JP2017003127A - Air conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent gas shortage, to suppress reduction of a supercooling degree of a refrigerant, and to reduce dispersion of cooling capacity by optimizing an amount of refrigerant bypassing a liquid pipe from a high-pressure gas pipe.SOLUTION: An air conditioning device capable of operating a plurality of indoor units 12a, 12b, 12c in one of cooling and heating, and further operating the plurality of indoor units 12a, 12b, 12c in a state of mixing cooling and heating, includes a liquid pipe confluent portion 34 connected to an outdoor unit 11 and the indoor units 12a, 12b, 12c by a high-pressure gas pipe 20, a low-pressure gas pipe 21, and a liquid pipe 22, and disposed between a refrigerant branch portion 22a to the indoor unit 12a closest to the outdoor unit 11 in the liquid pipe 22, and the outdoor unit 11, and a bypass pipe 35 connecting a terminal end portion 33 of the high-pressure gas pipe 20 connected to the indoor unit 12c farthest from the outdoor unit 11, and the liquid pipe confluent portion 34.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an air conditioner.

Having an outdoor unit and a plurality of indoor units, the plurality of indoor units can be operated either by cooling or heating, and the plurality of indoor units are operated by mixing cooling and heating. A possible air conditioner is known (see, for example, Patent Document 1). In such an air conditioner, an outdoor unit including a compressor and an outdoor heat exchanger and a plurality of indoor units including an indoor heat exchanger are connected by inter-unit piping. More specifically, one end of the outdoor heat exchanger is alternatively branched and connected to a refrigerant discharge pipe and a refrigerant suction pipe of the compressor, and the inter-unit pipe is a high-pressure gas pipe connected to the refrigerant discharge pipe. And a low pressure gas pipe connected to the refrigerant suction pipe and a liquid pipe connected to the other end of the outdoor heat exchanger.
In the above configuration, when the heating operation and the cooling operation are mixed and operated, all three refrigerant pipes of the high pressure gas pipe, the low pressure gas pipe, and the liquid pipe are used. When only the cooling operation is performed, the high-pressure gas pipe is not used, and two refrigerant pipes, a low-pressure gas pipe and a liquid pipe, are used. When only the heating operation is performed, the low-pressure gas pipe is not used, and two refrigerant pipes, a high-pressure gas pipe and a liquid pipe, are used.
In the above configuration, when only the cooling operation is performed, the high-pressure gas pipe is not used, but since the high-pressure gas pipe communicates with the refrigerant discharge pipe of the compressor, the refrigerant flowing into the high-pressure gas pipe remains at a high pressure. It can be cooled by the outside air temperature, condensed in the high-pressure gas pipe, and accumulated in a liquid state. In this case, the amount of refrigerant in the system is insufficient by the amount accumulated in the high-pressure gas pipe, and the efficiency decreases due to lack of gas.
In Patent Document 1, by providing bypass means for bypassing the high-pressure gas pipe to the liquid pipe for each indoor unit, the liquid refrigerant accumulated in the high-pressure gas pipe during the cooling operation is taken into the liquid pipe to prevent the occurrence of gas shortage. doing.

JP 2001-336858 A

However, in the conventional air conditioner, during the cooling operation, the refrigerant flowing from the high-pressure gas pipe to the liquid pipe through the bypass means merges with the refrigerant that radiates heat by the heat exchanger of the outdoor unit and flows through the liquid pipe. For this reason, the degree of supercooling of the refrigerant decreases, and the cooling performance decreases. Specifically, in the conventional air conditioner, when the number of indoor units installed increases, the number of bypass means also increases, so that the amount of refrigerant flowing through the bypass means can be excessive, and depending on the installation status of the indoor units. However, there is room for improvement because the degree of decrease in the degree of supercooling varies from one indoor unit to another, and the cooling capacity may vary.
The present invention has been made in view of the above-described circumstances. In an air conditioner, the amount of refrigerant bypassed from a high-pressure gas pipe to a liquid pipe is appropriately controlled to prevent out-of-gas, and the refrigerant is supercooled. The purpose is to reduce the variation in cooling capacity while suppressing the decrease in the degree of cooling.

  In order to achieve the above object, the present invention includes an outdoor unit and a plurality of indoor units, the plurality of the indoor units can be operated either by cooling or heating, and a plurality of the units are operated. In an air conditioner capable of operating an indoor unit by mixing cooling and heating, the outdoor unit and the indoor unit are connected by a high pressure gas pipe, a low pressure gas pipe, and a liquid pipe, and the outdoor unit in the liquid pipe A liquid pipe junction between the refrigerant branch to the indoor unit closest to the outdoor unit and the outdoor unit, and the liquid pipe junction and the terminal end of the high-pressure gas pipe connected to the indoor unit farthest from the outdoor unit A bypass pipe is provided to connect the two parts.

Further, the present invention is characterized by comprising a flow rate adjusting means for adjusting the flow rate of the refrigerant in the bypass pipe.
Further, the present invention provides a refrigerant pipe that connects the indoor heat exchanger of the indoor unit and the high-pressure gas pipe, the low-pressure gas pipe, and the liquid pipe, and an open / close that switches a refrigerant flow in the refrigerant pipe according to an operating state. And a housing for housing the refrigerant pipe and the on-off valve. The refrigerant pipe, the on-off valve, and the housing are provided with the refrigerant pipe and the on-off valve of a plurality of the indoor units. Provided as a collective solenoid valve kit integrally provided in the body, one end of the bypass pipe is connected to the terminal portion of the high pressure gas pipe of the collective solenoid valve kit, and the other end of the bypass pipe is connected to the collective solenoid valve kit. The electromagnetic valve kit is connected between the liquid pipe and the outdoor unit.

  According to the air conditioner of the present invention, during the cooling operation, the refrigerant accumulated in the high-pressure gas pipe is returned to the liquid pipe through the bypass pipe, so that the gas shortage can be prevented and the end portion of the high-pressure gas pipe and the liquid pipe merge The bypass pipe connecting the unit can return an appropriate amount of refrigerant to the liquid pipe regardless of the number of indoor units installed, so the reduction in the degree of cooling of the refrigerant is suppressed by reducing the decrease in the degree of supercooling of the refrigerant. be able to. In addition, since the refrigerant returns from the terminal end of the high pressure gas pipe to the liquid pipe junction of the liquid pipe on the indoor unit side closest to the outdoor unit, the temperature difference of the refrigerant flowing from the liquid pipe to each of the indoor units installed in a plurality is set. Can be small. For this reason, the variation in the cooling capacity of each indoor unit can be reduced.

It is a refrigerant circuit figure of the air harmony device concerning an embodiment of the invention. It is a refrigerant circuit figure of the air harmony device at the time of heating operation. It is a refrigerant circuit figure of an air harmony device at the time of mixed operation of air conditioning and heating. It is a refrigerant circuit figure of the air conditioning apparatus of 2nd Embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a refrigerant circuit diagram of the air-conditioning apparatus according to the first embodiment of the present invention.
The air conditioner 10 includes an outdoor unit 11, a plurality of indoor units 12a, 12b, and 12c connected to the outdoor unit 11, and an inter-unit pipe 13 that connects the outdoor unit 11 and the indoor units 12a, 12b, and 12c. Is provided.
The air conditioner 10 includes electromagnetic valve kits 14a, 14b, and 14c that connect the inter-unit pipe 13 and the indoor units 12a, 12b, and 12c, respectively.
The air conditioner 10 is capable of cooling or heating all the indoor units 12a, 12b, and 12c, and is a mixed operation in which the cooling and heating operations are mixed between the indoor units 12a, 12b, and 12c. Is possible.
Here, a configuration in which three indoor units 12a, 12b, and 12c are connected in parallel to the outdoor unit 11 via the inter-unit piping 13 will be described as an example, but the present invention is limited to this. However, two or more indoor units may be connected in parallel.

The outdoor unit 11 includes a compressor 15, switching valves 16 and 17 used for switching between cooling operation, heating operation, and mixed operation of cooling operation and heating operation, an outdoor heat exchanger 18, and an outdoor expansion valve 19. .
The refrigerant pipe connected to one end of the outdoor heat exchanger 18 is branched, and one of the branches is connected to the discharge pipe 15a of the compressor 15 via the switching valve 16, and the other of the branches is connected via the switching valve 17. Are connected to the suction pipe 15b of the compressor 15. That is, in the outdoor unit 11, one end of the outdoor heat exchanger 18 is branched and connected to the discharge pipe 15 a and the suction pipe 15 b of the compressor 15 via the switching valves 16 and 17.
The outdoor expansion valve 19 is provided in the refrigerant pipe at the other end of the outdoor heat exchanger 18. The outdoor unit 11 includes a blower (not shown) that blows air to the outdoor heat exchanger 18 to promote heat exchange. The operation of the switching valves 16 and 17 and the outdoor expansion valve 19 is controlled by a control unit (not shown) of the outdoor unit 11.

  The inter-unit pipe 13 is connected to the discharge pipe 15a of the compressor 15 and extends to the indoor units 12a, 12b, and 12c, and the suction pipe 15b of the compressor 15 is connected to the indoor units 12a, 12b, The low-pressure gas pipe 21 extending toward the 12c side and the liquid pipe 22 connected to the other end of the outdoor heat exchanger 18 and extending toward the indoor units 12a, 12b, and 12c are provided.

The indoor units 12a, 12b, 12c are provided at one end of the indoor heat exchangers 23a, 23b, 23c between the indoor heat exchangers 23a, 23b, 23c and the liquid pipe 22 and the indoor heat exchangers 23a, 23b, 23c. Indoor expansion valves 24a, 24b, and 24c and a blower (not shown) that blows air to the indoor heat exchangers 23a, 23b, and 23c.
The indoor unit 12 a is an indoor unit that is closest to the outdoor unit 11. The indoor unit 12 c is an indoor unit farthest from the outdoor unit 11. The indoor unit 12b is arranged at a position farther from the outdoor unit 11 than the indoor unit 12a and closer to the outdoor unit 11 than the indoor unit 12c.
That is, in the flow of refrigerant supplied from the outdoor unit 11 through the inter-unit pipe 13, the indoor unit 12a is located on the most upstream side, and the indoor unit 12c is located on the most downstream side.

The solenoid valve kits 14a, 14b, and 14c branch from the refrigerant branch portions 22a, 22b, and 22c of the liquid pipe 22 and are connected to one end sides of the indoor heat exchangers 23a, 23b, and 23c, and the liquid branch pipes 25a, 25b, and 25c. Is provided.
The solenoid valve kits 14a, 14b, and 14c are divided into a high-pressure gas branch pipes 26a, 26b, and 26c branched from the high-pressure gas pipe 20 and connected to one end side of the indoor heat exchangers 23a, 23b, and 23c, and a low-pressure gas pipe. And low-pressure gas branch pipes 27a, 27b, 27c connected to one end side of the indoor heat exchangers 23a, 23b, 23c.
Specifically, the high-pressure gas branch pipes 26a, 26b, and 26c and the low-pressure gas branch pipes 27a, 27b, and 27c merge at the end on the indoor unit 12a, 12b, and 12c side to form a single pipe, thereby exchanging indoor heat. Connected to the other end of each of the devices 23a, 23b, 23c.
The solenoid valve kits 14a, 14b, and 14c include balance pipes 28a, 28b, and 28c that connect the high-pressure gas branch pipes 26a, 26b, and 26c and the low-pressure gas branch pipes 27a, 27b, and 27c.
The solenoid valve kits 14a, 14b, 14c and the indoor units 12a, 12b, 12c are connected via a refrigerant pipe.
Further, in the solenoid valve kits 14a, 14b, and 14c, the solenoid valve kit 14a is closest to the outdoor unit 11, and the solenoid valve kit 14c is farthest from the outdoor unit 11.

The high-pressure gas branch pipes 26a, 26b, and 26c include high-pressure gas pipe open / close valves 29a, 29b, and 29c that open and close the flow paths of the high-pressure gas branch pipes 26a, 26b, and 26c.
The low-pressure gas branch pipes 27a, 27b, and 27c include low-pressure gas pipe opening / closing valves 30a, 30b, and 30c that open and close the flow paths of the low-pressure gas branch pipes 27a, 27b, and 27c.
The balance tubes 28a, 28b, 28c include balance tube open / close valves 31a, 31b, 31c that open and close the flow paths of the balance tubes 28a, 28b, 28c.
The solenoid valve kits 14a, 14b, and 14c include box-shaped casings 32a, 32b, and 32c.

In the solenoid valve kits 14a, 14b, 14c, liquid branch pipes 25a, 25b, 25c, high pressure gas branch pipes 26a, 26b, 26c, low pressure gas branch pipes 27a, 27b, 27c, balance pipes 28a, 28b, 28c, high pressure gas pipes. The on-off valves 29a, 29b, 29c, the low-pressure gas pipe on-off valves 30a, 30b, 30c, and the balance pipe on-off valves 31a, 31b, 31c are housed in the casings 32a, 32b, 32c, respectively.
By using the electromagnetic valve kits 14a, 14b, and 14c in which the piping and valves are combined in this way, the inter-unit piping 13 and the indoor units 12a, 12b, and 12c can be easily connected.
The operations of the high pressure gas pipe on / off valves 29a, 29b, 29c, the low pressure gas pipe on / off valves 30a, 30b, 30c, and the balance pipe on / off valves 31a, 31b, 31c are controlled by a control unit (not shown) of the outdoor unit 11. The

The air conditioner 10 includes an indoor unit 12a, 12b, and 12c, the end portion 33 of the high-pressure gas pipe 20 connected to the indoor unit 12c farthest from the outdoor unit 11, the refrigerant branching portion 22a of the liquid pipe 22, and the outdoor unit 11. And a bypass pipe 35 connecting the liquid pipe merging portion 34 that merges with the liquid pipe 22. In other words, the bypass pipe 35 connects the downstream end of the high-pressure gas pipe 20 and the upstream end of the liquid pipe 22 further upstream than the most upstream refrigerant branch portion 22a.
Here, the refrigerant branching portion 22 a is a refrigerant branching portion that branches to the indoor unit 12 a closest to the outdoor unit 11. The terminal portion 33 of the high pressure gas pipe 20 is also a connection portion between the high pressure gas pipe 20 and the high pressure gas branch pipe 26c. That is, the bypass pipe 35 joins the high-pressure gas pipe 20 on the side of the indoor unit 12c farthest to the outdoor unit 11 to the liquid pipe of the liquid pipe 22 on the upstream side of the refrigerant branching portion 22a of the indoor unit 12a closest to the outdoor unit 11. Connected to the unit 34. The end portion 33 to which the bypass pipe 35 is connected is not limited to the connection portion between the high pressure gas pipe 20 and the high pressure gas branch pipe 26c, and the indoor unit 12c is more on the high pressure gas pipe 20 than the indoor unit 12b. It is preferable to be provided at a position close to.
Since the refrigerant in the high-pressure gas pipe 20 has a higher pressure than the refrigerant in the liquid pipe 22, the refrigerant flows from the terminal end portion 33 through the bypass pipe 35 and joins the liquid pipe 22 at the liquid pipe joining portion 34 due to this pressure difference.
The bypass pipe 35 includes a flow rate adjusting unit 36 that adjusts the flow rate of the refrigerant in the bypass pipe 35. Here, the flow rate adjusting means 36 is an expansion valve whose opening degree is controlled by the control unit of the outdoor unit 11.

Here, the operation during the cooling operation will be described with reference to FIG.
During the cooling operation, the switching valve 16 is opened, the switching valve 17 is closed, the low pressure gas pipe on / off valves 30a, 30b, 30c are opened, the high pressure gas pipe on / off valves 29a, 29b, 29c are closed, and the balance pipe on / off valve is closed. 31a, 31b and 31c are opened. Thus, during the cooling operation, the refrigerant flows in the direction of the solid line arrow.
Specifically, the high-temperature and high-pressure gas refrigerant discharged from the compressor 15 flows into the outdoor heat exchanger 18 through the switching valve 16. The high-pressure liquid refrigerant that has radiated heat to the outside air and condensed in the outdoor heat exchanger 18 passes through the outdoor expansion valve 19 and flows to the liquid pipe 22. At this time, the outdoor expansion valve 19 is controlled such that the degree of supercooling of the refrigerant at the outlet of the outdoor heat exchanger 18 becomes a predetermined value.

  The refrigerant that has flowed into the liquid pipe 22 flows into the liquid branch pipes 25a, 25b, and 25c, passes through the indoor expansion valves 24a, 24b, and 24c, becomes a low-temperature and low-pressure gas-liquid two-phase state, and the indoor heat exchangers 23a, 23b, The room is cooled by evaporating at 23c. The refrigerant that has become a low pressure gas state in the indoor heat exchangers 23a, 23b, and 23c flows into the low pressure gas pipe 21 through the low pressure gas branch pipes 27a, 27b, and 27c, and is sucked into the compressor 15.

Further, during the cooling operation, part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 15 also flows in the direction of the broken arrow in FIG.
Specifically, a part of the refrigerant discharged from the compressor 15 flows into the high-pressure gas pipe 20. During the cooling operation, the high-pressure gas pipe opening / closing valves 29a, 29b, and 29c are closed, so that the refrigerant does not flow to the indoor units 12a, 12b, and 12c but flows through the high-pressure gas pipe 20 and bypasses from the end portion 33. It flows into the pipe 35, passes through the flow rate adjusting means 36, joins the liquid pipe 22 at the liquid pipe joining section 34, and then flows to the indoor units 12a, 12b, 12c. At this time, the flow rate adjusting means 36 is controlled to a predetermined opening degree so that the degree of supercooling of the refrigerant in the liquid pipe 22 after the refrigerant in the bypass pipe 35 joins does not become too small.

Thus, since the refrigerant in the high-pressure gas pipe 20 is returned to the liquid pipe 22 through the bypass pipe 35 during the cooling operation, it is possible to prevent the refrigerant from accumulating in the high-pressure gas pipe 20 that is not used during the cooling operation. It can prevent becoming a state.
Further, the bypass pipe 35 is connected to the terminal part 33 of the high-pressure gas pipe 20 and the liquid pipe merging part 34 of the liquid pipe 22 outside the electromagnetic valve kits 14a, 14b, 14c, so that the indoor units 12a, 12b, 12c Those with appropriate characteristics can be used according to the number of installed units. For this reason, it is possible to prevent the amount of the refrigerant returning from the bypass pipe 35 to the liquid pipe 22 from being excessive, and to reduce a reduction in the degree of supercooling of the refrigerant, thereby suppressing a reduction in cooling capacity. For example, when the bypass unit is provided for each indoor unit as in the above-described conventional technology, the number of bypass units increases as the number of indoor units increases, so that the amount of refrigerant returning to the liquid pipe becomes excessive.

  Further, the refrigerant that returns to the liquid pipe 22 through the bypass pipe 35 returns to the liquid pipe junction 34 on the upstream side of the liquid pipe 22 with respect to the refrigerant branching section 22a of the indoor unit 12a closest to the outdoor unit 11, so that the bypass pipe The influence on the degree of supercooling by the refrigerant returning from the liquid pipe 22 to the liquid pipe 22 is the same for each indoor unit 12a, 12b, 12c. That is, since the temperature difference of the refrigerant supplied from the liquid branch pipes 25a, 25b, and 25c to the indoor units 12a, 12b, and 12c can be reduced between the indoor units 12a, 12b, and 12c, the indoor units 12a, 12b, and 12c are cooled. Capability variation can be reduced. On the other hand, when the bypass unit is provided for each indoor unit as in the above-described conventional technology, the amount of refrigerant flowing through the bypass unit increases as the indoor unit is closer to the outdoor unit. Are likely to vary.

  Further, when the amount of refrigerant accumulated in the high-pressure gas pipe 20 is small, such as immediately after the start of the air conditioner 10, immediately after the oil recovery operation of the compressor 15 is performed, and when the heating operation is performed immediately before, the flow rate The adjusting means 36 is controlled to be fully closed. Thereby, when bypassing the refrigerant by the bypass pipe 35 is unnecessary, the bypass is not performed, and the cooling capacity can be improved by efficiently flowing the refrigerant through the outdoor heat exchanger 18.

FIG. 2 is a refrigerant circuit diagram of the air-conditioning apparatus 10 during heating operation.
During the heating operation, the switching valve 16 is closed, the switching valve 17 is opened, the low pressure gas pipe on / off valves 30a, 30b, 30c are closed, the high pressure gas pipe on / off valves 29a, 29b, 29c are opened, and the balance pipe on / off valve is opened. 31a, 31b, 31c are closed. Thus, during the heating operation, the refrigerant flows in the direction of the solid line arrow.

  Specifically, the high-temperature and high-pressure gas refrigerant discharged from the compressor 15 flows to the high-pressure gas pipe 20, and then flows to the indoor heat exchangers 23a, 23b, and 23c through the high-pressure gas branch pipes 26a, 26b, and 26c. The refrigerant is condensed in the indoor heat exchangers 23a, 23b, and 23c, thereby heating the room and passing through the indoor expansion valves 24a, 24b, and 24c to become high-pressure liquid refrigerant. At this time, the indoor expansion valves 24a, 24b, and 24c are controlled so that the refrigerant subcooling degree at the outlets of the indoor heat exchangers 23a, 23b, and 23c becomes a predetermined value. Thereafter, the refrigerant flows from the liquid branch pipes 25a, 25b, and 25c through the liquid pipe 22 to the outdoor unit 11, enters a low-temperature low-pressure gas-liquid two-phase state by the outdoor expansion valve 19, and then the outdoor heat exchanger 18 Then, the heat is absorbed to enter a low-pressure gas state, and is sucked into the compressor 15 through the switching valve 17.

In addition, during the heating operation, when the flow rate adjusting means 36 is open, a part of the refrigerant in the high-pressure gas pipe 20 passes through the bypass pipe 35 from the end portion 33 and passes through the bypass pipe 35 as shown by the broken line arrow in FIG. It flows to the pipe joining part 34 and joins the liquid pipe 22.
Specifically, when the required capacity of the indoor units 12a, 12b, and 12c exceeds a predetermined value due to the influence of room temperature or the like, the control unit of the outdoor unit 11 fully closes the flow rate adjusting unit 36, and refrigerant is supplied to the bypass pipe 35. Do not flow. Thereby, the fall of the heating capability by a refrigerant | coolant bypassing indoor heat exchanger 23a, 23b, 23c by the bypass pipe 35 can be prevented.

  When the required capacity of the indoor units 12a, 12b, and 12c is less than a predetermined value, the control unit of the outdoor unit 11 opens the flow rate adjusting means 36, and the heating capacity of the indoor units 12a, 12b, and 12c exceeds the required capacity. The opening degree of the flow rate adjusting means 36 is controlled so as not to become. Thereby, for example, while the compressor 15 is operated at the lowest frequency, the demand of the indoor units 12a, 12b, and 12c is higher than the heating capacity when the blowers of the indoor heat exchangers 23a, 23b, and 23c are operated at the minimum rotation speed. When the capacity is small, it is possible to prevent excessive heating by opening the flow rate adjusting means 36 and bypassing the refrigerant to the bypass pipe 35.

FIG. 3 is a refrigerant circuit diagram of the air conditioner 10 during mixed operation of cooling and heating.
FIG. 3 shows a state in which the two indoor units 12a and 12c are in the cooling operation and the indoor unit 12b is in the heating operation. In this case, the outdoor heat exchanger 18 is used as a condenser.
In the mixed operation in FIG. 3, the switching valve 16 is opened, the switching valve 17 is closed, the low pressure gas pipe on / off valves 30a and 30c are opened, the low pressure gas pipe on / off valve 30b is closed, and the high pressure gas pipe on / off valve 29a. 29c are closed, the high-pressure gas pipe on / off valve 29b is opened, the balance pipe on / off valves 31a and 31c are opened, and the balance pipe on / off valve 31b is closed. As a result, during mixed operation, the refrigerant flows in the direction of the solid arrow.

Specifically, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 15 branches to the outdoor heat exchanger 18 for cooling, and the other part branches to the high-pressure gas pipe 20 for heating. Flowing.
The cooling refrigerant flows into the outdoor heat exchanger 18 through the switching valve 16. The high-pressure liquid refrigerant that has radiated heat to the outside air and condensed in the outdoor heat exchanger 18 passes through the outdoor expansion valve 19 and flows to the liquid pipe 22. At this time, the outdoor expansion valve 19 is controlled such that the degree of supercooling of the refrigerant at the outlet of the outdoor heat exchanger 18 becomes a predetermined value.
The refrigerant that has flowed into the liquid pipe 22 flows into the liquid branch pipes 25a and 25c, passes through the indoor expansion valves 24a and 24c, becomes a low-temperature and low-pressure gas-liquid two-phase state, and evaporates in the indoor heat exchangers 23a and 23c. Cool the room. The refrigerant that has become a low-pressure gas state in the indoor heat exchangers 23 a and 23 c flows into the low-pressure gas pipe 21 through the low-pressure gas branch pipes 27 a and 27 c and is sucked into the compressor 15.

  Further, the heating refrigerant flows into the high-pressure gas pipe 20, and then flows through the high-pressure gas branch pipe 26b to the indoor heat exchanger 23b. The refrigerant is condensed in the indoor heat exchanger 23b, thereby heating the room and passing through the indoor expansion valve 24b to become a high-pressure liquid refrigerant. At this time, the indoor expansion valve 24b is controlled so that the degree of supercooling of the refrigerant at the outlet of the indoor heat exchanger 23b becomes a predetermined value. Thereafter, the refrigerant joins the liquid pipe 22 through the liquid branch pipe 25b.

  Further, during mixed operation, when the flow rate adjusting means 36 is open, a part of the refrigerant in the high-pressure gas pipe 20 passes through the bypass pipe 35 from the end portion 33 as shown by the broken arrow in FIG. It flows to the pipe joining part 34 and joins the liquid pipe 22. During the mixed operation, the flow rate adjusting means 36 may be fully closed.

  As described above, according to the first embodiment to which the present invention is applied, the air conditioner 10 includes the outdoor unit 11 and the plurality of indoor units 12a, 12b, and 12c, and includes a plurality of indoor units. The units 12a, 12b, and 12c can be operated either by cooling or heating, and the plurality of indoor units 12a, 12b, and 12c can be operated by mixing cooling and heating. The units 12a, 12b, and 12c are connected by a high-pressure gas pipe 20, a low-pressure gas pipe 21, and a liquid pipe 22, and the refrigerant branch portion 22a to the indoor unit 12a closest to the outdoor unit 11 in the liquid pipe 22 and the outdoor unit 11 are connected. The liquid pipe merging portion 34 is provided between the terminal portion 33 of the high pressure gas pipe 20 connected to the indoor unit 12c farthest from the outdoor unit 11 and the liquid pipe merging portion. It comprises a bypass pipe 35 that connects the 34. Thereby, during the cooling operation, the refrigerant accumulated in the high-pressure gas pipe 20 can be returned to the liquid pipe 22 through the bypass pipe 35, so that the gas shortage can be prevented and the end portion 33 of the high-pressure gas pipe 20 and the liquid pipe joining portion can be prevented. 34, an appropriate amount of refrigerant can be returned to the liquid pipe 22 regardless of the number of indoor units 12a, 12b, and 12c installed, thereby reducing a decrease in the degree of supercooling of the refrigerant. A decrease in cooling capacity can be suppressed. In addition, since the refrigerant returns from the terminal portion 33 of the high-pressure gas pipe 20 to the liquid pipe merging portion 34 of the liquid pipe 22 on the indoor unit 12a side closest to the outdoor unit 11, a plurality of indoor units installed from the liquid pipe 22 are installed. The temperature difference of the refrigerant flowing to 12a, 12b, 12c can be reduced. For this reason, variation in the cooling capacity of each indoor unit 12a, 12b, 12c can be reduced.

  Further, since the flow rate adjusting means 36 for adjusting the flow rate of the refrigerant in the bypass pipe 35 is provided, the flow rate adjusting means 36 can appropriately set the flow rate of the refrigerant in the bypass pipe 35 and reduce the decrease in the degree of supercooling of the refrigerant in the liquid pipe 22. As a result, a decrease in cooling capacity can be suppressed.

[Second Embodiment]
Hereinafter, a second embodiment to which the present invention is applied will be described with reference to FIG. In the second embodiment, parts that are configured in the same manner as in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.
In the first embodiment, the electromagnetic valve kits 14a, 14b, and 14c are individually connected to the indoor units 12a, 12b, and 12c. However, the second embodiment is used for each indoor unit. This is different from the first embodiment in that a collective electromagnetic valve kit 114 in which a plurality of electromagnetic valve kits are integrated is used.

FIG. 4 is a refrigerant circuit diagram of the air-conditioning apparatus 110 according to the second embodiment.
The air conditioner 110 includes an outdoor unit 11, indoor units 12a, 12b, and 12c, an inter-unit pipe 113, and a collective solenoid valve kit 114.
The inter-unit pipe 113 includes a high-pressure gas pipe 20, a low-pressure gas pipe 21, and a liquid pipe 22.

Specifically, the high pressure gas pipe 20 includes a high pressure gas pipe 120 that connects the outdoor unit 11 and the collective solenoid valve kit 114, and an in-kit high pressure gas pipe 120 k provided in the collective solenoid valve kit 114.
The low pressure gas pipe 21 includes a low pressure gas pipe 121 that connects the outdoor unit 11 and the collective solenoid valve kit 114, and an in-kit low pressure gas pipe 121 k provided in the collective solenoid valve kit 114.
The liquid pipe 22 includes a liquid pipe 122 that connects the outdoor unit 11 and the collective solenoid valve kit 114, and an in-kit liquid pipe 122 k provided in the collective solenoid valve kit 114.

The collective solenoid valve kit 114 includes a high-pressure gas pipe 120k in the kit, a low-pressure gas pipe 121k in the kit, and a liquid pipe 122k in the kit. The in-kit high-pressure gas pipe 120k, the in-kit low-pressure gas pipe 121k, and the in-kit liquid pipe 122k linearly extend substantially parallel to each other.
The collective solenoid valve kit 114 is branched from the refrigerant branch portions 22a, 22b, 22c of the liquid pipe 122k in the kit and is connected to one end side of the indoor heat exchangers 23a, 23b, 23c. 25c.
Furthermore, the collective solenoid valve kit 114 includes a high-pressure gas branch pipes 26a, 26b, 26c branched from the high-pressure gas pipe 120k in the kit and connected to one end side of the indoor heat exchangers 23a, 23b, 23c, and a low-pressure gas in the kit. Low pressure gas branch pipes 27a, 27b, 27c branched from the pipe 121k and connected to one end side of the indoor heat exchangers 23a, 23b, 23c, and balance pipes 28a, 28b, 28c are provided.
The collective solenoid valve kit 114 and the indoor units 12a, 12b, and 12c are connected via a refrigerant pipe.

  The collective solenoid valve kit 114 includes a box-shaped housing 132. In-kit high-pressure gas pipe 120k, in-kit low-pressure gas pipe 121k, in-kit liquid pipe 122k, liquid branch pipes 25a, 25b, 25c, high-pressure gas branch pipes 26a, 26b, 26c, low-pressure gas branch pipes 27a, 27b, 27c, balance The pipes 28a, 28b, 28c, the high pressure gas pipe on / off valves 29a, 29b, 29c, the low pressure gas pipe on / off valves 30a, 30b, 30c, and the balance pipe on / off valves 31a, 31b, 31c are housed in a housing 132. It is integrated.

One end of the low-pressure gas pipe 121k in the kit is connected to the low-pressure gas pipe 121 on one end side of the casing 132, and the other end of the low-pressure gas pipe 121k in the kit is closed on the other end side of the casing 132.
One end of the in-kit liquid tube 122k is connected to the liquid tube 122 on one end side of the housing 132, and the other end of the in-kit liquid tube 122k is closed on the other end side of the housing 132.
One end of the high-pressure gas pipe 120 k in the kit is connected to the high-pressure gas pipe 120 on one end side of the housing 132, and the other end of the high-pressure gas pipe 120 k in the kit is a bypass pipe at the terminal portion 133 on the other end side of the housing 132. 35 is connected to one end. The other end of the bypass pipe 35 is connected to the liquid pipe junction 34 provided in the liquid pipe 122. The liquid pipe merging portion 34 is provided on the upstream side of the refrigerant branching portion 22 a in the liquid pipe 22 and is disposed in the vicinity of the connection portion 122 </ b> L between the in-kit liquid pipe 122 k and the liquid pipe 122.

  In the second embodiment, the solenoid valve kit is configured compactly as a collective solenoid valve kit 114, and is located on one end side of the collective solenoid valve kit 114 and a terminal portion 133 located on the other end side of the collective solenoid valve kit 114. Since the bypass pipe 35 is connected to the liquid pipe junction 34 to be performed, the bypass pipe 35 can be shortened. For this reason, the connection of the bypass pipe 35 becomes easy and the workability is improved. In addition, since the end portion 133 and the liquid pipe merging portion 34 are located on the other end side and one end side of the collective solenoid valve kit 114 and are easily distinguishable, the workability of the bypass pipe 35 is good.

  As described above, according to the second embodiment to which the present invention is applied, the indoor heat exchangers 23a, 23b, 23c of the indoor units 12a, 12b, 12c, the high pressure gas pipe 20, the low pressure gas pipe 21, and , High-pressure gas branch pipes 26a, 26b, 26c, low-pressure gas branch pipes 27a, 27b, 27c and liquid branch pipes 25a, 25b, 25c, and high-pressure gas branch pipes 26a, 26b, 26c. And high pressure gas pipe on / off valves 29a, 29b, 29c, low pressure gas pipe on / off valves 30a, 30b, 30c, and balance pipe on / off for controlling the flow direction of refrigerant in the low pressure gas branch pipes 27a, 27b, 27c (switching the flow). Valves 31a, 31b, 31c, high-pressure gas branch pipes 26a, 26b, 26c, low-pressure gas branch pipes 27a, 27b, 27c, liquid branch pipes 25a, 25b, 2 c, high-pressure gas pipe opening / closing valves 29a, 29b, 29c, low-pressure gas pipe opening / closing valves 30a, 30b, 30c, and a housing 132 for storing balance pipe opening / closing valves 31a, 31b, 31c, and these refrigerant pipes, The on-off valve and housing 132 is provided as a collective electromagnetic valve kit 114 in which the refrigerant pipes and on-off valves of the plurality of indoor units 12a, 12b, and 12c are integrally provided in the housing 132, and one end of the bypass pipe 35 is The other end of the collective solenoid valve kit 114 is connected to the terminal portion 133 of the high-pressure gas pipe 20, and the other end of the bypass pipe 35 is between the liquid pipe 22 at one end of the collective solenoid valve kit 114 and the outdoor unit 11. Connected to. By using the collective solenoid valve kit 114, the distance between the terminal portion 133 of the high-pressure gas pipe 20 and the liquid pipe merging section 34 can be reduced, so that the connection of the bypass pipe 35 is facilitated and the workability is improved. In addition, the compact collective solenoid valve kit 114 makes it easy to confirm the positions of the terminal portion 133 and the liquid pipe merging portion 34 of the high-pressure gas pipe 20, thereby improving the workability. One end of the bypass pipe 35 is provided at the other end of the collective solenoid valve kit 114, but this position is not limited to the end face in the longitudinal direction of the collective solenoid valve kit 114 as long as it is the other end. May be.

In addition, the said embodiment shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said embodiment.
In the first and second embodiments, the flow rate adjusting means 36 has been described as an expansion valve, but the present invention is not limited to this. For example, the flow rate adjusting means 36 may be constituted by a capillary tube to depressurize the refrigerant.

10,110 Air conditioner 11 Outdoor unit 12a Indoor unit (indoor unit closest to outdoor unit)
12b Indoor unit 12c Indoor unit (indoor unit farthest from outdoor unit)
20 High-pressure gas pipe 21 Low-pressure gas pipe 22 Liquid pipe 22a Refrigerant branch part 25a, 25b, 25c Liquid branch pipe (refrigerant pipe)
26a, 26b, 26c High-pressure gas branch pipe (refrigerant pipe)
27a, 27b, 27c Low-pressure gas branch pipe (refrigerant pipe)
29a, 29b, 29c High pressure gas pipe open / close valve (open / close valve)
30a, 30b, 30c Low pressure gas pipe open / close valve (open / close valve)
33, 133 Terminal part 34 Liquid pipe confluence part 35 Bypass pipe 36 Flow rate adjusting means 114 Collective solenoid valve kit 132 Case

Claims (3)

Having an outdoor unit and a plurality of indoor units, the plurality of indoor units can be operated either by cooling or heating, and the plurality of indoor units are operated by mixing cooling and heating. In possible air conditioning equipment,
The outdoor unit and the indoor unit are connected by a high pressure gas pipe, a low pressure gas pipe, and a liquid pipe,
A liquid pipe merging portion is provided between the refrigerant branching portion to the indoor unit closest to the outdoor unit in the liquid pipe and the outdoor unit;
An air conditioner comprising a bypass pipe connecting a terminal portion of the high-pressure gas pipe connected to the indoor unit farthest from the outdoor unit and the liquid pipe junction.   The air conditioner according to claim 1, further comprising a flow rate adjusting unit that adjusts a flow rate of the refrigerant in the bypass pipe. A refrigerant pipe connecting the indoor heat exchanger of the indoor unit to the high-pressure gas pipe, the low-pressure gas pipe, and the liquid pipe; an on-off valve that switches a flow of refrigerant in the refrigerant pipe according to an operating state; and the refrigerant pipe And a housing for housing the on-off valve,
The refrigerant pipe, the on-off valve, and the housing are provided as a collective electromagnetic valve kit in which the refrigerant pipe and the on-off valve of the plurality of indoor units are integrally provided in the housing,
One end of the bypass pipe is connected to the terminal portion of the high-pressure gas pipe of the collective solenoid valve kit, and the other end of the bypass pipe is between the liquid pipe and the outdoor unit of the collective solenoid valve kit. The air conditioner according to claim 1, wherein the air conditioner is connected.

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