WO2008013089A1

WO2008013089A1 - Air conditioner

Info

Publication number: WO2008013089A1
Application number: PCT/JP2007/064222
Authority: WO
Inventors: Manabu Yoshimi; Tadafumi Nishimura; Shinichi Kasahara
Original assignee: Daikin Industries, Ltd.
Priority date: 2006-07-24
Filing date: 2007-07-19
Publication date: 2008-01-31
Also published as: JP2008025936A

Abstract

A quantity of a refrigerant dissolved in a refrigeration oil in a compressor is accurately grasped and whether a quantity of the refrigerant in a refrigerant circuit is suitable or not is highly accurately judged. An air conditioner (1) is provided with a refrigerant circuit (10) composed by connecting a compressor (21), an outdoor heat exchanger (23), indoor expansion valves (41, 51) and outdoor heat exchangers (42, 52). The air conditioner is also provided with a refrigerant quantity judging means for judging whether a quantity of a refrigerant in the refrigerant circuit (10) is suitable or not, based on an operation-status quantity of the refrigerant flowing in the refrigerant circuit (10) or that of a constitutive apparatus. The maximum difference between the temperature of the refrigeration oil inside the compressor (21) and that of the refrigerant brought into contact with the refrigeration oil is 50°C or below.

Description

Specification

Air conditioner

Technical field

[0001] The present invention relates to a function for determining the suitability of the amount of refrigerant in the refrigerant circuit of an air conditioner, in particular, by connecting a compressor, a heat source side heat exchanger ^, an expansion mechanism, and a user side heat exchanger. The present invention relates to a function of determining whether or not the amount of refrigerant in a refrigerant circuit of an air conditioner configured is appropriate. Background art

[0002] Conventionally, in order to determine the excess or deficiency of the refrigerant amount in the refrigerant circuit of the air conditioner, there has been a method of simulating refrigeration cycle characteristics and using this calculation result to determine the excess or deficiency of the refrigerant amount. It has been proposed (for example, see Patent Document 1).

Patent Document 1: Japanese Patent Laid-Open No. 2000-304388

Disclosure of the invention

[0003] However, the above-described method for determining the excess or deficiency of the refrigerant amount by the simulation of the refrigeration cycle characteristics requires a huge amount of calculation, and is usually inexpensive such as a microcomputer mounted on the air conditioner. In a computing device, the computation time may be long, or the computation itself may be impossible.

On the other hand, the inventor of the present application uses a relational expression between the refrigerant amount of each part and the operating state quantity of the refrigerant or component equipment flowing through the refrigerant circuit when the refrigerant circuit is divided into a plurality of parts, and A method of calculating the refrigerant amount of each part from the refrigerant flowing through the circuit or the operating state quantity of the component equipment, and using the refrigerant amount of each part obtained by this calculation to determine the suitability of the refrigerant quantity in the refrigerant circuit In this case, the suitability of the refrigerant amount in the refrigerant circuit can be determined with high accuracy while suppressing the calculation load (see # 112005-363732).

[0004] Then, when determining the suitability of the refrigerant amount in the refrigerant circuit using such a method, if the accuracy of judging the suitability of the refrigerant amount is further improved, the amount of refrigerant dissolved in the refrigerating machine oil In particular, it is necessary to ascertain as accurately as possible the amount of refrigerant dissolved in the refrigerating machine oil accumulated in the oil reservoir inside the compressor and reflect it in the calculation of the refrigerant amount. In order to accurately grasp the amount of refrigerant dissolved in the refrigerating machine oil accumulated in such an oil reservoir, the oil reservoir It is necessary to detect the pressure and temperature of the accumulated refrigeration oil and use it to calculate the solubility of the refrigerant in the refrigeration oil.

However, the refrigerating machine oil accumulated in the oil reservoir inside the compressor has a temperature distribution in the refrigerating machine oil due to the temperature of the refrigerant in contact with the refrigerating machine oil and the temperature of the wall of the compressor casing that forms the oil reservoir. It is difficult to detect the exact temperature of the refrigerating machine oil accumulated in the oil reservoir, resulting in a large calculation error in the solubility of the refrigerant in the refrigerating machine oil accumulated in the oil reservoir. In particular, it is not possible to improve the accuracy of determining the appropriateness of the refrigerant amount.

[0005] An object of the present invention is to accurately grasp the amount of refrigerant dissolved in the refrigeration oil inside the compressor, and to determine whether or not the amount of refrigerant in the refrigerant circuit is appropriate.

[0006] An air conditioner according to a first aspect of the present invention includes a refrigerant circuit configured by connecting a compressor, a heat source side heat exchange, an expansion mechanism, and a use side heat exchanger, and a cooling circuit that flows through the refrigerant circuit. Refrigerant amount determination means for determining the suitability of the refrigerant amount in the refrigerant circuit based on the operation state quantity of the medium or the component device, and a temperature difference between the refrigerant oil in the compressor and the refrigerant in contact with the refrigerant oil. The maximum value is 50 ° C or less.

In this air conditioner, the maximum temperature difference between the refrigeration oil inside the compressor and the refrigerant in contact with the refrigeration oil is 50 ° C or less, so the temperature distribution of the refrigeration oil inside the compressor Will occur. As a result, it becomes possible to accurately grasp the amount of refrigerant dissolved in the refrigeration oil inside the compressor, so that the suitability of the amount of refrigerant in the refrigerant circuit can be determined with high accuracy.

[0007] An air conditioner according to a second aspect of the present invention is the air conditioner according to the first aspect of the invention, wherein the compressor has an oil reservoir that can store refrigerating machine oil therein. The refrigerant is in contact with the upper surface of the refrigerating machine oil accumulated in the oil reservoir inside the compressor. In this air conditioner, since the refrigerant is in contact with the oil upper surface of the refrigerating machine oil collected in the oil reservoir, the refrigerating machine oil near the oil upper surface approaches the temperature of the refrigerant, and the compressor casing forms the oil reservoir. The refrigeration oil near the wall of the compressor approaches the wall temperature, that is, the ambient temperature outside the compressor.Therefore, the refrigeration oil accumulated in the oil reservoir has the temperature of the refrigerant in contact with the oil upper surface and the ambient temperature outside the compressor. The temperature distribution corresponding to the temperature difference of It will be closed. In this air conditioner, the temperature difference between the temperature of the refrigerant in contact with the upper surface of the oil and the temperature of the refrigeration oil near the wall of the compressor casing forming the oil reservoir is substantially 50 ° C or less. Therefore, the amount of refrigerant dissolved in the refrigeration oil inside the compressor can be accurately grasped, and the suitability of the amount of refrigerant in the refrigerant circuit can be determined with high accuracy.

[0008] An air conditioner according to a third aspect of the present invention is the air conditioner according to the first or second aspect of the invention, wherein the air conditioner is dissolved in the refrigerating machine oil based on the refrigerant flowing through the refrigerant circuit or the operating state quantity of the component equipment. The apparatus further includes a refrigerant quantity calculating means for calculating the refrigerant quantity in the refrigerant circuit including the dissolved refrigerant quantity that is the refrigerant quantity. The refrigerant amount determining means determines whether the refrigerant amount in the refrigerant circuit is appropriate based on the refrigerant amount calculated by the refrigerant amount calculating means.

In this air conditioner, since the maximum value of the temperature difference between the refrigeration oil inside the compressor and the refrigerant in contact with the refrigeration oil is 50 ° C or less, for example, the refrigerant flowing through the refrigerant circuit or Even when calculating the amount of dissolved refrigerant based on the temperature of the refrigerant in contact with the refrigeration oil inside the compressor as one of the operating state quantities of the component equipment, the temperature distribution of the refrigeration oil inside the compressor occurs. Therefore, the calculation error of the solubility of refrigerant in the refrigeration oil inside the compressor is reduced. This makes it possible to accurately grasp the amount of refrigerant that has been dissolved and to accurately grasp the amount of refrigerant that is calculated by the refrigerant amount calculation means. Can be determined with high accuracy.

[0009] The air conditioner according to the fourth invention is the air conditioner according to the third invention. Therefore, the refrigerant quantity calculating means is an operating state quantity including at least the ambient temperature outside the compressor. Based on this, the amount of dissolved refrigerant is calculated.

In this air conditioner, the amount of dissolved refrigerant is calculated based on the amount of operating state that includes at least the ambient temperature outside the compressor. Therefore, some effects of the temperature distribution of the refrigeration oil inside the compressor are further taken into account. For example, the calculation error of the dissolved refrigerant amount can be further reduced as compared with the case where the dissolved refrigerant amount is calculated based only on the temperature of the refrigerant in contact with the refrigerating machine oil inside the compressor. It becomes like this. As a result, the refrigerant amount calculated by the refrigerant amount calculating means can be grasped more accurately. Therefore, the suitability of the refrigerant amount in the refrigerant circuit can be determined with higher accuracy. Brief Description of Drawings

FIG. 1 is a schematic configuration diagram of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a compressor.

FIG. 3 is a control block diagram of the air conditioner.

FIG. 4 is a flowchart of a test operation mode.

FIG. 5 is a flowchart of an automatic refrigerant charging operation.

FIG. 6 is a schematic diagram showing the state of refrigerant flowing in the refrigerant circuit in the refrigerant quantity determination operation (illustration of a four-way switching valve and the like is omitted).

FIG. 7 is a flowchart of a pipe volume determination operation.

FIG. 8 is a Mollier diagram showing the refrigeration cycle of the air conditioner in the pipe volume judgment operation for the liquid refrigerant communication pipe.

FIG. 9 is a Mollier diagram showing the refrigeration cycle of the air conditioner in the pipe volume judgment operation for the gas refrigerant communication pipe.

FIG. 10 is a flowchart of an initial refrigerant quantity determination operation.

FIG. 11 is a flowchart of a refrigerant leak detection operation mode.

FIG. 12 is a diagram showing the relationship between the intake and outdoor temperatures and the temperature of the refrigerating machine oil.

Explanation of symbols

[0011] 1 Air conditioner

10 Refrigerant circuit

21 Compressor

23 Outdoor heat exchanger (heat source side heat exchanger)

38 Outdoor expansion valve (expansion mechanism)

41, 51 Indoor expansion valve (expansion mechanism)

42, 52 Indoor heat exchange (use side heat exchange)

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of an air-conditioning apparatus according to the present invention will be described with reference to the drawings. (1) Configuration of air conditioner

FIG. 1 is a schematic configuration diagram of an air-conditioning apparatus 1 according to one 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 a single heat source unit, and indoor units 4 and 5 as a plurality of (two in this embodiment) usage units connected in parallel to the outdoor unit 2. The liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7 are provided as refrigerant communication pipes connecting the outdoor unit 2 and the indoor units 4 and 5. That is, in the vapor compression refrigerant circuit 10 of the air conditioner 1 of the present embodiment, the outdoor unit 2, the indoor units 4, 5, the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7 are connected. It is constituted by. In the present embodiment, an HFC refrigerant such as R407C, R410A, or R134a is sealed in the refrigerant circuit 10 as a refrigerant.

[0013] <Indoor unit>

The indoor units 4 and 5 are installed by being embedded or suspended in the ceiling of a room such as a building or by hanging on the 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. 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 indicates each part of the indoor unit 4 respectively. Instead of the 40's code, the 50's code is used, and the description of each part is omitted.

The indoor unit 4 mainly includes 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 has an indoor expansion valve 41 as an expansion mechanism and an indoor heat exchange 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. The In the present embodiment, the indoor heat exchange 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 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, and in this embodiment, the centrifugal fan or the multiblade fan driven by the motor 43a that also has DC fan motor power. Etc.

[0015] 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 heating operation or the evaporation temperature Te during cooling operation) is provided. ing. A gas side temperature sensor 45 for detecting the refrigerant temperature Teo is provided on the gas side of the indoor heat exchanger 42. An indoor temperature sensor 46 for detecting 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 the present embodiment, the liquid side temperature sensor 44, the gas side temperature sensor 45, and the room temperature sensor 46 are composed of thermistors. The indoor unit 4 also has an indoor side control unit 47 that controls the operation of each part constituting the indoor unit 4. The indoor control unit 47 includes a microcomputer, a memory, and the like provided for controlling the indoor unit 4, and a remote controller (not shown) for individually operating the indoor unit 4. Control signals etc. can be exchanged with the outdoor unit 2 and control signals etc. can be exchanged with the outdoor unit 2 via the transmission line 8a.

[0016] <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. Circuit 10 is configured.

Next, the configuration of the outdoor unit 2 will be described. The outdoor unit 2 mainly has a refrigerant circuit. The outdoor refrigerant circuit 10c constituting a part of the passage 10 is provided. This 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 exchange, an outdoor expansion valve 38 as an expansion mechanism, an accumulator 24, A supercooler 25 as a temperature adjusting mechanism, a liquid side closing valve 26 and a gas side closing valve 27 are provided.

The compressor 21 is a compressor whose operating capacity can be varied. In this embodiment, the compressor 21 is a capacity type compressor driven by a compressor motor 73 whose rotation speed Rm is controlled by an inverter. In the present embodiment, the number of the compressors 21 is only one, but is not limited to this, and two or more compressors may be connected in parallel according to the number of indoor units connected.

Next, the configuration of the compressor 21 will be described with reference to FIG. Here, FIG. 2 is a schematic longitudinal sectional view of the compressor 21. In this embodiment, the compressor 21 is a hermetic compressor in which a compression element 72 and a compressor motor 73 are incorporated in a compressor casing 71 that is a vertical cylindrical container.

The compressor casing 71 has a substantially cylindrical body plate 71a, an upper end plate 71b welded and fixed to the upper end of the body plate 71a, and a lower end plate 71c welded and fixed to the lower end of the body plate 71a. . In the compressor casing 71, a compression element 72 is mainly disposed at the upper part, and a compressor motor 73 is disposed below the compression element 72. The compression element 72 and the compressor motor 73 are connected by a shaft 74 arranged so as to extend in the up-down direction within the compressor casing 71. The compressor casing 71 is provided with a suction pipe 81 so as to penetrate the body plate 71a, and a discharge pipe 82 is provided so as to penetrate the upper end plate 71b. Of the spaces in the compressor casing 71, the space where the lower suction pipe 81 communicates with the compression element 72 is the low pressure space Q1 into which the low-pressure refrigerant flows into the compressor casing 71 through the suction pipe 81. It has become. Furthermore, in the present embodiment, an oil reservoir 71d is formed in the lower part of the low-pressure space Q1 to store the refrigerating machine oil necessary for lubricating the compressor 21 (particularly, the compression element 72). In this embodiment, ester oil or ether oil that is compatible with the HFC refrigerant is used as the refrigerating machine oil.

[0018] The compression element 72 is a mechanism for compressing the refrigerant therein, and this embodiment , A scroll-type compression element is employed, and a suction port 72a for sucking the refrigerant in the low pressure space Q1 is formed in the lower part, and a discharge port 72b for discharging the compressed high-pressure refrigerant is formed in the upper part. Has been. Of the space in the compressor casing 71, the space where the discharge pipe 82 on the upper side of the compression element 72 communicates is a high-pressure space Q2 into which high-pressure refrigerant flows through the discharge port 72b of the compression element 72. The compression element 72 is not limited to the scroll type compression element as in the present embodiment, and various types of compression elements such as a rotary type can be used.

The shaft 74 is formed with an oil passage 74a that opens to the oil reservoir 71d and communicates with the inside of the compression element 72. Refrigerating machine oil collected in the oil reservoir 71d is formed at the lower end of the oil passage 74a. Is provided with a pump element 74b for supplying the pressure to the compression element 72.

The compressor motor 73 is disposed in the low pressure space Q1 below the compression element 72, and an annular stator 73a fixed to the inner surface of the compressor casing 71 and a slight gap on the inner peripheral side of the stator 73a. And a rotor 73b accommodated in a freely rotatable manner. In the compressor 21 having such a configuration, when the compressor motor 73 is driven, a low-pressure refrigerant flows into the low-pressure space Q1 of the compressor casing 71 through the suction pipe 81 and is compressed by the compression element 72 to be high-pressure. Then, the refrigerant flows out from the high-pressure space Q2 of the compressor casing 71 through the discharge pipe 82. Here, the low-pressure refrigerant that has flowed into the low-pressure space Q1 is mainly composed of the refrigerating machine oil accumulated in the oil sump 71d as shown by the arrow drawn with a two-dot chain line indicating the flow of the suction refrigerant in FIG. After flowing in contact with the oil upper surface, the gap between the compressor motor 73 and the compressor casing 71 rises through the gap between the stator 73a and the rotor 73b and moves toward the suction port 72a formed at the lower part of the compression element 72. Will flow. The refrigerating machine oil accumulated in the oil reservoir 71d is in contact with the coolant, so that the refrigerating machine oil near the oil upper surface approaches the temperature of the refrigerant, and the compressor forming the oil reservoir 71d Since the refrigeration oil near the wall surface of the lower part of the casing 71 (mainly the lower end plate 71c) approaches the temperature of the wall surface, that is, the ambient temperature outside the compressor 21, the refrigeration oil accumulated in the oil reservoir 71d contains oil. A temperature distribution corresponding to the temperature difference between the temperature of the refrigerant in contact with the oil upper surface of the reservoir 71d and the ambient temperature outside the compressor 21 is generated. However, the refrigerant in contact with the oil upper surface of the oil reservoir 71d is steamed during the cooling operation. It is a low-pressure refrigerant that returns from the indoor heat exchangers 42 and 52 that function as generators, and a low-pressure refrigerant that returns from the outdoor heat exchanger 23 that functions as an evaporator during heating operation. Since the temperature is close to the temperature of the air, the temperature difference from the ambient temperature outside the compressor 21 is within 50 ° C at the maximum. That is, in the air conditioner 1 of the present embodiment, the maximum value of the temperature difference between the refrigerating machine oil accumulated in the oil reservoir 71d inside the compressor 21 and the refrigerant in contact with the refrigerating machine oil is 50 ° C. or less. The temperature distribution of the refrigerating machine oil collected in the oil reservoir 71d inside the compressor 21 is generated.

[0020] 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 serves as a refrigerant condenser compressed by the compressor 21, and the indoor In order for the heat exchangers 42 and 52 to function as an evaporator for the refrigerant condensed in the outdoor heat exchanger 23, the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 23 are connected and the suction side of the compressor 21 ( Specifically, the accumulator 24) and the gas refrigerant communication pipe 7 side are connected (see the solid line of the four-way selector valve 22 in Fig. 1), and the indoor heat exchangers 42 and 52 are connected to the compressor 21 during heating operation. In order to allow 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 the suction side of the compressor 21 and the gas side of the outdoor heat exchange Can be connected (see the dashed line of the four-way selector valve 22 in FIG. 1).

[0021] In the present embodiment, the outdoor heat exchange 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. This is heat exchange 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 coolant communication pipe 6.

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 is a blower fan for sucking outdoor air into the unit and exchanging heat with the refrigerant in the outdoor heat exchanger 23 and then discharging it to the outdoor. All outdoor fans 28 are provided. 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 this embodiment, the outdoor fan 28 is a propeller fan or the like driven by a motor 28a having a DC fan motor power. is there.

[0022] The accumulator 24 is connected between the four-way switching valve 22 and the compressor 21, and removes excess refrigerant generated in the refrigerant circuit 10 in accordance with fluctuations in the operation load of the indoor units 4 and 5. It is a container that can be stored.

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 supercooler 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, the part excluding the bypass refrigerant circuit 61 from the refrigerant circuit 10 will be referred to as a main refrigerant circuit for convenience.

[0023] The bypass refrigerant circuit 61 is provided in the main refrigerant circuit so that a part of the refrigerant sent from the outdoor heat exchanger 23 to the indoor expansion valves 41, 51 is branched from the main refrigerant circuit and returned to the suction side of the compressor 21. It is connected. Specifically, the bypass refrigerant circuit 61 connects a part of the refrigerant sent from the outdoor expansion valve 38 to the indoor expansion valves 41 and 51 so that the positional force between the outdoor heat exchanger and the subcooler 25 also branches. And the junction circuit 61b connected to the suction side of the compressor 21 so as to return to the suction side of the compressor 21 from the outlet of the bypass refrigerant circuit side of the subcooler 25. . The branch circuit 61a 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 also has an electric expansion valve force. Thus, 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 no-pass 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.

[0024] The liquid side shut-off valve 26 and the gas side shut-off 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 stop valve 27 is in contact with the four-way selector valve 22. It has been continued.

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 the compressor 21. A suction temperature sensor 31 for detecting the suction temperature Ts 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 includes 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 that detects the temperature of the refrigerant (that is, the liquid pipe temperature Tip) is provided at the outlet of the subcooler 25 on the main refrigerant circuit side. The junction circuit 6 lb of the no-pass 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 this embodiment, the outdoor temperature sensor 36 detects the temperature of the outdoor air flowing into the unit, so that the outside of various devices such as the compressor 21 provided in the outdoor unit 2 is externally detected. It can be said that this shows the ambient temperature. 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 part constituting the outdoor unit 2. The outdoor control unit 37 includes a microcomputer provided for controlling the outdoor unit 2, an inverter circuit that controls the memory and the compressor motor 73, and the like. Control signals can be exchanged between the control units 47 and 57 via the transmission line 8a. That is, the control unit 8 that controls the overall operation of the air conditioner 1 is configured by the indoor control units 47 and 57, the outdoor control unit 37, and the transmission line 8a that connects the control units 37, 47, and 57. Yes. [0025] 咅 U 咅 ί 8ί, Fig. 3 [As shown, this is connected to receive the detection signals of various sensors 29-36, 44-46, 54-56, 63, Based on these detection signals, etc., various devices and valves 21, 22, 24, 28a, 38, 41, 43a, 51, 53a, 62 are connected so that they can be controlled. In addition, the control unit 8 is connected to a warning display unit 9 that is an LED or the like for notifying that a refrigerant leak has been detected in the refrigerant leak detection operation described later. Here, FIG. 3 is a control block diagram of the air conditioner 1.

Refrigerant communication pipes 6 and 7 are refrigerant pipes that are installed on site when the air conditioner 1 is installed in a building or other location, such as a combination of the installation location or outdoor unit and indoor unit. Depending on the installation conditions, those having various lengths and pipe diameters are used. For this reason, for example, when a new air conditioner is installed, it is necessary to accurately grasp information such as the length of the refrigerant communication pipes 6 and 7 in order to calculate the additional refrigerant charging amount. Although there is information management, the calculation of the refrigerant amount itself is complicated. In addition, when the existing unit is used to update the indoor unit or the outdoor unit, the blueprints such as the length and diameter of the refrigerant communication pipes 6 and 7 may be lost.

[0026] As described above, the refrigerant circuit 10 of the air conditioner 1 is configured by connecting the indoor refrigerant circuits 10a, 10b, the outdoor refrigerant circuit 10c, and the refrigerant communication pipes 6, 7. . In other words, the refrigerant circuit 10 can be paraphrased as being composed of a bypass refrigerant circuit 61 and a main refrigerant circuit excluding the bypass refrigerant circuit 61. The air conditioner 1 according to 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 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 of the air conditioner

Next, the operation of the air conditioner 1 of the present embodiment will be described.

[0027] The operation mode of the air conditioner 1 of the present embodiment is a normal operation mode in which the components of the outdoor unit 2 and the indoor units 4, 5 are controlled in accordance with the operation load of each indoor unit 4, 5. After installing the components of the air conditioner 1 (specifically, only after installing the first device) (For example, after remodeling such as adding or removing components such as indoor units, or after repairing the equipment failure, etc.) After starting normal operation, there is a refrigerant leakage detection operation mode in which the presence or absence of refrigerant leakage from the refrigerant circuit 10 is determined. The normal operation mode mainly includes a cooling operation for cooling the room and a heating operation for heating the room.

. In the test operation mode, the automatic refrigerant charging operation for charging the refrigerant into the refrigerant circuit 10, the pipe volume determination operation for detecting the volume of the refrigerant communication pipes 6 and 7, and after the installation of the components or the refrigerant And an initial refrigerant quantity detection operation for detecting the initial refrigerant quantity after the refrigerant is filled in the circuit.

Hereinafter, the operation in each operation mode of the air conditioner 1 will be described.

(Cooling operation)

First, the cooling operation in the normal operation mode will be described with reference to FIGS. 1 and 3.At the time of the cooling operation, the four-way switching valve 22 is in the state indicated by the solid line in FIG. 1, that is, the discharge side of the compressor 21 is the outdoor heat. It is connected to the gas side of the exchanger 23, and the suction side of the compressor 21 is connected to the gas side of the indoor heat exchangers 42 and 52 via the gas side closing valve 27 and the gas refrigerant communication pipe 7. Yes. 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. The indoor expansion valves 41 and 51 are opened so 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 degree is adjusted! / In the present embodiment, the degree of superheat SHr of the refrigerant at the outlets of the indoor heat exchangers 42, 52 is the refrigerant temperature value detected by the gas side temperature sensors 45, 55, and the refrigerant temperature sensors 44, 54 also detect the refrigerant temperature value force. 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 this embodiment, the temperature of the refrigerant flowing in each indoor heat exchanger 42, 52 is detected. A temperature sensor is provided, and the refrigerant temperature value corresponding to the evaporation temperature Te detected by this temperature sensor is subtracted from the refrigerant temperature value detected by the gas side temperature sensors 45 and 55, thereby making it possible to The degree of superheat SHr of the refrigerant at the outlets of the heat exchangers 42 and 52 may be detected. Further, the bypass expansion valve 62 is adjusted in opening degree so that the superheat degree SHb of the refrigerant at the outlet on the bypass refrigerant circuit side of the supercooler 25 becomes the superheat degree target value SHbs. In this embodiment, the superheat degree SHb of the refrigerant at the outlet on the bypass refrigerant circuit side of the subcooler 25 is the saturation temperature value corresponding to the evaporation pressure Te, which is the suction pressure Ps of the compressor 21 detected by the suction pressure sensor 29. Is detected by subtracting the saturation temperature value of the refrigerant from the refrigerant temperature value detected by the bypass temperature sensor 63. Although not adopted in this embodiment, a temperature sensor is provided at the bypass refrigerant circuit side inlet of the subcooler 25, and the refrigerant temperature value detected by this temperature sensor is detected by the bypass temperature sensor 63. The refrigerant superheat degree SHb at the outlet of the subcooler 25 on the bypass refrigerant circuit side may be detected by subtracting the refrigerant temperature value.

[0029] 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. Become. After that, 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. Then, this high-pressure liquid refrigerant passes through the outdoor expansion valve 38 and 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 exchange 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 binos expansion valve 62 is evaporated by being reduced to near the suction pressure Ps of the compressor 21. Then, the refrigerant flowing in the direction of the outlet force of the bypass expansion valve 62 of the bypass refrigerant circuit 61 toward the suction side of the compressor 21 passes through the subcooler 25 and from the outdoor heat exchanger 23 on the main refrigerant circuit side. Exchanges heat with high-pressure liquid refrigerant sent to indoor units 4 and 5.

[0030] Then, the high-pressure liquid refrigerant in a supercooled state is connected to the liquid-side stop valve 26 and the liquid refrigerant communication line. It is sent to indoor units 4 and 5 via pipe 6. The high-pressure liquid refrigerant sent to the indoor units 4 and 5 is decompressed to near the suction pressure Ps of the compressor 21 by the indoor expansion valves 41 and 51 to become a low-pressure gas-liquid two-phase refrigerant and exchanges heat in the room. The heat is exchanged with the indoor air in the indoor heat exchangers 42 and 52 to evaporate and become 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.

[0031] 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 exchanger 42 via the gas-side closing valve 27 and the gas refrigerant communication pipe 7. 52, and the suction side of the compressor 21 is connected to the gas side of the outdoor heat exchanger 23. The degree of opening of the outdoor expansion valve 38 is adjusted to reduce the pressure of the refrigerant flowing into the outdoor heat exchanger 23 to a pressure at which the refrigerant can be evaporated in the outdoor heat exchanger (that is, the evaporation pressure Pe). Further, the liquid side closing valve 26 and the gas side closing valve 27 are opened. The indoor expansion valves 41 and 51 are adjusted in opening degree 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 degree of refrigerant supercooling SCr at the outlets of the indoor heat exchangers 42 and 52 is the saturation temperature value corresponding to the condensation temperature Tc, which is the discharge pressure Pd of the compressor 21 detected by the discharge pressure sensor 30. 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 indoor heat exchanger 42, 52 is provided, and the refrigerant corresponding to the condensation temperature Tc detected by this temperature sensor. The subcooling degree SCr of the refrigerant at the outlets of the indoor heat exchangers 42, 52 may be detected by subtracting the temperature value from the refrigerant temperature value detected by the liquid side temperature sensors 44, 54. Further, the bypass expansion valve 62 is closed.

[0032] 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. Thus, the indoor units 4 and 5 are sent through the four-way switching 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. When passing through the expansion valves 41 and 51, the pressure is reduced according to the opening degree of the indoor expansion valves 41 and 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 passes through the liquid side closing valve 26, the supercooler 25, and the outdoor expansion valve 38. The pressure is further reduced and then 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. Flows into the accumulator 24 via. Then, the low-pressure gas refrigerant that has flowed into the accumulator 24 is again sucked into the compressor 21.

[0033] The 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, 57 functioning as normal operation control means for performing normal operation including cooling operation and heating operation. And the transmission line 8a) connecting the outdoor control unit 37 and the control units 37, 47, and 57.

Next, the trial operation mode will be described with reference to FIGS. Here, Fig. 4 is a flowchart of the test operation mode. In the present embodiment, in the test operation mode, first, the automatic refrigerant 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 pre-filled with the refrigerant and the indoor units 4 and 5 are installed at a place 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 refrigerant circuit 10 is configured, the refrigerant circuit 10 is additionally filled with a refrigerant that is insufficient in accordance with the volume of the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7.

[0034] (Step S1: Refrigerant automatic charging operation)

First, open the liquid side shutoff valve 26 and the gas side shutoff valve 27 of the outdoor unit 2 to open the outdoor unit 2. The refrigerant circuit 10 is filled with the refrigerant prefilled in 2.

Next, an operator who performs a test run connects a refrigerant cylinder for additional charging to a service port (not shown) of the refrigerant circuit 10 and directly or remotely controls the control unit 8. When a command to start a test run from a remote location is issued, the control unit 8 performs steps S11 to S13 shown in FIG. Here, FIG. 5 is a flowchart of the automatic refrigerant charging operation.

(Step S11: Refrigerant amount judgment 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. 1 and the indoor expansion valves 41 of the indoor units 4 and 5 51 and outdoor expansion valve 38 are opened, compressor 21, outdoor fan 28 and indoor fans 4 3, 53 are activated, and all indoor units 4, 5 are forcibly cooled (hereinafter referred to as the total number of indoor units). Driving).

Then, as shown in FIG. 6, in the refrigerant circuit 10, the high-pressure gas refrigerant compressed and discharged in the compressor 21 flows through the flow path from the compressor 21 to the outdoor heat exchange functioning as a condenser ( (Refer to the hatched portion in Fig. 6 from the compressor 21 to the outdoor heat exchanger 23), and the outdoor heat exchanger 23 functioning as a condenser is changed from a gas state to a liquid state by heat exchange with the outdoor air. (Refer to the portion corresponding to the outdoor heat exchanger 23 in the hatched and black hatched portions in FIG. 6), and from the outdoor heat exchanger 23 to the indoor expansion valves 41, 51 High-pressure liquid is present in the flow path including the outdoor expansion valve 38, the part of the subcooler 25 on the main refrigerant circuit side and the liquid refrigerant communication pipe 6 and the flow path from the outdoor heat exchanger 23 to the bypass expansion valve 62. The refrigerant flows (out of the black hatched parts in Fig. 6). (Refer to the section from the external heat exchanger 23 to the indoor expansion valves 41 and 51 and the bypass expansion valve 62), the indoor heat exchanger 42 and 52 functioning as an evaporator, and the bypass refrigerant circuit side of the subcooler 25 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 into the part (in the part of the grid-like hatching and hatched hatching in Fig. 6 42, 52 and the subcooler 25)), the flow path including the indoor refrigerant heat exchanger 42, 52 to the compressor 21 and the flow path including the accumulator 2 4 and the bypass refrigerant of the subcooler 25 The partial force on the circuit side is also the flow path to the compressor 21 The low-pressure gas refrigerant flows through (the hatched part in Fig. 6 is the part from the indoor heat exchanger ^^ 42, 52 to the compressor 21 and the part on the bypass refrigerant circuit side of the subcooler 25) (See also force to compressor 21). FIG. 6 is a schematic diagram showing 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).

[0036] 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). The operation capacity of the compressor 21 is controlled so as to be constant (hereinafter referred to as evaporation pressure control), and the outdoor fan 28 is used for outdoor heat exchange so that the refrigerant condensation pressure Pc in the outdoor heat exchanger 23 is constant. The subcooler is controlled so that the air volume Wo of the outdoor air supplied to the cooler 23 is controlled (hereinafter referred to as condensing pressure control) and the temperature of the refrigerant sent from the supercooler 25 to the indoor expansion valves 41 and 51 is constant. The indoor fan 43, 53 controls the indoor heat exchanger 42 so that the refrigerant evaporating pressure Pe is controlled stably by the above evaporating pressure control. The air volume Wr of the indoor air supplied to No. 52 is kept constant.

[0037] Here, the evaporation pressure control is performed in the indoor heat exchangers 42 and 52 functioning as an evaporator in a gas-liquid two-phase state force due to heat exchange with the room air, while the phase is changed to a gas state and a low pressure. Inside the indoor heat exchanger ^^ 42, 52 through which the refrigerant flows (see the part corresponding to the indoor heat exchangers 42, 52 in the grid-shaped, hatching and hatched hatching parts in Fig. 6; This is because the amount of refrigerant in (part C) greatly affects the evaporation pressure Pe of the refrigerant. And here, by controlling the operating capacity of the compressor 21 by the compressor motor 73 whose rotation speed Rm is controlled by the inverter, the evaporation pressure Pe of the refrigerant in the indoor heat exchangers 42 and 52 is kept constant, and the evaporation The state of the refrigerant flowing in the vessel part C is stabilized, and a state in which the amount of refrigerant in the evaporator C is changed 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, 54 of the indoor heat exchangers 42, 52 is the saturation pressure. In order to make this pressure value constant at the low pressure target value Pes, This is realized by controlling the operating capacity of 1 (that is, by controlling the rotational speed Rm of the compressor motor 73) to increase or decrease the refrigerant circulation amount Wc flowing in the refrigerant circuit 10. Although not adopted in the present embodiment, the suction of the compressor 21 detected by the suction pressure sensor 29, which is an operation state quantity equivalent to the refrigerant pressure at the refrigerant evaporating pressure Pe in the indoor heat exchangers 42 and 52, The compressor 21 is set so that the 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. May be controlled, and 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. Thus, the operating capacity of the compressor 21 may be controlled. By performing such evaporation pressure control, the refrigerant refrigerant pipe including the gas refrigerant communication pipe 7 and the accumulator 24 from the indoor heat exchangers 42 and 52 to the compressor 21 (the hatched portion in FIG. Among these, the state of the refrigerant flowing through the indoor heat exchangers 42 and 52 to the compressor 21 (hereinafter referred to as gas refrigerant circulation section D) is also stable, and mainly the refrigerant flow in the gas refrigerant circulation section D. A state is created 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 an operation state amount equivalent to the pressure.

Condensation pressure control is performed in the outdoor heat exchanger ^^ 23 in which high-pressure refrigerant flows while the gas state force changes to a liquid state due to heat exchange with the outdoor air (hatched hatched and blacked out in Fig. 6). Among the hatched portions, see the portion corresponding to the outdoor heat exchanger 23 (hereinafter referred to as the condenser portion A), which is also the force that greatly affects the refrigerant condensing pressure Pc. Since the refrigerant condensing pressure Pc in the condenser part A changes greatly due to the influence of the outdoor temperature Ta, the air volume Wo of the indoor air supplied from the outdoor fan 28 to the outdoor heat exchanger 23 is controlled by the motor 28a. As a result, the condensation pressure Pc of the refrigerant in the outdoor heat exchanger 23 is made constant, and the state of the refrigerant flowing in the condenser section A is stabilized, and mainly the liquid side of the outdoor heat exchanger 23 (hereinafter referred to as the refrigerant). In the description of the quantity determination operation, the refrigerant amount in the condenser A is changed by the degree of supercooling SCo at 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 operation state equivalent to the refrigerant condensation pressure Pc in the outdoor heat exchanger 23 is used. The discharge pressure Pd of the compressor 21 detected by the discharge pressure sensor 30 or the temperature of the refrigerant flowing in the outdoor heat exchanger 23 detected by the heat exchange temperature sensor 33 (that is, the condensation temperature Tc ) Is used.

[0039] Then, by performing such condensing pressure control, the outdoor expansion valve 38 from the outdoor heat exchange to the indoor expansion valves 41, 51, the part on the main refrigerant circuit side of the supercooler 25, and the liquid refrigerant communication pipe 6 and the flow from the outdoor heat exchanger 23 to the flow path from the bypass refrigerant circuit 61 to the bypass expansion valve 62, a high-pressure liquid refrigerant flows from the outdoor heat exchanger 23 to the indoor expansion valves 41, 51 and The pressure of the refrigerant in the portion up to the binos expansion valve 62 (refer to the black hatched portion in FIG. 6, hereinafter referred to as the liquid refrigerant circulation section B) is stable, and the liquid refrigerant circulation section B is sealed with the liquid refrigerant. It will be in a stable state.

The liquid pipe temperature control is performed in the refrigerant pipe including the liquid refrigerant communication pipe 6 from the subcooler 25 to the indoor expansion valves 41 and 51 (the subcooler in the liquid refrigerant circulation section B shown in FIG. 6). This is to prevent the refrigerant density from changing from 25 to the indoor expansion valves 41 and 51). The capacity control of the subcooler 25 is controlled so that the refrigerant temperature Tip 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 Tips. In this way, the flow rate of the refrigerant flowing through the bypass refrigerant circuit 61 is increased or 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 way, 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.

[0040] Then, by performing such liquid pipe temperature constant control, the refrigerant heat is filled in the refrigerant circuit 10, and as the amount of refrigerant in the refrigerant circuit 10 gradually increases, the outdoor heat exchange 23 The refrigerant temperature Tco at the outlet of the outdoor heat exchanger 23 is changed even when the refrigerant temperature Tco at the outlet of the outdoor heat exchanger 23 changes (that is, the degree of refrigerant supercooling SCo at the outlet of the outdoor heat exchanger 23). The influence of this change and the outlet force of the outdoor heat exchange are also contained only in the refrigerant pipe that reaches the subcooler 25, and in the liquid refrigerant circulation section B, from the subcooler 25 to the indoor expansion valves 41 and 51 including the liquid refrigerant communication pipe 6 The refrigerant piping is not 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 outlet of the indoor heat exchanger 52 is controlled by controlling the opening degree of the indoor expansion valves 41 and 51, so that the gas side of the indoor heat exchangers 42 and 52 (hereinafter referred to as refrigerant amount determination operation). In the explanation, the superheat degree SHr of the refrigerant in the indoor heat exchangers 42 and 52 is made constant at the superheat 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.

[0041] By performing such superheat control, a state in which the gas refrigerant surely flows in the gas refrigerant communication section D is created.

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 becomes constant. When the refrigerant begins to be charged, it is possible to create a state in which the change in the refrigerant amount in the refrigerant circuit 10 mainly appears as a change in the refrigerant amount in the outdoor heat exchanger 23 (hereinafter, this operation is performed). Is the refrigerant quantity determination operation).

The control as described above is 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, which functions as a refrigerant amount determination operation control unit that performs the refrigerant amount determination operation. The transmission line 8a) connecting 47 and 57 is performed as the process of step S11.

[0042] Unlike the present embodiment, when the outdoor unit 2 is not prefilled with the refrigerant, the component device abnormally stops when the above-described refrigerant amount determination operation is performed prior to the processing of step S11. It is necessary to charge the refrigerant until the amount of refrigerant is low enough

(Step S12: Calculation of refrigerant quantity)

Next, additional refrigerant charging is performed in the refrigerant circuit 10 while performing the above-described refrigerant amount determination operation. At this time, the additional charging of the refrigerant in step S12 is performed by the control unit 8 functioning as the refrigerant amount calculating means. The refrigerant amount in the refrigerant circuit 10 is calculated from the refrigerant flowing through the refrigerant circuit 10 at the time 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 divides the refrigerant circuit 10 into a plurality of parts, and calculates the refrigerant quantity for each of the divided parts. Thus, the amount of refrigerant in the refrigerant circuit 10 is calculated. More specifically, for each of the divided parts, 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. By using it, the amount of refrigerant in each part can be calculated. And in this embodiment, a refrigerant circuit

10 shows a state in which the four-way switching valve 22 is shown by a 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 closed to the gas side. The outdoor heat exchanger including the four-way switching valve 22 (not shown in FIG. 6) from the compressor 21 in a state connected to the outlets of the indoor heat exchangers 42 and 52 through the valve 27 and the gas refrigerant communication pipe 7 2 The parts up to 3 (hereinafter referred to as “high pressure gas pipe part E”), the part of the outdoor heat exchanger 23 (namely, the condenser part A) and the liquid refrigerant circulation part B are supercooled from the outdoor heat exchanger 23. The main refrigerant circuit of the subcooler 25 in the liquid refrigerant circulation part B and the inlet-side half of the main refrigerant circuit side part of the subcooler 25 and the part of the subcooler 25 (hereinafter referred to as the high temperature side liquid pipe part B1). And the part from the subcooler 25 to the liquid side shutoff valve 26 (not shown in FIG. 6) (hereinafter referred to as the low temperature side liquid pipe part B2) The liquid refrigerant communication pipe 6 in the liquid refrigerant circulation section B (hereinafter referred to as the liquid refrigerant communication pipe section B3) and the liquid refrigerant communication pipe 6 in the liquid refrigerant circulation section B through the indoor expansion valves 41, 51 and the indoor Of the gas refrigerant circulation part D including the heat exchangers 42 and 52 (that is, the evaporator part C), the part up to the gas refrigerant communication pipe 7 (hereinafter referred to as the indoor unit part F), and the gas refrigerant circulation part A part of the gas refrigerant communication pipe 7 in D (hereinafter referred to as gas refrigerant communication pipe part G) and a gas side closing valve 27 (not shown in FIG. 6) of the gas refrigerant circulation part D to a four-way switching valve 22 And the portion up to the compressor 21 including the accumulator 24 (hereinafter referred to as the low-pressure gas pipe section H) and the high-temperature side liquid pipe section B1 from the liquid refrigerant circulation section B to the bypass expansion valve 62 and the subcooler 25 bypass refrigerant. The part up to the low pressure gas pipe part H including the part on the circuit side (hereinafter referred to as bypass circuit part I) and compression The machine 21 is divided into parts (hereinafter referred to as compressor part J), and a relational expression is set for each part. Next, the relational expressions set for each part will be described.

In the present embodiment, the relational expression between the refrigerant amount Mogl in the high-pressure gas pipe E and the operating state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,

Mogl = Vogl X pd This is expressed as a functional expression obtained by multiplying the volume Vogl of the high-pressure gas pipe E of the outdoor unit 2 by the refrigerant density / 0 d in the high-pressure gas pipe E. Note that the volume Vogl of the high-pressure gas pipe E is a known value of the front force at which the outdoor unit 2 is installed at the installation location, and is stored in advance in the memory of the control unit 8. The density 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 quantity 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 = kcl XTa + kc2 XTc + kc3 X SHm + kc4 XWc

+ kc5 X pc + kco X p CO + C I

The outdoor temperature Ta, the condensation temperature Tc, the compressor discharge superheat SHm, the refrigerant circulation rate Wc, the saturated liquid density pc of the refrigerant in the outdoor heat exchanger 23, and the refrigerant density P at the outlet of the outdoor heat exchanger 23 It is expressed as a function expression of co. The parameters kcl 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 S Hm is the refrigerant superheat degree on the discharge side of the compressor. The discharge pressure Pd is converted to the refrigerant saturation temperature value, and the discharge temperature Td force is subtracted from the refrigerant saturation temperature value. Can be obtained. The refrigerant circulation amount Wc is expressed as a function of the evaporation temperature Te and the condensation temperature Tc (that is, Wc = fl (Te, Tc)). The saturated liquid density pc of the refrigerant can be obtained by converting the condensation temperature Tc. The refrigerant density p co 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 Moll in the high-temperature liquid pipe section B1 and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,

Moll = Voll X p co

t, u, a functional equation that multiplies the volume Voll of the high-temperature liquid pipe section B1 of the outdoor unit 2 by the refrigerant density p co in the high-temperature liquid pipe section B1 (that is, the refrigerant density at the outlet of the outdoor heat exchanger 23 described above). Represented as: The volume Voll of the high-pressure liquid pipe section B1 is a known value of the front force at which the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control section 8 in advance. The relational expression between the refrigerant quantity Mol2 in the low temperature liquid pipe part B2 and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,

Mol2 = Vol2 X ip

This is expressed as a functional expression obtained by multiplying the volume Vol2 of the cryogenic liquid pipe section B2 of the outdoor unit 2 by the refrigerant density p lp in the cryogenic liquid pipe section B2. Note that the volume Vol2 of the cryogenic liquid pipe section B2 is a known value of the front force at which the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control section 8 in advance. The refrigerant density p lp in the cryogenic liquid pipe section B2 is the refrigerant density at the outlet of the subcooler 25, and is obtained by converting the condensation pressure Pc and the refrigerant temperature Tip at the outlet of the subcooler 25. It is done.

[0045] The relational expression between the refrigerant amount Mlp in the liquid refrigerant communication pipe section B3 and the operating state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,

Mlp = Vlp X ip

This is expressed as a function equation obtained by multiplying the volume Vlp of the liquid refrigerant communication pipe 6 by the refrigerant density lp (that is, the refrigerant density at the outlet of the subcooler 25) in the liquid refrigerant communication pipe section B3. Note that the volume Vlp of the liquid refrigerant communication pipe 6 is a refrigerant pipe that is installed locally when the liquid refrigerant communication pipe 6 is installed at the installation location of the air conditioner 1 at a place such as a building. Input the value calculated locally from the information, etc., or input the information such as the pipe diameter at the site, and the control section 8 also calculates the information power of these input liquid refrigerant communication pipes 6 Or, as will be described later, calculation is performed using the operation result of the pipe volume determination operation.

[0046] The relational expression between the refrigerant quantity Mr in the indoor unit F and the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device is, for example,

Mr = krl XTlp + kr2 X AT + kr3 X SHr + kr4 XWr + kr5

The refrigerant temperature Tlp at the outlet of the supercooler 25, the temperature difference ΔΤ 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. Note that the parameters krl to kr5 in the above relational expression are obtained by regression analysis of the results of the test and detailed simulation, and are stored in the memory of the control unit 8 in advance. Here, the relational expression of the refrigerant amount Mr is set for each of the two indoor units 4 and 5. The total refrigerant quantity of the indoor unit F is calculated by adding the refrigerant quantity Mr of the indoor unit 4 and the refrigerant quantity Mr of the indoor unit 5. If the indoor unit 4 and the indoor unit 5 have different models and capacities, the relational forces S with different values of the parameters krl to kr5 will be used.

[0047] The relational expression between the refrigerant amount Mgp in the gas refrigerant communication pipe section G and the operating state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,

Mgp = Vgp X gp

This is expressed as a function expression obtained by multiplying the volume Vgp of the gas refrigerant communication pipe 7 by the refrigerant density p gp in the gas refrigerant communication pipe section H. Note that the volume Vgp of the gas refrigerant communication pipe 7 is the refrigerant installed at the site when the gas refrigerant communication pipe 7 installs the air conditioner 1 at the installation location of the building, etc., like the liquid coolant communication pipe 6. Because it is a pipe, input the value calculated locally from the information such as the pipe diameter or the length, or enter the information such as the pipe diameter at the local, and the information of the gas refrigerant communication pipe 7 that has been input It is calculated by the force control unit 8 or is calculated using the operation result of the pipe volume determination operation as described later. In addition, the refrigerant density p gp in the gas refrigerant pipe connecting portion G is equal to the refrigerant density P s on the suction side of the compressor 21 and the outlets of the indoor heat exchangers 42 and 52 (that is, the inlet of the gas refrigerant connecting pipe 7). This is the average value with the density p eo of the refrigerant. The refrigerant density ps is obtained by converting the suction pressure Ps and the suction temperature Ts, and the refrigerant density p eo is obtained by converting the evaporation pressure Pe and the indoor heat exchangers 42 and 52, which are conversion values of the evaporation temperature Te. It is obtained by converting the outlet temperature Teo.

[0048] The relational expression between the refrigerant amount Mog2 in the low-pressure gas pipe portion H and the operating state quantity of the refrigerant or the component device flowing through the refrigerant circuit 10 is, for example,

Mog2 = Vog2 X p s

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 p s in the low-pressure gas pipe H. Note that the volume Vog2 of the low-pressure gas pipe H is a known value of the pre-force that is shipped to the installation location, and is stored in the memory of the controller 8 in advance.

Refrigerant amount Mob in nopass circuit section I and refrigerant or component equipment flowing in refrigerant circuit 10 The relational expression with the driving state quantity is, for example,

Mob = kobl X co + kob2 X ps + kob3 X Pe + kob4

The refrigerant density p co at the outlet of the outdoor heat exchanger 23, the refrigerant density p s at the outlet of the subcooler 25 on the bypass circuit side, and the evaporation pressure Pe are expressed as functional expressions. Note that the parameters kobl 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 part I may be smaller than the other parts, and may be calculated by a simpler relational expression. For example,

Mob = Vob X e X kob5

This is expressed as a functional expression obtained by multiplying the volume Vob of the bypass circuit portion I by the saturated liquid density p e and the correction coefficient kob in the bypass circuit side portion of the subcooler 25. Incidentally, the volume Vob of the bypass circuit section I is also a known value of the front force at which the outdoor unit 2 is installed at the installation location, and is stored in the memory of the control section 8 in advance. Further, the saturated liquid density pe in the portion on the bypass circuit side of the subcooler 25 can be obtained by converting the suction pressure Ps or the evaporation temperature Te.

The relational expression between the refrigerant amount Mcomp in the compressor part J and the operating state quantity of the refrigerant or the component equipment flowing through the refrigerant circuit 10 is, for example,

Mcomp = Mqo + Mq 1 + Mq2

That is, the amount of dissolved refrigerant Mqo that is accumulated in the oil reservoir 71d in the low pressure space Ql in the compressor casing 71 of the compressor 21 and dissolved in the refrigerating machine oil, and the compressor casing 71 of the compressor 21 This is expressed as a function equation obtained by adding the refrigerant amount Mql in the portion other than the oil reservoir 71d in the low pressure space Q1 and the refrigerant amount Mq2 in the high pressure space Q2 in the compressor casing 71 of the compressor 21.

Here, if the amount of refrigeration oil is Moil and the solubility of the refrigerant in the refrigeration oil is φ, the dissolved refrigerant amount Mqo is

Mqo = / (ΐ-) X Moil

Represented as: The refrigerant solubility φ in the refrigerating machine oil is expressed as a function of the pressure and temperature of the refrigerating machine oil accumulated in the oil reservoir 71d. Thus, the refrigerant pressure (that is, the suction pressure Ps) in the low pressure space Q1 can be used, and the refrigerating machine oil collected in the oil sump 71d in the compressor 21 by the air conditioner 1 in the present embodiment can be used. The maximum temperature difference with the refrigerant in contact with the refrigerating machine oil is configured to be 50 ° C or less, resulting in a temperature distribution of the refrigerating machine oil accumulated in the oil reservoir 71d inside the compressor 21. Therefore, the temperature of the refrigerant in the low-pressure space Q1 (that is, the suction temperature Ts) can be used as the temperature of the refrigerating machine oil. That is, the refrigerant solubility Φ in the refrigeration oil is a function of the refrigerant pressure and temperature (i.e., suction pressure Ps and suction temperature Ts) in the low-pressure space Q1 where the oil reservoir 71d is formed (i.e., φ = f2 (Ps , Ts))). As described above, the dissolved refrigerant amount Mqo can also calculate a known amount of refrigerating machine oil Moil, suction pressure Ps, and suction temperature Ts force.

[0050] The refrigerant amount Mql is

Mql = (Vcomp-Voil-Vq2) X p s

This is calculated by subtracting the total volume Vcomp of compressor 21 and the volume Voil of the refrigeration oil and the volume Vq2 of the high-pressure space Q2, and multiplying this by the refrigerant density ps as the refrigerant density in the low-pressure space Q1. The

Here, the volume Voil of the refrigeration oil is calculated by dividing the amount Moil of the refrigeration oil by the density p oil of the refrigeration oil. The density p oil of the refrigerating machine oil is expressed as a function of the temperature of the refrigerating machine oil. In this case as well, as in the case of calculating the solubility φ described above, the refrigerant temperature (that is, the suction) in the low-pressure space Q1. Temperature Ts) can be used. That is, the density of the refrigerating machine oil can be expressed as a function (that is, oilzfS CTs) of the temperature of the refrigerant (that is, the suction temperature Ts) in the low pressure space Q1 in which the oil reservoir 71d is formed. As described above, the refrigerant amount Mql in the low-pressure space Q1 in the compressor casing 71 of the compressor 21 other than the oil reservoir 71d is the known volume Vcomp, the known volume Vq2, and the known amount of refrigeration oil Moil. And the suction temperature Ts.

[0051] The refrigerant amount Mq2 is

Mq2 = Vq2 X p d

This is calculated by multiplying the volume Vq2 of the high-pressure space Q2 by the refrigerant density pd as the refrigerant density in the high-pressure space Q2. In the present embodiment, there is only one outdoor unit 2 force. When a plurality of outdoor units are connected, a plurality of refrigerant quantities Mogl, Mc, Moll, Mol2, Mog2, Mob, and Mcomp related to the outdoor unit are present. The relational expression of the refrigerant quantity of each part is set corresponding to each of the outdoor units, and the total refrigerant quantity of the outdoor unit is calculated by adding the refrigerant quantity of each part of the plurality of outdoor units. ing. When multiple outdoor units with different models and capacities are connected, the relational expression for the refrigerant amount of each part with different parameter values is used.

[0052] As described above, in the present embodiment, using the relational expression for each part of the refrigerant circuit 10, the refrigerant flowing through the refrigerant circuit 10 in the refrigerant quantity determination operation or the operating state quantity of the component device. By calculating the amount, the amount of refrigerant in the refrigerant circuit 10 can be calculated.

Since this step S12 is repeated until the condition for determining whether or not the refrigerant amount is appropriate in step S13, which will be described later, is satisfied, the additional charging of the refrigerant is started and the power is completed until the power is completed. Using the relational expression for each part, the amount of operating state force when the refrigerant is charged is calculated. More specifically, the refrigerant amount Mo in the outdoor unit 2 and the refrigerant amount Mr in each of the indoor units 4 and 5 necessary for determining whether or not the refrigerant amount is appropriate in step S 13 described later (that is, the refrigerant communication pipe 6, The refrigerant amount of each part of the refrigerant circuit 10 excluding 7 is calculated. Here, the refrigerant amount Mo in the outdoor unit 2 is calculated by adding the refrigerant amounts Mogl, Mc, Moll, Mol2, Mog2, Mob, and Mcomp of each part in the outdoor unit 2 described above.

[0053] In this way, by the control unit 8 functioning as a 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 automatic refrigerant charging operation. Then, the process of step S12 is performed.

(Step S13: Judgment of appropriateness of refrigerant quantity)

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 filled in the refrigerant circuit 10 after the additional charging of the refrigerant cannot be defined as the refrigerant amount of the refrigerant circuit 10 as a whole. . However, outdoor unit 2 and indoor units 4, 5 If we focus only on that (i.e., 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 can be known in advance by testing and detailed simulation. The amount is stored in advance in the memory of the control unit 8 as the charging target value Ms, and the operating state quantity force of the refrigerant flowing in the refrigerant circuit 10 or the component device in the refrigerant automatic charging operation is also calculated using the above-described relational expression. Refrigerant amount value obtained by adding refrigerant amount Mo of unit 2 and refrigerant amounts Mr of indoor units 4 and 5 Until this filling target value Ms is reached, additional charging of the refrigerant may be performed. 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 amounts Mr of the indoor units 4 and 5 in the automatic refrigerant charging operation has reached the charging target value Ms. This determination is a process for determining whether or not the amount of refrigerant charged in the refrigerant circuit 10 by additional charging of the refrigerant is appropriate.

[0054] Then, in step S13, the additional charging of the refrigerant in which 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 is completed. If not, the process of step S13 is repeated until the filling target value Ms is reached. In addition, 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 the refrigerant automatic Step S1 as the filling operation process is completed.

In the refrigerant amount determination operation described above, as the additional charging of the refrigerant into the refrigerant circuit 10 progresses, the degree of supercooling SCo mainly at the outlet of the outdoor heat exchanger 23 tends to increase, resulting in outdoor heat exchange. Since the refrigerant amount Mc in the chamber 23 increases and the refrigerant amount in other parts tends to be kept almost constant, the charging target value Ms is set to the value of the outdoor unit 2 that is not the outdoor unit 2 and the indoor units 4 and 5. Set as a value corresponding only to the refrigerant amount Mo, or set as a value corresponding to the refrigerant amount Mc of the outdoor heat exchanger 23, and perform additional charging of the refrigerant until the charging target value Ms is reached. Also good.

[0055] In this manner, the refrigerant amount determination unit functions to determine whether or not the refrigerant amount in the refrigerant circuit 10 in the refrigerant amount determination operation of the automatic refrigerant charging operation is appropriate (that is, whether or not the charging target value Ms has been reached). The control unit 8 performs the process of step S13.

(Step S2: Pipe volume judgment operation) When the above-described automatic refrigerant charging operation in step SI is completed, the process proceeds to the pipe volume determination operation in step S2. In the pipe volume determination operation, the control unit 8 performs the processing from step S21 to step S25 shown in FIG. Here, FIG. 7 is a flow chart of the pipe volume judgment operation.

(Steps S21 and S22: Pipe volume judgment operation and volume calculation for liquid refrigerant communication pipe) In step S21, the indoor unit 100% operation and condensation are performed in the same manner as the refrigerant amount judgment operation in step S11 in the above-described automatic refrigerant charging operation. Perform pipe volume judgment operation for liquid refrigerant communication pipe 6 including pressure control, liquid pipe temperature control, superheat control and evaporation pressure control. Here, the refrigerant temperature at the outlet of the main refrigerant circuit of the subcooler 25 in the liquid pipe temperature control is set as the first target value Tlpsl, and the refrigerant amount judgment operation is performed with the first target value Tlpsl. The stable state is the first state (see the refrigeration cycle indicated by the line including the broken line in Fig. 8). FIG. 8 is a Mollier diagram showing the refrigeration cycle of the air conditioner 1 in the pipe volume determination operation for the liquid refrigerant communication pipe.

Next, from the first state where the refrigerant temperature T lp at the outlet of the main refrigerant circuit side of the subcooler 25 in the liquid pipe temperature control is stabilized at the first target value Tlpsl, other equipment control, that is, condensation pressure control, The conditions of superheat degree control and evaporation pressure control are not changed (that is, without changing the superheat degree target value SHrs and low pressure target value Tes), and the liquid pipe temperature target value Tips is different from the first target value Tlpsl. 2 Change to the target value Tlps2 to achieve a stable second state (see the refrigeration cycle indicated by the solid line in Fig. 8). In the present embodiment, the second target value Tips 2 is a temperature higher than the first target value Tlpsl.

Thus, since the density of the refrigerant in the liquid refrigerant communication pipe 6 is reduced by changing from the stable state in the first state to the second state, the refrigerant amount Mlp in the liquid refrigerant communication pipe part B3 in the second state Will decrease compared to the amount of refrigerant in the first state. Then, the refrigerant decreased from the liquid refrigerant communication pipe part B3 moves to the other part of the refrigerant circuit 10. More specifically, as described above, the equipment control conditions other than the liquid pipe temperature control are not changed, so that the refrigerant amount Mogl in the high pressure gas pipe E and the refrigerant in the low pressure gas pipe H Amount Mog2, refrigerant amount Mgp in gas refrigerant communication pipe part G and refrigerant quantity Mcomp in compressor part J are kept almost constant, liquid refrigerant communication pipe part B The refrigerant reduced from 3 moves to the condenser part A, the high temperature liquid pipe part Bl, the low temperature liquid pipe part B2, the indoor unit part F, and the binos circuit part I. That is, the refrigerant amount Mc in the condenser part A, the refrigerant amount Moll 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 refrigerant reduced from the liquid refrigerant communication pipe part B3 As a result, the refrigerant amount Mr and the refrigerant amount Mob in the bypass circuit section I increase.

[0057] The control as described above is performed by the control unit 8 (more specifically, a chamber functioning as a pipe volume determination operation control means for performing a pipe volume determination operation for calculating the volume Mlp of the liquid refrigerant communication pipe 6. This is performed as the processing of step S21 by the transmission line 8a) connecting the inner control units 47, 57, the outdoor control unit 37, and the control units 37, 47, 57.

Next, in step S22, the liquid cooling medium is utilized by utilizing the phenomenon that the refrigerant is decreased from the liquid refrigerant communication pipe section B3 and moves to the other part of the refrigerant circuit 10 due to the change from the first state to the second state. Calculate the volume Vlp of connecting pipe 6.

First, the calculation formula 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 section 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 each part between the first and second states If the increase / decrease amount of the refrigerant is A Mc, Δ Μο11, Δ Μο12, A Mr, and Δ Mob (here, the refrigerant amount Mogl, the refrigerant amount Mog2 and the refrigerant amount Mgp are kept almost constant, they are omitted), the refrigerant increase / decrease The quantity Δ Mlp is, for example,

Δ Mlp = — (Δ Mc + Δ Moll + Δ Μο12 + Δ Mr + Δ Mob)

It is possible to calculate the functional force. Then, by dividing the value of ΔMlp by the refrigerant density change Δpip 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. it can. Note that although the calculation result of the refrigerant increase / decrease amount ΔMlp is hardly affected, the refrigerant amount Mogl and the refrigerant amount Mog2 may be included in the above-described functional expression.

[0058] Vlp = Δ Mlp / Δ lp

A Mc, Δ Μο11, Δ Μο12, A Mr, and A Mob are used to calculate the refrigerant amount in the first state and the refrigerant amount in the second state using the relational expressions for each part of the refrigerant circuit 10 described above. In addition, the amount of refrigerant in the second state is subtracted from the amount of refrigerant in the first state. The density change amount Δlp is obtained by calculating the refrigerant density at the outlet of the subcooler 25 in the first state and the refrigerant density at the outlet of the subcooler 25 in the second state. Refrigerant density force in two states Obtained by subtracting the refrigerant density in the first 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 operating state quantity of the component equipment using the arithmetic expression as described above.

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 Tlpsl in the first state, and the refrigerant in the liquid refrigerant communication pipe section B2 is changed. The amount of refrigerant in the other part is increased by moving the part to the other part, and the volume Vlp of the increased force liquid refrigerant communication pipe 6 is calculated. However, the second target value Tlps2 in the second state is Change the state so that the temperature is lower than the first target value Tlpsl in 1 state, and move the refrigerant from the other part to the liquid refrigerant communication pipe part B3 to reduce the amount of refrigerant in the other part, From this decrease, the volume Vlp of the liquid refrigerant communication pipe 6 may be calculated.

Thus, the volume Vlp of the liquid refrigerant communication pipe 6 is calculated from the refrigerant flowing in the refrigerant circuit 10 in the pipe volume determination operation for the liquid refrigerant communication pipe 6 or the operating state quantity of the component equipment. Pipe for the liquid refrigerant communication pipe The process of step S22 is performed by the control unit 8 functioning as a volume calculation means.

[0060] (Steps S23, S24: Pipe volume determination operation and volume calculation for gas refrigerant communication pipe) After the completion of the above Steps S21 and S22, in Step S23, all indoor units are operated, condensation pressure control, liquid Pipe volume judgment operation for gas refrigerant communication pipe 7 including pipe temperature control, superheat control and evaporation pressure control is performed. 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 Pesl, and the state in which the refrigerant amount determination operation is stable at the first target value Pesl is set as the first state. (See the refrigeration cycle indicated by the line including the dashed line in Figure 9). FIG. 9 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, the low pressure target value Pes of the suction pressure Ps of the compressor 21 in the evaporation pressure control is the first value. From the first state, which is stable at the standard value Pesl, the conditions for other equipment control, that is, liquid pipe temperature control, condensing pressure control and superheat degree control are not changed (ie, liquid pipe temperature target value Tips and superheat degree Without changing the target value SHrs), the low pressure target value Pes is changed to the second target value Pes2, which is different from the first target value Pesl, to achieve a stable second state (the refrigeration shown only by the solid line in FIG. 9). See cycle). In the present embodiment, the second target value Pes2 is a pressure lower than the first target value Pesl.

[0061] In this way, by changing from the stable state in the first state to the second state, the density of the refrigerant in the gas refrigerant communication pipe 7 is reduced, so the gas refrigerant communication pipe part in the second state The refrigerant amount Mgp of G is reduced compared to the refrigerant amount in the first state. Then, the refrigerant decreased from the gas refrigerant communication pipe part G moves to the other part of the refrigerant circuit 10. More specifically, as described above, the device control conditions other than the evaporation pressure control are changed, so that the refrigerant amount Mogl in the high-pressure gas pipe section E, the high-temperature liquid pipe section Refrigerant amount Moll in B1, refrigerant amount Mol2 in low temperature liquid pipe B2 and liquid Refrigerant communication pipe part B3 Refrigerant quantity Mlp is kept almost constant and gas refrigerant communication pipe part H, condenser section A, indoor unit section F, bypass circuit section I and compressor section J. 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 bypass circuit part I by the amount of refrigerant reduced from the gas refrigerant communication pipe part G The refrigerant amount Mob in the compressor and the refrigerant amount Mcomp in the compressor part J will increase.

[0062] The control described above is performed by the control unit 8 (more specifically, indoor side) that functions as a pipe volume determination operation control means for performing a pipe volume determination operation for calculating the volume Vgp of the gas refrigerant communication pipe 7. This is performed as the process of step S23 by the control unit 47, 57, the outdoor control unit 37, and the transmission line 8a) connecting the control units 37, 47, 57.

Next, in step S24, by changing from the first state to the second state, the gas refrigerant communication piping part G force also uses the phenomenon that the refrigerant decreases and moves to the other part of the refrigerant circuit 10 to connect the gas refrigerant. Calculate the volume Vgp of pipe 7.

First, the calculation formula used to calculate the volume Vgp of the gas refrigerant communication pipe 7 will be described. From the piping volume judgment operation described above, from this gas refrigerant communication pipe section G The amount of refrigerant that has decreased and moved to other parts of the refrigerant circuit 10 is the refrigerant increase / decrease amount ΔMgp, and the amount of refrigerant increase / decrease between the first and second states is A Mc, A Mog2, A Mr, A Mob And A Mcomp (here, the refrigerant amount Mogl, the refrigerant amount Moll, the refrigerant amount Mol2 and the refrigerant amount Mlp are omitted because they are kept almost constant), the refrigerant increase / decrease amount ΔMgp is, for example,

A Mgp = — (A Mc + A Mog2 + A Mr + A Mob + A Mcomp) can be calculated. Then, by dividing the value of ΔMgp by the refrigerant density change Δp gp between the first and second states in the gas refrigerant communication pipe 7, the volume Vgp of the gas refrigerant communication pipe 7 is calculated. can do. It should be noted that the calculation result of the refrigerant increase / decrease amount ΔMgp is hardly affected, but the above-mentioned function formula may include the refrigerant amount Mogl, the refrigerant amount Moll, and the refrigerant amount Mol2.

A Mc, A Mog2, A Mr, A Mob, and A Mcomp calculate the refrigerant amount in the first state and the refrigerant amount in the second state using the relational expressions for each part of the refrigerant circuit 10 described above. Further, the amount of refrigerant in the second state is obtained by subtracting the amount of refrigerant in the first state, and the density change amount Δp gp is the amount of refrigerant on the suction side of the compressor 21 in the first state. It is obtained by calculating the average density of the density ps and the refrigerant density p eo at the outlets of the indoor heat exchangers 42 and 52, and 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 equipment in the first and second states using the above arithmetic expression.

[0064] In the present embodiment, the gas refrigerant communication pipe section is changed so that the second target value Pes2 in the second state is lower than the first target value Pesl in the first state and becomes a pressure. The amount of refrigerant in the other part is increased by moving the refrigerant of G to the other part, and this increased force also calculates the volume Vlp of the gas refrigerant communication pipe 7, but the second target in the second state Change the state so that the value Pes2 is higher than the first target value Pesl in the first state, and move the refrigerant from the other part to the gas refrigerant communication pipe part G. The volume Vlp of the gas refrigerant communication pipe 7 is calculated from this reduced amount. A little.

As described above, the pipe volume for the gas refrigerant communication pipe for calculating the volume Vgp of the gas refrigerant communication pipe 7 from the refrigerant flowing in the refrigerant circuit 10 in the pipe volume judgment 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 unit 8 functioning as a calculation means.

[0065] (Step S25: Determination of the Validity of the Pipe Volume Judgment Operation)

After the above steps S21 to S24 are completed, in step S25, whether or not the result of the pipe volume determination operation is appropriate, that is, the refrigerant communication pipes 6 and 7 calculated by the pipe volume calculation means. It is determined whether the volume of Vlp and Vgp is reasonable.

Specifically, as in the following inequality, judgment 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. To do.

ε 1 Vlp / Vgp ε 2

Here, ε 1 and ε 2 are values that can be varied based on the minimum value and the maximum value of the pipe volume ratio in a feasible combination of the outdoor unit and the indoor unit.

[0066] Then, when the volume ratio VlpZVgp satisfies the above numerical range, the processing of step S2 that is applied to the pipe volume determination operation is completed, and when the volume ratio VlpZVgp does not satisfy the above numerical range, The pipe volume determination operation and the volume calculation process in steps S21 to S24 are performed again.

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

In this 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 (step S23). S24), but the pipe volume judgment operation for the gas refrigerant communication pipe 7 may be performed first. [0067] Also, in the above-described step S25, when the result of the pipe volume determination operation in steps S21 to S24 is determined a plurality of times as inappropriate, or the volume of the refrigerant communication pipes 6 and 7 is more simply If it is desired to make a determination of Vlp or Vgp, although not shown in FIG. 7, for example, in step S25, after determining that the result of the pipe volume determination operation in steps S21 to S24 is not valid, the refrigerant communication is performed. Estimate the length of the refrigerant communication pipes 6 and 7 from the pressure loss in the pipes 6 and 7, and move to the process of calculating the volume Vlp and Vgp of the refrigerant communication pipes 6 and 7 from the estimated pipe length and the average volume ratio. Then, the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 may be obtained.

In the present embodiment, the length of the refrigerant communication pipes 6 and 7 has no information on the pipe diameter, etc. The pipe volume judgment operation is performed on the assumption that the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 are unknown. The force described for calculating the volume Vlp and Vgp of the refrigerant communication pipes 6 and 7 When the pipe volume calculation means inputs information such as the diameter of the refrigerant communication pipes 6 and 7, the refrigerant communication pipe If you have the function to calculate the volume Vlp and Vgp of 6 and 7, you can use this function together.

[0068] Further, without using the function of calculating the volume Vlp and Vgp of the refrigerant communication pipes 6 and 7 using the above-described pipe volume determination operation and the operation result, the length of the refrigerant communication pipes 6 and 7 is the pipe diameter. When using only the function to calculate the volume Vlp and Vgp of the refrigerant communication pipes 6 and 7 by inputting such information, the above-mentioned validity judgment means (step S25) is used to input the refrigerant If the length of the communication pipes 6 and 7 is sufficient, it may be determined whether or not the information such as 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 processing of step S31 and step S32 shown in FIG. Here, FIG. 10 is a flowchart of the initial refrigerant quantity detection operation.

[0069] (Step S31: Refrigerant Amount Determination Operation)

In step S31, the indoor unit 100% operation, condensing pressure control, liquid pipe temperature control, superheat degree control, The refrigerant quantity determination operation including the pressure generation pressure control is performed.

In this way, the control unit 8 functioning as the refrigerant quantity determination operation control means for performing 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, performs the step S. 31 processes are performed.

(Step S32: Calculation of refrigerant amount)

Next, the control unit 8 that functions as the refrigerant amount calculation means while performing the refrigerant amount determination operation described above, the refrigerant flowing from the refrigerant circuit 10 in the initial refrigerant amount determination operation in step S32 or the operation state amount of the component device is used. Calculate the amount of refrigerant in circuit 10. The amount of refrigerant in the refrigerant circuit 10 is calculated using a relational expression between the amount of refrigerant in each part of the refrigerant circuit 10 described above and the operating state amount of the refrigerant flowing through the refrigerant circuit 10 or the constituent devices. At this time, the volume 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 are calculated and known by the above-described pipe volume determination operation. Refrigerant communication pipes 6 and 7 volumes Vlp and Vgp are multiplied by the refrigerant density to calculate refrigerant amounts Mlp and Mgp in refrigerant communication pipes 6 and 7, and the refrigerant quantities in the other parts are calculated. By adding, the initial refrigerant amount of the entire refrigerant circuit 10 can be detected. This initial refrigerant quantity is used as a reference refrigerant quantity Mi for the refrigerant circuit 10 as a reference for determining the presence or absence of leakage from the refrigerant circuit 10 in the refrigerant leakage detection operation described later. Is stored in the memory of the control unit 8 as state quantity storage means. In this way, the control unit 8 that functions as a refrigerant amount calculating means that calculates the refrigerant amount in 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 constituent devices. Then, the process of step S32 is performed.

Next, the refrigerant leak detection operation mode will be described with reference to FIGS. 1, 3, 6, and 11. FIG. Here, FIG. 11 is a flowchart of the refrigerant leak detection operation mode.

In the present embodiment, it is detected periodically (for example, when it is not necessary to perform air conditioning during holidays, late at night, etc.) whether refrigerant has leaked from the refrigerant circuit 10 due to unforeseen causes. A case will be described as an example.

(Step S41: Refrigerant amount judgment operation) First, when a certain amount of time (for example, every six months to one year) has elapsed in the normal operation mode such as the cooling operation or the heating operation described above, the refrigerant leak detection operation mode is automatically or manually changed from the normal operation mode. In the same manner as the refrigerant quantity judgment operation in the initial refrigerant quantity detection operation, the refrigerant quantity judgment 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.

[0071] Note that this refrigerant quantity determination operation is performed for each refrigerant leakage detection operation. For example, if the condensation pressure Pc is different, the refrigerant leakage occurs! Even if the refrigerant temperature Tco fluctuates at the outlet of the outdoor heat exchanger 23 due to the difference in temperature, the temperature of the refrigerant in the liquid refrigerant communication pipe 6 is the same as the liquid pipe temperature. Will be kept.

In this way, the control unit 8 functioning as the refrigerant amount determination operation control means for performing 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, performs step S41. Is performed.

(Step S42: Calculation of refrigerant quantity)

Next, the control unit 8 that functions as the refrigerant quantity calculation means while performing the refrigerant quantity determination operation described above, the refrigerant from the operating state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device in the refrigerant leakage detection operation in step S42. Calculate the amount of refrigerant in circuit 10. 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 operation state quantity of the refrigerant flowing through the refrigerant circuit 10 or the component device. At this time, 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 are calculated by the above-described pipe volume determination operation as in the initial refrigerant amount determination operation. Therefore, the refrigerant volumes Mlp and Mgp in the refrigerant communication pipes 6 and 7 are calculated by multiplying the volumes Vlp and Vgp of the refrigerant communication pipes 6 and 7 by the density of the refrigerant. By adding the refrigerant amounts of the other parts, the refrigerant amount M of the entire refrigerant circuit 10 can be calculated.

[0072] Here, as described above, since the temperature T1 P of the refrigerant in the liquid refrigerant communication pipe 6 is kept constant at the same liquid pipe temperature target value Tips by the liquid pipe temperature control, the liquid refrigerant communication pipe section Refrigerant amount Mlp in B3 is an outdoor heat exchange regardless of the operating conditions of the refrigerant leak detection operation. Even when the temperature Tco of the refrigerant at the outlet of the vessel 23 fluctuates, it is kept constant.

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 operating state quantity of the component device in the refrigerant leakage detection operation causes the step S42. Is performed.

(Steps S43, S44: Judgment of appropriateness of refrigerant amount, warning display)

When the refrigerant leaks from the refrigerant circuit 10 to the outside, the amount of refrigerant in the refrigerant circuit 10 decreases. Then, the refrigerant amount M of the entire refrigerant circuit 10 calculated in step S42 described above is detected through the initial refrigerant amount detection operation in the case where refrigerant leakage from the refrigerant circuit 10 occurs. When the reference refrigerant amount MU is also small and no refrigerant leakage from the refrigerant circuit 10 occurs, the value is almost the same as the reference refrigerant amount Mi.

[0073] Utilizing this fact, in step S43, it is determined whether or not refrigerant has leaked. If it is determined in step S43 that no refrigerant leaks from the refrigerant circuit 10, the refrigerant leak detection operation mode is terminated.

On the other hand, if it is determined in step S43 that refrigerant has leaked from the refrigerant circuit 10, the process proceeds to step S44, and a warning is sent to the warning display unit 9 informing that the refrigerant has been detected. After the display, the refrigerant leak detection operation mode is terminated.

In this way, the refrigerant amount determination means for detecting the presence or absence of refrigerant leakage by determining whether or not the refrigerant amount in the refrigerant circuit 10 is appropriate while performing the refrigerant amount determination operation in the refrigerant leakage detection operation mode. The processing of steps S42 to S44 is performed by the control unit 8 that functions as one refrigerant leakage detection means.

[0074] As described above, in the air conditioner 1 of the present embodiment, the control unit 8 includes the refrigerant amount determination operation means, the refrigerant amount calculation means, the refrigerant amount determination means, the pipe volume determination operation means, the pipe volume calculation means, A refrigerant amount determination system for determining the suitability of the amount of refrigerant charged in the refrigerant circuit 10 by functioning as a validity determination unit and a state quantity storage unit 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, since the refrigerant is in contact with the oil upper surface of the refrigerating machine oil collected in the oil reservoir 71d formed in the compressor casing 71 of the compressor 21, the refrigerating machine oil near the oil upper surface is obtained. Since the refrigerant temperature approaches the temperature of the refrigerant, and the refrigeration oil near the wall surface of the compressor casing 71 forming the oil reservoir 71d approaches the temperature of the wall surface, that is, the ambient temperature outside the compressor 21, the oil reservoir 71d In the refrigeration oil accumulated in the tank, a temperature distribution corresponding to the temperature difference between the temperature of the refrigerant in contact with the oil upper surface and the ambient temperature outside the compressor 21 is generated.

[0075] However, the air conditioner 1 of the present embodiment is configured so that the maximum value of the temperature difference between the refrigerating machine oil inside the compressor 21 and the refrigerant in contact with the refrigerating machine oil is 50 ° C or less. The temperature distribution of the refrigerating machine oil inside the compressor 21 is generated. As a result, the refrigerant amount Mqo dissolved in the refrigeration oil inside the compressor 21 can be accurately grasped, so that the suitability of the refrigerant amount in the refrigerant circuit 10 can be determined with high accuracy.

More specifically, in the air conditioner 1 of the present embodiment, the refrigerant amount in the refrigerant circuit 10 can be calculated based on the refrigerant flowing through the refrigerant circuit 10 or the operating state quantity of the component equipment. On the basis of the calculated refrigerant quantity, the suitability of the refrigerant quantity in the refrigerant circuit 10 is determined, and the refrigerant or the component device that flows through the refrigerant circuit 10 when calculating the refrigerant quantity. As one of the operating state quantities of the compressor, the dissolved refrigerant quantity Mqo is calculated based on the temperature of the refrigerant in contact with the refrigeration oil inside the compressor 21 (here, the suction temperature Ts). Since the temperature distribution of the refrigerating machine oil inside the machine 21 is generated, the calculation error of the solubility of the refrigerant in the refrigerating machine oil inside the compressor 21 can be reduced. This makes it possible to accurately grasp the amount of refrigerant Mqo, and to accurately ascertain the amount of refrigerant that is calculated. Can be judged.

[0076] (4) Modification

In the embodiment described above, the temperature distribution of the refrigerating machine oil inside the compressor 21 is configured such that the maximum value of the temperature difference between the refrigerating machine oil inside the compressor 21 and the refrigerant in contact with the refrigerating machine oil is 50 ° C or less. Therefore, the temperature of the refrigerant in contact with the refrigeration oil inside the compressor 21 (here, the suction temperature Ts) is the temperature of the refrigeration oil accumulated in the oil reservoir 71d. Even if is used, the amount of refrigerant Mqo dissolved in the refrigeration machine oil inside the compressor 21 can be calculated with high accuracy. However, even in this case, there is some temperature distribution of the refrigerating machine oil inside the compressor 21, and it is desirable to calculate the dissolved refrigerant amount Mqo by further considering the influence of this temperature distribution.

Therefore, in this modification, the outdoor temperature Ta as the atmospheric temperature outside the compressor 21 that is the cause of the temperature distribution of the refrigeration oil inside the compressor 21 is also used for the calculation of the dissolved refrigerant amount Mqo. Specifically, as the temperature of the refrigerating machine oil (hereinafter referred to as Toil) required for calculating the solubility φ of the refrigerant in the refrigerating machine oil, the suction temperature Ts and the outdoor temperature are used instead of the suction temperature Ts in the above-described embodiment. The average temperature of the refrigeration oil inside the compressor 21 expressed as a function of the temperature Ta (ie Toil = f4 (Ts, Ta)) can be used (intake temperature Ts and outdoor temperature Ta in Fig. 12 and refrigeration oil). (Refer to the diagram showing the relationship between the temperature and Toil.) The relationship between T oil, suction temperature Ts, and outdoor temperature Ta may be a function equation using measurement data obtained experimentally in advance or may be a map. Good. In addition, depending on the installation position of the outdoor temperature sensor 36 that detects the outdoor temperature Ta, there is a possibility that a deviation may occur between the detected outdoor temperature Ta and the ambient temperature outside the actual compressor 21. In this case, instead of using the detected outdoor temperature Ta as it is, a value obtained by correcting the outdoor temperature Ta may be used as the ambient temperature outside the compressor 21. Here, as a method of correcting the outdoor temperature Ta, at least one of the operation state quantity of the component equipment, for example, the capacity obtained from the operation state of the air conditioner 1, the discharge pressure Pd, and the air volume Wo of the outdoor fan 28 is used. It is possible to correct by using.

In this modification, the amount of dissolved refrigerant Mq is compared with the case where the amount of dissolved refrigerant Mqo is calculated based on only the temperature of the refrigerant in contact with the refrigerating machine oil inside the compressor 21 as in the above embodiment! The calculation error of o can be further reduced. As a result, the amount of refrigerant to be calculated can be grasped more accurately, so that the suitability of the amount of refrigerant in the refrigerant circuit 10 can be determined with higher accuracy.

(5) Other embodiments

As mentioned above, although embodiment of this invention was described based on drawing, specific structure can be changed in the range which does not deviate from the summary of invention which is not restricted to these embodiment. Noh.

For example, in the above-described embodiment, an example in which the present invention is applied to an air conditioner capable of switching between cooling and heating has been described. May be applied. In the above-described embodiment, the example in which the present invention is applied to the air conditioner including one outdoor unit has been described. However, the present invention is not limited to this, and the air conditioner includes a plurality of outdoor units. The present invention may be applied to an apparatus.

Industrial applicability

By utilizing the present invention, it becomes possible to accurately grasp the amount of refrigerant dissolved in the refrigeration machine oil inside the compressor, and to determine the suitability of the amount of refrigerant in the refrigerant circuit with high accuracy.

Claims

The scope of the claims

[1] Refrigerant configured by connecting the compressor (21), the heat source side heat exchanger (23), the expansion mechanism (38, 41, 51), and the use side heat exchanger (42, 52) Circuit (10),

Based on the refrigerant flowing through the refrigerant circuit or the operating state quantity of the component device, and comprising refrigerant quantity determination means for judging the suitability of the refrigerant quantity in the refrigerant circuit,

The maximum value of the temperature difference between the refrigerating machine oil inside the compressor and the refrigerant in contact with the refrigerating machine oil is 50 ° C. or less.

Air conditioner (1).

[2] The compressor (21) has an oil reservoir (71d) capable of storing refrigerator oil therein,

The refrigerant is in contact with the oil upper surface of the refrigerating machine oil accumulated in the oil reservoir inside the compressor.

The air conditioner (1) according to claim 1.

[3] Based on the refrigerant flowing through the refrigerant circuit (10) or the operating state quantity of the component device, the refrigerant quantity in the refrigerant circuit including the dissolved refrigerant quantity that is the refrigerant quantity dissolved in the refrigeration machine oil is calculated. A refrigerant amount calculating means;

The refrigerant amount determining means determines whether the refrigerant amount in the refrigerant circuit is appropriate based on the refrigerant amount calculated by the refrigerant amount calculating means.

The air conditioner (1) according to claim 1 or 2.

[4] The air conditioner according to claim 3, wherein the refrigerant amount calculating means calculates the amount of the dissolved refrigerant based on an operating state amount including at least an ambient temperature outside the compressor (21). 1).