JP2522362B2 - 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 joins again in the connection pipe 13 and is again formed. 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, since all the indoor units 9a to 9c need to perform heating operation or cooling operation, There was a possibility that heating would be performed in a place where cooling was necessary, or cooling might be performed in a place where heating was 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 Problems] An air conditioner according to the present invention is a gas-liquid separation device in the middle of a first connection pipe or a second connection pipe that connects one outdoor unit and a plurality of indoor units. A device is provided, and one of the plurality of indoor units is switchably connected to the first connection pipe or the second connection pipe, and the other one is connected to the first connection pipe via the flow control device via the third connection pipe. It is connected to a gas-liquid separation device provided in either the first connecting pipe or the second connecting pipe.

[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, high-pressure gas is heat-exchanged by an outdoor heat exchanger in an arbitrary amount to be in a two-phase state and flow into the gas-liquid separation device from the first or second 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. On the other hand, the other liquid liquid refrigerant is introduced into the third connection pipe, merges with the refrigerant from the indoor unit in the heating operation state through the flow rate control device, 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.

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. On the other hand, the other liquid liquid refrigerant is introduced into the third connection pipe, and merges with the refrigerant from the indoor unit in the heating operation state via the receiver and the flow rate control device to each indoor unit in the cooling operation state. Inflow. 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 connecting 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 connecting pipe. Then, heat is exchanged (heated) and returns to the outdoor unit through the third connecting pipe.

In the case of only the cooling operation, the heat is exchanged (cooled) by being introduced into each indoor unit through the first connecting pipe and the third connecting pipe. Then, the heat-exchanged refrigerant returns to the outdoor unit through the second 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.
Third side connecting the side and the gas-liquid separator 19 of the first connection pipe 13
Is a receiver provided in the middle of the third connection pipe 22, and 24 is an electric expansion valve that is a second flow rate control device provided in the third connection pipe 22. 25 is a first temperature sensor provided in a pipe connecting the four-way valve 3 and the outdoor heat exchanger 4, 26
Is a second temperature sensor provided in the heat transfer tube located in the substantially middle part of the outdoor heat exchanger 4.

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.
~ 9c through the three-way switching valve 20 to flow into the indoor heat exchanger 10, after heat exchange (heating), it is condensed and liquefied. The refrigerant in the liquid state is used as the first electric expansion valve 21.
Through the third connecting pipe 22 and join to form a receiver
Inflow to 23. The refrigerant flowing into the receiver 23 is further decompressed to a low pressure by the electric expansion valve 24 which is the second flow rate control device. Then, the refrigerant depressurized to a low pressure flows through the gas-liquid separator 19 and the first connection pipe 13 into the outdoor heat exchanger 4 of the outdoor unit 1, where it exchanges heat and becomes a gas state again. It is 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 receiver 23 via the second electric expansion valve 24 in the fully opened state.
Flows into. Then, it flows into each of the indoor units 9a to 9c, and is depressurized to a low pressure by the first electric expansion valve 21, and the indoor heat exchanger 10
And is exchanged with the indoor air (cooling) to be evaporated and gasified. Then, the refrigerant in the gas state forms a circulation cycle in which the refrigerant is sucked into the compressor 2 again via the three-way switching valve 20 and the second connecting pipe 14 to perform the 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, is decompressed by the first expansion valve 21, and then the indoor heat exchanger 10
After entering, heat is exchanged (cooling), vaporizes and becomes a gas state, and flows into the first connecting pipe 13 via the three-way switching valve 20.

On the other hand, after the other refrigerant liquid flows into the receiver 23, the pressure is reduced to a low pressure by the second electric expansion valve 24, and then the third connecting pipe.
It flows from 22 to the gas-liquid separator 19. Here, the first connection pipe 13 is formed by merging with the refrigerant from the indoor unit 9a in the cooling operation state.
After that, the heating main operation is performed by forming a circulation cycle of flowing into the outdoor heat exchanger 4, being heat-exchanged and evaporated to be in a gas state and returning to the compressor 2 again. The second electric expansion valve
The passing flow rate of 24 is controlled by the first and second temperature sensors 25 and 26 provided in the outdoor heat exchanger 4 so that the degree of superheat of the refrigerant is detected and a predetermined degree of superheat is obtained.

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 is
It flows into the receiver 23 through the second electric expansion valve 24 of the third connection pipe 22. At this time, the flow rate of the refrigerant passing through the third connecting pipe 22 is determined by the signal of the liquid level detector (generally known float switch etc.) provided in the gas-liquid separator 19 so that the refrigerant liquid level in the gas-liquid separator 19 is predetermined. Is controlled to be within the range of. That is, when the liquid level is higher than the predetermined range, the opening degree of the second electric expansion valve 24 is opened, and when the liquid level is lower than the predetermined range, the second electric expansion valve 24 is opened. The opening degree of the expansion valve 24 is controlled to be closed. Therefore, it is controlled so that only the liquid refrigerant in the liquid state always flows through the third connecting pipe 22. The refrigerant from the receiver 23 merges with the refrigerant from the indoor unit 9a in the heating state, and flows from the third connecting pipe 22 into the indoor units 9b, 9c in the cooling operation state. Then, after the pressure is reduced to a low pressure state by the first electric expansion valve 21, heat is exchanged (cooled) in the indoor heat exchanger 10 and evaporated. The refrigerant in the gas state flows into the second connection pipe 14 via the three-way switching valve 20 and forms a circulation cycle in which the refrigerant returns to the compressor 2 again to perform the cooling-main operation.

In this embodiment, the receiver 23 is connected to the third connecting pipe 22.
And the electric expansion valves 21 and 24 which are the first and second flow rate control devices, and the superheat degree of the refrigerant of the outdoor heat exchanger 4 and the indoor heat exchanger 10 functioning as an evaporator or a condenser. Each supercooling degree is controlled. Therefore, in the case of only cooling or heating operation, or a change in the number of operating indoor units 9b ~ 9c in the case of simultaneous cooling and heating operation, or, the receiver 23 to adjust the fluctuation of the refrigerant amount due to changes in the air conditions. You can

Further, 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 24 is provided in the third connection pipe 22, but any operation equivalent to this may be performed, and as shown in FIG. It may be an on-off valve such as a flow control valve 33 (for example, a ball valve). In addition, in the above-described embodiment, a description has been given of the heat transfer pipe provided with the temperature sensor in the substantially middle portion of the outdoor heat exchanger 4, but the connection portion with the first connection pipe 13 of the outdoor heat exchanger 4 may also be used. In addition, the temperature sensor is connected from the four-way valve 3 to the first connection pipe of the outdoor heat exchanger 4.
You may install in the pipe line which goes to 13 connection parts.

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
One of the indoor heat exchangers in which a gas-liquid separation device is provided in the middle of the first connection pipe or the second connection pipe that connects the outdoor unit of one unit and the plurality of indoor units in parallel, and each of which is connected to the flow rate control unit Is connected to the first connection pipe and the second connection pipe in a switchable manner, and the other of the indoor heat exchangers is connected to the third connection pipe via the flow control device to form the first connection pipe or the second connection pipe. By connecting to the gas-liquid separation device provided in either of the piping,
Since the cooling operation and the heating operation of each of the plurality of indoor units connected in parallel can be performed simultaneously or selectively, and moreover, the flow rate of the refrigerant and the gas-liquid state can be appropriately controlled,
Cooling and heating operations that meet the cooling and heating requirements of the space where each indoor unit is installed can be performed, expanding the range of use.

Further, by simply 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 device that is an electric expansion valve 22: third connection pipe, 23: receiver 24: second expansion device that is an electric expansion valve 33: Electric flow control valve. In the drawings, the same reference numerals and symbols indicate the same or corresponding parts.

Claims (1)

(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
Connectable to the connection pipe of or the second connection pipe,
An air conditioner characterized in that 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.