WO2017179166A1 - Air-conditioning device - Google Patents

Abstract

First throttle devices (212, 213) mounted in a first branch unit (210) and a second throttle device (223) mounted in a second branch unit (220) are provided downstream from indoor-side throttle devices (311) in the flow of refrigerant during an operation in which refrigerant discharged from a compressor is supplied to heat exchangers mounted in indoor units (310), and an intermediate pressure of a refrigeration cycle is controlled by adjusting the degree of opening of the first throttle devices (212, 213) and second throttle device (223).

Description

Air conditioner

The present invention relates to an air conditioner equipped with a refrigeration cycle and capable of providing an air conditioning load.

Conventionally, air conditioners that are equipped with a refrigeration cycle and can provide an air conditioning load have been proposed. As such, for example, a compressor, a heat exchanger, a throttling device, an indoor heat exchanger, and an accumulator as described in Patent Documents 1 and 2 are connected to simultaneously provide a cooling load and a heating load. There is an air conditioning and hot water supply complex system that can do.

Japanese Patent No. 2534926 Japanese Patent No. 5106536

The air conditioner described in Patent Document 1 or Patent Document 2 enables a configuration in which a plurality of indoor units can be connected by connecting one parent branch unit and one or two child branch units. Yes.

Normally, there are restrictions on the number of branch units connected to an air conditioner. Therefore, depending on the arrangement of the indoor units, the handling of the refrigerant pipe length from the branch unit to the indoor unit may be complicated. Further, it may be necessary to extend the refrigerant pipe from the branch unit to the indoor unit. When the handling of the refrigerant pipes becomes complicated or the refrigerant pipes are extended, there is a problem that it leads to an increase in cost required for construction and an increase in the amount of additional charge refrigerant.

The present invention has been made to solve the above-described problems, and provides an air conditioner that can improve the degree of freedom in handling refrigerant piping from the branch unit to the indoor unit and reduce the amount of additional charged refrigerant. It is intended to provide.

An air conditioner according to the present invention includes at least one heat source unit on which a compressor and a first heat exchanger are mounted, and at least one indoor unit on which a second heat exchanger and an indoor expansion device are mounted. A first branch unit connected between the heat source unit and the indoor unit and mounted with at least two first expansion devices; connected between the first branch unit and the indoor unit; and at least 1 And a second branch unit on which two second expansion devices are mounted. A refrigeration cycle is formed by connecting the compressor, the first heat exchanger, the indoor expansion device, and the second heat exchanger. The first throttle device and the second throttle device are arranged below the indoor side throttle device in the refrigerant flow during operation of supplying the refrigerant discharged from the compressor to the second heat exchanger. It provided on the side, by adjusting the opening degree of the first throttle device and said second throttle device, which controls the intermediate pressure of the refrigeration cycle.

According to the air conditioner of the present invention, the intermediate pressure of the refrigeration cycle is controlled by adjusting the opening degrees of the first throttle device and the second throttle device, so that a plurality of branch units are connected to the heat source unit. It is possible to reduce the construction cost and the additional refrigerant charging amount.

It is a refrigerant circuit figure showing roughly an example of the refrigerant circuit composition of the air harmony device concerning an embodiment of the invention. It is a control block diagram which shows the electrical structure of the air conditioning apparatus which concerns on embodiment of this invention. It is the schematic diagram which showed the trend of the refrigerant | coolant pressure in the air conditioning apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of the control processing in the parent branch unit control means of the parent branch unit of the air conditioning apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of the control processing in the child branch unit control means of the child branch unit of the air conditioning apparatus which concerns on embodiment of this invention. It is the schematic construction drawing which showed roughly an example of the construction drawing of the air conditioning apparatus which concerns on embodiment of this invention which connected the some child branch unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one. Further, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and this is common throughout the entire specification. Furthermore, the forms of the constituent elements shown in the entire specification are merely examples, and are not limited to these descriptions.

FIG. 1 is a refrigerant circuit diagram schematically showing an example of a refrigerant circuit configuration of the air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Hereinafter, based on FIG. 1, the structure of the air conditioning apparatus 100 is demonstrated.

The air conditioner 100 is installed in, for example, a building, a condominium, or a hotel, and can supply a cooling load and a heating load simultaneously by using a refrigeration cycle (heat pump) that circulates refrigerant.
It should be noted that the number of connected units constituting the air conditioner 100 is not limited to the number shown in FIG.

<Configuration of Air Conditioner 100>
The air conditioner 100 is configured by connecting a heat source unit 110, a parent branch unit 210, a child branch unit 220, and an indoor unit 310. Among these, the indoor unit 310 is connected in parallel to the heat source unit 110.

The heat source unit 110 and the parent branch unit 210 are connected by two refrigerant pipes (a high pressure main pipe 001 and a low pressure main pipe 002).
The parent branch unit 210 and the child branch unit 220 are connected by three refrigerant pipes (liquid pipe 003, gas pipe 004, and low pressure pipe 005).
The parent branch unit 210 and the indoor unit 310, and the child branch unit 220 and the indoor unit 310 are connected by two refrigerant pipes (a liquid refrigerant pipe 010 and a gas refrigerant pipe 009).
The heat source unit 110 communicates with the indoor unit 310 via the parent branch unit 210 (or the parent branch unit 210 and the child branch unit 220).

[Heat source unit 110]
The heat source unit 110 has a function of supplying hot or cold to the indoor unit 310 via the parent branch unit 210 or the parent branch unit 210 and the child branch unit 220.
The heat source unit 110 mainly includes a compressor 111, a flow path switching device 112, a heat exchanger 113, a check valve 114, and an accumulator (liquid reservoir container) 115. These are sequentially connected to constitute a part of the refrigerant circuit.
In addition, what is necessary is just to comprise the selection of the refrigerant circuit components used inside a unit, and a refrigerant circuit by the use of the heat source unit 110. FIG.

The compressor 111 is not particularly limited as long as it sucks the refrigerant and compresses the refrigerant to bring it into a high temperature / high pressure state. For example, the compressor 111 can be configured using various types such as reciprocating, rotary, scroll, or screw. The compressor 111 may be of a type that can be variably controlled by an inverter.

The flow path switching device 112 is constituted by, for example, a four-way valve or the like, and switches the flow of the refrigerant according to a required operation mode. The flow path switching device 112 may be configured by combining two-way valves or three-way valves.

The heat exchanger 113 has a role of mainly absorbing heat from a heat source (eg, air, water, brine, etc.) or radiating heat to the heat source. The type of the heat exchanger 113 may be selected according to the heat source to be used. If the air is a heat source, the type is a pneumatic heat exchanger. If the water or brine is a heat source, the heat exchanger 113 is configured by a water heat exchanger. do it. When the heat exchanger 113 is an air heat exchanger, a heat source side blower such as a fan may be provided around the heat exchanger 113. When the heat exchanger 113 is a water heat exchanger, a pump for circulating water may be provided in the water side circuit.
The heat exchanger 113 corresponds to the “first heat exchanger” of the present invention.

The accumulator 115 may be any one provided on the suction side of the compressor 111 and capable of storing excess refrigerant. The accumulator 115 is not essential for the refrigerant circuit configuration of the air conditioner 100.

The check valve 114 provided in the heat source unit 110 includes four check valves 114 (the check valve 114a to the check valve 114d).
In the heat source unit 110, two refrigerant pipes (refrigerant pipe 011 and refrigerant pipe 012) for connecting the high-pressure main pipe 001 and the low-pressure main pipe 002 are provided. The refrigerant pipe 011 connects the low-pressure main pipe 002 on the upstream side of the check valve 114a and the high-pressure main pipe 001 on the upstream side of the check valve 114d. The refrigerant pipe 012 connects the low-pressure main pipe 002 on the downstream side of the check valve 114a and the high-pressure main pipe 001 on the downstream side of the check valve 114d.

The check valve 114a is provided in the low-pressure main pipe 002 between the flow path switching device 112 and the parent branch unit 210, and allows the refrigerant to flow only in the direction from the parent branch unit 210 to the heat source unit 110. Yes.
The check valve 114d is provided in the high-pressure main pipe 001 between the heat exchanger 113 and the parent branch unit 210, and allows the refrigerant to flow only in the direction from the heat source unit 110 to the parent branch unit 210. .

The check valve 114b is provided in the refrigerant pipe 011 and allows the refrigerant to flow only from the low-pressure main pipe 002 to the heat exchanger 113 via the refrigerant pipe 011.
The check valve 114c is provided in the refrigerant pipe 012 and allows the refrigerant to flow only in the direction of the high-pressure main pipe 001 from the flow path switching device 112 via the refrigerant pipe 012.

Therefore, the indoor unit 310 requires by providing the high-pressure main pipe 001, the low-pressure main pipe 002, the refrigerant pipe 011, the refrigerant pipe 012, the check valve 114a, the check valve 114b, the check valve 114c, and the check valve 114d. Regardless of the operation, the flow of the refrigerant flowing from the heat source unit 110 into the parent branch unit 210 can be in a certain direction.
These are not essential for the refrigerant circuit configuration of the air conditioner 100.

The heat source unit 110 includes a high pressure sensor 116 and a low pressure sensor 117. The high pressure sensor 116 is provided on the discharge side of the compressor 111 and detects the discharge pressure of the refrigerant discharged from the compressor 111. The low pressure sensor 117 is provided on the suction side of the compressor 111 and detects the suction pressure of the refrigerant sucked into the compressor 111. The refrigerant pressure information detected by the high pressure sensor 116 and the low pressure sensor 117 is sent to the heat source unit control means 410 mounted on the heat source unit 110.

Although not shown, if necessary, a temperature sensor that detects the refrigerant discharge temperature, a temperature sensor that detects the refrigerant suction temperature, a temperature sensor that detects the air conditioning refrigerant suction temperature, and the heat exchanger 113 flows out. You may provide the temperature sensor which detects the temperature of the refrigerant | coolant to enter, the temperature sensor which detects the external temperature taken in into the heat-source unit 110, etc. The temperature information of the refrigerant and air detected by these temperature sensors is also sent to the heat source unit control means 410.

[Parent branch unit 210]
The parent branch unit 210 has a function of supplying the indoor unit 310 and the child branch unit 220 with the heat or cold supplied from the heat source unit 110.
The parent branch unit 210 mainly includes a gas-liquid separator 211, a flow path switching device 214, a throttle device 212, and a throttle device 213.
In the main branch unit 210, the liquid pipe 003a, the gas pipe 004a, and the low pressure pipe 005a can be connected to the sub branch unit 220.
The parent branch unit 210 corresponds to the “first branch unit” of the present invention.

The liquid pipe 003 a is connected to the liquid distribution pipe 006 between the parent branch unit 210 and the child branch unit 220. A liquid pipe 003b and a liquid pipe 003c are connected to the liquid pipe 006, and the refrigerant flowing through the liquid pipe 003a through the liquid pipe 006 is divided into the liquid pipe 003b and the liquid pipe 003c. The liquid pipe 003b and the liquid pipe 003c are connected to the child branch unit 220. FIG. 1 shows an example in which only the liquid pipe 003 c is connected to the child branch unit 220.

The gas pipe 004 a is connected to the gas distribution pipe 007 between the parent branch unit 210 and the child branch unit 220. A gas pipe 004b and a gas pipe 004c are connected to the gas distribution pipe 007, and the refrigerant flowing through the gas pipe 004a by the gas distribution pipe 007 is divided into the gas pipe 004b and the gas pipe 004c. The gas pipe 004 b and the gas pipe 004 c are connected to the child branch unit 220. FIG. 1 shows an example in which only the gas pipe 004c is connected to the child branch unit 220.

The low pressure pipe 005a is connected to the low pressure junction pipe 008 between the parent branch unit 210 and the child branch unit 220. A low pressure pipe 005b and a low pressure pipe 005c are connected to the low pressure joining pipe 008, and the refrigerant flowing through the low pressure pipe 005b and the low pressure pipe 005c is joined by the low pressure joining pipe 008. The low pressure pipe 005 b and the low pressure pipe 005 c are connected to the child branch unit 220. FIG. 1 shows an example in which only the low-pressure pipe 005c is connected to the child branch unit 220.

The flow path switching device 214 switches the flow of refrigerant supplied to the indoor unit 310. By switching the refrigerant flow path by this flow path switching device 214, the indoor unit 310 connected to the parent branch unit 210 can simultaneously perform cooling and heating. The flow path switching device 214 is composed of, for example, a three-way valve, and one is connected to the low-pressure main pipe 002, the other is connected to the gas-liquid separator 211, and the other is connected to the indoor heat exchanger 312 of the indoor unit 310. It comes to connect.

In addition, the flow path switching device 214 is provided with a number (two in this case) corresponding to the number of indoor units 310 connected to the parent branch unit 210. Of the flow path switching devices 214, the one connected to the indoor unit 310a is illustrated as the flow path switching device 214a, and the one connected to the indoor unit 310b is illustrated as the flow path switching device 214b.

The gas-liquid separator 211 is connected to the high-pressure main pipe 001 and to the inflow / outflow side of the indoor unit 310. The gas-liquid separator 211 has a function of separating the inflowing refrigerant into a gas refrigerant and a liquid refrigerant. The gas-liquid separator 211 is mounted when the refrigerant pipe between the heat source unit 110 and the parent branch unit 210 is a two-pipe type.

The expansion device 212 is provided between the gas-liquid separator 211 and the indoor expansion device 311 and has a function as a pressure reducing valve or an expansion valve, and expands the refrigerant by reducing the pressure.
The expansion device 213 is provided in a connection pipe connecting the low-pressure main pipe 002 and the piping between the expansion device 212 and the indoor expansion device 311, and has a function as a pressure reducing valve or an expansion valve, and decompresses the refrigerant. And expand.
The throttling device 212 and the throttling device 213 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 diaphragm device 212 and the diaphragm device 213 correspond to the “first diaphragm device” of the present invention.

The parent branch unit 210 includes a high pressure sensor 215 and an intermediate pressure sensor 216. The high-pressure sensor 215 is provided between the gas-liquid separator 211 and the expansion device 212 and detects the pressure of the refrigerant that has flowed out of the gas-liquid separator 211. The intermediate pressure sensor 216 is provided on the downstream side of the expansion device 212 and detects the pressure of the refrigerant flowing out of the expansion device 212. The refrigerant pressure information detected by the high pressure sensor 215 and the intermediate pressure sensor 216 is sent to the parent branch unit control means 420 a mounted on the parent branch unit 210.

The pressure information sent to the parent branch unit control means 420a is the difference between the high pressure sensor 215 and the intermediate pressure sensor 216 in order to supply the refrigerant appropriately to the indoor unit 310 for heating operation or the indoor unit 310 for cooling operation. Hereinafter, it is used to sense the intermediate differential pressure). Note that the value of the high pressure sensor 215 may be replaced with the value of the high pressure sensor 116 of the heat source unit 110 as necessary.

The parent branch unit 210 includes a temperature sensor 217. The temperature sensor 217 is provided in a pipe that communicates from the parent branch unit 210 to the indoor unit 310, and detects the refrigerant temperature that is used to calculate the degree of supercooling of the refrigerant. That is, the degree of refrigerant supercooling can be detected by the temperature sensor 217 and the intermediate pressure sensor 216. Here, if the degree of supercooling of the refrigerant is positive, the refrigerant is in a liquid refrigerant state, which means that the distribution of the liquid refrigerant to the indoor unit 310 and the child branch unit 220 that perform the cooling operation does not deteriorate. Conversely, if the degree of supercooling is 0 ° C., it means that the refrigerant is in a two-phase refrigerant state and the refrigerant distribution is deteriorated. Therefore, it is possible to detect refrigerant distribution by calculating the degree of supercooling of the refrigerant.

[Sub-branch unit 220]
The child branch unit 220 has a function of supplying the indoor unit 310 with hot or cold supplied from the heat source unit 110.
The child branch unit 220 is mainly composed of a flow path switching device 224 and an expansion device 223.
The child branch unit 220 corresponds to the “second branch unit” of the present invention.

The flow path switching device 224 switches the flow of the refrigerant supplied to the indoor unit 310. By switching the refrigerant flow path with this flow path switching device 224, the indoor unit 310 connected to the child branch unit 220 can simultaneously perform cooling and heating. The flow path switching device 224 is composed of, for example, a three-way valve, and one is connected to the low-pressure pipe 005c, the other is connected to the gas pipe 004c, and the other is connected to the indoor heat exchanger 312 of the indoor unit 310. It is like that.

Note that the flow path switching device 224 is provided in a number (two in this case) corresponding to the number of indoor units 310 connected to the child branch unit 220. Of the flow path switching devices 224, those connected to the indoor unit 310c are illustrated as flow path switching devices 224a, and those connected to the indoor unit 310d are illustrated as flow path switching devices 224b.

The throttle device 223 is provided in a connection pipe connecting the low pressure pipe 005c and the pipe between the liquid pipe 003c and the indoor side throttle device 311. The throttle device 223 functions as a pressure reducing valve or an expansion valve, and decompresses the refrigerant. And expand. The throttling device 223 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 diaphragm device 223 corresponds to the “second diaphragm device” of the present invention.

The child branch unit includes an intermediate pressure sensor 226. The intermediate pressure sensor 226 is provided in the liquid pipe 003a and detects the pressure of the refrigerant flowing through the liquid pipe 003a. The refrigerant pressure information detected by the intermediate pressure sensor 226 is sent to the child branch unit control means 420b mounted on the child branch unit 220.

The pressure information sent to the sub-branch unit control means 420b uses the differential pressure between the high-pressure sensor 215 and the intermediate-pressure sensor 226 to appropriately supply the refrigerant to the indoor unit 310 for heating operation or the indoor unit 310 for cooling operation. Hereinafter, it is used to sense the intermediate differential pressure). Note that the value of the high pressure sensor 215 may be replaced with the value of the high pressure sensor 116 of the heat source unit 110 as necessary.

Further, the child branch unit 220 includes a temperature sensor 227. The temperature sensor 227 is provided in the liquid pipe 003a and detects the refrigerant temperature used for calculating the degree of supercooling of the refrigerant. That is, the degree of refrigerant supercooling can be detected by the temperature sensor 227 and the intermediate pressure sensor 226. Here, if the degree of supercooling of the refrigerant is positive, the refrigerant is in a liquid refrigerant state, which means that the distribution of the liquid refrigerant to the indoor unit 310 that is performing the cooling operation does not deteriorate. Conversely, if the degree of supercooling is 0 ° C., it means that the refrigerant is in a two-phase refrigerant state and the refrigerant distribution is deteriorated. Therefore, it is possible to detect refrigerant distribution by calculating the degree of supercooling of the refrigerant.

[Indoor unit 310]
The indoor unit 310 has a function of receiving heating or cooling supply from the heat source unit 110 and taking charge of heating load or refrigerant load.
The indoor unit 310 mainly includes an indoor expansion device 311 and an indoor heat exchanger (load-side heat exchanger) 312. These are sequentially connected by piping to constitute a part of the refrigerant circuit.
FIG. 1 shows an example in which four indoor units 310 are connected. Of the four units, the indoor unit 310 a and the indoor unit 310 are connected in parallel to the parent branch unit 210. Of the four units, the indoor unit 310 c and the indoor unit 310 d are connected in parallel to the child branch unit 220.

Note that the number of indoor units 310 connected is not limited to the number shown, and five or more indoor units 310 may be similarly connected. The indoor unit 310 may be provided with an indoor fan such as a fan for supplying air to the indoor heat exchanger 312 in the vicinity of the indoor heat exchanger 312. Furthermore, the indoor unit 310 is an example of a load side unit.

The indoor expansion device 311 is provided in the liquid pipe 003a in the indoor unit 310, has a function as a pressure reducing valve or an expansion valve, and expands the refrigerant by decompressing it. The indoor throttling device 311 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 adjustment means such as a capillary tube, or the like. Among the indoor expansion devices 311, those mounted on the indoor unit 310 a are mounted on the indoor expansion device 311 a, and those mounted on the indoor unit 310 b are mounted on the indoor expansion device 311 b and the indoor unit 310 c. What is mounted on the indoor side expansion device 311c and the indoor unit 310d is illustrated as an indoor side expansion device 311d.

The indoor heat exchanger 312 functions as a radiator (condenser) during the heating cycle and as an evaporator during the cooling cycle, and performs heat exchange between air supplied from an indoor blower (not shown) and the refrigerant. Is condensed or liquefied or gasified.
In addition, although the air-type heat exchanger is demonstrated here as an example, it is not limited to this, The heat exchanger which cools and heats water like a chiller or a hot water supply, ie, a water heat exchanger, is not limited to this. It may be changed.
The indoor heat exchanger 312 corresponds to the “second heat exchanger” of the present invention.

The indoor unit 310 is provided with a temperature sensor (not shown). This temperature sensor detects the load at the installation location, and is composed of, for example, a thermistor. In addition, since the installation location and type of the temperature detection element are not particularly limited, the installation location and type may be selected according to the characteristics of the indoor unit 310 and the load to be detected. The temperature information detected by the temperature sensor is sent to the indoor unit control means 430 mounted on the indoor unit 310.

Of the indoor unit control means 430, those mounted on the indoor unit 310a are mounted on the indoor unit control means 430a, and those mounted on the indoor unit 310b are mounted on the indoor unit control means 430b and the indoor unit 310c. The thing mounted in the indoor unit 310d is illustrated as the indoor unit control means 430d.

Two refrigerant pipes connecting the parent branch unit 210 and the indoor unit 310a are illustrated as a liquid refrigerant pipe 010a and a gas refrigerant pipe 009a.
Two refrigerant pipes connecting the parent branch unit 210 and the indoor unit 310b are illustrated as a liquid refrigerant pipe 010b and a gas refrigerant pipe 009b.
Two refrigerant pipes connecting the child branch unit 220 and the indoor unit 310c are illustrated as a liquid refrigerant pipe 010c and a gas refrigerant pipe 009c.
Two refrigerant pipes connecting the child branch unit 220 and the indoor unit 310d are illustrated as a liquid refrigerant pipe 010d and a gas refrigerant pipe 009d.

As described above, the air conditioner 100 has a system configuration in which the heat source unit 110 is connected to the indoor unit 310 via the parent branch unit 210 and the child branch unit 220.

The air conditioner 100 is provided with a control means 400 that performs overall control of the entire system of the air conditioner 100. The control means 400 controls the drive frequency of the compressor 111, the rotation speed of the blower, the switching of the flow path switching device 112, the opening of each throttle means, the switching of the flow path switching device 214, the switching of the flow path switching device 224, and the like. Control. That is, the control means 400 controls each actuator (driving components such as the compressor 111, the flow path switching device 112, the blower, and the indoor-side throttle device 311) based on detection information from various sensors and instructions from the remote controller. It is like that. The various sensors include sensors not shown.

The control means 400 will be described in detail with reference to FIG. 2. The control means 400 includes a heat source unit control means 410, a parent branch unit control means 420a, a child branch unit control means 420b, and an indoor unit control means 430.

[Other target system configuration]
In FIG. 1, the case where the air conditioner 100 is a two-tube type cooling and heating simultaneous type in which the heat source unit 110 and the indoor unit 310 are connected by two refrigerant pipes via the parent branch unit 210 is taken as an example. However, the present invention is not limited to this, and the air-conditioning apparatus 100 may be configured by a three-tube type cooling / heating simultaneous type or a cooling / heating switching type connected by three refrigerant pipes.

FIG. 2 is a control block diagram showing an electrical configuration of the air conditioner 100. Based on FIG. 2, the control means 400 mounted in the air conditioning apparatus 100 will be described in detail.

As described above, the air conditioning apparatus 100 includes the control means 400. The control means 400 is composed of a microcomputer, a DSP, etc., and has a function of controlling the entire system of the air conditioning apparatus 100. The control means 400 can be configured by hardware such as a circuit device that realizes the function, or can be configured by an arithmetic device such as a microcomputer or a CPU and software executed thereon.

As described above, the control means 400 includes the heat source unit control means 410, the parent branch unit control means 420a, the child branch unit control means 420b, and the indoor unit control means 430. For the allocation of each control means, a control means corresponding to each unit may be provided, and each unit may perform independent distributed cooperative control in which control is independently performed, and any one unit has all control means. The unit having the control means may give a control command to another unit using communication or the like.

For example, as shown in FIG. 1, the heat source unit control means 410 for the heat source unit 110, the parent branch unit control means 420 a for the parent branch unit 210, the child branch unit control means 420 b for the child branch unit 220, and the indoor unit 310 If each of the indoor unit control means 430 is provided, each unit can perform control independently. Each control means can transmit information by wireless or wired communication means.

The heat source unit control means 410 has a function of controlling the refrigerant pressure state and the refrigerant temperature state in the heat source unit 110. The heat source unit control unit 410 includes a heat source unit control unit 411, a sensor information storage unit 412, an arithmetic processing circuit 413, an actuator control signal output unit 414, and the like.

Specifically, the heat source unit control unit 410 stores the information obtained by the heat source unit control unit 411 using the high pressure sensor 116, the low pressure sensor 117, etc. as data in the sensor information storage unit 412, and stores the stored information. After performing the arithmetic processing in the heat source unit 110 on the basis of the arithmetic processing circuit 413, the actuator control signal output means 414 outputs the operating frequency of the compressor 111, outputs the fan rotation speed of the blower, It has a function of outputting the switching of the path switching device 112.

Further, the heat source unit control means 410 defines the maximum number of indoor units 310 that can be connected to the parent branch unit 210 and the maximum value according to the capacity of the heat source unit 110, and transmits this information to the parent branch unit 210. It has a function.

The parent branch unit control unit 420a includes a branch unit control unit 421a, a sensor information storage unit 422a, an arithmetic processing circuit 423a, an actuator control signal output unit 424a, and the like.

Specifically, in the parent branch unit control means 420a, the branch unit controller 421a operates the flow path switching device 214 of the parent branch unit 210, the high pressure sensor 215 of the parent branch unit 210 itself, the intermediate pressure sensor. 216, the information obtained by the temperature sensor 217 and the like is stored as data in the sensor information storage means 422a, and the arithmetic processing circuit 423a performs arithmetic processing in the parent branch unit 210 based on the stored information, and then the actuator control The signal output means 424a has a function of controlling an electromagnetic valve output or an opening degree of an expansion valve (the expansion device 212, the expansion device 213).

The parent branch unit control means 420a also has a function of restricting the connection capacity and operation capacity of the indoor unit 310 based on the connection capacity and operation capacity information received from the heat source unit 110. It also has a function of transmitting restriction information on connection capacity and operation capacity to the branch unit control means 420b. Furthermore, if necessary, it also has means for transmitting the data stored in the sensor information storage means 422a.

The child branch unit control unit 420b includes a child branch unit control unit 421b, a sensor information storage unit 422b, an arithmetic processing circuit 423b, an actuator control signal output unit 424b, and the like.

Specifically, in the child branch unit control means 420b, the child branch unit controller 421b operates the flow path switching device 224 of the child branch unit 220, or the intermediate pressure / pressure sensor 226, temperature sensor of the child branch unit 220 itself. The information obtained by 227 or the like is stored as data in the sensor information storage means 422b, and the arithmetic processing circuit 423b performs arithmetic processing in the child branch unit 220 based on the stored information, and then the actuator control signal output means 424b. The function of controlling the solenoid valve output or the opening degree of the throttle device 223 is provided.

Furthermore, if necessary, it also has means for storing the pressure sensor information and temperature sensor information received from the parent branch unit control means 420a in the sensor information storage means 422b.
The child branch unit control means 420b also has a function of restricting the connection capacity and operating capacity of the indoor unit 310 based on the connection capacity and operating capacity restriction information received from the parent branch unit 210.

The indoor unit control means 430 has a function of controlling the degree of superheating during the cooling operation of the indoor unit 310 and the degree of supercooling during the heating operation of the indoor unit 310. Specifically, the indoor unit control means 430 changes the heat exchange area of the indoor heat exchanger 312, controls the fan rotation speed of the indoor blower, and controls the opening of the indoor expansion device 311. It has a function to do.

As described above, although not shown, if necessary, a temperature sensor for detecting the refrigerant discharge temperature, a sensor for detecting the refrigerant intake temperature, a temperature sensor for detecting the air-conditioning refrigerant suction temperature, heat exchange A temperature sensor for detecting the temperature of the refrigerant flowing into and out of the heat exchanger 113, a temperature sensor for detecting the outside air temperature taken into the heat source unit 110, and a temperature sensor for detecting the temperature of the refrigerant flowing into and out of the indoor heat exchanger 312. It is good to leave. Then, pressure information may be converted into saturation temperature information (in particular, a condensation temperature for a high pressure sensor, or an evaporation temperature for a low pressure sensor), or may be converted into specific enthalpy from pressure information and temperature information. . Information (measurement information such as temperature information and pressure information) detected by these various sensors is sent to the control means 400 and used for controlling each actuator.

<Operation of Air Conditioner 100>
Next, the operation of the air conditioning apparatus 100 will be described.
There are four operation modes in the operation mode executed by the air conditioner 100. One of the operation modes is a cooling operation mode in which all the indoor units 310 that are operating perform a cooling operation. One of the operation modes is a heating operation mode in which all of the indoor units 310 that are operating perform the heating operation. One of the operation modes is a cooling main operation mode in which the indoor unit 310 that is performing the heating operation and the indoor unit 310 that is performing the cooling operation are mixed, and the cooling load is larger. One of the operation modes is a heating main operation mode in which the indoor unit 310 that is performing the heating operation and the indoor unit 310 that is performing the cooling operation are mixed and the heating load is larger.

[Cooling operation mode]
First, the refrigerant circuit in the cooling operation mode when all the indoor units 310 in operation are in the cooling operation and the operation contents will be described with reference to FIG.

In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111, becomes a high-temperature / high-pressure gas refrigerant, and flows into the heat exchanger 113 through the flow path switching device 112. The high-pressure gas refrigerant that has flowed into the heat exchanger 113 is condensed by exchanging heat with air (or a heat medium such as water) supplied to the heat exchanger 113 to become a high-pressure liquid refrigerant. leak. The high-pressure liquid refrigerant flowing out from the heat exchanger 113 flows into the parent branch unit 210 through the check valve 114d and the high-pressure main pipe 001.

When the refrigerant flows out from the main branch unit 210 to the indoor unit 310a or the indoor unit 310b, the high-pressure liquid refrigerant that has flowed from the high-pressure main pipe 001 passes through the gas-liquid separator 211 and the expansion device 212, and the liquid refrigerant pipe 010a or liquid It flows to the refrigerant pipe 010b. The refrigerant flowing through the liquid refrigerant pipe 010a or the liquid refrigerant pipe 010b flows out from the parent branch unit 210 and then flows into the indoor unit 310a or the indoor unit 310b.

On the other hand, when the refrigerant flows out to the indoor unit 310c or the indoor unit 310d connected to the child branch unit 220, the high-pressure liquid refrigerant flowing from the high-pressure main pipe 001 is separated from the gas-liquid separator 211, the expansion device 212, and the liquid pipe. It flows out from the parent branch unit 210 via 003a. The refrigerant flowing through the liquid pipe 003a flows through the liquid distribution pipe 006, the liquid pipe 003c, and the internal liquid pipe of the child branch unit 220 to the liquid refrigerant pipe 010c or the liquid refrigerant pipe 010d. The refrigerant flowing through the liquid refrigerant pipe 010c or the liquid refrigerant pipe 010d flows out of the child branch unit 220 and then flows into the indoor unit 310c or the indoor unit 310d.

In the indoor unit 310, the low-pressure liquid and gas two-phase refrigerant or the low-pressure liquid refrigerant flows into the indoor heat exchanger 312 in the indoor expansion device 311. The low-pressure two-phase refrigerant or low-pressure liquid refrigerant that has flowed into the indoor heat exchanger 312 evaporates in the indoor heat exchanger 312, becomes a low-pressure gas refrigerant, and flows out of the indoor heat exchanger 312. Here, the air-conditioning target space is cooled. The low-pressure gas refrigerant flows out of the indoor unit 310 and then flows into the parent branch unit 210 or the child branch unit 220.

In the case of the parent branch unit 210, the low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 312 flows through the gas refrigerant pipe 009a or the gas refrigerant pipe 009b and out of the indoor unit 310a or the indoor unit 310b, and then enters the parent branch unit 210. Inflow. The low-pressure gas refrigerant that has flowed into the parent branch unit 210 is merged through the flow path switching device 214 (the flow path switching device 214a and the flow path switching device 214b) and flows to the low-pressure main pipe 002.

On the other hand, in the case of the child branch unit 220, the low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 312 flows through the gas refrigerant pipe 009c or the gas refrigerant pipe 009d and out of the indoor unit 310a or the indoor unit 310b, and then the child branch unit. 220 flows. The low-pressure gas refrigerant that has flowed into the child branch unit 220 passes through the flow path switching device 224 (the flow path switching device 224a and the flow path switching device 224b), passes through the low pressure pipe 005, and the low pressure merge pipe 008 to the parent branch unit 210. Inflow. The low-pressure refrigerant that has flowed to the parent branch unit 210 is merged in the low-pressure main pipe 002 and flows into the heat source unit 110.

The low-pressure gas refrigerant flowing into the heat source unit 110 is again sucked into the compressor 111 via the check valve 114a, the flow path switching device 112, and the accumulator 115. The circuit through which the refrigerant flows is used as the main circuit during the cooling operation.

[Heating operation mode]
Next, the refrigerant circuit in the heating operation mode when all the indoor units 310 being operated are in the heating operation, and the contents of the operation will be described with reference to FIG.

In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111 to become a high-temperature / high-pressure gas refrigerant, and flows into the parent branch unit 210 via the flow path switching device 112, the check valve 114c, and the high-pressure main pipe 001. .

When the refrigerant flows out from the parent branch unit 210 to the indoor unit 310a or the indoor unit 310b, the high-pressure gas refrigerant flowing from the high-pressure main pipe 001 is separated from the gas-liquid separator 211, the flow path switching device 214 (the flow path switching device 214a, It flows to the gas refrigerant pipe 009a or the gas refrigerant pipe 009b via the flow path switching device 214b). The refrigerant flowing through the gas refrigerant pipe 009a or the gas refrigerant pipe 009b flows out from the parent branch unit 210 and then flows into the indoor unit 310a or the indoor unit 310b.

On the other hand, when the refrigerant flows out to the indoor unit 310c or the indoor unit 310d connected to the child branch unit 220, the high-pressure gas refrigerant flowing from the high-pressure main pipe 001 passes through the gas-liquid separator 211 and the gas pipe 004a, Outflow from the parent branch unit 210. The refrigerant flowing through the gas pipe 004a flows to the gas refrigerant pipe 009c or the gas refrigerant pipe 009d via the gas distribution pipe 007, the gas pipe 004c, and the flow path switching device 224 (flow path switching device 224a, flow path switching device 224b). The refrigerant flowing through the gas refrigerant pipe 009c or the gas refrigerant pipe 009d flows out from the child branch unit 220 and then flows into the indoor unit 310c or the indoor unit 310d.

The high-pressure gas refrigerant that has flowed into the indoor unit 310 flows into the indoor heat exchanger 312, is condensed in the indoor heat exchanger 312, and flows out of the indoor heat exchanger 312 as a high-pressure liquid refrigerant. Here, the air-conditioning target space is heated. The high-pressure liquid refrigerant that has flowed out of the indoor heat exchanger 312 becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant in the indoor expansion device 311, and flows to the liquid refrigerant pipe 010. After flowing out from 310, it flows into the parent branch unit 210 or the child branch unit 220.

In the case of the parent branch unit 210, the low-pressure refrigerant flowing in the liquid refrigerant pipe 010a or the liquid refrigerant pipe 010b is merged in the parent branch unit 210 and then flows to the low-pressure main pipe 002 via the expansion device 213.

On the other hand, in the case of the child branch unit 220, there are two flow paths in the low-pressure refrigerant flowing through the liquid refrigerant pipe 010c or the liquid refrigerant pipe 010d. The first is that after the liquid pipe 003c, the liquid pipe 006, and the liquid pipe 003a are joined via the liquid pipe in the child branch unit 220, they are once merged in the parent branch unit 210, and then passed through the expansion device 213. , A flow path that flows to the low-pressure main pipe 002. The other is a flow path that flows into the main branch unit 210 via the throttle device 223 in the child branch unit 220, the low pressure pipe 005c, the low pressure merge pipe 008, and the low pressure pipe 005a, and flows to the low pressure main pipe 002. is there. The low-pressure two-phase refrigerant that has flowed into the low-pressure main pipe 002 flows out from the parent branch unit 210 and then flows into the heat source unit 110.

The low-pressure refrigerant flowing into the heat source unit 110 is again sucked into the compressor 111 via the check valve 114b, the heat exchanger 113, the flow path switching device 112, and the accumulator 115. The circuit through which the refrigerant flows is used as a main circuit during heating operation.

Next, an operation in which an evaporator (cooling operation indoor unit) and a condenser (heating operation indoor unit) are mixed in the load side unit will be described. As the mixed operation, there are two types of operation modes, a cooling main operation mode and a heating main operation mode. In the air conditioner 100, the operation mode is switched so that the capacity or efficiency is maximized by comparing the condensation temperature and the evaporation temperature of the refrigerant of the air conditioner 100 with the target values set in the heat source unit 110. It has become. Each operation mode will be described below.

[Cooling operation mode]
Next, the refrigerant circuit in the cooling main operation mode in which the indoor unit 310 is performing the cooling / heating mixed operation and the cooling load is larger than the heating load, and the operation contents thereof will be described with reference to FIG. Here, the cooling main operation mode will be described by taking as an example the case where the indoor unit 310c is in the cooling operation, the indoor unit 310b is in the heating operation, and the remaining indoor units are stopped.

In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111, becomes a high-temperature / high-pressure gas refrigerant, and flows into the heat exchanger 113 through the flow path switching device 112. The high-pressure gas refrigerant that has flowed into the heat exchanger 113 is condensed by exchanging heat with air (or a heat medium such as water) supplied to the heat exchanger 113 to become a high-pressure liquid and gas two-phase refrigerant, It flows out from the heat exchanger 113. The high-pressure two-phase refrigerant that has flowed out of the heat exchanger 113 flows into the parent branch unit 210 through the check valve 114d and the high-pressure main pipe 001.

In the main branching unit 210, the high-pressure two-phase refrigerant flowing from the high-pressure main pipe 001 is separated into a high-pressure saturated gas refrigerant and a high-pressure saturated liquid refrigerant by the gas-liquid separator 211. The high-pressure saturated gas refrigerant separated by the gas-liquid separator 211 flows to the gas refrigerant pipe 009b via the flow path switching device 214b. The high-pressure gas refrigerant flowing through the gas refrigerant pipe 009b flows out from the parent branch unit 210 and then flows into the indoor unit 310b.

The refrigerant flowing into the indoor unit 310b is condensed in the indoor heat exchanger 312b, becomes a high-pressure liquid refrigerant, and flows out of the indoor heat exchanger 312b. At this time, the air-conditioning target space is heated. The high-pressure liquid refrigerant that has flowed out of the indoor heat exchanger 312b becomes an intermediate-pressure liquid and gas two-phase refrigerant or an intermediate-pressure liquid refrigerant in the indoor expansion device 311b, and flows to the liquid refrigerant pipe 010b. After flowing out of the indoor unit 310b, it is reused as a refrigerant used during cooling.

On the other hand, the high-pressure saturated liquid refrigerant separated by the gas-liquid separator 211 merges with the refrigerant flowing from the indoor unit 310b via the expansion device 212, and the liquid pipe 003a, the liquid distribution pipe 006, the liquid pipe 003c, The liquid flows through the internal liquid pipe of the branch unit 229 to the liquid refrigerant pipe 010 c and flows out of the child branch unit 220. The refrigerant flowing out from the child branch unit 220 flows into the indoor unit 310c.

In the indoor unit 310c, in the indoor expansion device 311c, a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant flows into the indoor heat exchanger 312c. The low-pressure two-phase refrigerant or low-pressure liquid refrigerant that has flowed into the indoor heat exchanger 312c evaporates in the indoor heat exchanger 312c, becomes a low-pressure gas refrigerant, and flows out of the indoor heat exchanger 312c. At this time, the air-conditioning target space is cooled. The low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 312c flows through the gas refrigerant pipe 009c, flows out of the indoor unit 310c, and then flows into the child branch unit 220.

If the amount of liquid refrigerant that accumulates in the section of the liquid pipe increases, the pressure in the liquid pipe rises and the differential pressure with the heating indoor unit decreases, so the amount of refrigerant circulating through the heating indoor unit decreases, and the heating capacity Decrease. Therefore, in order to release the liquid accumulated in the liquid line, the liquid line pressure is adjusted by allowing the liquid accumulated in the liquid line to flow into the low-pressure main pipe 002 or the low-pressure pipe 005 by appropriately opening the expansion device 213 or the expansion device 223. . Therefore, the refrigerant flowing out from the expansion device 213 or the expansion device 223 becomes a low-pressure two-phase refrigerant by mixing with the low-pressure gas refrigerant flowing in from the indoor unit 310c and the flow path switching device 224c during the cooling operation.

The low-pressure two-phase refrigerant is joined and flows to the low-pressure main pipe 002. The low-pressure two-phase refrigerant that has flowed into the low-pressure main pipe 002 flows out from the parent branch unit 210 and then flows into the heat source unit 110. The low-pressure two-phase refrigerant that has flowed into the low-pressure main pipe 002 flows into the heat source unit 110. The low-pressure two-phase refrigerant that has flowed into the heat source unit 110 is sucked into the compressor 111 again via the check valve 114a, the flow path switching device 112, and the accumulator 115. The circuit through which the refrigerant flows is used as the main circuit during the cooling main operation.

[Heating main operation mode]
Next, the refrigerant circuit in the heating main operation mode in which the indoor unit 310 performs the cooling and heating mixed operation, the indoor unit 310c performs the heating operation, and the heating load is larger than the cooling load, and the operation The contents will be described with reference to FIG. Here, the heating main operation mode will be described by taking as an example the case where the indoor unit 310a is in the cooling operation and the indoor unit 310c is in the heating operation.

In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111 to become a high-temperature / high-pressure gas refrigerant, and flows into the parent branch unit 210 via the flow path switching device 112, the check valve 114c, and the high-pressure main pipe 001. .

In the parent branch unit 210, the high-pressure gas refrigerant flowing from the high-pressure main pipe 001 flows out of the parent branch unit 210 via the gas-liquid separator 211 and the gas pipe 004a. The refrigerant flowing through the gas pipe 004a flows to the gas refrigerant pipe 009c via the gas distribution pipe 007, the gas pipe 004c, and the flow path switching device 224a. The refrigerant flowing through the gas refrigerant pipe 009c flows out from the child branch unit 220 and then flows into the indoor unit 310c.

The high-pressure gas refrigerant that has flowed into the indoor unit 310c flows into the indoor heat exchanger 312c, is condensed in the indoor heat exchanger 312c, and flows out of the indoor heat exchanger 312c as high-pressure liquid refrigerant. Here, the air-conditioning target space is heated. The high-pressure liquid refrigerant that has flowed out of the indoor heat exchanger 312c becomes an intermediate-pressure liquid and gas two-phase refrigerant or an intermediate-pressure liquid refrigerant in the indoor expansion device 311c, and flows to the liquid refrigerant pipe 010c. After flowing out of the indoor unit 310c, it flows into the parent branch unit 210 through the child branch unit 220, the internal liquid pipe of the child branch unit 220, the liquid pipe 003c, the liquid distribution pipe 006, and the liquid pipe 003a.

The intermediate-pressure refrigerant that has flowed into the main branch unit 210 flows to the liquid refrigerant pipe 010a. The refrigerant flows out from the parent branch unit 210 and then flows into the indoor unit 310a. The refrigerant flowing into the indoor unit 310a becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant in the indoor expansion device 311a and flows into the indoor heat exchanger 312a. The low-pressure liquid refrigerant that has flowed into the indoor heat exchanger 312a evaporates in the indoor heat exchanger 312a, becomes a low-pressure gas refrigerant, and flows out of the indoor heat exchanger 312a. At this time, the air-conditioning target space is cooled.

If the amount of liquid refrigerant that accumulates in the section of the liquid pipe increases, the pressure in the liquid pipe rises and the differential pressure with the heating indoor unit decreases, so the amount of refrigerant circulating through the heating indoor unit decreases, and the heating capacity Decrease. Therefore, in order to release the liquid accumulated in the liquid line, the pressure of the liquid line is adjusted by allowing the liquid accumulated in the liquid line to flow into the low-pressure main pipe 002 by opening the expansion device 213 appropriately. Therefore, the refrigerant flowing out from the main branch unit 210 becomes a low-pressure two-phase refrigerant by mixing the low-pressure gas refrigerant flowing in from the indoor unit 310a and the liquid refrigerant flowing in from the expansion device 213.

The refrigerant that has flowed out of the indoor heat exchanger 312a flows into the gas refrigerant pipe 009a. The low-pressure two-phase refrigerant flowing from the gas refrigerant pipe 009a flows out from the indoor unit 310a and then flows into the parent branch unit 210. The low-pressure two-phase refrigerant that has flowed into the parent branch unit 210 flows to the low-pressure main pipe 002 via the flow path switching device 214 (flow path switching device 214a). The low-pressure two-phase refrigerant that has flowed into the low-pressure main pipe 002 flows out from the parent branch unit 210 and then flows into the heat source unit 110 through the low-pressure main pipe 002.

The low-pressure gas refrigerant flowing into the heat source unit 110 is again sucked into the compressor 111 via the check valve 114b, the heat exchanger 113, the flow path switching device 112, and the accumulator 115. The circuit through which the refrigerant flows is used as the main circuit during the driving operation.

[Target of refrigerant control]
FIG. 3 is a schematic diagram showing a trend of refrigerant pressure in the air conditioner 100. Based on FIG. 3, the refrigerant | coolant pressure in the air conditioning apparatus 100 is demonstrated. In FIG. 3, five indoor units 310 are connected to each of the parent branch unit 210 and the child branch unit 220.

When the refrigerant pressure flowing out from the heat source unit 110 is the highest and flows into the parent branch unit 210, the pressure becomes PH1. Here, when the high-pressure gas refrigerant moves from the parent branch unit 210 to the child branch unit 220, the pressure becomes PH2 after receiving the pipe pressure loss of the gas pipe 004. Here, when it returns to the child branch unit 220 via the indoor unit 310 that is connected to the child branch unit 220 for heating operation, it becomes PM2 that is an intermediate pressure. Then, it flows into the liquid pipe line of the parent branch unit 210 via the liquid pipe 003 and becomes PM1. The flow of the refrigerant described above describes the flow path when not passing through the expansion device 223 of the child branch unit 220.

Here, if the differential pressure between the high pressure PH1 and the intermediate pressure PM1 of the parent branch unit 210 is the first intermediate differential pressure dPHM1, and the differential pressure between the high pressure PH2 and the intermediate pressure PM2 of the child branch unit 220 is the second intermediate differential pressure dPHM2. As a pressure trend, as shown in FIG. 3, dPHM1 ≧ dPHM2. This means that it is difficult for the refrigerant to flow into the indoor unit 310 for heating operation connected to the child branch unit 220 side. That is, as the child branch unit 220 moves away from the parent branch unit 210, the intermediate differential pressure decreases due to pipe pressure loss, and the heating capacity of the indoor unit 310 for heating operation connected to the child branch unit 220 side is reduced.

As a factor satisfying dPHM1 ≧ dPHM2, pressure loss due to the liquid pipe 003 and the gas pipe 004 between the parent branch unit 210 and the child branch unit 220 can be considered. The multi-air conditioner for buildings is designed where the size of the pipe diameter of the liquid pipe 003 with respect to the liquid refrigerant flow rate is smaller than the conventional one because the size of the liquid pipe diameter is related to the amount of additional charging refrigerant. Therefore, as shown in FIG. 3, the differential pressure between the intermediate pressures PM2 and PM1 becomes dominant due to the liquid pipe pressure loss. As a simple method for alleviating this phenomenon, it is conceivable to increase the diameter of the liquid pipe 003, but there is a risk that the additional refrigerant charging amount will increase as described above.

In order to avoid the above state, in the air conditioner 100, the refrigerant staying in the child branch unit 220 is released downstream from the expansion device 223 of the child branch unit 220. By doing so, according to the air conditioning apparatus 100, it is possible to make dPHM1 and dPHM2 close without increasing the size of the liquid pipe 003. That is, the air conditioning apparatus 100 approximates the second intermediate differential pressure dPHM2 to the first intermediate differential pressure dPHM1 by adjusting the opening degree of the expansion device 212, the expansion device 213, and the expansion device 223.

Also, a method of setting dPHM1≈dPHM2 by reducing the intermediate pressure PM1 and the intermediate pressure PM2 to the low pressure line with the opening of the expansion device 213 and the expansion device 223 being the maximum opening is also conceivable. However, conversely, when the refrigerant bypasses to the expansion device side, the refrigerant does not flow to the indoor unit 310 that performs the heating operation. Therefore, it is necessary to set the intermediate pressure PM1 and the intermediate pressure PM2 as appropriate pressure values when the cooling / heating mixed operation is performed.

As described above, the expansion device 213 and the expansion device 223 are adjusted by the air conditioner 100 so that the intermediate differential pressure dPHM1 of the parent branch unit 210 and the intermediate differential pressure dPHM2 of the sub-branch unit 220 are arbitrarily set to the target intermediate differential pressure dPHMm. Control is sufficient. The target intermediate differential pressure dPHMm is set to the same value here in the parent branch unit 210 and the child branch unit 220, but may be set separately if necessary.

That is, the flow of the control process will be described in detail later, but the air conditioner 100 determines the expansion device 213 and the expansion device based on the differential pressure information between the pressure information of the intermediate pressure sensor 226 and the pressure information of the intermediate pressure sensor 216. Intermediate pressure control is performed by adjusting the opening degree of H.223 so that the intermediate differential pressure dPHM2 is maintained high.

[Control processing in parent branch unit control means 420a of parent branch unit 210]
The processing contents in the above-described refrigerant control parent branch unit control means 420a will be described in detail. FIG. 4 is a flowchart showing the flow of control processing in the parent branch unit control means 420a of the parent branch unit 210 of the air conditioner 100.

After starting the control process (step S101), the parent branch unit control means 420a acquires information on the high pressure sensor 215 and information on the intermediate pressure sensor 216 in the parent branch unit 210 (step S102). The acquired information is stored in the sensor information storage means 422a as the value of the high pressure sensor 215 as PH1 and the value of the intermediate pressure sensor 216 as PM1. Thereafter, the parent branch unit control means 420a transmits the PH1 information to the child branch unit control means 420b of the child branch unit 220 (step S103).

The information on the high pressure and the intermediate pressure acquired in step S102 is converted into information on the intermediate differential pressure dPHM1 (step S104). Specifically, the parent branch unit control means 420a calculates the intermediate differential pressure dPHM1 by the arithmetic processing circuit 423a using the formula “dPHM1 = PH1−PM1”.

The parent branch unit control means 420a determines what processing should be performed using the intermediate differential pressure dPHM1 calculated in step S104. First, in step S105, the master branching unit control means 420a compares the intermediate differential pressure dPHM1 with a value obtained by subtracting the set value α from the target intermediate differential pressure dPHMm based on a mathematical formula (dPHM1> dPHMm−α).

When the determination result in step S105 is No, the parent branch unit control unit 420a performs a control operation for decreasing the opening degree of the expansion device 212 and a control operation for increasing the opening amount of the expansion device 213 (step S107). In addition, about the control amount of the opening degree of the diaphragm | throttle device 212 and the diaphragm | throttle device 213 here, you may set arbitrarily and should just set suitably according to an operating condition.

When the determination result in step S105 is Yes, the parent branch unit control means 420a compares the intermediate differential pressure dPHM1 and the target intermediate differential pressure dPHMm plus the set value α based on the formula (dPHM1 ≦ dPHMm + α) ( Step S106).

When the determination result in step S106 is No, the parent branch unit control unit 420a performs a control operation for increasing the opening degree of the expansion device 212 and a control operation for decreasing the opening amount of the expansion device 213 (step S108). In addition, about the control amount of the opening degree of the diaphragm | throttle device 212 and the diaphragm | throttle device 213 here, you may set arbitrarily and should just set suitably according to an operating condition.

When the determination result in step S106 is Yes, the parent branch unit control means 420a maintains the opening degrees of the expansion device 212 and the expansion device 213 (step S109). The parent branch unit control means 420a determines whether the parent branch unit 210 is thermo-off or stopped after step S107, step S108, and step S109 are finished (step S110). If the determination result in step S110 is No, the parent branch unit control unit 420a sequentially re-executes the processing from step S102 at regular intervals, for example. If the determination result in step S110 is Yes, the control is terminated (step S111).

Here, the set value α used in the mathematical formula is a value determined by a dead zone in the automatic control of the air conditioner 100. Inserting a dead zone improves control robustness. Therefore, the set value α may be selected as necessary. Using such a flowchart, the master branch unit 210 can perform refrigerant control of the intermediate differential pressure dPHM1.

“Thermo-OFF” is to stop driving the compressor 111 when the temperature of the air-conditioning target space reaches the set temperature. Further, the improvement in robustness means that the control of the air conditioner 100 is less likely to be influenced by disturbance. Furthermore, the dead zone is a range of setting values set so that no control is performed. These meanings are the same in the following description.

[Control Processing in Child Branch Unit Control Unit 420b of Child Branch Unit 220]
The processing contents in the above-described refrigerant control child branching unit control means 420b will be specifically described. FIG. 5 is a flowchart showing a flow of control processing in the child branch unit control means 420b of the child branch unit 220 of the air conditioner 100.

The child branch unit control means 420b starts the control process (step S201), and acquires information on the intermediate pressure sensor 226 in the child branch unit 220 (step S202). Thereafter, the child branch unit control means 420b receives the PH1 information from the parent branch unit control means 420a of the parent branch unit 210 (step S203). The acquired information is stored in the sensor information storage unit 422b as PH1 as PH2 and intermediate pressure sensor 226 as PM2.

The information on the high pressure and the intermediate pressure acquired in steps S202 and S203 is converted into information on the intermediate differential pressure dPHM2 (step S204). Specifically, the child branch unit control means 420b calculates the intermediate differential pressure dPHM2 by the arithmetic processing circuit 423b using the equation “dPHM2 = PH2−PM2”.

The child branch unit control means 420b determines what processing should be performed using the intermediate differential pressure dPHM2 calculated in step S204. First, in step S205, the sub-branch unit control means 420b compares the intermediate differential pressure dPHM2 and the value obtained by subtracting the set value α from the target intermediate differential pressure dPHMm based on the mathematical formula (dPHM2> dPHMm−α).

When the determination result in step S205 is No, the child branch unit control unit 420b performs a control operation for increasing the opening degree of the expansion device 223 (step S207). In addition, about the control amount of the opening degree of the expansion device 223 here, you may set arbitrarily and should just set suitably according to a driving | running condition.

If the determination result in step S205 is Yes, the child branch unit control unit 420b
The intermediate differential pressure dPHM2 is compared with a value obtained by adding the set value α from the target intermediate differential pressure dPHMm (dPHM2 ≦ dPHMm + α) (step S206).

When the determination result in step S206 is No, the child branch unit control unit 420b performs a control operation for reducing the opening degree of the expansion device 223 (step S208). In addition, about the control amount of the opening degree of the expansion device 223 here, you may set arbitrarily and should just set suitably according to a driving | running condition.

If the determination result in step S206 is Yes, the child branch unit control means 420b maintains the opening degree of the expansion device 223 (step S209). The child branch unit control means 420b determines whether or not the child branch unit 220 is thermo-off or stopped after step S207, step S208, and step S209 are completed (step S210). If the determination result in step S210 is No, the child branch unit control unit 420b sequentially re-executes the processing from step S202 at regular intervals, for example. If the determination result in step S210 is Yes, the control is terminated (step S211).

Here, the set value α used in the mathematical formula is a value determined by a dead zone in the automatic control of the air conditioner 100. Inserting a dead zone improves control robustness. Therefore, the set value α may be selected as necessary. Here, the pressure value PH1 of the parent branch unit 210 is used as the pressure value PH2. If necessary, a high pressure sensor may be provided in the gas pipe in the child branch unit 220, and this sensor information may be set as PH2. If such a flowchart is used, refrigerant control of the intermediate differential pressure dPHM2 can be performed in the sub branch unit 220.

If the control processing of the parent branch unit control means 420a and the child branch unit control means 420b as described above is used, the refrigerant pressure can be appropriately controlled. Therefore, the pipe length from the parent branch unit 210 to the indoor unit 310 is increased. It becomes possible. As a result, a plurality of child branch units 220 can be connected, and the piping length between the child branch unit 220 and the indoor unit 310 can be shortened. Further, the pipe diameter between the parent branch unit 210 and the child branch unit 220 can be reduced.

Here, the refrigerant that can be used for the air conditioner 100 will be described. Examples of the refrigerant that can be used in the refrigeration cycle of the air conditioner 100 include a non-azeotropic refrigerant mixture, a pseudo-azeotropic refrigerant mixture, and a single refrigerant. Non-azeotropic refrigerant mixture includes R407C (R32 / R125 / R134a) which is an HFC (hydrofluorocarbon) refrigerant. Since this non-azeotropic refrigerant mixture is a mixture of refrigerants having different boiling points, it has a characteristic that the composition ratio of the liquid-phase refrigerant and the gas-phase refrigerant is different. The pseudo azeotropic refrigerant mixture includes R410A (R32 / R125) and R404A (R125 / R143a / R134a) which are HFC refrigerants. This pseudo azeotrope refrigerant has the same characteristic as that of the non-azeotrope refrigerant and has an operating pressure of about 1.6 times that of R22.

Also, the single refrigerant includes R22 which is an HCFC (hydrochlorofluorocarbon) refrigerant, R134a which is an HFC refrigerant, and the like. Since this single refrigerant is not a mixture, it has the property of being easy to handle. In addition, natural refrigerants such as carbon dioxide, propane, isobutane, and ammonia can be used. R22 represents chlorodifluoromethane, R32 represents difluoromethane, R125 represents pentafluoromethane, R134a represents 1,1,1,2-tetrafluoromethane, and R143a represents 1,1,1-trifluoroethane. Yes. Therefore, it is good to use the refrigerant | coolant according to the use and the objective of the air conditioning apparatus 100. FIG.

[Effects of the air conditioner 100]
FIG. 6 is a schematic construction diagram schematically showing an example of a construction diagram of the air conditioner 100 in which a plurality of child branch units 220 are connected. The effect which the air conditioning apparatus 100 show | plays is demonstrated based on FIG. In addition, in FIG. 6, an example of the construction drawing of the conventional air conditioning apparatus (henceforth the air conditioning apparatus 100X) is also shown in figure as a comparative example. Moreover, in any air conditioner, a state in which ten indoor units 310 are connected is shown as an example. Further, the configuration of the air conditioner 100X is indicated by adding “X” at the end.

Since the air conditioner 100X shown in FIG. 6 does not perform the intermediate pressure control as described in FIG. 3, the heating capacity of the indoor unit 310X for heating operation connected to the child branch unit 220X side is reduced. End up. This is because the intermediate differential pressure decreases due to pipe pressure loss as the child branch unit 220X moves away from the parent branch unit 210X.

On the other hand, in the air conditioner 100, by adopting the control processing shown in FIGS. 4 and 5, intermediate pressure control is executed, and a plurality of child branch units 220 can be connected. That is, the child branch unit 220 can be connected to a position away from the heat source unit 110. Therefore, it becomes possible to install so that the piping length between the child branch unit 220 and the indoor unit 310 becomes short. Further, the pipe diameter between the parent branch unit 210 and the child branch unit 220 can be reduced.

As described above, according to the air conditioner 100, it is possible to design a pipe that can reduce the piping construction cost and the refrigerant additional charging amount. Specifically, as shown in FIG. 6, the line arrangement of the child branch units 220 allows the pipe diameter to be smaller for the child branch unit 220 connected away from the parent branch unit 210 on the paper surface. Can be reduced. Moreover, since the handling of the refrigerant piping connecting the parent branch unit 210, the child branch unit 220, and the indoor unit 310 can be simplified, a reduction in the amount of additional charge refrigerant can be expected, and the cost required for piping construction can be suppressed. Is possible.

001 High pressure main pipe, 002 Low pressure main pipe, 003 liquid pipe, 003a liquid pipe, 003b liquid pipe, 003c liquid pipe, 004 gas pipe, 004a gas pipe, 004b gas pipe, 004c gas pipe, 005 low pressure pipe, 005a low pressure pipe, 005b low pressure Pipe, 005c low pressure pipe, 006 liquid distribution pipe, 007 gas distribution pipe, 008 low pressure merge pipe, 009 gas refrigerant pipe, 009a gas refrigerant pipe, 009b gas refrigerant pipe, 009c gas refrigerant pipe, 009d gas refrigerant pipe, 010 liquid refrigerant pipe 010a liquid refrigerant pipe, 010b liquid refrigerant pipe, 010c liquid refrigerant pipe, 010d liquid refrigerant pipe, 011 refrigerant pipe, 012 refrigerant pipe, 100 air conditioner, 100X air conditioner, 110 heat source unit, 111 compressor, 112 flow path Switching device, 13 heat exchanger, 114 check valve, 114a check valve, 114b check valve, 114c check valve, 114d check valve, 115 accumulator, 116 high pressure sensor, 117 low pressure sensor, 210 parent branch unit, 210X parent Branch unit, 211 gas-liquid separator, 212 throttle device, 213 throttle device, 214 channel switching device, 214a channel switching device, 214b channel switching device, 215 high pressure sensor, 216 intermediate pressure sensor, 217 temperature sensor, 220 child branch unit, 220X child branch unit, 223 throttling device, 224 flow path switching device, 224a flow path switching device, 224b flow path switching device, 224c flow path switching device, 226 intermediate pressure sensor, 227 temperature sensor, 229 child Branch unit, 310 rooms Unit, 310X indoor unit, 310a indoor unit, 310b indoor unit, 310c indoor unit, 310d indoor unit, 311 indoor side throttle device, 311a indoor side throttle device, 311b indoor side throttle device, 311c indoor side throttle device, 311d indoor side throttle Equipment, 312 indoor heat exchanger, 312a indoor heat exchanger, 312b indoor heat exchanger, 312c indoor heat exchanger, 400 control means, 410 heat source unit control means, 411 heat source unit control unit, 412 sensor information storage Means 413 arithmetic processing circuit 414 actuator control signal output means 420a parent branch unit control means 420b child branch unit control means 421a branch unit controller 421b child branch unit controller 422a Sensor information storage means, 422b Sensor information storage means, 423a arithmetic processing circuit, 423b arithmetic processing circuit, 424a actuator control signal output means, 424b actuator control signal output means, 430 indoor unit control means, 430a indoor unit control means, 430b indoor unit Control means, 430c indoor unit control means, 430d indoor unit control means.

Claims (6)

1. At least one heat source unit equipped with a compressor and a first heat exchanger;
   At least one indoor unit on which the second heat exchanger and the indoor expansion device are mounted;
   A first branch unit connected between the heat source unit and the indoor unit, and having at least two first expansion devices mounted thereon;
   A second branch unit connected between the first branch unit and the indoor unit and having at least one second throttle device mounted thereon,
   A refrigeration cycle is formed by connecting the compressor, the first heat exchanger, the indoor expansion device, and the second heat exchanger,
   The first throttling device and the second throttling device are provided downstream of the indoor throttling device in the flow of refrigerant during operation of supplying the refrigerant discharged from the compressor to the second heat exchanger. And
   An air conditioner that controls the intermediate pressure of the refrigeration cycle by adjusting the opening of the first throttle device and the second throttle device.
2. By adjusting the opening degree of the first throttle device and the second throttle device, a second intermediate differential pressure, which is a differential pressure between the high pressure and the intermediate pressure in the second branch unit, is increased in the first branch unit. The air conditioning apparatus according to claim 1, wherein the air conditioner is approximated to a first intermediate differential pressure that is a differential pressure between the first pressure and the intermediate pressure.
3. In the one equipped with the two first diaphragm devices,
   When the first intermediate differential pressure is equal to or less than a value obtained by subtracting a set value from the first target intermediate differential pressure, the opening of one of the first expansion devices is decreased and the opening of the other expansion device To increase the first intermediate differential pressure closer to the first target intermediate differential pressure,
   When the first intermediate differential pressure is greater than a value obtained by subtracting a set value from the first target intermediate differential pressure and greater than a value obtained by adding the set value to the first target intermediate differential pressure, Increasing the opening and decreasing the opening of the other throttle device brings the first intermediate differential pressure closer to the first target intermediate differential pressure,
   When the first intermediate differential pressure is greater than a value obtained by subtracting a set value from the first target intermediate differential pressure and is equal to or less than a value obtained by adding the set value to the first target intermediate differential pressure, The air conditioning apparatus according to claim 2, wherein the opening degree is maintained.
4. When the second intermediate differential pressure is equal to or less than a value obtained by subtracting a set value from the second target intermediate differential pressure, the second intermediate differential pressure is increased by increasing the opening of the second expansion device. Close to the differential pressure,
   When the second intermediate differential pressure is greater than a value obtained by subtracting a set value from the second target intermediate differential pressure, and greater than a value obtained by adding the set value to the second target intermediate differential pressure, the second throttle device By reducing the opening, the second intermediate differential pressure approaches the second target intermediate differential pressure,
   When the second intermediate differential pressure is greater than a value obtained by subtracting a set value from the second target intermediate differential pressure, and is equal to or less than a value obtained by adding the set value to the second target intermediate differential pressure, The air conditioning apparatus according to claim 2 or 3, wherein the opening degree is maintained.
5. The air conditioner according to claim 4, wherein the first target intermediate differential pressure and the second target intermediate differential pressure have the same value.
6. The air conditioner according to claim 3 or 4, wherein the set value is determined by a dead zone in automatic control.

Images