JP3852472B2 - Air conditioner - Google Patents

Description

  The present invention relates to a function for determining the suitability of the amount of refrigerant charged in the refrigerant circuit of the air conditioner, and in particular, to a separate type air conditioner in which a heat source unit and a utilization unit are connected via a refrigerant communication pipe. The present invention relates to a function for determining the suitability of the amount of refrigerant charged in the refrigerant circuit.

  Conventionally, there is a separate type air conditioner that includes a heat source unit, a utilization unit, a liquid refrigerant communication pipe and a gas refrigerant communication pipe that connect the heat source unit and the utilization unit. In such an air conditioner, the heat source unit is filled with a predetermined amount of refrigerant in advance, and is insufficient depending on the length of the liquid refrigerant communication pipe and the gas refrigerant communication pipe connecting the heat source unit and the utilization unit at the time of on-site construction. A method of additionally filling the refrigerant to be used is employed. However, since the lengths of the liquid refrigerant communication pipe and the gas refrigerant communication pipe connecting the heat source unit and the utilization unit vary depending on the local situation where the air conditioner is installed, it is difficult to fill the refrigerant with an appropriate amount. There was a case.

On the other hand, during the trial operation after on-site construction, the refrigerant is condensed in the heat source side heat exchanger while performing the cooling operation so that the degree of superheat of the refrigerant evaporated in the use side heat exchanger becomes a predetermined value. There is an air conditioner that has a function of detecting the degree of cooling and determining the suitability of the amount of refrigerant charged in the refrigerant circuit from the value of the degree of supercooling (see, for example, Patent Document 1).
JP-A-62-158966

  However, in the conventional air conditioner having the function of determining the suitability of the refrigerant amount, the degree of superheat of the refrigerant evaporated in the use side heat exchanger according to the operation load of the use unit becomes a predetermined value. Because it only performs cooling operation, it depends on the temperature of the indoor air that exchanges heat with the refrigerant in the use side heat exchanger, the temperature of the outdoor air as a heat source that exchanges heat with the refrigerant in the heat source side heat exchanger, etc. As a result, the pressure of each part in the refrigerant circuit changes, and the target value of the degree of supercooling when determining the suitability of the refrigerant amount changes. For this reason, it is difficult to improve the determination accuracy when determining the suitability of the refrigerant amount.

  In particular, in a multi-type air conditioner equipped with a plurality of use units that can be individually started and stopped, since the operation state of each use unit is not the same, the determination accuracy when determining the suitability of the refrigerant amount is further increased. There is a high possibility that it will become worse, and it is difficult to adopt the function of determining the suitability of the conventional refrigerant amount.

  In the air conditioner, after completing the trial operation and starting the normal operation, the refrigerant in the refrigerant circuit leaks to the outside due to an unexpected cause, and the amount of refrigerant filled in the refrigerant circuit gradually decreases. It can happen. At this time, it is conceivable to detect the leakage of the refrigerant by using the conventional function for determining the appropriateness of the refrigerant amount, but there is a possibility that the presence or absence of the leakage may be misidentified because the determination accuracy is low.

  An object of the present invention is to enable accurate determination of the suitability of the amount of refrigerant charged in a refrigerant circuit in a separate type air conditioner in which a heat source unit and a utilization unit are connected via a refrigerant communication pipe. There is.

An air conditioner according to a first aspect of the present invention includes a refrigerant circuit and an accumulator. The refrigerant circuit includes a heat source unit having a compressor capable of changing an operating capacity and a heat source side heat exchanger, a plurality of usage units having a usage side expansion mechanism and a usage side heat exchanger, a heat source unit and a usage unit. Including a liquid refrigerant communication pipe and a gas refrigerant communication pipe to be connected, and the heat source side heat exchanger is condensed as a refrigerant condenser to be compressed in the compressor, and the use side heat exchanger is condensed in the heat source side heat exchanger. It is possible to perform at least a cooling operation that functions as a refrigerant evaporator. The accumulator is connected to the suction side of the compressor, and can accumulate surplus refrigerant generated in the refrigerant circuit according to the operating load of the utilization unit. The air conditioner has a normal operation mode in which each device of the heat source unit and the utilization unit is controlled according to the operation load of the utilization unit, and the degree of superheat of the refrigerant at the outlet of each utilization-side heat exchanger after all the utilization units are cooled. The operation is switched between the refrigerant quantity determination operation mode for controlling the operation capacity of the compressor so that the evaporation pressure of the refrigerant in the utilization side heat exchanger becomes constant while controlling each utilization side expansion mechanism so that the value becomes positive. Is possible. In the refrigerant amount determination operation mode, the refrigerant amount charged in the refrigerant circuit is detected by detecting the degree of refrigerant subcooling at the outlet of the heat source side heat exchanger or the amount of operating state that varies according to the fluctuation of the degree of subcooling. It is possible to determine the suitability of

This air conditioner is a separate type air conditioner in which a heat source unit and a plurality of utilization units are connected via a refrigerant communication pipe to form a refrigerant circuit, and at least a cooling operation is possible. That is, each usage unit can be started and stopped individually, and during normal operation of the air conditioner (hereinafter referred to as normal operation mode), the operating load required for the air-conditioned space in which each usage unit is arranged is reduced. The operating state will change accordingly. Here, “at least” is because the air conditioner to which the present invention can be applied includes one that can perform another operation such as a heating operation in addition to the cooling operation. In this air conditioner, it is possible to switch between a normal operation such as a cooling operation (hereinafter referred to as a normal operation mode) and a refrigerant amount determination operation mode for forcibly cooling all the use units. The degree of refrigerant subcooling at the outlet of the heat source side heat exchanger or the operating state quantity that fluctuates according to the fluctuation of the degree of supercooling is detected to determine the suitability of the quantity of refrigerant filled in the refrigerant circuit. be able to. Moreover, in this air conditioner, since the refrigerant amount determination operation mode is an operation in which all the use units are cooled, the state where the amount of refrigerant circulating in the refrigerant circuit is forcibly set is set forcibly. It is possible to determine the suitability of the amount of refrigerant charged in the refrigerant circuit by detecting the degree of subcooling of the refrigerant at the outlet of the heat exchanger or the operating state quantity that fluctuates according to the fluctuation of the degree of subcooling.

And the heat source unit of this air conditioning apparatus has the compressor which can vary an operating capacity. For this reason, in the refrigerant quantity determination operation mode in which the use unit is cooled, the superheat degree of each use side heat exchanger functioning as an evaporator is a positive value (that is, the gas refrigerant at the use side heat exchanger outlet is overheated). By controlling each use side expansion mechanism (hereinafter referred to as superheat control) to stabilize the state of the refrigerant flowing in the use side heat exchanger, the use side heat including the gas refrigerant communication pipe Make sure that the gas refrigerant flows in the flow path connecting the exchanger and the compressor, and also control the operating capacity of the compressor so that the evaporation pressure is constant (hereinafter referred to as evaporation pressure control). Thus, the amount of refrigerant flowing in the flow path can be stabilized. Further, in this air conditioner, since the expansion mechanism used for decompressing the refrigerant is provided in the utilization unit as the utilization side expansion mechanism, as a condenser during the cooling operation including the refrigerant amount determination operation mode. The liquid refrigerant condensed in the functioning heat source side heat exchanger is depressurized immediately before the entrance of the use side heat exchanger, and the flow connecting the heat source side heat exchanger including the liquid refrigerant communication pipe and the use side expansion mechanism. The inside of the passage is sealed with the liquid refrigerant. This makes it possible to stabilize the amount of liquid refrigerant flowing in the flow path connecting the heat source side heat exchanger including the liquid refrigerant communication pipe and the utilization side expansion mechanism, and at the outlet of the heat source side heat exchanger. It is possible to improve the determination accuracy when determining the suitability of the amount of refrigerant charged in the refrigerant circuit by detecting the degree of refrigerant subcooling or the amount of operating state that fluctuates in accordance with the degree of subcooling.

  Furthermore, in the air conditioner, it is necessary to include a container for storing surplus refrigerant generated according to the operating load of the utilization unit. In this air conditioner, as described above, a heat source that functions as a condenser In order to achieve compatibility with the adoption of the function of determining the suitability of the refrigerant quantity by detecting the degree of subcooling in the side heat exchanger or the operating state quantity that fluctuates according to the fluctuation of the degree of subcooling, An accumulator is provided. For this reason, there is a concern that the volume of the flow path connecting the use side heat exchanger including the gas refrigerant communication pipe and the accumulator and the compressor is increased, which may adversely affect the determination accuracy of the refrigerant amount. Since superheat degree control and evaporation pressure control are performed, even if the volume of the flow path connecting the compressor and the use side heat exchanger including the gas refrigerant communication pipe and accumulator is large, The amount of refrigerant flowing through can be stabilized. Thus, in spite of the refrigerant circuit provided with the accumulator, the refrigerant cooling circuit at the outlet of the heat source side heat exchanger or the operating state quantity that fluctuates according to the fluctuation of the supercooling degree is detected. It is possible to improve the determination accuracy when determining the suitability of the amount of refrigerant filled in the container.

As described above, according to the present invention, in the separate type air conditioner in which the heat source unit and the plurality of use units are connected via the refrigerant communication pipe, the use side expansion mechanism is operated while cooling all the use units. The refrigerant quantity determination operation mode for performing the superheat degree control by the compressor and the evaporation pressure control by the compressor is provided, and the operation state quantity that varies according to the refrigerant subcooling degree or the fluctuation of the supercooling degree at the outlet of the heat source side heat exchanger is set. By detecting, the suitability of the amount of refrigerant filled in the refrigerant circuit can be accurately determined.

An air conditioner according to a second aspect is the air conditioner according to the first aspect , wherein the operation in the refrigerant amount determination operation mode is periodically performed.

  In this air conditioner, the operation in the refrigerant amount determination operation mode is performed periodically (for example, once a month in the air-conditioned space) while performing cooling operation of the use unit and superheat degree control by the use side expansion mechanism and evaporation pressure control by the compressor. Whether or not the refrigerant in the refrigerant circuit has leaked to the outside due to an unforeseen cause by accurately determining whether or not the amount of refrigerant charged in the refrigerant circuit is accurate. Whether it can be detected.

An air conditioner according to a third aspect of the present invention is the air conditioner according to any one of the first and second aspects, wherein the operation in the refrigerant amount determination operation mode is performed when the refrigerant is charged into the refrigerant circuit.

  In this air conditioner, when the refrigerant is filled in the refrigerant circuit during the cooling operation of the utilization unit and the operation in the refrigerant amount determination operation mode in which the superheat degree control by the utilization side expansion mechanism and the evaporation pressure control by the compressor are performed (for example, In the field, after connecting the heat source unit and the utilization unit via the liquid refrigerant communication pipe and the gas refrigerant communication pipe, additional charging of the insufficient refrigerant according to the length of the liquid refrigerant communication pipe and the gas refrigerant communication pipe, etc. ), It is possible to accurately and quickly perform the refrigerant charging operation by accurately determining whether or not the amount of the refrigerant charged in the refrigerant circuit is appropriate.

An air conditioner according to a fourth aspect of the present invention is the air conditioner according to any of the first to third aspects, wherein the refrigerant circuit further includes a switching mechanism. In the normal operation mode, the switching mechanism includes a cooling operation state, a refrigerant that is condensed in the utilization side heat exchanger as a condenser of refrigerant that is compressed in the compressor, and a heat source side heat exchanger that is condensed in the utilization side heat exchanger. It is possible to switch to a heating operation state that functions as an evaporator. The use side expansion mechanism controls the flow rate of the refrigerant flowing through the use side heat exchanger so that the superheat degree of the refrigerant at the outlet of the use side heat exchanger functioning as an evaporator becomes a predetermined value in the cooling operation state, In the heating operation state, the flow rate of the refrigerant flowing through the use side heat exchanger is controlled so that the degree of supercooling of the refrigerant at the outlet of the use side heat exchanger functioning as a condenser becomes a predetermined value.

  This air conditioner is an air conditioner capable of cooling operation and heating operation by a switching mechanism. In this air conditioner, the use side expansion mechanism flows through the use side heat exchanger so that the degree of superheat of the refrigerant at the outlet of the use side heat exchanger functioning as an evaporator becomes a predetermined value in the cooling operation state. Since the flow rate of the refrigerant is controlled, the liquid refrigerant condensed in the heat source side heat exchanger functioning as a condenser connects the heat source side heat exchanger including the liquid refrigerant communication pipe and the use side expansion mechanism. The flow path will be filled. On the other hand, in the heating operation state, the use side expansion mechanism has a flow rate of the refrigerant flowing through the use side heat exchanger so that the degree of subcooling of the refrigerant at the outlet of the use side heat exchanger functioning as a condenser becomes a predetermined value. Because the control is performed, the liquid refrigerant condensed in the use side heat exchanger functioning as a condenser is decompressed by the use side expansion mechanism to be in a gas-liquid two-phase state, and includes the liquid refrigerant communication pipe. The flow path connecting the heat exchanger and the use side expansion mechanism is filled. That is, in this air conditioner, the amount of liquid refrigerant that fills the flow path connecting the heat source side heat exchanger including the liquid refrigerant communication pipe and the use side expansion mechanism is larger during the cooling operation than during the heating operation. The amount of refrigerant necessary in the refrigerant circuit is determined by the necessary amount of refrigerant during the cooling operation.

  As described above, in the air conditioner capable of the cooling operation and the heating operation, the required refrigerant amount during the cooling operation is larger than the required refrigerant amount during the heating operation. The amount of operating state that varies depending on the degree of refrigerant subcooling or the degree of subcooling at the outlet of the heat source side heat exchanger By detecting this, it is possible to accurately determine the suitability of the amount of refrigerant charged in the refrigerant circuit.

An air conditioner according to a fifth aspect is the air conditioner according to any one of the first to fourth aspects, wherein the compressor is driven by a motor controlled by an inverter.

An air conditioner according to a sixth aspect of the present invention is the air conditioner according to any of the first to fifth aspects, wherein the heat source unit further includes a blower fan that blows air as a heat source to the heat source side heat exchanger. ing. In the refrigerant quantity determination operation mode, the blower fan can control the flow rate of air supplied to the heat source side heat exchanger so that the condensation pressure of the refrigerant in the heat source side heat exchanger becomes a predetermined value.

  This air conditioner includes a heat source unit having a heat source side heat exchanger that uses air as a heat source and a blower fan that blows air as a heat source to the heat source side heat exchanger. The blower fan can control the flow rate of air supplied to the heat source side heat exchanger. Therefore, in the refrigerant quantity determination operation mode, in addition to the superheat degree control by the use side expansion mechanism and the evaporation pressure control by the compressor, the refrigerant pressure is supplied to the heat source side heat exchanger so that the condensation pressure becomes a predetermined value. By controlling the flow rate of air (hereinafter referred to as condensing pressure control), the influence of the temperature of the air can be suppressed and the state of the refrigerant flowing in the heat source side heat exchanger can be stabilized. .

  Thereby, in this air conditioner, in the refrigerant quantity determination operation mode, it is possible to more accurately detect the operating state quantity that fluctuates in accordance with the refrigerant subcooling degree or the subcooling degree fluctuation at the outlet of the heat source side heat exchanger. Therefore, it is possible to improve the determination accuracy when determining the suitability of the refrigerant amount filled in the refrigerant circuit.

An air conditioner according to a seventh aspect is the air conditioner according to the sixth aspect , wherein the blower fan is driven by a DC motor.

  As described above, according to the present invention, the following effects can be obtained.

In the first invention, in the separate type air conditioner in which the heat source unit and the plurality of utilization units are connected via the refrigerant communication pipe, all the utilization units are cooled and the superheat degree control by the utilization side expansion mechanism is performed. Since the refrigerant amount determination operation mode for performing evaporation pressure control by the compressor is provided, the degree of operation state that varies according to the degree of refrigerant subcooling or the degree of subcooling at the outlet of the heat source side heat exchanger is detected. Thus, it is possible to accurately determine whether or not the amount of refrigerant filled in the refrigerant circuit is appropriate.

In the second invention, the refrigerant in the refrigerant circuit is caused by an unforeseen cause by accurately determining the suitability of the refrigerant amount charged in the refrigerant circuit by periodically performing the operation in the refrigerant amount determination operation mode. It is possible to detect whether or not leaked to the outside.

In the third aspect of the invention, by performing the operation in the refrigerant amount determination operation mode when charging the refrigerant in the refrigerant circuit, it is possible to accurately determine whether or not the amount of refrigerant charged in the refrigerant circuit is accurate. Work can be performed accurately and quickly.

In the fourth and fifth inventions, in the air conditioner capable of cooling operation and heating operation, depending on the refrigerant amount determination operation mode, depending on the refrigerant subcooling degree or the fluctuation of the subcooling degree at the outlet of the heat source side heat exchanger Therefore, it is possible to accurately determine whether or not the amount of refrigerant charged in the refrigerant circuit is appropriate.

In the sixth and seventh inventions, in the refrigerant quantity determination operation mode, the flow rate of air supplied to the heat source side heat exchanger can be controlled so that the condensation pressure of the refrigerant in the heat source side heat exchanger becomes a predetermined value. Since it is equipped with an air blower capable of operating, in the refrigerant quantity determination operation mode, it is possible to more accurately detect the operating state quantity that fluctuates depending on the degree of refrigerant subcooling or the degree of subcooling at the outlet of the heat source side heat exchanger. Thus, it is possible to improve the determination accuracy when determining the suitability of the amount of refrigerant charged in the refrigerant circuit.

  Hereinafter, embodiments of an air-conditioning apparatus according to the present invention will be described based on the drawings.

(1) Configuration of Air Conditioner FIG. 1 is a schematic refrigerant circuit diagram of an air conditioner 1 according to an embodiment of the present invention. The air conditioner 1 is a device used for indoor air conditioning such as a building by performing a vapor compression refrigeration cycle operation. The air conditioner 1 mainly includes one heat source unit 2, a plurality of (two in this embodiment) usage units 4 and 5 connected in parallel thereto, and the heat source unit 2 and the usage units 4, 5. And a liquid refrigerant communication pipe 6 and a gas refrigerant communication pipe 7 are provided. That is, the vapor compression refrigerant circuit 10 of the air conditioner 1 of the present embodiment is configured by connecting the heat source unit 2, the utilization units 4 and 5, the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7. It is configured.

<Usage unit>
The usage units 4 and 5 are installed by being embedded or suspended in an indoor ceiling of a building or the like, or wall-mounted on an indoor wall surface. The utilization units 4 and 5 are connected to the heat source unit 2 via the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7 and constitute a part of the refrigerant circuit 10.

  Next, the configuration of the usage units 4 and 5 will be described. Since the usage unit 4 and the usage unit 5 have the same configuration, only the configuration of the usage unit 4 will be described here, and the configuration of the usage unit 5 is the 40th number indicating each part of the usage unit 4. The reference numerals in the 50s are attached instead of the reference numerals, and description of each part is omitted.

  The usage unit 4 mainly includes a usage-side refrigerant circuit 10a (in the usage unit 5, the usage-side refrigerant circuit 10b) that constitutes a part of the refrigerant circuit 10. The use side refrigerant circuit 10 a mainly includes a use side expansion valve 41 (use side expansion mechanism) and a use side heat exchanger 42.

  In the present embodiment, the use side expansion valve 41 is an electric expansion valve connected to the liquid side of the use side heat exchanger 42 in order to adjust the flow rate of the refrigerant flowing in the use side refrigerant circuit 10a.

  In the present embodiment, the use side heat exchanger 42 is a cross-fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins, and functions as a refrigerant evaporator during cooling operation. It is a heat exchanger that cools indoor air and functions as a refrigerant condenser during heating operation to heat indoor air.

  In the present embodiment, the utilization unit 4 includes an indoor fan (not shown) for supplying indoor air as supply air after sucking indoor air into the unit and exchanging heat. It is possible to exchange heat with the refrigerant flowing through the side heat exchanger 42.

  In addition, the utilization unit 4 is provided with various sensors. A liquid side temperature sensor 43 for detecting the temperature of the refrigerant in the liquid state or the gas-liquid two-phase state is provided on the liquid side of the use side heat exchanger 42, and the gas side of the use side heat exchanger 42 is in the gas state. Or the gas side temperature sensor 44 which detects the temperature of the refrigerant | coolant of a gas-liquid two-phase state is provided. In the present embodiment, the liquid side temperature sensor 43 and the gas side temperature sensor 44 are composed of a thermistor. Further, the usage unit 4 includes a usage-side control unit 45 that controls the operation of each unit constituting the usage unit 4. The use-side control unit 45 includes a microcomputer, a memory, and the like provided for controlling the use unit 4, and a remote controller (not shown) for individually operating the use unit 4. Control signals and the like can be exchanged between them, and control signals and the like can be exchanged with the heat source unit 2.

<Heat source unit>
The heat source unit 2 is installed on a rooftop of a building or the like, and is connected to the utilization units 4 and 5 via the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7. The circuit 10 is configured.

  Next, the configuration of the heat source unit 2 will be described. The heat source unit 2 mainly includes a heat source side refrigerant circuit 10 c that constitutes a part of the refrigerant circuit 10. The heat source side refrigerant circuit 10c mainly includes a compressor 21, a four-way switching valve 22, a heat source side heat exchanger 23, an accumulator 24, a liquid side closing valve 25, and a gas side closing valve 26. Yes.

  The compressor 21 is a compressor whose operating capacity can be varied. In this embodiment, the compressor 21 is a positive displacement compressor driven by a motor 21a controlled by an inverter. In the present embodiment, the number of the compressors 21 is only one. However, the present invention is not limited to this, and even if two or more compressors are connected in parallel according to the number of units used, etc. Good.

  The four-way switching valve 22 is a valve for switching the flow direction of the refrigerant. During the cooling operation, the heat source side heat exchanger 23 is used as a refrigerant condenser to be compressed in the compressor 21 and the use side heat exchange. In order to make the units 42 and 52 function as an evaporator for the refrigerant condensed in the heat source side heat exchanger 23, the discharge side of the compressor 21 and the gas side of the heat source side heat exchanger 23 are connected and the compressor 21 The suction side (specifically, the accumulator 24) and the gas refrigerant communication pipe 7 side are connected (see the solid line of the four-way switching valve 22 in FIG. 1), and the use side heat exchangers 42, 52 are connected during heating operation. In order to function as a condenser for the refrigerant compressed in the compressor 21 and as an evaporator for the refrigerant condensed in the utilization side heat exchanger, the discharge side of the compressor 21 and the gas refrigerant are used. Connecting pipe 7 side It is possible to connect the gas side of the suction side and the heat source-side heat exchanger 23 of the compressor 21 as well as continue (see dashed four-way switching valve 22 in FIG. 1).

  In the present embodiment, the heat source side heat exchanger 23 is a cross fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins, and functions as a refrigerant condenser during cooling operation. It is a heat exchanger that functions as a refrigerant evaporator during heating operation. The gas side of the heat source side heat exchanger 23 is connected to the four-way switching valve 22, and the liquid side thereof is connected to the liquid refrigerant communication pipe 6.

  In the present embodiment, the heat source unit 2 includes an outdoor fan 27 (blower fan) for sucking outdoor air into the unit and supplying the air to the heat source side heat exchanger 23 and then discharging the air to the outside. It is possible to exchange heat between the air and the refrigerant flowing through the heat source side heat exchanger 23. The outdoor fan 27 is a fan capable of changing the flow rate of air supplied to the heat source side heat exchanger 23, and is a propeller fan driven by a DC fan motor 27a in the present embodiment.

  The accumulator 24 is connected between the four-way switching valve 22 and the compressor 21, and is a container capable of storing surplus refrigerant generated in the refrigerant circuit 10 according to the operating load of the utilization units 4 and 5. is there.

  The liquid side shutoff valve 25 and the gas side shutoff valve 26 are valves provided at connection ports with external devices and pipes (specifically, the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7). The liquid side closing valve 25 is connected to the heat source side heat exchanger 23. The gas side closing valve 26 is connected to the four-way switching valve 22.

  The heat source unit 2 is provided with various sensors. Specifically, the heat source unit 2 flows through the suction pressure sensor 28 that detects the suction pressure of the compressor 21, the discharge pressure sensor 29 that detects the discharge pressure of the compressor 21, and the heat source side heat exchanger 23. A heat exchange temperature sensor 30 that detects the temperature of the refrigerant, and a liquid side temperature sensor 31 that detects the temperature of the refrigerant in the liquid state or the gas-liquid two-phase state are provided on the liquid side of the heat source side heat exchanger 23. . The heat source unit 2 includes a heat source side control unit 32 that controls the operation of each unit constituting the heat source unit 2. The heat source side control unit 32 includes a microcomputer provided for controlling the heat source unit 2, a memory, an inverter circuit for controlling the motor 21a, and the like. Control signals and the like can be exchanged with 45 and 55.

  As described above, the use side refrigerant circuits 10a and 10b, the heat source side refrigerant circuit 10c, and the refrigerant communication pipes 6 and 7 are connected to form the refrigerant circuit 10 of the air conditioner 1. The air conditioner 1 according to the present embodiment operates by switching between the cooling operation and the heating operation by the four-way switching valve 22, and the heat source unit 2 and the utilization unit according to the operation load of each utilization unit 4, 5. The devices 4 and 5 are controlled.

(2) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 of this embodiment is demonstrated.

  As an operation mode of the air conditioner 1 of the present embodiment, a normal operation mode for controlling each device of the heat source unit 2 and the utilization units 4 and 5 according to an operation load of the utilization units 4 and 5 and a utilization unit. Refrigerant that determines the suitability of the amount of refrigerant charged in the refrigerant circuit 10 by detecting the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23 that functions as a condenser while performing the cooling operation of all 4 and 5 There is a quantity judgment operation mode. The normal operation mode includes a cooling operation and a heating operation, and the refrigerant amount determination operation mode includes a refrigerant automatic charging operation and a refrigerant leakage detection operation.

  Hereinafter, the operation | movement in each operation mode of the air conditioning apparatus 1 is demonstrated.

<Normal operation mode>
First, the cooling operation in the normal operation mode will be described.

  During the cooling operation, the four-way switching valve 22 is in the state shown by the solid line in FIG. 1, that is, the discharge side of the compressor 21 is connected to the gas side of the heat source side heat exchanger 23 and the suction side of the compressor 21 is used. It is in the state connected to the gas side of the side heat exchanger 52. Further, the liquid side shutoff valve 25 and the gas side shutoff valve 26 are opened, and the use side expansion valves 41 and 51 are opened so that the degree of superheat of the refrigerant at the outlets of the use side heat exchangers 42 and 52 becomes a predetermined value. It has come to be adjusted. In this embodiment, the degree of superheat of the refrigerant at the outlets of the use side heat exchangers 42 and 52 is the refrigerant temperature detected by the liquid side temperature sensors 43 and 53 from the refrigerant temperature value detected by the gas side temperature sensors 44 and 54. The refrigerant pressure detected by the gas side temperature sensors 44 and 54 by converting the suction pressure value of the compressor 21 detected by subtracting the value or detected by the suction pressure sensor 28 into the saturation temperature value of the refrigerant. It is detected by subtracting the saturation temperature value of this refrigerant from the value. Although not employed in the present embodiment, a temperature sensor for detecting the temperature of the refrigerant flowing in the use side heat exchangers 42 and 52 is provided, and the refrigerant temperature value detected by the gas side temperature sensors 44 and 54 is used. You may make it detect the superheat degree of the refrigerant | coolant in the exit of the utilization side heat exchangers 42 and 52 by subtracting the refrigerant | coolant temperature value detected by this temperature sensor.

  When the compressor 21 and the outdoor fan 27 are started in the state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become a high-pressure gas refrigerant. Thereafter, the high-pressure gas refrigerant is sent to the heat source side heat exchanger 23 via the four-way switching valve 22 and is condensed by exchanging heat with outdoor air supplied by the outdoor fan 27. It becomes.

  Then, the high-pressure liquid refrigerant is sent to the utilization units 4 and 5 via the liquid-side closing valve 25 and the liquid refrigerant communication pipe 6.

  The high-pressure liquid refrigerant sent to the use units 4 and 5 is reduced in pressure by the use-side expansion valves 41 and 51 to become a low-pressure gas-liquid two-phase refrigerant and sent to the use-side heat exchangers 42 and 52. The use side heat exchangers 42 and 52 exchange heat with indoor air and are evaporated to become low-pressure gas refrigerant. Here, the use side expansion valves 41 and 51 control the flow rate of the refrigerant flowing in the use side heat exchangers 42 and 52 so that the degree of superheat at the outlets of the use side heat exchangers 42 and 52 becomes a predetermined value. Therefore, the low-pressure gas refrigerant evaporated in the use side heat exchangers 42 and 52 has a predetermined degree of superheat. And the refrigerant | coolant of the flow volume according to the driving | running load requested | required in the air-conditioning space in which each utilization unit 4 and 5 was installed flows into each utilization side heat exchanger 42 and 52. FIG.

  This low-pressure gas refrigerant is sent to the heat source unit 2 via the gas refrigerant communication pipe 7 and flows into the accumulator 24 via the gas-side closing valve 26 and the four-way switching valve 22. Then, the low-pressure gas refrigerant that has flowed into the accumulator 24 is again sucked into the compressor 21. Here, depending on the operating load of the usage units 4 and 5, for example, when one operating load of the usage units 4 and 5 is small or stopped, or both the operating loads of the usage units 4 and 5 are When a surplus refrigerant amount is generated in the refrigerant circuit 10 as in the case where the refrigerant is small, the surplus refrigerant is accumulated in the accumulator 24.

  Next, the heating operation in the normal operation mode will be described.

  During the heating operation, the four-way switching 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 gas side of the use side heat exchanger 52 and the suction side of the compressor 21 is the heat source. It is in the state connected to the gas side of the side heat exchanger 23. Further, the liquid side shutoff valve 25 and the gas side shutoff valve 26 are opened, and the use side expansion valves 41 and 51 are opened so that the degree of supercooling of the refrigerant at the outlets of the use side heat exchangers 42 and 52 becomes a predetermined value. The degree is adjusted. In this embodiment, the degree of supercooling of the refrigerant at the outlets of the use side heat exchangers 42 and 52 is calculated by converting the discharge pressure value of the compressor 21 detected by the discharge pressure sensor 29 into the saturation temperature value of the refrigerant. This is detected by subtracting the refrigerant temperature value detected by the liquid side temperature sensors 43 and 53 from the saturation temperature value of the refrigerant. Although not adopted in the present embodiment, a temperature sensor for detecting the temperature of the refrigerant flowing in the use side heat exchangers 42 and 52 is provided, and the liquid side temperature sensor is determined from the refrigerant temperature value detected by the temperature sensor. You may make it detect the supercooling degree of the refrigerant | coolant in the exit of the utilization side heat exchangers 42 and 52 by subtracting the refrigerant | coolant temperature value detected by 43,53.

  When the compressor 21 and the outdoor fan 27 are started in the state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become a high-pressure gas refrigerant, and the four-way switching valve 22 and the gas side closing are performed. It is sent to the utilization units 4 and 5 via the valve 26 and the gas refrigerant communication pipe 7.

  The high-pressure gas refrigerant sent to the utilization units 4 and 5 is condensed by exchanging heat with indoor air in the utilization-side heat exchangers 42 and 52, and then is expanded to the utilization side. The pressure is reduced by the valves 41 and 51 to become a low-pressure gas-liquid two-phase refrigerant. Here, the use side expansion valves 41 and 51 control the flow rate of the refrigerant flowing in the use side heat exchangers 42 and 52 so that the degree of supercooling at the outlets of the use side heat exchangers 42 and 52 becomes a predetermined value. Therefore, the high-pressure liquid refrigerant condensed in the use side heat exchangers 42 and 52 is in a state having a predetermined degree of supercooling. And the refrigerant | coolant of the flow volume according to the driving | running load requested | required in the air-conditioning space in which each utilization unit 4 and 5 was installed flows into each utilization side heat exchanger 42 and 52. FIG.

  This low-pressure gas-liquid two-phase refrigerant is sent to the heat source unit 2 via the liquid refrigerant communication pipe 6 and flows into the heat source side heat exchanger 23 via the liquid side closing valve 25. The low-pressure gas-liquid two-phase refrigerant flowing into the heat source side heat exchanger 23 is condensed by exchanging heat with the outdoor air supplied by the outdoor fan 27 to form a low-pressure gas refrigerant. It flows into the accumulator 24 via 22. Then, the low-pressure gas refrigerant that has flowed into the accumulator 24 is again sucked into the compressor 21. Here, depending on the operating load of the usage units 4 and 5, for example, when one operating load of the usage units 4 and 5 is small or stopped, or both the operating loads of the usage units 4 and 5 are When a surplus refrigerant amount is generated in the refrigerant circuit 10 as in the case where the refrigerant is small, the surplus refrigerant is accumulated in the accumulator 24 as in the cooling operation.

<Refrigerant amount judgment operation mode>
First, the refrigerant automatic charging operation which is one of the refrigerant quantity determination operation modes will be described with reference to FIGS. Here, FIG. 2 is a schematic diagram showing the state of the refrigerant flowing in the refrigerant circuit in the refrigerant quantity determination operation mode (illustration of a four-way switching valve and the like is omitted). FIG. 3 is a flowchart at the time of the refrigerant automatic charging operation.

  In the field, after connecting the heat source unit 2 pre-filled with the refrigerant and the utilization units 4 and 5 via the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7 to form the refrigerant circuit 10, the liquid refrigerant communication pipe 6 and a case where additional refrigerant is additionally filled in the refrigerant circuit 10 according to the length of the gas refrigerant communication pipe 7 will be described.

  First, the liquid side closing valve 25 and the gas side closing valve 26 of the heat source unit 2 are opened, and the refrigerant circuit 10 is filled with the refrigerant preliminarily charged in the heat source unit 2.

  Next, the person who performs the refrigerant filling operation directly through the remote controller (not shown) or directly to the use side control units 45 and 55 of the use units 4 and 5 and the heat source side control unit 32 of the heat source unit 2, When a command is issued to perform the automatic refrigerant charging operation, which is one of the refrigerant quantity determination operation modes, the automatic refrigerant charging operation is performed in the following steps S1 to S4.

<Step S1, cooling operation of all used units>
When an instruction to start the automatic refrigerant charging operation is made, the refrigerant circuit 10 is in a state where the four-way switching valve 22 of the heat source unit 2 is shown by a solid line in FIG. , 51 are opened, the compressor 21 and the outdoor fan 27 are activated, and the cooling operation is forcibly performed for all the usage units 4 and 5.

  Then, as shown in FIG. 2, in the refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged in the compressor 21 in the flow path from the compressor 21 to the heat source side heat exchanger 23 that functions as a condenser. Flows (see sand hatching in FIG. 2), and a high-pressure refrigerant that changes phase from a gas state to a liquid state flows through heat exchange with outdoor air in the heat source side heat exchanger 23 functioning as a condenser (see FIG. 2). No. 2 sand hatching and black hatching (hereinafter referred to as the condenser part A), and the flow path including the liquid refrigerant communication pipe 6 from the heat source side heat exchanger 23 to the use side expansion valves 41 and 51 has a high pressure. Liquid refrigerant flows (see black hatching in FIG. 2, hereinafter referred to as liquid refrigerant communication portion B), and the use side heat exchangers 42 and 52 functioning as evaporators are evacuated by heat exchange with indoor air. Phase change from liquid two-phase state to gas state The low-pressure refrigerant flows (see the lattice hatching and the hatched hatching in FIG. 2, hereinafter referred to as the evaporator section C), the gas refrigerant communication pipe 7 and the accumulator 24 from the use side heat exchangers 42 and 52 to the compressor 21. The low-pressure gas refrigerant flows through the flow path including the gas (see the hatched area in FIG. 2, hereinafter referred to as the gas refrigerant communication portion D).

<Step S2, control for stabilizing the state of the refrigerant in each part of the refrigerant circuit>
Next, the following device control is performed to shift to an operation for stabilizing the state of the refrigerant circulating in the refrigerant circuit 10. Specifically, the flow rate of outdoor air supplied to the heat source side heat exchanger 23 by the outdoor fan 27 is controlled so that the condensation pressure of the refrigerant in the heat source side heat exchanger 23 becomes a predetermined value (hereinafter referred to as condensing pressure control). And the use side heat exchangers 42 and 52 functioning as evaporators have a positive value of superheat (that is, the gas refrigerant at the outlets of the use side heat exchangers 42 and 52 is overheated). The expansion valves 41 and 51 are controlled (hereinafter referred to as superheat control), and the operation capacity of the compressor is controlled (hereinafter referred to as evaporation pressure control) so that the evaporation pressure becomes constant.

  Here, the condensation pressure control is performed because the refrigerant amount in the condenser part A greatly affects the refrigerant condensation pressure in the condenser part A, as shown in FIG. And since the condensing pressure of the refrigerant in the condenser section A changes more greatly than the influence of the temperature of the outdoor air, the flow rate of the outdoor air supplied from the outdoor fan 27 to the heat source side heat exchanger 23 is controlled by the DC fan motor 27a. By setting the refrigerant condensation pressure in the heat source side heat exchanger 23 to a predetermined value (for example, the condensation pressure Pa when determining the suitability of the amount of refrigerant charged), the state of the refrigerant flowing in the condenser section A The amount of refrigerant changes depending on the degree of supercooling (SC). In the present embodiment, since a pressure sensor that directly detects the pressure of the refrigerant in the heat source side heat exchanger 23 is not provided, the control of the condensation pressure by the outdoor fan 27 is detected by the discharge pressure sensor 29. The discharge pressure of the compressor 21 is used instead of the refrigerant condensation pressure in the heat source side heat exchanger 23.

  And by performing such condensing pressure control, since the pressure of the refrigerant | coolant in the liquid refrigerant communication part B is also stabilized, the liquid refrigerant communication part B will be sealed with the liquid refrigerant, and will be in the stable state. As shown in FIG. 5, the refrigerant amount in the liquid refrigerant communication unit B is insensitive to changes in the refrigerant pressure and the refrigerant subcooling (SC) in the liquid refrigerant communication unit B.

  The reason why the evaporation pressure control is performed is that the amount of refrigerant in the evaporator section C greatly affects the evaporation pressure of the refrigerant in the evaporator section C, as shown in FIG. The refrigerant evaporating pressure in the evaporator section C is set to a predetermined value by controlling the operating capacity of the compressor 21 by the motor 21a controlled by the inverter, thereby setting the evaporating pressure of the refrigerant in the use side heat exchangers 42 and 52 to a predetermined value. For example, the state of the refrigerant flowing in the evaporator section C is stabilized by using (e.g., the evaporation pressure Pc when determining the suitability of the charged refrigerant amount). In the present embodiment, a pressure sensor that directly detects the refrigerant pressure in the use side heat exchangers 42 and 52 is not provided. Therefore, in the control of the evaporation pressure by the compressor 21, the suction pressure sensor 28 detects the refrigerant pressure. The suction pressure of the compressor 21 is used instead of the refrigerant evaporation pressure in the use side heat exchangers 42 and 52.

  Further, the superheat control is performed together with the evaporation pressure control as described above, as shown in FIG. 6, the amount of refrigerant in the evaporator section C is determined by the dryness of the refrigerant at the outlets of the use side heat exchangers 42 and 52. This is because it greatly affects. The degree of superheat of the refrigerant at the outlets of the use side heat exchangers 42 and 52 is controlled by controlling the opening degree of the use side expansion valves 41 and 51, so that the degree of superheat of the refrigerant at the outlets of the use side heat exchangers 42 and 52 ( SH) is set to a positive value (that is, the gas refrigerant at the outlets of the use side heat exchangers 42 and 52 is overheated), and the state of the refrigerant flowing in the evaporator section C is stabilized. Unlike the superheat control in the normal operation mode, the superheat control in the refrigerant quantity determination operation mode may be a positive value of the superheat of the refrigerant at the outlets of the use side heat exchangers 42 and 52. This is because in the superheat control in the normal operation mode, in order to adjust the flow rate of the refrigerant flowing through the use side heat exchangers 42 and 52 according to the operation load of the use units 4 and 5, Although it is necessary to control the superheat degree of the refrigerant at the outlet to a predetermined value, in the superheat degree control in the refrigerant quantity determination operation mode, as shown in FIG. This is because the refrigerant at the outlets of the use side heat exchangers 42 and 52 does not have to be in a wet state (that is, in a state where the dryness is less than 1).

  And by performing such evaporation pressure control and superheat degree control, since the pressure of the refrigerant in the gas refrigerant communication part D becomes stable and the gas refrigerant flows reliably, it flows through the gas refrigerant communication part D. The state of the refrigerant is also stabilized. As shown in FIG. 7, the amount of refrigerant in the gas refrigerant communication part D largely depends on the pressure and superheat (SH) of the refrigerant in the gas refrigerant communication part D, but the above evaporation pressure control and superheat degree control. Is stable.

  While performing control to stabilize the state of the refrigerant circulating in the refrigerant circuit 10 as described above, the refrigerant circuit 10 is additionally charged with the refrigerant.

<Step S3, detection of supercooling degree>
Next, the degree of supercooling at the outlet of the heat source side heat exchanger 23 is detected. In the present embodiment, the degree of supercooling of the refrigerant at the outlet of the heat source side heat exchanger 23 is obtained by subtracting the refrigerant temperature value detected by the liquid side temperature sensor 31 from the refrigerant temperature value detected by the heat exchange temperature sensor 30. The discharge pressure value of the compressor 21 detected or detected by the discharge pressure sensor 29 is converted into the saturation temperature value of the refrigerant, and the refrigerant temperature detected by the liquid side temperature sensor 31 from the saturation temperature value of the refrigerant Detected by subtracting the value.

<Step S4, Determination of Appropriate Refrigerant Quantity>
Next, the suitability of the refrigerant amount is determined from the value of the degree of supercooling detected in step S3. Here, when detecting the degree of supercooling in step S3, the liquid refrigerant communication unit B, the evaporator unit C, and the gas refrigerant communication unit are controlled by stabilizing the state of the refrigerant circulating in the refrigerant circuit 10 in step S2. The amount of refrigerant in D is constant, and only the amount of refrigerant in the condenser part A is in a state that changes due to additional charging of the refrigerant. That is, regardless of the form of the usage units 4 and 5 and the length of the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7, the refrigerant amount (specifically, the heat source side heat exchanger 23 of the heat source side heat exchanger 23). The suitability of the amount of refrigerant charged in the refrigerant circuit 10 can be determined by the degree of refrigerant supercooling at the outlet.

  First, when the amount of refrigerant to be additionally charged is small and has not reached the necessary amount of refrigerant, the refrigerant amount in the condenser section A is small in step S2. Here, the state in which the amount of refrigerant in the condenser part A is small means that the supercooling degree value detected in step S3 corresponds to the supercooling degree value (hereinafter referred to as the refrigerant quantity required for the condensation pressure Pa in the condenser part A). It is smaller than the target supercooling degree value. For this reason, when the supercooling degree value detected in step S3 is smaller than the target supercooling degree value and the refrigerant charging is not completed, the above-described steps are performed until the supercooling degree value reaches the target supercooling degree value. The process of S2 and this step S3 is repeated.

  This automatic refrigerant charging operation is used not only for refrigerant charging during trial operation after on-site construction, but also for additional charging of refrigerant when the amount of refrigerant charged in the refrigerant circuit 10 decreases due to refrigerant leakage or the like. Is possible.

  Next, the refrigerant leakage detection operation which is one of the refrigerant quantity determination operation modes will be described with reference to FIGS. 1, 2, 4 to 7 and 8. Here, FIG. 8 is a flowchart in the refrigerant leak detection operation.

  Here, the refrigerant leakage detection operation, which is one of the refrigerant quantity determination operation modes, is performed periodically (for example, when a load is not required for the air-conditioned space once a month) during the cooling operation or the heating operation in the normal operation mode. A case will be described as an example in which it is detected whether or not the refrigerant in the refrigerant circuit has leaked to the outside due to an unexpected cause by switching to.

<Step S11, Determination of whether or not the normal operation mode has elapsed for a certain period of time>
First, it is determined whether or not the operation in the normal operation mode such as the cooling operation and the heating operation described above has passed for a certain period of time (every month, etc.). The process proceeds to step S12.

<Step S12, cooling operation of all used units>
When the operation in the normal operation mode has elapsed for a certain period of time, the refrigerant circuit 10 and the four-way switching valve 22 of the heat source unit 2 are indicated by the solid line in FIG. 1 as in step S1 of the automatic refrigerant charging operation. In addition, the utilization side expansion valves 41 and 51 of the utilization units 4 and 5 are opened, the compressor 21 and the outdoor fan 27 are activated, and all the utilization units 4 and 5 are forcibly cooled. Performed (see FIG. 2).

<Step S13, Control for Stabilizing Refrigerant State in Each Part of Refrigerant Circuit>
Next, similarly to step S2 of the refrigerant automatic charging operation, the condensation pressure control by the outdoor fan 27, the superheat degree control by the use side expansion valves 41 and 51, and the evaporation pressure control by the compressor are performed, and the refrigerant circuit 10 The state of the refrigerant circulating inside is stabilized.

<Step S14, detection of supercooling degree>
Next, the degree of supercooling at the outlet of the heat source side heat exchanger 23 is detected as in step S3 of the automatic refrigerant charging operation.

<Steps S15, S16, S17, determination of appropriateness of refrigerant amount, return to normal operation mode, warning display>
Next, as in step S4 of the automatic refrigerant charging operation, the suitability of the refrigerant amount is determined from the value of the degree of supercooling detected in step S14.

  Specifically, the supercooling degree value detected in step S14 is substantially the same as the target supercooling degree value (for example, the difference between the detected supercooling degree value and the target supercooling degree value is less than a predetermined value). In some cases, it is determined that there is no refrigerant leakage, and the process proceeds to the next step S16 to return to the normal operation mode.

  On the other hand, when the supercooling degree value detected in step S14 is smaller than the target supercooling degree value (for example, the difference between the detected supercooling degree value and the target supercooling degree value is a predetermined value or more). Is determined that a refrigerant leak has occurred, the process proceeds to step S17, a warning is displayed to notify that a refrigerant leak has been detected, and then the process proceeds to step S16. Return to normal operation mode.

  In this refrigerant leak detection operation, after the refrigerant state suitable for determining the suitability of the refrigerant amount filled in the refrigerant circuit 10 is forcibly created and stabilized, the suitability of the refrigerant amount is judged. Therefore, when determining the suitability of the refrigerant amount, it is not necessary to refer to the previous determination result or the like. For this reason, a memory or the like for storing the change over time of the refrigerant amount is unnecessary.

  In addition, as shown in FIG. 9, the air conditioner 1 capable of performing the refrigerant leak detection operation is connected to the air conditioning controller 61 and connected to the remote server 63 of the information management center via the network 62. Various operation data including device abnormality information such as the result of the refrigerant leak detection operation is transmitted, and the remote server 63 transmits various operation data including the device abnormality information to the information terminal 64 of the service station having jurisdiction over the air conditioner 1. In addition, a remote management system may be constructed. As a result, it is possible to provide a service such as reporting a refrigerant leak detection operation result of the air conditioner 1 to an administrator of the air conditioner 1 or dispatching a service person when refrigerant leak is detected. Become.

(3) Features of the air conditioner The air conditioner 1 of the present embodiment has the following features.

(A)
In the air conditioner 1 of the present embodiment, the heat source unit 2 and the utilization unit 5 are connected via the refrigerant communication pipes 6 and 7 to constitute the refrigerant circuit 10, and the cooling / heating switching operation (that is, at least the cooling operation). It is a separate type air conditioner that can be used. Moreover, the air conditioner 1 is a multi-type air conditioner that includes a plurality of use units 4 and 5 having use side expansion valves 41 and 51. That is, each usage unit 4 and 5 can be started and stopped individually, and during normal operation of the air-conditioning apparatus 1 (hereinafter referred to as normal operation mode), the air conditioning in which each usage unit 4 and 5 is arranged. The driving state changes according to the driving load required for the space. On the other hand, in this air conditioner 1, since it is possible to operate by switching between the normal operation mode and the refrigerant amount determination operation mode in which all the use units 4 and 5 are cooled, After forcibly setting a state in which the amount of refrigerant circulating in the refrigerant circuit 10 is maximized, the refrigerant circuit 10 is filled by detecting the degree of supercooling of the refrigerant at the outlet of the heat source side heat exchanger 23. Appropriateness of the refrigerant amount can be determined.

(B)
Moreover, the heat source unit 2 of the air conditioner 1 has a compressor 21 whose operating capacity can be varied. For this reason, in the refrigerant quantity determination operation mode in which all the usage units 4 and 5 are cooled, the superheating degree of the usage side heat exchangers 42 and 52 functioning as an evaporator is a positive value (that is, the usage side heat exchanger 42. , By controlling the use side expansion valves 41 and 51 so that the gas refrigerant at the outlet 52 becomes superheated (hereinafter referred to as superheat degree control), the state of the refrigerant flowing in the evaporator section C is stabilized. By making sure that the gas refrigerant flows into the gas refrigerant communication section D and further controlling the operation capacity of the compressor 21 so that the evaporation pressure is constant (hereinafter referred to as evaporation pressure control), the gas refrigerant The amount of refrigerant flowing in the communication part D can be stabilized. Moreover, in this air conditioning apparatus 1, since the expansion mechanism used for decompressing the refrigerant is provided in the utilization units 4 and 5 as the utilization side expansion valves 41 and 51, the cooling including the refrigerant amount determination operation mode is performed. During operation, the liquid refrigerant condensed in the heat source side heat exchanger 23 functioning as a condenser is decompressed immediately before the entrance of the use side heat exchangers 42 and 52, and the liquid refrigerant communication section B is liquid refrigerant. It will be sealed. This makes it possible to stabilize the amount of liquid refrigerant flowing in the liquid refrigerant communication portion B, and as a result, only by determining the suitability of the refrigerant amount in the condenser portion A, the form of the usage units 4 and 5 Since the adequacy of the amount of refrigerant charged in the refrigerant circuit 10 can be determined regardless of the length of the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7, the outlet of the heat source side heat exchanger 23 can be determined. It is possible to improve the determination accuracy when determining the appropriateness of the amount of refrigerant charged in the refrigerant circuit 10 by detecting the degree of supercooling of the refrigerant in the refrigerant circuit 10. In addition, as the compressor 21 of this embodiment, the compressor driven by the motor 21a controlled by an inverter is employ | adopted.

(C)
Moreover, the air conditioning apparatus 1 of this embodiment can perform a cooling operation and a heating operation by a four-way switching valve 22 as a switching mechanism. And in this air conditioning apparatus 1, in the cooling operation state, the use side expansion valves 41 and 51 are set so that the degree of superheat of the refrigerant at the outlet of the use side heat exchangers 42 and 52 functioning as an evaporator becomes a predetermined value. Since the flow rate of the refrigerant flowing through the use side heat exchangers 42 and 52 is controlled, the liquid refrigerant condensed in the heat source side heat exchanger 23 functioning as a condenser fills the liquid refrigerant communication portion B. become. On the other hand, in the heating operation state, the use side heat exchangers 41 and 51 use the heat exchangers on the use side so that the degree of supercooling of the refrigerant at the outlets of the use side heat exchangers 42 and 52 functioning as condensers becomes a predetermined value. Since the flow rate of the refrigerant flowing through 42 and 52 is controlled, the liquid refrigerant condensed in the use side heat exchangers 42 and 52 functioning as a condenser is decompressed by the use side expansion valves 41 and 51 and is It will be in a liquid two phase state and will fill the inside of liquid refrigerant connecting part B. That is, in this air conditioner 1, since the amount of liquid refrigerant that fills the liquid refrigerant communication portion B is larger during the cooling operation than during the heating operation, the amount of refrigerant required in the refrigerant circuit 10 is the amount during the cooling operation. It will be determined by the required amount of refrigerant.

  As described above, in the air-conditioning apparatus 1 of the present embodiment, the required refrigerant amount during the cooling operation is larger than the required refrigerant amount during the heating operation. By detecting the degree of supercooling of the refrigerant at the outlet of the heat source side heat exchanger 23 by the refrigerant amount determination operation mode in which the superheat degree control by the valves 41 and 51 and the evaporation pressure control by the compressor 21 are performed, the refrigerant circuit 10 includes The suitability of the amount of refrigerant filled can be accurately determined.

(D)
The air conditioner 1 of the present embodiment includes a heat source unit 2 having a heat source side heat exchanger 23 that uses air as a heat source and an outdoor fan 27 that blows air as a heat source to the heat source side heat exchanger 23. I have. The outdoor fan 27 can control the flow rate of air supplied to the heat source side heat exchanger 23. For this reason, in the refrigerant quantity determination operation mode, in addition to the superheat degree control by the use side expansion valves 41 and 51 and the evaporation pressure control by the compressor 21, the heat source side heat exchange is performed so that the condensation pressure becomes a predetermined value. By controlling the flow rate of air supplied to the heat exchanger 23 (hereinafter referred to as condensing pressure control), the influence of the temperature of the outdoor air is suppressed, and the state of the refrigerant flowing in the heat source side heat exchanger 23 is stabilized. Can be done.

  Thereby, in this air conditioning apparatus 1, in the refrigerant quantity determination operation mode, the refrigerant subcooling degree at the outlet of the heat source side heat exchanger 23 can be detected with higher accuracy, so that the refrigerant circuit 10 is filled. It is possible to improve the determination accuracy when determining the suitability of the refrigerant amount. Note that a fan driven by a DC motor is used as the outdoor fan 27 of the present embodiment.

(E)
Furthermore, in the multi-type air conditioner, it is necessary to provide a container for storing surplus refrigerant generated according to the operating load of the utilization units 4 and 5, but in this air conditioner 1, as described above, The heat source unit 2 is provided with an accumulator 24 in order to achieve compatibility with the function of determining the suitability of the refrigerant amount by detecting the degree of supercooling in the heat source side heat exchanger 23 functioning as a condenser. I have to. For this reason, the volume of the flow path (namely, gas refrigerant communication part D) which connects the use side heat exchangers 42 and 52 including the gas refrigerant communication pipe 7 and the accumulator 24 and the compressor 21 is increased, and the amount of refrigerant is reduced. Although there is a concern that the determination accuracy of the suitability may be adversely affected, since the superheat degree control and the evaporation pressure control are performed, the gas refrigerant communication unit D can be used even when the volume of the gas refrigerant communication unit D is large. The amount of flowing refrigerant can be stabilized. Thus, despite the refrigerant circuit 10 having the accumulator 24, the degree of refrigerant cooling in the refrigerant circuit 10 can be determined by detecting the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23. The determination accuracy at the time of determination can be improved.

(F)
In the air conditioner 1 of the present embodiment, the refrigerant quantity determination operation mode is performed in which all the use units 4 and 5 are cooled and the superheat degree control by the use side expansion valves 41 and 51 and the evaporation pressure control by the compressor 21 are performed. By performing one refrigerant leak detection operation periodically (for example, when a load is not required in the air-conditioned space once a month), it is possible to accurately determine whether or not the amount of refrigerant charged in the refrigerant circuit 10 is appropriate. By determining, it is possible to detect whether or not the refrigerant in the refrigerant circuit 10 has leaked to the outside due to an unexpected cause.

  Further, in this refrigerant leak detection operation, after the state of the refrigerant suitable for judging the suitability of the refrigerant amount filled in the refrigerant circuit 10 is forcibly created and stabilized, the suitability of the refrigerant quantity is judged. Therefore, when determining the suitability of the refrigerant amount, it is not necessary to refer to the previous determination result or the like. For this reason, a memory or the like for storing the change over time of the refrigerant amount is unnecessary.

(G)
In the air conditioner 1 of the present embodiment, in the refrigerant amount determination operation mode in which all the use units 4 and 5 are cooled, the superheat degree control by the use side expansion valves 41 and 51 and the evaporation pressure control by the compressor 21 are performed. When the refrigerant is charged into the refrigerant circuit 10 in one refrigerant automatic charging operation (for example, in the field, the heat source unit 2 and the utilization units 4 and 5 are connected via the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7. After the connection, the suitability of the amount of the refrigerant filled in the refrigerant circuit 10 is determined by performing an additional filling of the refrigerant that is insufficient according to the length of the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7. By accurately determining, the refrigerant filling operation can be performed accurately and quickly.

(4) Modification 1
In the air conditioning apparatus 1 described above, the suitability of the refrigerant amount at the time of automatic refrigerant charging and refrigerant leakage detection is determined by detecting the degree of supercooling of the refrigerant at the outlet of the heat source side heat exchanger 23. The suitability of the refrigerant quantity may be determined by detecting not the supercooling degree itself but another operating state quantity that varies with the fluctuation of the supercooling degree.

  For example, when performing the above-described superheat degree control and evaporation pressure control (preferably further condensing pressure control), if the degree of supercooling of the refrigerant at the outlet of the heat source side heat exchanger 23 increases, the use side expansion Since the dryness of the refrigerant flowing into the use-side heat exchangers 42 and 52 after being expanded by the valves 41 and 51 is lowered, the opening degree of the use-side expansion valves 41 and 51 performing superheat degree control tends to be small. Appears. Utilization of such characteristics, that is, utilization side expansion as one of other operating state quantities that vary with the variation in the degree of supercooling instead of the degree of refrigerant supercooling at the outlet of the heat source side heat exchanger 23 The suitability of the amount of refrigerant charged in the refrigerant circuit 10 can also be determined using the opening degrees of the valves 41 and 51.

  Further, as a criterion for determining the suitability of the refrigerant amount, the refrigerant amount is obtained by using both the determination result based on the degree of supercooling at the outlet of the heat source side heat exchanger 23 and the determination result based on the opening degree of the use side expansion valves 41 and 51. The suitability of the refrigerant amount may be determined by a combination of the degree of supercooling and other operating state quantities that vary with changes in the degree of supercooling.

(5) Modification 2
In the above-described refrigerant leak detection operation, as shown in FIG. 8 and the description thereof, a case where control is performed to switch between the normal operation mode and the refrigerant amount determination operation mode at a constant time interval is given as an example. It is not limited to this.

  For example, instead of being controlled, the air conditioner 1 is provided with a switch or the like for switching to the refrigerant amount determination operation mode, and a serviceman or facility manager operates the switch or the like locally. The refrigerant leakage detection operation may be performed periodically.

  In the description of the refrigerant leakage detection operation described above, “the refrigerant amount after forcibly creating and stabilizing the refrigerant state suitable for determining the suitability of the refrigerant amount charged in the refrigerant circuit 10”. However, there is no need to refer to the previous determination result or the like when determining the suitability of the refrigerant amount, ”this explains the advantage of the present invention. It is intended to make the best use of it. For example, the judgment of the presence or absence of refrigerant leakage can be made based on the results obtained in multiple refrigerant leakage detection operations or the previous judgment due to restrictions of laws and standards, etc. It is not excluded to make a determination based on a deviation from the result of the time or to make a determination using the result immediately after charging the refrigerant. In such a case, data such as a change in the refrigerant amount with time is stored. A memory is provided.

(6) Other Embodiments While 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. It is.

  For example, in the above-described embodiment, an example in which the present invention is applied to an air conditioner capable of switching between heating and cooling has been described. However, the present invention is not limited thereto, and can be applied to a separate type air conditioner, and is a pair type. The present invention may be applied to an air conditioner, an air conditioner dedicated to cooling, or an air conditioner capable of simultaneous cooling and heating.

  As an example, an embodiment in which the present invention is applied to an air conditioner capable of simultaneous cooling and heating will be described below.

  FIG. 10 is a schematic refrigerant circuit diagram of the air-conditioning apparatus 101 capable of simultaneous cooling and heating. The air conditioner 101 mainly includes a plurality of (in this case, two) use units 4 and 5, a heat source unit 102, and refrigerant communication pipes 6, 7, and 8.

  The utilization units 4 and 5 are connected to the heat source unit 102 via the liquid refrigerant communication pipe 6, the intake gas communication pipe 7 as the gas refrigerant communication pipe, the discharge gas communication pipe 8, and the connection units 14 and 15. A refrigerant circuit 110 is configured with the unit 102. In addition, since the utilization units 4 and 5 are the same structures as the utilization units 4 and 5 of the above-mentioned air conditioning apparatus 1, description is abbreviate | omitted.

  The heat source unit 102 is connected to the usage units 4 and 5 via the refrigerant communication pipes 6, 7 and 8, and constitutes a refrigerant circuit 110 between the usage units 4 and 5. Next, the configuration of the heat source unit 102 will be described. The heat source unit 102 mainly constitutes a part of the refrigerant circuit 110 and includes a heat source side refrigerant circuit 110c. The heat source side refrigerant circuit 110c mainly includes a compressor 21, a three-way switching valve 122, a heat source side heat exchanger 23, an accumulator 24, an outdoor fan 27, and closing valves 25, 26, and 33. Yes. Here, since the other devices and valves other than the three-way switching valve 122 and the shut-off valve 33 have the same configuration as the devices and valves of the heat source unit 2 of the air conditioner 1 described above, description thereof will be omitted.

  The three-way switching valve 122 connects the discharge side of the compressor 21 and the gas side of the heat source side heat exchanger 23 when the heat source side heat exchanger 23 functions as a condenser (hereinafter referred to as a condensation operation state). When the heat source side heat exchanger 23 functions as an evaporator (hereinafter referred to as an evaporation operation state), the heat source is connected so that the suction side of the compressor 21 and the gas side of the heat source side heat exchanger 23 are connected. It is a valve for switching the flow path of the refrigerant in the side refrigerant circuit 110c. A discharge gas communication pipe 8 is connected between the discharge side of the compressor 21 and the three-way switching valve 122. A discharge gas closing valve 33 is connected to the discharge gas communication pipe 8. As a result, the high-pressure gas refrigerant compressed and discharged by the compressor 21 can be supplied to the utilization units 4 and 5 regardless of the switching operation of the three-way switching valve 122. An intake gas communication pipe 7 through which a low-pressure gas refrigerant returning from the utilization units 4 and 5 flows is connected to the suction side of the compressor 21.

  The heat source unit 102 is provided with various sensors and the heat source side control unit 32, which are also similar in configuration to the various sensors and the heat source side control unit 32 of the air conditioning apparatus 1 described above. Therefore, the description is omitted.

  The use units 4 and 5 are connected to the gas side of the use side heat exchangers 42 and 52 via the connection units 14 and 15 so as to be switchable to the discharge gas communication pipe 8 and the intake gas communication pipe 7. The connection units 14 and 15 mainly include cooling / heating switching valves 71 and 81. The cooling / heating switching valves 71, 81 connect the gas side of the usage side heat exchangers 42, 52 of the usage units 4, 52 and the intake gas communication pipe 7 when the usage units 4, 5 perform the cooling operation ( Hereinafter, when the usage units 4 and 5 perform the heating operation, the gas side of the usage side heat exchangers 42 and 52 of the usage units 4 and 5 and the discharge gas communication pipe 8 are connected. It is a valve that functions as a switching mechanism that switches between a state (hereinafter referred to as a heating operation state).

  With such a configuration of the air conditioner 101, the use units 4 and 5 perform so-called simultaneous cooling and heating operations, for example, heating the sensible heat system use unit 5 while cooling the use unit 4. Is possible.

  Also in the air conditioner 101 that can be operated simultaneously with cooling and heating, in the refrigerant quantity determination operation mode, the three-way switching valve 122 is set in the condensing operation state so that the heat source side heat exchanger 23 functions as a refrigerant condenser. By switching the switching valves 71 and 81 to the cooling operation state and causing the use side heat exchangers 42 and 52 to function as a refrigerant evaporator, all the use units 4 and 5 are cooled and the use side expansion valves 41 and 51 are operated. It is possible to perform superheat control by means of, evaporative pressure control by means of the compressor 21 and the like. Thereby, similarly to the above-described air conditioner 1, the refrigerant circuit 110 is detected by detecting the degree of subcooling of the refrigerant at the outlet of the heat source side heat exchanger 23 or the amount of operating state that varies according to the fluctuation of the degree of subcooling. Appropriateness of the amount of refrigerant filled in the inside can be accurately determined.

  By using the present invention, in a separate type air conditioner in which a heat source unit and a utilization unit are connected via a refrigerant communication pipe, it is possible to accurately determine the suitability of the amount of refrigerant charged in the refrigerant circuit. can do.

1 is a schematic refrigerant circuit diagram of an air-conditioning apparatus according to an embodiment of the present invention. It is a schematic diagram (illustration of a four-way switching valve etc. is abbreviate | omitted) which shows the state of the refrigerant | coolant which flows through the refrigerant circuit in refrigerant | coolant amount determination operation mode. It is a flowchart at the time of a refrigerant | coolant automatic filling driving | operation. It is a graph which shows the relationship between the refrigerant | coolant amount in a condenser part, the condensation pressure of the refrigerant | coolant in a condenser part, and the supercooling degree in the exit of a heat source side heat exchanger. It is a graph which shows the relationship between the refrigerant | coolant amount in a liquid refrigerant communication part, the pressure of the refrigerant | coolant in a liquid refrigerant communication part, and the subcooling degree of the refrigerant | coolant in a liquid refrigerant communication part. It is a graph which shows the relationship between the refrigerant | coolant amount in an evaporator part, the evaporation pressure of the refrigerant | coolant in an evaporator part, and the superheat degree (and dryness) in the exit of a utilization side heat exchanger. It is a graph which shows the relationship between the refrigerant | coolant amount in a gas refrigerant communication part, the pressure of the refrigerant | coolant in a gas refrigerant communication part, and the superheat degree (and dryness) of the refrigerant | coolant in a gas refrigerant communication part. It is a flowchart at the time of a refrigerant | coolant leak detection driving | operation. It is a block diagram of the remote management system of an air conditioning apparatus. It is a refrigerant circuit diagram of the outline of the air conditioning apparatus of other embodiment concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Air conditioning apparatus 2,102 Heat source unit 4,5 Use unit 6 Liquid refrigerant communication pipe 7 Gas refrigerant communication pipe 10,110 Refrigerant circuit 21 Compressor 21a Motor 22,122,71,81 Four-way switching valve, three-way Switching valve, cooling / heating switching valve (switching mechanism)
23 Heat source side heat exchanger 24 Accumulator 27 Outdoor fan (fan)
27a DC fan motor (DC motor)
41, 51 User side expansion valve (User side expansion mechanism)
42,52 User side heat exchanger

Claims (7)

A heat source unit (2, 102) having a compressor (21) and a heat source side heat exchanger (23) capable of varying the operating capacity, a use side expansion mechanism (41, 51), and a use side heat exchanger (42, 52). ) and a plurality of utilization units (4, 5) with said including a heat source unit and the liquid refrigerant communication pipe that connects the utilization unit (6) and the gas refrigerant communication pipe (7), the heat source-side heat exchanger As a condenser for refrigerant compressed in the compressor, and a refrigerant capable of performing at least a cooling operation in which the use side heat exchanger functions as an evaporator for refrigerant condensed in the heat source side heat exchanger. A circuit (10, 110);
An accumulator (24) connected to the suction side of the compressor and capable of accumulating surplus refrigerant generated in the refrigerant circuit in accordance with the operating load of the utilization unit;
Normal operation mode and, the degree of superheat of the refrigerant at the outlet of the utilization unit and all cooling operation wherein the utilization side heat exchanger for controlling the respective devices of the heat source unit and the utilization unit in accordance with the operating load of the utilization unit A refrigerant amount determination operation mode for controlling the operation capacity of the compressor so that the evaporating pressure of the refrigerant in the use side heat exchanger is constant while controlling each use side expansion mechanism so that the value is positive. It is possible to switch and operate,
In the refrigerant quantity determination operation mode, the refrigerant state is detected by detecting the degree of refrigerant subcooling at the outlet of the heat source side heat exchanger or the fluctuation in the degree of supercooling, and the refrigerant circuit is filled. It is possible to determine the suitability of the amount of refrigerant
Air conditioner (1, 101). The air conditioner ( 1 , 101) according to claim 1 , wherein the operation in the refrigerant quantity determination operation mode is performed periodically. The air conditioner (1, 101) according to claim 1 or 2 , wherein the operation in the refrigerant quantity determination operation mode is performed when the refrigerant is filled in the refrigerant circuit (10, 110). The refrigerant circuit (10, 110) is in a cooling operation state in the normal operation mode, and the use side heat exchanger (42, 52) is a condenser for refrigerant compressed in the compressor (21), and A switching mechanism (22, 122, 71, 81) that enables switching between a heating operation state in which the heat source side heat exchanger (23) functions as an evaporator of refrigerant condensed in the use side heat exchanger. In addition,
In the cooling operation state, the use side expansion mechanism (41, 51) controls the use side heat exchanger so that the degree of superheat of the refrigerant at the outlet of the use side heat exchanger functioning as an evaporator becomes a predetermined value. The refrigerant that controls the flow rate of the flowing refrigerant and flows in the use side heat exchanger so that the degree of supercooling of the refrigerant at the outlet of the use side heat exchanger functioning as a condenser becomes a predetermined value in the heating operation state. To control the flow rate of
The air conditioning apparatus (1, 101) according to any one of claims 1 to 3 . The air conditioner (1, 101) according to any one of claims 1 to 4, wherein the compressor (21) is driven by a motor (21a) controlled by an inverter. The heat source unit (2, 102) further includes a blower fan (27) for blowing air as a heat source to the heat source side heat exchanger (23),
The blower fan can control a flow rate of air supplied to the heat source side heat exchanger so that a condensation pressure of the refrigerant in the heat source side heat exchanger becomes a predetermined value in the refrigerant amount determination operation mode. Is,
The air conditioner (1, 101) according to any one of claims 1 to 5 . The air conditioner (1, 101) according to claim 6 , wherein the blower fan (27) is driven by a DC motor (27a).

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