JP5137933B2 - Air conditioner - Google Patents

Description

  The present invention relates to a multi-system air conditioner in which a plurality of usage units are connected and cooling operation or heating operation is possible in each usage unit, and particularly relates to control of a compressor, an outdoor blower, or an indoor decompression mechanism. It is.

  As a conventional air conditioner, there is a separate type multi-system air conditioner in which a refrigerant circuit is configured by connecting a plurality of heat source units and a utilization unit via a connection pipe. An example of the separate type multi-system air conditioner is a packaged air conditioner.

  There are also multi-system air conditioners that can simultaneously handle cooling and heating loads. Such an air conditioner is generally configured by connecting a plurality of use units (indoor units) to a heat source unit (outdoor unit) via a connection pipe (refrigerant pipe). The cooling operation and heating operation selected in the unit can be performed simultaneously.

Japanese Patent Publication No.8-30626 (FIG. 1) Japanese Patent No. 2564905 (FIG. 1) Japanese Patent Publication No. 7-62569 (FIG. 1) Japanese Patent No. 4179983 (FIG. 1) Japanese Patent No. 2716559 (FIG. 1)

  As a conventional control method for a multi-system air conditioner, Patent Document 1 detects a temperature difference between a room setting temperature of a usage unit and a room temperature, and uses a decompression mechanism opening degree of the usage unit having a relatively large load fluctuation as a load fluctuation. In addition, the operation of suppressing the fluctuation of the operating frequency of the compressor is performed by changing the decompression mechanism opening of the remaining usage units so that the total value of the decompression mechanism opening of each usage unit becomes constant. It was.

  In addition, in the control at the time of cooling and heating simultaneous operation in Patent Document 2, when the total value of the required heating capacity is large, the high pressure side pressure is controlled by the compressor and the low pressure side pressure is controlled by the pressure reducing mechanism, and the total cooling required capacity is calculated. When the value is large, the low pressure side pressure is controlled by a compressor, and the high pressure side pressure is controlled by a pressure reducing mechanism, thereby satisfying the required capacity of each indoor unit and performing air conditioning.

  However, in these conventional methods, since the change in the air conditioning load is accommodated by the change in the opening of the decompression mechanism, which is the role of distributing the refrigerant flow rate, the control for reducing the opening of the decompression mechanism when the air conditioning load is small. Therefore, since the resistance is increased, the operation frequency of the compressor is excessively increased, resulting in a decrease in operation efficiency.

  In the control during simultaneous cooling and heating in Patent Document 3, the required capacity is calculated from the difference between the set temperature and the intake air temperature in each use unit, and the physical state quantity satisfying the required capacity (evaporation temperature during cooling operation). The condensation temperature during heating operation is calculated. The operating frequency of the compressor is controlled based on the physical state quantity corresponding to the maximum required capacity among the physical state quantities of each used unit, and the decompression mechanism controls the opening by the required capacity of the used unit. Was prevented from falling. However, in this method, only one of the evaporation temperature and the condensation temperature is controlled, and both are not controlled. Therefore, the condensation temperature increases during the cooling operation, and the evaporation temperature decreases during the heating operation. There was a possibility of incurring a decline.

  In the control of simultaneous cooling and heating in Patent Document 4, the total cooling load and the total heating load are calculated from the cooling load or heating load of each usage unit, the compressor is controlled by the larger total air conditioning load, and the smaller one is calculated. The evaporating temperature and the condensing temperature are controlled by controlling the heat exchange capacity of the outdoor heat exchanger (for example, the air volume of the outdoor fan) with the total air conditioning load. However, since the control is based on the total air conditioning load, for example, when a usage unit with a small required capacity is connected, or when the number of usage units connected is large, the required capacity of the usage units per unit is the total value. However, when the air conditioner load is relatively small, the compressor and the outdoor fan do not operate with respect to fluctuations in the air conditioning load. Further, since the evaporating pressure or the condensing pressure is a fixed state quantity for each usage unit, there may be a case where it is not possible to achieve an operation state that satisfies the air conditioning load of all the usage units. Therefore, when the air conditioning load is large in a certain usage unit, it is limited to the air conditioning capacity determined by the evaporating pressure during cooling operation and the condensation pressure during heating operation, and it is not possible to exert more capacity, It was unwarming. On the other hand, when the air conditioning load is small, the pressure reducing mechanism opening is controlled to be unnecessarily small, and the performance of the indoor heat exchanger is deteriorated.

  Moreover, in the control at the time of simultaneous cooling and heating of patent document 5, the control method of a compressor and an outdoor air blower was determined simultaneously with the suction pressure and discharge pressure of the compressor, and the evaporation temperature and the condensation temperature were controlled. However, in this method, the operation information of the utilization unit, for example, control that does not use the set temperature and the intake air temperature is used, it is difficult to estimate the air conditioning load of the utilization unit appropriately, and the operation frequency of the compressor is high. In some cases, control with low operating efficiency may occur due to an increase in the air volume of the outdoor fan or the like.

  The present invention has been made in order to solve the above-described problems, and improves multi-system air conditioning that improves driving efficiency and prevents uncooled and unheated units in the use unit and is excellent in comfort. An object is to provide an apparatus.

The air conditioner according to the present invention is
A plurality of usage units each equipped with a usage-side heat exchanger and an indoor decompression mechanism;
At least one heat source unit equipped with a compressor, a flow path switching device, a heat source side heat exchanger, and a heat source side blower;
A relay unit that is provided between the use unit and the heat source unit, and controls a flow of a refrigerant that flows into the use unit according to an operation state of the use unit;
In each operation of the use side heat exchanger of the use unit, an air conditioner capable of selecting cooling operation or heating operation,
Indoor decompression mechanism control means for controlling the indoor decompression mechanism provided in the utilization unit;
An air conditioning load performance amount calculating means for calculating the air conditioning load of each of the utilization units;
If the mixed cooling operation and heating operation to the operation of the plurality of utilization units, among the user units operating as the one main, the based on the air-conditioning load of the utilization unit air conditioning load is maximum Compressor control means for controlling the operating frequency of the compressor;
If the mixed cooling operation and heating operation to the operation of the plurality of utilization units, among the user units of the operation is the other slave, the based on the air-conditioning load of the utilization unit air conditioning load is maximum A heat source side blower control means for controlling the air volume of the heat source side blower,
The indoor decompression mechanism control means includes:
In the usage unit where the air conditioning load is maximum, the indoor pressure reducing mechanism of the usage unit is set so that the degree of superheat becomes a constant value in the cooling operation and the degree of supercooling becomes a constant value in the heating operation. Control to maximize the performance of the usage side heat exchanger of the usage unit ,
In the usage unit where the air conditioning load is not maximum, the indoor pressure reducing mechanism of the usage unit is controlled based on the air conditioning load .

  According to the air conditioner according to the present invention, by adopting the above-described configuration, the operation efficiency is improved, and in each use unit, it is possible to prevent uncooling and unwarming and improve comfort.

It is a refrigerant circuit diagram which shows the refrigerant circuit structure of the air conditioning apparatus of Embodiment 1 of this invention. It is the schematic which showed the process of the sensor information of Embodiment 1 of this invention, and a control apparatus object. It is the figure which showed the control method of the compressor 1 and the outdoor air blower 4 in Embodiment 1 of this invention. It is the figure which showed the time-dependent change of the evaporation temperature and the condensation temperature in Embodiment 1 of this invention. It is the figure which showed the control method of the indoor decompression mechanism 14 in Embodiment 1 of this invention. It is the figure which showed the average value calculation example of the intake air temperature in Embodiment 1 of this invention. It is the figure which showed the predicted value calculation example of the intake air temperature in Embodiment 1 of this invention. It is the figure which showed the example of an operation mode change of the utilization unit 303 in Embodiment 1 of this invention. It is the figure which showed gas refrigerant generation in the high voltage | pressure connection piping 6 in Embodiment 1 of this invention. It is an example of the operation state of each utilization unit at the time of the total cooling operation in Embodiment 1 of this invention. It is an example of the operation state of each utilization unit at the time of the cold main operation in Embodiment 1 of this invention. It is an example of the operation state of each utilization unit at the time of the full warm operation in Embodiment 1 of this invention. It is an example of the operation state of each utilization unit at the time of the warm main operation in Embodiment 1 of this invention. It is a refrigerant circuit diagram which shows the refrigerant circuit structure of the air conditioning apparatus of Embodiment 2 of this invention. It is a refrigerant circuit diagram which shows the refrigerant circuit structure of the air conditioning apparatus of Embodiment 3 of this invention.

Embodiment 1.
<Device configuration>
FIG. 1 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus 100 according to Embodiment 1 of the present invention. FIG. 2 is a schematic diagram showing the processing of various sensor information and the target of the control device. Based on FIG.1 and FIG.2, the structure and operation | movement of the air conditioning apparatus 100 are demonstrated.
This air conditioner 100 is a two-pipe multi-system air conditioner that can simultaneously process a cooling operation and a heating operation selected in each utilization unit by performing a vapor compression refrigeration cycle operation.

  In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one. Also, those with “a” after the code are in the usage unit 303a, those with “b” after the code are in the usage unit 303b, those with “c” after the code are in the usage unit 303c, and after the code. Those marked with “d” are arranged in the utilization unit 303d.

  The air conditioner 100 includes a heat source unit 301, a relay unit 302, and a usage unit 303 (a usage unit 303a, a usage unit 303b, a usage unit 303c, and a usage unit 303d). The heat source unit 301 and the relay unit 302 are connected by a high pressure connection pipe (second refrigerant pipe) 6 and a low pressure connection pipe (first refrigerant pipe) 24. Specifically, the outlet side of the first check valve 5 and the gas-liquid separator 7 are connected to the inlet of the fourth check valve 25 and the first solenoid valve 9 (first solenoid valve 9a) via the high-pressure connection pipe 6. The first electromagnetic valve 9b, the first electromagnetic valve 9c, and the first electromagnetic valve 9d) are connected via a low-pressure connection pipe 24.

  Further, the relay unit 302 and the use unit 303 include a first solenoid valve 9 (a first solenoid valve 9a, a first solenoid valve 9b, a first solenoid valve 9c, a first solenoid valve) provided in parallel to each use unit 303. Valve 9d) and second electromagnetic valve 10 (second electromagnetic valve 10a, second electromagnetic valve 10b, second electromagnetic valve 10c, second electromagnetic valve 10d) and indoor heat exchanger 12 (indoor heat exchanger 12a, indoor heat The second gas connection pipe 11 (second gas connection pipe 11a, second gas connection pipe 11b, second gas connection pipe 11c) in which the exchanger 12b, the indoor heat exchanger 12c, and the indoor heat exchanger 12d) are refrigerant pipes. 2nd check valve 16 (2nd check valve 16a, 2nd check valve 16b, 2nd check valve) which was connected via the 2nd gas connection piping 11d), and was provided in parallel with each utilization unit 303. 16c, second check valve 16d) and third check valve 17 A third check valve 17a, a third check valve 17b, a third check valve 17c, a third check valve 17d) and an indoor pressure reducing mechanism 14 (indoor pressure reducing mechanism 14a, indoor pressure reducing mechanism 14b, indoor pressure reducing mechanism 14c, The indoor pressure reducing mechanism 14d) is connected to the refrigerant through a second liquid connection pipe 15 (second liquid connection pipe 15a, second liquid connection pipe 15b, second liquid connection pipe 15c, second liquid connection pipe 15d). Has been.

  The first solenoid valve 9 and the second solenoid valve 10 select one of the indoor heat exchangers 12 (upper side in the drawing) of the utilization unit 303 as the high pressure connection pipe 6 via the low pressure connection pipe 24 or the gas-liquid separator 7. It functions as the 1st branch part to connect. Further, the second check valve 16 and the third check valve 17 are separated from each other through the first pressure reducing mechanism 20 when the other side (the lower side in the drawing) of the indoor heat exchanger 12 of the utilization unit 303 is a refrigerant inlet. When the other of the indoor heat exchangers 12 of the utilization unit 303 serves as a refrigerant outlet, it functions as a second branch portion connected to the downstream side of the first decompression mechanism 20.

  In addition, in Embodiment 1, although the case where four utilization units are connected to one heat source unit is shown as an example, the present invention is not limited to this, and each is illustrated above or below. May be provided. The refrigerant used in the air conditioner 100 is, for example, an HFC (hydrofluorocarbon) refrigerant such as R410A, R407C, or R404A, an HCFC (hydrochlorofluorocarbon) refrigerant such as R22 or R134a, or a natural material such as hydrocarbon or helium. There are refrigerants.

<Operation mode of heat source unit 301>
Here, the operation mode executed by the air conditioner 100 will be briefly described.
In the air conditioner 100, the operation mode of the heat source unit 301 is determined by the ratio of the cooling load and the heating load of the connected use unit 303. The air conditioner 100 is configured to execute the following four operation modes.

(A) An operation mode of the heat source unit 301 in the case where there is no heating load and all of the utilization units 303 execute the cooling operation (hereinafter referred to as a “cooling operation mode”).
(B) The operation mode of the heat source unit 301 when the cooling load is large in the simultaneous cooling and heating operation in which the use unit 303 performs both the cooling operation and the heating operation simultaneously (hereinafter referred to as the cooling main operation mode).
(C) An operation mode of the heat source unit 301 in the case where there is no cooling load and all of the utilization units 303 execute the heating operation (hereinafter, referred to as a full warming operation mode).
(D) The operation mode of the heat source unit 301 when the heating load is large in the simultaneous cooling and heating operation in which the use unit 303 performs both the cooling operation and the heating operation simultaneously (hereinafter referred to as a warm main operation mode).

<Usage unit 303>
The use unit 303 is installed in a place where conditioned air can be blown out to the air-conditioning target area (for example, by embedding in an indoor ceiling, hanging, or hanging on a wall surface). The utilization unit 303 is connected to the heat source unit 301 via the relay unit 302, the high-pressure connection pipe 6, and the low-pressure connection pipe 24, and constitutes a part of the refrigerant circuit.

  The utilization unit 303 includes an indoor refrigerant circuit that constitutes a part of the refrigerant circuit. This indoor refrigerant circuit includes an indoor heat exchanger 12 as a use side heat exchanger and an indoor decompression mechanism 14 connected in series to the indoor heat exchanger 12. Further, the use unit 303 includes an indoor blower 13 (indoor blower 13a, indoor blower 13b, indoor blower 13c) for supplying conditioned air after heat exchange with the refrigerant of the indoor heat exchanger 12 to an air-conditioning target area such as a room. , An indoor fan 13d) is provided.

  The indoor heat exchanger 12 can be constituted by, for example, a cross fin type fin-and-tube heat exchanger constituted by heat transfer tubes and a large number of fins. Moreover, you may comprise the indoor heat exchanger 12 with a microchannel heat exchanger, a shell and tube type heat exchanger, a heat pipe type heat exchanger, or a double pipe type heat exchanger. When the operation mode executed by the utilization unit 303 is the cooling operation mode, the indoor heat exchanger 12 functions as a refrigerant evaporator to cool the air in the air-conditioning target area, and in the heating operation mode, the refrigerant condenser. Functions to heat the air in the air-conditioning target area.

  The indoor blower 13 has a function of sucking room air into the use unit 303 and supplying the room air as conditioned air to the air-conditioning target area after exchanging heat with the room heat exchanger 12. That is, in the utilization unit 303, it is possible to exchange heat between the indoor air taken in by the indoor blower 13 and the refrigerant flowing through the indoor heat exchanger 12.

  The indoor blower 13 is configured to be capable of changing the flow rate of the conditioned air supplied to the indoor heat exchanger 12, and for example, a fan such as a centrifugal fan or a multiblade fan and a DC fan that drives the fan, for example. And a motor composed of a motor.

In addition, the utilization unit 303 is provided with various sensors shown below.
(1) An indoor gas temperature sensor 205 (indoor gas temperature sensor 205a, indoor gas temperature sensor 205b, indoor gas temperature sensor 205c, indoor gas temperature sensor) provided on the gas side of the indoor heat exchanger 12 and detecting the temperature of the gas refrigerant. 205d);
(2) An indoor suction temperature sensor 206 (indoor suction temperature sensor 206a, indoor suction temperature sensor 206b, indoor suction temperature) that is provided on the indoor air inlet side of the utilization unit 303 and detects the temperature of the indoor air flowing into the unit. Sensor 206c, indoor suction temperature sensor 206d);
(3) An indoor liquid temperature sensor 207 (indoor liquid temperature sensor 207a, indoor liquid temperature sensor 207b, indoor liquid temperature sensor 207c, indoor liquid temperature sensor provided on the liquid side of the indoor heat exchanger 12 to detect the temperature of the liquid refrigerant. 207d);

  The operations of the indoor pressure reducing mechanism 14 and the indoor blower 13 are controlled by the control unit 103 that functions as normal operation control means for performing normal operation including the cooling operation mode and the heating operation mode of the use unit 303 (see FIG. 2). .

<Heat source unit 301>
The heat source unit 301 is installed, for example, outdoors, and is connected to the utilization unit 303 via the high-pressure connection pipe 6 and the low-pressure connection pipe 24 and the relay unit 302, and a part of the refrigerant circuit in the air conditioner 100 is used. It is composed.

  In the heat source unit 301, two connection pipes (the first connection pipe 27 and the second connection) connected to the high pressure connection pipe 6 and the low pressure connection pipe 24 in order to make the flow direction of the refrigerant entering and leaving the relay unit 302 constant. A pipe 29) is provided.

  The heat source unit 301 includes an outdoor refrigerant circuit that constitutes a part of the refrigerant circuit. This outdoor refrigerant circuit includes a compressor 1 for compressing refrigerant, a four-way valve 2 for switching the direction of refrigerant flow, an outdoor heat exchanger 3 as a heat source side heat exchanger, and a refrigerant flow direction in one direction. Four check valves (first check valve 5, fourth check valve 25, fifth check valve 26, sixth check valve 28) that control the flow of refrigerant by allowing only the excess refrigerant, It is comprised with the accumulator 30 for storing. The heat source unit 301 is provided with an outdoor fan 4 for supplying air to the outdoor heat exchanger 3.

  The compressor 1 sucks refrigerant and compresses the refrigerant to a high temperature and high pressure state. The compressor 1 mounted on the air-conditioning apparatus according to Embodiment 1 has a variable operating capacity. For example, positive displacement compression driven by a motor (not shown) controlled by an inverter. It consists of a machine. In the first embodiment, the case where there is only one compressor 1 is shown as an example. However, the present invention is not limited to this, and two or more compressors 1 are arranged in parallel according to the number of connected units and the like. It may be connected to.

  The four-way valve 2 has a function as a flow path switching device that switches the direction of refrigerant flow according to the operation mode of the heat source unit 301. When the four-way valve 2 is in the all-cooling operation mode or the cold main operation mode, the outdoor side heat exchanger 3 functions as a condenser for refrigerant compressed in the compressor 1, The gas side of the heat exchanger 3 is connected, and the suction side of the compressor 1 is connected to the low pressure connection pipe 24 side via the fourth check valve 25 (see the solid line of the four-way valve 2). Further, the four-way valve 2 is connected to the discharge side of the compressor 1 and the fifth check valve 26 in order to make the outdoor heat exchanger 3 function as a refrigerant evaporator in the full warm operation mode or the warm main operation mode. Is connected to the high pressure connection pipe 6 side, and the suction side of the compressor 1 is connected to the gas side of the outdoor heat exchanger 3 (see the broken line of the four-way valve 2).

The first check valve 5 is provided between a connection part a between the high-pressure connection pipe 6 and the first connection pipe 27 and a connection part b between the high-pressure connection pipe 6 and the second connection pipe 29, and the heat source unit 301. The refrigerant is allowed to flow only in the direction from the relay unit 302 to the relay unit 302.
The fourth check valve 25 is provided between a connection portion c between the low pressure connection pipe 24 and the first connection pipe 27 and a connection portion d between the low pressure connection pipe 24 and the second connection pipe 29, and the relay unit 302. The refrigerant is allowed to flow only in the direction from the heat source unit 301 to the heat source unit 301.

The fifth check valve 26 is provided in the first connection pipe 27 and allows the refrigerant to flow only in the direction from the heat source unit 301 to the relay unit 302.
The sixth check valve 28 is provided in the second connection pipe 29 and allows the refrigerant to flow only in the direction from the relay unit 302 to the heat source unit 301.
By arranging the four check valves (5, 25, 26, 28) in this way, the refrigerant flow is allowed only in the direction from the heat source unit 301 to the relay unit 302 in the high-pressure connection pipe 6, and the low-pressure connection pipe 24 is provided. The refrigerant flow is allowed only in the direction from the relay unit 302 to the heat source unit 301, and the flow direction of the refrigerant when the four-way valve 2 is switched is determined.

  The outdoor heat exchanger 3 can be composed of, for example, a cross fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins. Moreover, you may comprise the outdoor heat exchanger 3 with a microchannel heat exchanger, a shell and tube type heat exchanger, a heat pipe type heat exchanger, or a double tube type heat exchanger. The outdoor heat exchanger 3 functions as a refrigerant condenser in the all-cooling operation mode and the cooling main operation mode to heat the refrigerant, and functions as a refrigerant evaporator in the all-warming operation mode and the warm main operation mode. It is to be cooled. The outdoor heat exchanger 3 has a gas side connected to the four-way valve 2 and a liquid side connected to the first check valve 5 and the sixth check valve 28.

  The outdoor blower 4 has a function of sucking outdoor air into the heat source unit 301, exchanging the outdoor air with the outdoor heat exchanger 3, and then discharging the outdoor air to the outside. That is, in the heat source unit 301, heat exchange can be performed between the outdoor air taken in by the outdoor fan 4 and the refrigerant flowing through the outdoor heat exchanger 3.

  The outdoor blower 4 can vary the flow rate of air supplied to the outdoor heat exchanger 3, and includes a fan such as a propeller fan and a motor that drives the fan, such as a DC fan motor. ing.

  The accumulator 30 stores a liquid refrigerant and prevents liquid back to the compressor 1 when an abnormality occurs in the air conditioner 100 or during a transient response of an operation state associated with a change in operation control. 1 is connected to the suction side.

In addition, the heat source unit 301 is provided with various sensors shown below.
(1) A discharge pressure sensor 201 (high pressure detection device) provided on the discharge side of the compressor 1 for detecting the discharge pressure;
(2) An outdoor gas temperature sensor 202 that is provided on the gas side of the outdoor heat exchanger 3 and detects the temperature of the gas refrigerant;
(3) An outdoor air temperature sensor 203 that is provided on the outdoor air inlet side of the heat source unit 301 and detects the temperature of the outdoor air flowing into the unit;
(4) An outdoor liquid temperature sensor 204 provided on the liquid side of the outdoor heat exchanger 3 for detecting the liquid refrigerant temperature;
(5) A suction pressure sensor 213 (low pressure detection device) provided on the suction side of the compressor 1 for detecting the suction pressure;

  The operation of the compressor 1, the four-way valve 2 and the outdoor blower 4 is a control functioning as a normal operation control means for performing a normal operation including a full cooling operation mode, a cooling main operation mode, a full warm operation mode, and a warm main operation mode. Controlled by the unit 103.

<Relay unit 302>
The relay unit 302 is installed indoors, for example, connected to the heat source unit 301 via the low pressure connection pipe 24 and the high pressure connection pipe 6, and connected to the utilization unit 303 via the second gas connection pipe 11 and the second liquid connection pipe 15. It is connected and constitutes a part of the refrigerant circuit in the air conditioner 100. The relay unit 302 is interposed between the heat source unit 301 and the usage unit 303 and has a function of controlling the flow of the refrigerant according to the operation required for each usage unit 303.

  The relay unit 302 includes a relay refrigerant circuit that constitutes a part of the refrigerant circuit. This relay refrigerant circuit includes a gas-liquid separator 7 for separating liquid refrigerant and gas refrigerant, a first electromagnetic valve 9 and a second electromagnetic valve 10 for switching operation of the utilization unit 303, and a flow direction of the refrigerant. To control the second check valve 16 and the third check valve 17 for determination, the first heat exchange unit 19 and the second heat exchange unit 21 for heat exchange of the refrigerant, and the distribution flow rate of the refrigerant The first decompression mechanism 20 and the second decompression mechanism 22 are configured.

  The gas-liquid separator 7 has a function of separating the refrigerant flowing in via the high-pressure connection pipe 6 into a gas refrigerant and a liquid refrigerant. The gas-liquid separator 7 is connected to the heat source unit 301 via the high-pressure connection pipe 6, is connected to the second electromagnetic valve 10 via the first gas connection pipe 8, and is connected to the first via the first liquid connection pipe 18. The heat exchange unit 19 is connected.

One of the first solenoid valve 9 and the second solenoid valve 10 is selectively controlled to open or close in the operation required for the connected use unit 303, so that the first solenoid valve 9 and the second solenoid valve 10 can be operated according to the operation of the use unit 303. It has a function of controlling the flow of the refrigerant.
The first electromagnetic valve 9 (9a to 9d) is constituted by, for example, a two-way valve or the like, and is provided in the second gas connection pipe 11 (11a to 11d) branched and connected to the low pressure connection pipe 24.
The second electromagnetic valve 10 (10a to 10d) is constituted by, for example, a two-way valve or the like, and is provided in a second gas connection pipe 11 (11a to 11d) that branches and connects to the high pressure connection pipe 6.

The second check valve 16 and the third check valve 17 have a function of circulating the refrigerant to one side according to the operation required for the connected use unit 303.
The second check valve 16 (16a to 16d) is provided in the second liquid connection pipe 15 (15a to 15d) that is branched and connected to the first liquid connection pipe 18.
The third check valve 17 (17a to 17d) is provided in the second liquid connection pipe 15 (15a to 15d) branched and connected to the first liquid connection pipe 18.

The first heat exchange unit 19 connects the refrigerant that is conducted through the first liquid connection pipe 18 between the gas-liquid separator 7 and the first pressure reduction mechanism 20, the second heat exchange unit 21, and the low pressure connection pipe 24. Heat exchange is performed with the refrigerant that is conducted through the connected bypass connection pipe 23.
The second heat exchange unit 21 includes a refrigerant that is conducted through the bypass connection pipe 23 between the second pressure reduction mechanism 22 and the first heat exchange unit 19, and the first pressure reduction mechanism 20 and the third check valve 17. Heat exchange is performed between the refrigerant and the first liquid connection pipe 18 in between.
The bypass connection pipe 23 has one end connected to the high-pressure side outlet of the second heat exchange unit 21 and the other end connected to the low-pressure connection pipe 24.

  The first pressure reduction mechanism 20 is provided in the first liquid connection pipe 18 between the first heat exchange part 19 and the branch part that merges with the refrigerant that has passed through the second check valve 16, and has a function of reducing the pressure of the refrigerant. have. The first pressure reducing mechanism 20 may be configured by a variable flow rate control unit such as a precise flow rate control unit using an electronic expansion valve or an inexpensive refrigerant flow rate control unit such as a capillary tube.

  The second decompression mechanism 22 is connected to the upstream side of the second heat exchange unit 21 in the bypass connection pipe 23, and has a function of decompressing and expanding the refrigerant. The second decompression mechanism 22 may be configured with a controllable flow rate control means such as a precise flow rate control means such as an electronic expansion valve or an inexpensive refrigerant flow rate control means such as a capillary tube.

Further, the relay unit 302 is provided with various sensors shown below.
(1) A high-pressure sensor 208 provided downstream of the first heat exchange unit 19 on the high-pressure side and detects the pressure on the high-pressure side;
(2) An intermediate pressure sensor 209 that is provided downstream of the first pressure reducing mechanism 20 and detects the pressure of the intermediate pressure;
(3) An intermediate pressure liquid temperature sensor 210 that is provided downstream of the second heat exchange unit 21 on the high pressure side and detects the liquid refrigerant temperature on the intermediate pressure side;
(4) a low-pressure saturation temperature sensor 211 that is provided on the low-pressure upstream side of the second heat exchange unit 21 and detects a saturation temperature on the low-pressure side;
(5) a low-pressure gas temperature sensor 212 provided on the low-pressure downstream side of the first heat exchange unit 19 and detecting the gas refrigerant temperature on the low-pressure side;

  As shown in FIG. 2, various quantities detected by various temperature sensors and pressure sensors are input to the measurement unit 101 and processed by the calculation unit 102. And the air conditioning apparatus 100 is based on the processing result of the calculating part 102, and the control part 103 makes the compressor 1, the four-way valve 2, the outdoor air blower 4, the indoor air blower 13, the indoor pressure reduction mechanism 14, the 1st pressure reduction mechanism 20, The second pressure reducing mechanism 22, the first electromagnetic valve 9, and the second electromagnetic valve 10 are controlled. That is, the operation of the air conditioner 100 is centrally controlled by the measurement unit 101, the calculation unit 102, and the control unit 103. These may be constituted by a microcomputer or the like.

Specifically, the control unit 103 switches the driving frequency of the compressor 1, the switching of the four-way valve 2, and the rotation of the outdoor blower 4 based on an instruction and information detected by various sensors via an input / calculated remote controller or the like. Number (including ON / OFF), rotation speed of the indoor blower 13 (including ON / OFF), opening of the indoor decompression mechanism 14, opening of the first decompression mechanism 20, opening of the second decompression mechanism 22, and first electromagnetic Each operation mode is executed by controlling the opening and closing of the valve 9 and the opening and closing of the second electromagnetic valve 10, respectively. In addition, the measurement part 101, the calculating part 102, and the control part 103 may be provided integrally, and may be provided separately. The measurement unit 101, the calculation unit 102, and the control unit 103 may be provided in any unit. Furthermore, the measurement unit 101, the calculation unit 102, and the control unit 103 may be provided for each unit.
The calculation unit 102 corresponds to an air load related amount calculation unit and a saturation temperature target calculation unit of the present invention, and the control unit 103 corresponds to a compressor control unit and a heat source side blower control unit.

  The air conditioner 100 includes each device mounted on the heat source unit 301, the relay unit 302 and the usage unit 303a, the usage unit 303b, the usage unit 303c, and the usage unit 303d in accordance with each operation load required for the usage unit 303. And the all-cooling operation mode, the cooling main operation mode, the all-warming operation mode, or the warm main operation mode is executed.

<Control method of compressor 1 and outdoor blower 4>
The compressor 1 and the outdoor fan 4 are controlled by the total air conditioning load of the usage unit 303.
FIG. 3 shows a method for controlling the compressor 1 and the outdoor blower 4 in each operation mode.
The total air conditioning load of the unit used for cooling operation is compared with the total air conditioning load of the unit used for heating operation, and the air conditioning capacity required for the larger total air conditioning load (the operation corresponds to the main operation of the present invention) And the operating frequency of the compressor 1 is determined. Further, the air flow capacity of the outdoor blower 4 is determined by grasping the air conditioning capability corresponding to the exhaust heat recovery amount with the smaller total air conditioning load (the operation corresponds to the operation according to the present invention). In the total cooling operation and the cooling main operation, the total cooling load is larger than the total heating load. Therefore, the compressor 1 is set to evaporating temperature control, and the outdoor fan 4 is set to condensing temperature control. On the contrary, since the total heating load is larger than the total cooling load in the full warm operation and the warm main operation, the compressor 1 is set as the condensation temperature control and the outdoor fan 4 is set as the evaporation temperature control.

Further, the magnitude of the air conditioning load is determined by the air conditioning load related quantity.
In the first embodiment, the temperature difference between the intake air temperature T _a [° C.] and the indoor air set temperature T _set [° C.] is used as the air conditioning load related quantity, and control is performed assuming that the air conditioning load increases as the difference temperature increases. . Note that the temperature difference ΔT _c of the usage unit 303 during the cooling operation is ΔT _c = T _a −T _set , and the temperature difference ΔT _h of the usage unit 303 during the heating operation is ΔT _h = T _set −T _a .
Further, since the evaporating temperature and the condensing temperature are fixed state quantities with respect to each usage unit 303, it is not possible to obtain the air conditioning capability corresponding to the air conditioning load in all the usage units only by changing the condensing temperature and the evaporating temperature. For this reason, in the first embodiment, the condensing temperature and the evaporating temperature are determined for the utilization unit 303 having the maximum air conditioning load among the utilization units 303 to control the air conditioning capacity.

In the evaporation temperature control, the evaporation temperature target T _em is calculated according to Equation 1.

Here, T _e [° C.] is the evaporation temperature, T _{a, maxc} [° C.] is the intake air temperature of the cooling operation using unit having the maximum differential temperature among the cooling operation using units, and T _{set, maxc} [° C.] is the cooling operation. This is the set temperature of the cooling operation utilization unit having the maximum differential temperature among the utilization units. The evaporation temperature T _e, for example, a temperature detected by the indoor liquid temperature sensor 207. The evaporation temperature _Te is not limited to this, and the saturation temperature may be calculated from the pressure detected by the suction pressure sensor 213 and the temperature may be applied.

The evaporation temperature T _e in accordance with the cooling load by controlling by a formula 1, the maximum cooling operation utilizing unit 303 differential temperature, i.e., to control the cooling capacity of the utilization unit 303 of the maximum cooling load. Inlet air temperature T _{a, maxc} set temperature T _{The set,} is higher than _maxc the evaporation temperature target T _em is lower than the evaporation temperature T _e, increases the cooling capacity. When the compressor 1 controls the evaporation temperature, the operating frequency increases, and when the outdoor blower 4 operates, the air volume decreases. Conversely, the suction air temperature T _{a, maxc} set temperature T _{The set,} is lower than _maxc the evaporation temperature target T _em is higher than T _e, reducing the cooling capacity. When the compressor 1 controls the evaporation temperature, the operating frequency decreases, and when the outdoor blower 4 is operating, the air volume increases.

Further, in the condensing temperature control, the condensing temperature target T _cm is calculated by Equation 2.

Here, T _c [° C.] is the condensation temperature, T _{a, max} h [° C.] is the intake air temperature of the heating operation using unit having the maximum differential temperature among the heating operation using units, and T _{set, max} h [° C.] is the heating. This is the set temperature of the heating operation utilization unit having the maximum differential temperature among the operation utilization units. As the condensation temperature T _c , for example, the saturation temperature may be obtained from the detected pressure of the high pressure sensor 208 and the temperature may be applied. The condensation temperature T _c is not limited to this, and the saturation temperature may be calculated from the pressure detected by the discharge pressure sensor 201 and the temperature may be applied.

By controlling the condensing temperature _Tc according to the heating load according to Equation 2, the heating capacity of the heating operation utilization unit 303 having the maximum differential temperature, that is, the utilization unit 303 having the maximum heating load is controlled. Inlet air temperature T _{a, maxh} set temperature T _{The set,} is lower than _maxh is the condensing temperature target T _cm is higher than the condensation temperature T _c, increasing the heating capacity. When the compressor controls the condensation temperature, the operating frequency increases, and when the outdoor fan 4 operates, the air volume decreases. On the contrary, when the intake air temperatures T _a and _maxh are higher than the set temperatures T _{set and maxh} , the condensation temperature target T _cm becomes lower than T _c and the heating capacity is reduced. When the compressor controls the condensation temperature, the operating frequency decreases, and when the outdoor fan 4 operates, the air volume increases.

  In addition, since there is no heating load in the cooling operation, there is no exhaust heat recovery amount. Further, since there is no cooling load in the full warm operation, there is no exhaust heat recovery amount. Therefore, in these operations, the operation efficiency is improved by maximizing the performance of the outdoor heat exchanger 3 by maximizing the air volume of the outdoor fan 4.

As described above, by controlling each by the compressor 1 and the outdoor blower 4 the control unit 103, the evaporation temperature T _e and the condensation temperature T _c is controlled, evaporation temperature T _e according to the maximum air-conditioning load of the utilization unit 303 And the condensation temperature T _c is determined. FIG. 4 shows changes with time of the evaporation temperature _Te and the condensation temperature _Tc at this time. Following the air conditioning load, the evaporating temperature _Te is increased and the condensing temperature _Tc is decreased. That is, it becomes possible to reduce the compression ratio of the compressor, and therefore an efficient operating state is achieved.

  According to the first embodiment, since the compressor 1 can be controlled in accordance with the load, the operation frequency does not increase excessively. Since the outdoor fan 4 is controlled by the air conditioning load, the amount of heat in the outdoor heat exchanger 3 is controlled corresponding to the air conditioning load. Therefore, it becomes an efficient driving | running state. If the air volume of the outdoor blower 4 is not properly controlled, the following state is brought about and the operating efficiency is deteriorated. When the outdoor fan 4 has a large amount of air, the amount of heat in the outdoor heat exchanger 3 increases, so that the amount of exhaust heat recovered by the utilization unit 303 is reduced, and it becomes uncooled and unwarmed. Or, switching between the cold main operation and the warm main operation occurs, and the operation efficiency becomes poor. On the other hand, when the air volume of the outdoor fan 4 is small, the amount of heat in the outdoor heat exchanger 3 decreases, so the amount of exhaust heat recovered in the utilization unit 303 increases excessively, and the performance of the indoor heat exchanger 12 is reduced. It becomes necessary to make it smaller, the opening degree of the indoor pressure reducing mechanism 14 becomes smaller, and the operation efficiency becomes poor. According to the first embodiment, since these previous states can be avoided, the driving efficiency is improved.

<Control method of indoor decompression mechanism 14>
In the use unit 303 where the temperature difference is not maximum, that is, not the maximum air conditioning load, the indoor decompression mechanism 14 controls the air conditioning capacity.
FIG. 5 shows a control method of the indoor decompression mechanism 14. In both the cooling and heating operation units, when the differential temperature is 0 ° C or higher, the air conditioning capacity is increased to increase the differential temperature to 0 ° C, and when the differential temperature is 0 ° C or lower, the air conditioning In order to reduce the capacity and make the temperature difference 0 ° C., the opening degree is decreased. The indoor decompression mechanism 14 is controlled according to the temperature difference of the utilization unit 303, that is, according to the air conditioning load.

  However, in the case of a utilization unit for cooling operation, if the degree of superheat on the gas side of the indoor heat exchanger 12 is less than a threshold value, for example, less than 2 ° C. due to an increase in the opening of the indoor decompression mechanism 14, the compressor 1 In order to protect the liquid back, the opening degree of the indoor pressure reducing mechanism 14 is made small so that the degree of superheat becomes a threshold value. Here, the degree of superheat on the gas side of the indoor heat exchanger 12 is first calculated by subtracting the temperature detected by the indoor liquid temperature sensor 207 from the temperature detected by the indoor gas temperature sensor 205. In the case of a heating operation unit, when the degree of supercooling on the liquid side of the indoor heat exchanger 12 is less than a threshold value, for example, less than 10 ° C., by increasing the opening of the indoor decompression mechanism 14, the indoor heat exchanger In order to maximize the performance of 12, the opening degree of the indoor decompression mechanism 14 is reduced. Here, the degree of supercooling on the liquid side of the indoor heat exchanger 12 is calculated by first calculating the condensation temperature from the pressure detected by the high pressure sensor 208 and subtracting the temperature detected by the indoor liquid temperature sensor 205d. .

  The air conditioning capacity of the utilization unit 303 with the maximum air conditioning load is controlled by the compressor 1 or the outdoor fan 4. Therefore, in the utilization unit 303 for cooling operation with the maximum air conditioning load, the opening degree of the indoor decompression mechanism 14 is increased so that the degree of superheat on the gas side of the indoor heat exchanger 12 becomes 2 ° C. By controlling in this way, the performance of the indoor heat exchanger 12 can be maximized to the extent that the compressor 1 does not perform liquid back, and it is not necessary to operate the compressor 1 redundantly. improves. Moreover, in the utilization unit 303 for heating operation with the maximum air conditioning load, the opening degree of the indoor decompression mechanism 14 is increased so that the degree of supercooling on the liquid side of the indoor heat exchanger 12 is 10 ° C. By controlling in this way, the performance of the indoor heat exchanger 12 can be maximized, and the operation efficiency is improved. As described above, the indoor pressure reducing mechanism 14 is controlled by the control unit 103.

<Advantages of Embodiment 1>
Fixed with respect to the set temperature T _set and the suction air temperature T _a compressor from the difference in temperature of 1 and an outdoor fan 4 each utilization unit 303 by controlling each of the utilization units 303 of the maximum air-conditioning load in the first embodiment The evaporating temperature _Te and the condensing temperature _Tc , which are various state quantities, are controlled to control the air conditioning capability of the utilization unit 303 of the maximum air conditioning load. Air conditioning capacity of the utilization unit 303 is not the maximum air conditioning load by setting the temperature T _set and the suction air temperature T _a, and controls to adjust the performance of the indoor heat exchanger 12 by reducing the opening degree of the indoor pressure reducing mechanism 14.
As described above, the compressor 1, by controlling the outdoor blower 4 and the indoor pressure reducing mechanism 14, respectively, it is possible to control corresponding to the air conditioning load from the set temperature T _set and the suction air temperature T _a, the air conditioning load Accordingly, the operating frequency of the compressor 1 can be minimized, and the amount of exhaust heat in the outdoor heat exchanger 3 can be controlled without excess or deficiency by controlling the air volume of the outdoor fan 4 according to the air conditioning load. Further, since the performance of the indoor heat exchanger 12 can be made as large as possible by controlling the opening degree of the indoor decompression mechanism 14, the operation is controlled with high operating efficiency.

  In addition, the air-conditioning capability corresponding to the air-conditioning load can be obtained in all the use units 303, and air-conditioning excellent in comfort without causing uncooling and non-warming is possible.

<Other controls>
Inlet air temperature T _a for use in control of the compressor 1, the outdoor blower 4 and the indoor pressure reducing mechanism 14, in addition to the use of only the current detection value of the indoor suction temperature sensor 206, the average value and historical past detection value A predicted value calculated from the detected value may be used.

  As shown in FIG. 6, for example, an average value may be calculated from detection values of the past five points, and the average value may be used as a current value for control. By using this method, it becomes possible to suppress the measurement variation of the sensor, so that the control operation is stabilized. Therefore, useless operation of each device can be suppressed, and deterioration of efficiency can be suppressed.

  Further, as shown in FIG. 7, for example, the next detected value is calculated as a predicted value linearly from the detected values of the past two points (in the figure, data 1 is 26.9 ° C. and data 2 is 26.2 ° C. The next data 3 is assumed to be 25.5 ° C. assuming that the difference between the data 1 and the data 2 is 0.7 ° C.), and the predicted value is used as the current value for the control. May be. By using this method, since the control operation of each device is predicted, hunting of each device can be prevented and the control operation is stabilized. Therefore, useless operation can be suppressed, and deterioration of efficiency can be suppressed.

In addition, as shown in FIG. 8, when the operation mode of the usage unit 303 (for example, the usage unit 303 a) is a cooling operation and the operation is stopped to the cooling operation (Case 1), the cooling load increases. Therefore, the operating frequency of the compressor 1 is increased. Further, in the cooling main operation, when the operation is stopped from the cooling operation (case 2), the cooling load increases, so the operating frequency of the compressor 1 is increased. Further, when the cooling operation is changed from the heating operation (case 3), the cooling air-conditioning load increases, so the operating frequency of the compressor 1 is increased, and the heating load is decreased, so the air volume of the outdoor fan 4 is increased. Let In the full warm operation, when the operation is stopped and the heating operation is performed (case 4), the heating load increases, so the operation frequency of the compressor 1 is increased. In the warm main operation, when the operation is stopped and the heating operation is performed (case 5), since the heating load increases, the operation frequency of the compressor 1 is increased. When the cooling operation is switched to the heating operation (case 6), the heating load increases, so the operating frequency of the compressor 1 is increased, and the cooling load is decreased, so the air volume of the outdoor fan 4 is increased. .
As described above, since the change of the air conditioning load can be predicted by the change of the operation mode of the usage unit 303, the hunting of each device can be performed by controlling the compressor 1 and the outdoor blower 4 correspondingly. Can be prevented, and the control operation is stabilized. Therefore, it is possible to suppress useless operation of each device and suppress deterioration of efficiency.

In the case of the all-cooling operation, as shown in FIG. 9, a high-pressure liquid refrigerant flows through the high-pressure connection pipe 6, but pressure loss due to friction and the heat source unit 301 are installed below the relay unit 302. In such a case, gas refrigerant is generated due to the pressure drop caused by the liquid head. This gas refrigerant causes refrigerant noise and hunting in the indoor decompression mechanism 14.
Therefore, in the case of the all-cooling operation, the gas refrigerant in the high-pressure connection pipe 6 is controlled by controlling the air volume of the outdoor blower 4 so that the degree of supercooling on the liquid side of the outdoor heat exchanger 3 becomes a certain temperature or more. Since it is possible to prevent the generation of the refrigerant and to suppress the noise of the refrigerant, the user is not uncomfortable and the comfort is improved. Moreover, hunting can be prevented and the control operation is stabilized. Therefore, it is possible to suppress useless operation of each device and suppress deterioration of efficiency.
The degree of supercooling on the liquid side of the outdoor heat exchanger 3 is calculated, for example, by subtracting the temperature detected by the outdoor liquid temperature sensor 204 from the temperature calculated from the pressure detected by the discharge pressure sensor 201. Also good.

  As described above, the two-tube multi-system air conditioner 100 according to Embodiment 1 can provide an air conditioner that is excellent in comfort and efficient. From the next section, the specific refrigerant flow and the control operation of each device in each operation mode will be described.

<Cooling operation mode>
In the all-cooling operation mode, the state where the four-way valve 2 is indicated by a solid line, that is, the discharge side of the compressor 1 is connected to the gas side of the outdoor heat exchanger 3, and the suction side of the compressor 1 is the fourth check valve 25. It is in the state connected to the low voltage | pressure connection piping 24 via. Further, all the utilization units 303 are in the cooling operation mode, and the first electromagnetic valve 9 is controlled to be opened and the second electromagnetic valve 10 is controlled to be closed.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant is sent to the outdoor heat exchanger 3 via the four-way valve 2, exchanges heat with the outdoor air supplied by the outdoor blower 4, and is condensed to become a high-pressure liquid refrigerant. .

  This high-pressure liquid refrigerant passes through the high-pressure connection pipe 6 via the first check valve 5 and is sent to the gas-liquid separator 7 of the relay unit 302. Then, it flows into the high pressure side of the first heat exchange unit 19. The refrigerant flowing into the first heat exchange unit 19 releases heat to the refrigerant flowing on the low pressure side of the first heat exchange unit 19. This refrigerant flows out from the high pressure side of the first heat exchange unit 19 and flows into the first pressure reducing mechanism 20 whose opening degree is fully open. The refrigerant that has passed through the first pressure reduction mechanism 20 then flows into the high pressure side of the second heat exchange unit 21 and releases heat to the refrigerant that flows on the low pressure side of the second heat exchange unit 21. Thereafter, the refrigerant is distributed so as to flow through the second pressure reducing mechanism 22 and the third check valve 17.

  The refrigerant flowing into the second decompression mechanism 22 is depressurized to become a low-pressure gas-liquid two-phase state, flows into the low-pressure side of the second heat exchange unit 21, and is heated by the refrigerant flowing through the high-pressure side of the second heat exchange unit 21. Is done. Thereafter, the refrigerant flows out from the low pressure side of the second heat exchange unit 21, flows into the first heat exchange unit 19, and is heated by the refrigerant flowing through the high pressure side of the first heat exchange unit 19. Thereafter, the refrigerant flows into the low pressure connection pipe 24 through the bypass connection pipe 23.

  The second decompression mechanism 22 is controlled by the control unit 103 so that the degree of superheat on the low pressure side downstream of the first heat exchange unit 19 becomes a predetermined value. The degree of superheat on the low pressure side downstream of the first heat exchange unit 19 is obtained by subtracting the temperature detected by the low pressure saturation temperature sensor 211 from the temperature detected by the low pressure gas temperature sensor 212.

  Since the second pressure reducing mechanism 22 controls the flow rate of the refrigerant flowing through the second pressure reducing mechanism 22 so that the degree of superheat of the refrigerant at the low pressure side downstream of the first heat exchanging portion 19 becomes a predetermined value, the first heat exchange The low-pressure gas refrigerant evaporated on the low-pressure downstream side of the section 19 has a predetermined degree of superheat. As described above, the second decompression mechanism 22 is controlled so that the refrigerant having a flow rate according to the cooling load required in the air-conditioned space flows to the use unit 303a and the use unit 303b.

  On the other hand, the refrigerant that has flowed into the third check valve 17 flows into the utilization unit 303 via the second liquid connection pipe 15. Thereafter, the pressure is reduced by the indoor pressure reducing mechanism 14, and a low-pressure gas-liquid two-phase state is obtained and flows into the indoor heat exchanger 12. And it heat-exchanges with the indoor air supplied by the indoor air blower 13, evaporates, and turns into a low-pressure gas refrigerant.

  The indoor decompression mechanism 14 controls the flow rate of the refrigerant flowing through the indoor heat exchanger 12, and the indoor heat exchanger 12 has a flow rate according to the cooling load required in the air-conditioned space where the use unit 303 is installed. Refrigerant is flowing.

  The low-pressure gas refrigerant that has cooled the indoor air by the indoor heat exchanger 12 flows out from the indoor heat exchanger 12, flows through the second gas connection pipe 11, and flows out from the utilization unit 303. This refrigerant flows into the low pressure connection pipe 24 via the first electromagnetic valve 9, and flows into the second pressure reducing mechanism 22 and merges with the refrigerant that has flowed through the bypass connection pipe 23.

  The merged refrigerant flows into the heat source unit 301, passes through the fourth check valve 25, passes through the four-way valve 2 and the accumulator 30, and is sucked into the compressor 1 again.

In the all-cooling operation, all the use units 303 are in the cooling operation, and there is no heating load and only the cooling load. Therefore, the evaporating temperature _Te is controlled by the operating frequency of the compressor 1 to control the cooling capacity of the cooling operation utilization unit 303 having the maximum differential temperature. Moreover, the performance of the outdoor heat exchanger 3 is maximized by maximizing the air volume of the outdoor fan 4. In the use unit 303 in which the differential temperature is not maximum, the cooling capacity is controlled by controlling the opening of the indoor decompression mechanism 14 according to the differential temperature. Note that the opening degree of the indoor pressure reducing mechanism 14 of the cooling operation utilization unit 303 having the maximum temperature difference is controlled so as to prevent the liquid back from being generated in the compressor 1.

  For example, in the operation state of FIG. 10, the differential temperature of the utilization unit 303 c is a maximum of 5 ° C., so the cooling capacity of the utilization unit 303 c is controlled by the compressor 1. The indoor decompression mechanism 14 controls the cooling capacity of the other usage units 303.

<Cold main operation mode>
The cooling main operation mode described here is that the use unit 303a and the use unit 303b are in the cooling operation mode, and the use unit 303c and the use unit 303d are in the heating operation mode, but the cooling operation load is larger than the heating operation load. It is a driving operation mode.
In this cooling main operation mode, the cooling operation corresponds to one main operation of the present invention, and the heating operation corresponds to the other sub operation of the present invention.
In this cold main operation mode, the four-way valve 2 is controlled in the same manner as in the all-cooling operation mode. Further, the first electromagnetic valve 9a and the first electromagnetic valve 9b are opened, the first electromagnetic valve 9c and the first electromagnetic valve 9d are closed, the second electromagnetic valve 10a and the second electromagnetic valve 10b are closed, the second electromagnetic valve 10c and The second electromagnetic valve 10d is controlled to open.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant is sent to the outdoor heat exchanger 3 via the four-way valve 2 and is condensed by exchanging heat with the outdoor air supplied by the outdoor blower 4. Become.

  The high-pressure liquid refrigerant passes through the high-pressure connection pipe 6 via the first check valve 5, flows into the relay unit 302, and is sent to the gas-liquid separator 7. The refrigerant that has flowed into the gas-liquid separator 7 is separated into a gas refrigerant and a liquid refrigerant. The gas refrigerant passes through the first gas connection pipe 8 and flows into the second electromagnetic valve 10c and the second electromagnetic valve 10d. On the other hand, the liquid refrigerant flows into the high-pressure side of the first heat exchange unit 19 through the first liquid connection pipe 18.

  The gas refrigerant that has flowed into the second electromagnetic valve 10c and the second electromagnetic valve 10d passes through the second gas connection pipe 11c and the second gas connection pipe 11d, and then the use unit 303c, the indoor heat exchanger 12c of the use unit 303d, The heat exchanger 12d exchanges heat with the indoor air supplied by the indoor fan 13c and the indoor fan 13d to condense into a high-pressure liquid refrigerant. Thereafter, the high-pressure liquid refrigerant that has heated the room air is depressurized by the indoor pressure-reducing mechanism 14c and the indoor pressure-reducing mechanism 14d, and becomes an intermediate-pressure gas-liquid two-phase or liquid-phase refrigerant.

  The indoor decompression mechanism 14c and the indoor decompression mechanism 14d control the flow rate of the refrigerant flowing through the indoor heat exchanger 12c and the indoor heat exchanger 12d. The indoor heat exchanger 12c and the indoor heat exchanger 12d include a use unit 303c. The refrigerant having a flow rate according to the heating load required in the air-conditioned space in which the use unit 303d is installed flows. Thereafter, it flows out of the indoor pressure reducing mechanism 14c and the indoor pressure reducing mechanism 14d, flows out of the usage unit 303c and the usage unit 303d, passes through the second liquid connection pipe 15c and the second liquid connection pipe 15d, and then passes through the second check valve 16c. Then, it merges with the refrigerant that has passed through the first pressure reducing mechanism 20 via the second check valve 16d.

  On the other hand, the liquid refrigerant separated by the gas-liquid separator 7 and flowing into the high pressure side of the first heat exchange unit 19 through the first liquid connection pipe 18 is heated to the refrigerant flowing on the low pressure side of the first heat exchange unit 19. And is decompressed by the first decompression mechanism 20, and becomes an intermediate-pressure gas-liquid two-phase or liquid-phase refrigerant.

  Here, the first pressure reducing mechanism 20 is controlled by the control unit 103 so that the opening is such that the differential pressure between the high pressure and the intermediate pressure becomes a predetermined value. The differential pressure between the high pressure and the intermediate pressure is obtained by subtracting the pressure detected by the intermediate pressure sensor 209 from the pressure detected by the high pressure sensor 208.

  Since the first pressure reducing mechanism 20 controls the flow rate of the refrigerant flowing through the first pressure reducing mechanism 20 so that the differential pressure between the high pressure side and the intermediate pressure side becomes a predetermined value, the differential pressure between the high pressure side and the intermediate pressure side Is in a state having a predetermined value. Thus, the 1st decompression mechanism 20 is controlled so that the refrigerant | coolant of the flow volume according to the heating operation load requested | required in air-conditioning space flows into the utilization unit 303c and the utilization unit 303d.

  The refrigerant that has passed through the first pressure reducing mechanism 20 flows out of the use unit 303c and the use unit 303d and merges with the refrigerant that has passed through the second check valve 16c and the second check valve 16d, and the second heat exchange unit 21. Flows into the high-pressure side.

  Heat is released to the refrigerant flowing on the low pressure side of the second heat exchange unit 21 on the high pressure side of the second heat exchange unit 21, and then the second decompression mechanism 22, the third check valve 17a, and the third check valve 17b. And is distributed to the refrigerant flowing through.

  The refrigerant flowing into the second decompression mechanism 22 is decompressed, becomes a low-pressure gas-liquid two-phase state, and flows into the low-pressure side of the second heat exchange unit 21. The refrigerant flowing into the low pressure side of the second heat exchange unit 21 is heated by the refrigerant flowing through the high pressure side of the second heat exchange unit 21. Thereafter, the refrigerant flows into the low pressure side of the first heat exchange unit 19, is heated by the refrigerant flowing on the high pressure side in the first heat exchange unit 19, and flows into the low pressure connection pipe 24.

  The second decompression mechanism 22 is controlled by the control unit 103 so that the degree of superheat on the low pressure side downstream of the first heat exchange unit 19 becomes a predetermined value.

  On the other hand, the refrigerant that has flowed into the third check valve 17a and the third check valve 17b flows into the use unit 303a and the use unit 303b via the second liquid connection pipe 15a and the second liquid connection pipe 15b. The refrigerant flowing into the usage unit 303a and the usage unit 303b is decompressed by the indoor decompression mechanism 14a and the indoor decompression mechanism 14b, becomes a low-pressure gas-liquid two-phase state, and flows into the indoor heat exchanger 12a and the indoor heat exchanger 12b. In the indoor heat exchanger 12a and the indoor heat exchanger 12b, heat is exchanged with the indoor air supplied by the indoor blower 13a and the indoor blower 13b to evaporate into a low-pressure gas refrigerant.

  The indoor decompression mechanism 14a and the indoor decompression mechanism 14b control the flow rate of the refrigerant flowing through the indoor heat exchanger 12a and the indoor heat exchanger 12b. The indoor heat exchanger 12a and the indoor heat exchanger 12b include a use unit 303a. The refrigerant having a flow rate corresponding to the cooling load required in the air-conditioned space in which the use unit 303b is installed flows. The refrigerant that has cooled the indoor air in the indoor heat exchanger 12a and the indoor heat exchanger 12b flows out of the usage unit 303a and the usage unit 303b.

  The refrigerant that has flowed out of the use unit 303a and the use unit 303b flows through the second gas connection pipe 11a and the second gas connection pipe 11b, and passes through the first electromagnetic valve 9a and the first electromagnetic valve 9b to the low pressure connection pipe 24. And flows in. The refrigerant that has flowed into the low-pressure connection pipe 24 flows into the second decompression mechanism 22 and merges with the refrigerant that has passed through the bypass connection pipe 23.

  The merged refrigerant then flows into the heat source unit 301, passes through the fourth check valve 25, passes through the four-way valve 2 and the accumulator 30, and is sucked into the compressor 1 again.

In the cooling main operation, the cooling load and the heating load of the utilization unit 303 exist simultaneously, and the cooling load is larger than the heating load. Therefore, the evaporating temperature _Te is controlled by the operating frequency of the compressor 1 to control the cooling capacity of the cooling operation utilization unit 303 having the maximum differential temperature. Further, the condensing temperature T _c is controlled by the air volume of the outdoor fan 4 to control the heating capacity of the heating operation utilization unit 303 having the maximum temperature difference. In the use unit 303 in which the differential temperature is not maximum, the air conditioning capability is controlled by controlling the opening of the indoor decompression mechanism 14 according to the differential temperature.
Note that the opening degree of the indoor pressure reducing mechanism 14 of the cooling operation utilization unit 303 having the maximum temperature difference is controlled so as to prevent the liquid back from being generated in the compressor 1. Moreover, the opening degree of the indoor pressure-reducing mechanism 14 of the heating operation utilization unit 303 having the maximum temperature difference is largely controlled so that the performance of the indoor heat exchanger 12 is maximized.

  For example, in the operation state of FIG. 11, the utilization unit 303b among the cooling operation utilization units becomes maximum at a temperature difference of 4 ° C., and thus the cooling capacity of the utilization unit 303b is controlled by the compressor 1. Moreover, since the utilization unit 303c becomes the maximum at 2 degreeC of temperature difference among heating operation utilization units, the heating capacity of the utilization unit 303c is controlled by the outdoor air blower 4. The indoor decompression mechanism 14 controls the cooling capacity of the usage unit 303a and the heating capacity of the usage unit 303d.

<Warm operation mode>
In the warm-up operation mode, the four-way valve 2 is indicated by a broken line, that is, the discharge side of the compressor 1 is connected to the high-pressure connection pipe 6 via the fifth check valve 26, and the suction side of the compressor 1 is outdoor. It is in a state connected to the gas side of the heat exchanger 3. Moreover, all the utilization units 303 are heating operation modes, and the 1st solenoid valve 9 is closed and the 2nd solenoid valve 10 is controlled to open.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant flows into the relay unit 302 via the four-way valve 2 and the fifth check valve 26, and then flows into the gas-liquid separator 7. The refrigerant that has flowed into the gas-liquid separator 7 then flows into the utilization unit 303 after passing through the first gas connection pipe 8 and the second electromagnetic valve 10.

  The refrigerant that has flowed into the utilization unit 303 flows into the indoor heat exchanger 12, performs heat exchange with indoor air supplied by the indoor blower 13, condenses into high-pressure liquid refrigerant, and flows out of the indoor heat exchanger 12. . The refrigerant that has heated the indoor air in the indoor heat exchanger 12 is depressurized by the indoor pressure reducing mechanism 14 and becomes a gas-liquid two-phase or liquid-phase refrigerant having an intermediate pressure.

  The refrigerant that has passed through the indoor decompression mechanism 14 flows out of the use unit 303 and flows into the second heat exchange unit 21 through the second check valve 16. The first pressure reducing mechanism 20 is controlled to be fully closed.

  The refrigerant flowing into the high pressure side of the second heat exchange unit 21 releases heat to the refrigerant flowing through the low pressure side of the second heat exchange unit 21. Thereafter, the refrigerant flows into the second decompression mechanism 22 and is decompressed to become a low-pressure gas-liquid two-phase refrigerant.

  Here, the second pressure reducing mechanism 22 is controlled by the control unit 103 so that the opening between the high pressure and the intermediate pressure becomes a predetermined value. The differential pressure between the high pressure and the intermediate pressure is obtained by subtracting the pressure detected by the intermediate pressure sensor 209 from the pressure detected by the high pressure sensor 208. Since the second pressure reducing mechanism 22 controls the flow rate of the refrigerant flowing through the second pressure reducing mechanism 22 so that the differential pressure between the high pressure and the intermediate pressure becomes a predetermined value, the differential pressure between the high pressure and the intermediate pressure is A state having a predetermined value is obtained. In this way, the second decompression mechanism 22 is controlled so that the refrigerant having a flow rate corresponding to the heating operation load required in the air-conditioned space flows into the use unit 303.

  The refrigerant that has passed through the second decompression mechanism 22 is then heated by the refrigerant flowing on the high pressure side of the second heat exchange unit 21 on the low pressure side of the second heat exchange unit 21. Thereafter, the first heat exchange unit 19 is heated by the refrigerant flowing on the high pressure side of the first heat exchange unit 19, and flows into the low pressure connection pipe 24 via the bypass connection pipe 23.

  Thereafter, the refrigerant that flows into the heat source unit 301 and flows into the outdoor heat exchanger 3 via the sixth check valve 28 evaporates by exchanging heat with the outdoor air supplied by the outdoor blower 4 and is low pressure. Gas refrigerant. After that, after passing through the accumulator 30 via the four-way valve 2, it is sucked into the compressor 1 again.

In the all-warm operation, all the use units 303 are in the heating operation, and there is no cooling load, but only the heating load. Therefore, the heating temperature of the heating operation utilization unit 303 having the maximum temperature difference is controlled by controlling the condensation temperature T _c at the operation frequency of the compressor 1. Moreover, the performance of the outdoor heat exchanger 3 is maximized by maximizing the air volume of the outdoor fan 4. In the use unit 303 where the temperature difference is not the maximum, the heating capacity is controlled by controlling the opening of the indoor decompression mechanism 14 according to the temperature difference. Moreover, the opening degree of the indoor pressure-reducing mechanism 14 of the heating operation utilization unit 303 having the maximum temperature difference is largely controlled so that the performance of the indoor heat exchanger 12 is maximized.

  For example, in the operation state of FIG. 12, the differential temperature of the utilization unit 303a is a maximum of 3 ° C., so the heating capacity of the utilization unit 303b is controlled by the compressor 1. The indoor decompression mechanism 14 controls the heating capacity of other utilization units 303.

<Warm main operation mode>
The warm main operation mode described here is that the use unit 303a and the use unit 303b are in the cooling operation mode, and the use unit 303c and the use unit 303d are in the heating operation mode, but the operation operation in a state where the heating load is larger than the cooling load. Mode. In this warm main operation mode, the heating operation corresponds to one main operation of the present invention, and the cooling operation corresponds to the other sub operation of the present invention.
In this warm main operation mode, the four-way valve 2 is controlled similarly to the full warm operation mode. Further, the first solenoid valve 9a and the first solenoid valve 9b are opened, the second solenoid valve 10a and the second solenoid valve 10b are closed, the first solenoid valve 9c and the first solenoid valve 9d are closed, the second solenoid valve 10c, The second electromagnetic valve 10d is controlled to open.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-pressure gas refrigerant flows into the relay unit 302 via the four-way valve 2 and the fifth check valve 26 and then flows into the gas-liquid separator 7. The refrigerant that has flowed into the gas-liquid separator 7 passes through the first gas connection pipe 8 and then passes through the second electromagnetic valve 10c and the second electromagnetic valve 10d, and then the second gas connection pipe 11c and the second gas connection pipe. 11d and flows into the usage unit 303c and the usage unit 303d.

  The refrigerant that has flowed into the use unit 303c and the use unit 303d flows into the indoor heat exchanger 12c and the indoor heat exchanger 12d, and is condensed by exchanging heat with the indoor air supplied by the indoor blower 13c and the indoor blower 13d. It becomes a high-pressure liquid refrigerant and flows out of the indoor heat exchanger 12c and the indoor heat exchanger 12d. The refrigerant that has heated the indoor air in the indoor heat exchanger 12c and the indoor heat exchanger 12d is decompressed by the indoor decompression mechanism 14c and the indoor decompression mechanism 14d, and becomes a gas-liquid two-phase or liquid-phase refrigerant having an intermediate pressure.

  The refrigerant that has passed through the indoor decompression mechanism 14c and the indoor decompression mechanism 14d flows out of the use unit 303c and the use unit 303d and flows through the second liquid connection pipe 15c and the second liquid connection pipe 15d, and the second check valve 16c. It flows into the high pressure side of the second heat exchange section 21 via the second check valve 16d. The first pressure reducing mechanism 20 is controlled to be fully closed.

  The refrigerant that has flowed into the high pressure side of the second heat exchange unit 21 releases heat to the refrigerant that flows through the low pressure side of the second heat exchange unit 21 and flows out of the second heat exchange unit. The refrigerant is distributed to the refrigerant flowing through the third check valve 17a and the third check valve 17b.

  The refrigerant flowing into the second decompression mechanism 22 is decompressed to be in a low-pressure gas-liquid two-phase state, and flows into the low-pressure side of the second heat exchange unit 21. Here, the second pressure reducing mechanism 22 is controlled by the control unit 103 so that the opening between the high pressure and the intermediate pressure becomes a predetermined value.

  The refrigerant that has flowed into the second heat exchange unit 21 is heated by the refrigerant flowing on the high-pressure side of the second heat exchange unit 21 and flows out of the second heat exchange unit. Thereafter, the refrigerant flows into the low pressure side of the first heat exchange unit 19 and is heated by the refrigerant flowing on the high pressure side of the first heat exchange unit 19. After flowing out of the first heat exchanging part 19, it flows into the low pressure connection pipe 24 via the bypass connection pipe 23.

  On the other hand, the refrigerant flowing into the third check valve 17a and the third check valve 17b flows into the usage unit 303a and the usage unit 303b via the second liquid connection pipe 15a and the second liquid connection pipe 15b. The refrigerant flowing into the usage unit 303a and the usage unit 303b is first decompressed by the indoor decompression mechanism 14a and the indoor decompression mechanism 14b, and enters a low-pressure gas-liquid two-phase state and flows into the indoor heat exchanger 12a and the indoor heat exchanger 12b. . The refrigerant flowing into the indoor heat exchanger 12a and the indoor heat exchanger 12b exchanges heat with the indoor air supplied by the indoor blower 13a and the indoor blower 13b and evaporates to become a low-pressure gas refrigerant.

  The low-pressure gas refrigerant that has cooled the indoor air by the indoor heat exchanger 12a and the indoor heat exchanger 12b flows out of the indoor heat exchanger 12a and the indoor heat exchanger 12b, and is supplied to the second gas connection pipe 11a and the second gas connection pipe. 11b and flows out of the usage unit 303a and the usage unit 303b. The refrigerant that has flowed out of the use unit 303a and the use unit 303b flows into the low-pressure connection pipe 24 through the first electromagnetic valve 9a and the first electromagnetic valve 9b, flows into the second pressure reduction mechanism 22, and passes through the bypass connection pipe 23. It merges with the flowing refrigerant.

  The merged refrigerant flows into the heat source unit 301 and flows into the outdoor heat exchanger 3 via the sixth check valve 28. The refrigerant that has flowed into the outdoor heat exchanger 3 exchanges heat with the outdoor air supplied by the outdoor blower 4 to evaporate into a low-pressure gas refrigerant.

  After that, after passing through the accumulator 30 via the four-way valve 2, it is sucked into the compressor 1 again.

In the warm main operation, the heating load and the cooling load of the utilization unit 303 exist simultaneously, and the heating load is larger than the cooling load. Therefore, the heating temperature of the heating operation utilization unit 303 having the maximum temperature difference is controlled by controlling the condensation temperature T _c at the operation frequency of the compressor 1. Further, the evaporating temperature _Te is controlled by the air volume of the outdoor fan 4 to control the cooling capacity of the cooling operation utilization unit 303 having the maximum differential temperature. In the use unit 303 in which the differential temperature is not maximum, the air conditioning capability is controlled by controlling the opening of the indoor decompression mechanism 14 according to the differential temperature.
Note that the opening degree of the indoor pressure reducing mechanism 14 of the cooling operation utilization unit 303 having the maximum temperature difference is controlled so as to prevent the liquid back from being generated in the compressor 1. Moreover, the opening degree of the indoor pressure-reducing mechanism 14 of the heating operation utilization unit 303 having the maximum temperature difference is largely controlled so that the performance of the indoor heat exchanger 12 is maximized.

  For example, in the operation state of FIG. 13, the utilization unit 303d of the heating operation utilization units has the maximum at a temperature difference of 8 ° C., and thus the heating capacity of the utilization unit 303d is controlled by the compressor 1. Moreover, since the utilization unit 303a becomes the maximum at the temperature difference of 2 ° C. among the cooling operation utilization units, the cooling capacity of the utilization unit 303a is controlled by the outdoor fan 4. The indoor decompression mechanism 14 controls the cooling capacity of the usage unit 303b and the heating capacity of the usage unit 303c.

Embodiment 2.
<Device configuration>
FIG. 14 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus 200 according to Embodiment 2 of the present invention. The characteristic part of the air conditioning apparatus 200 will be described based on FIG.
The air conditioner 200 can perform a cooling operation or a heating operation selectively in each indoor unit by performing the compressor-type refrigeration cycle operation, and the cooling operation and heating selected in each indoor unit. It is a three-pipe multi-system air conditioner that can handle operation simultaneously. In the second embodiment, the difference from the first embodiment described above will be mainly described, and parts having the same functions as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted. And

  The air conditioner 200 includes a heat source unit 301, a use unit 303, and a branch unit 304. The heat source unit 301 and the branch unit 304 are connected by a high pressure gas connection pipe 35 and a low pressure gas connection pipe 36. Specifically, the discharge side of the compressor 1 is connected to the second electromagnetic valve 10, and the suction side of the compressor 1 is connected to the first electromagnetic valve 9. Further, the heat source unit 301 and the utilization unit 303 are connected by a liquid connection pipe 34. Specifically, the outdoor decompression mechanism 32 is connected to the indoor decompression mechanism 14 via the receiver 33.

  In addition, the air conditioner 200 removes the second branch portion having the second check valve 16 and the third check valve 17 from the air conditioner 100 according to the first embodiment, and performs outdoor heat exchange. An outdoor decompression mechanism 32 is connected between the vessel 3 and the liquid connection pipe 34, a first three-way valve 31 is connected as a flow path switching device instead of the four-way valve 2, and an outdoor decompression mechanism 32 is used as a reservoir instead of an accumulator. A receiver 33 is connected between the liquid connection pipe 34 and the liquid connection pipe 34.

  The air conditioner 200 controls each device mounted on the heat source unit 301, the usage unit 303a, the usage unit 303b, the usage unit 303c, and the usage unit 303d in accordance with each air conditioning load required for the usage unit 303. The all-cooling operation mode, the cooling main operation mode, the all-warming operation mode, or the warm main operation mode is executed.

<Cooling operation mode>
In the all-cooling operation mode, the first three-way valve 31 connects the discharge side of the compressor 1 and the gas side of the outdoor heat exchanger 3. Further, all the utilization units 303 are in the cooling operation mode, and the first electromagnetic valve 9 is controlled to be opened and the second electromagnetic valve 10 is controlled to be closed.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant is sent to the outdoor heat exchanger 3 via the first three-way valve 31 and is condensed by exchanging heat with outdoor air supplied by the outdoor blower 4. It becomes.

The high-pressure liquid refrigerant passes through the outdoor decompression mechanism 32 controlled to be fully opened, then passes through the receiver 33 and the liquid connection pipe 34, and flows into the utilization unit 303 after passing through the second liquid connection pipe 15.
Thereafter, the pressure is reduced by the indoor pressure reducing mechanism 14, and a low-pressure gas-liquid two-phase state is obtained and flows into the indoor heat exchanger 12. And it heat-exchanges with the indoor air supplied by the indoor air blower 13, evaporates, and turns into a low-pressure gas refrigerant.

  The low-pressure gas refrigerant that has cooled the indoor air in the indoor heat exchanger 12 flows out of the indoor heat exchanger 12, flows through the second gas connection pipe 11, and flows into the branch unit 304. Thereafter, it flows through the low pressure gas connection pipe 36 via the first electromagnetic valve 9 and is sucked into the compressor 1 again.

<Cold main operation mode>
The cooling main operation mode described here is that the use unit 303a and the use unit 303b are in the cooling operation mode, and the use unit 303c and the use unit 303d are in the heating operation mode, but the cooling operation load is larger than the heating operation load. It is a driving operation mode. In this cold main operation mode, the first three-way valve 31 is controlled in the same manner as in the all-cooling operation mode. Further, the first electromagnetic valve 9a and the first electromagnetic valve 9b are opened, the first electromagnetic valve 9c and the first electromagnetic valve 9d are closed, the second electromagnetic valve 10a and the second electromagnetic valve 10b are closed, the second electromagnetic valve 10c and The second electromagnetic valve 10d is controlled to open.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant is distributed to the refrigerant flowing in the outdoor heat exchanger 3 and the refrigerant flowing in the high-pressure gas connection pipe 35 via the first three-way valve 31. The refrigerant that has flowed into the high-pressure gas connection pipe 35 flows into the branch unit 304c and the branch unit 304d, passes through the second electromagnetic valve 10c and the second electromagnetic valve 10d, and passes through the second gas connection pipe 11c and the second gas connection pipe 11d. After passing, the flow enters the usage unit 303c and the usage unit 303d.

  In the usage unit 303c and the usage unit 303d, the indoor heat exchanger 12c and the indoor heat exchanger 12d exchange heat with the indoor air supplied by the indoor blower 13c and the indoor blower 13d to condense into a high-pressure liquid refrigerant. . Thereafter, the high-pressure liquid refrigerant is decompressed by the indoor decompression mechanism 14c and the indoor decompression mechanism 14d, and becomes an intermediate-pressure gas-liquid two-phase or liquid-phase refrigerant. Thereafter, the refrigerant merges with the refrigerant that has passed through the liquid connection pipe 34 via the second liquid connection pipe 15c and the second liquid connection pipe 15d.

  On the other hand, the refrigerant that has flowed into the outdoor heat exchanger 3 via the first three-way valve 31 performs heat exchange with the outdoor air supplied by the outdoor blower 4 and is condensed to become a high-pressure liquid refrigerant. The high-pressure gas refrigerant is decompressed by the outdoor decompression mechanism 32, passes through the liquid connection pipe 34 via the receiver 33, and passes through the second liquid connection pipe 15c and the second liquid connection pipe 15d to be liquid. The refrigerant that has passed through the connection pipe 34 merges.

  The merged refrigerant flows into the use unit 303a and the use unit 303b via the second liquid connection pipe 15a and the second liquid connection pipe 15b, and is reduced in pressure by the indoor pressure reduction mechanism 14a and the indoor pressure reduction mechanism 14b. It becomes a gas-liquid two-phase state. Then, it flows into the indoor heat exchanger 12a and the indoor heat exchanger 12b, performs heat exchange with the indoor air supplied by the indoor blower 13a and the indoor blower 13b, and evaporates to become a low-pressure gas refrigerant.

  Thereafter, the refrigerant that has flowed out of the indoor heat exchanger 12a and the indoor heat exchanger 12b flows out of the use unit 303a and the use unit 303b, flows through the second gas connection pipe 11a and the second gas connection pipe 11b, and enters the branch unit 304a, The branch unit 304b flows through the low pressure gas connection pipe 36 via the first electromagnetic valve 9a and the first electromagnetic valve 9b, and is again sucked into the compressor 1.

<Warm operation mode>
In the warm-up operation mode, the first three-way valve 31 connects the suction side of the compressor 1 and the gas side of the outdoor heat exchanger 3. Moreover, all the utilization units 303 are heating operation modes, and the 1st solenoid valve 9 is closed and the 2nd solenoid valve 10 is controlled to open.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant is sent to the high-pressure gas connection pipe 35 and flows into the branch unit 304.

  The refrigerant that has flowed into the branch unit 304 passes through the second electromagnetic valve 10 and flows into the utilization unit 303 via the second gas connection pipe 11. The utilization unit 303 flows into the indoor heat exchanger 12, exchanges heat with the indoor air supplied by the indoor blower 13, condenses into a high-pressure liquid refrigerant, and flows out of the indoor heat exchanger 12. The refrigerant that has flowed out of the indoor heat exchanger 12 is depressurized by the indoor depressurization mechanism 14, and becomes an intermediate-pressure gas-liquid two-phase or liquid refrigerant.

  The refrigerant that has passed through the indoor decompression mechanism 14 flows out of the use unit 303, flows to the liquid connection pipe 34 through the second liquid connection pipe 15, passes through the receiver 33, and flows to the outdoor decompression mechanism 32. The outdoor decompression mechanism 32 becomes a low-pressure gas-liquid two-phase refrigerant, and the outdoor heat exchanger 3 exchanges heat with outdoor air supplied by the outdoor blower 4 to evaporate to become a low-pressure gas refrigerant. Thereafter, the air is sucked again by the compressor 1 via the first three-way valve 31.

<Warm main operation mode>
The warm main operation mode described here is that the use unit 303a and the use unit 303b are in the cooling operation mode, and the use unit 303c and the use unit 303d are in the heating operation mode, but the heating operation load is larger than the cooling operation load. It is a driving operation mode. In this warm main operation mode, the four-way valve 2 is controlled similarly to the full warm operation mode. Further, the first solenoid valve 9a and the first solenoid valve 9b are opened, the second solenoid valve 10a and the second solenoid valve 10b are closed, the first solenoid valve 9c and the first solenoid valve 9d are closed, the second solenoid valve 10c, The second electromagnetic valve 10d is controlled to open.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-pressure gas refrigerant passes through the high-pressure gas connection pipe 35 and flows into the branch unit 304c and the branch unit 304d. The branch unit 304c and the branch unit 304d flow through the second electromagnetic valve 10c and the second electromagnetic valve 10d, flow through the second gas connection pipe 11c and the second gas connection pipe 11d, and flow into the use unit 303c and the use unit 303d.

  The refrigerant that has flowed into the use unit 303c and the use unit 303d flows into the indoor heat exchanger 12c and the indoor heat exchanger 12d, and is condensed by exchanging heat with the indoor air supplied by the indoor blower 13c and the indoor blower 13d. It becomes a high-pressure liquid refrigerant and flows out of the indoor heat exchanger 12c and the indoor heat exchanger 12d. The refrigerant that has flowed out of the indoor heat exchanger 12c and the indoor heat exchanger 12d is decompressed by the indoor decompression mechanism 14c and the indoor decompression mechanism 14d, and becomes an intermediate-pressure gas-liquid two-phase or liquid-phase refrigerant.

  The refrigerant that has passed through the indoor decompression mechanism 14c and the indoor decompression mechanism 14d flows out of the use unit 303c and the use unit 303d, flows through the second liquid connection pipe 15c and the second liquid connection pipe 15d, and then passes through the liquid connection pipe 34. The refrigerant is distributed to the flowing refrigerant and the refrigerant flowing through the second liquid connection pipe 15a and the second liquid connection pipe 15b.

  The refrigerant that has flowed through the liquid connection pipe 34 passes through the receiver 33 and flows to the outdoor decompression mechanism 32. The outdoor decompression mechanism 32 becomes a low-pressure gas-liquid two-phase refrigerant, and the outdoor heat exchanger 3 exchanges heat with outdoor air supplied by the outdoor blower 4 to evaporate to become a low-pressure gas refrigerant. Thereafter, the low-pressure gas refrigerant merges with the refrigerant flowing through the low-pressure gas connection pipe 36 via the first three-way valve 31.

  On the other hand, the refrigerant flowing through the second liquid connection pipe 15a and the second liquid connection pipe 15b flows into the utilization unit 303a and the utilization unit 303b, and is decompressed by the indoor decompression mechanism 14a and the interior decompression mechanism 14b. It becomes a phase state. Then, it flows into the indoor heat exchanger 12a and the indoor heat exchanger 12b, performs heat exchange with the indoor air supplied by the indoor blower 13a and the indoor blower 13b, and evaporates to become a low-pressure gas refrigerant.

  Thereafter, the refrigerant that has flowed out of the indoor heat exchanger 12a and the indoor heat exchanger 12b flows out of the use unit 303a and the use unit 303b, flows through the second gas connection pipe 11a and the second gas connection pipe 11b, and enters the branch unit 304a, The branch unit 304b flows through the low pressure gas connection pipe 36 via the first solenoid valve 9a and the first solenoid valve 9b, merges with the refrigerant that has passed through the outdoor heat exchanger 3, and is then sucked into the compressor 1 again. .

  The flow direction of the refrigerant in each operation mode in the three-tube multi-system air conditioner 200 according to Embodiment 2 has been described above. In each operation mode, as in the case of the air conditioner 100 of the first embodiment, the air conditioning capacity of the utilization unit 303 with the maximum differential temperature is controlled by controlling the evaporation temperature and the condensation temperature with the compressor 1 and the outdoor fan 4. It is possible to control the air conditioning capability of the utilization unit 303 whose differential temperature is not maximum by the indoor decompression mechanism 14 according to the differential temperature. Accordingly, since the compressor can be controlled in accordance with the load, the operation frequency is not excessively increased. Since the outdoor fan 4 is controlled by the air conditioning load, the amount of heat in the outdoor heat exchanger 3 is controlled corresponding to the air conditioning load. By controlling the compressor 1, the outdoor blower 4, and the indoor decompression mechanism 14 as described above, an efficient operation state is obtained. In addition, the air-conditioning capability corresponding to the air-conditioning load can be obtained in all the use units 303, and air-conditioning excellent in comfort without causing uncooling and non-warming is possible.

Embodiment 3.
<Device configuration>
FIG. 15 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus 300 according to Embodiment 3 of the present invention. The characteristic part of the air conditioning apparatus 300 is demonstrated based on FIG. The air conditioner 300 is a multi-system air conditioner that can perform a cooling operation or a heating operation in each indoor unit by performing the compressor-type refrigeration cycle operation. In the third embodiment, the difference from the first embodiment described above will be mainly described, and parts having the same functions as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted. And

  The air conditioner 300 includes a heat source unit 301 and a utilization unit 303. The heat source unit 301 and the utilization unit 303 are connected by a liquid connection pipe 34 and a gas connection pipe 37. The air conditioning apparatus 300 includes a first branching unit having the first electromagnetic valve 9 and the second electromagnetic valve 10 with respect to the air conditioning apparatus 100 according to the first embodiment, a second check valve 16 and a third check valve. 17 is removed, and the operation mode of the utilization unit 303 is all set to the heating operation or the cooling operation.

  The air conditioner 300 controls each device mounted on the heat source unit 301, the usage unit 303a, the usage unit 303b, the usage unit 303c, and the usage unit 303d in accordance with each air conditioning load required for the usage unit 303. The all-cooling operation mode or the all-warming operation mode is executed.

<Cooling operation mode>
In the all-cooling operation mode, the four-way valve 2 is shown by a solid line, that is, the discharge side of the compressor 1 is connected to the gas side of the outdoor heat exchanger 3, and the suction side of the compressor 1 passes through the accumulator 30. The gas connection pipe 37 is connected. All the use units 303 are in the cooling operation mode.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant is sent to the outdoor heat exchanger 3 via the four-way valve 2, exchanges heat with the outdoor air supplied by the outdoor blower 4, and is condensed to become a high-pressure liquid refrigerant. .

  The high-pressure liquid refrigerant passes through the liquid connection pipe 34 and flows into the usage unit 303 via the second liquid connection pipe 15. Thereafter, the pressure is reduced by the indoor pressure reducing mechanism 14, and a low-pressure gas-liquid two-phase state is obtained and flows into the indoor heat exchanger 12. And it heat-exchanges with the indoor air supplied by the indoor air blower 13, evaporates, and turns into a low-pressure gas refrigerant.

  Since the indoor decompression mechanism 14 controls the flow rate of the refrigerant flowing through the indoor heat exchanger 12, the indoor heat exchanger 12 has a flow rate according to the cooling load required in the air-conditioned space where the use unit 303 is installed. Refrigerant is flowing.

  The low-pressure gas refrigerant that has cooled the indoor air by the indoor heat exchanger 12 flows out from the indoor heat exchanger 12, flows through the second gas connection pipe 11, and flows out from the utilization unit 303. Thereafter, the gas flows into the heat source unit 301 via the gas connection pipe 37, passes through the four-way valve 2 and the accumulator 30, and is sucked into the compressor 1 again.

<Warm operation mode>
In the warm-up operation mode, the four-way valve 2 is indicated by a broken line, that is, the discharge side of the compressor 1 is connected to the gas connection pipe 37, and the suction side of the compressor 1 is connected to the gas side of the outdoor heat exchanger 3. It is in the state. Moreover, all the utilization units 303 are heating operation modes.

  When the compressor 1, the outdoor blower 4 and the indoor blower 13 are started in the state of this refrigerant circuit, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature / high-pressure gas refrigerant. Thereafter, the high-temperature and high-pressure gas refrigerant flows into the utilization unit 303 via the four-way valve 2 and the gas connection pipe 37. The refrigerant that has flowed into the utilization unit 303 flows into the indoor heat exchanger 12, performs heat exchange with indoor air supplied by the indoor blower 13, condenses into high-pressure liquid refrigerant, and flows out of the indoor heat exchanger 12. . The refrigerant flowing out of the indoor heat exchanger 12 is decompressed by the indoor decompression mechanism 14 and becomes a low-pressure gas-liquid two-phase refrigerant. Thereafter, the refrigerant that flows out of the utilization unit 303 and flows into the outdoor heat exchanger 3 through the second liquid connection pipe 15 and the liquid connection pipe 34 exchanges heat with the outdoor air supplied by the outdoor blower 4. It goes and evaporates to become a low-pressure gas refrigerant. After that, after passing through the accumulator 30 via the four-way valve 2, it is sucked into the compressor 1 again.

In the air conditioner 300 according to the third embodiment, for example, the condensation temperature T _c is calculated from the pressure detected by the discharge pressure sensor 201, and the evaporation temperature _Te is calculated from the indoor liquid temperature sensor 207 in the case of the all-cooling operation. The detected temperature may be the temperature detected by the outdoor liquid temperature sensor 204 in the full warm operation.

  Heretofore, the refrigerant flow direction in each operation mode in the multi-system air conditioner 300 according to Embodiment 3 has been described. In each operation mode, as in the case of the air conditioner 100 of the first embodiment, the air conditioning capacity of the utilization unit 303 with the maximum differential temperature is controlled by controlling the evaporation temperature and the condensation temperature with the compressor 1 and the outdoor fan 4. It is possible to control the air conditioning capability of the utilization unit 303 whose differential temperature is not maximum by the indoor decompression mechanism 14 according to the differential temperature. Accordingly, since the compressor can be controlled in accordance with the load, the operation frequency is not excessively increased. Further, the outdoor fan 4 is controlled in the amount of heat in the outdoor heat exchanger 3 corresponding to the air conditioning load. Even in a multi-system air conditioner that cannot be operated simultaneously with cooling and heating, an efficient operating state can be achieved by controlling the compressor 1, the outdoor blower 4, and the indoor pressure reducing mechanism 14 as described above. In addition, the air-conditioning capability corresponding to the air-conditioning load can be obtained in all the use units 303, and air-conditioning excellent in comfort without causing uncooling and non-warming is possible.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Outdoor heat exchanger, 4 Outdoor blower, 5 1st check valve, 6 High pressure connection piping, 7 Gas-liquid separator, 8 1st gas connection piping, 9 1st solenoid valve, 10 2nd solenoid valve, 11 2nd gas connection piping, 12 indoor heat exchanger, 13 indoor blower, 14 indoor decompression mechanism, 15 2nd liquid connection piping, 16 2nd check valve, 17 3rd check valve, 18 1st 1 liquid connection pipe, 19 1st heat exchange part, 20 1st pressure reduction mechanism, 21 2nd heat exchange part, 22 2nd pressure reduction mechanism, 23 bypass connection pipe, 24 low pressure connection pipe, 25 4th check valve, 26 1st 5 check valve, 27 first connection pipe, 28 sixth check valve, 29 second connection pipe, 30 accumulator, 31 first three-way valve, 32 outdoor pressure reducing mechanism, 33 receiver, 34 liquid connection pipe, 35 high pressure gas connection Piping, 36 Low-pressure gas connection piping, 37 Gas connection piping, 100 air conditioner, 200 air conditioner, 201 discharge pressure sensor, 202 outdoor gas temperature sensor, 203 outdoor air temperature sensor, 204 outdoor liquid temperature sensor, 205 indoor gas temperature sensor, 206 indoor suction temperature sensor, 207 indoor Liquid temperature sensor, 208 High pressure sensor, 209 Intermediate pressure sensor, 210 Intermediate pressure temperature sensor, 211 Low pressure saturation temperature sensor, 212 Low pressure gas temperature sensor, 213 Suction pressure sensor, 300 Air conditioner, 301 Heat source unit, 302 Relay Unit, 303 use unit, 304 branch unit.

Claims (14)

A plurality of usage units each equipped with a usage-side heat exchanger and an indoor decompression mechanism;
At least one heat source unit equipped with a compressor, a flow path switching device, a heat source side heat exchanger, and a heat source side blower;
A relay unit that is provided between the use unit and the heat source unit, and controls a flow of a refrigerant that flows into the use unit according to an operation state of the use unit;
In each operation of the use side heat exchanger of the use unit, an air conditioner capable of selecting cooling operation or heating operation,
Indoor decompression mechanism control means for controlling the indoor decompression mechanism provided in the utilization unit;
An air conditioning load performance amount calculating means for calculating the air conditioning load of each of the utilization units;
When the driver cooling operation of the plurality of user units and the heating operation are mixed, among the user units operating as the one main, the based on the air-conditioning load of the utilization unit air conditioning load is maximum Compressor control means for controlling the operating frequency of the compressor;
When the driver cooling operation of the plurality of user units and the heating operation are mixed, among the user units of the operation is the other slave, the based on the air-conditioning load of the utilization unit air conditioning load is maximum A heat source side blower control means for controlling the air volume of the heat source side blower,
The indoor decompression mechanism control means includes:
In the usage unit where the air conditioning load is maximum, the indoor pressure reducing mechanism of the usage unit is set so that the degree of superheat becomes a constant value in the cooling operation and the degree of supercooling becomes a constant value in the heating operation. Control to maximize the performance of the usage side heat exchanger of the usage unit ,
In the use unit where the air-conditioning load is not maximum, the indoor pressure reducing mechanism of the use unit is controlled based on the air-conditioning load . The relay unit is
Connected to the heat source unit via a first refrigerant pipe and a second refrigerant pipe;
A first branch portion that selectively connects one of the refrigerant inlets and outlets of the usage-side heat exchanger in the usage unit to the second refrigerant piping via the first refrigerant piping or a gas-liquid separator;
When the other refrigerant inlet / outlet of the usage-side heat exchanger in the usage unit is the refrigerant inlet, the refrigerant is connected to the gas-liquid separator via a first pressure reducing mechanism, and the refrigerant inlet / outlet of the usage-side heat exchanger in the usage unit A second branch portion connected to the outlet side of the first pressure reducing mechanism when the other of the refrigerant outlet is a refrigerant outlet;
A refrigerant circuit comprising a connection pipe having one end connected to the inlet side of the second branch portion and the other end connected to the first refrigerant pipe via a second decompression mechanism. Item 1. An air conditioner according to Item 1. The refrigerant circuit is
A first heat exchanging section for exchanging heat between a pipe connecting the gas-liquid separator and the first pressure reducing mechanism and a pipe connecting the second pressure reducing mechanism and the first connecting pipe. When,
A second for exchanging heat between a pipe connecting the first pressure reducing mechanism and the second branch portion and a pipe connecting the second pressure reducing mechanism and the first connection pipe. The air conditioner according to claim 2, further comprising a heat exchange unit. A plurality of usage units each equipped with a usage-side heat exchanger and an indoor decompression mechanism;
At least one heat source unit equipped with a compressor, a flow path switching device, a heat source side heat exchanger, a heat source side blower, and a heat source side pressure reducing mechanism;
A branching unit that is provided between a plurality of usage units and the usage unit, and that controls the flow of refrigerant that flows into the usage unit according to the operating state of the usage unit;
In each operation of the use side heat exchanger of the use unit, an air conditioner capable of selecting cooling operation or heating operation,
Indoor decompression mechanism control means for controlling the indoor decompression mechanism provided in the utilization unit;
An air conditioning load related quantity calculating means for calculating the air conditioning load of each of the utilization units;
When the driver cooling operation of the plurality of user units and the heating operation are mixed, among the user units operating as the one main, the based on the air-conditioning load of the utilization unit air conditioning load is maximum Compressor control means for controlling the operating frequency of the compressor;
When the driver cooling operation of the plurality of user units and the heating operation are mixed, among the user units of the operation is the other slave, the based on the air-conditioning load of the utilization unit air conditioning load is maximum A heat source side blower control means for controlling the air volume of the heat source side blower,
The indoor decompression mechanism control means includes:
In the usage unit where the air conditioning load is maximum, the indoor pressure reducing mechanism of the usage unit is set so that the degree of superheat becomes a constant value in the cooling operation and the degree of supercooling becomes a constant value in the heating operation. Control to maximize the performance of the usage side heat exchanger of the usage unit,
In the use unit where the air-conditioning load is not maximum, the indoor pressure reducing mechanism of the use unit is controlled based on the air-conditioning load . The compressor control means includes
Of the total value of the cooling load of the utilization unit performing the cooling operation and the total value of the heating load of the utilization unit performing the heating operation, the operation having the larger total value is defined as the one main operation. Control the operating frequency of the compressor,
The heat source side blower control means includes:
The air conditioner according to any one of claims 1 to 4, wherein the air volume of the heat source side blower is controlled by setting the operation with the smaller total value as the operation of the other subordinate. Intake air temperature detection means for detecting the intake air temperature of each of the plurality of utilization units,
The air conditioning apparatus according to any one of claims 1 to 5, wherein the air conditioning load related amount calculating means obtains the air conditioning load based on an intake air temperature and a set temperature of the utilization unit. Saturation temperature detection means for detecting the saturation temperature of the refrigerant;
A saturation temperature target calculation means for calculating a saturation temperature target value of the refrigerant,
The saturation temperature target calculation means calculates the saturation temperature target value based on the intake air temperature, the set temperature, and the refrigerant saturation temperature,
The air conditioner according to any one of claims 1 to 6, wherein the compressor control unit or the heat source side blower control unit performs a control operation based on the saturation temperature target value.   The air conditioner according to any one of claims 1 to 7, wherein the indoor pressure reducing mechanism control means controls the indoor pressure reducing mechanism opening degree by an intake air temperature and a set temperature. A liquid temperature detecting means for detecting a refrigerant liquid temperature of the use side heat exchanger;
Gas temperature detecting means for detecting the refrigerant gas temperature of the use side heat exchanger;
High pressure detecting means for detecting the pressure of the use side heat exchanger;
With
The indoor decompression mechanism control means includes:
When the usage unit is in cooling operation,
When the difference between the temperature detected by the gas temperature detecting means and the temperature detected by the liquid temperature detecting means is less than a threshold value, the temperature detected by the gas temperature detecting means and the liquid temperature detecting means are detected. The opening of the indoor pressure reducing mechanism is controlled so that the difference from the measured temperature becomes a threshold,
When the usage unit is in heating operation,
9. The air conditioner according to claim 8, wherein a control is performed so that a difference between a saturation temperature of the pressure detected by the high pressure detection means and a temperature detected by the liquid temperature detection means becomes the threshold value. . The indoor decompression mechanism control means includes:
Among the utilization units, the opening degree of the indoor pressure reducing mechanism of the utilization unit that maximizes the difference between the suction air temperature and the set temperature,
When the usage unit is in cooling operation, the difference between the temperature detected by the gas temperature detection means and the temperature detected by the liquid temperature detection means is controlled to be the threshold value,
When the utilization unit is in a heating operation, control is performed such that a difference between a saturation temperature of the pressure detected by the high pressure detection means and a temperature detected by the liquid temperature detection means becomes the threshold value. The air conditioning apparatus according to claim 9.   The air conditioning apparatus according to any one of claims 6 to 10, wherein the intake air temperature is an average value of intake air temperatures measured in the past.   The air conditioning apparatus according to any one of claims 6 to 10, wherein the suction air temperature is a predicted value obtained based on a suction air temperature measured in the past.   The said compressor control means or the said outdoor air blower control means performs control operation | movement according to the change of the operation number of the said utilization unit, or an operation mode, It is any one of Claims 1-12 characterized by the above-mentioned. Air conditioner. The heat source side air volume control means includes:
The air conditioner according to claim 2 or 3, wherein the air volume is controlled based on a pipe length and a height difference of the first refrigerant pipe and the second refrigerant pipe connecting the heat source unit and the relay unit. .

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