JP2022024289A - Air conditioner - Google Patents

Abstract

To solve a problem of a conventional air conditioner performing refrigerant recovery operation at stopping or at refrigerant leakage that sufficient safety and reliability of the refrigerant recovery operation cannot be attained.SOLUTION: An air conditioner includes first refrigerant shut-off means, second refrigerant shut-off means, state detecting means for acquiring information for estimating a state of a refrigerant in an indoor unit, refrigerant storage means disposed between an expansion valve and the first refrigerant shut-off means, and control means for controlling operation of the device. After the refrigerant is recovered in an outdoor unit and the second refrigerant shut-off means is closed, the expansion valve is closed, and after the first refrigerant shut-off means is opened, the first refrigerant shut-off means is closed again.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for preventing leakage of a working refrigerant in an air conditioner that performs air conditioning using a refrigeration and heat pump cycle.

In recent years, in addition to the movement to emphasize the operating efficiency of air conditioners from the viewpoint of preventing global warming, the movement to regulate the use of refrigerants with a large global warming coefficient has been accelerated.

As a refrigerant with a small warming coefficient, carbon dioxide, which originally exists in nature, and hydrocarbons such as propane and butane, which are artificially synthesized, have a double bond in the molecular structure and have a double bond in the atmosphere. Hydrofluoroolefins (HFOs), which decompose in a short time, are attracting attention. As HFOs, 2,3,3,3-tetrafluoro-1-propene (R1234yf), 1,3,3,3-tetrafluoro-1-propene (R1234ze), etc. are attracting attention and some of them. Practical use has begun.

However, carbon dioxide has a high operating pressure and is difficult to use as an air conditioner in terms of operating efficiency, and it cannot be said that carbon dioxide has excellent characteristics as a refrigerant.

Further, since R1234yf and R1234ze have a high boiling point and a large pressure loss, there is a difficulty in operating efficiency when used in an air conditioner such as a room air conditioner. There is also a problem in that it has a slight flammability.

On the other hand, hydrocarbons, especially propane, have excellent characteristics as a refrigerant for air conditioners, but because they have high flame properties, if a refrigerant leaks, there is a risk of fire or explosion. It could not be used easily.

One of them is a technology for collecting flammable refrigerant in an outdoor unit to prevent the refrigerant from leaking into the room. Regarding the prevention of refrigerant leakage, not only combustible refrigerants but also chlorofluorocarbons currently in use are very important issues in terms of environmental impact, and refrigerant leakage in air conditioners is avoided regardless of whether they are flammable or non-flammable. There must be.

In the separate type air conditioner described in Patent Document 1, the refrigerant composed of combustible gas stored in the refrigerant circuit in the outdoor unit is prevented from leaking to the refrigerant circuit of the indoor unit while the air conditioner is stopped. For the purpose of disposing an actuator with a built-in valve that operates at a differential pressure on the refrigerant inlet side and outlet side of the indoor unit, respectively, an on-off valve is interposed in the pressure guiding tube that guides the discharge gas of the compressor to each actuator. ing.

According to the stop command, the on-off valve of the pressure guiding tube connected to the actuator on the refrigerant inlet side of the indoor unit is closed to perform the refrigerant recovery operation, and the refrigerant in the refrigerant circuit of the indoor unit is stored in the refrigerant circuit of the outdoor unit and then indoors. The on-off valve of the pressure guiding tube connected to the actuator on the refrigerant outlet side of the machine is closed to stop the compressor.

FIG. 2 shows a first embodiment of the air exchanger described in Patent Document 1, in which an indoor unit 14 attached to a chamber 11 and an outdoor unit 10 are connected to form a refrigerant circuit, and the outdoor unit is formed. In No. 10, the refrigerant is compressed by the compressor 1 to become a high-temperature and high-pressure gas refrigerant, dissipates and condenses in the outdoor heat exchanger 2 to become a high-pressure liquid refrigerant, and is decompressed by the throttle 3 to become a gas-liquid two-phase refrigerant in the room. The indoor heat exchanger 4 of the machine 14 absorbs heat and evaporates, and returns to the compressor 1 again.

An actuator 21 is provided on the inlet side of the indoor unit 14, and an actuator 22 is provided on the outlet side. The actuator 21 is provided with a pressure guiding tube 12 via a solenoid valve 15, and the actuator 22 is provided with a pressure guiding tube 13 via a solenoid valve 16. By supplying the discharged refrigerant of the compressor 1, the actuator 21 and the actuator 22 are opened.

When the solenoid valve 15 or the solenoid valve 16 is closed by the command of the controller 19, the supply of the discharged refrigerant of the compressor 1 is stopped, the actuator 21 or the actuator 22 is closed, and the refrigerant flows in the refrigerant circuit of the indoor unit 14. It has no structure.

Then, during the air conditioning operation, the controller 19 opens the solenoid valve 15 and the solenoid valve 16, so that the actuator 21 and the actuator 22 are opened and the chamber 11 can be air-conditioned.

When stopping the air conditioning, the controller 19 first closes the solenoid valve 15 and closes the actuator 21 to start the pump-down operation. When the refrigerant recovery progresses and the suction side pressure of the compressor 1 drops, the pressure sensor 7 operates, and in response to this, the controller 19 closes the solenoid valve 16, closes the actuator 21, and stops the compressor 1. The refrigerant recovery operation is terminated.

Further, a gas leak detection sensor 8 is provided in the chamber 11, and when a gas leak detection signal is input to the controller 19 during the air conditioning operation, the controller 19 outputs a stop command to perform the refrigerant recovery operation. At the same time as the compressor 1 is stopped, a gas leak alarm is output.

In Patent Document 2, in order to reduce the cost of the device in performing the same refrigerant recovery, the indoor unit liquid side (cooling inlet side) and gas side (cooling outlet side) are shut off, and the liquid side is an electromagnetic expansion valve and gas. The side is a shut-off valve. As for the refrigerant recovery operation method, after shutting off the electromagnetic expansion valve, the compressor is operated for a predetermined time, the compressor is stopped, and the shutoff valve is shut off.

Japanese Unexamined Patent Publication No. 8-166171 Japanese Unexamined Patent Publication No. 2000-97527

The conventional air conditioners of Patent Document 1 and Patent Document 2 use a flammable refrigerant, and when the operation is stopped or a refrigerant leak is detected in order to avoid danger of ignition or explosion in the room. , The refrigerant recovery operation is performed to remove the refrigerant from the refrigerant circuit on the indoor side.

In the case of Patent Document 1, the determination of the end of the refrigerant recovery is determined when a decrease in the refrigerant pressure on the suction side of the compressor is detected, and in the case of Patent Document 2, a predetermined time has elapsed from the start of the refrigerant recovery operation.

However, in such a refrigerant recovery end determination, depending on the operating conditions, there is a possibility that the flammable refrigerant in the refrigerant circuit on the indoor side cannot be sufficiently excluded, or the pressure of the refrigerant on the suction side of the compressor becomes a negative pressure and the refrigerant becomes negative. There is a possibility of introducing air into the circuit.

As a result, there is a risk that the residual refrigerant may leak and ignite, or the compressor may compress a flammable refrigerant or a mixture of refrigerating machine oil and air, resulting in an explosion of the outdoor unit.

Therefore, in order to solve these problems and prevent refrigerant leakage, the present invention appropriately performs the refrigerant recovery operation in the air conditioner that performs the refrigerant recovery operation at the end of the operation or at the time of the refrigerant leakage, in terms of safety and reliability. It provides an excellent device.

In order to solve the above-mentioned conventional problems, the air conditioner of the present invention has a compressor that compresses and sends out the working refrigerant, and outdoor heat that exchanges heat between the outdoor air sent by the outdoor blower and the working refrigerant. Refrigeration is performed by a exchanger, an outdoor unit having an expansion valve for decompressing and expanding the working refrigerant, and an indoor unit having an indoor heat exchanger that exchanges heat between the indoor air sent by the indoor blower and the working refrigerant. Alternatively, an air conditioner constituting the heat pump cycle, the first refrigerant blocking means for blocking the first refrigerant path connecting the outdoor unit and the indoor unit, and the second refrigerant connecting the outdoor unit and the indoor unit. A second refrigerant blocking means for blocking the path, a state detecting means for estimating the state of the operating refrigerant of the indoor unit, and a refrigerant storage means arranged between the expansion valve and the first refrigerant blocking means. A control means for controlling the operation of the device including the operation of the first refrigerant blocking means and the second refrigerant blocking means is provided, and the first refrigerant blocking means is closed when the operation is stopped to collect the operating refrigerant in the outdoor unit. After closing the second refrigerant shutoff means, the expansion valve is closed, then the first refrigerant shutoff means is opened, and then the first refrigerant shutoff means is closed again. ..

As a result, after the working refrigerant is recovered, a predetermined amount of working refrigerant stored in the refrigerant storage means can be discharged, and an appropriate amount of refrigerant can be left in the refrigerant circuit of the indoor unit to stop.

The air conditioner of the present invention may release a predetermined amount of the working refrigerant stored in the refrigerant storage means after recovering the working refrigerant, leaving an appropriate amount of the working refrigerant in the refrigerant circuit of the indoor unit and stopping. Therefore, even if the working refrigerant leaks on the indoor side, the amount of leakage is minimized, air is drawn into the refrigerant circuit to prevent the compressor from exploding, and the indoor unit and the outdoor unit are connected. It is possible to prevent the piping to be deformed by a slight external force, provide a safe and highly reliable air conditioner with a small environmental load.

Configuration diagram of the air conditioner harmonizer according to the first embodiment of the present invention Configuration diagram of a conventional air conditioner

The first invention comprises a compressor that compresses and sends out the working refrigerant, an outdoor heat exchanger that exchanges heat between the outdoor air sent by the outdoor blower and the working refrigerant, and expansion that decompresses and expands the working refrigerant. An air conditioner that constitutes a refrigeration or heat pump cycle with an outdoor unit having a valve and an indoor unit having an indoor heat exchanger that exchanges heat between the indoor air sent by the indoor blower and the working refrigerant. The first refrigerant blocking means for blocking the first refrigerant path connecting the outdoor unit and the indoor unit, the second refrigerant blocking means for blocking the second refrigerant path connecting the outdoor unit and the indoor unit, and the above. A state detecting means for estimating the state of the operating refrigerant of the indoor unit, a refrigerant storage means arranged between the expansion valve and the first refrigerant blocking means, the first refrigerant blocking means and the second refrigerant. A control means for controlling the operation of the device including the operation of the shutoff means is provided, the first refrigerant shutoff means is closed when the operation is stopped, the operating refrigerant is collected in the outdoor unit, and the second refrigerant shutoff means is closed. The expansion valve is closed, the first refrigerant shutoff means is opened, and then the first refrigerant shutoff means is closed again.

As a result, after the working refrigerant is recovered, a predetermined amount of working refrigerant can be discharged, and an appropriate amount of working refrigerant can be left in the refrigerant circuit of the indoor unit to stop.

Therefore, even if the working refrigerant leaks on the indoor side, the amount of leakage is minimized, and the piping connecting the indoor unit and the outdoor unit is prevented from being deformed by a slight external force, which is safe and reliable. An air conditioner can be provided.

A second aspect of the invention is the first aspect of the invention, wherein the state detecting means is composed of a refrigerant pressure detecting means and an indoor refrigerant temperature detecting means, and the controlling means is based on the output of the state detecting means. It controls the refrigerant shutoff means, the second refrigerant shutoff means, or the expansion valve.

As a result, it is possible to quickly determine the end of recovery of the working refrigerant on the indoor side.

Therefore, it is possible to shorten the recovery operation time of the refrigerant on the indoor side and prevent the negative pressure in the circuit on the indoor side from being generated for a long time.

In the third aspect of the invention, in the second invention, the refrigerant pressure detecting means is provided on the indoor side of the refrigerant circuit cut off by the first refrigerant blocking means and the second refrigerant blocking means.

As a result, it is possible to accurately detect the end of recovery of the working refrigerant on the indoor side and the re-emission of an appropriate amount.

Therefore, the amount of the working refrigerant remaining in the refrigerant circuit of the indoor unit can be accurately determined.

A fourth aspect of the invention is the case where the control means estimates the state of the working refrigerant on the indoor side and determines that the amount of the refrigerant retained on the indoor side is insufficient in the first, second, and third inventions. , The following operation is repeated until the amount of refrigerant retained in the room is determined to be appropriate.

a) Open the expansion valve b) Close the expansion valve,
c) Open the first refrigerant blocking means,
d) Close the first refrigerant blocking means,
As a result, even if the lengths of the first refrigerant path and the second refrigerant path connecting the outdoor unit and the indoor unit are different, an appropriate amount of refrigerant can be left and stopped.

Therefore, control with excellent adaptability can be performed.

In the fifth aspect of the invention, in the first to fourth inventions, the working refrigerant is a flammable refrigerant.

As a result, the impact on ozone layer depletion and global warming can be minimized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 shows a configuration diagram of an air conditioner according to the first embodiment of the present invention.

As shown in FIG. 1, the air conditioner in the first embodiment is a device in which an outdoor unit 101 and an indoor unit 107 are connected in a ring shape by a pipe to circulate an operating refrigerant to perform cooling or heating.

The outdoor unit 101 is between a compressor 102 that compresses the working refrigerant, a four-way valve 103 that switches the flow of the working refrigerant discharged from the compressor 102, and the outdoor air and the working refrigerant sent by the outdoor blower 105. An outdoor heat exchanger 104 that exchanges heat and an expansion valve 106 that decompresses and expands a high-pressure working refrigerant are provided. Incidentally, the compressor 102 is an inverter drive type compressor, and the operating rotation speed can be changed according to the situation.

The indoor unit 107 is provided with an indoor heat exchanger 108 that exchanges heat between the indoor air sent by the indoor blower 109 and the working refrigerant, and cools and heats the room in order to make the room comfortable. ..

The indoor unit 107 is connected by piping at the liquid side connection port 110 and the gas side connection port 111 of the outdoor unit 101 to form a basic refrigerant circuit. In addition, in order to perform comfortable air conditioning and smooth operation, a room temperature sensor 116, an indoor refrigerant temperature sensor 117, an outside air temperature sensor 118, a compressor power sensor 119, and a control device 120 as control means are provided.

The control device 120 receives the output of all the sensors and outputs an operation command to all the operation elements. In FIG. 1, the sensor output 123 and the operation command 124 are represented by arrows, and the individual correspondence is shown. Is omitted. The control means can control, for example, the liquid side shutoff valve 112, the gas side shutoff valve 113, the compressor 102, and the expansion valve 106.

The working refrigerant to be used is not particularly limited, and any working refrigerant that can be used for freezing or forming a heat pump by using a compressor by utilizing the absorption and heat dissipation accompanying the phase change can be used.

The air conditioner of FIG. 1 has a state detecting means, and the state detecting means may be any detecting means for estimating the state of the operating refrigerant of the indoor unit, for example, a refrigerant pressure detecting means and an indoor refrigerant. Examples include a temperature detecting means, a temperature detecting means, and a compressor power detecting means. The refrigerant pressure detecting means is a means for detecting the pressure of the operating refrigerant in the refrigerant circuit, and in FIG. 1, the pressure sensor 115 corresponds to this. The indoor refrigerant temperature detecting means is a means for detecting the temperature of the working refrigerant flowing in the refrigerant circuit, and in FIG. 1, the indoor refrigerant temperature sensor 117 corresponds to this. The air temperature detecting means is a means for detecting the atmospheric temperature of the outdoor unit 101 or the indoor unit 107, and in FIG. 1, the outdoor air temperature sensor 118 and the room temperature sensor 116 correspond to this. The compressor power detecting means is a means for detecting the power consumption of the compressor 102, and in FIG. 1, the compressor power sensor 119 corresponds to this.

Further, in the air conditioner of FIG. 1, in order to minimize the leakage of the working refrigerant to improve safety and reduce the environmental load, the refrigerant recovery operation is appropriate when the operation is stopped, for example, at the end of the operation or when the working refrigerant leaks. To do. Therefore, a refrigerant shutoffing means is provided, and a liquid side shutoff valve 112 is arranged as a first refrigerant shutoff means between the expansion valve 106 which is the first refrigerant path and the liquid side connection port 110, and the expansion valve 106 and the expansion valve 106 are provided. A refrigerant storage unit 114 is arranged between the liquid-side shutoff valves 112 as a refrigerant storage means. In addition, a gas side shutoff valve 113 is arranged as a second refrigerant shutoff means between the gas side connection port 111 and the four-way valve 103, which are the second refrigerant paths, and is between the gas side connection port 111 and the gas side shutoff valve 113. A pressure sensor 115 is arranged in the indoor unit 107, and a refrigerant sensor 125 is arranged in the indoor unit 107.

In FIG. 1, the four-way valve 103 is in a state during cooling operation, defrosting operation, or refrigerant recovery operation, and the working refrigerant discharged from the compressor 102 is the outdoor heat exchanger 104 from the four-way valve 103, and then expands. It constitutes a refrigeration cycle that flows to the valve 106, the liquid side shutoff valve 112, the liquid side connection port 110, and the indoor heat exchanger 108.

In the case of heating operation, the working refrigerant discharged from the compressor 102 is the indoor heat exchanger 108 from the four-way valve 103 via the gas side shutoff valve 113 and the gas side connection port 111, and then the liquid side connection port 110 and the liquid side. It constitutes a heat pump cycle that flows to the shutoff valve 112 and the outdoor heat exchanger 104.

In order to recover the working refrigerant to the outdoor unit 101 using the compressor 102, it is necessary to configure and operate the refrigeration cycle.

When the refrigerant recovery operation is instructed by the control device 120, the rotation speed of the compressor 102 is set to a predetermined value, and the refrigerant recovery operation is performed. After temporarily stopping during the heating operation, the setting of the four-way valve 103 is set in the same manner as during the cooling operation, and the refrigerant recovery operation is started. During the operation in the refrigerating cycle in which the indoor heat exchanger 108 flows in this order, the refrigerant recovery operation is continuously advanced without stopping.

When the liquid side shutoff valve 112 is closed after shifting to the refrigerant recovery operation and a predetermined time has elapsed, the supply of the working refrigerant into the refrigerant circuit of the indoor unit 107 is stopped, and the compressor 102 continues to operate. The working refrigerant in the refrigerant circuit of the above is sucked and collected in the refrigerant circuit of the outdoor unit 101, most of which is condensed in the outdoor heat exchanger 104 and stored in the outdoor heat exchanger 104, and also in the refrigerant storage unit 114. An amount of refrigerant corresponding to the volume is stored.

The refrigerant storage unit 114 as a refrigerant storage means stores the amount of working refrigerant to be opened in the refrigerant circuit of the indoor unit 107. Therefore, by opening the working refrigerant in the refrigerant storage unit 114, the working refrigerant can be left in the refrigerant circuit of the indoor unit 107 with high reproducibility accuracy. It should be noted that the refrigerant storage unit 114 is not intended to store a large amount of working refrigerant, and the liquid refrigerant is also stored in the piping unit, so the volume may be sufficient including the storage piping unit.

As the refrigerant recovery operation progresses, the output of the pressure sensor 115 decreases and the output of the indoor refrigerant temperature sensor 117 decreases, but when the liquid refrigerant in the detection unit runs out, it starts to increase and slowly increases up to the ambient temperature. To go.

Although a decrease in pressure can be detected only by the output of the pressure sensor 115, how much liquid refrigerant remains in the refrigerant circuit of the indoor unit 107 is not always the same depending on the installation state and the difference in room temperature. ..

Further, it is difficult to judge only by the output of the indoor refrigerant temperature sensor 117, and even if the output value of the indoor refrigerant temperature sensor 117 is determined, the liquid from the liquid side connection pipe 121 depends on the installation state and the operating condition of the liquid side connection pipe 121. It is difficult to determine how much liquid refrigerant remains up to the side shutoff valve 112.

If a large amount of liquid refrigerant remains, there is a risk of ignition if it leaks, and conversely, if the pressure inside the refrigerant circuit becomes negative, air will be mixed in or the pressure will become negative due to some work. There is a risk that external force will be applied to the liquid side connection pipe 121 and the gas side connection pipe 122 to cause deformation.

Therefore, using the outputs of both the pressure sensor 115 and the indoor refrigerant temperature sensor 117, the output of the pressure sensor 115 is smaller than a predetermined value, the output of the indoor refrigerant temperature sensor 117 changes from a decrease to an increase, and the temperature sensor 116 and the room temperature sensor 116 are used. The gas side shutoff valve 113 is closed and the compressor 102, the outdoor blower 105, and the indoor blower 109 are stopped, with the condition that the difference is within a predetermined value as a condition for completing the recovery of the refrigerant. At this point, there is almost no working refrigerant in the refrigerant circuit of the indoor unit 107.

Then, the expansion valve 106 is subsequently closed, the liquid side shutoff valve 112 is opened, the refrigerant held in the refrigerant storage unit 114 or the like is reopened, and when the liquid side shutoff valve 112 is stabilized, the liquid side shutoff valve 112 is closed again. As a result, the inside of the refrigerant circuit on the indoor unit 107 side is filled with a certain amount of gas refrigerant, and when a refrigerant leak occurs on the indoor side, the working refrigerant in the outdoor unit 101 does not leak, so that the working refrigerant leaks. It can be kept to a minimum to improve safety and reduce the environmental load.

Here, the operation of closing the expansion valve 106 does not have to be performed after the gas side shutoff valve 113 is closed as long as the recovery of the refrigerant has progressed and the recovery is about to end.

As a result of reopening the working refrigerant, a predetermined positive pressure is applied to the refrigerant circuit on the indoor unit 107 side, so that the liquid side connection pipe 121 and the gas side connection pipe 122 are deformed even when an external force is applied. If a refrigerant leaks during stoppage, it can be detected as an abnormal decrease in the output value of the pressure sensor 115.

Further, the indoor refrigerant temperature sensor 117 is originally a sensor for controlling the air conditioning operation of the air conditioner, and can be used for refrigerant recovery without increasing the cost.

Further, in the first embodiment, the compressor 102 is provided with the compressor power sensor 119, and when the refrigerant recovery operation proceeds, the compressor power sensor 119 is provided even if the rotation speed of the compressor 102 is constant. The output of is reduced. Although the compressor power sensor 119 is inferior in accuracy, it is often mounted on the compressor 102 for protection control, and can be configured at low cost.

The pressure sensor 115 is a suction port of the compressor 102 on the indoor unit 107 side of the refrigerant circuit shut off by the liquid side shutoff valve 112 as the first refrigerant shutoff means and the gas side shutoff valve 113 as the second refrigerant shutoff means. The minimum pressure can be detected by installing it between the gas side connection port 111 and the gas side shutoff valve 113, which are the closest to the above.

Then, the working refrigerant is collected in the outdoor unit 101, the working refrigerant is reopened once, and then the state of the working refrigerant on the indoor side is estimated. The state estimation of the working refrigerant is, for example, determining whether the pressure of the refrigerant circuit on the indoor unit 107 side is appropriate from the outputs of the pressure sensor 115, the room temperature sensor 116, the indoor refrigerant temperature sensor 117, and the like.

As a result of the determination, when it is determined that the pressure is low and the amount of refrigerant retained in the room is insufficient, the expansion valve 106 is opened for a predetermined time and then closed again, and the liquid side shutoff valve 112 is opened to store the refrigerant. The refrigerant held in the portion 114 or the like is reopened, and when it stabilizes, the liquid side shutoff valve 112 is closed again.

Then, the pressure validity determination and the operation of the valves based on the determination result are repeated until the pressure validity determination becomes appropriate.

By this operation, even if the lengths of the liquid side connection pipe 121 and the gas side connection pipe 122 connecting the indoor unit 107 and the outdoor unit 101 become long, the pressure of the refrigerant circuit on the indoor unit 107 side is appropriately maintained and is appropriate. It can be stopped with an amount of refrigerant remaining.

The air conditioner shown in the first embodiment of FIG. 1 minimizes leakage of the working refrigerant, prevents air suction, improves safety, and reduces the environmental load when any working refrigerant is used. However, when a flammable refrigerant such as R32, R1234yf, R1234ze, or a hydrocarbon such as propane or butane is used, it leads to avoiding danger such as ignition, and its effect is great.

Among them, propane has not only a small influence on global warming but also excellent performance as a refrigerant, and the significance of the present invention capable of reducing the risk of ignition is extremely high.

As described above, the air conditioner according to the present invention prevents leakage of the working refrigerant in an air conditioner that performs air conditioning using a refrigerating and heat pump cycle, and the technique is not limited to the air conditioner. It can be widely applied to water conditioners, showcases, refrigerators, etc., and has an effect.

101 Outdoor unit 102 Compressor 103 Four-way valve 104 Outdoor heat exchanger 105 Outdoor blower 106 Expansion valve 107 Indoor unit 108 Indoor heat exchanger 109 Indoor blower 110 Liquid side connection port 111 Gas side connection port 112 Liquid side shutoff valve 113 Gas side shutoff Valve 114 Refrigerant reservoir 115 Pressure sensor 116 Room temperature sensor 117 Indoor refrigerant temperature sensor 118 Outside temperature sensor 119 Compressor power sensor 120 Control device 121 Liquid side connection piping 122 Gas side connection piping 123 Sensor output 124 Operation command 125 Refrigerant sensor

Claims (5)

A compressor that compresses and sends out the working refrigerant, an outdoor heat exchanger that exchanges heat between the outdoor air sent by the outdoor blower and the working refrigerant, and an outdoor unit having an expansion valve that decompresses and expands the working refrigerant. ,
An indoor unit having an indoor heat exchanger that exchanges heat between the indoor air sent by the indoor blower and the working refrigerant.
An air conditioner that constitutes a freezing or heat pump cycle.
A first refrigerant blocking means for blocking the first refrigerant path connecting the outdoor unit and the indoor unit,
A second refrigerant blocking means for blocking the second refrigerant path connecting the outdoor unit and the indoor unit,
A state detecting means for estimating the state of the operating refrigerant of the indoor unit, and
A refrigerant storage means arranged between the expansion valve and the first refrigerant shutoff means,
A control means for controlling the operation of the device including the operation of the first refrigerant shutoff means and the second refrigerant shutoff means is provided.
When the operation is stopped, the first refrigerant blocking means is closed to collect the operating refrigerant in the outdoor unit, the second refrigerant blocking means is closed, the expansion valve is closed, and then the first refrigerant blocking means is closed. An air conditioner characterized in that the first refrigerant blocking means is closed again after being opened. The state detecting means is composed of a refrigerant pressure detecting means and an indoor refrigerant temperature detecting means, and the control means is based on the output of the state detecting means, the first refrigerant blocking means, the second refrigerant blocking means or the said. The air conditioner according to claim 1, wherein the expansion valve is controlled. The air conditioner according to claim 2, wherein the refrigerant pressure detecting means is installed on the indoor side of a refrigerant circuit cut off by the first refrigerant blocking means and the second refrigerant blocking means. Further, the control means estimates the state of the working refrigerant on the indoor side, and when it is determined that the refrigerant holding amount on the indoor side is insufficient, it is determined that the refrigerant holding amount on the indoor side is appropriate for the following operation. Repeat until a) Open the expansion valve,
b) Close the expansion valve,
c) Open the first refrigerant blocking means,
d) Close the first refrigerant blocking means,
The air conditioner according to any one of claims 1 to 3, wherein the air conditioner is characterized by the above. The air conditioner according to any one of claims 1 to 4, wherein the working refrigerant is a flammable refrigerant.

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