JP2022010435A - Air conditioner - Google Patents

Abstract

To solve problems relating to safety or reliability in refrigerant recovery operation of a conventional air conditioner which performs refrigerant recovery operation during stopping or refrigerant leakage.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 working refrigerant of an indoor unit, and control means for controlling operation of a device. The state detecting means includes at least two of refrigerant temperature detecting means, refrigerant pressure detecting means, air temperature detecting means, and compressor power detecting means. Timing of closing the second refrigerant shut-off means is determined on the basis of output of the state detecting means when recovering the working refrigerant to the outdoor unit.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, hydrocarbons such as propane and butane, etc., have double bonds in the molecular structure of artificially synthesized chlorofluorocarbons, and are short in the atmosphere. Hydrofluoroolefins (HFOs), which decompose over 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.

In addition, since R1234yf and R1234ze have a high boiling point and a large pressure loss, there is a difficulty in operating efficiency when used in a separate air conditioner such as a room air conditioner, and a multi air conditioner for buildings that uses a large amount of refrigerant, etc. Then, 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.

Many inventions have been made conventionally as a technique for improving the safety of a separate air conditioner such as a room air conditioner or a packaged air conditioner using a flammable refrigerant.

One of them is a technology for collecting flammable refrigerant in an outdoor unit to prevent the refrigerant from leaking into the room. Refrigerant leakage prevention is a very important issue in terms of environmental impact even for Freon gas currently in use, and refrigerant leakage in air conditioners must be avoided regardless of whether it is flammable or non-flammable.

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. 3 shows a first embodiment of the air exchanger described in Patent Document 1, in which the indoor unit 14 and the outdoor unit 10 attached to the chamber 11 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 refrigerant recovery 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. Then, the gas leak alarm is output at the same time when the compressor 1 is stopped.

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 method of the refrigerant recovery operation, 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 performed 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. An air conditioner that constitutes a refrigeration or heat pump cycle with an outdoor unit having a exchanger 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. A first refrigerant blocking means for blocking the first refrigerant path connecting the outdoor unit and the indoor unit, and a second refrigerant blocking means for blocking the second refrigerant path connecting the outdoor unit and the indoor unit. A state detecting means for acquiring information for estimating the state of the operating refrigerant of the indoor unit, and a control means for controlling the operation of the device including the operations of the first refrigerant blocking means and the second refrigerant blocking means are provided. The state detecting means includes at least two or more of a refrigerant temperature detecting means, a refrigerant pressure detecting means, a temperature detecting means, and a compressor power detecting means, and the control means uses the working refrigerant when the operation is stopped or the working refrigerant leaks. When collecting the refrigerant in the outdoor unit, the time to close the second refrigerant blocking means is determined based on the output of the state detecting means.

As a result, it is possible to appropriately determine when to close the second refrigerant blocking means, and to leave an appropriate amount of the working refrigerant in the refrigerant circuit of the indoor unit to stop the second refrigerant.

Since the air conditioner of the present invention can appropriately determine when to close the second refrigerant shutoff means and leave an appropriate amount of working refrigerant in the refrigerant circuit of the indoor unit to stop the air conditioner, the indoor unit side can stop the air conditioner. Even if the working refrigerant leaks, the amount of leakage is minimized, air is drawn into the refrigerant circuit to prevent the compressor from exploding, and the piping connecting the indoor unit and the outdoor unit has a slight external force. It is possible to provide a safe and highly reliable air conditioner with a small environmental load by preventing the air conditioner from being deformed.

Configuration diagram of the air conditioning harmonizer according to the first embodiment of the present invention Flow chart at the time of refrigerant recovery of the air-conditioning harmonizer of Embodiment 1 of this invention Configuration diagram of a conventional air conditioner

The first invention comprises a compressor that compresses and sends out the working refrigerant, an outdoor unit having an outdoor heat exchanger that exchanges heat between the outdoor air sent by the outdoor blower and the working refrigerant, and an indoor blower. An air conditioner that constitutes a refrigeration or heat pump cycle with an indoor unit having an indoor heat exchanger that exchanges heat between the indoor air and the working refrigerant, and connects the outdoor unit and the indoor unit. To estimate the state of the operating refrigerant of the indoor unit, the first refrigerant blocking means for blocking the first refrigerant path, the second refrigerant blocking means for blocking the second refrigerant path connecting the outdoor unit and the indoor unit. The state detecting means includes a state detecting means for acquiring the information of the above, and a control means for controlling the operation of the device including the operation of the first refrigerant shutting off means and the second refrigerant shutting off means, and the state detecting means includes a refrigerant temperature detecting means and a refrigerant. The control means includes at least two or more of a pressure detecting means, a temperature detecting means, and a compressor power detecting means, and the control means is said to be a state detecting means when the working refrigerant is collected in the outdoor unit when the operation is stopped or the working refrigerant leaks. The time to close the second refrigerant blocking means is determined based on the output of the above.

As a result, the time to close the second refrigerant shutoff means can be appropriately determined, and an appropriate amount of the 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 unit 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 and provide a safe and reliable air conditioner.

The second invention uses the refrigerant temperature detecting means and the refrigerant pressure detecting means as the state detecting means in the first invention, and the refrigerant temperature detecting means and the refrigerant pressure detecting means are both the first. It is installed on the indoor side of the refrigerant circuit cut off by the refrigerant cutoff means and the second refrigerant cutoff means.

This makes it possible to accurately estimate the state of the operating refrigerant on the indoor unit side.

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

According to a third aspect of the invention, in the first and second inventions, the control means controls the rotation speed of the compressor according to the output of the refrigerant pressure detecting means.

As a result, the recovery speed of the working refrigerant can be reduced near the end of the refrigerant recovery operation, and the accuracy of determining the shutoff time can be improved.

Therefore, it is possible to improve the reproducibility of the amount of residual working refrigerant in the refrigerant circuit of the indoor unit.

In the fourth invention, in the first, second, and third inventions, the working refrigerant is a flammable refrigerant.

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

Therefore, it is possible to provide an air conditioner that is safe and has a small environmental load.

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.

FIG. 2 is a flow chart showing an outline of control when the air conditioner according to the first embodiment of the present invention recovers the refrigerant.

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 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 endothermic heat absorption due to a phase change can be used.

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, and the compressor 102.

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 temperature detecting means and a refrigerant pressure. Examples thereof include a detecting means, a temperature detecting means, and a compressor power detecting means, and preferably, at least two or more of them are installed. The 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 refrigerant temperature sensor 114 and the indoor refrigerant temperature sensor 117 correspond to this. 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 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 shutoff 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 liquid side shutoff valve is provided. A refrigerant temperature sensor 114 is arranged between the 112 and the liquid side connection port 110. 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 sent from the four-way valve 103 to the outdoor heat exchanger 104 and then to the outdoor heat exchanger 104. It constitutes a refrigeration cycle that flows to the expansion 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 sent from the four-way valve 103 to the indoor heat exchanger 108 via the gas side shutoff valve 113 and the gas side connection port 111, and then to the liquid side connection port 110 and the liquid. It constitutes a heat pump cycle that flows to the side 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.

As shown in FIG. 2, 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 refrigerating cycle in which the refrigerant flows from the compressor 102 through the outdoor heat exchanger 104 to the indoor heat exchanger 108 in this order, such as in the cooling operation and the defrosting operation, 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, and most of them are condensed and stored in the outdoor heat exchanger 104.

As the refrigerant recovery operation progresses, the output of the pressure sensor 115 decreases, and the outputs of the refrigerant temperature sensor 114 and the indoor refrigerant temperature sensor 117 decrease, but when the liquid refrigerant in the detection unit runs out, the output starts to increase and the ambient temperature is increased. It slowly rises to the upper limit.

The change in the output of the refrigerant temperature sensor 114 and the indoor refrigerant temperature sensor 117 proceeds faster in the indoor refrigerant temperature sensor 117, reaches the lowest value first, and starts to rise. The refrigerant temperature sensor 114 is the furthest from the suction port of the compressor 102, and the output change reaches the lowest value at the latest.

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. ..

It is difficult to make a judgment only by the output of one of the refrigerant temperature sensor 114 or the indoor refrigerant temperature sensor 117, and even if it is determined by the output value of the indoor refrigerant temperature sensor 117, the liquid depends on the installation state and operating condition of the liquid side connection pipe 121. It is difficult to determine how much liquid refrigerant remains between the side connection pipe 121 and the liquid side shutoff valve 112. When judging only by the output of the refrigerant temperature sensor 114, there is a high possibility that the inside of the refrigerant circuit of the indoor unit 107 becomes a negative pressure after confirming the minimum output value.

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 and a diesel explosion will occur inside the compressor 102. Or, if oxygen or moisture adversely affects the reliability of the device, or if an external force is applied to the liquid side connection pipe 121 or gas side connection pipe 122 that has become negative pressure due to some work, deformation easily occurs. There is a risk of getting rid of it.

Therefore, instead of determining the refrigerant recovery end timing with a single sensor output, if the refrigerant recovery end timing is determined comprehensively from a plurality of sensor outputs, the residual amount of refrigerant in the refrigerant circuit of the indoor unit 107 can be determined. It can be controlled accurately.

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.

Further, even when the pressure sensor 115 is used, the compressor power sensor 119 can serve as a substitute even if a defect occurs in the pressure sensor 115, and high reliability can be obtained.

Here, a combination of sensors and an actual example of the refrigerant recovery operation will be described.

First, as a basic combination, a combination of the pressure sensor 115 as the refrigerant pressure detecting means and the refrigerant temperature sensor 114 or the indoor refrigerant temperature sensor 117 as the refrigerant temperature detecting means can be considered.

After the start of the refrigerant recovery operation, the output of the pressure sensor 115 gradually decreases. At this time, the refrigerant recovery operation is basically completed by reducing the amount of liquid refrigerant in the refrigerant circuit in the indoor unit 107 as much as possible before the output of the pressure sensor 115 becomes a negative pressure.

As the refrigerant recovery operation progresses, the output of the pressure sensor 115 decreases, and the output of the refrigerant temperature sensor 114 or the indoor refrigerant temperature sensor 117 also decreases. Before the output of the pressure sensor 115 becomes negative pressure, when the output of the refrigerant temperature sensor 114 or the indoor refrigerant temperature sensor 117 starts to rise, when the output of the pressure sensor 115 reaches a predetermined value, the refrigerant recovery is completed and the gas is recovered. The side shutoff valve 113 is closed, and the compressor 102, the outdoor blower 105, and the indoor blower 109 are stopped.

The refrigerant temperature sensor 114 and the indoor refrigerant temperature sensor 117 are superior from the viewpoint of accurately recovering the refrigerant, but the indoor refrigerant temperature sensor 117 is generally arranged for the purpose of controlling the air conditioner. It is also possible to substitute a pipe temperature sensor, and in many cases, the increase in cost can be suppressed.

Further, if the compressor power sensor 119 is used as the compressor power detection means instead of the pressure sensor 115, the detection accuracy of the refrigerant pressure is lowered, but the current value is used for the control in the compressor such as the one using the DC brushless motor. Since it can be detected without any special cost, it is possible to suppress the increase in cost.

Immediately after the start of the refrigerant recovery operation, the refrigerant recovery to the outdoor unit 101 has not yet progressed, and when the pressure of the suction refrigerant of the compressor 102 is high, the power of the compressor 102 is also high, but the refrigerant recovery is performed. If the pressure of the suction refrigerant of the compressor 102 decreases, the power of the compressor also decreases. Therefore, the output of the pressure sensor 115 can be replaced with the output of the compressor power sensor 119, and the progress state of the refrigerant recovery can be estimated in the same manner.

Further, an appropriate refrigerant recovery operation can be performed by using the pressure sensor 115 or the compressor power sensor 119, the room temperature sensor 116 and the outside air temperature sensor 118 as the temperature detecting means, and the refrigerant temperature sensor 114 or the indoor refrigerant temperature sensor 117. It is possible.

By using the outputs of the room temperature sensor 116 and the outside air temperature sensor 118, the temperature of the working refrigerant in the outdoor room can be estimated together with the rotation speed of the compressor 102, and the power consumption of the compressor 102 can be estimated.

If the air conditioner is normal, the output value of the compressor power sensor 119 generally matches the estimated value of power consumption, but if the circulation of the refrigerant is stopped or the heat exchange with the indoor or outdoor air is hindered. , A big discrepancy occurs.

At the time of refrigerant recovery, the circulation of the refrigerant is stopped by the liquid side shutoff valve 112, so that the output value of the compressor power sensor 119 decreases and becomes smaller than the estimated value as the refrigerant recovery progresses.

By comparing the estimated power consumption of the compressor 102 with the output value of the compressor power sensor 119, the progress of refrigerant recovery can be estimated more accurately.

Here, if the shape of the mounting portion of the indoor refrigerant temperature sensor 117 and the refrigerant temperature sensor 114 is such that, for example, the refrigerant falls vertically and then rises vertically, and the structure is such that the liquid refrigerant can easily be stored, the evaporation of the liquid refrigerant is completed. Can be detected more accurately.

In addition, the refrigerant temperature sensor 114 and the pressure sensor 115 include a liquid side shutoff valve 112 as a first refrigerant shutoff means and a gas side shutoff valve 113 as a second refrigerant shutoff means for the purpose of accurately recovering the refrigerant. It is preferably arranged on the indoor unit 107 side of the cut-off refrigerant circuit. The mounting position of the refrigerant temperature sensor 114 captures the moment when the final liquid refrigerant evaporates when the liquid refrigerant remains until the end, that is, between the liquid side connection port 110 and the liquid side shutoff valve 112. be able to. The pressure sensor 115 is installed on the refrigerant circuit side of the indoor unit 107 between the gas side connection port 111 and the gas side shutoff valve 113, which are closest to the suction port of the compressor 102, to detect the minimum pressure. Can be done.

That is, by arranging the refrigerant temperature sensor 114 and the pressure sensor 115 at the positions shown in FIG. 1, the refrigerant can be recovered most accurately.

Further, considering the rotation speed of the compressor 102 at the time of refrigerant recovery, if the rotation speed is high, the refrigerant recovery operation can be completed in a short time, but the timing of the refrigerant recovery end command is from an appropriate end timing. Even a slight deviation causes a large variation in the remaining amount of working refrigerant in the refrigerant circuit on the indoor unit 107 side.

On the other hand, if the rotation speed is low, the working refrigerant is slowly recovered, so that the timing of the refrigerant recovery end command is less likely to deviate from the appropriate end timing, and the remaining amount of the working refrigerant in the refrigerant circuit on the indoor unit 107 side is reduced. It is easy to keep it properly, but it is not preferable because it takes a long time to recover the refrigerant.

Therefore, an appropriate rotation speed that is neither high nor low may be set. Preferably, the compressor 102 is driven at a high rotation speed at the start of the refrigerant recovery operation, and when the refrigerant recovery progresses and the end of the operation is approaching, the rotation speed is reduced. As a result, it is possible to easily maintain the remaining amount of the working refrigerant in the refrigerant circuit on the indoor unit 107 side while suppressing the time required for the refrigerant recovery operation.

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 is an air conditioner that performs air conditioning using a refrigerating and heat pump cycle to prevent leakage of a refrigerant, and the technique thereof is not limited to the air conditioner and supplies hot water. It can be widely applied to machines, 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 temperature sensor 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 pipe 122 Gas side connection pipe 123 Sensor output 124 Operation command

Claims (4)

A compressor that compresses and sends out the working refrigerant, and an outdoor unit having an outdoor heat exchanger that exchanges heat between the outdoor air sent by the outdoor blower and 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 acquiring information for estimating the state of the operating refrigerant of the indoor unit, and
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.
The state detecting means includes at least two or more of a refrigerant temperature detecting means, a refrigerant pressure detecting means, a temperature detecting means, and a compressor power detecting means.
The control means is characterized in that when the working refrigerant is collected in the outdoor unit when the operation is stopped or the working refrigerant leaks, the time to close the second refrigerant blocking means is determined based on the output of the state detecting means. Air conditioner. The first aspect of claim 1, wherein the refrigerant temperature detecting means and the refrigerant pressure detecting means are provided on the indoor side of a refrigerant circuit cut off by the first refrigerant blocking means and the second refrigerant blocking means. Air conditioner. The air conditioner according to claim 1 or 2, wherein the control means controls the rotation speed of the compressor according to the output of the refrigerant pressure detecting means. The air conditioner according to any one of claims 1 to 3, wherein the working refrigerant is a flammable refrigerant.

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