JP2016008743A - Air conditioning device and refrigerant distribution unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioning device which has little heat loss, and which can operate according to various loads.SOLUTION: An air conditioning device (1a) includes: an outdoor unit (2); a plurality of indoor units (4a, 4b); and a refrigerant distribution unit (3a). The outdoor unit (2) includes a first compressor (21). The refrigerant distribution unit (3a) includes: a second compressor (31); a second heat exchanger (32); a second decompression mechanism (34); and a flow passage switching mechanism (30). The flow passage switching mechanism (30) is a mechanism for switching between a first state and a second state. The second state is the state where the refrigerant discharged from the first compressor (21) is supplied to a part of the plurality of indoor units (4a, 4b) and returned to the first compressor (21), and also, the refrigerant discharged from the second compressor (31) is supplied to the other part of the plurality of indoor units (4a, 4b) and returned to the second compressor (31).

Description

  The present invention relates to an air conditioner and a refrigerant distribution unit to be incorporated in the air conditioner.

  Conventionally, an air conditioner that can efficiently supply a heat source with a simple configuration according to various loads has been proposed. For example, Patent Document 1 discloses an air conditioner 100 including a heat source unit 102, a relay unit 103, and a load unit 104 as shown in FIG.

  The air conditioner 100 includes a first cycle 105 in which a first medium circulates, a second cycle 106 in which a second medium circulates, and a third cycle 107 in which a second medium circulates. Here, the first medium is carbon dioxide, and the second medium is water or water obtained by adding an additive such as a preservative, or brine.

  The first cycle 105 includes a compressor 109, a flow path switch 110, a first heat exchanger 111, a first extension pipe 113, a first pressure reducing valve 114, a second heat exchanger 115, a second heat exchanger The pressure reducing valve 116, the third heat exchanger 117, the second extension pipe 118, the flow path switch 110, the accumulator 119, and the compressor 109 are connected in this order. The second cycle 106 includes a second heat exchanger 115, a first pump 121, a first branch path 140, a plurality of branch paths 108 a to 108 c, a first aggregation path 141, and a second heat exchanger 115. Are connected in this order. The third cycle 107 includes a third heat exchanger 117, a second pump 122, a second branch path 142, a plurality of branch paths 108a to 108c, a second aggregation path 143, and a third heat exchanger 117. Are connected in this order. The plurality of branch channels 108a to 108c include first channel switching valves 131a to 131c, flow rate adjusting valves 132a to 132c, third extension pipes 133a to 133c, indoor units 134a to 134c, and fourth extension pipes 136a to 136a. 136c and second flow path switching valves 137a to 137c.

  A case will be described in which the air-conditioning apparatus 1 is in a cooling operation in a state where the temperatures required from the indoor units 134a to 134c are different. In this case, in the first cycle 105, since the second heat exchanger 115 is connected upstream of the second pressure reducing valve 116, the temperature of the first medium passing through the second heat exchanger 115 is This is the temperature before the pressure is reduced by the second pressure reducing valve 116. On the other hand, since the third heat exchanger 117 is connected downstream of the second pressure reducing valve 116 in the first cycle 105, the third heat exchanger 117 passes through the third heat exchanger 117. The temperature becomes the temperature after the pressure is reduced by the second pressure reducing valve 116 and the temperature is lowered. For this reason, in the second cycle 106, the evaporation temperature of the second medium is higher than the evaporation temperature of the second medium in the third cycle 107. As a result, in the second cycle 106, the blowing temperature of the indoor unit 134 is high, and in the third cycle 107, the blowing temperature of the indoor unit 134 is low. Thus, according to the air conditioning apparatus 100, the 2nd heat exchanger 115 and the 3rd heat exchanger 117 can be connected in series, and cold of two types of temperatures can be supplied.

  In addition, the air-conditioning apparatus 100 is configured to efficiently supply a heat source according to various loads such as warm temperatures of different temperatures or simultaneous heating and cooling.

International Publication No. 2010/131335

  In the air conditioning apparatus 100 described in Patent Document 1, heat loss due to heat exchange between the first medium and the second medium in the second heat exchanger 115 and the third heat exchanger 117 is large. Then, an object of this invention is to provide the air conditioning apparatus with few heat losses and which can be drive | operated according to various load.

This disclosure
An outdoor unit including a first compressor, a first heat exchanger, and a first pressure reduction mechanism;
A plurality of indoor units including an indoor heat exchanger and a flow control valve;
The second compressor, the second heat exchanger, the second pressure reducing mechanism, and the refrigerant discharged from the first compressor are supplied to all of the plurality of indoor units and returned to the first compressor. The refrigerant discharged from the first compressor is supplied to a part of the plurality of indoor units and returned to the first compressor, and the refrigerant discharged from the second compressor is A flow path switching mechanism for switching between a second state supplied to another part of the plurality of indoor units and returned to the second compressor, between the outdoor unit and the plurality of indoor units A refrigerant distribution unit configured to form a refrigerant circuit at
An air conditioner is provided.

  According to the above air conditioner, pressure loss and heat loss are small, and operation according to various loads is possible.

Configuration diagram of an air conditioner according to an embodiment of the present disclosure Block diagram of the air conditioner shown in FIG. Flow chart showing the control performed by the controller The figure which shows the flow of the refrigerant | coolant of the air conditioning apparatus which is air-cooled by uniform load mode The figure which shows the flow of the refrigerant | coolant of the air conditioning apparatus which is air_conditionaing | cooling by nonuniform load mode The flowchart which shows the control performed by a controller when heating operation is carried out The figure which shows the flow of the refrigerant | coolant of the air conditioning apparatus which is heating-operated in uniform load mode The figure which shows the flow of the refrigerant | coolant of the air conditioning apparatus which is heating-operated in nonuniform load mode The flowchart which shows the control performed by a controller when carrying out simultaneous heating and cooling operation The figure which shows the flow of the refrigerant | coolant of the air conditioning apparatus which is carrying out simultaneous heating and cooling The block diagram of the air conditioning apparatus which concerns on a modification Configuration diagram of conventional air conditioner

  In a multi-room type air conditioner in which a plurality of indoor units are connected to one or more outdoor units, the cooling capacity exhibited by each indoor unit depends on the flow rate of the refrigerant circulating through each indoor unit. The flow rate of the refrigerant circulating through each indoor unit is determined by the rotational speed of the compressor. In many cases, the flow rate of the refrigerant circulating through each indoor unit is controlled so that the refrigerant evaporating temperature or the refrigerant liquid temperature in the indoor unit is constant during cooling, and the refrigerant condensing temperature or the refrigerant circuit high pressure during heating. It is controlled to be constant.

  When performing control to keep the evaporating temperature or condensing temperature of the refrigerant constant at the target value, the air conditioning load received by each indoor unit can be uniformly changed by changing the evaporating temperature or condensing temperature target value of the refrigerant. it can. On the other hand, in a multi-room type air conditioner, when the variation in the air conditioning load for each indoor unit is large, the rotation speed of the compressor is often determined so as to match the largest air conditioning load. In this case, in the indoor unit that receives a small air conditioning load, intermittent operation (thermo-on / thermo-off operation) is performed, and the operation efficiency of the air conditioner decreases. Therefore, for example, in order to reduce the cooling capacity exhibited by the indoor unit that receives a small air conditioning load during the cooling operation, it is conceivable to reduce the refrigerant flow rate in the indoor unit by restricting the expansion valve. However, in this case, since the temperature of the refrigerant after passing through the expansion valve becomes low, it may be difficult to reduce the cooling capacity exhibited by the indoor unit that receives a small air conditioning load. Moreover, in order to raise the air_conditioning | cooling capability which the indoor unit which receives large air-conditioning load increases, it is possible to increase the flow rate of a refrigerant | coolant by increasing the opening degree of an expansion valve. However, also in this case, since the temperature of the refrigerant after passing through the expansion valve becomes high, it may be difficult to increase the cooling capacity exhibited by the indoor unit that receives a large air conditioning load. Therefore, it is required to supply liquid refrigerant having an appropriate temperature to the indoor unit.

  In addition, there is an air conditioner capable of simultaneous cooling and heating, in which cooling is performed in a part of the plurality of indoor units and heating is performed in the other part of the plurality of indoor units. When realizing simultaneous cooling and heating operation with the same refrigerant system, use a heat source machine that assumes the use of three pipes, or use two pipes that correspond to specifications different from the cooling / heating switching specifications or simultaneous cooling and heating specifications. In many cases, the assumed heat source machine is used. In addition, when the latent heat sensible heat separation air conditioning is performed for the purpose of keeping the indoor relative humidity within a predetermined range, a device having a desiccant is required separately.

The first aspect of the present disclosure is:
An outdoor unit including a first compressor, a first heat exchanger, and a first pressure reduction mechanism;
A plurality of indoor units including an indoor heat exchanger and a flow control valve;
The second compressor, the second heat exchanger, the second pressure reducing mechanism, and the refrigerant discharged from the first compressor are supplied to all of the plurality of indoor units and returned to the first compressor. The refrigerant discharged from the first compressor is supplied to a part of the plurality of indoor units and returned to the first compressor, and the refrigerant discharged from the second compressor is A flow path switching mechanism for switching between a second state supplied to another part of the plurality of indoor units and returned to the second compressor, between the outdoor unit and the plurality of indoor units A refrigerant distribution unit configured to form a refrigerant circuit at
An air conditioner is provided.

  According to the first aspect, any one of the refrigerant discharged from the first compressor belonging to the outdoor unit and the refrigerant discharged from the second compressor belonging to the refrigerant distribution unit can be selectively supplied to each indoor unit. . For this reason, the air conditioner can be operated according to various loads, and heat loss is small. For example, when the variation in the air conditioning load for each indoor unit is large, the evaporating temperature or the condensing temperature of the refrigerant can be varied so as to match the air conditioning load for each indoor unit. Also, simultaneous cooling and heating operation can be realized.

The second aspect of the present disclosure includes, in addition to the first aspect,
A suction temperature sensor for detecting the temperature of the indoor air sucked into each indoor unit;
The air conditioning load for each indoor unit is calculated based on the difference between the temperature detected by the suction temperature sensor included in each indoor unit and the set temperature of the indoor air in each indoor unit, and the calculated air conditioning for each indoor unit Based on the load, it is determined which of the first state and the second state is to be formed, and when it is determined that the second state is to be formed, each indoor unit is provided with the first compressor and the second state. A controller that determines which of the compressors should be supplied with refrigerant discharged from the compressor, and that controls the flow path switching mechanism so that the second state is formed according to these determinations. A harmony device is provided.

  According to the second aspect, when it is determined that the second state should be formed based on the calculated air-conditioning load for each indoor unit, each indoor unit is started from either the first compressor or the second compressor. It is determined whether the discharged refrigerant should be supplied. Further, according to the determination, the second state is formed. For this reason, the refrigerant | coolant of a desirable state for the air-conditioning load with respect to each indoor unit can be supplied to each indoor unit. Thereby, the operating efficiency of an air conditioning apparatus increases.

  According to a third aspect of the present disclosure, in addition to the second aspect, the controller controls the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor when the cooling operation is performed in the second state. The target value and the target value of the evaporation temperature or the evaporation pressure of the refrigerant discharged from the second compressor are determined so that these target values are different, and based on these determined target values, the first compressor Provided is an air conditioner that controls the rotational speed and the rotational speed of the second compressor. According to the third aspect, during the cooling operation, the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor, and the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the second compressor, Is different. Thereby, the cooling capability exhibited by the indoor unit to which the refrigerant discharged from the first compressor is supplied differs from the cooling capability exhibited by the indoor unit to which the refrigerant discharged from the second compressor is supplied. Can do. Refrigerant in a desired state for the cooling load for each indoor unit can be supplied to each indoor unit.

The fourth aspect of the present disclosure, in addition to the third aspect,
A liquid temperature sensor for detecting the temperature of the refrigerant liquid in the indoor heat exchanger of each indoor unit;
The controller detects the indoor heat exchange belonging to the indoor unit supplied with the refrigerant discharged from the first compressor, which is detected by the liquid temperature sensor when the cooling operation is performed in the second state. The number of revolutions of the first compressor is controlled so that the representative value of the temperature of the refrigerant liquid in the compressor approaches the target value of the evaporation temperature of the refrigerant discharged from the first compressor, and the liquid temperature sensor The representative value of the temperature of the refrigerant liquid in the indoor heat exchanger belonging to the indoor unit to which the refrigerant discharged from the second compressor is supplied is detected by the refrigerant discharged from the second compressor. Provided is an air conditioner that controls the rotational speed of the second compressor so as to approach the target value of the evaporation temperature.

  According to the fourth aspect, the representative value of the temperature of the refrigerant liquid in the indoor heat exchanger of each indoor unit detected by the liquid temperature sensor is the evaporation temperature of the refrigerant discharged from the first compressor or the second compressor. The rotation speed of the first compressor or the rotation speed of the second compressor can be controlled so as to approach the target value.

The fifth aspect of the present disclosure includes, in addition to the third aspect,
A first suction pressure sensor for detecting the suction pressure of the refrigerant into the first compressor;
A second suction pressure sensor for detecting the suction pressure of the refrigerant into the second compressor,
The controller is configured such that when the cooling operation is performed in the second state, the saturation temperature of the refrigerant calculated based on the pressure detected by the first suction pressure sensor is discharged from the first compressor. The rotation speed of the first compressor is controlled so as to approach the target value of the evaporation temperature of the refrigerant, and the saturation temperature of the refrigerant calculated based on the pressure detected by the second suction pressure sensor is Provided is an air conditioner that controls the rotational speed of the second compressor so as to approach the target value of the evaporation temperature of refrigerant discharged from the compressor.

  According to the fifth aspect, the first compression is performed so that the saturation temperature of the refrigerant calculated based on the suction pressure of the refrigerant to the first compressor approaches the target value of the evaporation temperature of the refrigerant discharged from the first compressor. The number of revolutions of the machine can be controlled. Further, the rotation speed of the second compressor is set so that the saturation temperature of the refrigerant calculated based on the suction pressure of the refrigerant to the second compressor approaches the target value of the evaporation temperature of the refrigerant discharged from the second compressor. Can be controlled.

  In a sixth aspect of the present disclosure, in addition to the second aspect, the controller is configured to control a condensation temperature or a condensation pressure of the refrigerant discharged from the first compressor when the heating operation is performed in the second state. The target value and the target value of the condensing temperature or condensing pressure of the refrigerant discharged from the second compressor are determined so that these target values are different, and based on the determined target values, the first compressor Provided is an air conditioner that controls the rotational speed and the rotational speed of the second compressor. According to the sixth aspect, during the heating operation, the target value of the condensation temperature or condensation pressure of the refrigerant discharged from the first compressor, and the target value of the condensation temperature or condensation pressure of the refrigerant discharged from the second compressor Can be different. Thereby, the heating capability exhibited by the indoor unit to which the refrigerant discharged from the first compressor is supplied differs from the heating capability exhibited by the indoor unit to which the refrigerant discharged from the second compressor is supplied. Can do. Refrigerant in a state desirable for the heating load for each indoor unit can be supplied to each indoor unit.

The seventh aspect of the present disclosure includes, in addition to the sixth aspect,
A first discharge pressure sensor for detecting the discharge pressure of the refrigerant from the first compressor;
A second discharge pressure sensor for detecting the discharge pressure of the refrigerant from the second compressor,
The controller is configured such that when the heating operation is performed in the second state, the refrigerant saturation temperature calculated based on the pressure detected by the first discharge pressure sensor is discharged from the first compressor. The rotation speed of the first compressor is controlled so as to approach the target value of the condensing temperature of the refrigerant, and the saturation temperature of the refrigerant calculated based on the pressure detected by the second discharge pressure sensor is the second An air conditioner is provided that controls the rotational speed of the second compressor so as to approach the target value of the condensation temperature of refrigerant discharged from the compressor.

  According to the seventh aspect, the first compression is performed so that the saturation temperature of the refrigerant calculated based on the discharge pressure of the refrigerant from the first compressor approaches the target value of the condensation temperature of the refrigerant discharged from the first compressor. The number of revolutions of the machine can be controlled. Further, the rotation speed of the second compressor is set so that the saturation temperature of the refrigerant calculated based on the discharge pressure of the refrigerant from the second compressor approaches the target value of the condensation temperature of the refrigerant discharged from the second compressor. Can be controlled.

  In an eighth aspect of the present disclosure, in addition to the first aspect, a cooling operation is performed in a part of the plurality of indoor units, and a cooling operation is performed in another part of the plurality of indoor units. When the capacity of the indoor unit in which the operation is performed is larger than the capacity of the indoor unit in which the heating operation is performed, the refrigerant discharged from the first compressor is supplied to the indoor unit in which the cooling operation is performed, And a controller for controlling the flow path switching mechanism so as to form the second state in which the refrigerant discharged from the second compressor is supplied to the indoor unit in which the heating operation is performed. An air conditioner is provided. According to the eighth aspect, in the simultaneous cooling and heating operation, when the capacity of the indoor unit in which the cooling operation is performed is larger than the capacity of the indoor unit in which the heating operation is performed, the refrigerant discharged from the first compressor is cooled. Can be supplied to indoor units.

  In a ninth aspect of the present disclosure, in addition to the eighth aspect, the controller may perform the cooling operation when the capacity of the indoor unit in which the cooling operation is performed is smaller than the capacity of the indoor unit in which the heating operation is performed. The refrigerant discharged from the second compressor is supplied to the indoor unit in which the refrigerant is discharged, and the refrigerant discharged from the first compressor is supplied to the indoor unit in which the heating operation is performed. An air conditioner that controls the flow path switching mechanism so as to form a state is provided. According to the ninth aspect, in the simultaneous cooling and heating operation, when the capacity of the indoor unit in which the cooling operation is performed is smaller than the capacity of the indoor unit in which the heating operation is performed, the refrigerant discharged from the first compressor is heated in the heating operation. Can be supplied to indoor units.

  According to a tenth aspect of the present disclosure, in addition to any one of the first to ninth aspects, in the second heat exchanger, the second heat exchanger in the flow direction of the fluid that exchanges heat with the refrigerant. Provided is an air conditioner further comprising a humidity regulator disposed downstream and having a desiccant to absorb or release moisture. According to the tenth aspect, moisture can be absorbed or released in the desiccant using the fluid that has dissipated or absorbed heat by heat exchange with the refrigerant in the second heat exchanger. Thereby, the humidity of room air can be adjusted.

  An eleventh aspect of the present disclosure provides an air conditioner, in addition to any one of the first to tenth aspects, wherein the refrigerant is a refrigerant having a global warming potential of 2090 or less. According to the eleventh aspect, the environmental load can be reduced.

  A twelfth aspect of the present disclosure provides an air conditioner in which the refrigerant is a natural refrigerant in addition to any one of the first to tenth aspects. According to the twelfth aspect, the environmental load can be reduced.

  According to a thirteenth aspect of the present disclosure, in addition to any one of the first to tenth aspects, an air conditioner is provided in which the refrigerant is a refrigerant mainly composed of fluorocarbon.

A fourteenth aspect of the present disclosure includes
A refrigerant distribution unit to be incorporated in an air conditioner having an outdoor unit including a first compressor, a first heat exchanger, and a first pressure reducing mechanism, and a plurality of indoor units including an indoor heat exchanger and an indoor expansion valve. There,
A second compressor,
A second heat exchanger;
A second decompression mechanism;
A first state in which the refrigerant discharged from the first compressor is supplied to all of the plurality of indoor units and returned to the first compressor when incorporated in the air conditioner; and the first compression The refrigerant discharged from the unit is supplied to a part of the plurality of indoor units and returned to the first compressor, and the refrigerant discharged from the second compressor is another one of the plurality of indoor units. A flow path switching mechanism for switching between a second state supplied to the unit and returned to the second compressor,
Provided is a refrigerant distribution unit configured to form a refrigerant circuit between the outdoor unit and the plurality of indoor units when incorporated in the air conditioner.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description relates to an example of the present invention, and the present invention is not limited to these.

<Configuration of air conditioner>
As shown in FIG. 1, the air conditioner 1a includes an outdoor unit 2, a refrigerant distribution unit 3a, a refrigerant distribution unit 3b, an indoor unit 4a, an indoor unit 4b, an indoor unit 4c, and an indoor unit 4d. The outdoor unit 2 includes a first compressor 21, a first heat exchanger 22, and a first pressure reduction mechanism 24. The first compressor 21 is a variable capacity compressor. The first compressor 21 is controlled by, for example, an inverter (not shown), and the number of rotations of the first compressor 21 can be adjusted according to a change in the air conditioning load. The first pressure reducing mechanism 24 is, for example, an electric expansion valve. The outdoor unit 2 further includes an outdoor blower 23, a four-way valve 25, and an accumulator 26. Outdoor air is supplied to the first heat exchanger 22 by the outdoor blower 23. By the four-way valve 25, the cooling operation and the heating operation of the air conditioner 1a are switched. In the cooling operation, the four-way valve 25 forms a refrigerant flow path as shown by a solid line in FIG. In the heating operation, the four-way valve 25 forms a refrigerant flow path as shown by a broken line in FIG. In the outdoor unit 2, during the cooling operation, the refrigerant discharged from the first compressor 21 is supplied to the outside of the outdoor unit 2 via the four-way valve 25, the first heat exchanger 22, and the first pressure reducing mechanism 24. It is comprised so that. Further, the outdoor unit 2 is configured such that the refrigerant returned to the outdoor unit 2 is sucked into the first compressor 21 via the four-way valve 25 and the accumulator 26 during the cooling operation. The outdoor unit 2 is configured such that the refrigerant discharged from the first compressor 21 is supplied to the outside of the outdoor unit 2 without passing through the first heat exchanger 22 and the second pressure reducing mechanism 24 during the heating operation. Yes. In the outdoor unit 2, during the heating operation, the refrigerant returned to the outdoor unit 2 is transferred to the first compressor 21 via the first pressure reduction mechanism 24, the first heat exchanger 22, the four-way valve 25, and the accumulator 26. It is configured to be inhaled.

  The indoor unit 4a, the indoor unit 4b, the indoor unit 4c, and the indoor unit 4d include an indoor heat exchanger 41 and a flow rate adjustment valve 42, respectively. The flow rate adjustment valve 42 is an expansion valve having a variable opening, for example, an electric expansion valve. Each of the indoor units 4 a to 4 d includes an indoor fan 43. The room air sucked by the room blower 43 exchanges heat with the refrigerant flowing through the room heat exchanger 41 and is returned to the room. Thereby, indoor cooling or heating is performed.

  The refrigerant distribution unit 3a and the refrigerant distribution unit 3b are units to be incorporated in the air conditioning apparatus 1a, respectively. The refrigerant distribution unit 3a and the refrigerant distribution unit 3b include a second compressor 31, a second heat exchanger 32, a second pressure reduction mechanism 34, and a flow path switching mechanism 30, respectively. The refrigerant distribution unit 3a and the refrigerant distribution unit 3b further include a blower 33, a four-way valve 35, and an accumulator 36, respectively. The refrigerant distribution unit 3a is configured to form a refrigerant circuit between the outdoor unit 2, the indoor unit 4a, and the indoor unit 4b. The refrigerant distribution unit 3b is configured to form a refrigerant circuit between the outdoor unit 2, the indoor unit 4c, and the indoor unit 4d. The refrigerant distribution unit 3a and the refrigerant distribution unit 3b perform the cooling operation or the heating operation by supplying the refrigerant discharged from the second compressor 31 to the indoor units 4a to 4d as necessary. In the refrigerant distribution unit 3a and the refrigerant distribution unit 3b, during the cooling operation, the refrigerant discharged from the second compressor 31 is distributed through the four-way valve 35, the second heat exchanger 32, and the second pressure reducing mechanism 34. It is configured to be supplied to the outside of the unit 3a or the refrigerant distribution unit 3b. Further, the refrigerant distribution unit 3a and the refrigerant distribution unit 3b allow the refrigerant returned to the refrigerant distribution unit 3a or the refrigerant distribution unit 3b to be sucked into the first compressor 31 via the four-way valve 35 and the accumulator 36 during the cooling operation. It is configured to be. The refrigerant distribution unit 3a and the refrigerant distribution unit 3b are configured so that the refrigerant discharged from the second compressor 31 during the heating operation does not pass through the second heat exchanger 32 and the second pressure reducing mechanism 34, or the refrigerant distribution unit 3a or the refrigerant distribution unit. It is configured to be supplied to the outside of the unit 3b. Further, the refrigerant distribution unit 3a and the refrigerant distribution unit 3b are configured so that the refrigerant returned to the refrigerant distribution unit 3a or the refrigerant distribution unit 3b during the heating operation is converted into the second decompression mechanism 34, the second heat exchanger 32, the four-way valve 35, And it is comprised so that it may be suck | inhaled by the 2nd compressor 31 via the accumulator 36. FIG.

  The second compressor 31 is a variable capacity compressor. The second compressor 31 is controlled by, for example, an inverter (not shown), and the number of rotations of the second compressor 31 can be adjusted according to a change in the air conditioning load.

  The flow path switching mechanism 30 is a mechanism for switching between the first state and the second state. The first state is a state in which the refrigerant discharged from the first compressor 21 is supplied to all of the plurality of indoor units 4 a to 4 d and returned to the first compressor 21. In the second state, the refrigerant discharged from the first compressor 21 is supplied to a part of the plurality of indoor units 4a to 4d, returned to the first compressor 21, and discharged from the second compressor 31. The refrigerant is supplied to the other part of the plurality of indoor units 4 a to 4 d and returned to the second compressor 31. The plurality of indoor units 4a to 4d do not include indoor units that have been suspended. Specifically, the flow path switching mechanism 30 belonging to the refrigerant distribution unit 3a includes the first state in which the refrigerant discharged from the first compression mechanism 21 is supplied to the indoor unit 4a and the indoor unit 4b, and the first compression mechanism 21. Switching between the second state in which the discharged refrigerant is supplied to one of the indoor unit 4a and the indoor unit 4b, and the refrigerant discharged from the second compression mechanism 31 is supplied to the other of the indoor unit 4a and the indoor unit 4b. . Further, the flow path switching mechanism 30 belonging to the refrigerant distribution unit 3b is discharged from the first compression mechanism 21 in a first state in which the refrigerant discharged from the first compression mechanism 21 is supplied to the indoor unit 4c and the indoor unit 4d. The refrigerant is supplied to one of the indoor unit 4c and the indoor unit 4d, and the refrigerant discharged from the second compression mechanism 31 is switched to the second state where the refrigerant is supplied to the other of the indoor unit 4c and the indoor unit 4d.

  The blower 33 is configured to create an air flow such that air sucked from the outside passes through the second heat exchanger 32 and is discharged to the outside. The blower 33 may be configured to create an air flow in which air sucked from a predetermined room passes through the second heat exchanger 32 and is discharged to the outside.

  As shown in FIG. 1, the refrigerant distribution unit 3a and the refrigerant distribution unit 3b are connected to the outdoor unit 2 by a common liquid channel 11 and a common gas channel 12, respectively. The refrigerant distribution unit 3a and the refrigerant distribution unit 3b have a first relay channel 13a and a second relay channel 13b, respectively. The first relay channel 13 a is connected to the common liquid channel 11. Further, the second relay flow path 13 b is connected to the common gas flow path 12. The refrigerant distribution unit 3a is connected to the indoor unit 4a by the first connection liquid channel 14a and the first connection gas channel 15a. The refrigerant distribution unit 3a is connected to the indoor unit 4b by the second connection liquid channel 14b and the second connection gas channel 15b. The refrigerant distribution unit 3b is connected to the indoor unit 4c by the third connection liquid channel 14c and the third connection gas channel 15c. The refrigerant distribution unit 3b is connected to the indoor unit 4d by a fourth connection liquid channel 14d and a fourth connection gas channel 15d. The first relay channel 13 a has two branch portions on the opposite side of the common liquid channel 11. One of the two branch parts is connected to the first connection liquid channel 14a or the third connection liquid channel 14c, and the other of the two branch parts is the second connection liquid channel 14b or the fourth connection liquid channel. 14d. The second relay channel 13 b has two branch portions on the opposite side of the common gas channel 12. One of the two branch portions is connected to the first connection gas flow path 15a or the third connection gas flow path 15c, and the other of the two branch portions is the second connection gas flow path 15b or the fourth connection gas flow path. 15d. The flow path extending from the second decompression mechanism 34 to the opposite side of the second heat exchanger 32 branches in the middle and is connected to the first connection liquid flow path 14a and the second connection liquid flow path 14b, or the third The connection liquid channel 14c and the fourth connection liquid channel 14d are connected. The flow path extending from the four-way valve 35 to the opposite side of the accumulator 36 is branched halfway and connected to the first connection gas flow path 15a and the second connection gas flow path 15b, or the third connection gas flow path. 15c and the fourth connection gas flow path 15d.

  The flow path switching mechanism 30 includes a first low pressure switching valve 37a, a second low pressure switching valve 37b, a third low pressure switching valve 37c, a fourth low pressure switching valve 37d, a first high pressure switching valve 38a, a second high pressure switching valve 38b, A third high pressure switching valve 38c and a fourth high pressure switching valve 38d are provided. These valves are, for example, electromagnetic valves. The first low-pressure switching valve 37a is provided at a branch portion of the first relay flow path 13a that is connected to the first connection liquid flow path 14a or the third connection liquid flow path 14c. The second low pressure switching valve 37b is provided at a branch portion of the first relay flow path 13a that is connected to the second connection liquid flow path 14b or the fourth connection liquid flow path 14d. The third low-pressure switching valve 37c is a branch connected to the first connection liquid flow path 14a or the third connection liquid flow path 14c in the flow path extending from the second pressure reduction mechanism 34 to the opposite side of the second heat exchanger 32. It is provided in the part. The fourth low-pressure switching valve 37d is a branch that is connected to the second connection liquid flow path 14b or the fourth connection liquid flow path 14d in the flow path that extends from the second pressure reduction mechanism 34 to the opposite side of the second heat exchanger 32. It is provided in the part. The first high-pressure switching valve 38a is provided at a branch portion of the second relay flow path 13b that is connected to the first connection gas flow path 15a or the third connection gas flow path 15c. The second high-pressure switching valve 38b is provided at a branch portion of the second relay channel 13b that is connected to the second connection gas channel 15b or the fourth connection gas channel 15d. The third high-pressure switching valve 38c is provided at a branch portion of the flow path extending from the four-way valve 35 to the opposite side of the accumulator 36 and connected to the first connection gas flow path 15a or the third connection gas flow path 15c. ing. The fourth high-pressure switching valve 38d is provided at a branch portion of the flow path extending from the four-way valve 35 to the opposite side of the accumulator 36 and connected to the second connection gas flow path 15b or the fourth connection gas flow path 15d. ing.

  Although the refrigerant | coolant which circulates through the air conditioning apparatus 1a is not restrict | limited in particular, For example, a refrigerant | coolant is a refrigerant | coolant which has a global warming coefficient of 2090 or less. Examples of such a refrigerant include R410A. The refrigerant may be a natural refrigerant. Examples of the natural refrigerant include hydrocarbons such as ammonia, propane, and butane, carbon dioxide, and water. In this case, the environmental load can be reduced. The refrigerant may be a refrigerant mainly composed of fluorocarbon.

  The air conditioner 1a may include a plurality of outdoor units 2. The air conditioning apparatus 1a may include one refrigerant distribution unit or three or more refrigerant distribution units. The air conditioner 1a may be configured such that two or more indoor units are connected to each refrigerant distribution unit 3a, 3b.

  As shown in FIG. 2, the air conditioning apparatus 1 a includes a controller 50. The controller 50 includes a controller 50a, a controller 50b, a controller 50c, a controller 50d, a controller 50e, a controller 50f, and a controller 50g. The control unit 50a to the control unit 50g each include a memory that stores a control program or various data, a memory that can temporarily store and rewrite various data, and a calculation device such as a CPU that performs various calculations. Contains. The control unit 50a to the control unit 50g are connected so as to be communicable with each other, for example, by a transmission line.

  The control unit 50 a is provided in the outdoor unit 2 and controls the first compressor 21, the first pressure reducing mechanism 24, the outdoor blower 23, and the four-way valve 25. The outdoor unit 2 includes a compressor temperature sensor 27, an outside air temperature sensor 28, a first discharge pressure sensor 29a, and a first suction pressure sensor 29b. The compressor temperature sensor 29 is a sensor for detecting the temperature of the refrigerant discharged from the first compressor 21. The outside air temperature sensor 28 is a sensor for detecting the temperature of outdoor air. The first discharge pressure sensor 29 a is a sensor for detecting the discharge pressure of the refrigerant from the first compressor 21. In other words, the first discharge pressure sensor 29a is a sensor for detecting the pressure of the refrigerant discharged from the first compressor 21. The first suction pressure sensor 29 b is a sensor for detecting the suction pressure of the refrigerant to the first compressor 21. That is, the first suction pressure sensor 29b is a sensor for detecting the pressure of the refrigerant sucked into the first compressor 21. The controller 50a is connected to these sensors so as to obtain detection signals indicating detection results in the compressor temperature sensor 27, the outside air temperature sensor 28, the first discharge pressure sensor 29a, and the first suction pressure sensor 29b. Has been. Moreover, the control part 50a is connected to these components so that the 1st compressor 21, the 1st pressure reduction mechanism 24, the outdoor air blower 23, and the four-way valve 25 can acquire a control signal from the control part 50a.

  The control unit 50a is configured based on the detection signal acquired from the sensor or the signals acquired from the control units 50b to 50g according to the refrigerant pressure or the refrigerant temperature target value determined by the stored control program. To control.

  The controller 50b is provided in the refrigerant distribution unit 3a. The control unit 50b controls the second compressor 31, the second pressure reducing mechanism 34, the blower 33, the four-way valve 35, and the flow path switching mechanism 30 that belong to the refrigerant distribution unit 3a. The controller 50c is provided in the refrigerant distribution unit 3b. The control unit 50c controls the second compressor 31, the second pressure reducing mechanism 34, the blower 33, the four-way valve 35, and the flow path switching mechanism 30 that belong to the refrigerant distribution unit 3b. The refrigerant distribution unit 3a and the refrigerant distribution unit 3b include a compressor temperature sensor 39a, a second discharge pressure sensor 39b, and a second suction pressure sensor 39c, respectively. The compressor temperature sensor 39 a is a sensor for detecting the temperature of the refrigerant discharged from the second compressor 31. The second discharge pressure sensor 39 b is a sensor for detecting the discharge pressure of the refrigerant from the second compressor 31. That is, the second discharge pressure sensor 39b is a sensor for detecting the pressure of the refrigerant discharged from the second compressor 31. The second suction pressure sensor 39 c is a sensor for detecting the suction pressure of the refrigerant to the second compressor 31. That is, the second suction pressure sensor 39c is a sensor for detecting the pressure of the refrigerant sucked into the second compressor 31.

  The control unit 50b and the control unit 50c are connected to these sensors so as to acquire signals indicating detection results in the compressor temperature sensor 39a, the second discharge pressure sensor 39b, and the second suction pressure sensor 39c, respectively. ing. In addition, the second compressor 31, the second pressure reducing mechanism 34, the blower 33, the four-way valve 35, and the flow path switching mechanism 30 may be configured so that the control unit 50b or the control unit 50c can acquire a control signal. It is connected to the control unit 50c.

  The control unit 50b and the control unit 50c are based on the detection signal acquired from the sensor or the signals acquired from the control units 50b to 50g, according to the target value of the refrigerant pressure or the refrigerant temperature determined by the stored control program. Each component of the distribution unit 3a or the refrigerant distribution unit 3b is controlled.

  The control unit 50d, the control unit 50e, the control unit 50f, and the control unit 50g are provided in the indoor unit 4a, the indoor unit 4b, the indoor unit 4c, and the indoor unit 4d, respectively, and the flow rate adjusting valve 42 and the indoor blower that belong to these units. 43 is controlled. The indoor unit 4a, the indoor unit 4b, the indoor unit 4c, and the indoor unit 4d include a gas temperature sensor 45a, a liquid temperature sensor 45b, a suction temperature sensor 47a, and an outlet temperature sensor 47b, respectively. The gas temperature sensor 45 a is a sensor for detecting the temperature of the gas refrigerant in the indoor heat exchanger 41. The liquid temperature sensor 45b is a sensor for detecting the temperature of the liquid refrigerant in the indoor heat exchanger 41. The suction temperature sensor 47a is a sensor for detecting the temperature of the indoor air sucked into the indoor units 4a to 4d. The blowing temperature sensor 47b is a sensor for detecting the temperature of indoor air blown into the room from each of the indoor units 4a to 4d.

  The control parts 50d-50g can acquire the detection signal which means the detection result in the gas temperature sensor 45a, the liquid temperature sensor 45b, the suction temperature sensor 47a, and the blowing temperature sensor 47b which belongs to each indoor unit 4a-4d, Connected to these sensors. Moreover, the control parts 50d-50g are connected to the flow control valve 42 and the indoor air blower 43 so that the flow control valve 42 and the indoor air blower 43 can acquire a control signal from the control parts 50d-50g. In addition, a signal for starting or stopping the operation of each of the indoor units 4a to 4d or a signal regarding a set value such as a set room temperature and a set air volume is input from the remote controller 49 to the control units 50d to 50g. The control units 50d to 50g store a set temperature Tset of room temperature air in the indoor units 4a to 4d.

  The control units 50d to 50g are appropriately determined by a stored control program based on a signal such as a signal input from the remote controller 49, a detection signal acquired from each of the sensors, or a signal acquired from another control unit. The opening degree of the flow rate adjustment valve 42 or the rotation speed of the indoor blower 43 is controlled according to a target value indicating the state of the refrigerant.

  When the air conditioning apparatus 1a includes a plurality of outdoor units 2, one control unit 50a among the plurality of control units 50a is set as a master unit, and the other control unit 50a is set as a slave unit. The control unit 50a set as the slave unit controls each component of the outdoor unit 2 to which the control unit 50a set as the slave unit belongs in accordance with a command from the control unit 50a set as the master unit.

<Operation of air conditioner>
Next, the operation of the air conditioner 1a will be described. In the air conditioner 1a, a cooling operation, a heating operation, or a simultaneous cooling and heating operation is performed according to the demands of the indoor units 4a to 4d. The cooling operation of the air conditioner 1a includes a uniform load mode and a non-uniform load mode. The cooling operation in the uniform load mode is performed when the variation in the cooling load for each of the indoor units 4a to 4d is small. The cooling operation in the non-uniform load mode is performed when the variation in the cooling load for each of the indoor units 4a to 4d is large. The heating operation of the air conditioner 1a includes a uniform load mode and a non-uniform load mode. The heating operation in the uniform load mode is performed when the variation in the heating load for each of the indoor units 4a to 4d is small. The heating operation in the non-uniform load mode is performed when the variation in the heating load for each of the indoor units 4a to 4d is large. These operations are performed in the air conditioner 1a by the action of the controller 50. The controller 50 is independent of the following for the group including the refrigerant distribution unit 3a, the indoor unit 4a, and the indoor unit 4b, and the group including the refrigerant distribution unit 3b, the indoor unit 4c, and the indoor unit 4d. Control.

(Cooling operation in uniform load mode)
As illustrated in FIG. 3, the controller 50 determines whether or not the requests from all the indoor units 4a to 4d are cooling in step S101. Here, all indoor units do not include indoor units that are not in operation. If the determination in step S101 is affirmative (Yes), the controller 50 executes the processes of steps S102 and S103. That is, the controller 50 acquires the temperature Tac detected by the suction temperature sensor 47a included in each of the indoor units 4a to 4d. Then, the air conditioning load (cooling load) for each of the indoor units 4a to 4d is calculated based on the difference between the temperature Tac and the set temperature Tset of the indoor air in each of the indoor units 4a to 4d. Specifically, the controller 50 determines the air conditioning load (cooling load) for each indoor unit 4a to 4d based on the change over time of the difference between the temperature Tac in each indoor unit 4a to 4d and the set temperature Tset in each indoor unit 4a to 4d. ) Is calculated. The controller 50 determines which of the first state and the second state should be formed based on the calculated air conditioning load (cooling load) for each of the indoor units 4a to 4d. Specifically, in step S104, the controller 50 determines whether or not the difference in air conditioning load (cooling load) for each of the indoor units 4a to 4d is greater than or equal to a predetermined value. For example, the controller 50 determines whether or not the difference between the air conditioning load (cooling load) for the indoor unit 4a and the air conditioning load (cooling load) for the indoor unit 4b is greater than or equal to a predetermined value, or air conditioning for the indoor unit 4c. It is determined whether or not the difference between the load (cooling load) and the air conditioning load (cooling load) for the indoor unit 4d is equal to or greater than a predetermined value.

  If the determination in step S104 is negative (No), the controller 50 determines that the first state should be formed. In this case, the controller 50 sets the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor 21 based on the air conditioning load (cooling load) for each of the indoor units 4a to 4d in step S121. decide. In addition, in step S122, the controller 50 controls the flow path switching mechanism 30 so that the first state is formed. Specifically, the controller 50 has the first low pressure switching valve 37a opened, the second low pressure switching valve 37b opened, the third low pressure switching valve 37c closed, the fourth low pressure switching valve 37d closed, The flow path switching mechanism 30 is controlled so that the one high pressure switching valve 38a is opened, the second high pressure switching valve 38b is opened, the third high pressure switching valve 38c is closed, and the fourth high pressure switching valve 38d is closed. At this time, the controller 50 controls the four-way valve 25 so that the four-way valve 25 forms a flow path indicated by a solid line in FIG. In addition, in step S123, the controller 50 determines the rotation speed of the first compressor 21 based on the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor 21 determined in step S121. To control. Thereby, the air-conditioning apparatus 1a performs the cooling operation in the first state. In other words, the cooling operation in the uniform load mode is performed.

  When the cooling operation in the uniform load mode is performed, the refrigerant flows in the air conditioner 1a as shown in FIG. The thick line in FIG. 4 shows the flow path through which the refrigerant flows, and the arrow in FIG. 4 shows the direction in which the refrigerant flows. The gas refrigerant discharged from the first compressor 21 passes through the four-way valve 25 and is condensed by exchanging heat with outdoor air in the first heat exchanger 22. The condensed liquid refrigerant is decompressed by the first decompression mechanism 24, passes through the common liquid flow path 11, and flows into the first relay flow path 13a of the refrigerant distribution unit 3a or the refrigerant distribution unit 3b. The refrigerant that has flowed into the first relay flow path 13a of the refrigerant distribution unit 3a is supplied to the indoor unit 4a via the first low pressure switching valve 37a and the first connection liquid flow path 14a, or the second low pressure switching valve 37b. And it is supplied to the indoor unit 4b via the second connection liquid channel 14b. The refrigerant flowing into the first relay flow path 13a of the refrigerant distribution unit 3b is supplied to the indoor unit 4c via the first low pressure switching valve 37a and the third connection liquid flow path 14c, or the second low pressure switching valve 37b. And it is supplied to the indoor unit 4d via the fourth connection liquid channel 14d. The refrigerant supplied to each of the indoor units 4a to 4d is decompressed by passing through the flow rate adjusting valve 42, and evaporates by exchanging heat with the indoor air sucked by the indoor blower 43 in the indoor heat exchanger 41. As a result, the room air is cooled, and the cooled room air is returned to the room for cooling. The refrigerant flowing out of each of the indoor units 4a to 4d returns to the outdoor unit 2 via the first high pressure switching valve 38a or the second high pressure switching valve 38b, the second relay flow path 13b, and the common gas flow path 12. The refrigerant returned to the outdoor unit 2 passes through the four-way valve 25 and flows into the accumulator 26. The refrigerant adjusted to an appropriate dryness in the accumulator 26 is sucked into the first compressor 21. At this time, the operation of the second compressor 31 is stopped.

  The controller 50 changes the target value of the evaporating temperature or evaporating pressure of the refrigerant discharged from the first compressor 21 according to the change of the air conditioning load (cooling load) for each of the indoor units 4a to 4d, and changes the The rotational speed of the first compressor 21 is controlled according to the target value. For example, when the air conditioning load (cooling load) for each of the indoor units 4a to 4d decreases, the rotation speed of the first compressor 21 is decreased. Moreover, the rotation speed of the outdoor air blower 23 may be lowered so that the air flow rate of the outdoor air blower 23 is lowered, and the amount of heat exchanged in the first heat exchanger 22 may be reduced. Moreover, when the air conditioning apparatus 1a includes a plurality of outdoor units 2, when the air conditioning load on each of the indoor units 4a to 4d becomes extremely small with respect to the capacity of the outdoor unit 2, a part of the outdoor unit 2 is operated. May be stopped. However, when the variation of the air conditioning load for each of the indoor units 4a to 4d is large, the controller 50 shifts from the cooling operation in the uniform load mode to the cooling operation in the non-uniform load mode.

(Cooling operation in non-uniform load mode)
If the determination in step S104 is affirmative (Yes), the controller 50 determines that the second state should be formed. In this case, it is determined whether the refrigerant discharged from the first compressor 21 or the second compressor 31 should be supplied to each of the indoor units 4a to 4d, and the second state is formed according to these determinations. Thus, the flow path switching mechanism 30 is controlled. At this time, the controller 50 controls the four-way valve 25 and the four-way valve 35 so that the four-way valve 25 and the four-way valve 35 form a flow path indicated by a solid line in FIG. Thereby, in the air conditioner 1a, the cooling operation is performed in the second state. In other words, the cooling operation in the non-uniform load mode is performed.

  Further, the controller 50 is configured so that when the cooling operation is performed in the second state, the target value of the evaporation temperature or the evaporation pressure of the refrigerant discharged from the first compressor 21 and the refrigerant discharged from the second compressor 31. The target value of the evaporation temperature or the evaporation pressure is determined so that these target values are different. Then, the controller 50 controls the rotational speed of the first compressor 21 and the rotational speed of the second compressor 31 based on these determined target values.

  The controller 50 is, for example, an indoor heat exchanger belonging to the indoor unit to which the refrigerant discharged from the first compressor 21 is detected, which is detected by the liquid temperature sensor 45b when the cooling operation is performed in the second state. The rotational speed of the first compressor 21 is controlled such that the representative value Ts1 of the refrigerant liquid temperature at 43 approaches the target value of the evaporation temperature of the refrigerant discharged from the first compressor 21. Further, the controller 50 detects a representative value Ts2 of the temperature of the refrigerant liquid in the indoor heat exchanger 43 belonging to the indoor unit to which the refrigerant discharged from the second compressor 31 is supplied, which is detected by the liquid temperature sensor 45b. The rotation speed of the second compressor 31 is controlled so as to approach the target value of the evaporation temperature of the refrigerant discharged from the second compressor 31. Here, when the number of indoor units to which the refrigerant discharged from the first compressor 21 is supplied is the representative value Ts1 of the temperature of the refrigerant liquid, in the indoor heat exchanger 43 belonging to the indoor unit. It means the temperature of the refrigerant liquid. Further, the representative value Ts1 of the temperature of the refrigerant liquid is, in the indoor heat exchanger 43 belonging to those indoor units, when there are a plurality of indoor units to which the refrigerant discharged from the first compressor 21 is supplied. It means the average value, maximum value, or minimum value of the temperature of the refrigerant liquid. When the number of indoor units supplied with the refrigerant discharged from the second compressor 31 is one, the representative value Ts2 of the temperature of the refrigerant liquid is the refrigerant liquid in the indoor heat exchanger 43 belonging to the indoor unit. It means temperature. When there are a plurality of indoor units to which the refrigerant discharged from the second compressor 31 is supplied, the representative value Ts2 of the temperature of the refrigerant liquid is the refrigerant liquid in the indoor heat exchanger 43 belonging to those indoor units. Mean value, maximum value, or minimum value of the temperature.

  For example, when the cooling operation is performed in the second state, the controller 50 discharges from the first compressor 21 the saturation temperature of the refrigerant calculated based on the pressure detected by the first suction pressure sensor 29b. The rotation speed of the first compressor 21 is controlled so as to approach the target value of the evaporation temperature of the refrigerant. In addition, the controller 50 sets the refrigerant saturation temperature calculated based on the pressure detected by the second suction pressure sensor 39c so as to approach the target value of the evaporation temperature of the refrigerant discharged from the second compressor 31. The rotational speed of the two compressors 31 is controlled. The refrigerant saturation temperature calculated based on the pressure detected by the first suction pressure sensor 29b is, for example, the refrigerant saturation temperature at the pressure detected by the first suction pressure sensor 29b. In addition to the pressure detected by the first suction pressure sensor 29b, the saturation temperature of the refrigerant is calculated in consideration of the pressure loss of the refrigerant flow estimated from the estimated pipe length and the refrigerant flow rate. May be. The refrigerant saturation temperature calculated based on the pressure detected by the second suction pressure sensor 39c is, for example, the refrigerant saturation temperature at the pressure detected by the second suction pressure sensor 39c. In addition to the pressure detected by the second suction pressure sensor 39c, the saturation temperature of the refrigerant is calculated in consideration of the pressure loss of the refrigerant flow estimated from the estimated pipe length and the refrigerant flow rate. May be.

  As shown in FIG. 3, the controller 50 determines in step S <b> 105 whether the refrigerant discharged from the first compressor 21 or the second compressor 31 should be supplied to each of the indoor units 4 a to 4 d. The controller 50 is, for example, one of the indoor unit 4a and the indoor unit 4b that has a larger capacity than the first compressor 21 and the second compressor 31 in the indoor unit that receives a larger air conditioning load (cooling load). It is determined that the discharged refrigerant should be supplied. Further, the controller 50 has a smaller capacity of the first compressor 21 and the second compressor 31 in the indoor unit 4a and the indoor unit 4b that receives a smaller air conditioning load (cooling load). It is determined that the discharged refrigerant should be supplied. Here, it is assumed that the air conditioning load (cooling load) for the indoor unit 4a is larger than the air conditioning load (cooling load) for the indoor unit 4b by a predetermined value or more. Further, it is assumed that the capacity of the first compressor 21 is larger than the capacity of the second compressor 31. The controller 50 determines that the refrigerant discharged from the first compressor 21 should be supplied to the indoor unit 4a, and determines that the refrigerant discharged from the second compressor 21 should be supplied to the indoor unit 4b. . It is assumed that the difference between the air conditioning load (cooling load) for the indoor unit 4c and the air conditioning load (cooling load) for the indoor unit 4d is less than a predetermined value.

  Next, in step S106, the controller 50 sets the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor 21 and the evaporation temperature or evaporation pressure of the refrigerant discharged from the second compressor 31. Determine the target value. At this time, the controller 50 sets the target value of the evaporating temperature or evaporating pressure of the refrigerant discharged from the first compressor 21 and the target value of the evaporating temperature or evaporating pressure of the refrigerant discharged from the second compressor 31. The target value is determined to be different. For example, the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor 21 is lower than the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the second compressor 31. Thereby, the cooling capability exhibited by the indoor unit 4a and the cooling capability exhibited by the indoor unit 4b can be made different. Refrigerant in a state desirable for the cooling load for the indoor unit 4a and the cooling load for the indoor unit 4b can be supplied to the indoor unit 4a and the indoor unit 4b, respectively.

  Next, in step S107, the controller 50 controls the flow path switching mechanism 30 so that the second state is formed according to the determination in step S105. Specifically, the controller 50 operates the flow path switching mechanism 30 of the refrigerant distribution unit 3a by opening the first low pressure switching valve 37a, closing the second low pressure switching valve 37b, and closing the third low pressure switching valve 37c. The fourth low pressure switching valve 37d is opened, the first high pressure switching valve 38a is opened, the second high pressure switching valve 38b is closed, the third high pressure switching valve 38c is closed, and the fourth high pressure switching valve 38d is opened. Thus, the flow path switching mechanism 30 is controlled. Further, the controller 50 controls the four-way valve 25 and the four-way valve 35 so that the four-way valve 25 and the four-way valve 35 form a flow path indicated by a solid line in FIG.

  Next, in step S108, the controller 50 controls the rotational speed of the first compressor 21 based on the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor 21 determined in step S106. To do. In step S108, the controller 50 controls the rotational speed of the second compressor 31 based on the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the second compressor 31 determined in step S106. . For example, the controller 50 detects the representative value of the temperature of the refrigerant liquid in the indoor heat exchanger 43 belonging to the indoor unit 4a, which is detected by the liquid temperature sensor 45b, of the evaporation temperature of the refrigerant discharged from the first compressor 21. The rotation speed of the first compressor 21 is controlled so as to approach the target value. Further, the controller 50 indicates that the representative value of the temperature of the refrigerant liquid in the indoor heat exchanger 43 belonging to the indoor unit 4b detected by the liquid temperature sensor 45b is the evaporation temperature of the refrigerant discharged from the second compressor 31. The rotational speed of the second compressor 21 is controlled so as to approach the target value. In this way, the cooling operation in the non-uniform load mode is performed.

  In this case, in the air conditioner 1a, the refrigerant flows as shown in FIG. The thick line in FIG. 5 indicates the flow path through which the refrigerant flows, and the arrow in FIG. 5 indicates the direction in which the refrigerant flows. The refrigerant discharged from the first compressor 21 is in a uniform load mode, except that the refrigerant supplied to the refrigerant distribution unit 3a passes only through the indoor unit 4a and returns to the outdoor unit 2 without passing through the indoor unit 4b. It flows in the same way as during cooling operation. The second compressor 31 of the refrigerant distribution unit 3a is operating. The refrigerant discharged from the second compressor 31 of the refrigerant distribution unit 3a passes through the four-way valve 35 and exchanges heat with air passing through the second heat exchanger 32 by the function of the blower 33 in the second heat exchanger 32. Condensed. The condensed liquid refrigerant is decompressed by the second decompression mechanism 34, passes through the fourth low-pressure switching valve 37d, flows through the second connection liquid channel 14b, and is supplied to the indoor unit 4b. The refrigerant supplied to the indoor unit 4b is decompressed by passing through the flow rate adjusting valve 42, and evaporates by exchanging heat with the indoor air sucked by the indoor blower 43 in the indoor heat exchanger 41. As a result, the room air is cooled, and the cooled room air is returned to the room for cooling. The refrigerant that has flowed out of the indoor unit 4b passes through the fourth high-pressure switching valve 38d and the four-way valve 35 and flows into the accumulator 36. The refrigerant adjusted to an appropriate dryness in the accumulator 36 is sucked into the second compressor 31.

  Here, the controller 50 changes the target value of the evaporating temperature or evaporating pressure of the refrigerant discharged from the first compressor 21 in accordance with the change in the air conditioning load (cooling load) on the indoor unit 4a, and the changed The rotational speed of the first compressor 21 is controlled according to the target value. Further, the target value of the evaporating temperature or evaporating pressure of the refrigerant discharged from the second compressor 31 is changed according to the change in the air conditioning load (cooling load) on the indoor unit 4b, and the second compression is performed according to the changed target value. The rotation speed of the machine 21 is controlled. Furthermore, when the difference between the air conditioning load (cooling load) for the indoor unit 4a and the air conditioning load (cooling load) for the indoor unit 4b is less than a predetermined value, the controller 50 acts to cool the air in the non-uniform load mode. Transition from operation to cooling operation in uniform load mode.

(Heating operation in uniform load mode)
As shown in FIG. 3, when the determination in step S101 is negative (No), the controller 50 proceeds to step S111 and determines whether or not the requests from all the indoor units 4a to 4d are heating. to decide. If the determination in step S111 is affirmative (Yes), the controller 50 executes the processes of steps S301 and S302 as shown in FIG. That is, the controller 50 acquires the temperature Tac detected by the suction temperature sensor 47a included in each of the indoor units 4a to 4d. Then, the air conditioning load (heating load) for each indoor unit 4a to 4d is calculated based on the difference between the temperature Tac in each indoor unit 4a to 4d and the set temperature Tset of the indoor air in each indoor unit 4a to 4d. Specifically, the controller 50 calculates the air conditioning load (heating load) for each of the indoor units 4a to 4d based on the change over time of the difference between the temperature Tac and the set temperature Tset in each of the indoor units 4a to 4d. The controller 50 determines which of the first state and the second state should be formed based on the calculated air conditioning load (heating load) for each of the indoor units 4a to 4d. Specifically, in step S303, the controller 50 determines whether or not the difference in air conditioning load (heating load) for each of the indoor units 4a to 4d is greater than or equal to a predetermined value. For example, the controller 50 determines whether or not the difference between the air conditioning load (heating load) for the indoor unit 4a and the air conditioning load (heating load) for the indoor unit 4b is equal to or greater than a predetermined value, or air conditioning for the indoor unit 4c. It is determined whether the difference between the load (heating load) and the air conditioning load (heating load) for the indoor unit 4d is equal to or greater than a predetermined value.

  If the determination in step S303 is negative (No), the controller 50 determines that the first state should be formed. In this case, in step S311, the controller 50 sets the target value of the condensation temperature or condensation pressure of the refrigerant discharged from the first compressor 21 based on the air conditioning load (heating load) for each of the indoor units 4a to 4d. decide. In step S312, the controller 50 controls the flow path switching mechanism 30 so that the first state is formed. Specifically, the controller 50 has the first low pressure switching valve 37a opened, the second low pressure switching valve 37b opened, the third low pressure switching valve 37c closed, the fourth low pressure switching valve 37d closed, The flow path switching mechanism 30 is controlled so that the one high pressure switching valve 38a is opened, the second high pressure switching valve 38b is opened, the third high pressure switching valve 38c is closed, and the fourth high pressure switching valve 38d is closed. In addition, in step S313, the controller 50 determines the rotation speed of the first compressor 21 based on the target value of the condensing temperature or condensing pressure of the refrigerant discharged from the first compressor 21 determined in step S312. To control. At this time, the controller 50 controls the four-way valve 25 so that the four-way valve 25 forms a flow path indicated by a broken line in FIG. Thereby, the heating operation in a 1st state is performed in the air conditioning apparatus 1a. In other words, the heating operation in the uniform load mode is performed.

  When the heating operation in the uniform load mode is performed, the refrigerant flows in the air conditioner 1a as shown in FIG. The thick line in FIG. 7 shows the flow path through which the refrigerant flows, and the arrow in FIG. 7 shows the direction in which the refrigerant flows. The gas refrigerant discharged from the first compressor 21 passes through the four-way valve 25 and the common gas flow path 12, and flows into the second relay flow path 13b of the refrigerant distribution unit 3a or the refrigerant distribution unit 3b. The refrigerant flowing into the second relay flow path 13a of the refrigerant distribution unit 3a is supplied to the indoor unit 4a via the first high pressure switching valve 38a and the first connection gas flow path 15a, or the second high pressure switching valve 38b. And it is supplied to the indoor unit 4b via the second connection gas flow path 15b. The refrigerant flowing into the second relay flow path 13b of the refrigerant distribution unit 3b is supplied to the indoor unit 4c via the first high pressure switching valve 38a and the third connection gas flow path 15c, or the second high pressure switching valve 38b. And it is supplied to the indoor unit 4d via the fourth connection gas flow path 15d. The refrigerant supplied to each of the indoor units 4 a to 4 d is condensed by exchanging heat with the indoor air sucked by the indoor blower 43 in the indoor heat exchanger 41. As a result, the room air is heated, and the heated room air is returned to the room for heating. The refrigerant flowing out of the indoor heat exchanger 41 is decompressed by passing through the flow rate adjustment valve 42. The opening degree of the flow rate adjustment valve 42 is adjusted so that the refrigerant after passing through the flow rate adjustment valve 42 has an appropriate degree of supercooling. The refrigerant that has flowed out of each of the indoor units 4a to 4d flows through the first connection liquid flow path 14a, the second connection liquid flow path 14b, the third connection liquid flow path 14c, or the fourth connection liquid flow path 14d, the first low pressure switching valve. 37a or the second low pressure switching valve 37b, the first relay flow path 13a, and the common liquid flow path 11 are returned to the outdoor unit 2. The refrigerant returned to the outdoor unit 2 is decompressed by the first decompression mechanism 24 and is evaporated by exchanging heat with outdoor air in the first heat exchanger 22. The evaporated refrigerant passes through the four-way valve 25 and flows into the accumulator 26. The refrigerant adjusted to an appropriate dryness in the accumulator 26 is sucked into the first compressor 21. At this time, the second compressor 31 is stopped.

  Here, the controller 50 changes the target value of the condensing temperature or condensing pressure of the refrigerant discharged from the first compressor 21 according to the change in the air conditioning load (cooling load) for each of the indoor units 4a to 4d, The rotational speed of the first compressor 21 is controlled according to the changed target value. For example, when the air-conditioning load (heating load) with respect to each indoor unit 4a-4d falls, the rotation speed of the 1st compressor 21 is reduced. In this case, the number of heat exchanged in the first heat exchanger 22 may be reduced by reducing the rotational speed of the outdoor blower 23 so that the blown amount of the outdoor blower 23 is lowered. Moreover, when the air conditioning apparatus 1a includes a plurality of outdoor units 2, when the air conditioning load on each of the indoor units 4a to 4d becomes extremely small with respect to the capacity of the outdoor unit 2, a part of the outdoor unit 2 is operated. May be stopped. When the variation of the air conditioning load (heating load) for each of the indoor units 4a to 4d is large, the controller 50 shifts the heating operation in the uniform load mode to the heating operation in the non-uniform load mode.

(Heating operation in non-uniform load mode)
If the determination in step S303 is affirmative (Yes), the controller 50 determines that the second state should be formed. In this case, it is determined whether the refrigerant discharged from the first compressor 21 or the second compressor 31 should be supplied to each of the indoor units 4a to 4d, and the second state is formed according to these determinations. Thus, the flow path switching mechanism 30 is controlled. At this time, the controller 50 controls the four-way valve 25 and the four-way valve 35 so that the four-way valve 25 and the four-way valve 35 form a flow path indicated by a broken line in FIG. Thereby, in the air conditioning apparatus 1a, heating operation is performed in a 2nd state. In other words, the heating operation in the non-uniform load mode is performed.

  In addition, the controller 50 performs the target value of the condensation temperature or the condensation pressure of the refrigerant discharged from the first compressor 21 and the refrigerant discharged from the second compressor 31 when the heating operation is performed in the second state. The target values for the condensation temperature or pressure are determined such that these target values are different. Then, the controller 50 controls the rotational speed of the first compressor 21 and the rotational speed of the second compressor 31 based on these determined target values.

  When the heating operation is performed in the second state, the controller 50 determines the refrigerant saturation temperature calculated based on the pressure detected by the first discharge pressure sensor 29a of the refrigerant discharged from the first compressor 21. The rotation speed of the first compressor 21 is controlled so as to approach the target value of the condensation temperature. In addition, the controller 50 sets the refrigerant saturation temperature calculated based on the pressure detected by the second discharge pressure sensor 39b so as to approach the target value of the refrigerant condensation temperature discharged from the second compressor 31. The rotational speed of the two compressors 31 is controlled. The saturation temperature of the refrigerant calculated based on the pressure detected by the first discharge pressure sensor 29a is, for example, the saturation temperature of the refrigerant at the pressure detected by the first discharge pressure sensor 29a. In addition to the pressure detected by the first discharge pressure sensor 29a, the saturation temperature of the refrigerant is calculated in consideration of the pressure loss of the refrigerant flow estimated from the estimated pipe length and the refrigerant flow rate. May be. The saturation temperature of the refrigerant calculated based on the pressure detected by the second discharge pressure sensor 39b is, for example, the saturation temperature of the refrigerant at the pressure detected by the second discharge pressure sensor 39b. In addition to the pressure detected by the second discharge pressure sensor 39b, the saturation temperature of the refrigerant is calculated in consideration of the pressure loss of the refrigerant flow estimated from the estimated pipe length and the refrigerant flow rate. May be.

  Specifically, as shown in FIG. 6, the controller 50 supplies the refrigerant discharged from either the first compressor 21 or the second compressor 31 to each of the indoor units 4a to 4d in step S304. Decide what to do. For example, the controller 50 determines that the refrigerant discharged from the first compressor 21 should be supplied to an indoor unit that receives a larger air conditioning load (heating load) among the indoor units 4a and 4b. Moreover, the controller 50 determines that the refrigerant | coolant discharged from the 2nd compressor 31 should be supplied to the indoor unit which receives smaller air conditioning load (heating load) among the indoor units 4a and 4b. Here, it is assumed that the air conditioning load (heating load) for the indoor unit 4a is larger than the air conditioning load (heating load) for the indoor unit 4b by a predetermined value or more. The controller 50 determines that the refrigerant discharged from the first compressor 21 should be supplied to the indoor unit 4a, and determines that the refrigerant discharged from the second compressor 31 should be supplied to the indoor unit 4b. . It is assumed that the difference between the air conditioning load (cooling load) for the indoor unit 4c and the air conditioning load (cooling load) for the indoor unit 4d is less than a predetermined value.

  Next, in step S <b> 305, the control unit 50 sets the target value of the condensation temperature or condensation pressure of the refrigerant discharged from the first compressor 21 and the condensation temperature or condensation pressure of the refrigerant discharged from the second compressor 31. Determine the target value. At this time, the controller 50 sets the target value of the condensing temperature or condensing pressure of the refrigerant discharged from the first compressor 21 and the target value of the condensing temperature or condensing pressure of the refrigerant discharged from the second compressor 31. The target value is determined to be different. For example, the target value of the condensation temperature or condensation pressure of the refrigerant discharged from the first compressor 21 is higher than the target value of the condensation temperature or condensation pressure of the refrigerant discharged from the second compressor 31. Thereby, the heating capability which the indoor unit 4a exhibits, and the heating capability which the indoor unit 4b exhibits can be varied. Refrigerant in a state desirable for the heating load on the indoor unit 4a and the heating load on the indoor unit 4b can be supplied to the indoor unit 4a and the indoor unit 4b, respectively.

  Next, in step S306, the controller 50 controls the flow path switching mechanism 30 so that the second state is formed according to the determination in step S304. Specifically, the controller 50 operates the flow path switching mechanism 30 of the refrigerant distribution unit 3a by opening the first low pressure switching valve 37a, closing the second low pressure switching valve 37b, and closing the third low pressure switching valve 37c. The fourth low pressure switching valve 37d is opened, the first high pressure switching valve 38a is opened, the second high pressure switching valve 38b is closed, the third high pressure switching valve 38c is closed, and the fourth high pressure switching valve 38d is opened. To control.

  Next, in step S307, the controller 50 controls the rotational speed of the first compressor 21 based on the target value of the condensing temperature or condensing pressure of the refrigerant discharged from the first compressor 21 determined in step S305. To do. Moreover, the controller 50 controls the rotation speed of the 2nd compressor 31 based on the target value of the condensation temperature or the condensation pressure of the refrigerant | coolant discharged from the 2nd compressor 31 determined by step S305 in step S307. .

  In this case, in the air conditioner 1a, the refrigerant flows as shown in FIG. The thick line in FIG. 8 indicates the flow path through which the refrigerant flows, and the arrow in FIG. 8 indicates the direction in which the refrigerant flows. The refrigerant discharged from the first compressor 21 is in a uniform load mode, except that the refrigerant supplied to the refrigerant distribution unit 3a passes only through the indoor unit 4a and returns to the outdoor unit 2 without passing through the indoor unit 4b. It is flowing in the same way as the heating operation. The second compressor 31 of the refrigerant distribution unit 3a is operating. The refrigerant discharged from the second compressor 31 of the refrigerant distribution unit 3a passes through the four-way valve 35, the fourth high-pressure switching valve 38d, and the second connection gas flow path 15b and flows into the indoor unit 4b. The refrigerant flowing into the indoor unit 4b is condensed by exchanging heat with the indoor air sucked in by the indoor blower 43 in the indoor heat exchanger 41. The refrigerant flowing out of the indoor heat exchanger 41 is decompressed by passing through the flow rate adjustment valve 42. The refrigerant that has flowed out of the indoor unit 4b passes through the second connection liquid channel 14b and the fourth low-pressure switching valve 37d, and is further depressurized by passing through the second pressure reducing mechanism 34. The decompressed refrigerant evaporates by exchanging heat with outdoor air in the second heat exchanger 32. The evaporated refrigerant passes through the four-way valve 35 and flows into the accumulator 36. The refrigerant adjusted to an appropriate dryness in the accumulator 36 is sucked into the second compressor 31.

  Here, the controller 50 changes the target value of the condensing temperature or condensing pressure of the refrigerant discharged from the first compressor 21 according to the change of the air conditioning load (heating load) on the indoor unit 4a, and the changed Based on the target value, the rotational speed of the first compressor 21 is controlled. Moreover, the target value of the refrigerant | coolant condensing temperature or the condensing pressure discharged from the 2nd compressor 31 is changed according to the change of the air-conditioning load (heating load) with respect to the indoor unit 4b, and 2nd compression is carried out according to the changed target value. The rotation speed of the machine 21 is controlled. Furthermore, when the difference between the air conditioning load (heating load) for the indoor unit 4a and the air conditioning load (heating load) for the indoor unit 4b becomes less than a predetermined value, the controller 50 performs the heating in the non-uniform load mode. Transition from operation to heating operation in uniform load mode.

(Simultaneous cooling and heating)
The controller 50 performs the following control when a cooling operation is performed in some of the plurality of indoor units 4a to 4d and a heating operation is performed in another part of the plurality of indoor units 4a to 4d. . The controller 50 controls the flow path switching mechanism 30 so as to form the next second state when the capacity of the indoor unit in which the cooling operation is performed is larger than the capacity of the indoor unit in which the heating operation is performed. In the second state, the refrigerant discharged from the first compressor 21 is supplied to the indoor unit in which the cooling operation is performed, and the refrigerant discharged from the second compressor 31 is supplied to the indoor unit in which the heating operation is performed. Is the state. At this time, the controller 50 controls the four-way valve 25 so that the four-way valve 25 forms a flow path indicated by a solid line in FIG. 1, and the four-way valve 35 forms a flow path indicated by a broken line in FIG. The four-way valve 35 is controlled. In addition, when the cooling operation or the heating operation is performed in a plurality of indoor units among the three or more indoor units connected to each refrigerant distribution unit, the sum of the capacities of the plurality of indoor units in which the cooling operation or the heating operation is performed. Is defined as the capacity of the indoor unit in which cooling operation or heating operation is performed.

  The controller 50 controls the flow path switching mechanism 30 to form the next second state when the capacity of the indoor unit in which the cooling operation is performed is smaller than the capacity of the indoor unit in which the heating operation is performed. In the second state, the refrigerant discharged from the second compressor 31 is supplied to the indoor unit in which the cooling operation is performed, and the refrigerant discharged from the first compressor 21 is supplied to the indoor unit in which the heating operation is performed. Is the state. At this time, the controller 50 controls the four-way valve 25 so that the four-way valve 25 forms a flow path indicated by a broken line in FIG. 1, and the four-way valve 35 forms a flow path indicated by a solid line in FIG. The four-way valve 35 is controlled.

  If the determination in step S111 is negative (No), the controller 50 proceeds to step S401 as shown in FIG. It is assumed that the cooling operation is performed in the indoor unit 4a and the heating operation is performed in the indoor unit 4b. In the indoor unit 4c and the indoor unit 4d, it is assumed that the cooling operation is performed and the refrigerant flows similarly to the cooling operation in the uniform load mode. In step S401, the controller 50 acquires the capacity of the indoor unit 4a that performs cooling and the capacity of the indoor unit 4b that performs heating. Next, in step S402, the controller 50 determines whether or not the capacity of the indoor unit 4a that performs cooling is greater than the capacity of the indoor unit 4b that performs heating. If the determination in step S402 is affirmative (Yes), the controller 50 proceeds to step S403 and controls the flow path switching mechanism 30 so as to form the next second state. The second state is that the refrigerant discharged from the first compressor 21 is supplied to the indoor unit 4a in which cooling is performed, and the refrigerant discharged from the second compressor 31 is in the indoor unit 4b in which heating is performed. Supplied, state. The controller 50 moves the flow path switching mechanism 30 of the refrigerant distribution unit 3a through the first low pressure switching valve 37a, the second low pressure switching valve 37b, the third low pressure switching valve 37c, and the fourth low pressure. The switching valve 37d is opened, the first high pressure switching valve 38a is opened, the second high pressure switching valve 38b is closed, the third high pressure switching valve 38c is closed, and the fourth high pressure switching valve 38d is opened. To do. Next, the controller 50 controls the rotation speed of the first compressor 21 based on the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor 21 in step S404. Moreover, the controller 50 controls the rotation speed of the 2nd compressor 31 based on the target value of the condensation temperature or the condensation pressure of the refrigerant | coolant discharged from the 2nd compressor 31 in step S404.

  When the determination in step S402 is negative (No), the controller 50 proceeds to step S411 and controls the flow path switching mechanism 30 so as to form the next second state. The second state is that the refrigerant discharged from the second compressor 31 is supplied to the indoor unit 4a in which cooling is performed, and the refrigerant discharged from the first compressor 21 is in the indoor unit 4b in which heating is performed. Supplied, state. The controller 50 operates the flow path switching mechanism 30 of the refrigerant distribution unit 3a by closing the first low pressure switching valve 37a, opening the second low pressure switching valve 37b, opening the third low pressure switching valve 37c, and opening the fourth low pressure switching valve. Control is performed so that the switching valve 37d is closed, the first high-pressure switching valve 38a is closed, the second high-pressure switching valve 38b is opened, the third high-pressure switching valve 38c is opened, and the fourth high-pressure switching valve 38d is closed. To do. Next, the controller 50 controls the rotation speed of the first compressor 21 based on the target value of the condensation temperature or the condensation pressure of the refrigerant discharged from the first compressor 21 in step S412. Moreover, the controller 50 controls the rotation speed of the 2nd compressor 31 based on the target value of the evaporating temperature or evaporating pressure of the refrigerant | coolant discharged from the 2nd compressor 31 in step S412. In this way, the cooling operation is performed by the indoor unit 4a, and the heating operation is performed by the indoor unit 4b.

  In the simultaneous cooling / heating operation when the cooling capacity of the indoor unit 4a is larger than the heating capacity of the indoor unit 4b, the refrigerant flows as shown in FIG. The refrigerant discharged from the first compressor 21 flows in the same manner as the refrigerant flow between the outdoor unit 2 and the indoor unit 4a in the cooling operation in the uniform load mode. The refrigerant discharged from the second compressor 31 flows in the same manner as the refrigerant flow in the heating operation in the non-uniform load mode.

  When the process of step S404 is performed by the controller 50, it is conceivable that the magnitude relationship between the capacity of the indoor unit in which the cooling operation is performed and the capacity of the indoor unit in which the heating operation is performed is reversed. In this case, the process of step S404 is not continued immediately, but the process of step S404 is continued until the capacity of the indoor unit in which the cooling operation is performed becomes equal to or greater than the capacity of the indoor unit in which the heating operation is performed. Is done. Moreover, when the process of step S412 is performed by the controller 50, it is conceivable that the magnitude relationship between the capacity of the indoor unit in which the cooling operation is performed and the capacity of the indoor unit in which the heating operation is performed is reversed. In this case, the process of step S412 is not ended immediately, but the process of step S412 is continued until the capacity of the indoor unit in which the cooling operation is performed becomes larger than the capacity of the indoor unit in which the heating operation is performed by a predetermined value or more. Is done. Thereby, the cooling is performed by the refrigerant discharged from the first compressor 21 and the heating is performed by the refrigerant discharged from the second compressor 31, and the refrigerant discharged from the first compressor 21. It is possible to prevent frequent switching between a state where heating is performed and cooling is performed by the refrigerant discharged from the second compressor 31.

<Modification>
The air conditioner 1a can be changed from various viewpoints. The air conditioner 1a may be changed like an air conditioner 1b shown in FIG. The air conditioner 1b is configured in the same manner as the air conditioner 1a unless otherwise described. Of the components in the air conditioner 1b, the same or corresponding components as those in the air conditioner 1a are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 11, the air conditioner 1 b further includes a humidity adjuster 70. The humidity controller 70 is disposed downstream of the second heat exchanger 32 in the flow direction of the fluid that exchanges heat with the refrigerant in the second heat exchanger 32. Here, the fluid that exchanges heat with the refrigerant in the second heat exchanger 32 is, for example, air. The humidity controller 70 has a desiccant 71 for absorbing or releasing moisture. The desiccant 71 normally has a characteristic of absorbing moisture and releasing the moisture absorbed by heating. The humidity adjuster 70 is configured such that the air flow that has passed through the second heat exchanger 32 can flow in contact with the desiccant 71. In FIG. 11, thick arrows indicate the flow of air. This air flow is created by the blower 33. The blower 33 is configured, for example, so as to create a flow of air that is sucked from outside the room and flows into the predetermined room through the second heat exchanger 32 and the temperature regulator 70. The blower 33 may be configured so that air sucked from a predetermined room creates a flow of air that passes through the second heat exchanger 32 and the temperature regulator 70 and flows to the outside.

  When the second compressor 31 is operated and the four-way valve 35 forms a flow path indicated by a broken line in FIG. 11, the second heat exchanger 32 functions as an evaporator. In this case, the air is cooled by passing through the second heat exchanger 32, and moisture in the cooled air is absorbed by the desiccant 71 in the humidity controller 70. In this way, the air that has passed through the humidity controller 70 is dehumidified. For example, if the flow path is configured so that the dehumidified air is supplied into the room, the room air can be dehumidified. Moreover, when the air sucked from the outside by the function of the blower 33 passes through the humidity controller 70, moisture contained in the air sucked from the outside can be collected by the temperature controller 70. Furthermore, when the air sucked from the predetermined room by the function of the blower 33 passes through the humidity controller 70 and flows to the outside, moisture contained in the predetermined room air can be released to the outside.

  When the second compressor 31 is activated and the four-way valve 35 forms a flow path indicated by a solid line in FIG. 11, the second heat exchanger 32 functions as a condenser. In this case, the air is heated by passing through the second heat exchanger, and the moisture absorbed in the desiccant 71 is released by the heated air flowing through the humidity regulator 70. Thereby, indoor air can be humidified if a flow path is comprised so that the air containing the discharge | released water | moisture content may be supplied indoors.

1a, 1b Air conditioner 2 Outdoor unit 3a, 3b Refrigerant distribution unit 4a-4d Indoor unit 21 First compressor 22 First heat exchanger 24 First decompression mechanism 29a First discharge pressure sensor 29b First suction pressure sensor 30 Flow Path switching mechanism 31 Second compressor 32 Second heat exchanger 34 Second pressure reducing mechanism 39b Second discharge pressure sensor 39c Second suction pressure sensor 41 Indoor heat exchanger 42 Flow rate adjusting valve 45b Liquid temperature sensor 47a Suction temperature sensor 50 Control 70 Humidity adjuster 71 Desiccant

Claims (14)

An outdoor unit including a first compressor, a first heat exchanger, and a first pressure reduction mechanism;
A plurality of indoor units including an indoor heat exchanger and a flow control valve;
The second compressor, the second heat exchanger, the second pressure reducing mechanism, and the refrigerant discharged from the first compressor are supplied to all of the plurality of indoor units and returned to the first compressor. The refrigerant discharged from the first compressor is supplied to a part of the plurality of indoor units and returned to the first compressor, and the refrigerant discharged from the second compressor is A flow path switching mechanism for switching between a second state supplied to another part of the plurality of indoor units and returned to the second compressor, between the outdoor unit and the plurality of indoor units A refrigerant distribution unit configured to form a refrigerant circuit at
Air conditioner. A suction temperature sensor for detecting the temperature of the indoor air sucked into each indoor unit;
The air conditioning load for each indoor unit is calculated based on the difference between the temperature detected by the suction temperature sensor included in each indoor unit and the set temperature of the indoor air in each indoor unit, and the calculated air conditioning for each indoor unit Based on the load, it is determined which of the first state and the second state is to be formed, and when it is determined that the second state is to be formed, each indoor unit is provided with the first compressor and the second state. And a controller that determines which of the compressors should be supplied with refrigerant discharged and controls the flow path switching mechanism so that the second state is formed according to these determinations. Item 2. The air conditioner according to Item 1.   When the cooling operation is performed in the second state, the controller is configured to evaporate the refrigerant discharged from the second compressor and the target value of the evaporation temperature or evaporation pressure of the refrigerant discharged from the first compressor. The target value of temperature or evaporating pressure is determined so that these target values are different, and the rotational speed of the first compressor and the rotational speed of the second compressor are controlled based on the determined target values. The air conditioning apparatus according to claim 2. A liquid temperature sensor for detecting the temperature of the refrigerant liquid in the indoor heat exchanger of each indoor unit;
The controller detects the indoor heat exchange belonging to the indoor unit supplied with the refrigerant discharged from the first compressor, which is detected by the liquid temperature sensor when the cooling operation is performed in the second state. The number of revolutions of the first compressor is controlled so that the representative value of the temperature of the refrigerant liquid in the compressor approaches the target value of the evaporation temperature of the refrigerant discharged from the first compressor, and the liquid temperature sensor The representative value of the temperature of the refrigerant liquid in the indoor heat exchanger belonging to the indoor unit to which the refrigerant discharged from the second compressor is supplied is detected by the refrigerant discharged from the second compressor. The refrigeration cycle apparatus according to claim 3, wherein the rotation speed of the second compressor is controlled so as to approach the target value of the evaporation temperature. A first suction pressure sensor for detecting the suction pressure of the refrigerant into the first compressor;
A second suction pressure sensor for detecting the suction pressure of the refrigerant into the second compressor,
The controller is configured such that when the cooling operation is performed in the second state, the saturation temperature of the refrigerant calculated based on the pressure detected by the first suction pressure sensor is discharged from the first compressor. The rotation speed of the first compressor is controlled so as to approach the target value of the evaporation temperature of the refrigerant, and the saturation temperature of the refrigerant calculated based on the pressure detected by the second suction pressure sensor is The air conditioning apparatus according to claim 3, wherein the rotational speed of the second compressor is controlled so as to approach the target value of the evaporation temperature of the refrigerant discharged from the compressor.   The controller is configured to condense the refrigerant discharged from the second compressor and the target value of the condensation temperature or condensation pressure of the refrigerant discharged from the first compressor when the heating operation is performed in the second state. The target value of the temperature or the condensation pressure is determined so that these target values are different, and the rotational speed of the first compressor and the rotational speed of the second compressor are controlled based on the determined target values. The air conditioning apparatus according to claim 2. A first discharge pressure sensor for detecting the discharge pressure of the refrigerant from the first compressor;
A second discharge pressure sensor for detecting the discharge pressure of the refrigerant from the second compressor,
The controller is configured such that when the heating operation is performed in the second state, the refrigerant saturation temperature calculated based on the pressure detected by the first discharge pressure sensor is discharged from the first compressor. The rotation speed of the first compressor is controlled so as to approach the target value of the condensing temperature of the refrigerant, and the saturation temperature of the refrigerant calculated based on the pressure detected by the second discharge pressure sensor is the second The air conditioning apparatus according to claim 6, wherein the rotation speed of the second compressor is controlled so as to approach the target value of the condensation temperature of the refrigerant discharged from the compressor.   When the cooling operation is performed in a part of the plurality of indoor units and the heating operation is performed in the other part of the plurality of indoor units, the capacity of the indoor unit in which the cooling operation is performed is the heating operation. When the capacity of the indoor unit is larger than the capacity of the indoor unit, the refrigerant discharged from the first compressor is supplied to the indoor unit in which the cooling operation is performed, and the second compression is performed in the indoor unit in which the heating operation is performed. The air conditioning apparatus according to claim 1, further comprising a controller that controls the flow path switching mechanism so as to form the second state in which a refrigerant discharged from the machine is supplied.   The controller is discharged from the second compressor to the indoor unit in which the cooling operation is performed when the capacity of the indoor unit in which the cooling operation is performed is smaller than the capacity of the indoor unit in which the heating operation is performed. The flow path switching mechanism is controlled so as to form the second state in which the refrigerant discharged from the first compressor is supplied to the indoor unit in which the heating operation is performed. The air conditioning apparatus according to claim 8.   The humidity controller further comprising a desiccant that is disposed downstream of the second heat exchanger in a flow direction of a fluid that exchanges heat with the refrigerant in the second heat exchanger and has a desiccant to absorb or release moisture. The air conditioning apparatus according to any one of 1 to 9.   The air conditioning apparatus according to any one of claims 1 to 10, wherein the refrigerant is a refrigerant having a global warming potential of 2090 or less.   The air conditioning apparatus according to any one of claims 1 to 10, wherein the refrigerant is a natural refrigerant.   The air conditioning apparatus according to any one of claims 1 to 10, wherein the refrigerant is a refrigerant mainly composed of fluorocarbon. A refrigerant distribution unit to be incorporated in an air conditioner having an outdoor unit including a first compressor, a first heat exchanger, and a first pressure reducing mechanism, and a plurality of indoor units including an indoor heat exchanger and an indoor expansion valve. There,
A second compressor,
A second heat exchanger;
A second decompression mechanism;
A first state in which the refrigerant discharged from the first compressor is supplied to all of the plurality of indoor units and returned to the first compressor when incorporated in the air conditioner; and the first compression The refrigerant discharged from the unit is supplied to a part of the plurality of indoor units and returned to the first compressor, and the refrigerant discharged from the second compressor is another one of the plurality of indoor units. A flow path switching mechanism for switching between a second state supplied to the unit and returned to the second compressor,
A refrigerant distribution unit configured to form a refrigerant circuit between the outdoor unit and the plurality of indoor units when incorporated in the air conditioner.

Images