JPWO2016056078A1 - Air conditioner - Google Patents

Abstract

A first heating mode in which the refrigerant discharged from the compressor 1 flows into the use side heat exchanger 6 to perform a heating operation, and the refrigerant discharged from the compressor 1 is used on the use side heat exchanger 6 and the heat source side heat exchanger. And a second heating mode in which the heating operation and the defrosting operation are performed simultaneously, and a refrigerant corresponding to the volume of the heat storage heat exchanger 25 in the second heating mode. The opening of the first expansion device 5 during the second heating mode is smaller than the opening of the first expansion device 5 during the first heating mode so that the amount can be stored in the use-side heat exchanger 6. Are controlled by

Description

  The present invention relates to an air conditioner that includes a heat storage tank and can perform heating operation and defrosting operation simultaneously.

  In an air-cooled air conditioner, when the outdoor temperature is low and the humidity is high, frost adheres to the heat source side heat exchanger (outdoor unit) during heating operation, so it is necessary to perform defrosting operation periodically. In the conventional defrosting operation, the four-way valve is switched so that the flow path of the refrigerant discharged from the compressor that flows to the use side heat exchanger (indoor unit) side during the heating operation flows to the heat source side heat exchanger side. Therefore, heating operation and defrosting operation could not be performed at the same time.

Then, the air conditioner which enabled it to perform heating operation and defrosting operation simultaneously is proposed (for example, refer patent document 1).
In Patent Document 1, the refrigerant discharged from the compressor is distributed to the use side heat exchanger side and the heat source side heat exchanger side, and the indoor air is heated and heated in the use side heat exchanger, and at the same time, the heat source Defrosting is performed by melting frost adhering to the outer surface of the side heat exchanger. Then, the liquid refrigerant condensed in the use side heat exchanger and the liquid refrigerant condensed in the heat source side heat exchanger are merged on the way, and then evaporated by the heat storage material that accumulates the heat in the heat storage tank to form a gas It becomes a refrigerant and is sucked into the compressor again.

Japanese Patent No. 4367237 (see, for example, [0061] to [0067], FIG. 1 and FIG. 2)

  In an air conditioner equipped with a heat storage tank as in Patent Document 1, it is necessary to additionally fill the amount of refrigerant for the heat exchanger in the heat storage tank, but in an operation using the heat exchanger in the heat storage tank as an evaporator. In addition, there is a problem that the refrigerant for the additional charge becomes surplus refrigerant and liquids back to the compressor.

  The present invention has been made in order to solve the above-described problems. In an air conditioner that includes a heat storage tank and can perform heating operation and defrosting operation simultaneously, a liquid back to the compressor is provided. The purpose is to suppress.

  In the air conditioner according to the present invention, a compressor, a first flow path switching device, a heat source side heat exchanger, a first switching valve, a first expansion device, a use side heat exchanger, and a second flow path switching device are sequentially piped. Connected to the pipe branching from the pipe connecting the compressor and the first flow path switching device and connected to the pipe connecting the heat source side heat exchanger and the first switching valve. The pipe is provided with a second switching valve, branched from the pipe connecting the first switching valve and the first throttle device, and connected to join the second flow path switching device The piping is provided with a second expansion device, and a heat storage tank provided with a heat storage material and a heat storage heat exchanger in series, and the heat storage tank is closer to the second flow path switching device than the second expansion device. The first flow path switching device, the second flow path switching device, the first throttling device, the front A first throttle device, a first switching valve, and a control device for controlling the second switching valve, wherein the refrigerant discharged from the compressor flows into the use side heat exchanger to perform a heating operation. And at least a heating mode and a second heating mode in which the refrigerant discharged from the compressor is caused to flow into the use side heat exchanger and the heat source side heat exchanger to simultaneously perform the heating operation and the defrosting operation. An air conditioner, wherein the refrigerant amount corresponding to the volume of the heat storage heat exchanger can be stored in the use side heat exchanger during the second heating mode. The opening of the first expansion device is controlled to be smaller than the opening of the first expansion device during the first heating mode.

  According to the air conditioner of the present invention, by controlling the opening of the first expansion device during the second heating mode to be smaller than the opening of the first expansion device during the first heating mode, Since the amount of refrigerant corresponding to the volume of the heat storage heat exchanger can be stored in the use side heat exchanger by increasing the amount of refrigerant stored in the use side heat exchanger during the two heating mode, the compressor 1 Liquid back to the surface can be suppressed.

It is a refrigerant circuit figure of the air conditioner concerning an embodiment of the invention. It is a figure which shows the relationship between the subcool | coolant by the side of the exit of the utilization side heat exchanger in the air conditioner which concerns on embodiment of this invention, the opening degree of a 1st expansion device, and the refrigerant | coolant amount stored in a utilization side heat exchanger. . It is a control flow of the air conditioner which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings, the relationship of the size of each component may be different from the actual one.

Embodiment.
(Configuration of refrigerant circuit of air conditioner)
FIG. 1 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention.
The refrigerant circuit of the air conditioner according to the present embodiment includes the compressor 1, the first four-way valve 2, the heat source side heat exchanger 3, the first switching valve 4, the first expansion devices 5a to 5c, and the use side heat exchange. The containers 6a to 6c, the second four-way valve 21, and the accumulator 7 are sequentially connected in series by piping. Further, the pipe branched from the pipe connecting the compressor 1 and the first four-way valve 2 and connected to the pipe connecting the heat source side heat exchanger 3 and the first switching valve 4 to the pipe connected to the pipe A second switching valve 8 is provided. Further, the second throttle device 23 and the heat storage are connected to the pipe branched from the pipe connecting the first switching valve 4 and the first throttle devices 5 a to 5 c and joined to the second four-way valve 21. A tank 22 is provided in series. The heat storage tank 22 is provided closer to the second four-way valve 21 than the second expansion device 23, and includes a heat storage material 24 and a heat storage heat exchanger 25.

(Compressor)
The compressor 1 sucks refrigerant and compresses the refrigerant to a high temperature and high pressure state. The compressor 1 is not particularly limited as long as it can compress the sucked refrigerant into a high pressure state. For example, various types such as reciprocating, rotary, scroll, or screw can be used.
(First four-way valve, second four-way valve)
The first four-way valve 2 and the second four-way valve 21 are flow path switching devices that have first to fourth ports and switch the direction of refrigerant flow.
Note that a two-way valve or a three-way valve may be used in combination as the flow path switching device instead of the four-way valve.
The first four-way valve 2 corresponds to the “first flow path switching device” of the present invention, and the second four-way valve 21 corresponds to the “second flow path switching device” of the present invention.

(Heat source side heat exchanger)
The heat source side heat exchanger 3 functions as an evaporator or a radiator (condenser), performs heat exchange between air supplied from a fan (not shown) and the refrigerant, and evaporates or condenses the refrigerant. Is.
The heat source side heat exchanger 3 is not particularly limited as long as it can exchange heat between the air supplied from the fan and the refrigerant, and can evaporate or liquefy the refrigerant. . For example, various types such as a cross fin tube type and a cross flow type can be used.

(Switching valve)
The 1st switching valve 4 and the 2nd switching valve 8 control the flow of a refrigerant | coolant according to an operation mode by performing opening / closing control alternatively from them.
(First diaphragm device, second diaphragm device)
The first expansion devices 5a to 5c and the second expansion device 23 have a function as a pressure reducing valve or an expansion valve, and expand the refrigerant by reducing the pressure. The first throttling devices 5a to 5c and the second throttling device 23 are configured by those whose opening degree can be variably controlled, for example, a precise flow rate control means using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, and the like. Good.
Hereinafter, the first diaphragm device 5a to 5c may be referred to as the first diaphragm device 5 as a general term.

(Use side heat exchanger)
The use-side heat exchangers 6a to 6c function as radiators (condensers) and evaporators, exchange heat between air supplied from a fan (not shown) and the refrigerant, and condense the liquid into liquefied or evaporated gas. It is to become.
The usage-side heat exchangers 6a to 6c are not particularly limited as long as they can exchange heat between the air supplied from the fan and the refrigerant and can evaporate or liquefy the refrigerant. is not. For example, various types such as a cross fin tube type and a cross flow type can be used.
Moreover, in this Embodiment, although it was set as the structure provided with three utilization side heat exchangers, it is not limited to it, At least 2 or more should just be provided, and you may increase / decrease according to load.
Hereinafter, the usage-side heat exchangers 6a to 6c may be collectively referred to as the usage-side heat exchanger 6.
(accumulator)
The accumulator 7 is disposed on the suction side of the compressor 1 and stores excess refrigerant. In addition, the accumulator 7 should just be a container which can store an excessive refrigerant | coolant.

(Accumulation tank)
In the heat storage tank 22, a heat storage heat exchanger 25 is accommodated inside the heat storage material 24, and heat exchange is performed between the heat stored in the heat storage material 24 and the refrigerant flowing through the heat storage heat exchanger 25. Is to do.
The heat storage material 24 can store heat, such as polyethylene glycol, threitol, paraffin, sodium acetate trihydrate, sodium sulfate decahydrate, and the like.
The heat storage heat exchanger 25 is a heat exchanger for exchanging heat between the heat storage material 24 filled in the heat storage tank 22 and the refrigerant. In the present embodiment, the heat storage heat exchanger 25 is used as an evaporator.

The air conditioner according to the present embodiment is provided with a control device 50 that performs overall control of the operation of the air conditioner and a storage device 51 that stores various types of information.
A high pressure sensor 201, first temperature sensors 202a to 202c, and a second temperature sensor 203 are also provided.
The high pressure sensor 201 is provided in a pipe connecting the compressor 1 and the first four-way valve 2, and the first temperature sensors 202a to 202c are the first expansion devices 5a to 5c and the use side heat exchanger 6a. To 6c, and the second temperature sensor 203 is provided in the heat source side heat exchanger 3.

(High pressure sensor)
The high pressure sensor 201 detects the pressure of the high pressure refrigerant discharged from the compressor 1. The pressure information detected by the high pressure sensor 201 is sent to the control device 50 that performs overall control of the operation of the air conditioner, and is used for control of each actuator constituting the air conditioner.
(Temperature sensor)
The 1st temperature sensors 202a-202c each detect the temperature of the refrigerant | coolant which flows through the provided piping. The second temperature sensor 203 detects the temperature of the heat source side heat exchanger 3. The temperature information detected by the first temperature sensors 202a to 202c and the second temperature sensor 203 is sent to the control device 50 that performs overall control of the operation of the air conditioner, and is used to control each actuator constituting the air conditioner. Will be used.

(Control device)
The control device 50 includes a drive frequency of the compressor 1, a rotation speed of the fan, switching of the first four-way valve 2 and the second four-way valve 21, opening degrees of the first throttle devices 5a to 5c and the second throttle device 23, The opening and closing of the first switching valve 4 and the second switching valve 8 are controlled. That is, the control device 50 is configured by a microcomputer or the like, and controls each actuator (driving component constituting the air conditioner) on the basis of detection information from various detection devices and instructions from the remote controller, and air conditioning. Run the machine.
The control device 50 calculates a saturation temperature (condensation temperature) from the pressure of the high-pressure refrigerant detected by the high-pressure sensor 201, and from the calculated saturation temperature and the temperature information detected by the first temperature sensors 202a to 202c, An arithmetic unit that calculates the subcooling on the outlet side (liquid side) of the use side heat exchangers 6a to 6c is provided.
(Storage device)
The storage device 51 is configured by a memory or the like and stores various information. In FIG. 1, the control device 50 is illustrated as a separate body, but is not limited thereto, and may be integrated with the control device 50 or a separate body.
The storage device 51 stores in advance information related to the amount of refrigerant corresponding to the volume of the heat storage heat exchanger 25 and the relationship between the pressure and saturation temperature for each refrigerant.

  The subcool (SC) can be calculated by the following equation.

[Formula 1]
Subcool on the outlet side of the use side heat exchanger 6a = saturation temperature−temperature detected by the first temperature sensor 202a

  The sub-cooling on the outlet side of the use side heat exchanger 6b and the use side heat exchanger 6c is calculated by setting the first temperature sensor 202a to the first temperature sensor 202b and the first temperature sensor 202c, respectively, in the above formula. be able to.

  The opening degree of the first expansion devices 5a to 5c is controlled so that the subcool on the outlet side of the use side heat exchanger 6a becomes a predetermined target value.

FIG. 2 shows the sub-cooling on the outlet side of the use side heat exchangers 6a to 6c and the opening degree of the first expansion devices 5a to 5c and the use side heat exchangers 6a to 6c in the air conditioner according to the embodiment of the present invention. It is a figure which shows the relationship with the refrigerant | coolant amount stored.
As shown in FIG. 2, the subcooling on the outlet side of the use side heat exchangers 6a to 6c increases as the opening degree of the first expansion devices 5a to 5c decreases, and the refrigerant stored in the use side heat exchangers 6a to 6c. The amount increases. That is, the subcool on the outlet side of the use side heat exchangers 6a to 6c and the refrigerant amount stored in the use side heat exchangers 6a to 6c are in a proportional relationship, and the subcool on the outlet side of the use side heat exchangers 6a to 6c. And the opening degree of the first expansion devices 5a to 5c are in an inversely proportional relationship. This characteristic is stored in the storage device 51 in advance.

The air conditioner according to the present embodiment includes a plurality of operation modes, and includes at least a first heating mode and a second heating mode.
(First heating mode)
In the first heating mode, the first four-way valve 2 is switched so that the discharge side of the compressor 1 communicates with the use side heat exchangers 6a to 6c, and the second four-way valve 21 is switched to connect the heat storage tank 22 and the closed circuit. It is in a state of communication. Further, the first switching valve 4 is opened, the second switching valve 8 is closed, the first throttle devices 5a to 5c are opened to a predetermined opening degree, and the second throttle device 23 is fully closed to form a flow path. Therefore, in the first heating mode, the refrigerant does not flow into the heat storage tank 22.

First, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is discharged and then flows into the use side heat exchangers 6 a to 6 c via the first four-way valve 2. The refrigerant flowing into the use-side heat exchangers 6a to 6c dissipates heat and is condensed to become a high-pressure two-phase refrigerant, and is expanded by the first expansion devices 5a to 5c to become a low-pressure two-phase refrigerant. The refrigerant that has flowed into the heat source side heat exchanger 3 via the first switching valve 4 absorbs heat and becomes evaporated gas refrigerant, and then is compressed via the first four-way valve 2 and the accumulator 7. Return to Machine 1.
That is, the first heating mode is a mode in which the refrigerant discharged from the compressor 1 is caused to flow into the use side heat exchanger 6 and the heating operation (only) is performed.

(Second heating mode)
In the second heating mode, the first four-way valve 2 is switched and the discharge side of the compressor 1 communicates with the heat source side heat exchanger 3, and the second four-way valve 21 is switched and the heat storage tank 22 and the accumulator 7 communicate with each other. It is in a state. Further, the first switching valve 4 is closed, the second switching valve 8 is opened, the first throttle devices 5a to 5c are opened to a predetermined opening degree, the second throttle device 23 is opened to a predetermined opening degree, and a flow path is formed. ing. Therefore, in the second heating mode, the refrigerant flows through the heat storage tank 22.

First, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is discharged and then divided into the first four-way valve 2 side and the second switching valve 8 side.
The refrigerant branched to the first four-way valve 2 side flows into the use side heat exchangers 6 a to 6 c via the first four-way valve 2. The refrigerant flowing into the use-side heat exchangers 6a to 6c dissipates heat and is condensed to become a high-pressure two-phase refrigerant, and is expanded by the first expansion devices 5a to 5c to become a low-pressure two-phase refrigerant. Thereafter, the heat flows into the heat storage heat exchanger 25 of the heat storage tank 22 via the second expansion device 23. The refrigerant that has flowed into the heat storage heat exchanger 25 absorbs heat from the heat storage material 24 to become evaporated gas refrigerant, and then flows toward the second four-way valve 21.

On the other hand, the refrigerant branched to the second switching valve 8 side is depressurized by the second switching valve 8 to become a low-temperature and high-pressure gas refrigerant and flows into the heat source side heat exchanger 3. The refrigerant flowing into the heat source side heat exchanger 3 dissipates heat there, melts and condenses frost adhering to the heat source side heat exchanger 3, passes through the first four-way valve 2, and then passes through the second four-way valve 21. It merges with the refrigerant passed through.
The merged refrigerant returns to the compressor 1 via the accumulator 7.
That is, the second heating mode is a mode in which the refrigerant discharged from the compressor 1 is caused to flow into the use side heat exchanger 6 and the heat source side heat exchanger 3 to simultaneously perform the heating operation and the defrosting operation.

(Air conditioner control flow)
FIG. 3 is a control flow of the air conditioner according to the embodiment of the present invention.
Hereinafter, the control flow of the air conditioner according to the present embodiment will be described with reference to FIG.
First, the operation is started in the first heating mode (S1), and the outlet side (liquid side) subcool (hereinafter referred to as SC1) of the use side heat exchanger 6 is set to a predetermined target subcool (hereinafter referred to as T_SC1). The opening degree of the first expansion devices 5a to 5c is controlled (S2). And SC1 of the use side heat exchangers 6a-6c after the control is each memorize | stored in the memory | storage device 51 (S3). SC1 is proportional to the opening degree of the first expansion devices 5a to 5c.

Next, the temperature of the heat source side heat exchanger 3 detected by the second temperature sensor 203 during the first heating mode is compared with a predetermined first temperature (S4).
Here, the first temperature is a temperature at which frost adheres to the outer surface of the heat source side heat exchanger 3 and defrosting is required.
When the temperature of the heat source side heat exchanger 3 is higher than the first temperature (No in S4), the process returns to S2. On the other hand, when the temperature of the heat source side heat exchanger 3 is equal to or lower than the first temperature (Yes in S4), a target subcool (hereinafter referred to as T_SC2) is calculated (S5).
Here, T_SC2 is obtained as follows.

First, the minimum value is selected from SC1 of the use side heat exchangers 6a to 6c stored in S2.
Then, from FIG. 2, the subcool difference ΔSC is obtained from the minimum value of the selected SC1 and the refrigerant amount corresponding to the volume of the heat storage heat exchanger 25 stored in advance, and is calculated by the following equation.

[Formula 2]
T_SC2 = SC1 + ΔSC
Note that T_SC2> SC1.

  As described above, T_SC2 can be obtained from SC1 and ΔSC. In other words, from the opening degree of the first expansion devices 5a to 5c in the first heating mode and the refrigerant amount corresponding to the volume of the heat storage heat exchanger 25, the first expansion devices 5a to 5c in the second heating mode. The target opening is obtained.

Then, after calculating T_SC2, the operation is shifted to the second heating mode (S6), and the subcooling on the outlet side (liquid side) of the use side heat exchanger 6 where SC1 is the minimum value (hereinafter referred to as SC2). However, the opening degree of the 1st expansion device 5 is controlled so that it may become T_SC2 (S7). Thereafter, the temperature of the heat source side heat exchanger 3 detected by the second temperature sensor 203 during the second heating mode is compared with a predetermined second temperature (S8).
Here, the second temperature is a temperature at which defrosting of the heat source side heat exchanger 3 becomes unnecessary.
When the temperature of the heat source side heat exchanger 3 is lower than the second temperature (No in S8), the process returns to S7. On the other hand, when the temperature of the heat source side heat exchanger 3 is equal to or higher than the second temperature (Yes in S8), the process returns to S1 to shift to the first heating mode and start operation.

  Note that the minimum value of SC1 is selected and the opening degree of the first expansion device 5 of the use side heat exchanger 6 where SC1 is the minimum value is controlled by the use side heat with the least amount of stored refrigerant. This is because the exchanger 6 is selected and controlled. That is, when the volumes of the usage-side heat exchangers 6a to 6c are the same, the usage-side heat exchanger 6 having the largest margin in the amount of refrigerant that can be stored is selected and controlled, so that the heat for heat storage. This is to avoid a situation in which the refrigerant amount corresponding to the volume of the exchanger 25 cannot be stored.

SC1 corresponds to the “first subcool” of the present invention, and SC2 corresponds to the “second subcool” of the present invention.
T_SC1 corresponds to the “first target subcool” of the present invention, and T_SC2 corresponds to the “second target subcool” of the present invention.

  As mentioned above, according to the air conditioner concerning this Embodiment provided with the thermal storage tank 22, the opening degree of 1st expansion device 5a-5c is controlled so that it may become T_SC1 during 1st heating mode, and utilization. The SC1 on the outlet side (liquid side) of the side heat exchangers 6a to 6c is stored in the storage device 51, respectively. Then, the use side heat exchanger 6 having the minimum value in SC1 is selected, and T_SC2 is calculated from the minimum value of SC1 and the refrigerant amount corresponding to the volume of the heat storage heat exchanger 25. Thereafter, the opening degree of the first expansion device 5 is controlled so that SC2 on the outlet side (liquid side) of the selected use side heat exchanger 6 becomes T_SC2. By doing so, in the second heating mode in which the heat storage heat exchanger 25 in the heat storage tank 22 is used as an evaporator, the amount of refrigerant corresponding to the volume of the heat storage heat exchanger 25 is selected as the use side heat exchanger 6. Therefore, liquid back to the compressor 1 can be suppressed.

  That is, by controlling the opening of the first expansion device 5 during the second heating mode to be smaller than the opening of the first expansion device 5 during the first heating mode, By increasing the amount of refrigerant stored in the exchanger 6, the amount of refrigerant corresponding to the volume of the heat storage heat exchanger 25 can be stored in the use-side heat exchanger 6, so that the liquid back to the compressor 1 can be reduced. Can be suppressed.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 1st four-way valve, 3 Heat source side heat exchanger, 4 1st switching valve, 5 1st expansion device, 5a 1st expansion device, 5b 1st expansion device, 5c 1st expansion device, 6 utilization Side heat exchanger, 6a Utilization side heat exchanger, 6b Utilization side heat exchanger, 6c Utilization side heat exchanger, 7 Accumulator, 8 Second switching valve, 21 Second four-way valve, 22 Heat storage tank, 23 Second throttle Device, 24 heat storage material, 25 heat storage heat exchanger, 50 control device, 51 storage device, 201 high pressure sensor, 202a first temperature sensor, 202b first temperature sensor, 202c first temperature sensor, 203 second temperature sensor.

In the air conditioner according to the present invention, a compressor, a first flow path switching device, a heat source side heat exchanger, a first switching valve, a first expansion device, and a use side heat exchanger are sequentially connected by piping, and the compression Branching from the pipe connecting the machine and the first flow path switching device, the second switching to the pipe connected to join the pipe connecting the heat source side heat exchanger and the first switching valve A valve is provided, branches from a pipe connecting the first switching valve and the first throttle device, and selectively passes to a suction side or a closed circuit of the compressor via a second flow path switching device. The pipe connected is provided with a second expansion device and a heat storage tank provided with a heat storage material and a heat exchanger for heat storage in series, and the heat storage tank is switched to the second flow path from the second expansion device. Provided on the apparatus side, the first flow path switching device, the second flow path switching device, the first throttle Apparatus, the second throttle device, the first switching valve, and a control device for controlling the second switching valve, and the refrigerant discharged from the compressor is allowed to flow into the use side heat exchanger for heating operation. A first heating mode to be performed, and a second heating mode in which the refrigerant discharged from the compressor is caused to flow into the use side heat exchanger and the heat source side heat exchanger to simultaneously perform the heating operation and the defrosting operation. and at least includes an air conditioner, the control device, the second by the refrigerant quantity corresponding to the volume of the heat storage heat exchanger during the heating mode is stored in the utilization-side heat exchanger urchin, the first and controls two opening degree of the first throttle device in the heating mode to be smaller than the opening degree of the first throttle apparatus in the first heating mode.

Claims (7)

The compressor, the first flow path switching device, the heat source side heat exchanger, the first switching valve, the first expansion device, the use side heat exchanger, and the second flow path switching device are sequentially connected by piping,
A pipe branched from a pipe connecting the compressor and the first flow path switching device, and connected to a pipe connecting the heat source side heat exchanger and the first switching valve, Two switching valves are provided,
The second throttle device, the heat storage material, and the heat storage are connected to the pipe branched from the pipe connecting the first switching valve and the first throttle device and joined to the second flow path switching device. A heat storage tank with a heat exchanger for use is provided in series,
The heat storage tank is provided on the second flow path switching device side from the second expansion device,
A controller for controlling the first flow path switching device, the second flow path switching device, the first throttle device, the second throttle device, the first switching valve, and the second switching valve;
A first heating mode in which the refrigerant discharged from the compressor flows into the use side heat exchanger to perform a heating operation; and the refrigerant discharged from the compressor exchanges heat with the use side heat exchanger A second heating mode in which the heating operation and the defrosting operation are performed at the same time by flowing into the air conditioner,
During the second heating mode, the first expansion device is opened during the second heating mode so that an amount of refrigerant corresponding to the volume of the heat storage heat exchanger can be stored in the use side heat exchanger. The air conditioner is controlled so that the degree is smaller than the opening of the first expansion device during the first heating mode. A plurality of the first expansion device and the use side heat exchanger are connected in parallel,
A storage device for storing various information;
During the first heating mode,
After controlling the opening degree of the plurality of first expansion devices so that the first subcools of the plurality of usage-side heat exchangers are predetermined first target subcools, A second target subcool that is larger than the first target subcool is calculated from the minimum value of the first subcool in the use side heat exchanger and the refrigerant amount corresponding to the volume of the heat storage heat exchanger. The air conditioner according to claim 1. During the second heating mode,
The opening degree of the first expansion device is controlled so that a subcool in the use side heat exchanger having the minimum value of the first subcool becomes the second target subcool. Air conditioner. 4. The air conditioner according to claim 2, wherein the use-side heat exchanger that stores a refrigerant amount corresponding to the volume of the heat storage heat exchanger has a minimum value of the first subcool. 5. After the operation is started in the first heating mode, when the temperature of the heat source side heat exchanger becomes equal to or lower than a predetermined first temperature, the mode is shifted to the second heating mode. The air conditioner as described in any one of Claims. The air conditioner according to claim 5, wherein when the temperature of the heat source side heat exchanger becomes equal to or higher than a predetermined second temperature, the first heating mode is entered. The air conditioner according to any one of claims 1 to 6, wherein the plurality of use side heat exchangers have the same volume.

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