WO2016152552A1

WO2016152552A1 - Air conditioning system control device, air conditioning system, air conditioning control program, and air conditioning system control method

Info

Publication number: WO2016152552A1
Application number: PCT/JP2016/057550
Authority: WO
Inventors: 隆博加藤
Original assignee: 三菱重工業株式会社
Priority date: 2015-03-26
Filing date: 2016-03-10
Publication date: 2016-09-29
Also published as: JP6495064B2; EP3260792A1; EP3260792B1; CN107614984A; ES2745753T3; JP2016183817A; EP3260792A4

Abstract

An air conditioning control device controls a multi-split air conditioning system so that the operating pressure of refrigerant remains constant regardless of the indoor load. This air conditioning control device controls the rotational speed of a compressor so that the operating pressure of the refrigerant reaches a predetermined target pressure, and then after this control, controls a pressure ratio, which is the ratio of the high pressure of the refrigerant to the low pressure of the refrigerant, so that compressor efficiency is at an operating point where the efficiency is improved. Thus, the air conditioning control device can reduce compressor power consumption and allow the compressor to operate more efficiently.

Description

Control device for air conditioning system, air conditioning system, control program for air conditioning system, and control method for air conditioning system

The present invention relates to a control device of an air conditioning system, an air conditioning system, a control program of the air conditioning system, and a control method of the air conditioning system.

For example, in a so-called multi-type air conditioning system, which is an air conditioning system in which a plurality of indoor units are connected to one outdoor unit, the operating pressure of the refrigerant is made constant regardless of the indoor load, and each load in the plurality of indoor units Some controls (hereinafter referred to as "pressure constant control") are performed to secure the necessary capacity according to the above.

Here, in Patent Document 1, one end is connected between the expansion valve and the indoor heat exchanger as a refrigeration cycle that supplies the air conditioning capacity according to the required operating capacity without reducing the compressor operating efficiency, The refrigerant circuit includes an injection circuit whose other end is connected to the compressor, and the number of rotations of the compressor falls within the rotation speed range of the down slope in the compressor performance curve, the gas refrigerant is injected into the compressor, and the rotation speed of the compressor is compressed. An air conditioning system is disclosed that does not inject the gas refrigerant into the compressor within the range of the upslope rotational speed in the machine performance curve.

Furthermore, control for adjusting the target pressure (hereinafter referred to as "energy saving control") may be performed in response to the decrease in the indoor load, as opposed to the pressure constant control. The case where the indoor load decreases is, for example, when the indoor suction temperature approaches the set temperature. The adjustment of the target pressure is performed by controlling the number of revolutions of the compressor, and for example, the target low pressure is increased during cooling and the target high pressure is reduced during heating to suppress the necessary capacity. Thereby, reduction of the power consumption of the compressor is realized.

JP, 2013-119957, A

However, the air conditioning system disclosed in Patent Document 1 requires an injection circuit, which complicates the structure of the refrigerant circuit.
In the energy saving control, by adjusting the target pressure, the compressor may be operated at an operating point deviated from the efficient operating point for the compressor.

The present invention has been made in view of such circumstances, and is a control device for an air conditioning system, an air conditioning system, and an air conditioning system that reduce power consumption of the compressor and enable the compressor to operate more efficiently. It is an object of the present invention to provide a control program for a control method of an air conditioning system.

In order to solve the above-mentioned subject, a control device of an air conditioning system of the present invention, an air conditioning system, a control program of an air conditioning system, and a control method of an air conditioning system adopt the following means.

A control device of an air conditioning system according to a first aspect of the present invention includes pressure control means for controlling the number of rotations of a compressor such that the operating pressure of the refrigerant becomes a predetermined target pressure, and control by the pressure control means. And pressure ratio control means for controlling a pressure ratio, which is a ratio of the high pressure to the low pressure of the refrigerant, so as to become an operating point to improve the efficiency of the compressor after that.

The control device of the air conditioning system according to the present configuration performs, for example, control to make the operating pressure of the refrigerant constant regardless of the indoor load.

Then, the number of rotations of the compressor is controlled by the pressure control means so that the operating pressure of the refrigerant becomes a predetermined target pressure. This reduces the power consumption.
However, the control by the pressure control means may cause the compressor to be operated at an operating point deviated from the efficient operating point for the compressor.

Therefore, after the control by the pressure control means, the pressure ratio control means controls the pressure ratio which is the ratio of the high pressure to the low pressure of the refrigerant so as to be an operating point for improving the efficiency of the compressor compared to that before. Ru.

Thus, the present configuration reduces the power consumption of the compressor and enables the compressor to be operated more efficiently.

In the first aspect, the pressure control unit may reduce the number of rotations of the compressor such that the operating pressure becomes the target pressure.

According to this configuration, the capacity of the air conditioning system is suppressed, and the power consumption of the air conditioning system is further reduced.

In the first aspect, the pressure ratio control means may control the pressure ratio without changing the rotational speed of the compressor.

According to this configuration, the pressure ratio is controlled without changing the number of revolutions of the compressor, that is, without performing control on the compressor, and the operating point of the compressor can be easily changed to a desired value.

In the first aspect, the pressure ratio control means may control the pressure ratio by controlling the rotational speed of a fan provided in the outdoor unit.

According to this configuration, the operating point of the compressor can be easily changed to a desired value.

In the first aspect, the pressure ratio control means may control the pressure ratio by controlling the opening degree of the expansion valve provided in the outdoor unit.

An air conditioning system according to a second aspect of the present invention includes an outdoor unit, an indoor unit, and the control device described above.

A control program of an air conditioning system according to a third aspect of the present invention is a computer comprising: pressure control means for controlling the number of rotations of a compressor such that the operating pressure of the refrigerant becomes a predetermined target pressure; Function as pressure ratio control means for controlling the pressure ratio which is the ratio of the high pressure to the low pressure of the refrigerant so as to become an operating point to improve the efficiency of the compressor compared to that before, after control by means Let

In a control method of an air conditioning system according to a fourth aspect of the present invention, there is provided a first step of controlling the number of revolutions of a compressor such that the operating pressure of the refrigerant becomes a predetermined target pressure; And a second step of controlling a pressure ratio, which is a ratio of the high pressure to the low pressure of the refrigerant, to become an operating point that improves the efficiency of the compressor compared to that of the former.

According to the present invention, the power consumption of the compressor can be reduced, and the compressor can be operated more efficiently.

It is a refrigerant circuit figure of the multi type air conditioning system concerning an embodiment of the present invention. It is a block diagram which shows the electric constitution of the air conditioner control device which concerns on embodiment of this invention. It is an efficiency map of the compressor concerning the embodiment of the present invention. It is a flow chart which shows the flow of the efficiency improvement control processing concerning the embodiment of the present invention. It is an efficiency map of the compressor concerning the embodiment of the present invention.

Hereinafter, an embodiment of a control device of an air conditioning system, an air conditioning system, a control program of an air conditioning system, and a control method of an air conditioning system according to the present invention will be described with reference to the drawings.

FIG. 1 is a refrigerant circuit diagram of a multi-type air conditioning system in which a plurality of indoor units are connected to a single outdoor unit according to an embodiment of the present invention.
In the multi-type air conditioning system 1, a plurality of

indoor units

3A and 3B are connected in parallel to one outdoor unit 2. The plurality of

indoor units

3A, 3B are connected in parallel with each other between the gas side pipe 4 connected to the outdoor unit 2 and the liquid side pipe 5 via the branching unit 6.

The outdoor unit 2 includes an inverter-driven compressor 10 for compressing a refrigerant, a four-way switching valve 12 for switching the circulation direction of the refrigerant, an outdoor heat exchanger 13 for heat exchange between the refrigerant and the outside air, and an outdoor heat exchanger 13 A supercooling coil 14 integrally formed, an outdoor expansion valve (EEVH) 15, a receiver 16 for storing liquid refrigerant, a subcooling heat exchanger 17 for supercooling the liquid refrigerant, and supercooling heat exchange A supercooling expansion valve (EEVSC) 18 for controlling the amount of refrigerant diverted to the compressor 17 and an accumulator for separating a liquid component from the refrigerant gas sucked into the compressor 10 and attracting only the gas component to the compressor 10 side A gas side operation valve 20 and a liquid side operation valve 21 are provided.

The above-described devices on the outdoor unit 2 side are sequentially connected via the refrigerant pipe 22 to constitute a known outdoor-side refrigerant circuit 23. Further, the outdoor unit 2 is provided with an outdoor fan 24 for blowing the outside air to the outdoor heat exchanger 13.

The gas side pipe 4 and the liquid side pipe 5 are refrigerant pipes connected to the gas side operation valve 20 and the liquid side operation valve 21 of the outdoor unit 2, and are connected to the outdoor unit 2 at the time of installation and construction at the site The pipe length is appropriately set in accordance with the distance between the plurality of

indoor units

3A and 3B. A plurality of branching devices 6 are provided in the middle of the gas side piping 4 and the liquid side piping 5, and an appropriate number of

indoor units

3A and 3B are connected via the branching devices 6. Thus, a closed refrigeration cycle (refrigerant circuit) 7 is configured.

The

indoor units

3A and 3B heat exchange the indoor air with the refrigerant, cool or heat them, and provide the indoor air conditioning with the indoor heat exchanger 30, the indoor expansion valve (EEVC) 31, and the indoor heat exchanger 30. An indoor fan 32 for circulating indoor air and an indoor controller 33 are provided, and are connected to the branching unit 6 via the branch

gas side pipes

4A, 4B and the branch

liquid side pipes

5A, 5B on the indoor side.

In the multi-type air conditioning system 1 described above, the cooling operation is performed as follows.
The high-temperature, high-pressure refrigerant gas compressed and discharged by the compressor 10 is circulated to the outdoor heat exchanger 13 by the four-way switching valve 12 and is heat exchanged with the outside air blown by the outdoor fan 24 by the outdoor heat exchanger 13 It is condensed and liquefied. The liquid refrigerant is further cooled by the subcooling coil 14, passes through the outdoor expansion valve 15, and is temporarily stored in the receiver 16.

The liquid refrigerant whose circulation amount has been adjusted by the receiver 16 is partially flowed from the liquid refrigerant piping in the process of being circulated through the liquid refrigerant piping side through the subcooling heat exchanger 17 and adiabatically expanded by the subcooling expansion valve 18 The heat is exchanged with the refrigerant to give a degree of subcooling. The liquid refrigerant is led from the outdoor unit 2 to the liquid side pipe 5 through the liquid side operation valve 21 and is branched to the branched

liquid side pipes

5A, 5B of the

indoor units

3A, 3B through the branching unit 6. .

The liquid refrigerant divided into the branched

liquid side pipes

5A, 5B flows into the

indoor units

3A, 3B, is adiabatically expanded by the indoor expansion valve 31, and flows into the indoor heat exchanger 30 as a gas-liquid two-phase flow. Ru. In the indoor heat exchanger 30, the indoor air and the refrigerant circulated by the indoor fan 32 exchange heat, and the indoor air is cooled and provided for indoor cooling. On the other hand, the refrigerant is gasified, passes through the branch

gas side pipes

4A, 4B, and reaches the branch 6, and is merged with the refrigerant gas from other indoor units by the gas side pipe 4.

The refrigerant gas joined in the gas side pipe 4 returns to the outdoor unit 2 again, passes through the gas side operation valve 20 and the four-way switching valve 12 and is joined with the refrigerant gas from the subcooling heat exchanger 17. Introduced to In the accumulator 19, the liquid contained in the refrigerant gas is separated, and only the gas is drawn into the compressor 10. The refrigerant is compressed again in the compressor 10, and the cooling operation is performed by repeating the above cycle.

On the other hand, the heating operation is performed as follows.
The high-temperature, high-pressure refrigerant gas compressed and discharged by the compressor 10 is circulated to the gas-side operation valve 20 via the four-way switching valve 12. The high pressure gas refrigerant is led from the outdoor unit 2 through the gas side operation valve 20 and the gas side pipe 4 and passes through the branching unit 6 and the branch

gas side pipes

4A and 4B on the indoor side to a plurality of

indoor units

3A and 3B. be introduced.

The high temperature / high pressure refrigerant gas introduced into the

indoor units

3A, 3B is heat exchanged with the indoor air circulated through the indoor fan 32 by the indoor heat exchanger 30, and the indoor air heated by this is blown out into the room It is served for heating. On the other hand, the refrigerant condensed and liquefied by the indoor heat exchanger 30 passes through the indoor expansion valve 31 and the branch

liquid side pipes

5A and 5B to reach the branch 6, and is merged with the refrigerant from the other indoor units. And return to the outdoor unit 2. During heating, in the

indoor units

3A and 3B, the degree of opening of the indoor expansion valve 31 is the indoor controller so that the refrigerant outlet temperature or the degree of refrigerant supercooling of the indoor heat exchanger 30 functioning as a condenser becomes the control target value. It is controlled via 33.

The refrigerant returned to the outdoor unit 2 passes through the liquid side operation valve 21 to reach the subcooling heat exchanger 17, and after being subcooled as in the case of cooling, flows into the receiver 16 and is temporarily stored. Thus, the circulation amount is adjusted. The liquid refrigerant is supplied to the outdoor expansion valve 15 and adiabatically expanded, and then flows into the outdoor heat exchanger 13 through the subcooling coil 14.

In the outdoor heat exchanger 13, the refrigerant exchanges heat with the outside air blown from the outdoor fan 24, and the refrigerant absorbs heat from the outside air to be vaporized and gasified. The refrigerant is introduced from the outdoor heat exchanger 13 through the four-way switching valve 12 to the refrigerant gas from the subcooling heat exchanger 17 and then introduced into the accumulator 19. In the accumulator 19, the liquid contained in the refrigerant gas is separated, and only the gas is drawn into the compressor 10 and compressed again in the compressor 10. The heating operation is performed by repeating the above cycle.

FIG. 2 is a block diagram showing an electrical configuration of the air conditioner control device 40 that controls the multi-type air conditioning system 1 according to the present embodiment. In addition, in FIG. 2, the function regarding the pressure fixed control and pressure ratio control which mentions a detail later is shown.
The air conditioner control device 40 is configured of, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), a computer readable storage medium, and the like. Then, a series of processes for realizing various functions are stored in the form of a program, for example, in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing and arithmetic processing. Thus, various functions are realized. The program may be installed in advance in a ROM or other storage medium, may be provided as stored in a computer-readable storage medium, or may be distributed via a wired or wireless communication means. Etc. may be applied. The computer readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory or the like. Further, the air conditioner control device 40 is provided in the outdoor unit 2.

The air conditioner controller 40 includes a pressure control unit 42, a pressure ratio control unit 44, and a storage unit 46.

As an example, the pressure control unit 42 performs constant pressure control to keep the operating pressure of the refrigerant constant regardless of the indoor load. The constant pressure control secures the necessary capacity of the compressor 10 by controlling the rotational speed of the compressor 10 such that the operating pressure of the refrigerant becomes a predetermined target pressure.
More specifically, in the constant pressure control, when the initial number of revolutions of the compressor 10 is determined, the target pressure is set by the model capacity, the number of revolutions (operating frequency), etc. During heating (low pressure) and heating, the discharge pressure (high pressure) is detected as a pressure detection value by a pressure sensor. And pressure fixed control compares this target pressure and a pressure detection value, and controls the number of rotations of compressor 10. FIG. Specifically, constant pressure control reduces the rotational speed of the compressor 10 when target pressure> pressure detection value during cooling, and raises the rotational speed of the compressor 10 when target pressure <pressure detection value. . On the other hand, constant pressure control raises the rotational speed of the compressor 10 when the target pressure is higher than the detected pressure value during heating, and lowers the rotational speed of the compressor 10 when the target pressure is lower than the detected pressure value. When the target pressure = the pressure detection value, the rotational speed of the compressor 10 is constant, so that the suction pressure is constant during cooling and the discharge pressure is constant during heating.

The pressure ratio control unit 44 sets the pressure ratio (high pressure to high pressure to low pressure) of the refrigerant so as to be an operation point that improves the efficiency of the compressor 10 compared to that after the control by the pressure control unit 42. Control (hereinafter referred to as "pressure ratio control").

The storage unit 46 stores compressor efficiency distribution information indicating the efficiency distribution of the compressor 10 obtained from the rotational speed and pressure ratio of the compressor 10.
FIG. 3 is an efficiency map showing an example of compressor efficiency distribution information, in which the horizontal axis is the number of revolutions of the compressor 10, the vertical axis is the pressure ratio, and the efficiency of the compressor 10 is shown by a solid line Is represented. That is, the efficiency of the compressor 10 is higher as the center of the efficiency map shown in FIG. 3 (inner side of the contour line). The compressor efficiency distribution information is not limited to the efficiency map as shown in FIG. 3 but may be stored in the storage unit 46 in the form of a function or a table.

Next, constant pressure control and pressure ratio control executed by the air conditioner control device 40 according to the present embodiment will be described in detail. In the following description, constant pressure control and pressure ratio control are collectively referred to as high efficiency control.

As described above, the constant pressure control is to make the operating pressure of the refrigerant constant regardless of the indoor load. Furthermore, the constant pressure control according to the present embodiment, for example, reduces the rotational speed of the compressor 10 so that the pressure of the refrigerant reaches the newly adjusted target pressure when the indoor load decreases. Energy saving control to reduce the ability of

The decrease in indoor load is when the indoor suction temperature and the set temperature approach a predetermined range. When a plurality of indoor units 3 are connected as in the multi-type air conditioning system 1 according to the present embodiment, for example, the difference between the indoor suction temperature and the set temperature of half or more of the indoor units 3 is within 1 ° C. Indoor load is reduced.
Then, when the indoor load decreases during cooling, the pressure control unit 42 decreases the rotational speed of the compressor 10 by raising the target pressure (target low pressure) until then. On the other hand, when the indoor load decreases during heating, the pressure control unit 42 reduces the rotational speed of the compressor 10 by lowering the target pressure (target high pressure) until then.
The target pressure is adjusted stepwise, and in each case, the difference between the indoor suction temperature and the set temperature is detected. And if this difference becomes large, the capacity of the compressor 10 becomes insufficient with respect to the indoor load, so the adjustment of the target pressure ends.

The change of the operating point of the compressor 10 when the energy saving control according to the present embodiment is performed will be described with reference to FIG. 3.
The operating point indicated by point A is the operating point during normal control before the target pressure is adjusted, that is, before energy saving control is performed. And point B is an operating point after energy saving control is performed.

However, the operating point B of the energy saving control is not necessarily an efficient operating point for the compressor 10. In the example of FIG. 3, even if the rotation speed is the same as the operating point B, a region where the pressure ratio is high (for example, a region including the point C) is a more efficient operating point.

Therefore, by the pressure ratio control according to the present embodiment, an operating point (the point C in the example of FIG. 3 and hereinafter referred to as “optimum optimum operating point”) which improves the efficiency of the compressor 10 compared to that before. As such, the pressure ratio is controlled.

Table 1 shows the adjustment of the operating point of the compressor 10 during cooling and heating.

As shown in Table 1, at the time of cooling, pressure ratio control is performed by controlling the high pressure, and energy saving control is performed by controlling the low pressure. On the other hand, energy saving control is performed by controlling high pressure during heating, and pressure ratio control is performed by controlling low pressure. As described above, the control purpose is different between the high pressure and the low pressure of the refrigerant between the cooling time and the heating time.

And the pressure ratio control part 44 which concerns on this embodiment performs pressure ratio control by changing the rotation speed of the outdoor fan 24 as an example.
Specifically, when the pressure ratio after the energy saving control is lower than the efficiency optimum operating point, the rotational speed of the outdoor fan 24 is reduced. As a result, while the high pressure of the refrigerant rises during cooling, the low pressure of the refrigerant falls during heating. Therefore, the pressure ratio is increased, and the operating point approaches the efficiency optimum operating point.
On the other hand, when the pressure ratio after the energy saving control is higher than the efficiency optimum operating point, the rotational speed of the outdoor fan 24 is increased. As a result, while the high pressure of the refrigerant drops during cooling, the low pressure of the refrigerant rises during heating. Therefore, the pressure ratio is lowered, and the operating point approaches the efficiency optimum operating point.

Thus, pressure ratio control performs pressure ratio control without changing the rotation speed of the compressor 10. That is, the pressure ratio control is to control the pressure ratio without controlling the compressor 10, and it is easy to change the operating point of the compressor 10 to a desired value.

Further, the efficiency optimum operating point is, for example, predetermined as a pressure ratio that provides the best efficiency with respect to the rotational speed of the compressor 10, and may have a certain width with respect to the pressure ratio increase / decrease direction .

FIG. 4 is a flowchart showing the flow of the high efficiency control process executed by the air conditioner control device 40. A program (high efficiency control program) for executing this process is stored in advance in a predetermined area of the storage unit 46. It is memorized. Note that, before the high efficiency control process is performed, the air conditioner control device 40 performs constant pressure control (normal control) without energy saving control.

First, in step 100, it is determined whether or not the indoor load has decreased to a level at which the energy saving control can be started. If the determination is positive, the process proceeds to step 102. In the case of a negative determination, normal control is continued.

In step 102, normal control is ended, and setting is made to start energy saving control.

In the next step 104, the target pressure is adjusted to perform energy saving control. At the time of cooling, the target pressure (target low pressure) is increased, and at the time of heating, the target pressure (target high pressure) is decreased.

In the next step 106, it is determined whether or not the operating pressure matches the adjusted target pressure, and in the case of a positive determination, the process proceeds to step 110, and in the case of a negative determination, the process proceeds to step 108.

In step 108, the rotational speed of the compressor 10 is controlled so that the operating pressure matches the target pressure, and the process returns to step 106 to compare the operating pressure with the adjusted target pressure.
Specifically, when the low pressure is lower than the target low pressure during cooling, or when the high pressure is higher than the target high pressure during heating, the rotational speed of the compressor 10 is reduced. On the other hand, when the low pressure is higher than the target low pressure during cooling, or when the high pressure is lower than the target high pressure during heating, the rotational speed of the compressor 10 is increased.

In step 110, the efficiency optimum operating point is set according to the rotational speed of the compressor 10.

In the next step 112, it is determined whether the actual pressure ratio and the pressure ratio of the efficiency optimum operating point coincide with each other. If the determination is negative, the process proceeds to step 114. If the determination is affirmative, the process returns to step 106, and the energy saving control and the pressure ratio control are repeatedly continued.

In step 114, the rotational speed of the outdoor fan 24 is controlled so that the actual pressure ratio and the pressure ratio at the efficiency optimum operating point coincide with each other, and the process returns to step 112 again, and the pressure ratio at the actual pressure ratio and the efficiency optimum operating point Compare with.
Specifically, when the actual pressure ratio is lower than the pressure ratio at the efficiency optimum operating point, the number of rotations of the outdoor fan 24 is reduced. As a result, the high pressure is increased during cooling, the low pressure is decreased during heating, and the actual pressure ratio is increased. On the other hand, when the actual pressure ratio is higher than the pressure ratio at the efficiency optimum operating point, the rotation speed of the outdoor fan 24 is increased. As a result, the high pressure is lowered at the time of cooling, the low pressure is raised at the time of heating, and the actual pressure ratio is lowered.

As described above, the air conditioner control device 40 according to the present embodiment controls the number of rotations of the compressor 10 so that the operating pressure of the refrigerant becomes a predetermined target pressure, and after this control, the compression is performed. The pressure ratio, which is the ratio of the high pressure to the low pressure of the refrigerant, is controlled so as to be an operating point that improves the efficiency of the machine 10 compared to that of the past.
Thus, the air conditioner control device 40 reduces the power consumption of the compressor 10 and enables the compressor 10 to operate more efficiently.

As mentioned above, although this invention was demonstrated using the said embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the scope of the invention, and a form to which the changes or improvements are added is also included in the technical scope of the present invention. Also, the above embodiments may be combined as appropriate.

For example, in the above embodiment, although the embodiment has been described in which the number of rotations of the outdoor fan 24 is controlled to control the pressure ratio, the present invention is not limited to this. The opening degree of the expansion valve 15 may be controlled.
In the case of this mode, when the actual pressure ratio is lower than the pressure ratio at the efficiency optimum operating point in step 114 described above, the outdoor expansion valve 15 is throttled. As a result, the high pressure is increased during cooling, the low pressure is decreased during heating, and the actual pressure ratio is increased. On the other hand, when the actual pressure ratio is higher than the pressure ratio at the efficiency optimum operating point, the outdoor expansion valve 15 is opened. As a result, the high pressure is lowered at the time of cooling, the low pressure is raised at the time of heating, and the actual pressure ratio is lowered.

Further, in order to control the pressure ratio, both the rotation speed of the outdoor fan 24 and the opening degree of the outdoor expansion valve 15 may be controlled.
Also, instead of the outdoor expansion valve 15, a plurality of refrigerant circuits each provided with a throttle and a solenoid valve are provided in parallel, and by changing the flow path of the refrigerant by opening and closing the solenoid valve to change the throttle amount, pressure The ratio may be controlled.
Furthermore, the pressure ratio may be controlled by providing a plurality of outdoor heat exchangers 13 and changing the number (capacity) of the outdoor heat exchangers 13 through which the refrigerant flows.

In the above embodiment, although the embodiment has been described in which pressure ratio control is performed after energy saving control, the present invention is not limited to this, and pressure ratio control may be performed without energy saving control. Also good.
In the case of this embodiment, as shown in the example of FIG. 5, pressure ratio control may be performed after the normal control (operating point A) so that the operating point of the compressor 10 becomes the more efficient operating point C. .

In the above embodiment, although the air-conditioner controller 40 performs constant pressure control to keep the operating pressure of the refrigerant constant regardless of the indoor load, the present invention is not limited to this. Energy saving control may be performed without performing pressure constant control.

Further, in the above embodiment, although the embodiment has been described in which the energy saving control is performed when the indoor load decreases, the present invention is not limited to this, and the present invention is not limited to the case where the indoor load decreases. Even when the setting change by the user (administrator) of the air conditioning system 1, for example, the reduction setting of the rotational speed of the compressor 10, the change setting of the target pressure of the refrigerant, etc., energy saving control is performed. Good.

In addition, the flow of the high efficiency control process described in the above embodiment is also an example, and unnecessary steps may be deleted, new steps may be added, or the process order may be changed without departing from the scope of the present invention. You may

1 multi-type air conditioning system 2

outdoor unit

3A, 3B indoor unit 10 compressor 15 outdoor expansion valve 24 outdoor fan 40 air conditioner control device 42 pressure control unit 44 pressure ratio control unit

Claims

Pressure control means for controlling the number of revolutions of the compressor such that the operating pressure of the refrigerant becomes a predetermined target pressure;
Pressure ratio control means for controlling a pressure ratio which is a ratio of high pressure to low pressure of the refrigerant so as to become an operating point which improves the efficiency of the compressor after that by the pressure control means;
Control device for an air conditioning system comprising:
The control device according to claim 1, wherein the pressure control unit reduces the number of revolutions of the compressor so that the operating pressure becomes the target pressure.
The control device of an air conditioning system according to claim 1 or 2, wherein the pressure ratio control means controls the pressure ratio without changing the rotational speed of the compressor.
The control device of an air conditioning system according to any one of claims 1 to 3, wherein the pressure ratio control means controls the pressure ratio by controlling a rotational speed of a fan provided in an outdoor unit.
The control device of an air conditioning system according to any one of claims 1 to 4, wherein the pressure ratio control means controls the pressure ratio by controlling an opening degree of an expansion valve provided in an outdoor unit.
Outdoor unit,
Indoor unit,
A control device according to any one of claims 1 to 5;
An air conditioning system comprising
Computer,
Pressure control means for controlling the number of revolutions of the compressor such that the operating pressure of the refrigerant becomes a predetermined target pressure;
Pressure ratio control means for controlling a pressure ratio which is a ratio of high pressure to low pressure of the refrigerant so as to become an operating point which improves the efficiency of the compressor after that by the pressure control means;
Control program for air conditioning system to function.
A first step of controlling the number of revolutions of the compressor such that the operating pressure of the refrigerant reaches a predetermined target pressure;
A second step of controlling a pressure ratio, which is a ratio of a high pressure to a low pressure of the refrigerant, so as to become an operating point that improves the efficiency of the compressor after the control by the first step;
Method of controlling an air conditioning system having: