JPH0363469A - air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air conditioner in which the connection on the gas pipe side of each heat exchanger can be switched individually to a discharge line and a suction line. Regarding flash prevention measures.

(Prior Art) Conventionally, as shown in FIG.
In an air conditioner in which a plurality of indoor units (bl) to (b3) each having a user-side heat exchanger (c) and a pressure reducing valve (g) are connected in parallel to a discharge line (!
), suction line C1), ) and liquid line (Io) are extended from the outdoor side to the indoor side, and each indoor unit (b
The liquid pipe (e) of each user-side heat exchanger (c) of l) to (b3)
) is connected to the liquid line (ρ) via a separator (d), and the gas pipe side is branched into a first branch pipe (e) and a second branch pipe (e,), and each branch pipe (e),
(eb) is the discharge line CD ) side part a
a
Separator (d) and separator (d) on the suction line (g, ) side
) and the on-off valves (f) and (f,) respectively b
A, each on-off valve (f) is connected according to the air conditioning request,
By alternately switching the opening and closing of (f,), each user side heat exchanger (C) is connected to the indoor units (bl) to (b3) side.
On the outside, the heat exchanger on the heat source side can be switched to the condenser or evaporator to perform heating and cooling operations in each room, depending on the total demand on the indoor side. There is a known technology that attempts to reduce the total power consumption by mutually recovering the heat generated during individual operations.

(Problems to be Solved by the Invention) By the way, when performing heating and cooling operations individually in each room as described above, there are the following problems.

That is, among each indoor unit (bl) to (b3),
For example, the indoor unit (bl) in the center of the diagram is in heating mode,
When the other indoor units (b+) and (b・3) are in simultaneous cooling and heating operation, the flow of refrigerant is as shown by the arrow in the figure. The refrigerant condensed in the heat exchanger (c) on the user side of bl) passes through the liquid pipe (e) and joins with the refrigerant from the liquid line (g) in the separator (dCC 0) on the liquid line (J2) side. Separator (
d) to another indoor unit (b+).

(b3) The flow CC branches into the liquid pipes (e) and (e), but at that time, the indoor unit () (during heating operation)
Flash gas may be generated in the liquid refrigerant in the liquid pipe (e) of bl) due to the pressure reducing effect of the pressure reducing valve (g). Then, due to this flash gas, the refrigerant becomes two phases, liquid and gas, and the gas is unevenly distributed in the liquid, resulting in uneven flow of the refrigerant supplied to each indoor unit (bl) (b3). The thermal efficiency of the user-side heat exchangers (c) and (c) decreases, resulting in insufficient cooling capacity in the indoor units (b+) and (b3).

The present invention has been made in view of the above, and its purpose is to provide a means for preventing the generation of flash gas in the liquid pipes of indoor units during heating operation when each indoor unit is in simultaneous cooling and heating operation. This effectively prevents the drift of refrigerant to each indoor unit during cooling operation, thereby ensuring cooling capacity.

(Means for Solving the Problem) In order to achieve the above object, the solving means of the present invention bypasses a part of the refrigerant in the liquid pipe to the suction side in an indoor unit during heating operation, and the refrigerant to be bypassed is The purpose is to subcool the refrigerant in the liquid pipe by reducing the pressure.

Specifically, the first solution is as shown in FIG.
), variable capacity compressor (1), heat source side heat exchanger (2), and heat source side pressure reducing valve with adjustable opening (2)
5), and a plurality of indoor units (B), each having a usage-side heat exchanger (5) and a usage-side pressure reducing valve (51), are connected in parallel to the outdoor unit (A) having the usage-side heat exchanger (5) and the usage-side pressure reducing valve (51). Targets air conditioning equipment.

A discharge line (31) extending from the discharge side of the compressor (1), a suction line (32) extending from the suction side of the compressor (1), and a harmonic end of the heat source side heat exchanger (2) A liquid line (33) extending from the section and a heat source side heat exchanger (2)
Connect the gas pipe side of the discharge line (31) and suction line (
32') and an outdoor connection switching means (21) for switching between the liquid line (32') and a liquid line (
33), a gas pipe (5a) extending from the gas side end of the utilization side heat exchanger (5), and a discharge line (31) branched from the gas pipe (5a), respectively.
), the second indoor branch pipe (32b) that communicates with the suction line (32), and the gas pipe (5a) side of each user-side heat exchanger (5). Connect the first indoor branch pipe (31 b) and the second indoor branch pipe (3
2b) and an indoor connection switching means (35) for switching between the two.

Furthermore, the liquid pipe (33b) in each indoor unit (B)
and the second indoor branch pipe (32b), a bypass passage (54) for bypassing a part of the refrigerant in the liquid pipe (33b), and a bypass opening/closing means (for opening and closing the bypass passage (54)). 54a), a pressure reducing mechanism (54b) interposed in the bypass path (54), and the bypass path (54).
a heat exchange mechanism (54c) for exchanging heat between the refrigerant depressurized by the pressure reducing mechanism (54b) and the refrigerant in the liquid pipe (33b);
) and the indoor unit (B)... When individual air conditioning and heating are operated simultaneously, in the indoor unit (B) that is in heating mode, connect the gas pipe (5a) of the user-side heat exchanger (5) to the first indoor unit. Indoor connection switching means (35) to switch to branch pipe (31a)
) and an operation control means (101) which controls the bypass opening/closing means (54a) to open.

The second solution, as shown in FIG. An individual controller that controls the indoor connection switching means (35) to switch the connection of the gas pipe (5a) of the exchange a (5) to the first indoor branch pipe (31a), and also controls the bypass opening/closing means (54a) to open. An operation control means (102) is provided.

The third solution is as shown in FIG.
, an air conditioner having a main refrigerant circuit (3) formed by sequentially connecting a heat source side heat exchanger (2), a heat source side pressure reducing valve (25), a user side pressure reducing valve (51), and a user side heat exchanger (5). Targeting equipment.

Then, the heat source side pressure reducing valve (25) - the user side pressure reducing valve (5)
A bypass passage (1) for bypassing a part of the liquid refrigerant in the main refrigerant circuit (3) is provided between the liquid pipe between 1) and the suction pipe of the compressor (1).
27), and the bypass passage (27) is provided with a pressure reducing mechanism (27a) for reducing the pressure of the refrigerant to be bypassed.
and a heat exchange mechanism (27b) for exchanging heat between the refrigerant depressurized by the pressure reducing mechanism (27a) of the bypass passage (27) and the liquid refrigerant in the liquid pipe of the main refrigerant circuit (3). It is something.

(Function) With the above configuration, in the invention of claim (1), when each indoor unit (B), . 3
5), the connection of the gas pipe (5a) of the user-side heat exchanger (5) is switched to the discharge line (31) side, and the discharged refrigerant is condensed in the user-side heat exchanger (5) and transferred to the liquid pipe (33b). ) to the liquid line (33), while in other indoor units (B) and (B) during cooling operation, the indoor connection switching means (35
), the connection of the gas pipe (5a) of the user side heat exchanger (5) is switched to the suction line (32) side, and the connection of the gas pipe (5a) of the user side heat exchanger (5) is switched to the suction line (32) side, and the connection of the gas pipe (5a) of the user side heat exchanger (5) is switched to the suction line (32) side,
The refrigerant flowing into the liquid pipes (33b) and (33b) from 3) is depressurized by the user-side pressure reducing valve (51), and the refrigerant flows into each user-side heat exchanger (
After being evaporated in step 5), it flows into the suction line (32).

At that time, in the indoor unit (B) during heating operation,
The operation control means (101) controls the opening/closing means (54a) of the bypass path (54) to open, and a part of the condensed and liquefied refrigerant in the liquid pipe (33b) is bypassed to the suction line (32) side. The pressure is reduced in the capillary tube (54b), and the refrigerant is evaporated by heat exchange with the liquid refrigerant in the liquid pipe (33b) in the piping heat exchanger (54c). Therefore, the liquid pipe (3
The liquid refrigerant in 3b) is supercooled in this piping heat exchanger (54c), and generation of flash gas is prevented. That is, drifting of the refrigerant in the liquid line (33) after merging is prevented, and the cooling capacity of each indoor unit (B), (B) is ensured.

In the invention of claim (2), the individual operation control means (102)
As a result, the opening/closing means (54a) of the bypass path (54) in the indoor unit (B) during heating operation is controlled to open, regardless of the operating state of the other indoor units (B), etc. , the control for preventing the generation of flash gas is performed only by the operating conditions of the indoor unit (B), and the same effect as the invention of claim (1) can be achieved with a simple configuration. can.

In the invention of claim (3), a part of the refrigerant in the liquid pipe of the main refrigerant circuit (3) is bypassed to the bypass path (27), is depressurized by the pressure reduction mechanism (27a), and is depressurized by the heat exchange mechanism (27c). The liquid refrigerant is supercooled by heat exchange with the depressurized refrigerant, so during both cooling and heating operations, after being condensed in the heat source side heat exchanger (2) or the user side heat exchanger (5), the liquid refrigerant is The pressure is reduced by the pressure reducing valve (25) or the usage side pressure reducing valve (51), thereby preventing the generation of flash gas in the refrigerant in the liquid pipe.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows the overall configuration of an air conditioner (X) according to an embodiment of the present invention, in which one outdoor unit (A) is provided with a plurality of indoor units (B), (B)... 3
It has a so-called multi-type configuration in which multiple units (stands) are connected.

In the above outdoor unit (A), (1) is a compressor, (
2) is an outdoor heat exchanger as a heat source side heat exchanger equipped with an outdoor fan (26), and (21) is the outdoor heat exchanger (2).
(25) is an outdoor electric expansion valve as a pressure reducing valve on the heat source side, (43) is for storing liquid refrigerant. The receiver (41) is an accumulator for separating liquid refrigerant in the suction refrigerant.

On the other hand, each of the indoor units (B), etc. has the same configuration, and all of them have an indoor heat exchanger ( 5) Reduce the pressure of the refrigerant during cooling operation,
It is equipped with an indoor electric expansion valve (51) which is a user-side pressure reducing valve that adjusts the refrigerant flow rate during heating operation.

From the discharge side of the compressor (1), a discharge line (
31), suction lines (32) extend from the suction side, while liquid lines (33) extend from the light side end of the outdoor heat exchanger (2), and the three refrigerant pipes (
31) to (33) extend from the outdoor side to the indoor side. The above outdoor unit (A) and each indoor unit (
B).

Each device is connected to the three refrigerant pipes (31) to (33).
) connected to each heat exchanger (2) and (5).

A main refrigerant circuit (3) is constructed that allows heat to be transferred between...

Here, to explain in detail the connection relationship of the refrigerant piping described above, in the outdoor unit (A), the outdoor heat exchanger (2
) A gas pipe (22) extends from the gas side end of the pipe (22), and the gas pipe (22) is connected to a first outdoor branch pipe (22-1) communicating with the discharge line (31) and a suction line (32). The first outdoor branch pipe (22-2) is branched into a second outdoor branch pipe (22-2) to be connected.
．． The ends of the second outdoor branch pipes (22-1) and (22-2) are connected to two opposing connection boats of the four-way switching valve (21), so that the four-way switching valve (21) When switching to the broken line side in the figure, the gas pipe (22) of the outdoor heat exchanger (2)
As a result of being connected to the suction line (32) via the branch pipe (22-2), the outdoor heat exchanger (2) functions as an evaporator, while the four-way switching valve (21) switches to the solid line side in the figure. When the gas pipe (22) of the outdoor heat exchanger (2) is replaced with the first branch pipe (
As a result of being connected to the discharge line (31) via 22-1), the outdoor heat exchanger (2) functions as a condenser. The other connection boat of the four-way switching valve (21) is connected to the second outdoor branch pipe (22-1) via a capillary tube (23).

In addition, in the indoor unit (B), the above discharge line (
31), the indoor end of the suction line (32) and the liquid line (33) are connected to the first to third flow dividers (31a) to (31), respectively.
33a), while a liquid pipe (33b) extends from the light side end of each indoor heat exchanger (5) and connects to the third flow divider (33a).
33a). In addition, each indoor heat exchanger (5
) A gas pipe (5a) extends from the gas side end of the pipe (5a), and the gas pipe (5a) further branches into a first indoor branch pipe (31b) and a second indoor branch pipe (32b). The first indoor branch pipe (31 b) is connected to the first flow divider (31a) through the first on-off valve (52), and the second indoor branch pipe (32b) is connected to the second flow divider (31a) through the second on-off valve (53). (32a), and further connected to the liquid pipes (33b) of the indoor heat exchanger (5).
is connected to the third flow divider (33a). That is,
The first indoor on-off valve (52) opens and the second indoor on-off valve (52) opens.
3) is closed, the indoor heat exchanger (5) gas pipe (
5a) is connected to the discharge line (31), the indoor heat exchanger (5) functions as a condenser, while the first indoor on-off valve (52) is closed and the second indoor on-off valve (53) is opened. Sometimes, the gas pipe (5a) of the indoor heat exchanger (5) is connected to the suction line (32), so that the indoor heat exchanger (5) functions as an evaporator.

Here, as a feature of the present invention, in each indoor unit (B), a part of the refrigerant in the liquid pipe (33b) is bypassed between the liquid pipe (33b) and the second indoor branch pipe (32b). A bypass passage (54) is provided, and the bypass passage (54) is provided with a third indoor opening/closing valve (54a) as an opening/closing means for opening and closing the bypass passage (54).
) and a capillary tube (54b) serving as a decompression mechanism for reducing the pressure of the refrigerant flowing through the capillary tube (54b).
) A piping heat exchanger (54c) serving as a heat exchange mechanism for exchanging heat between the refrigerant depressurized by the refrigerant in the liquid pipe (33b) is provided in order from the upstream side of the bypass path (54). . That is, the third indoor on-off valve (54a
) is opened, a part of the refrigerant in the liquid pipe is bypassed to the suction side, the pressure is reduced in the capillary tube (54b), and the liquid refrigerant in the liquid pipe (33b) is evaporated and cooled by the reduced pressure. By supercooling the liquid, flash in the liquid pipe (33b) is prevented. The on-off valves (52), (53), (54a), capillary tube (54b), piping heat exchanger (54c), etc. are integrally housed in the kit (56).

Furthermore, the device is equipped with sensors (Th
l) is an indoor liquid temperature sensor that detects the liquid refrigerant temperature of the indoor heat exchanger (5), (T h2) is an indoor gas temperature sensor that detects the gas refrigerant temperature of the indoor heat exchanger (5), (T h3) is a room temperature sensor that detects the indoor air temperature, (T h4) is an outdoor liquid temperature sensor that detects the liquid refrigerant temperature of the outdoor heat exchanger (2), and (T h5) is the gas refrigerant temperature of the outdoor heat exchanger (2). (T h[l) is an outdoor temperature sensor that detects outside air temperature, (T h7) is a compressor) (
1) A discharge pipe sensor that detects the discharge pipe temperature (L ps
) is placed in the suction line (32) and is a low pressure sensor for detecting low pressure, and (Hps) is placed in the discharge line (31) and is a high pressure sensor for detecting high pressure.

In the air conditioner (X), a controller (101) for controlling the operation of the entire device is placed outside the room, while each indoor unit (B), . . . B) An indoor controller (102) for controlling individual operations is arranged, and the two controllers (101) and (102) control the operation of the compressor (1) according to the detected values of each sensor. It is designed to control the capacity, the opening degree or opening/closing of each pressure reducing valve (25), (51), . . . . Note that (57) is an indoor fan provided in each indoor unit (B).

When operating the air conditioner (X), each indoor unit (B),
..., each of the indoor controllers (102),
..., when the indoor request is a cooling request, the gas pipe (5a) of the indoor heat exchanger (5) is connected to the suction line (
32), the refrigerant whose pressure has been reduced by the indoor electric expansion valve (51) flows so as to evaporate in the indoor heat exchanger (5). In addition, when the indoor request is a heating request, the connection on the gas pipe side of the indoor heat exchanger (5) is connected to the discharge line (31
) side, and the refrigerant discharged from the compressor (1) flows so as to be condensed and liquefied in the indoor heat exchanger (5).

On the other hand, in the outdoor unit (A), the controller (
101), all indoor units (B).

When the overall request for... is a cooling request, the four-way switching valve (2
1) is switched to the solid line side in the figure, and the discharged refrigerant flows to be condensed and liquefied in the outdoor heat exchanger (2), so that the outdoor heat exchanger (2) functions as a condenser, and all indoor When the overall request of the units (B), . . . is a heating request, the four-way switching valve (21) is switched to the dashed line side in the figure,
The refrigerant whose pressure is reduced by the outdoor electric expansion valve (25) flows to evaporate in the outdoor heat exchanger (2).
is made to function as an evaporator. That is, each indoor unit (B), . . . can be individually and simultaneously cooled and heated while minimizing the operating capacity of the compressor (1).

For example, in Figure 2, when the rightmost indoor unit (B) is in heating operation and the other indoor units (B) and (B) are in cooling operation, the rightmost indoor unit (
In B), the first indoor on-off valve (52) opens and the second indoor on-off valve (53) closes, and the refrigerant flowing from the discharge line (31) via the first separator (31a) flows into the indoor heat exchanger. (5
) is condensed and sent from the liquid pipe (33b) to the third separator' (33
a) and joins with the refrigerant in the liquid line (33). On the other hand, in the other indoor units (B), (B), the first indoor on-off valves (52), (52) are closed, the second indoor on-off valve (53) is opened, and the refrigerant is discharged from the third separator (33a). Liquid pipe (33b)
, (33b), and the indoor electric expansion valve (51)
After being depressurized and evaporated in each indoor heat exchanger (5), the second
It flows to the suction line (32) via the separator (32a).

In addition, in the outdoor unit (A), when the cooling demand is greater than the demand for the entire room, the four-way switching valve (21
) is switched to the solid line side in the figure, and the refrigerant flowing from the discharge line (31) is condensed in the outdoor heat exchanger (2) and flows from the liquid line (33) to the third separator (33a). .

Here, during simultaneous cooling and heating operation in which each indoor unit (B), . . . individually performs cooling operation and heating operation, the indoor controller (101)
02), the third indoor on-off valve (54a) of the bypass path (54) of the indoor unit (B) during heating operation is controlled to open.

That is, the controller (101) is an operation control means that controls to open the third indoor opening/closing valve (opening/closing means) (54a) of the bypass path (54) of the indoor unit (B) in the heating operation during the simultaneous heating and cooling operation. It functions as a Further, in the invention of claim (2), as described later, in the indoor unit (B) during heating operation, the third indoor on-off valve (54a) of the bypass path (54) is opened by the indoor controller (102). The indoor controller (102) functions as an individual operation control means.

Therefore, in the invention of claim (1), when each indoor unit (B), . (opening/closing means) is controlled to open.

In that case, when each indoor unit (B), . . . is in simultaneous heating and cooling operation, for example, in FIG. is in cooling operation and the refrigerant is flowing as shown by the arrow in the figure, the liquid pipes (3) of each indoor unit (B),...
In 3b), in the indoor unit (B) during heating operation, the refrigerant is condensed and liquefied by the indoor heat exchanger (5).
In order to adjust the flow rate of refrigerant, an indoor electric expansion valve (51)
It is squeezed to some extent and receives a decompression effect. Therefore, due to the pressure reduction effect, there is a possibility that some percentage of gasified refrigerant may be mixed into the liquid. Then, the third separator (33a
), the indoor unit (B) is in another cooling operation after merging with the refrigerant in the liquid line (33).

If flash gas is mixed in when branching into the liquid refrigerant pipes (33b) and (33b) in (B), the flash gas will be unevenly distributed in the liquid refrigerant, resulting in uneven flow of the refrigerant. , the thermal efficiency of each indoor heat exchanger (5) (5) decreases, and there is a risk that the cooling capacity of each indoor unit (B) (B) will be insufficient.

Here, in the present invention, each indoor unit (B).

When the indoor unit (B) is in the heating operation, the controller (101) controls the third
When the indoor on-off valve (54a) is opened, a portion of the condensed and liquefied refrigerant in the liquid pipe (33b) flows into the second indoor branch pipe (32b).
The liquid refrigerant is bypassed to the side, is depressurized by the capillary tube (54b), and is evaporated by heat exchange with the liquid refrigerant in the liquid tube (33b) in the piping heat exchanger (54c).
The liquid refrigerant inside is supercooled by this piping heat exchanger (54c), and generation of flash gas can be effectively prevented. Therefore, uneven flow of the refrigerant in the third separator (33a) can be effectively prevented, and each indoor unit (B),
The cooling capacity (B) can be effectively secured.

Next, in the invention of claim (3), the indoor controller (102) of each indoor unit (B) controls whether the other indoor units (B), . . . are in cooling operation or heating operation.
When the indoor unit (B) is in heating operation, the third indoor on-off valve (54a) is controlled to open.

Therefore, in the invention of claim (2), in the indoor unit (B) during heating operation, the third indoor on-off valve (54a) is
is opened, the same effect as the invention of claim (1) above can be obtained without considering the operating conditions of other indoor units (B), etc., and therefore, with simple control. Unbalanced flow of refrigerant can be prevented.

In addition, in the above embodiment, three refrigerant pipes (31) (32
) and (33) extend from the outdoor side to the indoor side, and a bypass path (54) for supercooling the liquid refrigerant is provided on the indoor side. The present invention can also be applied to an air conditioner having the following configuration. FIG. 3 shows a second embodiment according to the invention of claim (3), in which the outdoor unit (A) includes a compressor (1), a four-way switching valve (21), an outdoor heat exchanger (2), While an outdoor electric expansion valve (25) and a receiver (43) are arranged, an indoor electric expansion valve (51) and an indoor heat exchanger (5) are arranged in the indoor units (B), (B), A main refrigerant circuit (3) is constructed by sequentially connecting the above-mentioned devices with refrigerant piping. And the receiver (43) of the main refrigerant circuit (3)
) and the indoor units (B), a bypass path (27) for bypassing the liquid refrigerant is provided from the liquid pipe toward the suction pipe of the compressor (1), and the bypass The passage (27) includes a capillary tube (27a) from the upstream side as a pressure reduction mechanism that reduces the pressure of the refrigerant to be bypassed.
and a piping heat exchanger (as a heat exchange mechanism for exchanging heat with the liquid refrigerant depressurized in the capillary tube <27a>).
27b) is provided.

That is, in the invention of claim (3), the liquid refrigerant in the liquid pipes of the main refrigerant circuit (3) is supercooled by the heat exchange mechanism (27b) during both cooling and heating operations of the air conditioner. The electric expansion valve (25) or (51) or (51) reduces the pressure and prevents the possibility of flash gas generation in the liquid refrigerant, which is easily gasified, and has the same effect as the first embodiment, especially during cooling operation. can be obtained.

(Effects of the Invention) As explained above, according to the invention of claim (1), a plurality of indoor units are connected in parallel to an outdoor unit, and the discharge line, suction line, and liquid line are connected from the outdoor side. In an air conditioner that extends indoors and is configured such that the connection of the gas pipes of each heat exchanger can be switched between a discharge line and a suction line, from the liquid pipe of the indoor unit connected to the liquid line. A part of the refrigerant is bypassed to the suction side gas pipe of the indoor heat exchanger that communicates with the suction line, and a refrigerant pressure reduction mechanism, the refrigerant whose pressure has been reduced by the pressure reduction mechanism, and the liquid refrigerant in the liquid pipe are passed through the bypass line. We installed a heat exchange mechanism that exchanges heat with the liquid line, and when each indoor unit is in simultaneous cooling and heating operation, the bypass path of the indoor unit in heating operation is opened. Unbalanced flow of refrigerant can be effectively prevented, and therefore,
The cooling capacity of the indoor unit during cooling operation can be effectively ensured.

According to the invention of claim (2), in the air conditioner having the same configuration as the invention of claim (1), the bypass path is uniformly opened in indoor units during heating operation, so that other Generation of flash gas can be prevented without considering the operating state of the indoor unit, and therefore, the same effect as the invention of claim (1) can be obtained with simple control.

According to the invention of claim (3), there is provided an air conditioner having a normal main refrigerant circuit formed by sequentially connecting a compressor, a heat source side heat exchanger, a heat source side pressure reducing valve, a user side pressure reducing valve, and a user side heat exchanger. In the device, a part of the refrigerant is bypassed from the liquid pipe between the heat source side pressure reducing valve and the usage side pressure reducing valve to the suction pipe, and after reducing the pressure of the bypassed refrigerant, it exchanges heat with the liquid refrigerant in the liquid pipe, Since the refrigerant in the liquid pipes of the main refrigerant circuit is supercooled, flash gas is generated in the refrigerant, which is condensed in the heat exchanger and then reduced in pressure by the pressure reducing valve, making it easier to gasify during both heating and cooling operations. can be effectively prevented.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the configuration of the present invention. FIG. 2 is a refrigerant piping system diagram showing the configuration of the air conditioner according to the first embodiment, and FIG. 3 is a refrigerant piping system diagram showing the configuration of the air conditioner according to the second embodiment. FIG. 4 is a partial refrigerant piping system diagram for explaining the uneven flow state of refrigerant in a conventional air conditioner. l Compressor 2 Outdoor heat exchanger (heat source side heat exchanger) 3 Main refrigerant circuit 5 Indoor heat exchanger (user side heat exchanger) 21 Four-way switching valve (outdoor connection switching means) 25 Outdoor electric expansion valve (heat source side Pressure reducing valve) 31 Discharge line 32 Suction line 33 Seven lines 31b, 32b 1st. Second indoor branch pipe 35 Indoor connection switching means 51 Indoor electric expansion valve (heat source side pressure reducing valve) 54.27
Bypass path 54a Third on-off valve (opening/closing means) 54b, 27a Capillary tube (pressure reduction mechanism) 54c, 27b Piping heat exchanger (heat exchange mechanism)

Claims (1)

[Claims] (1) Variable capacity compressor (1), heat source side heat exchanger (2)
and an outdoor unit (A) having a heat source side pressure reducing valve (25) whose opening degree can be adjusted, and a plurality of indoor units (B) having a user side heat exchanger (5) and a user side pressure reducing valve (51).
), ... are connected in parallel, a discharge line (31) extending from the discharge side of the compressor (1).
) and a suction line (3) extending from the suction side of the compressor (1).
2), a liquid line (33) extending from the liquid side end of the heat source side heat exchanger (2), and a gas pipe side connection of the heat source side heat exchanger (2) to the discharge line (31) and the suction line. (32) and an outdoor connection switching means (21) for switching between the user side heat exchanger (32) and a liquid pipe (33b) extending from the liquid side end of each user side heat exchanger (5) and connected to the liquid line (33); A gas pipe (5a) extending from the gas side end of the heat exchanger (5);
), the first indoor branch pipe (31b) communicates with the discharge line (31), the second indoor branch pipe (32b) communicates with the suction line (32), and each of the user-side heat exchangers (5). ) to the first indoor branch pipe (31b) and the second indoor branch pipe (32b), and each indoor unit (B) The liquid pipe (33b) is provided between the liquid pipe (33b) and the second indoor branch pipe (32b).
Bypass path (54) that bypasses a part of the refrigerant in b)
, a bypass opening/closing means (54a) for opening and closing the bypass passage (54), a pressure reduction mechanism (54b) provided in the bypass passage (54), and a pressure reduction mechanism (54b) for the bypass passage (54). The depressurized refrigerant and the liquid pipe (33b
) and the indoor unit (B), which performs heat exchange with the refrigerant in 5) connect the gas pipe (5a) to the first indoor branch pipe (3).
1a), and an operation control means (101) that controls an indoor connection switching means (35) to open the bypass opening/closing means (54a). (2) Variable capacity compressor (1),
For an outdoor unit (A) having a heat source side heat exchanger (2) and a heat source side pressure reducing valve (25) whose opening degree is adjustable, a user side heat exchanger (5) and a user side pressure reducing valve (51) In an air conditioner in which a plurality of indoor units (B), . . . having
) and a suction line (3) extending from the suction side of the compressor (1).
2), a liquid line (33) extending from the liquid side end of the heat source side heat exchanger (2), and a gas pipe side connection of the heat source side heat exchanger (2) to the discharge line (31) and the suction line. (32) and an outdoor connection switching means (21) for switching between the user side heat exchanger (32) and a liquid pipe (33b) extending from the liquid side end of each user side heat exchanger (5) and connected to the liquid line (33); A gas pipe (5a) extending from the gas side end of the heat exchanger (5);
), the first indoor branch pipe (31b) communicates with the discharge line (31), the second indoor branch pipe (32b) communicates with the suction line (32), and each of the user-side heat exchangers (5). ) to the first indoor branch pipe (31b) and the second indoor branch pipe (32b), and each indoor unit (B) , the liquid pipe (33b) is provided between the liquid pipe (33b) and the second indoor branch pipe (32b);
Bypass passage (54) that bypasses a part of the refrigerant of 3b)
), a bypass opening/closing means (54a) for opening and closing the bypass passage (54), a pressure reduction mechanism (54b) provided in the bypass passage (54), and a pressure reduction mechanism (54b) of the bypass passage (54). ) and the liquid pipe (33
a heat exchange mechanism (54c) that exchanges heat with the refrigerant of b);
When the indoor unit (B) is in heating operation, the user side heat exchanger (5
) to connect the gas pipe (5a) to the first indoor branch pipe (31a).
An air conditioner characterized by comprising: an individual operation control means (102) that controls an indoor connection switching means (35) to open the bypass opening/closing means (54a). (3) Main refrigerant formed by sequentially connecting a compressor (1), a heat source side heat exchanger (2), a heat source side pressure reducing valve (25), a user side pressure reducing valve (51), and a user side heat exchanger (5) In the air conditioner having the circuit (3), the main refrigerant circuit is provided between the liquid pipe between the heat source side pressure reducing valve (25) and the user side pressure reducing valve (51) and the suction pipe of the compressor (1). (3) a bypass passage (27) that bypasses a part of the liquid refrigerant; and a pressure reduction mechanism (2) provided in the bypass passage (27) for reducing the pressure of the refrigerant to be bypassed.
7a) and the pressure reducing mechanism (27a) of the bypass path (27).
) and a heat exchange mechanism (27b) for exchanging heat between the refrigerant depressurized in the main refrigerant circuit (3) and the liquid refrigerant in the liquid pipe of the main refrigerant circuit (3).