JP2000249436A - Air conditioner equipped with ice thermal storage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling operation by a method wherein an oil content separating tank of the suction side of a small-size compressor is provided with a sensor to switch refrigerant, which flows into a surge tank, so that a surge tank, connected to the discharging side of the small-size compressor, is filled with much amount of liquid refrigerant while another surge tank, connected to the suction side of the small-size compressor, is filled with small amount of liquid refrigerant. SOLUTION: A sensor and an oil content separating tank 35 are arranged at the suction port of a small-size compressor 36 while a control unit 40 reads an information, detected by the sensor of the oil content separating tank 35. When either one of a surge tank 25 or another surge tank 25B is filled with refrigerant liquid, a switching valve 34 is switched. When the switching valve 34 is switched to the side of a flow passage A, high-pressure gas refrigerant flows into the surge tank 25 from the small- size compressor 36. When the sensor of the oil constituent separating tank 35 has detected the refrigerant liquid and the switch 34 is switched to the side of another flow passage B, high-pressure gas refrigerant, discharged out of the small-size compressor 36, is guided into the other surge tank 25B through a refrigerant pipe 29 and another refrigerant pipe 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having an ice heat storage tank, and more particularly to an air conditioner having an ice heat storage tank which performs cooling and cooling operation by radiating cold stored in an ice heat storage unit. About.

[0002]

2. Description of the Related Art Generally, as shown in FIG.
A heat source side unit 5 including a heat source side heat exchanger 2, a four-way valve 3 and an expansion valve 4, and a refrigerant pipe 7 disposed in a submerged state in an ice heat storage tank 6 to generate ice on the outer periphery of the refrigerant pipe 7 There is known an air conditioner 10 that performs an ice heat storage operation, a cooling / cooling operation, and a normal cooling operation by combining an ice heat storage unit 8 that stores heat with a use-side heat exchanger 9.

[0003] In the ice heat storage operation, the gas refrigerant from the compressor 1 becomes a liquid refrigerant through the heat source side heat exchanger 2 and then flows into the refrigerant pipe 7 in the ice heat storage tank 6 through the expansion valve 4. The gas refrigerant evaporates while performing the ice heat storage operation in the ice heat storage tank 6, and the gas refrigerant is returned to the compressor 1.

In the cooling / cooling operation, the compressor 1 of the heat source side unit 5 is stopped, and a circulating pump 11 such as a liquid pump or a gas pump installed in the ice heat storage unit 8 for pumping the refrigerant.
(In FIG. 2, a liquid pump for pumping the liquid refrigerant is operated). That is, by the operation of the circulation pump 11, the cold heat stored in the ice is radiated to the refrigerant in the refrigerant pipe 7 of the ice heat storage tank 6 of the ice heat storage unit 8, and the liquid refrigerant thus absorbed and condensed by the cold heat Is sent to the use-side heat exchanger 9, and the liquid refrigerant evaporates in the use-side heat exchanger 9 to perform the cooling / cooling operation.

In the normal cooling operation, the refrigerant which is guided from the compressor 1 to the heat source side heat exchanger 2 and becomes a liquid refrigerant passes through the refrigerant pipe 7 of the ice heat storage tank 6 to the use side heat exchanger 9. The supplied liquid refrigerant evaporates here, and cooling is performed by the latent heat of evaporation.

[0006]

In the cooling / cooling operation described above, particularly when the circulating pump 11 is a liquid pump, when the refrigerant is not completely condensed and some refrigerant gas is present, the circulating pump 11 Cavitation may occur. Therefore, without using this liquid pump, a plurality (for example, 2) of condensed liquid refrigerant in the refrigerant pipe 7 of the ice heat storage tank 6 is used.
Are stored in the surge tanks 25 and the high-pressure gas refrigerant is alternately supplied into the surge tanks 25 by the small compressor 36 (gas pump), so that the liquid refrigerant condensed in the surge tank 25 is used. It is conceivable to perform the cooling / cooling operation by feeding the pressure to the side heat exchanger 9.

However, in this case, the small compressor 36 performs an operation of sucking refrigerant gas from another surge tank 25 while supplying high-pressure gas refrigerant into one surge tank 25. If the oil return mechanism is not provided, poor lubrication of the small compressor 36, abnormal wear and seizure may occur.

The present invention has been made in view of such circumstances, and has a small compressor 36 provided with an oil return mechanism.
It is an object of the present invention to provide an air conditioner provided with an ice heat storage tank that can perform a cooling operation using cold heat of ice in the ice heat storage tank.

[0009]

According to the first aspect of the present invention,
A heat source side unit including a compressor and a heat source side heat exchanger,
An ice heat storage unit including a device that forms ice in an ice heat storage tank to store heat, a plurality of surge tanks for storing liquid refrigerant, a small compressor, and the like, and a use-side heat exchanger to perform ice heat storage operation and cooling. In an air conditioner that is operated, a small compressor having a smaller capacity than the compressor of the heat source side unit, a switching valve, a surge tank, a use side heat exchanger, and equipment forming ice are connected by a refrigerant pipe. A refrigeration cycle utilizing ice heat storage is constructed, an oil separation tank is provided on the suction side of the small compressor, and a sensor is provided on this oil separation tank.The sensor is used to change the liquid state of the surge tank connected to the suction side of the small compressor. The refrigerant flowing through the surge tank is switched by the switching valve so that the surge tank with a large amount of liquid refrigerant is on the discharge side of the small compressor and the surge tank with little liquid refrigerant is on the suction side of the small compressor, and In which the switching valve is adapted to open the on-off valve provided in the oil outlet once oil separation tank each time switched a plurality of times.

According to a second aspect of the present invention, in the air conditioner having the ice heat storage tank according to the first aspect, a small heat exchanger is provided between an on-off valve of an oil separation tank and a suction port of a small compressor. The small heat exchanger is characterized in that the refrigerant discharged from the small compressor exchanges heat with the refrigerant rich in oil separated in the oil separation tank.

According to the first and second aspects of the present invention, the oil separation tank and the sensor are provided on the suction side of the small compressor, and when the refrigerant liquid is detected by this sensor, a plurality of surge tanks are provided. It is determined that the liquid refrigerant in any one of the tanks is almost full. If one of the surge tanks becomes full, it is presumed that the liquid refrigerant in another surge tank is low, and the switching valve is switched to transfer the liquid refrigerant from the surge tank with a large amount of liquid refrigerant to the use side heat exchanger. By pumping,
The liquid refrigerant in the surge tank can be continuously and reliably pumped to the use side heat exchanger. Therefore, the cooling operation using the cold heat of the ice in the ice heat storage tank can be performed.

Further, an on-off valve and a small heat exchanger are sequentially provided at an oil outlet of an oil separation tank provided on the suction side of the small compressor, and the refrigerant liquid flowing into the oil separation tank is temporarily stored, so that the refrigerant liquid is temporarily stored. After evaporating the oil to make the refrigerant liquid rich in oil, the on-off valve is opened, and the refrigerant liquid rich in oil flows out. By passing the refrigerant liquid through a small heat exchanger, the liquid component of the refrigerant is further evaporated, and the oil is returned to the small compressor.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of an air conditioner 10 including an ice heat storage tank 6 according to the present invention.

The air conditioner 10 shown in FIG. 1 includes a heat source side unit 5, an ice heat storage unit 8, and a use side unit 1.
It consists of two. The heat source side unit 5 is an ice heat storage unit 8
Is connected to the use side unit 12 by a refrigerant pipe.

The heat source side unit 5 includes a compressor 1, a four-way valve 3, a heat source side heat exchanger 2, and an electric expansion valve 4 in order of the refrigerant pipe 1.
3 is connected. In addition, the user side unit 12
Is connected to the refrigerant pipe 14 by the use side heat exchanger 9 and the electric expansion valve 15.
The opening degree of the electric expansion valve 15 is adjusted according to the air conditioning load.

The ice heat storage unit 8 includes an ice heat storage tank 6 having a built-in refrigerant pipe 7 for making ice.
A second on-off valve 19 is disposed on the on-off valve 17 and the refrigerant pipe 18, respectively. Further, one end of the refrigerant pipe 7 is connected via the refrigerant pipe 20 to the use side unit 12 side of the mounting position of the first opening / closing valve 17, and the electric expansion valve 21 is disposed on the refrigerant pipe 20. The other end of the refrigerant pipe 7 includes a third on-off valve 22 and is connected to the use side unit 12 via the refrigerant pipe 23.

The ice heat storage tank 6 is filled with brine such as water, and an ice making refrigerant pipe 7 is disposed in the ice heat storage tank 6 in a submerged state. During the ice heat storage operation, the liquid refrigerant flows from the heat source side heat exchanger 2 into the refrigerant pipe 7 in the ice heat storage tank 6 and evaporates. Is formed.

The refrigerant pipe 20 includes an electric expansion valve 21 and a refrigerant pipe 7.
Between the two surge tanks 25 via the refrigerant pipe 24.
A and 25B are connected in parallel. These surge tanks 25 </ b> A and 25 </ b> B are connected via the refrigerant pipe 26 to the use side unit 12 side of the first on-off valve 17 attached to the refrigerant pipe 16. Thereby, the surge tanks 25A and 25B
Is disposed between the refrigerant pipe 7 in the ice heat storage tank 6 and the use side heat exchanger 9 so that the liquid refrigerant condensed by the cold stored in the ice in the ice heat storage tank 6 is stored. become.

The refrigerant pipe 24 has surge tanks 25A, 2
Inflow side check valves 27A and 27B are provided on the inflow side of 5B,
The refrigerant pipe 26 is provided with outflow-side check valves 28A and 28B on the outflow side of the surge tanks 25A and 25B, respectively.
These inflow-side check valves 27A and 27B allow the flow of the refrigerant flowing from the refrigerant pipe 7 in the ice heat storage tank 6 toward the surge tanks 25A and 25B, and the outflow-side check valves 28A and 28B.
From the surge tanks 25A and 25B to the use side heat exchanger 9
Allow the flow of the refrigerant flowing in the lateral direction.

The surge tanks 25A and 25B are connected to refrigerant valves 29, 30, 31, 32, 33 via switching valves 34,
It is connected to an oil separation tank 35 and a small compressor 36.
One end of each of the refrigerant pipes 29, 30, 31, and 32 is connected to each port of the switching valve 34, and the other end of the refrigerant pipe 29 passes through the auxiliary heat exchanger 37 to the discharge port of the small compressor 36. Connected. The other end of the refrigerant pipe 32 is connected to an inlet of an oil separation tank 35 described later. The other ends of the refrigerant pipes 30 and 31 are connected to surge tanks 25A and 25B, respectively. The refrigerant pipe 33 is connected to a refrigerant outlet of the oil separation tank 35, and the other end is connected to a suction port of the small compressor 36. An on-off valve 38 and an auxiliary heat exchanger 37 are sequentially provided at the oil outlet of the oil separation tank 35, and are connected to the refrigerant pipe 33. The on-off valve 38 is normally closed, and is opened once every time the switching valve 34 is switched a plurality of times. In the auxiliary heat exchanger 37, the refrigerant liquid containing a large amount of oil separated from the oil separation tank 35 exchanges heat with the high-temperature and high-pressure refrigerant discharged from the small compressor 36 to evaporate the liquid component of the refrigerant.

By the switching operation of the switching valve 34, the communication between the refrigerant pipe 29 and the refrigerant pipe 30 and the communication between the refrigerant pipe 31 and the refrigerant pipe 32 (A side flow path), the refrigerant pipe 29 and the refrigerant pipe 31 are performed.
And the communication between the refrigerant pipes 30 and 32 (the B-side flow path) are selectively switched. In addition, small compressor 3
Reference numeral 6 denotes a compressor having a smaller capacity (capacity of 1/10 to 1/20) than the compressor 1 in the heat source side unit 5 and is operated only during the cooling / cooling operation of the air conditioner 10. The refrigerant discharged from the small compressor 36 has the same composition as the refrigerant discharged from the compressor 1 of the heat source side unit 5.

By operating the switching valve 34, the small compressor 36
High-pressure gas refrigerant from the surge tank 25A or 25B
The liquid refrigerant that has been pressure-fed inside and stored therein is pressure-fed to the use-side heat exchanger 9.

A sensor 39 and an oil separation tank 35 are provided at the suction port of the small compressor 36. The oil separation tank 35 has a built-in sensor 39 and a surge tank 25.
When the inside of the surge tank 25A or 25B is filled with the refrigerant liquid, the refrigerant liquid flows into the oil separation tank 35 and is detected. Can be detected.

The control device 40 takes in the information detected by the sensor 39 of the oil separation tank 35 and
The switching valve 34 is switched when either one of 5A and 25B is filled with the refrigerant liquid. When the switching valve 34 is set to the A-side flow path, the high-pressure gas refrigerant from the small compressor 36 flows into the surge tank 25A, and the surge tank 2 stored in the surge tank 25A.
Depress the 5A liquid level. The liquid refrigerant stored in the surge tank 25A is pressure-fed to the use side heat exchanger 9, where it evaporates and is cooled. The refrigerant gas evaporated in the use side heat exchanger 9 is condensed in the refrigerant pipe 7 of the ice heat storage tank 6 and stored in the surge tank 25B as a liquid refrigerant. Since the refrigerant gas is sucked into the small compressor 36 in the surge tank 25B, when the refrigerant liquid pools and the surge tank 25B becomes almost full, the refrigerant liquid flows out and flows into the oil separation tank 35. In the oil separation tank 35, the built-in sensor 39 uses the refrigerant liquid to operate the surge tank 25A or 25B.
Is detected that one of the surge tanks 25 is full. In general, the sum of the refrigerant liquid amount of the surge tank 25A and the refrigerant liquid amount of the surge tank 25B hardly changes. Therefore, when one of the surge tanks 25 becomes full, the refrigerant changes to a state in which the other surge tank 25 hardly exists. Adjustment of the liquid volume is performed. When the sensor 39 of the oil separation tank 35 detects the refrigerant liquid, the control device 40 switches the refrigerant flowing to the surge tank 25 by the switching valve 34. Thereby, the flow of the refrigerant gas from the small compressor 36 is switched and the surge tank 25 (the surge tank 25
A or 25B), the liquid refrigerant is supplied to the use side heat exchanger 9.

Next, the operation of returning the oil to the small compressor 36 will be described.

In the surge tank 25, a refrigerant liquid in which oil is dissolved is accumulated. The oil and the refrigerant have different solubilities, and the oil has a property of being separated from the refrigerant in the surge tank 25 at a low temperature. The lower the temperature is, the larger the ratio of this separation is. Since the specific gravity of the oil is smaller than that of the refrigerant, the oil liquid tends to collect near the liquid level in the tank. When the small compressor 36 operates, the liquid level in the surge tank 25 connected to the suction side of the small compressor 36 rises. When the liquid level becomes full, the refrigerant liquid passes through the switching valve 34 and the oil separation tank 35
Flows into. When a certain amount flows into the oil separation tank 35, the sensor 39 detects that the surge tank 25 is full, and the switching valve 34 is switched. When the operation is continued and the full liquid is detected, the refrigerant liquid flows into the oil separation tank 35 each time the liquid is detected. The refrigerant liquid flowing into the oil separation tank 35 is accumulated, is gradually vaporized, and is discharged from the refrigerant pipe 33. The liquid in the oil separation tank 35 gradually becomes a refrigerant liquid having a high oil content. After the switching of the switching valve 34 is repeated a plurality of times, the on-off valve 38 is opened. The on-off valve 38 is opened every other time, or when the oil return amount is small, once every few times. The oily refrigerant flowing out of the on-off valve 38 is supplied to the auxiliary heat exchanger 37 by the small compressor 3.
The refrigerant exchanges heat with the high-temperature and high-pressure refrigerant gas discharged from 6 to evaporate the refrigerant. Thus, the oil and the refrigerant gas are returned from the suction port of the small compressor 36.

Next, the ice heat storage operation, the cooling / cooling operation, and the normal cooling operation of the air conditioner 10 will be described.

[A] Ice Thermal Storage Operation The ice thermal storage operation of the air conditioner 10 is performed by, for example, transferring the liquid refrigerant from the heat source side heat exchanger 2 to the ice during a low electricity rate period from 10:00 at night to 8:00 in the next morning. In this operation, ice is supplied into the refrigerant pipe 7 of the heat storage tank 6 and ice is formed in the ice heat storage tank 6.

In this case, the electric expansion valve 15 is closed, and the first on-off valve 17, the second on-off valve 19, the third on-off valve 22
And the electric expansion valve 21 is opened.

In this state, the compressor 1 of the heat source side unit 5
Is operated, the gas refrigerant discharged from the compressor 1 is condensed in the heat source side heat exchanger 2, decompressed through the electric expansion valves 4 and 21, and enters the refrigerant pipe 7 of the ice heat storage tank 6. Inflow. The refrigerant flowing into the refrigerant pipe 7 evaporates, and forms ice on the outer periphery of the refrigerant pipe 7. After that, the gas refrigerant in the refrigerant pipe 7 of the ice heat storage tank 6 passes through the refrigerant pipes 23 and 18 to the four-way valve 3.
And returned to the compressor 1.

[B] Cooling / cooling operation In the cooling / cooling operation of the air conditioner 10, for example, during the daytime when the temperature rises, the air is liquefied by the cold heat of the ice in the refrigerant pipe 7 of the ice heat storage tank 6. The operation is performed such that the liquid refrigerant stored in the surge tanks 25A and 25B is supplied to the use-side heat exchanger 9.

In this case, the first on-off valve 17, the second on-off valve 19 and the electric expansion valve 21 are closed, and the electric expansion valve 15
And the third on-off valve 22 is opened. The compressor 1 of the heat source side unit 5 is in a stopped state.

In this state, the small compressor 36 is operated,
The control device 40 alternately switches the switching valve 34 between the A-side flow path and the B-side flow path based on the liquid detection signal of the sensor 39 of the oil separation tank 35. For example, the oil separation tank 35
When the sensor 39 detects the refrigerant liquid, the control device 40
Sets the switching valve 34 from the B-side flow path to the A-side flow path to guide the high-pressure gas refrigerant discharged from the small compressor 36 into the surge tank 25A. Thereby, this surge tank 25A
The stored liquid refrigerant therein is supplied to the use side heat exchanger 9 via the outflow side check valve 28A and the refrigerant pipe 16. Surge tank 25
The liquid refrigerant stored in A passes through the refrigerant pipe 7 of the ice heat storage tank 6 and is a liquid refrigerant condensed by the cold stored in the ice in the ice heat storage tank 6. By evaporating in the room, the room can be cooled by the heat radiation (cooling) of the cold heat of ice and the latent heat of evaporation of the refrigerant.

The gas refrigerant evaporated in the use side heat exchanger 9 flows into the refrigerant pipe 7 of the ice heat storage tank 6 through the third on-off valve 22 and the refrigerant pipe 23, and as described above, the inside of the ice heat storage tank 6 Condensed by the ice and becomes a liquid refrigerant, and flows into the surge tank 25B via the inflow-side check valve 27B.

At this time, since the pressure in the surge tank 25A is high, the liquid refrigerant in the refrigerant pipe 7 of the ice heat storage tank 6 flows into the surge tank 25B without flowing into the surge tank 25A. Similarly, since the pressure in the surge tank 25B is lower than that in the surge tank 25A, the refrigerant stored in the surge tank 25B does not flow out to the use side heat exchanger 9 through the outflow check valve 28B.

Next, when the sensor 39 of the oil separation tank 35 detects the refrigerant liquid, the control device 40 uses the switching valve 34 as the B-side flow path to convert the high-pressure gas refrigerant discharged from the small compressor 36 into the refrigerant. It is guided into the surge tank 25B via the pipe 29 and the refrigerant pipe 31. Then, the liquid refrigerant stored in the surge tank 25B flows into the use-side heat exchanger 9 via the outflow-side check valve 28B, the refrigerant pipe 26, and the electric expansion valve 15 and evaporates. And the room is cooled by the latent heat of evaporation. The gas refrigerant from the use side heat exchanger 9 passes through the refrigerant pipe 14 and the third on-off valve 22 and is condensed by the cold heat of the ice in the refrigerant pipe 7 of the ice heat storage tank 6 to become a liquid refrigerant.
And it flows into the surge tank 25A through the inflow side check valve 27A.

The control device 40 switches the switching valve 34 when the sensor 39 of the oil separation tank 35 detects the refrigerant liquid, for example, sets the A side flow path, and then the sensor 39 of the oil separation tank 35 detects the refrigerant liquid. Upon detection, the switching valve 34 is set to the B-side flow path. First, the operation is performed from the position of the switching valve 34 at the time of stopping the operation, and the switching valve 34 is switched when the sensor 39 of the oil separation tank 35 detects the refrigerant liquid. The above operation is repeated to continue the cooling / cooling operation.

[C] Normal Cooling Operation The normal cooling operation of the air conditioner 10 is a cooling operation performed without using the cold heat stored in the ice in the ice heat storage tank 6, and includes the electric expansion valve 21 and the third opening / closing operation. The valve 22 is closed, and the first on-off valve 17, the second on-off valve 19, and the electric expansion valves 4 and 15 are opened.

In this state, when the compressor 1 is operated, the gas refrigerant discharged from the compressor 1 is condensed in the heat source side heat exchanger 2, and the electric expansion valve 4, the refrigerant pipes 13, 16 and After flowing into the use side heat exchanger 9 through the electric expansion valve 15, evaporating in the use side heat exchanger 9, and cooling the room by the latent heat of evaporation, the compressor 1 passes through the refrigerant pipe 18 and the four-way valve 3. Returned to

Although the present invention has been described based on one embodiment, the present invention is not limited to this. The on-off valve disposed at the oil outlet of the oil separation tank 35 is opened after the switching of the switching valve 34 is repeated a plurality of times, but the amount of the refrigerant liquid stored in the oil separation tank 35 is detected. Alternatively, the on-off valve may be opened.

[0042]

As described above, the sensor is attached to the oil separation tank to detect the refrigerant liquid flowing out of the surge tanks A and B, so that either of the surge tanks A and B is filled with the liquid refrigerant. Can be determined. When the refrigerant liquid flows into the oil separation tank, it is determined that one of the surge tanks has been filled with the liquid refrigerant or that it has just been filled, and the liquid refrigerant is immediately transferred from the other surge tank to the use side heat exchanger. Pump. As a result, the liquid refrigerant in the surge tanks A and B can be continuously and reliably pumped to the use side heat exchanger without stagnation, so that the cooling / cooling operation using the cold heat of the ice in the ice storage tank can be performed. Legal cooling / cooling operation can be performed favorably without the possibility of cavitation of a refrigerant liquid circulation pump such as this type of conventional air conditioner.

Also, by providing an oil separation tank on the suction side of the small compressor, oil overflowing from the small compressor is separated from the refrigerant liquid in the surge tank and returned to the small compressor. The mechanism has been configured to prevent poor lubrication, abnormal wear and seizure of small compressors even when suctioning refrigerant gas from another surge tank while supplying high-pressure gas refrigerant into one surge tank. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of an air conditioner including an ice heat storage tank according to the present invention.

FIG. 2 is a configuration diagram illustrating a conventional air conditioner including an ice heat storage tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Heat source side heat exchanger 5 Heat source side unit 6 Ice heat storage tank 8 Ice heat storage unit 9 User side heat exchanger 10 Air conditioner 25A, 25B Surge tank 34 Switching valve 35 Oil separation tank 36 Small compressor 37 Auxiliary heat Exchanger 38 On-off valve 39 Sensor 40 Control device

Claims (2)

[Claims] 1. A heat source side unit including a compressor and a heat source side heat exchanger, a device for generating and storing ice in an ice heat storage tank, a plurality of surge tanks for storing liquid refrigerant, a small compressor, and the like. In an air conditioner that performs ice heat storage operation and cooling operation by combining an ice heat storage unit with a use side unit having a use side heat exchanger, it has a smaller capacity than the compressor of the heat source side unit. A compressor, a switching valve, a surge tank, a use-side heat exchanger, and a device that generates and stores ice are connected by a refrigerant pipe to form a refrigeration cycle using ice heat storage, and oil is separated into the suction side of a small compressor. A sensor is provided in the tank and the oil separation tank, and the surge tank, which has a large amount of liquid refrigerant, is discharged to the small compressor in accordance with the state of the liquid in the surge tank connected to the suction side of the small compressor. The switching valve switches the refrigerant flowing through the surge tank so that the surge tank is on the suction side of the small compressor, and the switch valve provided at the oil outlet of the oil separation tank once every time this switching valve switches multiple times. An air conditioner provided with an ice heat storage tank, which is opened to allow oil to flow out. 2. A small heat exchanger is disposed between an on-off valve of an oil separation tank and a suction port of a small compressor, and the auxiliary heat exchanger separates refrigerant discharged from the small compressor from the oil separation tank. The air conditioner provided with the ice heat storage tank according to claim 1, wherein heat exchange is performed with a refrigerant containing a large amount of oil.