JP3837208B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner equipped with a variable capacity compressor and a constant capacity compressor on the heat source side, and realizes multi-stage capacity control while reducing energy consumption and the number of components. Related to technology.
[0002]
[Prior art]
In recent air conditioners, in order to prevent room temperature overshoot and hunting during cooling and heating, the mainstream is to perform capacity control on the heat source side (compressor) according to the capacity requirements on the use side (indoor heat exchanger). It has become. Many compressor capacity control methods convert the frequency of alternating current using an inverter device, and thereby linearly control the rotational speed of the compressor. According to this method, since the capacity of the compressor can be arbitrarily changed from 0 to the rated point, substantially complete air conditioning control can be realized. However, the inverter device has various problems such as energy loss due to frequency conversion is unavoidable, an undesirable electromagnetic wave is emitted to the environment, and a large device has a high device cost.
[0003]
Therefore, in Japanese Patent Application Laid-Open No. 8-247560 and the like, a variable capacity compressor (hereinafter referred to as “capacity control”) that performs capacity control by a power control mechanism or a refrigerant return circuit while using a constant speed compressor with a compression mechanism driven at a constant speed. And PC compressor) have been proposed. The power control mechanism has a valve device attached to a cylinder side wall or the like of the compression mechanism. By opening the valve device, for example, compression work in the first half of the compression stroke is not performed. The refrigerant return circuit, for example, provides a bypass pipe between the discharge-side refrigerant circuit and the suction-side refrigerant circuit of the compressor, and opens the shut-off valve interposed in the bypass pipe, whereby the refrigerant after compression Is partially circulated to the suction side refrigerant circuit.
[0004]
When a PC compressor and a normal constant speed compressor are combined, multistage capacity control can be performed by operating or stopping both compressors individually or by driving a power control mechanism or a refrigerant return circuit. . For example, the rated capacity of the PC compressor is 4 horsepower, the rated capacity of the constant speed compressor is 6 horsepower, the capacity reduction amount of the PC compressor by the power control mechanism is 2 horsepower, and the capacity reduction amount by the refrigerant return circuit is 1 horsepower Then, the ability can be switched every 1 horsepower (that is, 10 steps) within a range of 1 to 10 horsepower.
[0005]
[Problems to be solved by the invention]
By the way, when the refrigerant return circuit described above is opened, a part of the compressed refrigerant circulates to the suction side refrigerant circuit, so that the compressor performs useless compression work. For example, when the operation is performed with the capacity of 9 horsepower, the compression work of 1 horsepower is discarded by the refrigerant return circuit, but the energy consumption is substantially the same as when the operation is performed with the capacity of 10 horsepower. As a result, an energy loss equal to or greater than that in the case of using the inverter device occurs, which makes it difficult to adopt the PC compressor. In addition, it is considered that the capacity control is performed only by the power control mechanism without providing the refrigerant return circuit. In this case, however, the capacity switching is performed every 2 horsepower (that is, 5 stages) in the above-described compressor configuration. End up. Therefore, in an air conditioner, when the capacity requirement on the use side is small (for example, about 1 to 3 horsepower), room temperature overshoot and hunting are likely to occur, which impairs user comfort in the air-conditioned space. There is a fear.
[0006]
Therefore, the present inventors have developed a PC compressor that can perform four-stage capacity control on the compressor body, and by combining this with a normal constant speed compressor, An air conditioner with reduced use frequency of the return circuit has been realized. That is, a PC compressor whose capacity can be switched for every 1 horsepower within a range of 1 to 4 horsepower is manufactured, and this is combined with a constant speed compressor having a capacity of 6 horsepower, so that the same as the conventional apparatus described above. While performing the capacity control in stages, the refrigerant return circuit could be used only during 5-horsepower operation. As a result, the frequency of discarding the compression work is reduced and energy consumption is naturally reduced. However, this time, the refrigerant return circuit is used only at the time of 5 horsepower operation, so the refrigerant return circuit (bypass piping, shut-off valve, joint) Etc.) has a problem that the cost performance is remarkably deteriorated.
[0007]
The present invention has been made in view of the above situation, and an object thereof is to provide an air conditioner that realizes multi-stage capability control while reducing energy consumption and the number of components.
[0008]
[Means for Solving the Problems]
Therefore, in the first aspect of the present invention, the high-pressure refrigerant circuit has a constant capacity compressor and a variable capacity compressor capable of capacity control on the heat source side, and a power control mechanism for adjusting the capacity of the variable capacity compressor. An air conditioner driven by a high-pressure refrigerant gas that circulates inside and a low-pressure refrigerant gas that circulates inside a low-pressure refrigerant circuit, wherein the communication pipe connects the high-pressure refrigerant circuit and the low-pressure refrigerant circuit, and the communication pipe And a plurality of introduction pipes that lead the refrigerant gas in the communication pipe to the power control mechanism, and are connected to the communication pipe on the high-pressure refrigerant circuit side from the respective branch positions of the plurality of introduction pipes. and a plurality of high-pressure side shut-off valve, the communicating pipe low pressure side blocked interposed in the most the low-pressure refrigerant circuit side of the branch position of the inlet conduit located on the low pressure side of the inlet pipe of the plurality of If the order to adjust the capacity of the variable capacity type compressor in a plurality of stages, and a capacity control means for controlling driving on the basis of said plurality of high-pressure side shut-off valve and the low-pressure-side shut-off valve to a predetermined control law The variable capacity compressor is controlled in a plurality of stages by controlling refrigerant gas from the plurality of introduction pipes, and the capacity control means is configured to stop the variable capacity compressor and When it is necessary to reduce the capacity on the heat source side during operation of the compressor, the high-pressure side shut-off valve and the low-pressure side shut-off valve are simultaneously opened so that the communication pipe is a refrigerant return pipe. Suggest a thing.
[0009]
In the present invention, for example, when the capacity of the constant capacity type compressor is relatively larger than the maximum capacity of the variable capacity type compressor and the indoor capacity request is a value between the two capacities, the capacity control means The high-pressure side shut-off valve and the low-pressure side shut-off valve are simultaneously opened while operating only the mold compressor. Then, the high-pressure refrigerant circuit and the low-pressure refrigerant circuit are communicated with each other via the communication pipe, and a part of the capacity of the constant capacity compressor is discarded, thereby satisfying the indoor capacity requirement.
[0010]
According to a second aspect of the present invention, in the air conditioner according to the first aspect, there are approximately two stages in the variable capacity compressor between the capacity of the constant capacity compressor and the maximum capacity of the variable capacity compressor. There is a difference in capacity, and when the communication pipe is a refrigerant return pipe, a capacity decrease amount and a capacity increase / decrease amount per stage of the variable capacity compressor are approximately equal.
[0011]
In the present invention, the capacity control means appropriately controls the operation of the constant capacity type compressor and the variable capacity type compressor and the open / close control of the high-pressure side shut-off valve and the low-pressure side shut-off valve. It can be controlled in steps from the minimum value to the maximum value.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an air conditioning system including one outdoor unit 1 and a plurality of indoor units 2. In FIG. 1, a refrigeration cycle is shown by a solid line, and a control / signal system is shown by a one-dot chain line. It is shown.
[0013]
On the outdoor unit 1 side, first and second compressors 3 and 4, an electromagnetic four-way valve 5, an outdoor heat exchanger 6, an electric fan 7, an accumulator 8, an oil separator 9, and the like are installed. Moreover, the electric expansion valve 11, the indoor heat exchanger 12, the electric fan 13, etc. are installed in each indoor unit 2 side. Among these devices, those constituting the refrigeration cycle are connected by refrigerant pipes 21 to 36 that are provided for the circulation of gas refrigerant or liquid refrigerant. In the figure, reference numerals 15 and 16 denote check valves that prevent the refrigerant from flowing back to the compressors 3 and 4, and are interposed in the refrigerant pipes 21 and 22, respectively.
[0014]
In the case of the present embodiment, the refrigerant pipe 23 (high-pressure refrigerant circuit) and the refrigerant pipe 32 (low-pressure refrigerant circuit) are communicated with each other by a communication pipe 41, and further from the communication pipe 41 in order from the refrigerant pipe 23 side. The third introduction pipes 42 to 44 are branched. Each of the first to third introduction pipes 42 to 44 is connected to the first compressor 3 as a drive source of a power control mechanism described later. The communication pipe 41 is provided with normally closed first to third high-pressure side shut-off valves 45 to 47 from the refrigerant pipe 23 from the branch positions of the first to third introduction pipes 42 to 44, respectively. 3 A normally closed low-pressure side shut-off valve 48 is interposed from the refrigerant pipe 32 from the branch position of the introduction pipe 44. In the figure, reference numeral 49 denotes a capillary tube, which is interposed between the low pressure side shutoff valve 48 and the refrigerant pipe 32 in the communication pipe 41.
[0015]
In the outdoor unit 1, an outdoor control unit (hereinafter referred to as an outdoor ECU) 51 including an input / output interface, a ROM, a RAM, and the like is installed. The outdoor ECU 51 drives and controls the compressors 3 and 4, the four-way valve 5, the electric fan 7, and the shut-off valves 45 to 48 based on input information from a built-in control program and various sensors (not shown).
[0016]
On the other hand, in each indoor unit 2, an indoor control unit (hereinafter referred to as an indoor ECU) 53 including a CPU, an input / output interface, a ROM, a RAM, and the like is installed. The indoor side ECU 52 controls the drive of the electric expansion valve 11 and the electric fan 13 based on a built-in control program, input signals from a remote controller (not shown), various sensors, and the like, and communicates with the outdoor side ECU 51 via the bus line 55. Send and receive signals to and from each other.
[0017]
In the case of this embodiment, the first and second compressors 3 and 4 are both electric twin rotor type constant speed compressors having a pair of upper and lower rotary compression elements, and the rated output on the first compressor 3 side is 4 horsepower. The rated output on the second compressor 4 side is 6 horsepower. The 1st compressor 3 is a PC compressor provided with the power control mechanism, and can change an output for every 1 horsepower between 1-4 horsepower.
[0018]
Hereinafter, the structure and operation of the power control mechanism in the present embodiment will be described.
[0019]
The compression mechanism 61 of the first compressor 3 includes a pair of upper and lower cylinders 69 and 70 sandwiched between a main frame 65 and a bearing plate 67, as shown in FIG. A pair of upper and lower cylinder chambers 73 and 75 defined by the intermediate plate 71, and a pair of upper and lower rotors 77 and 79 that rotate eccentrically with a phase difference of 180 ° while being in sliding contact with the inner peripheral surfaces of both cylinder chambers 73 and 75. It is made up of. In the figure, 80 is a compressor casing.
[0020]
The power control mechanism 81 communicates both cylinder chambers 73 and 75 at three communicating portions (portions that are 90 ° and 180 ° out of phase with respect to vanes described later). The cylinders 69 and 70 and the intermediate plate 71 are connected to each other. A valve hole 83 penetrating the outer periphery of the valve in the vertical direction, a pair of upper and lower piston valves 85 and 86 slidably held in the valve hole 83, and urging the piston valves 85 and 86 away from each other. The valve spring (compression coil spring) 87 is a main component. In the intermediate plate 71, the inner diameter of the valve hole 83 is smaller than the outer diameter of the piston valves 85 and 86 so as to form stoppers for the piston valves 85 and 86. Further, the valve spring 87 is completely compressed when a high pressure (for example, 20% of the maximum discharge pressure of the first compressor 3) higher than a predetermined value acts on the pressure receiving surfaces of both piston valves 85 and 86. Is set.
[0021]
The valve hole 83 communicates with both the cylinder chambers 73 and 75 through a pair of communication holes 88 and 89 drilled in the vicinity of the intermediate plate 71. The cylinders 69 and 70 and the intermediate plate 71 have a refrigerant introduction hole 91 parallel to the valve hole 83, and gas refrigerant from the introduction pipe 42 (43, 44) is introduced into the refrigerant introduction hole 91. Is done. Further, the main frame 65 and the bearing plate 67 are respectively formed with communication recesses 93 and 94 that allow the valve hole 83 and the refrigerant introduction hole 91 to communicate with each other.
[0022]
When low-pressure refrigerant gas is introduced into the refrigerant introduction hole 91, both piston valves 85 and 86 are pressed against the end face of the main frame 65 or the bearing plate 67 by the spring force of the valve spring 87 as shown in FIG. . As a result, both the cylinder chambers 73 and 75 are communicated with each other via the communication holes 88 and 89, the valve hole 83, and the check valve 90, and the one cylinder chamber 75 (73) to the other cylinder chamber 73 (75). Gas refrigerant flows into the suction space. On the other hand, when high-pressure refrigerant gas is introduced into the refrigerant introduction hole 91, high pressure is applied to the pressure receiving surfaces of both piston valves 85 and 86, the valve spring 87 is compressed, and both piston valves 85 and 86 approach each other and become intermediate. It contacts the plate 71. As a result, the communication holes 88 and 89 are closed by the outer peripheral surfaces of both piston valves 85 and 86, and the cylinder chambers 73 and 75 are not communicated with each other.
[0023]
FIG. 4 is a schematic diagram showing the arrangement of the power control mechanism 81 with respect to the compression mechanism 61. As described above, the power control mechanism 81 is disposed at a portion shifted in phase by 90 ° and 180 ° with respect to the vane 95, and the first introduction pipe 42 is connected to the power control mechanism 81 on the discharge port 97 side. The second introduction pipe 43 is connected to the power control mechanism 81 connected to and opposed to the vane 95, and the third introduction pipe 44 is connected to the power control mechanism 81 on the suction port 98 side.
[0024]
In the present embodiment, when the power control mechanism 81 is operated, the outdoor side ECU 51 appropriately drives and controls the first to third high pressure side cutoff valves 45 to 47 and the low pressure side cutoff valve 48. For example, if the first to third high-pressure side shut-off valves 45 to 47 are opened (ON operation) and the low-pressure side shut-off valve 48 is closed (OFF operation), the high-pressure refrigerant gas in the refrigerant pipe 23 is changed to the first to the third. It is introduced into each power control mechanism 81 via the third introduction pipes 42 to 44, whereby all communication between the cylinder chambers 73, 75 is blocked, and the first compressor 3 is compressed by 4 horsepower during its operation. Will do the job. If the low-pressure side shut-off valve 48 is opened (ON operation) from this state, the low-pressure refrigerant gas in the refrigerant pipe 32 is introduced into the power control mechanism 81 on the suction port 98 side via the third introduction pipe 44. As a result, 3/4 of the communication between the cylinder chambers 73 and 75 is cut off, and the first compressor 3 performs a compression work of 3 horsepower during the operation.
[0025]
Further, if the third high-pressure side shut-off valve 47 is further opened (ON operation) from this state, the low-pressure refrigerant gas in the refrigerant pipe 32 is transferred to the power control mechanism 81 facing the vane 95 via the second introduction pipe 43. As a result, the communication between the cylinder chambers 73 and 75 is cut by half, and the first compressor 3 performs the compression work of 2 horsepower during the operation. If the second high-pressure side shut-off valve 47 is further opened (ON operation) from this state, the low-pressure refrigerant gas in the refrigerant pipe 32 passes through each of the power control mechanisms 81 via the first to third introduction pipes 42 to 44. As a result, the communication between the cylinder chambers 73 and 75 is cut off by a quarter, and the first compressor 3 performs a compression work of 1 horsepower during its operation.
[0026]
The outdoor side ECU 51 performs the operation control of the first and second compressors 3 and 4 and the drive control of the power control mechanism 81 as follows when the outdoor unit 1 generates a capacity of 1 to 10 horsepower. That is, if only the first compressor 3 is operated and the first to third high-pressure side shut-off valves 45 to 47 and the low-pressure side shut-off valve 48 are driven and controlled according to the procedure described above, it is between 1 to 4 horsepower. The ability for each horsepower can be obtained. Moreover, if only the 2nd compressor 4 is drive | operated, naturally the capability of 6 horsepower can be acquired. And if the 1st-3rd high pressure side shut-off valve 45-47 and the low pressure side shut-off valve 48 are drive-controlled while operating the 1st, 2nd compressors 3 and 4 simultaneously, it will be between 7-10 horsepower. Ability for each horsepower can be obtained.
[0027]
When generating the 5-horsepower capacity in the outdoor unit 1, the outdoor ECU 51 operates only the second compressor 4, and at the same time, the first to third high-pressure side shut-off valves 45 to 47 and the low-pressure side shut-off valve 48. Are all opened (ON operation). Then, the refrigerant pipe 23 and the refrigerant pipe 32 are communicated by the communication pipe 41, and the high-pressure refrigerant gas flowing through the refrigerant pipe 23 flows out to the refrigerant pipe 32 side, and one of the compression works performed by the second compressor 4. Department will be discarded. That is, when the first to third high-pressure side shut-off valves 45 to 47 and the low-pressure side shut-off valve 48 are all opened, the communication pipe 41 has the same function as the refrigerant return circuit in the conventional apparatus. is there. In addition, since the capillary tube 49 interposed in the communication pipe 41 is set so as to circulate a high-pressure gas refrigerant for 1 horsepower when the second compressor 4 is operated, the outdoor unit 1 has a capacity of 5 horsepower. Will occur. FIG. 5 is a table showing the relationship between the capacity of the outdoor unit 1 and the ON / OFF states of the first and second compressors 3 and 4 and the shutoff valves 45 to 48.
[0028]
As described above, in the air conditioning system of the present embodiment, the communication piping for the power control mechanism and the shut-off valve are made to function as the refrigerant return circuit. Therefore, a dedicated bypass pipe and a shut-off valve are provided in the refrigerant return circuit. It is no longer necessary, and it has been possible to simplify equipment configuration and reduce costs.
[0029]
Although description of specific embodiment is finished above, the aspect of the present invention is not limited to this embodiment. For example, in the above-described embodiment, the present invention is applied to an air conditioning system including one variable capacity compressor and a constant capacity compressor, but a plurality of constant capacity compressors are provided. You may apply to. In the above embodiment, the four-stage control power control mechanism is provided in the twin rotor type constant speed compressor. However, the capacity control by the power control mechanism may be three stages or less or five stages or more. You may use the thing provided with the compression mechanism more than a triple rotor as a machine. Further, regarding the structure of the power control mechanism, for example, various structures such as providing a communication pipe outside the compressor casing are conceivable, and other specific configurations in the refrigeration cycle also depart from the spirit of the present invention. Any change can be made as long as it is within the range.
[0030]
【The invention's effect】
As described above in detail, according to the first aspect of the invention, the heat source side has the constant capacity type compressor and the variable capacity type compressor whose capacity can be controlled, and the capacity adjustment of the variable capacity type compressor is performed. An air conditioner in which a power control mechanism to be driven is driven by a high-pressure refrigerant gas flowing in a high-pressure refrigerant circuit and a low-pressure refrigerant gas flowing in a low-pressure refrigerant circuit, the communication between the high-pressure refrigerant circuit and the low-pressure refrigerant circuit And a plurality of introduction pipes branching from the communication pipe and leading the refrigerant gas in the communication pipe to the power control mechanism, and the high pressure refrigerant circuit side from each branch position of the plurality of introduction pipes the communication pipe in a plurality of high-pressure side shut-off valve interposed in the communication pipe, in the low-pressure refrigerant circuit side of the branch position of the introduction pipe positioned closest to the low pressure side of the inlet pipe of the plurality of And the low-voltage side shut-off valve which is interposed, the order to adjust the capacity of the variable capacity type compressor in a plurality of stages, based on the said plurality of high-pressure side shut-off valve and the low-pressure-side shut-off valve to a predetermined control law drive Capacity control means for controlling, and the variable capacity compressor is controlled in a plurality of stages by control of refrigerant gas from the plurality of introduction pipes, and the capacity control means includes the variable capacity compression When it is necessary to reduce the capacity on the heat source side when the machine is stopped and the constant capacity compressor is operating, the high pressure side shut-off valve and the low pressure are set to make the communication pipe a refrigerant return pipe. Since the side shut-off valve is opened at the same time, it eliminates the need for a dedicated refrigerant return circuit, such as bypass piping and shut-off valve, while achieving multi-stage capacity control. Realization and cost reduction It can be.
[0031]
According to a second aspect of the present invention, in the air conditioner according to the first aspect, the variable capacity compressor is substantially between the capacity of the constant capacity compressor and the maximum capacity of the variable capacity compressor. Since there is a difference in capacity for two stages and the capacity reduction amount when the communication pipe is a refrigerant return pipe and the capacity increase / decrease quantity per stage of the variable capacity compressor is substantially equal, capacity control By appropriately controlling the operation of the constant capacity type compressor and the variable capacity type compressor and the open / close control of the high pressure side shutoff valve and the low pressure side shutoff valve, the heat source side capacity can be reduced from the minimum value to the maximum value. It becomes possible to control in stages.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of an air conditioning system according to the present invention.
FIG. 2 is a half-cut longitudinal sectional view showing the structure and operation of a power control mechanism.
FIG. 3 is a half-cut longitudinal sectional view showing the structure and operation of a power control mechanism.
FIG. 4 is a schematic diagram showing an arrangement of a power control mechanism with respect to a compression mechanism.
FIG. 5 is a table showing the relationship between the capacity of the outdoor unit and the ON / OFF states of the first and second compressors and the shutoff valves.
[Explanation of symbols]
1 Outdoor unit 2 Indoor unit 3 1st compressor (variable capacity type compressor)
4 Second compressor (constant capacity compressor)
23 Refrigerant piping (high-pressure refrigerant circuit)
32 Refrigerant piping (low pressure refrigerant circuit)
41 communication pipe 42 first communication pipe 43 second communication pipe 44 third communication pipe 45 first high pressure side shutoff valve 46 second high pressure side shutoff valve 47 third high pressure side shutoff valve 48 low pressure side shutoff valve 49 capillary tube 51 outdoor side ECU

Claims (2)

A high-capacity refrigerant gas and a low-pressure gas that have a constant-capacity compressor and a variable-capacity compressor whose capacity can be controlled on the heat source side, and a power control mechanism that adjusts the capacity of the variable-capacity compressor flows in the high-pressure refrigerant circuit. An air conditioner driven by low-pressure refrigerant gas flowing in the refrigerant circuit,
A communication pipe that connects the high-pressure refrigerant circuit and the low-pressure refrigerant circuit;
A plurality of introduction pipes branching from the communication pipe and guiding the refrigerant gas in the communication pipe to the power control mechanism;
A plurality of high-pressure side shut-off valves interposed in the communication pipe on the high-pressure refrigerant circuit side from the respective branch positions of the plurality of introduction pipes;
A low-pressure side shut-off valve interposed in the communication pipe on the low-pressure refrigerant circuit side from the branch position of the introduction pipe located on the lowest pressure side among the plurality of introduction pipes;
A capacity control means for driving and controlling the plurality of high-pressure side shut-off valves and the low-pressure side shut-off valves based on a predetermined control law in order to adjust the capacity of the variable capacity compressor in a plurality of stages ;
The variable capacity compressor is controlled in a plurality of stages by controlling refrigerant gas from the plurality of introduction pipes,
When the variable capacity type compressor is stopped and the constant capacity type compressor is operating, the capacity control means is configured to reduce the capacity on the heat source side when the variable capacity type compressor is in operation. Therefore, the air conditioner is characterized in that the high-pressure side shut-off valve and the low-pressure side shut-off valve are opened simultaneously.   When there is a difference in capacity of approximately two stages in the variable capacity compressor between the capacity of the constant capacity compressor and the maximum capacity of the variable capacity compressor, and the communication pipe is a refrigerant return pipe The air conditioner according to claim 1, wherein the capacity reduction amount of the variable capacity compressor is substantially equal to the capacity increase / decrease amount per stage of the variable capacity compressor.

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