JPH03172587A - Compressor equipment with wide capacity control range and air conditioning system using it - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a compressor device having a wide capacity control range, and
The present invention relates to capacity control of the refrigeration capacity of a refrigeration/air conditioning system using the same.

[Prior Art] As a method for controlling the capacity of a compressor in an air conditioner, there is a method of returning refrigerant gas in the middle of compression to the suction pressure side via a bypass passage, as described in JP-A-62-18979. . Furthermore, in recent years, a method has been used in which the rotational speed of the compressor is varied using a variable frequency inverter to vary the flow rate of gas discharged from the compressor.

[Problems to be Solved by the Invention] In the conventional technology described above, the compressor capacity control width is approximately 1:3 or 1:6, which is relatively small. However, when multiple indoor units are connected to one outdoor unit,
In the case of a multi-air conditioner in which each indoor unit operates independently, a compressor with a capacity control width of 1 m, which is wider than the capacity control width described above, is required. In addition, in the case of the capacity control method by controlling the rotation speed using an inverter, if you try to set the maximum rotation speed (the rotation speed of the compressor at the maximum value of the drive frequency) higher, the capacity of the drive inverter (unit: rkVA) becomes large, and if you want to install an air conditioner for a general building, there are constraints on power supply capacity (
This has the disadvantage of making it easier to be subject to restrictions such as contract power restrictions.

In order to solve the above-mentioned problems, it is an object of the present invention to provide a compressor capacity control and air conditioning system that expands the capacity control width and reduces the inverter capacity, and enables control that can realize high efficiency as an air conditioning system.

[Means for Solving the Problems] According to the present invention, there is provided a compressor device having a wide capacity control width according to each of claims 1 to 8, and claim 9 or claim 9 using the same. l.

A multi-air conditioning system as described is provided.

[Function] In the compressor device according to each of claims 1 to 6, capacity control in a low capacity range is performed by rotational speed control by inverter drive of the low capacity compressor, and mechanical control of the high capacity compressor is performed. Capacity control in a high capacity range is performed by the operation of the capacity control mechanism. The rated capacity of this high capacity compressor becomes the maximum capacity of this compressor device. On the other hand, in the compressor device according to claim 7 or 8, the capacity of one compressor is controlled by rotation speed control by an inverter drive in a low capacity range, and by the function of a mechanical capacity control mechanism in a high capacity range. Ru.

In either case, since driving by an inverter has a low capacity range, the capacity of the inverter can be small.

A multi-air conditioning system according to a ninth aspect of the present invention uses the above-mentioned compressor device and can meet the required capacity of the refrigeration cycle over a wide range. In particular, in the system according to claim 10, the defrosting time can be significantly shortened and simultaneous heating operation can be performed.

[Example] One embodiment of the present invention will be described with reference to FIGS. 1 to 3.

Figure 1 shows an overview of a multi-air conditioner as an air conditioning system for buildings, in which one outdoor unit 8 and multiple indoor units (for example, indoor units 10, 11, 12) are installed. 61 and 7 are connected to commercial power sources (for example, 3 It is a 501h or 607 frequency power supply with a phase of 200V. Compressor 3 is a high capacity compressor. The electric motor section of the compressor 3 is electrically connected to the power supply 1, and the compressor 3 is driven by the commercial power supply 1 (direct start-up, etc.), and the compressor 3
The number of revolutions is a constant number of revolutions. The capacity of the compressor 3 is, for example, about 201 cm, and it is equipped with a compressor structure with a bypass unloading function, and a screw type compressor is suitable. They are electrically connected via an inverter 6. Reference numerals 2 and 5 indicate power cables.

Therefore, by controlling the inverter 6, the drive frequency (IL
By controlling d), the rotation speed of the compressor 4 can be changed. 9 is an expansion valve.

Alphabetical symbols from A to M indicate refrigerant piping connecting each device of the refrigeration cycle.

The compressor 4 is a small capacity type variable speed compressor driven by an inverter 6, and for example, a scroll compressor with a maximum frequency of 51-P capacity is suitable.

In addition, Figure 1 shows the piping system during cooling operation.
The illustration of the four-way valve machine end as seen in the Bee 1 pump device is omitted.

An example of the operation of capacity control of the two compressors 3 and 4 when such a refrigeration cycle is configured will be explained based on FIGS. 2 and 3. In both figures, the horizontal axis represents the drive frequency (Hd), and the vertical axis represents the refrigerating capacity (in the figures, the ratio is expressed based on the minimum capacity).

First, the example shown in FIG. 2 will be explained below.

The drive frequency Hd of the small capacity compressor 4 is from 107 to 1501.
This is an inverter-driven compressor that can be varied up to 1z. In this case, the refrigerating capacity can be changed approximately according to the change in rotational speed, and the capacity control width is a capacity ratio of 1:10. In this case, the operation of the compressor 4 is as follows.

It changes in the range from point A to point B in the figure.

On the other hand, the high capacity compressor 3 is a constant speed compressor, and has a capacity control mechanism based on suction bypass control (bypass unloader mechanism 7 of a screw compressor shown in FIG. 5).
Mechanism similar to 9. If the compressor 3 is a scroll compressor, it is provided with a mechanism similar to the suction gas bypass mechanism 47 of the compressor 3 shown in FIG. For example, compressor 3
A compressor with a rated capacity of 20 fP (in the case of an air conditioner, 1 [P
It has a refrigeration capacity of about 3,000 kcal/hr. ), 25% unload (partial load)
If this is possible, as shown in Fig. 2, the compressor 3
This means that the capacity can be controlled from the 51-P class to the 201P class. That is, the compressor 3 becomes a variable capacity compressor with a capacity control width of 1:4, and the range of operating points when capacity is controlled is from point C to point D in the figure.

By creating a multi-air conditioner system using the compressors 3 and 4 in combination, it becomes possible to perform capacity control with a wide eJ control width of 1:40.

As described above, by applying drive by the inverter to the compressor 4 on the small capacity side, the inverter capacity (compressor 4
When the capacity of the electric motor is 51P, the inverter capacity (approximately 6 kVA) can be made smaller than that of the conventional configuration. If you try to drive the high capacity compressor with an inverter,
Since the rated output of the motor is 20 IF, the inverter capacity is approximately 22 kVA. Therefore, the same 1
When trying to obtain a capacity control width of 40, the present invention, which allows the capacity of the inverter to be reduced, is more economical and effective.

The example illustrated in FIG. 2 described above is based on the small capacity compressor 4.
Match the inverter's maximum frequency capacity with the high-capacity compressor's lowest capacity (in this example, the capacity at 25% unload operation), and make one pair for the entire multi-air conditioning system. An example of operation is shown in which 40 continuous capacity controls are possible.

FIG. 3 shows the maximum driving frequency lid (max) of the compressor 4.
An example of capacity control operation when the commercial power frequency of the constant speed compressor 3 is set to 60 Hz is shown. That is, 51 at point B
('8 is accepted, point A (drive frequency 11d: 10) 1z
) discloses an operation example in which the capacity is 0.8:HP.

In this case, the compression 4a4 becomes # width on the capacity side of 1 to G. Therefore, the compressor capacity control method shown in FIG. 3 results in an air conditioning system having a capacity control width of 1:24.

Table 1 shows examples of combinations of compressor types that can be applied to the high capacity compressor 3 and the small capacity compressor 4.

The example explained in FIG. This corresponds to the first combination example.

Table 1 Next, an example corresponding to the third combination example in Table 1 will be described with reference to FIG. In this embodiment, the high capacity side compressor 3 is a constant speed scroll compressor driven at a commercial frequency, and the small capacity side compressor 4 is a variable speed scroll compressor driven at a variable frequency via an inverter. I am taking this as an opportunity. In FIG. 4, the same or corresponding parts as those in FIG. 1 are indicated by the same symbols.

As shown in FIG. 4, the recompressors 3 and 4 each have a scroll part (consisting of an orbiting scroll 71 and a fixed scroll 70) forming a compression element part in the upper part of the container, and an electric motor part 3.
This is a vertical hermetic scroll compressor with 6 placed at the bottom of the container. The inside of this container has a high-pressure chamber structure in a high-temperature, high-pressure atmosphere. The basic structure of this compressor is well known and does not require detailed explanation. The compressor 3 is equipped with a mechanical capacity control means 47 (in this case, an intake gas bypass mechanism). This means connects the refrigerant gas in the middle of compression in the compression chamber 37 to the bypass pipe 38 and the flow rate control 03g.
It is configured by forming a gas flow path that returns the gas to the suction piping side through the compressor 3, and by adjusting the amount of suction bypass, the amount of gas discharged from the compressor 3 can be adjusted. Figures 1 to 3
As explained in the example shown in the figure, the compressor 4 is in charge of capacity control operation in the low capacity range, and the compressor 3 is in charge of capacity control operation in the high capacity range. Accordingly, one of the compressors is operated.

In this system, the compressors 3 and 4 are basically not operated at the same time, but one of them is always operated. Therefore, in order to ensure sealing between the high pressure side pressure (discharge pressure) and the low pressure side pressure (suction pressure),
Solenoid on/off valves 50, 51, 52 for piping M, L, A, A'
．． It is equipped with 53. In addition, the oil 32 in the chamber of the recompressor
, 712, the oil equalizing pipe 61 and the pressure equalizing pipe 6
0 is connected between the surface compressors.

The embodiment of capacity control using two compressors has been described above, but next, an embodiment of capacity control using one compressor will be explained with reference to FIGS. 5 to 7. Here, a screw compressor 85 suitable for high-speed rotation of around 110,000 rpm is taken as an example. FIG. 52 is a schematic diagram of the screw compressor and its electrical system, and FIGS. 6 and 7 are explanatory diagrams of its capacity control. The gear speed increasing unit 75 is configured such that the gear speed increasing ratio can be changed by a gear switching operation. As shown in Figs. 6 and 7, capacity control in the low refrigeration capacity range is achieved by driving the electric motor 70 with the inverter 6 such that the drive frequency Hd ranges from a minimum of 107 to a maximum of 60 Hz of the commercial power supply frequency. Use the rotation speed control method. In this case, the rated output of the motor is 6 IF
The inverter capacity is sufficient. Capacity control in a high capacity range where the capacity is equivalent to 6) P or more is to drive the electric motor 70 at a commercial frequency 601 (z), and as shown in FIG. For example, from 350 Orpm when the commercial power frequency is 60, to 11050 which is 3 times faster.
At the same time, the bypass unloader means 79 performs capacity control while increasing the speed to around Orp. As a result, in the high capacity range, the capacity can be varied from, for example, 6 µPs to 24) Ps. As shown in FIG. 5, switching between the commercial power source and the inverter power source G to the electric motor section 70 is performed by a +4 inch switching section 71. As a matter of course, this switch changeover operation and the gear changeover operation (details not shown) of the gear speed increaser section 75 are performed in conjunction with the air conditioning load. In this way, the screw compressor 85
By using a single unit and combining inverter control, gear speed increase to speed up the screw rotor, and mechanical capacity control mechanism called bypass unloader means, a wide capacity control width of 1 to 24 as in this example can be achieved. Capacity control becomes possible. Furthermore, since air conditioning is performed with one compressor, the entire device (the entire system) can be simplified and miniaturized.

FIG. 8 is a refrigeration cycle diagram showing an embodiment in which the present invention is applied to a multi-air conditioning system as an example of a building air conditioning system. Parts that are the same as or correspond to those in the previously described embodiments are designated by the same reference numerals. As described above, the high-capacity compressor 3 with a mechanical capacity control mechanism driven by a commercial power source and the variable speed low-capacity compressor 4 driven by a commercial power source via an inverter 6 are usually u, Similarly, only one of them is operated. 201 is a four-way valve, which is an electrically operated valve for switching the refrigerant flow during heating operation and cooling operation.

FIG. 8 shows a state in which the heating operation is being switched. The air conditioning control unit 205 takes in room temperature information, other pressure information, and other necessary information from the temperature sensor 209 of each indoor unit, and has the role of controlling the air conditioner. and a microcomputer section. 8th
In the figure, broken lines 226 and 227 indicate electrical signal lines. In this embodiment, when it becomes necessary to defrost the outdoor unit 8 during heating operation, upon receiving a command from the air conditioning control section 205, the power supply switching section 20G switches the commercial power supply 1 to the compressor 3, respectively, as shown in the figure. and the inverter power supply 6 at the same time, and the surface compressors 3 and 4 are operated at the same time.

At the same time, compressor discharge pipe A and pipe: I! The solenoid valve 230 of the bypass pipe Y connected between the FC and the bypass pipe Y is opened, and the hollow gas refrigerant is sent from the surface compressor in the direction of the arrow through the bypass pipe Y. In this way, the two compressors 3 and 4 are operated at the same time only during defrosting operation, increasing the flow rate of the main stream and bypassing the air to the outdoor unit, thereby significantly shortening the defrosting operation time. At the same time, heating operation is also performed at the same time as defrosting operation. This can improve the comfort of air conditioning.

During defrosting operation, the discharge pressure is relatively low, so
Even if two compressors are operated simultaneously, the operating current will not exceed the current value during normal operation (meaning during heating operation and cooling operation), so it is possible to operate the two compressors simultaneously in parallel as described above. It is.

FIG. 9 shows a power switching circuit in the embodiment described in FIG. 8, which operates the power switching units 71 and 206 via transmission lines 226 and 228, respectively, based on commands from the air conditioning control unit 205. FIG. According to a command from the air conditioning control section 205, during normal operation, the switching section 71 switches the power supply to operate either the compressor 3 or 4 according to the refrigerating capacity (load 8 degrees) of the indoor units 10 to 12. Further, only during the defrosting operation, the power supply switching section 206 is operated so that the two compressors 3 and 4 can be operated simultaneously.

・I[i [Effects of invention According to the present invention, there is an effect similar to that of a sun.

(1) Compressor condition control width is 1:20 depending on refrigeration capacity etc.
to 40, which can be set larger than the conventional system.

This enables fine-tuned air conditioning and greatly improves comfort.

(2) Since it is possible to reduce the inverter capacity, it is possible to save costs (reduce costs), simplify and downsize the air conditioning system, and also reduce contract power.

(3) Even in the case of a configuration using one compressor, capacity control over a wide range is possible, and the entire device (system) can be simplified and downsized.

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention, with Fig. 1 being a configuration diagram of a refrigeration cycle equipped with two compressors, Figs. Figure 4 shows an example in which two scroll compressors are used together with a vertical cross-sectional view of a surface compressor, and Figure 5 shows a wide capacity control range with one screw compressor. Figures 6 and 7 are explanatory diagrams for explaining the capacity control method of the embodiment, and Figure 8 shows how two compressors are operated simultaneously during defrosting of the outdoor unit. FIG. 9 is a schematic diagram of a power supply switching circuit used in the above system. 3... High capacity compressor 4... Low capacity compressor 6.
...Inverter 8...Outdoor unit 10.11,1
2...Indoor unit 47...Mechanical capacity control means (1 other person)

Claims (1)

[Claims] 1. A low capacity compressor with a variable rotation speed driven by a variable frequency inverter and a high capacity compressor with a constant rotation speed having a mechanical capacity control mechanism are combined in parallel, and A compressor device having a wide capacity control range, characterized in that capacity control operation is performed by the low capacity compressor, and capacity control operation in a high capacity range is performed by the high capacity compressor. 2. A compressor device with a wide capacity control width according to claim 1, wherein the high capacity compressor is a screw compressor, and the low capacity compressor is a scroll compressor. 3. A compressor device with a wide capacity control range according to claim 1, wherein both the high capacity compressor and the low capacity compressor are scroll compressors. 4. A compressor device having a wide capacity control width according to claim 1, 2 or 3, wherein the capacity at the highest inverter frequency of the low capacity compressor and the lowest capacity of the high capacity compressor match. 5. The high capacity compressor is driven by a constant frequency power supply,
Claims 1 and 2, wherein a maximum frequency of a variable frequency inverter that drives the low capacity compressor matches the constant frequency.
, 3 or 4, the compressor device having a wide capacity control width. 6. A compressor device with a wide capacity control width according to claim 5, wherein the constant frequency is a commercial frequency. 7 In the low capacity range, the capacity is controlled by rotational speed control driven by a variable frequency inverter, and in the high capacity range, the compressor is driven by a commercial frequency power source and capacity is controlled by a mechanical capacity control mechanism. A compressor device with a wide capacity control range. 8. The mechanical capacity control mechanism includes a variable speed increasing gear mechanism and/or a variable speed increasing gear ratio provided between the electric motor section and the compressor section.
A compressor device having a wide capacity control range according to claim 7, wherein the compressor device is a suction gas bypass unloading mechanism provided for the compressor section. 9. In a multi-air conditioning system in which a refrigeration cycle is constituted by one outdoor unit equipped with a refrigerant compressor device and a plurality of indoor units, the refrigerant compressor device is the refrigerant compressor device according to any one of claims 1 to 8. A multi-air conditioning system characterized by being a compressor device having a wide capacity control range, and controlling the capacity of the compressor device according to the required capacity of a refrigeration cycle. 10 The compressor device is provided with the compressor device according to any one of claims 1 to 6, and a bypass flow path for bypassing the refrigerant gas discharged from the compressor device to the refrigerant flow path between the outdoor unit and the indoor unit, and a bypass flow path during normal operation. 10. The multi-air conditioning system according to claim 9, further comprising a valve that closes the bypass flow path, and when the outdoor unit is defrosted, the valve is opened and both the high-capacity and low-capacity compressors are operated simultaneously.