Air conditioner

Abstract

This air conditioner (10) comprises an indoor unit (11), an outdoor unit (12), a first shutoff valve (8), a second shutoff valve (9), and a control device (200). The indoor unit (11) is provided with a first heat exchanger (2). The outdoor unit (12) is provided with a compressor (1), a second heat exchanger (4), and an expansion valve (3) for expanding a refrigerant in a first refrigerant path (101). The first shutoff valve (8) shuts off the first refrigerant path (101). The second shutoff valve (9, 9c, 9d) shuts off a second refrigerant path (102) between the compressor (1) and the first heat exchanger (2). In response to a stop of the compressor (1), the control device (200) shuts off the first refrigerant path (101) by means of the first shutoff valve (8) and shuts off the second refrigerant path (102) by means of the second shutoff valve (9).

Description

air conditioning equipment

[0001] The present disclosure relates to an air conditioning apparatus.

[0002] The air conditioning apparatus includes an indoor unit and an outdoor unit. The indoor unit is provided with a first heat exchanger. The outdoor unit is provided with a compressor, an expansion valve, and a second heat exchanger. These devices provided in the indoor unit and the outdoor unit are connected by piping. The devices and piping provided in the indoor unit and the outdoor unit form a refrigerant circuit in which a refrigerant circulates.

[0003] When the air conditioner is operating, the refrigerant passes through these devices and circulates through the refrigerant circuit. When the air conditioner is not operating, the refrigerant generally moves from high-temperature parts to low-temperature parts in the refrigerant circuit.

[0004] For example, when the temperature of the outdoor unit is lower than that of the indoor unit while the air conditioner is not operating, the refrigerant moves from the indoor unit to the outdoor unit, and a large amount of liquid refrigerant accumulates in the second heat exchanger of the outdoor unit.

[0005] Patent Document 1 discloses that when the operation of the air conditioner is terminated, a refrigerant recovery operation is performed in which refrigerant is recovered from the refrigerant circuit on the indoor unit side and stored in the refrigerant circuit on the outdoor unit side.

[0006] JP 2022-24289 A

[0007] However, in the conventional air conditioning system described above, when the air conditioning system is stopped, the refrigerant moves from the indoor unit to the outdoor unit, and a large amount of liquid refrigerant accumulates in the outdoor unit. Therefore, when the air conditioning system starts operating, a liquid backflow occurs in which a large amount of liquid refrigerant is supplied to the compressor in the outdoor unit, which could cause problems such as compressor failure.

[0008] The present disclosure is intended to solve the above-mentioned problems, and has as its object to provide an air conditioner that can suppress the occurrence of liquid backflow when starting operation.

[0009] The present disclosure relates to an air conditioner. The air conditioner includes an outdoor unit, an indoor unit, a compressor provided in the outdoor unit for compressing a refrigerant, a first heat exchanger provided in the indoor unit for exchanging heat between the refrigerant and indoor air, a second heat exchanger provided in the outdoor unit for exchanging heat between the refrigerant and outdoor air, an expansion valve provided in the outdoor unit for expanding the refrigerant in a first refrigerant path between the first and second heat exchangers, a first shutoff valve capable of shutting off the first refrigerant path, a second shutoff valve capable of shutting off a second refrigerant path between the compressor and the first heat exchanger, and a control device for controlling air conditioning. The control device controls the first shutoff valve to shut off the first refrigerant path and the second shutoff valve to shut off the second refrigerant path in response to a stop of the compressor.

[0010] According to the air conditioning apparatus of the present disclosure, when the compressor stops, the first refrigerant path is blocked by the first shut-off valve, and the second refrigerant path is blocked by the second shut-off valve, thereby suppressing the flow of refrigerant into the outdoor unit when the operation is stopped, and thereby suppressing the occurrence of liquid backflow when the operation is started.

[0011] FIG. 1 is a diagram showing the configuration of an air conditioning apparatus according to embodiment 1. FIG. 2 is a flowchart of an example of control of the first shut-off valve and the second shut-off valve according to embodiment 1. FIG. 3 is a diagram showing the configuration of an air conditioning apparatus according to embodiment 2. FIG. 4 is a diagram showing the flow of refrigerant in a time-staggered shut-off mode in the air conditioning apparatus according to embodiment 2. FIG. 5 is a flowchart of an example of control of the first shut-off valve and the second shut-off valve according to embodiment 2. FIG. 6 is a diagram showing the configuration of an air conditioning apparatus according to embodiment 3. FIG. 7 is a diagram showing the configuration of an air conditioning apparatus according to embodiment 4. FIG. 8 is a diagram showing the configuration of an air conditioning apparatus according to embodiment 5. FIG. 9 is a diagram showing the configuration of an air conditioning apparatus according to embodiment 6. FIG. 10 is a diagram showing the schematic configuration of a second heat exchanger according to embodiment 7. FIG. 11 is a side view of the second heat exchanger in the case where two rows of heat transfer tubes are provided in embodiment 7.

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. While several embodiments will be described below, it was originally intended that the configurations described in each embodiment be combined as appropriate. Note that identical or corresponding parts in the drawings will be designated by the same reference numerals, and their description will not be repeated.

[0013] Embodiment 1 (Overall configuration of air conditioning apparatus 10) Fig. 1 is a diagram showing the configuration of an air conditioning apparatus 10 according to embodiment 1. The air conditioning apparatus 10 includes an indoor unit 11 and an outdoor unit 12. The indoor unit 11 and the outdoor unit 12 are connected by a first extension pipe 6 and a second extension pipe 7.

[0014] The indoor unit 11 includes a first heat exchanger 2. In the indoor unit 11, a blower fan 20 is provided corresponding to the first heat exchanger 2.

[0015] The outdoor unit 12 includes a compressor 1, a second heat exchanger 4, an expansion valve 3, a flow path switching device 52, an accumulator 51, a first shutoff valve 8, a second shutoff valve 9, and a control device 200. In the outdoor unit 12, a blower fan 40 is provided corresponding to the second heat exchanger 4.

[0016] In the air conditioning apparatus 10, a basic refrigeration cycle is formed by a compressor 1, a first heat exchanger 2, an expansion valve 3, and a second heat exchanger 4. In the air conditioning apparatus 10, a refrigerant is circulated in a refrigerant circuit 100 that is provided with a flow switching device 52, an accumulator 51, a first shut-off valve 8, and a second shut-off valve 9 in addition to the compressor 1, the first heat exchanger 2, the expansion valve 3, and the second heat exchanger 4.

[0017] The first heat exchanger 2 exchanges heat between the refrigerant and the indoor air. The first heat exchanger 2 functions as a refrigerant condenser during heating operation and as a refrigerant evaporator during cooling operation. The fan 20 draws in indoor air and expels the air that has exchanged heat with the refrigerant through the first heat exchanger 2 into the room.

[0018] The second heat exchanger 4 exchanges heat between the refrigerant and the outdoor air. The second heat exchanger 4 functions as a refrigerant evaporator during heating operation and as a refrigerant condenser during cooling operation. The fan 40 draws in outdoor air and expels the air that has exchanged heat with the refrigerant in the first heat exchanger 2 to the outside.

[0019] A compressor 1 for compressing the refrigerant is provided in the refrigerant path between the first heat exchanger 2 and the second heat exchanger 4. The compressor 1 is driven by, for example, an inverter-controlled motor.

[0020] An expansion valve 3 is provided in the refrigerant path between the first heat exchanger 2 and the second heat exchanger 4. The second heat exchanger 4, the compressor 1, the first heat exchanger 2, and the expansion valve 3 are connected in series in the refrigerant circuit 100.

[0021] The expansion valve 3 has a function of decompressing and expanding the refrigerant, and is configured, for example, as an electronic expansion valve capable of adjusting the flow rate. The expansion valve 3 decompresses and expands the refrigerant, and can adjust the flow rate of the refrigerant in the refrigerant path both during cooling operation and heating operation.

[0022] The flow path switching device 52 is provided between the discharge side of the compressor 1 and each of the first heat exchanger 2 and the second heat exchanger 4. The refrigerant path on the discharge side of the compressor 1 is connected to either the first heat exchanger 2 or the second heat exchanger 4 via the flow path switching device 52. The flow path switching device 52 switches the flow path through which the refrigerant discharged from the compressor 1 flows between a flow path leading to the first heat exchanger 2 and a flow path leading to the second heat exchanger 4. The flow path switching device 52 is configured, for example, by a four-way valve.

[0023] The accumulator 51 is provided between the suction port of the compressor 1 and the flow path switching device 52. The accumulator 51 is a gas-liquid separation device that is capable of separating a refrigerant into a gas refrigerant and a liquid refrigerant, sending the gas refrigerant to the suction side of the compressor 1, and storing the liquid refrigerant. The accumulator 51 separates the refrigerant supplied from the first heat exchanger 2 or the second heat exchanger 4 via the flow path switching device 52 into a gas refrigerant and a liquid refrigerant.

[0024] A first extension pipe 6 is provided in the refrigerant path between the first heat exchanger 2 of the indoor unit 11 and the expansion valve 3 of the outdoor unit 12. A second extension pipe 7 is provided in the refrigerant path between the first heat exchanger 2 of the indoor unit 11 and the flow path switching device 52 of the outdoor unit 12.

[0025] In the outdoor unit 12, a first shutoff valve 8 is provided between the expansion valve 3 and the first extension pipe 6. When the first shutoff valve 8 is in a closed state, it is possible to shut off the first refrigerant path 101 between the first heat exchanger 2 and the second heat exchanger 4.

[0026] In the outdoor unit 12, a second shutoff valve 9 is provided between the flow path switching device 52 and the second extension pipe 7. When the second shutoff valve 9 is in a closed state, it is possible to shut off the second refrigerant path 102 between the compressor 1 and the first heat exchanger 2.

[0027] The control device 200 is composed of a CPU (Central Processing Unit) 201, memory 202 (ROM (Read Only Memory) and RAM (Random Access Memory)), an input / output buffer (not shown), etc. The CPU 201 deploys programs stored in the ROM into the RAM etc. and executes them. The programs stored in the ROM are programs in which the processing procedures of the control device 200 are written. The control device 200 controls various devices in the air conditioning device 10 in accordance with these programs. Control of such devices is not limited to processing by software, but can also be processed by dedicated hardware (electronic circuits).

[0028] The air conditioning apparatus 10 is provided with various sensors capable of detecting conditions such as temperature, pressure, and rotation speed at predetermined locations. Detection signals from these various sensors are input to the control device 200. The control device 200 confirms the state of the air conditioning apparatus 10 based on the detection signals from the various sensors, and issues control signals to the compressor 1, expansion valve 3, flow path switching device 52, first shut-off valve 8, second shut-off valve 9, etc.

[0029] The control device 200 controls the operating frequency of the compressor 1 using the control signal described above. The control device 200 controls the opening degree of the expansion valve 3 using the control signal described above. The control device 200 controls the switching of the flow path of the flow path switching device 52 using the control signal described above. The control device 200 controls the open / close state of the first shutoff valve 8 using the control signal described above. The control device 200 controls the open / close state of the second shutoff valve 9 using the control signal described above.

[0030] 1, as an example of a detection signal, a detection signal of a sensor (not shown) that detects the rotation speed of the compressor 1 is indicated by a dashed arrow. In Fig. 1, as an example of a control signal, a control signal of the first shutoff valve 8 is indicated by a dashed arrow, and a control signal of the second shutoff valve 9 is also indicated by a dashed arrow.

[0031] (Example of Basic Operation of Air Conditioning Apparatus 10) Next, the operation of the air conditioning apparatus 10 will be described using FIG.

[0032] First, a description will be given of the operation during heating operation of the air conditioning apparatus 10. During heating operation, the control device 200 controls the flow path in the flow path switching device 52 to become the flow path shown by the solid line in FIG.

[0033] During heating operation, high-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 1 flows out of the outdoor unit 12 through the flow switching device 52 and the second shutoff valve 9, which is in an open state. The gas refrigerant that flows out of the outdoor unit 12 flows into the indoor unit 11 through the second extension pipe 7. The gas refrigerant that flows into the indoor unit 11 flows into the first heat exchanger 2.

[0034] In the first heat exchanger 2, heat is exchanged between the high-temperature, high-pressure gas refrigerant that has flowed in and the indoor air. As a result, the gas refrigerant releases heat through heat exchange with the indoor air and is condensed to become a high-pressure liquid refrigerant. The refrigerant that has changed from gas refrigerant to liquid refrigerant in the first heat exchanger 2 flows out of the indoor unit 11 in the direction of the first extension pipe 6 from the first heat exchanger 2. The liquid refrigerant that has flowed out of the indoor unit 11 passes through the first extension pipe 6 and flows into the outdoor unit 12. The gas refrigerant that has flowed into the outdoor unit 12 flows into the expansion valve 3 via the first shutoff valve 8, which is in an open state.

[0035] In the expansion valve 3, the inflowing high-pressure liquid refrigerant expands and is decompressed to become a low-temperature, low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant after being expanded and decompressed in the expansion valve 3 flows into the second heat exchanger 4. In the second heat exchanger 4, heat is exchanged between the inflowing two-phase gas-liquid refrigerant and the outdoor air. The two-phase gas-liquid refrigerant evaporates through heat exchange with the outdoor air and becomes a low-temperature, low-pressure gas refrigerant. The refrigerant that has changed from the two-phase gas-liquid refrigerant to the gas refrigerant in the second heat exchanger 4 flows out from the second heat exchanger 4 toward the flow path switching device 52.

[0036] The refrigerant flowing out of the second heat exchanger 4 flows into the accumulator 51 via the flow switching device 52. The refrigerant flowing into the accumulator 51 is separated into gas refrigerant and liquid refrigerant. The accumulator 51 stores the liquid refrigerant in the refrigerant path on the suction port side of the compressor 1 and supplies the gas refrigerant to the suction port of the compressor 1. This allows the accumulator 51 to suppress the occurrence of liquid backflow. The compressor 1 draws the gas refrigerant supplied from the accumulator 51 through the suction port, compresses the gas refrigerant, and discharges the high-temperature, high-pressure gas refrigerant as described above through the discharge port.

[0037] Next, a description will be given of the operation during cooling operation of the air conditioner 10. During cooling operation, the control device 200 controls the flow path in the flow path switching device 52 to become the flow path shown by the dashed line in FIG.

[0038] In the outdoor unit 12, the high-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 1 flows into the second heat exchanger 4 via the flow switching device 52. In the second heat exchanger 4, heat is exchanged between the inflowing high-temperature, high-pressure gas refrigerant and the outdoor air. As a result, the gas refrigerant releases heat through heat exchange with the outdoor air and is condensed into a high-pressure liquid refrigerant. The refrigerant that has changed from gas refrigerant to liquid refrigerant in the second heat exchanger 4 flows from the second heat exchanger 4 into the expansion valve 3.

[0039] In the expansion valve 3, the inflowing high-pressure liquid refrigerant flows into the expansion valve 3, where it is expanded and decompressed to become a low-temperature, low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant after being expanded and decompressed in the expansion valve 3 flows out of the outdoor unit 12 through the first shutoff valve 8, which is in an open state. The gas-liquid two-phase refrigerant that flows out of the outdoor unit 12 flows into the indoor unit 11 through the first extension pipe 6. The gas-liquid two-phase refrigerant that flows into the indoor unit 11 flows into the first heat exchanger 2.

[0040] In the first heat exchanger 2, heat is exchanged between the inflowing gas-liquid two-phase refrigerant and the indoor air. The gas-liquid two-phase refrigerant evaporates through heat exchange with the outdoor air and becomes a low-temperature, low-pressure gas refrigerant. The refrigerant that has changed from the gas-liquid two-phase refrigerant to gas refrigerant in the first heat exchanger 2 flows out of the indoor unit 11 from the first heat exchanger 2 toward the second extension pipe 7. The liquid refrigerant that has flowed out of the indoor unit 11 flows into the accumulator 51 via the second shutoff valve 9 and the flow switching device 52.

[0041] The refrigerant that flows into the accumulator 51 is separated into gas refrigerant and liquid refrigerant. The accumulator 51 stores the liquid refrigerant in the refrigerant path on the suction port side of the compressor 1, and supplies the gas refrigerant to the suction port of the compressor 1. This allows the accumulator 51 to suppress the occurrence of liquid backflow. The compressor 1 draws the gas refrigerant supplied from the accumulator 51 from the suction port, compresses the gas refrigerant, and discharges the high-temperature, high-pressure gas refrigerant as described above from the discharge port.

[0042] (Control Example of First Shutoff Valve 8 and Second Shutoff Valve 9) Fig. 2 is a flowchart of a control example of the first shutoff valve 8 and the second shutoff valve 9 according to embodiment 1. The control shown in Fig. 2 is executed by the control device 200 shown in Fig. 1 .

[0043] In step S1, the control device 200 determines whether the compressor 1 is currently operating. In step S1, for example, the control device 200 determines whether the compressor 1 is operating based on a detection signal input from a sensor that detects the rotation speed of the compressor 1. For example, the control device 200 determines that the compressor 1 is not operating when the rotation speed detected by the sensor is less than the lower limit of the rotation speed used in the normal operation mode. The control device 200 determines that the compressor 1 is operating when the rotation speed detected by the sensor is equal to or greater than the lower limit of the rotation speed used in the normal operation mode. Note that the determination of whether the compressor 1 is operating may also be made based on whether a stop signal for stopping the operation of the compressor 1 has been transmitted.

[0044] If the compressor 1 is currently operating in step S1, the control device 200 performs control in step S2 to open both the first shutoff valve 8 and the second shutoff valve 9. When both the first shutoff valve 8 and the second shutoff valve 9 are open in this way, both the first refrigerant path 101 and the second refrigerant path 102 are not shut off, and therefore it is possible to circulate refrigerant in the refrigerant circuit 100. The mode in which both the first shutoff valve 8 and the second shutoff valve 9 are open in this way is called the normal operation mode.

[0045] On the other hand, if it is determined in step S1 that the compressor 1 is not currently operating, the control device 200 performs control in step S3 to simultaneously close both the first shutoff valve 8 and the second shutoff valve 9. This mode in which both the first shutoff valve 8 and the second shutoff valve 9 are simultaneously closed is called a simultaneous shutoff mode.

[0046] In this way, when both the first shut-off valve 8 and the second shut-off valve 9 are closed, the first refrigerant path 101 and the second refrigerant path 102 are blocked, thereby suppressing the flow of refrigerant from outside the outdoor unit 12 to inside the outdoor unit 12.

[0047] For example, when the temperature of the outdoor unit 12 is lower than the temperature of the indoor unit 11, such as when the heating operation is stopped after the heating operation has been performed, the refrigerant may flow from the indoor unit 11, which has a higher temperature, to the outdoor unit 12, which has a lower temperature, and the refrigerant may try to flow into the outdoor unit 12.

[0048] However, in the first embodiment, when the operation of the compressor 1 is stopped, both the first shutoff valve 8 and the second shutoff valve 9 are controlled to a closed state, thereby suppressing the inflow of refrigerant from the indoor unit 11 to the outdoor unit 12. Therefore, when the operation of the compressor 1 is stopped, a large amount of liquid refrigerant is suppressed from accumulating in various locations in the outdoor unit 12. This makes it possible to suppress the occurrence of liquid backflow, in which liquid refrigerant is sucked into the compressor 1, when the operation of the compressor 1 is started.

[0049] In the first embodiment, in response to the stop of operation of the compressor 1, the control device 200 controls the first shutoff valve 8 and the second shutoff valve 9 to enter a simultaneous shutoff mode in which both the first shutoff valve 8 and the second shutoff valve 9 are closed simultaneously. In other words, in response to the stop of operation of the compressor 1, the control device 200 performs control to simultaneously shut off the first refrigerant path 101 and the second refrigerant path 102. As a result, in the first embodiment, it is possible to quickly suppress the inflow of refrigerant from the indoor unit 11 side to the outdoor unit 12 side after the stop of operation of the compressor 1.

[0050] As in conventional general air conditioners, after the compressor stops operating, if the temperature of the outdoor unit is lower than that of the indoor unit, refrigerant flows from the indoor unit to the outdoor unit. If a large amount of liquid refrigerant is present in the outdoor unit, a large amount of liquid refrigerant flows into the accumulator. Therefore, in conventional general air conditioners, as the amount of refrigerant circulating in the air conditioner increases by lengthening the extension piping, the accumulator needs to be made larger. Furthermore, even if an air conditioner is provided with a suction muffler that separates gas and liquid refrigerants instead of an accumulator, the suction muffler also needs to be made larger for the same reason as the amount of refrigerant circulating in the air conditioner increases.

[0051] However, in the air conditioning apparatus 10 of embodiment 1, both the first shutoff valve 8 and the second shutoff valve 9 are controlled to a closed state in response to the operation of the compressor 1 being stopped, thereby suppressing the inflow of refrigerant from the indoor unit 11 to the outdoor unit 12, and therefore suppressing the amount of liquid refrigerant flowing into the accumulator 51 after the operation of the compressor 1 is stopped. As a result, in the air conditioning apparatus 10 of embodiment 1, it is possible to suppress an increase in the size of the accumulator 51. Furthermore, for the same reason, even in an air conditioning apparatus provided with a suction muffler that separates gas and liquid refrigerant instead of the accumulator 51, it is possible to suppress an increase in the size of the suction muffler.

[0052] Embodiment 2 In Embodiment 2, an example will be described in which the time-staggered shutoff mode is executed. In the time-staggered shutoff mode, when the operation of the compressor 1 is stopped, the control device 200 closes the first shutoff valve 8 at a first timing and then closes the second shutoff valve 9 at a second timing, thereby moving the refrigerant present on the outdoor unit 12 side to the indoor unit 11 side and recovering it for a predetermined period after the operation of the compressor 1 is stopped.

[0053] (Overall configuration of air conditioning apparatus 10A) Figure 3 is a diagram showing the configuration of air conditioning apparatus 10A of embodiment 2. Referring to Figure 3, the configuration of air conditioning apparatus 10A differs from the configuration of air conditioning apparatus 10 in Figure 1 in that a second shut-off valve 9 is provided in the indoor unit 11 between the first heat exchanger 2 and the second extension pipe 7.

[0054] Figure 4 is a diagram showing the flow of refrigerant in the time-lag shutdown mode in the air conditioning apparatus 10A of embodiment 2. In Figure 4, in order to clearly show the flow of refrigerant, the frame lines indicating the range of the indoor unit 11 and the frame lines indicating the range of the outdoor unit 12 shown in Figure 3 have been omitted. In the time-lag shutdown mode, when operation of the compressor 1 is stopped, the first shut-off valve 8 is closed, and then the second shut-off valve 9 remains open for a predetermined period of time.

[0055] After the compressor 1 is stopped while the heating operation is being performed, a phenomenon occurs in which the refrigerant flows through the refrigerant circuit 100 for a certain period of time, as shown by the two-dot chain arrow in the figure. In this state in which the refrigerant flows through the refrigerant circuit 100 after the compressor 1 is stopped, if the first shutoff valve 8 is closed and the second shutoff valve 9 remains open, the refrigerant present inside the outdoor unit 12 flows out of the outdoor unit 12 and moves toward the indoor unit 11. The refrigerant that flows out of the outdoor unit 12 flows into the indoor unit 11 via the second extension pipe 7 and the second shutoff valve 9. The refrigerant present in the indoor unit 11 and the first extension pipe 6 is blocked from flowing into the outdoor unit 12 because the first shutoff valve 8 is closed.

[0056] When the operation of the compressor 1 is stopped while the heating operation is being performed, the first shutoff valve 8 is controlled to the closed state, and after a predetermined period of time has elapsed, the second shutoff valve 9 is controlled to the closed state, thereby closing both the first shutoff valve 8 and the second shutoff valve 9. This ends the time-staggered shutoff mode. In this way, in the time-staggered shutoff mode, when the operation of the compressor 1 is stopped, the refrigerant present on the outdoor unit 12 side is recovered to the indoor unit 11 side for a predetermined period of time.

[0057] After the time-delay shut-off mode ends, the first shut-off valve 8 and the second shut-off valve 9 are maintained in a closed state until the next operation of the compressor 1 is started, so that the refrigerant present in the indoor unit 11 and the first extension pipe 6 is prevented from flowing into the outdoor unit 12.

[0058] (Example of Control of First Shutoff Valve 8 and Second Shutoff Valve 9) Next, an example of control of the first shutoff valve 8 and the second shutoff valve 9 by the control device 200 in the second embodiment will be described with reference to FIG.

[0059] 5 is a flowchart of an example of control of the first shutoff valve 8 and the second shutoff valve 9 according to the second embodiment. The control shown in FIG. 5 is executed by the control device 200 shown in FIGS.

[0060] In steps S11 and S12, the control device 200 executes the same processes as in steps S1 and S2 shown in FIG.

[0061] If it is determined in step S11 that the compressor 1 is not currently operating, the control device 200 resets the value of the timer T in step S13. The timer T in step S13 is used to count the period during which the second shutoff valve 9 is maintained in the open state in the time-differential shutoff mode.

[0062] In step S14, the control device 200 performs control to close the first shutoff valve 8 and open the second shutoff valve 9. Since both the first shutoff valve 8 and the second shutoff valve 9 are open while the compressor 1 is operating, in step S14 the control device 200 performs control to close the first shutoff valve 8 when the operation of the compressor 1 is stopped. The first timing at which the first shutoff valve 8 is closed and the second shutoff valve 9 is open is the start timing of the time-staggered shutoff mode described above.

[0063] In this time-delay shutoff mode in which the first shutoff valve 8 is closed and the second shutoff valve 9 is open, as described above, the refrigerant present on the outdoor unit 12 side flows toward the indoor unit 11 side.

[0064] In step S15, the control device 200 counts up the value of the timer T. In step S15, the value of the timer T is counted up as time passes. In step S16, the control device 200 determines whether the value of the timer T has reached a specified value. The specified value in step S16 is a timer value set to a value corresponding to the duration of the time-staggered shut-off mode.

[0065] If the value of timer T has not reached the specified value in step S16, the control device 200 returns to step S15 and counts up the value of timer T. As a result, in step S15, the value of timer T is updated as time passes. Note that the updating of timer T in step S15 may be performed as time passes by a subroutine program separate from the processing shown in FIG.

[0066] If the value of timer T reaches the specified value in step S16, this means that the duration of the time-staggered shutoff mode has elapsed. If the value of timer T reaches the specified value in step S16, the control device 200 controls the second shutoff valve 9 to a closed state in step S17, thereby controlling both the first shutoff valve 8 and the second shutoff valve 9 to a closed state. The second timing at which the second shutoff valve 9 is closed in this way, thereby closing both the first shutoff valve 8 and the second shutoff valve 9, is the timing at which the time-staggered shutoff mode ends.

[0067] When the time-delayed shutoff mode ends in this way, the first shutoff valve 8 and the second shutoff valve 9 are maintained in a closed state until the next operation of the compressor 1 is started, so that the refrigerant present in the indoor unit 11 and the first extension pipe 6 is blocked from flowing into the outdoor unit 12. This prevents refrigerant from flowing from outside the outdoor unit 12 into the outdoor unit 12. Therefore, when the compressor 1 is stopped, a large amount of liquid refrigerant is prevented from accumulating in various locations in the outdoor unit 12. This makes it possible to prevent the occurrence of liquid backflow, in which liquid refrigerant is sucked into the compressor 1, when the compressor 1 starts operating.

[0068] In the second embodiment, in response to the stop of operation of compressor 1, control device 200 controls first shutoff valve 8 and second shutoff valve 9 to enter a time-staggered shutoff mode in which first shutoff valve 8 is closed at a first timing and then second shutoff valve 9 is closed at a second timing. In other words, in response to the stop of operation of compressor 1, control device 200 performs control to shut off first refrigerant path 101 at a first timing and then shut off second refrigerant path 102 at a second timing. Therefore, in the second embodiment, after the stop of operation of compressor 1, refrigerant can be recovered from outdoor unit 12 to indoor unit 11, thereby reducing the amount of refrigerant held in outdoor unit 12. As a result, in the second embodiment, the occurrence of liquid backflow, in which liquid refrigerant is drawn into compressor 1 when compressor 1 starts operating, can be further suppressed.

[0069] In the second embodiment, the following effects can also be obtained. Generally, extension pipes such as the first extension pipe 6 and the second extension pipe 7 are installed outdoors, similar to the outdoor unit 12. Therefore, the first extension pipe 6 and the second extension pipe 7 have a lower temperature than the indoor unit 11, and when the operation of the compressor 1 is stopped, the refrigerant moves from the indoor unit 11, making it easier for liquid refrigerant to accumulate.

[0070] When the compressor 1 is started for heating operation after being stopped, if a large amount of liquid refrigerant is stored in the second extension pipe 7, it may take a long time for the liquid refrigerant to reach the compressor 1 from the second extension pipe 7, through the first heat exchanger 2, the first extension pipe 6, the expansion valve 3, the second heat exchanger 4, and the accumulator 51, etc., as the refrigerant to be supplied to the compressor 1. In such a case, the amount of refrigerant drawn into the compressor 1 may be insufficient when the compressor 1 starts operating.

[0071] However, in the second embodiment, the second shutoff valve 9 is provided in the indoor unit 11, so in the time-delayed shutoff mode, the recovered refrigerant is stored in the indoor unit 11 and the first extension pipe 6. Therefore, when the compressor 1 is in the operation start state for heating operation, the refrigerant recovered in the time-delayed shutoff mode can be supplied to the compressor 1 as soon as possible, so that a shortage of the amount of refrigerant drawn into the compressor 1 can be prevented when the compressor 1 is in the operation start state.

[0072] The time-staggered shutdown mode may be implemented in the air conditioning apparatus 10 configured as shown in Fig. 1. The simultaneous shutdown mode as described in the first embodiment may be implemented in the air conditioning apparatus 10A configured as shown in Fig. 2.

[0073] Third Embodiment In a third embodiment, another example of the arrangement of the first shutoff valve 8 and the second shutoff valve 9 will be described. Fig. 6 is a diagram showing the configuration of an air conditioning apparatus 10B according to the third embodiment.

[0074] Referring to Figure 6, the configuration of the air conditioning apparatus 10B differs from the above-mentioned embodiments 1 and 2 in that a first shut-off valve 8 is provided in the indoor unit 11 between the first heat exchanger 2 and the first extension pipe 6, and a second shut-off valve 9 is provided in the outdoor unit 12 between the flow path switching device 52 and the second extension pipe 7.

[0075] In the configuration of air conditioning apparatus 10B in Embodiment 3, first shutoff valve 8 and second shutoff valve 9 are controlled by control device 200 in the simultaneous shutoff mode shown in Embodiment 1 or the time-staggered shutoff mode shown in Embodiment 2. By performing such control by control device 200, as explained in Embodiments 1 and 2, it is possible to prevent a large amount of liquid refrigerant from accumulating in various locations in outdoor unit 12 when compressor 1 is not operating. This makes it possible to prevent the occurrence of liquid backflow, in which liquid refrigerant is drawn into compressor 1, when compressor 1 starts operating.

[0076] Fourth Embodiment In a fourth embodiment, another example of the arrangement of the first shutoff valve 8 and the second shutoff valve 9 will be described. Fig. 7 is a diagram showing the configuration of an air conditioning apparatus 10C according to the fourth embodiment.

[0077] Referring to Figure 7, the configuration of the air conditioning apparatus 10C differs from the above-mentioned embodiments 1 and 2 in that a first shut-off valve 8 is provided in the indoor unit 11 between the first heat exchanger 2 and the first extension pipe 6, and a second shut-off valve 9 is provided in the indoor unit 11 between the first heat exchanger 2 and the second extension pipe 7.

[0078] In the configuration of air conditioning apparatus 10C in Embodiment 4, first shutoff valve 8 and second shutoff valve 9 are controlled in the simultaneous shutoff mode shown in Embodiment 1 or the time-staggered shutoff mode shown in Embodiment 2. By performing such control by control device 200, as described in Embodiments 1 and 2, it is possible to prevent a large amount of liquid refrigerant from accumulating in various locations in outdoor unit 12 when compressor 1 is not operating. This makes it possible to prevent the occurrence of liquid backflow, in which liquid refrigerant is drawn into compressor 1, when compressor 1 starts operating.

[0079] Fifth Embodiment In a fifth embodiment, an example will be described in which a first shut-off valve 8 and a second shut-off valve 9 are provided in an air conditioning apparatus 10D that includes a plurality of devices, such as a first device 11a and a second device 11b, as indoor units 11. Figure 8 is a diagram showing the configuration of the air conditioning apparatus 10D of the fifth embodiment.

[0080] 8, as another example of a configuration in which the first shut-off valve 8 is provided in the indoor unit 11 and the second shut-off valve 9 is provided in the outdoor unit 12 as in Fig. 6, the configuration of an air conditioning apparatus 10D including multiple devices as the indoor unit 11 will be described as an example. Fig. 8 shows an example in which a first device 11a and a second device 11b are provided as the indoor unit 11. Note that when the indoor unit 11 includes multiple devices, three or more devices may be provided as the multiple devices.

[0081] Referring to Fig. 8, the first device 11a includes a first indoor heat exchanger 2a, a fan 20a, and a first shut-off valve 8a. The first indoor heat exchanger 2a is similar to the first heat exchanger 2 of the indoor unit 11 in Fig. 6. The fan 20a is similar to the fan 20 of the indoor unit 11 in Fig. 6. The first shut-off valve 8a is similar to the first shut-off valve 8 of the indoor unit 11 in Fig. 6. The first device 11a has a configuration as a single indoor unit.

[0082] Referring to Fig. 8, the second device 11b includes a second indoor heat exchanger 2b, a fan 20b, and a first shut-off valve 8b. The second indoor heat exchanger 2b is similar to the first heat exchanger 2 of the indoor unit 11 in Fig. 6. The fan 20b is similar to the fan 20 of the indoor unit 11 in Fig. 6. The first shut-off valve 8b is similar to the first shut-off valve 8 of the indoor unit 11 in Fig. 6. The second device 11b has a configuration as a single indoor unit.

[0083] Similar to the indoor unit 11 in Fig. 6, in the first refrigerant path 101 in Fig. 8, a first extension pipe 6 is provided in the first refrigerant path 101 between the expansion valve 3 of the outdoor unit 12 and the first shutoff valve 8a of the first device 11a. Similar to the indoor unit 11 in Fig. 6, in the second refrigerant path 102 in Fig. 8, a second extension pipe 7 is provided in the second refrigerant path 102 between the second shutoff valve 9 of the outdoor unit 12 and the first indoor heat exchanger 2a of the first device 11a.

[0084] In the first refrigerant path 101 in Fig. 8, a first extension pipe 60 branching off from the first extension pipe 6 is connected to the second device 11b. In the second refrigerant path 102 in Fig. 8, a second extension pipe 70 branching off from the second extension pipe 7 is connected to the second device 11b.

[0085] In the first refrigerant path 101 of Fig. 8, a first extension pipe 60 branching off from the first extension pipe 6 is provided between the expansion valve 3 of the outdoor unit 12 and the first shutoff valve 8b of the second device 11b. In the second refrigerant path 102 of Fig. 8, a second extension pipe 70 branching off from the second extension pipe 7 is provided between the second shutoff valve 9 of the outdoor unit 12 and the second indoor heat exchanger 2b of the second device 11b.

[0086] In the air conditioning apparatus 10D described above, which includes multiple devices such as the first device 11a and the second device 11b as the indoor units 11, the first shutoff valves 8a, 8b and the second shutoff valve 9 are controlled in the simultaneous shutoff mode described in embodiment 1 or the time-staggered shutoff mode described in embodiment 2. The first shutoff valves 8a, 8b are both controlled in the same manner as the first shutoff valve 8 described above. By performing this control by the control device 200, as described in embodiments 1 and 2, a large amount of liquid refrigerant is prevented from accumulating in various locations in the outdoor unit 12 when the compressor 1 is not operating. This makes it possible to prevent the occurrence of liquid backflow, in which liquid refrigerant is drawn into the compressor 1 when the compressor 1 starts operating.

[0087] Sixth Embodiment In a sixth embodiment, an example will be described in which a first shut-off valve 8 and a second shut-off valve 9 are provided in an air conditioning apparatus 10E that includes a plurality of devices, such as a first device 11c and a second device 11d, as indoor units 11. Figure 9 is a diagram showing the configuration of the air conditioning apparatus 10E of the sixth embodiment.

[0088] 9 illustrates another example of a configuration in which the indoor unit 11 is provided with a first shutoff valve 8 and a second shutoff valve 9, as in FIG. 7, and describes the configuration of an air conditioning apparatus 10E that includes multiple devices as the indoor unit 11. In FIG. 9, an example is shown in which a first device 11c and a second device 11d are provided as the indoor unit 11. Note that when the indoor unit 11 includes multiple devices, three or more devices may be provided as the multiple devices.

[0089] Referring to Fig. 9, the first device 11c includes a first indoor heat exchanger 2c, a fan 20c, a first shut-off valve 8c, and a second shut-off valve 9c. The first indoor heat exchanger 2c is similar to the first heat exchanger 2 of the indoor unit 11 in Fig. 7. The fan 20c is similar to the fan 20 of the indoor unit 11 in Fig. 7. The first shut-off valve 8c is similar to the first shut-off valve 8 of the indoor unit 11 in Fig. 7. The second shut-off valve 9c is similar to the second shut-off valve 9 of the indoor unit 11 in Fig. 7. The first device 11c has a configuration as a single indoor unit.

[0090] Referring to Fig. 9, the second device 11d includes a second indoor heat exchanger 2d, a fan 20d, a first shut-off valve 8d, and a second shut-off valve 9d. The second indoor heat exchanger 2d is similar to the first heat exchanger 2 of the indoor unit 11 in Fig. 7. The fan 20d is similar to the fan 20 of the indoor unit 11 in Fig. 7. The first shut-off valve 8d is similar to the first shut-off valve 8 of the indoor unit 11 in Fig. 7. The second shut-off valve 9d is similar to the second shut-off valve 9 of the indoor unit 11 in Fig. 7. The second device 11d has a configuration as a single indoor unit.

[0091] Similar to the indoor unit 11 in Fig. 7, in the first refrigerant path 101 in Fig. 9, a first extension pipe 6 is provided in the first refrigerant path 101 between the expansion valve 3 of the outdoor unit 12 and the first shutoff valve 8c of the first device 11c. Similar to the indoor unit 11 in Fig. 7, in the second refrigerant path 102 in Fig. 9, a second extension pipe 7 is provided in the second refrigerant path 102 between the flow path switching device 52 of the outdoor unit 12 and the second shutoff valve 9c of the first device 11c.

[0092] In the first refrigerant path 101 in Fig. 9, a first extension pipe 60 branching off from the first extension pipe 6 is connected to the second device 11d. In the second refrigerant path 102 in Fig. 9, a second extension pipe 70 branching off from the second extension pipe 7 is connected to the second device 11d.

[0093] In the first refrigerant path 101 of Fig. 9, a first extension pipe 60 branching off from the first extension pipe 6 is provided between the expansion valve 3 of the outdoor unit 12 and the first shutoff valve 8d of the second device 11d. In the second refrigerant path 102 of Fig. 9, a second extension pipe 70 branching off from the second extension pipe 7 is provided between the flow path switching device 52 of the outdoor unit 12 and the second shutoff valve 9d of the second device 11d.

[0094] In the air conditioning apparatus 10E including multiple devices such as the first device 11c and the second device 11d as the indoor units 11 as described above, the first shutoff valves 8c, 8d and the second shutoff valves 9c, 9d are controlled by the control device 200 in the simultaneous shutoff mode described in embodiment 1 or the time-staggered shutoff mode described in embodiment 2. The first shutoff valves 8c, 8d are both controlled in the same manner as the first shutoff valve 8 described above. The second shutoff valves 9c, 9d are both controlled in the same manner as the second shutoff valve 9 described above. By performing such control by the control device 200, as described in embodiments 1 and 2, accumulation of a large amount of liquid refrigerant in various locations in the outdoor unit 12 is suppressed when the compressor 1 is stopped. This makes it possible to suppress the occurrence of liquid backflow, in which liquid refrigerant is drawn into the compressor 1 when the compressor 1 starts operating.

[0095] Seventh Embodiment In a seventh embodiment, an example will be described in which the internal volume of the accumulator 51 is set to be less than the internal volume of the second heat exchanger 4.

[0096] As in conventional general air conditioners, when the amount of refrigerant circulating in the air conditioner increases due to the extension pipe being lengthened, and the accumulator becomes larger, the following problems may arise.

[0097] In a conventional general air conditioner, the internal volume of the accumulator is designed based on the amount of refrigerant to be sealed in the refrigerant circuit 100 when, for example, the length of the extension pipe is the maximum length within the design tolerance, so if the length of the extension pipe when installing the air conditioner is relatively short, the ratio of the amount of refrigerant flowing into the accumulator to the designed internal volume of the accumulator may be significantly smaller. In such a case, if the amount of refrigerant in the accumulator is too small, a phenomenon occurs in which the refrigerant stored in the accumulator while the compressor is stopped cannot immediately leave the accumulator when the compressor starts operating, resulting in a problem of a shortage of refrigerant being supplied to the compressor.

[0098] In the seventh embodiment, the internal volume of the accumulator 51 is set to be less than the internal volume of the second heat exchanger 4, thereby making the internal volume of the accumulator 51 relatively small, and an accumulator 51 is provided that can prevent a shortage of refrigerant supplied to the compressor 1 when the compressor 1 starts operating.

[0099] In the first to sixth embodiments, it has been explained that, in response to stopping the operation of the compressor 1, the control device 200 controls the first shut-off valve 8 (including 8a to 8d) to shut off the first refrigerant path 101 and the second shut-off valve 9 (including 9c, 9d) to shut off the second refrigerant path 102.

[0100] By performing such control, in the air conditioning apparatuses described above, such as the air conditioning apparatus 1, it is possible to suppress the amount of refrigerant stored in the outdoor unit 12 when the air conditioning apparatus is stopped, regardless of the lengths of the extension pipes such as the first extension pipe 6 and the second extension pipe 7, and therefore it is possible to suppress an increase in the internal volume of the accumulator 51. Therefore, as an example of setting the internal volume of the accumulator 51, it may be set to be less than the internal volume of the second heat exchanger 4, using the internal volume of the second heat exchanger 4 as a reference.

[0101] Next, a specific description will be given of the internal volume of the second heat exchanger 4. Fig. 10 is a diagram showing a schematic configuration of the second heat exchanger 4 according to embodiment 7. Fig. 10 shows, as a basic configuration example of the second heat exchanger 4, a schematic configuration of the second heat exchanger 4 in which the heat transfer tubes 25 through which the refrigerant flows are arranged in one row.

[0102] Fig. 10(A) is a front view of the second heat exchanger 4 as seen from the direction in which the fan 40 (the fan 40 in Fig. 1 etc.) is provided. Fig. 10(B) is a side view of the second heat exchanger 4 as seen from the direction of the inlet 26 and outlet 27 of the refrigerant in the second heat exchanger 4.

[0103] 10(A), the second heat exchanger 4 has heat transfer tubes 25 provided inside a frame member 28. The frame member 28 is provided with a large number of fins 29 for promoting heat exchange. In FIG. 10(A), the heat transfer tubes 25 inside the frame member 28 are omitted to avoid complicating the drawing.

[0104] 10(A) and 10(B), a refrigerant inlet 26 of the heat transfer tube 25 is provided at the top of the second heat exchanger 4. As shown in Figures 10(A) and 10(B), a refrigerant outlet 27 of the heat transfer tube 25 is provided at the bottom of the second heat exchanger 4. The heat transfer tube 25 includes a horizontal tube portion extending horizontally (left and right in the figure) inside the frame member 28 and a bent tube portion bent vertically (up and down in the figure) into a U-shape as shown at the left and right ends of the second heat exchanger 4 in Figure 10(A).

[0105] As shown in Figure 10 (B) , the heat transfer tube 25 has multiple stages of horizontal pipe sections arranged from the top to the bottom of the second heat exchanger 4, such as a first stage 251, a second stage 252, a third stage 253, a fourth stage 254, a fifth stage 255, a sixth stage 256, a seventh stage 257, and an eighth stage 258, and each horizontal pipe section is connected vertically by bent pipe sections at both the left and right ends of the second heat exchanger 4.

[0106] With this configuration, the heat transfer tube 25 extends in a serpentine shape, folding back and forth from the inlet 26 at the top of the second heat exchanger 4 to the outlet 27 at the bottom of the second heat exchanger 4 in the left-right direction of Figure 10 (A).

[0107] Referring to FIG. 10A, in the heat transfer tubes 25 of the second heat exchanger 4, the length EL of the range in which heat exchange occurs is called the stack width.

[0108] 11 is a side view of the second heat exchanger 4 in the seventh embodiment, in which the heat transfer tubes 25 are provided in two rows. In the second heat exchanger 4, the heat transfer tubes 25 may be provided in two or more rows.

[0109] 11 , the second heat exchanger 4 has two rows of heat transfer tubes 25, i.e., a first row 25 a and a second row 25 b. The first row 25 a and the second row 25 b of the heat transfer tubes 25 are connected to each other at a bent tube portion (not shown) present on the side surface opposite to the side surface of the second heat exchanger 4 shown in FIG.

[0110] With this configuration, the heat transfer tubes 25 extend in two rows from the inlet 26 at the top of the second heat exchanger 4 to the outlet 27 at the bottom of the second heat exchanger 4, turning back and forth in the left-right direction in Fig. 10(A) . Note that the heat transfer tubes 25 may be provided in three or more rows.

[0111] As described above, in the seventh embodiment, the internal volume of the accumulator 51 is specifically designed to be less than the internal volume of the second heat exchanger 4. The internal volume of the second heat exchanger 4 is the volume of the piping through which the refrigerant passes when heat is exchanged in the second heat exchanger. Generally, this internal volume can be calculated for the piping of the heat transfer tubes 25 of the second heat exchanger by the following calculation formula: [internal volume = cross-sectional area × stacking width × number of rows × number of columns].

[0112] The internal volume may be the volume of the heat transfer tube 25 through which the refrigerant passes in the second heat exchanger 4 in the range where heat exchange takes place, or it may be the sum of the volume of the heat transfer tube 25 in the range where heat exchange takes place and the volume of the heat transfer tube 25 in the range where heat exchange does not take place.

[0113] In embodiment 7, the internal volume of the accumulator 51 is set to be less than the internal volume of the second heat exchanger 4, thereby making it possible to make the internal volume of the accumulator 51 relatively small, and preventing a shortage of refrigerant supplied to the compressor 1 when the compressor 1 starts operating.

[0114] <Other Modifications> In an air conditioning apparatus such as the air conditioning apparatus 10, a first shut-off valve such as the first shut-off valve 8 may be provided at any location in the first refrigerant path 101 between the first heat exchanger 2 and the second heat exchanger 4, as long as the location does not impair the basic air conditioning function.

[0115] In an air conditioning apparatus such as air conditioning apparatus 10, a second shut-off valve such as second shut-off valve 9 may be installed anywhere in the second refrigerant path 102 between compressor 1 and first heat exchanger 2, as long as the location does not impair the basic air conditioning function.

[0116] In step S3 of FIG. 2, control is executed to simultaneously close the first shutoff valve 8 and the second shutoff valve 9, but specifically, the timing at which the first shutoff valve 8 is closed and the timing at which the second shutoff valve 9 is closed do not have to be completely simultaneous, and there may be some lag.

[0117] 5 shows a time-staggered shutoff mode in which the first shutoff valve 8 is controlled to a closed state at a first timing, and then the second shutoff valve 9 is controlled to a closed state at a second timing. In this time-staggered shutoff mode, the second timing at which the second shutoff valve 9 is controlled to a closed state may be set to any timing as long as it is a timing that can suppress the occurrence of liquid backflow when the compressor 1 starts operating.

[0118] Although an example in which the control device 200 is provided in the outdoor unit 12 has been described, the present invention is not limited to this, and the control device 200 may be provided in the indoor unit 11 .

[0119] In the fifth and sixth embodiments, in a configuration in which a first device such as first devices 11a and 11c and a second device such as second devices 11b and 11d are provided as indoor units 11, the positional relationship between the first and second shut-off valves may be as shown in FIG. 1 or as shown in FIG. 3.

[0120] (Summary) Hereinafter, the embodiment will be summarized with reference to the drawings again.

[0121] (Item 1) The present disclosure relates to an air conditioning apparatus (air conditioning apparatus 10, 10A, 10B, 10C, 10D, 10E). The air conditioner (air conditioner 10, 10A, 10B, 10C, 10D, 10E) includes an outdoor unit (outdoor unit 12), an indoor unit (indoor unit 11), a compressor (compressor 1) provided in the outdoor unit (outdoor unit 12) and compressing a refrigerant, a first heat exchanger (first heat exchanger 2) provided in the indoor unit (indoor unit 11) and exchanging heat between the refrigerant and indoor air, a second heat exchanger (second heat exchanger 4) provided in the outdoor unit (outdoor unit 12) and exchanging heat between the refrigerant and outdoor air, an expansion valve (expansion valve 3) provided in the outdoor unit (outdoor unit 12) and expanding the refrigerant in a first refrigerant path (first refrigerant path 101) between the first heat exchanger (first heat exchanger 2) and the second heat exchanger (second heat exchanger 4), and a valve (valve 4) provided in the first refrigerant path (first refrigerant path 102). a first shutoff valve (first shutoff valve 8, 8a, 8b, 8c, 8d) capable of shutting off a first refrigerant path (first refrigerant path 101) between the compressor (compressor 1) and the first heat exchanger (first heat exchanger 2); a second shutoff valve (second shutoff valve 9, 9c, 9d) capable of shutting off a second refrigerant path (second refrigerant path 102) between the compressor (compressor 1) and the first heat exchanger (first heat exchanger 2); and a control device (control device 200) that controls air conditioning, and in response to the compressor (compressor 1) being stopped, the control device (control device 200) controls the first shutoff valve (first shutoff valve 8, 8a, 8b, 8c, 8d) to shut off the first refrigerant path (first refrigerant path 101) and the second shutoff valve (second shutoff valve 9, 9c, 9d) to shut off the second refrigerant path (second refrigerant path 102) (see FIGS. 1 to 11, etc.).

[0122] (2) In the air conditioning apparatus described in 1, the control device (control device 200) controls the first refrigerant path (first refrigerant path 101) and the second refrigerant path (second refrigerant path 102) to be simultaneously blocked in response to the compressor (compressor 1) being stopped (see Figure 2, etc.).

[0123] (Clause 3) In the air conditioning apparatus described in Clause 1, the control device (control device 200) controls the first refrigerant path (first refrigerant path 101) to be blocked at a first timing in response to the compressor (compressor 1) stopping, and then controls the second refrigerant path (second refrigerant path 102) to be blocked at a second timing (see Figure 5, etc.).

[0124] (4) In the air conditioning apparatus described in any one of paragraphs 1 to 3, the first shut-off valve (first shut-off valve 8) and the second shut-off valve (second shut-off valve 9) are provided in the outdoor unit (outdoor unit 12) (see Figure 1, etc.).

[0125] (5) In the air conditioning apparatus described in any one of paragraphs 1 to 3, the first shut-off valve (first shut-off valve 8) is provided in the outdoor unit (outdoor unit 12), and the second shut-off valve (second shut-off valve 9) is provided in the indoor unit (indoor unit 11) (see Figure 3, etc.).

[0126] (Item 6) In the air conditioning apparatus described in any one of Items 1 to 3, the first shut-off valve (first shut-off valve 8) is provided in the indoor unit (indoor unit 11), and the second shut-off valve (second shut-off valve 9) is provided in the outdoor unit (outdoor unit 12) (see FIG. 6, etc.).

[0127] (Clause 7) In the air conditioning apparatus described in any one of clauses 1 to 3, the first shut-off valve (first shut-off valve 8) and the second shut-off valve (second shut-off valve 9) are provided in the indoor unit (indoor unit 11) (see Figure 7, etc.).

[0128] (8) In the air conditioning apparatus described in any one of paragraphs 1 to 7, an accumulator (accumulator 51) is provided in the outdoor unit (outdoor unit 12) and is capable of storing refrigerant to be supplied to the compressor (compressor 1), and the internal volume of the accumulator (accumulator 51) is less than the internal volume of the second heat exchanger (second heat exchanger 4) (see Figures 10 to 11, etc.).

[0129] (Item 9) In the air conditioning apparatus described in any one of Items 1 to 8, the first refrigerant path (first refrigerant path 101) includes a first extension pipe (first extension pipe 6) that extends the first refrigerant path (first refrigerant path 101) between the outdoor unit (outdoor unit 12) and the indoor unit (indoor unit 11), and the second refrigerant path (second refrigerant path 102) includes a second extension pipe (second extension pipe 7) that extends the second refrigerant path (second refrigerant path 102) between the outdoor unit (outdoor unit 12) and the indoor unit (indoor unit 11) (see Figures 1, 3, 4, 6, 7 to 9, etc.).

[0130] (Item 10) In the air conditioning apparatus described in Item 9, the indoor units (indoor units 11) include a first device (first devices 11a, 11c) provided with a first indoor heat exchanger (first indoor heat exchanger 2a, 2c) as the first heat exchanger (first heat exchanger 2), and a second device (second devices 11b, 11d) provided with a second indoor heat exchanger (second indoor heat exchanger 2b, 2d) as the first heat exchanger (first heat exchanger 2). The first refrigerant path (first refrigerant path 101) branches from the first extension pipe (first extension pipe 6) to the first device (first devices 11a, 11c) and the second device (first indoor heat exchangers 2a, 2c), and the second refrigerant path (second refrigerant path 102) branches from the second extension pipe (second extension pipe 7) to the first device (first devices 11a, 11c) and the second device (second devices 11b, 11d).

[0131] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0132] 12 outdoor unit, 11 indoor unit, 2 first heat exchanger, 4 second heat exchanger, 101 first refrigerant path, 8, 8a, 8b, 8c, 8d first shut-off valve, 1 compressor, 102 second refrigerant path, 9, 9c, 9d second shut-off valve, 200 control device, 10, 10A, 10B, 10C, 10D, 10E air conditioning device, 51 accumulator, 6 first extension pipe, 7 second extension pipe, 2a, 2c first indoor heat exchanger, 11a, 11c first device, 2b, 2d second indoor heat exchanger, 11b, 11d second device.

Claims

1. An air conditioning apparatus comprising: an outdoor unit; an indoor unit; a compressor provided in the outdoor unit for compressing a refrigerant; a first heat exchanger provided in the indoor unit for exchanging heat between the refrigerant and indoor air; a second heat exchanger provided in the outdoor unit for exchanging heat between the refrigerant and outdoor air; an expansion valve provided in the outdoor unit for expanding refrigerant in a first refrigerant path between the first heat exchanger and the second heat exchanger; a first shutoff valve capable of shutting off the first refrigerant path; a second shutoff valve capable of shutting off a second refrigerant path between the compressor and the first heat exchanger; and a control device for controlling air conditioning, wherein the control device controls the first shutoff valve to shut off the first refrigerant path and the second shutoff valve to shut off the second refrigerant path in response to the compressor being stopped.

2. The air-conditioning apparatus according to claim 1, wherein the control device performs control to simultaneously shut off the first refrigerant path and the second refrigerant path in response to the compressor being stopped.

3. An air conditioning apparatus as described in claim 1, wherein the control device, in response to the compressor being stopped, controls the first refrigerant path to be blocked at a first timing, and then blocks the second refrigerant path at a second timing.

4. An air-conditioning apparatus as described in any one of claims 1 to 3, wherein the first shut-off valve and the second shut-off valve are provided in the outdoor unit.

5. An air conditioning apparatus as described in any one of claims 1 to 3, wherein the first shut-off valve is provided in the outdoor unit, and the second shut-off valve is provided in the indoor unit.

6. An air-conditioning apparatus as claimed in any one of claims 1 to 3, wherein the first shut-off valve is provided in the indoor unit, and the second shut-off valve is provided in the outdoor unit.

7. An air conditioning apparatus as described in any one of claims 1 to 3, wherein the first shutoff valve and the second shutoff valve are provided in the indoor unit.

8. An air-conditioning apparatus as described in any one of claims 1 to 7, further comprising an accumulator provided in the outdoor unit and capable of storing refrigerant to be supplied to the compressor, wherein the internal volume of the accumulator is less than the internal volume of the second heat exchanger.

9. An air conditioning apparatus as described in any one of claims 1 to 8, wherein the first refrigerant path includes a first extension pipe that extends the first refrigerant path between the outdoor unit and the indoor unit, and the second refrigerant path includes a second extension pipe that extends the second refrigerant path between the outdoor unit and the indoor unit.

10. The air conditioning apparatus of claim 9, wherein the indoor unit includes a first device having a first indoor heat exchanger as the first heat exchanger, and a second device having a second indoor heat exchanger as the first heat exchanger, the first refrigerant path branches from the first extension pipe to the first device and the second device, and the second refrigerant path branches from the second extension pipe to the first device and the second device.

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