JP5132354B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner that can simultaneously process a cooling / heating load, and more particularly to an air conditioner that can efficiently process a cooling load.

  Conventionally, there exists an air conditioner such as a multi air conditioner that can simultaneously process a cooling load and a heating load. Such an air conditioner is generally provided with a four-way valve for switching the flow of refrigerant in the outdoor unit, and a plurality of outdoor units equipped with the four-way valve are mounted, and the outdoor units are combined. Yes. In such an air conditioner, a cooling load or a heating load is executed in each of the mounted outdoor units.

  As such, “a plurality of indoor units, a plurality of outdoor units, a liquid pipe and a gas pipe provided in each indoor unit and each outdoor unit, and a room provided in each indoor unit” In a multi air conditioner having an expansion valve, the gas pipes of each of the plurality of outdoor units are aggregated and connected to one end side, and the other end side is connected to one indoor unit side, The liquid pipes of the plurality of outdoor units are aggregated and connected to one end side thereof, and the other end side includes one common liquid pipe connected to the indoor unit side, and the one common gas pipe And one common liquid pipe is shared as a refrigerant transport pipe between each outdoor unit and each indoor unit during operation, and the indoor expansion valve of the indoor unit that stops operation is closed and the one common liquid pipe is closed. Blocking the flow of the refrigerant from the liquid pipe to the indoor unit that stops the operation, Inner expansion valve has been proposed that each controlled in accordance with the indoor load "(e.g., see Patent Document 1).

Japanese Patent No. 3005485 (page 4-5, FIG. 10)

  The air conditioner as described above is installed in a building such as a building that requires a cooling load throughout the year for cooling of OA machines, for example, and there is a cooling load in the winter, while the cooling load in the summer is more in the winter. Often higher than heating load. In such an air conditioner, it is necessary to connect a plurality of outdoor units having substantially the same configuration according to cooling with a large load, select a capacity, and process the cooling load. In this case, despite the fact that there is no load to perform heating operation in all outdoor units, all outdoor unit units will be equipped with functions that enable heating operation such as switching the flow with a four-way valve, etc. There was a problem of becoming expensive.

  The present invention has been made in order to solve the above-described problems. In a building that can simultaneously process a cooling load and a heating load, and the maximum cooling load is larger than the maximum heating load. The first object is to provide an inexpensive air conditioner. In addition to the first object, a second object is to provide an air conditioner that can easily select the capacity according to the cooling load.

An air conditioner according to the present invention includes at least one indoor unit on which an indoor heat exchanger and an indoor expansion device are mounted, and is connected to the indoor unit, and includes a first compressor, a flow path switching unit, and a first outdoor unit. A first outdoor unit on which a heat exchanger is mounted, a controller connected between the indoor unit and the first outdoor unit, and for causing a refrigerant to flow through the indoor unit according to an operation state of the indoor unit; A second outdoor unit for cooling operation that is connected between the first outdoor unit and the controller so as to be in parallel with the first outdoor unit, and is equipped with a second compressor, a second outdoor heat exchanger, and an expansion device. and the unit, provided in the controller, a first gas-liquid separator provided on the downstream side of a position of the first outdoor unit and second outdoor unit, and the controller, The second outdoor unit is provided between the first outdoor unit and the second outdoor unit, and is installed at a position downstream of the controller and upstream of the first outdoor unit and the second outdoor unit. A gas-liquid separator, and the second outdoor unit is controlled in accordance with a cooling load in the indoor unit to compensate for a cooling operation in the first outdoor unit, The second compressor is started when the operating frequency of the first compressor is increased to a predetermined frequency that is set, and the operating frequency of the first compressor is equal to the capacity when operating by itself. , And the capacity when the two of the second compressors are operated are set to be substantially equal .

  According to the air conditioning apparatus of the present invention, even when the cooling load becomes large in summer or the cooling load due to heat generation from OA equipment or the like, it is possible to cool by adding an inexpensive system, that is, the second outdoor unit. Increase capacity and handle cooling loads.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
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. Based on FIG. 1, the refrigerant circuit structure of the air conditioning apparatus 100 is demonstrated. The air conditioner 100 is installed in a building such as a building or a condominium, and can simultaneously process a cooling load and a heating load by using a refrigeration cycle (heat pump cycle) for circulating a refrigerant. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  The air conditioner 100 includes a first outdoor unit 51, a second outdoor unit 54, a flow dividing controller 52, and two indoor units 53 (an indoor unit 53a and an indoor unit 53b). The first outdoor unit 51 and the shunt controller 52 are connected by a first low-pressure pipe 101 that is a refrigerant pipe and a first high-pressure pipe 102 that is a refrigerant pipe. That is, the outlet of the check valve 5b and the first gas-liquid separator 11 are connected via the first high-pressure pipe 102, and the inlet of the check valve 5a and the second on-off valve 13 (second on-off valve 13a and The second on-off valve 13b) is connected via the first low-pressure pipe 101 and the bypass pipe 110.

  The second outdoor unit 54 has an outlet of the second outdoor heat exchanger 32 connected to the first high-pressure pipe 102 via a second high-pressure pipe 106 that is a refrigerant pipe, and an inlet of the second accumulator 34 is a refrigerant. The first low pressure pipe 101 is connected via a second low pressure pipe 105 and a second gas-liquid separator 36 which are pipes. That is, the second outdoor unit 54 is connected to and mounted on the shunt controller 52 so as to be in parallel with the first outdoor unit 51. The details of the configuration and operation of the second gas-liquid separator 36 will be described with reference to FIG.

  Further, the shunt controller 52 and the indoor unit 53 are connected by a liquid pipe 103 (liquid pipe 103a and liquid pipe 103b) that is a refrigerant pipe and a gas pipe 104 (gas pipe 104a and gas pipe 104b) that are refrigerant pipes. . That is, the outlet of the second refrigerant heat exchanger 17 and the indoor throttle device 23 (the indoor throttle device 23a and the indoor throttle device 23b) are connected via the liquid pipe 103, and the first on-off valve 12 (first on-off valve). 12 a and the first on-off valve 12 b) and the second on-off valve 13 and the indoor heat exchanger 22 (the indoor heat exchanger 22 a and the indoor heat exchanger 22 b) are connected via a gas pipe 104.

[First outdoor unit 51]
The first outdoor unit 51 has a function of supplying a refrigerant for causing the indoor unit 53 to perform a cooling operation or a heating operation. The first outdoor unit 51 includes a first compressor 1, a four-way valve 3 serving as a flow path switching unit, a first The outdoor heat exchanger 2 and the first accumulator 4 are connected in series. In the first outdoor unit 51, the first high-pressure pipe 102 and the first low-pressure pipe 101 are connected by the first connection pipe 130 and the second connection pipe 131. Further, the first outdoor unit 51 includes four check valves (a check valve 5a, a check valve 5b, a check valve 5c, and a check valve) that control the flow of the refrigerant by allowing only one of the refrigerants to flow. A valve 5d) is provided.

  The check valve 5a includes a connection part c between the first low-pressure pipe 101 and the first connection pipe 130, and a connection part d (downstream of the connection part c) between the first low-pressure pipe 101 and the second connection pipe 131. The refrigerant is allowed to flow only in the direction from the flow dividing controller 52 to the first outdoor unit 51. The check valve 5b includes a connection part a between the first high-pressure pipe 102 and the first connection pipe 130, a connection part b between the first high-pressure pipe 102 and the second connection pipe 131 (downstream side of the connection part a), The refrigerant is allowed to flow only in the direction from the first outdoor unit 51 to the flow dividing controller 52. The check valve 5 c and the check valve 5 d are provided in the first connection pipe 130 and the second connection pipe 131, and allow the refrigerant to flow only in the direction from the first low pressure pipe 101 to the first high pressure pipe 102. It is supposed to be.

  The first compressor 1 sucks refrigerant and compresses the refrigerant to be in a high temperature / high pressure state. For example, the first compressor 1 may be configured of a type whose rotational speed is controlled by an inverter. The four-way valve 3 switches the refrigerant flow. The first outdoor heat exchanger 2 functions as an evaporator or a radiator (condenser), performs heat exchange between air supplied from a blower such as a fan (not shown) and the refrigerant, and converts the refrigerant into an evaporative gas. Or it is condensed and liquefied. The 1st accumulator 4 is arrange | positioned between the four-way valve 3 and the 1st compressor 1, and stores an excess refrigerant | coolant. In addition, the 1st accumulator 4 should just be a container which can store an excess refrigerant | coolant.

[Second outdoor unit 54]
The second outdoor unit 54 has a function of supplying a refrigerant for causing the indoor unit 53 to perform only a cooling operation, and includes a second compressor 31, a second outdoor heat exchanger 32, and a second accumulator 34. An opening / closing device 35 such as a diaphragm device is connected in series. That is, unlike the first outdoor unit 51, a four-way valve as a flow path switching unit is not provided. Therefore, the second outdoor unit 54 has a function of compensating the cooling load in the first outdoor unit 51 by allowing the refrigerant to flow in only one direction so as to perform only the cooling operation.

  The second compressor 31 sucks the refrigerant in the same manner as the first compressor 1 and compresses the refrigerant to a high temperature / high pressure state. Unlike the first outdoor heat exchanger 2, the second outdoor heat exchanger 32 functions only as a radiator (condenser) and heats between air supplied from a blower such as a fan (not shown) and the refrigerant. Exchange is performed to condense the refrigerant into a condensed liquid. The second accumulator 34 is disposed on the upstream side of the second compressor 31 and stores excess refrigerant. The opening / closing device 35 functions as a pressure reducing valve or an expansion valve, and decompresses the refrigerant to expand it. The opening / closing device 35 may be configured by a device whose opening degree can be variably controlled, for example, a precise flow rate control means using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, or the like. The second accumulator 34 may be any container that can store excess refrigerant.

[Diversion controller 52]
The shunt controller 52 connects the indoor unit 53a and the indoor unit 53b to the first outdoor unit 51 and the second outdoor unit 54, and each of the indoor unit 53a and the indoor unit 53b is a cooling unit or a heating unit. It has a function of controlling the flow of the refrigerant to determine. That is, the diversion controller 52 functions as a controller that causes the indoor unit 53 to conduct the refrigerant in accordance with the operation status of the indoor unit 53. The shunt controller 52 includes the first gas-liquid separator 11, the first on-off valve 12, the second on-off valve 13, the first throttling device 14, the second throttling device 15, and the first refrigerant heat exchanger 16. And the second refrigerant heat exchanger 17.

  The first gas-liquid separator 11 includes a first outdoor unit 51 via a first high-pressure pipe 102, a second outdoor unit 54 via a first high-pressure pipe 102 and a second high-pressure pipe 106, and a refrigerant pipe (hereinafter, The first refrigerant heat exchanger 16 is connected to the first on-off valve 12 via a refrigerant pipe (hereinafter referred to as a connection pipe 112) via a connection pipe 111). That is, the connection pipe 112 is branched into two, and connects the first gas-liquid separator 11 with the first on-off valve 12a and the first on-off valve 12b. That is, the first on-off valve 12 is provided in each of the branched connection pipes 112.

  The second on-off valve 13 is connected to the first low-pressure pipe 101 and is provided in the bypass pipe 110 that connects the first refrigerant heat exchanger 16 and the second refrigerant heat exchanger 17. That is, the bypass pipe 110 is branched into two, and the second on-off valve 13 is provided for each of them. The first expansion device 14 is provided in the connection pipe 111 between the first refrigerant heat exchanger 16 and the second refrigerant heat exchanger 17. The second expansion device 15 is provided in the bypass pipe 110 on the upstream side of the second refrigerant heat exchanger 17. The first refrigerant heat exchanger 16 is provided in the connection pipe 111 between the first gas-liquid separator 11 and the first expansion device 14. The second refrigerant heat exchanger 17 is provided in the connection pipe 111 between the first expansion device 14 and the second expansion device 15.

  The first gas-liquid separator 11 has a function of separating the flowing refrigerant into a gas refrigerant and a liquid refrigerant. The first on-off valve 12 and the second on-off valve 13 have a function of determining whether one of the indoor units 53 to be connected is a cooling unit or a heating unit by selectively opening and closing one of them. Have. The first throttling device 14 and the second throttling device 15 have a function of depressurizing and expanding the refrigerant, and can control the opening degree variably, for example, a precise flow control means using an electronic expansion valve, It may be configured by an inexpensive refrigerant flow rate adjusting means such as a capillary tube.

  The first refrigerant heat exchanger 16 includes a refrigerant that is conducted through the connection pipe 111 between the first gas-liquid separator 11 and the first expansion device 14, the second refrigerant heat exchanger 16, and the second on-off valve 13. Heat exchange with the refrigerant that is conducted through the bypass pipe 110 between the two. The second refrigerant heat exchanger 17 is connected between the second expansion device 15 and the first refrigerant heat exchanger 16 through the connection pipe 111 between the second expansion device 15 and the indoor unit 53. Heat exchange is performed with the refrigerant that is conducted through the bypass pipe 110.

[Indoor unit 53]
The indoor unit 53 has a function as a cooler or a heater, and the indoor expansion device 23 and the indoor heat exchanger 22 are connected in series and mounted. That is, in the indoor unit 53a, the indoor expansion device 23a and the indoor heat exchanger 22a are connected in series, and in the indoor unit 53b, the indoor expansion device 23b and the indoor heat exchanger 22b are connected in series. In addition, the indoor unit 53 a and the indoor unit 53 b are connected in parallel to the shunt controller 52 via the gas pipe 104 and the liquid pipe 103.

  The indoor expansion device 23 functions as a pressure reducing valve or an expansion valve, and expands the refrigerant by reducing the pressure. The indoor throttle device 23 may be configured by a device whose opening degree can be variably controlled, for example, a precise flow rate control means using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, or the like. The indoor heat exchanger 22 functions as a radiator (condenser) and an evaporator, exchanges heat between air supplied from a blower means (not shown) and the refrigerant, and condenses or liquefies the refrigerant. Is.

  The air conditioning apparatus 100 is provided with various detection means. In the first outdoor unit 51, the first high-pressure detection sensor 201 for detecting the pressure (high pressure) of the refrigerant discharged from the first compressor 1 to the discharge-side piping of the first compressor 1 is provided in the first compressor 1. A first low pressure detection sensor 202 for detecting the pressure (low pressure) of the refrigerant sucked into the first compressor 1 is installed in each of the suction side pipes. In the second outdoor unit 54, a second high pressure detection sensor 206 for detecting the pressure (high pressure) of the refrigerant discharged from the second compressor 31 to the discharge side piping of the second compressor 31 is provided in the second compressor 31. A second low pressure detection sensor 207 for detecting the pressure (low pressure) of the refrigerant sucked into the second compressor 31 is installed in each of the suction side pipes.

  In the shunt controller 52, a third low-pressure detection sensor 203 for detecting the pressure (low pressure) of the refrigerant passing through the first low-pressure pipe 101 and the inside of the first low-pressure pipe 101 is connected to the first high-pressure pipe 102. A third high-pressure detection sensor 204 for detecting the pressure (high pressure) of the refrigerant that is conducted through the high-pressure pipe 102 is disposed between the first throttling device 14 and the second throttling device 15 in the refrigerant pipe between them. An intermediate pressure detection sensor 205 for detecting the intermediate pressure of the refrigerant that conducts is installed. Further, in the shunt controller 52, a temperature sensor 210 that detects the temperature of the refrigerant that is conducted through the bypass pipe 110 is installed in the bypass pipe 110 on the downstream side of the first refrigerant heat exchanger 16.

  In the indoor unit 53, a first indoor unit temperature sensor 208 (a first temperature sensor 208) for detecting the temperature of the refrigerant that is conducted through the gas pipe 104 to the gas pipe 104 between the indoor heat exchanger 22 and the first on-off valve 12. The indoor unit temperature sensor 208a and the first indoor unit temperature sensor 208b) detect the temperature of the refrigerant that is connected to the refrigerant pipe between the indoor expansion device 23 and the indoor heat exchanger 22 through the refrigerant pipe. Unit temperature sensors 209 (second indoor unit temperature sensor 209a and second indoor unit temperature sensor 209b) are respectively installed. And the information detected by these detection means is sent to each control apparatus shown in FIG.

  FIG. 2 is an explanatory diagram for explaining a mechanism for operating an actuator based on information from each detection means. FIG. 3 is a timing chart for explaining the flow of communication transmitted and received between control devices. 2 and 3, each control device (control device 51A, control device 54A, control device 52A and control device 53A) is operated by an actuator (first compressor 1, second compressor 31) based on information from each detection means. The mechanism for operating the opening / closing device 35, the first expansion device 14, the second expansion device 15, the first on-off valve 12, the second on-off valve 13, and the indoor expansion device 23) is detailed based on communication between the control devices. Explained.

  In FIG. 2, the control device 51A is the control device for the first outdoor unit 51, the control device 52A is the control device for the shunt controller 52, the control device 53A is the control device for each indoor unit 53, and the control device 54A is the second outdoor unit. The control devices of the unit 51 are shown respectively. These control devices can communicate signals with each other by a control signal line or a radio wave. The control unit 53A of the indoor unit 53 can communicate signals with the remote controller 55 by radio waves or the like, and the user can set the start / stop of each indoor unit 53, set the temperature, and set the air volume / wind direction via the remote controller 55. The information from can be conveyed.

  When the operation instruction from the user is transmitted to the control device 53A of the indoor unit 53 via the remote controller 55, the control device 53A determines the rotational speed of the fan (not shown) of the indoor unit 53 and the opening degree of the indoor expansion device 23. The initialization is performed and the information is transmitted to the control device 51A and the control device 52A. Thereafter, a thermo determination is made based on the temperature information (TG) from the first indoor unit temperature sensor 208 and the temperature information (TL) from the second indoor unit temperature sensor 209, and the indoor throttling device 23 is opened according to the determination result. Adjust the degree.

  The control device 51A that has received the operation command information from the control device 53A initializes the rotational speed (AK1) of the outdoor fan (not shown) and the operation frequency (F1) of the first compressor 1, and thereafter the first high pressure Pressure information (PD1) from the detection sensor 201, pressure information (PS1) from the first low-pressure detection sensor 202, temperature information (TB) from the temperature sensor 210 transmitted from the control device 52A, and information transmitted from the control device 53A. The outdoor fan and the first compressor 1 are driven in accordance with temperature information (TG) from the first indoor unit temperature sensor 208 and temperature information (TL) from the second indoor unit temperature sensor 209 transmitted from the control device 53A. Adjust.

  Further, the control device 51A instructs the control device 54A of the second outdoor unit 54 according to the load status of the indoor unit 53 (the rotational speed (AK2) of the outdoor fan (not shown) and the operating frequency of the second compressor 31 ( F2) initial setting) is transmitted. Upon receipt of the command from the control device 51A, the control device 54A opens the opening / closing device 35 and drives the outdoor fan and the second compressor 31. After that, pressure information (PD2) from the second high-pressure detection sensor 206 and The driving of the outdoor fan and the second compressor 31 is adjusted according to the pressure information (PS2) from the second low-pressure detection sensor 207. As shown in FIG. 2, the control device 51 </ b> A may adjust the driving of the outdoor fan and the second compressor 31.

  The control device 52A that has received the operation command information from the control device 53A opens the on-off valve (either the first on-off valve 12 or the second on-off valve 13) corresponding to the indoor unit 53 in which the remote controller 55 is operated. At the same time, the opening degree of the first throttling device 14 (LEV1) and the second throttling device 15 (LEV2) is set. Thereafter, the pressure information (PL) from the third low-pressure detection sensor 203 and the third high-pressure detection sensor 204 are set. Open / close valves, the first throttling device 14 and the second throttling device 15 are opened according to the pressure information (PH) and the pressure information (PM) from the intermediate pressure detection sensor 205 and the temperature information (TB) from the temperature sensor 210. Correct the degree. The operating capacities of the first outdoor heat exchanger 2 and the second outdoor heat exchanger 32 can be expressed by AK1 and AK2 which are the rotational speeds of the outdoor fans.

  Here, operation | movement of the air conditioning apparatus 100 is demonstrated. First, the operation when the all-indoor unit 53 is in the cooling operation (hereinafter referred to as the all-cooling operation) will be described in correspondence with the flow of the refrigerant. The gas refrigerant heated to high temperature and high pressure by the first compressor 1 is discharged from the first compressor 1 and flows into the first outdoor heat exchanger 2 through the four-way valve 3. In this 1st outdoor heat exchanger 2, the gas refrigerant which flowed in is heat-exchanged with outdoor air, and is condensed and liquefied. The refrigerant that has flowed out of the first outdoor heat exchanger 2 passes through the check valve 5 b and is guided to the first high-pressure pipe 102. The high-pressure liquid refrigerant conducted through the first high-pressure pipe 102 is cooled by the first refrigerant heat exchanger 16 via the first gas-liquid separator 11 of the shunt controller 52 to increase the degree of supercooling, and the first expansion device After being squeezed until it becomes an intermediate-pressure liquid refrigerant at 14, a part is distributed to the liquid pipe 103 and the rest is distributed to the second expansion device 15.

  The liquid refrigerant conducted through the liquid pipe 103 is throttled to a low pressure by the indoor throttle device 23 and flows into the indoor heat exchanger 22. In the indoor heat exchanger 22, the liquid refrigerant that has flowed takes heat from the surrounding outdoor air and evaporates and gasifies. At this time, the cooling target area in the place where the indoor unit 53 is installed is cooled. The refrigerant flowing out of the indoor heat exchanger 22 is conducted through the gas pipe 104 and is guided to the first low-pressure pipe 101 through the second on-off valve 13 and the bypass pipe 110.

  On the other hand, the liquid refrigerant that has flowed into the second expansion device 15 is throttled to a low pressure by the second expansion device 15, and from the first gas-liquid separator 11 by the second refrigerant heat exchanger 17 and the first refrigerant heat exchanger 16. Heat exchanges with the flowing liquid refrigerant to evaporate and gasify. At this time, the liquid refrigerant flowing from the first gas-liquid separator 11 is supercooled. The refrigerant that has flowed out of the first refrigerant heat exchanger 16 merges with the gas refrigerant that has flowed out of the indoor unit 53, and conducts the first low-pressure pipe 101. The gas refrigerant passing through the first low-pressure pipe 101 returns to the first compressor 1 via the second gas-liquid separator 36, the check valve 5 a, the four-way valve 3, and the first accumulator 4.

  Next, the operation when the cooling load required for the air conditioner 100 is large will be described. In the operation when the cooling load is large, the flow of the refrigerant discharged from the first compressor 1 is as described above, and therefore will be described in correspondence with the flow of the refrigerant discharged from the second compressor 31. When the cooling load required for the air conditioner 100 is large, not only the first compressor 1 of the first outdoor unit 51 is driven but also the second compressor 31 of the second outdoor unit 54 is driven. It is supposed to be.

  The gas refrigerant driven to high temperature and high pressure by the second compressor 31 is discharged from the second compressor 31 and flows into the second outdoor heat exchanger 32. In the second outdoor heat exchanger 32, the flowing gas refrigerant exchanges heat with outdoor air and condenses and liquefies. Further, by opening the opening / closing device 35, the refrigerant flowing out from the second outdoor heat exchanger 32 is guided to the first high pressure pipe 102 via the second high pressure pipe 106 and condensed in the first outdoor heat exchanger 2. -Merged with the liquefied liquid refrigerant and flows into the diversion controller 52. The liquid refrigerant that has flowed into the diversion controller 52 cools the cooling target area where the indoor unit 53 is installed as described above, and is evaporated and gasified by the indoor heat exchanger 22 before being connected to the gas pipe 104. And flows into the second gas-liquid separator 36.

  In the second gas-liquid separator 36, the gas refrigerant and the refrigerating machine oil flowing in the gas refrigerant or along the inner wall surface are separated. Then, the gas refrigerant and the refrigerating machine oil flow out from the second gas-liquid separator 36 and are led to the first outdoor unit 51 side and the second outdoor unit 54 side (second low pressure pipe 105 side). The gas refrigerant containing the refrigerating machine oil that has flowed to the first outdoor unit 51 side returns to the first compressor 1 via the check valve 5 a, the four-way valve 3, and the first accumulator 4. On the other hand, the gas refrigerant including the refrigerating machine oil that flows to the second outdoor unit 54 side returns to the second compressor 31 via the second accumulator 34.

  FIG. 4 is a schematic structural diagram showing an example of the structure of the second gas-liquid separator 36. Based on FIG. 4, the structural example of the 2nd gas-liquid separator 36 is demonstrated. As shown in FIG. 1, the second gas-liquid separator 36 is provided in the first low-pressure pipe 101 between the first outdoor unit 51 and the branch flow controller 52, and the second accumulator 34 and the second low-pressure separator 36 are provided. They are connected via a pipe 105. The second gas-liquid separator 36 has a function of separating the refrigerant flowing into gas refrigerant and refrigerating machine oil flowing in the gas refrigerant or along the inner wall surface.

  As shown in FIG. 4, the second gas-liquid separator 36 is configured by connecting an inflow pipe 42, an outflow pipe 43 a, and an outflow pipe 43 b to a body 41. The inflow pipe 42 is connected to the first low-pressure pipe 101 so that the refrigerant flows from the first low-pressure pipe 101. The outflow pipe 43 a is connected to the first low-pressure pipe 101 so that the refrigerant flows out toward the first outdoor unit 51. The outflow pipe 43 b is connected to the second low-pressure pipe 105 so that the refrigerant flows out toward the second outdoor unit 54.

  The outflow pipe 43a and the outflow pipe 43b are configured by using a U-shaped pipe as shown in FIG. 4, the U-shaped apex portion is at the lowermost portion, and the tip portion is above the inside of the body 41 ( It suffices if it is above the horizontal center line of the body 41). The oil return holes 44a and the oil return holes 44b for sucking the refrigerating machine oil (not shown) accumulated in the lower part of the body 41 are opened at the U-shaped apexes of the outflow pipe 43a and the outflow pipe 43b. Is formed. That is, the refrigerating machine oil flowing downward in the gas refrigerant flowing into the second gas-liquid separator 36 or along the inner wall surface of the body 41 passes through the oil return hole 44a and the oil return hole 44b, and the first outdoor unit 51 and the second The unit is returned to the outdoor unit 54.

  Here, the operation in the second gas-liquid separator 36 will be described in detail. The refrigerating machine oil that flows into and accumulates in the second gas-liquid separator 36 is taken out together with the refrigerant discharged when the first compressor 1 and the second compressor 31 are driven. It is necessary to return to the second compressor 31. Therefore, in the second gas-liquid separator 36, the gas refrigerant containing the refrigeration oil flowing into the fuselage 41 from the inflow pipe 42 is once separated inside the fuselage 41, and the gas refrigerant is accumulated in the upper part and the refrigeration oil is accumulated in the lower part. ing.

  Here, when the gas refrigerant accumulated in the fuselage 41 flows from the front ends of the outflow pipe 43a and the outflow pipe 43b in the fuselage 41, the fuselage is caused by pressure loss in the U-shaped outflow pipe 43a and the outflow pipe 43b. A static pressure difference is generated between the inside 41 and the inside of the outflow pipe 43a and the outflow pipe 43b. By utilizing the occurrence of the static pressure difference, the refrigeration oil flows into the outflow pipe 43a and the outflow pipe 43b from the oil return hole 44a and the oil return hole 44b, and flows out from the second gas-liquid separator 36 together with the gas refrigerant.

  Further, the static pressure difference between the inside of the body 41 and the inside of the outflow pipe 43a and the outflow pipe 43b tends to increase as the amount of the gas refrigerant flowing into the outflow pipe 43a and the outflow pipe 43b increases. The amount of refrigerating machine oil corresponding to the flow can be caused to flow into the outflow pipe 43a and the outflow pipe 43b. The second gas-liquid separator 36 is not limited to the structure shown in FIG. For example, when the gas-liquid distribution has a shape that can be controlled in advance by a test or the like and the installation method is such that the refrigerant outlet is horizontal, the two-port distribution as shown in FIG. The second gas-liquid separator 36 may be configured in a vessel structure.

  FIG. 5 is a schematic structural diagram showing another example of the structure of the second gas-liquid separator 36. Based on FIG. 5, another structural example of the second gas-liquid separator 36 will be described. In FIG. 4, the case where the U-shaped outflow pipe 43a and the outflow pipe 43b are provided has been described as an example. However, in FIG. 5, the case where the second gas-liquid separator 36 is a two-port distributor will be described as an example. . As shown in FIG. 5, the second gas-liquid separator 36 has a body 47 as a two-port distributor. That is, the body 47 has a bifurcated structure in which one refrigerant inlet (hereinafter referred to as the inflow portion 45) and two refrigerant outlets (hereinafter referred to as the outflow portion 46a and the outflow portion 46b) are formed. -ing In order to achieve such a structure, it is required that the gas-liquid distribution can be controlled in advance by a test or the like, and the refrigerant outflow portions (outflow portion 46a and outflow portion 46b) are installed horizontally.

  The operation of the second gas / liquid separator 36 will be described. In the second gas-liquid separator 36, when the gas refrigerant containing the refrigeration oil flowing into the body 47 from the inflow part 45 flows out of the body 41, it is distributed to the outflow part 46a and the outflow part 46b. The outflow part 46a and the outflow part 46b are installed substantially in parallel. Therefore, the refrigerating machine oil is divided into two together with the gas refrigerant and flows out from the second gas-liquid separator 36 toward the first outdoor unit 51 and the second outdoor unit 54. Here, the case where the second gas-liquid separator 36 is a two-port distributor has been described as an example. However, the present invention is not limited to this, and the distribution number can be determined according to the number of connected outdoor units. That's fine.

  FIG. 6 is a flowchart showing a flow of control of the operating frequency of the first compressor 1 and the rotational speed of the outdoor fan. Based on FIG. 6, the flow of control of the operating frequency of the first compressor 1 and the rotational speed of the outdoor fan (not shown) of the first outdoor unit 51 will be described. First, the control device 51A acquires the high pressure PD (pressure information (PD1) from the first high pressure detection sensor 201) and the low pressure PS (pressure information (PS1) from the first low pressure detection sensor 202) (step S101). The control device 51A calculates the residuals of the target values PDm and PSm and the detected values for the acquired high pressure PD and low pressure PS (step S102).

  The control device 51A calculates the correction value ΔF of the operating frequency of the first compressor 1 and the correction value ΔAK of the rotational speed of the outdoor fan according to the residual (step S103). Here, it is assumed that the numerical values a, b, c, and d are constants obtained in advance by a test. Next, the control device 51A calculates the new control values F and AK by adding the correction values ΔF and ΔAK to the current control values F * and AK * (step S104). Thereafter, the control device 51A determines whether or not a predetermined time has elapsed (step S105). When the control device 51A determines that a predetermined time has elapsed (step S105; YES), the process returns to step S101 and the same correction calculation is performed.

  Next, a method of controlling the operating frequency of the first compressor 1 of the first outdoor unit 51 and the rotational speed of the outdoor fan, and the operating frequency of the second compressor 31 of the second outdoor unit 54 and the rotational speed of the outdoor fan. Will be described. The control device 51A that has received the operation command from the remote controller 55 via the control device 53A first determines the initial value of the operation frequency (F1) of the first compressor 1 according to the outside air temperature, room temperature, and operation capacity. The initial value of the rotation speed (AK1) of the outdoor fan is set. Thereafter, the control device 51A corrects the operating frequency of the first compressor 1 according to the flowchart of FIG. 6, and the control device is configured to operate the second compressor 31 when the correction result becomes equal to or higher than the predetermined operating frequency. A command is issued to 54A.

  The control device 54A that has received the command sets the operation frequency (F2) and the rotational speed (AK2) of the outdoor fan that are transmitted together with the operation command of the second compressor 31, and starts the second compressor 31 and the outdoor fan. . And in the state in which the 1st outdoor unit 51 and the 2nd outdoor unit 54 are drive | operating together, according to the flowchart of FIG. 6, the operating frequency of the 1st compressor 1 was correct | amended and the correction result became below predetermined operating frequency. At the time, the controller 51A issues a command to the controller 54A so as to stop the operation of the second compressor 31. Receiving the command, the control device 54A stops the operation of the second compressor 31 and the outdoor fan.

  FIG. 7 is a graph for explaining the operating frequency of the compressor (both the first compressor 1 and the second compressor 31). Based on FIG. 7, the operating frequency of the compressor according to the cooling load will be described in detail. In FIG. 7, the horizontal axis indicates the total operating frequency of the compressor, and the vertical axis indicates the operating frequency divided into the first compressor 1 and the second compressor 31. The air conditioner 100 drives only the first compressor 1 of the first outdoor unit 51 when the cooling load is small, and when the cooling load becomes large, the second outdoor unit 54 according to the magnitude of the cooling load. The second compressor 31 can be driven together with the first compressor 1 to cope with this.

  As shown in FIG. 7, when the first compressor 1 is started, the operating frequency of the first compressor 1 is set to the frequency F1 at the point A, and then when the operating frequency is increased to the point B, the second compression is performed. The frequency setting at which the capacity when the compressor 31 is started and the first compressor 1 is operated by one unit and the capacity when the first compressor 1 and the second compressor 31 are operated is substantially equal. That is, the frequency B1 is set. At this time, the operating frequency of the second compressor 31 is set to the frequency B2. Thereafter, when the operating frequency of the first compressor 1 increases, the speed is increased to point D (maximum operating frequency).

  On the other hand, when both the first compressor 1 and the second compressor 31 are operating, when the operating frequency is lowered, two units are started until the operating frequency reaches point C, and the operating frequency is the point. When C, the frequency setting at which the capacity when operating with the first compressor 1 and the second compressor 31 and the capacity when operating with the first compressor 1 are substantially equal, that is, the first The operating unit frequency of the first compressor 1 is set to C1, and the second compressor 31 is stopped. When the number of compressors increases, the second compressor 31 is started after the operating frequency of the first compressor 1 is decelerated or during deceleration, and when the number of compressors decreases, By increasing the speed of the first compressor 1 after stopping the second compressor 31 or during the stop operation, it is possible to prevent the compressor capacity from becoming excessive during switching.

  FIG. 8 is a flowchart showing a flow of control of each actuator in the shunt controller 52. Based on FIG. 8, the flow of control of each actuator in the diversion controller 52 performed by the control device 52A of the diversion controller 52 will be described. First, the control device 52A acquires the refrigerant temperature Thb (temperature information (TB) from the temperature sensor 210) and the low pressure PL (pressure information from the third low-pressure detection sensor 203) flowing out from the first refrigerant heat exchanger 16 ( Step S201) The controller 52A obtains the difference between the acquired temperature Thb and the saturation temperature Tsat (PL) and sets it as SHb (Step S202).

  The control device 52A calculates the opening degree LEV15 of the second expansion device 15 in accordance with the residual between the SHb and the SHb target value SHbm (step S203). Next, the control device 52A adds the residual to the current control value LEV * and calculates a new control value LEV15 (step S204). Thereafter, the control device 52A determines whether a predetermined time has elapsed (step S205). When the control device 52A determines that the predetermined time has elapsed (step S205; YES), the process returns to step S201, and the same correction calculation is performed. Further, it is assumed that the first expansion device 14 is fully opened during operation.

  FIG. 9 is a flowchart showing a flow of control of the actuator in the indoor unit 53. Based on FIG. 9, the flow of control of the actuator (indoor expansion device 23) in the indoor unit 53 performed by the control device 53A of the indoor unit 53 will be described. First, the controller 53A controls the inlet temperature TH3 of the indoor heat exchanger 22 (temperature information (TL) from the second indoor unit temperature sensor 209) and the outlet temperature TH2 of the indoor heat exchanger 22 (first indoor unit temperature sensor 208). Temperature information (TG)) is acquired (step S301). The control device 53A calculates the difference between the acquired temperature TH2 and temperature TH3 and sets it as SHi (step S302).

  Next, the control device 53A calculates the opening degree LEV23 of the indoor expansion device 23 according to the residual between SH and the target value SHim of SH (step S303). The control device 53A adds the residual to the current control value LEV23 *, and calculates a new control value LEV23 (step S304). Thereafter, the control device 53A determines whether a predetermined time has elapsed (step S305). When the control device 53A determines that the predetermined time has elapsed (step S305; YES), the process returns to step S301, and the same correction calculation is performed.

  Next, the operation when the indoor unit 53 performing the cooling operation and the indoor unit 53 performing the heating operation are mixed and the cooling load is higher than the heating load (hereinafter referred to as cooling main operation) will be described. The gas refrigerant heated to high temperature and high pressure by the first compressor 1 is discharged from the first compressor 1 and flows into the first outdoor heat exchanger 2 through the four-way valve 3. In the first outdoor heat exchanger 2, a part of the gas refrigerant that flows in according to the cooling and heating loads exchanges heat with the outdoor air and condenses and liquefies. The high-pressure refrigerant in a gas-liquid two-phase state that has flowed out of the first outdoor heat exchanger 2 passes through the check valve 5 b and is guided to the first high-pressure pipe 102.

  The high-pressure refrigerant in the gas-liquid two-phase state that is conducted through the first high-pressure pipe 102 flows into the first gas-liquid separator 11 of the shunt controller 52 and is separated into gas refrigerant and liquid cooling. Here, it is assumed that the indoor unit 53a is performing the heating operation, and the indoor unit 53b is performing the cooling operation. The gas refrigerant separated by the first gas-liquid separator 11 reaches the indoor heat exchanger 22a of the indoor unit 53a via the on-off valve 12a and the gas pipe 104a, and heats it by releasing heat to the surroundings. Is condensed and liquefied, becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23a, flows through the liquid pipe 103a, and returns to the shunt controller 52.

  The liquid refrigerant that has returned to the diversion controller 52 is separated by the first gas-liquid separator 11, the supercooling is increased by the first refrigerant heat exchanger 16, and the liquid refrigerant that has been reduced to the intermediate pressure by the first expansion device 14. Merge, flow through the liquid pipe 103b, and flow into the indoor unit 53b. The liquid refrigerant that has flowed into the indoor unit 53b is throttled to a low pressure by the indoor throttle device 23b, takes heat from the surroundings by the indoor heat exchanger 22b, cools, and evaporates and gasifies itself to gas gas 104b and the on-off valve 13b. To the first low-pressure pipe 101.

  The liquid refrigerant that has flowed into the second expansion device 15 is reduced to a low pressure by the second expansion device 15, and the second refrigerant heat exchanger 17 and the first refrigerant heat exchanger 16 remove the liquid refrigerant from the first gas-liquid separator 11. It exchanges heat with the flowing liquid refrigerant to supercool the liquid refrigerant, evaporates and gasifies itself, merges with the gas refrigerant flowing out from the indoor unit 53b, and flows to the first low-pressure pipe 101. The gas refrigerant that passes through the first low-pressure pipe 101 returns to the first compressor 1 via the second gas-liquid separator 36, the check valve 5 a, the four-way valve 3, and the first accumulator 4.

  Here, the operation when the cooling load required for the air conditioner 100 is large will be described. In the operation when the cooling load is large, the flow of the refrigerant discharged from the first compressor 1 is as described above, and therefore will be described in correspondence with the flow of the refrigerant discharged from the second compressor 31. When the cooling load required for the air conditioner 100 is large, not only the first compressor 1 of the first outdoor unit 51 is driven but also the second compressor 31 of the second outdoor unit 54 is driven. It is supposed to be.

  The gas refrigerant driven to high temperature and high pressure by the second compressor 31 is discharged from the second compressor 31 and flows into the second outdoor heat exchanger 32. In the second outdoor heat exchanger 32, the flowing gas refrigerant exchanges heat with outdoor air and condenses and liquefies. Further, by opening the opening / closing device 35, the refrigerant flowing out from the second outdoor heat exchanger 32 is guided to the first high pressure pipe 102 via the second high pressure pipe 106 and condensed in the first outdoor heat exchanger 2. -Merged with the liquefied liquid refrigerant and flows into the diversion controller 52. As described above, the liquid refrigerant that has flowed into the diversion controller 52 cools the area to be cooled at the place where the indoor unit 53b is installed, and after being evaporated and gasified by the indoor heat exchanger 22b, the liquid pipe 104b is conducted. And flows into the second gas-liquid separator 36.

  In the second gas-liquid separator 36, the gas refrigerant and the refrigerating machine oil flowing in the gas refrigerant or along the inner wall surface are separated. Then, the gas refrigerant and the refrigerating machine oil flow out from the second gas-liquid separator 36 and are led to the first outdoor unit 51 side and the second outdoor unit 54 side (second low pressure pipe 105 side). The gas refrigerant containing the refrigerating machine oil that has flowed to the first outdoor unit 51 side returns to the first compressor 1 via the check valve 5 a, the four-way valve 3, and the first accumulator 4. On the other hand, the gas refrigerant including the refrigerating machine oil that flows to the second outdoor unit 54 side returns to the second compressor 31 via the second accumulator 34.

  The control of each actuator during the cooling main operation will be described with a focus on differences from the cooling only operation. The difference is that the first throttle device 14 of the shunt controller 52 and the indoor throttle device 23a of the indoor unit 53a, these two points will be described with reference to FIGS. FIG. 10 is a flowchart showing a control flow of the first expansion device 14 in the flow dividing controller 52. Based on FIG. 10, the control flow of the first throttle device 14 in the flow dividing controller 52 performed by the control device 52A of the flow dividing controller 52 will be described. First, the controller 52A acquires the high pressure PH (pressure information from the third high pressure detection sensor 204) and the intermediate pressure PM (pressure information from the intermediate pressure detection sensor 205) (step S401).

  The control device 52A calculates a residual ΔPHM between the acquired high pressure PH and intermediate pressure PM (step S402). The control device 52A obtains a correction value ΔLEV14 of the opening of the first expansion device 14 according to the difference between the residual ΔPHM and the target value ΔPHM (step S403). Next, the control device 52A adds ΔLEV14 to the current value LEV14 * of the first throttle device 14, and sets a new opening degree LEV14 of the first throttle device 14 (step S404). Thereafter, the controller 52A determines whether a predetermined time has elapsed (step S405). When the control device 52A determines that the predetermined time has elapsed (step S405; YES), the process returns to step S401, and the same correction calculation is performed.

  FIG. 11 is a flowchart showing a flow of control of the actuator of the indoor unit 53a performing the heating operation. Based on FIG. 11, the flow of control of the actuator (indoor expansion device 23a) in the indoor unit 53a performed by the control device 53A of the indoor unit 53a will be described. First, the control device 53A acquires the outlet temperature TH2 of the indoor heat exchanger 22a and obtains information on the high pressure PH of the shunt controller 52 through communication (step S501). The control device 53A obtains the difference between the acquired temperature TH2 and the saturation temperature Tsat (PH) of the high pressure PH obtained through communication and sets it as SCi (step S502).

  Next, the control device 53A calculates the opening degree LEVi of the indoor expansion device 23a according to the residual between SCi and the target value SCim of SCi (step S503). The control device 53A adds the residual to the current control value LEVi * and calculates a new control value LEVi (step S504). Thereafter, the control device 53A determines whether a predetermined time has elapsed (step S505). When the control device 53A determines that a predetermined time has elapsed (step S505; YES), the process returns to step S501 and the same correction calculation is performed.

  Next, an operation when the indoor unit 53 performing the cooling operation and the indoor unit 53 performing the heating operation are mixed and the heating load is higher than the cooling load (hereinafter referred to as heating main operation) will be described. The gas refrigerant that has been heated to high temperature and pressure by the first compressor 1 is discharged from the first compressor 1 and is guided to the first high-pressure pipe 102 via the four-way valve 3 and the check valve 5c. The high-pressure gas refrigerant that conducts through the first high-pressure pipe 102 flows into the first gas-liquid separator 11 of the shunt controller 52. Here, it is assumed that the indoor unit 53a is performing the heating operation, and the indoor unit 53b is performing the cooling operation.

  The gas refrigerant that has flowed into the first gas-liquid separator 11 reaches the indoor heat exchanger 22a via the first on-off valve 12a and the gas pipe 104a, where it releases heat to the surroundings and heats it. The liquid is liquefied, becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23a, flows through the liquid pipe 103a, and returns to the flow dividing controller 52. Part of the liquid refrigerant that has returned to the diversion controller 52 flows through the liquid pipe 103 b and flows into the indoor unit 53 b, and the rest is guided to the first low-pressure pipe 101 via the second expansion device 15.

  The liquid refrigerant flowing into the indoor unit 53b is throttled to a low pressure by the indoor expansion device 23b, takes heat from the surroundings by the indoor heat exchanger 22b, cools, and evaporates and gasifies itself to gas pipe 104b and the second opening / closing. Via the valve 13 b, the gas-liquid two-phase refrigerant that has been throttled to a low pressure by the second throttling device 15 joins and is guided to the first low-pressure pipe 101. The gas-liquid two-phase refrigerant that conducts through the first low-pressure pipe 101 flows into the first outdoor heat exchanger 2 through the second gas-liquid separator 36 and the check valve 5d. The gas-liquid two-phase refrigerant that has flowed into the first outdoor heat exchanger 2 takes heat from the outside air, evaporates and gasifies, and returns to the first compressor 1 via the four-way valve 3 and the first accumulator 4.

  The control of each actuator during the heating-main operation will be described focusing on differences from the cooling-only operation or the cooling-main operation. The difference is that the operating frequency of the first compressor 1 of the first outdoor unit 51 and the rotational speed of the outdoor fan are controlled, and the opening degree of the first throttle device 14 and the second throttle device 15 of the shunt controller 52 is controlled. Therefore, since these are the first throttle device 14 of the flow dividing controller 52 and the indoor throttle device 23a of the indoor unit 53a, these two points will be described with reference to FIG. 5 and FIG.

  First, control of the operating frequency of the first compressor 1 of the first outdoor unit 51 and the rotational speed of the outdoor fan will be described. Control of the operating frequency of the first compressor 1 of the first outdoor unit 51 and the rotational speed of the outdoor fan is performed according to the flowchart of FIG. 5 described above. Here, even if the predetermined frequency is reached, the second When the operation is performed only by the first outdoor unit 51 without issuing an operation command to the outdoor unit 51, and the operation frequency of the first compressor 1 and the rotational speed of the outdoor fan become maximum, the respective corrections are made. Even if the value becomes more than that, it is invalidated and the operation is controlled so that the operation frequency of the first compressor 1 and the rotation speed of the outdoor fan are continued at the maximum.

  FIG. 12 is a flowchart showing a control flow of the second expansion device 15 in the flow dividing controller 52. Based on FIG. 12, the flow of control of the second expansion device 15 in the flow dividing controller 52 performed by the control device 52A of the flow dividing controller 52 will be described. First, the control device 52A acquires the high pressure PH and the intermediate pressure PM (step S601). The control device 52A calculates a residual ΔPHM between the acquired high pressure PH and intermediate pressure PM (step S602). The control device 52A obtains a correction value ΔLEV15 of the opening of the second expansion device 15 according to the difference between the residual ΔPHM and the target value ΔPHM (step S603).

  Next, the control device 52A adds ΔLEV15 to the current value LEV15 * of the second throttle device 15, and sets a new opening degree LEV15 of the second throttle device 15 (step S604). Thereafter, the controller 52A determines whether a predetermined time has elapsed (step S605). When the control device 52A determines that the predetermined time has elapsed (step S605; YES), the process returns to step S601, and the same correction calculation is performed. Further, it is assumed that the first expansion device 14 is fully opened during operation.

  Next, the operation when the all indoor units 53 are in the heating operation (hereinafter referred to as the all heating operation) will be described in correspondence with the flow of the refrigerant. The gas refrigerant that has been heated to high temperature and pressure by the first compressor 1 is discharged from the first compressor 1 and is guided to the first high-pressure pipe 102 via the four-way valve 3 and the check valve 5c. The high-pressure gas refrigerant that conducts through the first high-pressure pipe 102 flows into the first gas-liquid separator 11 of the shunt controller 52. The gas refrigerant flowing into the first gas-liquid separator 11 passes through the first on-off valve 12 (both the first on-off valve 12a and the first on-off valve 12b) and the gas pipe 104 (both the gas pipe 104a and the gas pipe 104b). To the indoor heat exchanger 22, where heat is released to the surroundings to heat it, and it condenses and liquefies itself, becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23, flows through the liquid pipe 103, and flows into the branch flow controller 52. Return to.

  The liquid refrigerant that has returned to the diversion controller 52 is guided to the first low-pressure pipe 101 via the second expansion device 15. The liquid refrigerant that conducts through the first low-pressure pipe 101 flows into the first outdoor heat exchanger 2 through the second gas-liquid separator 36 and the check valve 5d. The liquid refrigerant that has flowed into the first outdoor heat exchanger 2 takes heat from the outside air, evaporates and gasifies, and returns to the first compressor 1 via the four-way valve 3 and the first accumulator 4. In addition, about the control of an actuator, it is good to perform control similar to heating main operation.

  FIG. 13 is a graph for explaining the operating frequency of the first compressor 1. Based on FIG. 13, the operating frequency of the compressor according to the cooling load will be described in detail. In FIG. 13, the horizontal axis represents the total operating frequency of the compressor, and the vertical axis represents the operating frequency divided into the first compressor 1 and the second compressor 31. As shown in FIG. 13, when the first compressor 1 is started, the operating frequency F1 of the first compressor 1 is set, and then the speed is increased to the maximum frequency F4 as necessary. That is, the air conditioning apparatus 100 drives only the first compressor 1 of the first outdoor unit 51 and does not drive the second compressor 31 when the cooling load is small (during heating-main operation or full heating operation). It is doing so.

  Finally, the emergency operation of the air conditioner 100 will be described. In locations where cooling loads are required throughout the year to cool OA equipment such as servers, the OA equipment will not be damaged by the heat generated by the OA equipment when the cooling equipment becomes inoperable. A means for continuing the cooling operation is required. Therefore, the air conditioner 100 has the cooling that the second outdoor unit 54 performs in the first outdoor unit 51 when the first outdoor unit 51 of the first outdoor unit 51 or the second outdoor unit 54 is broken. When the second outdoor unit 54 is in charge of the cooling operation and the second outdoor unit 54 is broken, the first outdoor unit 51 can perform the cooling / heating operation.

  When either the first outdoor unit 51 or the second outdoor unit 54 is broken, a signal (abnormality notification such as an image or sound) is sent to the remote controller 55 to notify the user of the abnormality. You should do it. Further, when the cooling load is high, priorities are given to the indoor units 53 in advance, and the operation is performed in accordance with the operable capacity from the one having a high priority. By doing so, it is possible to prevent heat generation of the OA equipment at a minimum. Due to the configuration and operation of the air conditioner 100 as described above, an inexpensive system, that is, the second outdoor unit 54, can be used even in the summer or when the cooling load becomes larger than the cooling load of the year due to heat generated from the OA equipment or the like. The cooling capacity can be increased and the cooling load can be handled.

  In addition, in this Embodiment 1, although the case where the two outdoor units (the 1st outdoor unit 51 and the 2nd outdoor unit 54) were mounted in the air conditioning apparatus 100 was shown as an example, according to cooling load The number and capacity of the second outdoor units 54 may be changed. Moreover, although the state where the two indoor units 53 are connected in parallel is shown as an example, three or more indoor units 53 may be connected in parallel. Furthermore, although the case where each control device controls the actuator corresponding thereto has been described as an example, any control device may control each actuator as a representative.

Embodiment 2. FIG.
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. Based on FIG. 14, the refrigerant circuit structure of the air conditioning apparatus 200 will be described. The air conditioner 200 is installed in a building such as a building or a condominium, and can simultaneously process a cooling load and a heating load by using a refrigeration cycle that circulates a refrigerant. 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 first outdoor unit 51, a second outdoor unit 54, two switching units 56 (switching unit 56a and switching unit 56b), and two indoor units 53 (indoor unit 53a and indoor unit). 53b). The first outdoor unit 51 and the switching unit 56 (the switching unit 56a and the switching unit 56b) are connected by a high-pressure gas pipe 107 that is a refrigerant pipe, a low-pressure gas pipe 108 that is a refrigerant pipe, and a liquid pipe 109 that is a refrigerant pipe. Yes.

  That is, the outlet of the check valve 5b and the first on-off valve 12 (the first on-off valve 12a and the first on-off valve 12b) are connected via the high-pressure gas pipe 107, and the inlet of the check valve 5a and the second on-off valve 13 (second on-off valve 13a and second on-off valve 13b) are connected via a low-pressure gas pipe 108, and the first outdoor heat exchanger 2 and the first refrigerant heat exchanger 16 (first refrigerant heat exchanger 16a and The first refrigerant heat exchanger 16b) is connected via a liquid pipe 109. In the second outdoor unit 54, the outlet of the second outdoor heat exchanger 32 is connected to the liquid pipe 109 via the second high pressure pipe 106, and the inlet of the second accumulator 34 is connected to the second low pressure pipe 105 and the second low pressure pipe 105. It is connected to the low-pressure gas pipe 108 through the two gas-liquid separator 36. That is, the second outdoor unit 54 is connected and mounted in parallel with the first outdoor unit 51.

  Further, the switching unit 56 and the indoor unit 53 are connected by a liquid pipe 103 (liquid pipe 103a and liquid pipe 103b) and a gas pipe 104 (gas pipe 104a and gas pipe 104b). That is, the outlet of the first refrigerant heat exchanger 16 and the indoor throttle device 23 (the indoor throttle device 23a and the indoor throttle device 23b) are connected via the liquid pipe 103, and the first on-off valve 12 and the second on-off valve. 13 and the indoor heat exchanger 22 (the indoor heat exchanger 22a and the indoor heat exchanger 22b) are connected via a gas pipe 104.

[First outdoor unit 51]
The first outdoor unit 51 includes a first compressor 1, a four-way valve 3, a first outdoor heat exchanger 2, and a first accumulator 4 connected in series, and a three-way valve 6 serving as a flow path switching unit. The four-way valve 3 is connected in parallel. In the first outdoor unit 51, the high pressure gas pipe 107 and the low pressure gas pipe 108 merge and are connected to the four-way valve 3 and the three-way valve 6. Further, in the first outdoor unit 51, a check valve 5b for controlling the flow of the refrigerant by allowing only one of the refrigerants to flow is connected to the low pressure gas pipe 108 connected to the four-way valve 3, and a check valve 5b is provided in all directions. The check valve 5 c is provided in the high pressure gas pipe 107 connected to the valve 3, the check valve 5 c is provided in the low pressure gas pipe 108 connected to the three way valve, and the check valve 5 d is provided in the high pressure gas pipe 107 connected to the three way valve 6.

[Switching unit 56]
The switching unit 56 connects the indoor unit 53a and the indoor unit 53b to the first outdoor unit 51 and the second outdoor unit 54, and each of the indoor unit 53a and the indoor unit 53b is a cooling device or a heating device. It has a function to determine whether. That is, the switching unit 56 functions as a controller that causes the indoor unit 53 to conduct the refrigerant in accordance with the operation status of the indoor unit 53. The switching unit 56 includes the first refrigerant heat exchanger 16, the first on-off valve 12, and the second on-off valve 13.

  The first refrigerant heat exchanger 16 is between the refrigerant that conducts between the second gas-liquid separator 36 and the first on-off valve 12 and the refrigerant that conducts between the indoor expansion device 23 and the liquid pipe 109. Heat exchange. That is, the first refrigerant heat exchanger 16 is provided in the refrigerant pipe between the second gas-liquid separator 36 and the first on-off valve 12 and the liquid pipe 103 between the indoor expansion device 23 and the liquid pipe 109. It is. The first on-off valve 12 is connected to the low-pressure gas pipe 108 and is provided in the refrigerant pipe between the first refrigerant heat exchanger 16 and the indoor heat exchanger 22. Further, the second on-off valve 13 is connected to the high-pressure gas pipe 107 and is provided in the refrigerant pipe connecting the outlet of the check valve 5 b and the indoor heat exchanger 22.

  FIG. 15 is an explanatory diagram for explaining a mechanism for operating an actuator based on information from each detection unit. Based on FIG. 15, each control device (control device 51A, control device 54A, control device 53A, and control device 56A) is an actuator (first compressor 1, second compressor 31, open / close device) based on information from each detection means. 35, a mechanism for operating the first on-off valve 12, the second on-off valve 13, and the indoor throttle device 23) will be briefly described based on communication between the control devices. The control device 56 </ b> A is a control device for each switching unit 56, and has a function of controlling the opening degrees of the first on-off valve 12 and the second on-off valve 13.

  As shown in FIG. 15, the control devices can communicate signals with each other via a control signal line or a radio wave. Hereinafter, communication between the controls will be described focusing on differences from the first embodiment. The control device 56A that has received the operation command information from the control device 53A opens the on-off valve (either the first on-off valve 12 or the second on-off valve 13) corresponding to the indoor unit 53 in which the remote controller 55 is operated. Thereafter, the opening degree of the on-off valve is adjusted in accordance with an instruction from the control device 51A.

  Here, the operation of the air conditioning apparatus 200 will be described. First, the operation of the cooling only operation will be described in correspondence with the refrigerant flow. The gas refrigerant heated to high temperature and high pressure by the first compressor 1 is discharged from the first compressor 1 and flows into the first outdoor heat exchanger 2 through the four-way valve 3. In this 1st outdoor heat exchanger 2, the gas refrigerant which flowed in is heat-exchanged with outdoor air, and is condensed and liquefied. The refrigerant that has flowed out of the first outdoor heat exchanger 2 conducts the liquid pipe 109. The high-pressure liquid refrigerant that conducts the liquid pipe 109 is cooled by the first refrigerant heat exchanger 16 in the switching unit 56 to increase the degree of supercooling, and flows to the liquid pipe 103.

  The liquid refrigerant conducted through the liquid pipe 103 is throttled to a low pressure by the indoor throttle device 23 and flows into the indoor heat exchanger 22. In the indoor heat exchanger 22, the liquid refrigerant that has flowed takes heat from the surrounding outdoor air and evaporates and gasifies. At this time, the cooling target area in the place where the indoor unit 53 is installed is cooled. The refrigerant flowing out of the indoor heat exchanger 22 is conducted through the gas pipe 104, flows into the first refrigerant heat exchanger 16 through the second on-off valve 13, exchanges heat with the high-pressure liquid refrigerant, and the degree of superheat. Is taken to the low-pressure gas pipe 108. The gas refrigerant that passes through the low-pressure gas pipe 108 returns to the first compressor 1 via the second gas-liquid separator 36, the check valve 5 a, the four-way valve 3, the three-way valve 6, and the first accumulator 4.

  Next, the operation when the cooling load required for the air conditioner 200 is large will be described. In the operation when the cooling load is large, the flow of the refrigerant discharged from the first compressor 1 is as described above, and therefore will be described in correspondence with the flow of the refrigerant discharged from the second compressor 31. When the cooling load required for the air conditioner 100 is large, not only the first compressor 1 of the first outdoor unit 51 is driven but also the second compressor 31 of the second outdoor unit 54 is driven. It is supposed to be.

  The gas refrigerant driven to high temperature and high pressure by the second compressor 31 is discharged from the second compressor 31 and flows into the second outdoor heat exchanger 32. In the second outdoor heat exchanger 32, the flowing gas refrigerant exchanges heat with outdoor air and condenses and liquefies. Further, by opening the opening / closing device 35, the refrigerant flowing out from the second outdoor heat exchanger 32 is guided to the liquid pipe 109 via the second high-pressure pipe 106, and condensed and liquefied by the first outdoor heat exchanger 2. The liquid refrigerant merged and flows into the switching unit 56. The high-pressure liquid refrigerant that has flowed into the switching unit 56 is cooled by the first refrigerant heat exchanger 16 in the switching unit 56 to increase the degree of supercooling, and flows to the liquid pipe 103.

  The liquid refrigerant conducted through the liquid pipe 103 is throttled to a low pressure by the indoor throttle device 23 and flows into the indoor heat exchanger 22. In the indoor heat exchanger 22, the liquid refrigerant that has flowed takes heat from the surrounding outdoor air and evaporates and gasifies. At this time, the cooling target area in the place where the indoor unit 53 is installed is cooled. The refrigerant flowing out of the indoor heat exchanger 22 is conducted through the gas pipe 104, flows into the first refrigerant heat exchanger 16 through the second on-off valve 13, exchanges heat with the high-pressure liquid refrigerant, and the degree of superheat. Is taken to the low-pressure gas pipe 108 and flows into the second gas-liquid separator 36.

  In the second gas-liquid separator 36, the gas refrigerant and the refrigerating machine oil flowing in the gas refrigerant or along the inner wall surface are separated. Then, the gas refrigerant and the refrigerating machine oil flow out from the second gas-liquid separator 36 and are led to the first outdoor unit 51 side and the second outdoor unit 54 side (second low pressure pipe 105 side). The gas refrigerant including the refrigerating machine oil flowing toward the first outdoor unit 51 returns to the first compressor 1 via the check valve 5a, the four-way valve 3, the three-way valve 6, and the first accumulator 4. On the other hand, the gas refrigerant including the refrigerating machine oil that flows to the second outdoor unit 54 side returns to the second compressor 31 via the second accumulator 34.

  FIG. 16 is a flowchart showing a flow of control of the operating frequency of the first compressor 1 and the rotational speed of the outdoor fan. Based on FIG. 16, the flow of control of the operating frequency of the first compressor 1 and the rotational speed of the outdoor fan (not shown) of the first outdoor unit 51 will be described. First, the control device 51A acquires the high pressure PD and the low pressure PS (step S701). The control device 51A calculates the residuals between the target values PDm and PSm and the detected values for the acquired high pressure PD and low pressure PS (step S702).

  The control device 51A calculates the correction value ΔF of the operating frequency of the first compressor 1 and the correction value ΔAK of the rotational speed of the outdoor fan according to the residual (step S703). Here, it is assumed that the numerical values a, b, c, and d are constants obtained in advance by a test. Next, the control device 51A adds the correction values ΔF and ΔAK to the current control values F * and AK *, and calculates new control values F and AK (step S704). Thereafter, the control device 51A determines whether a predetermined time has elapsed (step S705). When the control device 51A determines that the predetermined time has elapsed (step S705; YES), the process returns to step S701 and the same correction calculation is performed.

  Next, a method of controlling the operating frequency of the first compressor 1 of the first outdoor unit 51 and the rotational speed of the outdoor fan, and the operating frequency of the second compressor 31 of the second outdoor unit 54 and the rotational speed of the outdoor fan. Will be described. The control device 51A that has received the operation command from the remote controller 55 via the control device 53A first determines the initial value of the operation frequency (F1) of the first compressor 1 according to the outside air temperature, room temperature, and operation capacity. The initial value of the rotation speed (AK1) of the outdoor fan is set. Thereafter, the control device 51A corrects the operating frequency of the first compressor 1 according to the flowchart of FIG. 16, and controls the second compressor 31 when the correction result becomes equal to or higher than the predetermined operating frequency. A command is issued to 54A.

  The control device 54A that has received the command sets the operation frequency (F2) and the rotational speed (AK2) of the outdoor fan that are transmitted together with the operation command of the second compressor 31, and starts the second compressor 31 and the outdoor fan. . Then, in a state where both the first outdoor unit 51 and the second outdoor unit 54 are operating, the operating frequency of the first compressor 1 is corrected according to the flowchart of FIG. 5 described in the first embodiment, and the correction result is predetermined. When the operating frequency is equal to or lower than the operating frequency, the controller 51A issues a command to the controller 54A so as to stop the operation of the second compressor 31. Receiving the command, the control device 54A stops the operation of the second compressor 31 and the outdoor fan.

  FIG. 17 is a graph for explaining the operating frequency of the compressor (both the first compressor 1 and the second compressor 31). The operation frequency of the compressor according to the cooling load will be described in detail based on FIG. In FIG. 17, the horizontal axis indicates the total operating frequency of the compressor, and the vertical axis indicates the operating frequency divided into the first compressor 1 and the second compressor 31. The air conditioner 200 drives only the first compressor 1 of the first outdoor unit 51 when the cooling load is small, and when the cooling load becomes large, the second outdoor unit 54 according to the magnitude of the cooling load. The second compressor 31 can be driven together with the first compressor 1 to cope with this. In addition, the 2nd compressor 31 shall be a constant speed compressor driven with a predetermined power supply frequency.

  As shown in FIG. 17, when the first compressor 1 is started, the operating frequency of the first compressor 1 is set to the frequency F1 at the point A, and then when the operating frequency is increased to the point B, the second compression is performed. The frequency setting at which the capacity when the compressor 31 is started and the first compressor 1 is operated by one unit and the capacity when the first compressor 1 and the second compressor 31 are operated is substantially equal. That is, the frequency B1 is set. Thereafter, when the operating frequency of the first compressor 1 increases, the speed is increased to point D (maximum operating frequency).

  On the other hand, when both the first compressor 1 and the second compressor 31 are operating, when the operating frequency is lowered, two units are started until the operating frequency of the first compressor 1 reaches point C. When the operating frequency reaches point C, the capacity when operating with the first compressor 1 and the second compressor 31 is almost equal to the capacity when operating with the first compressor 1 alone. Frequency setting, that is, the operating frequency of the first compressor 1 is set to C1, and the second compressor 31 is stopped. When the number of compressors increases, the second compressor 31 is started after the operating frequency of the first compressor 1 is decelerated or during deceleration, and when the number of compressors decreases, It is possible to prevent the compressor capacity from becoming excessive during switching by increasing the speed of the first compressor 1 after the second compressor 31 is stopped.

  FIG. 18 is a flowchart showing a flow of control of the actuator in the indoor unit 53. Based on FIG. 18, the flow of control of the actuator (indoor expansion device 23) in the indoor unit 53 performed by the control device 53A of the indoor unit 53 will be described. First, the control device 53A acquires the inlet temperature TH3 and the outlet temperature TH2 of the indoor heat exchanger 22 (step S801). The control device 53A calculates the difference between the acquired temperature TH2 and temperature TH3 and sets it as SHi (step S802).

  Next, the control device 53A calculates the opening degree LEV23 of the indoor expansion device 23 according to the residual between the SHi and the target value SHim of SHi (step S803). The control device 53A adds the residual to the current control value LEV23 *, and calculates a new control value LEV23 (step S804). Thereafter, the control device 53A determines whether a predetermined time has elapsed (step S805). When the control device 53A determines that the predetermined time has elapsed (step S805; YES), the process returns to step S801, and the same correction calculation is performed.

  Next, the operation of the cooling main operation will be described. The gas refrigerant heated to high temperature and high pressure by the first compressor 1 is discharged from the first compressor 1, and a part thereof is led to the high pressure gas pipe 107 via the three-way valve 6 and the check valve 5d, and the rest. Flows into the first outdoor heat exchanger 2 via the four-way valve 3. In the first outdoor heat exchanger 2, a part of the gas refrigerant that flows in according to the cooling and heating loads exchanges heat with the outdoor air and condenses and liquefies. The high-pressure liquid refrigerant that has flowed out of the first outdoor heat exchanger 2 flows into the liquid pipe 109. Here, it is assumed that the indoor unit 53a is performing the heating operation, and the indoor unit 53b is performing the cooling operation.

  The high-temperature and high-pressure gas refrigerant that is conducted through the high-pressure gas pipe 107 reaches the indoor heat exchanger 22a of the indoor unit 53a through the first on-off valve 12a and the gas pipe 104a, where it heats by releasing heat to the surroundings. , Itself condenses and liquefies, becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23a, flows through the liquid pipe 103a, and returns to the liquid pipe 109. The liquid refrigerant that has returned to the liquid pipe 109 merges with the liquid refrigerant that has flowed out of the first outdoor unit 51 and is cooled by the first refrigerant heat exchanger 16 in the switching unit 56b to increase the degree of supercooling, and the liquid pipe 103b. Flowing.

  The liquid refrigerant conducted through the liquid pipe 103b flows into the indoor unit 53b, is throttled to a low pressure by the indoor expansion device 23b, cools by taking heat from the surroundings by the indoor heat exchanger 22b, and evaporates and gasifies itself. The gas flows into the first refrigerant heat exchanger 16 via the gas pipe 104b and the second on-off valve 13b, exchanges heat with the high-pressure liquid refrigerant, and flows to the low-pressure gas pipe 108 after increasing the degree of superheat. The gas refrigerant that passes through the low-pressure gas pipe 108 returns to the first compressor 1 via the second gas-liquid separator 36, the check valve 5 a, the four-way valve 3, and the first accumulator 4.

  Here, the operation when the cooling load required for the air conditioner 200 is large will be described. In the operation when the cooling load is large, the flow of the refrigerant discharged from the first compressor 1 is as described above, and therefore will be described in correspondence with the flow of the refrigerant discharged from the second compressor 31. When the cooling load required for the air conditioner 200 is large, not only the first compressor 1 of the first outdoor unit 51 is driven, but also the second compressor 31 of the second outdoor unit 54 is driven. It is supposed to be.

  The gas refrigerant driven to high temperature and high pressure by the second compressor 31 is discharged from the second compressor 31 and flows into the second outdoor heat exchanger 32. In the second outdoor heat exchanger 32, the flowing gas refrigerant exchanges heat with outdoor air and condenses and liquefies. Further, by opening the opening / closing device 35, the refrigerant flowing out from the second outdoor heat exchanger 32 is guided to the liquid pipe 109 via the second high-pressure pipe 106, and condensed and liquefied by the first outdoor heat exchanger 2. It merges with the liquid refrigerant. Here, it is assumed that the indoor unit 53a is performing the heating operation, and the indoor unit 53b is performing the cooling operation.

  The high-temperature and high-pressure gas refrigerant that is conducted through the high-pressure gas pipe 107 reaches the indoor heat exchanger 22a of the indoor unit 53a through the first on-off valve 12a and the gas pipe 104a, where it heats by releasing heat to the surroundings. , Itself condenses and liquefies, becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23a, flows through the liquid pipe 103a, and returns to the liquid pipe 109. The liquid refrigerant that has returned to the liquid pipe 109 merges with the liquid refrigerant that has flowed out of the first outdoor unit 51 and is cooled by the first refrigerant heat exchanger 16 in the switching unit 56b to increase the degree of supercooling, and the liquid pipe 103b. Flowing.

  The liquid refrigerant conducted through the liquid pipe 103b flows into the indoor unit 53b, is throttled to a low pressure by the indoor expansion device 23b, cools by taking heat from the surroundings by the indoor heat exchanger 22b, and evaporates and gasifies itself. The gas flows into the first refrigerant heat exchanger 16 via the gas pipe 104b and the second on-off valve 13b, exchanges heat with the high-pressure liquid refrigerant, and flows to the low-pressure gas pipe 108 after increasing the degree of superheat. Then, the gas refrigerant that is conducted through the low-pressure gas pipe 108 flows into the second gas-liquid separator 36.

  In the second gas-liquid separator 36, the gas refrigerant and the refrigerating machine oil flowing in the gas refrigerant or along the wall surface are separated. Then, the gas refrigerant and the refrigerating machine oil flow out from the second gas-liquid separator 36 and are led to the first outdoor unit 51 side and the second outdoor unit 54 side (second low pressure pipe 105 side). The gas refrigerant containing the refrigerating machine oil that has flowed to the first outdoor unit 51 side returns to the first compressor 1 via the check valve 5 a, the four-way valve 3, and the first accumulator 4. On the other hand, the gas refrigerant including the refrigerating machine oil that flows to the second outdoor unit 54 side returns to the second compressor 31 via the second accumulator 34.

  The control of each actuator during the cooling main operation will be described focusing on the point different from the case of the all cooling operation, that is, the control of the actuator in the indoor unit 53a that performs the heating operation. FIG. 19 is a flowchart showing a flow of control of the actuator of the indoor unit 53a performing the heating operation. Based on FIG. 19, the flow of control of the actuator (indoor expansion device 23a) in the indoor unit 53a performed by the control device 53A of the indoor unit 53a will be described. First, the control device 53A acquires the outlet temperature TH2 of the indoor heat exchanger 22a, and obtains information on the high pressure PH of the switching unit 56a by communication (step S901).

  The control device 53A obtains the difference between the acquired temperature TH2 and the saturation temperature Tsat (PH) of the high-pressure PH obtained through communication and sets it as SCi (step S902). Next, the control device 53A calculates the opening degree LEVi of the indoor expansion device 23a according to the residual between SCi and the target value SCim of SCi (step S903). The control device 53A adds the residual to the current control value LEVi * and calculates a new control value LEVi (step S904). Thereafter, the control device 53A determines whether a predetermined time has elapsed (step S905). When the control device 53A determines that a predetermined time has elapsed (step S905; YES), the process returns to step S901, and the same correction calculation is performed.

  Next, the heating main operation will be described. The gas refrigerant heated to high temperature and high pressure by the first compressor 1 is discharged from the first compressor 1 and led to the high pressure gas pipe 107 through the four-way valve 3 and the check valve 5b. Here, it is assumed that the indoor unit 53a is performing the heating operation, and the indoor unit 53b is performing the cooling operation. The high-pressure gas refrigerant that is conducted through the high-pressure gas pipe 107 reaches the indoor heat exchanger 22a via the first on-off valve 12a and the gas pipe 104a. Then, the indoor expansion device 23a becomes an intermediate-pressure liquid refrigerant, flows through the liquid pipe 103a, part of the liquid pipe 103b is conducted through the liquid pipe 109, flows into the indoor unit 53b, and the rest flows through the liquid pipe 109. Through the first outdoor unit 51.

  The liquid refrigerant that has flowed to the indoor unit 53b side is first cooled by the first refrigerant heat exchanger 16b in the switching unit 56 to increase the degree of supercooling, and conducts the liquid pipe 103b. The liquid refrigerant conducted through the liquid pipe 103b flows into the indoor unit 53b, is throttled to a low pressure by the indoor expansion device 23b, cools by taking heat from the surroundings by the indoor heat exchanger 22b, and evaporates and gasifies itself. The gas flows into the first refrigerant heat exchanger 16b via the gas pipe 104b and the second on-off valve 13b, exchanges heat with the high-pressure liquid refrigerant, takes a large degree of superheat, and is guided to the low-pressure gas pipe 108.

  The liquid refrigerant that conducts through the liquid pipe 109 flows into the first outdoor heat exchanger 2 of the first outdoor unit 51, takes heat from the outside air, evaporates and gasifies to become a gas refrigerant, and the four-way valve 3 and the first accumulator 4. To return to the first compressor 1. On the other hand, the gas refrigerant that is conducted through the low-pressure gas pipe 108 flows into the first outdoor unit 51, passes through the three-way valve 6 in the first outdoor unit 51, then passes through the four-way valve 3, and flows out from there. The gas refrigerant merges and returns to the first compressor 1 through the first accumulator 4.

  Next, the operation of the heating only operation will be described in correspondence with the refrigerant flow. The gas refrigerant heated to high temperature and high pressure by the first compressor 1 is discharged from the first compressor 1 and partly passes through the four-way valve 3 and the check valve 5b, and the rest is the three-way valve 6 and the check valve. 5d is led to the high-pressure gas pipe 107 and merges. The high-pressure gas refrigerant that is conducted through the high-pressure gas pipe 107 flows into the switching unit 56 (both the switching unit 56a and the switching unit 56b). The gas refrigerant flowing into the switching unit 56 passes through the first on-off valve 12 (both the first on-off valve 12a and the first on-off valve 12b) and the gas pipe 104 (both the gas pipe 104a and the gas pipe 104b). 53.

  The gas refrigerant that has flowed into the indoor unit 53 reaches the indoor heat exchanger 22 where it releases heat to the surroundings and heats it, while it condenses and liquefies itself, and becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23. It flows through the pipe 103 and flows into the liquid pipe 109. The liquid refrigerant that conducts through the liquid pipe 109 flows into the first outdoor heat exchanger 2 of the first outdoor unit 51. The liquid refrigerant that has flowed into the first outdoor heat exchanger 2 takes heat from the outside air, evaporates and gasifies, and returns to the first compressor 1 via the four-way valve 3 and the first accumulator 4. In addition, about the control of an actuator, it is good to perform control similar to heating main operation.

  FIG. 20 is a graph for explaining the operating frequency of the first compressor 1. Based on FIG. 20, the operating frequency of the compressor according to the cooling load will be described in detail. In FIG. 20, the horizontal axis indicates the total operating frequency of the compressor, and the vertical axis indicates the operating frequency divided into the first compressor 1 and the second compressor 31. As shown in FIG. 20, when the first compressor 1 is started, the operating frequency F1 of the first compressor 1 is set, and then the speed is increased to the maximum frequency F4 as necessary. That is, the air conditioner 200 drives only the first compressor 1 of the first outdoor unit 51 and does not drive the second compressor 31 when the cooling load is small (during heating-main operation or full heating operation). It is doing so.

  With the configuration and operation of the air conditioner 200 as described above, the main high-pressure gas pipe 107, low-pressure gas pipe 108, and liquid pipe 109 can be branched to each indoor unit 53 in accordance with the installation position of the indoor unit 53. It becomes. In other words, the air conditioner 200 has two on-off valves (the first on-off valve 12 and the second on-off valve 13) and the first refrigerant heat exchanger even in a space such as a ceiling where the installation space of the indoor unit 53 is limited. By installing the switching unit 56 provided with only 16, it can be installed in a narrow space and the construction becomes easy. Even if the cooling load becomes large in summer or due to heat generation from OA equipment, etc., the cooling capacity can be increased by adding an inexpensive system, that is, the second outdoor unit 54, to reduce the cooling load. It can be processed.

  Furthermore, since the second compressor 31 mounted on the second outdoor unit 54 is a constant speed compressor that operates at the power supply frequency, an expensive component such as an inverter is not required, so that a cheaper system can be obtained. it can. In addition, in this Embodiment 2, although the case where the two outdoor units (the 1st outdoor unit 51 and the 2nd outdoor unit 54) were mounted in the air conditioning apparatus 200 was shown as an example, according to cooling load The number and capacity of the second outdoor units 54 may be changed. Moreover, although the state where the two indoor units 53 are connected in parallel is shown as an example, three or more indoor units 53 may be connected in parallel.

Embodiment 3 FIG.
FIG. 21 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus 300 according to Embodiment 3 of the present invention. Based on FIG. 21, the refrigerant circuit structure of the air conditioning apparatus 300 will be described. The air conditioner 300 is installed in a building such as a building or a condominium, and can simultaneously process a cooling load and a heating load by using a refrigeration cycle that circulates a refrigerant. In the third embodiment, the difference from the first embodiment and the second embodiment described above will be mainly described, and the same parts as those in the first embodiment and the second embodiment are the same. Reference numerals are assigned and explanations are omitted.

  The air conditioner 300 is an embodiment in that the outdoor throttle device 10 is provided in the first outdoor unit 51, the first compressor 21 is provided with an injection port, and the injection circuit 9 is provided. Although different from the air conditioner 100 according to No. 1, the other configurations are basically the same. The first compressor 21 has a structure capable of injecting (injecting) refrigerant supplied from the outside (injection circuit 9) into refrigerant being compressed inside.

  The injection circuit 9 is configured by branching the first high-pressure pipe 102 between the first outdoor heat exchanger 2 and the check valve 5 b and connecting it to the injection port of the first compressor 21. The injection circuit 9 is provided with an injection expansion device 7 and a refrigerant heat exchanger 8 from the upstream side. The outdoor expansion device 10 is installed between the first outdoor heat exchanger 2 and the refrigerant heat exchanger 8, and controls the pressure of the refrigerant that conducts through the low-pressure gas pipe (the first high-pressure pipe 102 during heating operation). It is.

  The injection throttle device 7 functions as a pressure reducing valve or an expansion valve, and expands the refrigerant by reducing the pressure. The injection throttling device 7 is preferably constituted by a device whose opening degree can be variably controlled, for example, an electronic expansion valve. The refrigerant heat exchanger 8 performs heat exchange between the refrigerant flowing through the first high-pressure pipe 102 and the refrigerant flowing through the injection circuit 9. That is, by flowing a part of the refrigerant flowing through the first high-pressure pipe 102 into the injection circuit 9, in the refrigerant heat exchanger 8, the refrigerant flowing through the first high-pressure pipe 102 and the injection circuit 9 flow through the injection throttle device 7. The heat is exchanged with the refrigerant whose pressure has been reduced and reduced, and then injected into the first compressor 21.

  Here, the operation of the air conditioning apparatus 300 will be described. In addition, about operation | movement, suppose that the heating main operation and all heating operation characteristic of the air conditioning apparatus 300 which concern on Embodiment 3 shall be demonstrated. First, the operation of the heating main operation will be described. In this heating-main operation, the following operation is performed as in the first embodiment. That is, the gas refrigerant that has been heated to high temperature and high pressure by the first compressor 21 is discharged from the first compressor 21 and guided to the first high-pressure pipe 102 via the four-way valve 3 and the check valve 5c. The high-pressure gas refrigerant that conducts through the first high-pressure pipe 102 flows into the first gas-liquid separator 11 of the shunt controller 52. Here, it is assumed that the indoor unit 53a is performing the heating operation, and the indoor unit 53b is performing the cooling operation.

  The gas refrigerant that has flowed into the first gas-liquid separator 11 reaches the indoor heat exchanger 22a via the first on-off valve 12a and the gas pipe 104a, where it releases heat to the surroundings and heats it. The liquid is liquefied, becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23a, flows through the liquid pipe 103a, and returns to the flow dividing controller 52. Part of the liquid refrigerant that has returned to the diversion controller 52 flows through the liquid pipe 103 b and flows into the indoor unit 53 b, and the rest is guided to the first low-pressure pipe 101 via the second expansion device 15.

  The liquid refrigerant flowing into the indoor unit 53b is throttled to a low pressure by the indoor expansion device 23b, takes heat from the surroundings by the indoor heat exchanger 22b, cools, and evaporates and gasifies itself to gas pipe 104b and the second opening / closing. Via the valve 13 b, the gas-liquid two-phase refrigerant that has been throttled to a low pressure by the second throttling device 15 joins and is guided to the first low-pressure pipe 101. The gas-liquid two-phase refrigerant that conducts through the first low-pressure pipe 101 flows into the first outdoor heat exchanger 2 through the second gas-liquid separator 36 and the check valve 5d. The gas-liquid two-phase refrigerant that has flowed into the first outdoor heat exchanger 2 takes heat from the outside air, evaporates and gasifies, and returns to the first compressor 21 via the four-way valve 3 and the first accumulator 4.

  Next, the operation of the heating only operation will be described in correspondence with the refrigerant flow. The gas refrigerant heated to high temperature and high pressure by the first compressor 21 is discharged from the first compressor 21 and is guided to the first high-pressure pipe 102 via the four-way valve 3 and the check valve 5c. The high-pressure gas refrigerant that conducts through the first high-pressure pipe 102 flows into the first gas-liquid separator 11 of the shunt controller 52. The gas refrigerant flowing into the first gas-liquid separator 11 passes through the first on-off valve 12 (both the first on-off valve 12a and the first on-off valve 12b) and the gas pipe 104 (both the gas pipe 104a and the gas pipe 104b). To the indoor heat exchanger 22, where heat is released to the surroundings to heat it, and it condenses and liquefies itself, becomes an intermediate-pressure liquid refrigerant in the indoor expansion device 23, flows through the liquid pipe 103, and flows into the branch flow controller 52. Return to.

  The liquid refrigerant that has returned to the diversion controller 52 is guided to the first low-pressure pipe 101 via the second expansion device 15. The liquid refrigerant that conducts through the first low-pressure pipe 101 flows into the first outdoor heat exchanger 2 through the second gas-liquid separator 36 and the check valve 5d. The liquid refrigerant flowing into the first outdoor heat exchanger 2 takes heat from the outside air, evaporates and gasifies, and returns to the first compressor 21 via the four-way valve 3 and the first accumulator 4. In addition, about the control of an actuator, it is good to perform control similar to heating main operation.

  FIG. 22 is a flowchart showing a control flow of the outdoor expansion device 10. Based on FIG. 22, the flow of control of the outdoor expansion device 10 when the outside air is particularly low will be described. When the outside air is particularly low, the injection throttle device 7 is opened and the outdoor throttle device 10 is controlled to be throttled. That is, when the outside air is particularly low, the air conditioner 300 causes the refrigerant to be conducted to the injection circuit 9 and injects the refrigerant into the compression process of the first compressor 21. The case where the control device 51A controls the outdoor expansion device 10 will be described as an example.

  First, the control device 51A acquires the low pressure PL (step S1001). Control device 51A calculates residual ΔPLm between PL and PL target value PLm (step S1002). Next, the control device 51A obtains a correction value ΔLEV10 of the opening degree of the outdoor expansion device 10 according to the residual ΔPLm (step S1003). The control device 51A adds ΔLEV10 to the current opening degree value LEV10 * of the outdoor throttle device 10 to set a new opening degree LEV10 of the outdoor throttle device 10 (step S1004). Thereafter, the control device 51A determines whether a predetermined time has elapsed (step S1005). When the control device 51A determines that a predetermined time has elapsed (step S1005; YES), the process returns to step S1001 and the same correction calculation is performed.

  FIG. 23 is a flowchart showing the flow of control of the injection throttle device 7. Based on FIG. 23, the flow of control of the injection throttle device 7 when the outside air is particularly low will be described. The case where the control device 51A controls the injection throttle device 10 will be described as an example. First, the control device 51A obtains the discharge temperature THd of the refrigerant discharged from the first compressor 21 and obtains the high pressure PD (step S1101). The control device 51A calculates the difference between the saturation temperature Tsat (PD) of THd and PD and sets it as SHd (step S1102).

  The control device 51A calculates the opening degree LEV7 of the injection throttle device 7 according to the residual between SHd and the target value SHdm of SHd (step S1103). Next, the control device 51A adds the residual to the current control value LEV7 * and calculates a new control value LEV7 (step S1104). Thereafter, the control device 51A determines whether a predetermined time has elapsed (step S1105). When the control device 51A determines that the predetermined time has elapsed (step S1105; YES), the process returns to step S1101, and the same correction calculation is performed.

  In general heat pump heating, when the outside air temperature is low, the evaporation temperature decreases as the outside air temperature decreases, and the density of the refrigerant sucked into the compressor decreases, so that the flow rate of the refrigerant discharged from the compressor decreases. , Heating capacity is reduced. However, in the air conditioning apparatus 300 according to Embodiment 3, the above control makes the temperature of the refrigerant evaporated in the indoor unit 53b performing the cooling operation appropriate, while maintaining the pressure at which the refrigerant can flow from the injection port. By controlling the refrigerant pressure in the low-pressure gas pipe (the first high-pressure pipe 102 during heating operation), the decrease in the density of the refrigerant sucked into the first compressor 21 is compensated by the injection refrigerant at the time of low outside air. It is possible to prevent the circulation amount from decreasing even with low outside air. For this reason, it can be set as the system whose heating capability does not fall even at the time of the low outside air.

  In addition, as shown in FIG. 24, the 1st compressor 1 mounted in the 1st outdoor unit 51 is divided | segmented into the high stage side compressor 1b and the low stage side compressor 1a, and the discharge side of the low stage side compressor 1a Even when the injection circuit 9 is connected between the high-stage compressor 1b and the suction side of the high-stage compressor 1b and the full heating operation and the heating main operation are performed in the low outside air, the same effect as the air conditioner 300 is obtained. Further, since the high-stage compressor 1b and the low-stage compressor 1a do not have a specific function such as an injection port, by using the same as a standard compressor, parts can be standardized and costs can be reduced.

  Due to the configuration and operation of the air conditioner 300 as described above, an inexpensive system, that is, the second outdoor unit 54, can be used even in the summer or when the cooling load becomes larger than the cooling load of the year due to the heat generated from the OA equipment. The cooling capacity can be increased and the cooling load can be handled. In addition, by providing the injection circuit 9, it is possible to prevent the refrigerant circulation rate from decreasing even in low outside air even in low outside air, so that the heating capacity can be prevented from being lowered.

  In addition, in this Embodiment 3, although the case where the two outdoor units (the 1st outdoor unit 51 and the 2nd outdoor unit 54) were mounted in the air conditioning apparatus 300 was shown as an example, according to cooling load The number and capacity of the second outdoor units 54 may be changed. Moreover, although the state where the two indoor units 53 are connected in parallel is shown as an example, three or more indoor units 53 may be connected in parallel. Furthermore, although the case where each control device controls the actuator corresponding thereto has been described as an example, any control device may control each actuator as a representative.

3 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus according to Embodiment 1. FIG. It is explanatory drawing for demonstrating the mechanism which operates an actuator based on the information from each detection means. It is a timing chart for demonstrating the flow of the communication transmitted / received between control apparatuses. It is a schematic structure figure showing an example of the structure of the 2nd gas-liquid separator. It is a schematic structure figure showing another example of the structure of the 2nd gas liquid separator. It is a flowchart which shows the flow of control of the operating frequency of a 1st compressor, and the rotation speed of an outdoor fan. It is a graph for demonstrating the operating frequency of a compressor. It is a flowchart which shows the flow of control of each actuator in a shunt controller. It is a flowchart which shows the flow of control of the actuator in an indoor unit. It is a flowchart which shows the flow of control of the 1st expansion device in a shunt controller. It is a flowchart which shows the flow of control of the actuator of the indoor unit which is performing heating operation. It is a flowchart which shows the flow of control of the 2nd expansion apparatus in a shunt controller. It is a graph for demonstrating the operating frequency of a 1st compressor. 6 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus according to Embodiment 2. FIG. It is explanatory drawing for demonstrating the mechanism which operates an actuator based on the information from each detection means. It is a flowchart which shows the flow of control of the operating frequency of a 1st compressor, and the rotation speed of an outdoor fan. It is a graph for demonstrating the operating frequency of a compressor. It is a flowchart which shows the flow of control of the actuator in an indoor unit. It is a flowchart which shows the flow of control of the actuator of the indoor unit which is performing heating operation. It is a graph for demonstrating the operating frequency of a 1st compressor. 6 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus according to Embodiment 3. FIG. It is a flowchart which shows the flow of control of an outdoor aperture device. It is a flowchart which shows the flow of control of an injection throttle apparatus. FIG. 5 is a refrigerant circuit diagram illustrating another refrigerant circuit configuration of an air-conditioning apparatus according to Embodiment 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 1a Low stage side compressor, 1b High stage side compressor, 2 First outdoor heat exchanger, 3 Four way valve, 4 First accumulator, 5a Check valve, 5b Check valve, 5c Check valve, 5d check valve, 6 three-way valve, 7 injection throttling device, 8 refrigerant heat exchanger, 9 injection circuit, 10 outdoor throttling device, 11 first gas-liquid separator, 12 first on-off valve, 12a first on-off valve, 12b 1st on-off valve, 13 2nd on-off valve, 13a 2nd on-off valve, 13b 2nd on-off valve, 14 1st expansion device, 15 2nd expansion device, 16 1st refrigerant | coolant heat exchanger, 16a 1st refrigerant | coolant heat exchanger 16b First refrigerant heat exchanger, 17 Second refrigerant heat exchanger, 21 First compressor, 22 Indoor heat exchanger, 22a Indoor heat exchanger, 22b Indoor heat exchanger, 23 Indoor expansion device, 23a Indoor expansion device , 23b Indoor aperture Equipment, 31 2nd compressor, 32 2nd outdoor heat exchanger, 34 2nd accumulator, 35 switchgear, 36 2nd gas-liquid separator, 41 fuselage, 42 inflow pipe, 43a outflow pipe, 43b outflow pipe, 44a Oil hole, 44b oil return hole, 45 inflow part, 46a outflow part, 46b outflow part, 47 fuselage, 51 outdoor unit, 51A control device, 52 diversion controller, 52A control device, 53 indoor unit, 53A control device, 53a indoor unit 53b indoor unit, 54 outdoor unit, 54A control device, 55 remote controller, 56 switching unit, 56A control device, 56a switching unit, 56b switching unit, 100 air conditioner, 101 first low pressure pipe, 102 first high pressure pipe, 103 Liquid piping, 103a Liquid piping, 103b Liquid piping, 104 Gas piping, 04a gas pipe, 104b gas pipe, 105 second low pressure pipe, 106 second high pressure pipe, 107 high pressure gas pipe, 108 low pressure gas pipe, 109 liquid pipe, 110 bypass pipe, 111 connection pipe, 112 connection pipe, 130 first connection Pipe, 131 Second connection pipe, 200 Air conditioner, 201 High pressure sensor, 202 Low pressure sensor, 203 Low pressure sensor, 204 High pressure sensor, 205 Intermediate pressure sensor, 206 High pressure sensor, 207 Low pressure sensor, 208 Indoor unit temperature sensor, 208a Indoor unit temperature sensor, 208b Indoor unit temperature sensor, 209 Indoor unit temperature sensor, 209a Indoor unit temperature sensor, 209b Indoor unit temperature sensor, 210 Temperature sensor, 300 Air conditioning apparatus.

Claims (6)

At least one indoor unit equipped with an indoor heat exchanger and an indoor expansion device;
A first outdoor unit connected to the indoor unit and mounted with a first compressor, a flow path switching means and a first outdoor heat exchanger;
A controller that is connected between the indoor unit and the first outdoor unit, and conducts refrigerant to the indoor unit in accordance with an operation status of the indoor unit;
A second for cooling operation, which is connected between the first outdoor unit and the controller so as to be in parallel with the first outdoor unit, and is equipped with a second compressor, a second outdoor heat exchanger, and a throttle device. An outdoor unit ,
A first gas-liquid separator provided in the controller and installed at a position downstream of the first outdoor unit and the second outdoor unit;
Provided between the controller and the first outdoor unit and the second outdoor unit, and installed at a position downstream of the controller and upstream of the first outdoor unit and the second outdoor unit. A second gas-liquid separator,
The second outdoor unit is
Drive is controlled according to the cooling load in the indoor unit, to compensate for the cooling operation in the first outdoor unit,
The second compressor is
When the operating frequency of the first compressor is increased to a predetermined frequency, it is started,
The operating frequency of the first compressor is
The capacity when operating by itself is set to be approximately equal to the capacity when operating by itself and the second compressor.
An air conditioner characterized by that. The controller is
It is comprised with the shunt controller which controls the flow of a refrigerant | coolant according to the driving | running state of the said indoor unit, or the switching unit which switches the flow of a refrigerant | coolant according to the driving | running state of the said indoor unit. Air conditioner. The second compressor is
The air conditioner according to claim 1 or 2 , wherein a constant speed operation is performed at a predetermined power supply frequency. The first compressor has an injection port,
An injection throttle device and a refrigerant heat exchanger are provided in an injection circuit for branching a refrigerant pipe between the controller and the upstream side of the first outdoor heat exchanger during heating operation, and connecting to an injection port of the first compressor. The air according to any one of claims 1 to 3 , wherein an outdoor expansion device is provided between the upstream side of the first outdoor heat exchanger and the refrigerant heat exchanger during heating operation. Harmony device. The first compressor is composed of a high-stage compressor and a low-stage compressor,
A refrigerant pipe branched between the suction side of the high-stage compressor and the discharge side of the low-stage compressor between the controller and the upstream side of the first outdoor heat exchanger during heating operation The air conditioner according to any one of claims 1 to 3 , wherein the air conditioner is connected. At the time of failure of the first outdoor unit,
The second outdoor unit is
The air-conditioning apparatus according to any one of claims 1 to 5 , wherein the air-conditioning apparatus performs a cooling operation performed by the first outdoor unit.

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