JP2008025939A - Heat source unit and air conditioning device comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat source unit constituting an air conditioning device comprising a plurality of sealed compressors and using carbon dioxide as a refrigerant. <P>SOLUTION: This heat source unit 2 constitutes a refrigerant circuit 10 using carbon dioxide as the refrigerant, by connecting use units 4, 5, and comprises the plurality of sealed compressors 21, 22 provided with a compressing element 62 and a compressor motor 63 driving the compressing element 62 in a casing 61, polyalkylene glycol as refrigerating machine oil, and a current negating device 95 for negating electric current leaked from the compressor motor 63. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat source unit and an air conditioner including the heat source unit, and more particularly, to a heat source unit constituting a refrigerant circuit that uses carbon dioxide as a refrigerant by connecting a utilization unit, and an air conditioner including the heat source unit.

  In a so-called separate type air conditioner that forms a refrigerant circuit by connecting a utilization unit and a heat source unit, a CFC refrigerant, HCFC refrigerant, or HFC refrigerant is used as a refrigerant enclosed in the refrigerant circuit. Has been. However, from the viewpoint of environmental problems, the use of natural refrigerants that have a small impact on the environment is also being investigated for separate air conditioners, and the use of carbon dioxide that is nonflammable and nontoxic is particularly promising. ing.

  In the above-described separate type air conditioner, when carbon dioxide is used as a refrigerant, it is desirable to use a highly viscous refrigerating machine oil in order to ensure lubrication in the compressor because the refrigeration cycle has a high pressure. As a refrigerating machine oil suitable for this, there is polyalkylene glycol (hereinafter referred to as PAG).

  On the other hand, since PAG has high conductivity, when the compressor built in the heat source unit is a hermetic compressor, the leakage current becomes large and unsuitable. However, when carbon dioxide is used as a refrigerant, Since a sealing property in the compressor is required as the refrigeration cycle is increased in pressure, it is desirable to use a hermetic compressor.

  In the heat source unit with a built-in hermetic compressor, if the PAG is used as refrigeration oil, the leakage current from the motor built in the compressor increases. The problem will arise. In particular, when configuring a large-capacity heat source unit that assumes that multiple units to be used are connected, multiple compressors are built into the unit, so the leakage current from the motor is excessive. As a result, driving may become difficult. For this reason, it is difficult to realize a heat source unit that includes a plurality of hermetic compressors and constitutes an air conditioner that uses carbon dioxide as a refrigerant.

  An object of the present invention is to realize a heat source unit that includes a plurality of hermetic compressors and constitutes an air conditioner that uses carbon dioxide as a refrigerant.

  A heat source unit according to a first aspect of the present invention is a heat source unit that constitutes a refrigerant circuit that uses carbon dioxide as a refrigerant by connecting a utilization unit, and includes a compression element and a motor that drives the compression element in a casing. Are arranged, a polyalkylene glycol as refrigerating machine oil, and a current canceling device that cancels the leakage current from the motor.

  In this heat source unit, when carbon dioxide is used as the refrigerant, lubrication within the compressor is ensured by using polyalkylene glycol (hereinafter referred to as PAG) as the refrigerating machine oil, and a plurality of compressors are hermetically sealed. By using the compressor, the sealing performance in the compressor can be ensured, and an increase in leakage current from the motor can be suppressed by providing a current canceling device. Thereby, a plurality of hermetic compressors are provided, and a heat source unit constituting an air conditioner that uses carbon dioxide as a refrigerant can be realized.

  A heat source unit according to a second aspect of the present invention is the heat source unit of the air conditioner according to the first aspect of the present invention, wherein an oil reservoir for storing refrigerator oil is formed in the casing. The motor is disposed so as not to be immersed in the refrigerating machine oil accumulated in the oil reservoir.

  In this heat source unit, since the motor is disposed so as not to be immersed in the refrigerating machine oil accumulated in the oil reservoir, an increase in leakage current from the motor can be further suppressed.

  A heat source unit according to a third aspect of the present invention is the heat source unit of the air conditioner according to the second aspect of the present invention, wherein the motor is disposed above the compression element.

  In this heat source unit, since the motor is arranged above the compression element, an increase in leakage current from the motor can be further suppressed.

  A heat source unit according to a fourth aspect of the present invention is the heat source unit of an air conditioner according to any one of the first to third aspects of the invention, wherein the compression element is integrated with the cylinder having the cylinder chamber formed therein, the roller and the roller. And a piston that divides the cylinder chamber into a suction chamber and a discharge chamber, and a bush that sandwiches the blade, and is configured to revolve in the cylinder chamber by a motor.

  In this heat source unit, the compression element constitutes a so-called swing compressor having a cylinder, a piston in which rollers and blades are integrally formed, and a bush. For this reason, this compression element is relatively small in friction loss and power loss as compared with other types of positive displacement compression elements, and is suitable for incorporating a plurality of small compressors in the unit. On the other hand, in this compression element, since the roller and the blade are integrally formed, sliding between the piston and the bush is large, and the piston is caused by high pressure by using carbon dioxide as a refrigerant. There is a tendency that problems such as an increase in sliding load and seizure between the bush and the bush are likely to occur. However, in this heat source unit, PAG is used as the refrigeration oil, and sufficient lubrication between the piston and the bush can be secured. It is possible to suppress the occurrence of problems such as an increase in sliding load and seizure between the piston and the bush, which are a concern due to the adoption of the swing compressor, while making it easy to be built in.

  A heat source unit according to a fifth aspect of the present invention is the heat source unit of the air conditioner according to any one of the first to fourth aspects of the present invention, further comprising an inverter device for controlling the motor, and the current canceling device is provided in the inverter device. Cancel the high frequency leakage current.

  In this heat source unit, since the motor built in the hermetic compressor is controlled by the inverter device, a high-frequency leakage current is generated due to the voltage output from the inverter device to the motor. For this reason, when a plurality of hermetic compressors are provided as in this heat source unit, the leakage current from the motor increases remarkably. However, since this heat source unit includes a current canceling device, an increase in leakage current due to this high-frequency leakage current can be suppressed. Accordingly, a plurality of hermetic compressors including a motor controlled by the inverter device are provided, and a heat source unit that constitutes an air conditioner that uses carbon dioxide as a refrigerant can be realized.

  An air conditioner according to a sixth aspect includes the heat source unit according to any one of the first to fifth aspects.

  Since this air conditioner includes the heat source unit according to any of the first to fifth inventions, a large capacity refrigerant circuit that uses carbon dioxide as a refrigerant is configured by connecting a plurality of utilization units. can do.

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

  In the first invention, a heat source unit that includes a plurality of hermetic compressors and constitutes an air conditioner using carbon dioxide as a refrigerant can be realized.

  In the second invention, an increase in leakage current from the motor can be further suppressed.

  In the third invention, an increase in leakage current from the motor can be further suppressed.

  In the fourth invention, the adoption of the swing compressor makes it easy to incorporate a plurality of compressors in the unit, while the increase in the sliding load between the piston and the bush, which is a concern due to the adoption of the swing compressor, The occurrence of problems such as burn-in can be suppressed.

  In the fifth invention, a plurality of hermetic compressors incorporating motors controlled by an inverter device are provided, and a heat source unit constituting an air conditioner using carbon dioxide as a refrigerant can be realized.

  In the sixth invention, a large-capacity refrigerant circuit using carbon dioxide as a refrigerant can be configured.

  Hereinafter, based on drawings, an embodiment of a heat source unit concerning the present invention and an air harmony device provided with the same is described.

(1) Configuration of air conditioner <Overall configuration of air conditioner>
FIG. 1 is a schematic configuration diagram of a heat source unit and an air conditioner 1 including the heat source unit according to an embodiment of the present invention. In the present embodiment, the air conditioning apparatus 1 is an apparatus used for indoor cooling, and mainly includes one heat source unit 2, a plurality of (here, two) use units 4 and 5, and a heat source unit. 2 is a so-called multi-type air conditioner provided with refrigerant communication pipes 6 and 7 that connect 2 and use units 4 and 5. And the refrigerant circuit 10 of the air conditioning apparatus 1 of this embodiment is comprised by connecting the heat source unit 2 and the utilization units 4 and 5 via the refrigerant | coolant communication pipes 6 and 7. FIG. And in the refrigerant circuit 10, carbon dioxide is enclosed as a refrigerant. For this reason, in the air conditioning apparatus 1 of the present embodiment, the refrigeration cycle operation is performed by compressing carbon dioxide as a refrigerant until the critical pressure or higher.

<Usage unit>
The utilization units 4 and 5 are connected to the heat source unit 2 via the refrigerant communication pipe 6 and the refrigerant communication pipe 7 and constitute a part of the refrigerant circuit 10.

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

  The usage unit 4 mainly has a usage-side refrigerant circuit 10 b that constitutes a part of the refrigerant circuit 10. The use side refrigerant circuit 10b mainly includes a use side expansion mechanism 41 that depressurizes the refrigerant and a use side heat exchanger 42.

  In the present embodiment, the use side expansion mechanism 41 is an electric expansion valve that adjusts the flow rate of the refrigerant flowing in the use side refrigerant circuit 10b, and one end of the use side expansion mechanism 41 is connected to the refrigerant communication pipe 6 and the other end is the use side. It is connected to the heat exchanger 42.

  In the present embodiment, the use side heat exchanger 42 is a heat exchanger that functions as a refrigerant heater. One end of the use side heat exchanger 42 is connected to the refrigerant communication tube 7, and the other end is connected to the use side expansion mechanism 41.

  In the present embodiment, the usage unit 4 includes an indoor fan 43 for supplying indoor air after sucking indoor air into the unit and exchanging heat, and flows through the indoor air and usage-side heat exchanger 42. It is possible to exchange heat with the refrigerant. The indoor fan 43 is rotationally driven by a fan motor 43a.

  Further, the usage unit 4 includes a usage-side control unit 44 that controls the operation of each unit constituting the usage unit 4. The usage-side control unit 44 includes a microcomputer, a memory, and the like provided for controlling the usage unit 4, and a remote controller (not shown) for operating the usage unit 4 individually. Control signals and the like can be exchanged between them, and control signals and the like can be exchanged with a heat source side control unit 28 (described later) of the heat source unit 2.

<Heat source unit>
The heat source unit 2 is connected to the usage units 4 and 5 via the refrigerant communication pipe 6 and the refrigerant communication pipe 7, and constitutes a refrigerant circuit 10 between the usage units 4 and 5.

  Next, the configuration of the heat source unit 2 will be described. The heat source unit 2 mainly has a heat source side refrigerant circuit 10 a that constitutes a part of the refrigerant circuit 10. The heat source side refrigerant circuit 10a mainly includes a plurality of (here, two) compressors 21 and 22, a heat source side heat exchanger 23, a heat source side expansion mechanism 24 as an expansion mechanism for depressurizing the refrigerant, and a closure. And valves 25 and 26.

  In the present embodiment, the heat source side heat exchanger 23 is a heat exchanger that functions as a refrigerant cooler. One end of the heat source side heat exchanger 23 is connected to the discharge side of the compressors 21 and 22, and the other end is connected to the heat source side expansion mechanism 24.

  In the present embodiment, the heat source side expansion mechanism 24 is an electric expansion valve, one end of which is connected to the other end of the heat source side heat exchanger 23 and the other end is connected to the closing valve 25.

  In this embodiment, the heat source unit 2 includes an outdoor fan 27 for sucking outdoor air into the unit, exchanging heat, and then discharging the air to the outside, and flows through the outdoor air and the heat source side heat exchanger 23. It is possible to exchange heat with the refrigerant. The outdoor fan 27 is rotationally driven by a fan motor 27a.

  The shut-off valves 25 and 26 are valves provided at connection ports with external devices and pipes (specifically, the refrigerant communication pipes 6 and 7). The closing valve 25 is connected to the heat source side expansion mechanism 24. The closing valve 26 is connected to the suction side of the compressors 21 and 22.

  The compressors 21 and 22 are compressors for compressing a low-pressure gas refrigerant to a critical pressure (the critical pressure of carbon dioxide is 7.38 MPa) or higher. In the present embodiment, the two compressors 21 and 22 are provided in the heat source unit 2, but the present invention is not limited to this, and there are three or more compressors depending on the number of connected units. They may be connected in parallel.

  Next, the structure of the compressors 21 and 22 is demonstrated using FIGS. Since the compressor 21 and the compressor 22 have the same configuration, only the configuration of the compressor 21 will be described here, and the configuration of the compressor 22 is the same as the reference numerals indicating the respective parts of the compressor 22. Description of each part is abbreviate | omitted as what is attached | subjected a code | symbol. Here, FIG. 2 is a schematic longitudinal sectional view of the compressor 21. FIG. 3 is a schematic cross-sectional view of the compressor 21 and corresponds to the AA cross-section of FIG. FIG. 4 is a schematic cross-sectional view of the compressor 21 and corresponds to a cross section taken along line BB in FIG.

  In this embodiment, the compressor 21 is a hermetic compressor in which a compression element 62 and a compressor motor 63 are incorporated in a casing 61 that is a vertical cylindrical container.

  The casing 61 has a substantially cylindrical body plate 61a, an upper end plate 61b welded and fixed to the upper end of the body plate 61a, and a lower end plate 61c welded and fixed to the lower end of the body plate 61a. And in this casing 61, the compression element 62 is mainly arrange | positioned at the lower part, and the compressor motor 63 is arrange | positioned above the compression element. The compression element 62 and the compressor motor 63 are connected by a crankshaft 64 that is disposed so as to extend in the vertical direction in the casing 61. In the present embodiment, an oil reservoir 61d is formed in the lower portion of the casing 61 to store the refrigerating machine oil necessary for lubricating the inside of the compressor 21 (particularly, the compression element 62). In consideration of using carbon dioxide as a refrigerant, polyalkylene glycol (hereinafter referred to as PAG) having high viscosity is used as the refrigerating machine oil.

  The compression element 62 is a compression element constituting a swing compressor. In the present embodiment, the compression element 62 mainly includes a crankshaft 64, a front head 65, a first compression element 66, an intermediate head 67, and a second compression element 68. And a rear head 69. Here, the first compression element 66 is disposed so as to be sandwiched between the front head 65 and the intermediate head 67 in the vertical direction, and mainly includes the first piston 70, the first bush 71, and the first cylinder 72. It consists of and. The second compression element 68 is arranged so as to be sandwiched between the intermediate head 67 and the rear head 69 in the vertical direction, and mainly includes the second piston 73, the second bush 74, and the second cylinder 75. It is configured. In the present embodiment, the front head 65, the first cylinder 72, the intermediate head 67, the second cylinder 75, and the rear head 69 are fastened and integrated by a plurality of bolts (not shown). In this embodiment, the compression element constituting the swing compressor is selected as the compression element 62 because the friction loss and the power loss are relatively small compared to other types of positive displacement compression elements, and the heat source unit 2 This is because it is suitable for incorporating a plurality of small compressors (here, two compressors 21 and 22).

  The first cylinder 72 has a cylinder hole 72a, a suction hole 72b, a discharge path 72c, and a blade accommodation hole 72d. The cylinder hole 72 a is a cylindrical hole that penetrates along the rotation axis O. The suction hole 72b penetrates from the outer peripheral surface 72e to the cylinder hole 72a. The discharge path 72c is formed by cutting out a part on the inner peripheral side of the cylindrical portion forming the cylinder hole 72a. The blade accommodation hole 72 d is a hole for accommodating a blade portion 70 b (described later) of the first piston 70, and penetrates along the plate thickness direction of the first cylinder 72. A portion of the blade accommodation hole 72 d on the rotation axis O side accommodates the first bush 71 and slides with the first bush 71. A first eccentric shaft portion 64a of the crankshaft 64 and a roller 70a (described later) of the first piston 70 are accommodated in the cylinder hole 72a of the first cylinder 72, and the first piston is accommodated in the blade accommodation hole 72d. In a state in which the blade portion 70b of 70 and the first bush 71 are accommodated, the discharge path 72c is sandwiched between the front head 65 and the intermediate head 67 so as to face the front head 65 side. As a result, a cylinder chamber 76 is formed in the first compression element 62. The cylinder chamber 76 includes a suction chamber 76a that communicates with the suction hole 72b by the first piston 70, and a discharge chamber 76b that communicates with the discharge passage 72c. It will be divided into.

  The first piston 70 includes a cylindrical roller 70a and a blade 70b that is formed integrally with the roller 70a and protrudes radially outward of the roller 70a. The roller 70 a is inserted into the cylinder hole 72 a of the first cylinder 72 while being fitted to the first eccentric shaft portion 64 a of the crankshaft 64. Accordingly, when the crankshaft 64 rotates, the roller 70a performs a revolving motion around the rotation axis O of the crankshaft 64. The blade 70b is accommodated in the blade accommodation hole 72d. As a result, the blade 70b swings and moves forward and backward along the longitudinal direction with respect to the first bush 71 and the blade accommodation hole 72d.

  The first bush 71 is a pair of substantially semi-cylindrical members, and is accommodated in the blade accommodation hole 72d so as to sandwich the blade 70b of the first piston 70.

  The front head 65 is a member that covers the discharge path 72 c side of the first cylinder 72 and is fitted to the casing 61. A bearing portion 65a is formed on the front head 65, and a crankshaft 64 is inserted into the bearing portion 65a. Further, the front head 65 is formed with an opening 65b for guiding the gas refrigerant flowing through the discharge passage 72c formed in the first cylinder 72 to a discharge pipe 85 (described later). The opening 65b is closed or opened by a discharge valve (not shown) for preventing the backflow of the gas refrigerant.

  The intermediate head 67 is a member that faces the front head 65 with the first cylinder 72 interposed therebetween, and covers the lower portion of the first cylinder 72. A bearing portion 67a is formed in the intermediate head 67, and a crankshaft 64 is inserted into the bearing portion 67a.

  Similar to the first cylinder 72, the second cylinder 75 is formed with a cylinder hole 75a, a suction hole 75b, a discharge passage 75c, and a blade accommodation hole 75d. The cylinder hole 75a is a cylindrical hole that penetrates along the rotation axis O. The suction hole 75b penetrates from the outer peripheral surface 75e to the cylinder hole 75a. The discharge path 75c is formed by cutting out a part of the inner peripheral side of the cylindrical portion forming the cylinder hole 75a. The blade accommodation hole 75 d is a hole for accommodating a blade portion 73 b (described later) of the second piston 73, and penetrates along the plate thickness direction of the second cylinder 75. A portion of the blade accommodation hole 75 d on the rotation axis O side accommodates the second bush 74 and slides with the second bush 74. A second eccentric shaft 64b of the crankshaft 64 and a roller 73a (described later) of the second piston 73 are accommodated in the cylinder hole 75a of the second cylinder 75, and a second piston is accommodated in the blade accommodation hole 75d. In a state in which the blade portion 73b of 73 and the second bush 74 are accommodated, the discharge path 75c is sandwiched between the rear head 69 and the intermediate head 67 so as to face the rear head 69 side. Thus, a cylinder chamber 77 is formed in the second compression element 68. The cylinder chamber 77 includes a suction chamber 77a that communicates with the suction hole 75b by the second piston 73, and a discharge chamber 77b that communicates with the discharge passage 75c. It will be divided into. The second eccentric shaft portion 64b and the first eccentric shaft portion 64a are provided with a phase difference of 180 degrees.

  Similar to the first piston 70, the second piston 73 has a cylindrical roller 73a and a blade 73b that is formed integrally with the roller 73a and protrudes radially outward of the roller 73a. The roller 73 a is inserted into the cylinder hole 75 a of the second cylinder 75 in a state of being fitted to the second eccentric shaft portion 64 b of the crankshaft 64. As a result, when the crankshaft 64 rotates, the roller 73a performs a revolving motion around the rotation axis O of the crankshaft 64. The blade 73b is accommodated in the blade accommodation hole 75d. As a result, the blade 73b swings and moves forward and backward along the longitudinal direction with respect to the second bush 74 and the blade accommodation hole 75d. As described above, since the second eccentric shaft portion 64b and the first eccentric shaft portion 64a are 180 degrees out of phase, for example, the blade 70b of the first piston 70 has a blade receiving hole 72d of the first cylinder 72. In this case, the blade 73b of the second piston 73 is inserted in the blade receiving hole 75d of the second cylinder 75 most shallowly.

  Similarly to the first bush 71, the second bush 74 is a pair of substantially semi-cylindrical members, and is accommodated in the blade accommodation hole 75d so as to sandwich the blade 73b of the second piston 73.

  The rear head 69 is a member that covers the discharge path 75 c side of the second cylinder 75 and is fitted to the casing 61. A bearing portion 69a is formed in the rear head 69, and a crankshaft 64 is inserted into the bearing portion 69a. Further, the rear head 69 is formed with an opening 69b for guiding the gas refrigerant flowing in through the discharge passage 75c formed in the second cylinder 75 to a discharge pipe 85 (described later). The opening 69b is closed or opened by a discharge valve (not shown) for preventing the backflow of the gas refrigerant.

  The crankshaft 64 is provided with the above-described eccentric shaft portions 64a and 64b at the lower portion thereof, and the upper portion where the eccentric shaft portions 64a and 64b are not provided is fixed to a rotor 80 (described later) of the compressor motor 63. Has been. The crankshaft 64 is formed with an oil passage 64c that opens to the oil reservoir 61d and communicates with the cylinder chambers 76 and 77. A pump element 78 is provided at the lower end of the oil passage 64c. The pump element 78 supplies the cylinder chambers 76 and 77 via the oil passage 64c accumulated in the oil reservoir 61d.

  In this embodiment, the compressor motor 63 is a DC motor, and mainly includes an annular stator 79 fixed to the inner surface of the casing 61, and a rotor that is rotatably accommodated with a slight gap inside the stator 79. 80. A copper wire is wound around the stator 79, and coil ends 79a are formed above and below. A crankshaft 64 is fixed at the center of the rotor 80 along the rotation axis O. The copper wire wound around the stator 79 of the compressor motor 63 is connected to a terminal 86 provided on the casing 61 and supplied with power. The casing 61 is grounded to a ground E (see FIGS. 6, 7 and 8) not shown in FIGS.

  The casing 61 is provided with first and second suction pipes 81 and 82 so as to penetrate the body plate 61a. One end of the first suction pipe 81 communicates with the suction hole 72 b of the first cylinder 72, and the other end communicates with an accumulator 83 attached to the outside of the casing 61. The second suction pipe 82 has one end communicating with the suction hole 75 b of the second cylinder 75 and the other end communicating with an accumulator 83 attached to the outside of the casing 61. The accumulator 83 is provided with a suction pipe 84. Further, the casing 61 is provided with a discharge pipe 85 so as to penetrate the upper end plate 61b.

  As described above, the compressors 21 and 22 are two-cylinder hermetic swing compressors having the two compression elements 66 and 68 constituting the swing compressor in the present embodiment. In the compressors 21 and 22, when the pistons 70 and 73 (more specifically, the rollers 70 a and 73 a) of the compression elements 66 and 68 are revolved in the cylinder chambers 76 and 77 by the compressor motor 63. The low-pressure gas refrigerant flows into the cylinder chambers 76 and 77 from the suction holes 72b and 75b through the suction pipe 84, the accumulator 83, and the suction pipes 81 and 82, and is compressed by the rollers 70a and 73a. . Then, the high-pressure gas refrigerant compressed by the roller 70 a of the first compression element 66 passes from the opening 65 b of the front head 65 to the space in the casing 61 outside the compression element 62 via the discharge path 72 c of the first cylinder 72. Discharged. Further, the high-pressure gas refrigerant compressed by the roller 73 a of the second compression element 68 is discharged from the opening 69 b of the rear head 69 to the space in the casing 61 outside the compression element 62 through the discharge path 75 c of the second cylinder 75. Is done. Further, the high-pressure gas refrigerant discharged from the first compression element 66 to the space in the casing 61 outside the compression element 62 and the high-pressure gas refrigerant discharged from the second compression element 68 to the space in the casing 61 outside the compression element 62. The gas refrigerant joins in the space in the casing 61 and is discharged from the discharge pipe 85.

  The heat source unit 2 includes a heat source side control unit 28 that controls the operation of each unit constituting the heat source unit 2. The heat source side control unit 28 includes a microcomputer, a memory, and the like provided for controlling the heat source unit 2, and is transmitted between the use side control units 44 and 54 of the use units 4 and 5. Control signals and the like can be exchanged via the line 8a. That is, the use side control units 44 and 54 and the heat source side control unit 28 constitute a control unit 8 as an operation control means for performing operation control of the air conditioner 1.

  As shown in FIG. 5, the control unit 8 is connected so that various devices and valves 21, 22, 27, 43, and 53 can be controlled. Here, FIG. 5 is a control block diagram of the air-conditioning apparatus 1 according to the present embodiment.

  Moreover, in this embodiment, the compressor motor 63 of each compressor 21 and 22 is controlled by the inverter apparatus 91, as FIG. 5 shows. For this reason, both the compressors 21 and 22 can change an operation capacity.

  Next, the inverter device 91 will be described with reference to FIG. Here, FIG. 6 is a schematic electric circuit diagram of an inverter device 91 including a current canceling device 95 (described later).

  The inverter device 91 mainly includes a rectifier circuit 92 and a switching circuit 93 connected to the output side of the rectifier circuit 92. The rectifier circuit 92 is connected to an AC power supply 94 and has a function of converting an AC voltage of the AC power supply 94 into a DC voltage. The switching circuit 93 has a function of converting the DC voltage supplied from the rectifier circuit 92 into a three-phase high-frequency voltage and outputting it to the compressor motor 63.

  On the other hand, the casing 61 of each compressor 21, 22 is connected to the ground E, and there is a stray capacitance C between the compressor motor 63 and the casing 61, but during operation of the compressor 21, 22. A zero-phase voltage is generated through the stray capacitance C, and a high-frequency leakage current i1 flows from the stray capacitance C to the ground E. The high-frequency leakage current i1 changes according to the conductivity of the refrigerant in the compressors 21 and 22 and the refrigerating machine oil. For this reason, when PAG with high electroconductivity is used as refrigerating machine oil like this embodiment, it exists in the tendency for the high frequency leakage current i1 to become large.

  Therefore, the inverter device 91 is further provided with a current canceling device 95 and a leakage current signal detector 96 in order to suppress an increase in the leakage current from the compressor motor 63 due to such a high-frequency leakage current i1. It has been. The leakage current signal detector 96 is for detecting the high-frequency leakage current i1, and is provided between the AC power supply 94 and the rectifier circuit 92 in FIG. The current cancellation device 95 is an amplification circuit that generates a cancellation current i2 having a waveform similar to the high-frequency leakage current i1 detected by the leakage current signal detector 96. The cancellation current i2 is generated between the rectifier circuit 92 and the switching circuit 93. It has a function to output to. Since the current canceling device 95 is also connected to the ground E, as a result, the canceling current i2 is canceled from the high-frequency leakage current i1, and the leakage current i3 flowing from the stray capacitance C to the ground E is reduced. Can do. In addition to the case where the leakage current signal detector 96 is provided between the AC power supply 94 and the rectifier circuit 92 as shown in FIG. 6, the switching circuit 93, the compressor motor 63, and the like as shown in FIG. Or between the rectifier circuit 92 and the switching circuit 93 as shown in FIG. Here, FIG. 7 and FIG. 8 are modifications of the schematic electric circuit diagram of the inverter device including the current canceling device 95.

<Refrigerant communication pipe>
The refrigerant communication pipes 6 and 7 are refrigerant pipes that are constructed on site when the air conditioner 1 is installed at the installation location.

  As described above, the use-side refrigerant circuits 10b and 10c, the heat source-side refrigerant circuit 10a including a plurality of (here, two) compressors 21 and 22, and the refrigerant communication pipes 6 and 7 are connected to each other. The refrigerant circuit 10 of the air-conditioning apparatus 1 that is used as carbon dioxide and uses PAG as refrigerating machine oil is configured. And the air conditioning apparatus 1 of this embodiment has each of the heat source unit 2 and the utilization units 4 and 5 by the control part 8 comprised from the utilization side control parts 44 and 54, the heat source side control part 28, and the transmission line 8a. The device is controlled to perform a cooling operation, that is, a refrigeration cycle operation in which the heat source side heat exchanger 23 functions as a refrigerant cooler and the use side heat exchangers 42 and 52 function as refrigerant heaters. Be able to.

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

<Overall operation>
First, when the stop valves 25 and 26 are fully opened and an operation command is issued from a remote controller or the like, the compressor motor 63 of the compressors 21 and 22, the fan motor 27 a of the outdoor fan 27, and the fan motor 43 a of the indoor fans 43 and 53. , 53a is activated. Then, the low-pressure gas refrigerant is sucked into the compressors 21 and 22 and compressed until the pressure becomes equal to or higher than the critical pressure, and becomes a high-pressure gas refrigerant.

  Thereafter, the high-pressure gas refrigerant discharged from the compressors 21 and 22 is merged and then sent to the heat source side heat exchanger 23 to be cooled by exchanging heat with the outdoor air supplied by the outdoor fan 27. . The high-pressure refrigerant cooled in the heat source side heat exchanger 23 is sent to the utilization units 4 and 5 via the heat source side expansion mechanism 24, the closing valve 25, and the refrigerant communication pipe 6. The high-pressure refrigerant sent to the utilization units 4 and 5 is decompressed by the utilization-side expansion mechanisms 41 and 51 to near the suction pressure of the compressor 21 (that is, the pressure of the low-pressure gas refrigerant described above), and the low-pressure gas is decompressed. After becoming a refrigerant in a liquid two-phase state, it is sent to each of the use side heat exchangers 42, 52. In each of the use side heat exchangers 42, 52, heat is exchanged with the indoor air to evaporate and lower the pressure. It becomes a gas refrigerant. The low-pressure gas refrigerant is sent to the heat source unit 2 through the refrigerant communication pipe 7 and is again sucked into the compressors 21 and 22 through the closing valve 26.

<Compressor operation>
Next, the operation of the compressors 21 and 22 during the above operation will be described in detail.

  In the compressors 21 and 22, the pistons 70 and 73 (more specifically, the rollers 70 a and 73 a) of the compression elements 66 and 68 are revolving in the cylinder chambers 76 and 77 by the compressor motor 63. The low-pressure gas refrigerant flowing into the cylinder chambers 76 and 77 from the suction holes 72b and 75b through the suction pipe 84, the accumulator 83, and the suction pipes 81 and 82 is compressed by the rollers 70a and 73a. Then, the high-pressure gas refrigerant compressed by the roller 70 a of the first compression element 66 passes from the opening 65 b of the front head 65 to the space in the casing 61 outside the compression element 62 via the discharge path 72 c of the first cylinder 72. It is being discharged. Further, the high-pressure gas refrigerant compressed by the roller 73 a of the second compression element 68 is discharged from the opening 69 b of the rear head 69 to the space in the casing 61 outside the compression element 62 through the discharge path 75 c of the second cylinder 75. Has been. Further, the high-pressure gas refrigerant discharged from the first compression element 66 to the space in the casing 61 outside the compression element 62 and the high-pressure gas refrigerant discharged from the second compression element 68 to the space in the casing 61 outside the compression element 62. The gas refrigerant joins in the space in the casing 61 and is discharged from the discharge pipe 85.

  At this time, the temperature of the refrigerant also increases with compression. However, when carbon dioxide is used as the refrigerant as in this embodiment, a CFC refrigerant, an HCFC refrigerant, or an HFC refrigerant is used. Since the difference between the suction pressure and the discharge pressure is larger than that in the case, the degree of the temperature rise is also large, and not only the discharge pressure but also the discharge temperature becomes high. On the other hand, in the swing compressor employed as the compressors 21 and 22 of the present embodiment, since the piston formed integrally with the roller and the blade is used as the compression element, the first piston 70 (more Specifically, sliding between the blade 70b) and the first bush 71 and between the second piston 73 (more specifically, the blade 73b) and the second bush 74 is large, and carbon dioxide is used as a refrigerant. Due to the high pressure due to use, problems such as an increase in sliding load between the piston and the bush and seizure tend to occur. However, in the present embodiment, a PAG having a high viscosity at high temperature is used as refrigeration oil, and the pump element 78 enters the cylinder chambers 76 and 77 from the oil reservoir 61d at the bottom of the casing 61 through the oil passage 64c. Just by supplying refrigerating machine oil and performing lubrication, between the first piston 70 (more specifically, the blade 70b) and the first bush 71 and the second piston 73 (more specifically, the blade 73b), Since lubrication with the second bush 74 can be performed, it is possible to suppress the occurrence of problems such as an increase in sliding load and seizure between the piston and the bush, which are concerned by the adoption of the swing compressor. It can be done.

  However, in this embodiment, the advantage that the lubrication in the compressors 21 and 22 can be secured by using the PAG as the refrigerating machine oil is obtained, but the conductivity of the PAG is high, and as in the present embodiment. In addition, since the compressor motor 63 incorporated in each of the compressors 21 and 22 is controlled by the inverter device 91, the inverter device 91 is provided. Therefore, the high frequency leakage current i1 due to the high frequency voltage output to the compressor motor 63 tends to increase.

  For this reason, in the heat source unit 2 of the present embodiment, the current canceling device 95 is provided in the inverter device 91, and the high-frequency leakage current i1 flowing from the stray capacitance C toward the ground E tends to increase. Finally, the leakage current i3 leaking from the ground E is prevented from increasing.

  Thereby, in this embodiment, lubrication in the compressors 21 and 22 is ensured by using PAG as refrigerating machine oil, and a compressor is used by using a hermetic compressor as the plurality of compressors 21 and 22. 21 and 22 can be secured, and the current canceling device 95 can be provided to suppress an increase in the leakage current i3 from the compressor motor 63.

  In addition, in the present embodiment, the compressor motor 63 is disposed so as not to be immersed in the refrigerating machine oil accumulated in the oil reservoir 61 d in the casing 61, and the compressor motor 63 is located above the compression element 62. Since it is arranged, the high-frequency leakage current i1 itself can be reduced, and an increase in the leakage current i3 from the compressor motor 63 can be further suppressed.

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

(A)
In the heat source unit 2 of the present embodiment, when carbon dioxide is used as a refrigerant, lubrication in the compressors 21 and 22 is ensured by using PAG as refrigeration oil, and as the plurality of compressors 21 and 22 By using the hermetic compressor, the sealing performance in the compressors 21 and 22 can be secured, and by providing the current canceling device 95, an increase in the leakage current i3 from the compressor motor 63 can be suppressed. As a result, a plurality of hermetic compressors are provided, and a heat source unit constituting an air conditioner that uses carbon dioxide as a refrigerant can be realized.

  And in the air conditioning apparatus 1 of this embodiment, since the heat source unit 2 as described above is provided, a large capacity refrigerant circuit that uses carbon dioxide as a refrigerant by connecting a plurality of utilization units 4 and 5. 10 can be configured.

(B)
In the heat source unit 2 of the present embodiment, the compressor motor 63 is disposed so as not to be immersed in the refrigerating machine oil accumulated in the oil reservoir 61d, and the compressor motor 63 is disposed above the compression element 62. Therefore, an increase in leakage current from the compressor motor can be further suppressed.

(C)
In the heat source unit 2 of the present embodiment, the compression element 62 includes cylinders 72 and 75, pistons 70 and 73 in which rollers 70 a and 73 a and blades 70 b and 73 b are integrally formed, and bushes 71 and 74. This constitutes a swing compressor. For this reason, this compression element 62 has a relatively small friction loss and power loss compared to other types of positive displacement compression elements, and a small compressor (here, the compressors 21 and 22) in the heat source unit 2. It is suitable for incorporating multiple. On the other hand, in the compression element 62, since the rollers 70a and 73a and the blades 70b and 73b are integrally formed, sliding between the pistons 70 and 73 and the bushes 71 and 74 is large, and carbon dioxide is converted into the refrigerant. As a result of the increased pressure due to the use, the problems such as an increase in sliding load between the pistons 70 and 73 and the bushes 71 and 74 and seizure tend to occur. However, in this heat source unit 2, PAG is used as the refrigeration oil, and sufficient lubrication between the pistons 70 and 73 and the bushes 71 and 74 can be ensured. While facilitating the incorporation of multiple compressors in the heat source unit, it is possible to suppress the occurrence of problems such as increased sliding load and seizure between the piston and bushing, which are a concern due to the adoption of a swing compressor. Can be done.

(D)
In the heat source unit 2 of the present embodiment, since the compressor motor 63 built in the compressors 21 and 22 that are hermetic compressors is controlled by the inverter device 91, the compressor motor 63 from the inverter device 91 is controlled. A high-frequency leakage current i1 is generated due to the voltage output to. For this reason, when the compressors 21 and 22 which are several hermetic compressors are provided like this heat source unit 2, the increase of the leakage current i3 from the compressor motor 63 becomes remarkable. However, since the heat source unit 2 includes the current canceling device 95, an increase in the high-frequency leakage current i1 can be suppressed. Accordingly, a plurality of hermetic compressors including a compressor motor controlled by an inverter device are provided, and a heat source unit constituting an air conditioner using carbon dioxide as a refrigerant can be realized. It has become.

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

  For example, in the above-described embodiment, the example in which the present invention is applied to the air conditioner 1 in which a plurality of usage units 4 are connected to one heat source unit 2 has been described. The present invention is applied to an air conditioner in which the utilization unit and the heat source unit are connected under various connection conditions, such as application of the present invention to an air conditioner in which a plurality of utilization units are connected to the heat source unit. You may apply.

  In the above-described embodiment, the example in which the present invention is applied to the air conditioner 1 that is a so-called cooling-only machine capable of performing the cooling operation has been described. However, the present invention is not limited to this, and the cooling operation and the heating operation are performed. The present invention having various modes of operation is applied to a cooling / heating switching machine capable of switching between and cooling, and a cooling / heating simultaneous machine capable of simultaneously performing cooling and heating operations. You may apply.

  If this invention is utilized, the heat source unit which comprises the several airtight compressor and comprises the air conditioning apparatus which uses a carbon dioxide as a refrigerant | coolant is realizable.

It is a schematic block diagram of the heat source unit concerning one Embodiment of this invention, and an air conditioning apparatus provided with the same. It is a schematic longitudinal cross-sectional view of a compressor. FIG. 3 is a schematic cross-sectional view of the compressor, corresponding to the AA cross-section of FIG. 2. FIG. 3 is a schematic cross-sectional view of the compressor, corresponding to a BB cross section of FIG. 2. It is a control block diagram of an air conditioning apparatus. It is a schematic electric circuit diagram of an inverter device including a current canceling device. It is a modification of the schematic electric circuit diagram of the inverter apparatus including a current cancellation apparatus. It is a modification of the schematic electric circuit diagram of the inverter apparatus including a current cancellation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Heat source unit 4, 5 Utilization unit 10 Refrigerant circuit 21, 22 Compressor (sealed compressor)
61 Casing 61d Oil reservoir 62 Compression element 63 Compressor motor (motor)
70, 73 Piston 70a, 73a Roller 70b, 73b Blade 71, 74 Bush 72, 75 Cylinder 76, 77 Cylinder chamber 76a, 77a Suction chamber 76b, 77b Discharge chamber 91 Inverter device 95 Current canceling device

Claims (6)

A heat source unit that constitutes a refrigerant circuit (10) that uses carbon dioxide as a refrigerant by connecting the utilization units (4, 5),
A plurality of hermetic compressors (21, 22) in which a compression element (62) and a motor (63) for driving the compression element are arranged in a casing (61);
Polyalkylene glycol as refrigerating machine oil,
A current canceling device (95) for canceling the leakage current from the motor;
A heat source unit (2) comprising: In the casing (61), an oil reservoir (61d) for storing the refrigerator oil is formed,
The motor (63) is disposed so as not to be immersed in the refrigerating machine oil accumulated in the oil reservoir.
The heat source unit (2) according to claim 1.   The heat source unit (2) according to claim 2, wherein the motor (63) is arranged above the compression element (62).   The compression element (62) includes a cylinder (72, 75) having a cylinder chamber (76, 77) formed therein, a roller (70a, 73a), and a blade (70b, 73b) formed integrally with the roller. A piston (70, 73) that divides the cylinder chamber into a suction chamber (76a, 77a) and a discharge chamber (76b, 77b), and a bush (71, 74) that sandwiches the blade, The heat source unit (1) according to any one of claims 1 to 3, wherein the piston is configured to revolve in the cylinder chamber by a motor (63). An inverter device (91) for controlling the motor (63);
The current canceling device (95) cancels the high-frequency leakage current caused by the inverter device,
The heat source unit (2) according to any one of claims 1 to 4.   The air conditioning apparatus (1) provided with the heat-source unit (2) in any one of Claims 1-5.

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