JP7325542B2 - refrigeration cycle equipment - Google Patents

Description

The present disclosure relates to a refrigeration cycle device having a function of preventing liquid refrigerant (liquid refrigerant) from being sucked into a compressor.

Conventionally, a refrigeration cycle device having a function of preventing liquid refrigerant from being sucked into a compressor (liquid backflow) is known. For example, Japanese Patent Laying-Open No. 2010-19439 (Patent Document 1) discloses a refrigeration cycle device in which the refrigerant flowing into a refrigerant reservoir is switched according to the elapsed time from the startup of the compressor. In the refrigeration cycle device, when the compressor is started, the low-temperature and low-pressure gas-liquid two-phase refrigerant flows into the refrigerant reservoir via the low-pressure side flow switching means, and the separated gaseous refrigerant (gas refrigerant) flows into the refrigerant reservoir. is sucked into the compressor, and the separated liquid refrigerant is stored in the refrigerant reservoir.

JP 2010-19439 A

Depending on the stop time of the refrigeration cycle device, the gas refrigerant may be cooled and liquefied, so that a relatively large amount of liquid refrigerant is stored in the refrigerant container. If the compressor is started in this state, liquid backflow may occur. When liquid backflow occurs, the lubricating performance of the lubricating oil stored in the compressor decreases, increasing the possibility of the compressor breaking down. Also, depending on the amount of lubricating oil stored in the compressor, the performance of the compressor may deteriorate. However, in the refrigeration cycle device disclosed in Patent Document 1, reduction of the amount of liquid refrigerant in the refrigerant container at the time of starting the compressor and adjustment of the amount of lubricating oil during operation of the compressor are not taken into consideration.

The present disclosure has been made to solve the problems described above, and an object thereof is to improve the stability of a refrigeration cycle apparatus.

In the refrigeration cycle device according to the present disclosure, refrigerant circulates through the compressor, the first heat exchanger, the decompression device, and the second heat exchanger in this order. A refrigeration cycle device includes a refrigerant container, a first switching section, a second switching section, and a control device. The refrigerant container stores liquid refrigerant. The control device controls the first switching section and the second switching section. When a first condition indicating that the amount of liquid refrigerant stored in the refrigerant container is excessive is satisfied, the control device controls the first switching unit to switch the refrigerant from the compressor through the refrigerant container. The second switching unit is controlled to guide the refrigerant from the second heat exchanger to the compressor without passing through the refrigerant container. When the first condition is not satisfied, the control device controls the first switching unit to guide the refrigerant from the compressor to the first heat exchanger without passing through the refrigerant container, and controls the second switching unit to direct the refrigerant from the compressor to the refrigerant container. to the compressor.

According to the refrigeration cycle device according to the present disclosure, when the first condition indicating that the amount of liquid refrigerant stored in the refrigerant container is excessive is satisfied, the refrigerant from the compressor flows through the refrigerant container to the second condition. 1 heat exchanger, the refrigerant from the second heat exchanger is guided to the compressor without passing through the refrigerant container, and if the first condition is not satisfied, the refrigerant from the compressor flows through the second heat exchanger without passing through the refrigerant container. 1 heat exchanger, and the refrigerant from the refrigerant container is led to the compressor to improve stability.

1 is a functional block diagram showing the configuration of a refrigeration cycle apparatus according to Embodiment 1; FIG. 2 is a functional block diagram showing the configuration of the control device in FIG. 1; FIG. FIG. 2 is a functional block diagram showing the flow of refrigerant when the operation mode of the refrigeration cycle apparatus of FIG. 1 is the refrigerant discharge mode; FIG. 2 is a functional block diagram showing the flow of refrigerant when the operation mode of the refrigeration cycle apparatus of FIG. 1 is the normal mode; 2 is a flow chart showing the flow of processing performed by the control device of FIG. 1; FIG. 4 is a functional block diagram showing the flow of refrigerant when the operation mode of the refrigeration cycle apparatus according to the modified example of Embodiment 1 is the refrigerant discharge mode; FIG. 5 is a functional block diagram showing the flow of refrigerant when the operation mode of the refrigeration cycle device according to the modification of Embodiment 1 is the normal mode; FIG. 6 is a functional block diagram showing the configuration of a refrigeration cycle apparatus according to Embodiment 2; FIG. 9 is a flow chart showing the flow of operation mode switching processing performed by the control device of FIG. 8 ; FIG. FIG. 7 is a functional block diagram showing the configuration of a refrigeration cycle apparatus according to a modification of Embodiment 2; FIG. 11 is a flow chart showing the flow of operation mode switching processing performed by the control device of FIG. 10 ; FIG. FIG. 11 is a functional block diagram showing the configuration of a refrigeration cycle apparatus according to Embodiment 3 together with the flow of refrigerant in an oil recovery mode; FIG. 13 is a flow chart showing the flow of operation mode switching processing performed by the control device of FIG. 12 ; FIG. FIG. 10 is a functional block diagram showing the configuration of a refrigeration cycle device according to Modification 1 of Embodiment 3 together with the flow of refrigerant in an oil recovery mode; FIG. 10 is a functional block diagram showing both the configuration of a refrigeration cycle device according to Modification 2 of Embodiment 3 and the flow of refrigerant in an oil recovery mode; FIG. 10 is a functional block diagram showing the configuration of a refrigeration cycle device according to Modification 3 of Embodiment 3 and the flow of refrigerant in an oil recovery mode together; FIG. 11 is a functional block diagram showing together the configuration of a refrigeration cycle device according to Modification 4 of Embodiment 3 and the flow of refrigerant in an oil recovery mode;

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

Embodiment 1.
FIG. 1 is a functional block diagram showing the configuration of a refrigeration cycle apparatus 100 according to Embodiment 1. As shown in FIG. A refrigerant circulates in the refrigeration cycle device 100 . Examples of the refrigeration cycle device 100 include refrigerators, air conditioners, and showcases.

As shown in FIG. 1, the refrigeration cycle device includes a compressor 1, a condenser 2 (first heat exchanger), an expansion valve 3 (decompression device), and an evaporator 4 (second heat exchanger). , an accumulator 5 (refrigerant container), a switching section 6 (first switching section), a switching section 7 (second switching section), and a control device 10 . In refrigeration cycle device 100, refrigerant circulates through compressor 1, condenser 2, expansion valve 3, and evaporator 4 in this order. The compressor 1 contains refrigerating machine oil (lubricating oil) for lubricating the compression mechanism. The compressor 1 also discharges refrigerating machine oil together with the refrigerant. The accumulator 5 stores liquid refrigerant and refrigerating machine oil. An arrow G1 inside the accumulator 5 indicates the direction of gravity.

The control device 10 controls the driving frequency of the compressor 1 to control the amount of refrigerant discharged by the compressor 1 per unit time. A control device 10 controls the degree of opening of the expansion valve 3 . Control device 10 controls compressor 1 and expansion valve 3 so that the degree of supercooling of the refrigerant flowing out of condenser 2 and the degree of superheating of the refrigerant flowing out of evaporator 4, for example, become target values.

The control device 10 switches the operation mode of the refrigeration cycle device 100 . The operating modes include a refrigerant release mode and a normal mode. The refrigerant release mode is an operation mode for decreasing the amount of liquid refrigerant stored in the accumulator 5 and increasing the amount of refrigerant circulating through the refrigeration cycle device 100 . The normal mode is an operation mode for preventing liquid backflow by storing liquid refrigerant in the accumulator 5 and causing gas refrigerant to flow out from the accumulator 5 to the compressor 1 .

Accumulator 5 includes port Pt1 (first port), port Pt2 (second port), port Pt3 (third port), and port Pt4 (fourth port). A port Pt2 is formed at the bottom of the accumulator 5 . Ports Pt 1 , Pt 3 and Pt 4 are formed above the accumulator 5 . The height of port Pt2 is lower than the height of each of ports Pt1, Pt3, and Pt4. Therefore, the liquid refrigerant can be easily discharged from the port Pt2, and the liquid refrigerant can be suppressed from flowing out from the ports Pt1, Pt3, and Pt4.

The switching unit 6 includes an on-off valve 61 (first valve), an on-off valve 62 (second valve), and an on-off valve 63 (third valve). The on-off valve 61 is connected between the discharge port Ptd of the compressor 1 and the condenser 2 . The on-off valve 62 is connected between the port Pt<b>1 and the flow path FP<b>1 (first flow path) between the discharge port Ptd and the on-off valve 61 . The on-off valve 63 is connected between the port Pt2 and the flow path FP2 (second flow path) between the on-off valve 61 and the condenser 2 .

The switching unit 7 includes an on-off valve 71 (fourth valve), an on-off valve 72 (fifth valve), and an on-off valve 73 (sixth valve). The on-off valve 71 is connected between the evaporator 4 and the intake port Pts of the compressor 1 . The on-off valve 72 is connected between the port Pt3 and the flow path FP3 (third flow path) between the evaporator 4 and the on-off valve 71 . The on-off valve 73 is connected between the port Pt4 and the flow path FP4 (fourth flow path) between the on-off valve 71 and the intake port Pts.

FIG. 2 is a functional block diagram showing the configuration of the control device 10 of FIG. 1. As shown in FIG. As shown in FIG. 2 , control device 10 includes processing circuitry 11 , memory 12 , and input/output section 13 . The processing circuit 11 may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in the memory 12 . When the processing circuit 11 is dedicated hardware, the processing circuit 11 includes, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA ( Field Programmable Gate Array), or a combination of these. When the processing circuit 11 is a CPU, the functions of the control device 10 are implemented by software, firmware, or a combination of software and firmware. Software or firmware is written as a program and stored in memory 12 . The processing circuit 11 reads and executes a program stored in the memory 12 . The memory 12 includes non-volatile or volatile semiconductor memory (for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), or EEPROM (Electrically Erasable Programmable Read Only Memory)). )), and magnetic discs, flexible discs, optical discs, compact discs, mini discs, or DVDs (Digital Versatile Discs). Note that the CPU is also called a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor).

The input/output unit 13 receives an operation from a user and outputs a processing result to the user. The input/output unit 13 includes, for example, a mouse, keyboard, touch panel, display, and speaker.

FIG. 3 is a functional block diagram showing the refrigerant flow when the operation mode of the refrigeration cycle device 100 of FIG. 1 is the refrigerant discharge mode. As shown in FIG. 3 , the control device 10 controls the switching unit 6 to guide the refrigerant from the compressor 1 to the condenser 2 via the accumulator 5 . The control device 10 controls the switching unit 7 to guide the refrigerant from the evaporator 4 to the compressor 1 without passing through the accumulator 5 . The control device 10 closes the on-off valve 61 and opens the on-off valves 62 and 63 . The control device 10 opens the on-off valve 71 and closes the on-off valves 72 and 73 .

FIG. 4 is a functional block diagram showing the flow of refrigerant when the operation mode of the refrigeration cycle device 100 of FIG. 1 is the normal mode. As shown in FIG. 4 , the control device 10 controls the switching unit 6 to guide the refrigerant from the compressor 1 to the condenser 2 without passing through the accumulator 5 . The control device 10 controls the switching unit 7 to guide the refrigerant from the evaporator 4 to the compressor 1 via the accumulator 5 . The control device 10 opens the on-off valve 61 and closes the on-off valves 62 and 63 . The control device 10 closes the on-off valve 71 and opens the on-off valves 72 and 73 .

A relatively large amount of liquid refrigerant may be stored in the accumulator 5 due to the gas refrigerant being cooled and liquefied depending on how long the refrigeration cycle device 100 is stopped. If the normal mode is started in this state, liquid backflow may occur. When liquid backflow occurs, the lubricating performance of the refrigerating machine oil deteriorates, increasing the possibility of the compressor 1 breaking down.

Therefore, in the refrigeration cycle device 100, when the refrigerant release condition (first condition) that the elapsed time from the start of the compressor 1 is shorter than the reference time is satisfied, the refrigerant release mode is performed, and the time from the start of the compressor 1 is The normal mode is performed after the reference time has elapsed. The liquid refrigerant in the accumulator 5 is prevented from being directly sucked into the compressor 1 during the reference time after the compressor 1 is started. Since the amount of liquid refrigerant stored in the accumulator 5 decreases during execution of the refrigerant release mode, the amount of liquid refrigerant stored in the accumulator 5 is released from the accumulator 5 at the start of the normal mode executed after the elapse of the reference time. It can be reduced to the extent that the liquid refrigerant does not flow out. As a result, liquid backflow in the normal mode can be suppressed.

FIG. 5 is a flow chart showing the flow of processing performed by the control device 10 of FIG. The processing shown in FIG. 5 is performed every sampling time by a main routine (not shown) that comprehensively processes the refrigeration cycle apparatus 100 . A step is simply denoted as S below.

As shown in FIG. 5, the controller 10 determines in S101 whether or not the elapsed time since the start of the compressor 1 is shorter than the reference time. If the elapsed time from the startup of compressor 1 is shorter than the reference time (YES in S101), control device 10 sets the operation mode to the refrigerant release mode in S102, and then returns the process to the main routine. If the elapsed time from the startup of the compressor 1 is equal to or longer than the reference time (NO in S101), the controller 10 sets the operation mode to the normal mode in S103 and returns the process to the main routine. Note that the reference time for S101 can be appropriately determined through actual machine experiments or simulations.

In the refrigeration cycle device 100, the case where each of the switching units 6 and 7 includes three on-off valves has been described. The configurations of the first switching section and the second switching section are not limited to the configurations of the switching sections 6 and 7 . Each function of the first switching section and the second switching section can also be realized by a four-way valve.

FIG. 6 is a functional block diagram showing the flow of refrigerant when the operation mode of the refrigeration cycle device 100A according to the modification of Embodiment 1 is the refrigerant release mode. The configuration of the refrigeration cycle device 100A is a configuration in which the switching units 6 and 7 of the refrigeration cycle device 100 of FIG. 1 are replaced with a four-way valve 6A (first four-way valve) and a four-way valve 7A (second four-way valve), respectively. Since they are the same except for these, the description will not be repeated.

As shown in FIG. 6, the four-way valve 6A allows communication between the discharge port Ptd and the port Pt1 and communication between the port Pt2 and the condenser 2. As shown in FIG. The four-way valve 7A communicates between the port Pt3 and the port Pt4 and communicates between the evaporator 4 and the intake port Pts.

FIG. 7 is a functional block diagram showing the flow of refrigerant when the operation mode of refrigeration cycle apparatus 100A according to the modification of Embodiment 1 is the normal mode. As shown in FIG. 7, the four-way valve 6A allows communication between the discharge port Ptd and the condenser 2 and communication between the ports Pt1 and Pt2. The four-way valve 7A communicates between the port Pt3 and the evaporator 4 and between the port Pt4 and the intake port Pts.

As described above, according to the refrigeration cycle apparatus according to the first embodiment and the modification, stability can be improved.

Embodiment 2.
In the first embodiment, the amount of liquid refrigerant stored in the refrigerant container may be excessive when the compressor is started. The configuration in which the refrigerant release mode is executed when the short refrigerant release condition is satisfied has been described. The refrigerant release condition is a condition indicating that liquid backflow is highly likely to occur, and is not limited to the condition that the elapsed time from the startup of the compressor is shorter than the reference time. In the second embodiment, the refrigerant release mode is selected by focusing on the liquid level of the liquid stored in the refrigerant container of the refrigerant container or the concentration of the lubricating oil of the compressor in the liquid stored in the refrigerant container. A configuration for switching between the normal mode will be described.

FIG. 8 is a functional block diagram showing the configuration of a refrigeration cycle apparatus 200 according to Embodiment 2. As shown in FIG. The configuration of the refrigerating cycle device 200 is obtained by adding a liquid level sensor 80 to the configuration of the refrigerating cycle device 100 of FIG. Since they are the same except for these, the description will not be repeated.

As shown in FIG. 8 , the liquid level sensor 80 detects the liquid level height H1 of the liquid stored in the accumulator 5 and outputs it to the control device 20 . The control device 20 switches the operation mode of the refrigeration cycle device 200 according to the height H1. Control device 20 controls compressor 1 and expansion valve 3 in the same manner as control device 10 in FIG. Control device 20 controls switching units 6 and 7 in the same manner as control device 10 in each of the refrigerant release mode and the normal mode.

FIG. 9 is a flowchart showing the flow of operation mode switching processing performed by the control device 20 of FIG. The processing shown in FIG. 9 is performed every sampling time by a main routine (not shown) that comprehensively processes the refrigeration cycle device 200 .

As shown in FIG. 9, the control device 20 determines in S201 whether or not the condition (first condition) that the height H1 is higher than the reference height Hth1 (first reference height) is established. If height H1 is higher than reference height Hth1 (YES in S201), control device 20 sets the operation mode to the refrigerant release mode in S202 and returns the process to the main routine. If height H1 is equal to or less than reference height Hth1 (NO in S201), control device 20 sets the operation mode to the normal mode in S203 and returns the process to the main routine. Note that the reference height Hth1 can be appropriately determined through actual machine experiments or simulations.

FIG. 10 is a functional block diagram showing the configuration of a refrigeration cycle apparatus 200A according to a modification of the second embodiment. The configuration of the refrigeration cycle apparatus 200A is such that the liquid level sensor 80 and the control device 20 of FIG. 8 are replaced with a concentration sensor 81 and a control device 20A, respectively. Since they are the same except for these, the description will not be repeated.

As shown in FIG. 10, the concentration sensor 81 outputs the concentration D1 of refrigerating machine oil in the liquid stored in the accumulator 5 to the control device 20A. 20 A of control apparatuses switch the operation mode of 200 A of refrigerating-cycle apparatuses according to the density|concentration D1.

FIG. 11 is a flow chart showing the flow of operation mode switching processing performed by the control device 20A of FIG. The processing shown in FIG. 11 is performed every sampling time by a main routine (not shown) that comprehensively processes the refrigeration cycle apparatus 200A.

As shown in FIG. 11, the control device 20A determines in S211 whether or not the condition (first condition) that the density D1 is smaller than the reference density Dth1 is established. If concentration D1 is smaller than reference concentration Dth1 (first reference concentration) (YES in S211), control device 20A sets the operation mode to the refrigerant release mode in S212 and returns the process to the main routine. If concentration D1 is greater than or equal to reference concentration Dth1 (NO in S211), control device 20A sets the operation mode to the normal mode in S213 and returns the process to the main routine. Note that the reference density Dth1 can be appropriately determined by actual machine experiments or simulations.

In the refrigerating cycle device 200A, even when the liquid level of the accumulator 5 is relatively high, when the concentration D1 is large, the normal mode is performed assuming that the amount of liquid refrigerant stored in the accumulator 5 is relatively small. will be As a result, liquid backflow can be suppressed and shortage of refrigerating machine oil in the compressor 1 can be suppressed, so the reliability of the compressor 1 can be improved.

In the refrigerating cycle apparatuses 200 and 200A, similarly to the first embodiment, the refrigerant release mode may be performed when the elapsed time from the startup of the compressor 1 is shorter than the reference time. Refrigerant release conditions may include a plurality of conditions among S101 in FIG. 5, S201 in FIG. 9, and S211 in FIG. 11, or may include other conditions.

As described above, according to the refrigeration cycle apparatus according to the second embodiment and the modified example, stability can be improved.

Embodiment 3.
In the third embodiment, in order to appropriately maintain the amount of lubricating oil stored in the compressor when the refrigerant release condition is not satisfied, the normal mode and the compression of the lubricating oil stored in the refrigerant container are performed. A configuration for switching between the oil recovery mode for recovering the oil in the machine will be described.

FIG. 12 is a functional block diagram showing the configuration of the refrigeration cycle device 300 according to Embodiment 3 together with the refrigerant flow in the oil recovery mode. The configuration shown in the refrigeration cycle device 300 is a configuration in which the control device 10 of the refrigeration cycle device 100 of FIG. Since they are the same except for these, the description will not be repeated. The control device 30 executes the refrigerant release mode when the refrigerant release condition is satisfied. When the refrigerant release condition is not satisfied and the oil recovery condition (second condition) indicating that the amount of refrigerating machine oil stored in the compressor 1 is excessive is satisfied, the control device 30 runs the oil recovery mode. When the refrigerant release condition is not satisfied and the oil recovery condition is not satisfied, the control device 30 executes the normal mode. Control device 30 controls switching units 6 and 7 in the same manner as in the first and second embodiments in the oil recovery mode and normal mode.

As shown in FIG. 12 , in the oil recovery mode, control device 30 opens on-off valves 61 and 62 and closes on-off valve 63 . The controller 30 opens the on-off valves 71 and 73 and closes the on-off valve 72 . A part of the refrigerant discharged from the compressor 1 goes to the condenser 2 without passing through the accumulator 5 , and the rest of the refrigerant is sucked into the compressor 1 through the accumulator 5 . Refrigerant oil discharged from the compressor 1 together with the refrigerant is also stored in the accumulator 5 . The amount of refrigerating machine oil circulating in the refrigerating cycle device 300 can be reduced, and the amount of refrigerating machine oil stored in the compressor 1 can be reduced to approach an appropriate amount, so the performance of the refrigerating cycle device 300 can be suppressed.

FIG. 13 is a flowchart showing the flow of operation mode switching processing performed by the control device 30 of FIG. 12 . The processing shown in FIG. 13 is performed every sampling time by a main routine (not shown) that comprehensively processes the refrigeration cycle device 300 .

As shown in FIG. 13, the control device 30 determines whether or not the refrigerant release condition is satisfied in S301. The refrigerant release condition may include a plurality of conditions among S101 in FIG. 5, S201 in FIG. 9, and S211 in FIG. 11, or may include other conditions. If the refrigerant release condition is satisfied (YES in S301), control device 30 sets the operation mode to the refrigerant release mode in S302 and returns the process to the main routine. If the refrigerant release condition is not satisfied (NO in S301), control device 30 determines in S303 whether or not the oil recovery condition is satisfied. As the oil recovery condition, for example, the condition that the amount of change in the driving frequency of the compressor 1 per sampling time (unit time) is smaller than the reference amount can be mentioned. The reference amount can be appropriately determined by actual machine experiments or simulations.

If the oil recovery condition is satisfied (YES in S303), control device 30 sets the operation mode to the oil recovery mode in S304 and returns the process to the main routine. If the oil recovery condition is not satisfied (NO in S303), control device 30 sets the operation mode to the normal mode in S305 and returns the process to the main routine.

The oil recovery condition is not limited to the condition that the amount of change in the driving frequency of the compressor 1 per sampling time is smaller than the reference amount. The oil recovery conditions are, for example, the condition that the temperature of the refrigerant discharged from the compressor 1 (discharge temperature) is higher than the reference temperature, and the height of the liquid level of the liquid stored in the compressor 1 is the reference height ( second reference height), the condition that the concentration of refrigerating machine oil in the liquid stored in the compressor 1 is higher than the reference concentration (second reference concentration), or the liquid stored in the accumulator 5 may include a condition that the liquid level of is lower than a reference height (third reference height). Oil recovery conditions may include a plurality of these conditions, or may include other conditions.

FIG. 14 is a functional block diagram showing together the configuration of a refrigeration cycle device 300A according to Modification 1 of Embodiment 3 and the flow of refrigerant in the oil recovery mode. The configuration of the refrigerating cycle device 300A is obtained by adding a temperature sensor 90 to the configuration of the refrigerating cycle device 300 of FIG. 12 and replacing the control device 30 with 30A. Since they are the same except for these, the description will not be repeated. As shown in FIG. 14, the temperature sensor 90 outputs the discharge temperature Ts to the control device 30A. The oil recovery condition in the refrigeration cycle device 300A includes the condition that the discharge temperature Ts is higher than the reference temperature Tth. Note that the reference temperature Tth can be appropriately determined by actual machine experiments or simulations.

FIG. 15 is a functional block diagram showing both the configuration of a refrigeration cycle device 300B according to Modification 2 of Embodiment 3 and the flow of refrigerant in the oil recovery mode. The configuration of the refrigerating cycle device 300B is obtained by adding a liquid level sensor 91 to the configuration of the refrigerating cycle device 300 of FIG. 12 and replacing the control device 30 with 30B. Since they are the same except for these, the description will not be repeated. As shown in FIG. 15, the liquid level sensor 91 outputs the liquid level height H2 of the liquid stored in the compressor 1 to the control device 30B. In the refrigeration cycle device 300B, the oil recovery condition includes the condition that the height H2 is higher than the reference height Hth2. Note that the reference height Hth2 can be appropriately determined by actual machine experiments or simulations.

FIG. 16 is a functional block diagram showing the configuration of a refrigeration cycle device 300C according to Modification 3 of Embodiment 3 together with the flow of refrigerant in the oil recovery mode. The configuration of the refrigeration cycle device 300C is obtained by adding a concentration sensor 92 to the configuration of the refrigeration cycle device 300 of FIG. 12 and replacing the control device 30 with 30C. Since they are the same except for these, the description will not be repeated. As shown in FIG. 16, the concentration sensor 92 outputs the concentration D2 of refrigerating machine oil in the liquid stored in the compressor 1 to the control device 30C. In the refrigeration cycle device 300C, the oil recovery condition includes the condition that the concentration D2 is greater than the reference concentration Dth2. Note that the reference density Dth2 can be appropriately determined by actual machine experiments or simulations.

FIG. 17 is a functional block diagram showing the configuration of a refrigeration cycle device 300D according to Modification 4 of Embodiment 3 together with the flow of refrigerant in the oil recovery mode. The configuration of the refrigerating cycle device 300D is obtained by adding a liquid level sensor 93 to the configuration of the refrigerating cycle device 300 of FIG. 12 and replacing the control device 30 with 30D. Since they are the same except for these, the description will not be repeated. As shown in FIG. 17, the liquid level sensor 93 outputs the liquid level height H3 of the liquid stored in the accumulator 5 to the controller 30D. In the refrigeration cycle device 300D, the oil recovery condition includes the condition that the height H3 is lower than the reference height Hth3. Note that the reference height Hth3 can be appropriately determined by actual machine experiments or simulations.

As described above, according to the refrigeration cycle apparatuses according to Embodiment 3 and Modifications 1 to 4, stability can be improved.

It is also planned that each embodiment disclosed this time will be appropriately combined and carried out within a non-contradictory range. It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of claims rather than the above description, and is intended to include all changes within the meaning and scope of equivalence to the scope of claims.

1 compressor, 2 condenser, 3 expansion valve, 4 evaporator, 5 accumulator, 6, 7 switching part, 6A, 7A four-way valve, 10, 20, 20A, 30, 30A, 30B, 30C, 30D controller, 11 processing circuit, 12 memory, 13 input/output unit, 61 to 63, 71 to 73 on-off valve, 80, 91, 93 liquid level sensor, 81, 92 concentration sensor, 90 temperature sensor, 100, 100A, 200, 200A, 300, 300A-300D refrigeration cycle device, FP1-FP4 flow paths, Pt1-Pt4 ports, Ptd discharge port, Pts suction port.

Claims (13)

A refrigeration cycle device in which refrigerant circulates in the order of a compressor, a first heat exchanger, a pressure reducing device, and a second heat exchanger,
a refrigerant container that stores the liquid refrigerant;
a first switching unit and a second switching unit;
A control device that controls the first switching unit and the second switching unit,
When a first condition indicating that the amount of the liquid refrigerant stored in the refrigerant container is excessive is satisfied, the control device controls the first switching unit to switch the refrigerant from the compressor to the guide the refrigerant to the first heat exchanger through the refrigerant container, control the second switching unit to guide the refrigerant from the second heat exchanger to the compressor without passing through the refrigerant container;
When the first condition is not satisfied, the control device controls the first switching unit to guide the refrigerant from the compressor to the first heat exchanger without passing through the refrigerant container, and A refrigeration cycle device that controls a switching unit to guide the refrigerant from the second heat exchanger to the compressor through the refrigerant container. 2. The refrigeration cycle apparatus according to claim 1, wherein said first condition includes a condition that an elapsed time from activation of said compressor is shorter than a reference time. 2. The refrigeration cycle apparatus according to claim 1, wherein said first condition includes a condition that the liquid level of the liquid stored in said refrigerant container is higher than a first reference height. 2. The refrigeration cycle apparatus according to claim 1, wherein said first condition includes a condition that a concentration of lubricating oil for said compressor in liquid stored in said refrigerant container is lower than a first reference concentration. A refrigeration cycle device in which refrigerant circulates in the order of a compressor, a first heat exchanger, a pressure reducing device, and a second heat exchanger,
a refrigerant container that stores the liquid refrigerant;
a first switching unit and a second switching unit;
A control device that controls the first switching unit and the second switching unit,
When a first condition indicating that the amount of the liquid refrigerant stored in the refrigerant container is excessive is satisfied, the control device controls the first switching unit to switch the refrigerant from the compressor to the guide the refrigerant to the first heat exchanger through the refrigerant container, control the second switching unit to guide the refrigerant from the second heat exchanger to the compressor without passing through the refrigerant container;
When the first condition is not satisfied, the control device controls the first switching unit to guide the refrigerant from the compressor to the first heat exchanger without passing through the refrigerant container, and controlling a switching unit to guide the refrigerant from the refrigerant container to the compressor;
the refrigerant container includes a first port, a second port, a third port, and a fourth port;
The first switching unit includes a first four-way valve,
The second switching unit includes a second four-way valve,
When the first condition is satisfied, the control device controls the first four-way valve to communicate the discharge port of the compressor and the first port, and the second port and the first heat exchanger. and communicate with, control the second four-way valve to communicate the third port and the fourth port, and communicate the second heat exchanger and the suction port of the compressor,
When the first condition is not satisfied, the control device controls the first four-way valve to allow communication between the discharge port and the first heat exchanger and communication between the first port and the second port. and controlling the second four-way valve to allow communication between the third port and the second heat exchanger and communication between the fourth port and the suction port. A refrigeration cycle device in which refrigerant circulates in the order of a compressor, a first heat exchanger, a pressure reducing device, and a second heat exchanger,
a refrigerant container that stores the liquid refrigerant;
a first switching unit and a second switching unit;
A control device that controls the first switching unit and the second switching unit,
When a first condition indicating that the amount of the liquid refrigerant stored in the refrigerant container is excessive is satisfied, the control device controls the first switching unit to switch the refrigerant from the compressor to the guide the refrigerant to the first heat exchanger through the refrigerant container, control the second switching unit to guide the refrigerant from the second heat exchanger to the compressor without passing through the refrigerant container;
When the first condition is not satisfied, the control device controls the first switching unit to guide the refrigerant from the compressor to the first heat exchanger without passing through the refrigerant container, and controlling a switching unit to guide the refrigerant from the refrigerant container to the compressor;
the refrigerant container includes a first port, a second port, a third port, and a fourth port;
The first switching unit includes a first valve, a second valve, and a third valve,
the first valve is connected between a discharge port of the compressor and the first heat exchanger;
the second valve is connected between the first port and a first flow path between the discharge port and the first valve;
The second switching unit includes a fourth valve, a fifth valve, and a sixth valve,
the third valve is connected between the second port and a second flow path between the first valve and the first heat exchanger;
the fourth valve is connected between the second heat exchanger and an intake port of the compressor;
the fifth valve is connected between the third port and a third flow path between the second heat exchanger and the fourth valve;
the sixth valve is connected between the fourth port and a fourth flow path between the fourth valve and the intake port;
When the first condition is satisfied, the control device closes the first valve, opens the second valve and the third valve, opens the fourth valve, opens the fifth valve and the third valve. Close valve 6,
When the first condition is not satisfied, the control device opens the first valve , closes the second and third valves, closes the fourth valve, and closes the fifth and third valves. A refrigeration cycle device that opens 6 valves. When the first condition is not satisfied and the second condition indicating that the amount of lubricating oil stored in the compressor is excessive is satisfied, the control device controls the first valve and the second valve. opening a valve, closing the third valve, opening the fourth valve, closing the fifth valve, opening the sixth valve,
When the first condition is not satisfied and the second condition is not satisfied, the control device opens the first valve, closes the second valve and the third valve, and closes the fourth valve. 7. The refrigeration cycle apparatus according to claim 6, wherein said fifth valve and said sixth valve are closed and opened. 8. The refrigeration cycle apparatus according to claim 7, wherein said second condition includes a condition that an amount of change per unit time of the driving frequency of said compressor is smaller than a reference amount. 8. The refrigeration cycle apparatus according to claim 7, wherein said second condition includes a condition that the temperature of said refrigerant discharged from said compressor is higher than a reference temperature. 8. The refrigeration cycle apparatus according to claim 7, wherein said second condition includes a condition that the liquid level of the liquid stored in said compressor is higher than a second reference height. 8. The refrigeration cycle apparatus according to claim 7, wherein said second condition includes a condition that a concentration of lubricating oil of said compressor in liquid stored in said compressor is higher than a second reference concentration. 8. The refrigeration cycle apparatus according to claim 7, wherein said second condition includes a condition that the liquid level of the liquid stored in said refrigerant container is lower than a third reference height. The refrigeration cycle apparatus according to any one of claims 5 to 12, wherein the height of said second port is lower than the height of each of said first port, said third port and said fourth port.

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