JP2522363B2 - Air conditioner - Google Patents

Description

TECHNICAL FIELD The present invention relates to a multi-room type air conditioner in which a plurality of indoor units are connected to one outdoor unit, and in particular, for each indoor unit. The present invention relates to an air conditioner capable of performing heating and cooling selectively or simultaneously.

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

FIG. 6 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 an outdoor unit of an 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 liquid receiver, and 8 is an accumulator. Then, these constitute the outdoor unit 1. Further, 9a to 9c are the outdoor units 1
Each of the indoor units is connected to the indoor unit, 10 is an indoor heat exchanger, 11 is a check valve, and 12 is an expansion valve, which constitute the indoor units 9a to 9c. Further, 13 and 14 are first and second connection pipes that connect the indoor units 9a to 9c and the outdoor unit 1.

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 is supplied from the first connecting pipe 13 to each indoor unit 9a.
To 9c, and the indoor heat exchanger 10 exchanges heat with the indoor air (heating) to condense and liquefy. The refrigerant liquid liquefied in each of the indoor units 9a to 9c merges in the second connection pipe 14 through the check valve 11 and further flows into the expansion valve 6 through the liquid receiver 7 where low temperature The pressure is reduced to the gas-liquid two-phase state and flows into the outdoor heat exchanger 4. The refrigerant flowing into the outdoor heat exchanger 4 evaporates by exchanging heat with the outside air, becomes a gas state, and forms a circulation cycle in which the refrigerant is sucked into the compressor 2 again.

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 the 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, passes through the liquid receiver 7, and is connected to each indoor unit 9a through the connection pipe 14. Flow into 9c. And each indoor unit 9a-9c
The refrigerant liquid that has flown into is decompressed by the expansion valve 12 to a low-temperature gas-liquid two-phase state, is heat-exchanged (cooled) with the indoor air in the indoor heat exchanger 10, becomes a gas state, and merges again in the connecting pipe 13 It is sucked into the compressor 2.

[Problems to be Solved by the Invention] Since the conventional multi-room air conditioner is configured as described above, all the indoor units 9a to 9c need to perform heating operation or cooling operation. , There is a possibility that heating will be performed in a place where cooling is required, or cooling may be performed in a place where heating is required.

In particular, when installing this type of multi-room air conditioner in a large building, the air-conditioning load is significantly different in the interior and perimeter sections, or in office rooms such as general offices and computer rooms. This situation is expected. In addition, in cases such as tenant buildings,
Since the heat load changes each time the borrower changes,
It is impossible to divide into zones such as cooling zone and heating zone. Further, it is not practical to install two cooling indoor units and two heating indoor units in the same room to cope with this, because the equipment cost is high.

Therefore, according to the present invention, even if a plurality of indoor units are connected to one outdoor unit, the cooling or heating operation is selectively or individually performed for each indoor unit in response to a cooling and heating request of a space in which each indoor unit is installed. It is an object to provide an air conditioner that can be simultaneously performed.

[Means for Solving the Problem] In the air conditioner according to claim 1, a gas-liquid separator is provided in the middle of the first connection pipe or the second connection pipe, and one of the plurality of indoor units is provided with One of the first connection pipe and the second connection pipe is switchably connected to the first connection pipe or the second connection pipe, and the other one of the first connection pipe and the second connection pipe is connected to the third connection pipe via a flow control device. The gas-liquid separator provided is connected, and the gas-liquid separator and the first connection pipe or the second connection pipe not provided with the gas-liquid separator are connected by a bypass pipe, and a third pipe is connected to the bypass pipe. The heat exchange part for exchanging heat between the gas-liquid separation device of the connection pipe and the flow rate control device is provided.

In the air conditioner according to claim 2, the gas-liquid separation device and the first connection pipe or the second connection pipe not provided with the gas-liquid separation device are connected by a bypass pipe via the flow control device, and the bypass pipe is connected. The pipe is provided with a heat exchange section for exchanging heat between the gas-liquid separation device of the third connection pipe and the flow rate control device.

[Operation] In the air conditioner of the present invention, in the case of heating-based simultaneous heating and cooling operation, high-pressure gas refrigerant is introduced from the second or first connection pipe to each indoor unit in the heating operation state to perform heating. . A part of the heated refrigerant flows into the indoor unit in the cooling operation state from the third connection pipe, exchanges heat (cooling), and then flows into the first or second connection pipe. on the other hand,
The other refrigerant passes through the flow rate control device of the third connecting pipe to the first
Alternatively, it flows into the second connection pipe, merges with the refrigerant that has passed through the indoor unit in the cooling operation state, and returns to the outdoor unit.

In the case of simultaneous cooling and heating operation mainly for cooling, the high-pressure gas is heat-exchanged in an arbitrary amount by the outdoor heat exchanger to be in a two-phase state and flow into the gas-liquid separation device from the first connecting pipe. Then, the gas-liquid separation device separates the gas and the liquid, introduces the gaseous refrigerant gas into the indoor unit in the heating operation state, performs heating, and flows into the third connection pipe. Further, the other liquid liquid refrigerant flows into the bypass pipe and the third connection pipe, and the refrigerant flowing into the bypass pipe is heat-exchanged with the refrigerant flowing into the third connection pipe in the heat exchanging portion, and then the second Or, it flows into the first connection pipe.
On the other hand, the refrigerant flowing into the third connection pipe merges with the refrigerant from the indoor unit in the heating operation state and flows into each indoor unit in the cooling operation state. The refrigerant that has flowed into the indoor unit in the cooling operation state performs heat exchange (cooling), and after heat exchange, is guided to the outdoor unit side through the second or first connection pipe and returns to the compressor again.

In the case of only the heating operation, the refrigerant is introduced into each indoor unit from the outdoor unit through the second or first connection pipe. Then, heat is exchanged (heated) and returns to the outdoor unit through the third connecting pipe.

Further, in the case of only the cooling operation, the heat is exchanged (cooled) by being introduced into each indoor unit through the first or second connecting pipe and the third connecting pipe. Then, the heat-exchanged refrigerant returns to the outdoor unit through the second or first connection pipe.

[Examples] 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. Also, FIGS. 2 to 4
The figure shows the operating state during the heating and cooling operation in the embodiment of FIG. 1, FIG. 2 is a refrigerant circulation diagram showing the operating state of only cooling or heating, and FIGS. Fig. 3 shows the operation of operation, and Fig. 3 shows the operation state of heating (when the heating operation capacity is larger than the cooling operation capacity) and Fig. 4 shows the operation operation of the cooling mainly (when the cooling operation capacity is larger than the heating operation capacity). It is a refrigerant circulation diagram showing. And
FIG. 5 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, as in the conventional example, a case where one outdoor unit and three indoor units are connected will be described, but the same is basically true when four or more indoor units are connected.

In the figure, 19 is a gas-liquid separator provided in the middle of the first connection pipe 13, and has a function as a gas-liquid separator for separating the refrigerant into a gas and a liquid. Reference numeral 20 is a three-way switching valve that connects one of the indoor heat exchanger 10 to the first connecting pipe 13 and the second connecting pipe 14 in a switchable manner, and 21 is a first connecting pipe connected to the other one of the indoor heat exchanger 10. It is the 1st electric expansion valve which is the 1st flow control device. The three-way switching valve 20, the indoor heat exchanger 10, and the first electric expansion valve 21 constitute each indoor unit 9a-9c. Further, 22 is the first electric expansion valve 21 of each indoor unit 9a-9c.
Side is connected to the lower part of the gas-liquid separator 19 of the first connection pipe 13, and 23 is a second connection pipe provided in the third connection pipe 22.
It is an electric expansion valve which is a flow rate control device. 24 is a solenoid valve that functions as an opening / closing device, 25 is a capillary tube that functions as a flow rate control device, and 26 is heat exchange between the gas-liquid separator 19 of the third connecting pipe 22 and the second electric expansion valve 23. Heat exchange section,
Reference numeral 27 is a bypass pipe branching from a substantially central portion in the height direction of the gas-liquid separator 19 and connected to the second connection pipe 14. The solenoid valve 24, the capillary tube 25, and the heat exchange section 26 are provided in the middle of the bypass pipe 27.

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 side to the indoor side by the second connecting pipe 14, and is discharged to each indoor unit 9a.
Through 9c, each of the three-way switching valves 20 flows into the indoor heat exchanger 10, and heat is exchanged (heated) to be condensed and liquefied. Then, the refrigerant in the liquid state passes through the first electric expansion valve 21, flows into the third connecting pipe 22, joins, and is reduced to a low pressure by the electric expansion valve 23 which is the second flow rate control device. The pressure is reduced.
Then, the refrigerant depressurized to a low pressure passes through the gas-liquid separator 19 and the first connection pipe 13, and then the outdoor heat exchanger 4 of the outdoor unit 1.
Into the gas state, where it is heat-exchanged to become a gas state and is again sucked into the compressor 2. In this way, the circulation cycle is configured and the 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 from the first connection pipe 13 via the gas-liquid separator 19 to the third connection pipe 22. To the indoor unit 9a through the second electric expansion valve 23 in the fully opened state.
Flow into ~ 9c. The refrigerant flowing into each indoor unit 9a-9c is the first
Indoor heat exchanger is decompressed to low pressure by the electric expansion valve 21 of
It flows into 10, and exchanges heat with the indoor air (cooling), evaporates and is gasified. Then, the refrigerant in the gas state passes through the three-way switching valve 20, the second connection pipe 14, and the compressor 2 again.
It constitutes a circulation cycle that is sucked into and performs cooling operation.

Next, the heating-based simultaneous cooling and heating operation will be described with reference to FIG.

First, the refrigerant discharged from the compressor 2 flows from the second connection pipe 14 into the indoor units 9b, 9c in the heating operation state via the three-way switching valve 20, and the heat exchange in the indoor heat exchanger 10 ( heating)
Then, the refrigerant is condensed and liquefied. Then, the flow rate of the condensed and liquefied refrigerant is controlled by the first electric expansion valve 21 so as to be in a slightly supercooled state, and flows into the third connection pipe 22.
Part of this refrigerant enters the indoor unit 9a in the cooling operation state,
After being decompressed by the first electric expansion valve 21, it enters the indoor heat exchanger 10 to undergo heat exchange (cooling), evaporate and become a gas state, and the first connection pipe 13 via the three-way switching valve 20. Flow into.

On the other hand, the other refrigerant liquid is depressurized to a low pressure by the second electric expansion valve 23, and then flows into the gas-liquid separator 19 from the third connecting pipe 22. Here, the outdoor heat exchanger 4 merges with the refrigerant from the indoor unit 9a in the cooling operation state, and passes through the first connection pipe 13.
To the compressor 2 to form a circulation cycle in which heat is exchanged and vaporized into a gas state, and the heating main operation is performed. The flow rate of passage through the second electric expansion valve 23 is controlled so as to reach a predetermined superheat level by detecting the superheat degree of the outlet refrigerant of the outdoor heat exchanger 4.

Further, in the simultaneous cooling and heating operation mainly for cooling, the refrigerant discharged from the compressor 2 is the outdoor heat exchanger 4 as shown in FIG.
Flow into the gas-liquid separator 19 of the first connecting pipe 13 after heat exchange by an arbitrary amount into a gas-liquid two-phase high-temperature high-pressure state. Then, after being separated into gas and liquid here, they are sent to the inside of the room. The gaseous refrigerant gas separated by 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-exchanged (heating) in the indoor heat exchanger 10 to be condensed and liquefied. , The third connecting pipe 22 from the first electric expansion valve 21
Flows into.

On the other hand, the liquid liquid refrigerant separated by the gas-liquid separator 19 flows into the bypass pipe 27 and the third connection pipe 22. 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 (cooling the refrigerant in the third connection pipe 22) in the third connection pipe 22 and the heat exchange section 26 to be gasified and Flows into the connection pipe 14 of. 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 26, becomes a slightly supercooled state, and goes through the second electric expansion valve 23 to perform the heating operation. It joins the refrigerant from the indoor unit 9a in the state and flows into each indoor unit 9b, 9c in the cooling operation state. Then, the refrigerant flowing into each indoor unit 9b, 9c in the cooling operation state is depressurized to a low pressure by the first electric expansion valve 21, and is heat-exchanged (cooled) in the indoor heat exchanger 10 to be evaporated.
The refrigerant in this gas state passes through the three-way switching valve 20 to the second
A cooling cycle is performed by flowing into the connecting pipe 14 and returning to the compressor 2 again.

As described above, in the cooling / heating simultaneous operation mainly of cooling of the air conditioner of this embodiment, the heat exchange between the refrigerant flowing through the third connecting pipe 22 and the refrigerant flowing through the bypass pipe 27 causes the gas-liquid separator 19 to operate. The refrigerant liquid passing through the separated third connecting pipe 22 is in a supercooled state. Therefore, even if the path of the third connecting pipe 22 from the gas-liquid separator 19 to each of the indoor units 9a to 9c becomes long and there is a pressure loss or the like, the refrigerant will not be in 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, 9c in the cooling operation state is always in the liquid state regardless of the length of the third connection pipe 22. You can 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.

Further, in the bypass pipe 27, a capillary pipe 25 that functions as a flow rate control device whose flow resistance changes according to the gas-liquid state of the refrigerant.
Therefore, even if the refrigerant liquid level of the gas-liquid separator 19 is lowered, a large amount of the gaseous refrigerant does not flow into the bypass pipe 27. Therefore, the indoor unit 9a in the heating operation state is kept supplied with an appropriate amount of gas refrigerant, and the heating capacity is not significantly reduced.

Furthermore, since the liquid level of the refrigerant in the gas-liquid separator 19 can be maintained at a constant position by the bypass pipe 27 and the surplus refrigerant can be stored in the accumulator 8, the third connecting pipe 22
There is no need to install a receiver or the like on the way.

In the above embodiment, the three-way switching valve 20 is provided and the first connecting pipe 13 and the second connecting pipe 14 are switchably connected. However, as shown in FIG. 5, two solenoid valves 30, 31, etc. An on-off valve may be provided to switchably connect. Further, in the above embodiment, the indoor unit 9a to 9c is described as being provided with the electric expansion valve 21 which is the first flow control device, but as shown in FIG. 5, the temperature expansion valve 12, the capillary tube 32, If the indoor unit is air-cooled, the temperature expansion valve 12 is used to reduce the pressure to a low pressure, and in the case of heating, the indoor heat exchanger 10 is passed through the capillary tube 32 and the check valve 11, The refrigerant may flow into the third connecting pipe 22. Further, in the above embodiment, the second electric expansion valve 23 is provided in the third connection pipe 22, but any operation equivalent to this may be used, and as shown in FIG. It may be an on-off valve such as a flow control valve 33 (for example, a ball valve). Besides, in the above embodiment, the bypass pipe 27 is described as being branched from the substantially middle portion of the height of the gas-liquid separator 19, but the connection position of the third connection pipe 22 and the first connection pipe 13 are described. It can be arbitrarily selected as long as it is between the opening.

By the way, in each of the above-described embodiments, the indoor units 9a to 9c are described as being constituted by the three-way switching valve 20, the indoor heat exchanger 10, the first electric expansion valve 21, and the like.
Only 10 may be the indoor units 9a to 9c, and the three-way switching valve 20 and the first electric expansion valve 21 may be controlled by the air conditions of the indoor units 9a to 9c. In the above embodiment, the outdoor heat exchanger 4 and the indoor heat exchanger 10 exchange heat with air and a refrigerant. However, one of them is water and a refrigerant or both heat exchangers are water and a refrigerant. It may be heat-exchanged.

[Advantages of the Invention] As described above, the air conditioner of the present invention is
A gas-liquid separator is provided in the middle of the first connection pipe or the second connection pipe that connects the outdoor unit of the stand and the plurality of indoor units in parallel, and one of the indoor heat exchangers serves as the first connection pipe. Switchably connected to the second connection pipe, and the other of the indoor heat exchangers was provided as the third connection pipe to either the first connection pipe or the second connection pipe via the flow control device. A gas-liquid separator is connected, and the gas-liquid separator and the first connection pipe or the second connection pipe not provided with the gas-liquid separator are connected by a bypass pipe, and the bypass pipe is connected to a third connection pipe. By providing the heat exchanging section for exchanging heat between the gas-liquid separator and the flow rate controller, the cooling operation and the heating operation of the plurality of indoor units connected in parallel can be performed simultaneously or selectively. Can be performed, and moreover, the flow rate of the refrigerant and the gas-liquid state can be properly controlled. In, it is cooling and heating operations corresponding to the heating and cooling requirements of the space in which each indoor unit is installed, to expand the use range.

Further, in the cooling / heating simultaneous operation mainly for cooling, even when the third connecting pipe is long and has a large pressure loss, the refrigerant flowing through the third connecting pipe can be made into a single-phase refrigerant in a liquid state, and further, the bypass pipe can be used. Since a large amount of gas refrigerant does not flow in, the stable and efficient cooling and heating operation can be performed.

Further, only by adding the third connecting pipe for connecting the indoor units, 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.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram centering on the refrigerant system of the air conditioner of the first embodiment of the present invention, and FIG. 2 is a refrigerant circulation showing the operating state of only cooling or heating of the air conditioner of FIG. Fig. 3 is a refrigerant circulation diagram showing the operation state of the heating-based main body of the air conditioner of Fig. 1, and Fig. 4 is a refrigerant circulation diagram showing the operating state of the cooling-main body of the air conditioner of Fig. 1. FIG. 5 is an overall block diagram centering on the refrigerant system of the air conditioner of another embodiment of the present invention, and FIG. 6 is an overall block diagram centering on the refrigerant system of the 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 pipe 14: first 2 connection pipe, 19: gas-liquid separator 21: first expansion control valve that is the first flow control device 22: third connection pipe 23: second expansion valve that is the electric expansion valve 26: heat exchange Part, 27: bypass piping 33: electrical flow control valve. In the drawings, the same reference numerals and symbols indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. An outdoor unit having a compressor, a switching valve, an outdoor heat exchanger, etc., and a plurality of indoor units having an indoor heat exchanger to which a flow rate control device is connected, respectively, the outdoor unit and the indoor unit. In an air conditioner in which machines are connected in parallel via a first connection pipe and a second connection pipe, a gas-liquid separator is provided in the middle of the first connection pipe or the second connection pipe, One of a plurality of indoor units is the first
Switchable connection with the connection pipe of or the second connection pipe,
The other one is connected to a gas-liquid separation device provided in either the first connection pipe or the second connection pipe via a flow control device through a third connection pipe, and the gas-liquid separation device and the gas-liquid separation device are connected. The first connection pipe or the second connection pipe, which is not provided with the liquid separation device, is connected by a bypass pipe, and the bypass pipe is heat-exchanged between the gas-liquid separation device of the third connection pipe and the flow control device. An air conditioner comprising a heat exchange section for performing the above. 2. The air conditioner according to claim 1, wherein the bypass pipe is provided with a flow rate control device.