenser 20 is configured such that the high-temperature, high-pressure gas refrigerant output from compressor 10 exchanges heat (radiates heat) with the outside air. This heat exchange causes the refrigerant to condense and change to a liquid phase. The fan 22 supplies outside air to the condenser 20 with which the refrigerant exchanges heat in the condenser 20 . By adjusting the rotational speed of the fan 22, the pressure of the refrigerant on the discharge side of the compressor 10 (high-pressure side pressure) can be adjusted.

The liquid reservoir 30 stores the high-pressure liquid refrigerant condensed by the condenser 20 . The supercooling heat exchanger 40 is configured such that the liquid refrigerant output from the liquid reservoir 30 to the pipe 82 further exchanges heat (radiates heat) with the outside air. The refrigerant becomes supercooled liquid refrigerant by passing through the supercooling heat exchanger 40 . The fan 42 supplies the supercooling heat exchanger 40 with outside air with which the refrigerant exchanges heat in the supercooling heat exchanger 40 . The sight glass 45 is a window for visually confirming air bubbles (flash gas) in the refrigerant flowing through the pipe 83 .

The expansion mechanism 50 decompresses the refrigerant output from the supercooling heat exchanger 40 to the pipe 83 and outputs the reduced pressure to the pipe 84 . An expansion valve, for example, can be used as the expansion mechanism 50 . When the opening degree of the expansion valve is changed in the closing direction, the refrigerant pressure on the discharge side of the expansion valve decreases and the dryness of the refrigerant increases. When the opening degree of the expansion valve is changed in the opening direction, the pressure of the refrigerant on the discharge side of the expansion valve increases and the dryness of the refrigerant decreases. A capillary tube may be used as the expansion mechanism 50 instead of the expansion valve.

Evaporator 60 evaporates the refrigerant output from expansion mechanism 50 to pipe 84 and outputs the same to pipe 85 . The evaporator 60 is configured such that the refrigerant decompressed by the expansion mechanism 50 exchanges heat (absorbs heat) with the air inside the indoor unit 3 . The refrigerant passes through the evaporator 60 and evaporates into superheated vapor. Fan 62 supplies outside air to evaporator 60 with which the refrigerant exchanges heat in evaporator 60 .

The compressor 10, the pipe 80 , the condenser 20, the pipe 81, the liquid reservoir 30, the pipe 82, the subcooling heat exchanger 40, the pipe 83, the expansion mechanism 50, the pipe 84, the evaporator 60, and the pipe 85 contain refrigerant. A circulating refrigerant circuit 5 is formed.

The refrigerant amount detector 70 is provided between a pipe 86 branching from the pipe 82 and a pipe 87 connected to the pipe 85 . The pipe 86 , the refrigerant amount detector 70 , and the pipe 87 constitute a “bypass circuit” that returns part of the refrigerant on the discharge side of the condenser 20 to the compressor 10 without passing through the indoor unit 3 .

Refrigerant amount detection unit 70 includes a capillary tube (decompression device) 71 , a heater 72 , and temperature sensors 73 and 74 . The capillary tube 71 is connected between the pipes 86 and 87 and reduces the pressure of the refrigerant flowing through the bypass circuit. The capillary tube 71 is designed so that when the liquid refrigerant is supplied from the pipe 86, even if the refrigerant passing through the capillary tube 71 is heated by the heater 72, it does not become a single gas phase but a two-phase gas-liquid phase. It is appropriately designed in consideration of the amount of heating. An expansion valve may be used instead of the capillary tube 71 .

A heater 72 and temperature sensors 73 and 74 are provided in a pipe 87 . The heater 72 heats the coolant that has passed through the capillary tube 71 . The refrigerant is heated by the heater 72 to increase its enthalpy. As described above, the heating amount of the heater 72 is determined according to the specifications of the capillary tube 71 so that the refrigerant passing through the capillary tube 71 is heated by the heater 72 and does not become a single gas phase but a gas-liquid two-phase refrigerant. set. The heater 72 may heat the refrigerant from the outside of the pipe 87, or may be installed inside the pipe 87 in order to more reliably transfer heat from the heater 72 to the refrigerant. When the refrigerating cycle device 1 is ON, the heater 72 may always be ON. Alternatively, the heater 72 may be turned ON only during the refrigerant shortage determination process. Alternatively, the heater 72 may be turned ON only when the compressor 10 is activated. In the first embodiment, it is assumed that the heater 72 is ON only during the refrigerant shortage determination process.

Refrigerant amount detection unit 70 further includes an electromagnetic valve 79 . The solenoid valve 79 is provided in the piping 86 upstream of the capillary tube 71 and opens and closes according to instructions from the control device 100 . When the electromagnetic valve 79 is opened, the refrigerant flows through the capillary tube 71 and the pipe 87, making it possible to detect the lack of refrigerant. When the electromagnetic valve 79 is closed, the flow of refrigerant to the capillary tube 71 and the pipe 87 is cut off, so refrigerant shortage detection cannot be executed.

When the refrigerating cycle device 1 is ON, the electromagnetic valve 79 may be kept ON all the time. Alternatively, the solenoid valve 79 may be turned ON only during the refrigerant shortage determination process. In Embodiment 1, description will be given on the assumption that the solenoid valve 79 is ON only during the refrigerant shortage determination process.

Although the solenoid valve 79 is provided in the pipe 86 in FIG. 1 , the solenoid valve 79 may be provided in the pipe 87 downstream of the capillary tube 71 . However, it is preferable to provide the solenoid valve 79 in the pipe 86 because the amount of the liquid refrigerant that settles in the bypass circuit during normal operation can be reduced by arranging the solenoid valve 79 upstream in the bypass circuit. Furthermore, it is more preferable to provide the solenoid valve 79 as close as possible to the branching portion where the pipe 86 branches off from the pipe 82 .

The temperature sensor 73 detects the refrigerant temperature before the refrigerant is heated by the heater 72 , that is, the temperature T<b>1 of the refrigerant between the capillary tube 71 and the heater 72 , and outputs the detected value to the control device 100 . On the other hand, the temperature sensor 74 detects the refrigerant temperature after the refrigerant is heated by the heater 72, that is, the temperature T2 of the refrigerant downstream of the heater 72 and before joining the pipe 85, and outputs the detected value to the control device 100. do. The temperature sensors 73 and 74 may be installed outside the pipe 87, or may be installed inside the pipe 87 to more reliably detect the temperature of the refrigerant. The principle and method of refrigerant shortage determination by the refrigerant amount detection unit 70 will be described later in detail.

Suction pressure sensor 90 detects a refrigerant suction pressure LP in pipe 85 and outputs the detected value to control device 100 . That is, the suction pressure sensor 90 detects the refrigerant pressure (low pressure side pressure) LP on the suction side of the compressor 10 . Discharge pressure sensor 92 detects the discharge pressure HP of the refrigerant in pipe 80 and outputs the detected value to control device 100 . That is, the discharge pressure sensor 92 detects the refrigerant pressure (high pressure side pressure) HP on the discharge side of the compressor 10 .

The intake temperature sensor 302 is arranged around the intake of the compressor 10 . A suction temperature sensor 302 detects the suction temperature Ts of the refrigerant to the compressor 10 .

The evaporation temperature sensor 303 detects the temperature of the refrigerant flowing through the evaporator 60 as the evaporation temperature Te of the refrigerant.

The control device 100 includes a CPU (Central Processing Unit) 102, a memory 104 (ROM (Read Only Memory) and RAM (Random Access Memory)), an input/output buffer (not shown) for inputting and outputting various signals, and the like. Consists of The CPU 102 expands a program stored in the ROM into the RAM or the like and executes it. The program stored in the ROM is a program in which processing procedures of the control device 100 are described. The control device 100 controls each device in the outdoor unit 2 according to these programs. This control is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible.

The display device 150 displays information such as the state of the refrigeration cycle apparatus 1 sent from the control device 100 in order to notify the user or operator.

<Description of refrigerant shortage determination>
A method for judging the shortage of refrigerant using the refrigerant amount detection unit 70 will be described below. Insufficient refrigerant occurs when the initial amount of refrigerant charged into the refrigerant circuit is insufficient, or refrigerant leakage occurs after the start of use.

FIG. 2 is a diagram conceptually showing the state of the coolant around the heater 72 in a normal state when there is no shortage of coolant. Note that, hereinafter, the time when there is no shortage of refrigerant and the amount of refrigerant is within an appropriate range may be simply referred to as "normal time".

Referring to FIG. 1 as well as FIG. 2, when the amount of refrigerant is normal and the amount of refrigerant is appropriate, the refrigerant at the outlet of the condenser 20 is in a substantially liquid phase, and the liquid refrigerant is accumulated in the liquid reservoir 30 . As a result, the liquid refrigerant flows through the pipe 86, and the refrigerant that has passed through the capillary tube 71 has a large amount of liquid components. The refrigerant that has passed through the capillary tube 71 is heated by the heater 72 to increase its dryness.

FIG. 3 is a diagram showing an example of changes in coolant temperature caused by the heater 72 during normal operation. In FIG. 3, the horizontal axis indicates the position in the extending direction of the pipe 87, and P1 and P2 indicate the positions where the temperature sensors 73 and 74 are installed, respectively. The vertical axis indicates the coolant temperature at each position of the pipe 87 . Note that FIG. 3 shows a case where the refrigerant is an azeotropic refrigerant (a refrigerant that does not have a temperature gradient, such as R410a).

Referring to FIG. 3, normally, the refrigerant that has passed through the capillary tube 71 has a large amount of liquid components. It is used for the latent heat change of the refrigerant.). Therefore, the temperature T2 of the refrigerant after heating the refrigerant by the heater 72 is substantially the same as the temperature T1 of the refrigerant before heating the refrigerant by the heater 72 .

Although not shown, if the refrigerant is a non-azeotropic refrigerant (refrigerant having a temperature gradient, such as R407a, R448a, R449a, R463a, etc.), heating by the heater 72 slightly increases the temperature of the refrigerant. (At most about 10 degrees).

FIG. 4 is a diagram conceptually showing the state of the coolant around the heater 72 when the coolant is insufficient. Referring to FIG. 1 together with FIG. 4, when the refrigerant is insufficient, the refrigerant at the outlet of the condenser 20 is in a two-phase gas-liquid state. A small amount. As a result, gas-liquid two-phase refrigerant flows through the pipe 86, and the refrigerant that has passed through the capillary tube 71 is in a state in which there are more gas components than in the normal state. Therefore, the coolant that has passed through the capillary tube 71 is heated by the heater 72 to evaporate and its temperature (degree of superheat) rises.

FIG. 5 is a diagram showing an example of a coolant temperature change by the heater 72 when the coolant is insufficient. In FIG. 5 as well, the horizontal axis indicates the position in the extending direction of the pipe 87, and P1 and P2 indicate the positions where the temperature sensors 73 and 74 are installed, respectively. The vertical axis indicates the coolant temperature at each position of the pipe 87 .

Referring to FIG. 5, when the refrigerant is insufficient, the refrigerant passing through the capillary tube 71 has a large amount of gaseous components. Therefore, when the refrigerant is heated by the heater 72, the refrigerant evaporates and the temperature of the refrigerant rises. (superheat > 0). Therefore, the temperature T2 of the refrigerant after the heater 72 heats the refrigerant is higher than the temperature T1 of the refrigerant before the heater 72 heats the refrigerant.

When the refrigerant is a non-azeotropic refrigerant, the temperature rise of the refrigerant caused by the heater 72 when the refrigerant is insufficient can be distinguished from the temperature rise of the refrigerant caused by the heater 72 during normal operation (temperature rise based on the temperature gradient of the refrigerant). Also, the heating amount of the heater 72 is appropriately set.

Thus, in the refrigerant amount detection unit 70, it is possible to determine whether or not there is a shortage of refrigerant in the refrigerant circuit based on the amount of increase in the temperature of the refrigerant when the heater 72 heats the refrigerant.

Control device 100 acquires intake temperature Ts of compressor 10 detected by intake temperature sensor 302 . The control device 100 acquires the suction pressure LP of the compressor 10 detected by the suction pressure sensor 90 . Control device 100 calculates saturation temperature ST(LP) of suction pressure LP. Control device 100 calculates suction superheat SH of compressor 10 by subtracting saturation temperature ST (LP) of suction pressure LP of compressor 10 from suction temperature Ts of compressor 10 .

The control device 100 acquires the refrigerant evaporation temperature Te detected by the evaporation temperature sensor 303 . Note that the control device 100 may calculate the refrigerant evaporation temperature Te by converting the suction pressure LP detected by the suction pressure sensor 90 into the refrigerant saturated gas temperature.

The control device 100 determines whether or not the refrigerant circulating in the refrigerant circuit 5 is insufficient, and when it is determined that the refrigerant is insufficient, notifies the cause of the refrigerant shortage as follows.

When the difference (T2-T1) between the temperature T1 detected by the temperature sensor 73 of the refrigerant amount detection unit 70 and the temperature T2 detected by the temperature sensor 74 is equal to or greater than the threshold value Th1, the control device 100 switches the refrigerant circuit 5 It is judged that the refrigerant circulating inside is insufficient.

In the liquid back operation, since the refrigerant flows from the evaporator 60 to the compressor 10 while containing the liquid refrigerant, the suction superheat SH of the compressor 10 becomes small. Since a large amount of refrigerant moves to the suction side of the compressor 10 during the liquid back operation, the amount of refrigerant supplied to the refrigerant amount detector 70 decreases. As a result, it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient. Therefore, when it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient, the control device 100 determines that when the suction superheat degree SH of the compressor 10 is smaller than the threshold value Th2, the liquid Notify that you are driving.

Since the amount of refrigerant on the low-pressure side of the refrigerant circuit 5 is large when the operation with the high evaporation temperature Te is being performed, the amount of refrigerant supplied to the refrigerant amount detection unit 70 decreases. As a result, it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient. Therefore, when it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient and the refrigerant evaporation temperature Te is equal to or higher than the threshold value Th3, the controller 100 determines that the refrigerant evaporation temperature is a factor. Notifies you of high driving.

If it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient when the operation is not liquid back operation and the refrigerant evaporation temperature is low, the refrigerant may be leaking from the refrigerant circuit 5 to the outside. highly sexual. Therefore, when it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient, the control device 100 determines that the suction superheat degree SH of the compressor 10 is equal to or greater than the threshold Th2 and the evaporation temperature Te of the refrigerant is equal to or greater than the threshold Th2. If the value is less than Th3, the refrigerant leakage from the refrigerant circuit 5 to the outside is notified as a factor.

FIG. 6 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by the control device in the first embodiment. A series of processes shown in this flowchart are repeatedly executed while the refrigeration cycle device 1 is in steady operation.

Referring to FIG. 6, in step S101, control device 100 determines whether or not refrigerant shortage determination control is being executed. The refrigerant shortage determination control is executed for several minutes, for example, once an hour. When the refrigerant shortage determination control is not executed (NO in step S101), control device 100 shifts the process to RETURN without executing the subsequent series of processes. If it is determined that the refrigerant shortage determination control is being executed (YES in step S101), the process proceeds to step S102.

In step S102, the control device 100 turns on (opens) the electromagnetic valve 79 and turns on the heater 72 .

In step S103, the control device 100 acquires the detected values of the temperatures T1 and T2 from the temperature sensors 73 and 74 of the refrigerant amount detector 70, respectively.

In step S104, the control device 100 determines whether the difference (T2-T1) between the obtained temperature T2 and the temperature T1, that is, the amount of temperature increase of the refrigerant by the heater 72, is equal to or greater than the threshold value Th1. do. When it is determined that the temperature rise amount of the refrigerant by the heater 72 is equal to or greater than the threshold value Th1 (S104: YES), the control device 100 determines that the refrigerant circulating in the refrigerant circuit 5 is insufficient, and performs processing. goes to step S105. When it is determined that the temperature rise amount of the refrigerant by the heater 72 is less than the threshold value Th1 (S104: NO), the control device 100 determines that the refrigerant circulating in the refrigerant circuit 5 is not insufficient, and performs processing. goes to step S110.

In step S105, control device 100 determines whether or not suction superheat SH of compressor 10 is less than threshold value Th2. If it is determined that the suction superheat SH of the compressor 10 is less than the threshold value Th2 (S105: YES), the process proceeds to step S107. When it is determined that the suction superheat SH of the compressor 10 is equal to or greater than the threshold value Th2 (S105: NO), the process proceeds to step S106.

In step S106, control device 100 determines whether or not refrigerant evaporation temperature Te is equal to or higher than threshold Th3. If it is determined that the refrigerant evaporation temperature Te is equal to or higher than the threshold value Th3 (S106: YES), the process proceeds to step S108. When it is determined that the refrigerant evaporation temperature Te is less than the threshold value Th3 (S106: NO), the process proceeds to step S109.

In step S107, the control device 100 displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the liquid back operation.

In step S<b>108 , the control device 100 displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the operation in which the evaporation temperature of the refrigerant is high.

In step S109, the control device 100 displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient because the refrigerant sealed in the refrigerant circuit 5 has leaked to the outside.

In step S110, the control device 100 turns off (closes) the solenoid valve 79 and turns off the heater 72 .

As described above, when a non-azeotropic refrigerant is used, when the refrigerant is heated by the heater 72, the temperature of the refrigerant rises even if the amount of refrigerant is appropriate. Therefore, the threshold value Th1 in step S104 is determined by the type of refrigerant being used and the temperature of the heater 72 so that the amount of temperature rise of the refrigerant during normal operation by the heater 72 can be distinguished from the amount of temperature rise when the refrigerant is insufficient. It is appropriately set based on the heating amount.

As described above, in Embodiment 1, it is possible to determine whether or not there is a shortage of refrigerant based on the amount of temperature increase of the refrigerant by the heater 72 . Therefore, the accuracy of determination of the shortage of refrigerant depends on the accuracy of detection of the amount of temperature rise of the refrigerant by the heater 72 . Therefore, in the outdoor unit 2 according to the first embodiment, the refrigerant amount detection unit 70 is arranged at a location that is not easily affected by the wind that disturbs the detection of the amount of temperature rise. Specifically, the refrigerant amount detection unit 70 is arranged at a location that is less affected by airflow than the condenser 20 . The wind to be reduced includes the wind that has passed through the condenser 20, the wind that has not passed through the condenser 20, and the natural wind. As a result, it is possible to suppress an error in the amount of temperature rise due to the effect of the wind on the refrigerant amount detection unit 70 .

FIG. 7 is a diagram schematically showing the structure of the outdoor unit 2 of the refrigeration cycle device 1. As shown in FIG. Referring to FIG. 7 , the interior of outdoor unit 2 is partitioned into heat exchange chamber 202 and machine chamber 204 by partition plate (wall) 206 . The heat exchange chamber 202 accommodates a condenser 20, a liquid reservoir 30, a subcooling heat exchanger 40 (none of which are shown), and fans 22 and . The condenser 20 and the subcooling heat exchanger 40 (hereinafter sometimes collectively referred to as "heat exchange section") and the fans 22, 42 are provided on the side surface of the housing of the outdoor unit 2, and in this example , the heat exchange section is provided on the back side and the fans 22 and 42 are provided on the front side, and exhaust hot air from the heat exchange section flows from the back side of the heat exchange chamber 202 toward the front side. The machine room 204 accommodates the compressor 10 , each pipe, the suction pressure sensor 90 , the discharge pressure sensor 92 and the control device 100 .

In outdoor unit 2 according to Embodiment 1, refrigerant amount detection unit 70 is housed in machine room 204 . Inside the heat exchange chamber 202, there is a wind caused by the operation of the fans 22 and 42, or a natural wind when the fans are stopped. When the refrigerant amount detection unit 70 is arranged in the heat exchange chamber 202 through which the wind flows, the refrigerant amount detection unit 70 (especially the temperature sensors 73 and 74) is affected by the wind, and the temperature of the refrigerant by the heater 72 increases. Errors can occur in measuring the amount of rise. In this example, the refrigerant amount detection unit 70 is housed in the machine chamber 204 separated from the heat exchange chamber 202 by the partition plate 206, so it is not affected by the wind. Therefore, according to the outdoor unit 2, the amount of temperature rise of the refrigerant by the heater 72 can be measured with high accuracy.

Although the liquid reservoir 30 is arranged in the heat exchange chamber 202 in the above description, it may be arranged in the machine chamber 204 .

As described above, according to Embodiment 1, regardless of the degree of subcooling of the refrigerant or whether or not a non-azeotropic refrigerant is used, the refrigerant Deficiency can be determined.

According to Embodiment 1, it is possible to notify the operator or the user of the cause of the refrigerant shortage. As a result, it is possible to take measures according to the cause of the determination that the refrigerant is insufficient.

In the first embodiment, since the refrigerant amount detection unit 70 is arranged in the machine room 204 which is not affected by the wind, an error occurs in the above-described temperature rise amount due to the influence of the wind on the refrigerant amount detection unit 70. can be avoided. As a result, according to Embodiment 1, it is possible to accurately determine the shortage of refrigerant in the refrigerant circuit 5 .

Embodiment 2.
In the second embodiment, the high-temperature, high-pressure refrigerant on the discharge side of the compressor 10 is used instead of the heater 72 as the heat source in the refrigerant amount detector. Accordingly, the refrigerant amount detection section can be configured without separately providing the heater 72 .

FIG. 8 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 2. FIG. Referring to FIG. 8, this refrigeration cycle apparatus 1A includes an outdoor unit 2A and an indoor unit 3. As shown in FIG. The outdoor unit 2A includes a refrigerant amount detection unit 70A and a control device 100A, respectively, instead of the refrigerant amount detection unit 70 and the control device 100 in the outdoor unit 2 of Embodiment 1 shown in FIG.

Refrigerant amount detection portion 70A includes a heat exchange portion 78 in place of heater 72 in refrigerant amount detection portion 70 of the first embodiment shown in FIG. 1, and further includes temperature sensors 75-77. The heat exchange unit 78 is configured to exchange heat between the high-temperature, high-pressure refrigerant output from the compressor 10 and the refrigerant that has passed through the capillary tube 71 . The temperature sensor 73 detects the temperature of the refrigerant on the upstream side of the heat exchange section 78 , that is, the temperature T<b>1 of the refrigerant between the capillary tube 71 and the heat exchange section 78 . On the other hand, the temperature sensor 74 detects the temperature of the refrigerant on the downstream side of the heat exchange section 78 , that is, the temperature T<b>2 of the refrigerant downstream of the heat exchange section 78 and before joining the pipe 85 .

Temperature sensor 75 detects temperature T3 of the high-temperature, high-pressure refrigerant output from compressor 10, and outputs the detected value to control device 100A. The temperature sensor 76 detects the temperature T4 of the refrigerant output from the compressor 10 and passed through the heat exchange portion 78, and outputs the detected value to the control device 100A. That is, the temperature sensors 75 and 76 detect the temperature of the refrigerant supplied from the compressor 10 to the condenser 20 before and after passing through the heat exchange section 78, respectively. Temperature sensor 77 detects temperature T5 of the refrigerant sucked into compressor 10, and outputs the detected value to control device 100A.

The control device 100A determines whether or not there is a shortage of refrigerant in the refrigerant circuit 5A based on the amount of temperature rise of the refrigerant when the refrigerant flowing through the pipe 87 is heated by the heat exchange portion 78 . More specifically, the control device 100A determines that there is a shortage of refrigerant when the amount of temperature increase of the refrigerant by the heat exchange portion 78 is greater than or equal to the threshold value.

Here, since the amount of heating of the heat exchange section 78 changes depending on the operating state of the refrigerating cycle device 1A, the amount of temperature rise of the refrigerant in the pipe 87 in the heat exchanging section 78 also changes depending on the operating state of the refrigerating cycle device 1A. . In particular, when the refrigerant is a non-azeotropic refrigerant, the temperature rises when the gas-liquid two-phase refrigerant flowing through the pipe 87 is heated in the heat exchange section 78, even if there is no shortage of refrigerant. depends on the amount of heating. Moreover, even if the refrigerant is an azeotropic refrigerant, the temperature of the refrigerant may rise when the amount of heating of the heat exchange portion 78 is large.

Therefore, in the second embodiment, the amount of heating of the heat exchanging portion 78 is calculated, and based on the amount of heating, a threshold value (refrigerant in the heat exchanging portion 78 temperature rise threshold) is set. Thereby, even if the heating amount of the heat exchange part 78 changes with the operating conditions of the refrigerating cycle apparatus 1A, it is possible to accurately determine the lack of refrigerant.

The heating amount of the heat exchange portion 78 can be calculated, for example, as follows. A heating amount (W=J/s) of the heat exchange portion 78 is calculated by the following equation.

Amount of heating = G x H (1)
Here, G is the flow rate of refrigerant flowing from the compressor 10 to the heat exchange section 78 , and H is the enthalpy difference of the refrigerant flowing from the compressor 10 to the heat exchange section 78 before and after the heat exchange section 78 .

A refrigerant flow rate G (kg/hr) can be calculated by the following equation.
Refrigerant flow rate G=V×R×D (2)
Here, V is the displacement (m ³ ) of the compressor 10, that is, the refrigerant suction amount per revolution of the compressor 10. R is the rotation speed (1/hr or 1/s) of the compressor 10, and D is the density of the refrigerant (kg/m ³ ). The density D is a quantity determined by the refrigerant temperature and pressure on the suction side of the compressor 10, and can be calculated from the temperature T5 detected by the temperature sensor 77 and the suction pressure LP detected by the suction pressure sensor 90. can.

Also, the enthalpy difference H (kJ/kg) can be calculated by the following equation.
Enthalpy difference H=H3-H4 (3)
Here, H3 is the enthalpy of the refrigerant supplied from the compressor 10 to the heat exchange section 78, and H4 is the enthalpy of the refrigerant after passing through the heat exchange section 78. The enthalpy H3 is determined by the discharge pressure HP of the compressor 10 and the temperature of the refrigerant before passing through the heat exchange section 78. The discharge pressure HP detected by the discharge pressure sensor 92 and the temperature sensor 75 It can be obtained from the temperature T3. The enthalpy H4 is determined by the discharge pressure HP of the compressor 10 and the temperature of the refrigerant after passing through the heat exchange section 78, and can be obtained from the discharge pressure HP and the temperature T4 detected by the temperature sensor 76. can.

FIG. 9 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by the control device 100A in the second embodiment. A series of processes shown in this flowchart are repeatedly executed while the refrigeration cycle apparatus 1A is in steady operation.

Referring to FIG. 9, in step S201, control device 100A determines whether or not refrigerant shortage determination control is being executed. The refrigerant shortage determination control is executed for several minutes, for example, once an hour. When the refrigerant shortage determination control is not executed (NO in step S201), the control device 100A shifts the process to RETURN without executing the subsequent series of processes. If it is determined that the refrigerant shortage determination control is being executed (YES in step S201), the process proceeds to step S202.

In step S202, the control device 100A acquires detected values of the temperatures T1 to T5 from the temperature sensors 73 to 77, respectively, acquires the rotational speed R of the compressor 10, and further from the suction pressure sensor 90 and the discharge pressure sensor 92, respectively. Detected values of suction pressure LP and discharge pressure HP are acquired.

In step S203, the control device 100A calculates the refrigerant flow rate G using the above equation (2), and calculates the enthalpy difference H using the above equation (3).

In step S204, the control device 100A multiplies the calculated refrigerant flow rate G and the enthalpy difference H to calculate the heating amount (G×H) of the heat exchange section 78. FIG.

In step S205, the control device 100A sets a threshold value Th4 (a Set the threshold value for the temperature rise amount of the refrigerant).

The relationship between the amount of heating and the threshold value Th4 is obtained in advance by preliminary evaluation, simulation, or the like depending on the type of refrigerant used, and is stored in the ROM of the control device 100A. Qualitatively, the larger the amount of heating, the larger the threshold Th4. When the amount of heating is the same, the threshold for the non-azeotropic refrigerant is higher than the threshold for the azeotropic refrigerant.

In step S206, control device 100A sets the difference (T2-T1) between temperature T2 and temperature T1 acquired in step S202, that is, the amount of temperature rise of the refrigerant flowing through piping 87 in heat exchanging section 78 to threshold value Th4. It is determined whether or not the above is satisfied. When it is determined that the refrigerant temperature rise amount is equal to or greater than the threshold value Th4 (S206: YES), the control device 100A determines that the refrigerant circulating in the refrigerant circuit 5 is insufficient, and the process proceeds to step S207. proceed to When it is determined that the refrigerant temperature rise amount is less than the threshold value Th4 (S206: NO), the control device 100A determines that the refrigerant circulating in the refrigerant circuit 5 is not insufficient, and returns. to migrate.

In step S207, the controller 100A determines whether or not the suction superheat SH of the compressor 10 is less than the threshold value Th2. If it is determined that the suction superheat SH of the compressor 10 is less than the threshold value Th2 (S207: YES), the process proceeds to step S209. When it is determined that the suction superheat SH of the compressor 10 is equal to or greater than the threshold value Th2 (S207: NO), the process proceeds to step S208.

In step S208, the control device 100A determines whether or not the refrigerant evaporation temperature Te is equal to or higher than a threshold value Th3. If it is determined that the refrigerant evaporation temperature Te is equal to or higher than the threshold Th3 ( S208: YES), the process proceeds to step S210. When it is determined that the refrigerant evaporation temperature Te is less than the threshold value Th3 (S208: NO), the process proceeds to step S211.

In step S209, the control device 100A displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the liquid back operation.

In step S210, the control device 100A displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the operation in which the evaporation temperature of the refrigerant is high.

In step S211, the control device 100A displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient because the refrigerant sealed in the refrigerant circuit 5 has leaked to the outside.

As described above, according to the second embodiment, instead of the heater 72, the heat exchange section 78 using the high-temperature, high-pressure refrigerant on the discharge side of the compressor 10 is provided as the heat source in the refrigerant amount detection section 70A. , the refrigerant quantity detector can be constructed without providing the heater 72 .

Further, the amount of heating of the heat exchange portion 78 varies depending on the operating state of the refrigeration cycle device 1A. is set based on the heating amount of the heat exchange portion 78, it is possible to accurately determine the refrigerant shortage even if the operating state of the refrigeration cycle apparatus 1A changes.

According to the second embodiment, as in the first embodiment, it is possible to notify the operator or the user of the cause of the refrigerant shortage. As a result, it is possible to take measures according to the cause of the determination that the refrigerant is insufficient.

Embodiment 3.
FIG. 10 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 3. FIG. Referring to FIG. 10, this refrigeration cycle apparatus 1C includes an outdoor unit 2C and an indoor unit 3. As shown in FIG. The outdoor unit 2C includes a control device 100C instead of the control device 100 of the outdoor unit 2 of Embodiment 1 shown in FIG. The outdoor unit 2</b>C further includes a condensation temperature sensor 305 and a liquid refrigerant temperature sensor 304 .

A condensing temperature sensor 305 is provided at the inlet of the subcooling heat exchanger 40 . A condensation temperature sensor 305 detects the temperature of the refrigerant as the condensation temperature Tx.

A liquid refrigerant temperature sensor 304 is provided at the outlet of the subcooling heat exchanger 40 . The liquid refrigerant temperature sensor 304 detects the temperature of the refrigerant as the liquid refrigerant temperature Ty.

The controller 100C calculates the subcooling degree SC of the refrigerant at the outlet of the subcooling heat exchanger 40 by subtracting the liquid refrigerant temperature Ty from the condensation temperature Tx.

SC=Tx-Ty (4)
The control device 100C determines that the refrigerant circulating in the refrigerant circuit 5 is insufficient when the subcooling degree SC is equal to or less than the threshold value Th5.

FIG. 11 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by the control device 100C in the third embodiment. A series of processes shown in this flow chart are repeatedly executed while the refrigeration cycle device 1C is in steady operation.

Referring to FIG. 11, in step S301, control device 100C determines whether or not refrigerant shortage determination control is being executed. The refrigerant shortage determination control is executed for several minutes, for example, once an hour. When the refrigerant shortage determination control is not executed (NO in step S301), the control device 100C shifts the process to RETURN without executing the subsequent series of processes. If it is determined that refrigerant shortage determination control is being executed (YES in step S301), the process proceeds to step S302.

In step S<b>302 , the control device 100</b>C acquires the condensation temperature Tx from the condensation temperature sensor 305 and acquires the liquid refrigerant temperature Ty from the liquid refrigerant temperature sensor 304 .

In step S303, the control device 100C calculates the subcooling degree SC of the refrigerant at the outlet of the subcooling heat exchanger 40 based on the condensation temperature Tx and the liquid refrigerant temperature Ty.

In step S304, control device 100C determines whether or not degree of supercooling SC is equal to or less than threshold value Th5. When it is determined that the degree of supercooling SC is equal to or less than the threshold value Th5 (S304: YES), the control device 100C determines that the refrigerant circulating in the refrigerant circuit 5 is insufficient, and the process proceeds to step S305. move on. When it is determined that the degree of supercooling SC exceeds the threshold value Th5 (S304: NO), the control device 100C determines that the refrigerant circulating in the refrigerant circuit 5 is not insufficient, and shifts the process to return. do.

In step S305, the controller 100C determines whether or not the suction superheat SH of the compressor 10 is less than the threshold value Th2. If it is determined that the suction superheat degree SH of the compressor 10 is less than the threshold value Th2 (S305: YES), the process proceeds to step S307. When it is determined that the suction superheat degree SH of the compressor 10 is equal to or greater than the threshold value Th2 (S305: NO), the process proceeds to step S306.

In step S306, the control device 100C determines whether or not the refrigerant evaporation temperature Te is equal to or higher than a threshold value Th3. If it is determined that the refrigerant evaporation temperature Te is equal to or higher than the threshold value Th3 (S306: YES), the process proceeds to step S308. When it is determined that the refrigerant evaporation temperature Te is less than the threshold value Th3 (S306: NO), the process proceeds to step S309.

In step S307, the control device 100C displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the liquid back operation.

In step S308, the control device 100C displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the operation with a high refrigerant evaporation temperature.

In step S309, the control device 100C displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient because the refrigerant sealed in the refrigerant circuit 5 has leaked to the outside.

As described above, according to Embodiment 3, it is possible to determine whether or not the refrigerant is insufficient based on the degree of supercooling SC of the refrigerant at the outlet of the supercooling heat exchanger 40 .

According to Embodiment 3, as in Embodiments 1 and 2, it is possible to notify the operator or the user of the cause of the refrigerant shortage. As a result, it is possible to take measures according to the cause of the determination that the refrigerant is insufficient.

Embodiment 4.
FIG. 12 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 4. FIG. Referring to FIG. 12, this refrigeration cycle apparatus 1D includes an outdoor unit 2D and an indoor unit 3. As shown in FIG. The outdoor unit 2D includes a control device 100D instead of the control device 100 of the outdoor unit 2 of Embodiment 1 shown in FIG. The outdoor unit 2</b>D further includes a condensation temperature sensor 305 , a liquid refrigerant temperature sensor 304 and an outside air temperature sensor 301 .

Outside air temperature sensor 301 is provided around condenser 20 . The outside air temperature sensor 301 detects the outside air temperature To.

A condensing temperature sensor 305 is provided at the inlet of the subcooling heat exchanger 40 . A condensation temperature sensor 305 detects the temperature of the refrigerant as the condensation temperature Tx.

A liquid refrigerant temperature sensor 304 is provided at the outlet of the subcooling heat exchanger 40 . The liquid refrigerant temperature sensor 304 detects the temperature of the refrigerant as the liquid refrigerant temperature Ty.

The control device 100D calculates the subcooling degree SC of the refrigerant at the outlet of the subcooling heat exchanger 40 by subtracting the liquid refrigerant temperature Ty from the condensation temperature Tx.

The control device 100D determines the degree of subcooling of the refrigerant at the outlet of the subcooling heat exchanger 40 (condensing temperature Tx - liquid refrigerant temperature Ty) with the maximum temperature difference of the subcooling heat exchanger 40 (condensing temperature Tx - outside air temperature To). By dividing, the temperature efficiency ε of the subcooling heat exchanger 40 is calculated.

ε=(Tx−Ty)/(Tx−To) (5)
The control device 100D determines that the refrigerant circulating in the refrigerant circuit 5 is insufficient when the temperature efficiency ε is equal to or lower than the threshold value Th6.

FIG. 13 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by the controller 100D in the fourth embodiment. A series of processes shown in this flowchart are repeatedly executed while the refrigeration cycle device 1D is in steady operation.

Referring to FIG. 13, in step S401, control device 100D determines whether or not refrigerant shortage determination control is being executed. The refrigerant shortage determination control is executed for several minutes, for example, once an hour. When the refrigerant shortage determination control is not executed (NO in step S401), the control device 100D shifts the process to RETURN without executing the subsequent series of processes. If it is determined that refrigerant shortage determination control is being executed (YES in step S401), the process proceeds to step S402.

In step S<b>402 , the control device 100</b>D acquires the condensation temperature Tx from the condensation temperature sensor 305 , acquires the liquid refrigerant temperature Ty from the liquid refrigerant temperature sensor 304 , and acquires the outside air temperature To from the outside air temperature sensor 301 .

In step S403, the control device 100D calculates the temperature efficiency ε of the subcooling heat exchanger 40 based on the outside air temperature To, the condensing temperature Tx, and the liquid refrigerant temperature Ty.

In step S404, the control device 100D determines whether or not the temperature efficiency ε of the subcooling heat exchanger 40 is equal to or less than the threshold value Th6. When it is determined that the temperature efficiency ε of the subcooling heat exchanger 40 is equal to or less than the threshold value Th6 (S404: YES), the control device 100D determines that the refrigerant circulating in the refrigerant circuit 5 is insufficient. , the process proceeds to step S405. When it is determined that the temperature efficiency ε of the supercooling heat exchanger 40 exceeds the threshold Th6 (S404: NO), the control device 100D determines that the refrigerant circulating in the refrigerant circuit 5 is not insufficient, Move processing to return.

In step S405, control device 100D determines whether or not suction superheat SH of compressor 10 is less than threshold value Th2. If it is determined that the suction superheat SH of the compressor 10 is less than the threshold value Th2 (S405: YES), the process proceeds to step S407. When it is determined that the suction superheat SH of the compressor 10 is equal to or greater than the threshold value Th2 (S405: NO), the process proceeds to step S406.

In step S406, the control device 100D determines whether or not the refrigerant evaporation temperature Te is equal to or higher than a threshold value Th3. If it is determined that the refrigerant evaporation temperature Te is equal to or higher than the threshold value Th3 (S406: YES), the process proceeds to step S408. If it is determined that the refrigerant evaporation temperature Te is less than the threshold value Th3 (S406: NO), the process proceeds to step S409.

In step S407, the control device 100D displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the liquid back operation.

In step S<b>408 , the control device 100</b>D displays on the display device 150 that it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to operation with a high refrigerant evaporation temperature.

In step S409, the control device 100D displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient because the refrigerant sealed in the refrigerant circuit 5 has leaked to the outside.

As described above, according to Embodiment 4, it is possible to determine whether or not the refrigerant is insufficient based on the temperature efficiency ε of the supercooling heat exchanger 40 .

According to Embodiment 4, as in Embodiments 1 to 3, it is possible to notify the operator or the user of the cause of the refrigerant shortage. As a result, it is possible to take measures according to the cause of the determination that the refrigerant is insufficient.

Embodiment 5.
14 is an overall configuration diagram of a refrigeration cycle apparatus using an outdoor unit according to Embodiment 5. FIG. Referring to FIG. 14, this refrigeration cycle apparatus 1B includes an outdoor unit 2B and an indoor unit 3. As shown in FIG. The outdoor unit 2B includes a control device 100B instead of the control device 100 of the outdoor unit 2 of Embodiment 1 shown in FIG.

FIG. 15 is a diagram for explaining a refrigerant shortage determination process by the control device according to the fifth embodiment. As shown in FIG. 15, the control device 100B calculates the temperature rise amount (T2-T1) of the coolant by the heater 72 at intervals of A seconds (t1, t2, t3, . . . ). The control device 100B calculates an average value M of the latest three coolant temperature rise amounts. The control device 100B determines that the refrigerant is insufficient when the average value M becomes equal to or greater than the threshold value Th1. The control device 100B determines that there is no shortage of refrigerant when the average value M is less than the threshold value Th1 continuously for B minutes.

FIG. 16 is a flowchart showing an example of a refrigerant shortage determination processing procedure executed by the control device 100B in the fifth embodiment. A series of processes shown in this flowchart are repeatedly executed while the refrigeration cycle device 1B is in steady operation.

Referring to FIG. 16, in step S501, control device 100B determines whether or not refrigerant shortage determination control is being executed. The refrigerant shortage determination control is executed for several minutes, for example, once an hour. When the refrigerant shortage determination control is not executed (NO in step S501), control device 100B shifts the process to RETURN without executing the subsequent series of processes. If it is determined that the refrigerant shortage determination control is being executed ( YES in step S501), the process proceeds to step S502.

In step S502, the control device 100B turns on (opens) the solenoid valve 79 and turns on the heater 72 .

In step S503, when the solenoid valve 79 is turned ON and the heater 72 is turned ON, or when A seconds have passed since the time when the temperature T1 or T2 was detected last time, the process proceeds to step S504.

In step S504, the control device 100B acquires the detected values of the temperatures T1 and T2 from the temperature sensors 73 and 74 of the refrigerant amount detector 70, respectively.

In step S505, the three latest average values of the difference (T2-T1) between the temperature T2 and the temperature T1, that is, the three latest average values M of the amount of temperature rise of the refrigerant by the heater 72 are calculated.

In step S506, control device 100B determines whether average value M is equal to or greater than threshold Th1. When it is determined that the average value M is equal to or greater than the threshold value Th1 (S506: YES), the control device 100B determines that the refrigerant circulating in the refrigerant circuit 5 is insufficient, and the process proceeds to step S508. . When it is determined that the average value M is less than the threshold value Th1 (S506: NO), the control device 100B determines that the refrigerant circulating in the refrigerant circuit 5 is not insufficient, and the process proceeds to step S507. .

In step S507, when B minutes have passed since the time when the solenoid valve 79 was turned ON and the heater 72 was turned ON (S507: YES), the process proceeds to step S513. When B minutes have not elapsed since the time when the solenoid valve 79 was turned on and the heater 72 was turned on (S507: NO), the process returns to step S503.

In step S508, control device 100B determines whether or not suction superheat SH of compressor 10 is less than threshold value Th2. When it is determined that the suction superheat degree SH of the compressor 10 is less than the threshold value Th2 (S508: YES), the process proceeds to step S510. When it is determined that the suction superheat degree SH of the compressor 10 is equal to or greater than the threshold value Th2 (S510: NO), the process proceeds to step S511.

In step S509, the control device 100B determines whether or not the evaporation temperature Te of the refrigerant is equal to or higher than a threshold value Th3. If it is determined that the refrigerant evaporation temperature Te is equal to or higher than the threshold Th3 ( S509: YES), the process proceeds to step S511. When it is determined that the refrigerant evaporation temperature Te is less than the threshold value Th3 (S509: NO), the process proceeds to step S512.

In step S510, the control device 100B displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to the liquid back operation.

In step S<b>511 , the control device 100</b>B displays on the display device 150 that it is determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient due to operation with a high refrigerant evaporation temperature.

In step S512, the control device 100B displays on the display device 150 that it has been determined that the refrigerant circulating in the refrigerant circuit 5 is insufficient because the refrigerant sealed in the refrigerant circuit 5 has leaked to the outside.

In step S513, the control device 100B turns off (closes) the electromagnetic valve 79 and turns off the heater 72 .

As described above, according to Embodiment 5, it is possible to prevent an erroneous determination as to whether or not the refrigerant is insufficient when there is variation in the detected temperatures T1 and T2.

In the above-described embodiment, the control device determines the lack of refrigerant using the average value of the amount of temperature rise for a plurality of times in the first embodiment, but the present invention is not limited to this.

The control device may use an average value of a plurality of temperature rise amounts in the second embodiment to determine the shortage of refrigerant. The control device may use the average value of the degree of supercooling at the outlet of the supercooling heat exchanger in Embodiment 3 for a plurality of times to determine the shortage of refrigerant. The control device may use the average value of the temperature efficiency of the supercooling heat exchanger of the fourth embodiment for a plurality of times to determine the shortage of the refrigerant.

It is also planned that the embodiments disclosed this time will be combined as appropriate within a technically consistent range. And the embodiment disclosed this time should be considered as an illustration and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the description of the above-described embodiments, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

Reference Signs List 1, 1A, 1B, 1C, 1D refrigerating cycle device, 2, 2A, 2B, 2C, 2D outdoor unit, 3 indoor unit, 10 compressor, 20 condenser, 22, 42, 62 fan, 30 liquid reservoir, 40 Subcooling heat exchanger, 45 sight glass, 50 expansion valve, 60 evaporator, 70, 70A refrigerant amount detector, 71 capillary tube, 72 heater, 73 to 77, 301, 302, 304, 305 temperature sensor, 78 heat exchange Part, 79 solenoid valve, 80 to 87 piping, 90, 92 pressure sensor, 100, 100A, 100B, 100C, 100D control device, 102 CPU, 104 memory, 150 display device, 201 temperature sensor, 202 heat exchange chamber, 204 machine Chamber, 206 dividers, 208 boxes.

Claims (14)

An outdoor unit connected to an indoor unit to form a refrigeration cycle device,
a compressor that compresses a refrigerant;
a condenser that condenses the refrigerant output from the compressor ;
a liquid reservoir for storing high-pressure liquid refrigerant condensed by the condenser ,
The compressor , the condenser , and the liquid reservoir together with an expansion mechanism and an evaporator included in the indoor unit form a refrigerant circuit for circulating the refrigerant,
The outdoor unit further comprises
determining whether the refrigerant circulating in the refrigerant circuit is insufficient by determining whether the amount of liquid refrigerant accumulated in the liquid reservoir is insufficient according to the first criterion; When it is determined that the refrigerant is insufficient, a second determination criterion different from the first determination criterion is used to determine the cause of the determination that the refrigerant is insufficient, and the determined cause is determined. A control device is provided to notify the user, and the reason for determining that the refrigerant is insufficient is any of liquid back operation, operation in which the evaporation temperature of the refrigerant is high, and leakage of the refrigerant from the refrigerant circuit. Yes ,
The outdoor unit further comprises
a bypass circuit configured to return part of the refrigerant on the discharge side of the condenser to the compressor without passing through the indoor unit;
a heater configured to heat the refrigerant flowing through the bypass circuit; a pre-heating temperature sensor that detects the temperature of the refrigerant before being heated by the heater; and the refrigerant heated by the heater. A refrigerant amount detection unit including a post-heating temperature sensor that detects the temperature of
The control device uses the amount of temperature rise calculated from the temperature detected by the post-heating temperature sensor and the temperature detected by the pre-heating temperature sensor to determine whether the amount of liquid refrigerant accumulated in the liquid reservoir is sufficient. The outdoor unit determines whether or not When it is determined that the refrigerant is insufficient, the control device determines that the cause is the liquid back operation when the suction superheat degree of the compressor is smaller than a first threshold value. The outdoor unit according to claim 1, which notifies. If the refrigerant evaporation temperature is equal to or higher than a second threshold value when it is determined that the refrigerant is insufficient, the control device determines that the operation is performed with the refrigerant evaporation temperature being high as the factor. The outdoor unit according to claim 1, which notifies that. When it is determined that the refrigerant is insufficient, the control device is configured such that the degree of suction superheat of the compressor is equal to or higher than a first threshold and the evaporation temperature of the refrigerant is lower than a second threshold. 2 . The outdoor unit according to claim 1 , wherein the leakage of the refrigerant from the refrigerant circuit is notified as the factor in the event of a situation. The outdoor unit according to claim 1 , wherein the controller determines that the refrigerant circulating in the refrigerant circuit is insufficient when the amount of temperature rise is equal to or greater than a third threshold. 2. The control device according to claim 1 , wherein the control device determines that the refrigerant circulating in the refrigerant circuit is insufficient when an average value of the amount of temperature rise at a plurality of times is equal to or greater than a third threshold value. outdoor unit. 2. The outdoor unit according to claim 1, wherein said refrigerant amount detection unit is provided at a location less affected by airflow than said condenser. The outdoor unit according to claim 1 , wherein the heater is a heater. The outdoor unit according to claim 1 , wherein the heater is a refrigerant pipe on the discharge side of the compressor. further comprising a valve provided in the bypass circuit and configured to switch between flowing and shutting off the refrigerant in the bypass circuit;
The control device is
Controlling the valve to an open state during execution of determination control for determining whether the refrigerant circulating in the refrigerant circuit is insufficient,
The outdoor unit according to claim 1 , wherein said valve is controlled to be closed while said determination control is not being executed. The outdoor unit according to claim 1 , further comprising a decompression device provided in said bypass circuit and configured to reduce the pressure of said refrigerant flowing through said bypass circuit. An outdoor unit connected to an indoor unit to form a refrigeration cycle device,
a compressor that compresses a refrigerant;
a condenser that condenses the refrigerant output from the compressor;
a liquid reservoir for storing high-pressure liquid refrigerant condensed by the condenser,
The compressor, the condenser, and the liquid reservoir together with an expansion mechanism and an evaporator included in the indoor unit form a refrigerant circuit for circulating the refrigerant,
The outdoor unit further comprises
determining whether the refrigerant circulating in the refrigerant circuit is insufficient by determining whether the amount of liquid refrigerant accumulated in the liquid reservoir is insufficient according to the first criterion; When it is determined that the refrigerant is insufficient, a second determination criterion different from the first determination criterion is used to determine the cause of the determination that the refrigerant is insufficient, and the determined cause is determined. A control device is provided to notify the user, and the reason for determining that the refrigerant is insufficient is any of liquid back operation, operation in which the evaporation temperature of the refrigerant is high, and leakage of the refrigerant from the refrigerant circuit. can be,
The outdoor unit further comprises
A supercooling heat exchanger that supercools the refrigerant that has flowed out of the condenser,
The outdoor unit, wherein the control device determines that the amount of liquid refrigerant accumulated in the liquid reservoir is insufficient when the degree of supercooling in the supercooling heat exchanger is equal to or less than a fourth threshold value. An outdoor unit connected to an indoor unit to form a refrigeration cycle device,
a compressor that compresses a refrigerant;
a condenser that condenses the refrigerant output from the compressor;
a liquid reservoir for storing high-pressure liquid refrigerant condensed by the condenser,
The compressor, the condenser, and the liquid reservoir together with an expansion mechanism and an evaporator included in the indoor unit form a refrigerant circuit for circulating the refrigerant,
The outdoor unit further comprises
determining whether the refrigerant circulating in the refrigerant circuit is insufficient by determining whether the amount of liquid refrigerant accumulated in the liquid reservoir is insufficient according to the first criterion; When it is determined that the refrigerant is insufficient, a second determination criterion different from the first determination criterion is used to determine the cause of the determination that the refrigerant is insufficient, and the determined cause is determined. A control device is provided to notify the user, and the reason for determining that the refrigerant is insufficient is any of liquid back operation, operation in which the evaporation temperature of the refrigerant is high, and leakage of the refrigerant from the refrigerant circuit. can be,
The outdoor unit further comprises
A supercooling heat exchanger that supercools the refrigerant that has flowed out of the condenser,
The outdoor unit, wherein the control device determines that the amount of liquid refrigerant accumulated in the liquid reservoir is insufficient when the temperature efficiency of the subcooling heat exchanger is equal to or lower than a fifth threshold value. The outdoor unit according to any one of claims 1 to 13 ;
A refrigeration cycle apparatus comprising: the indoor unit connected to the outdoor unit.

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