JP2008175444A - Air conditioner - Google Patents

Abstract

An air conditioner capable of accurately determining a refrigerant amount by stabilizing a condensing pressure even when the outdoor temperature during a refrigerant amount determination operation changes.
An outdoor temperature sensor detects an outdoor temperature Ta. The outdoor fan 28 sends outdoor air to the outdoor heat exchanger 23 that functions as a condenser. The control unit 8 performs PI control of the outdoor fan 28 while changing the gain according to the outdoor temperature Ta. In this PI control, the discharge pressure Pd from the compressor 21 is adjusted so as to continue stably for a predetermined time, and the refrigerant quantity in the refrigerant circuit 10 is determined using the state quantity of the refrigerant flowing through the refrigerant circuit 10.
[Selection] Figure 1

Description

  The present invention relates to a function of determining the suitability of the amount of refrigerant in a refrigerant circuit of an air conditioner, and in particular, a refrigerant circuit of an air conditioner configured by connecting a compressor, a condenser, an expansion mechanism, and an evaporator. It relates to the function of determining the amount of refrigerant in the inside.

Conventionally, in a refrigeration apparatus having a refrigerant circuit configured by connecting a compressor, a condenser, an expansion valve, and an evaporator, a refrigerant amount determination operation is performed to determine whether the refrigerant amount in the refrigerant circuit is excessive or insufficient. A method of determining whether the refrigerant amount in the refrigerant circuit is excessive or insufficient has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 3-186170

  In the above-described method for determining the excess or deficiency of the refrigerant amount in the refrigerant circuit, the refrigerant circuit is divided into a plurality of parts and a refrigerant amount is calculated for each divided part during the refrigerant quantity judgment operation. The amount of refrigerant in the refrigerant circuit is calculated.

  In this case, the amount of refrigerant in each part of each divided refrigerant circuit is calculated by a predetermined relational expression based on the state of the refrigerant, the operating state of the constituent devices, etc. The more accurate the amount of refrigerant can be calculated as the state of the refrigerant and the operating state of the component equipment become more stable.

  Here, for example, when calculating the refrigerant amount around the outdoor heat exchanger that functions as a refrigerant condenser, it is possible to calculate a more accurate refrigerant amount by maintaining the condensation pressure constant. Become.

  However, this condensing pressure is affected by the temperature of the air supplied from the outdoor fan to the outdoor heat exchanger (outdoor temperature), and may not be stable. In such a case, the refrigerant quantity determination operation cannot be performed stably, and as a result, there arises a problem that a determination error in the refrigerant quantity determination becomes large.

  An object of the present invention is to provide an air conditioner capable of determining an accurate refrigerant amount by stabilizing the condensation pressure even when the outdoor temperature during the refrigerant amount determination operation changes. .

  An air conditioner according to a first aspect of the present invention includes a refrigerant circuit, an outdoor temperature detection unit, a blower mechanism, a blower control unit, and a refrigerant amount determination unit. The refrigerant circuit is configured by connecting a compressor, a condenser, an expansion mechanism, and an evaporator. The outdoor temperature detecting means detects the temperature of the outdoor air. The blower mechanism sends outdoor air to the condenser. The air blowing control unit controls the air blowing mechanism while changing the gain according to at least the outdoor temperature detected by the outdoor temperature detecting unit. In this control, the pressure of the refrigerant sent from the compressor to the condenser or the operation state quantity equivalent to the refrigerant pressure is adjusted so as to satisfy a predetermined stabilization condition. The refrigerant quantity determination means determines the refrigerant quantity in the refrigerant circuit using the refrigerant flowing through the refrigerant circuit or the operation state quantity of the component device when the predetermined stabilization condition is satisfied. Here, the control by the air blow control means includes feedback control, and includes, for example, P (proportional) control, PI (proportional integral) control, PID (proportional integral derivative) control, and the like. Moreover, the control of a ventilation control means should just perform control according to the outdoor air temperature at least, for example, may also be control according to indoor temperature further.

  In the conventional constant gain control, when the outside air temperature is low, the gain of the blower mechanism becomes high and hunting occurs, or when the outside air temperature is high, the gain of the blower mechanism becomes low and the refrigerant circuit is stabilized. May be difficult.

  In contrast, here, even if the outside air temperature changes, the air blowing control means changes the gain according to the outdoor temperature to control the air blowing mechanism. For this reason, the ventilation control means can control the refrigerant circuit so that the predetermined stabilization condition is satisfied, so that the condensation pressure can be stabilized, and the refrigerant amount determination means for the stabilized refrigerant circuit is the refrigerant quantity. Can be determined.

  As a result, even when the outside air temperature changes, control is performed to stabilize the condensing pressure in a shorter time and suppress hunting, and the determination accuracy is improved by determining the refrigerant amount for a stable refrigerant circuit. It becomes possible.

  An air conditioner according to a second aspect of the present invention is the air conditioner according to the first aspect of the present invention, further comprising pressure acquisition means for acquiring the pressure of the refrigerant sent from the compressor to the condenser or an operation state quantity equivalent to the pressure of the refrigerant. ing. The predetermined stabilization condition is that the value acquired by the pressure acquisition unit maintains a state where the predetermined pressure range is satisfied for a predetermined time.

  Here, the value acquired by the pressure acquisition unit is controlled by the air blowing control unit so as to maintain a state satisfying a predetermined pressure range for a predetermined time.

  Thereby, it is possible to sufficiently stabilize the refrigerant circuit by suppressing the overshoot of the condensation pressure.

  An air conditioner according to a third aspect of the present invention is the air conditioner according to the first aspect or the second aspect of the present invention, further comprising room temperature detecting means for detecting the temperature of the room air. The air blowing control unit controls the air blowing mechanism while changing the gain according to the outdoor air temperature detected by the outdoor temperature detecting unit and the indoor temperature detected by the indoor temperature detecting unit.

  If the room temperature changes during the control by the air blowing control means, and the pressure on the low pressure side in the refrigerant circuit changes, the pressure on the high pressure side of the refrigerant circuit may change.

  On the other hand, here, not only the change in the outdoor temperature but also the change in the indoor temperature, the air blowing control means changes the gain.

  As a result, it is possible to suppress high pressure instability due to a change in room temperature.

  In the first aspect of the invention, even when the outside air temperature changes, the control for suppressing the hunting by stabilizing the condensation pressure in a shorter time is performed, and the determination accuracy is improved by determining the amount of refrigerant for a stable refrigerant circuit. It becomes possible to improve.

  In the second invention, it is possible to sufficiently stabilize the refrigerant circuit by suppressing the overshoot of the condensation pressure.

  In the third aspect of the invention, it is possible to suppress high pressure instability caused by a change in room temperature.

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

<Indoor unit>
The indoor units 4 and 5 are installed by being embedded or suspended in a ceiling of a room such as a building, or by wall hanging on a wall surface of the room. The indoor units 4 and 5 are connected to the outdoor 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 indoor units 4 and 5 will be described. In addition, since the indoor unit 4 and the indoor unit 5 have the same configuration, only the configuration of the indoor unit 4 will be described here, and the configuration of the indoor unit 5 is the 40th number indicating each part of the indoor unit 4. The reference numerals in the 50s are attached instead of the reference numerals, and description of each part is omitted.

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

  In the present embodiment, the indoor expansion valve 41 is an electric expansion valve connected to 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 10a.

  In the present embodiment, the indoor 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 indoor unit 4 sucks indoor air into the unit, exchanges heat with the refrigerant in the indoor heat exchanger 42, and then supplies the indoor fan 43 as a blower fan to be supplied indoors as supply air. have. The indoor fan 43 is a fan capable of changing the air volume Wr of air supplied to the indoor heat exchanger 42. In this embodiment, the indoor fan 43 is a centrifugal fan or a multiblade fan driven by a motor 43a composed of a DC fan motor. Etc.

  The indoor unit 4 is provided with various sensors. On the liquid side of the indoor heat exchanger 42, a liquid side temperature sensor 44 that detects the temperature of the refrigerant (that is, the refrigerant temperature corresponding to the condensation temperature Tc during the heating operation or the evaporation temperature Te during the cooling operation) is provided. Yes. A gas side temperature sensor 45 that detects the temperature Teo of the refrigerant is provided on the gas side of the indoor heat exchanger 42. An indoor temperature sensor 46 that detects the temperature of indoor air flowing into the unit (that is, the indoor temperature Tr) is provided on the indoor air inlet side of the indoor unit 4. In this embodiment, the liquid side temperature sensor 44, the gas side temperature sensor 45, and the room temperature sensor 46 are thermistors. The indoor unit 4 also has an indoor control unit 47 that controls the operation of each part constituting the indoor unit 4. And the indoor side control part 47 has the microcomputer, memory, etc. which were provided in order to control the indoor unit 4, and is with the remote control (not shown) for operating the indoor unit 4 separately. Control signals and the like can be exchanged between them, and control signals and the like can be exchanged with the outdoor unit 2 via the transmission line 8a.

<Outdoor unit>
The outdoor unit 2 is installed outside a building or the like, and is connected to the indoor units 4 and 5 via the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7. A refrigerant circuit is connected between the indoor units 4 and 5. 10 is constituted.

  Next, the configuration of the outdoor unit 2 will be described. 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 switching valve 22, an outdoor heat exchanger 23 as a heat source side heat exchanger, an outdoor expansion valve 38 as an expansion mechanism, an accumulator 24, It has a supercooler 25 as a temperature adjusting mechanism, a liquid side closing valve 26, and a gas side closing valve 27.

  The compressor 21 is a compressor whose operating capacity can be varied. In the present embodiment, the compressor 21 is a positive displacement compressor driven by a motor 21a whose rotation speed Rm is 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 two or more compressors may be connected in parallel according to the number of indoor units connected.

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

  In the present embodiment, the outdoor 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 outdoor heat exchanger 23 has a gas side connected to the four-way switching valve 22 and a liquid side connected to the liquid refrigerant communication pipe 6. The outdoor heat exchanger 23 has an ability to be determined according to the volume, the surface area including the fin portion, and the like. The capacity of the outdoor heat exchanger 23 is reflected in the calculation as a predetermined coefficient in condensing pressure control, which will be described later, in relation to the wind speed determined by the rotational speed of the motor 28a of the outdoor fan 28.

  In the present embodiment, the outdoor expansion valve 38 is an electric expansion valve connected to the liquid side of the outdoor heat exchanger 23 in order to adjust the pressure and flow rate of the refrigerant flowing in the outdoor refrigerant circuit 10c.

  In the present embodiment, the outdoor unit 2 has an outdoor fan 28 as a blower fan for sucking outdoor air into the unit, exchanging heat with the refrigerant in the outdoor heat exchanger 23, and then discharging the air outside. ing. The outdoor fan 28 is a fan capable of changing the air volume Wo of the air supplied to the outdoor heat exchanger 23. In the present embodiment, the outdoor fan 28 is a propeller fan or the like driven by a motor 28a formed of a DC fan motor. . The motor 28a is connected to the control unit 8 described later, and the wind speed Wo formed by the outdoor fan 28 is adjusted by performing PI control with variable gain.

  The accumulator 24 is connected between the four-way selector valve 22 and the compressor 21 and can accumulate surplus refrigerant generated in the refrigerant circuit 10 in accordance with fluctuations in the operating load of the indoor units 4 and 5. It is a container.

  In this embodiment, the subcooler 25 is a double-pipe heat exchanger, and is provided to cool the refrigerant sent to the indoor expansion valves 41 and 51 after being condensed in the outdoor heat exchanger 23. ing. In the present embodiment, the subcooler 25 is connected between the outdoor expansion valve 38 and the liquid side closing valve 26.

  In the present embodiment, a bypass refrigerant circuit 61 as a cooling source for the subcooler 25 is provided. In the following description, a portion obtained by removing the bypass refrigerant circuit 61 from the refrigerant circuit 10 will be referred to as a main refrigerant circuit for convenience.

  The bypass refrigerant circuit 61 is connected to the main refrigerant circuit so that a part of the refrigerant sent from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 is branched from the main refrigerant circuit and returned to the suction side of the compressor 21. Yes. Specifically, the bypass refrigerant circuit 61 branches a part of the refrigerant sent from the outdoor expansion valve 38 to the indoor expansion valves 41 and 51 from a position between the outdoor heat exchanger 23 and the subcooler 25. It has a branch circuit 61a connected, and a merging circuit 61b connected to the suction side of the compressor 21 so as to return from the outlet on the bypass refrigerant circuit side of the subcooler 25 to the suction side of the compressor 21. The branch circuit 61 a is provided with a bypass expansion valve 62 for adjusting the flow rate of the refrigerant flowing through the bypass refrigerant circuit 61. Here, the bypass expansion valve 62 is an electric expansion valve. Thereby, the refrigerant sent from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 is cooled by the refrigerant flowing in the bypass refrigerant circuit 61 after being depressurized by the bypass expansion valve 62 in the supercooler 25. That is, the capacity control of the subcooler 25 is performed by adjusting the opening degree of the bypass expansion valve 62.

  The liquid side shutoff valve 26 and the gas side shutoff valve 27 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 26 is connected to the outdoor heat exchanger 23. The gas side closing valve 27 is connected to the four-way switching valve 22.

  The outdoor unit 2 is provided with various sensors. Specifically, the outdoor unit 2 includes a suction pressure sensor 29 that detects the suction pressure Ps of the compressor 21, a discharge pressure sensor 30 that detects the discharge pressure Pd of the compressor 21, and a suction temperature Ts of the compressor 21. And a discharge temperature sensor 32 for detecting the discharge temperature Td of the compressor 21 are provided. The suction temperature sensor 31 is provided at a position between the accumulator 24 and the compressor 21. The outdoor heat exchanger 23 has a heat exchange temperature sensor that detects the temperature of the refrigerant flowing in the outdoor heat exchanger 23 (that is, the refrigerant temperature corresponding to the condensation temperature Tc during the cooling operation or the evaporation temperature Te during the heating operation). 33 is provided. On the liquid side of the outdoor heat exchanger 23, a liquid side temperature sensor 34 for detecting the temperature Tco of the refrigerant is provided. A liquid pipe temperature sensor 35 for detecting the temperature of the refrigerant (that is, the liquid pipe temperature Tlp) is provided at the outlet of the subcooler 25 on the main refrigerant circuit side. The junction circuit 61b of the bypass refrigerant circuit 61 is provided with a bypass temperature sensor 63 for detecting the temperature of the refrigerant flowing through the outlet of the subcooler 25 on the bypass refrigerant circuit side. An outdoor temperature sensor 36 for detecting the temperature of the outdoor air flowing into the unit (that is, the outdoor temperature Ta) is provided on the outdoor air inlet side of the outdoor unit 2. In the present embodiment, the suction temperature sensor 31, the discharge temperature sensor 32, the heat exchange temperature sensor 33, the liquid side temperature sensor 34, the liquid pipe temperature sensor 35, the outdoor temperature sensor 36, and the bypass temperature sensor 63 are composed of thermistors. The outdoor unit 2 also has an outdoor control unit 37 that controls the operation of each unit constituting the outdoor unit 2. The outdoor control unit 37 includes a microcomputer provided for controlling the outdoor unit 2, a memory, an inverter circuit for controlling the motor 21a, and the like. Control signals and the like can be exchanged with 47 and 57 via the transmission line 8a. That is, the control part 8 which performs operation control of the whole air conditioning apparatus 1 is comprised by the indoor side control parts 47 and 57, the outdoor side control part 37, and the transmission line 8a which connects between the control parts 37, 47 and 57. Yes.

  As shown in FIG. 2, the control unit 8 is connected so as to receive detection signals of various sensors 29 to 36, 44 to 46, 54 to 56 and 63, and based on these detection signals and the like. And various devices and valves 21, 22, 24, 28 a, 38, 41, 43 a, 51, 53 a, 62 are connected. The control unit 8 is connected to a warning display unit 9 including an LED or the like for notifying that a refrigerant leak has been detected in the refrigerant leak detection operation described later. Here, FIG. 2 is a control block diagram of the air conditioner 1.

<Refrigerant communication piping>
Refrigerant communication pipes 6 and 7 are refrigerant pipes constructed on site when the air conditioner 1 is installed at an installation location such as a building, and installation conditions such as the installation location and a combination of an outdoor unit and an indoor unit. Those having various lengths and tube diameters are used. Therefore, for example, when installing a new air conditioner, it is necessary to accurately grasp information such as the length and diameter of the refrigerant communication pipes 6 and 7 in order to calculate the refrigerant charge amount. The information management and the calculation of the refrigerant amount are complicated. In addition, when the indoor unit or the outdoor unit is updated using the existing pipe, information such as the length and the pipe diameter of the refrigerant communication pipes 6 and 7 may be lost.

  As described above, the refrigerant circuit 10 of the air conditioner 1 is configured by connecting the indoor refrigerant circuits 10a and 10b, the outdoor refrigerant circuit 10c, and the refrigerant communication pipes 6 and 7. In other words, the refrigerant circuit 10 is composed of a bypass refrigerant circuit 61 and a main refrigerant circuit excluding the bypass refrigerant circuit 61. The air conditioner 1 of the present embodiment is operated by switching the cooling operation and the heating operation by the four-way switching valve 22 by the control unit 8 including the indoor side control units 47 and 57 and the outdoor side control unit 37. In addition, the devices of the outdoor unit 2 and the indoor units 4 and 5 are controlled according to the operation load of the indoor units 4 and 5.

(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 the components of the outdoor unit 2 and the indoor units 4 and 5 according to the operation load of the indoor units 4 and 5, and an air conditioner After installation of the component 1 (specifically, not limited to after the initial installation of the device, for example, after remodeling such as adding or removing a component such as an indoor unit, or after repairing a device failure) ) And a refrigerant leakage detection operation mode for determining whether or not refrigerant leaks from the refrigerant circuit 10 after the trial operation is finished and the normal operation is started. The normal operation mode mainly includes a cooling operation for cooling the room and a heating operation for heating the room. Further, the test operation mode mainly includes an automatic refrigerant charging operation for charging the refrigerant into the refrigerant circuit 10, a pipe volume determination operation for detecting the volume of the refrigerant communication pipes 6 and 7, and after installing the constituent devices or the refrigerant circuit. And an initial refrigerant quantity detection operation for detecting the initial refrigerant quantity after the refrigerant is filled therein.

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

<Normal operation mode>
(Cooling operation)
First, the cooling operation in the normal operation mode will be described with reference to FIGS. 1 and 2.

  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 outdoor heat exchanger 23 and the suction side of the compressor 21 is the gas side. It is in a state of being connected to the gas side of the indoor heat exchangers 42 and 52 via the closing valve 27 and the gas refrigerant communication pipe 7. The outdoor expansion valve 38 is fully opened. The liquid side closing valve 26 and the gas side closing valve 27 are in an open state. Each of the indoor expansion valves 41 and 51 is configured such that the superheat degree SHr of the refrigerant at the outlets of the indoor heat exchangers 42 and 52 (that is, the gas side of the indoor heat exchangers 42 and 52) is constant at the superheat degree target value SHrs. The opening is adjusted. In the present embodiment, the superheat degree SHr of the refrigerant at the outlets of the indoor heat exchangers 42 and 52 is detected by the liquid side temperature sensors 44 and 54 from the refrigerant temperature value detected by the gas side temperature sensors 45 and 55. It is detected by subtracting the temperature value (corresponding to the evaporation temperature Te) or the suction pressure Ps of the compressor 21 detected by the suction pressure sensor 29 is converted into a saturation temperature value corresponding to the evaporation temperature Te, and the gas This is detected by subtracting the saturation temperature value of the refrigerant from the refrigerant temperature value detected by the side temperature sensors 45 and 55. Although not adopted in the present embodiment, a temperature sensor that detects the temperature of the refrigerant flowing in each of the indoor heat exchangers 42 and 52 is provided, and the refrigerant temperature corresponding to the evaporation temperature Te detected by the temperature sensor. The superheat degree SHr of the refrigerant at the outlets of the indoor heat exchangers 42 and 52 may be detected by subtracting the value from the refrigerant temperature value detected by the gas side temperature sensors 45 and 55. The opening of the bypass expansion valve 62 is adjusted so that the superheat degree SHb of the refrigerant at the bypass refrigerant circuit side outlet of the supercooler 25 becomes the superheat degree target value SHbs. In the present embodiment, the superheat degree SHb of the refrigerant at the outlet of the subcooler 25 on the bypass refrigerant circuit side is obtained by setting the suction pressure Ps of the compressor 21 detected by the suction pressure sensor 29 to a saturation temperature value corresponding to the evaporation temperature Te. It is detected by converting and subtracting the saturation temperature value of the refrigerant from the refrigerant temperature value detected by the bypass temperature sensor 63. Although not employed in the present embodiment, a temperature sensor is provided at the inlet of the subcooler 25 on the bypass refrigerant circuit side, and the refrigerant temperature value detected by the temperature sensor is detected by the bypass temperature sensor 63. You may make it detect the superheat degree SHb of the refrigerant | coolant in the exit by the side of the bypass refrigerant circuit of the subcooler 25 by subtracting from a temperature value.

  When the compressor 21, the outdoor fan 28, and the indoor fans 43 and 53 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 outdoor heat exchanger 23 via the four-way switching valve 22, exchanges heat with the outdoor air supplied by the outdoor fan 28, and condenses to form a high-pressure liquid refrigerant. Become. The high-pressure liquid refrigerant passes through the outdoor expansion valve 38, flows into the supercooler 25, and is further cooled by exchanging heat with the refrigerant flowing through the bypass refrigerant circuit 61 to be in a supercooled state. At this time, a part of the high-pressure liquid refrigerant condensed in the outdoor heat exchanger 23 is branched to the bypass refrigerant circuit 61, decompressed by the bypass expansion valve 62, and then returned to the suction side of the compressor 21. Here, a part of the refrigerant passing through the bypass expansion valve 62 is evaporated by being depressurized to near the suction pressure Ps of the compressor 21. And the refrigerant | coolant which flows toward the suction | inhalation side of the compressor 21 from the exit of the bypass expansion valve 62 of the bypass refrigerant circuit 61 passes the subcooler 25, and the indoor unit 4 from the outdoor heat exchanger 23 by the side of a main refrigerant circuit. 5 and heat exchange with the high-pressure liquid refrigerant sent to 5.

  Then, the high-pressure liquid refrigerant in a supercooled state is sent to the indoor units 4 and 5 via the liquid-side closing valve 26 and the liquid refrigerant communication pipe 6. The high-pressure liquid refrigerant sent to the indoor units 4 and 5 is depressurized to the vicinity of the suction pressure Ps of the compressor 21 by the indoor expansion valves 41 and 51, and becomes a low-pressure gas-liquid two-phase refrigerant, thereby exchanging the indoor heat. The heat is exchanged with the indoor air in the indoor heat exchangers 42 and 52 and evaporated to become a low-pressure gas refrigerant.

  This low-pressure gas refrigerant is sent to the outdoor unit 2 via the gas refrigerant communication pipe 7 and flows into the accumulator 24 via the gas-side closing valve 27 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.

(Heating operation)
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 indoor heat exchangers 42, 52 via the gas side closing valve 27 and the gas refrigerant communication pipe 7. It is connected to the gas side, and the suction side of the compressor 21 is connected to the gas side of the outdoor heat exchanger 23. The opening of the outdoor expansion valve 38 is adjusted in order to reduce the refrigerant flowing into the outdoor heat exchanger 23 to a pressure at which the refrigerant can be evaporated in the outdoor heat exchanger 23 (that is, the evaporation pressure Pe). Yes. Moreover, the liquid side closing valve 26 and the gas side closing valve 27 are opened. The opening degree of the indoor expansion valves 41 and 51 is adjusted so that the supercooling degree SCr of the refrigerant at the outlets of the indoor heat exchangers 42 and 52 becomes constant at the supercooling degree target value SCrs. In the present embodiment, the refrigerant supercooling degree SCr at the outlets of the indoor heat exchangers 42 and 52 is converted from the discharge pressure Pd of the compressor 21 detected by the discharge pressure sensor 30 to a saturation temperature value corresponding to the condensation temperature Tc. The refrigerant temperature value is detected by subtracting the refrigerant temperature value detected by the liquid side temperature sensors 44 and 54 from the saturation temperature value of the refrigerant. Although not adopted in this embodiment, a temperature sensor that detects the temperature of the refrigerant flowing in each of the indoor heat exchangers 42 and 52 is provided, and the refrigerant temperature corresponding to the condensation temperature Tc detected by this temperature sensor. The supercooling degree SCr of the refrigerant at the outlets of the indoor heat exchangers 42 and 52 may be detected by subtracting the value from the refrigerant temperature value detected by the liquid side temperature sensors 44 and 54. The bypass expansion valve 62 is closed.

  When the compressor 21, the outdoor fan 28, and the indoor fans 43, 53 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. It is sent to the indoor units 4 and 5 via the valve 22, the gas side closing valve 27 and the gas refrigerant communication pipe 7.

  The high-pressure gas refrigerant sent to the indoor units 4 and 5 is condensed by exchanging heat with the indoor air in the outdoor heat exchangers 42 and 52 to become a high-pressure liquid refrigerant, and then the indoor expansion valve 41. , 51, the pressure is reduced according to the valve opening degree of the indoor expansion valves 41, 51.

  The refrigerant that has passed through the indoor expansion valves 41 and 51 is sent to the outdoor unit 2 via the liquid refrigerant communication pipe 6, and further reduced in pressure via the liquid side closing valve 26, the subcooler 25, and the outdoor expansion valve 38. Then, it flows into the outdoor heat exchanger 23. The low-pressure gas-liquid two-phase refrigerant flowing into the outdoor heat exchanger 23 exchanges heat with the outdoor air supplied by the outdoor fan 28 to evaporate into a low-pressure gas refrigerant. And flows into the accumulator 24. Then, the low-pressure gas refrigerant that has flowed into the accumulator 24 is again sucked into the compressor 21.

  Operation control in the normal operation mode as described above is performed by the control unit 8 (more specifically, the indoor side control units 47 and 57 and the outdoor side functioning as normal operation control means for performing normal operation including cooling operation and heating operation. This is performed by the transmission line 8a) connecting the control unit 37 and the control units 37, 47, 57.

<Trial run mode>
Next, the trial operation mode will be described with reference to FIGS. Here, FIG. 3 is a flowchart of the test operation mode. In the present embodiment, in the test operation mode, first, the refrigerant automatic charging operation in step S1 is performed, then the pipe volume determination operation in step S2 is performed, and further, the initial refrigerant amount detection operation in step S3 is performed.

  In the present embodiment, the outdoor unit 2 preliminarily filled with the refrigerant and the indoor units 4 and 5 are installed at an installation location such as a building and connected via the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7. An example will be described in which after the circuit 10 is configured, the refrigerant circuit 10 is additionally filled with a refrigerant that is insufficient in accordance with the volumes of the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7.

(Step S1: Refrigerant automatic charging operation)
First, the liquid side shut-off valve 26 and the gas side shut-off valve 27 of the outdoor unit 2 are opened to fill the refrigerant circuit 10 with the refrigerant that has been filled in the outdoor unit 2 in advance.

  Next, an operator who performs a trial operation connects a refrigerant cylinder for additional charging to a service port (not shown) of the refrigerant circuit 10 and remotely connects to the control unit 8 directly or through a remote controller (not shown). When a command to start a trial run is issued from step S4, the control unit 8 performs steps S11 to S13 shown in FIG. Here, FIG. 4 is a flowchart of the automatic refrigerant charging operation.

(Step S11: refrigerant quantity determination operation)
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 outdoor unit 2 is shown by a solid line in FIG. 51 and the outdoor expansion valve 38 are opened, the compressor 21, the outdoor fan 28, and the indoor fans 43, 53 are activated, and all the indoor units 4, 5 are forcibly cooled (hereinafter referred to as indoor unit total operation). Is performed).

  Then, as shown in FIG. 5, in the refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged by the compressor 21 is flown from the compressor 21 to the outdoor heat exchanger 23 that functions as a condenser. 5 (refer to the portion from the compressor 21 to the outdoor heat exchanger 23 in the hatched portion in FIG. 5), the outdoor heat exchanger 23 functioning as a condenser is liquidated from the gas state by heat exchange with outdoor air. The high-pressure refrigerant that changes in phase flows (refer to the portion corresponding to the outdoor heat exchanger 23 in the hatched and black hatched portions in FIG. 5), from the outdoor heat exchanger 23 to the indoor expansion valve 41, High pressure liquid refrigerant is provided in the flow path including the outdoor expansion valve 38 up to 51, the main refrigerant circuit side portion of the subcooler 25 and the liquid refrigerant communication pipe 6 and the flow path from the outdoor heat exchanger 23 to the bypass expansion valve 62. Flows ( 5) (see the portions from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 and the bypass expansion valve 62 in the black hatched portions of 5), the indoor heat exchangers 42 and 52 functioning as an evaporator, and supercooling Low-pressure refrigerant that changes phase from a gas-liquid two-phase state to a gas state due to heat exchange with room air flows through the portion on the bypass refrigerant circuit side of the chamber 25 (lattice hatched and hatched portions in FIG. 5) Among them, refer to the indoor heat exchangers 42 and 52 and the supercooler 25), the flow path including the gas refrigerant communication pipe 7 and the accumulator 24 from the indoor heat exchangers 42 and 52 to the compressor 21 and the supercooling. The low-pressure gas refrigerant flows through the flow path from the bypass refrigerant circuit side portion of the compressor 25 to the compressor 21 (from the indoor heat exchangers 42 and 52 to the compressor in the hatched portion in FIG. 5). See the section up to the compressor 21 from the portion and the portion of the bypass refrigerant circuit side of the subcooler 25 to 1). FIG. 5 is a schematic diagram illustrating the state of the refrigerant flowing in the refrigerant circuit 10 in the refrigerant quantity determination operation (illustration of the four-way switching valve 22 and the like is omitted).

  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 indoor expansion valves 41 and 51 are controlled so that the superheat degree SHr of the indoor heat exchangers 42 and 52 functioning as an evaporator becomes constant (hereinafter referred to as superheat degree control), and the evaporation pressure Pe is The operating capacity of the compressor 21 is controlled so as to be constant (hereinafter referred to as evaporation pressure control), and the outdoor heat exchanger is configured to be constant by the outdoor fan so that the refrigerant condensing pressure Pc in the outdoor heat exchanger is constant. 23 is controlled (hereinafter referred to as condensing pressure control), and the supercooler 25 is controlled so that the temperature of the refrigerant sent from the supercooler 25 to the indoor expansion valves 41 and 51 is constant. Of the indoor heat exchangers 42 and 52 by the indoor fans 43 and 53 so that the evaporation pressure Pe of the refrigerant is stably controlled by the above-described evaporation pressure control. Indoors supplied to It has the care of the air flow rate Wr constant.

  Here, the evaporating pressure is controlled by the low-pressure refrigerant in the indoor heat exchangers 42 and 52 functioning as an evaporator while changing phase from a gas-liquid two-phase state to a gas state by heat exchange with room air. Refrigerant in the flowing indoor heat exchangers 42 and 52 (refer to the portion corresponding to the indoor heat exchangers 42 and 52 in the lattice-shaped hatched and hatched portions in FIG. 5, hereinafter referred to as the evaporator section C). This is because the amount greatly affects the evaporation pressure Pe of the refrigerant. And here, by controlling the operating capacity of the compressor 21 by the motor 21a whose rotation speed Rm is controlled by the inverter, the refrigerant evaporating pressure Pe in the indoor heat exchangers 42 and 52 is made constant, and the evaporator section The state of the refrigerant flowing in C is stabilized, and a state in which the amount of refrigerant in the evaporator C changes mainly by the evaporation pressure Pe is created. In the control of the evaporation pressure Pe by the compressor 21 of the present embodiment, the refrigerant temperature value (corresponding to the evaporation temperature Te) detected by the liquid side temperature sensors 44 and 54 of the indoor heat exchangers 42 and 52 is used as the saturation pressure. The operating capacity of the compressor 21 is controlled so that this pressure value becomes constant at the low pressure target value Pes (that is, control for changing the rotational speed Rm of the motor 21a) is performed so that the refrigerant becomes a refrigerant. This is realized by increasing or decreasing the refrigerant circulation amount Wc flowing in the circuit 10. Although not adopted in the present embodiment, the compressor 21 detected by the suction pressure sensor 29, which is an operation state quantity equivalent to the refrigerant pressure at the refrigerant evaporation pressure Pe in the indoor heat exchangers 42 and 52, is detected. The compressor 21 is set so that the suction pressure Ps becomes constant at the low pressure target value Pes, or the saturation temperature value (corresponding to the evaporation temperature Te) corresponding to the suction pressure Ps becomes constant at the low pressure target value Tes. The refrigerant temperature value (corresponding to the evaporation temperature Te) detected by the liquid side temperature sensors 44 and 54 of the indoor heat exchangers 42 and 52 becomes constant at the low pressure target value Tes. As such, the operating capacity of the compressor 21 may be controlled.

  And by performing such evaporation pressure control, in the refrigerant | coolant piping containing the gas refrigerant | coolant communication piping 7 and the accumulator 24 from the indoor heat exchangers 42 and 52 to the compressor 21 (in the hatching part of the hatching of FIG. 5) The state of the refrigerant flowing through the indoor heat exchangers 42 and 52 to the compressor 21 (hereinafter referred to as the gas refrigerant circulation portion D) is also stable and is mainly equivalent to the refrigerant pressure in the gas refrigerant circulation portion D. A state in which the amount of refrigerant in the gas refrigerant circulation portion D is changed by the evaporation pressure Pe (that is, the suction pressure Ps), which is a simple operation state amount.

  Condensation pressure control is performed in the outdoor heat exchanger 23 in which a high-pressure refrigerant flows while changing phase from a gas state to a liquid state by heat exchange with outdoor air (hatched hatched and black hatched in FIG. 5). This is because the amount of the refrigerant in the portion corresponding to the outdoor heat exchanger 23 (hereinafter referred to as the condenser part A) greatly affects the refrigerant condensation pressure Pc. And since the condensation pressure Pc of the refrigerant | coolant in this condenser part A changes largely from the influence of outdoor temperature Ta, it controls air volume Wo of the outdoor air supplied to the outdoor heat exchanger 23 from the outdoor fan 28 by the motor 28a. Thus, the refrigerant condensing pressure Pc in the outdoor heat exchanger 23 is made constant, the state of the refrigerant flowing in the condenser part A is stabilized, and mainly the liquid side of the outdoor heat exchanger 23 (hereinafter referred to as refrigerant amount determination operation). In the description, the state in which the amount of refrigerant in the condenser A changes is created by the degree of supercooling SCo in the outlet of the outdoor heat exchanger 23). In the control of the condensation pressure Pc by the outdoor fan 28 of the present embodiment, the compressor 21 detected by the discharge pressure sensor 30, which is an operation state quantity equivalent to the refrigerant condensation pressure Pc in the outdoor heat exchanger 23. The discharge pressure Pd or the temperature of the refrigerant flowing through the outdoor heat exchanger 23 detected by the heat exchange temperature sensor 33 (that is, the condensation temperature Tc) is used.

  Specifically, the control of the condensing pressure Pc by the outdoor fan 28 is performed, for example, by the control unit 8 performing PI control using the discharge pressure Pd as an input value, and using the output value obtained, the motor 28a of the outdoor fan 28 is controlled. This is realized by controlling the rotation speed. Instead of the discharge pressure Pd here, the condensation temperature Tc may be used as described above.

  Further, here, the control unit 8 performs control so as to vary the gain, which is a ratio for amplifying the input value, that is, vary the proportional gain Kp and the integral gain Ki in the PI control to obtain an output value.

  Here, as a comparative example, FIG. 6 shows a conventional PI control with a constant gain. Conventionally, since the gain remains constant when the outside air temperature is high, the gain for causing the outdoor heat exchanger 23 to function as a refrigerant condenser is not sufficient, and the high pressure target value is set. It takes time to approach and stabilize. Further, since the gain remains constant even when the outside air temperature is low, the gain for causing the outdoor heat exchanger 23 to function as a refrigerant condenser is too high, and the high pressure target value It is difficult to stabilize the distribution of the refrigerant in the refrigerant circuit 10 due to the hunting of the condensation pressure around.

  On the other hand, FIG. 7 shows the state of the gain variable PI control described above. Here, since the control unit 8 performs the PI control in which the gain is varied in accordance with the outside air temperature Ta and the room temperature Tr, the occurrence of hunting is suppressed and the refrigerant of the refrigerant circuit 10 is reduced in a shorter time than in the past. Distribution can be stabilized. Specifically, in the PI control of the outdoor fan 28, the control unit 8 determines the difference between the outdoor temperature Ta and the temperature of the refrigerant flowing in the outdoor heat exchanger 23 (that is, the condensation temperature Tc), the air-side heat transfer coefficient (outdoor The proportional gain Kp and the integral gain Ki are adjusted on the basis of the refrigerant heat transfer coefficient, the thickness of the outdoor heat exchanger 23, and the like. The adjustment here is, for example, the condensation of refrigerant when the air volume Wo of the outdoor air supplied from the outdoor fan 28 to the outdoor heat exchanger 23 is changed stepwise by changing the rotation speed of the motor 28a. The gain under each condition is calculated from the response (step response) such as the temperature Tc, the difference between the outdoor temperature Ta and the temperature of the refrigerant flowing in the outdoor heat exchanger 23 (that is, the condensation temperature Tc), the air-side heat transfer The proportional gain Kp and the integral gain Ki may be adjusted by obtaining functions such as the rate, the refrigerant heat transfer coefficient, and the thickness of the outdoor heat exchanger 23. If the installation conditions are such that they can be handled, the control logic may be simplified by ignoring the integral gain Ki and controlling only the proportional gain Kp. By adjusting the proportional gain Kp and the integral gain Ki in this way, excessive PI control can be suppressed and the condensation pressure Pd can be kept stable and constant even in an environment where the outside air temperature Ta changes. Become.

  Further, here, when the room temperature Tr detected by the room temperature sensors 46 and 56 is equal to or lower than a predetermined temperature, the control unit 8 controls the room temperature Tr to be included in the input value in the PI control. Here, the input value may be a value obtained from a polynomial expression of the discharge pressure Pd and the room temperature Tr, for example. Thereby, in the refrigerant determination operation, when the cooling cycle is performed, the indoor temperature Tr and the evaporation temperature detected by the liquid side temperature sensor 44 of the indoor heat exchangers 42 and 52 due to the indoor temperature Tr being too low. It can be avoided that the pressure drop on the low-pressure side of the refrigerant circuit 10 causes a pressure drop on the high-pressure side of the refrigerant circuit 10 due to the insufficient heat exchange amount due to the difference with Te becoming small. .

  Then, by performing such condensation pressure control, the outdoor expansion valve 38 from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51, the portion on the main refrigerant circuit side of the subcooler 25, and the liquid refrigerant communication pipe 6 are connected. The high-pressure liquid refrigerant flows through the flow path including the outdoor heat exchanger 23 and the flow path from the outdoor heat exchanger 23 to the bypass expansion valve 62 of the bypass refrigerant circuit 61, and the indoor expansion valves 41 and 51 and the bypass expansion valve from the outdoor heat exchanger 23. The refrigerant pressure in the portion up to 62 (refer to the black hatched portion in FIG. 5, hereinafter referred to as the liquid refrigerant circulation portion B) is also stabilized by suppressing the occurrence of hunting, and the liquid refrigerant circulation portion B is sealed with the liquid refrigerant. To be in a stable state.

  The liquid pipe temperature control is performed in the refrigerant pipe including the liquid refrigerant communication pipe 6 extending from the subcooler 25 to the indoor expansion valves 41 and 51 (the subcooler in the liquid refrigerant circulation part B shown in FIG. 5). This is to prevent the refrigerant density from changing from 25 to the indoor expansion valves 41 and 51). In the capacity control of the subcooler 25, the refrigerant temperature Tlp detected by the liquid pipe temperature sensor 35 provided at the outlet of the main refrigerant circuit of the subcooler 25 is constant at the liquid pipe temperature target value Tlps. As described above, the flow rate of the refrigerant flowing through the bypass refrigerant circuit 61 is increased and decreased to adjust the amount of heat exchanged between the refrigerant flowing through the main refrigerant circuit side of the subcooler 25 and the refrigerant flowing through the bypass refrigerant circuit side. Yes. The flow rate of the refrigerant flowing through the bypass refrigerant circuit 61 is increased or decreased by adjusting the opening degree of the bypass expansion valve 62. In this manner, liquid pipe temperature control is realized in which the refrigerant temperature in the refrigerant pipe including the liquid refrigerant communication pipe 6 extending from the supercooler 25 to the indoor expansion valves 41 and 51 is constant.

  Then, by performing such liquid tube temperature constant control, the refrigerant amount in the refrigerant circuit 10 gradually increases as the refrigerant circuit 10 is filled with the refrigerant, and at the outlet of the outdoor heat exchanger 23. Even when the refrigerant temperature Tco (that is, the degree of refrigerant supercooling SCo at the outlet of the outdoor heat exchanger 23) changes, the influence of the change in the refrigerant temperature Tco at the outlet of the outdoor heat exchanger 23 The refrigerant piping from the outlet of the heat exchanger 23 to the supercooler 25 only fits in the refrigerant piping from the subcooler 25 to the indoor expansion valves 41 and 51 including the liquid refrigerant communication piping 6 in the liquid refrigerant circulation section B. It will not be affected.

  Further, the superheat control is performed because the amount of refrigerant in the evaporator section C greatly affects the dryness of the refrigerant at the outlets of the indoor heat exchangers 42 and 52. The degree of superheat SHr of the refrigerant at the outlets of the indoor heat exchangers 42 and 52 is controlled by controlling the opening degree of the indoor expansion valves 41 and 51, whereby the gas side of the indoor heat exchangers 42 and 52 (hereinafter referred to as refrigerant amount determination operation). In the description, the refrigerant superheat degree SHr in the indoor heat exchangers 42 and 52 is made constant at the superheat degree target value SHrs (that is, the gas refrigerant at the outlets of the indoor heat exchangers 42 and 52 is used). The state of the refrigerant flowing in the evaporator section C is stabilized.

  And the state which a gas refrigerant | coolant flows reliably to the gas refrigerant | coolant communication part D is created by performing such superheat degree control.

  By the various controls described above, the state of the refrigerant circulating in the refrigerant circuit 10 is stabilized, and the distribution of the refrigerant amount in the refrigerant circuit 10 is constant (the refrigerant state is stable and the distribution of the refrigerant amount is constant). In order to continue the various controls until the predetermined time can be passed while maintaining the state, the refrigerant in the refrigerant circuit 10 is started when the refrigerant circuit 10 starts to be charged by the subsequent additional charging of the refrigerant. It is possible to create a state in which the change in the amount appears mainly as a change in the amount of refrigerant in the outdoor heat exchanger 23 (hereinafter, this operation is referred to as a refrigerant amount determination operation).

  Here, the evaporating pressure Pe (the suction pressure Ps of the compressor 21) is an operating state quantity that depends on the indoor temperature Tr and the outdoor temperature Ta, and therefore, for example, when the temperature is high in summer (hereinafter referred to as the high temperature period). The low-pressure target value Pes that enables stable refrigerant quantity determination operation is applicable and stable in the case of intermediate temperatures such as spring and autumn (hereinafter referred to as the intermediate period). However, even if it is intended to be applied when the temperature is low such as in winter (hereinafter referred to as a low temperature period), a stable refrigerant amount determination operation is performed at such a high evaporation pressure Pe. Can't do it.

  Therefore, in the present embodiment, a plurality of low pressure target values Pes (here, two of the low pressure target value Pesa for low temperature and the low pressure target value Pesb for high temperature) for the evaporation pressure control in the refrigerant amount determination operation are prepared and controlled in advance. This is stored in the memory of the outdoor control unit 37 constituting the unit 8. Then, as shown in FIG. 8, these two low pressure target values Pesa and Pesb are selected according to the conditions of the indoor temperature Tr and / or the outdoor temperature Ta in step S11 (step S14). To S18).

  Specifically, first, in step S14, the indoor temperature Tr in the refrigerant amount determination operation is lower than the low temperature side threshold Tr1 (that is, Tr <Tr1), and the outdoor temperature Ta in the refrigerant amount determination operation is the low temperature side threshold Ta1. If the condition is lower (that is, Ta <Ta1), and if this condition is satisfied, the process proceeds to step S15 to set the low pressure target value Pes to a value suitable for the low temperature period (here Then, the low pressure target value Pesa) for low temperature is selected. On the other hand, when the condition in step S14 is not satisfied, the process proceeds to step S16.

  Next, in step S16, the indoor temperature Tr in the refrigerant amount determination operation is higher than the high temperature side threshold Tr2 (that is, Tr> Tr2), and the outdoor temperature Ta in the refrigerant amount determination operation is higher than the high temperature side threshold Ta2 ( That is, it is determined whether or not Ta <Ta2), and when this condition is satisfied, the process proceeds to step S17, and the low pressure target value Pes is a value suitable for the high temperature period (here, for high temperature) The low pressure target value Pesb) is selected. On the other hand, when the condition in step S16 is not satisfied, the process proceeds to step S18, and the low pressure target value Pes is a value suitable for the intermediate period (here, the low pressure target value Pesa for low temperature and the low pressure target value Pesb for high temperature). Whichever is set as the initial value) is selected.

  Next, in step S19, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the low pressure target value Pes set in steps S15, S17, and S18 (specifically, the low temperature target low pressure target value Pesa and Device control including evaporation pressure control using either one of the high temperature low pressure target value Pesb) is performed.

  Specific conditions and processing for selecting the low temperature target value Pesa for low temperature and the low pressure target value Pesb for high temperature according to the conditions of the indoor temperature Tr and / or the outdoor temperature Ta are not limited to the above-described conditions and processing. For example, other conditions and processing may be used, such as selecting only the condition of the indoor temperature Tr or the condition of only the outdoor temperature Ta.

  The above control and the like are performed by the control unit 8 (more specifically, the indoor side control units 47 and 57, the outdoor side control unit 37, and the control unit 37 functioning as a refrigerant amount determination operation control unit that performs the refrigerant amount determination operation. , 47, 57 are performed as a process of step S11 by the transmission line 8a), and in this step S11, the control unit 8 as the condition changing means performs the conditions of the indoor temperature Tr and / or the outdoor temperature Ta. Accordingly, the processes of steps S14 to S18 in which the low pressure target value Pes is set as a condition relating to the refrigerant quantity determination operation are performed.

  Note that, unlike the present embodiment, when the outdoor unit 2 is not filled with a refrigerant in advance, the constituent devices are abnormally stopped when performing the above-described refrigerant amount determination operation prior to the processing of step S11. It is necessary to charge the refrigerant until the amount of the refrigerant is low.

(Step S12: Calculation of refrigerant amount)
Next, while performing the refrigerant amount determination operation, the refrigerant circuit 10 is additionally charged with the refrigerant. At this time, the control unit 8 functioning as the refrigerant amount calculating means performs additional refrigerant charging in step S12. The refrigerant amount in the refrigerant circuit 10 is calculated from the refrigerant flowing through the refrigerant circuit 10 or the operating state quantity of the component equipment.

  First, the refrigerant quantity calculating means in this embodiment will be described. The refrigerant quantity calculating means calculates the refrigerant quantity in the refrigerant circuit 10 by dividing the refrigerant circuit 10 into a plurality of parts and calculating the refrigerant quantity for each of the divided parts. More specifically, for each divided part, a relational expression between the refrigerant amount of each part and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is set, and these relational expressions are used. The amount of refrigerant in each part can be calculated. And in this embodiment, the refrigerant circuit 10 is the state in which the four-way switching valve 22 is 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 outdoor heat exchanger 23, and In a state where the suction side of the compressor 21 is connected to the outlets of the indoor heat exchangers 42 and 52 via the gas side closing valve 27 and the gas refrigerant communication pipe 7, the compressor 21 and the four-way switching valve from the compressor 21 are connected. 22 (not shown in FIG. 5) up to the outdoor heat exchanger 23 (hereinafter referred to as high pressure gas pipe section E), the outdoor heat exchanger 23 section (that is, the condenser section A), liquid In the refrigerant circulation part B, the part from the outdoor heat exchanger 23 to the supercooler 25 and the inlet side half of the part on the main refrigerant circuit side of the supercooler 25 (hereinafter referred to as the high temperature side liquid pipe part B1), the liquid Out of the part of the refrigerant circulation section B on the main refrigerant circuit side of the subcooler 25. A portion from the side half and the subcooler 25 to the liquid side shut-off valve 26 (not shown in FIG. 5) (hereinafter referred to as a low temperature side liquid pipe portion B2) and the liquid refrigerant communication pipe 6 in the liquid refrigerant circulation portion B (Hereinafter referred to as liquid refrigerant communication pipe section B3) and liquid refrigerant communication pipe 6 from liquid refrigerant communication pipe B to indoor expansion valves 41 and 51 and indoor heat exchangers 42 and 52 (that is, an evaporator). Part C) of the gas refrigerant circulation part D up to the gas refrigerant communication pipe 7 (hereinafter referred to as an indoor unit part F) and part of the gas refrigerant circulation part D of the gas refrigerant communication pipe 7 (hereinafter referred to as gas). A refrigerant communication pipe part G), and a part (hereinafter referred to as the refrigerant connection pipe part G) from the gas side closing valve 27 (not shown in FIG. 5) to the compressor 21 including the four-way switching valve 22 and the accumulator 24. The low-pressure gas pipe part H) and the liquid refrigerant circulation part B Each part is divided into a part (hereinafter referred to as bypass circuit part I) from the liquid pipe part B1 to the low pressure gas pipe part H including the bypass refrigerant circuit side part of the bypass expansion valve 62 and the subcooler 25. A relational expression is set for. Next, the relational expressions set for each part will be described.

In the present embodiment, the relational expression between the refrigerant amount Mog1 in the high-pressure gas pipe part E and the operating state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,
Mog1 = Vog1 × ρd
This is expressed as a functional expression obtained by multiplying the volume Vog1 of the high-pressure gas pipe E of the outdoor unit 2 by the refrigerant density ρd in the high-pressure gas pipe E. The volume Vog1 of the high-pressure gas pipe E is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance. Moreover, the density ρd of the refrigerant in the high-pressure gas pipe E can be obtained by converting the discharge temperature Td and the discharge pressure Pd.

The relational expression between the refrigerant amount Mc in the condenser part A and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mc = kc1 * Ta + kc2 * Tc + kc3 * SHm + kc4 * Wc
+ Kc5 × ρc + kc6 × ρco + kc7
Functional expressions of the outdoor temperature Ta, the condensation temperature Tc, the compressor discharge superheat degree SHm, the refrigerant circulation amount Wc, the saturated liquid density ρc of the refrigerant in the outdoor heat exchanger 23, and the refrigerant density ρco at the outlet of the outdoor heat exchanger 23 Represented as: The parameters kc1 to kc7 in the above relational expression are obtained by regression analysis of the results of tests and detailed simulations, and are stored in the memory of the control unit 8 in advance. The compressor discharge superheat degree SHm is the superheat degree of the refrigerant on the discharge side of the compressor, and the discharge pressure Pd is converted into the saturation temperature value of the refrigerant, and the saturation temperature value of the refrigerant is subtracted from the discharge temperature Td. can get. The refrigerant circulation amount Wc is expressed as a function of the evaporation temperature Te and the condensation temperature Tc (that is, Wc = f (Te, Tc)). The saturated liquid density ρc of the refrigerant is obtained by converting the condensation temperature Tc. The refrigerant density ρco at the outlet of the outdoor heat exchanger 23 is obtained by converting the condensation pressure Pc obtained by converting the condensation temperature Tc and the refrigerant temperature Tco.

The relational expression between the refrigerant amount Mol1 in the high-temperature liquid pipe part B1 and the operation state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,
Mol1 = Vol1 × ρco
The volume Vol1 of the high-temperature liquid pipe part B1 of the outdoor unit 2 is expressed as a function formula obtained by multiplying the refrigerant density ρco in the high-temperature liquid pipe part B1 (that is, the refrigerant density at the outlet of the outdoor heat exchanger 23). The The volume Vol1 of the high-pressure liquid pipe part B1 is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance.

The relational expression between the refrigerant amount Mol2 in the low-temperature liquid pipe part B2 and the operation state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mol2 = Vol2 × ρlp
This is expressed as a functional expression obtained by multiplying the volume Vol2 of the low-temperature liquid pipe portion B2 of the outdoor unit 2 by the refrigerant density ρlp in the low-temperature liquid pipe portion B2. The volume Vol2 of the cryogenic liquid pipe part B2 is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance. The refrigerant density ρlp in the low-temperature liquid pipe portion B2 is the density of the refrigerant at the outlet of the supercooler 25, and is obtained by converting the condensation pressure Pc and the refrigerant temperature Tlp at the outlet of the supercooler 25.

The relational expression between the refrigerant amount Mlp in the liquid refrigerant communication pipe part B3 and the operation state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,
Mlp = Vlp × ρlp
This is expressed as a functional equation obtained by multiplying the volume Vlp of the liquid refrigerant communication pipe 6 by the refrigerant density ρlp in the liquid refrigerant communication pipe section B3 (that is, the refrigerant density at the outlet of the subcooler 25). Note that the volume Vlp of the liquid refrigerant communication pipe 6 is a refrigerant pipe that is constructed on-site when the liquid refrigerant communication pipe 6 is installed at an installation location such as a building. From this information, the value calculated in the field is input, information such as length and pipe diameter is input in the field, and the controller 8 calculates the information from the input information of the liquid refrigerant communication pipe 6, or described later. As described above, the calculation is performed using the operation result of the pipe volume determination operation.

The relational expression between the refrigerant quantity Mr in the indoor unit part F and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mr = kr1 × Tlp + kr2 × ΔT + kr3 × SHr + kr4 × Wr + kr5
The refrigerant temperature Tlp at the outlet of the supercooler 25, the temperature difference ΔT obtained by subtracting the evaporation temperature Te from the indoor temperature Tr, the superheat degree SHr of the refrigerant at the outlet of the indoor heat exchangers 42 and 52, and the indoor fans 43 and 53 It is expressed as a function expression of the air volume Wr. The parameters kr1 to kr5 in the above relational expression are obtained by regression analysis of the results of tests and detailed simulations, and are stored in the memory of the control unit 8 in advance. Here, a relational expression of the refrigerant amount Mr is set corresponding to each of the two indoor units 4 and 5, and the refrigerant amount Mr of the indoor unit 4 and the refrigerant amount Mr of the indoor unit 5 are added. Thus, the total refrigerant amount in the indoor unit portion F is calculated. When the models and capacities of the indoor unit 4 and the indoor unit 5 are different, relational expressions having different values of the parameters kr1 to kr5 are used.

The relational expression between the refrigerant amount Mgp in the gas refrigerant communication pipe part G and the operation state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,
Mgp = Vgp × ρgp
This is expressed as a functional expression obtained by multiplying the volume Vgp of the gas refrigerant communication pipe 7 by the refrigerant density ρgp in the gas refrigerant communication pipe portion H. The volume Vgp of the gas refrigerant communication pipe 7 is similar to the liquid refrigerant communication pipe 6 and is a refrigerant pipe that is constructed on site when the gas refrigerant communication pipe 7 installs the air conditioner 1 at an installation location such as a building. Therefore, it is possible to input a value calculated in the field from information such as length and pipe diameter, or to input information such as length and pipe diameter in the field, and from the input information of the gas refrigerant communication pipe 7, the control unit 8 or using the operation result of the pipe volume determination operation as will be described later. In addition, the refrigerant density ρgp in the gas refrigerant pipe connection portion G is equal to the refrigerant density ρs on the suction side of the compressor 21 and the refrigerant at the outlets of the indoor heat exchangers 42 and 52 (that is, the inlet of the gas refrigerant communication pipe 7). It is an average value with density ρeo. The refrigerant density ρs is obtained by converting the suction pressure Ps and the suction temperature Ts. The refrigerant density ρeo is the conversion value of the evaporation temperature Te and the outlet temperature Teo of the indoor heat exchangers 42 and 52. Is obtained by converting.

The relational expression between the refrigerant amount Mog2 in the low-pressure gas pipe part H and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mog2 = Vog2 × ρs
This is expressed as a functional expression obtained by multiplying the volume Vog2 of the low-pressure gas pipe H in the outdoor unit 2 by the refrigerant density ρs in the low-pressure gas pipe H. The volume Vog2 of the low-pressure gas pipe H is a known value before being shipped to the installation location, and is stored in the memory of the controller 8 in advance.

The relational expression between the refrigerant amount Mob in the bypass circuit section I and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,
Mob = kob1 × ρco + kob2 × ρs + kob3 × Pe + kob4
The refrigerant density ρco at the outlet of the outdoor heat exchanger 23, the refrigerant density ρs at the outlet of the subcooler 25 on the bypass circuit side, and the evaporation pressure Pe are expressed as functional expressions. The parameters kob1 to kob3 in the above relational expression are obtained by regression analysis of the results of tests and detailed simulations, and are stored in the memory of the control unit 8 in advance. Further, the volume Mob of the bypass circuit portion I may have a smaller refrigerant amount than other parts, and may be calculated by a simple relational expression. For example,
Mob = Vob × ρe × kob5
This is expressed as a functional expression obtained by multiplying the volume Vob of the bypass circuit I by the saturated liquid density ρe and the correction coefficient kob in the bypass circuit side portion of the subcooler 25. The volume Vob of the bypass circuit unit I is a known value before the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control unit 8 in advance. Further, the saturated liquid density ρe in the portion on the bypass circuit side of the subcooler 25 is obtained by converting the suction pressure Ps or the evaporation temperature Te.

  In the present embodiment, the number of outdoor units 2 is one, but when a plurality of outdoor units are connected, the refrigerant amounts Mog1, Mc, Mol1, Mol2, Mog2, and Mob related to the outdoor units A relational expression of the refrigerant amount of each part is set corresponding to each of the units, and the total refrigerant quantity of the outdoor unit is calculated by adding the refrigerant amount of each part of the plurality of outdoor units. . When a plurality of outdoor units having different models and capacities are connected, a relational expression for the refrigerant amount of each part having different parameter values is used.

  As described above, in the present embodiment, the refrigerant amount of each part is calculated from the refrigerant flowing through the refrigerant circuit 10 in the refrigerant quantity determination operation or the operation state quantity of the component device using the relational expression for each part of the refrigerant circuit 10. Thus, the refrigerant amount of the refrigerant circuit 10 can be calculated.

  And since this step S12 is repeated until the conditions of determination of the appropriateness | suitableness of the refrigerant | coolant amount in below-mentioned step S13 are satisfy | filled, it is about each part of the refrigerant circuit 10 until it completes after the additional charge of a refrigerant | coolant is started. Using the relational expression, the amount of refrigerant in each part is calculated from the operating state amount when the refrigerant is charged. More specifically, the refrigerant amount Mo in the outdoor unit 2 and the refrigerant amount Mr in each indoor unit 4, 5 (that is, the refrigerant communication pipes 6 and 7, which are necessary for determining whether or not the refrigerant amount is appropriate in step S 13 described later). The refrigerant amount of each part of the refrigerant circuit 10 excluding the refrigerant circuit 10 is calculated. Here, the refrigerant amount Mo in the outdoor unit 2 is calculated by adding the refrigerant amounts Mog1, Mc, Mol1, Mol2, Mog2, and Mob of each part in the outdoor unit 2 described above.

  In this way, the control unit 8 that functions as the refrigerant amount calculating means for calculating the refrigerant amount of each part of the refrigerant circuit 10 from the refrigerant flowing in the refrigerant circuit 10 in the refrigerant automatic charging operation or the operation state quantity of the component device, performs step S12. Is performed.

(Step S13: Determination of appropriateness of refrigerant amount)
As described above, when additional charging of the refrigerant into the refrigerant circuit 10 is started, the refrigerant amount in the refrigerant circuit 10 gradually increases. Here, when the volume of the refrigerant communication pipes 6 and 7 is unknown, the amount of refrigerant to be charged in the refrigerant circuit 10 after additional charging of the refrigerant cannot be defined as the refrigerant amount of the entire refrigerant circuit 10. . However, if attention is paid only to the outdoor unit 2 and the indoor units 4 and 5 (that is, the refrigerant circuit 10 excluding the refrigerant communication pipes 6 and 7), the optimum amount of refrigerant in the outdoor unit 2 in the normal operation mode is determined by tests and detailed simulations. Since the refrigerant amount is stored in advance in the memory of the control unit 8 as the charging target value Ms, the refrigerant flowing through the refrigerant circuit 10 in the automatic refrigerant charging operation or the configuration using the relational expression described above. Additional refrigerant charging is performed until the refrigerant amount value obtained by adding the refrigerant amount Mo of the outdoor unit 2 and the refrigerant amount Mr of the indoor units 4 and 5 calculated from the operation state amount of the device reaches the charging target value Ms. Will do. That is, step S13 determines whether or not the refrigerant amount value obtained by adding the refrigerant amount Mo of the outdoor unit 2 and the refrigerant amount Mr of the indoor units 4 and 5 in the automatic refrigerant charging operation has reached the charging target value Ms. In this process, the suitability of the amount of refrigerant charged in the refrigerant circuit 10 by additional charging of the refrigerant is determined.

  In step S13, the refrigerant amount value obtained by adding the refrigerant amount Mo of the outdoor unit 2 and the refrigerant amount Mr of the indoor units 4 and 5 is smaller than the charging target value Ms, and additional refrigerant charging is not completed. In step S13, the process in step S13 is repeated until the filling target value Ms is reached. Further, when the refrigerant amount value obtained by adding the refrigerant amount Mo of the outdoor unit 2 and the refrigerant amount Mr of the indoor units 4 and 5 reaches the charging target value Ms, the additional charging of the refrigerant is completed, and automatic refrigerant charging is performed. Step S1 as the operation process is completed.

  In the refrigerant amount determination operation described above, as the additional charging of the refrigerant into the refrigerant circuit 10 proceeds, the degree of supercooling SCo at the outlet of the outdoor heat exchanger 23 tends to increase mainly, resulting in the outdoor heat exchanger. 23, the refrigerant amount Mc increases, and the refrigerant amount in other parts tends to be kept substantially constant. Therefore, the charging target value Ms is set to the refrigerant of the outdoor unit 2 instead of the outdoor unit 2 and the indoor units 4 and 5. It may be set as a value corresponding only to the amount Mo, or may be set as a value corresponding to the refrigerant amount Mc of the outdoor heat exchanger 23, and additional refrigerant charging may be performed until the charging target value Ms is reached. Good.

  As described above, the control unit 8 that functions as a refrigerant amount determination unit that determines the suitability of the refrigerant amount in the refrigerant circuit 10 in the refrigerant amount determination operation of the automatic refrigerant charging operation (that is, whether or not the charging target value Ms has been reached). Step S13 is performed.

(Step S2: Pipe volume judgment operation)
When the automatic refrigerant charging operation in step S1 is completed, the process proceeds to a pipe volume determination operation in step S2. In the pipe volume determination operation, the processing of step S21 to step S25 shown in FIG. Here, FIG. 9 is a flowchart of the pipe volume determination operation.

(Steps S21 and S22: Pipe volume determination operation for liquid refrigerant communication pipe and calculation of volume)
In step S21, the liquid refrigerant communication pipe 6 including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control is performed in the same manner as the refrigerant amount determination operation in step S11 in the above-described automatic refrigerant charging operation. Perform pipe volume judgment operation. Here, the liquid pipe temperature target value Tlps of the refrigerant temperature Tlp at the outlet on the main refrigerant circuit side of the subcooler 25 in the liquid pipe temperature control is set as the first target value Tlps1, and the refrigerant amount determination operation is performed based on the first target value Tlps1. Is the first state (see the refrigeration cycle indicated by the line including the broken line in FIG. 10). FIG. 10 is a Mollier diagram showing the refrigeration cycle of the air-conditioning apparatus 1 in the pipe volume determination operation for the liquid refrigerant communication pipe.

  Next, from the first state in which the refrigerant temperature Tlp at the outlet on the main refrigerant circuit side of the subcooler 25 in the liquid pipe temperature control is stabilized at the first target value Tlps1, other equipment control, that is, condensing pressure control, overheating, is performed. The second condition in which the liquid pipe temperature target value Tlps is different from the first target value Tlps1 without changing the conditions of the degree control and the evaporation pressure control (that is, without changing the superheat degree target value SHrs and the low pressure target value Tes). The second state is changed to the target value Tlps2 and stabilized (see the refrigeration cycle shown by the solid line in FIG. 10). In the present embodiment, the second target value Tlps2 is a temperature higher than the first target value Tlps1.

  Thus, since the density of the refrigerant | coolant in the liquid refrigerant communication piping 6 becomes small by changing from the stable state in the 1st state to the 2nd state, the refrigerant | coolant amount Mlp of the liquid refrigerant communication piping part B3 in a 2nd state Decreases compared to the amount of refrigerant in the first state. And the refrigerant | coolant decreased from this liquid refrigerant communication piping part B3 will move to the other part of the refrigerant circuit 10. FIG. More specifically, as described above, since the conditions for equipment control other than the liquid pipe temperature control are not changed, the refrigerant amount Mog1 in the high-pressure gas pipe E and the refrigerant quantity in the low-pressure gas pipe H The refrigerant amount Mgp in the Mog2 and the gas refrigerant communication pipe part G is kept almost constant, and the refrigerant decreased from the liquid refrigerant communication pipe part B3 is the condenser part A, the high temperature liquid pipe part B1, the low temperature liquid pipe part B2, the room It moves to the unit part F and the bypass circuit part I. That is, the refrigerant amount Mc in the condenser part A, the refrigerant quantity Mol1 in the high temperature liquid pipe part B1, the refrigerant quantity Mol2 in the low temperature liquid pipe part B2, and the indoor unit part F by the amount of the refrigerant reduced from the liquid refrigerant communication pipe part B3. The refrigerant quantity Mr and the refrigerant quantity Mob in the bypass circuit section I increase.

  The above control is performed by the control unit 8 (more specifically, the indoor side control unit) functioning as a pipe volume determination operation control unit that performs a pipe volume determination operation for calculating the volume Mlp of the liquid refrigerant communication pipe unit 6. 47, 57, the outdoor control unit 37, and the transmission line 8a) connecting the control units 37, 47, 57 are performed as the process of step S21.

  Next, in step S22, the change from the first state to the second state makes use of the phenomenon that the refrigerant decreases from the liquid refrigerant communication pipe part B3 and moves to the other part of the refrigerant circuit 10 to make liquid refrigerant communication. The volume Vlp of the pipe 6 is calculated.

First, an arithmetic expression used to calculate the volume Vlp of the liquid refrigerant communication pipe 6 will be described. The amount of refrigerant that has decreased from the liquid refrigerant communication piping part B3 and moved to the other part of the refrigerant circuit 10 by the pipe volume determination operation described above is defined as the refrigerant increase / decrease amount ΔMlp, and the refrigerant in each part between the first and second states. Assuming that the increase / decrease amount of ΔMc, ΔMol1, ΔMol2, ΔMr, and ΔMob (here, the refrigerant amount Mog1, the refrigerant amount Mog2, and the refrigerant amount Mgp are kept almost constant), the refrigerant increase / decrease amount ΔMlp is, for example,
ΔMlp = − (ΔMc + ΔMol1 + ΔMol2 + ΔMr + ΔMob)
It can be calculated from the function expression Then, by dividing the value of ΔMlp by the refrigerant density change Δρlp between the first and second states in the liquid refrigerant communication pipe 6, the volume Vlp of the liquid refrigerant communication pipe 6 can be calculated. Note that, although the calculation result of the refrigerant increase / decrease amount ΔMlp is hardly affected, the refrigerant quantity Mog1 and the refrigerant quantity Mog2 may be included in the above-described function formula.

Vlp = ΔMlp / Δρlp
ΔMc, ΔMol1, ΔMol2, ΔMr, and ΔMob are calculated by calculating the refrigerant amount in the first state and the refrigerant amount in the second state using the relational expressions for the respective parts of the refrigerant circuit 10 described above. The density change amount Δρlp is obtained by subtracting the refrigerant amount in the first state from the refrigerant amount in the state, and the density change amount Δρlp is the refrigerant density at the outlet of the subcooler 25 in the first state and the subcooler 25 in the second state. Is calculated by subtracting the refrigerant density in the first state from the refrigerant density in the second state.

  The volume Vlp of the liquid refrigerant communication pipe 6 can be calculated from the refrigerant flowing through the refrigerant circuit 10 in the first and second states or the operation state quantity of the component equipment using the above arithmetic expression.

  In the present embodiment, the state is changed so that the second target value Tlps2 in the second state is higher than the first target value Tlps1 in the first state, and the refrigerant in the liquid refrigerant communication pipe section B2 is changed to another one. The amount of refrigerant in the other part is increased by moving to the part, and the volume Vlp of the liquid refrigerant communication pipe 6 is calculated from this increased amount. However, the second target value Tlps2 in the second state is in the first state. The state is changed so that the temperature is lower than the first target value Tlps1, and the refrigerant amount in the other part is decreased by moving the refrigerant from the other part to the liquid refrigerant communication pipe part B3. The volume Vlp of the liquid refrigerant communication pipe 6 may be calculated.

  As described above, the pipe volume for the liquid refrigerant communication pipe for calculating the volume Vlp of the liquid refrigerant communication pipe 6 from the refrigerant flowing through the refrigerant circuit 10 in the pipe volume determination operation for the liquid refrigerant communication pipe 6 or the operation state quantity of the component device. The process of step S22 is performed by the control part 8 which functions as a calculation means.

(Steps S23 and S24: Pipe volume determination operation for gas refrigerant communication pipe and calculation of volume)
After the above-described steps S21 and S22 are completed, in step S23, the pipe volume determination operation for the gas refrigerant communication pipe 7 including the indoor unit 100% operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control. I do. Here, the low pressure target value Pes of the suction pressure Ps of the compressor 21 in the evaporation pressure control is set as the first target value Pes1, and the state in which the refrigerant amount determination operation is stabilized at the first target value Pes1 is set as the first state (FIG. (Refer to the refrigeration cycle indicated by the line including eleven dashed lines). FIG. 11 is a Mollier diagram showing the refrigeration cycle of the air conditioner 1 in the pipe volume determination operation for the gas refrigerant communication pipe.

  Next, from the first state where the low pressure target value Pes of the suction pressure Ps of the compressor 21 in the evaporation pressure control is stabilized at the first target value Pes1, other device control, that is, liquid pipe temperature control, condensing pressure control, and overheating. The low pressure target value Pes is changed to the second target value Pes2 that is different from the first target value Pes1 without changing the degree control condition (that is, without changing the liquid pipe temperature target value Tlps and the superheat degree target value SHrs). The second state is changed and stabilized (see the refrigeration cycle shown only by the solid line in FIG. 11). In the present embodiment, the second target value Pes2 is a pressure lower than the first target value Pes1.

  Thus, since the density of the refrigerant in the gas refrigerant communication pipe 7 is reduced by changing from the stable state in the first state to the second state, the refrigerant amount Mgp of the gas refrigerant communication pipe part G in the second state. Decreases compared to the amount of refrigerant in the first state. And the refrigerant | coolant decreased from this gas refrigerant communication piping part G will move to the other part of the refrigerant circuit 10. FIG. More specifically, as described above, the device control conditions other than the evaporation pressure control are not changed, so the refrigerant amount Mog1 in the high-pressure gas pipe part E and the refrigerant quantity Mol1 in the high-temperature liquid pipe part B1. The refrigerant amount Mol2 in the low temperature liquid pipe part B2 and the refrigerant quantity Mlp in the liquid refrigerant communication pipe part B3 are kept substantially constant, and the refrigerant reduced from the gas refrigerant communication pipe part G is the low pressure gas pipe part H, the condenser part. A, it moves to the indoor unit part F and the bypass circuit part I. That is, the refrigerant amount Mog2 in the low-pressure gas pipe part H, the refrigerant quantity Mc in the condenser part A, the refrigerant quantity Mr in the indoor unit part F, and the refrigerant in the bypass circuit part I by the amount of refrigerant reduced from the gas refrigerant communication pipe part G The amount Mob will increase.

  The above control is performed by the control unit 8 (more specifically, the indoor side control unit 47 that functions as a pipe volume determination operation control unit that performs a pipe volume determination operation for calculating the volume Vgp of the gas refrigerant communication pipe 7. 57, the outdoor control unit 37, and the transmission line 8a) connecting the control units 37, 47, and 57, the process is performed in step S23.

  Next, in step S24, the change from the first state to the second state makes use of the phenomenon that the refrigerant decreases from the gas refrigerant communication pipe part G and moves to the other part of the refrigerant circuit 10 to make the gas refrigerant communication. The volume Vgp of the pipe 7 is calculated.

First, an arithmetic expression used for calculating the volume Vgp of the gas refrigerant communication pipe 7 will be described. The amount of refrigerant that has decreased from the gas refrigerant communication piping part G and moved to the other part of the refrigerant circuit 10 by the pipe volume determination operation described above is defined as the refrigerant increase / decrease amount ΔMgp, and the refrigerant in each part between the first and second states. Assuming that the amount of increase / decrease is ΔMc, ΔMog2, ΔMr, and ΔMob (here, the refrigerant amount Mog1, the refrigerant amount Mol1, the refrigerant amount Mol2, and the refrigerant amount Mlp are omitted since they are substantially constant), the refrigerant increase / decrease amount ΔMgp is For example,
ΔMgp = − (ΔMc + ΔMog2 + ΔMr + ΔMob)
It can be calculated from the function expression Then, by dividing the value of ΔMgp by the refrigerant density change Δρgp between the first and second states in the gas refrigerant communication pipe 7, the volume Vgp of the gas refrigerant communication pipe 7 can be calculated. Although the calculation result of the refrigerant increase / decrease amount ΔMgp is hardly affected, the refrigerant quantity Mog1, the refrigerant quantity Mol1, and the refrigerant quantity Mol2 may be included in the above-described functional formula.

Vgp = ΔMgp / Δρgp
ΔMc, ΔMog2, ΔMr, and ΔMob are calculated using the relational expressions for the respective parts of the refrigerant circuit 10 described above to calculate the refrigerant amount in the first state and the refrigerant amount in the second state. The density change amount Δρgp is obtained by subtracting the refrigerant amount in the first state from the refrigerant amount, and the density change amount Δρgp is the refrigerant density ρs on the suction side of the compressor 21 in the first state and the outlets of the indoor heat exchangers 42 and 52. Is calculated by subtracting the average density in the first state from the average density in the second state.

  The volume Vgp of the gas refrigerant communication pipe 7 can be calculated from the refrigerant flowing through the refrigerant circuit 10 in the first and second states or the operation state quantity of the component device using the above arithmetic expression.

  In the present embodiment, the state is changed so that the second target value Pes2 in the second state is lower than the first target value Pes1 in the first state, and the refrigerant in the gas refrigerant communication pipe part G is changed to another The amount of refrigerant in the other part is increased by moving to the part, and the volume Vlp of the gas refrigerant communication pipe 7 is calculated from this increased amount. However, the second target value Pes2 in the second state is in the first state. The state is changed so that the pressure is higher than the first target value Pes1, and the refrigerant amount in the other part is decreased by moving the refrigerant from the other part to the gas refrigerant communication pipe part G. The volume Vlp of the gas refrigerant communication pipe 7 may be calculated.

  In this way, the pipe volume for the gas refrigerant communication pipe that calculates the volume Vgp of the gas refrigerant communication pipe 7 from the refrigerant flowing in the refrigerant circuit 10 in the pipe volume determination operation for the gas refrigerant communication pipe 7 or the operation state quantity of the component equipment. The process of step S24 is performed by the control part 8 which functions as a calculation means.

(Step S25: Determination of the validity of the result of the pipe volume determination operation)
After step S21 to step S24 are completed, in step S25, whether or not the result of the pipe volume determination operation is appropriate, that is, the volume Vlp of the refrigerant communication pipes 6 and 7 calculated by the pipe volume calculation means. , Vgp is determined to be valid.

  Specifically, as in the following inequality, the determination is made based on whether the ratio of the volume Vlp of the liquid refrigerant communication pipe 6 to the volume Vgp of the gas refrigerant communication pipe 7 obtained by the calculation is within a predetermined numerical range.

ε1 <Vlp / Vgp <ε2
Here, ε1 and ε2 are values that are varied based on the minimum value and the maximum value of the pipe volume ratio in a feasible combination of the heat source unit and the utilization unit.

  When the volume ratio Vlp / Vgp satisfies the above numerical range, the processing of step S2 for the pipe volume determination operation is completed. When the volume ratio Vlp / Vgp does not satisfy the above numerical range, The pipe volume determination operation and the volume calculation process in steps S21 to S24 are performed.

  Thus, whether or not the result of the pipe volume determination operation described above is appropriate, that is, whether or not the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 calculated by the pipe volume calculating means are appropriate. The process of step S25 is performed by the control unit 8 functioning as a validity determination unit for determining

  In the present embodiment, the pipe volume determination operation for the liquid refrigerant communication pipe 6 (steps S21 and S22) is performed first, and then the pipe volume determination operation for the gas refrigerant communication pipe 7 (steps S23 and S24). However, the pipe volume determination operation for the gas refrigerant communication pipe 7 may be performed first.

  Moreover, in the above-mentioned step S25, when it is determined a plurality of times that the result of the pipe volume determination operation in steps S21 to S24 is not appropriate, or the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 can be more simply set. When it is desired to make the determination, although not shown in FIG. 8, for example, after it is determined in step S25 that the result of the pipe volume determination operation in steps S21 to S24 is not valid, the refrigerant communication pipes 6 and 7 The pipe length of the refrigerant communication pipes 6 and 7 is estimated from the pressure loss, and the process shifts to a process of calculating the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 from the estimated pipe length and the average volume ratio. The volumes Vlp and Vgp of the pipes 6 and 7 may be obtained.

  Further, in the present embodiment, the pipe volume determination operation is performed on the assumption that there is no information such as the length and pipe diameter of the refrigerant communication pipes 6 and 7 and the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 are unknown. Although the case where the volume Vlp and Vgp of the refrigerant communication pipes 6 and 7 are calculated has been described, the pipe volume calculation means inputs the information such as the length and the diameter of the refrigerant communication pipes 6 and 7 to input the refrigerant communication pipe. In the case of having a function of calculating the volumes Vlp and Vgp of 6 and 7, these functions may be used in combination.

  Furthermore, without using the function of calculating the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 using the above-described pipe volume determination operation and the operation results, information such as the length and diameter of the refrigerant communication pipes 6 and 7 is obtained. When only the function of calculating the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 by using the input is used, the input refrigerant communication pipes 6 and 7 are input using the above-described validity determination means (step S25). It may be determined whether or not the information such as the length and the pipe diameter is appropriate.

(Step S3: Initial refrigerant quantity detection operation)
When the pipe volume determination operation in step S2 is completed, the process proceeds to the initial refrigerant amount determination operation in step S3. In the initial refrigerant quantity detection operation, the control unit 8 performs the processes of step S31 and step S32 shown in FIG. Here, FIG. 12 is a flowchart of the initial refrigerant quantity detection operation.

(Step S31: Refrigerant amount determination operation)
In step S31, similar to the refrigerant amount determination operation in step S11 of the above-described automatic refrigerant charging operation, the refrigerant amount determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control is performed. Done. Here, the liquid pipe temperature target value Tlps in the liquid pipe temperature control, the superheat degree target value SHrs in the superheat degree control, and the low pressure target value Pes in the evaporation pressure control are, in principle, the refrigerant amount determination operation in step S11 of the automatic refrigerant charging operation. The same value as the target value at is used. That is, in the same manner as the refrigerant quantity determination operation in step S11 of the automatic refrigerant charging operation, in step S31, a condition change process (steps S14 to S18 in FIG. 8) for selecting the low pressure target value Pes according to the conditions of the indoor temperature Tr and the outdoor temperature Ta. The low pressure target value Pes (specifically, one of the low temperature low pressure target value Pesa and the high temperature low pressure target value Pesb) is selected as in the automatic refrigerant charging operation. .

  As described above, the control unit 8 functioning as the refrigerant amount determination operation control unit that performs the refrigerant amount determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control, Processing is performed.

(Step S32: Calculation of refrigerant amount)
Next, the refrigerant circuit 10 is calculated from the refrigerant flowing through the refrigerant circuit 10 in the initial refrigerant amount determination operation in step S32 or the operation state amount of the component device by the control unit 8 functioning as the refrigerant amount calculation means while performing the refrigerant amount determination operation described above. The amount of refrigerant in is calculated. The refrigerant amount in the refrigerant circuit 10 is calculated using a relational expression between the refrigerant amount of each part of the refrigerant circuit 10 and the refrigerant flowing through the refrigerant circuit 10 or the operation state quantity of the component device. Since the volume Vlp and Vgp of the refrigerant communication pipes 6 and 7 that have been unknown after the installation of the components of the air conditioner 1 are calculated by the above-described pipe volume determination operation, the refrigerant communication is performed. By multiplying the volumes Vlp and Vgp of the pipes 6 and 7 by the refrigerant density, the refrigerant amounts Mlp and Mgp in the refrigerant communication pipes 6 and 7 are calculated, and further, the refrigerant amounts of the other parts are added, The initial refrigerant amount of the entire refrigerant circuit 10 can be detected. This initial refrigerant amount is used as a reference refrigerant amount Mi for the entire refrigerant circuit 10 that serves as a reference for determining whether or not there is leakage from the refrigerant circuit 10 in the refrigerant leakage detection operation described later. In the memory of the control unit 8 as the state quantity storage means, the time when the initial refrigerant amount detection operation is performed (specifically, the low temperature period, the intermediate period and the high temperature period) or the room temperature Tr during the initial refrigerant amount detection operation And the data of the outdoor temperature Ta.

  In this way, the control unit 8 that functions as the refrigerant amount calculating means for calculating the refrigerant amount of each part of the refrigerant circuit 10 from the refrigerant flowing in the refrigerant circuit 10 in the initial refrigerant amount detection operation or the operation state quantity of the component device, performs the steps. The low pressure target value Pes (that is, one of the low temperature low pressure target value Pesa and the high temperature low pressure target value Pesb) selected according to the conditions of the indoor temperature Tr and the outdoor temperature Ta at the time of the test operation is performed. The initial refrigerant amount as the reference refrigerant amount Mi in the condition is detected.

<Refrigerant leak detection operation mode>
Next, the refrigerant leakage detection operation mode will be described with reference to FIGS. 1, 2, 5, and 13 to 16. Here, FIGS. 13 to 16 are flowcharts of the refrigerant leakage detection operation mode.

  In the present embodiment, when detecting whether or not the refrigerant has leaked from the refrigerant circuit 10 to the outside due to an unforeseen cause on a regular basis (for example, when it is not necessary to perform air conditioning on holidays or late at night). An example will be described.

  First, when the operation in the normal operation mode such as the cooling operation and the heating operation described above has passed for a certain time (for example, every six months to one year), the operation mode is automatically or manually switched from the normal operation mode to the refrigerant leakage detection operation mode. Then, similar to the refrigerant quantity determination operation in the initial refrigerant quantity detection operation, the refrigerant quantity determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control is performed. Here, the liquid pipe temperature target value Tlps in the liquid pipe temperature control, the superheat degree target value SHrs in the superheat degree control, and the low pressure target value Pes in the evaporation pressure control are the initial refrigerant from the viewpoint of the determination accuracy of the presence or absence of refrigerant leakage, which will be described later. It is desirable to use the same value as the target value in step S31 of the refrigerant amount determination operation of the amount detection operation. In particular, as in the present embodiment, a method of calculating the refrigerant amount of the refrigerant circuit 10 using a relational expression between the refrigerant flowing in the refrigerant circuit 10 or the operation state quantity of the component device and the refrigerant quantity of the refrigerant circuit 10 is adopted. In such a case, the determination error becomes large. This is because the parameters constituting the relational expression used in the calculation of the refrigerant amount match the conditions of the specific refrigerant amount determination operation condition or the average refrigerant amount determination operation condition of the test or simulation for obtaining the parameter. For example, under the conditions of each of the plurality of low pressure target values Pes (here, the low pressure target value Pesa for low temperature and the low pressure target value Pesb for high temperature), the refrigerant amount is calculated using the above-described relational expression. This is because even if the calculation is performed, a deviation occurs between the refrigerant amounts at the respective low pressure target values Pes.

  However, since the plurality of low-pressure target values Pes are selected according to the conditions of the indoor temperature Tr and the outdoor temperature Ta during operation, the time when the refrigerant leakage detection operation is performed (specifically, the low temperature period, the intermediate period, and the In reality, the high temperature period) cannot be carried out at the same time as the initial refrigerant amount detection operation described above, and as a result, the operation state in the refrigerant amount determination operation in which the conditions of the low pressure target value Pes are different. The refrigerant amount calculated from the amount and the reference refrigerant amount are compared, and the determination accuracy of the presence or absence of refrigerant leakage may be deteriorated.

  Therefore, in the refrigerant leak detection operation of the present embodiment, the reference refrigerant amount detection operation for detecting the reference refrigerant amount Mi that is a reference for determining whether or not the refrigerant leaks from the refrigerant circuit 10 is performed for each low pressure target value Pes. When calculating the reference refrigerant amount Mi for each low pressure target value Pes and determining the presence or absence of refrigerant leakage from the refrigerant circuit 10, the reference refrigerant amount at the same low pressure target value Pes as the low pressure target value Pes in the refrigerant leakage detection operation Compared with the low pressure target value Pe in the refrigerant leak detection operation, comparing Mi and the refrigerant amount calculated in the refrigerant leak detection operation, or considering a deviation between the reference refrigerant amounts Mi for each low pressure target value Pes The reference refrigerant amount Mi at the low pressure target value Pes is compared. Hereinafter, this process will be described.

(Steps S41 to S45: Selection of low pressure target value according to conditions of indoor temperature and outdoor temperature)
First, as shown in FIG. 13, in steps S41 to S45, the current operation is performed in the low temperature period and the intermediate period according to the conditions of the indoor temperature Tr and the outdoor temperature Ta in the same manner as in the above-described steps S14 to S18. And the high temperature period and the selection of the low pressure target value Pes.

(Steps S46 to 51: Determination of whether or not deviation data is acquired and refrigerant amount determination operation)
Next, as shown in FIG. 14, in step S46, it is determined whether or not the current operation is in the intermediate period. If it is determined that the current operation is in the intermediate period, the process proceeds to step S47. If it is determined that it is not the period, the process proceeds to step S48.

  Next, when the current operation is an intermediate period, the refrigerant quantity determination operation can be stably performed with either the low temperature target value Pesa or the high temperature target value Pesb. The reference refrigerant amount detection operation (steps S59 and S60) is performed to determine whether or not it is necessary to acquire data on the refrigerant amount deviation between the reference refrigerant amounts Mi (step S61). Here, for example, whether or not the deviation data needs to be acquired can be determined based on whether or not the deviation data is stored in the memory of the control unit 8. If the deviation data has already been acquired, it is not necessary to acquire the reference refrigerant amount detection operation and the deviation data, so the process proceeds to the refrigerant amount determination operation of the refrigerant leakage detection operation in step S51, and the initial refrigerant amount Similar to the refrigerant amount determination operation of the detection operation, the refrigerant amount determination operation including the indoor unit total number operation, the condensation pressure control, the liquid pipe temperature control, the superheat degree control, and the evaporation pressure control is performed. However, as the low pressure target value Pes, the low pressure target value Pes selected in steps S41 to S45 described above is used. On the other hand, if the deviation data has not been acquired, the process proceeds to step S49 and is reset to the low pressure target value Pes selected in the initial refrigerant amount detection operation as one of the reference refrigerant amount detection operations. Then, the process proceeds to step S50, and the refrigerant amount determination operation is performed using the low pressure target value Pes selected in the initial refrigerant amount detection operation.

  Next, when the current operation is not an intermediate period, in step S48, it is determined whether the current low pressure target value Pes is the same as the low pressure target value Pes selected in the initial refrigerant amount detection operation, and the deviation. A determination is made whether data needs to be acquired. If the current low-pressure target value Pes is different from the low-pressure target value Pes selected in the initial refrigerant amount detection operation and the deviation data is not acquired, the refrigerant leakage detection operation is performed in the current operation. As a result, there is no comparable reference refrigerant amount Mi or deviation data between the reference refrigerant amounts Mi, and it is impossible to accurately determine whether or not the refrigerant has leaked. However, since the reference refrigerant amount Mi should be acquired, the same processing as the initial refrigerant amount detection operation (that is, steps S62 and S63) is performed, and after acquiring one of the reference refrigerant amounts Mi, the refrigerant Leak detection operation mode ends. On the other hand, when the current low-pressure target value Pes is the same as the low-pressure target value Pes selected in the initial refrigerant amount detection operation or when deviation data is acquired, it is possible to determine the presence or absence of refrigerant leakage. The process proceeds to step S51.

(Steps S52 to S54: Calculation of refrigerant amount and determination of leakage when deviation data has already been acquired)
Next, as shown in FIG. 15, the refrigerant flowing through the refrigerant circuit 10 in the refrigerant leakage detection operation in step S <b> 52 by the control unit 8 that functions as the refrigerant amount calculation unit while performing the refrigerant amount determination operation in step S <b> 51 described above. The refrigerant amount in the refrigerant circuit 10 is calculated from the operation state quantities of the constituent devices. The refrigerant amount in the refrigerant circuit 10 is calculated using a relational expression between the refrigerant amount of each part of the refrigerant circuit 10 and the refrigerant flowing through the refrigerant circuit 10 or the operation state quantity of the component device. Similarly to the initial refrigerant amount determination operation, the above-described pipe volume determination operation calculates the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 that were unknown after the installation of the components of the air conditioner 1 and are known. Therefore, by multiplying the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 by the density of the refrigerant, the refrigerant amounts Mlp and Mgp in the refrigerant communication pipes 6 and 7 are calculated, and each other part The refrigerant amount M of the refrigerant circuit 10 as a whole can be calculated by adding the refrigerant amounts.

  Here, as described above, since the temperature Tlp of the refrigerant in the liquid refrigerant communication pipe 6 is kept constant at the same liquid pipe temperature target value Tlps by the liquid pipe temperature control, the amount of refrigerant in the liquid refrigerant communication pipe portion B3 Mlp is kept constant even when the temperature Tco of the refrigerant at the outlet of the outdoor heat exchanger 23 fluctuates regardless of the operating condition of the refrigerant leak detection operation.

  In this way, the control unit 8 that functions as the refrigerant amount calculating means for calculating the refrigerant amount of each part of the refrigerant circuit 10 from the refrigerant flowing in the refrigerant circuit 10 or the operation state quantity of the component device in the refrigerant leakage detection operation, the step S52. Is performed.

At this time, if the refrigerant leaks from the refrigerant circuit 10 to the outside, the amount of refrigerant in the refrigerant circuit 10 decreases. When the refrigerant quantity in the refrigerant circuit 10 decreases, mainly, appeared a tendency subcooling degree SC _o at the outlet of the outdoor heat exchanger 23 is reduced, Accordingly, the refrigerant quantity Mc in the outdoor heat exchanger 23 is reduced However, the amount of refrigerant in other parts tends to be kept substantially constant. Therefore, the refrigerant amount M of the entire refrigerant circuit 10 calculated in step S52 described above is based on the reference refrigerant amount Mi detected in the initial refrigerant amount detection operation when refrigerant leakage from the refrigerant circuit 10 occurs. When the refrigerant leakage from the refrigerant circuit 10 does not occur, the reference refrigerant amount Mi becomes almost the same value.

  Utilizing this fact, in step S53, it is determined whether or not the refrigerant has leaked. Specifically, the reference refrigerant amount Mi that can be compared with the refrigerant amount at the low pressure target value Pes in the current refrigerant amount determination operation (that is, the reference refrigerant amount Mi acquired at the same low pressure target value Pes) is directly compared, Or the presence or absence of the leakage of a refrigerant | coolant is determined by considering the deviation data between the reference | standard refrigerant | coolant amount Mi for every low-pressure target value Pes, and comparing with the reference | standard refrigerant | coolant amount Mi acquired in different low-pressure target value Pes. If it is determined in step S53 that the refrigerant has not leaked from the refrigerant circuit 10, the refrigerant leak detection operation mode is terminated.

  On the other hand, if it is determined in step S53 that the refrigerant has leaked from the refrigerant circuit 10, the process proceeds to step S54, and a warning notifying that the refrigerant has been detected is displayed on the warning display unit 9. After the display, the refrigerant leak detection operation mode is terminated.

(Steps S56 to S61: Calculation of refrigerant amount, deviation determination, and acquisition of deviation data when deviation data is not acquired)
Next, as shown in FIG. 16, the refrigerant flowing through the refrigerant circuit 10 in the refrigerant leakage detection operation in step S <b> 56 by the control unit 8 that functions as the refrigerant amount calculation means while performing the refrigerant amount determination operation in step S <b> 50 described above. The refrigerant quantity in the refrigerant circuit 10 is calculated from the operation state quantity of the component device in the same manner as in step S52 described above.

  In step S57, the refrigerant amount M in the refrigerant circuit 10 calculated in step S56 is compared with the reference refrigerant amount Mi calculated in the initial refrigerant amount detection operation as one of the reference refrigerant amount detection operations. The presence or absence of refrigerant leakage is determined. As described above, since deviation data is not acquired here, it is not possible to determine the presence or absence of refrigerant leakage by comparing with the reference refrigerant amount Mi acquired at different low-pressure target values Pes. Since the low-pressure target value Pes in the current refrigerant quantity determination operation is the same as the low-pressure target value Pes in the initial refrigerant quantity detection operation, the refrigerant leakage is obtained by directly comparing the calculated refrigerant quantity M with the reference refrigerant quantity Mi. The presence or absence of can be determined. If it is determined in step S57 that the refrigerant has not leaked from the refrigerant circuit 10, the process proceeds to the next step S59. On the other hand, if it is determined in step S57 that the refrigerant has leaked from the refrigerant circuit 10, the process proceeds to step S58 to give a warning to the warning display unit 9 informing that the refrigerant leak has been detected. After the display, the refrigerant leak detection operation mode is terminated.

  Next, in step S59, a reference refrigerant amount detection operation similar to the initial refrigerant amount detection operation is performed. Specifically, the low-pressure target value Pes that is different from the low-pressure target value Pes selected in the above-described steps S49 to S58, for example, the low-pressure target value Pes selected in the initial refrigerant amount detection operation is the high-temperature low-pressure target. In the case of the value Pesb, the reference refrigerant amount Mi when the low pressure target value Pes is the high temperature low pressure target value Pesb is known by the processing of the above-described steps S49 to S58, but in the initial refrigerant amount detection operation. The reference refrigerant amount Mi at the low-pressure target value Pesa for low temperature that is not selected is unknown. Then, if the deviation data between the reference refrigerant amount Mi at the low-temperature low-pressure target value Pesa or the reference refrigerant amount Mi at the high-temperature low-pressure target value Pesb remains unknown, for example, the refrigerant leakage detection operation is attempted in the low temperature period. However, since there is no reference refrigerant amount Mi or deviation data that can be compared with the calculated refrigerant amount M, the presence or absence of refrigerant leakage cannot be determined with high accuracy in the low temperature period.

  Therefore, in step S59, after selecting a low pressure target value Pes that has not been selected in the processing of steps S49 to S58, that is, for which deviation data has not been acquired, the process proceeds to step S60 to perform a refrigerant amount determination operation. In step S61, the refrigerant amount in the refrigerant circuit 10 is calculated, and the deviation from the reference refrigerant amount Mi in the low pressure target value Pes for which no deviation data has been acquired or the reference refrigerant amount Mi in the initial refrigerant amount detection operation. Data is acquired and the refrigerant leakage detection operation mode is terminated. Here, the obtained reference refrigerant amount Mi or deviation data is stored in the memory of the control unit 8 together with the value of the low pressure target value Pes.

  Next, the specific example in the case of performing the refrigerant | coolant leak detection driving | operation in the air conditioning apparatus 1 of this embodiment by the process of above-mentioned step S41-S61 is demonstrated.

  For example, the case where the initial refrigerant leakage detection operation is performed in the high temperature period when the initial refrigerant amount detection operation is performed in the high temperature period (that is, the condition of the high temperature low pressure target value Pesb) will be described. First, it is determined by the processes of steps S41, S43, and S44 that the refrigerant leakage detection operation is in the high temperature period, and the high pressure low pressure target value Pesb is selected as the low pressure target value Pes. Next, the refrigerant amount determination operation of the refrigerant leakage detection operation in the high temperature period (that is, the condition of the high temperature low pressure target value Pesb) is performed by the processes of steps S46, S48, and S51. Next, the presence or absence of the leakage of the refrigerant is determined by the processes of steps S52 and S53, and the refrigerant leakage detection operation mode is ended.

  Then, the second refrigerant leakage detection operation is performed in the intermediate period. Then, first, it is determined that the refrigerant leakage detection operation is in the intermediate period by the processes of steps S41, S43, and S45, and the high-temperature low-pressure target value Pesb is selected as the low-pressure target value Pes. Next, it is determined by the processes of steps S46, S47, S49, and S50 that deviation data needs to be acquired, and the refrigerant amount determination in the refrigerant leakage detection operation in the high temperature period (that is, the condition of the high temperature low pressure target value Pesb). Driving is performed. Next, the presence or absence of the leakage of the refrigerant is determined by the processes of steps S56 and S57, and the process proceeds to the process of the reference refrigerant amount detection operation (steps S59 to S61). Next, the low-pressure target value Pesa for low temperature is selected as the low-pressure target value Pes for which there is no deviation data by the processes of steps S59, S60, and S61, and the refrigerant amount determination operation of the reference refrigerant amount detection operation is performed. After the refrigerant amount Mi or the deviation data is acquired, the refrigerant leakage detection operation mode is terminated.

  And the 3rd refrigerant | coolant leak detection driving | operation is implemented in a low temperature period. Then, first, it is determined by the processes of steps S41 and S42 that the refrigerant leakage detection operation is in the low temperature period, and the low pressure target value Pesa for low temperature is selected as the low pressure target value Pes. Next, the refrigerant amount determination operation of the refrigerant leak detection operation in the low temperature period (that is, the condition of the low temperature low pressure target value Pesa) is performed by the processes of steps S46, S48, and S51. Next, by the processing of steps S52 and S53, the presence or absence of refrigerant leakage is determined using the reference refrigerant amount Mi or deviation data in the low-pressure target value Pesa for low temperature acquired in the second refrigerant leakage detection operation. Leak detection operation mode ends.

  As another specific example, for example, when the initial refrigerant amount detection operation is performed in the high temperature period (that is, the condition of the high temperature low pressure target value Pesb), the first refrigerant leakage detection operation is performed in the intermediate period. Will be described. First, it is determined by the processes of steps S41, S43, and S45 that the refrigerant leakage detection operation is in the intermediate period, and the high-temperature low-pressure target value Pesb is selected as the low-pressure target value Pes. Next, it is determined by the processes of steps S46, S47, S49, and S50 that deviation data needs to be acquired, and the refrigerant amount determination in the refrigerant leakage detection operation in the high temperature period (that is, the condition of the high temperature low pressure target value Pesb). Driving is performed. Next, the presence or absence of the leakage of the refrigerant is determined by the processes of steps S56 and S57, and the process proceeds to the process of the reference refrigerant amount detection operation (steps S59 to S61). Next, the low-pressure target value Pesa for low temperature is selected as the low-pressure target value Pes for which there is no deviation data by the processes of steps S59, S60, and S61, and the refrigerant amount determination operation of the reference refrigerant amount detection operation is performed. After the refrigerant amount Mi or the deviation data is acquired, the refrigerant leakage detection operation mode ends.

  Then, the second refrigerant leakage detection operation is performed in the high temperature period. Then, first, it is determined by the processes of steps S41, S43, and S44 that the refrigerant leakage detection operation is in the high temperature period, and the high pressure low pressure target value Pesb is selected as the low pressure target value Pes. Next, the refrigerant amount determination operation of the refrigerant leakage detection operation in the high temperature period (that is, the condition of the high temperature low pressure target value Pesb) is performed by the processes of steps S46, S48, and S51. Next, the presence or absence of refrigerant leakage is determined by the processing of steps S52 and S53, and the refrigerant leakage detection operation mode ends.

  And the 3rd refrigerant | coolant leak detection driving | operation is implemented in a low temperature period. Then, first, it is determined by the processes of steps S41 and S42 that the refrigerant leakage detection operation is in the low temperature period, and the low pressure target value Pesa for low temperature is selected as the low pressure target value Pes. Next, the refrigerant amount determination operation of the refrigerant leak detection operation in the low temperature period (that is, the condition of the low temperature low pressure target value Pesa) is performed by the processes of steps S46, S48, and S51. Next, the presence or absence of refrigerant leakage is determined by using the reference refrigerant amount Mi or the deviation data in the low-temperature low-pressure target value Pesa acquired in the first refrigerant leakage detection operation by the processing of steps S52 and S53, and the refrigerant Leak detection operation mode ends.

  As described above, by performing the reference refrigerant amount detection operation in the intermediate period, it is possible to acquire the reference refrigerant amount Mi or deviation data for reducing the determination error of the refrigerant leakage due to the difference in the low pressure target value Pes. .

  As described above, in the air conditioner 1 of the present modification, the control unit 8 includes the refrigerant amount determination operation unit, the refrigerant amount calculation unit, the refrigerant amount determination unit, the pipe volume determination operation unit, the pipe volume calculation unit, and the validity determination. By functioning as means, condition change means, relational expression selection means, and state quantity accumulation means, a refrigerant amount determination system for determining the suitability of the refrigerant amount charged in the refrigerant circuit 10 is configured.

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

  In the air conditioner 1 of the present embodiment, by performing the condensation pressure control in the refrigerant amount determination operation or the like, even in an installation situation where the outdoor temperature Ta or the indoor temperature Tr changes, the hunting of the condensation pressure Pd is suppressed and shortened. The state of the refrigerant flowing through the entire refrigerant circuit 10 is stabilized by stabilizing the time.

  For this reason, whether or not the refrigerant amount in the refrigerant circuit 10 has reached the charging target value Mi based on each value of the stabilized refrigerant circuit 10 even in a situation where the outdoor temperature Ta or the indoor temperature Tr changes. The refrigerant amount can be determined with high accuracy, such as detection of the initial refrigerant amount, and leakage of the refrigerant can be detected more accurately. Further, in the above refrigeration cycle, even if the pipe volume of the liquid refrigerant communication pipe 6 or the gas refrigerant communication pipe 7 is unknown, the pipe volume is set using each value of the refrigerant circuit 10 stabilized by the condensation pressure control. Since it can also be determined, the pipe volume can be determined more accurately.

  In any of the high temperature period, the intermediate period, and the low temperature period, the control by the control target value corresponding to each period is performed to suppress the influence of the indoor temperature Tr and the outdoor temperature Ta during the refrigerant amount determination operation, Since the state in which the refrigerant flowing through the refrigerant circuit 10 is stabilized can be realized, the refrigerant amount can be determined with high accuracy at any time, and leakage of the refrigerant can be detected accurately.

(4) Other Embodiments 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. It is.

  For example, in the above-described embodiment, the example in which the present invention is applied to an air conditioner capable of switching between cooling and heating has been described. However, the present invention is not limited to this, and the present invention is applied to other air conditioners such as an air conditioner dedicated to cooling. You may apply. Moreover, although the above-mentioned embodiment demonstrated the example which applied this invention to the air conditioning apparatus provided with the one outdoor unit, it is not limited to this, This air conditioner provided with the several outdoor unit is this. The invention may be applied.

  By using the present invention, the refrigerant amount determination operation can be performed without being affected by the conditions of the indoor temperature and the outdoor temperature during the refrigerant amount determination operation.

It is a schematic block diagram of the air conditioning apparatus concerning one Embodiment of this invention. It is a control block diagram of an air conditioning apparatus. It is a flowchart of test run mode. It is a flowchart of a refrigerant | coolant automatic charging operation. 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 inside of a refrigerant circuit in refrigerant | coolant amount determination driving | operation. It is a graph which shows the mode of PI control of the conventional outdoor fan with constant gain. It is a graph which shows the mode of PI control of the outdoor fan of a gain variable concerning one Embodiment of this invention. It is a flowchart which shows the condition change process in a refrigerant | coolant amount determination driving | operation. It is a flow chart of piping volume judging operation. It is a Mollier diagram which shows the refrigerating cycle of the air conditioning apparatus in the pipe volume determination driving | operation for liquid refrigerant communication pipes. It is a Mollier diagram which shows the refrigerating cycle of the air conditioning apparatus in the pipe volume determination driving | operation for gas refrigerant | coolant connection piping. 3 is a flowchart of an initial refrigerant quantity determination operation. It is a flowchart (process concerning selection of the low pressure target value by the conditions of indoor temperature and outdoor temperature) of a refrigerant | coolant leak detection operation mode. It is a flowchart (process concerning the determination of the presence or absence of acquisition of deviation data, and the refrigerant | coolant amount determination driving | operation as a refrigerant | coolant leakage detection driving | operation) of a refrigerant | coolant leakage detection driving mode. It is a flowchart (process concerning calculation of the refrigerant | coolant amount in case deviation data are already acquired, and determination of the presence or absence of a leak) of refrigerant | coolant leak detection operation mode. It is a flowchart (process concerning calculation of the refrigerant | coolant amount in case deviation data are not acquired, determination of the presence or absence of leakage, and acquisition of deviation data) of a refrigerant | coolant leak detection operation mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 8 Control part 10 Refrigerant circuit 21 Compressor 23 Outdoor heat exchanger (heat source side heat exchanger)
41, 51 Indoor expansion valve (expansion mechanism)
42, 52 Indoor heat exchanger (use side heat exchanger)

Claims (3)

A refrigerant circuit (10) configured by connecting a compressor (21), a condenser (23), an expansion mechanism (41, 51), and an evaporator (42, 52);
Outdoor temperature detecting means (36) for detecting the temperature of the outdoor air;
A blower mechanism (28) for sending outdoor air to the condenser;
The compressor (21) is sent to the condenser (23) by controlling the blower mechanism (28) while changing the gain according to at least the outdoor temperature detected by the outdoor temperature detecting means (36). Air flow control means (37) for adjusting the pressure of the refrigerant to be generated or the operation state quantity equivalent to the pressure of the refrigerant to satisfy a predetermined stabilization condition;
Refrigerant amount determination means (37) for determining the amount of refrigerant in the refrigerant circuit (10) using the refrigerant flowing through the refrigerant circuit (10) or the operating state quantity of the component device when the predetermined stabilization condition is satisfied. )When,
An air conditioner (1) comprising: Pressure acquisition means (30) for acquiring an operating state quantity equivalent to the pressure of the refrigerant sent from the compressor (21) to the condenser (23) or the pressure of the refrigerant;
The predetermined stabilization condition is that a value acquired by the pressure acquisition means (30) maintains a state satisfying a condition of a predetermined pressure range for a predetermined time.
The air conditioner (1) according to claim 1. It further comprises room temperature detecting means (46, 56) for detecting the temperature of the room air,
The air blowing control means (37) changes the gain according to the outdoor air temperature detected by the outdoor temperature detecting means (36) and the indoor temperature detected by the indoor temperature detecting means (46, 56). Controlling the mechanism (28),
The air conditioner (1) according to claim 1 or 2.

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