The present invention relates to an air-conditioning system.
Hitherto, an air-conditioning system including an outdoor unit and a plurality of indoor units is known. For example, PTL 1 (International Publication No. 2015/029160) describes an air-conditioning system in which a single outdoor unit and a plurality of indoor units are connected via a connection pipe. In PTL 1, the connection pipe is branched into some numbers of connection pipes according to the number of the indoor units.
As for refrigerant that is transferred through a liquid-side refrigerant passage running between an outdoor unit and indoor units, it is possible to perform operation with a smaller amount of refrigerant filled (the amount of refrigerant filled in a refrigerant circuit) in the case of gas-liquid two-phase transfer to transfer refrigerant in a gas-liquid two-phase state as compared to the case of liquid transfer to transfer refrigerant in a liquid state, so employing the gas-liquid two-phase transfer can be regarded as a method of achieving refrigerant saving. In PTL 1, gas-liquid two-phase transfer is performed by disposing a pressure reducing valve in the outdoor unit.
Here, in the case where the amount of refrigerant filled is reduced by performing gas-liquid two-phase transfer, when some of the indoor units are in an operating state and the other indoor units are in an operation stop state (a state where an operation start command is not input or an operation suspension state, such as thermo-off), it is presumable that the amount of circulating refrigerant is not normally ensured in the indoor units in an operating state (operating indoor units) and, as a result, reliability decreases. In other words, since the amount of refrigerant filled when gas-liquid two-phase transfer is performed is less than the amount of refrigerant filled when liquid transfer is performed, when refrigerant to be fed to the operating indoor units flows from a branch part into indoor-side pipes that communicate with the non-operating indoor units, it is presumable that the amount of circulating refrigerant is not normally ensured in the operating indoor units and, as a result, reliability decreases. An air-conditioning system that minimizes a decrease in reliability is provided.
An air-conditioning system according to one or more embodiments of the present invention is an air-conditioning system configured to perform a refrigeration cycle in a refrigerant circuit, and includes an outdoor unit, a plurality of indoor units, and a connection pipe. The connection pipe is disposed between the outdoor unit and the indoor units. The connection pipe at least forms a refrigerant passage through which gas-liquid two-phase refrigerant flows. The connection pipe includes a branch portion and a trap portion. The branch portion includes an indoor-side pipe group. The indoor-side pipe group is a plurality of indoor-side pipes each communicating with any one of the indoor units. The branch portion is configured to diverge refrigerant flowing from the outdoor unit side. The trap portion is provided in at least any one of the indoor-side pipes. The trap portion is configured to be filled with refrigerant in a gas state.
With the air-conditioning system according to one or more embodiments, in the air-conditioning system in which refrigerant in a gas-liquid two-phase state passes through the connection pipe connecting the outdoor unit and the indoor units, the trap portion is provided in the indoor-side pipe(s) included in the connection pipe (branch portion). Thus, in the case where the amount of refrigerant filled is reduced as compared to the existing one by performing gas-liquid two-phase transfer, when part of the indoor units (operating indoor unit(s)) is/are in an operating state and the other indoor unit(s) (stopped indoor unit(s)) is/are in an operation stop state, gas refrigerant can be filled in the trap portion(s) (of the indoor-side pipe(s) communicating with the stopped indoor unit(s)). As a result, flow of refrigerant to the stopped indoor unit(s) can be suppressed. Thus, a shortage of the amount of circulating refrigerant in the operating indoor unit(s) can be suppressed. Therefore, a decrease in reliability is minimized.
The “operation stop state” here contains not only a state where an operation stop command is input and the operation is stopped, a state where the operation is stopped as a result of cutting off the power, and a state where an operation start command is not input and the operation is not performed but also a state where the operation is temporarily stopped by thermo-off, or the like.
An air-conditioning system according to one or more embodiments further includes a pressure reducing valve. The pressure reducing valve is configured to decompress refrigerant such that refrigerant flowing from the outdoor unit to the indoor units passes through the connection pipe in a gas-liquid two-phase state.
In an air-conditioning system according to one or more embodiments, the trap portion is provided in one of the indoor-side pipes, including a portion of which an installation level is lower than an other one of the indoor-side pipes of the indoor-side pipe group.
In an air-conditioning system according to one or more embodiments, the indoor units include a first indoor unit and a second indoor unit. An installation level of the second indoor unit is lower than an installation level of the first indoor unit. The indoor-side pipe group includes a first indoor-side pipe and a second indoor-side pipe. The first indoor-side pipe communicates with the first indoor unit. The second indoor-side pipe communicates with the second indoor unit. The trap portion is provided in the second indoor-side pipe.
In an air-conditioning system according to one or more embodiments, the connection pipe includes a plurality of the branch portions. The trap portion is provided in the indoor-side pipe included in the branch portion closest to the outdoor unit.
In an air-conditioning system according to one or more embodiments, the trap portion has an upward extended portion. The upward extended portion extends upward. The upward extended portion is disposed in the associated indoor-side pipes.
An air-conditioning system according to one or more embodiments further includes a branch pipe unit. The branch pipe unit is preassembled and connected to another pipe on an installation site. The branch pipe unit is part or all of the branch portion. The branch pipe unit includes a main pipe and a connection pipe. The main pipe communicates with the indoor-side pipe group. The main pipe is located on the outdoor unit side with respect to the indoor-side pipe group in the refrigerant circuit. The connection pipe connects the main pipe and the indoor-side pipe group. The connection pipe is configured to diverge refrigerant flowing from the main pipe to the indoor-side pipe group. An extending direction of each of the main pipe and the connection pipe is a horizontal direction.
An air-conditioning system according to one or more embodiments further includes a branch pipe unit. The branch pipe unit is preassembled and connected to another pipe on an installation site. The branch pipe unit is part or all of the branch portion. The branch pipe unit includes a main pipe and a connection pipe. The main pipe communicates with the indoor-side pipe group. The main pipe is located on the outdoor unit side with respect to the indoor-side pipe group in the refrigerant circuit. The connection pipe connects the main pipe and the indoor-side pipe group. The connection pipe is configured to diverge refrigerant flowing from the main pipe to the indoor-side pipe group. An extending direction of each of the main pipe and the connection pipe is a vertical direction. The upward extended portion is disposed over the main pipe, the connection pipe, and the associated indoor-side pipes.
An air-conditioning system according to one or more embodiments further includes a branch pipe unit. The branch pipe unit is preassembled and connected to another pipe on an installation site. The branch pipe unit is part or all of the branch portion. The branch pipe unit includes a main pipe and a connection pipe. The main pipe communicates with the indoor-side pipe group. The main pipe is located on the outdoor unit side with respect to the indoor-side pipe group in the refrigerant circuit. The connection pipe connects the main pipe and the indoor-side pipe group. The connection pipe is configured to diverge refrigerant flowing from the main pipe to the indoor-side pipe group. An extending direction of the main pipe is a horizontal direction. An extending direction of the connection pipe is a vertical direction. The upward extended portion is disposed over the connection pipe and the associated indoor-side pipes.
An air-conditioning system according to one or more embodiments further includes a branch pipe unit. The branch pipe unit is preassembled and connected to another pipe on an installation site. The branch pipe unit is part or all of the branch portion. The branch pipe unit includes a main pipe and a connection pipe. The main pipe communicates with the indoor-side pipe group. The main pipe is located on the outdoor unit side with respect to the indoor-side pipe group in the refrigerant circuit. The connection pipe connects the main pipe and the indoor-side pipe group. The connection pipe is configured to diverge refrigerant flowing from the main pipe to the indoor-side pipe group. The main pipe extends along a downward direction. The connection pipe includes a turnaround portion. The turnaround portion turns refrigerant, flowing from the main pipe, around to an upward direction. The upward extended portion is disposed over the connection pipe and the associated indoor-side pipes.
Hereinafter, an air-conditioning system 100 according to one or more embodiments of the present invention will be described. The following embodiments are specific examples and do not limit the technical scope. The following embodiments may be modified as needed without departing from the purport. In the following description, upper, lower, right, left, front, and rear directions are directions indicated in
In the present invention, a “horizontal direction” includes a right-left direction and a front-rear direction. The “horizontal direction” includes not only a complete horizontal direction but also a direction that inclines within the range of a predetermined angle (for example, 30 degrees) with respect to a horizontal line.
In the present invention, a “vertical direction” includes an up-down direction. The “vertical direction” includes not only a complete vertical direction but also a direction that inclines within the range of a predetermined angle (for example, 45 degrees) with respect to a vertical line.
In the present invention, a “right angle” includes not only a completely right angle (90 degrees) but also “substantially a right angle” (an angle that varies within the range of a predetermined angle (30 degrees) with respect to 90 degrees.
In the present invention, an “operation stop state” includes not only a state where an operation stop command is input and the operation is stopped, a state where the operation is stopped as a result of cutting off the power, and a state where an operation start command is not input and the operation is not performed but also a state where the operation is temporarily stopped by thermo-off, or the like.
In the present invention, it is assumed that a “method” appropriate for an installation environment and design specifications is selected as needed for “joining” and “connection” of portions. The “method” is not limited, and, for example, brazing connection, flaring connection, flange connection, or the like, is assumed.
The air-conditioning system 100 mainly includes an outdoor unit 10, a plurality of (here, four or more) indoor units 40 (40a, 40b, 40c, 40d, . . . ), and a liquid-side connection pipe La and a gas-side connection pipe Ga that connect the outdoor unit 10 and the indoor units 40.
In the air-conditioning system 100, the refrigerant circuit RC is formed by connecting the outdoor unit 10 and the indoor units 40 with the liquid-side connection pipe La and the gas-side connection pipe Ga. In the air-conditioning system 100, a vapor compression refrigeration cycle in which refrigerant enclosed in the refrigerant circuit RC is compressed, cooled or condensed, decompressed, heated or evaporated, and then compressed again takes place. Refrigerant filled in the refrigerant circuit RC is not limited, and, for example, R32 is employed.
The refrigerant circuit RC mainly includes an outdoor-side circuit RC1 formed in the outdoor unit 10, an indoor-side circuit RC2 formed in each of the indoor units 40, and a connection circuit RC3 connecting the outdoor-side circuit RC1 and the indoor-side circuits RC2. The connection circuit RC3 includes a liquid-side connection circuit RC3a that functions as a liquid-side refrigerant passage between the outdoor unit 10 and the indoor units 40 and a gas-side connection circuit RC3b that functions as a gas-side refrigerant passage, between the outdoor unit 10 and the indoor units 40.
In the air-conditioning system 100, gas-liquid two-phase transfer that refrigerant is transferred in a gas-liquid two-phase state is performed in the liquid-side connection pipe La extending between the outdoor unit 10 and the indoor units 40. More specifically, as for refrigerant that is transferred through the liquid-side connection pipe La extending between the outdoor unit 10 and the indoor units 40, in light of the fact that an operation can be performed with a smaller amount of refrigerant filled while a decrease in capacity is minimized when the refrigerant is transferred in a gas-liquid two-phase state as compared to when the refrigerant is transferred in a liquid state, the air-conditioning system 100 is configured such that gas-liquid two-phase transfer is performed in the liquid-side connection circuit RC3a to achieve refrigerant saving. The air-conditioning system 100 includes a “pressure reducing valve” (an outdoor second control valve 17 (described later)) for decompressing refrigerant in the outdoor unit 10 in order to realize gas-liquid two-phase transfer.
A thermal load here is a thermal load at which a process is required in the indoor unit(s) 40 in operation (operating indoor unit(s)), and is calculated based on, for example, any one or some or all of a set temperature that is set in the operating indoor unit(s), a temperature in an object space(s) SP in which the operating indoor unit(s) is/are installed, the amount of circulating refrigerant, the number(s) of rotations of an indoor fan(s) 45, the number of rotations of a compressor 11, the capacity of an outdoor heat exchanger 14, the capacity of each indoor heat exchanger 42, and the like.
The outdoor unit 10 is, for example, installed outdoors, for example, a roof floor or veranda of the building B1, or installed outside the rooms, such as a basement (other than the object spaces SP). The outdoor unit 10 is connected to the plurality of indoor units 40 via the liquid-side connection pipe La and the gas-side connection pipe Ga, and makes up part of the refrigerant circuit RC (outdoor-side circuit RC1).
The outdoor unit 10 mainly includes a plurality of refrigerant pipes (a first pipe P1 to a twelfth pipe P12), the compressor 11, an accumulator 12, a four-way valve 13, the outdoor heat exchanger 14, a subcooler 15, an outdoor first control valve 16, the outdoor second control valve 17, an outdoor third control valve 18, a liquid-side stop valve 19, and a gas-side stop valve 20 as devices that make up the outdoor-side circuit RC1.
The first pipe P1 connects the gas-side stop valve 20 and a first port of the four-way valve 13. The second pipe P2 connects an inlet port of the accumulator 12 and a second port of the four-way valve 13. The third pipe P3 connects an outlet port of the accumulator 12 and a suction port of the compressor 11. The fourth pipe P4 connects a discharge port of the compressor 11 and a third port of the four-way valve 13. The fifth pipe P5 connects a fourth port of the four-way valve 13 and a gas-side outlet/inlet port of the outdoor heat exchanger 14. The sixth pipe P6 connects a liquid-side outlet/inlet port of the outdoor heat exchanger 14 and one end of the outdoor first control valve 16. The seventh pipe P7 connects the other end of the outdoor first control valve 16 and one end of a main passage 151 of the subcooler 15. The eighth pipe P8 connects the other end of the main passage 151 of the subcooler 15 and one end of the outdoor second control valve 17. The ninth pipe P9 connects the other end of the outdoor second control valve 17 and one end of the liquid-side stop valve 19. The tenth pipe P10 connects a portion between both ends of the sixth pipe P6 and one end of the outdoor third control valve 18. The eleventh pipe P11 connects the other end of the outdoor third control valve 18 and one end of a sub-passage 152 of the subcooler 15. The twelfth pipe P12 connects the other end of the sub-passage 152 of the subcooler 15 and a portion between both ends of the first pipe P1. These refrigerant pipes (P1 to P12) each may be actually made up of a single pipe or may be made up of a plurality of pipes connected via a joint, or the like.
The compressor 11 is a device that compresses low-pressure refrigerant into high pressure in the refrigeration cycle. In one or more embodiments, the compressor 11 has a hermetically sealed structure in which a positive-displacement, such as a rotary type and a scroll type, compression element is driven for rotation by a compressor motor (not shown). Here, the compressor motor is able to control operation frequency with an inverter. With this configuration, displacement control over the compressor 11 is enabled.
The accumulator 12 is a tank for restricting excessive suction of liquid refrigerant into the compressor 11. The accumulator 12 has a predetermined volume according to the amount of refrigerant filled in the refrigerant circuit RC.
The four-way valve 13 is a flow switch valve for switching the flow of refrigerant in the refrigerant circuit RC. The four-way valve 13 can be switched between a normal cycle mode and a reverse cycle mode. The four-way valve 13, when in the normal cycle mode, communicates the first port (first pipe P1) with the second port (second pipe P2) and communicates the third port (fourth pipe P4) with the fourth port (fifth pipe P5) (see the solid lines in the four-way valve 13 in
The outdoor heat exchanger 14 is a heat exchanger that functions as a condenser (or radiator) or an evaporator (or heater) for refrigerant. The outdoor heat exchanger 14 functions as the condenser for refrigerant during normal cycle operation (operation when the four-way valve 13 is in the normal cycle mode). The outdoor heat exchanger 14 functions as the evaporator for refrigerant during reverse cycle operation (operation when the four-way valve 13 is in the reverse cycle mode). The outdoor heat exchanger 14 includes a plurality of heat transfer tubes and heat transfer fins (not shown). The outdoor heat exchanger 14 is configured such that heat is exchanged between refrigerant in the heat transfer tubes and air (outdoor air flow (described later)) passing around the heat transfer tubes or the heat transfer fins.
The subcooler 15 is a heat exchanger that converts inflow refrigerant into liquid refrigerant in a subcooled state. The subcooler 15 is, for example, a double-tube heat exchanger. The main passage 151 and the sub-passage 152 are formed in the subcooler 15. The subcooler 15 is configured such that refrigerant flowing through the main passage 151 and refrigerant flowing through the sub-passage 152 exchange heat with each other.
The outdoor first control valve 16 is an electronic expansion valve of which the opening degree is controllable. The outdoor first control valve 16 decompresses inflow refrigerant or adjusts the flow rate according to the opening degree. The outdoor first control valve 16 is disposed between the outdoor heat exchanger 14 and the subcooler 15 (main passage 151). In other words, the outdoor first control valve 16 may also be regarded as being disposed between the outdoor heat exchanger 14 and the liquid-side connection pipe La.
The outdoor second control valve 17 (which corresponds to the “pressure reducing valve” in the claims) is an electronic expansion valve of which the opening degree is controllable. The outdoor second control valve 17 decompresses inflow refrigerant or adjusts the flow rate according to the opening degree. The outdoor second control valve 17 is disposed between the subcooler 15 (main passage 151) and the liquid-side stop valve 19. When the opening degree of the outdoor second control valve 17 is controlled, refrigerant flowing from the outdoor unit 10 to the indoor units 40 can be placed in a gas-liquid two-phase state.
The outdoor third control valve 18 is an electronic expansion valve of which the opening degree is controllable. The outdoor third control valve 18 decompresses inflow refrigerant or adjusts the flow rate according to the opening degree. The outdoor third control valve 18 is disposed between the outdoor heat exchanger 14 and the subcooler 15 (sub-passage 152).
The liquid-side stop valve 19 is a manual valve disposed at a connection point between the ninth pipe P9 and the liquid-side connection pipe La. One end of the liquid-side stop valve 19 is connected to the ninth pipe P9, and the other end of the liquid-side stop valve 19 is connected to the liquid-side connection pipe La.
The gas-side stop valve 20 is a manual valve disposed at a connection point between the first pipe P1 and the gas-side connection pipe Ga. One end of the gas-side stop valve 20 is connected to the first pipe P1, and the other end of the gas-side stop valve 20 is connected to the gas-side connection pipe Ga.
The outdoor unit 10 includes an outdoor fan 25 that generates outdoor air flow that passes through the outdoor heat exchanger 14. The outdoor fan 25 is a fan that supplies the outdoor heat exchanger 14 with outdoor air flow as a cooling source or heating source for refrigerant flowing through the outdoor heat exchanger 14. The outdoor fan 25 includes an outdoor fan motor (not shown) that is a drive source, and the start, stop, and number of rotations of the outdoor fan 25 are controlled as needed.
A plurality of outdoor-side sensors (not shown) for detecting the status (mainly, pressure or temperature) of refrigerant in the refrigerant circuit RC is disposed in the outdoor unit 10. The outdoor-side sensors are a pressure sensor and a temperature sensor, such as a thermistor and a thermocouple. Examples of the outdoor-side sensors include a suction pressure sensor that detects the pressure of refrigerant at a suction side of the compressor 11 (suction pressure), a discharge pressure sensor that detects the pressure of refrigerant at a discharge side of the compressor 11 (discharge pressure), a refrigerant temperature sensor that detects the temperature of refrigerant in the outdoor heat exchanger 14 (for example, the degree of subcooling SC), and an outside air temperature sensor that detects the temperature of outside air.
The outdoor unit 10 includes an outdoor unit control unit that controls the operations and statuses of the devices included in the outdoor unit 10. The outdoor unit control unit includes a microcomputer including a CPU, a memory, and the like. The outdoor unit control unit is electrically connected to the devices (11, 13, 16, 17, 18, 25, and the like), included in the outdoor unit 10, and the outdoor-side sensors 26, and inputs or outputs signals to or from each other. The outdoor unit control unit individually sends or receives control signals, or the like, to or from an indoor unit control unit (described later) or remote control unit (not shown) of each indoor unit 40 via a communication line.
The indoor units 40 are connected to the outdoor unit 10 via the liquid-side connection pipe La and the gas-side connection pipe Ga. Each indoor unit 40 is disposed in parallel or series with the other indoor units 40 with respect to the outdoor unit 10. In
Each indoor unit 40 makes up part of the refrigerant circuit RC (indoor-side circuit RC2). Each indoor unit 40 mainly includes a plurality of refrigerant pipes (a thirteenth pipe P13, a fourteenth pipe P14), an indoor expansion valve 41, and the indoor heat exchanger 42, as devices that make up the indoor-side circuit RC2.
The thirteenth pipe P13 connects the liquid-side connection pipe La and a liquid-side refrigerant inlet/outlet port of the indoor heat exchanger 42. The fourteenth pipe P14 connects a gas-side refrigerant inlet/outlet port of the indoor heat exchanger 42 and the gas-side connection pipe Ga. These refrigerant pipes (P13, P14) each may be actually made up of a single pipe or may be made up of a plurality of pipes connected via a joint, or the like.
The indoor expansion valve 41 is an electronic expansion valve of which the opening degree is controllable. The indoor expansion valve 41 decompresses inflow refrigerant or adjusts the flow rate according to the opening degree. The indoor expansion valve 41 is disposed in the thirteenth pipe P13 and is located between the liquid-side connection pipe La and the indoor heat exchanger 42. The indoor expansion valve 41, during normal cycle operation, decompresses refrigerant flowing from the liquid-side connection pipe La into the indoor unit 40.
The indoor heat exchanger 42 is a heat exchanger that functions as an evaporator (or heater) or condenser (or radiator) for refrigerant. The indoor heat exchanger 42, during normal cycle operation, functions as the evaporator for refrigerant. The indoor heat exchanger 42, during reverse cycle operation, functions as the condenser for refrigerant. The indoor heat exchanger 42 includes a plurality of heat transfer tubes and heat transfer fins (not shown). The indoor heat exchanger 42 is configured such that heat is exchanged between refrigerant in the heat transfer tubes and air (indoor-side air flow (described later)) passing around the heat transfer tubes or the heat transfer fins.
The indoor unit 40 includes an indoor fan 45 for taking in air in the object space SP, allowing the air to pass through the indoor heat exchanger 42 to exchange heat with refrigerant, and then sending the air to the object space SP again. The indoor fan 45 includes an indoor fan motor (not shown) that is a drive source. The indoor fan 45, while being driven, generates indoor air flow as a heating source or cooling source for refrigerant flowing through the indoor heat exchanger 42.
Indoor-side sensors (not shown) for detecting the status (mainly, pressure or temperature) of refrigerant in the refrigerant circuit RC are disposed in the indoor unit 40. The indoor-side sensors are a pressure sensor and a temperature sensor, such as a thermistor and a thermocouple. Examples of the indoor-side sensors include a temperature sensor that detects the temperature of refrigerant in the indoor heat exchanger 42 (for example, the degree of superheating) and a pressure sensor that detects the pressure of refrigerant.
The indoor unit 40 includes an indoor unit control unit that controls the operations and statuses of the devices included in the indoor unit 40. The indoor unit control unit includes a microcomputer including a CPU, a memory, and the like. The indoor unit control unit is electrically connected to the devices (41, 45) included in the indoor unit 40 and the indoor-side sensors, and inputs or outputs signals to or from each other. The indoor unit control unit is connected to the outdoor unit control unit and the remote control unit (not shown) via the communication line. The indoor unit control unit sends or receives control signals, or the like, to or from the outdoor unit control unit or the remote control unit.
The liquid-side connection pipe La and the gas-side connection pipe Ga are connection pipes that connect the outdoor unit 10 and the indoor units 40, and are installed on site. The pipe length and pipe diameter of each of the liquid-side connection pipe La and the gas-side connection pipe Ga are selected as needed according to design specifications and an installation environment.
The liquid-side connection pipe La is a pipe that makes up the liquid-side connection circuit RC3 (liquid-side connection circuit RC3a) between the outdoor unit 10 and the indoor units 40. The liquid-side connection pipe La is made up of a plurality of pipes, joints, and the like, connected. Specifically, the liquid-side connection pipe La includes a plurality of connection pipes (a first liquid-side connection pipe L1, a second liquid-side connection pipe L2, a third liquid-side connection pipe L3, a fourth liquid-side connection pipe L4, a fifth liquid-side connection pipe L5, . . . ), a plurality of branch parts BP (hereinafter, referred to as “liquid-side branch parts BPa”), and the like. The connection pipes (L1, L2, L3, L4, L5, . . . ) included in the liquid-side connection pipe La each may be actually made up of a single pipe or may be made up of a plurality of pipes connected via a joint, or the like.
One end of the first liquid-side connection pipe L1 is connected to the liquid-side stop valve 19 of the outdoor unit 10. The first liquid-side connection pipe L1 is disposed on the outdoor unit 10 side with respect to the other connection pipes (L2, L3, L4, L5, . . . ) in the liquid-side connection circuit RC3a. The first liquid-side connection pipe L1, the second liquid-side connection pipe L2, and the third liquid-side connection pipe L3 are connected at the liquid-side branch part BPa located on the most outdoor unit 10 side in the liquid-side connection circuit RC3a, and communicate with one another.
The other connection pipes (L2, L3, L4, L5, . . . ) included in the liquid-side connection pipe La form refrigerant passages between the first liquid-side connection pipe L1 and the associated indoor units 40. In one or more embodiments, the second liquid-side connection pipe L2 is associated with the indoor units 40a, 40b, or the like, and the third liquid-side connection pipe L3 and the fourth liquid-side connection pipe L4 are associated with the indoor units 40c, 40d, or the like. The fifth liquid-side connection pipe L5 is associated with the other indoor units 40, or the like.
One end side of each of the second liquid-side connection pipe L2 and the third liquid-side connection pipe L3 communicates with the other end side of the first liquid-side connection pipe L1 via the branch part BP. The second liquid-side connection pipe L2 and the third liquid-side connection pipe L3 are disposed in parallel with each other with respect to the first liquid-side connection pipe L1.
One end side of each of the fourth liquid-side connection pipe L4 and the fifth liquid-side connection pipe L5 communicates with the other end side of the third liquid-side connection pipe L3 via the branch part BP. The fourth liquid-side connection pipe L4 and the fifth liquid-side connection pipe L5 are disposed in parallel with each other with respect to the third liquid-side connection pipe L3.
The gas-side connection pipe Ga is a pipe that makes up a gas-side connection circuit RC3 (gas-side connection circuit RC3b) between the outdoor unit 10 and the indoor units 40 and through which, during operation, low-pressure refrigerant flows. The gas-side connection pipe Ga is made up of a plurality of pipes, joints, and the like, connected. The gas-side connection pipe Ga includes a plurality of connection pipes (a first gas-side connection pipe G1, a second gas-side connection pipe G2, a third gas-side connection pipe G3, a fourth gas-side connection pipe G4, and a fifth gas-side connection pipe G5), a plurality of branch parts BP (hereinafter, referred to as “gas-side branch parts BPb”), and the like. The connection pipes (G1, G2, G3, G4, G5, . . . ) included in the gas-side connection pipe Ga each may be actually made up of a single pipe or may be made up of a plurality of pipes connected via a joint, or the like.
One end of the first gas-side connection pipe G1 is connected to the gas-side stop valve 20 of the outdoor unit 10. The first gas-side connection pipe G1 is disposed on the outdoor unit 10 side with respect to the other connection pipes (G2, G3, G4, G5, . . . ) in the gas-side connection circuit RC3b. The first gas-side connection pipe G1, the second gas-side connection pipe G2, and the third gas-side connection pipe G3 are connected at the gas-side branch part BPb located on the most outdoor unit 10 side in the gas-side connection circuit RC3b, and communicate with one another.
The other connection pipes (G2, G3, G4, G5, . . . ) included in the gas-side connection pipe Ga form refrigerant passages between the first gas-side connection pipe G1 and the associated indoor units 40. In one or more embodiments, the second gas-side connection pipe G2 is associated with the indoor units 40a, 40b, or the like, and the third gas-side connection pipe G3 and the fourth gas-side connection pipe G4 are associated with the indoor units 40c, 40d, or the like. The fifth gas-side connection pipe G5 is associated with the other indoor units 40, or the like.
One end side of each of the second gas-side connection pipe G2 and the third gas-side connection pipe G3 communicates with the other end side of the first gas-side connection pipe G1 via the branch part BP. The second gas-side connection pipe G2 and the third gas-side connection pipe G3 are disposed in parallel with each other with respect to the first gas-side connection pipe G1.
One end side of each of the fourth gas-side connection pipe G4 and the fifth gas-side connection pipe G5 communicates with the other end side of the third gas-side connection pipe G3 via the branch part BP. The fourth gas-side connection pipe G4 and the fifth gas-side connection pipe G5 are disposed in parallel with each other with respect to the third gas-side connection pipe G3.
In one or more embodiments, as shown in
In the following description, one or both of the liquid-side connection pipe La and the gas-side connection pipe Ga are referred to as “connection pipe”. In the connection circuit RC3, of the connection pipes connected at the branch parts BP, the connection pipes located on the outdoor unit 10 side (for example, L1 for L2 and L3 or L3 for L4 and L5) are referred to as “outdoor unit-side connection pipes CP1”, and any one or some or all of the connection pipes communicating with the outdoor unit-side connection pipe CP1 (for example, L2 and L3 for L1 or L4 and L5 for L3) are referred to as “indoor unit-side connection pipes CP2”.
The branch parts BP (the liquid-side branch part BPa and the gas-side branch part BPb) included in the connection pipe each are a part that diverges refrigerant flowing from the outdoor unit 10 side (that is, the outdoor unit-side connection pipe CP1 side) to the indoor unit-side connection pipes CP2 and a part that merges refrigerant flowing from the indoor unit-side connection pipes CP2 side.
In the air-conditioning system 100, each branch part BP is made up of a branch pipe unit 50 (a first branch pipe unit 51 or a second branch pipe unit 60). The details of each branch pipe unit 50 will be described later.
Hereinafter, the flow of refrigerant in the refrigerant circuit RC will be described. In the air-conditioning system 100, mainly, the normal cycle operation, such as cooling operation, and the reverse cycle operation, such as heating operation, take place. Here, a low pressure in the refrigeration cycle is the pressure of refrigerant that is taken into the compressor 11, and a high pressure in the refrigeration cycle is the pressure of refrigerant that is discharged from the compressor 11.
During normal cycle operation, part of refrigerant flowing through the sixth pipe P6 branches into the ninth pipe P9, passes through the outdoor third control valve 18 and the subcooler 15 (sub-passage 152), and is then returned to the outdoor-side circuit RC1 (compressor 11) via the gas-side connection circuit RC3b.
Specifically, as the normal cycle operation is started, refrigerant is taken into the compressor 11, compressed to a high pressure of the refrigeration cycle, and then discharged (see a to b in
Gas refrigerant flowing into the outdoor heat exchanger 14 exchanges heat with outdoor air flow that is sent by the outdoor fan 25, radiates heat, and condenses in the outdoor heat exchanger 14 (see b to d in
One part of refrigerant having branched in process of flowing through the sixth pipe P6 passes through the outdoor first control valve 16 and flows into the main passage 151 of the subcooler 15. Refrigerant flowing into the main passage 151 of the subcooler 15 exchanges heat with refrigerant flowing through the sub-passage 152 to be cooled and further enters a state with a degree of subcooling (see d to e in
Liquid refrigerant flowing out from the main passage 151 of the subcooler 15 undergoes decompression or adjustment of the flow rate according to the opening degree of the outdoor second control valve 17, enters a gas-liquid two-phase state, and becomes intermediate-pressure refrigerant lower in pressure than high-pressure refrigerant and higher in pressure than low-pressure refrigerant (see e to f in
Gas-liquid two-phase refrigerant flowing out from the outdoor unit 10 passes through the liquid-side connection circuit RC3a and flows into the indoor-side circuit RC2 of each operating indoor unit. Refrigerant flowing through the liquid-side connection circuit RC3a decreases in pressure because of a pressure loss (see f to g in
The other part of refrigerant having branched in process of flowing through the sixth pipe P6 in the outdoor-side circuit RC1 flows into the outdoor third control valve 18, undergoes decompression or adjustment of the flow rate according to the opening degree of the outdoor third control valve 18, and then flows into the sub-passage 152 of the subcooler 15. Refrigerant flowing into the sub-passage 152 of the subcooler 15 exchanges heat with refrigerant flowing through the main passage 151, passes through the twelfth pipe P12, and merges into refrigerant flowing through the first pipe P1.
Refrigerant flowing into the indoor-side circuit RC2 flows into the indoor expansion valve 41, undergoes decompression to a low pressure in the refrigeration cycle according to the opening degree of the indoor expansion valve 41 (see g to h in
Refrigerant flowing into the indoor heat exchanger 42 exchanges heat with indoor air flow that is sent by the indoor fan 45 to evaporate into gas refrigerant (see h to a in
Refrigerant flowing out from the indoor-side circuit RC2 flows through the gas-side connection circuit RC3b and flows into the outdoor-side circuit RC1. Refrigerant flowing into the outdoor-side circuit RC1 flows through the first pipe P1, passes through the four-way valve 13 and the second pipe P2, and flows into the accumulator 12. Refrigerant flowing into the accumulator 12 is temporarily accumulated and then taken into the compressor 11 again.
During reverse cycle operation, the four-way valve 13 is controlled to a reverse cycle mode, and refrigerant filled in the refrigerant circuit RC mainly circulates in order of the outdoor-side circuit RC1 (compressor 11), the gas-side connection circuit RC3b, the indoor-side circuit RC2 (the indoor heat exchanger 42 and the indoor expansion valve 41) of each operating indoor unit, the liquid-side connection circuit RC3a, and the outdoor-side circuit RC1 (the outdoor second control valve 17, the subcooler 15, the outdoor first control valve 16, the outdoor heat exchanger 14, and the compressor 11).
Specifically, as the reverse cycle operation is started, refrigerant is taken into the compressor 11, compressed to a high pressure, and then discharged in the outdoor-side circuit RC1. In the compressor 11, displacement control commensurate with a thermal load that is required from the operating indoor unit(s) is performed. Gas refrigerant discharged from the compressor 11 flows out from the outdoor unit 10 through the fourth pipe P4 and the first pipe P1, and flows into the indoor-side circuit RC2 of each operating indoor unit 40 through the gas-side connection circuit RC3b.
Refrigerant flowing into the indoor-side circuit RC2 flows into the indoor heat exchanger 42, and exchanges heat with indoor air flow that is sent by the indoor fan 45 to condense. Refrigerant flowing out from the indoor heat exchanger 42 flows into the indoor expansion valve 41, and undergoes decompression to a low pressure in the refrigeration cycle according to the opening degree of the indoor expansion valve 41. Then, refrigerant flows out from the indoor-side circuit RC2.
Refrigerant flowing out from the indoor-side circuit RC2 flows into the outdoor-side circuit RC1 through the liquid-side connection circuit RC3a. Refrigerant flowing into the outdoor-side circuit RC1 passes through the ninth pipe P9, the outdoor second control valve 17, the eighth pipe P8, the subcooler 15 (main passage 151), the seventh pipe P7, the outdoor first control valve 16, and the sixth pipe P6 and flows into the liquid-side outlet/inlet port of the outdoor heat exchanger 14.
Refrigerant flowing into the outdoor heat exchanger 14 exchanges heat with outdoor air flow that is sent by the outdoor fan 25 to evaporate in the outdoor heat exchanger 14. After that, refrigerant flows out from the gas-side outlet/inlet port of the outdoor heat exchanger 14, passes through the fifth pipe P5, the four-way valve 13, and the second pipe P2, and flows into the accumulator 12. Refrigerant flowing into the accumulator 12 is temporarily accumulated and then taken into the compressor 11 again.
Each branch pipe unit 50 is a unit for making up the branch part BP in the connection circuit RC3. Each branch pipe unit 50 is preassembled at a factory before installation on site, or the like, and connected to other pipes (here, the outdoor unit-side connection pipe CP1 and the indoor unit-side connection pipes CP2) on installation site.
Each branch pipe unit 50 disposed in the refrigerant circuit RC is any one of the first branch pipe unit 51 and the second branch pipe unit 60 having a function of providing a trap in the connection circuit RC3. In each branch part BP, an optimal one of the first branch pipe unit 51 and the second branch pipe unit 60 is selected.
The main pipe 52 mainly extends along the x direction (see
Each branch pipe 54 mainly extends along the x direction (see
The connection pipe portion 58 connects the main pipe 52 and the branch pipe group 55 (branch pipes 54) in the first branch pipe unit 51. In one or more embodiments, as shown in
Each second branch pipe unit 60 includes a main pipe 70, a branch pipe group 88 made up of a plurality of (here, two) branch pipes 80, and a connection pipe portion 90. In the second branch pipe unit 60, the main pipe 70 and each branch pipe 80 are connected via the connection pipe portion 90 and communicate with each other.
The main pipe 70 (which corresponds to the “outdoor-side pipe” in the claims) is a pipe that sends refrigerant flowing from the outdoor unit-side connection pipe CP1 to the connection pipe portion 90 or a pipe that sends refrigerant flowing from the connection pipe portion 90 to the outdoor unit-side connection pipe CP1. The main pipe 70 is located on the outdoor unit 10 side with respect to the connection pipe portion 90 in an installation state. The main pipe 70 is associated in a one-to-one correspondence with any one of the outdoor unit-side connection pipes CP1. The main pipe 70 has a first main pipe portion 71 that mainly extends along the x direction (see
In one or more embodiments, the branch pipe group 88 includes two branch pipes 80 (80a, 80b). Each branch pipe 80 (which corresponds to the “indoor-side pipe” in the claims) is located on the associated indoor unit 40 side with respect to the connection pipe portion 90 in an installation state. One ends 801 of the branch pipes 80 are individually connected to the second connection portions 902 of the connection pipe portion 90 in an installation state. Each branch pipe 80 is associated in a one-to-one correspondence with any one of the indoor unit-side connection pipes CP2, and the other end 802 is connected to the associated indoor unit-side connection pipe CP2.
The size of each branch pipe 80 is selected as needed according to an installation environment and design specifications. In one or more embodiments, the size of each branch pipe 80 is a size suitable in providing the liquid-side connection circuit RC3a (specifically, the size is set to greater than or equal to two eighths to less than or equal to six eighths). Here, “two eighths” and “six eighths” are conventionally used names of pipe size. Specifically, “two eighths” here is ¼ inches, the outside diameter is 6.35 mm (or a value approximate to this), and the inside diameter is 4.75 mm (or a value approximate to this). “Six eighths” here is ¾ inches, the outside diameter is 19.05 mm (or a value approximate to this), and the inside diameter is 16.95 mm (or a value approximate to this).
Each branch pipe 80 includes a portion extending along the x direction and a portion extending along the y direction that intersects with the x direction. Specifically, the branch pipe 80 includes a first extended portion 81, a second extended portion 82, a turnaround portion 83, a third extended portion 84, and a fourth extended portion 85. In one or more embodiments, the portions (81 to 85) of the branch pipe 80 continuously extend in order of the first extended portion 81, the second extended portion 82, the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85, and are integrated.
The first extended portion 81 is a portion that mainly extends along the x direction (that is, the extending direction of the main pipe 70). The first extended portion 81 is located on the main pipe 70 side with respect to the other portions (the second extended portion 82 to the fourth extended portion 85) in the branch pipe 80. In other words, the first extended portion 81 is located on the outdoor unit 10 side with respect to the other portions (the second extended portion 82, the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85) of the branch pipe 80 in the connection circuit RC3 in an installation state. In one or more embodiments, one end of the first extended portion 81 corresponds to one end 801 of the branch pipe 80, and is connected to the second connection portion 902 of the connection pipe portion 90 in an installation state. The other end of the first extended portion 81 is connected to the second extended portion 82. The first extended portion 81 sends inflow refrigerant from one of the connection pipe portion 90 and the second extended portion 82 to the other in an installation state.
The second extended portion 82 mainly extends along the y direction (that is, the direction that intersects with the extending direction of the main pipe 70). In one or more embodiments, the second extended portion 82 extends at right angles with respect to the extending direction of each of the first extended portion 81 and the main pipe 70. The second extended portion 82 extends between the first extended portion 81 and the turnaround portion 83. The second extended portion 82 is located on the main pipe 70 side with respect to the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85. In other words, the second extended portion 82 is located on the indoor unit 40 side with respect to the first extended portion 81 in the connection circuit RC3 in an installation state and is located on the outdoor unit 10 side with respect to the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85. One end of the second extended portion 82 is connected to the first extended portion 81. The other end of the second extended portion 82 is connected to the turnaround portion 83. The second extended portion 82 sends inflow refrigerant from one of the first extended portion 81 and the turnaround portion 83 to the other in an installation state.
The turnaround portion 83 is a portion that mainly extends along the y direction (a direction in which the second extended portion 82 extends), bends, extends along the x direction, further bends, and extends along the y direction (a direction in which the third extended portion 84 extends). The turnaround portion 83 is a portion that extends between the second extended portion 82 and the turnaround portion 83 to connect both. The turnaround portion 83 is located on the main pipe 70 side with respect to the third extended portion 84 and the fourth extended portion 85. In other words, the turnaround portion 83 is located between the second extended portion 82 and the third extended portion 84, located on the indoor unit 40 side with respect to the first extended portion 81 and the second extended portion 82, and located on the outdoor unit 10 side with respect to the third extended portion 84 and the fourth extended portion 85 in the connection circuit RC3 in an installation state. One end of the turnaround portion 83 is connected to the other end of the second extended portion 82. The other end of the turnaround portion 83 is connected to the third extended portion 84. The turnaround portion 83 provides a refrigerant passage that turns inflow refrigerant around from one of the second extended portion 82 and the third extended portion 84 to the other in an installation state. The turnaround portion 83 is shown in the drawing so as to have a portion extending linearly in the x direction; however, the turnaround portion 83 may be made from a pipe bent into a U-shape. The configuration of such a U-shaped pipe can reduce the influence of pressure loss of refrigerant.
The third extended portion 84 is a portion that mainly extends along the y direction (that is, the direction that intersects with the extending direction of the main pipe 70). The extending direction of the third extended portion 84 is a direction opposite from the extending direction of the second extended portion 82. The third extended portion 84 is a portion that extends between the turnaround portion 83 and the fourth extended portion 85 to connect both. The third extended portion 84 is located on the main pipe 70 side with respect to the fourth extended portion 85. In other words, the third extended portion 84 is located on the indoor unit 40 side with respect to the first extended portion 81, the second extended portion 82, and the turnaround portion 83 and located on the outdoor unit 10 side with respect to the fourth extended portion 85 in the connection circuit RC3 in an installation state. One end of the third extended portion 84 is connected to the other end of the turnaround portion 83. The other end of the third extended portion 84 is connected to the fourth extended portion 85. The third extended portion 84 sends inflow refrigerant from one of the turnaround portion 83 and the fourth extended portion 85 to the other in an installation state.
The fourth extended portion 85 is a portion that mainly extends along the x direction (that is, the extending direction of the main pipe 70). The fourth extended portion 85 extends at right angles with respect to the extending direction of the third extended portion 84. The extending direction of the fourth extended portion 85 is the same as the extending direction of the first extended portion 81. The fourth extended portion 85 is a portion that extends between the third extended portion 84 and the indoor unit-side connection pipe CP2 to connect both in an installation state. The fourth extended portion 85 is located on the indoor unit 40 side with respect to the first extended portion 81, the second extended portion 82, the turnaround portion 83, and the third extended portion 84 in the connection circuit RC3 in an installation state. One end of the fourth extended portion 85 is connected to the other end of the third extended portion 84. The other end of the fourth extended portion 85 corresponds to the other end 802 of the branch pipe 80 and is connected to the associated indoor unit-side connection pipe CP2 in an installation state. The fourth extended portion 85 sends inflow refrigerant from one of the third extended portion 84 and the indoor unit-side connection pipe CP2 to the other in an installation state.
The connection pipe portion 90 (which corresponds to the “connection pipe” in the claims) connects the main pipe 70 and the branch pipe group 88 (branch pipes 80) in the second branch pipe unit 60. In one or more embodiments, as shown in
The branch pipe unit 50 is placed in the ceiling space SPa together with the outdoor unit-side connection pipe CP1 and the indoor unit-side connection pipes CP2. The ceiling space SPa is a narrow space formed between a top surface (ceiling space bottom surface C1) of the ceiling in the object space SP and a roof or floor upstairs (ceiling space top surface C2). The ceiling space SPa is a space of which the dimension in the horizontal direction is large and the dimension in the vertical direction is small.
In one or more embodiments, as shown in
The outdoor unit-side connection pipe CP1 extends along the major extending direction (rightward direction in
In
In
The upright portion V1 (second extended portion 82) functions as a trap portion T1 together with any one or some or all of the other portions (81, 83 to 85) included in the branch pipe 80. The trap portion T1 is a portion that, during normal cycle operation, when the indoor unit 40 in an operating state (operating indoor unit) and the indoor unit 40 in an operation stop state (hereinafter, referred to as “stopped indoor unit”) are mixedly present, suppresses the flow of refrigerant flowing from the connection pipe portion 90 to the stopped indoor unit side.
The second branch pipe unit 60 also functions as a “trap component” that makes up the trap portion T1. During normal cycle operation, refrigerant flows through the second branch pipe unit 60 in a mode as shown in
In the second branch pipe unit 60, during normal cycle operation, refrigerant in a gas-liquid two-phase state, flowing from the outdoor unit-side connection pipe CP1, flows into the main pipe 70. Refrigerant flowing into one end 701 of the main pipe 70 flows in the horizontal direction toward the other end 702 side (the indoor unit 40 side) and flows into the connection pipe portion 90. Refrigerant flowing into the first connection portion 901 of the connection pipe portion 90 diverges, flows to the second connection portions 902 side, and flows into the branch pipes 80. Refrigerant flowing into the branch pipe 80 communicating with the operating indoor unit flows from one end 801 side to the other end 802 side and then flows into the indoor unit-side connection pipe CP2. More specifically, refrigerant flowing along the horizontal direction in the first extended portion 81 flows into the second extended portion 82, flows along the upward direction, and flows into the turnaround portion 83. Refrigerant flowing into the turnaround portion 83 changes the flow direction, flows along the horizontal direction, changes the flow direction again, flows along the downward direction, and flows into the third extended portion 84. Refrigerant flowing into the third extended portion 84 flows along the downward direction and then flows into the fourth extended portion 85. Refrigerant flowing into the fourth extended portion 85 flows along the horizontal direction and flows into the indoor unit-side connection pipe CP2.
During normal cycle operation, when the operating indoor unit and the stopped indoor unit are mixedly present, refrigerant flows in a mode as shown in
During normal cycle operation, when the operating indoor unit and the stopped indoor unit are mixedly present, refrigerant in a gas-liquid two-phase state, flowing from the outdoor unit-side connection pipe CP1, flows into the main pipe 70. Refrigerant flowing into the main pipe 70 flows toward the indoor unit 40 side and flows into the connection pipe portion 90. Refrigerant flowing into the connection pipe portion 90 diverges and flows into the branch pipes 80. Refrigerant flowing into the branch pipe 80 communicating with the operating indoor unit (rear-side branch pipe 80a in
During normal cycle operation, when the operating indoor unit and the stopped indoor unit are mixedly present, the second branch pipe unit 60 functions as a “trap component” that provides the trap portion T1. The trap portion T1 suppresses the flow of refrigerant in a gas-liquid two-phase state, flowing into one ends 801 of the branch pipes 80, to the other ends 802 side by being filled with refrigerant in a gas state. In the refrigerant circuit RC, the position of the branch part BP made up of the second branch pipe unit 60 is selected as needed according to design specifications or an installation environment. In other words, the second branch pipe unit 60 is disposed at such an effective position that, during normal cycle operation, when the operating indoor unit and the stopped indoor unit are mixedly present, a shortage of the amount of circulating refrigerant in the operating indoor unit is suppressed by suppressing the flow of refrigerant to the stopped indoor unit side according to an installation mode of the indoor units 40 included in the air-conditioning system 100, an installation level or branching mode of the connection pipes in the refrigerant circuit RC.
In one or more embodiments, the second branch pipe unit 60 is disposed at the liquid-side branch part BPa (the liquid-side branch part BL1 shown in
In one or more embodiments, the first branch pipe 80a (see
An installation site of the second branch pipe unit 60 and a configuration mode and configuration part of each trap portion T1 are instructed through an installation manual, or the like, to a serviceman who performs installation.
The second branch pipe unit 60 is carried into an installation site in a state of being preassembled. The second branch pipe unit 60 is installed by being joined with other connection pipes (CP1, CP2) on an installation site. At this time, each branch pipe 80 is cut as needed so as to be adapted to an installation environment, or the like, and is then joined with the other connection pipes. An installation method for the second branch pipe unit 60 is instructed through an installation manual, or the like, to a serviceman who performs installation.
(7-1)
With the air-conditioning system 100 according to the above-described embodiments, a decrease in reliability is minimized in relation to performing gas-liquid two-phase transfer.
As for refrigerant that is transferred through a liquid-side refrigerant passage running between an outdoor unit and indoor units, it is possible to perform operation with a smaller amount of refrigerant filled (the amount of refrigerant filled in a refrigerant circuit) in the case of gas-liquid two-phase transfer to transfer refrigerant in a gas-liquid two-phase state as compared to the case of liquid transfer to transfer refrigerant in a liquid state, so employing the gas-liquid two-phase transfer is regarded as a method of achieving refrigerant saving. However, in the case where the amount of refrigerant filled is reduced by performing gas-liquid two-phase transfer, when some of the indoor units are in an operating state and the other indoor units are in an operation stop state (a state where an operation start command is not input or an operation suspension state, such as thermo-off), it is presumable that the amount of circulating refrigerant is not normally ensured in the indoor units in an operating state (operating indoor units) and, as a result, reliability decreases. In other words, since the amount of refrigerant filled when gas-liquid two-phase transfer is performed is less than the amount of refrigerant filled when liquid transfer is performed, when refrigerant to be fed to the operating indoor units flows from a branch part into indoor-side connection pipes that communicate with the indoor units in an operation stop state (non-operating indoor units), it is presumable that the amount of circulating refrigerant is not normally ensured in the operating indoor units and, as a result, reliability decreases.
The air-conditioning system 100 in the above-described embodiments is the air-conditioning system 100 that performs a refrigeration cycle in the refrigerant circuit RC, and includes the outdoor unit 10, the plurality of indoor units 40, and the liquid-side connection pipe La (which corresponds to the “connection pipe”). The liquid-side connection pipe La is disposed between the outdoor unit 10 and the indoor units 40 and at least forms a refrigerant passage through which refrigerant in a gas-liquid two-phase state flows. The liquid-side connection pipe La includes the liquid-side branch parts BPa (which correspond to the “branch portions”) and the trap portions T1. Each liquid-side branch part BPa includes the branch pipe group 88 (which corresponds to the “indoor-side pipe group”). The branch pipe group 88 is made up of the plurality of branch pipes 80 (which correspond to the “indoor-side pipes”) each communicating with any one or some of the indoor units 40. Each liquid-side branch part BPa diverges refrigerant flowing from the outdoor unit 10 side. Each trap portion T1 is provided in the associated branch pipe 80 (that is, each trap portion T1 is provided in at least any one of the branch pipes 80). The trap portions T1 are filled with refrigerant in a gas state.
With the air-conditioning system 100, in the air-conditioning system 100 in which refrigerant passes in a gas-liquid two-phase state through the liquid-side connection pipe La connecting the outdoor unit 10 and the indoor units 40, the trap portion T1 is provided in each of the branch pipes 80 included in the liquid-side connection pipe La (the liquid-side branch part BPa). Thus, in the case where the amount of refrigerant filled is reduced as compared to the existing one by performing gas-liquid two-phase transfer, when part of the indoor units (operating indoor units) are in an operating state and the other indoor units (stopped indoor units) are in an operation stop state, gas refrigerant is filled in the trap portions T1 (of the branch pipes 80 communicating with the stopped indoor units). As a result, the flow of refrigerant to the stopped indoor units is suppressed. Thus, a shortage of the amount of circulating refrigerant in the operating indoor units is avoided. Therefore, a decrease in reliability is minimized in relation to performing gas-liquid two-phase transfer.
(7-2)
The air-conditioning system 100 according to the above-described embodiments includes the outdoor second control valve 17 (which corresponds to the “pressure reducing valve”) that decompresses refrigerant such that refrigerant flowing from the outdoor unit 10 to the indoor units 40 passes through the liquid-side connection pipe La in a gas-liquid two-phase state. Thus, gas-liquid two-phase transfer can be simply realized.
(7-3)
In the air-conditioning system 100 according to the above-described embodiments, the indoor units 40 include the indoor units 40a, 40b (which correspond to the “first indoor units”) and the indoor units 40c, 40d (which correspond to the “second indoor units”) of which the installation level is lower than the installation level of the indoor units 40a, 40b. Each branch pipe group 88 (which corresponds to the “indoor-side pipe group”) includes the first branch pipe 80a (which corresponds to the “first indoor-side pipe”) and the second branch pipe 80b (which corresponds to the “second indoor-side pipe”). The first branch pipe 80a communicates with the indoor units 40a, 40b. The second branch pipe 80b communicates with the indoor units 40c, 40d. The trap portion T1 is provided in the second branch pipe 80b.
Thus, particularly, even when the indoor unit-side connection pipe CP2 communicating with the stopped indoor units communicates with the indoor unit-side connection pipe CP2 including a part of which the installation level is lower or the gradient is greater than the indoor unit-side connection pipe CP2 communicating with the operating indoor units, the flow of refrigerant in the second branch pipe 80b connected to the indoor unit-side connection pipe CP2 communicating with the stopped indoor units is suppressed. As a result, the flow of refrigerant to the stopped indoor units is appropriately suppressed.
(7-4)
In the air-conditioning system 100 according to the above-described embodiments, the liquid-side connection pipe La (which corresponds to the “connection pipe”) includes the plurality of liquid-side branch parts BPa (which correspond to the “branch portions”). The trap portion T1 is provided in each of the branch pipes 80 included in the liquid-side branch part BPa (liquid-side branch part BL1) closest to the outdoor unit 10. Thus, a shortage of the amount of circulating refrigerant in the operating indoor units is particularly avoided. In other words, in the case where a plurality of the liquid-side branch parts BPa is disposed, when refrigerant does not flow as assumed in the liquid-side branch part BL1 closest to the outdoor unit 10, the amount of refrigerant flowing to the stopped indoor units side (the branch pipe 80 communicating with the stopped indoor units) increases, with the result that the amount of circulating refrigerant in the operating indoor units particularly easily runs short. In other words, the trap portions T1 are disposed at the liquid-side branch part BL1 closest to the outdoor unit 10, so the flow of refrigerant into the stopped indoor units side is particularly suppressed, and a shortage of the amount of circulating refrigerant in the operating indoor units is particularly avoided.
(7-5)
In the air-conditioning system 100 according to the above-described embodiments, each trap portion T1 has the upright portion V1 (which corresponds to the “upward extended portion”). The upright portion V1 extends upward. The upright portion V1 is disposed in the associated branch pipe 80 (which corresponds to the “outdoor-side pipe”).
(7-6)
The air-conditioning system 100 according to the above-described embodiments includes the second branch pipe unit 60 (which corresponds to the “branch pipe unit”). The second branch pipe unit 60 is preassembled and connected to other pipes (here, the outdoor unit-side connection pipe CP1 and the indoor unit-side connection pipes CP2) on an installation site. The second branch pipe unit 60 is a component of the liquid-side branch part BPa. The second branch pipe unit 60 includes the main pipe 70 (which corresponds to the “outdoor-side pipe”) and the connection pipe portion 90 (which corresponds to the “connection pipe”). The main pipe 70 communicates with the branch pipe group 88 (which corresponds to the “indoor-side pipe group”). The main pipe 70 is located on the outdoor unit 10 side with respect to the branch pipe group 88 in the refrigerant circuit RC. The connection pipe portion 90 connects the main pipe 70 and the branch pipe group 88. The connection pipe portion 90 diverges refrigerant, flowing from the main pipe 70, to the branch pipe group 88. The extending direction of each of the main pipe 70 and the connection pipe portion 90 is a horizontal direction.
When the thus configured second branch pipe unit 60 is used, the trap portions T1 can be easily made on an installation site. Therefore, even when the liquid-side connection pipe La is installed in a narrow space like the ceiling space SPa, time and effort required for work to provide the trap portions T1 are reduced, so improvement in installability is facilitated.
The above-described embodiments may be modified as needed as shown in the following modifications. Each of the modifications may be applied in combination with another modification without any contradiction.
In the second branch pipe unit 60 in the above-described embodiments, each of the branch pipes 80 (the first branch pipe 80a and the second branch pipe 80b) included in the branch pipe group 88 includes the first extended portion 81, the second extended portion 82, the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85. In other words, in each of the branch pipes 80, the upright portion V1 (that is, the trap portion T1) is disposed. However, each of the branch pipes 80 does not necessarily need to include the first extended portion 81, the second extended portion 82, the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85. In other words, the upright portion V1 (that is, the trap portion T1) does not necessarily need to be disposed in each of the branch pipes 80.
For example, the second branch pipe unit 60 may be configured as in the case of a second branch pipe unit 60a (which corresponds to the “branch pipe unit”) shown in
The second branch pipe unit 60a includes a first branch pipe 80a′ and a second branch pipe 80b′ instead of the first branch pipe 80a and the second branch pipe 80b. The first branch pipe 80a′, different from the first branch pipe 80a, does not include the first extended portion 81, the second extended portion 82, the turnaround portion 83, or the third extended portion 84. In relation to this, in the first branch pipe 80a′, the upright portion V1 (that is, the trap portion T1) is not provided.
In the second branch pipe 80b′, the dimension in the y direction of the third extended portion 84 is greater than that of the second branch pipe 80b. In relation to this, in an installation state, the installation level of each of the fourth extended portion 85 and the indoor unit-side connection pipe CP2 connected to the fourth extended portion 85 is lower than that of the first branch pipe 80a′. In other words, the second branch pipe 80b′ is lower in installation level than the first branch pipe 80a′. In other words, the second branch pipe unit 60a is configured such that the trap portion T1 is provided in the branch pipe 80 (second branch pipe 80b′) including a portion of which the installation level is lower than that of the other branch pipe 80 (first branch pipe 80a′) of the branch pipe group 88 (which corresponds to the “indoor-side pipe group”).
In the case where the thus configured second branch pipe unit 60a is disposed instead of the second branch pipe unit 60 as well, when part of the indoor units 40 are in an operating state and the other indoor units 40 are in an operation stop state, the trap portion T1 (of the second branch pipe 80b′ communicating with the stopped indoor units) is filled with gas refrigerant. Particularly, in the case where the branch pipe 80 (here, the second branch pipe 80b′) communicating with the stopped indoor units is lower in installation level than the branch pipe 80 (here, the first branch pipe 80a′) communicating with the operating units or in the case where the branch pipe 80 (here, the second branch pipe 80b′) communicating with the stopped indoor units has a greater negative gradient portion than the branch pipe 80 (here, the first branch pipe 80a′) communicating with the operating units, the flow of refrigerant into the branch pipe 80 (second branch pipe 80b′) communicating with the stopped indoor units is appropriately suppressed. As a result, the flow of refrigerant to the stopped indoor units communicating with the second branch pipe 80b′ is suppressed. Thus, a shortage of the amount of circulating refrigerant in the operating indoor units communicating with the first branch pipe 80a′ is avoided.
When the second branch pipe unit 60a is used, the trap portion T1 can be easily made on an installation site. Therefore, even when the liquid-side connection pipe La is installed in a narrow space, time and effort required for work to provide a trap are reduced, so improvement in installability is facilitated.
The point that the upright portion V1 (that is, the trap portion T1) does not need to be disposed in each of the branch pipes 80 also applies to second branch pipe units 60b to 60g (see
The second branch pipe unit 60 may be configured as in the case of, for example, the second branch pipe unit 60b shown in
In the second branch pipe unit 60b, the branch pipe group 88 includes branch pipes 80A instead of the branch pipes 80. Each branch pipe 80A, different from the branch pipe 80, includes a first extended portion 81′, a second extended portion 82′, a turnaround portion 83′, a third extended portion 84′, and a fourth extended portion 85′. In the branch pipe 80A, the inclination angle of the second extended portion 82′ with respect to the x direction is less than that of the second extended portion 82 of the branch pipe 80. The inclination angle of the third extended portion 84′ with respect to the x direction is less than that of the third extended portion 84 of the branch pipe 80. In relation to this, the branch pipe 80A turns around in a spiral shape. In other words, the first extended portion 81′, second extended portion 82′, turnaround portion 83′, third extended portion 84′, and fourth extended portion 85′ of the branch pipe 80A are made so as to turn 360 degrees between one end 801 and the other end 802, and the trap portion T1 including the upright portion V1 is made in relation to this.
In the case where the thus configured second branch pipe unit 60b is disposed instead of the second branch pipe unit 60 as well, when part of the indoor units 40 are in an operating state and the other indoor units 40 are in an operation stop state, the trap portion T1 (of the branch pipe 80A communicating with the stopped indoor units) is filled with gas refrigerant. As a result, the flow of refrigerant to the stopped indoor units communicating with the branch pipe 80A is suppressed. Thus, a shortage of the amount of circulating refrigerant in the operating indoor units can be avoided.
When the second branch pipe unit 60b is used, the trap portions T1 can be easily made on an installation site. Therefore, even when the liquid-side connection pipe La is installed in a narrow space, time and effort required for work to provide a trap are reduced, so improvement in installability is facilitated.
The second branch pipe unit 60 may be configured as in the case of, for example, the second branch pipe unit 60c shown in
The second branch pipe unit 60c includes a connection pipe portion 90A instead of the connection pipe portion 90. The connection pipe portion 90A, different from the connection pipe portion 90, is disposed so as to extend in the y direction (that is, a direction that intersects with the extending direction of the main pipe 70 and in an upward direction in an installation state). In other words. the connection pipe portion 90A is connected to the main pipe 70 and the branch pipe group 88 in substantially a U-shape or substantially a C-shape when viewed in the x direction.
In the second branch pipe unit 60c, the branch pipe group 88 includes branch pipes 80B instead of the branch pipes 80. Each branch pipe 80B, different from the branch pipe 80, does not include the first extended portion 81. The branch pipe 80B includes a second extended portion 82a of which the dimension in the y direction is less than that of the second extended portion 82, instead of the second extended portion 82.
In the second branch pipe unit 60c, the upright portions V1 and the trap portions T1 are made up of the connection pipe portion 90A together with the branch pipes 80B.
In other words, in the second branch pipe unit 60c, the extending direction of the main pipe 70 (which corresponds to the “outdoor-side pipe”) is the x direction (a horizontal direction in an installation state), the extending direction of the connection pipe portion 90A (which corresponds to the “connection pipe”) is the y direction (a vertical direction in an installation state, and each upright portion V1 (which corresponds to the “upward extended portion”) is disposed over the connection pipe portion 90A and the associated branch pipes 80B (which correspond to the “indoor-side pipes”). When the thus configured second branch pipe unit 60c is disposed instead of the second branch pipe unit 60 as well, similar advantageous effects to those according to the above-described embodiments are obtained. In other words, when the trap portions T1 are made up of the branch pipes and the connection pipe portion as well, a decrease in reliability related to two-phase transfer is minimized.
When the second branch pipe unit 60c is used, the trap portions T1 can be easily made on an installation site. Therefore, even when the liquid-side connection pipe La is installed in a narrow space, time and effort required for work to provide a trap are reduced, so improvement in installability is facilitated.
The second branch pipe unit 60c may be configured as in the case of, for example, the second branch pipe unit 60d shown in
The second branch pipe unit 60d includes a main pipe 70A instead of the main pipe 70. The main pipe 70A includes a first main pipe portion 71 extending along the x direction (the “horizontal direction” in an installation state) and a second main pipe portion 72 extending along the y direction (the “vertical direction” in an installation state). A terminal of the first main pipe portion 71 is one end 701′ of the main pipe 70A, and is connected to the outdoor unit-side connection pipe CP1 in an installation state. A distal end of the first main pipe portion 71 is connected to a terminal of the second main pipe portion 72. The second main pipe portion 72 is located between the first main pipe portion 71 and a set of the connection pipe portion 90A and the second extended portions 82a. A distal end of the second main pipe portion 72 is the other end 702′ of the main pipe 70A and is connected to the connection pipe portion 90A. In other words, the main pipe 70A extends from one end 701′ along the x direction, then extends in the y direction, and is connected to the connection pipe portion 90A. In relation to this, in the second branch pipe unit 60d, the upright portion V1 and the trap portions T1 are made up of the branch pipes 80B, the connection pipe portion 90A, and the main pipe 70A (second main pipe portion 72).
In other words, in the second branch pipe unit 60d, the extending direction of each of the main pipe 70A (which corresponds to the “outdoor-side pipe”) and the connection pipe portion 90A (which corresponds to the “connection pipe”) is the y direction (the vertical direction in an installation state), and the upright portion V1 (which corresponds to the “upward extended portion”) is disposed over the main pipe 70A, the connection pipe portion 90A, and the associated branch pipes 80B (which correspond to the “indoor-side pipes”). When the thus configured second branch pipe unit 60d is disposed instead of the second branch pipe unit 60 as well, similar advantageous effects to those according to the above-described embodiments are obtained. In other words, when the trap portions T1 are made up of the branch pipes, the connection pipe portion, and the main pipe as well, a decrease in reliability related to two-phase transfer is minimized. When the second branch pipe unit 60d is used, the trap portions T1 can be easily made on an installation site. Therefore, even when the liquid-side connection pipe La is installed in a narrow space, time and effort required for work to provide a trap are reduced, so improvement in installability is facilitated.
In the second branch pipe unit 60d, the first main pipe portion 71 in the main pipe 70A may be omitted as in the case of a second branch pipe unit 60d′ shown in
The second branch pipe unit 60d may be configured as in the case of, for example, the second branch pipe unit 60e shown in
The second branch pipe unit 60e includes a main pipe 70B instead of the main pipe 70A and includes a connection pipe portion 90B instead of the connection pipe portion 90A.
The main pipe 70B includes a third main pipe portion 73 extending along the x direction (horizontal direction in an installation state) and then extending along the y direction (downward direction in an installation state), and a fourth main pipe portion 74 extending along the y direction (downward direction in an installation state) on the branch pipe group 88 side with respect to the third main pipe portion 73. A terminal of the third main pipe portion 73 is one end 701′ of the main pipe 70B, and is connected to the outdoor unit-side connection pipe CP1 in an installation state. A distal end of the third main pipe portion 73 is connected to a terminal of the fourth main pipe portion 74. A distal end of the fourth main pipe portion 74 is the other end 702″ of the main pipe 70B and is connected to the connection pipe portion 90B (between both end portions 902′ of the connection pipe portion 90B). In other words, the main pipe 70B extends from one end 701′ along the x direction, then extends in the y direction, and is connected to the connection pipe portion 90B at the other end 702″.
In the second branch pipe unit 60e, the upright portions V1 and the trap portions T1 are made up of the branch pipes 80B and the connection pipe portion 90B (connection pipe extended portions 91).
In other words, in the second branch pipe unit 60e, the main pipe 70B (which corresponds to the “outdoor-side pipe”) extends along the y direction (downward direction in an installation state), the connection pipe portion 90B (which corresponds to the “connection pipe”) includes the connection pipe extended portions 91 (which correspond to the “turnaround portions”) that turn refrigerant, flowing from the main pipe 70B, around to the upward direction, and the upright portion V1 (which corresponds to the “upward extended portion”) is disposed over the connection pipe portion 90B and the associated branch pipes 80B (which correspond to the “indoor-side pipes”). When the thus configured second branch pipe unit 60e is disposed instead of the second branch pipe unit 60 as well, similar advantageous effects to those according to the above-described embodiments are obtained. In other words, when the trap portions T1 are made up of the branch pipes and the connection pipe portion as well, a decrease in reliability related to two-phase transfer is minimized.
When the second branch pipe unit 60e is used, the trap portions T1 can be easily made on an installation site. Therefore, even when the liquid-side connection pipe La is installed in a narrow space, time and effort required for work to provide a trap are reduced, so improvement in installability is facilitated.
The second branch pipe unit 60e may be configured as in the case of, for example, the second branch pipe unit 60f shown in
In the second branch pipe unit 60f, different from the second branch pipe unit 60e, the connection pipe portion 90B is omitted. The second branch pipe unit 60f includes a main pipe 70B′ instead of the main pipe 70B. The main pipe 70B′ includes a fifth main pipe portion 75 in addition to the third main pipe portion 73 and the fourth main pipe portion 74. The fifth main pipe portion 75 is a portion that extends in the y direction (downward direction in an installation state) on the branch pipe group 88 side with respect to the third main pipe portion 73, then extends along the x direction and/or the z direction (horizontal direction in an installation state) and diverges according to the number of the branch pipes 80B included in the branch pipe group 88, turn around to the y direction (upward direction in an installation state) at the branched end portions, and are connected to the second extended portions 82a of the branch pipes 80B. In the second branch pipe unit 60f, the fifth main pipe portion 75 includes a portion extending along the x direction.
The fourth main pipe portion 74 is located on the outdoor unit 10 side with respect to the fifth main pipe portion 75 in the liquid-side connection circuit RC3a in an installation state. In the second branch pipe unit 60f, in an installation state, refrigerant flowing from the outdoor unit 10 to the indoor units 40 flows along the downward direction in the fourth main pipe portion 74.
With the thus configured second branch pipe unit 60f as well, similar advantageous effects to those in the case where the second branch pipe unit 60e is used.
The second branch pipe unit 60e may be configured as in the case of, for example, the second branch pipe unit 60g shown in
The second branch pipe unit 60g includes a main pipe 70C instead of the main pipe 70B. In the main pipe 70C, different from the main pipe 70B, the third main pipe portion 73 is omitted. In relation to this, a terminal of the fourth main pipe portion 74 is one end 701′ of the main pipe 70C, and is connected to the outdoor unit-side connection pipe CP1 in an installation state.
In the second branch pipe unit 60g, as well as the second branch pipe unit 60e, the upright portions V1 and the trap portions T1 are made up of the branch pipes 80B and the connection pipe portion 90B. When the second branch pipe unit 60g is disposed instead of the second branch pipe unit 60 as well, similar advantageous effects to those according to the above-described embodiments are obtained. In other words, when the trap portions T1 are made up of the branch pipes, the connection pipe portion, and the main pipe as well, a decrease in reliability related to two-phase transfer is minimized
In the above-described embodiments, the case where the liquid-side branch part BL1 that is the liquid-side branch part BPa closest to the outdoor unit 10 is made up of the second branch pipe unit 60 is described. However, the branch part BP made up of the second branch pipe unit 60 just needs to be selected as needed in light of the necessity of making a trap portion T1 according to design specifications or an installation environment. For example, any one or some or all of the liquid-side branch parts BL2, BL3, BL4, BL5, BL6, and the like, shown in
The second extended portion 82 does not necessarily need to extend at right angles with respect to the extending direction of the first extended portion 81 or the main pipe 70. In other words, the inclination angle of the second extended portion 82 with respect to the extending direction of the first extended portion 81 or the main pipe 70 may be an angle less than 90 degrees. For example, the second extended portion 82 may extend along the y direction at an inclination angle of 30 degrees to 60 degrees with respect to the extending direction of the first extended portion 81 or the main pipe 70.
In the above-described embodiments, the second branch pipe unit 60 is made by joining the separate main pipe 70, connection pipe portion 90, and branch pipes 80 with one another. However, the second branch pipe unit 60 may be made by integrally forming some or all of the main pipe 70, the connection pipe portion 90, and the branch pipes 80. For example, the second branch pipe unit 60 may be made by bending a single pipe. Alternatively, for example, the second branch pipe unit 60 may be made by joining a plurality of pipes with one another.
The mode of configuration of each of the main pipe 70, connection pipe portion 90, and branch pipes 80 included in the second branch pipe unit 60 may be selected as needed. In other words, each of the main pipe 70, connection pipe portion 90, and branch pipes 80 may be made by bending a single pipe or may be made by joining a plurality of pipes with one another.
In the above-described embodiments, the case where the second branch pipe unit 60 makes up the whole of the predetermined branch part BP is described. However, the second branch pipe unit 60 does not necessarily need to make up the whole of the branch part BP and may make up only part of the branch part BP. In other words, the second branch pipe unit 60 may make up the branch part BP together with another pipe(s) (for example, any one or some or all of the outdoor unit-side connection pipe CP1 and the indoor unit-side connection pipes CP2, or another pipe unit).
In the above-described embodiments, the case where the second branch pipe unit 60 is carried to an installation site in a preassembled state is described. However, the configuration is not limited thereto. The second branch pipe unit 60 may be assembled by joining or cutting parts on an installation site. For example, the second branch pipe unit 60 may be assembled by joining any one or some or all of the main pipe 70, connection pipe portion 90, and branch pipes 80 in a state of being separated from other portions, with the other portions on an installation site. Alternatively, for example, the second branch pipe unit 60 may be assembled by cutting any one or some or all of the main pipe 70, connection pipe portion 90, and branch pipes 80 on an installation site as needed.
Alternatively, for example, any one or some of all of the portions included in the main pipe 70 may be assembled by being joined with another one of the parts included in the main pipe 70 on an installation site. Alternatively, for example, any one or some or all of the portions included in the main pipe 70 may be assembled by cutting on an installation site as needed.
Alternatively, for example, any one or some or all of the portions included in the connection pipe portion 90 may be assembled by being joined with another portion included in the main pipe 70 on an installation site. Alternatively, for example, any one or some or all of the portions included in the connection pipe portion 90 may be assembled by cutting on an installation site as needed.
Alternatively, for example, any one or some or all of the portions (for example, 81 to 85) included in each branch pipe 80 may be assembled by being joined with another portion included in the main pipe 70 on an installation site. Alternatively, for example, any one or some or all of the portions (for example, 81 to 85) included in each branch pipe 80 may be assembled by cutting on an installation site as needed.
In the above-described embodiments, the case where each branch pipe 80 is made up of the first extended portion 81, the second extended portion 82, the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85 is described. However, the mode of configuration of each branch pipe 80 is not necessarily limited thereto, and modification is applicable as needed without any contradiction from the operation and advantageous effects in the above-described embodiments (that is, when part of the indoor units 40 are in an operating state and the other indoor units 40 are in an operation stop state, the trap portion T1 of the branch pipe 80 communicating with the stopped indoor units is filled with gas refrigerant). For example, each branch pipe 80 does not need to include any one or some or all of the first extended portion 81, the turnaround portion 83, the third extended portion 84, and the fourth extended portion 85. Alternatively, for example, each branch pipe 80 may additionally include a portion other than the first extended portion 81, the turnaround portion 83, the third extended portion 84, or the fourth extended portion 85.
In the above-described embodiments, the case where each branch pipe 80 has a size of greater than or equal to two eighths and less than or equal to six eighths is described. In terms of this point, the inside diameter and/or outside diameter of the branch pipe 80 does not necessarily need to be uniform from one end to the other end and may have a portion that partially expands or contracts.
In the above-described embodiments, the x direction corresponds to the right-left direction in an installation state, and the z direction corresponds to the front-rear direction in an installation state. However, the configuration is not limited thereto, and the x direction may correspond to the front-rear direction in an installation state, and the z direction may correspond to the right-left direction in an installation state.
The installation mode of the second branch pipe unit 60 shown in
In the above-described embodiments, in the second branch pipe unit 60, the branch pipe group 88 includes the two branch pipes 80 (80a, 80b). Alternatively, the branch pipe group 88 may include three or more branch pipes 80. In this case, the upright portion V1 (which corresponds to the “upward extended portion”) just needs to be provided in a predetermined one or more of the branch pipes 80 as needed according to design specifications or an installation environment.
The mode of configuration of the refrigerant circuit RC in the above-described embodiments is not necessarily limited to the mode shown in
For example, the outdoor first control valve 16 is not necessarily required and may be omitted as needed. In this case, the outdoor second control valve 17 may be caused to provide the function of the outdoor first control valve 16 during reverse cycle operation.
For example, the outdoor second control valve 17 is not necessarily required to be disposed in the outdoor unit 10 and may be disposed outside the outdoor unit 10 (for example, in the liquid-side connection pipe La).
For example, the indoor expansion valve 41 is not necessarily required to be disposed in the indoor unit 40 and may be disposed outside the indoor unit 40 (for example, in the liquid-side connection pipe La).
For example, the subcooler 15 or the outdoor third control valve 18 is not necessarily required and may be omitted as needed. Alternatively, a device not shown in
Alternatively, for example, in the refrigerant circuit RC, a refrigerant passage switching unit that switches the flow of refrigerant into each indoor unit 40 may be disposed between the outdoor unit 10 and each indoor unit 40 in order to make it possible to individually perform normal cycle operation and reverse cycle operation for each indoor unit 40.
In the air-conditioning system 100 according to the above-described embodiments, the plurality of (four or more) indoor units 40 is connected in series or parallel to the single outdoor unit 10 by the connection pipes (Ga, La). In terms of this point, the number of the outdoor units 10 and/or the number of the indoor units 40 and the mode of connection may be modified as needed according to an installation environment or design specifications. For example, a plurality of the outdoor units 10 may be arranged in series or parallel with each other.
In the above-described embodiments, R32 is used as a refrigerant that circulates through the refrigerant circuit RC. Alternatively, a refrigerant that is used in the refrigerant circuit RC is not limited and may be another refrigerant. For example, in the refrigerant circuit RC, HFC-series refrigerant, such as R407C and R410A, may be used.
In the above-described embodiments, ideas according to the present invention are applied to the air-conditioning system 100. However, not limited thereto, the ideas according to the present invention may also be applied to another refrigeration apparatus (for example, a water heater, a heat pump chiller, or the like) having a refrigerant circuit.
In the above-described embodiments, the second branch pipe unit 60 is applied to the air-conditioning system 100 that performs gas-liquid two-phase transfer during normal cycle operation. However, the second branch pipe unit 60 is not necessarily avoided to be applied to an air-conditioning system that performs liquid transfer.
In the above-described embodiments, in the air-conditioning system 100, the outdoor second control valve 17 is used as a device that realizes gas-liquid two-phase transfer. Alternatively, gas-liquid two-phase transfer may be realized by using another device instead of the outdoor second control valve 17 or in addition to the outdoor second control valve 17. In other words, the outdoor second control valve 17 is not necessarily required and may be omitted as needed.
For example, gas-liquid two-phase transfer may be performed by controlling the opening degree of the outdoor first control valve 16. Alternatively, for example, another control valve not shown in
In this case, the pipe length (particularly, the length from the outdoor unit 10 to the trap portion T1) of the liquid-side connection pipe La is recorded in advance, and the status of refrigerant may be controlled such that refrigerant flows in a gas-liquid two-phase state through the liquid-side connection pipe La according to the pipe length. In other words, when the pipe length (particularly, the length from the outdoor unit 10 to the trap portion T1) of the liquid-side connection pipe La is known, the status (pressure or temperature) of refrigerant flowing out from the outdoor unit 10 may be controlled based on a pressure loss, or the like, in the liquid-side connection pipe La so as to be in a gas-liquid two-phase state on the upstream side of the trap portion T1.
(9)
The present invention is usable in an air-conditioning system.
Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims.
PTL 1 International Publication No. 2015/029160
Number | Date | Country | Kind |
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2017-190406 | Sep 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/027340 | 7/20/2018 | WO | 00 |