WO2021111561A1 - Outdoor unit and refrigeration cycle device - Google Patents

Abstract

An outdoor unit (2) comprises a first flow path (F1), a second flow path (F2), stand-up piping (71), a flow rate adjustment device (73), a refrigerant heating device (75), a dryness increase device (150), a temperature sensor (122), and a notification device (101). A compressor (10) and a condenser (20) are arranged in the first flow path (F1). The second flow path (F2) branches from a branch point (BP1) and is configured so as to return the refrigerant having passed through the condenser (20) to the compressor (10). The stand-up piping (71) is installed at the branch point (BP1). The dryness increase device (150) increases the dryness of the refrigerant after passing through the condenser (20) in a refrigerant shortage detection mode more than in the normal mode. The temperature sensor (122) detects the temperature (T1) of the refrigerant that has passed through the refrigerant heating device (75). The notification device (101) provides notification of a refrigerant shortage according to the output of the temperature sensor (122) in the refrigerant shortage detection mode.

Description

Outdoor unit and refrigeration cycle device

The present invention relates to an outdoor unit and a refrigeration cycle device.

In International Publication No. 2016/135904, the refrigerant filled in the refrigerant circuit is filled with "temperature efficiency", which is the value obtained by dividing the degree of supercooling of the refrigerant at the outlet of the supercooler by the maximum temperature difference of the supercooler. A refrigerating apparatus including a refrigerant amount determining unit for determining the amount is disclosed.

International Publication No. 2016/135904

With the method described in International Publication No. 2016/135904, it may not be possible to detect the decrease in the amount of refrigerant from the time when the amount of refrigerant begins to decrease until the state in which the shortage of refrigerant actually progresses.

An object of the present invention is to provide an outdoor unit and a refrigeration cycle device capable of detecting a refrigerant shortage at an early stage.

The present disclosure relates to an outdoor unit of a refrigeration cycle device having a normal mode and a refrigerant shortage detection mode and configured to be connected to a load device including an expansion device and an evaporator. The outdoor unit is connected to a load device to form a circulation flow path through which the refrigerant circulates, a compressor and a condenser arranged in the first flow path, and a direction in which the refrigerant circulates. In the second flow path configured to branch from the branch point of the first flow path downstream of the condenser and return the refrigerant that has passed through the condenser to the compressor, and a gas-liquid separation structure provided at the branch point. In the refrigerant shortage detection mode, the dryness of the refrigerant after passing through the flow control device and the refrigerant heating device, which are arranged in the second flow path in order from the branch point, is increased as compared with the normal mode. A temperature increasing device, a temperature sensor that detects the temperature of the refrigerant that has passed through the refrigerant heating device of the second flow path, and a notification device that notifies that the refrigerant is insufficient according to the output of the temperature sensor in the refrigerant shortage detection mode. And.

According to the outdoor unit of the present disclosure, since it has a refrigerant shortage detection mode that increases the dryness of the refrigerant flowing in the bypass flow path as compared with the normal operation, it is possible to detect the refrigerant shortage at an early stage.

It is a figure which shows the structure of the refrigerating cycle apparatus 1 which concerns on Embodiment 1. FIG. It is a figure for demonstrating the state in which gas-liquid separation cannot be performed in a gas-liquid separation mechanism. It is a figure for demonstrating the state in which gas-liquid separation is possible in a gas-liquid separation mechanism. It is a Moriel diagram which shows the refrigerating cycle when the amount of a refrigerant is appropriate. It is a Moriel diagram which shows the refrigeration cycle when the amount of refrigerant is insufficient. It is a flowchart for demonstrating the control of the rotation speed of a fan in a normal operation. It is a flowchart for demonstrating control in a refrigerant shortage detection mode. It is a figure which shows the relationship between the rotation speed of a fan, the amount of a refrigerant, and the dryness of a refrigerant. It is a flowchart which shows the detail of the process (S14) which detects the amount of a refrigerant. This is an example of a map for obtaining the amount of refrigerant from the rotation speed of a fan. This is an example of a map for obtaining the amount of refrigerant from the frequency of the compressor. It is a figure which shows the structure of the refrigerating cycle apparatus 201 which concerns on Embodiment 2. FIG. This is an example of a map for obtaining the amount of refrigerant from the opening degree of the expansion valve.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a plurality of embodiments will be described, but it is planned from the beginning of the application that the configurations described in the respective embodiments are appropriately combined. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

Embodiment 1.
FIG. 1 is a diagram showing a configuration of a refrigeration cycle device 1 according to a first embodiment. With reference to FIG. 1, the refrigeration cycle device 1 includes an outdoor unit 2, a load device 3, and extension pipes 84 and 88.

The outdoor unit 2 of the refrigeration cycle device 1 is configured to be connected to the load device 3 by extension pipes 84 and 88.

The outdoor unit 2 includes a compressor 10, a condenser 20, a liquid receiver (receiver) 30, and pipes 80 to 83, 89. The liquid receiver 30 is arranged between the pipe 82 and the condenser 20 and is configured to store the refrigerant.

The flow path F1 from the compressor 10 to the connection port to the load device 3 via the condenser 20 and the liquid receiver 30 is configured to form a circulation flow path through which the refrigerant circulates together with the load device 3. Hereinafter, this circulation flow path is also referred to as a "main circuit" of the refrigeration cycle.

The load device 3 includes an expansion device 50, an evaporator 60, and pipes 85, 86, 87. The expansion device 50 is, for example, a temperature expansion valve that is controlled independently of the outdoor unit 2.

The compressor 10 compresses the refrigerant sucked from the pipe 89 and discharges it to the pipe 80. The compressor 10 has a suction port G1 and a discharge port G2. The compressor 10 is configured to suck the refrigerant that has passed through the evaporator 60 from the suction port G1 and discharge the refrigerant from the discharge port G2 toward the condenser 20.

The outdoor unit 2 further includes a start-up pipe 71, a pipe 72, a flow rate adjusting device 73, a pipe 74, and a refrigerant heating device 75. The pipe 72 branches from the pipe 82 connected to the outlet of the liquid receiver 30 of the circulation flow path, and is connected to one end of the flow rate adjusting device 73. The pipe 74 connects one end of the flow rate adjusting device 73 to the pipe 89. The refrigerant heating device 75 is configured to heat the refrigerant that has passed through the flow rate adjusting device 73. As the refrigerant heating device 75, for example, an electric heater can be used. As the flow rate adjusting device 73, for example, a capillary tube can be typically used, but any device such as an orifice in which the cross-sectional area of the flow path is narrowed and a pressure difference is generated may be used. Further, an expansion valve may be used as the flow rate adjusting device 73. Hereinafter, the second flow path F2 that branches from the main circuit and sends the refrigerant to the compressor 10 via the flow rate adjusting device 73 is referred to as a “bypass flow path”.

In the refrigeration cycle device 1, the bypass flow path is branched from the portion where the start-up pipe 71 is connected to the pipe 82 connected to the outlet of the liquid receiver 30.

When the refrigerant leaks due to branching by the start-up pipe 71 and the refrigerant becomes insufficient, the two-phase refrigerant mixed with the gas refrigerant is introduced into the pipe 72.

When the compressor has an intermediate pressure port, the connection destination of the bypass flow path may be an intermediate pressure port instead of the suction port of the compressor 10.

The compressor 10 is configured to adjust the rotation speed according to a control signal from the control device 100. By adjusting the rotation speed of the compressor 10, the circulation amount of the refrigerant is adjusted, and the refrigerating capacity of the refrigerating cycle device 1 can be adjusted. Various types of compressors 10 can be adopted, and for example, scroll type, rotary type, screw type and the like can be adopted.

The condenser 20 condenses the refrigerant discharged from the compressor 10 to the pipe 80 and flows it to the pipe 81. The condenser 20 is configured such that a high-temperature and high-pressure gas refrigerant discharged from the compressor 10 exchanges heat with the outside air. By this heat exchange, the heat-dissipated refrigerant condenses and changes into a liquid phase. The fan 22 supplies the condenser 20 with outside air through which the refrigerant exchanges heat in the condenser 20. By adjusting the rotation speed of the fan 22, the refrigerant pressure on the discharge side of the compressor 10 can be adjusted.

The outdoor unit 2 further includes pressure sensors 110, 111, temperature sensors 120, 121, 122, and a control device 100 for controlling the outdoor unit 2.

The pressure sensor 110 detects the pressure PL of the suction refrigerant of the compressor 10 and outputs the detected value to the control device 100. The pressure sensor 111 detects the pressure PH of the discharged refrigerant of the compressor 10 and outputs the detected value to the control device 100. The temperature sensor 120 detects the temperature TA of the outside air sent to the condenser 20 and outputs the detected value to the control device 100. The temperature sensor 121 detects the temperature TC of the refrigerant in the pipe 81 at the outlet of the condenser 20, and outputs the detected value to the control device 100. The temperature sensor 122 detects the temperature T1 of the refrigerant heated by the refrigerant heating device 75 after passing through the flow rate adjusting device 73, and outputs the detected value to the control device 100.

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 / outputting various signals, and the like. Consists of including. The CPU 102 expands the program stored in the ROM into a RAM or the like and executes the program. The program stored in the ROM is a program in which the processing procedure of the control device 100 is described. The control device 100 executes control of each device in the outdoor unit 2 according to these programs. This control is not limited to software processing, but can also be processed by dedicated hardware (electronic circuit).

As described above, in the first embodiment, a bypass flow path is provided from the outlet of the receiver 30 which is the high pressure part to the suction part of the compressor 10 which is the low pressure part. A flow rate adjusting device 73 and a refrigerant heating device 75 are arranged in the bypass flow path. A temperature sensor 122 and a pressure sensor 110 for detecting the low-pressure saturation temperature are provided at a portion that has passed through the refrigerant heating device 75. As the low pressure saturation temperature, the outlet temperature of the flow rate adjusting device 73 may be measured.

In such a configuration, a gas-liquid separation mechanism is provided at the branch point BP1 of the bypass flow path. FIG. 2 is a diagram for explaining a state in which gas-liquid separation is not possible in the gas-liquid separation mechanism. FIG. 3 is a diagram for explaining a state in which gas-liquid separation is possible in the gas-liquid separation mechanism.

With reference to FIGS. 2 and 3, the gas-liquid separation mechanism is composed of a rising pipe 71 rising from a pipe 82, which is a liquid pipe, in a direction opposite to gravity.

As shown in FIG. 2, when the dryness of the refrigerant flowing in the pipe 82 is small, a two-phase refrigerant in which a liquid refrigerant and a gas refrigerant are mixed flows in the start-up pipe 71 and the pipe 72. On the other hand, as shown in FIG. 3, when the dryness of the refrigerant flowing through the pipe 82 is large, the liquid refrigerant drops due to gravity in the middle of the start-up pipe 71, and the liquid refrigerant passes through the start-up pipe 71 to the pipe 72. Separated single-phase gas refrigerant flows.

When a two-phase refrigerant is flowing in the bypass flow path, heat is absorbed as latent heat for vaporizing the refrigerant even if it is heated by the refrigerant heating device 75. Therefore, the temperature T1 detected by the temperature sensor 122 coincides with the saturation temperature of the refrigerant. In this state, the degree of superheat of the refrigerant SH = 0.

On the other hand, when a gas-state refrigerant is flowing in the bypass flow path, when the refrigerant heating device 75 heats the refrigerant, the heat is absorbed by the refrigerant as sensible heat, so that the temperature of the refrigerant rises. Therefore, the temperature T1 detected by the temperature sensor 122 becomes higher than the saturation temperature of the refrigerant, and the degree of superheat of the refrigerant SH> 0.

FIG. 4 is a Moriel diagram showing a refrigeration cycle when the amount of refrigerant is appropriate. In FIG. 4, points A, B, and C correspond to points A, B, and C described in FIG. In the receiver 30, since a liquid refrigerant and a gas refrigerant are normally present, the state of the refrigerant at the outlet of the receiver 30 is on the saturated liquid line as shown at point A in FIG. That is, the inlet of the bypass flow path is in the liquid state (point A).

A flow rate corresponding to the differential pressure determined by the expansion device 50 and the evaporator 60 of the main circuit flows through the bypass passage. When the pressure is reduced by the flow rate adjusting device 73, the state of the refrigerant changes from the point A to the point B. Then, when the refrigerant is heated by the refrigerant heating device 75, the state of the refrigerant changes from the point B to the point C.

At this time, since a large amount of liquid refrigerant is flowing in the pipe 74, even if the point moves to the right by heating, the temperature of the refrigerant does not change at the saturation temperature because it does not exceed the saturated gas line.

Therefore, at point C, the degree of superheat SH is zero, so it can be determined that there is no shortage of refrigerant.

FIG. 5 is a Moriel diagram showing a refrigeration cycle when the amount of refrigerant is insufficient. In the state of lack of refrigerant, the dryness of the refrigerant at point A becomes large. Therefore, the state of the refrigerant at point A in FIG. 1 separated by the gas-liquid separation mechanism is the state shown at point A'in FIG. 5 on the Moriel diagram. When the pressure is reduced by the flow rate adjusting device 73, the state of the refrigerant changes from the point A'to the point B'. Then, when the refrigerant is heated by the refrigerant heating device 75, the state of the refrigerant changes from the point B'to the point C'.

At this time, since the liquid refrigerant does not flow through the pipe 74, when the point moves to the right after heating, the saturated gas line is exceeded. Since the heat is absorbed by the refrigerant as sensible heat, the temperature of the refrigerant becomes higher than the saturation temperature and the degree of superheat SH> 0, so that it can be determined that the refrigerant is insufficient.

For a two-phase refrigerant, the corresponding temperature (saturation temperature) can be determined by measuring the pressure with a pressure sensor. A conversion table showing the correspondence between the pressure and the saturation temperature is stored in the memory 104 of the control device 100 in advance. The control device 100 obtains the saturation temperature corresponding to the pressure PL from the conversion table, and calculates the difference from the temperature T1 actually measured by the temperature sensor. When the saturation temperature is T0, the superheat degree SH is SH = T1-T0.

FIG. 6 is a flowchart for explaining the control of the rotation speed of the fan during normal operation. In normal operation, the rotation speed of the fan 22 is determined so that each device works efficiently. For example, the difference between the temperature TC, which is the condensation temperature, and the outside air is set to be 10 ° C.

First, in step S1, the target temperature is set to a value obtained by adding α ° C. to the outside air temperature TA measured by the temperature sensor 120. α ° C. is set to a temperature at which the efficiency of heat exchange in the condenser 20 is good, for example, 10 ° C. Subsequently, in step S2, the condensation temperature TC is measured by the temperature sensor 121, and the measured condensation temperature TC is compared with the target temperature. If TC> target temperature (YES in S2), the control device 100 increases the rotation speed of the fan 22 and lowers the temperature TC in step S3. On the other hand, if TC <target temperature (YES in S4), the control device 100 reduces the rotation speed of the fan 22 in step S5 and raises the condensation temperature TC. If the condensation temperature TC matches the target temperature (NO in S2 and NO in S4), the control device 100 maintains the rotation speed of the fan 22 at the current rotation speed without changing it. In order to avoid frequent changes in the rotation speed of the fan 22, a difference may be provided in the target temperatures of steps S2 and S4 to provide hysteresis.

Here, the amount of the liquid refrigerant held in the liquid receiver 30 varies depending on the operating state of the refrigeration cycle device. Originally, the amount of the refrigerant should be a sufficient amount so that the liquid remains in the liquid receiver 30 even in the operating state where the liquid amount in the liquid receiver 30 is the smallest.

The operating state in which the amount of liquid in the receiver is the smallest is the state in which the condensation temperature TC is high (the pressure in the high-pressure part is rising due to the influence of the outside air temperature, the rotation speed of the fan, etc.). In this case, the density of the refrigerant in the main circuit increases and the volume decreases. Since the liquid refrigerant is discharged from the receiver 30 to the circulation circuit side by the amount of the volume reduction of the refrigerant in the main circuit, the amount of liquid in the receiver 30 is reduced.

In addition, when using multiple indoor units, if there is a stopped indoor unit, the refrigerant for that amount is stored in the receiver, so it is received when all of the multiple indoor units are in operation. The amount of liquid in the liquid container decreases.

Therefore, in order to enable detection of refrigerant shortage at an early stage, in the present embodiment, in the refrigerant shortage detection mode, the dryness of the receiver outlet portion provided with the gas-liquid separation mechanism is normally operated. It is increased more than the time, and the refrigerant shortage detection unit provided in the bypass flow path makes it easy to detect the refrigerant shortage.

FIG. 7 is a flowchart for explaining the control in the refrigerant shortage detection mode. The refrigerant shortage detection mode is periodically executed by a timer or the like, for example, once a day or several days.

When the refrigerant shortage detection mode is set, in step S11, the control device 100 sets the operating frequency of the compressor 10 to a predetermined fixed frequency. In the configuration having the injection flow path as in the second embodiment, the opening degree of the expansion valve of the injection flow path is also fixed.

Subsequently, in step S12, the control device 100 sets the rotation speed of the fan 22 to be equal to or lower than the minimum rotation speed that can be obtained in normal operation. For example, the rotation of the fan 22 may be stopped. As a result, the efficiency of heat exchange with the outside air in the condenser 20 is lowered, and the refrigerant is less likely to condense in the condenser 20. Then, the dryness of the outlet portion of the receiver 30 provided with the gas-liquid separation mechanism increases as compared with the normal operation. That is, the ratio of gas refrigerant in the refrigerant increases as compared with the case of normal operation.

Subsequently, in step S13, the control device 100 detects whether or not the refrigerant is insufficient based on the presence or absence of the superheat degree SH at the outlet (point C) of the refrigerant heating device.

FIG. 8 is a diagram showing the relationship between the rotation speed of the fan, the amount of the refrigerant, and the dryness of the refrigerant. Here, the amount of refrigerant 100% indicates a specified filling amount that is not excessive or deficient in design, and the difference from 100% is assumed to be the insufficient amount. At the beginning of installation, there is a margin in the filling amount, so for example, the amount of refrigerant may be 110%. Then, when the amount of refrigerant leaks and the amount of refrigerant decreases to less than 100%, it is determined that the refrigerant is insufficient.

The degree of dryness that allows gas-liquid separation is a value determined by the design of the gas-liquid separation mechanism. Assuming that the dryness of the gas-liquid separable limit is 0.05, FIG. 8 shows that when the amount of refrigerant is 95%, gas-liquid separation cannot be performed when the fan speed is reduced to 25%. When the amount of refrigerant is 85%, the fan rotation speed drops to 40%, and when the amount of refrigerant is 80%, the gas-liquid separation becomes impossible when the fan speed drops to 60%.

Therefore, for example, in step S13, the control device 100 reduces the fan speed to 25%, and the refrigerant heating device 75 heats the refrigerant. At this time, the control device 100 obtains the saturation temperature T0 corresponding to the pressure PL from the conversion table stored in advance, calculates the difference from the temperature T1 actually measured by the temperature sensor 122, and superheats SH (= T1). -T0) is calculated. Then, if the superheat degree SH> 0, it is determined that the refrigerant is insufficient, and if the superheat degree SH = 0, it is determined that the amount of the refrigerant is equal to or more than the specified amount.

If there is no refrigerant shortage (NO in S13), the refrigerant shortage detection mode ends, and the control during normal operation shown in FIG. 6 is executed.

On the other hand, when the refrigerant is insufficient (YES in S13), in the present embodiment, the control device 100 further detects the amount of the refrigerant in step S14, and the user determines the degree of the shortage in step S15. Notify to. The control device 100 causes the notification device 101 to output an alarm indicating that the refrigerant is insufficient. The notification device 101 is, for example, a display device such as a liquid crystal display, a warning lamp, or the like, and may be a device that transmits a warning signal to an external device via a communication line.

In steps S11 to S13 described above, the control device 100 increases the dryness of the outlet of the condenser 20 and increases the circulation amount of the refrigerant in the main circuit so that the refrigerant shortage can be detected at an early stage. The superheat degree SH of the point C is confirmed after setting the state close to the sky. By operating under stricter conditions than normal operating conditions, it becomes easier to determine the refrigerant shortage based on the degree of superheat SH.

Then, in step S14, it is investigated to what extent the amount of refrigerant has decreased, which is useful for maintenance and inspection of the refrigeration cycle device. Based on the result of the notification, the user can consider whether or not to stop the refrigerating cycle device, when to repair the refrigerant leak, or when to fill the refrigerant shortage. The control device 100 may notify the user or the service provider of the urgency or the additional encapsulation amount based on the detected shortage amount.

FIG. 9 is a flowchart showing details of the process (S14) for detecting the amount of refrigerant. First, in step S21, the control device 100 gradually increases the rotation speed of the fan 22 while heating the refrigerant by the refrigerant heating device 75 (for example, a heater). Then, in step S22, the fan rotation speed at which the superheat degree SH of the refrigerant at the point C becomes zero is specified. Then, in step S23, the control device 100 detects the amount of refrigerant from the map showing the correspondence between the fan rotation speed and the amount of refrigerant stored in advance.

FIG. 10 is an example of a map for obtaining the amount of refrigerant from the rotation speed of the fan. When the graph shown in FIG. 8 is modified and the vertical axis represents the amount of refrigerant, the graph of FIG. 10 is obtained. Here, assuming that the boundary of gas-liquid separation availability of the gas-liquid separation mechanism arranged at the branch point BP1 is a dryness of 0.05, the line of the dryness of 0.05 in FIG. 10 is the line between the fan rotation speed and the amount of refrigerant. It will be a map showing the correspondence. The region above the line with a dryness of 0.05 is the region where the amount of refrigerant is equal to or greater than the appropriate amount, and the region below is the region where the amount of refrigerant is insufficient. For example, in step S12 of FIG. 7, it is assumed that the fan rotation speed is reduced to 25% corresponding to the refrigerant amount of 95% and it is investigated whether or not the refrigerant is insufficient. When it is determined that the refrigerant is insufficient, the fan rotation speed is gradually increased from 25% to detect the amount of refrigerant.

For example, if the superheat degree SH changes from SH> 0 to SH = 0 when the fan rotation speed reaches 30%, it can be detected that the amount of refrigerant is 90%. Similarly, if the superheat degree SH changes from SH> 0 to SH = 0 when the fan rotation speed reaches 40%, it can be detected that the amount of refrigerant is 85%. Similarly, if the superheat degree SH changes from SH> 0 to SH = 0 when the fan rotation speed reaches 60%, it can be detected that the amount of refrigerant is 80%.

In the above-described example, the amount of refrigerant is detected by changing the dryness of the refrigerant by changing the rotation speed of the fan 22, but the rotation speed of the fan 22 is fixed at 30% and the compressor is operated instead. The amount of refrigerant may be detected by changing the frequency and changing the dryness.

FIG. 11 is an example of a map for obtaining the amount of refrigerant from the frequency of the compressor. The vertical axis indicates the amount of refrigerant (%), and the horizontal axis indicates the operating frequency (Hz). Considering the same as the description of FIG. 10, assuming that the boundary of gas-liquid separation availability of the gas-liquid separation mechanism arranged at the branch point BP1 is a dryness of 0.05, the line of the dryness of 0.05 in FIG. 11 is compressed. It is a map showing the correspondence between the operating frequency of the machine and the amount of refrigerant. The upper region of the line having a dryness of 0.05 is a region where the amount of refrigerant is equal to or more than an appropriate amount, and the lower region is a region where the amount of refrigerant is insufficient.

For example, the rotation speed of the fan 22 is set to 30% and the operating frequency of the compressor is set to 80 Hz to determine whether or not the refrigerant is insufficient. If the refrigerant is insufficient, the operating frequency of the compressor is gradually lowered from 80 Hz. , Check the operating frequency of the compressor where the superheat degree SH becomes zero. For example, when the operating frequency at this time is 70 Hz, it can be detected that the amount of refrigerant is 85%, and when the operating frequency is 30 Hz, it can be detected that the amount of refrigerant is 77.5%.

As described above, in the first embodiment, the fan rotation speed is first set to be lower or zero than in the normal operation, so that the capacity of the condenser 20 is lowered and the dryness of the refrigerant passing through the condenser is high. Make it easier to detect refrigerant shortage. This makes it possible to detect the refrigerant shortage even at an early stage of the refrigerant shortage. Further, when the refrigerant is insufficient, the dryness of the refrigerant passing through the condenser can be gradually reduced by a fan or the like, and the amount of the refrigerant can be detected. Thereby, it is possible to inform the user or the service provider of the urgency or the additional filling amount from the detected amount of the refrigerant.

Embodiment 2.
In the first embodiment, as a means for increasing the dryness of the gas-liquid separation portion, the fan rotation speed is decreased or the compressor frequency is increased, but when the injection flow path and the internal heat exchanger are provided, the injection flow path is expanded. The opening degree of the valve may be increased, or these may be combined.

FIG. 12 is a diagram showing the configuration of the refrigeration cycle device 201 according to the second embodiment. The refrigeration cycle device 201 includes an outdoor unit 202 instead of the outdoor unit 2 in the configuration of the refrigeration cycle device 1 shown in FIG. Since the configuration of the load device 3 is the same, the description will not be repeated.

In the configuration of the outdoor unit 2, the outdoor unit 202 includes a compressor 210 and a control device 300 instead of the compressor 10 and the control device 100, and further includes a heat exchanger 40, an expansion valve 92, and pipes 93 and 94. To be equipped. Since the configuration of other parts of the outdoor unit 202 is the same as that of the outdoor unit 2, the description will not be repeated.

The heat exchanger 40 has a first passage H1 and a second passage H2, and is configured to exchange heat between the refrigerant flowing through the first passage H1 and the refrigerant flowing through the second passage H2. The liquid receiver 30 is arranged between the first passage H1 of the heat exchanger 40 and the condenser 20, and is configured to store the refrigerant.

The compressor 210 has an intermediate pressure port G3 in addition to the suction port G1 and the discharge port G2. The compressor 210 is configured to suck the refrigerant that has passed through the evaporator 60 from the suction port G1 and discharge the refrigerant from the discharge port G2 toward the condenser 20 together with the refrigerant sucked from the intermediate pressure port G3. To.

The expansion valve 92, the pipe 93, the second passage H2 of the heat exchanger 40, and the pipe 94 constitute a third passage F3 for flowing the refrigerant from the branch point BP2 of the main circuit to the intermediate pressure port G3 of the compressor 210. The third flow path F3 is also referred to as an "injection flow path".

In the example described in the first embodiment, the dryness of the refrigerant is changed to detect the amount of the refrigerant by changing the rotation speed of the fan 22, but in the second embodiment, the rotation speed of the fan 22 and the compressor are detected. The operating frequency of the expansion valve 92 is fixed, and instead, the opening degree of the expansion valve 92 is changed to change the dryness.

FIG. 13 is an example of a map for obtaining the amount of refrigerant from the opening degree of the expansion valve. The vertical axis represents the amount of refrigerant (%), and the horizontal axis represents the number of pulses of the control signal corresponding to the opening degree of the expansion valve 92. The larger the number of pulses, the larger the opening degree of the expansion valve 92. Hereinafter, the opening degree of the expansion valve is represented by the number of pulses. Assuming that the boundary of gas-liquid separation availability of the gas-liquid separation mechanism arranged at the branch point BP1 is 0.05 dryness as in the description of FIGS. 10 and 11, the line of dryness 0.05 in FIG. 13 is compressed. It is a map showing the correspondence between the operating frequency of the machine and the amount of refrigerant. The region above the line with a dryness of 0.05 is the region where the amount of refrigerant is equal to or greater than the appropriate amount, and the region below is the region where the amount of refrigerant is insufficient.

For example, the rotation speed of the fan 22 is set to 30% and the opening degree of the expansion valve 92 is set to 60 pulses to determine whether or not the refrigerant is insufficient. If the refrigerant is insufficient, the opening degree of the expansion valve 92 is gradually reduced. Then, the opening degree of the expansion valve 92 at which the superheat degree SH becomes zero is examined. For example, if the opening degree of the expansion valve 92 at this time is 50 pulses, it can be detected that the amount of refrigerant is 77%, and if the opening degree of the expansion valve 92 is 30 pulses, the amount of refrigerant is It can be detected as 74.5%.

Also in the second embodiment, in order to change the dryness of the refrigerant when detecting the amount of the refrigerant, either the rotation speed of the fan 22 or the operating frequency of the compressor 210 is changed by changing the opening degree of the expansion valve 92. It may be used in combination with the change of.

Finally, the first and second embodiments will be summarized with reference to the drawings again. With reference to FIG. 1, the outdoor unit 2 of the refrigeration cycle device 1 has a normal mode and a refrigerant shortage detection mode, and is configured to be connected to a load device 3 including an expansion device 50 and an evaporator 60. .. The outdoor unit 2 includes a first flow path F1, a compressor 10, a condenser 20, a second flow path F2, a riser pipe 71 having a gas-liquid separation structure, a flow rate adjusting device 73, and a refrigerant heating device. It includes 75, a dryness increasing device 150, a temperature sensor 122, and a notification device 101.

The first flow path F1 is connected to the load device 3 to form a circulation flow path through which the refrigerant circulates. The compressor 10 and the condenser 20 are arranged in the first flow path F1. The second flow path F2 is configured to branch from the branch point BP1 of the first flow path F1 downstream of the condenser 20 in the direction in which the refrigerant circulates, and return the refrigerant that has passed through the condenser 20 to the compressor 10. Will be done. The riser pipe 71, which has a gas-liquid separation structure, is provided at the branch point BP1. The flow rate adjusting device 73 and the refrigerant heating device 75 are arranged in the second flow path F2 in order from the branch point BP1. The dryness increasing device 150 increases the dryness of the refrigerant after passing through the condenser 20 in the refrigerant shortage detection mode as compared with the normal mode. The temperature sensor 122 detects the temperature T1 of the refrigerant that has passed through the refrigerant heating device 75 of the second flow path F2. In the refrigerant shortage detection mode, the notification device 101 notifies that the refrigerant is insufficient according to the output of the temperature sensor 122.

Preferably, the dryness increasing device 150 includes a fan 22 configured to send outside air to the condenser 20 and a control device 100 for controlling the fan 22. As shown in step S12 of FIG. 7, in the refrigerant shortage detection mode, the rotation speed of the fan 22 is set to a rotation speed lower than that of the normal mode or zero.

More preferably, the notification device 101 notifies the amount of refrigerant corresponding to the rotation speed of the fan 22 in which the superheat degree SH calculated based on the output of the temperature sensor 122 changes from positive to zero in the refrigerant shortage detection mode. (Steps S14 and S15 in FIG. 7).

More preferably, in the refrigerant shortage detection mode, the notification device 101 notifies the amount of refrigerant corresponding to the operating frequency of the compressor 10 in which the superheat degree SH calculated based on the output of the temperature sensor 122 changes from positive to zero. It is configured as follows.

Preferably, as shown in FIG. 12, the outdoor unit 202 has a first passage H1 and a second passage H2, and exchanges heat between the refrigerant flowing through the first passage H1 and the refrigerant flowing through the second passage H2. It further comprises a heat exchanger 40 configured to do so and an expansion valve 92. The first passage H1 of the heat exchanger 40 is arranged downstream of the condenser 20 of the first passage F1. The compressor 210 has an intermediate pressure port G3 in addition to the suction port G1 and the discharge port G2. The compressor 210 is configured to suck the refrigerant that has passed through the evaporator 60 from the suction port G1 and discharge the refrigerant from the discharge port G2 toward the condenser 20 together with the refrigerant sucked from the intermediate pressure port G3. To.

The outdoor unit 202 further includes a third flow path F3 for flowing a refrigerant from the branch point BP2 of the main circuit to the intermediate pressure port G3 of the compressor 210. The third flow path F3 includes an expansion valve 92, a pipe 93, a second passage H2 of the heat exchanger 40, and a pipe 94.

The notification device 101 is configured to notify the amount of refrigerant corresponding to the opening degree of the expansion valve 92 in which the superheat degree SH calculated based on the output of the temperature sensor 122 changes from positive to zero in the refrigerant shortage detection mode. To.

Preferably, as shown in FIGS. 2 and 3, the second flow path F2 branches from the first flow path F1 in the direction opposite to gravity in the riser pipe 71 at the branch point BP1.

Although the present embodiment has been described above by exemplifying a refrigerator provided with the refrigerating cycle device 1, the refrigerating cycle device 1 may be used as an air conditioner or the like.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

1,201 Refrigeration cycle device, 2,202 outdoor unit, 3 load device, 10,210 compressor, 20 condenser, 22 fan, 30 receiver, 40 heat exchanger, 50 expansion device, 60 evaporator, 71 standing Raising pipe, 72,74,80,81,82,83,85,86,87,89,93,94 pipe, 73 flow control device, 75 refrigerant heating device, 84,88 extension pipe, 92 expansion valve, 100, 300 control device, 101 notification device, 104 memory, 110,111 pressure sensor, 120,121,122 temperature sensor, 150 dryness increasing device, BP1, BP2 branch point, F1, F2, F3 flow path, G1 suction port, G2 Discharge port, G3 intermediate pressure port, H1 first passage, H2 second passage.

Claims (7)

An outdoor unit of a refrigeration cycle device having a normal mode and a refrigerant shortage detection mode and configured to be connected to a load device including an expansion device and an evaporator.
A first flow path that forms a circulation flow path through which the refrigerant circulates by being connected to the load device, and
A compressor and a condenser arranged in the first flow path,
In the direction in which the refrigerant circulates, the second flow path is configured to branch from the branch point of the first flow path downstream of the condenser and return the refrigerant that has passed through the condenser to the compressor. ,
The gas-liquid separation structure provided at the branch point and
A flow rate adjusting device and a refrigerant heating device arranged in the second flow path in order from the branch point,
A dryness increasing device that increases the dryness of the refrigerant after passing through the condenser in the refrigerant shortage detection mode as compared with the normal mode.
A temperature sensor that detects the temperature of the refrigerant that has passed through the refrigerant heating device in the second flow path, and
An outdoor unit including a notification device that notifies that a refrigerant is insufficient according to an output of the temperature sensor in the refrigerant shortage detection mode. The dryness increasing device comprises a fan configured to send outside air to the condenser.
The outdoor unit according to claim 1, wherein in the refrigerant shortage detection mode, the rotation speed of the fan is set to a rotation speed lower than that of the normal mode or zero. According to claim 2, the notification device notifies the amount of refrigerant corresponding to the rotation speed of the fan whose degree of superheat calculated based on the output of the temperature sensor changes from positive to zero in the refrigerant shortage detection mode. The listed outdoor unit. 2. The notification device notifies the amount of refrigerant corresponding to the operating frequency of the compressor in which the degree of superheat calculated based on the output of the temperature sensor changes from positive to zero in the refrigerant shortage detection mode. The outdoor unit described in. A heat exchanger having a first passage and a second passage and configured to exchange heat between the refrigerant flowing through the first passage and the refrigerant flowing through the second passage.
Expansion valve and
Further equipped with a third flow path
The first passage of the heat exchanger is arranged downstream of the condenser of the first passage.
The compressor has an intermediate pressure port in addition to the suction port and the discharge port.
The compressor is configured to suck the refrigerant that has passed through the evaporator from the suction port, combine it with the refrigerant sucked from the intermediate pressure port, and discharge the refrigerant from the discharge port toward the condenser. ,
The third passage includes the expansion valve and the second passage of the heat exchanger.
The third flow path is configured to allow refrigerant to flow from the first flow path to the intermediate pressure port of the compressor.
2. The notification device notifies the amount of refrigerant corresponding to the opening degree of the expansion valve in which the degree of superheat calculated based on the output of the temperature sensor changes from positive to zero in the refrigerant shortage detection mode. The outdoor unit described in. The outdoor unit according to claim 1, wherein the second flow path branches from the first flow path in the direction opposite to gravity in the gas-liquid separation structure at the branch point. A refrigeration cycle device including the outdoor unit according to any one of claims 1 to 6 and the load device.

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