JPH086980B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a multi-room air conditioner in which a plurality of indoor units are connected to an outdoor unit, and in particular, air conditioning is selected for each indoor unit. The present invention relates to an air conditioner that can be performed simultaneously or simultaneously.

[Conventional technology]

Conventionally, as an air conditioner of this type, for example,
Some are published in the 47-22558 publication.

FIG. 7 is an overall configuration diagram centering on the refrigerant system of the conventional air conditioner disclosed in the above publication.

In the figure, (1) is the outdoor unit of the air conditioner,
(2) is a compressor, (3) is a four-way valve, (4) is an outdoor heat exchanger, (5) is a check valve, (6) is an expansion valve, (7) is a receiver, and (8) is an accumulator. Then, these constitute the outdoor unit (1). Further, (9a) to (9c) are indoor units connected to the outdoor unit (1), (10) is an indoor heat exchanger, (11) is a check valve, and (12) is an expansion valve. These constitute the indoor units (9a) to (9c). And, (13) and (14) are first and second connection pipes for connecting the indoor units (9a) to (9c) and the outdoor unit (1). The solid arrows indicate the refrigerant flow in the heating operation, and the dashed arrows indicate the refrigerant flow in the cooling operation.

The conventional air conditioner configured as described above operates as follows.

First, in the heating operation state, the high-temperature high-pressure refrigerant gas discharged from the compressor (2) flows into the indoor units (9a) to (9c) through the first connecting pipe (13) and the indoor heat exchanger (10 ) Heat-exchanges with indoor air (heating) and condenses into liquid. Refrigerant liquid liquefied in each indoor unit (9a)-(9c), check valve (11)
Through the second connection pipe (14), and then through the liquid receiver (7) into the expansion valve (6), where it is decompressed to a low-temperature gas-liquid two-phase state and the outdoor heat It flows into the exchanger (4). The refrigerant flowing into the outdoor heat exchanger (4) evaporates by exchanging heat with the outside air, becomes a gas state, and is again sucked into the compressor (2) to form a circulation cycle.

On the other hand, in the cooling operation state, the circulation cycle is the opposite of the heating operation. That is, the refrigerant that has become high-temperature high-pressure gas in the compressor (2) is heat-exchanged (cooled) by the outside air in the outdoor heat exchanger (4), condensed and liquefied, and connected through the liquid receiver (7). Flows from the pipe (14) into the guide machines (9a) to (9c). The refrigerant liquid that has flowed into each of the indoor units (9a) to (9c) is decompressed by the expansion valve (12) to a low-temperature gas-liquid two-phase state, and is heated by the indoor heat exchanger (10) with the indoor air and heat. Exchange (cooling)
The gas is turned into a gas state, merges in the connecting pipe (13), and is sucked into the compressor (2) again.

[Problems to be Solved by the Invention]

Since the conventional multi-room type air conditioner is configured as described above, all the indoor units (9a) to (9c) need to perform heating operation or cooling operation, so a place where cooling is required There is a possibility that heating will be performed in the area, and that cooling will be performed where heating is required.

In particular, when this kind of multi-room air conditioner is installed in a large-scale building, the air-conditioning load is remarkably different between the interior section and perimeter section, or the office room such as the general office and computer room. In this way, the situation is predicted. Also, in the case of a tenant building, etc.,
Since the heat load changes each time the user changes,
It is impossible to divide everything into a cooling zone and a heating zone. In order to cope with this, it is not practical to install two units, a cooling indoor unit and a heating indoor unit, in the same room because of high equipment cost.

Therefore, the present invention is an air conditioner that can selectively or simultaneously perform cooling / heating operation for each indoor unit in response to a cooling / heating requirement of a space in which the indoor unit is installed, even if a plurality of indoor units are connected to the outdoor unit. The purpose is to provide.

[Means for solving the problem]

In the air conditioner of the present invention, one of the plurality of indoor units is switchably connected to the first or second connection pipe connecting to the outdoor unit, and the first heat exchanger is connected to the outdoor heat exchanger of the outdoor unit. A gas-liquid separator in the middle of the connection pipe, a third connection pipe connecting the other of the plurality of indoor units and the gas-liquid separator via a flow controller, the gas-liquid separator and the second Of the indoor switch of the above plurality of indoor units, and the bypass pipe connecting the connecting pipes of the above, a pipe switch and a heat exchange section for exchanging heat with the third connecting pipe And a controller for controlling the opening and closing of the pipeline switch.

Further, in the air conditioner in which the first control controller is provided in the indoor unit, the third connection pipe connects the other first flow rate controller of the plurality of indoor units to the gas-liquid separator. , A second flow rate controller is disposed in the middle of the second flow rate controller depending on the operation mode of each indoor unit and the refrigerant state of the connecting pipe between the first and second flow rate controllers. The opening degree is adjusted and the opening / closing of the pipeline switch is controlled.

[Action]

In the case of the cooling main operation in the cooling / heating simultaneous operation, or in the case of only the cooling operation, the conduit switch is opened, the liquid refrigerant is supplied to the bypass pipe to cause the heat exchange part to function, and the cooling operation is performed from the third connection pipe. The refrigerant supplied to the indoor unit in the state is cooled. In the case of heating-main operation or heating operation in simultaneous cooling and heating operation, by closing the road switch,
Prevent the hot gas refrigerant from bypassing the indoor unit via the bypass pipe.

In the case of mainly heating in the cooling / heating simultaneous operation, the refrigerant state of the third connection pipe from the first flow rate controller to the second flow rate controller is input to the controller, and the input refrigerant state is predetermined. The opening degree of the second flow rate controller is adjusted so that the value is within the range. Furthermore, in the case of mainly heating, the pipe line switch is controlled to be fully closed.

In the case of simultaneous cooling and heating operation mainly by cooling, the refrigerant state of the third connection pipe from the first flow rate controller to the second flow rate controller is input to the controller, and the input refrigerant state is predetermined. The opening degree of the second flow rate controller is adjusted so that the value is within the range. Furthermore, in the case of mainly cooling, the line switch is controlled to be fully opened.

In the case of only the heating operation, the controller controls so that the second flow rate controller is fully opened and the pipeline switch is fully closed.

In the case of only the cooling operation, the controller controls the second flow rate controller to be fully opened and the pipeline switch to be fully opened.

〔Example〕

 Examples of the present invention will be described below.

FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to an embodiment of the present invention. Further, FIGS. 2 to 4 show the operation state of FIG. 1 during the cooling and heating operation in the embodiment, and FIG. 2 is a refrigerant circulation diagram showing the operation operation state of only cooling or heating, and FIG. Fig. 4 and Fig. 4 show the operation of the cooling and heating simultaneous operation, respectively. Fig. 3 is mainly for heating (when the heating operation capacity is larger than the cooling operation capacity), and Fig. 4 is for cooling mainly (the cooling operation capacity is the heating operation capacity). It is a refrigerant circulation diagram showing a driving operation state of (when larger than).

FIG. 5 is a flowchart showing the control flow of the controller. FIG. 6 is an overall configuration diagram centering on the refrigerant system of the air conditioner of another embodiment of the present invention. In the figure, the same reference numerals and symbols as those of the conventional example indicate the same or corresponding portions as those of the conventional example, and therefore, duplicated description will be omitted here.

Also in this embodiment, similar to the conventional example, a case where one outdoor unit and three indoor units are connected will be described, but basically the same applies when four or more indoor units are connected. The outdoor unit (1) of the air conditioner is composed of a compressor (2), a four-way valve (3), an outdoor heat exchanger (4), an accumulator (8) and the like.

In the figure, (19) is a gas-liquid separator provided in the middle of the first connection pipe (13) connected to the outdoor heat exchanger (4) and has a function of separating the refrigerant into a gas and a liquid. (2
0) is one of the indoor heat exchanger (10) and the first connecting pipe (1
A three-way switching valve that is switchably connected to 3) and the second connection pipe (14), and (21) is a first flow rate controller that is connected to the other of the indoor heat exchanger (10) Type expansion valve.
The three-way switching valve (20), the indoor heat exchanger (10), and the first
The indoor units (9a) to (9c) are configured by the electric expansion valve (21). Further, (22) connects the first electric expansion valve (21) side of each indoor unit (9a) to (9c) and the lower part of the gas-liquid separator (19) of the first connecting pipe (13). Third connecting pipe to
(23) is an electric expansion valve that is a second flow rate controller provided in the third connection pipe (22). (24) is a solenoid valve that functions as a line switch, (25) is a capillary tube that functions as a third flow rate controller, (26) is a gas-liquid separator (19) of the third connecting pipe (22). A heat exchange section for exchanging heat with the second electric expansion valve (23), in this case a double pipe heat exchanger, (2
Reference numeral 7) is a bypass pipe that branches from a substantially central portion in the height direction of the gas-liquid separator (19) and is connected to the second connection pipe (14). In the middle of this bypass pipe (27), the solenoid valve (2
4), a capillary tube (25) and a heat exchange section (26) are provided.

(30a) ~ (30c) are each indoor unit (9a) ~ (9c)
Is an indoor unit operation controller that outputs the operation mode signal of 1. to the controller (33). Further, (31) and (32) are composed of a thermistor or the like provided in the pipe of the third connecting pipe (22) from the first electric expansion valve (21) to the second electric expansion valve (23). A pressure sensor such as a temperature sensor and an electric pressure transducer. The controller (33) includes indoor unit operation controllers (30a) to (3
0c), a signal from the temperature sensor (31) and a signal from the pressure sensor (32) are input, a signal for adjusting the valve opening is output to the second electric expansion valve (23), and the electromagnetic valve (24) outputs the signal. It outputs a signal that instructs opening and closing.

Further, X _{V2 in} FIG. 5 is the current opening command value of the second electric expansion valve (23), X _V2 ^* is the new opening command value, and Δ _V2
X _V2 shows this amount of change. SC is the third connecting pipe (2
2) shows the degree of refrigerant supercooling in the part where the temperature sensor (31) and pressure sensor (32) are provided, SC _H is the upper limit value of this control target supercooling degree, and SC _L is the lower limit value.

The operation of the air conditioner of the embodiment of the present invention thus configured will be described.

First, the case of only the heating operation will be described with reference to FIG.

The high-temperature high-pressure refrigerant gas discharged from the compressor (2) is guided from the outdoor to the indoor side by the second connecting pipe (14), and the three-way switching valve (20) of each indoor unit (9a) to (9c). ), Flows into the indoor heat exchanger (10), and the heat-exchanged (heating) refrigerant is condensed and liquefied. At this time, each indoor unit (9a) ~ (9c)
The flow rate of the refrigerant flowing in is controlled by the first electric expansion valve (21) so that the refrigerant state at the outlet of the indoor heat exchanger (10) becomes a slightly supercooled liquid. The refrigerant in the liquid state is decompressed to a low pressure by the first electric expansion valve (21) and then flows into the third connecting pipe (22) and joins.

When the controller (33) takes in each indoor unit operation mode signal from the indoor unit operation controllers (30a) to (30c) and detects that all the guide units (9a) to (9c) are in heating operation,
As shown in the control flow chart of FIG. 5, in the heating operation mode, the solenoid valve (24) is fully closed and the second electric expansion valve (23) is fully opened. Therefore, the refrigerant condensed and liquefied in the indoor heat exchanger (10) becomes the second electric expansion valve (2
After passing through 3), passing through the first connecting pipe (13), it flows into the outdoor heat exchanger (4) of the outdoor unit (1), exchanges heat there, becomes a gas state, and returns to the compressor (2) again. Inhaled. In this way, the circulation cycle is configured and heating operation is performed.

Next, the case of only the cooling operation will be described with reference to FIG.

The high-temperature high-pressure refrigerant gas discharged from the compressor (2) is heat-exchanged in the outdoor heat exchanger (4) to be condensed and liquefied, and then the first
From the connecting pipe (13) of the third through the gas-liquid separator (19)
Through the second electric expansion valve (23) and then into the indoor units (9a) to (9c). At this time, the controller (33) takes in the indoor unit operation mode signal from the indoor unit operation controllers (30a) to (30c), and all indoor units (9a)
When (9c) is detected to be in the cooling operation mode which is the cooling operation, the second electric expansion valve (23) is fully opened as shown in the control flow chart of FIG.

The refrigerant flowing into each indoor unit (9a) to (9c) is decompressed to a low pressure by the first electric expansion valve (21), flows into the indoor heat exchanger (10), and exchanges heat (cools) with the indoor air. Are evaporated and gasified. Then, the refrigerant in the gas state constitutes a circulation cycle in which the refrigerant is sucked into the compressor (2) again via the three-way switching valve (20), the second connecting pipe (14),
Perform cooling operation.

At this time, the controller (33) fully opens the solenoid valve (24) as shown in the flow chart of FIG. 5, so that a part of the refrigerant liquid passing through the gas-liquid separator (19) is bypassed. It flows into the pipe (27). The refrigerant liquid that has flowed into the bypass pipe (27) is decompressed to a low pressure by the capillary pipe (25), and then heat-exchanged between the third connection pipe (22) and the heat exchange section (26) (refrigerant of the third connection pipe (22)). Is cooled) and gasified into the second connecting pipe (14). Further, the refrigerant liquid flowing into the third connecting pipe (22) is cooled by the refrigerant flowing through the bypass pipe (27) in the heat exchanging part (26) and is in a state of being slightly supercooled, resulting in the second electric expansion. Each indoor unit (9a) through valve (23)
Flow into (9c).

Next, the case of heating-main operation in simultaneous cooling and heating operation will be described with reference to FIGS. 3 and 5.

First, the refrigerant discharged from the compressor (2) flows into the heating indoor units (9b) and (9c) from the second connection pipe (14) through the three-way switching valve (20), and the indoor heat exchange is performed. Heat is exchanged (heating) in the vessel (10) to condense and liquefy the refrigerant. In this case, the flow rate of the refrigerant to each indoor unit (9b), (9c) is controlled by the first electric expansion valve (21) so that the refrigerant state at the outlet of the indoor heat exchanger (10) becomes a slightly supercooled liquid. Controlled. Then, the condensed and liquefied refrigerant is slightly reduced in pressure by the first electric expansion valve (21), becomes intermediate pressure, and flows into the third connection pipe (22). A part of the refrigerant flowing into the third connecting pipe (22) enters the cooling indoor unit (9a) and is further depressurized to a low pressure by the first electric expansion type (21), and then the indoor heat exchanger ( Ten)
The first connection pipe (13) is supplied through the three-way valve (20) after entering and exchanging heat (cooling) and evaporating to a slightly overheated gas state.
Flow into. On the other hand, the other refrigerant liquid is decompressed to a low pressure by the second electric expansion valve (23) and then the third connection pipe (22).
Flows into the first connecting pipe (13) from the cooling indoor unit (9a)
A cooling cycle is formed in which the refrigerant merges with the refrigerant from and is exchanged with the outdoor heat exchanger (4) to be in a gas state and is again sucked into the compressor (2) to perform a heating main operation.

The operation of the second electric expansion valve (21) during this operation will be described in detail with reference to FIG.

The indoor unit operation controllers (30a) to (30c) are included in the controller (33).
From the indoor unit operation mode signal and the signals of the temperature sensor (31) and the pressure sensor (32) provided in the third connecting pipe (22) are input. When it is detected from this input signal that it is in the heating main mode of simultaneous cooling and heating operation, the solenoid valve (24) is fully closed and the temperature sensor (31) and the pressure sensor (3
From the signal of 2), the supercooling degree SC of the refrigerant liquid flowing through the third connecting pipe (22) provided with these sensors is calculated. And further the SC compares whether within the control supercooling degree SC _L to SC _H, the valve opening degree to the current and the second electric expansion valve when within this range (23) The second electric expansion valve (23) with the command value X _{V2 as it} is as the new valve opening command value X _V2 ^*
Output to.

If SC is greater than the upper limit value SC _H of the controlled supercooling degree, the valve opening degree obtained by adding the valve opening change amount ΔX _V2 to the current valve opening command value X _V2, and SC is the controlled supercooling degree If the lower limit value SC _L smaller than outputs the new valve opening command value opening degree minus the [Delta] X _V2 from X _V2 X _V2 ^* as a second electric expansion valve (23). The opening of the second electric expansion valve (23) is adjusted as described above, and the refrigerant liquid in the portion where the temperature sensor (31) and the pressure sensor (32) of the third connection pipe (22) are provided. Keep the degree of supercooling within a predetermined range. The controlled supercooling degree is set to a value slightly smaller than the controlled supercooling degree of the first electric expansion valve (21) corresponding to the heating operation indoor units (9b) and (9c).

Further, the case of the cooling main operation in the cooling / heating simultaneous operation will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, the refrigerant discharged from the compressor (2) flows into the outdoor heat exchanger (4) and exchanges heat by an arbitrary amount to become a gas-liquid two-phase high-temperature high-pressure state. It flows into the gas-liquid separator (19) of the connection pipe (13). Then, after being separated into gas and liquid here, it is sent to the inside of the room. The gaseous refrigerant gas separated in the gas-liquid separator (19) is introduced into the indoor unit (9a) in the heating operation state via the three-way switching valve (20), and heat is exchanged in the indoor heat exchanger (10). It is heated (condensed) to be condensed and liquefied, and after being depressurized to an intermediate pressure by the first electric expansion valve (21), it flows into the third connection pipe (22).

At this time, the flow rate of the refrigerant flowing into the heating indoor unit (9a) is controlled so that the refrigerant state at the outlet of the indoor heat exchanger (10) becomes a liquid that is slightly supercooled. It is regulated and controlled.

On the other hand, the liquid refrigerant liquid separated by the gas-liquid separator (19) flows into the bypass pipe (27) and the third connecting pipe (22). Refrigerant liquid flowing into the bypass pipe (27) is
After depressurizing to a low pressure by 5), the third connection pipe (22) and the heat exchange section (26) exchange heat (cool the refrigerant in the third connection pipe (22)) to be gasified, and then the second connection pipe. It flows into (14). Further, the refrigerant liquid flowing into the third connecting pipe (22) is cooled by the refrigerant flowing through the bypass pipe (27) in the heat exchanging portion (25), and is in a state of being slightly supercooled. The flow rate is adjusted by the expansion valve (23), and after being reduced to an intermediate pressure, it joins the refrigerant from the heating indoor unit (9a). Then, this refrigerant liquid is depressurized from the third connection pipe (22) to each cooling indoor unit (9b), (9c) by the first electric expansion valve (21) to a low pressure state, and then the indoor heat exchanger ( 10),
Evaporate by exchanging heat (cooling).

At this time, the flow rate of the refrigerant flowing into the cooling indoor units (9b), (9c) is adjusted so that the refrigerant state at the outlet of the indoor heat exchanger (10) becomes a slightly overheated gas. It is controlled by adjusting the valve opening degree. And the air conditioner indoor unit (9b),
The refrigerant that has evaporated to gas in (9c) flows into the second connecting pipe (14) through the three-way valve (20) and is again sucked into the compressor (2) to form a circulation cycle to perform the cooling main operation. Do. The operation of the second electric expansion valve (23) during this operation will be described in detail with reference to FIG.

The indoor unit operation controllers (30a) to (30c) are included in the controller (33).
From the indoor unit operation mode signal and the signals of the temperature sensor (31) and the pressure sensor (32) provided in the third connecting pipe (22) are input. When the controller (33) detects from these input signals that the cooling / heating simultaneous operation is in the cooling main mode, the controller (33) fully opens the solenoid valve (24) and outputs signals from the temperature sensor (31) and the pressure sensor (32). From this, the degree of supercooling SC of the refrigerant liquid flowing through the third connection pipe (22) provided with these sensors is calculated. And this SC is the control target supercooling degree
SC _L to SC _H compares whether is in the range of, if it is in this range, the current second as new valve the valve opening degree command value X _V2 of the electric expansion valve (23) The opening command value X _V2 ^* is output to the second electric expansion valve (23).

If SC is greater than the upper limit value SC _H of the control target supercooling degree, the valve opening degree obtained by subtracting the valve opening change amount ΔX _V2 from the current valve opening command value X _V2, and SC is the control target supercooling degree. Lower limit of degree
SC If _L is smaller than outputs to the second electric expansion valve opening degree plus [Delta] X _V2 to X _V2 as new valve opening command X _V2 ^* (23).

As described above, the opening degree of the second electric expansion valve (23) depends on the flow rate of the refrigerant liquid in the portion of the third connecting pipe (22) where the temperature sensor (31) and the pressure sensor (32) are provided. The cooling degree is controlled so as to be kept within a predetermined range.

As described above, in the cooling main mode at the time of simultaneous cooling and heating operation of the air conditioner of this embodiment, heat exchange between the refrigerant flowing through the third connection pipe (22) and the refrigerant flowing through the bypass pipe (27) causes Third separated by gas-liquid separator (19)
The refrigerant liquid passing through the connection pipe (22) of the above is put into a supercooled state, and the second electric expansion valve (23) and the first electric expansion valve (21) The refrigerant in between is controlled to be in a supercooled state. Therefore, even if the path of the third connecting pipe (22) from the gas-liquid separator (19) to each indoor unit (9a) to (9c) becomes long and there is a pressure loss, etc. It does not become a gas-liquid two-phase state. Therefore, the refrigerant state near the inlet of the first electric expansion valve (21) of the indoor units (9b) and (9c) in the cooling operation state is irrespective of the length of the third connecting pipe (22). ， Can always be in liquid state. As a result, the flow rate controllability of the first electric expansion valve (21) is good, and efficient cooling / heating simultaneous operation can be performed. In the above embodiment, the temperature sensor (31) and the pressure sensor (3) that detect the degree of subcooling of the third connecting pipe (22).
2) is provided between the second electric expansion valve (23) and the first electric expansion valve (21), respectively, but it is not particularly limited to this, and as shown in FIG. , One for each indoor unit, and controls the valve opening of the second electric expansion valve (23) so as to maintain the supercooling degree with a small degree of supercooling within a predetermined range, Connection piping for each indoor unit (22)
The refrigerant in the vicinity of the inlet of the first electric expansion valve (21) of the indoor unit that is in the cooling operation state can always be in the liquid state regardless of the length and the height difference.

Further, in the above-described embodiment, the controller (33) outputs the indoor unit operation mode signal indicating whether the indoor unit operation controller (33a) to (33c) is heating or cooling, the temperature sensor (31), and the pressure sensor (32) to the refrigerant temperature. Although the signal and the pressure signal are configured to be input, there is no particular need for such a configuration and it is sufficient that the above signals are input. Further, in the above embodiment, the case where a plurality of indoor units have the same capacity has been described, but when a plurality of indoor units having different capacities are installed,
Further, as the operation mode of each indoor unit, the capacity signal of each indoor unit is input to the controller (33) together with the indoor unit operation mode signal indicating whether each indoor unit is in the heating / cooling operating state, and the total cooling / heating operating capacity of the indoor unit is input. Is detected and the operating mode is detected based on this, or the operating mode is detected by inputting the operating mode signal of the outdoor unit, so that the operating mode can be accurately known and optimal control can be performed.

Further, in the above embodiment, the case where the capillary tube (25) having a fixed flow rate is used as the third flow rate controller has been described.
Similarly to the second flow rate controllers (21) and (23), an electric expansion type or the like may be used, and in that case, the valve opening degree is set to the controller (3
3) controlled by.

Furthermore, the switching valve (20) of the indoor unit, the first electric expansion valve (21), etc. may be provided inside the indoor unit main body or outside the indoor unit main body.

〔The invention's effect〕

As described above, according to the present invention, the outdoor unit including the compressor, the switching valve, and the outdoor heat exchanger, and the plurality of indoor units including the indoor heat exchanger are connected via the first and second connection pipes. In an air conditioner that is connected in parallel, one of the plurality of indoor units is switchably connected to the first or second connection pipe, and the middle of the first connection pipe that is connected to the outdoor heat exchanger A gas-liquid separator, a third connecting pipe for connecting the other of the plurality of indoor units and the gas-liquid separator via a flow controller, and the gas-liquid separator and the second connecting pipe. Bypass pipes that are connected to each other and have a heat exchanger that exchanges heat with the pipe switch and the third connecting pipe on the way, and the pipeline depending on the operation mode of each of the plurality of indoor units. By installing a controller that controls the opening and closing of switches, it is possible to connect multiple rooms in parallel. Since the cooling operation and the heating operation can be performed simultaneously or selectively and the flow rate of the refrigerant and the gas-liquid state can be appropriately controlled, it is optimal for the cooling and heating requirements of the space where the indoor unit is installed. Air conditioning operation can be performed, and highly efficient operation can be performed. Furthermore, by simply adding the third connecting pipe for connecting the indoor period, the long connecting pipe for connecting the indoor unit and the outdoor unit can be two conventional ones, and the installation workability is good, and the cost is low.

It is assumed that the indoor unit is provided with a first flow rate controller, the other first flow rate controller of the indoor unit and the gas-liquid separator are connected by a third connecting pipe, and a second line is provided in the middle of the line. A flow rate controller is provided, and the controller adjusts the opening degree of the second flow rate controller according to the operation mode of each indoor unit and the refrigerant state of the connecting pipe between the first and second flow rate controllers. Since the opening / closing of the road switch is controlled, more optimal cooling / heating operation can be performed and more efficient operation can be performed in response to the cooling / heating requirement of the space where each indoor unit is installed.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air conditioner of one embodiment of the present invention, FIG. 2 is an operation state diagram of only the cooling or heating of the embodiment shown in FIG. 1, and FIG. The figure is first
The operation operation state diagram showing the case where the heating operation capacity of the embodiment shown in the figure is larger than the cooling operation capacity, and FIG. 4 is the operation showing the case where the cooling operation capacity of the embodiment shown in FIG. 1 is larger than the heating operation capacity. FIG. 5 is an operation state diagram, FIG. 5 is a flow chart showing a control flow of the controller of the embodiment shown in FIG. 1, and FIG. 6 is a whole focusing on a refrigerant system of an air conditioner of another embodiment of the present invention. FIG. 7 is an overall configuration diagram centering on a refrigerant system of a conventional air conditioner. In the figure, (1): outdoor unit, (2): compressor,
(3): Four-way valve, (4): Outdoor heat exchanger, (8): Accumulator, (9a) to (9c): Indoor unit, (10): Indoor heat exchanger, (13): First connection Piping, (14): Second connection piping, (19): Gas-liquid separator, (21): First electric expansion valve that is the first flow rate controller, (22): Third connection piping ，
(23): A second electric expansion valve which is a second flow rate controller,
(24): Solenoid valve that is a line switch, (25): Capillary tube that is a third flow rate controller, (26): Heat exchange section, (27): Bypass piping, (30a) to (30c): Indoor unit operation controller, (3
1): Temperature sensor, (32): Pressure sensor, (33): Controller, X _V2 , X _V2 ^* : Current and new valve opening command value of the second electric expansion valve, ΔX _V2 : Valve opening the amount of change in the command value, SC: refrigerant supercooling degree of the third connection pipe from the first flow control device toward the second flow controller, SC _L, SC _H: lower limit and upper limit of the control target degree of supercooling It is a value. In the drawings, the same reference numerals and symbols indicate the same or corresponding parts.

Claims (2)

[Claims] 1. An outdoor unit comprising a compressor, a switching valve and an outdoor heat exchanger, and a plurality of indoor units comprising an indoor heat exchanger are connected in parallel via first and second connecting pipes. In the air conditioner, the one of the plurality of indoor units is switchably connected to the first or second connection pipe, and the gas-liquid separator is provided in the middle of the first connection pipe connected to the outdoor heat exchanger. When,
A third connecting pipe for connecting the other of the plurality of indoor units and the gas-liquid separator via a flow rate controller, the gas-liquid separator and the second connecting pipe are connected, and a pipeline is provided on the way. The opening and closing of the pipeline switch is controlled by the switch and the bypass pipe in which a heat exchanger unit for exchanging heat with the third connecting pipe is arranged, and the operation mode of each of the plurality of indoor units. An air conditioner provided with a controller. 2. An outdoor unit consisting of a compressor, a switching valve and an outdoor heat exchanger, and a plurality of indoor units consisting of an indoor heat exchanger and a first flow rate controller with first and second connecting pipes. In the air conditioner connected in parallel via the first connection pipe, which connects one of the plurality of indoor units to the first or second connection pipe in a switchable manner and connects the outdoor heat exchanger. In the middle of the process, the gas-liquid separator and the other first unit of the plurality of indoor units
Connect the flow rate controller of the
The third connection pipe in which the flow controller of No. 3 is arranged, the gas-liquid separator and the second connection pipe are connected, and heat exchange is performed between the pipe switch and the third connection pipe on the way. The degree of opening of the second flow rate controller depending on the bypass pipe in which the heat exchange section is arranged, the operation mode of each of the plurality of indoor units, and the refrigerant state of the connection pipe between the first and second flow rate controllers. And an controller for controlling the opening and closing of the pipeline switch.