JP6297151B2 - Refrigeration cycle apparatus, refrigerant leak detection apparatus and refrigerant leak detection method - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus having a function capable of detecting refrigerant leakage from the refrigerant circuit, a refrigerant leakage detection apparatus that detects refrigerant leakage from the refrigerant circuit of the refrigeration cycle apparatus, and a refrigeration cycle apparatus. The present invention relates to a refrigerant leak detection method for detecting refrigerant leak from a refrigerant circuit.

  Conventionally, the refrigerant density of each element is calculated from the detection results of the pressure sensor and temperature sensor used to control each element (drive device (actuator) such as a compressor or an expansion valve) constituting the refrigeration cycle, and the contents of each element There is a refrigeration cycle apparatus that detects leakage of refrigerant from the refrigerant circuit of the refrigeration cycle apparatus by calculating the amount of refrigerant in the refrigerant circuit by integrating the products (see, for example, Patent Document 1).

  In addition, there is a refrigerant filling amount shortage detection device for an air conditioner that detects a refrigerant shortage by the pressure of a refrigerant circuit when stopped (see, for example, Patent Document 2).

JP 2010-236714 A (page 26, FIG. 8 etc.) Japanese Patent Laid-Open No. 3-11278 (first page, FIG. 1 etc.)

  In a refrigeration cycle apparatus such as a refrigeration air conditioner, the amount of refrigerant required for operation varies depending on operating conditions, and therefore, a liquid reservoir container that stores excess refrigerant may be installed in the refrigerant circuit. This liquid reservoir is installed on the high pressure side or low pressure side of the refrigerant circuit. When detecting refrigerant leakage from the refrigerant circuit, it is necessary to calculate the refrigerant amount of each element constituting the refrigeration cycle apparatus.

In the element equipment other than the liquid storage container, it is possible to estimate the refrigerant state from the sensor measurement values such as the existing pressure and temperature used for the operation of the refrigeration cycle apparatus. Is possible.
On the other hand, since the state of the refrigerant amount in the liquid reservoir does not change due to the difference in the refrigerant amount, the refrigerant amount cannot be calculated from the existing sensor measurement values. For this reason, in the liquid storage container, abnormalities, that is, refrigerant shortage and refrigerant leakage have been detected after the internal state of the liquid storage container has changed, for example, the liquid refrigerant in the liquid storage container is exhausted.

  However, there are many states in which the amount of liquid refrigerant present in the liquid reservoir is half or more of the total filling amount, and a method as described in Patent Document 1 for detecting refrigerant leakage after the excess liquid refrigerant is exhausted Then, a large amount of refrigerant will leak into the air.

  In addition, since the pressure does not change unless a large amount of refrigerant leaks from the refrigerant circuit, even a method such as that described in Patent Document 2 that detects leakage with the pressure of the refrigerant circuit leaks a large amount of refrigerant into the air. It will be.

  The present invention has been made in view of such points, and a refrigeration cycle apparatus, a refrigerant leak detection apparatus, and a refrigerant that can easily and reliably detect the amount of liquid refrigerant in a liquid storage container and enable early detection of refrigerant leakage. An object is to provide a leak detection method.

The refrigeration cycle apparatus according to the present invention is a refrigeration cycle apparatus having a refrigerant circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a liquid storage container are connected by piping, and the amount of liquid refrigerant in the liquid storage container A liquid level detection sensor for detecting the amount of liquid refrigerant in the liquid storage container when a predetermined time has elapsed since the compressor was stopped, and the opening level of the expansion valve is predetermined. When the value is smaller than the value, the refrigerant circuit as a whole is calculated from the refrigerant amount of each element device other than the liquid reservoir before the compressor is stopped and the refrigerant amount of the liquid reservoir after the compressor is stopped. And a refrigerant leakage detection device that determines the presence or absence of refrigerant leakage from the refrigerant circuit by calculating the amount of refrigerant and comparing it with a predetermined reference value.

The refrigerant leak detection apparatus according to the present invention is a refrigerant leak detection apparatus for detecting refrigerant leak from a refrigerant circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a liquid storage container are connected by piping. And a surplus of the liquid storage container based on information from the measurement unit, and a measurement unit that detects an operation state amount of the refrigerant circulating in the refrigerant circuit based on the liquid refrigerant amount. A surplus liquid refrigerant amount calculating unit that calculates the amount of liquid refrigerant; and when the opening of the expansion valve is smaller than a predetermined value, the refrigerant amount of each element device other than the liquid reservoir before the compressor is stopped, and By calculating the refrigerant amount of the entire refrigerant circuit from the calculation result of the surplus liquid refrigerant amount calculation unit when a predetermined time has passed since the compressor stopped, and comparing this with a predetermined reference value, A determination unit for determining whether or not there is a refrigerant leak from the refrigerant circuit. Those were.

The refrigerant leakage detection method according to the present invention is a refrigerant leakage detection method for detecting refrigerant leakage from a refrigerant circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a liquid storage container are connected by piping, and the liquid storage container The amount of liquid refrigerant is detected, the amount of operating state of the refrigerant circulating in the refrigerant circuit is measured based on the amount of liquid refrigerant, and the amount of excess liquid refrigerant in the reservoir is calculated from the measurement result. When the opening degree of the expansion valve is smaller than a predetermined value, the refrigerant amount of each element device other than the liquid reservoir container before the compressor stops, and when a predetermined time has elapsed since the compressor stopped The refrigerant amount of the entire refrigerant circuit is calculated from the excess liquid refrigerant amount, and this is compared with a predetermined reference value. When the calculated result is smaller than the reference value, the refrigerant leaks from the refrigerant circuit. It is determined that

  According to the refrigeration cycle device, the refrigerant leakage detection device, and the refrigerant leakage detection method according to the present invention, after a predetermined time has elapsed since the compressor stopped, by detecting the amount of liquid refrigerant in the liquid storage container, In addition, refrigerant leakage can be detected reliably, and refrigerant leakage can be detected early.

It is a schematic block diagram which shows an example of the refrigerant circuit structure of the refrigeration air conditioning apparatus which concerns on embodiment of this invention. It is a block diagram of the state which developed the functional composition of the liquid level detection device and refrigerant leak detection device of the refrigerating and air-conditioning device concerning an embodiment of the invention. It is a ph diagram at the time of air_conditionaing | cooling operation of the refrigerating and air-conditioning apparatus which concerns on embodiment of this invention. It is a ph diagram at the time of heating operation of the refrigerating and air-conditioning apparatus concerning an embodiment of the invention. It is the figure which showed the time passage data of the refrigerant | coolant amount of the liquid reservoir container when a compressor is stopped in a certain predetermined time. It is the figure which showed the time passage data of the refrigerant | coolant amount of the outdoor heat exchanger when a compressor is stopped in a certain predetermined time. It is the figure which showed the time passage data of the refrigerant | coolant amount of a liquid pipe when a compressor is stopped at a certain predetermined time. It is the figure which showed the time passage data of the refrigerant | coolant amount of a gas pipe when a compressor is stopped at a certain predetermined time. It is the figure which showed the time passage data of the refrigerant | coolant amount of an indoor heat exchanger when a compressor is stopped in a predetermined time. It is the figure which showed the time passage data of the refrigerant | coolant amount of the liquid storage container when a compressor is stopped in a certain predetermined time on the conditions which changed 3 types of outside temperature. It is the figure which showed the time passage data of the refrigerant | coolant amount of an outdoor heat exchanger when a compressor is stopped in a certain predetermined time on the conditions which changed 3 types of outside temperature. It is the figure which showed the time passage data of the refrigerant | coolant amount of a liquid storage container when a compressor is stopped in a certain predetermined time on the conditions which changed the installation conditions of an outdoor unit and an indoor unit. It is the figure which showed the time passage data of the refrigerant | coolant amount of the liquid reservoir outdoor heat exchanger when a compressor is stopped in a certain predetermined time on the conditions which changed three types of installation conditions of the outdoor unit and the indoor unit. . It is the figure which showed the time passage data of the frequency of the compressor when the compressor is stopped at a certain predetermined time A, the low pressure inside the liquid reservoir, the saturation temperature, the gas phase temperature, and the liquid phase temperature. The compressor is stopped at a predetermined time A, and the time frequency data of the compressor frequency and the low-pressure pressure, saturation temperature, gas phase temperature, and liquid phase temperature inside the liquid storage container when the predetermined time has elapsed since then. FIG. The outside air temperature is added to the data shown in FIG. It is a flowchart which shows the flow of the refrigerant | coolant leak detection process in the refrigeration air conditioning apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of calculation of the liquid refrigerant | coolant amount in the liquid storage container of step S002 of FIG. 17 of the refrigerant | coolant leak detection process in the refrigerating and air-conditioning apparatus which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one. Further, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and this is common throughout the entire specification. Furthermore, the forms of the constituent elements shown in the entire specification are merely examples, and are not limited to these descriptions. Hereinafter, a refrigeration air conditioner will be described as an example of the refrigeration cycle apparatus.

  FIG. 1 is a schematic configuration diagram illustrating an example of a refrigerant circuit configuration of a refrigerating and air-conditioning apparatus 1 according to an embodiment of the present invention. Based on FIG. 1, the refrigerant circuit configuration and operation of the refrigerating and air-conditioning apparatus 1 will be described. The refrigeration air conditioner 1 is installed in, for example, a building or a condominium, and is used for cooling or heating an air-conditioning target area such as a room to be installed by performing a vapor compression refrigeration cycle operation.

<Configuration of refrigeration air conditioner 1>
The refrigerating and air-conditioning apparatus 1 mainly includes an outdoor unit 2 as a heat source unit and an indoor unit 4 (indoor unit 4A, 2) as a unit of use of a plurality of units (two are shown in FIG. 1) connected in parallel thereto. Indoor unit 4B). The refrigerating and air-conditioning apparatus 1 also has refrigerant extension pipes (liquid side extension pipes 6 and gas side extension pipes 7) that connect the outdoor unit 2 and the indoor unit 4. That is, the refrigerating and air-conditioning apparatus 1 has the refrigerant circuit 10 in which the outdoor unit 2 and the indoor unit 4 are connected by the refrigerant pipe and the refrigerant circulates.

The liquid side extension pipe 6 is a pipe through which the liquid refrigerant passes, and connects the outdoor unit 2 and the indoor unit 4. The liquid side extension pipe 6 is configured by connecting a liquid main pipe 6A, a liquid branch pipe 6a, a liquid branch pipe 6b, and a distributor 51a.
The gas side extension pipe 7 is a pipe through which the gas refrigerant passes, and connects the outdoor unit 2 and the indoor unit 4. The gas side extension pipe 7 is configured by connecting a gas main pipe 7A, a gas branch pipe 7a, a gas branch pipe 7b, and a distributor 52a.

[Refrigerant]
As the refrigerant filled in the refrigerant circuit 10, an azeotropic refrigerant having the same saturated gas temperature and the saturated liquid temperature or a pseudo-azeotropic refrigerant having the same saturated gas temperature and the saturated liquid temperature can be used.
Alternatively, a non-azeotropic refrigerant may be used as the refrigerant filled in the refrigerant circuit 10.
That is, the refrigerant filled in the refrigerant circuit 10 is not particularly limited.

[Indoor unit 4]
The indoor unit 4A and the indoor unit 4B are supplied with cooling air or heating air from the outdoor unit 2 and supply cooling air or heating air to the air-conditioning target area. In the following description, “A” and “B” after the indoor unit 4 may be omitted. In this case, both the indoor unit 4A and the indoor unit 4B are shown. Further, “A (or a)” is added after the sign of each device (including part of the circuit) in the “indoor unit 4A” system, and each device (including part of the circuit) in the “indoor unit 4B” system. ) Followed by “B (or b)”. In these descriptions, “A (or a)” and “B (or b)” after the reference may be omitted, but it goes without saying that both devices are shown.

  The indoor unit 4 is installed by being embedded in a ceiling of a room such as a building, suspended, or hung on a wall surface of the room. The indoor unit 4A is connected to the outdoor unit 2 using the liquid main pipe 6A, the distributor 51a, the liquid branch pipe 6a, the gas branch pipe 7a, the distributor 52a, and the gas main pipe 7A. Is configured. The indoor unit 4B is connected to the outdoor unit 2 using the liquid main pipe 6A, the distributor 51a, the liquid branch pipe 6b, the gas branch pipe 7b, the distributor 52a, and the gas main pipe 7A. Is configured.

  The indoor unit 4 mainly has an indoor refrigerant circuit (a indoor refrigerant circuit 10a in the indoor unit 4A and an indoor refrigerant circuit 10b in the indoor unit 4B) that constitutes a part of the refrigerant circuit 10. This indoor refrigerant circuit is mainly configured by an expansion valve 41 as an expansion mechanism and an indoor heat exchanger 42 as a use side heat exchanger extending in series.

  The expansion valve 41 is installed on the liquid side of the indoor heat exchanger 42 in order to adjust the flow rate of the refrigerant flowing in the indoor refrigerant circuit, and expands the refrigerant by decompressing it. The expansion valve 41 may be configured by a valve whose opening degree can be variably controlled, for example, an electronic expansion valve.

  The indoor heat exchanger 42 functions as a refrigerant condenser (heat radiator) during heating operation to heat indoor air, and functions as a refrigerant evaporator during cooling operation to cool the indoor air. The heat exchange is performed between the air and water) and the refrigerant, and the refrigerant is condensed into liquefied or evaporated gas. The type of the indoor heat exchanger 42 is not particularly limited, and may be a cross-fin type fin-and-tube type heat exchanger composed of heat transfer tubes and a large number of fins, for example.

  The indoor unit 4 has an indoor fan 43 as a blower for supplying indoor air as supply air after sucking indoor air into the indoor unit 4 and exchanging heat with the refrigerant in the indoor heat exchanger 42. Yes. The indoor fan 43 can change the air volume of the air supplied to the indoor heat exchanger 42, and may be a centrifugal fan or a multiblade fan driven by a DC fan motor, for example. However, the indoor heat exchanger 42 may perform heat exchange with a heat medium (for example, water or brine) different from the refrigerant and air.

  The indoor unit 4 is provided with various sensors. A gas side temperature sensor (gas side temperature sensor) that detects the temperature of the refrigerant (that is, the refrigerant temperature corresponding to the condensation temperature Tc during heating operation or the evaporation temperature Te during cooling operation) is provided on the gas side of the indoor heat exchanger 42. 33f (mounted on the indoor unit 4A) and a gas side temperature sensor 33i (mounted on the indoor unit 4B)) are provided. On the liquid side of the indoor heat exchanger 42, there are a liquid side temperature sensor (a liquid side temperature sensor 33e (mounted on the indoor unit 4A) and a liquid side temperature sensor 33h (mounted on the indoor unit 4B)) for detecting the temperature Teo of the refrigerant. Is provided.

  Also, on the indoor air inlet side of the indoor unit 4, an indoor temperature sensor (an indoor temperature sensor 33g (mounted on the indoor unit 4A) that detects the temperature of the indoor air flowing into the indoor unit 4 (that is, the indoor temperature Tr)). ), An indoor temperature sensor 33j (mounted on the indoor unit 4B)).

  Information (temperature information) detected by these various sensors is sent to a control unit (indoor side control unit 32), which will be described later, which controls the operation of each device mounted in the indoor unit 4, and the operation of each device Used for control. The types of the liquid side temperature sensors 33e and 33h, the gas side temperature sensors 33f and 33i, and the indoor temperature sensors 33g and 33j are not particularly limited. That is, in the refrigerating and air-conditioning apparatus 1, the temperature of the refrigerant can be measured as necessary by each temperature sensor according to the operating state.

  Moreover, the indoor unit 4 has the indoor side control part 32 (32a, 32b) which controls operation | movement of each apparatus which comprises the indoor unit 4. FIG. The indoor control unit 32 includes a microcomputer, a memory, and the like provided to control the indoor unit 4. The indoor side control unit 32 exchanges control signals and the like with a remote controller (not shown) for individually operating the indoor unit 4, and communicates with the outdoor unit 2 (specifically, the outdoor side control unit 31). Control signals and the like can be exchanged via a transmission line (which may be wireless). That is, the indoor side control part 32 functions as the control part 3 which performs operation control of the whole refrigerating and air-conditioning apparatus 1 by cooperating with the outdoor side control part 31 (refer FIG. 2).

[Outdoor unit 2]
The outdoor unit 2 has a function of supplying cold or warm heat to the indoor unit 4. The outdoor unit 2 is installed outside a building or the like, for example, and is connected to the indoor unit 4 by a liquid side extension pipe 6 and a gas side extension pipe 7 and constitutes a part of the refrigerant circuit 10. That is, the refrigerant flowing out of the outdoor unit 2 and flowing through the liquid main pipe 6A is divided into the liquid branch pipe 6a and the liquid branch pipe 6b via the distributor 51a, and flows into the indoor unit 4A and the indoor unit 4B, respectively. It has become. Similarly, the refrigerant flowing out of the outdoor unit 2 and flowing through the gas main pipe 7A is divided into the gas branch pipe 7a and the gas branch pipe 7b via the distributor 52a, and flows into the indoor unit 4A and the indoor unit 4B, respectively. It is like that.

  The outdoor unit 2 mainly has an outdoor refrigerant circuit 10 c that constitutes a part of the refrigerant circuit 10. The outdoor refrigerant circuit 10c mainly includes a compressor 21, a four-way valve 22 as a flow path switching unit, an outdoor heat exchanger 23 as a heat source side heat exchanger, a liquid reservoir (accumulator) 24, and an open / close The valve 28 and the on-off valve 29 are configured to extend in series.

  The compressor 21 sucks in the refrigerant and compresses the refrigerant to a high temperature / high pressure state. The compressor 21 can vary its operating capacity, and may be composed of a positive displacement compressor driven by a motor whose frequency F is controlled by an inverter, for example. In FIG. 1, the case where there is one compressor 21 is illustrated as an example. However, the present invention is not limited to this, and two or more compressors 21 are arranged in parallel according to the number of connected indoor units 4. Alternatively, it may be connected and mounted.

  The four-way valve 22 switches the direction of the refrigerant flow during the heating operation and the direction of the heat source side refrigerant flow during the cooling operation. During the cooling operation, the four-way valve 22 is switched as indicated by a solid line, and connects the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 23 and connects the liquid reservoir 24 and the gas main pipe 7A side. To do. Thereby, the outdoor heat exchanger 23 functions as a condenser of the refrigerant compressed by the compressor 21, and the indoor heat exchanger 42 functions as an evaporator. The four-way valve 22 is switched as indicated by a dotted line during heating operation, and extends the discharge side of the compressor 21 and the gas main pipe 7A and connects the liquid storage container 24 and the gas side of the outdoor heat exchanger 23. . Thereby, the indoor heat exchanger 42 functions as a condenser of the refrigerant | coolant compressed by the compressor 21, and the outdoor heat exchanger 23 functions as an evaporator.

  The outdoor heat exchanger 23 functions as a refrigerant evaporator during heating operation, functions as a refrigerant condenser (radiator) during cooling operation, and heat is generated between a heat medium (for example, air or water) and the refrigerant. Exchange is performed, and the refrigerant is evaporated or condensed and liquefied. The type of the outdoor heat exchanger 23 is not particularly limited. For example, the outdoor heat exchanger 23 may be configured by a cross fin type fin-and-tube heat exchanger including heat transfer tubes and a large number of fins. The outdoor heat exchanger 23 has a gas side connected to the four-way valve 22 and a liquid side connected to the liquid main pipe 6A.

  The outdoor unit 2 has an outdoor fan 27 as a blower for sucking outdoor air into the outdoor unit 2 and exchanging heat with the refrigerant in the outdoor heat exchanger 23 and then discharging it to the outside. The outdoor fan 27 can change the air volume of air supplied to the outdoor heat exchanger 23, and may be a propeller fan driven by a motor including a DC fan motor, for example. However, the outdoor heat exchanger 23 may perform heat exchange with a heat medium (for example, water or brine) different from the refrigerant and air.

  The liquid storage container 24 is connected to the suction side of the compressor 21, and can store surplus refrigerant generated in the refrigerant circuit 10 in accordance with fluctuations in the outdoor unit 2, the indoor unit 4, and the operating load of the piping. It is a container. The liquid storage container 24 must be a pressure container that is formed of a metal such as carbon steel and is designed and manufactured in consideration of the pressure resistance in accordance with the regulations.

  In detecting refrigerant leakage from the refrigerant circuit 10, it is necessary to detect the amount of excess liquid refrigerant stored in the liquid storage container 24. It is possible to provide a transparent portion such as a viewing window in a part of the liquid storage container 24. However, practically, most of the liquid storage container 24 is an opaque container, and the liquid level inside the liquid storage container 24 is measured from the outside of the liquid storage container 24 using something similar to light, or the inside of the liquid storage container 24 is visually observed. It is impossible to see through the whole. Even if an optically transparent viewing window is attached to a part of the liquid storage container 24, the liquid level in the liquid storage container 24 is constantly changing. It is difficult to measure or monitor the exact position of the coolant level.

  The liquid reservoir 24 is provided with a liquid level detection sensor 36 for detecting the amount of liquid refrigerant inside. As the liquid level detection sensor 36, a temperature sensor that detects the liquid level by measuring the surface temperature of the liquid storage container 24 can be applied.

  As the liquid level detection sensor 36, an ultrasonic sensor that is installed outside the liquid reservoir 24 and detects the liquid level can be applied. Further, a heating temperature system in which a sensor unit is installed on the surface of the container or inside the container, the sensor is heated, and the liquid level is detected by the difference in the heat dissipation characteristics of the gas-liquid part can be applied as the liquid level detection sensor 36. Furthermore, a float type in which a float portion is installed inside the liquid storage container 24 and gas and liquid are discriminated by the operation of the float can be applied as the liquid level detection sensor 36. Furthermore, a weight system that detects a liquid amount using a measurement value that varies depending on the weight or weight of the container can be applied as the liquid level detection sensor 36.

  The on-off valve 28 and the on-off valve 29 are provided at connection ports with external devices and pipes (specifically, the liquid main pipe 6A and the gas main pipe 7A), and do not conduct the refrigerant by opening and closing. It is something to do.

  The outdoor unit 2 is provided with a plurality of pressure sensors and temperature sensors. As the pressure sensors, a suction pressure sensor 34a for detecting the suction pressure Ps of the compressor 21 and a discharge pressure sensor 34b for detecting the discharge pressure Pd of the compressor 21 are installed.

  As the temperature sensors, an intake temperature sensor 33a, a discharge temperature sensor 33b, a heat exchange temperature sensor 33k, a liquid side temperature sensor 33l, and an outdoor temperature sensor 33c are installed.

The suction temperature sensor 33 a is provided at a position between the liquid reservoir 24 and the compressor 21, and detects the suction temperature Ts of the compressor 21.
The discharge temperature sensor 33 b is provided on the discharge side of the compressor 21 and detects the discharge temperature Td of the compressor 21.
The heat exchanger temperature sensor 33k is provided in the outdoor heat exchanger 23 and detects the temperature of the refrigerant flowing in the outdoor heat exchanger 23.
The liquid side temperature sensor 33l is installed on the liquid side of the outdoor heat exchanger 23, and detects the refrigerant temperature on the liquid side of the outdoor heat exchanger 23.
The outdoor temperature sensor 33 c is installed on the outdoor air inlet side of the outdoor unit 2 and detects the temperature of the outdoor air flowing into the outdoor unit 2.

  Information (temperature information) detected by these various sensors is sent to a control unit (outdoor control unit 31) that controls the operation of each device mounted on the outdoor unit 2 to control the operation of each device. Used. In addition, although the kind of each temperature sensor is not specifically limited, For example, it is good to comprise with a thermistor etc.

  The outdoor unit 2 also has an outdoor control unit 31 that controls the operation of each element constituting the outdoor unit 2. And the outdoor side control part 31 has the inverter circuit etc. which control the microcomputer provided in order to control the outdoor unit 2, a memory, and a motor. The outdoor control unit 31 can exchange control signals and the like with the indoor control unit 32 of the indoor unit 4 via a transmission line (may be wireless). That is, the outdoor side control part 31 functions as the control part 3 which performs operation control of the whole refrigerating and air-conditioning apparatus 1 by cooperating with the indoor side control part 32 (refer FIG. 2).

(Extended piping)
The extension pipes (liquid side extension pipe 6 and gas side extension pipe 7) are pipes necessary for connecting the outdoor unit 2 and the indoor unit 4 and circulating the refrigerant in the refrigerant circuit of the refrigeration air conditioner 1.

  The extension pipe is composed of a liquid side extension pipe 6 (liquid main pipe 6A, liquid branch pipes 6a, 6b) and a gas side extension pipe 7 (gas main pipe 7A, gas branch pipes 7a, 7b). Refrigerant piping installed on site when installed at the installation location such as a building. As the extension pipe, extension pipes each having a pipe diameter determined according to the combination of the outdoor unit 2 and the indoor unit 4 are used.

  In the present embodiment, as shown in FIG. 1, a distributor 51a, a distributor 52a, and an extension pipe are used for connection between one outdoor unit 2 and two indoor units 4A and 4B. ing. For the liquid side extension pipe 6, the outdoor unit 2 and the distributor 51a are connected by a liquid main pipe 6A, and the liquid branch pipe 6a and the liquid branch pipe 6b are connected between the distributor 51a and each indoor unit 4A and the indoor unit 4B. Connect with. For the gas side extension pipe 7, the indoor unit 4A, the indoor unit 4B and the distributor 52a are connected by the gas branch pipe 7a and the gas branch pipe 7b, and the distributor 52a and the outdoor unit 2 are connected by the gas main pipe 7A. To do.

  In the present embodiment, an extension pipe in which a distributor 51a and a distributor 52a are added for connection between one outdoor unit 2 and two indoor units 4 is used. However, the distributor 51a and the distributor 52a are used. Is not necessarily required. In addition, the distributor 51a and the distributor 52a are shown by way of example using a T-shaped tube, but the present invention is not limited to this, and a header may be used. Further, when a plurality of (three or more) indoor units 4 are connected, a plurality of T-shaped tubes may be used for distribution, or a header may be used.

  As described above, the refrigerant circuit 10 is configured by connecting the indoor refrigerant circuit 10a, the indoor refrigerant circuit 10b, the outdoor refrigerant circuit 10c, and the extension pipes (the liquid side extension pipe 6 and the gas side extension pipe 7). Has been. The refrigerating and air-conditioning apparatus 1 is operated by switching the cooling operation and the heating operation by the four-way valve 22 by the control unit 3 including the indoor side control unit 32a, the indoor side control unit 32b, and the outdoor side control unit 31. At the same time, the devices of the outdoor unit 2, the indoor unit 4A, and the indoor unit 4B are controlled in accordance with the operation loads of the indoor units 4A and the indoor unit 4B.

<Control block configuration of refrigeration air conditioner 1>
FIG. 2 is a control block diagram of the refrigeration air conditioner 1. The refrigerating and air-conditioning apparatus 1 includes a liquid level detection device that detects the liquid level of the liquid storage container 24 and a refrigerant leakage detection device that detects refrigerant leakage in the refrigerant circuit 10. In FIG. 2, the block diagram of the state which expand | deployed the functional structure of the liquid level detection apparatus and the refrigerant | coolant leakage detection apparatus is shown.

  The control unit 3 includes a pressure sensor (suction pressure sensor 34a, discharge pressure sensor 34b), temperature sensor (liquid side temperature sensors 33e, 33h, gas side temperature sensors 33f, 33i, indoor temperature sensors 33g, 33j, suction temperature sensor 33a, The discharge temperature sensor 33b, the heat exchange temperature sensor 33k, the liquid side temperature sensor 33l, and the outdoor temperature sensor 33c) are connected so as to receive detection signals. The control unit 3 also controls various devices (compressor 21, outdoor fan 27, indoor fan 43, valve device (four-way valve 22, flow control valve (open / close valve 28, open / close valve 29, expansion valve) based on these detection signals). The control unit 3 is connected so that it can receive the detection signals of the liquid level detection sensors 36a to 36c installed in the liquid storage container 24. Yes.

  Moreover, the control part 3 is provided with the measurement part 3a, the excess liquid refrigerant | coolant amount calculation part 3c, the determination part 3d, the memory | storage part 3e, and the drive part 3f. The control unit 3 is also connected with an input unit 3g and an output unit 3h.

  The measuring unit 3a is configured to determine the pressure and temperature of the refrigerant circulating in the refrigerant circuit 10 based on information sent from the pressure sensors (34a, 34b) and the temperature sensors (33a to 33l, 36a to 36c) (that is, the operating state quantity). ). Moreover, the measurement part 3a comprises the "measurement part" of this invention with a pressure sensor (34a, 34b) and a temperature sensor (33a-331, 36a-36c).

  The surplus liquid refrigerant amount calculation unit 3c detects the liquid surface position of the liquid storage container 24 by using the temperature data measured by the liquid surface detection sensors 36a to 36c and the pressure sensor, and stores the detected liquid surface position from the detected liquid surface position. The surplus liquid refrigerant amount in the liquid reservoir 24 is calculated based on the relational expression between the liquid surface position and the liquid amount stored in the part 3e.

  The determination unit 3d has a function of determining the presence or absence of refrigerant leakage based on the calculation result of the surplus liquid refrigerant amount calculation unit 3c. If the determination unit 3d further determines that there is refrigerant leakage, the determination unit 3d can also calculate the refrigerant leakage amount by taking the difference between the initial refrigerant amount and the calculated refrigerant amount.

  The storage unit 3e stores values measured by the measurement unit 3a, stores values calculated by the surplus liquid refrigerant amount calculation unit 3c, stores internal volume data and initial refrigerant amount described later, It has a function of storing information and storing a relational expression described later that is used when calculating the surplus liquid refrigerant amount.

  Based on the information measured by the measuring unit 3a and the like, the driving unit 3f drives each element (specifically, the compressor motor (compressor 21) and the valve mechanism (four-way valve 22, flow rate) of the refrigeration air conditioner 1). It has a function of controlling the regulating valves (open / close valve 28, open / close valve 29, expansion valve 41)), fan motor (outdoor fan 27, indoor fan 43), etc.

  The input unit 3g has a function of inputting and changing setting values for various controls. The input unit 3g may be configured by, for example, a remote controller that can be operated by a user or an operator, an operation panel, one of operation switches, or a combination thereof.

  The output unit 3h has a function of displaying a measurement value measured by the measurement unit 3a, a determination result by the determination unit 3d, and the like using an LED, a monitor, or the like, or outputting the result to the outside. The output unit 3h may function as a communication unit for communicating with an external device through a telephone line, a LAN line, wireless communication, or the like. In this way, the refrigerating and air-conditioning apparatus 1 can transmit refrigerant leakage presence / absence data indicating the refrigerant leakage determination result to a remote management center or the like via a communication line or the like. Accordingly, it is possible to add a remote monitoring function for always detecting an abnormality at a remote management center and performing maintenance immediately when the abnormality occurs.

  The measurement unit 3a and the surplus liquid refrigerant amount calculation unit 3c constitute the liquid level detection device of the present invention. Moreover, the refrigerant | coolant leakage detection apparatus of this invention is comprised by the measurement part 3a, the excess liquid refrigerant | coolant amount calculation part 3c, the determination part 3d, the memory | storage part 3e, and the output part 3h. In the present embodiment, the liquid level detection device and the refrigerant leakage detection device are incorporated in the refrigerating and air-conditioning apparatus 1. However, the present invention is not limited to this.

<Operation of Refrigeration Air Conditioner 1>
Next, the operation of each component during normal operation of the refrigeration air conditioner 1 will be described.
The refrigerating and air-conditioning apparatus 1 controls each component device of the outdoor unit 2 and the indoor units 4A and 4B according to the operation load of the indoor units 4A and 4B, and performs a cooling and heating operation.

(Cooling operation)
The cooling operation performed by the refrigerating and air-conditioning apparatus 1 will be described with reference to FIGS. 1 and 3. FIG. 3 is a ph diagram during the cooling operation of the refrigerating and air-conditioning apparatus 1. In FIG. 1, the flow of the refrigerant during the cooling operation is indicated by a solid arrow.

  During the cooling operation, the four-way valve 22 is in the state indicated by the solid line in FIG. 1, that is, the discharge side of the compressor 21 is connected to the gas side of the outdoor heat exchanger 23, and the suction side of the compressor 21 is connected to the on-off valve 29 and the gas. It is controlled to be connected to the gas side of the indoor heat exchangers 42A and 42B via the side extension pipe 7 (gas main pipe 7A, gas branch pipes 7a and 7b). Note that the on-off valve 28 and the on-off valve 29 are open. Moreover, FIG. 1 demonstrates as an example the case where air_conditionaing | cooling operation is performed by all the indoor units 4. FIG.

  The low-temperature and low-pressure refrigerant is compressed by the compressor 21 and discharged as a high-temperature and high-pressure gas refrigerant (point “A” shown in FIG. 3). The high-temperature and high-pressure gas refrigerant discharged from the compressor 21 flows into the outdoor heat exchanger 23 via the four-way valve 22. The refrigerant flowing into the outdoor heat exchanger 23 is condensed and liquefied while dissipating heat to the outdoor air by the blowing action of the outdoor fan 27 (point “C” shown in FIG. 3). The condensation temperature at this time is measured by the liquid side temperature sensor 33l or obtained by converting the pressure detected by the discharge pressure sensor 34b to a saturation temperature.

  Thereafter, the high-pressure liquid refrigerant that has flowed out of the outdoor heat exchanger 23 flows out of the outdoor unit 2 through the on-off valve 28. The pressure of the high-pressure liquid refrigerant that has flowed out of the outdoor unit 2 drops due to tube wall friction in the liquid main pipe 6A, the liquid branch pipe 6a, and the liquid branch pipe 6b (point “D” shown in FIG. 3). This refrigerant flows into the indoor units 4A and 4B and is decompressed by the expansion valves 41A and 41B to become a low-pressure gas-liquid two-phase refrigerant (point “E” shown in FIG. 3). The gas-liquid two-phase refrigerant flows into the indoor heat exchangers 42A and 42B functioning as a refrigerant evaporator, and is evaporated and gasified by absorbing heat from the air by the blowing action of the indoor fans 43A and 43B (shown in FIG. 3). Point “F”). At this time, the air-conditioning target area is cooled.

  The evaporation temperature at this time is measured by the liquid side temperature sensor 33e and the liquid side temperature sensor 33h. The superheat degree SH of the refrigerant at the outlets of the indoor heat exchangers 42A and 42B is determined by the liquid side temperature sensor 33e and the liquid side temperature sensor 33h from the refrigerant temperature values detected by the gas side temperature sensor 33f and the gas side temperature sensor 33i. It is obtained by subtracting the detected refrigerant temperature.

  Further, during the cooling operation, in the expansion valves 41A and 41B, the superheat degree SH of the refrigerant at the outlets of the indoor heat exchangers 42A and 41B (that is, the gas side of the indoor heat exchangers 42A and 42B) becomes the superheat degree target value SHm. The degree of opening is adjusted.

  The gas refrigerant (point “F” shown in FIG. 3) that has passed through the indoor heat exchangers 42A and 42B passes through the gas branch pipe 7a, the gas branch pipe 7b, and the gas main pipe 7A, which are the gas side extension pipes 7, and passes through the gas branch pipe. The pressure drops due to tube wall friction when passing through 7a, the gas branch pipe 7b, and the gas main pipe 7A (point “G” shown in FIG. 3). This refrigerant flows into the outdoor unit 2 through the on-off valve 29. The refrigerant flowing into the outdoor unit 2 is again sucked into the compressor 21 via the four-way valve 22 and the liquid reservoir 24. With the above flow, the refrigeration air conditioner 1 performs the cooling operation.

(Heating operation)
The heating operation performed by the refrigeration air conditioner 1 will be described with reference to FIGS. 1 and 4. FIG. 4 is a ph diagram during the heating operation of the refrigeration air conditioner 1. In addition, in FIG. 1, the flow of the refrigerant | coolant at the time of heating operation is represented by the broken-line arrow.

  During the heating operation, the four-way valve 22 is in the state indicated by the broken line in FIG. 1, that is, the discharge side of the compressor 21 is connected to the on-off valve 29 and the gas side extension pipe 7 (gas main pipe 7A, gas branch pipe 7a, gas branch pipe 7b). It is connected to the gas side of the indoor heat exchangers 42A and 42B, and the suction side of the compressor 21 is controlled to be connected to the gas side of the outdoor heat exchanger 23. Note that the on-off valve 28 and the on-off valve 29 are open. Moreover, FIG. 1 demonstrates as an example the case where heating operation is performed by all the indoor units 4. FIG.

  The low-temperature and low-pressure refrigerant is compressed by the compressor 21 and discharged as a high-temperature and high-pressure gas refrigerant (point “A” shown in FIG. 4). The high-temperature and high-pressure gas refrigerant discharged from the compressor 21 passes through the gas-side extension pipe 7 and flows out of the outdoor unit 2 through the four-way valve 22 and the on-off valve 29. The high-temperature and high-pressure gas refrigerant discharged from the compressor 21 drops in pressure due to tube wall friction when passing through the gas main pipe 7A, the gas branch pipe 7a, and the gas branch pipe 7b (point “B” shown in FIG. 4). ). This refrigerant flows into the indoor heat exchangers 42A and 42B of the indoor units 4A and 4B. The refrigerant that has flowed into the indoor heat exchangers 42A and 42B is condensed and liquefied while dissipating heat to the indoor air by the blowing action of the indoor fans 43A and 43B (point “C” shown in FIG. 4). At this time, heating of the air-conditioning target area is performed.

  The refrigerant flowing out of the indoor heat exchangers 42A and 42B is decompressed by the expansion valves 41A and 41B to become a low-pressure gas-liquid two-phase refrigerant (point “D” shown in FIG. 4). At this time, the opening degree of the expansion valves 41A and 41B is adjusted so that the supercooling degree SC of the refrigerant at the outlets of the indoor heat exchangers 42A and 42B becomes the supercooling degree target value SCm.

  The supercooling degree target value SCm is set large when the temperature difference between the room set temperature and the room temperature is small, and is set small when the temperature difference between the room set temperature and the room temperature is large. This is for adjusting the capacity of the indoor units 4A and 4B by changing the setting of the supercooling degree target value SCm. When the supercooling degree target value SCm is large, the expansion valves 41A and 41B operate in the direction to throttle in order to increase the supercooling degree SC, so that the refrigerant circulation amount is reduced and the capacity is not obtained. On the other hand, when the supercooling degree target value SCm is small, the expansion valves 41A and 41B operate in the direction of increasing the opening degree in order to reduce the supercooling degree SC. Since the exchangers 42A and 42B can be used effectively, the heat exchange capacity is increased.

  The degree of supercooling SC of the refrigerant at the outlets of the indoor heat exchangers 42A and 42B is obtained by converting the discharge pressure Pd of the compressor 21 detected by the discharge pressure sensor 34b into a saturation temperature value corresponding to the condensation temperature Tc. It is obtained by subtracting the refrigerant temperature value detected by the liquid side temperature sensors 33e and 33h from the saturation temperature value. A temperature sensor for detecting the temperature of the refrigerant flowing in the indoor heat exchangers 42A and 42B is separately provided, and the refrigerant temperature value corresponding to the condensation temperature Tc detected by the temperature sensor is set as the liquid side temperature sensor 33e, The subcooling degree SC of the refrigerant at the outlets of the indoor heat exchangers 42A and 42B may be obtained by subtracting from the refrigerant temperature value detected by the side temperature sensor 33h.

  Thereafter, the low-pressure gas-liquid two-phase refrigerant passes through the liquid main pipe 6A, the liquid branch pipe 6a, and the liquid branch pipe 6b, which are the liquid side extension pipes 6, and passes through the liquid main pipe 6A, the liquid branch pipe 6a, and the liquid branch pipe 6b. After the pressure drops due to the tube wall surface friction (point “E” shown in FIG. 4), it flows into the outdoor unit 2 through the on-off valve 28. The refrigerant that has flowed into the outdoor unit 2 flows into the outdoor heat exchanger 23, and is converted into evaporative gas by absorbing heat from the outdoor air by the blowing action of the outdoor fan 27 (point “F” shown in FIG. 4). Then, the refrigerant is sucked again into the compressor 21 through the four-way valve 22 and the liquid reservoir 24. With the above flow, the refrigeration air conditioner 1 performs the heating operation.

<Refrigerant amount of refrigeration air conditioner 1>
Next, the refrigerant amount of the refrigeration air conditioner 1 will be described in detail.
In order for each element device of the refrigerant circuit 10 of the refrigerating and air-conditioning apparatus 1 to exhibit a predetermined performance, an amount of refrigerant suitable for the inner volume of each element device is required. The inner volume of each of the indoor units 4A and 4B and the extension piping When the lengths of the refrigerant circuits are different, the refrigerant amount required for the entire refrigerant circuit 10 also varies. Therefore, after the refrigerant circuit 10 is configured at the site where the refrigeration air conditioner 1 is installed, the required amount of refrigerant is filled.

  Further, the required refrigerant amount in the refrigerant circuit 10 varies depending on the state of the refrigerant circuit 10. That is, the state of the refrigerant circuit 10 varies depending on the cooling and heating operation states, the ambient environment such as the outside air temperature and the room temperature, and the necessary amount of refrigerant in the refrigerant circuit 10 varies accordingly. For this reason, normally, when filling the refrigerant, the refrigerant is filled in accordance with an operation state that requires a large amount of refrigerant. Therefore, the surplus liquid refrigerant is stored in the liquid storage container 24 in an operation state that does not require a large amount of refrigerant.

  The refrigerant circuit 10 requires a larger amount of refrigerant in the cooling operation than in the heating operation. This is because the expansion valves 41A, 41B are provided on the indoor units 4A, 4B side, so that the refrigerant state of the extension pipe is the liquid phase extension pipe 6 in the liquid phase and the gas side extension pipe 7 in the gas phase during the cooling operation. In contrast, during the heating operation, the liquid-side extension pipe 6 has a two-phase and the gas-side extension pipe 7 has a gas phase. In other words, in the liquid side extension pipe 6, the liquid phase state is in the cooling operation, the two phase state is in the heating operation, and the liquid phase state requires more refrigerant due to the difference between the liquid phase state and the two phase state. For this reason, a larger amount of refrigerant is required during the cooling operation.

  Further, the difference in internal volume between the condenser and the evaporator and the difference in density between the condensation density and the evaporation density also greatly affect the required refrigerant amount. Usually, the internal volume of the outdoor heat exchanger 23 is larger than that of the indoor heat exchangers 42A and 42B, and the average density of the condenser is larger than that of the evaporator. Therefore, during the cooling operation, the outdoor heat exchanger 23 side having a large internal volume becomes a condenser having a large average density, so that a larger amount of refrigerant is required than during the heating operation.

  From the above, when the cooling operation or the heating operation is performed by switching the four-way valve 22, the refrigerant amount required for the cooling operation and the heating operation is different. In such a case, the refrigerant is charged in accordance with the operation state that requires a large amount of refrigerant, and in the operation state that does not require a large amount of refrigerant, the excess liquid refrigerant is stored in the liquid storage container 24 or the like. .

[Description of phenomenon in which refrigerant is stored in low-pressure liquid reservoir 24]
A phenomenon in which the refrigerant accumulates in a low-pressure liquid storage container after a predetermined time has elapsed since the refrigerating and air-conditioning apparatus 1 is stopped will be described by taking a cooling operation as an example. The state of change of the refrigerant amount of each element after the refrigeration air conditioner 1 is stopped is shown in FIGS. 5-9, the case where the normal quantity of refrigerant | coolant is enclosed (line a1-line a5) and the case where it is less than 30% normal quantity (line b1-line b5) are shown collectively.

  FIG. 5 is a diagram showing time-lapse data of the refrigerant amount in the liquid storage container 24 when the compressor 21 is stopped for a predetermined time. FIG. 6 is a diagram showing time-lapse data of the refrigerant amount of the outdoor heat exchanger 23 when the compressor 21 is stopped for a certain predetermined time. FIG. 7 is a diagram showing time-lapse data of the refrigerant amount in the liquid pipe when the compressor 21 is stopped at a predetermined time. FIG. 8 is a diagram showing time-lapse data of the refrigerant amount in the gas pipe when the compressor 21 is stopped at a certain predetermined time. FIG. 9 is a diagram showing time-lapse data of the refrigerant amount in the indoor heat exchanger 42 when the compressor 21 is stopped for a predetermined time.

  Before the compressor 21 is stopped (for example, 10 seconds before), a large amount of liquid refrigerant exists in the indoor heat exchangers 42A and 42B and the liquid side extension pipe 6, and the liquid reservoir 24 and the gas side extension pipe 7 The amount of refrigerant is small.

  After the compressor 21 is stopped, the liquid refrigerant on the high pressure side rapidly moves to the low pressure side. First, the amount of refrigerant in the indoor heat exchangers 42A and 42B increases, and the amount of refrigerant in the gas side extension pipe 7 increases slightly after a delay.

  The amount of refrigerant in the indoor heat exchangers 42 </ b> A and 42 </ b> B and the gas side extension pipe 7 once increases, but immediately starts to decrease, and finally the liquid refrigerant concentrates in the liquid reservoir 24.

  From the above, it can be seen that the liquid refrigerant on the high pressure side passes through the indoor heat exchangers 42 </ b> A and 42 </ b> B and the gas side extension pipe 7 and accumulates in the liquid reservoir 24. During operation, when the amount of the enclosed refrigerant is insufficient, the liquid side extension pipe 6 is in a two-phase state, and the difference in the refrigerant amount of the liquid side extension pipe 6 is larger than when the normal amount is sealed. It is getting bigger. In contrast, it can be seen that there is almost no difference in the refrigerant amount on the low pressure side.

  The behavior of the refrigeration and air-conditioning apparatus 1 after the stop is not affected by the difference in the amount of the enclosed refrigerant, and only the liquid reservoir 24 has a difference in the amount of the refrigerant when the refrigerant becomes stable after the stop. Therefore, if the amount of liquid refrigerant in the liquid storage container 24 can be detected when a predetermined time has elapsed after the refrigeration air conditioner 1 is stopped, a change in the amount of the enclosed refrigerant, that is, the presence or absence of refrigerant leakage is detected. can do.

(Influence of outside temperature)
FIG. 10 shows changes in the refrigerant amount in the liquid storage container 24 when the outside air temperature is changed in three ways, and FIG. 11 shows changes in the refrigerant amount in the outdoor heat exchanger 23, respectively. In FIGS. 10 and 11, the liquid storage container when the outside air temperature is changed to 22 ° C. (line c1, line c2), 27 ° C. (line d1, line d2), and 32 ° C. (line e1, line e2). 24, changes in the refrigerant amount of the outdoor heat exchanger 23 are shown.

  When the outside air temperature is higher than the room temperature, the amount of refrigerant accumulated in the outdoor heat exchanger 23 decreases, and the amount accumulated in the liquid reservoir 24 slightly increases (about 3%).

  From this, it is possible to detect the change in the amount of the enclosed refrigerant with high accuracy by taking into consideration the temperature difference between the outside air temperature and the room temperature.

(Effect of height difference)
The installation position of the indoor unit 4 was changed by ± 30 m with respect to the outdoor unit 2, and the influence of the pressure head of the liquid side extension pipe 6 was examined. FIG. 12 shows changes in the refrigerant amount in the liquid storage container 24, and FIG. 13 shows changes in the refrigerant amount in the outdoor heat exchanger 23. In FIGS. 12 and 13, when the height difference between the indoor unit 4 and the outdoor unit 2 is 0 m (line f1, line f2), +30 m (line g1, line g2), and −30 m (line h1) , Line h2), the change in the refrigerant amount of the liquid reservoir 24 and the outdoor heat exchanger 23 is shown.

  Even if the liquid pipe head is changed, there is no change in the amount of the refrigerant that is stable after the refrigerating and air-conditioning apparatus 1 is stopped. From this, it can be seen that the amount of refrigerant in the liquid reservoir 24 in a stable state after the refrigerating and air-conditioning apparatus 1 is stopped does not depend on installation conditions.

  A method for detecting the liquid level by measuring the surface temperature of the liquid reservoir 24 after the refrigerating and air-conditioning apparatus 1 is stopped will be described.

  When the refrigeration air conditioner 1 is filled with azeotropic refrigerant or pseudo azeotropic refrigerant as the refrigerant, the temperature of the gas-liquid inside the liquid storage container 24 is equal, and a temperature sensor is simply installed in the liquid storage container 24. However, the gas-liquid cannot be determined. However, after the refrigerating and air-conditioning apparatus 1 is stopped, the pressure of the liquid storage container 24 changes suddenly and the temperature of the gas part follows the pressure fluctuation, whereas the liquid part has a heat capacity. Will be delayed with respect to the pressure fluctuation, and a temperature difference will occur in the gas-liquid part. However, since the heat capacity is limited even in the liquid part, the temperature of the gas part and the liquid part become equal after 30 minutes or more after the refrigerating and air-conditioning apparatus 1 is stopped, and the temperature difference is eliminated.

  Even when the refrigerant circuit 10 is filled with non-azeotropic refrigerant, if the saturated gas temperature and the saturated liquid temperature are close to each other, there is a possibility of erroneous detection because the temperature difference between the gas and liquid is small. Therefore, according to the refrigerating and air-conditioning apparatus 1, since a temperature difference between the gas phase portion and the liquid phase portion can be generated, even if a non-azeotropic refrigerant is used, the gas-liquid at the position where the temperature sensor is installed is effective. Can be determined.

  A plurality of temperature sensors (for example, three temperature sensors (liquid level detection sensors 36a to 36c) as shown in FIG. 1)) may be installed in the vertical direction of the liquid reservoir 24 so that the gas and liquid can be determined. . By doing in this way, in the refrigeration air conditioner 1, the liquid level position inside the liquid reservoir 24 can be specified, and the amount of liquid refrigerant stored in the liquid reservoir 24 (hereinafter referred to as surplus liquid refrigerant amount). It can be converted. That is, a plurality of temperature sensors function as sensor units of a liquid level detection device installed in the liquid reservoir 24. The conversion process of the excess liquid refrigerant amount will be described in detail later.

  In FIG. 1, the configuration of the sensor unit of the liquid level detection device installed in the liquid reservoir 24 is the simplest configuration in which only the temperature sensor is attached, but is not limited thereto. For example, a heat insulating material is installed outside the temperature sensor to eliminate the influence from the outside as much as possible, or the surface temperature of the liquid storage container 24 is surely transmitted to the temperature sensor between the liquid storage container 24 and the temperature sensor. It is good also as a structure which installed the heat conductive sheet. The material of the heat insulating material used at this time may be a foam heat insulating material typified by polystyrene foam, phenol foam or urethane foam, or a fiber heat insulating material typified by glass wool. In addition, the heat conductive sheet is not limited to a heat conductive metal sheet such as silicone, copper, aluminum, etc., or a soaking sheet, and heat conduction grease may be used to prevent air layer formation. Good.

<Gas-liquid discrimination principle>
Next, the principle for discriminating the gas-liquid of the refrigerant will be described by taking as an example the case where the compressor 21 is stopped. First, the determination of the liquid level position inside the liquid reservoir 24 will be described based on FIG. 14, and then the gas-liquid determination method will be described based on FIG. 15 and FIG.

  Changes in pressure and temperature inside the liquid storage container 24 when the compressor 21 is stopped will be described with reference to FIG. 14 which is test data. FIG. 14 shows time lapse data of the frequency of the compressor 21 when the compressor 21 is stopped at a predetermined time A, the low pressure inside the liquid reservoir 24, the saturation temperature, the gas phase temperature, and the liquid phase temperature. FIG. In addition, the horizontal axis of FIG. 14 has shown time.

As shown in FIG. 1, the liquid reservoir 24 is installed on the suction side of the compressor 21. Since the liquid storage container 24 is connected to the low pressure side, the internal pressure of the liquid storage container 24 shows a low value until the compressor 21 is stopped. This is a state where a gas phase is present at the top, that is, a two-phase state.
As the refrigerant of the refrigerating and air-conditioning apparatus 1, for example, when an azeotropic refrigerant having the same saturated gas temperature and the saturated liquid temperature or a pseudo-azeotropic refrigerant having the same saturated gas temperature and the saturated liquid temperature is used, the temperature difference in the gas-liquid section is It can be seen that it is difficult to discriminate between gas and liquid in the two-phase state where there is no gas.
In addition, even when the refrigerant circuit 10 is filled with non-azeotropic refrigerant, it can be seen that there is a possibility of erroneous detection because the temperature difference between the gas and liquid is small when the saturated gas temperature and the saturated liquid temperature are close.

  When the compressor 21 is stopped at a predetermined time A, the pressure difference between the high and low pressures in the liquid storage container 24 is eliminated, the pressure is equalized, the internal pressure of the liquid storage container 24 rises as shown by the line x1, and the refrigerant The saturation temperature also increases as shown by line x2. At this time, if the inside of the liquid reservoir 24 is a gas phase, the line x3 changes to be equal to the saturation temperature line x2. On the other hand, if the inside of the liquid reservoir 24 is a liquid phase, the line x4 is as shown in FIG. Gradually approach the saturation temperature (dotted line x2).

  From the above, it can be seen that the surface temperature of the liquid storage container 24 after the compressor 21 is stopped varies depending on the internal state of the liquid storage container 24, that is, the gas phase or the liquid phase. Therefore, by measuring the surface temperature of the liquid reservoir 24, the liquid level position inside the liquid reservoir 24 can be determined.

(Gas-liquid discrimination method)
Next, taking the case where the compressor 21 is stopped as an example, the gas-liquid discrimination method will be described with reference to FIG. FIG. 15 shows that the compressor 21 is stopped at a certain predetermined time A, and the frequency of the compressor 21 when the predetermined time has elapsed and the low pressure inside the reservoir 24, the saturation temperature, the gas phase temperature, the liquid It is the figure which showed the time passage data of phase temperature. FIG. 16 is obtained by adding the outside air temperature to the data shown in FIG. In addition, the horizontal axis of FIG.15 and FIG.16 has shown time.

  As a gas-liquid discrimination method, there is a method for making a gas-liquid discrimination from temperature data when a predetermined time has elapsed after the change of the component device. In this method, after the compressor 21 as the component device is stopped, the temperature of the liquid storage container 24 is measured after a predetermined time (for example, 5 minutes) has elapsed, and the saturation temperature of the low-pressure pressure is used as a threshold value. It is a method of discrimination.

Basically, the gas part (gas phase part) has the same temperature as the saturated gas temperature, but taking into account the heat conduction of the container, sensor error, etc., the gas-liquid judgment is given a width α, Perform gas-liquid discrimination.
｜ Threshold-measured value | <α → Gas part ｜ Threshold-measured value |> α → Liquid part (liquid phase part)

  Here, the reason for setting the predetermined time to 5 minutes, for example, is 5 minutes until the pressure stabilizes (that is, until the time A ′ shown in FIG. 15) after changing the element equipment during the test. This is because it takes about a certain amount of time, and it is easy to determine the gas-liquid temperature difference by setting the predetermined time to about 5 minutes. Naturally, this time varies depending on the equipment configuration and operating conditions of the refrigerating and air-conditioning apparatus 1. For this reason, it is necessary to set a time during which gas-liquid discrimination is easy for each condition, taking them into account. The predetermined time may be set to 1 minute or more and 30 minutes or less, and the predetermined time may be set according to the condition within this range.

  As described above, the case where the gas-liquid is determined from the temperature difference from the saturated gas temperature is taken as an example, but the present invention is not limited to this. By using the characteristic that the gas part is equal to the saturation temperature, when the liquid surface position can be specified, that is, when the temperature is equal at a plurality of measurement points, the measurement part can be determined as the gas part. Further, if the temperature is different at a plurality of measurement points, the measurement point can be determined as a liquid part. In this way, the gas and liquid may be discriminated by using the characteristic that the gas portion is equal to the saturation temperature. However, at this time, since the liquid storage container 24 is a metal having good heat transfer, it is necessary to determine the gas and liquid in consideration of heat transfer in the container portion of the liquid storage container 24.

  In addition, although the method for determining the gas and liquid from the temperature data when the predetermined time has elapsed has been described, the present invention is not limited to this. For example, the gas and liquid may be determined using the temperature as a threshold value. For example, as shown in FIG. 16, when the refrigerating and air-conditioning apparatus 1 is stopped, it is conceivable that the saturation temperature of the liquid reservoir 24 gradually approaches the outside air temperature. Moreover, the temperature difference in the gas-liquid part tends to increase at the part where the saturation temperature becomes the outside air temperature. From this, by using the saturation temperature as a trigger and performing gas-liquid discrimination at time A ′ when the saturation temperature becomes the outside air temperature (line y), it becomes possible to perform gas-liquid discrimination in a state where the temperature difference in the gas-liquid section is large. Become. In this way, it is possible to perform gas-liquid discrimination at a portion where the temperature difference between the gas and liquid is large without setting a predetermined time.

  In addition, the measured values up to a predetermined time after the element device is changed may be integrated, and the gas-liquid determination may be made based on the difference between the integrated values.

(Liquid level discrimination method)
As described above, since the surface temperature of the liquid storage container 24 is measured by changing the internal pressure or temperature of the liquid storage container 24, the installation height of the temperature sensor is in the gas phase or in the liquid phase. It is possible to determine whether it exists. Therefore, according to the refrigerating and air-conditioning apparatus 1, the liquid level position of the liquid reservoir 24 is detected by installing a plurality of temperature sensors (liquid level detection sensors 36 a to 36 c) in the vertical direction on the side surface of the liquid reservoir 24. It becomes possible.

(Flow of refrigerant leak detection)
Next, the flow of the refrigerant leakage detection method in the refrigeration air conditioner 1 will be described. The refrigerant leakage detection is always performed while the refrigeration air conditioner 1 is in operation. The refrigerating and air-conditioning apparatus 1 is configured to be capable of remote monitoring by transmitting refrigerant leakage presence / absence data indicating the detection result of refrigerant leakage to a management center (not shown) or the like via a communication line.

  The refrigerating and air-conditioning apparatus 1 detects the refrigerant leakage in the liquid storage container 24 after it is stopped by detecting the refrigerant amount in the liquid level detection sensors 36a to 36c and monitoring changes in the refrigerant amount. Hereinafter, the refrigerant leak detection method executed by the refrigeration air conditioner 1 will be described with reference to FIG. Here, FIG. 17 is a flowchart showing the flow of the refrigerant leakage detection process in the refrigeration air conditioner 1. The refrigerant leakage detection is performed after a predetermined time has elapsed since the refrigeration air-conditioning apparatus 1 is stopped (5 minutes in the figure).

  First, the control unit 3 determines whether a predetermined time has elapsed since the refrigerating and air-conditioning apparatus 1 was stopped (step S001). When it is not stopped or when a predetermined time has not elapsed, refrigerant leakage detection is not performed.

  Next, the controller 3 measures the amount of refrigerant inside the liquid reservoir 24 (step S002). The flow of calculating the surplus liquid refrigerant amount will be described later with reference to FIG.

  Next, the control unit 3 calculates a predetermined reference value (initial refrigerant amount) measured in advance and the measured value, and compares them (step S003). At this time, if the measured value (calculated refrigerant amount) is less than the predetermined reference value, the process proceeds to step S004, and if the measured value is equal to the predetermined reference value, the process proceeds to step S005.

  Next, in step S004, since it is determined that the total refrigerant amount is smaller than the initial refrigerant amount in step S003, the control unit 3 determines that the refrigerant is leaking and issues a refrigerant leak notification.

  On the other hand, in Step S005, since it is determined in Step S003 that the total refrigerant amount is equal to the initial refrigerant amount, the control unit 3 determines that the refrigerant is not leaking and notifies that the refrigerant is normal.

(Flow of calculation of surplus liquid refrigerant amount)
Next, the flow of calculating the amount of liquid refrigerant in the liquid reservoir in step S002 of FIG. 17 will be described with reference to FIG. FIG. 18 is a flowchart showing the flow of calculation of the amount of liquid refrigerant in the liquid reservoir in step S002 of FIG. 17 of the refrigerant leakage detection process in the refrigeration air conditioner 1.

  First, in step S201, the control unit 3 confirms that the compressor 21 is stopped.

  Next, in step S202, the control unit 3 determines whether a predetermined time has elapsed. When the predetermined time has elapsed, the process proceeds to step S203, and the pressure is measured. In the present embodiment, since the liquid reservoir 24 is installed on the low pressure side, the low pressure is measured.

  In step S204, the control unit 3 calculates a saturation temperature from the pressure measured in step S203, and stores it in the storage unit 3e as a threshold value. Thereafter, the control unit 3 measures the surface temperature of the liquid storage container 24 based on information from the liquid level detection sensors 36a to 36c installed on the surface of the liquid storage container 24 (steps S205 to S208).

  First, in step S205, the control unit 3 sets n = 1.

  In step S206, the control unit 3 determines the surface temperature of the liquid reservoir 24 at the installation position of the liquid level detection sensor based on information from the nth liquid level detection sensor (for example, the liquid level detection sensor 36a). Measure and memorize.

  In step S207, the control unit 3 determines whether n = the number of sensors.

  If n is not the number of sensors, in step S208, the control unit 3 adds 1 to n and executes the process of step S206 again.

  When the controller 3 measures and stores the surface temperature of the liquid reservoir 24 based on information from all the liquid level detection sensors (step S207; Yes), n = 1 is set again in step S209.

Steps S <b> 210 to S <b> 218 indicate a flow for specifying the liquid surface position.
In step S210, the control unit 3 calculates a difference from the saturation temperature that is a threshold, and determines whether or not the absolute value of the difference is within α. That is, in step S210, the control unit 3 performs gas-liquid discrimination.

  If the difference is larger than α, it can be determined that the liquid portion has a large temperature difference from the saturation temperature. Therefore, the control unit 3 proceeds to step S211 and sets m as the sensor number that has passed step S210 (S211), and the next liquid Move to surface detection sensor. When there is a liquid level detection sensor in the liquid part of the liquid storage container 24, the control unit 3 repeats Steps S210 to S213, and stores the sensor number having the highest position in the liquid part as m (Step S218).

  If the difference is within α, it is determined to be a gas part because it is substantially equal to the saturation temperature, and the control unit 3 proceeds to step S214. Once it is determined in step S210 that it is a gas part, it is impossible to determine that it is a liquid part thereafter in accordance with the gas-liquid discrimination principle in the present embodiment unless a sensor malfunction occurs. Therefore, after adding 1 to n at step S215, the control unit 3 proceeds to the determination at step S216. If it is determined in step S216 that it is a liquid part (when greater than α), the control unit 3 proceeds to step S217 and reports that the liquid level cannot be detected and the surplus liquid refrigerant amount cannot be calculated.

  On the other hand, when it is determined in step S216 that it is a gas part (when it is within α), the control unit 3 maintains the measurement of the gas part among the liquid level detection sensors determined to be the gas part. Steps S214 to S216 are repeated until the detected liquid level detection sensor is obtained.

  As mentioned above, the control part 3 can clarify the sensor number m in the highest position in a liquid part by the flow of step S210-step S218.

  Next, in step S219, the control unit 3 calculates the surplus liquid refrigerant volume in the liquid reservoir 24 from the sensor number determined to be at the highest position in the liquid part. The surplus liquid refrigerant volume is calculated from the relationship between the sensor number stored in the storage unit 3e in advance and the surplus liquid refrigerant volume.

  Next, in step S <b> 220, the control unit 3 calculates a saturated gas density and a saturated liquid density from the pressure inside the liquid storage container 24.

  Next, in step S221, the controller 3 determines the amount of liquid refrigerant in the liquid storage container 24 from the surplus liquid refrigerant volume calculated in steps S219 and S220, the saturated gas density of the liquid storage container 24, and the saturated liquid density. Is calculated.

  The above description has been made on the assumption that the relationship between the position of the liquid level detection sensor 36a to the liquid level detection sensor 36c installed on the surface of the liquid storage container 24 and the liquid amount is known, but the present invention is not limited to this. . For example, when a temperature sensor is retrofitted to an existing refrigeration air conditioner, the relationship between the position of the temperature sensor and the amount of liquid is unknown. In such a case, after installing the temperature sensor, the relationship between the number of the temperature sensor at the highest position in the liquid part and the liquid volume is detected under a plurality of conditions in which a plurality of surplus liquid refrigerant amounts change, and as a database By adding the initial learning step to be stored, the excess liquid refrigerant amount can be detected.

  As described above, the refrigerating and air-conditioning apparatus 1 specifies the liquid surface position by measuring this temperature on the surface of the liquid storage container 24 when the temperature is different between the gas phase portion and the liquid phase portion. Yes. By doing so, according to the refrigeration air conditioner 1, the liquid level detection sensor can have a simple configuration with only a temperature sensor, and there are advantageous effects of low cost, reduced measurement value variation, and easy sensor installation.

<Detection accuracy improvement method>
Next, a method for improving the refrigerant leak detection accuracy will be described.

  In order to improve the accuracy of refrigerant leakage detection, it is desirable that the amount stored in the liquid storage container 24 be a constant amount at a predetermined timing for measuring the liquid storage amount regardless of the environmental state. To achieve this, the refrigeration cycle state before stopping should be made equal, the state of each elemental device at the time of stopping should be made equal, and when the operating state changes greatly, such as cooling / heating, it is determined in each operating state. It is necessary to set a reference value for this, and to measure the amount of liquid reservoir at an appropriate timing.

  A specific method is shown below. First, a method for equalizing the refrigeration cycle state before stopping will be described. The driving force necessary for the refrigerant to move after the stop is a high-low pressure difference before the stop of the refrigeration cycle (refrigerant circuit 10). If the difference between the high and low pressures before the stop is small, the liquid refrigerant cannot move to the liquid storage container 24 and remains in the heat exchanger or piping on the way. Since the presence or absence of refrigerant leakage is detected by the amount of liquid in the liquid reservoir 24, if the refrigerant stays on the way, it is not possible to accurately determine the refrigerant leakage. From the above, it is necessary to set the height difference before the refrigeration cycle is stopped to a predetermined value or more. The required height difference of the refrigeration cycle differs depending on the installation environment and the piping length of the outdoor unit 2 and the indoor unit 4, but if the high / low pressure difference of the refrigeration cycle is 1 MPa or more, the height difference between the outdoor unit 2 and the indoor unit 4 Even if there is about 10 m, it is confirmed that the liquid refrigerant returns to the liquid reservoir 24 after the stop.

  Furthermore, in order to improve the refrigerant leakage detection accuracy, it is desirable to set the high / low pressure difference of the refrigeration cycle before the stop to a constant value. By controlling the compressor 21, the outdoor fan 27, and the expansion valve 41 to change the operating state of the refrigeration cycle before stopping even if environmental conditions change, such as when the outside air temperature changes, the liquid in the liquid reservoir 24 Variation in refrigerant quantity is reduced. Therefore, by doing so, erroneous detection can be reduced and detection accuracy can be improved.

  Next, a method for improving the accuracy of refrigerant leakage detection by equalizing the state of each component device at the time of stopping will be described. After the compressor 21 is stopped, the component devices that affect the movement of the refrigerant are valves such as an expansion valve 41 and an electromagnetic valve (open / close valve 28, open / close valve 29). If the opening of the valve is large, the refrigerant moves easily. On the other hand, if the opening of the valve is small, the movement of the refrigerant is hindered, the refrigerant does not move easily, the driving force is weakened, and the refrigerant is stored in a heat exchanger or piping. For this reason, if the opening state of the valve after the stop is different, the amount stored in the liquid storage container 24 is different. From the above, by making the opening state of the valve at the time of stop equal (fixed to a constant value) and equalizing the pressure loss, the variation in the amount of liquid refrigerant in the liquid reservoir 24 is reduced, thereby reducing false detection. Detection accuracy can be improved.

  Furthermore, in order to improve the refrigerant leakage detection accuracy, the valve opening after the compressor 21 is stopped is set to a larger opening than that during operation (the best method is fully open). By reducing the opening of the valve to a larger opening than during operation, or by fully opening the valve, it is possible to suppress a decrease in driving force, thereby reducing variations in the amount of liquid refrigerant in the liquid storage container 24 and causing false detection. And detection accuracy can be improved. Note that “fully open” is not limited to strict “fully open”, and “fully opened” includes an opening close to fully open (an opening in the vicinity of fully open).

  On the contrary, when the opening degree of the valve is smaller than a predetermined value, the refrigerant amount of each element device other than the liquid reservoir container 24 before the stop and the refrigerant amount of the liquid reservoir container 24 after the stop are calculated, The refrigerant amount of the entire system (entire refrigerant circuit 10) is calculated in total and compared with a predetermined reference value to detect refrigerant leakage. This is because when the opening degree of the valve is smaller than a predetermined value, the driving force for moving the refrigerant is small, and the refrigerant amount distribution of each element after stopping depends on the refrigerant distribution during operation. Thus, when the opening degree of the valve is smaller than a predetermined value, even if the amount of refrigerant in the liquid storage container 24 after stopping is estimated as described above, erroneous detection and detection accuracy deteriorate. From the above, the refrigerant amount of each operating element device is calculated from the pressure and temperature data, the refrigerant amount in the liquid reservoir 24 after the stop is calculated from the liquid level detection sensor 36, and these are totaled. The refrigerant leakage is detected by calculating the refrigerant quantity and comparing it with a predetermined reference value.

  In the present embodiment, the refrigerant flow differs between the cooling operation and the heating operation. When the flow varies depending on the operating state as described above, the location and amount of the refrigerant stored in the heat exchanger, piping, and the like are different. Therefore, by giving a predetermined reference value separately in each operation state, it is possible to determine refrigerant leakage in consideration of the amount accumulated in elements other than the liquid reservoir 24, thereby reducing false detection. Detection accuracy can be improved.

  When the refrigerant leakage is detected by measuring the amount of liquid refrigerant in the liquid storage container 24 after the stop, there is an appropriate time for improving the detection accuracy. If the timing of measuring the amount of liquid refrigerant is early, the amount of liquid is measured before the refrigerant moves from each element to the liquid reservoir 24, resulting in large variations. Conversely, if the timing for measuring the amount of liquid refrigerant is late, the amount stored in the heat exchanger or piping changes due to the influence of the outside air temperature, and the variation in the amount of refrigerant in the liquid reservoir 24 increases.

  Although the appropriate detection timing varies depending on the installation status of the equipment such as the length of the piping, the installation position of the outdoor unit 2 and the indoor unit 4 and the operation status, the amount of liquid in the liquid storage container 24 can be adjusted within a range of 1 to 30 minutes after stopping. By measuring, variation in the amount of liquid refrigerant in the liquid reservoir 24 can be suppressed, and detection errors can be reduced and detection accuracy can be improved.

  Further, according to the refrigeration air conditioner 1, the amount of refrigerant leakage can be calculated by comparing the amount of liquid refrigerant stored in the liquid reservoir 24 with the initial value. The work process and the like can be detected, improving the maintenance work efficiency.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments and can be changed without departing from the scope of the invention.

  For example, in the present embodiment, the building multi-air conditioner has been described as shown in FIG. 1, but the present invention is not limited to this. For example, the present invention can also be applied to a refrigerating and air-conditioning apparatus such as a refrigerator that does not have a four-way valve 22 and that has a liquid storage container installed at the outlet of an outdoor heat exchanger in a high-pressure section. That is, it is possible to detect excess liquid refrigerant in the high-pressure side liquid reservoir and to detect refrigerant leakage.

  Further, the expansion valves 41A and 41B are installed in the indoor units 4A and 4B. However, the present invention is not limited to this, and the expansion valves 41A and 41B may be installed in the outdoor unit 2. In either case, the present invention can be applied.

  By constructing the above connection configuration and transmitting detection data on the presence or absence of refrigerant leakage to a management center or the like, refrigerant leakage detection can always be performed remotely. Therefore, it is possible to cope with sudden refrigerant leakage immediately before an abnormality such as damage to the equipment or a decrease in capability occurs, and it is possible to suppress the progression of refrigerant leakage as much as possible. Thereby, the reliability of the refrigerating and air-conditioning apparatus 1 can also be improved, and deterioration of the environmental state due to the outflow of the refrigerant can be prevented as much as possible.

  Furthermore, since it is possible to avoid the inconvenience of excessive operation with a small amount of refrigerant due to refrigerant leakage, the life of the refrigeration air conditioner 1 can be extended. When there is refrigerant leakage, the determination unit 3d may calculate the refrigerant leakage amount, and notify the outside of the management center or the like from the output unit 3h together with the determination result.

  In the above-described embodiment, the case where the presence or absence of refrigerant leakage is determined has been described. However, the present invention can also be applied to the determination of whether or not the amount of the refrigerant is excessive when the refrigerant is charged.

  In the above-described embodiment, the refrigeration and air-conditioning apparatus 1 including one outdoor unit 2 and two indoor units 4 is taken as an example. However, the present invention is not limited thereto, and one outdoor unit 2 and 1 The refrigerating and air-conditioning apparatus 1 including a plurality of indoor units 4 or the refrigerating and air-conditioning apparatus 1 including a plurality of outdoor units 2 and a plurality of indoor units 4 may be used.

  DESCRIPTION OF SYMBOLS 1 Refrigeration air conditioning apparatus, 2 outdoor unit, 3 control part, 3a measurement part, 3c surplus liquid refrigerant | coolant amount calculation part, 3d determination part, 3e memory | storage part, 3f drive part, 3g input part, 3h output part, 4 indoor unit, 4A Indoor unit, 4B Indoor unit, 6 liquid side extension pipe, 6A liquid main pipe, 6a liquid branch pipe, 6b liquid branch pipe, 7 gas side extension pipe, 7A gas main pipe, 7a gas branch pipe, 7b gas branch pipe, 10 refrigerant circuit 10a indoor refrigerant circuit, 10b indoor refrigerant circuit, 10c outdoor refrigerant circuit, 21 compressor, 22 four-way valve, 23 outdoor heat exchanger, 24 liquid reservoir, 27 outdoor fan, 28 open / close valve, 29 open / close valve, 31 outdoor side control unit, 32 indoor side control unit, 32a indoor side control unit, 32b indoor side control unit, 33a suction temperature sensor, 33b discharge temperature sensor, 33c outdoor temperature 33e Liquid side temperature sensor, 33f Gas side temperature sensor, 33g Indoor temperature sensor, 33h Liquid side temperature sensor, 33i Gas side temperature sensor, 33j Indoor temperature sensor, 33k Heat exchange temperature sensor, 33l Liquid side temperature sensor, 34a Inhalation Pressure sensor, 34b Discharge pressure sensor, 36 Liquid level detection sensor, 36a Liquid level detection sensor, 36b Liquid level detection sensor, 36c Liquid level detection sensor, 41 Expansion valve, 41A Expansion valve, 41B Expansion valve, 42 Indoor heat exchanger, 42A indoor heat exchanger, 42B indoor heat exchanger, 43 indoor fan, 43A indoor fan, 43B indoor fan, 51a distributor, 52a distributor.

Claims (9)

A refrigeration cycle apparatus having a refrigerant circuit in which a compressor, a condenser, an expansion valve, an evaporator and a liquid storage container are connected by piping,
A liquid level detection sensor for detecting the amount of liquid refrigerant in the liquid reservoir;
When a predetermined amount of time has elapsed since the compressor stopped, the liquid level in the liquid storage container is detected by the liquid level detection sensor, and when the opening of the expansion valve is smaller than a predetermined value, The refrigerant amount of the entire refrigerant circuit is calculated from the refrigerant amount of each element device other than the liquid reservoir before the compressor is stopped and the refrigerant amount of the liquid reservoir after the compressor is stopped. A refrigeration cycle apparatus comprising: a refrigerant leak detection device that determines whether or not refrigerant leaks from the refrigerant circuit by comparing with a predetermined reference value. When the opening of the expansion valve is smaller than a predetermined value,
Driving force for the coolant transfer is smaller than during the operation of the compressor, according to claim 1 refrigerant quantity distribution after stop of the compressor is depend on the refrigerant distribution in the operation of the compressor Refrigeration cycle equipment. The opening of the expansion valve after the compressor is stopped,
The refrigeration cycle apparatus according to claim 1 or 2 , wherein the refrigeration cycle apparatus is fixed to a constant value. The predetermined time is
The refrigeration cycle apparatus according to any one of claims 1 to 3 , wherein the refrigeration cycle apparatus is set for a time within a range of 1 minute to 30 minutes. The refrigeration cycle apparatus according to any one of claims 1 to 4 , wherein a pressure difference between the high pressure and the low pressure of the refrigerant circuit before the compressor is stopped is 1 MPa or more. The liquid level detection sensor comprises a temperature sensor,
The refrigeration cycle apparatus according to any one of claims 1 to 5 , wherein an amount of liquid refrigerant in the liquid storage container is detected by measuring a surface temperature of the liquid storage container. A refrigerant leakage detection device that detects refrigerant leakage from a refrigerant circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a liquid storage container are pipe-connected,
A measurement unit that detects the amount of liquid refrigerant in the liquid storage container and measures an operation state amount of the refrigerant circulating in the refrigerant circuit based on the amount of liquid refrigerant;
An excess liquid refrigerant amount calculating unit that calculates an amount of excess liquid refrigerant in the liquid storage container based on information from the measurement unit;
When the opening degree of the expansion valve is smaller than a predetermined value, the refrigerant amount of each element device other than the liquid reservoir container before the compressor stops, and when a predetermined time has elapsed since the compressor stopped A determination unit that calculates the refrigerant amount of the entire refrigerant circuit from the calculation result of the surplus liquid refrigerant amount calculation unit, and determines the presence or absence of refrigerant leakage from the refrigerant circuit by comparing this with a predetermined reference value; A refrigerant leakage detection device comprising: The refrigerant leakage detection device according to claim 7 , further comprising an output unit that outputs a determination result in the determination unit. A refrigerant leakage detection method for detecting refrigerant leakage from a refrigerant circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a liquid storage container are pipe-connected,
Detecting the amount of liquid refrigerant in the liquid reservoir,
Based on this liquid refrigerant amount, measure the operating state quantity of the refrigerant circulating in the refrigerant circuit,
From this measurement result, the amount of excess liquid refrigerant in the liquid reservoir is calculated,
When the opening degree of the expansion valve is smaller than a predetermined value, the refrigerant amount of each element device other than the liquid reservoir container before the compressor stops, and when a predetermined time has elapsed since the compressor stopped Calculate the refrigerant amount of the entire refrigerant circuit from the excess liquid refrigerant amount, and compare this with a predetermined reference value,
A refrigerant leakage detection method that determines that refrigerant is leaking from the refrigerant circuit when the calculation result is smaller than the reference value.

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