JPH0611208A - Air conditioner - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] When restarting after an operation stop, an air conditioner that can be restarted in a stable state without causing heat loss or wet operation. [Composition] A compressor 1, an oil recovery unit 2, a four-way valve 3, a utilization side heat exchanger 4, a liquid receiver 5, a heat source side heat exchanger 6 having a fan 61, an accumulator 7, and an expansion 8 capable of fully opening, In a system in which a pressure equalizing circuit 11 having a pressure equalizing valve 10 is provided between the suction side of the compressor 1 and the liquid receiver 5, the pressure equalizing valve 10 when the compressor 1 is stopped and the expansion valve 8 is opened after a certain time has elapsed. The pressure equalizing valve 1 is provided with a control means 15 that fully closes the valves 10 and 8 during pressure equalizing.
The pressure is equalized by the opening operation of 0, and by opening the expansion valve 8 until the pressure equalizes, the inside of the heat exchanger 4 on the side of use, which is the evaporator during cooling, and the heat exchanger 6 on the heat source side, which serves as the evaporator during heating. After the liquid refrigerant is collected in the liquid receiver 5, the pressure equalizing valve 10 and the expansion valve 8 are fully closed when the pressure equalizing state is reached, so that the liquid refrigerant can be safely started even in the state where it is left stopped for a long time in the low outside air in winter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, more specifically, a compressor, a utilization side heat exchanger, a liquid receiver, an expansion valve and a heat source side air heat exchanger. The present invention relates to an air conditioner provided with a pressure equalizing circuit having a pressure equalizing valve between the liquid receiver and the liquid receiver.

[0002]

2. Description of the Related Art Conventionally, as this type of air conditioner, a four-way switching valve, a utilization side heat exchanger, a receiver, an expansion valve and a heat source side air heat exchanger are connected to the refrigerant discharge side of a compressor. ,Air conditioning,
What can be heated is, for example, the actual fair 2-3605.
It is already known in the publication No. 9.

However, in a general air conditioner, as shown in FIG. 3, an oil recovery unit B, a four-way switching valve C, a use side heat exchanger D, are provided on the refrigerant discharge side of the compressor A. The liquid receiver E, the heat source side air heat exchanger F and the accumulator G are respectively connected to form a refrigeration cycle, and the first expansion valve H and the first expansion valve H are provided between the use side heat exchanger D and the liquid receiver E. 1 Check valve I, and the receiver E and the heat source side air heat exchanger F
A second expansion valve J and a second check valve K are connected in parallel with each other, and a pressure equalizing circuit M having a pressure equalizing valve L is provided between the liquid receiver E and the accumulator G. ing. In the figure, N is a superheat detector provided on the refrigerant discharge side during the cooling operation of the use side heat exchanger D, and during the cooling operation, the first expansion valve H of the first expansion valve H is detected based on the detection result by the detector N. The degree of opening is adjusted to control the superheat degree, and O is a superheat detector provided on the refrigerant discharge side of the heat source side air heat exchanger F during the heating operation. The degree of superheat is controlled by adjusting and controlling the opening degree of the second expansion valve J based on the detection result of the detector O. Further, P is a suction filter provided on the suction side of the compressor A.

When performing the cooling operation in the above air conditioner, as shown by the dotted arrow in the figure, the compressor A → oil collector B → four-way switching valve C → heat source side air heat exchange Bowl F
→ second check valve K → receiver E → first expansion valve H → use side heat exchanger D → four-way switching valve C → accumulator G → suction filter P → refrigerant is circulated in the path of compressor A, The heat source side air heat exchanger F is used as a condenser, the use side heat exchanger D is used as an evaporator, and indoor cooling is performed with the low temperature liquid taken out from the use side heat exchanger D. During the above cooling operation, the first expansion valve H is used, and the degree of opening of the first expansion valve H is adjusted based on the detection result of the detector N to control the degree of superheat.

During the heating operation, as shown by the solid arrow in the figure, the compressor A → the oil recovery device B → the four-way switching valve C →
Use side heat exchanger D → first check valve I → liquid receiver E → second expansion valve J → heat source side air heat exchanger F → four-way switching valve C → accumulator G → suction filter P → compressor A Refrigerant is circulated in the path, the heat source side air heat exchanger F is used as an evaporator, the use side heat exchanger D is used as a condenser, and the high temperature liquid taken out from the use side heat exchanger D is used as a chamber. The inside is heated. During the above heating operation, the second expansion valve J is used, and the degree of opening is adjusted based on the detection result of the detector O to control the degree of superheat.

Further, when the operation is stopped during the cooling and heating operation as described above, the pressure equalizing valve L provided in the pressure equalizing circuit M is opened, and the accumulator provided on the suction side of the compressor A. G and the receiver E are pressure-equalized, and this pressure equalization facilitates starting of the compressor A. Further, the pressure equalization is performed by opening the pressure equalization valve L for a certain period of time. 2 Hold the expansion valves H and J fully closed,
Utilization side heat exchanger D that has a low pressure during operation from the receiver
Further, the refrigerant is prevented from flowing into the heat source side air heat exchanger F. After a certain period of time, the first and second expansion valves H and J are fully opened, and the refrigerant remaining in the use side heat exchanger D or the heat source side air heat exchanger F is transferred to the receiver E side. I try to collect it.

[0007]

However, when the air conditioner configured as described above is used in a building, the heat source side air heat exchanger F is installed at a high place such as a rooftop,
In addition, the compressor A, the receiver E, the accumulator G, etc.
For example, since it is arranged in a machine room provided in a basement or the like, the compressor A is stopped from the heating operation state as described above under low outside air conditions such as winter, and after the pressure equalization, the pressure equalizing valve L and If the second expansion valve J is left open for a long period of time, the heat source side air heat exchanger F is placed at a high place outdoors exposed to low outside air, and the pressure equalizing valve L is opened. Therefore, the refrigerant is sequentially condensed and liquefied in the heat source side air heat exchanger F, the liquid refrigerant is returned to the liquid receiver E side, and the liquid receiver E is cooled by the return of the liquid refrigerant. There was a problem that caused heat loss. Moreover, when the high temperature liquid refrigerant flows into the liquid receiver E in which the low temperature liquid refrigerant is accumulated at the time of starting, the internal temperature of the liquid receiver E becomes unstable, and the liquid receiver E becomes High and low temperature refrigerant may flow to the second expansion valve J and the heat source side air heat exchanger F side, and the opening control of the second expansion valve J by the detector O may become unstable, leading to wet operation. That is, at startup, for example, a high temperature refrigerant is supplied from the liquid receiver E to the second expansion valve J and the heat source side air heat exchanger F side, and the superheat degree at the outlet of the heat source side air heat exchanger F is large. In this case, the opening degree of the second expansion valve J is adjusted to a large degree by the detector O, but in this state, if a large amount of low-temperature refrigerant flows from the liquid receiver E, the heat source side air Since the evaporation capacity of the heat exchanger F is constant, the superheat at the outlet of the heat source side air heat exchanger F Is rapidly lowered, and thus lead to wet operation in the compressor A, there is a problem that can not be started in a stable state. This problem also occurs when the cooling operation is performed, and the degree of superheat at the outlet of the use side heat exchanger D becomes unstable at the time of starting, resulting in a wet operation.

The present invention has been made in view of the above problems, and an object thereof is to start the engine in a stable state without causing heat loss or wet operation when the engine is stopped and then started. It is to provide an air conditioner capable of

[0009]

To achieve the above object, the present invention provides a compressor 1, a utilization side heat exchanger 4, a heat source side air heat exchanger 6 provided with a fan 61, and a liquid receiver 5. And an expansion valve 8 which can be fully closed, and an air conditioner having a pressure equalizing circuit 11 having a pressure equalizing valve 10 between the suction side of the compressor 1 and the liquid receiver 5, When the operation is stopped, the pressure equalizing valve 10 is first opened, the expansion valve 8 is also opened after a certain period of time, and after the pressure equalization is completed, the pressure equalizing valve 10 and the expansion valve 8 are fully closed. is there.

As the valve control means, a pressure equalizing detector 16 for detecting the differential pressure between the high pressure side pressure and the low pressure side pressure and detecting the pressure equalizing state is used. Based on the detection result of the pressure equalizing detector 16. It is preferable that the pressure equalizing valve 10 and the expansion valve 8 are fully closed.

As the valve control means, the compressor 1
Is stopped, the time is counted and after a certain period of time, the pressure equalizing valve 1
A timer 19 that outputs 0 and a fully closed command to fully close the expansion valve 8 may be used.

[0012]

In the above air conditioner, the pressure equalizing valve 1 installed in the pressure equalizing circuit 11 by the valve control means when the operation is stopped.
0 is opened, the suction side of the compressor 1 and the liquid receiver 5 are pressure-equalized, and the pressure is equalized by the opening operation of the pressure equalization valve 10, and the expansion valve 8 is also opened after a lapse of a certain time. Then, the liquid refrigerant in the use-side heat exchanger 4 that serves as an evaporator during cooling and the heat-source-side air heat exchanger 6 that serves as an evaporator during heating is recovered to the receiver 5 side. Then, when the suction side of the compressor 1 and the liquid receiver 5 are equalized with a predetermined pressure difference, the equalizing valve 10 and the expansion valve 8 are fully closed by the valve control means. When the heating operation is performed under low outside air conditions such as in winter, even if the heating operation is stopped and left for a long time, the refrigerant flow between the heat source side air heat exchanger 6 and the liquid receiver 5 remains. Due to this refrigerant flow, the refrigerant condensed and liquefied in the heat source side air heat exchanger 6 is not returned to the receiver 5 side, and the receiver 5 is cooled by the reflux refrigerant. Heat loss can be prevented. That is, the heat source side air heat exchanger 6 is arranged outdoors such as on a rooftop exposed to low temperatures, while the liquid receiver 5 is arranged in a machine room such as a basement room where the temperature is higher than outdoors. Therefore, when the heating operation is stopped and the pressure equalizing valve 10 and the expansion valve 8 are left open for a long time, the gas refrigerant from the liquid receiver 5 is discharged from the pressure equalizing valve 1
The liquid refrigerant that has flowed into the heat source side air heat exchanger 6 via 0 and is condensed and condensed returns to the liquid receiver 5 via the expansion valve 8 to form a thermocycle.
Although the temperature of the liquid refrigerant of No. 2 decreases and heat loss occurs, the heating cycle is stopped because the thermocycle is not generated after the pressure equalization by closing the pressure equalization valve 10 and the expansion valve 8 during the pressure equalization. Even if the liquid refrigerant is left for a long time, the liquid refrigerant does not flow back to the liquid receiver 5, so that the liquid refrigerant in the liquid receiver 5 becomes low in temperature and heat loss can be prevented from occurring.

Further, there are cases where the cooling operation is carried out under low outside air conditions such as in a computer room such as in the winter, but when the cooling operation is stopped, the pressure equalizing valve is stopped after the cooling operation is stopped due to the temperature difference between the outside and the room. When the valve 10 and the expansion valve 8 are left open for a long time, the thermocycle in which the refrigerant condensed from the use side air heat exchanger 6 is returned to the liquid receiver 5 is formed, and the liquid in the liquid receiver 5 is formed. Although the temperature of the refrigerant will decrease, by closing the pressure equalizing valve 10 and the expansion valve 8 during pressure equalization, even if the cooling operation is stopped and left for a long time, the thermocycle causes the liquid receiver 5 It is possible to prevent the temperature of the liquid refrigerant from becoming low.

Therefore, heat loss due to cooling of the liquid receiver 5 with the reflux refrigerant can be prevented, and the internal temperature of the liquid receiver 5 becomes unstable at the time of starting, so that the expansion valve 8
It is possible to prevent instability of the opening control of, and to prevent wet operation.

As the valve control means, a pressure equalizing detector 16 for detecting the pressure difference between the high pressure side pressure and the low pressure side pressure to detect the pressure equalizing state is used. When the pressure equalizing valve 10 and the expansion valve 8 are configured to be fully closed based on the above, the suction side of the compressor 1 and the liquid receiver 5
Since the pressure equalization state is detected by the pressure difference between the pressure equalization and the pressure equalization state, the pressure equalization state can be accurately detected. Therefore, the fully closing operation of the pressure equalization valve 10 and the expansion valve 8 at the time of pressure equalization can be reliably and accurately performed. By doing so, the engine can be started in a stable state without causing heat loss or wet operation.

Further, as the valve control means, there is provided a timer 19 which counts time when the compressor 1 is stopped and outputs a fully closed command to fully close the pressure equalizing valve 10 and the expansion valve 8 after a certain time. When used, the timer 19
The output from the device can surely perform the full closing operation of the pressure equalizing valve 10 and the expansion valve 8, and can be started in a stable state without causing heat loss or wet operation while using an inexpensive timer. You can

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a separate type heat pump type air conditioner, which basically has the same structure as that of a conventional one, and includes a compressor 1, an oil recovery unit 2 and 4. A path switching valve 3, a utilization side heat exchanger 4, a liquid receiver 5, a heat source side air heat exchanger 6 provided with a plurality of fans 61, an accumulator 7, and an expansion valve 8 capable of being fully closed,
A refrigeration cycle is formed by each of these persons. The compressor 1, the oil recovery unit 2, the four-way switching valve 3, the use side heat exchanger 4, the liquid receiver 5, the accumulator 7, and the expansion valve 8 are arranged in a machine room such as a basement, while The heat source side air heat exchanger 6 is arranged outdoors, for example, on the rooftop.

The expansion valve 8 includes a first expansion valve 8A interposed between the utilization side heat exchanger 4 and the liquid receiver 5.
The second expansion valve 8B is interposed between the liquid receiver 5 and the heat source side air heat exchanger 6, and the first and second expansion valves 8A and 8B are respectively provided with a second expansion valve 8B. The first and second check valves 9A and 9B are provided in parallel. Further, between the liquid receiver 5 and the accumulator 7, a pressure equalizing valve 10 for equalizing the pressure on the accumulator 7 side and the liquid receiver 5 side when the operation of the compressor 1 is stopped during the cooling and heating operations. The interposed equalizing circuit 11 is connected. In the figure, reference numeral 12 is a superheat degree detector provided on the refrigerant discharge side of the use side heat exchanger 4 during the cooling operation, and during the cooling operation, the first expansion valve 8A of the first expansion valve 8A is detected based on the detection result by the detector 12. The opening degree is adjusted and controlled to control the degree of superheat.
Is a superheat detector provided on the refrigerant discharge side during the heating operation of the heat source side air heat exchanger 6, and adjusts the opening degree of the second expansion valve 8B based on the detection result of the detector 13 during the heating operation. The superheat degree is controlled by controlling.
Reference numeral 14 is a suction filter provided on the suction side of the compressor A.

When performing the cooling operation in the above air conditioner, as shown by the dotted arrow in the figure, the compressor 1 → oil collector 2 → 4 way switching valve 3 → heat source side air heat exchange Bowl 6
→ second check valve 9B → receiver 5 → first expansion valve 8A → use side heat exchanger 4 → 4 way switching valve 3 → accumulator 7 → intake filter 14 → refrigerant is circulated in the path of the compressor 1, The heat source side air heat exchanger 6 is a condenser, and the use side heat exchanger 4 is an evaporator, so that the indoor side cooling is performed by the low temperature liquid taken out from the use side heat exchanger 4. Be seen. During the above cooling operation, the second expansion valve 8B is not used and is kept in the closed state, the first expansion valve 8A is used, and the opening degree is determined based on the detection result of the detector 12. By adjusting, superheat control is performed.

During the heating operation, as shown by the solid line arrow in the figure, the compressor 1 → the oil recovery device 2 → the four-way switching valve 3 →
Use side heat exchanger 4 → first check valve 9A → liquid receiver 5 → second expansion valve 8B → heat source side air heat exchanger 6 → four-way switching valve 3 → accumulator 7 → suction filter 14 → compressor 1 Refrigerant is circulated in the path, the heat source side air heat exchanger 6 is used as an evaporator, the use side heat exchanger 4 is used as a condenser, and the high temperature liquid extracted from the use side heat exchanger 4 is used as a chamber. The inside is heated. Incidentally, during the above heating operation, the first expansion valve 8A
Is maintained in a closed state without being used, the second expansion valve 8B is used, and the degree of superheat is controlled by adjusting the opening degree based on the detection result of the detector 13.

In the above air conditioner, however, when the compressor 1 is stopped during the cooling and heating operations, the pressure equalizing valve 10 is opened immediately after the stop, and the high and low differential pressure has a predetermined differential pressure ( For example, when the pressure becomes ² Kg / cm ² ), the first and second expansion valves 8A and 8B are opened next, and at the time of pressure equalization, the pressure equalization valve 10 and the first and second expansion valves 8A and 8B are fully closed. The means 15 is provided.

Specifically, as shown in FIG. 1, a difference in height between the liquid receiver 5 and the accumulator 7 is detected, and the difference pressure is determined to be a predetermined difference pressure (eg, 0.5
(Kg / cm ² or less), a pressure equalizing detector 16 for detecting the pressure equalizing state when the pressure equalizing state is reached is provided, and a controller 17 having the pressure equalizing detector 16 connected to the input side is provided. The valve control means 15 is constituted by the pressure equalizing detector 16 and the controller 17, and the pressure equalizing valve 10 and the first valve are provided at the output section 18 of the controller 17.
And the second expansion valves 8A and 8B, and when the controller 17 receives an operation stop signal, the controller 17
According to the instruction, when the operation is stopped, the pressure equalizing valve 10 is opened and the first and second expansion valves 8A and 8B are fully closed, and then the differential pressure between the liquid receiver 5 and the accumulator 7 becomes the predetermined differential pressure. Just before the pressure equalization state is reached, the first and second expansion valves 8
A and 8B are opened, and the pressure equalizing detector 16 is provided.
When the pressure equalizing state is detected, a fully closed command is output from the output unit 18 of the controller 17 to the pressure equalizing valve 10 and the first and second expansion valves 8A and 8B by the input from the detector 16. , It is configured to control each of these persons to a fully closed state.

Then, when the operation of the compressor 1 is stopped in the heating operation by the above air conditioner, first, by the output from the controller 17,
While opening the pressure equalizing valve 10, the first and second expansion valves 8A,
8B is fully closed, and the refrigerant remaining in the heat source side air heat exchanger 6 at the time of stop is supplied with the first and second expansion valves 8A after a predetermined time, that is, shortly before the detector 16 detects the pressure equalized state. , 8B
Is opened and collected in the liquid receiver 5.

Next, by the opening operation of the pressure equalizing valve 10, the suction side of the compressor 1, that is, the accumulator 7 side and the liquid receiver 5 side become a predetermined differential pressure and the pressure is equalized. When a pressure state is detected by the pressure equalizing detector 16, the pressure equalizing valve 10 and the first pressure regulating valve 10 are output from the output unit 18 of the controller 17.
And the second expansion valves 8A, 8B are fully closed, and the respective valves 10, 8A, 8B are fully closed, so that the valves 10, 8A, 8B remain open for a long time after the stop. When left unattended, the thermocycle that occurs due to the temperature difference between the machine room and the outdoors does not occur. Therefore, the refrigeration of the low temperature refrigerant from the heat source side air heat exchanger 6 to the liquid receiver 5 side is prevented by the thermocycle, so that the heat loss due to the liquid receiver 5 being cooled by the reflux refrigerant. In addition, since the internal temperature of the liquid receiver 5 does not become unstable at the time of start-up, the opening control of the second expansion valve 8B by the superheat detector 13 becomes unstable and wet operation is performed. Inviting people can also be prevented.

As the valve control means 15, FIG.
As shown in, when the operation of the compressor 1 is stopped, the time is counted, and after a certain period of time (for example, after a lapse of 15 minutes to reach a pressure equalizing state), the pressure equalizing valve 10 and the first and second expansion valves 8
A controller 20 having a timer 19 for outputting a fully closed command to A and 8B is used, and the pressure equalizing valve 10 and each expansion valve 8 are controlled by the controller 20 having such a timer 19.
You may make it control A and 8B.

In this case, when the operation of the compressor 1 is stopped, the pressure equalizing valve 10 is first opened by the output from the controller 20, and the expansion valves 8A and 8B are opened.
When the timer 19 counts, for example, about 10 minutes after the operation is stopped, the expansion valves 8A and 8B are opened by the output from the controller 20, and the liquid condensed in the heat source side air heat exchanger 6 is closed. The refrigerant is collected on the liquid receiver 5 side.

Next, when the timer 19 counts about 15 minutes, the pressure equalizing valve 10 and the expansion valves 8A and 8B are fully closed by the output from the controller 20. Refrigerant having a low temperature from the heat source side air heat exchanger 6 to the liquid receiver 5 side is prevented from flowing back by the thermocycle, so that heat loss and wet operation are not caused while using an inexpensive timer. , Can be started in a stable state.

[0028]

As described above, according to the present invention, the compressor 1, the utilization side heat exchanger 4, the heat source side air heat exchanger 6 provided with the fan 61, the liquid receiver 5 and the fully-closed type are possible. Expansion valve 8
An air conditioner having a pressure equalizing circuit 11 having a pressure equalizing valve 10 between the suction side of the compressor 1 and the liquid receiver 5, and the pressure equalizing valve when the compressor 1 is stopped. 10
When the pressure difference between the high and low reaches a predetermined pressure difference or after a certain time has elapsed after the pressure difference is stopped, the expansion valve 8 is opened to equalize the pressure during the equalization.
0 and the valve control means for fully closing the expansion valve 8 are provided, so that when the operation is stopped, the valve control means opens the pressure equalizing valve 10 interposed in the pressure equalizing circuit 11 so that the suction side of the compressor 1 is connected. The pressure of the liquid receiver 5 is equalized, and the equalization valve 1
The pressure is equalized by the opening operation of 0, the expansion valve 8 is also opened after a lapse of a fixed time, and the utilization side heat exchanger 4 serving as an evaporator during cooling is provided.
The liquid refrigerant in the heat-source-side air heat exchanger 6, which serves as an evaporator during heating, is recovered by the liquid receiver 5 side. And the compressor 1
When the suction side and the liquid receiver 5 are equalized to have a predetermined differential pressure, the valve control means fully closes the equalization valve 10 and the expansion valve 8. Therefore, for example, in a low outside air condition such as in winter. Even if the heating operation is stopped for a long time when the heating operation is performed, the refrigerant condensed and liquefied in the heat source side air heat exchanger 6 is returned to the receiver 5 side. Therefore, heat loss due to the liquid receiver 5 being cooled by the reflux refrigerant can be prevented. Therefore, it is possible to prevent the control of the opening degree of the expansion valve 8 from becoming unstable due to the instability of the internal temperature of the liquid receiver 5 at the time of starting, and it is possible to prevent a wet operation. When the cooling operation is stopped, the refrigerant condensed and liquefied in the heat source side air heat exchanger 6 can be prevented from being returned to the liquid receiver 5 side as in the case of stopping the heating operation. .

As the valve control means, a pressure equalizing detector 16 for detecting the pressure difference between the high pressure side pressure and the low pressure side pressure to detect the pressure equalizing state is used. When the pressure equalizing valve 10 and the expansion valve 8 are configured to be fully closed based on the above, the suction side of the compressor 1 and the liquid receiver 5
Since the pressure equalization state is detected by the pressure difference between the pressure equalization and the pressure equalization state, it is possible to accurately detect the pressure equalization state. Therefore, it is possible to reliably perform the fully closing operation of the pressure equalization valve 10 and the expansion valve 8 during the pressure equalization. , Without causing heat loss or damp driving,
It can be started in a stable state.

Further, as the valve control means, a timer 19 for counting the time when the compressor 1 is stopped and outputting a fully closed command to fully close the pressure equalizing valve 10 and the expansion valve 8 after a certain time has passed. When used, the timer 19
The output from the device can surely perform the full closing operation of the pressure equalizing valve 10 and the expansion valve 8, and can be started in a stable state without causing heat loss or wet operation while using an inexpensive timer. You can

[Brief description of drawings]

FIG. 1 is a refrigeration piping diagram showing an air conditioner according to the present invention.

FIG. 2 is a refrigeration piping diagram showing another embodiment of the air conditioner.

FIG. 3 is a refrigeration piping diagram showing an air conditioner according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 4 Utilization side heat exchanger 5 Liquid receiver 6 Heat source side air heat exchanger 61 Fan 8 Expansion valve 10 Pressure equalizing valve 11 Pressure equalizing circuit 16 Pressure equalizing detector 18 Output section 19 Timer

Claims (3)

[Claims] 1. A compressor 1, a utilization-side heat exchanger 4, a heat-source-side air heat exchanger 6 provided with a fan 61, a liquid receiver 5, and an expansion valve 8 that can be fully closed. In the air conditioner in which a pressure equalizing circuit 11 having a pressure equalizing valve 10 is provided between the suction side of No. 1 and the liquid receiver 5, the pressure equalizing valve 10 and the high and low differential pressure are set to a predetermined value when the compressor 1 is stopped. An air conditioner characterized by comprising valve control means for opening the expansion valve 8 when a pressure difference is reached or after a lapse of a certain time after stoppage, and fully closing the pressure equalization valve 10 and the expansion valve 8 during pressure equalization. apparatus. 2. A pressure equalizing detector 16 for detecting a differential pressure between a high pressure side pressure and a low pressure side pressure to detect a pressure equalizing state.
The air conditioner according to claim 1, further comprising: an output unit 18 that fully closes the pressure equalizing valve 10 and the expansion valve 8 based on a result of the pressure equalizing detector 16. 3. The valve control means, when the operation of the compressor 1 is stopped,
Time is counted and after a certain time, the pressure equalizing valve 10 and the expansion valve 8
The air conditioner according to claim 1, further comprising a timer 19 that outputs a fully closed command to fully close the air conditioner.