JP7244166B2 - piping unit or air conditioning system - Google Patents

Description

The present invention relates to piping units or air conditioning systems.

Conventionally, an air conditioning system having an outdoor unit and a plurality of indoor units is known. For example, Patent Document 1 (International Publication No. 2015/029160) discloses an air conditioning system in which one outdoor unit and a plurality of indoor units are connected via refrigerant communication pipes. In Patent Document 1, refrigerant communication pipes are branched from the refrigerant communication pipe according to the number of indoor units. In Patent Document 1, gas-liquid two-phase transport is performed in which the refrigerant is transported in a gas-liquid two-phase state with respect to the refrigerant transported in the liquid-side refrigerant flow path extending between the outdoor unit and the indoor unit.

Here, since the liquid-side refrigerant flow path between the outdoor unit and the indoor unit is configured by a refrigerant communication pipe, there may be cases where a trap needs to be provided in the refrigerant communication pipe depending on the design specifications and installation environment.

For example, a refrigerant communication pipe usually includes a number of branch pipes corresponding to the number of indoor units. If there are restrictions on the construction of the refrigerant communication pipes due to (beams in the space above the ceiling, etc.), some branch pipes may have a lower installation height than other branch pipes or may have a steep downward slope. In such a case, it may be necessary to provide a trap in the refrigerant communication pipe in order to suppress the drift and stagnation of the refrigerant.

Further, for example, when performing gas-liquid two-phase transfer as in Patent Document 1, since the amount of refrigerant charged is smaller than usual, the branch pipe communicating with the indoor unit in the operation stopped state (stopped indoor unit) is in a liquid state. It is conceivable that the refrigerant that is not filled with refrigerant and should be sent to the operating indoor unit (operating unit) flows from the branch portion into the branch pipe that communicates with the stopped indoor unit. In particular, when the branch pipe communicating with the stop indoor unit is installed at a lower height than the branch pipe communicating with the operating unit or has a steep downward slope, the refrigerant tends to flow into the branch pipe communicating with the stop indoor unit. For this reason, when performing gas-liquid two-phase transfer, in order to prevent the situation in which the refrigerant flows in and stays in the stopped indoor unit, and the refrigerant circulation amount in the operating unit is not ensured normally, a trap is placed in the refrigerant communication pipe. may need to be provided.

On the other hand, such a refrigerant communication pipe is usually installed in a narrow space such as a ceiling space where it is constructed by a serviceman at a construction site. For this reason, the labor and time required to install the trap at the construction site tend to be large, and there are cases where the workability is not excellent. To provide a piping unit or an air conditioning system that promotes workability improvement.

The piping unit is connected to the refrigerant communication pipe, forms a liquid-side refrigerant flow path together with the refrigerant communication pipe, and branches or merges the refrigerant, and includes a plurality of branch pipes and a main pipe. The refrigerant communication pipe forms a liquid-side refrigerant channel between the outdoor unit and the plurality of indoor units. The main pipe communicates with each branch pipe. The main pipe forms a channel for the refrigerant flowing to or from each branch pipe. In the installed state, the main pipe is located closer to the outdoor unit than the branch pipe in the liquid-side refrigerant channel. The main pipe includes a first portion. The first portion extends along the first direction. At least one branch includes a second portion. The second portion extends along the second direction. The second direction is a direction crossing the first direction. The first direction is the horizontal direction in the installed state. The second direction is the vertical direction in the installed state.

In the piping unit, the liquid-side refrigerant channel is formed together with the refrigerant communication pipe between the outdoor unit and the plurality of indoor units, and the main pipe includes a first portion extending along the first direction (horizontal direction in the installed state), The at least one branch pipe includes a second portion extending along a second direction (the vertical direction in the installed state) intersecting the first direction. Thereby, in the installed state, the second portion of the branch pipe extends along the vertical direction and can function as a trap. That is, the trap can be easily constructed by appropriately connecting the main pipe and branch pipes of the pipe unit functioning as a "trap component" to the refrigerant communication pipe at the construction site. Therefore, in the case where it is necessary to provide a trap in the refrigerant communication pipe that forms the liquid-side communication channel, the work of bending the pipe to form the trap and connecting the pipe can be reduced at the construction site. As a result, even when the refrigerant communication pipe is installed in a narrow space, the labor and time required for installing the trap can be reduced. Therefore, the improvement of enforceability is promoted.

Here, "extending along the first direction" means not only the state in which the extending direction necessarily matches the first direction (horizontal direction in the installed state), but also the extending direction is slightly inclined with respect to the first direction. Also includes state. For example, a state of being inclined within a range of a predetermined angle (for example, 30 degrees) with respect to the first direction is interpreted as "extending along the first direction".

In addition, "extending along the second direction" means not only the state in which the extending direction necessarily coincides with the second direction (the vertical direction in the installed state), but also the state in which the extending direction is slightly inclined with respect to the second direction. Also includes For example, a state of being inclined and extending within a range of a predetermined angle (for example, 30 degrees) with respect to the second direction is interpreted as "extending along the second direction."

In the piping unit, preferably the at least one branch pipe further includes a third portion and a turn-up portion. The third portion is positioned closer to the indoor unit than the second portion in the liquid-side refrigerant channel in the installed state. The third portion extends along the second direction. The folded portion is positioned between the second portion and the third portion in the liquid-side refrigerant channel in the installed state. The folded portion connects the second portion and the third portion.

In the piping unit, preferably the at least one branch pipe further comprises a fourth portion. The fourth portion is positioned closer to the indoor unit than the third portion in the liquid-side refrigerant channel in the installed state. The fourth portion extends along the first direction. This makes it possible to connect the end of the main pipe on the side of the outdoor unit and the end of the branch pipe on the side of the indoor unit to the liquid-side communication pipe extending horizontally at the construction site. For this reason, when the refrigerant communication pipe is installed in a narrow space, the labor and time required for the operation of installing the trap are further reduced, and the workability is further improved.

In the piping unit, preferably the at least one branch pipe further comprises a fifth portion. The fifth portion is positioned closer to the outdoor unit than the second portion in the liquid-side refrigerant channel in the installed state. The fifth portion extends along the first direction.

In the piping unit, preferably the main pipe further includes a sixth portion. The sixth portion is located between the first portion and the second portion. The sixth portion extends along the second direction.

In the piping unit, preferably the main pipe further comprises a seventh portion. The seventh portion is positioned closer to the outdoor unit than the first portion in the liquid-side refrigerant channel in the installed state. The seventh portion extends along the second direction. The refrigerant flowing from the outdoor unit to the indoor unit flows downward in the seventh portion in the installed state. In the installed state, the refrigerant flowing from the outdoor unit to the indoor unit flows upward in the second portion.

The piping unit preferably further comprises a connecting pipe. Each branch includes a second portion. The connection pipe connects the ends of the second portions on the outdoor unit side. The main pipe further includes an eighth portion. The eighth portion is positioned closer to the indoor unit than the first portion in the liquid-side refrigerant channel in the installed state. The connection pipe extends along the first direction. The connecting pipe has multiple ends. The end of the connecting tube is connected to any second portion. The eighth portion extends along the second direction. The eighth portion is connected between the ends of the connection pipe at the end on the indoor unit side. The refrigerant flowing from the outdoor unit to the indoor unit flows downward in the eighth portion in the installed state. In the installed state, the refrigerant flowing from the outdoor unit to the indoor unit flows upward in the second portion.

Preferably, in the piping unit, at least one branch pipe is folded back to form a spiral.

In the piping unit, the first direction and the second direction preferably intersect substantially at right angles. It should be noted that the term "substantially perpendicularly intersect" here means not only the case where the first direction and the second direction intersect at 90 degrees, but also the case where the first direction and the second direction are slightly inclined with respect to 90 degrees. including crossing Specifically, when the first direction and the second direction intersect within a predetermined angle range (for example, 60 degrees or more and 120 degrees or less), this is interpreted as "substantially perpendicular intersection".

In the piping unit, preferably the size of the branch pipe is 2 minutes or more and 6 minutes or less. Here, "2 minutes" and "6 minutes" are the nominal diameters of pipe sizes that are commonly used. Specifically, "two minutes" here is 1/4 inch with an outer diameter of 6.35 mm (or approximate) and an inner diameter of 4.75 mm (or approximate). Also, "six minutes" here is 3/4 inch with an outer diameter of 19.05 mm (or an approximate value) and an inner diameter of 16.95 mm (or an approximate value).

In the piping unit, preferably, the refrigerant flowing from the outdoor unit to the indoor unit through the liquid-side refrigerant channel flows into the liquid-side refrigerant channel in a gas-liquid two-phase state.

An air conditioning system includes an outdoor unit, a plurality of indoor units, a refrigerant communication pipe, and a pipe unit.

Schematic configuration diagram of an air conditioning system. Schematic application diagram of an air conditioning system. FIG. 2 is a schematic diagram showing an example of a refrigeration cycle during normal cycle operation (during normal control); The schematic block diagram of a 1st branch pipe unit. The schematic block diagram of a 2nd branch pipe unit. The schematic diagram which showed an example of the installation aspect of a 1st branch pipe unit. The schematic diagram which showed an example of the installation aspect of a 2nd branch pipe unit. FIG. 4 is a schematic diagram showing an example of refrigerant flow in the second branch pipe unit during normal cycle operation. FIG. 4 is a schematic diagram showing an example of the flow of refrigerant when the operating indoor unit and the stopped indoor unit coexist during normal cycle operation. 4 is a schematic configuration diagram of a second branch pipe unit according to Modification 1. FIG. FIG. 8 is a schematic configuration diagram of a second branch pipe unit according to Modification 2; FIG. 11 is a schematic configuration diagram of a second branch pipe unit according to Modification 3; FIG. 11 is a schematic configuration diagram of a second branch pipe unit according to Modification 4; FIG. 11 is a schematic configuration diagram of another example of the second branch pipe unit according to Modification 4; FIG. 11 is a schematic configuration diagram of a second branch pipe unit according to Modification 5; FIG. 12 is an enlarged view of the periphery of the connection pipe portion in the second branch pipe unit according to Modification 5; FIG. 12 is an enlarged view of the periphery of the connection pipe portion in the second branch pipe unit according to Modification 6; FIG. 11 is a schematic configuration diagram of a second branch pipe unit according to Modification 7;

Hereinafter, an air conditioning system 100 and a second branch pipe unit 60 (piping unit) according to an embodiment of the present disclosure will be described. It should be noted that the following embodiments are specific examples, and do not limit the technical scope, and can be modified as appropriate without departing from the scope of the invention. In the following description, directions such as up, down, left, right, front, and back are the directions shown in FIGS. 2 and 6-9.

In the present disclosure, the “horizontal direction” includes the left-right direction and the front-rear direction. Moreover, the "horizontal direction" includes not only a completely horizontal direction but also a direction inclined within a range of a predetermined angle (for example, 30 degrees) with respect to the horizontal line.

In the present disclosure, the “vertical direction” includes the vertical direction. Moreover, the "vertical direction" includes not only a completely vertical direction but also a direction inclined within a range of a predetermined angle (for example, 45 degrees) with respect to the vertical line.

In the present disclosure, "perpendicular" includes not only a perfect right angle (90 degrees) but also a "substantially right angle" (an angle that increases or decreases within a predetermined angle (eg, 30 degrees) with respect to 90 degrees.

In the present disclosure, the “operation stop state” includes a state in which operation is stopped due to an input of a stop command, a state in which operation is stopped due to a power cutoff, and a state in which operation is stopped without input of an operation start command. It includes not only the state in which the operation is not performed, but also the state in which the operation is temporarily suspended due to the thermostat being turned off.

In the present disclosure, for "joining" and "connecting" of each part, "methods" are appropriately selected according to the installation environment and design specifications. The "method" is not particularly limited, but brazing connection, flare connection, flange connection, or the like is assumed, for example.

(1) Overview of Air Conditioning System 100 FIG. 1 is a schematic configuration diagram of the air conditioning system 100. As shown in FIG. FIG. 2 is a schematic application diagram of the air conditioning system 100 . The air-conditioning system 100 is installed in a building, a factory, or the like, and realizes air conditioning of a target space SP. In this embodiment, as shown in FIG. 2, the air conditioning system 100 air-conditions rooms (target spaces SP1, SP2, etc.) in a building B1 having multiple floors. Note that the number of floors, the number of rooms, etc. of the building B1 can be changed as appropriate. The air conditioning system 100 performs cooling, heating, and the like of the target space SP by performing a refrigeration cycle in the refrigerant circuit RC.

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, . It has a side communication pipe La (corresponding to a “refrigerant communication pipe” described in claims) and a gas side communication pipe Ga.

In the air conditioning system 100, the refrigerant circuit RC is configured by connecting the outdoor unit 10 and each indoor unit 40 with the liquid-side communication pipe La and the gas-side communication pipe Ga. The air conditioning system 100 performs a vapor compression refrigeration cycle in which the refrigerant enclosed in the refrigerant circuit RC is compressed, cooled or condensed, decompressed, heated or evaporated, and then compressed again. The refrigerant with which the refrigerant circuit RC is filled is not particularly limited, but R32, for example, is employed.

The refrigerant circuit RC mainly includes an outdoor circuit RC1 configured in the outdoor unit 10, an indoor circuit RC2 configured in each indoor unit 40, the outdoor circuit RC1, and each indoor circuit RC2. A communication circuit RC3 is included. Further, the communication circuit RC3 includes a liquid-side communication circuit RC3a (corresponding to the "liquid-side refrigerant flow path" described in the claims) that functions as a liquid-side refrigerant flow path between the outdoor unit 10 and the indoor unit 40. and a gas-side communication circuit RC3b functioning as a gas-side refrigerant flow path flowing between the outdoor unit 10 and the indoor unit 40.

In the air conditioning system 100, gas-liquid two-phase transport is performed in which the refrigerant is transported in a gas-liquid two-phase state in the liquid-side connecting pipe La extending between the outdoor unit 10 and the indoor unit 40. FIG. More specifically, with respect to the refrigerant conveyed in the liquid-side communication pipe La extending between the outdoor unit 10 and the indoor unit 40, compared to the case of being conveyed in the liquid state, the case of being conveyed in the gas-liquid two-phase state In view of the fact that the air conditioning system 100 can operate with a small amount of charged refrigerant while suppressing a decrease in performance, the air-conditioning system 100 does not require gas-liquid two-phase transportation in the liquid-side communication circuit RC3a in order to save refrigerant. configured to take place. The air conditioning system 100 has a “pressure reducing valve” (outdoor second control valve 17 described later) for reducing the pressure of the refrigerant in the outdoor unit 10 in order to realize gas-liquid two-phase transportation.

The heat load here is the heat load that is required to be processed by the indoor unit 40 (operating indoor unit) during operation, for example, the set temperature set in the operating indoor unit, the operating indoor unit Based on any/all of the temperature in the target space SP, the amount of refrigerant circulation, the rotation speed of the indoor fan 45, the rotation speed of the compressor 11, the capacity of the outdoor heat exchanger 14, the capacity of the indoor heat exchanger 42, etc. Calculated.

(1-1) Outdoor unit 10
The outdoor unit 10 is installed outdoors, such as on the roof of a building or on a veranda, or outdoors (outside the target space SP), such as in a basement. The outdoor unit 10 is connected to a plurality of indoor units 40 via a liquid-side connecting pipe La and a gas-side connecting pipe Ga, and constitutes part of the refrigerant circuit RC (outdoor circuit RC1).

The outdoor unit 10, as equipment constituting the outdoor circuit RC1, mainly includes a plurality of refrigerant pipes (first pipe P1-twelfth pipe P12), a compressor 11, an accumulator 12, a four-way switching valve 13, The outdoor heat exchanger 14, the supercooler 15, the first outdoor control valve 16, the second outdoor control valve 17, the third outdoor control valve 18, the liquid-side closing valve 19, and the gas-side closing valve 20. ,have.

The first pipe P<b>1 connects the gas side shutoff valve 20 and the first port of the four-way switching valve 13 . The second pipe P2 connects the inlet port of the accumulator 12 and the second port of the four-way switching valve 13 . The third pipe P3 connects the outlet port of the accumulator 12 and the suction port of the compressor 11 . A fourth pipe P<b>4 connects the discharge port of the compressor 11 and the third port of the four-way switching valve 13 . The fifth pipe P5 connects the fourth port of the four-way switching valve 13 and the gas inlet/outlet of the outdoor heat exchanger 14 . The sixth pipe P<b>6 connects the liquid side inlet/outlet of the outdoor heat exchanger 14 and one end of the first outdoor control valve 16 . The seventh pipe P7 connects the other end of the first outdoor control valve 16 and one end of the main flow path 151 of the supercooler 15 . The eighth pipe P8 connects the other end of the main flow path 151 of the subcooler 15 and one end of the second outdoor control valve 17 . The ninth pipe P9 connects the other end of the second outdoor 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 third outdoor control valve 18 . The eleventh pipe P<b>11 connects the other end of the third outdoor control valve 18 and one end of the sub-channel 152 of the supercooler 15 . The twelfth pipe P12 connects the other end of the sub-channel 152 of the supercooler 15 and the portion between both ends of the first pipe P1. These refrigerant pipes (P1-P12) may actually be configured by a single pipe, or may be configured by connecting a plurality of pipes via joints or the like.

The compressor 11 is a device that compresses a low-pressure refrigerant in the refrigeration cycle to a high pressure. In this embodiment, the compressor 11 has a closed structure in which a positive displacement compression element such as a rotary type or a scroll type is rotationally driven by a compressor motor (not shown). Further, here, the compressor motor can control the operating frequency by means of an inverter, so that the capacity of the compressor 11 can be controlled.

The accumulator 12 is a container for suppressing excessive intake of liquid refrigerant into the compressor 11 . The accumulator 12 has a predetermined volume according to the amount of refrigerant with which the refrigerant circuit RC is filled.

The four-way switching valve 13 is a channel switching valve for switching the flow of refrigerant in the refrigerant circuit RC. The four-way switching valve 13 can switch between a forward cycle state and a reverse cycle state. When the four-way switching valve 13 is in the normal cycle state, the first port (first pipe P1) and the second port (second pipe P2) are communicated, and the third port (fourth pipe P4) and the fourth port are connected. (the fifth pipe P5) (see the solid line of the four-way switching valve 13 in FIG. 1). When the four-way switching valve 13 is in a reverse cycle state, the first port (first pipe P1) and the third port (fourth pipe P4) are communicated, and the second port (second pipe P2) and the fourth port are connected. (the fifth pipe P5) (see the dashed line of the four-way switching valve 13 in FIG. 1).

The outdoor heat exchanger 14 is a heat exchanger that functions as a refrigerant condenser (or radiator) or evaporator (or heater). The outdoor heat exchanger 14 functions as a refrigerant condenser during normal cycle operation (operation in which the four-way switching valve 13 is in the normal cycle state). Further, the outdoor heat exchanger 14 functions as a refrigerant evaporator during reverse cycle operation (operation in which the four-way switching valve 13 is in the reverse cycle state). 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 to exchange heat between the refrigerant in the heat transfer tubes and the air (outdoor airflow described later) passing around the heat transfer tubes or the heat transfer fins.

The supercooler 15 is a heat exchanger that converts the inflowing refrigerant into a supercooled liquid refrigerant. The supercooler 15 is, for example, a double-tube heat exchanger, and the supercooler 15 includes a main channel 151 and sub-channels 152 . The supercooler 15 is configured such that the refrigerant flowing through the main channel 151 and the sub-channel 152 exchanges heat.

The first outdoor control valve 16 is an electrically operated valve whose degree of opening is controllable, and reduces the pressure or adjusts the flow rate of the inflowing refrigerant according to the degree of opening. The first outdoor control valve 16 is arranged between the outdoor heat exchanger 14 and the subcooler 15 (main flow path 151). In other words, it can be said that the first outdoor control valve 16 is arranged between the outdoor heat exchanger 14 and the liquid-side connecting pipe La.

The second outdoor control valve 17 is an electrically operated valve whose degree of opening can be controlled, and reduces the pressure or adjusts the flow rate of the inflowing refrigerant according to the degree of opening. The second outdoor control valve 17 is arranged between the supercooler 15 (main flow path 151 ) and the liquid-side shutoff valve 19 . By controlling the degree of opening of the second outdoor control valve 17, it is possible to change the refrigerant flowing from the outdoor unit 10 to the indoor unit 40 into a gas-liquid two-phase state.

The third outdoor control valve 18 is a motor-operated valve whose degree of opening can be controlled, and reduces the pressure or regulates the flow rate of the inflowing refrigerant according to the degree of opening. The outdoor third control valve 18 is arranged between the outdoor heat exchanger 14 and the supercooler 15 (sub-flow path 152).

The liquid-side closing valve 19 is a manual valve arranged at the connecting portion between the ninth pipe P9 and the liquid-side connecting pipe La. The liquid side shut-off valve 19 has one end connected to the ninth pipe P9 and the other end connected to the liquid side communication pipe La.

The gas side shutoff valve 20 is a manual valve arranged at the connecting portion between the first pipe P1 and the gas side connecting pipe Ga. The gas side shutoff valve 20 has one end connected to the first pipe P1 and the other end connected to the gas side communication pipe Ga.

The outdoor unit 10 also has an outdoor fan 25 that generates an outdoor airflow that passes through the outdoor heat exchanger 14 . The outdoor fan 25 is a blower that supplies the outdoor heat exchanger 14 with an outdoor airflow as a cooling source or a heating source for the refrigerant flowing through the outdoor heat exchanger 14 . The outdoor fan 25 includes an outdoor fan motor (not shown) as a drive source, and the start/stop and rotation speed of the outdoor fan 25 are appropriately controlled according to the situation.

The outdoor unit 10 is also provided with a plurality of outdoor sensors (not shown) for detecting the state of the refrigerant (mainly pressure or temperature) in the refrigerant circuit RC. Outdoor sensors are pressure sensors and temperature sensors such as thermistors or thermocouples. The outdoor sensor includes, for example, a suction pressure sensor that detects the refrigerant pressure (suction pressure) on the suction side of the compressor 11, and a discharge pressure sensor that detects the refrigerant pressure (discharge pressure) on the discharge side of the compressor 11. A refrigerant temperature sensor that detects the temperature of the refrigerant in the outdoor heat exchanger 14 (for example, the degree of supercooling SC), an outside air temperature sensor that detects the temperature of the outside air, and the like are included.

Further, the outdoor unit 10 has an outdoor unit control section that controls the operation/state of each device included in the outdoor unit 10 . The outdoor unit controller includes a microcomputer having a CPU, memory, and the like. The outdoor unit control section is electrically connected to each device (11, 13, 16, 17, 18, 25, etc.) and outdoor sensors included in the outdoor unit 10, and performs signal input/output with each other. Also, the outdoor unit control section individually transmits and receives control signals and the like to and from an indoor unit control section (described later) of each indoor unit 40 and a remote controller (not shown) via a communication line.

(1-2) Indoor unit 40
Each indoor unit 40 is connected to the outdoor unit 10 via a liquid side connecting pipe La and a gas side connecting pipe Ga. Each indoor unit 40 is arranged in parallel or in series with other indoor units 40 with respect to the outdoor unit 10 . In FIG. 1, the indoor unit 40a is arranged in series with the indoor unit 40b and the like, and is arranged in parallel with the indoor units 40c and 40d and the like. Each indoor unit 40 is arranged in the target space SP. In FIG. 2, the indoor units 40a and 40b are installed in the target space SP1 (more specifically, the ceiling space SPa of the target space SP1), and the indoor units 40c and 40d are located in the target space below the target space SP1. It is installed in SP2 (more specifically, the ceiling space SPa of the target space SP1). Therefore, in this embodiment, the installation height of the indoor units 40c and 40d is lower than the installation height of the indoor units 40a and 40b.

Each indoor unit 40 constitutes part of the refrigerant circuit RC (indoor circuit RC2). Each indoor unit 40 mainly includes a plurality of refrigerant pipes (a thirteenth pipe P13 and a fourteenth pipe P14), an indoor expansion valve 41, and an indoor heat exchanger 42 as devices that constitute the indoor circuit RC2. are doing.

The thirteenth pipe P<b>13 connects the liquid side communication pipe La and the liquid side refrigerant inlet/outlet of the indoor heat exchanger 42 . The fourteenth pipe P14 connects the gas side refrigerant inlet/outlet of the indoor heat exchanger 42 and the gas side connecting pipe Ga. These refrigerant pipes (P13, P14) may actually be configured by a single pipe, or may be configured by connecting a plurality of pipes via joints or the like.

The indoor expansion valve 41 is a motor-operated valve whose degree of opening can be controlled, and reduces the pressure or adjusts the flow rate of the inflowing refrigerant according to the degree of opening. The indoor expansion valve 41 is arranged on the thirteenth pipe P<b>13 and positioned between the liquid-side connecting pipe La and the indoor heat exchanger 42 . The indoor expansion valve 41 reduces the pressure of the refrigerant flowing into the indoor unit 40 from the liquid-side communication pipe La during normal cycle operation.

The indoor heat exchanger 42 is a heat exchanger that functions as a refrigerant evaporator (or heater) or condenser (or radiator). The indoor heat exchanger 42 functions as a refrigerant evaporator during normal cycle operation. In addition, the indoor heat exchanger 42 functions as a refrigerant condenser during reverse cycle operation. 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 the refrigerant in the heat transfer tubes and the air (indoor airflow described later) passing around the heat transfer tubes or the heat transfer fins.

The indoor unit 40 also has an indoor fan 45 for sucking air in the target space SP, passing the air through the indoor heat exchanger 42 to exchange heat with the refrigerant, and then sending the air back to the target space SP. The indoor fan 45 includes an indoor fan motor (not shown) as a drive source. The indoor fan 45 generates indoor airflow as a heating source or a cooling source for the refrigerant flowing through the indoor heat exchanger 42 when driven.

Further, the indoor unit 40 is provided with an indoor sensor (not shown) for detecting the state of the refrigerant (mainly pressure or temperature) in the refrigerant circuit RC. The indoor sensor is a pressure sensor or a temperature sensor such as a thermistor or thermocouple. The indoor-side sensors include, for example, a temperature sensor that detects the temperature of the refrigerant (for example, degree of superheat) in the indoor heat exchanger 42, a pressure sensor that detects the pressure of the refrigerant, and the like.

In addition, the indoor unit 40 has an indoor unit control section that controls the operation/state of each device included in the indoor unit 40 . The indoor unit control section has a microcomputer including a CPU, memory, and the like. The indoor unit control section is electrically connected to the devices (41, 45) and indoor sensors included in the indoor unit 40, and performs signal input/output with each other. Also, the indoor unit control section is connected to an outdoor unit control section and a remote controller (not shown) via a communication line, and transmits and receives control signals and the like.

(1-3) Liquid-side connecting pipe La, gas-side connecting pipe Ga
The liquid-side communication pipe La and the gas-side communication pipe Ga are refrigerant communication pipes that connect the outdoor unit 10 and each indoor unit 40, and are constructed on site. The pipe lengths and pipe diameters of the liquid-side connecting pipe La and the gas-side connecting pipe Ga are appropriately selected according to the design specifications and the installation environment.

The liquid-side communication pipe La is a pipe that forms a liquid-side communication circuit RC3 (liquid-side communication circuit RC3a) between the outdoor unit 10 and each indoor unit 40 . The liquid-side communication pipe La is configured by connecting a plurality of pipes, joints, and the like. Specifically, the liquid-side connecting pipe La includes a plurality of connecting pipes (first liquid-side connecting pipe L1, second liquid-side connecting pipe L2, third liquid-side connecting pipe L3, fourth liquid-side connecting pipe L4, fifth ), a plurality of branch portions BP (hereinafter referred to as "liquid side branch portions BPa"), and the like. Each connecting pipe (L1, L2, L3, L4, L5, . A plurality of pipes may be connected to each other.

One end of the first liquid-side communication pipe L1 is connected to the liquid-side shutoff valve 19 of the outdoor unit 10, and the liquid-side communication circuit RC3a is connected to the outside of the other communication pipes (L2, L3, L4, L5, . . . ). It is arranged on the unit 10 side. The first liquid-side connecting pipe L1, the second liquid-side connecting pipe L2, and the third liquid-side connecting pipe L3 are connected at a liquid-side branch portion BPa located closest to the outdoor unit 10 in the liquid-side connecting circuit RC3a. are in communication.

Each of the other communication pipes (L2, L3, L4, L5, . to form In this embodiment, the second liquid side connecting pipe L2 corresponds to the indoor units 40a and 40b, etc., and the third liquid side connecting pipe L3 and the fourth liquid side connecting pipe L4 correspond to the indoor units 40c, 40d, etc. The fifth liquid-side communication pipe L5 corresponds to other indoor units 40 and the like.

One end of each of the second liquid side connecting pipe L2 and the third liquid side connecting pipe L3 communicates with the other end of the first liquid side connecting pipe L1 via a branch portion BP. The second liquid side connecting pipe L2 and the third liquid side connecting pipe L3 are arranged in parallel with each other with respect to the first liquid side connecting pipe L1.

One end side of the fourth liquid-side communication pipe L4 and the fifth liquid-side communication pipe L5 communicates with the other end side of the third liquid-side communication pipe L3 via the branch portion BP. The fourth liquid side connecting pipe L4 and the fifth liquid side connecting pipe L5 are arranged in parallel with each other with respect to the third liquid side connecting pipe L3.

The gas side communication pipe Ga constitutes a gas side communication circuit RC3 (gas side communication circuit RC3b) between the outdoor unit 10 and each indoor unit 40, and is a pipe through which a low-pressure refrigerant flows during operation. The gas-side communication pipe Ga is configured by connecting a plurality of pipes, joints, and the like. The gas-side connecting pipe Ga includes a plurality of connecting pipes (first gas-side connecting pipe G1, second gas-side connecting pipe G2, third gas-side connecting pipe G3, fourth gas-side connecting pipe G4, fifth gas-side connecting pipe G5), a plurality of branch portions BP (hereinafter referred to as “gas side branch portions BPb”), and the like. Each connecting pipe (G1, G2, G3, G4, G5, . A plurality of pipes may be connected to each other.

One end of the first gas side communication pipe G1 is connected to the gas side shutoff valve 20 of the outdoor unit 10, and in the gas side communication circuit RC3b, more than the other communication pipes (G2, G3, G4, G5, . . . ), It is arranged on the outdoor unit 10 side. The first gas-side communication pipe G1, the second gas-side communication pipe G2, and the third gas-side communication pipe G3 are connected at a gas-side branch portion BPb located closest to the outdoor unit 10 in the gas-side communication circuit RC3b, are in communication.

Each of the other communication pipes (G2, G3, G4, G5, . to form In this embodiment, the second gas side communication pipe G2 corresponds to the indoor units 40a and 40b and the like, and the third gas side communication pipe G3 and the fourth gas side communication pipe G4 correspond to the indoor units 40c and 40d and the like. The fifth gas side communication pipe G5 corresponds to other indoor units 40 and the like.

One end side of the second gas side communication pipe G2 and the third gas side communication pipe G3 communicates with the other end side of the first gas side communication pipe G1 via the branch portion BP. The second gas side communication pipe G2 and the third gas side communication pipe G3 are arranged in parallel with each other with respect to the first gas side communication pipe G1.

One end side of the fourth gas side communication pipe G4 and the fifth gas side communication pipe G5 communicates with the other end side of the third gas side communication pipe G3 via the branch portion BP. The fourth gas side connecting pipe G4 and the fifth gas side connecting pipe G5 are arranged in parallel with each other with respect to the third gas side connecting pipe G3.

In this embodiment, as shown in FIG. 2, the second liquid-side communication pipe L2 and the second gas-side communication pipe G2 are arranged so as to extend mainly along the horizontal direction in the ceiling space SPa of the target space SP1. It is Further, as shown in FIG. 2, the fourth liquid-side communication pipe L4 and the fourth gas-side communication pipe G4 are mainly arranged in the left-right direction (horizontal direction) in the ceiling space SPa of the target space SP2 on the lower floor than the target space SP1. direction). That is, in the present embodiment, the installation height of the fourth liquid side connection pipe L4 and the fourth gas side connection pipe G4 is lower than the installation height of the second liquid side connection pipe L2 and the second gas side connection pipe G2. Further, as shown in FIG. 2, the third liquid-side communication pipe L3 and the third gas-side communication pipe G3 are mainly arranged in the space between the outer wall of the building B1 and the inner wall of the target space SP, and are mainly arranged in the vertical direction. (vertical direction).

In the following description, one or both of the liquid-side connecting pipe La and the gas-side connecting pipe Ga will be referred to as "refrigerant connecting pipe". Further, in the communication circuit RC3, among the communication pipes connected at the branch portion BP, the communication pipes located on the outdoor unit 10 side (for example, L1 for L2 and L3, and L3 for L4 and L5) are referred to as "outdoor unit side Any/all of the connecting pipes communicating with the outdoor unit side connecting pipe CP1 (for example, L2 and L3 for L1, and L4 and L5 for L3) are referred to as “indoor unit side connecting pipe CP2”. called.

The branching portion BP (liquid side branching portion BPa, gas side branching portion BPb) included in the refrigerant communication pipe branches the refrigerant flowing from the outdoor unit 10 side (that is, the outdoor unit side communication pipe CP1 side) to the indoor unit side communication pipe CP2. Also, it is a portion that joins the refrigerant flowing from the indoor unit side communication pipe CP2 side.

In the air conditioning system 100, the branch portion BP is configured by a branch pipe unit 50 (first branch pipe unit 51 or second branch pipe unit 60). Details of the branch pipe unit 50 will be described later.

(2) Flow of Refrigerant in Refrigerant Circuit RC Hereinafter, the flow of refrigerant in the refrigerant circuit RC will be described. The air conditioning system 100 mainly performs forward cycle operation such as cooling operation and reverse cycle operation such as heating operation. The low pressure in the refrigerating cycle here is the pressure of the refrigerant sucked into the compressor 11 , and the high pressure in the refrigerating cycle is the pressure of the refrigerant discharged from the compressor 11 .

(2-1) Flow of Refrigerant During Normal Cycle Operation FIG. 3 is a schematic diagram showing an example of a refrigeration cycle during normal cycle operation (during normal control). During normal cycle operation, the four-way switching valve 13 is controlled to the normal cycle state, and the refrigerant charged in the refrigerant circuit RC is mainly supplied to the outdoor circuit RC1 (compressor 11, outdoor heat exchanger 14, outdoor first control valve 16, main flow path 151 of supercooler 15, outdoor second control valve 17),
The liquid side communication circuit RC3a, the indoor circuit RC2 (indoor expansion valve 41 and indoor heat exchanger 42) of the operating indoor unit 40 (operating indoor unit), and the compressor 11 are circulated in this order. In the forward cycle operation, part of the refrigerant flowing through the sixth pipe P6 branches to the ninth pipe P9, passes through the outdoor third control valve 18 and the supercooler 15 (sub-flow path 152), and then flows into the gas side. It is returned to the outdoor circuit RC1 (compressor 11) via the communication circuit RC3b.

Specifically, when the positive cycle operation is started, in the outdoor circuit RC1, the refrigerant is sucked into the compressor 11, compressed to the high pressure of the refrigeration cycle, and then discharged (Fig. 3a-b reference). In the compressor 11, capacity control is performed according to the heat load required in the indoor unit. Specifically, the target value of the suction pressure (see FIG. 3a) is set according to the heat load required by the indoor unit 40, and the operating frequency of the compressor 11 is adjusted so that the suction pressure becomes the target value. controlled. The gas refrigerant discharged from the compressor 11 flows into the gas side inlet/outlet of the outdoor heat exchanger 14 .

The gaseous refrigerant that has flowed into the outdoor heat exchanger 14 exchanges heat with the outdoor air flow sent by the outdoor fan 25 in the outdoor heat exchanger 14 to radiate heat and condense (see bd in FIG. 3). At this time, the refrigerant becomes a supercooled liquid refrigerant with a degree of supercooling SC (see cd in FIG. 3). The refrigerant that has flowed out from the liquid side inlet/outlet of the outdoor heat exchanger 14 branches while flowing through the sixth pipe P6.

One of the refrigerants branched in the course of flowing through the sixth pipe P6 flows into the main flow path 151 of the supercooler 15 via the first outdoor control valve 16 . The refrigerant that has flowed into the main channel 151 of the supercooler 15 exchanges heat with the refrigerant flowing through the sub-channel 152 to be cooled and further supercooled (see de in FIG. 3).

The liquid refrigerant flowing out of the main flow path 151 of the subcooler 15 is depressurized or flow-adjusted according to the degree of opening of the second outdoor control valve 17, becomes a gas-liquid two-phase state, and has a higher pressure than the high-pressure refrigerant. This results in an intermediate pressure refrigerant with a higher pressure than the low, low pressure refrigerant (see ef in FIG. 3). As a result, during normal cycle operation, a gas-liquid two-phase refrigerant is sent to the liquid-side communication circuit RC3a (liquid-side communication pipe La), and the refrigerant sent from the outdoor unit 10 side to the indoor unit 40 side is a gas-liquid two-phase refrigerant. Conveyance is realized. That is, the second outdoor control valve 17 reduces the pressure of the refrigerant so that the refrigerant flowing from the outdoor unit 10 to the indoor unit 40 passes through the liquid side connecting pipe La in a gas-liquid two-phase state during normal cycle operation. In relation to this, compared to the case of liquid transportation in which the refrigerant flowing through the liquid side connecting pipe La is in a liquid state, the liquid side connecting pipe La is not filled with the liquid state refrigerant, and the liquid side connecting pipe The amount of refrigerant present in La can be reduced.

The gas-liquid two-phase refrigerant that has flowed out of the outdoor unit 10 flows into the indoor circuit RC2 of the operating indoor unit via the liquid side communication circuit RC3a. The pressure of the refrigerant flowing through the liquid-side communication circuit RC3a decreases due to pressure loss (see fg in FIG. 3).

The other refrigerant branched in the process of flowing through the sixth pipe P6 in the outdoor circuit RC1 flows into the outdoor third control valve 18, and after being depressurized or flow rate adjusted according to the degree of opening of the outdoor third control valve 18, It flows into the sub-channel 152 of the supercooler 15 . The refrigerant that has flowed into the sub-channel 152 of the supercooler 15 exchanges heat with the refrigerant flowing through the main channel 151, and then passes through the twelfth pipe P12 and joins the refrigerant flowing through the first pipe P1.

The refrigerant that has flowed into the indoor circuit RC2 flows into the indoor expansion valve 41 and is decompressed according to the degree of opening of the indoor expansion valve 41 to a low pressure in the refrigeration cycle (see gh in FIG. 3). It flows into heat exchanger 42 .

The refrigerant that has flowed into the indoor heat exchanger 42 exchanges heat with the indoor air flow sent by the indoor fan 45 and evaporates to become a gas refrigerant (see ha in FIG. 3). The gas refrigerant that has flowed out of the indoor heat exchanger 42 flows out of the indoor circuit RC2.

The refrigerant flowing out of the indoor circuit RC2 flows through the gas side communication circuit RC3b and flows into the outdoor circuit RC1. The refrigerant that has flowed into the outdoor circuit RC1 flows through the first pipe P1, passes through the four-way switching valve 13 and the second pipe P2, and flows into the accumulator 12. The refrigerant that has flowed into the accumulator 12 is sucked into the compressor 11 again after being temporarily stored.

(2-2) Flow of Refrigerant During Reverse Cycle Operation During reverse cycle operation, the four-way switching valve 13 is controlled to the reverse cycle state, and the refrigerant charged in the refrigerant circuit RC is mainly supplied to the outdoor circuit RC1 (compressor 11), gas side communication circuit RC3b, indoor circuit RC2 of the operating indoor unit (indoor heat exchanger 42 and indoor expansion valve 41), liquid side communication circuit RC3a, outdoor circuit RC1 (outdoor second control valve 17, supercooling 15, the first outdoor control valve 16, the outdoor heat exchanger 14, and the compressor 11).

Specifically, when the reverse cycle operation is started, the refrigerant is sucked into the compressor 11 in the outdoor circuit RC1, compressed to a high pressure, and then discharged. In the compressor 11, capacity control is performed according to the heat load required in the indoor unit. The gas refrigerant discharged from the compressor 11 flows out of the outdoor unit 10 through the fourth pipe P4 and the first pipe P1, and flows into the indoor circuit RC2 of the operating indoor unit through the gas side communication circuit RC3b.

The refrigerant that has flowed into the indoor circuit RC2 flows into the indoor heat exchanger 42, exchanges heat with the indoor air flow sent by the indoor fan 45, and is condensed. The refrigerant that has flowed out of the indoor heat exchanger 42 flows into the indoor expansion valve 41 and is decompressed according to the degree of opening of the indoor expansion valve 41 to a low pressure in the refrigeration cycle. After that, the refrigerant flows out from the indoor circuit RC2.

The refrigerant that has flowed out of the indoor circuit RC2 flows into the outdoor circuit RC1 through the liquid side communication circuit RC3a. The refrigerant that has flowed into the outdoor circuit RC1 passes through the ninth pipe P9, the second outdoor control valve 17, the eighth pipe P8, the subcooler 15 (main flow path 151), the seventh pipe P7, the first outdoor control valve 16 and It flows into the liquid side inlet/outlet of the outdoor heat exchanger 14 via the sixth pipe P6.

The refrigerant that has flowed into the outdoor heat exchanger 14 exchanges heat with the outdoor air flow sent by the outdoor fan 25 in the outdoor heat exchanger 14 and evaporates. After that, the refrigerant flows out from the gas side inlet/outlet of the outdoor heat exchanger 14 and flows into the accumulator 12 via the fifth pipe P5, the four-way switching valve 13 and the second pipe P2. The refrigerant that has flowed into the accumulator 12 is sucked into the compressor 11 again after being temporarily stored.

(3) Details of branch pipe unit 50 The branch pipe unit 50 is a unit for configuring the branch portion BP in the communication circuit RC3. The branch pipe unit 50 is pre-assembled at a factory, site, or the like before construction, and is connected to other pipes (here, the outdoor unit side connecting pipe CP1 and the indoor unit side connecting pipe CP2) at the construction site.

Each branch pipe unit 50 arranged in the refrigerant circuit RC is either a first branch pipe unit 51 or a second branch pipe unit 60 having a function of forming a trap in the communication circuit RC3. At each branch portion BP, the optimum one of the first branch pipe unit 51 and the second branch pipe unit 60 is selected.

(3-1) First branch pipe unit 51
FIG. 4 is a schematic configuration diagram of the first branch pipe unit 51. As shown in FIG. In addition, in this embodiment, the x direction and the y direction are orthogonal to each other. The first branch pipe unit 51 includes a main pipe 52 , a branch pipe group 55 including a plurality of (here, two) branch pipes 54 , and a connecting pipe portion 58 . In the first branch pipe unit 51 , the main pipe 52 and the respective branch pipes 54 are connected and communicated with each other via the connecting pipe portion 58 .

The main pipe 52 extends mainly along the x direction (see FIGS. 4, 6, etc.). The main pipe 52 is positioned closer to the outdoor unit 10 than the connecting pipe portion 58 in the installed state. The main pipe 52 is in one-to-one correspondence with any one of the outdoor unit side communication pipes CP1, and one end 521 is connected to the corresponding outdoor unit side communication pipe CP1 in the installed state. The other end 522 of the main pipe 52 is connected to the first connecting portion 581 of the connecting pipe portion 58 . The main pipe 52 forms a flow path for the refrigerant flowing to each connected branch pipe 54 or for the refrigerant flowing from each branch pipe 54 .

Each branch pipe 54 extends mainly along the x-direction (see FIGS. 4, 6, etc.). Each branch pipe 54 is positioned closer to the corresponding indoor unit 40 than the connecting pipe portion 58 in the installed state. One end 541 of each branch pipe 54 is individually connected to the second connection portion 582 of the connection pipe portion 58 in the installed state. Each branch pipe 54 is in one-to-one correspondence with one of the indoor unit side communication pipes CP2, and the other end 542 is connected to the corresponding indoor unit side communication pipe CP2.

The connection pipe portion 58 connects the main pipe 52 in the first branch pipe unit 51 and the branch pipe group 55 (each branch pipe 54). In this embodiment, as shown in FIG. 4, the connecting pipe portion 58 is curved in a substantially U-shape or a substantially C-shape when viewed in the y direction. The connecting pipe portion 58 has a first connecting portion 581 connected to the main pipe 52 . The connection pipe portion 58 has a plurality of second connection portions 582 (the same number as the number of branch pipes 54 included in the first branch pipe unit 51, two here) connected to the corresponding branch pipes 54 . The connecting pipe portion 58 has a first connecting portion 581 on one end side, and branches into two on the other end side, and has a second connecting portion 582 at each branched end.

(3-2) Second branch pipe unit 60
FIG. 5 is a schematic configuration diagram of the second branch pipe unit 60. As shown in FIG. In addition, in this embodiment, the x direction and the y direction are orthogonal to each other.

The second branch pipe unit 60 includes a main pipe 70 , a branch pipe group 88 including a plurality of (here, two) branch pipes 80 , and a connection pipe section 90 . In the second branch pipe unit 60 , the main pipe 70 and the branch pipes 80 are connected and communicated via the connection pipe portion 90 .

The main pipe 70 (corresponding to the "main pipe" described in the claims) is a pipe for sending the refrigerant flowing from the outdoor unit side connecting pipe CP1 to the connecting pipe portion 90, or sending the refrigerant flowing from the connecting pipe portion 90 to the outdoor unit side connecting pipe CP1. It is a pipe to send to. The main pipe 70 is positioned closer to the outdoor unit 10 than the connection pipe portion 90 in the installed state. The main pipe 70 is in one-to-one correspondence with any of the outdoor unit side communication pipes CP1. The main pipe 70 has a first main pipe portion 71 that extends mainly along the x-direction (see FIGS. 5, 7, etc.). In this embodiment, the distal end of the first main pipe portion 71 constitutes one end 701 of the main pipe 70 , and the distal end of the first main pipe portion 71 constitutes the other end 702 of the main pipe 70 . The main pipe 70 is connected to the corresponding outdoor unit side communication pipe CP1 at the end (701) in the installed state. The main pipe 70 has a tip ( 702 ) connected to the first connecting portion 901 of the connecting pipe portion 90 . The main pipe 70 forms a channel for the refrigerant flowing to each connected branch pipe 80 or for the refrigerant flowing from each branch pipe 80 . In addition, in the present embodiment, the configuration of the main pipe 70 is substantially the same as that of the main pipe 52 of the first branch pipe unit 51 .

In this embodiment, the branch pipe group 88 includes two branch pipes 80 (80a and 80b). Each branch pipe 80 (corresponding to a “branch pipe” described in the claims) is positioned closer to the corresponding indoor unit 40 than the connecting pipe portion 90 in the installed state. One end 801 of each branch pipe 80 is individually connected to the second connection portion 902 of the connection pipe portion 90 in the installed state. Each branch pipe 80 is in one-to-one correspondence with one of the indoor unit side communication pipes CP2, and the other end 802 is connected to the corresponding indoor unit side communication pipe CP2.

The dimensions of each branch pipe 80 are appropriately selected according to the installation environment and design specifications. In this embodiment, the dimension of each branch pipe 80 is a dimension suitable for configuring the liquid-side communication circuit RC3a (specifically, it is set at 2 minutes or more and 6 minutes or less). Here, "2 minutes" and "6 minutes" are the nominal diameters of pipe sizes that are commonly used. Specifically, "two minutes" here is 1/4 inch with an outer diameter of 6.35 mm (or approximate) and an inner diameter of 4.75 mm (or approximate). Also, "six minutes" here is 3/4 inch with an outer diameter of 19.05 mm (or an approximate value) and an inner diameter of 16.95 mm (or an approximate value).

Each branch pipe 80 has a portion extending along the x direction (corresponding to the “first direction” described in the claims) and a portion extending in the y direction (corresponding to the “second direction” described in the claims) intersecting the x direction. ). Specifically, the branch pipe 80 includes a first extending portion 81 , a second extending portion 82 , a folded portion 83 , a third extending portion 84 and a fourth extending portion 85 . In the present embodiment, each portion (81-85) of the branch pipe 80 extends continuously in the order of the first extending portion 81, the second extending portion 82, the folded portion 83, the third extending portion 84 and the fourth extending portion 85. and are integrated.

The first extending portion 81 (corresponding to the “fifth portion” described in the claims) is a portion that extends mainly along the x-direction (that is, the extending direction of the main pipe 70). The first extending portion 81 is positioned closer to the main pipe 70 than the other portions of the branch pipe 80 (the second extending portion 82 to the fourth extending portion 85). In other words, in the installed state, the first extension portion 81 is more likely to extend than the other portions (the second extension portion 82, the folded portion 83, the third extension portion 84, and the fourth extension portion 85) of the branch pipe 80 in the connection circuit RC3 to the outdoor unit. Located on the 10th side. In this embodiment, one end of the first extending portion 81 corresponds to one end 801 of the branch pipe 80 and is connected to the second connecting portion 902 of the connecting pipe portion 90 in the installed state. The other end of the first extending portion 81 is connected to the second extending portion 82 . In the installed state, the first extending portion 81 sends the inflowing coolant from one of the connecting pipe portion 90 and the second extending portion 82 to the other.

The second extending portion 82 (corresponding to the “second portion” described in the claims) extends mainly along the y direction (that is, the direction intersecting the extending direction of the main pipe 70). In this embodiment, the second extending portion 82 extends perpendicularly to the extending direction of the first extending portion 81 and the main pipe 70 . The second extending portion 82 extends between the first extending portion 81 and the folded portion 83 . It is positioned closer to the main pipe 70 than the folded portion 83 , the third extending portion 84 and the fourth extending portion 85 . That is, in the installed state, the second extending portion 82 is located closer to the indoor unit 40 than the first extending portion 81 in the connecting circuit RC3, and is closer to the indoor unit 40 than the folded portion 83, the third extending portion 84, and the fourth extending portion 85. Located on the outdoor unit 10 side. One end of the second extension portion 82 is connected to the first extension portion 81 . The other end of the second extending portion 82 is connected to the folded portion 83 . In the installed state, the second extending portion 82 sends the inflowing coolant from one of the first extending portion 81 and the folded portion 83 to the other.

The folded portion 83 (corresponding to the “folded portion” described in the claims) extends mainly along the y direction (the direction in which the second extending portion 82 extends), then curves to extend along the x direction, and further curves. It is a portion extending along the y direction (the direction in which the third extending portion 84 extends). The folded portion 83 is a portion that extends between the second extending portion 82 and the folded portion 83 to connect them. The folded portion 83 is located closer to the main pipe 70 than the third extending portion 84 and the fourth extending portion 85 are. That is, in the installed state, the folded portion 83 is positioned between the second extending portion 82 and the third extending portion 84 in the connecting circuit RC3, and is closer to the indoor unit 40 than the first extending portion 81 and the second extending portion 82 are. , and is positioned closer to the outdoor unit 10 than the third extending portion 84 and the fourth extending portion 85 . One end of the folded portion 83 is connected to the other end of the second extending portion 82 . The other end of the folded portion 83 is connected to the third extending portion 84 . In the installed state, the folded portion 83 constitutes a coolant channel that folds the inflowing coolant from one of the second extending portion 82 and the third extending portion 84 to the other. Although the folded portion 83 is shown to have a portion extending linearly in the x direction in the drawing, it may be configured by a tube bent in a U shape. The use of such a U-shaped tube can reduce the influence of the pressure loss of the refrigerant.

The third extending portion 84 (corresponding to the “third portion” described in the claims) is a portion that extends mainly along the y direction (that is, the direction intersecting the extending direction of the main pipe 70). The extending direction of the third extending portion 84 is opposite to the extending direction of the second extending portion 82 . The third extending portion 84 is a portion extending between the folded portion 83 and the fourth extending portion 85 to connect them. The third extending portion 84 is located closer to the main pipe 70 than the fourth extending portion 85 is. That is, in the installed state, the third extending portion 84 is located closer to the indoor unit 40 than the first extending portion 81, the second extending portion 82, and the folded portion 83 in the connecting circuit RC3, and is located closer to the indoor unit 40 than the fourth extending portion 85. Located on the outdoor unit 10 side. One end of the third extending portion 84 is connected to the other end of the folded portion 83 . The other end of the third extending portion 84 is connected to the fourth extending portion 85 . In the installed state, the third extending portion 84 sends the inflowing coolant from one of the folded portion 83 and the fourth extending portion 85 to the other.

The fourth extension portion 85 (corresponding to the “fourth portion” described in the claims) is a portion that extends mainly along the x-direction (that is, the extension direction of the main pipe 70). The fourth extending portion 85 extends perpendicularly to the extending direction of the third extending portion 84 . The extending direction of the fourth extending portion 85 is the same as the extending direction of the first extending portion 81 . The fourth extending portion 85 is a portion that extends between the third extending portion 84 and the indoor unit side communication pipe CP2 to connect them in the installed state. The fourth extending portion 85 is located closer to the indoor unit 40 than the first extending portion 81, the second extending portion 82, the folded portion 83 and the third extending portion 84 in the connecting circuit RC3 in the installed state. One end of the fourth extending portion 85 is connected to the other end of the third extending portion 84 . The other end of the fourth extending portion 85 corresponds to the other end 802 of the branch pipe 80, and is connected to the corresponding indoor unit side communication pipe CP2 in the installed state. In the installed state, the fourth extending portion 85 sends the inflowing refrigerant from one of the third extending portion 84 and the indoor unit side connecting pipe CP2 to the other.

The connecting pipe portion 90 connects the main pipe 70 in the second branch pipe unit 60 and the branch pipe group 88 (each branch pipe 80). In this embodiment, as shown in FIG. 5, the connecting pipe portion 90 is curved in a substantially U-shape or a substantially C-shape when viewed from the y direction. The connecting pipe portion 90 has a first connecting portion 901 connected to the main pipe 70 . The connection pipe portion 90 has a plurality of second connection portions 902 (the same number as the number of branch pipes 80 included in the second branch pipe unit 60, two here) connected to the corresponding branch pipes 80 . The connection tube part 90 has a first connection part 901 on one end side, and branches into two on the other end side, and has a second connection part 902 at each branched end. In addition, in the present embodiment, the configuration of the connection pipe portion 90 is substantially the same as that of the connection pipe portion 90 of the first branch pipe unit 51 .

(3-3) Installation Mode of Branch Pipe Unit 50 FIG. 6 is a schematic diagram showing an example of the installation mode of the first branch pipe unit 51. As shown in FIG. FIG. 7 is a schematic diagram showing an example of an installation mode of the second branch pipe unit 60. As shown in FIG. 6 and 7 show an example in which the branch pipe unit 50 is installed in the ceiling space SPa (the ceiling space of the target space SP). 6 and 7, the directions of up, down, left, and right are shown, the left-right direction corresponds to the x direction in FIG. 4 or FIG. 5, and the up-down direction corresponds to the y direction in FIG. corresponds to the direction. Here, the left-right direction is included in the horizontal direction, and the up-down direction is included in the vertical direction. That is, in this embodiment, when the branch pipe unit 50 is installed, the x direction corresponds to the horizontal direction, and the y direction corresponds to the vertical direction. 6 and 7, the front-rear direction perpendicular to the left-right direction corresponds to the z direction in FIG. 4 or 5 and is included in the horizontal direction.

The branch pipe unit 50 is installed together with the outdoor unit side connecting pipe CP1 and the indoor unit side connecting pipe CP2 in the ceiling space SPa. The ceiling space SPa is a narrow space formed between the upper surface of the ceiling of the target space SP (ceiling bottom surface C1) and the roof or the floor of the upper floor (ceiling top surface C2). The ceiling space SPa is a space with a large horizontal dimension and a small vertical dimension.

In this embodiment, as shown in FIGS. 6 and 7, the first branch pipe unit 51 and the second branch pipe unit 60 have branch pipes (54, 80) intersecting the horizontal direction (here, the extension direction x). z direction), and the extension direction of each branch pipe (54, 80) and the extension direction of the main pipe (52, 70) are the same (here, both directions are different, but both extension directions are horizontal). ). In relation to this, in the ceiling space SPa, the main extension direction of the indoor unit side communication pipe CP2 (here, the left and right direction, i.e., the horizontal direction) and the main extension direction of the outdoor unit side communication pipe CP1 (here, the left and right direction, i.e., horizontal direction) are substantially the same. That is, in the ceiling space SPa having a narrow vertical length, the first branch pipe unit 51 and the second branch pipe unit 60 are arranged in the main extension direction of the indoor unit side communication pipe CP2 (here, the left and right direction, that is, the horizontal direction). ) and the main extending direction of the outdoor unit-side connecting pipe CP1 (here, the lateral direction, that is, the horizontal direction) are substantially the same.

The outdoor unit side connecting pipe CP1 extends along the main extending direction (the right direction in FIGS. 6 and 7) of the indoor unit side connecting pipe CP2, and is connected to the first branch pipe unit 51 or the second branch pipe unit 60. part (one end 521 or 701 of the main pipe). The outdoor unit side connecting pipe CP1, the indoor unit side connecting pipe CP2, the first branch pipe unit 51 and/or the second branch pipe unit 60 are fitted with fixtures (not shown) fixed to the top surface C2 behind the ceiling. Therefore, it is suspended from the ceiling in the ceiling space SPa. The outdoor unit side connecting pipe CP1, the indoor unit side connecting pipe CP2, the first branch pipe unit 51 and the second branch pipe unit 60 are covered with a heat insulating material 95 for preventing dew condensation.

In FIG. 6, the first branch pipe unit 51 is installed in the ceiling space SPa in such a posture that the main pipe 52 and branch pipes 54 extend in the left-right direction (that is, in the horizontal direction).

In FIG. 7, the second branch pipe unit 60 has the main pipe 70 and the first extension portion 81, the folded portion 83 and the fourth extension portion 85 of the branch pipe 80 extending in the left-right direction (that is, in the horizontal direction). is installed in the ceiling space SPa in such a posture that the second extending portion 82 and the third extending portion 84 of the above extend along the vertical direction (that is, the vertical direction). Here, in the second branch pipe unit 60 , the second extending portion 82 of the branch pipe 80 extends along a direction (here, the y direction) intersecting (here, perpendicular to) the extending direction of the main pipe 70 . The second extending portion 82 is arranged in such a posture as to extend along the upward direction, as shown in FIG. 7 . That is, the second extending portion 82 constitutes a “rising portion V1” (upward extending portion) extending upward in the installed state.

The rising portion V1 (the second extending portion 82) functions as a trap portion T1 together with any or all of the other portions (81, 83-85) included in the branch pipe 80. During normal cycle operation, the trap section T1 is connected when the indoor unit 40 in the operating state (operation indoor unit) and the indoor unit 40 in the operation stop state (hereinafter referred to as "stop indoor unit") coexist. It is a portion that suppresses the refrigerant flowing from the pipe portion 90 from flowing toward the stopped indoor unit.

(4) Function of second branch pipe unit 60 The second branch pipe unit 60 also functions as a "trap component" that configures the trap part T1. Refrigerant flows through the second branch pipe unit 60 in the manner shown in FIG. 8 during normal cycle operation. FIG. 8 is a schematic diagram showing an example of refrigerant flow in the second branch pipe unit 60 during normal cycle operation. The two-dot chain line arrows in FIG. 8 indicate the direction in which the refrigerant flows during normal cycle operation. 8, only one branch pipe 80 of the branch pipe group 88 is drawn.

In the second branch pipe unit 60 , the gas-liquid two-phase refrigerant flowing from the outdoor unit side connecting pipe CP<b>1 flows into the main pipe 70 during normal cycle operation. The refrigerant that has flowed into one end 701 of the main pipe 70 flows horizontally toward the other end 702 side (indoor unit 40 side) and flows into the connecting pipe portion 90 . The refrigerant that has flowed into the first connection portion 901 of the connection pipe portion 90 branches and flows toward the second connection portions 902 and into the branch pipes 80 . After flowing into the branch pipe 80 communicating with the indoor unit, the refrigerant flows from the one end 801 side to the other end 802 side, and then flows into the indoor unit side communication pipe CP2. More specifically, the coolant that has flowed horizontally in the first extending portion 81 flows into the second extending portion 82 , flows upward, and flows into the folded portion 83 . The coolant that has flowed into the folded portion 83 changes its flow direction and flows horizontally, then changes its flow direction again, flows downward, and flows into the third extending portion 84 . The coolant that has flowed into the third extending portion 84 flows downward and then flows into the fourth extending portion 85 . The refrigerant that has flowed into the fourth extending portion 85 flows in the horizontal direction, and flows into the indoor unit side communication pipe CP2.

When the operating indoor unit and the stopped indoor unit coexist during normal cycle operation, the refrigerant flows in the manner shown in FIG. 9 in the second branch pipe unit 60 . FIG. 9 is a schematic diagram showing an example of the flow of refrigerant when the operating indoor unit and the stopped indoor unit coexist during normal cycle operation. In FIG. 9, the reference symbol "R" represents the gas-liquid two-phase refrigerant, and the reference symbol "G" represents the gas refrigerant (gas pool) filled in the trap portion T1. Also, the two-dot chain line arrow in FIG. 9 represents the direction in which the refrigerant flows during normal cycle operation.

During normal cycle operation, when the operating indoor unit and the stopped indoor unit are mixed, the gas-liquid two-phase refrigerant flowing from the outdoor unit side connecting pipe CP1 flows into the main pipe 70 . The refrigerant that has flowed into the main pipe 70 flows toward the indoor unit 40 side and flows into the connecting pipe portion 90 . The refrigerant that has flowed into the connecting pipe portion 90 branches and flows into each branch pipe 80 . The refrigerant that has flowed into the branch pipe 80 (rear branch pipe 80 in FIG. 9) 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 communication pipe CP2. On the other hand, in the branch pipe 80 (the front side branch pipe 80 in FIG. 9) communicating with the stop indoor unit, the trap portion T1 (here, mainly the rising portion V1) acts as a resistance, and the flow of the refrigerant flowing into the one end 801 of the branch pipe 80 is attenuated. do. In relation to this, a situation (gas pool G) occurs in which the trap portion T1 is filled with the gas refrigerant of the gas-liquid two-phase refrigerant. That is, the trap portion T1 is filled with gaseous refrigerant. As a result, the gas-liquid two-phase refrigerant that has flowed into one end 801 of the branch pipe 80 is suppressed from flowing toward the other end 802 . As a result, the refrigerant is suppressed from flowing to the side of the stopped indoor unit, and the shortage of the amount of refrigerant circulated in the operating indoor unit is suppressed. In other words, performance deterioration in the cab unit is suppressed.

(5) About the installation location of the second branch pipe unit 60 The second branch pipe unit 60 is filled with refrigerant in a gaseous state when the operating indoor unit and the stopped indoor unit are mixed during normal cycle operation, and the branch pipe It functions as a "trap forming part" that forms a trap part T1 that suppresses the gas-liquid two-phase refrigerant that has flowed into one end 801 of 80 from flowing to the other end 802 side. In the refrigerant circuit RC, the position of the branch portion BP formed by the second branch pipe unit 60 is appropriately selected according to design specifications and installation environment. That is, in the refrigerant circuit RC, the second branch pipe unit 60 is operated during the normal cycle operation, depending on the installation state of each indoor unit 40 included in the air conditioning system 100, the installation height of the communication pipe, the branch state, etc. When the indoor unit and the stopped indoor unit coexist, it is arranged at an effective position for suppressing the refrigerant from flowing to the stopped indoor unit side and suppressing the shortage of the refrigerant circulation amount in the operating indoor unit.

In the present embodiment, the second branch pipe unit 60 is connected to the liquid side branch portion BPa (liquid side branch portion BL1 shown in FIG. 2) located closest to the outdoor unit 10 (that is, most upstream during normal cycle operation). are placed. Specifically, in the liquid side branch portion BL1, the main pipe 70 is connected to the first liquid side communication pipe L1, the first branch pipe 80a is connected to the second liquid side communication pipe L2, and the second branch pipe 80b is connected to the third liquid It is connected to the side communication pipe L3. As a result, for example, one of the indoor units 40 (specifically 40a and 40b) installed in the target space SP1 and the indoor unit 40 (specifically 40c and 40d) installed in the target space SP2 When the other side is in a stopped state when the operating state is normal cycle operation, the trap portion T1 of the branch pipe 80 communicating with the other (stopped indoor unit) at the liquid side branch portion BL1 leads to the stopped indoor unit side. The refrigerant is restrained from flowing. In relation to this, a situation in which the amount of refrigerant circulation is insufficient in the indoor unit is suppressed, and a decrease in reliability is suppressed.

In addition, in the present embodiment, the first branch pipe 80a (see FIG. 9) located on the rear side in the installed state is the second liquid side communication pipe L2 ( 1 and 2). In addition, the second branch pipe 80b (see FIG. 9) arranged on the front side in the installed state is the third liquid side communication pipe L3 (see FIGS. 1 and 2) communicating with the indoor units 40c and 40d installed in the target space SP2. ) are connected.

The installation location of the second branch pipe unit 60 and the configuration mode and components of the trap portion T1 are instructed to the serviceman who performs the installation by means of an installation manual or the like.

(6) Construction of the second branch pipe unit 60 The second branch pipe unit 60 is pre-assembled and carried to the construction site. The second branch pipe unit 60 is installed at the construction site by being joined to other connecting pipes (CP1, CP2). At this time, the branch pipe 80 is appropriately cut as necessary so as to suit the installation environment and the like, and then joined to other connecting pipes. The installation method for the second branch pipe unit 60 is instructed to the serviceman who performs the installation by means of an installation manual or the like.

(7) Features (7-1)
In the second branch pipe unit 60 according to the above-described embodiment, workability is improved.

Conventionally, in an air conditioning system having an outdoor unit and a plurality of indoor units, the liquid-side refrigerant flow path between the outdoor unit and the indoor unit is configured by a refrigerant communication pipe. A case where it is necessary to provide a trap is assumed.

For example, a refrigerant communication pipe usually includes a number of branch pipes corresponding to the number of indoor units. If there are restrictions on the construction of the refrigerant communication pipes due to (beams in the space above the ceiling, etc.), some branch pipes may have a lower installation height than other branch pipes or may have a steep downward slope. In such a case, it may be necessary to provide a trap in the refrigerant communication pipe in order to suppress the drift and stagnation of the refrigerant.

Further, for example, when performing gas-liquid two-phase transfer as in Patent Document 1, since the amount of refrigerant charged is smaller than usual, the branch pipe communicating with the indoor unit in the operation stopped state (stopped indoor unit) is in a liquid state. It is conceivable that the refrigerant that is not filled with refrigerant and should be sent to the operating indoor unit (operating unit) flows from the branch portion into the branch pipe that communicates with the stopped indoor unit. In particular, when the branch pipe communicating with the stop indoor unit is installed at a lower height than the branch pipe communicating with the operating unit or has a steep downward slope, the refrigerant tends to flow into the branch pipe communicating with the stop indoor unit. For this reason, when performing gas-liquid two-phase transfer, in order to prevent the situation in which the refrigerant flows in and stays in the stopped indoor unit, and the refrigerant circulation amount in the operating unit is not ensured normally, a trap is placed in the refrigerant communication pipe. may need to be provided.

On the other hand, such a refrigerant communication pipe is usually installed in a narrow space such as a ceiling space where it is constructed by a serviceman at a construction site. For this reason, the labor and time required to install the trap at the construction site tend to be large, and there are cases where the workability is not excellent.

The second branch pipe unit 60 (corresponding to the “piping unit”) in the above embodiment is connected to the liquid side connecting pipe La (corresponding to the “refrigerant connecting pipe”), and together with the liquid side connecting pipe La, the liquid side connecting circuit RC3a ( A second branch pipe unit 60 that forms a “liquid-side refrigerant channel” and branches or merges the refrigerant, and includes a plurality of branch pipes 80 and a main pipe 70 . The liquid side connecting pipe La forms a liquid side connecting circuit RC3a between the outdoor unit 10 and the plurality of indoor units 40 . The main pipe 70 communicates with each branch pipe 80 . The main pipe 70 forms a flow path for the refrigerant flowing to each branch pipe 80 or for the refrigerant flowing from each branch pipe 80 . The main pipe 70 is positioned closer to the outdoor unit 10 than the branch pipe 80 in the liquid side communication circuit RC3a in the installed state. The main pipe 70 includes a first main pipe portion 71 (corresponding to "first portion"). The first main pipe portion 71 extends along the x direction (corresponding to the “first direction”). At least one branch tube 80 includes a second extension 82 (corresponding to a "second portion"). The second extending portion 82 extends along the y direction (corresponding to the “second direction”). The y-direction is a direction crossing the x-direction. The x direction is the horizontal direction in the installed state. The y direction is the vertical direction in the installed state.

In the second branch pipe unit 60 in the above embodiment, the liquid side connecting pipe La and the liquid side connecting circuit RC3a are formed between the outdoor unit 10 and the plurality of indoor units 40, and the main pipe 70 extends in the x direction (horizontal in the installed state). direction), and at least one branch pipe 80 includes a second extension portion 82 extending along the y-direction (the vertical direction in the installed state) intersecting the x-direction. Thereby, in the installed state, the second extending portion 82 of the branch pipe 80 extends along the vertical direction and can function as a trap portion T1 (trap). In other words, the trap section T1 can be easily configured by appropriately connecting the main pipe 70 and each branch pipe 80 of the second branch pipe unit 60, which functions as a "trap component", to the liquid side connecting pipe La at the construction site. Therefore, in the case where it is necessary to provide the trap portion T1 in the liquid-side communication pipe La forming the liquid-side communication channel, it is necessary to bend or connect the pipe so as to configure the trap portion T1 at the construction site. Less work. As a result, even when the liquid-side connecting pipe La is installed in a narrow space, the labor and time required for the operation of providing the trap portion T1 can be reduced. Therefore, the improvement of enforceability is promoted.

It should be noted that "extending along the x direction" here means not only the state in which the extending direction necessarily matches the x direction (horizontal direction in the installed state), but also the state in which the extending direction is slightly inclined with respect to the x direction. Also includes For example, a state of being inclined within a range of a predetermined angle (for example, 30 degrees) with respect to the x-direction is interpreted as "extending along the x-direction".

Moreover, "extending along the y-direction" includes not only the state in which the extending direction necessarily coincides with the y-direction (the vertical direction in the installed state), but also the state in which the extending direction is slightly inclined with respect to the y-direction. For example, a state of being inclined within a range of a predetermined angle (for example, 30 degrees) with respect to the y direction is interpreted as "extending along the y direction".

(7-2)
In the above embodiment, at least one branch pipe 80 includes the third extending portion 84 (corresponding to the “third portion”) and the folded portion 83 (corresponding to the “folded portion”). The third extending portion 84 is located closer to the indoor unit 40 than the second extending portion 82 (corresponding to the "second portion") in the liquid side communication circuit RC3a (corresponding to the "liquid side refrigerant flow path") in the installed state. do. The third extending portion 84 extends along the y direction. The folded portion 83 is positioned between the second extending portion 82 and the third extending portion 84 in the liquid side communication circuit RC3a in the installed state. The folded portion 83 connects the second extending portion 82 and the third extending portion 84 . As a result, the labor and time required for the work of providing the trap portion T1 are particularly reduced. Therefore, improvement of enforceability is particularly promoted.

(7-3)
In the above embodiment, at least one branch tube 80 includes a fourth extending portion 85 (corresponding to a "fourth portion"). The fourth extending portion 85 is located closer to the indoor unit 40 than the third extending portion 84 (corresponding to the "third portion") in the liquid-side communication circuit RC3a (corresponding to the "liquid-side refrigerant channel") in the installed state. . The fourth extending portion 85 extends along the x direction. This makes it possible to connect the end of the main pipe 70 and the end of the branch pipe 80 of the second branch pipe unit 60 to the liquid side connecting pipes La (CP1, CP2) extending horizontally at the construction site. there is Therefore, when the liquid-side connecting pipe La is installed in a narrow space, the labor and time required for the operation of providing the trap portion T1 are particularly reduced, and the workability is particularly improved.

(7-4)
In the above embodiment, at least one branch tube 80 includes a first extending portion 81 (corresponding to the "fifth portion"). The first extending portion 81 is positioned closer to the outdoor unit 10 than the second extending portion 82 (corresponding to the "second portion") in the liquid side communication circuit RC3a (corresponding to the "liquid side refrigerant flow path") in the installed state. . The first extending portion 81 extends along the x direction. As a result, the labor and time required for the work of providing the trap portion T1 are particularly reduced. Therefore, improvement of enforceability is particularly promoted.

(7-5)
In the above embodiment, the x-direction and the y-direction intersect substantially at right angles. As a result, the main pipe 70 and each of the branch pipes 80 are connected to the liquid-side communication pipe La, so that the trap portion T1 can be configured more simply. Therefore, even when the liquid-side connecting pipe La is installed in a narrow space, the labor and time required for the operation of providing the trap portion T1 are particularly reduced, and the workability is particularly improved.

It should be noted that the term "substantially perpendicularly intersect" here means not only the case where the x direction and the y direction intersect at 90 degrees, but also the case where the x direction and the y direction intersect at a slight angle to 90 degrees. Including cases. Specifically, when the x-direction and the y-direction intersect within a predetermined angle range (for example, 60 degrees or more and 120 degrees or less), it is interpreted as "substantially perpendicular intersection".

(7-6)
In the above embodiment, the size of the branch pipe 80 is 2 minutes or more and 6 minutes or less. As a result, when the liquid-side communication circuit RC3a (liquid-side refrigerant channel) is formed by using the branch pipe 80 having a general size, the trap portion T1 can be configured more easily. It has become so.

(7-7)
In the above embodiment, the refrigerant flowing from the outdoor unit 10 to the indoor unit 40 through the liquid side communication circuit RC3a (corresponding to the "liquid side refrigerant flow path") flows into the liquid side communication circuit RC3a in a gas-liquid two-phase state. . As a result, in an air-conditioning system that performs gas-liquid two-phase transport (that is, when it is particularly necessary to provide the trap portion T1 in the liquid side connecting pipe La), the labor and time required for the work of providing the trap portion T1 are reduced, Enforceability is being promoted.

(7-8)
The air conditioning system 100 according to the above embodiment includes an outdoor unit 10, a plurality of indoor units 40, a liquid side communication pipe La (corresponding to a "refrigerant communication pipe"), and a second branch pipe unit 60 (a "piping unit"). equivalent), and

(8) Modifications The above embodiment can be appropriately modified as shown in the following modifications. Each modified example may be applied in combination with other modified examples as long as there is no contradiction.

(8-1) Modification 1
In the second branch pipe unit 60 in the above embodiment, each branch pipe 80 (first branch pipe 80a and second branch pipe 80b) included in the branch pipe group 88 has a first extending portion 81, a second extending portion 82, a folded portion 83, It had a third extension 84 and a fourth extension 85, respectively. That is, each branch pipe 80 has a rising portion V1 (that is, a trap portion T1). However, each branch pipe 80 does not necessarily have the first extension portion 81, the second extension portion 82, the folded portion 83, the third extension portion 84, and the fourth extension portion 85, respectively. That is, each branch pipe 80 does not need to have a rising portion V1 (that is, a trap portion T1).

For example, the second branch pipe unit 60 may be configured like the second branch pipe unit 60a (corresponding to the "branch pipe unit") shown in FIG. FIG. 10 is a schematic configuration diagram of the second branch pipe unit 60a. In FIG. 10, the two-dot chain line arrow indicates the direction of flow of the refrigerant during normal cycle operation. In the following, portions of the second branch pipe unit 60a that are different from the second branch pipe unit 60 will be described.

The second branch pipe unit 60a has a first branch pipe 80a' and a second branch pipe 80b' instead of the first branch pipe 80a and the second branch pipe 80b. Unlike the first branch pipe 80a, the first branch pipe 80a' does not have the first extending portion 81, the second extending portion 82, the folded portion 83, the third extending portion 84, and the fourth extending portion 85, respectively. In relation to this, the rising portion V1 (that is, the trap portion T1) is not arranged in the first branch pipe 80a'.

In addition, in the second branch pipe 80b', the dimension in the y direction of the third extending portion 84 is larger than that in the second branch pipe 80b. In this regard, in the installed state, the installation height of the fourth extending portion 85 and the indoor unit side connecting pipe CP2 connected to the fourth extending portion 85 is lower than the first branch pipe 80a'. That is, the second branch pipe 80b' has a lower installation height than the first branch pipe 80a'. That is, in the second branch pipe unit 60a, the trap portion T1 includes a branch pipe 80 (second branch pipe 80b') including a portion of the branch pipe group 88 whose installation height is lower than that of the other branch pipe 80 (first branch pipe 80a'). is configured to be provided in

Even when such a second branch pipe unit 60a is arranged in place of the second branch pipe unit 60, when some indoor units 40 are in operation and other indoor units 40 are in operation stop state, The trap portion T1 (of the second branch pipe 80b' communicating with the stop indoor unit) is filled with gas refrigerant. In particular, when the branch pipe 80 (here, the second branch pipe 80b') communicating with the stop indoor unit is installed at a lower height than the branch pipe 80 (here, the first branch pipe 80a') communicating with the operation unit, or the downward slope is large. Even in the case of including the portion, the refrigerant is appropriately suppressed from flowing into the branch pipe 80 (here, the second branch pipe 80b') communicating with the stopped indoor unit. As a result, the refrigerant is suppressed from flowing to the side of the stopped indoor unit that communicates with the second branch pipe 80b'. Therefore, the shortage of the refrigerant circulation amount in the indoor unit communicating with the first branch pipe 80a' is suppressed.

In addition, by using the second branch pipe unit 60a, the trap portion T1 can be easily configured at the construction site. Therefore, even when the liquid-side connecting pipe La is installed in a narrow space, the labor and time required for the operation of installing the trap are reduced, and workability is improved.

The fact that each branch pipe 80 does not need to have a rising portion V1 (that is, a trap portion T1) also applies to second branch pipe units 60b to 60g (see FIGS. 11 to 18), which will be described later. is.

(8-2) Modification 2
The second branch pipe unit 60 may be configured like the second branch pipe unit 60b shown in FIG. 11, for example. FIG. 11 is a schematic configuration diagram of the second branch pipe unit 60b. In FIG. 11, the two-dot chain line arrow indicates the direction of flow of the refrigerant during normal cycle operation. In the following, portions of the second branch pipe unit 60b that are different from the second branch pipe unit 60 will be described.

In the second branch pipe unit 60b, the branch pipe group 88 has a branch pipe 80A instead of the branch pipe 80. As shown in FIG. Unlike the branch pipe 80, the branch pipe 80A has a first extending portion 81', a second extending portion 82', a folded portion 83', a third extending portion 84' and a fourth extending portion 85'. In the branch pipe 80</b>A, the inclination angle of the second extending portion 82 ′ with respect to the x-direction is smaller than that of the second extending portion 82 of the branch pipe 80 . Also, the inclination angle of the third extending portion 84 ′ with respect to the x-direction is smaller than that of the third extending portion 84 of the branch pipe 80 . In this connection, the branch tube 80A is folded back in a helical shape. That is, the branch pipe 80A is folded back 360 degrees between one end 801 and the other end 802, with a first extending portion 81', a second extending portion 82', a folded portion 83', a third extending portion 84', and a fourth extending portion 84'. An elongated portion 85' is formed and associated therewith a trap portion T1 including a rising portion V1.

Even when such a second branch pipe unit 60b is arranged instead of the second branch pipe unit 60, the same effects as those of the above-described embodiment can be obtained.

Also, in the second branch pipe unit 60b, at least one branch pipe 80A is folded back in a spiral shape. As a result, the end portion of the main pipe 70 of the second branch pipe unit 60 on the side of the outdoor unit 10 and the end portion of the branch pipe 80A on the side of the indoor unit 40 are connected to liquid side connecting pipes La (CP1, CP2) extending in the horizontal direction at the construction site. ) can be connected. Therefore, when the liquid-side connecting pipe La is installed in a narrow space, the labor and time required for the operation of providing the trap portion T1 are particularly reduced, and the workability is particularly improved.

(8-3) Modification 3
The second branch pipe unit 60 may be configured like the second branch pipe unit 60c shown in FIG. 12, for example. FIG. 12 is a schematic configuration diagram of the second branch pipe unit 60c. In FIG. 12, the two-dot chain line arrow indicates the direction of flow of the refrigerant during normal cycle operation. In the following, portions of the second branch pipe unit 60c that are different from the second branch pipe unit 60 will be described.

The second branch pipe unit 60c has a connection pipe portion 90A instead of the connection pipe portion 90. As shown in FIG. Unlike the connection pipe portion 90, the connection pipe portion 90A is arranged so as to extend in the y-direction (that is, the direction intersecting the extending direction of the main pipe 70 and upward in the installed state). That is, the connection pipe portion 90A is connected to the main pipe 70 and the branch pipe group 88 so as to have a substantially U-shape or substantially C-shape when viewed from the x direction.

Further, in the second branch pipe unit 60c, the branch pipe group 88 has a branch pipe 80B instead of the branch pipe 80. As shown in FIG. Unlike the branch pipe 80, the branch pipe 80B does not have the first extending portion 81. As shown in FIG. Further, the branch pipe 80B has a second extending portion 82a having a smaller dimension in the y direction than the second extending portion 82 instead of the second extending portion 82. As shown in FIG.

In the second branch pipe unit 60c, the rising portion V1 and the trap portion T1 are configured by the connecting pipe portion 90A together with the branch pipe 80B. That is, in the second branch pipe unit 60c, the extension direction of the main pipe 70 is the x direction (horizontal direction in the installed state), the extension direction of the connection pipe portion 90A is the y direction (vertical direction in the installed state), and the rising portion V1 is arranged across the connecting tube portion 90A and the corresponding branch tube 80B. Even when such a second branch pipe unit 60c is arranged instead of the second branch pipe unit 60, the same effects as those of the above-described embodiment can be obtained.

(8-4) Modification 4
The second branch pipe unit 60c may be configured like the second branch pipe unit 60d shown in FIG. 13, for example. FIG. 13 is a schematic configuration diagram of the second branch pipe unit 60d. In FIG. 13, the two-dot chain line arrow indicates the direction of flow of the refrigerant during normal cycle operation. In the following, the second branch pipe unit 60d will be described with respect to portions that are different from the second branch pipe unit 60c.

The second branch pipe unit 60d has a main pipe 70A instead of the main pipe 70. As shown in FIG. The main pipe 70A includes a first main pipe portion 71 extending along the x direction (“horizontal direction” in the installed state) and a second main pipe portion 72 extending along the y direction (“vertical direction” in the installed state). corresponding to the "sixth part" in the scope). The end of the first main pipe portion 71 constitutes one end 701' of the main pipe 70A, and is connected to the outdoor unit side communication pipe CP1 in the installed state. The distal end of the first main pipe portion 71 is connected to the distal end of the second main pipe portion 72 . The second main pipe portion 72 is positioned between the first main pipe portion 71, the connection pipe portion 90A and the second extending portion 82a. The tip of the second main pipe portion 72 constitutes the other end 702' of the main pipe 70A and is connected to the connection pipe portion 90A. That is, the main pipe 70A extends from one end 701' along the x direction and then extends in the y direction to be connected to the connecting pipe portion 90A. In relation to this, in the second branch pipe unit 60d, the rising portion V1 and the trap portion T1 are composed of the branch pipe 80B, the connection pipe portion 90A and the main pipe 70A (second main pipe portion 72). That is, in the second branch pipe unit 60d, the extending direction of the main pipe 70A and the connecting pipe portion 90A is the y direction (the vertical direction in the installed state), and the rising portion V1 extends along the main pipe 70A, the connecting pipe portion 90A, and the corresponding branch pipe 80B. placed across.

In the second branch pipe unit 60d, the main pipe 70A includes a second main pipe portion 72 (corresponding to "sixth portion") extending along the y direction, and the second main pipe portion 72 is a first main pipe portion 71 ("first portion”) and the second extending portion 82a (corresponding to the “second portion”). Even when such a second branch pipe unit 60d is arranged instead of the second branch pipe unit 60, the same effects as those of the above-described embodiment can be obtained.

The second branch pipe unit 60d may have the first main pipe portion 71 omitted from the main pipe 70A, like the second branch pipe unit 60d' shown in FIG. In this case, the end of the second main pipe portion 72 constitutes one end 701' of the main pipe 70A, and is connected to the outdoor unit side communication pipe CP1 in the installed state.

(8-5) Modification 5
The second branch pipe unit 60d may be configured like the second branch pipe unit 60e shown in FIG. 15, for example. FIG. 15 is a schematic configuration diagram of the second branch pipe unit 60e. In FIG. 15, the two-dot chain line arrow indicates the direction of flow of the refrigerant during normal cycle operation. In the following, the second branch pipe unit 60e will be described with respect to portions that are different from the second branch pipe unit 60d.

The second branch pipe unit 60e has a main pipe 70B instead of the main pipe 70A, and a connection pipe portion 90B (corresponding to the “connection pipe” described in the claims) instead of the connection pipe portion 90A. there is

The main pipe 70B extends along the x direction (horizontal direction in the installed state) and then along the y direction (the downward direction in the installed state). and a fourth main pipe portion 74 extending in the y direction (downward direction in the installed state) on the branch pipe group 88 side of the third main pipe portion 73 (the “seventh portion” and the “eighth portion” in the claims). (equivalent to "part"), and The end of the third main pipe portion 73 constitutes one end 701'' of the main pipe 70B, and is connected to the outdoor unit side communication pipe CP1 in the installed state. The distal end of the third main pipe portion 73 is connected to the distal end of the fourth main pipe portion 74 . The tip of the fourth main pipe portion 74 constitutes 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). That is, the main pipe 70B extends along the x direction from one end 701'', and then extends in the y direction and is connected to the connecting pipe portion 90B at the other end 702''.

FIG. 16 is an enlarged view of the connection pipe portion 90B and its surroundings in the second branch pipe unit 60e. As shown in FIG. 16, the connection pipe portion 90B extends along the x-direction and/or the z-direction (horizontal direction in the installed state) and branches according to the number of the branch pipes 80B included in the branch pipe group 88. , has a connecting pipe extending portion 91 that extends by folding back in the y direction (upward direction in the installed state) at each branch destination and is connected to the second extending portion 82a of the branch pipe 80B. The connecting pipe extending portion 91 is a portion in which the refrigerant flowing from the main pipe 70B is turned upward in the second branch pipe unit 60e. The connection tube portion 90B has a plurality of ends 902', and each end 902' is connected to the second extending portion 82a of one of the branch tubes 80B. The connection pipe portion 90B connects the ends of the branch pipes 80B included in the branch pipe group 88 (the ends on the main pipe 70 side).

In the second branch pipe unit 60e, the rising portion V1 and the trap portion T1 are configured by the branch pipe 80B and the connection pipe portion 90B (connection pipe extending portion 91). That is, in the second branch pipe unit 60e, the main pipe 70B extends along the y-direction (downward direction in the installed state), and the connection pipe portion 90B includes a connection pipe extending portion 91 that bends upward the refrigerant flowing from the main pipe 70B. , the rising portion V1 is arranged across the connecting pipe portion 90B and the corresponding branch pipe 80B.

The second branch pipe unit 60e includes a connecting pipe portion 90B (corresponding to a "connecting pipe"). In the second branch pipe unit 60e, each branch pipe 80 includes a second extending portion 82a (corresponding to "second portion"). The connecting pipe portion 90B connects the ends of the second extending portions 82a on the outdoor unit 10 side. The main pipe 70 includes a fourth main pipe portion 74 (corresponding to "eighth portion"). The fourth main pipe portion 74 is positioned closer to the indoor unit 40 than the first main pipe portion 71 in the liquid side communication circuit RC3a (corresponding to the "liquid side refrigerant flow path") in the installed state. The connection pipe portion 90B extends along the x direction. The connecting tube portion 90B has a plurality of end portions 902'. An end portion 902' of the connecting pipe portion 90B is connected to one of the second extending portions 82a. The fourth main pipe portion 74 extends along the y direction. The end portion of the fourth main pipe portion 74 on the indoor unit 40 side is connected between the end portions of the connecting pipe portion 90B. The refrigerant flowing from the outdoor unit 10 to the indoor unit 40 flows downward in the fourth main pipe portion 74 in the installed state. The refrigerant flowing from the outdoor unit 10 to the indoor unit 40 flows upward in the second extending portion 82a in the installed state. Even when such a second branch pipe unit 60e is arranged instead of the second branch pipe unit 60, the same effects as those of the above-described embodiment can be obtained.

(8-6) Modification 6
The second branch pipe unit 60e may be configured like the second branch pipe unit 60f shown in FIG. 17, for example. FIG. 17 is a schematic configuration diagram of the second branch pipe unit 60f. In FIG. 17, the two-dot chain line arrow indicates the direction of flow of the refrigerant during normal cycle operation. In the following, the second branch pipe unit 60f will be described with respect to portions that are different from the second branch pipe unit 60e.

In the second branch pipe unit 60f, unlike the second branch pipe unit 60e, the connection pipe portion 90B is omitted. Also, the second branch pipe unit 60f has a main pipe 70B' instead of the main pipe 70B. The main pipe 70B′ has 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 extends in the y direction (downward direction in the installed state) on the branch pipe group 88 side of the third main pipe portion 73, and then extends in the x direction and/or the z direction (horizontal direction in the installed state). branched according to the number of branch pipes 80B included in the branch pipe group 88, and then folded back and extended in the y direction (upward direction in the installed state) at each branch destination to be connected to the second extending portion 82a of the branch pipe 80B. This is the part where In the second branch pipe unit 60f, the fifth main pipe portion 75 includes a portion extending along the x direction and corresponds to the "first portion" described in the claims.

In addition, the fourth main pipe portion 74 is positioned closer to the outdoor unit 10 than the fifth main pipe portion 75 in the liquid side communication circuit RC3a in the installed state. In addition, in the second branch pipe unit 60f, the refrigerant flowing from the outdoor unit 10 to the indoor unit 40 flows downward in the fourth main pipe portion 74 in the installed state. That is, in the second branch pipe unit 60f, the fourth main pipe portion 74 corresponds to the "seventh portion" described in the claims.

In the second branch pipe unit 60f, the main pipe 70B' includes a third main pipe portion 73 (corresponding to "seventh portion") and a fourth main pipe portion 74 (corresponding to "seventh portion"). The third main pipe portion 73 and the fourth main pipe portion 74 are located closer to the outdoor unit 10 than the fifth main pipe portion 75 (corresponding to the "first portion") in the liquid side communication circuit RC3a in the installed state. The third main pipe portion 73 and the fourth main pipe portion 74 extend along the y direction. The refrigerant flowing from the outdoor unit 10 to the indoor unit 40 flows downward in the third main pipe portion 73 and the fourth main pipe portion 74 in the installed state. The refrigerant flowing from the outdoor unit 10 to the indoor unit 40 flows upward in the second extending portion 82a in the installed state.

Even if the second branch pipe unit 60f is used, the same effects as when the second branch pipe unit 60e is used can be obtained.

(8-7) Modification 7
The second branch pipe unit 60e may be configured like the second branch pipe unit 60g shown in FIG. 18, for example. FIG. 18 is a schematic configuration diagram of the second branch pipe unit 60g. In FIG. 18, the two-dot chain line arrow indicates the direction of flow of the refrigerant during normal cycle operation. In the following, portions of the second branch pipe unit 60g that are different from the second branch pipe unit 60e will be described.

The second branch pipe unit 60g has a main pipe 70C instead of the main pipe 70B. Unlike the main pipe 70B, the main pipe 70C does not have the third main pipe portion 73 . In relation to this, the end of the fourth main pipe portion 74 constitutes one end 701'' of the main pipe 70B, and is connected to the outdoor unit side communication pipe CP1 in the installed state.

In the second branch pipe unit 60g, similarly to the second branch pipe unit 60e, the rising portion V1 and the trap portion T1 are configured by the branch pipe 80B and the connecting pipe portion 90B. Even when the second branch pipe unit 60g is arranged in place of the second branch pipe unit 60, the same effects as those of the above embodiment can be obtained.

(8-8) Modification 8
In the above embodiment, the case where the second branch pipe unit 60 constitutes the liquid side branch portion BL1, which is the liquid side branch portion BPa closest to the outdoor unit 10, has been described. However, the branch portion BP configured by the second branch pipe unit 60 may be appropriately selected in consideration of the necessity of configuring the trap portion T1 according to the design specifications and installation environment. For example, any or all of the liquid side branch portions BL2, BL3, BL4, BL5, and BL6 shown in FIG.

(8-9) Modification 9
The second extending portion 82 does not necessarily have to extend perpendicularly to the extending direction of the first extending portion 81 or the main pipe 70 . That is, the inclination angle of the second extending portion 82 with respect to the extending direction of the first extending portion 81 or the main pipe 70 may be an angle smaller than 90 degrees. For example, the second extending portion 82 may extend along the y direction at an inclination angle of 30 to 60 degrees with respect to the extending direction of the first extending portion 81 or the main pipe 70 .

(8-10) Modification 10
In the above-described embodiment, the second branch pipe unit 60 is configured by joining the main pipe 70, the connecting pipe portion 90, and the branch pipes 80, which are separately formed. However, the second branch pipe unit 60 may be configured by integrally molding any one or all of the main pipe 70, the connection pipe portion 90, and the branch pipes 80. As shown in FIG. For example, it may be constructed by bending a single pipe. Further, for example, the second branch pipe unit 60 may be configured by joining a plurality of pipes.

(8-11) Modification 11
The configuration of each of the main pipe 70, the connection pipe portion 90, and the branch pipes 80 included in the second branch pipe unit 60 may be selected as appropriate. That is, each of the main pipe 70, the connecting pipe portion 90, and each of the branch pipes 80 may be configured by bending a single pipe, or may be configured by joining a plurality of pipes.

(8-12) Modification 12
In the above embodiment, the case where the second branch pipe unit 60 constitutes all of the predetermined branch portions BP has been described. However, the second branch pipe unit 60 does not necessarily constitute the entire branch portion BP, and may constitute only a part of the branch portion BP. That is, the second branch pipe unit 60 may constitute the branch portion BP together with other pipes (for example, one or all of the outdoor unit side connecting pipe CP1 and the indoor unit side connecting pipe CP2, or other pipe units). good.

(8-13) Modification 13
In the above embodiment, the case where the second branch pipe unit 60 is pre-assembled and brought into the construction site has been described. However, it is not limited to this, and the second branch pipe unit 60 may be assembled by joining or removing each part at the construction site. For example, the second branch pipe unit 60 is assembled by joining any/all of the main pipe 70, the connecting pipe portion 90, and each branch pipe 80 separated from other parts to other parts at the construction site. may be Further, for example, the second branch pipe unit 60 may be assembled by cutting off any/all of the main pipe 70, the connecting pipe portion 90, and the branch pipes 80 at the construction site as required.

Also, for example, any/all of the parts included in the main pipe 70 may be assembled by being joined to other parts included in the main pipe 70 at the construction site. Also, for example, any/all of the portions included in the main pipe 70 may be assembled by being cut off as necessary at the construction site.

Further, for example, any/all of the portions included in the connecting pipe portion 90 may be assembled by being joined to other portions included in the main pipe 70 at the construction site. Further, for example, any/all of the portions included in the connecting pipe portion 90 may be assembled by being cut off as necessary at the construction site.

Also, for example, any/all of the portions (eg, 81 to 85) included in the branch pipe 80 may be assembled by being joined to other portions included in the main pipe 70 at the construction site. Also, for example, any/all of the portions (eg, 81-85) included in the branch pipe 80 may be cut and assembled at the construction site as required.

(8-14) Modification 14
In the above embodiment, the case where the branch pipe 80 is composed of the first extending portion 81, the second extending portion 82, the folded portion 83, the third extending portion 84, and the fourth extending portion 85 has been described. However, the configuration mode of the branch pipe 80 is not necessarily limited to this, and can be changed as appropriate as long as there is no contradiction with the effects of the above-described embodiment. For example, the branch pipe 80 may not have any/all of the first extension portion 81 , the folded portion 83 , the third extension portion 84 and the fourth extension portion 85 . Further, for example, the branch pipe 80 may additionally have portions other than the first extending portion 81 , the folded portion 83 , the third extending portion 84 and the fourth extending portion 85 .

(8-15) Modification 15
In the above embodiment, the case where the branch pipe 80 is configured with a size of 2 minutes or more and 6 minutes or less has been described. In this regard, the inner diameter and/or outer diameter of the branch tube 80 does not necessarily have to be uniform from one end to the other end, and may have a portion that partially expands or contracts.

(8-16) Modification 16
In the above embodiment, the x direction corresponds to the horizontal direction in the installed state, and the z direction corresponds to the front and rear direction in the installed state. However, without being limited to this, the x direction may correspond to the front-back direction in the installed state, and the z direction may correspond to the left-right direction in the installed state.

(8-17) Modification 17
The installation mode of the second branch pipe unit 60 shown in FIG. 7 is merely an example, and can be changed as appropriate according to the design specifications and installation environment. Or it may be inverted upside down.

(8-18) Modification 18
In the above embodiment, the branch pipe group 88 in the second branch pipe unit 60 has two branch pipes 80 (80a, 80b). However, the branch tube group 88 may have three or more branch tubes 80 . In such a case, the rising portion V1 (upwardly extending portion) may be appropriately configured in a predetermined branch pipe 80 according to design specifications and installation environment.

(8-19) Modification 19
The configuration mode of the refrigerant circuit RC in the above embodiment is not necessarily limited to the mode shown in FIG. 1, and can be changed as appropriate according to design specifications and installation environment.

For example, the first outdoor control valve 16 is not necessarily required and can be omitted as appropriate. In such a case, the second outdoor control valve 17 may have the function of the first outdoor control valve 16 during reverse cycle operation.

Further, for example, the second outdoor control valve 17 does not necessarily have to be arranged inside the outdoor unit 10, and may be arranged outside the outdoor unit 10 (for example, on the liquid-side connecting pipe La).

Further, for example, the indoor expansion valve 41 does not necessarily have to be arranged inside the indoor unit 40, and may be arranged outside the indoor unit 40 (for example, on the liquid-side connecting pipe La).

Also, for example, the supercooler 15 and the third outdoor control valve 18 are not necessarily required, and may be omitted as appropriate. Also, equipment not shown in FIG. 1 may be newly added.

Further, for example, the refrigerant circuit RC includes a refrigerant flow switching unit that switches the flow of refrigerant flowing into each indoor unit 40 so that each indoor unit 40 can perform forward cycle operation and reverse cycle operation separately. may be arranged between the outdoor unit 10 and each indoor unit 40 .

(8-20) Modification 20
In the air conditioning system 100 of the above-described embodiment, a plurality of (four or more) indoor units 40 are connected in series or parallel to one outdoor unit 10 via connecting pipes (Ga, La). In this regard, the number of the outdoor units 10 and/or the indoor units 40 and their connection mode can be appropriately changed according to the installation environment and design specifications. For example, a plurality of outdoor units 10 may be arranged in series or in parallel.

(8-21) Modification 21
In the above embodiment, R32 was used as the refrigerant circulating in the refrigerant circuit RC. However, the refrigerant used in the refrigerant circuit RC is not particularly limited, and other refrigerants may be used. For example, in the refrigerant circuit RC, an HFC refrigerant such as R407C or R410A may be used.

(8-22) Modification 22
The present invention was applied to the air conditioning system 100 in the above embodiment. However, the present invention is not limited to this, and can also be applied to other refrigerating apparatuses having a refrigerant circuit (for example, water heaters, heat pump chillers, etc.).

(8-23) Modification 23
In the above-described embodiment, the second branch pipe unit 60 is applied to the air conditioning system 100 that performs gas-liquid two-phase transport during normal cycle operation. However, the second branch pipe unit 60 is not necessarily prevented from being applied to an air conditioning system that conveys liquid.

(9)
Although embodiments of the invention have been described above, it will be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the appended claims. .

The present disclosure is applicable to plumbing units or air conditioning systems.

10: Outdoor unit 40: Indoor units 40a, 40b: Indoor units 40c, 40d: Indoor unit 50: Branch pipe unit 51: First branch pipe unit 60, 60a-60g: Second branch pipe unit (piping unit)
70, 70A, 70B, 70B', 70C: main pipe 71: first main pipe portion (first portion)
72: Second main section (sixth section)
73: Third main section (seventh part)
74: 4th main section (7th part, 8th part)
75: Fifth main section (first part)
80, 80A, 80B: branch pipes 80a, 80a': first branch pipes 80b, 80b': second branch pipes 81, 81': first extending portion (fifth portion)
82, 82', 82a: Second extending portion (second portion)
83, 83': folded portion (folded portion)
84, 84': third extending portion (third portion)
85, 85': fourth extending portion (fourth portion)
88: branch pipe group 90, 90A, 90B: connecting pipe part (connecting pipe)
91: connecting pipe extension 95: heat insulating material 100: air conditioning system 701, 701', 701'': one end of main pipe 702, 702', 702'': other end of main pipe 801: one end of branch pipe 802: other end of branch pipe 901: first connection portion 902: second connection portion 902': end portion of connection pipe portion (end portion of connection pipe)
B1: Building BP: Branching portion BPa, BL1-BL6: Liquid side branching portion BPb: Gas side branching portion C1: Ceiling bottom surface C2: Ceiling top surface CP1: Outdoor unit side connecting pipe CP2: Indoor unit side connecting pipe G: Gas reservoir Ga: Gas side connecting pipe G1-G5: 1st gas side connecting pipe - 5th gas side connecting pipe La: Liquid side connecting pipe (refrigerant connecting pipe)
L1-L5: 1st liquid side connecting pipe - 5th liquid side connecting pipe P1-P14: 1st pipe - 14th pipe RC: Refrigerant circuit RC1: Outdoor circuit RC2: Indoor circuit RC3: Communication circuit RC3a: Liquid side Communication circuit (liquid side refrigerant flow path)
RC3b: gas side communication circuit SP, SP1, SP2: target space SPa: ceiling space T1: trap section V1: rising section

International Publication No. 2015/029160

Claims (9)

It is connected to a refrigerant communication pipe (La) that forms a liquid side refrigerant flow path (RC3a) between an outdoor unit (10) and a plurality of indoor units (40), and communicates with the liquid side refrigerant flow path together with the refrigerant communication pipe. A piping unit (60, 60a-60g) that forms and branches or merges the refrigerant,
a plurality of branch pipes (80, 80A, 80B);
A main pipe ( 70, 70A-70C) and
a connecting pipe portion (90) connecting each of the branch pipes and the main pipe;
with
said main pipe includes a first portion (71, 75) extending along a first direction (x);
at least one said branch tube includes a second portion (82, 82', 82a) extending along a second direction (y) crossing said first direction;
The first direction is a horizontal direction in an installed state,
The second direction is a vertical direction in an installed state,
the second portion extends vertically upward in the second direction when viewed from the refrigerant flow direction,
A refrigerant flowing from the outdoor unit to the indoor unit through the liquid-side refrigerant flow path flows into the connecting pipe portion in a gas-liquid two-phase state,
Piping units (60, 60a-60g). at least one branch tube,
a third portion (84, 84') positioned closer to the indoor unit than the second portion in the liquid-side refrigerant channel in the installed state and extending along the second direction;
a folded portion (83, 83') located between the second portion and the third portion in the liquid-side refrigerant channel in an installed state and connecting the second portion and the third portion;
further comprising
The third portion extends vertically downward in the second direction when viewed from the refrigerant flow direction,
Piping unit (60, 60a-60g) according to claim 1. The at least one branch pipe further includes a fourth portion (85, 85') located closer to the indoor unit than the third portion in the liquid-side refrigerant flow path in the installed state,
the fourth portion extends along the first direction;
Piping unit (60, 60a-60g) according to claim 2. The at least one branch pipe further includes a fifth portion (81, 81') located closer to the outdoor unit than the second portion in the liquid-side refrigerant flow path in the installed state,
the fifth portion extends along the first direction,
Piping unit (60, 60a, 60b) according to any one of claims 1 to 3. The main pipe further includes a sixth portion (72) located between the first portion (71) and the second portion (82a),
the sixth portion extends along the second direction,
A piping unit (60d) according to any one of claims 1 to 3. the first direction and the second direction intersect substantially at right angles;
Piping unit (60, 60a-60g) according to any one of claims 1 to 5. The size of the branch tube is 2 minutes or more and 6 minutes or less,
Piping unit (60, 60a-60g) according to any one of claims 1 to 6. the refrigerant flowing from the outdoor unit to the indoor unit through the liquid-side refrigerant channel flows into the liquid-side refrigerant channel in a gas-liquid two-phase state;
Piping unit (60, 60a-60g) according to any one of claims 1 to 7. The outdoor unit (10) according to claim 1;
A plurality of said indoor units (40) according to claim 1;
The refrigerant communication pipe (La) according to claim 1;
the piping unit (60, 60a-60g) according to any one of claims 1 to 8;
comprising
Air conditioning system (100).

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