JP7282207B2 - Outdoor unit and refrigeration cycle equipment - Google Patents

Description

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

In International Publication No. 2016/135904, the refrigerant filled in the refrigerant circuit is used as a 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 refrigeration system is disclosed that includes a refrigerant amount determination unit that determines the amount of refrigerant.

WO2016/135904

In the method described in International Publication No. WO 2016/135904, there are cases where the decrease in the amount of refrigerant cannot be detected from the time when the amount of refrigerant starts to decrease to the state where the shortage of refrigerant actually progresses.

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

The present disclosure relates to an outdoor unit of a refrigeration cycle apparatus 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 includes a first flow path forming a circulation flow path in which the refrigerant circulates by being connected to a load device, a compressor and a condenser arranged in the first flow path, and a direction in which the refrigerant circulates. , a second flow path branched from a branch point of the first flow path downstream of the condenser and configured to return the refrigerant that has passed through the condenser to the compressor; and a gas-liquid separation structure provided at the branch point. , a flow rate adjusting device and a refrigerant heating device arranged in the second flow path in order from the branch point, and a dryness that increases the dryness of the refrigerant after passing through the condenser in the refrigerant shortage detection mode compared to 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 a notification device that notifies the refrigerant shortage 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 in which the dryness of the refrigerant flowing through the bypass channel is increased more than during normal operation, refrigerant shortage can be detected at an early stage.

1 is a diagram showing a configuration of a refrigeration cycle apparatus 1 according to 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. FIG. 3 is a Mollier diagram showing a refrigeration cycle when the amount of refrigerant is appropriate; FIG. 4 is a Mollier diagram showing a refrigeration cycle when the amount of refrigerant is insufficient. 5 is a flowchart for explaining control of the rotation speed of the fan during normal operation; 4 is a flowchart for explaining control in a refrigerant shortage detection mode; FIG. 4 is a diagram showing the relationship between the rotational speed of the fan, the amount of refrigerant, and the dryness of the refrigerant; It is a flowchart which shows the detail of the process (S14) which detects refrigerant|coolant amount. It is an example of a map for obtaining the amount of refrigerant from the rotation speed of the fan. It is an example of a map for obtaining the amount of refrigerant from the frequency of the compressor. FIG. 3 is a diagram showing the configuration of a refrigeration cycle device 201 according to Embodiment 2; It is an example of a map for obtaining the amount of refrigerant from the degree of opening of the expansion valve.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention 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 a diagram showing the configuration of a refrigeration cycle apparatus 1 according to Embodiment 1. FIG. Referring to FIG. 1 , 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 80-83 and 89. The liquid receiver 30 is arranged between the pipe 82 and the condenser 20 and configured to store the refrigerant.

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

Load device 3 includes expansion device 50 , evaporator 60 , and pipes 85 , 86 , 87 . The expansion device 50 is, for example, a temperature expansion valve 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 an intake port G1 and a discharge port G2. Compressor 10 is configured to suck the refrigerant that has passed through evaporator 60 through suction port G1 and to discharge the refrigerant toward condenser 20 through discharge port G2.

The outdoor unit 2 further includes a rising pipe 71 , a pipe 72 , a flow rate adjusting device 73 , a pipe 74 and a refrigerant heating device 75 . The pipe 72 branches off from a 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 control device 73 . A pipe 74 connects one end of the flow control device 73 and the pipe 89 . The refrigerant heating device 75 is configured to heat the refrigerant that has passed through the flow rate adjusting device 73 . An electric heater, for example, can be used as the refrigerant heating device 75 . As the flow rate adjusting device 73, for example, a capillary tube can be typically used, but any device such as an orifice that narrows the cross-sectional area of the flow path and causes a pressure difference may be used. Also, an expansion valve may be used as the flow control device 73 . Hereinafter, this second flow path F2 that branches off from the main circuit and sends the refrigerant to the compressor 10 via the flow control device 73 is called a "bypass flow path".

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

Due to the branching by the rising pipe 71 , two-phase refrigerant mixed with gas refrigerant is introduced into the pipe 72 when the refrigerant leaks and the refrigerant becomes insufficient.

If the compressor has an intermediate pressure port, the connection destination of the bypass passage may be the intermediate pressure port instead of the intake port of the compressor 10 .

Compressor 10 is configured to adjust its rotational 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 refrigerating capacity of the refrigerating 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 discharged from the compressor 10 to the pipe 80 and flows it to the pipe 81 . Condenser 20 is configured such that the high-temperature, high-pressure gas refrigerant discharged from compressor 10 exchanges heat with the outside air. Due to this heat exchange, the heat-dissipated refrigerant condenses and changes 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 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 controller 100 that controls the outdoor unit 2 .

Pressure sensor 110 detects pressure PL of the refrigerant drawn into compressor 10 and outputs the detected value to control device 100 . Pressure sensor 111 detects pressure PH of refrigerant discharged from compressor 10 and outputs the detected value to control device 100 . Temperature sensor 120 detects the temperature TA of the outside air sent to condenser 20 and outputs the detected value to control device 100 . Temperature sensor 121 detects temperature TC of refrigerant in pipe 81 at the outlet of condenser 20 and outputs the detected value to control device 100 . The temperature sensor 122 detects the temperature T<b>1 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 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.

As described above, in Embodiment 1, a bypass flow path is provided from the outlet of the liquid receiver 30, which is the high pressure section, to the suction section of the compressor 10, which is the low pressure section. A flow rate adjusting device 73 and a refrigerant heating device 75 are arranged in the bypass channel. A temperature sensor 122 and a pressure sensor 110 for detecting the low-pressure saturation temperature are provided at a portion passing through the refrigerant heating device 75 . In addition, the low-pressure saturation temperature may be measured by measuring the outlet temperature of the flow rate adjusting device 73 .

In such a configuration, a gas-liquid separation mechanism is provided at the branch point BP1 of the bypass channel. FIG. 2 is a diagram for explaining a state in which gas-liquid separation cannot be performed 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.

Referring to FIGS. 2 and 3, the gas-liquid separation mechanism is constituted by a riser pipe 71 rising from a pipe 82, which is a liquid pipe, in the direction opposite to gravity.

As shown in FIG. 2, when the dryness of the refrigerant flowing through the pipe 82 is low, a two-phase refrigerant in which liquid refrigerant and gas refrigerant are mixed flows through the riser pipes 71 and 72 . On the other hand, as shown in FIG. 3 , if the dryness of the refrigerant flowing through the pipe 82 is high, the liquid refrigerant will drop due to gravity in the middle of the rising pipe 71 , and the liquid refrigerant will flow into the pipe 72 via the rising pipe 71 . Separated single-phase gaseous refrigerant flows.

When a two-phase refrigerant flows through the bypass flow path, heat is absorbed as latent heat for evaporating the refrigerant even if it is heated by the refrigerant heating device 75 . Therefore, temperature T1 detected by temperature sensor 122 matches the saturation temperature of the refrigerant. In this state, the degree of superheat SH of the refrigerant is zero.

On the other hand, when a gaseous refrigerant is flowing through the bypass channel, heat is absorbed by the refrigerant as sensible heat when heated by the refrigerant heating device 75, so 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 SH>0 of the refrigerant.

FIG. 4 is a Mollier diagram showing a refrigeration cycle when the amount of refrigerant is appropriate. Points A, B, and C in FIG. 4 correspond to points A, B, and C entered in FIG. Since liquid refrigerant and gas refrigerant normally exist in the liquid receiver 30, the state of the refrigerant at the outlet of the liquid receiver 30 is on the saturated liquid line as indicated by point A in FIG. That is, the inlet of the bypass channel becomes liquid (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 control device 73, the state of the refrigerant changes from point A to point B. As shown in FIG. When the refrigerant is heated by the refrigerant heating device 75, the state of the refrigerant changes from point B to point C. As shown in FIG.

At this time, since a large amount of liquid refrigerant flows through the pipe 74, even if the point moves rightward due to heating, it does not exceed the saturated gas line, so the temperature of the refrigerant remains at the saturation temperature.

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

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

At this time, no liquid refrigerant is flowing through the pipe 74, so if the point moves rightward due to heating, the saturated gas line will be crossed. 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 it can be determined that the refrigerant is insufficient.

For the two-phase refrigerant, if the pressure is measured with a pressure sensor, the corresponding temperature (saturation temperature) is determined. A conversion table indicating the correspondence between the pressure and the saturation temperature is stored in advance in the memory 104 of the control device 100 . 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. If the saturation temperature is T0, the degree of superheat SH is SH=T1-T0.

FIG. 6 is a flow chart for explaining control of the rotational 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, it is set so that the difference between the temperature TC, which is the condensing temperature, and the outside air is 10°C.

First, in step S<b>1 , 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 heat exchange in the condenser 20 is efficient, and is 10°C, for example. Subsequently, in step S2, the temperature sensor 121 measures the condensation temperature TC and compares the measured condensation temperature TC with the target temperature. If TC>target temperature (YES in S2), control device 100 increases the rotational speed of fan 22 in step S3 to lower temperature TC. On the other hand, if TC<target temperature (YES in S4), control device 100 reduces the rotation speed of fan 22 in step S5 to increase condensation temperature TC. If condensing temperature TC matches the target temperature (NO in S2 and NO in S4), control device 100 maintains the current rotational speed of fan 22 without changing it. In order to avoid frequent changes in the rotation speed of the fan 22, a difference may be provided between the target temperatures in steps S2 and S4 to provide hysteresis.

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

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

Also, when using multiple indoor units, if there is an indoor unit that is stopped, the refrigerant will be stored in the liquid receiver, so the receiver will only receive when all the indoor units are operating. The amount of liquid in the liquid container is reduced.

Therefore, in order to detect the shortage of refrigerant at an early stage, in the refrigerant shortage detection mode, in the present embodiment, the dryness of the liquid receiver outlet portion provided with the gas-liquid separation mechanism is controlled during normal operation. The refrigerant shortage detection part provided in the bypass passage is made easier to detect the shortage of the refrigerant.

FIG. 7 is a flowchart for explaining 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 addition, in a configuration having an injection passage as in the second embodiment, the opening degree of the expansion valve of the injection passage is also fixed.

Subsequently, in step S12, the control device 100 sets the rotational speed of the fan 22 to be equal to or lower than the lowest possible rotational speed in normal operation. For example, the rotation of 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 . As a result, the dryness at the outlet of the liquid receiver 30 where the gas-liquid separation mechanism is provided is higher than during normal operation. That is, the gas refrigerant ratio in the refrigerant increases compared to that during 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 degree of superheat SH at the outlet (point C) of the refrigerant heating device.

FIG. 8 is a diagram showing the relationship between the rotational speed of the fan, the amount of refrigerant, and the dryness of the refrigerant. Here, the refrigerant amount of 100% indicates a specified charging amount that is neither excessive nor insufficient in terms of design, and the difference from 100% is the insufficient amount. At the beginning of installation, there is a margin in the charging amount, so the refrigerant amount may be 110%, for example. Then, when the amount of refrigerant decreases due to leakage and becomes less than 100%, it is determined that the refrigerant is insufficient.

The dryness at which gas-liquid separation is possible is a value determined by the design of the gas-liquid separation mechanism. Assuming that the limit dryness for gas-liquid separation is 0.05, FIG. 8 shows that when the amount of refrigerant is 95%, gas-liquid separation becomes impossible when the fan speed is reduced to 25%. When the amount of refrigerant is 85%, the fan speed is 40%.

Therefore, for example, in step S<b>13 , control device 100 reduces the fan speed to 25% and heats the refrigerant by refrigerant heating device 75 . At this time, the controller 100 obtains the saturation temperature T0 corresponding to the pressure PL from a prestored conversion table, calculates the difference from the temperature T1 actually measured by the temperature sensor 122, and calculates the degree of superheat SH (=T1 −T0) is calculated. If the degree of superheat SH>0, it is determined that the refrigerant is insufficient, and if the degree of superheat SH=0, it is determined that the amount of refrigerant is greater than or equal to 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, if there is a shortage of refrigerant (YES in S13), in the present embodiment, control device 100 further detects the amount of refrigerant in step S14, and in step S15 the degree of shortage is determined by the user. to be notified. 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, increases the amount of refrigerant circulating in the main circuit, and increases the amount of refrigerant circulating in the main circuit so that the lack of refrigerant can be detected at an early stage. is almost empty, and then the superheat SH at point C is checked. By operating under conditions severer than normal use conditions, the shortage of refrigerant can be easily judged from the degree of superheat SH.

Then, in step S14, it is checked 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 to stop the refrigeration cycle device, when to repair the leakage of the refrigerant or when to charge the insufficient amount of refrigerant. The control device 100 may notify the user or the service provider of the urgency and the additional amount to be enclosed based on the detected shortage amount.

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

FIG. 10 is an example of a map for obtaining the amount of refrigerant from the rotation speed of the fan. If the graph shown in FIG. 8 is modified and the vertical axis is the amount of refrigerant, the graph of FIG. 10 is obtained. Here, assuming that the dryness of the gas-liquid separation mechanism arranged at the branch point BP1 is 0.05, the line of the dryness of 0.05 indicates the relationship between the fan rotation speed and the amount of refrigerant. It becomes a map showing correspondence. The area above the line of dryness 0.05 is the area where the amount of refrigerant is more than the appropriate amount, and the area below is the area 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 checked whether there is a shortage of refrigerant. Then, 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 degree of superheat SH changes from SH>0 to SH=0 when the fan rotation speed reaches 30%, it can be detected that the refrigerant amount is 90%. Similarly, if the degree of superheat SH changes from SH>0 to SH=0 when the fan rotation speed reaches 40%, it can be detected that the refrigerant amount is 85%. Similarly, if the degree of superheat SH changes from SH>0 to SH=0 when the fan rotation speed reaches 60%, it can be detected that the refrigerant amount is 80%.

In the example described above, by changing the rotation speed of the fan 22, the dryness of the refrigerant is changed and the amount of refrigerant is detected. The amount of refrigerant may be detected by changing the dryness by changing the frequency.

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 explanation of FIG. 10, if the boundary of the gas-liquid separation possibility of the gas-liquid separation mechanism arranged at the branch point BP1 is 0.05 of dryness, the line of 0.05 of dryness 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 area above the line of dryness 0.05 is the area where the amount of refrigerant is more than the appropriate amount, and the area below is the area 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. , the operating frequency of the compressor at which the degree of superheat SH becomes zero. For example, if the operating frequency at this time is 70 Hz, the refrigerant amount can be detected as 85%, and if the operating frequency is 30 Hz, the refrigerant amount can be detected as 77.5%.

As described above, in the first embodiment, first, the fan rotation speed is set to be lower than that during normal operation or to zero, thereby lowering the capacity of the condenser 20 and creating a state in which the dryness of the refrigerant passing through the condenser is high. To make it easier to detect a refrigerant shortage. This makes it possible to detect a refrigerant shortage even at an early stage of the refrigerant shortage. Furthermore, when the refrigerant is insufficient, the dryness of the refrigerant passing through the condenser is gradually reduced by a fan or the like, and the amount of refrigerant can be detected. This makes it possible to notify the user or the service provider of the urgency or the amount of additional charging from the detected amount of refrigerant.

Embodiment 2.
In Embodiment 1, as means for increasing the dryness of the gas-liquid separation section, the fan rotation speed is lowered or the compressor frequency is increased. The opening degree of the valve may be increased, or a combination of these may be used.

FIG. 12 is a diagram showing the configuration of a refrigeration cycle device 201 according to Embodiment 2. As shown in FIG. A refrigerating cycle device 201 includes an outdoor unit 202 in place of the outdoor unit 2 in the configuration of the refrigerating cycle device 1 shown in FIG. Since the configuration of the load device 3 is the same, the description will not be repeated.

The outdoor unit 202 includes a compressor 210 and a control device 300 instead of the compressor 10 and the control device 100 in the configuration of the outdoor unit 2, and further includes a heat exchanger 40, an expansion valve 92, and pipes 93 and 94. Prepare. The configuration of other parts of the outdoor unit 202 is the same as that of the outdoor unit 2, so 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 refrigerant.

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

The expansion valve 92 , the pipe 93 , the second passage H<b>2 of the heat exchanger 40 and the pipe 94 constitute a third flow path F<b>3 through which the refrigerant flows from the branch point BP<b>2 of the main circuit to the intermediate pressure port G<b>3 of the compressor 210 . The third flow path F3 is also called an "injection flow path".

In the example described in the first embodiment, the amount of refrigerant is detected by changing the dryness 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 is fixed, and instead the degree of opening of the expansion valve 92 is changed to change the degree of dryness.

FIG. 13 is an example of a map for obtaining the amount of refrigerant from the degree of opening of the expansion valve. The vertical axis indicates the amount of refrigerant (%), and the horizontal axis indicates the number of pulses of the control signal corresponding to the degree of opening of the expansion valve 92 . As the number of pulses increases, the opening of the expansion valve 92 increases. Hereinafter, the opening degree of the expansion valve is represented by the number of pulses. As in the description of FIGS. 10 and 11, if the dryness of the gas-liquid separation mechanism arranged at the branch point BP1 is 0.05, the line of dryness of 0.05 is compressed. It is a map showing the correspondence between the operating frequency of the machine and the amount of refrigerant. The area above the line of dryness 0.05 is the area where the amount of refrigerant is more than the appropriate amount, and the area below is the area where the amount of refrigerant is insufficient.

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

In the second embodiment as well, in order to change the dryness of the refrigerant when detecting the amount of refrigerant, the change in either the rotational speed of the fan 22 or the operating frequency of the compressor 210 is controlled by the opening degree of the expansion valve 92. may be used in combination with the modification of

Finally, Embodiments 1 and 2 will be summarized with reference to the drawings again. Referring to FIG. 1, an outdoor unit 2 of a 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 rising pipe 71 having a gas-liquid separation structure, a flow rate adjusting device 73, and a refrigerant heating device. 75 , dryness increasing device 150 , temperature sensor 122 , and notification device 101 .

The first flow path F1 is connected to the load device 3 to form a circulation flow path through which the coolant circulates. Compressor 10 and condenser 20 are arranged in first flow path F1. The second flow path F2 branches from a branch point BP1 of the first flow path F1 downstream of the condenser 20 in the direction in which the refrigerant circulates, and is configured to return the refrigerant that has passed through the condenser 20 to the compressor 10. be done. A rising pipe 71, which is a gas-liquid separation structure, is provided at the branch point BP1. The flow regulating 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 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 in 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 intensifying device 150 comprises a fan 22 configured to send ambient air to the condenser 20 and a controller 100 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 in the normal mode or zero.

More preferably, in the refrigerant shortage detection mode, the notification device 101 notifies the amount of refrigerant corresponding to the rotation speed of the fan 22 at which the degree of superheat SH calculated based on the output of the temperature sensor 122 changes from positive to zero. (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 at which the degree of superheat SH calculated based on the output of the temperature sensor 122 changes from positive to zero. configured as

Preferably, as shown in FIG. 12, the outdoor unit 202 has a first passage H1 and a second passage H2, and heat exchange is performed 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 in the first flow path F1. The compressor 210 has an intermediate pressure port G3 in addition to a suction port G1 and a discharge port G2. The compressor 210 is configured to suck the refrigerant that has passed through the evaporator 60 from the suction port G1, combine with the refrigerant sucked from the intermediate pressure port G3, and discharge the refrigerant from the discharge port G2 toward the condenser 20. be.

The outdoor unit 202 further includes a third flow path F3 that flows 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 includes an expansion valve 92, a pipe 93, a second passage H2 of the heat exchanger 40, and a pipe 94.

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

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

Although the refrigerator including the refrigerating cycle device 1 has been described above as an example, the refrigerating cycle device 1 may be used in an air conditioner or the like.

The embodiments disclosed this time should be considered as examples 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.

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 stand Raising piping, 72, 74, 80, 81, 82, 83, 85, 86, 87, 89, 93, 94 piping, 73 flow control device, 75 refrigerant heating device, 84, 88 extension piping, 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 forming a circulation flow path in which a coolant circulates by being connected to the load device;
a compressor and a condenser disposed in the first flow path;
a second flow path branched from a branch point of the first flow path downstream of the condenser in the direction in which the refrigerant circulates and configured to return the refrigerant that has passed through the condenser to the compressor; ,
a gas-liquid separation structure provided at the branch point;
a flow regulating 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 compared to 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 informing device that, in the refrigerant shortage detection mode, notifies that the refrigerant is insufficient according to the output of the temperature sensor. the dryness increasing device comprises a fan configured to send outside air to the condenser;
2. The outdoor unit according to claim 1, wherein in said refrigerant shortage detection mode, the rotation speed of said fan is set to a rotation speed lower than that in said normal mode or to zero. 3. The method according to claim 2, wherein in the refrigerant shortage detection mode, the notification device notifies an amount of refrigerant corresponding to a rotation speed of the fan at which the degree of superheat calculated based on the output of the temperature sensor changes from positive to zero. Outdoor unit as described. 3. The notifying device notifies, in the refrigerant shortage detection mode, the amount of refrigerant corresponding to the operating frequency of the compressor at which the degree of superheat calculated based on the output of the temperature sensor changes from positive to zero. The outdoor unit described in . a heat exchanger having a first passage and a second passage, configured to exchange heat between the refrigerant flowing through the first passage and the refrigerant flowing through the second passage;
an expansion valve;
further comprising a third flow path,
the first passage of the heat exchanger is arranged downstream of the condenser of the first flow path;
The compressor has an intermediate pressure port in addition to a suction port and a discharge port,
The compressor is configured to suck the refrigerant that has passed through the evaporator through the suction port, combine with the refrigerant sucked through the intermediate pressure port, and discharge the refrigerant through the discharge port toward the condenser. ,
the third passage comprises the expansion valve and the second passage of the heat exchanger;
the third flow path is configured to flow refrigerant from the first flow path to the intermediate pressure port of the compressor;
3. The notification device, in the refrigerant shortage detection mode, notifies the amount of refrigerant corresponding to the degree of opening of the expansion valve at which the degree of superheat calculated based on the output of the temperature sensor changes from positive to zero. The outdoor unit described in . 2. The outdoor unit according to claim 1, wherein said second flow path branches off from said first flow path in a direction opposite to gravity at said gas-liquid separation structure at said branch point. A refrigeration cycle apparatus comprising the outdoor unit according to any one of claims 1 to 6 and the load device.

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