JP2875507B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room heat pump type air conditioner in which a plurality of indoor units are connected to one heat source unit. The present invention relates to an air conditioner capable of simultaneously performing cooling in the unit and heating in the other indoor unit, particularly to a refrigerant flow controller.

[0002]

2. Description of the Related Art FIG. 10 is an overall configuration diagram mainly showing a refrigerant system of a conventional air conditioner. In the figure, A is a heat source unit, and B, C and D are indoor units connected in parallel with each other as described later, and have the same configuration. E is a first branch, a second flow controller, a second branch, a gas-liquid separator, a heat exchanger, a third flow controller,
It is a repeater incorporating a fourth flow control device. 1 is a compressor, 2 is a 4-way valve, 3 is a heat source unit side heat exchanger, 4 is an accumulator, 5 is an indoor side heat exchanger, 6 is a first connection pipe, 7
Is a second connection pipe. Reference numeral 20 denotes a heat source unit-side blower that blows air to the heat source unit-side heat exchanger 3 and has a variable air volume.
c and 6d respectively connect the indoor-side heat exchangers 5 of the indoor units B, C and D to the relay unit E, and correspond to the first connection pipes 6 corresponding to the first connection pipes on the indoor unit side, 7b, 7c, 7d respectively connects the indoor heat exchangers 5 of B, C and D and the relay device E via the first flow control device 9, and the second indoor unit side corresponding to the second connection pipe 7 Connection piping.

[0003] Reference numeral 8 denotes first connection pipes 6b and 6 on the indoor unit side.
c, 6d and the first connection pipe 6 or the second connection pipe 7
This is a three-way switching valve that is switchably connected to the side. Reference numeral 9 denotes a first flow control device which is connected in proximity to the indoor heat exchanger 5 and is controlled by the amount of superheat at the outlet side of the indoor heat exchanger 5 during cooling and by the subcool amount during heating. It is connected to the second connection pipes 7b, 7c, 7d on the indoor unit side. 1
Reference numeral 0 denotes a first branch portion including a first connection pipe 6b, 6c, 6d on the indoor unit side, and a three-way switching valve 8 switchably connected to the first connection pipe 6 or the second connection pipe 7. is there.
Reference numeral 11 denotes a second branch portion including the second connection pipes 7b, 7c, and 7d on the indoor unit side and the second connection pipe 7.

[0004] Reference numeral 12 denotes a gas-liquid separator provided in the middle of the second connection pipe 7, the gas layer portion of which is connected to the first port 8 a of the three-way switching valve 8, and the liquid layer portion thereof is connected to the second branch. It is connected to the unit 11. 13 is a gas-liquid separator 12 and a second branch 1
A second flow control device (here, an electric expansion valve) that can be opened and closed is connected to the first flow control device. 14 is the second branch 11
A bypass pipe connecting the first connection pipe 6 and the first connection pipe 6, a third flow control device (here, an electric expansion valve) 15 provided in the middle of the bypass pipe 14, and a bypass pipe 14 a
Are provided downstream of the third flow control device 15 provided in the middle of the second branch 11, and heat is generated between the second branch 11 and the associated portion of the second connection pipes 7 b, 7 c, and 7 d on the indoor unit side. This is a second heat exchange unit that performs exchange. 16b, 16c, 1
6 d is provided downstream of the third flow control device 15 provided in the middle of the bypass pipe 14, respectively, and the second connection pipes 7 b, 7 c on the indoor unit side in the second branch section 11 are provided.
This is a third heat exchange section that performs heat exchange with each of the heat exchange units 7d. 19 is the third flow control device 15 of the bypass pipe 14
Downstream of the second heat exchange section 16a and
A first heat exchange section 17 for exchanging heat between a pipe connecting the gas-liquid separation device 12 and the second flow control device 13 is provided between the second branch section 11 and the first connection pipe 6. Openable and closable fourth flow control device (here, electric expansion valve) connected between
It is.

[0005] On the other hand, reference numeral 32 denotes a third check valve provided between the heat source unit side heat exchanger 3 and the second connection pipe 7, and a third check valve 32 extending from the heat source unit side heat exchanger 3 to the second connection pipe. Only the refrigerant flow to 7 is allowed. Reference numeral 33 denotes a fourth check valve provided between the four-way valve 2 of the heat source device A and the first connection pipe 6, and allows a refrigerant to flow only from the first connection pipe 6 to the four-way valve 2. . Reference numeral 34 denotes a fifth check valve provided between the four-way valve 2 of the heat source unit A and the second connection pipe 7, and a fifth check valve 34 extending from the four-way valve 2 to the second connection pipe 7.
Only the refrigerant flow is allowed. Reference numeral 35 denotes a sixth check valve provided between the heat source unit-side exchanger 3 and the first connection pipe 6, and allows the refrigerant to flow only from the first connection pipe 6 to the heat source unit-side exchanger 3. I do. Third, fourth, fifth and sixth check valves 3
The flow path switching device 40 is composed of 2, 33, 34 and 35.
Reference numeral 21 denotes a take-out pipe having one end connected to the liquid outlet pipe of the heat source unit side heat exchanger 3 and the other end connected to the inlet pipe of the accumulator 4, 22 denotes a throttle device provided in the middle of the take-out pipe 21, and 23 denotes The second temperature detecting means is provided between the expansion device 22 and the inlet pipe of the accumulator 4 of the take-out pipe 21.

[0006] Since the conventional air conditioner capable of simultaneous operation of cooling and heating is configured as follows, in the case of only cooling operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2 and passes through the heat source unit. After the heat exchange with the air blown by the heat-source-side blower 20 having a variable airflow in the side heat exchanger 3 and condensing and liquefying, the third check valve 32, the second connection pipe 7, the gas-liquid separator 12, in the order of the second flow control device 13,
Further, the second branch portion 11 and the second connection pipe 7 on the indoor unit side
b, 7c, and 7d, and flows into each of the indoor units B, C, and D.

[0007] The refrigerant flowing into each of the indoor units B, C, D is decompressed to a low pressure by the first flow control device 9 controlled by the amount of superheat at the outlet of each of the indoor heat exchangers 5, and the indoor heat is removed. The exchanger 5 exchanges heat with room air to evaporate and gasify, thereby cooling the room. The refrigerant in this gas state is supplied to the first connection pipes 6b, 6c, 6d on the indoor unit side, the three-way switching valve 8, the first branch portion 10, the first connection pipe 6, and the fourth check valve 33. A circulation cycle is drawn through the four-way valve 2 of the heat source unit and the compressor 1 through the accumulator 4 to perform the cooling operation. At this time, the first port 8a of the three-way switching valve 8 is closed,
The port 8b and the third port 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure, the first connection pipe 6 necessarily flows to the third check valve 32 and the fourth check valve 33.
At the time of this cycle, part of the refrigerant that has passed through the second flow control device 13 enters the bypass pipe 14 and is reduced to a low pressure by the third flow control device 15 so that the third heat exchange section 16
After heat exchange between the second connection pipes 7b, 7c and 7d on the indoor unit side of the second branch section 11 at b, 16c and 16d, the second branch section is formed at the second heat exchange section 16a. 11 exchanges heat with the associated portions of the second connection pipes 7b, 7c, 7d on the indoor unit side, and further exchanges the refrigerant with the refrigerant flowing into the second flow control device 13 in the first heat exchange unit 19. The refrigerant that has undergone heat exchange between the refrigerants enters the first connection pipe 6 and the fourth check valve 33, and is drawn into the compressor 1 via the four-way valve 2 and the accumulator 4 of the heat source unit.

On the other hand, the first, second, and third heat exchange units 19,
Heat is exchanged at 16a, 16b, 16c, 16d and cooled,
The refrigerant in the second branch portion 11, which is sufficiently subcooled, flows into the indoor units B, C, and D to be cooled.

In the case of cooling mainly in the simultaneous cooling and heating operation, the refrigerant gas discharged from the compressor 1 flows into the heat source unit side heat exchanger 3 through the four-way valve 2 and the heat source having a variable air flow rate. It exchanges heat with the air blown by the machine-side blower 20, and enters a gas-liquid two-phase high-temperature high-pressure state. Here, the blowing amount of the heat source side blower 20 and the capacity of the compressor 1 are adjusted so that the pressure obtained from the saturation temperature detected by the second temperature detecting means 23 becomes a predetermined target pressure. Then, the gas-liquid two-phase high-temperature and high-pressure refrigerant becomes the third refrigerant.
Through the check valve 32 and the second connection pipe 7 to the gas-liquid separator 12 of the repeater E. Here, the gaseous refrigerant and the liquid refrigerant are separated, and the separated gaseous refrigerant is heated in the order of the first branch portion 10, the three-way switching valve 8, and the first connection pipe 6d on the indoor unit side. It flows into the indoor unit D, exchanges heat with the indoor air in the indoor heat exchanger 5 to condense and liquefy, and heats the room.

Further, the air is controlled by the subcool amount at the outlet of the indoor heat exchanger 5, passes through the first flow control device 9 which is almost fully opened, and is slightly reduced in pressure, and flows into the second branch portion 11. On the other hand, the remaining liquid refrigerant passes through the second flow control device 13 and flows into the second branch portion 11, where it joins with the refrigerant that has passed through the indoor unit D to be heated, and
Flows into the indoor units B and C through the connection pipes 7b and 7c. The refrigerant flowing into each of the indoor units B and C is controlled by the first superheat amount at the outlet of the indoor heat exchangers B and C.
Is reduced to a low pressure, exchanges heat with room air, evaporates, is gasified, and cools the room.
Further, the refrigerant in the gas state is supplied to the first connection pipes 6b and 6c on the indoor unit side, the three-way switching valve 8, the first branch 10
Through the first connection pipe 6, the fourth check valve 33, the four-way valve 2 of the heat source unit, and the accumulator 4, the circulation cycle is drawn into the compressor 1, and the cooling-main operation is performed.

[0011]

Since the conventional air conditioner is configured as described above, the cooling load in the room when only the cooling operation is performed, and the cooling load in the room when the cooling main operation is performed. When the heating load fluctuates, the pressure of the refrigerant cycle changes, which causes disturbance of the refrigerant cycle, or the disturbance of the refrigerant cycle makes it impossible to stably detect the low-pressure saturation temperature in the heat source unit, or in the case of mainly cooling operation. The refrigerant that has passed through the heat source unit side heat exchanger becomes a gas-liquid two-phase state, causing problems such as a failure to stably detect the saturation temperature of the refrigerant. There has been a problem that the indoor unit cannot perform cooling while the other indoor unit cannot simultaneously perform heating.

In particular, when installed in a large-scale building, an office automation (OA) such as an interior unit and a perimeter unit, or a general office room and a computer room.
Because the air conditioning load is significantly different from the converted rooms,
It was a particular problem.

The present invention has been made in order to solve such a problem, and selectively performs cooling and heating for each indoor unit.
It is another object of the present invention to provide an air conditioner capable of simultaneous cooling and heating operation in which one indoor unit can perform cooling and the other indoor unit can perform heating simultaneously and stably.

[0014]

SUMMARY OF THE INVENTION The air conditioner according to this inventions are the compressor, the one having a four-way valve and the heat source unit side heat exchanger and the heat source apparatus, the indoor-side heat exchanger and the first A plurality of indoor units having a flow control device are connected by piping, and in an air conditioner that performs cooling and heating operation by supplying a refrigerant from the heat source unit to the plurality of indoor units, the heat source unit-side heat exchanger includes at least a
The first and second heat exchange elements,
And the second heat exchange element is connected to the refrigerant inlet of the heat source unit side heat exchanger.
A third flow path connected in parallel with the first flow path;
Of the first and second heat exchange elements
A second flow path connected to the first flow path in a row and heat
Connected to the liquid outlet pipe of the heat exchanger on the source unit side
With the first flow path bypassing the third heat exchange element
The heat source unit connected to the liquid outlet piping of the heat exchanger
A bypass pipe is provided, and the first flow path is connected to the third heat exchange element.
Or selectively switch to the heat source unit side bypass pipe side
It is provided with a switching device .

[0015]

[0016]

Further, the first and second connection pipe connecting the heat source unit and a plurality of indoor units, switchably one of a plurality of indoor units to the first connection pipe or the second connecting pipe A first branch having a valve device to be connected, and a second branch connected to the other of the indoor heat exchangers of the plurality of indoor units via a first flow control device, and via a second flow control device; And a second branch portion connected to the second connection pipe, and the liquid outflow side pipe of the heat source device side heat exchanger is connected to the second connection pipe.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 1 of the present invention.
FIGS. 2 to 4 show operation states during the cooling / heating operation in the first embodiment of FIG. 1, FIG. 2 is an operation state diagram of only the cooling or heating operation, and FIGS. FIG. 3 shows the main operation of heating (when the heating operation capacity is larger than the cooling operation capacity), and FIG. 4 shows the main operation of cooling (when the cooling operation capacity is larger than the heating operation capacity).
FIG. The first embodiment
In the following, a case where three indoor units are connected to one heat source unit will be described, but the same applies to a case where two or more indoor units are connected.

In FIG. 1, A is a heat source unit, and B, C and D are indoor units connected in parallel to each other as described later, and have the same configuration. E incorporates a first branch, a second flow controller, a second branch, a gas-liquid separator, a heat exchanger, a third flow controller, and a fourth flow controller as described later. It is a repeater. Further, 1 is a compressor, 2 is a four-way valve for switching the refrigerant flow direction of the heat source unit, 3 is a heat source side heat exchanger, 4 is an accumulator connected to the compressor 1 via the four-way valve 2, 20 Reference numeral denotes a heat-source-unit-side blower that blows air to the heat-source-unit-side heat exchanger 3, and has a compressor 1, a four-way valve 2, a heat-source-unit-side heat exchanger 3, and an accumulator 4.
The heat source device A is constituted by the heat source device-side blower 20. Reference numeral 5 denotes an indoor heat exchanger provided in the three indoor units B, C, and D; 6, a thick first connection pipe for connecting the four-way valve 2 of the heat source unit A and the relay unit E; 6c and 6d connect the indoor side heat exchangers 5 of the indoor units B, C and D to the relay unit E, respectively, and the first connection pipe on the indoor unit side corresponding to the first connection pipe 6; This is a second connection pipe that is thinner than the first connection pipe 6 that connects the heat source device side heat exchanger 3 of A and the relay machine E. 7b, 7c, 7d are indoor units B,
A second connection pipe on the indoor unit side corresponding to the second connection pipe 7 that connects the indoor heat exchangers 5 of C and D and the relay unit E. 8 is the first connection pipe 6b, 6c, 6d on the indoor unit side
To the first connection pipe 6 or the second connection pipe 7 so as to be switchable, and to the first connection pipe 6 on the indoor unit side.
b, 6c, 6d, the first connection pipe 6, the second connection pipe 7
Are three-way switching valves as valve devices capable of closing the flow.

Reference numeral 9 is connected in proximity to the indoor side heat exchanger 5, and is based on the amount of superheat at the outlet side of the indoor side heat exchanger 5 during cooling, and the amount of subcooling at the outlet side of the indoor side heat exchanger 5 during heating. Is connected to the second connection pipes 7b, 7c, 7d on the indoor unit side. 1
Reference numeral 0 denotes a first branch portion including a first connection pipe 6b, 6c, 6d on the indoor unit side and a three-way switching valve 8 that is switchably connected to the first connection pipe 6 or the second connection pipe 7. is there. 11 is a second connection pipe 7b, 7c, 7d on the indoor unit side
And a second branch portion composed of a second connection pipe 7. 12
Is a gas-liquid separation device provided in the middle of the second connection pipe 7, the gas phase portion is connected to the first port 8 a of the three-way switching valve 8, and the liquid phase portion is connected to the second branch portion 11. Have been.
Reference numeral 13 denotes an openable and closable second flow control device (here, an electric expansion valve) connected between the gas-liquid separation device 12 and the second branch portion 11.

Reference numeral 14 denotes a bypass pipe connecting the second branch portion 11 and the first connection pipe 6, reference numeral 15 denotes a third flow control device (here, an electric expansion valve) provided in the middle of the bypass pipe 14, 16 a is provided downstream of the third flow control device 15 provided in the middle of the bypass pipe 14, and the second connection pipes 7 b, 7 on the side of each indoor unit in the second branch 11.
This is a second heat exchange section that performs heat exchange with the meeting sections c and 7d. 16b, 16c, 16d are provided downstream of the third flow control device 15 provided in the middle of the bypass pipe 14, respectively, and the second connection pipes 7b, 7c, This is a third heat exchange section that performs heat exchange with each of the heat exchange units 7d.

Reference numeral 18 denotes fourth pressure means which connects the compressor 1 and the four-way valve 2 and is provided in the middle of a pipe which always has a high pressure. 19 is the third flow control device 15 of the bypass pipe 14
Downstream of the second heat exchange section 16a and
A first heat exchange section 17 for exchanging heat between a pipe connecting the gas-liquid separation device 12 and the second flow control device 13 is provided between the second branch section 11 and the first connection pipe 6. Openable and closable fourth flow control device (here, electric expansion valve) connected between
It is. On the other hand, reference numeral 32 denotes a third check valve provided between the heat source unit side heat exchanger 3 and the second connection pipe 7, and is provided only from the heat source unit side heat exchanger 3 to the second connection pipe 7. Allow refrigerant flow. Reference numeral 33 denotes the four-way valve 2 of the heat source unit A and the first connection pipe 6
Between the first connection pipe 6 and the four-way valve 2 only.

Reference numeral 34 denotes a fifth check valve provided between the four-way valve 2 of the heat source unit A and the second connection pipe 7, and a fifth check valve 34 is provided.
To the second connection pipe 7 only. 35
Is a sixth check valve provided between the heat source unit side heat exchanger 3 and the first connection pipe 6, and allows the refrigerant to flow only from the first connection pipe 6 to the heat source unit side heat exchanger 3. Allow. The third, fourth, fifth, and sixth check valves 32, 33, 34, and 35 constitute a flow path switching device 40. Reference numeral 21 denotes one end connected to the liquid-side outflow portion of the heat source unit-side heat exchanger 3, and the heat source unit-side heat exchanger 3
A take-out pipe, which is perpendicular to the fin portion of the accumulator 4 and has the other end connected to the inlet of the accumulator 4, 22 is a throttle device provided in the middle of the take-out pipe 21, 23 is a throttle device 22, It is a second temperature detecting means provided between the connecting part.

Next, the operation of the first embodiment will be described. First, the case of only the cooling operation will be described with reference to FIG. As shown by a solid line arrow in the figure, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, and is blown by the heat-source-unit-side blower 20 having a variable air-volume in the heat-source-unit heat exchanger 3. After the heat exchange with the condensed liquid, the third check valve 32, the second connection pipe 7, the gas-liquid separator 1
2, in the order of the second flow control device 13, and further the second branch portion 11, the second connection pipes 7b, 7c, 7 on the indoor unit side.
and d flows into each of the indoor units B, C, and D. The refrigerant flowing into each of the indoor units B, C, and D is decompressed to a low pressure by the first flow control device 9 controlled by the amount of superheat at the outlet of each of the indoor heat exchangers 5, and the indoor heat exchanger 5 The heat exchanges with the indoor air to evaporate and gasify and cool the room.

The refrigerant in this gas state is supplied to the first connection pipes 6b, 6c, 6d on the indoor unit side, the three-way switching valve 8,
, The first connection pipe 6, the fourth check valve 33,
A circulation cycle is drawn through the compressor 1 through the four-way valve 2 and the accumulator 4 of the heat source unit, and performs a cooling operation. At this time, the first port 8a of the three-way switching valve 8 is closed, and the second port 8b and the third port 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure,
Flow through the check valve 32 and the fourth check valve 33.

In this cycle, a part of the refrigerant that has passed through the second flow control device 13 enters the bypass pipe 14 and is reduced to a low pressure by the third flow control device 15 so that the third heat exchange portion 16b , 16c, and 16d, heat exchange is performed between the second connection pipes 7b, 7c, and 7d on the indoor unit side of the second branch section 11 and the second branch section 1 is formed by the second heat exchange section 16a.
1 exchanges heat with the junction of the second connection pipes 7b, 7c, 7d on the side of each indoor unit, and furthermore, the first heat exchange section 19
Performs heat exchange with the refrigerant flowing into the second flow control device 13, and the evaporated refrigerant enters the first connection pipe 6 and the fourth check valve 33, and enters the four-way valve 2 of the heat source device. , And is sucked into the compressor 1 through the accumulator 4. On the other hand, the first, second, and third heat exchange units 19, 16a, 16b, 16c, and 16d exchange heat and are cooled, and the second subcooler is sufficiently provided.
The refrigerant in the branch unit 11 of the indoor unit B to be cooled is
Flow into C and D.

Next, the case of only the heating operation will be described with reference to FIG. That is, as shown by a dotted arrow in the figure, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, passes through the fifth check valve 34, the first connection pipe 7, the gas-liquid separation After passing through the device 12, the first branch portion 10, the three-way switching valve 8, and the first connection pipes 6b, 6c, 6d on the indoor unit side flow into the indoor units B, C, D in order, and the indoor air and Heat exchange to condense and liquefy and heat the room.

The refrigerant in the liquid state is controlled by the subcooling amount at the outlet of each indoor heat exchanger 5 and passes through the first flow control device 9 which is almost fully open, and the second connection on the indoor unit side The gas flows into the second branch portion 11 from the pipes 7b, 7c, and 7d, merges, and further passes through the fourth flow control device 17. Here, the pressure is reduced to a low-pressure gas-liquid two-phase state by one of the first flow control device 9 and the third and fourth flow control devices 15 and 17. The refrigerant decompressed to a low pressure flows through the first connection pipe 6 into the sixth check valve 35 of the heat source unit A and the heat exchange unit 3 on the heat source unit side. The refrigerant, which has exchanged heat with the air blown by the air and evaporated to a gaseous state, constitutes a circulation cycle that is sucked into the compressor 1 through the four-way valve 2 and the accumulator 4 of the heat source unit,
Perform heating operation. At this time, the three-way switching valve 8 has the second port 8b closed, and the first port 8a and the third port 8c open. At this time, the first connection pipe 6 is on the low pressure side and the second connection pipe 7 is on the high pressure side at this time.
5 and the fifth check valve 34, it is inevitably connected to the fifth check valve 34 and the sixth check valve 35 to communicate with the suction side of the compressor 1 and the discharge side of the compressor 1. Distribute.

Next, a description will be given of a case of mainly heating in the simultaneous cooling and heating operation with reference to FIG. Here, the case where two indoor units B and C are going to heat and one indoor unit D is going to cool will be described. The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is sent to the relay E through the four-way valve 2 through the fifth check valve 34 and the second connection pipe 7 as indicated by a dotted arrow in FIG. The first branch 10, the three-way switching valve 8, and the first connection pipe 6 on the indoor unit side pass through the gas-liquid separation device 12.
b, 6c, in order of heating, each indoor unit B, C to be heated
And heat exchanges with the indoor air in the indoor heat exchanger 5 to condense and liquefy and heat the room.

The condensed and liquefied refrigerant is controlled by the amount of subcooling at the outlet of each indoor heat exchanger 5 of the indoor units B and C, and is slightly reduced in pressure through the first flow control device 9 which is almost fully open. 2 flows into the second branch portion 11. Part of the refrigerant passes through the second connection pipe 7d on the indoor unit side, enters the indoor unit D to be cooled, and is controlled by the amount of superheat at the outlet of the indoor heat exchanger 5 of the indoor unit D. After entering the first flow control device 9 and being depressurized, it enters the indoor heat exchanger 5 to exchange heat and evaporate into a gaseous state to cool the room and to switch three-way through the first connection pipe 6d. It flows into the first connection pipe 6 via the valve 8.

On the other hand, the other refrigerant is the fourth flow control device 1
7, through the thick first connection pipe 6 to join with the refrigerant that has passed through the indoor unit D to be cooled,
Flows into the heat source unit side heat exchanger 3 where it exchanges heat with the air blown by the heat source unit side blower 20 having a variable air volume and evaporates to a gas state.

This refrigerant constitutes a circulation cycle which is drawn into the compressor 1 through the four-way valve 2 and the accumulator 4 of the heat source unit, and performs a heating-main operation. At this time, the difference between the evaporation pressure of the indoor side heat exchanger 5 of the indoor unit D to be cooled and the pressure of the heat source unit side heat exchanger 3 is reduced due to the switching to the thick first connection pipe 6. At this time, the second port 8b of the three-way switching valve 8 connected to the indoor units B and C is closed, and the first port 8a and the third port 8c are closed.
Is open, the first port 8a of the indoor unit D is closed,
The opening 8b and the third opening 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure at this time, the fifth check valve 34 and the sixth check valve 35 are inevitable.
Distribute to

At the time of this cycle, a part of the liquid refrigerant enters the bypass pipe 14 from the junction of the second connection pipes 7b and 7c on the indoor unit side of the second branch section 11, and enters the third flow control device. The pressure is reduced to a low pressure at 15 and the third heat exchange section 16b,
At 16c and 16d, the second branch unit 11 on the side of each indoor unit
After heat exchange with the connection pipes 7b, 7c, 7d of the second branch pipe 11, the second heat exchange section 16a joins the second connection pipes 7b, 7c, 7d on the indoor unit side. Heat exchange with the refrigerant flowing into the second flow control device 13 in the first heat exchange unit 19, and the evaporated refrigerant passes through the first connection pipe 6, 6 and is sucked into the compressor 1 through the four-way valve 2 and the accumulator 4 of the heat source unit. On the other hand, the second and third heat exchange sections 16a, 16
Heat is exchanged in b, 16c, and 16d, and the refrigerant in the second branch portion 11, which has been cooled and sufficiently cooled, flows into the indoor unit D to be cooled.

Next, a description will be given of a case where cooling is mainly performed in the simultaneous cooling and heating operation with reference to FIG. Here, a case will be described in which two indoor units B and C are going to cool and one indoor unit D is going to heat. As shown by solid arrows in the figure, the refrigerant gas discharged from the compressor 1 flows into the heat source unit side heat exchanger 3 through the four-way valve 2, where it is changed by the heat source unit side It exchanges heat with the air to be blown, and becomes a two-phase high-temperature high-pressure state. Thereafter, the two-phase high-temperature high-pressure refrigerant is sent to the gas-liquid separator 12 of the relay E via the third check valve 32 and the second connection pipe 7. Here, the gaseous refrigerant is separated into the gaseous refrigerant and the liquid refrigerant, and the separated gaseous refrigerant is heated in the order of the first branch portion 10, the three-way switching valve 8, and the first connection pipe 6d on the indoor unit side. It flows into the indoor unit D, exchanges heat with the indoor air in the indoor heat exchanger 5 to condense and liquefy, and heats the room. Further, the pressure is controlled by the subcool amount at the outlet of the indoor side heat exchanger 5, passes through the first flow control device 9 which is almost fully opened, and is slightly reduced in pressure.
It flows into the second branch 11.

On the other hand, the remaining liquid refrigerant passes through the second flow control device 13 and flows into the second branch portion 11, where it joins with the refrigerant that has passed through the indoor unit D to be heated. Of the indoor units B and C in the order of the second connection pipes 7b and 7c.
Flows into. The refrigerant flowing into each of the indoor units B and C is reduced to a low pressure by the first flow control device 9 controlled by the superheat amount at the outlet of the indoor unit side heat exchanger 5,
It exchanges heat with indoor air, evaporates and gasifies, and cools the room. Further, the refrigerant in the gas state passes through the first connection pipes 6b and 6c, the three-way switching valve 8, and the first connection pipe 10 on the indoor unit side, passes through the first connection pipe 6, and the fourth check valve. 3
3. A circulation cycle is drawn into the compressor 1 via the four-way valve 2 of the heat source unit and the accumulator 4, and the cooling-main operation is performed.

At this time, the first port 8a of the three-way switching valve 8 connected to the indoor units B and C is closed and the second port 8b and the third port 8c are open. The mouth 8b is closed,
The first port 8a and the third port 8c are open. At this time, the refrigerant naturally flows to the third check valve 32 and the fourth check valve 33 because the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure. In this cycle, a part of the liquid refrigerant is supplied to the second connection pipes 7b, 7c, 7 on the indoor unit side of the second branch portion 11.
d enters the bypass pipe 14 from the junction, and is reduced to a low pressure by the third flow control device 15,
b, 16c, and 16d, heat exchange is performed between the second connection pipes 7b, 7c, and 7d on the indoor unit side of the second branch section 11 and the second branch section is formed by the second heat exchange section 16a. 11 exchanges heat with the associated portion of the second connection pipes 7b and 7c on the indoor unit side, and further exchanges the refrigerant with the refrigerant flowing into the second flow control device 13 at the first heat exchange portion 19. The evaporative refrigerant enters the first connection pipe 6, the fourth check valve 33, and is sucked into the compressor 1 via the four-way valve 2 of the heat source unit and the accumulator 4. On the other hand, the first, second and third heat exchange units 19 and 16
The refrigerant in the second branch portion 11, which has been cooled by the heat exchange at a, 16b, 16c, and 16d and has a sufficient subcool, flows into the indoor units B and C to be cooled.

In the cooling-only operation and the cooling-main operation in the first embodiment, the compressor 1
Is controlled so that the temperature detected by the second temperature detecting means 23 becomes a predetermined value, and discharges a high-temperature and high-pressure refrigerant gas. A part of the gas-liquid two-phase refrigerant flowing out of the liquid-side outflow pipe of the heat source unit-side heat exchanger 3 passes through the extraction pipe 21 and is orthogonal to the fin tube of the heat source unit-side heat exchanger 3. When passing through the region, the air exchanges with the air supplied by the heat source unit-side blower 20 and becomes a liquid refrigerant alone, flows into the expansion device 22, is reduced to a low pressure, and flows into the accumulator 4. On the other hand, in the operation only for heating and the operation mainly for heating, the compressor 1 is connected to the fourth pressure detecting means 18.
Is controlled so that the detected pressure becomes a predetermined value, and high-temperature and high-pressure refrigerant gas is discharged.

As described above, according to the first embodiment, one end is connected to the liquid outlet side pipe of the heat source unit side heat exchanger 3 and is orthogonal to the fin portion of the heat source unit side heat exchanger 3. And a second temperature detecting means 23 between the expansion device 22 of the take-out tube 21 and the inlet tube of the accumulator 4. Therefore, even if the two-layer gas-liquid refrigerant is sent out from the heat source unit side heat exchanger 3 depending on the air volume control condition of the heat source unit side blower 20, or if the outside air temperature is high and the refrigerant evaporates, non-condensable refrigerant is generated, When the refrigerant passing through the extraction pipe 21 passes through the area of the extraction pipe 21 orthogonal to the fin portion of the heat source unit side heat exchanger 3, the refrigerant exchanges heat again to be condensed and liquefied to become a complete liquid refrigerant. Thus, the stable temperature of the low-pressure-side saturated refrigerant can always be accurately detected by the second temperature detecting means 23. As a result, it is possible to obtain an air conditioner capable of simultaneous cooling and heating that can selectively perform cooling and heating for each indoor unit, and perform cooling and stabilization simultaneously in one indoor unit and heating in the other indoor unit. it can.

Embodiment 2 FIG. 5 is an overall configuration diagram centered on a refrigerant system of an air conditioner according to Embodiment 2 of the present invention. In Embodiment 2, the heat source unit side heat exchanger 3
And a heat source device side bypass pipe 42 that bypasses the heat exchanger 3.
And the first and second electromagnetic on-off valves 43 and 44 provided at the refrigerant inlet / outlet of the heat source unit-side heat exchanger 3 and the third electromagnetic on-off valve 45 provided in the middle of the bypass pipe 42. This constitutes the heat exchange section 3a.

Next, the heat blower 20, the first, second, and third solenoid on-off valves 43, 44,
The control of No. 45 will be described. In the second embodiment, the heat-source-unit-side heat exchange unit 3a includes the heat-source-unit-side heat exchanger 3 and the heat-source-unit-side bypass pipe 42, and first, second, and third electromagnetic on-off valves 43, 44, and 45. When the indoor cooling load is large, a large heat source side heat exchange capacity is obtained, and when the indoor cooling load is small, a small heat source side heat exchange capacity is obtained. Are equal, the heat source unit side heat exchanger capacity can be adjusted in three stages to eliminate the need for the heat source unit side heat exchange capacity. First
The stage corresponds to a case where the largest heat source unit side heat exchange capacity is required. By opening the first and second solenoid on-off valves 43 and 44 and closing the third solenoid on-off valve 45, The refrigerant is circulated through the heat source unit-side heat exchanger 3 and the refrigerant is not circulated through the heat source unit-side bypass passage 42. Even when the ambient temperature of the heat source unit A is high and the refrigerant flowing into the extraction tube 21 evaporates and becomes a gaseous refrigerant, the extraction tube 21 is connected to the heat source unit side heat exchanger 3.
Since the fins are orthogonal to each other, the refrigerant and the air exchange heat, and the completely condensed and liquefied refrigerant can flow into the expansion device 22 to reduce the pressure to a low pressure.
Thus, the low-pressure saturation temperature can be detected.

The second stage corresponds to the case where the next largest heat exchange capacity on the heat source unit side is required. The first, second and third solenoid on-off valves 43, 44 and 45 are opened, and the heat source unit side is opened. Heat exchanger 3,
The refrigerant is circulated through both of the heat source unit side bypass passages 42 to adjust the amount of air blown by the heat source unit side blower 20. At this time, the range of adjusting the amount of air blown by the heat source unit-side blower 20 is from the full speed operation of the fan to the set minimum air amount. Even when the gas flows into the take-out pipe 21 as a gas-liquid two-phase refrigerant, the take-out pipe 21 is inserted into the fin portion of the heat source unit side heat exchanger 3 to exchange heat with the air and condense into a liquid. The refrigerant that has flowed into the expansion device 22 can be reduced in pressure to a low pressure, and the second temperature detector 23 can detect a low-pressure saturation temperature.

The third stage corresponds to the case where the smallest heat source side heat exchange amount is required, and the first and second solenoid on-off valves 43,
By closing the valve 44 and opening the third solenoid on-off valve 45, the refrigerant flows through the heat source unit side bypass passage 42 and does not flow through the heat source unit side heat exchanger 3. The amount of heat exchange in the exchange unit 3 is completely eliminated. At this time, the amount of air blown from the heat source unit-side blower 20 is set to the minimum air amount, and even when the gas refrigerant flowing through the heat source unit-side bypass passage 42 flows into the extraction tube 21, the extraction tube 21 is connected to the heat source unit-side heat exchange unit. Since the refrigerant is orthogonal to the fins of the device 3, the refrigerant exchanges heat with air, and the condensed and liquid refrigerant flows into the expansion device 22 and can be reduced in pressure to a low pressure. The saturation temperature can be detected.

FIG. 6 shows the blower 20, the first, second, and third solenoid on-off valves 43, 44,
It is a flowchart shown about control of 45. In step 166, it is determined whether the heat source device side heat exchange amount is to be increased or not to be increased. If it is to be increased, the process proceeds to step 167. If not, to step 168. In step 167, it is determined whether the heat source side blower 20 is at full speed or not at full speed. If it is at full speed, the process proceeds to step 170, and if not, the process proceeds to step 169. Step 16
In step 9, the air blowing amount is increased, and the process returns to step 166. In step 170, it is determined whether the first and second electromagnetic on-off valves 43 and 44 are open or closed.
The process proceeds to step 171 if the valve is closed. In step 171, the first and second solenoid valves 43 and 44 are opened, and the process returns to step 166. In step 172, the third
It is determined whether the electromagnetic on-off valve 45 is open or closed. If the valve is open, the process proceeds to step 173;
Return to 6. In step 173, the third electromagnetic switching valve 45 is closed, and the process returns to step 166.

On the other hand, in step 168, it is determined whether or not the amount of heat exchange on the heat source unit side is to be decreased or not decreased. If it is determined that the amount of heat exchange is to be decreased, the process proceeds to step 174. In step 174, it is determined whether the heat source unit-side blower 20 has the set minimum air volume or is not the minimum air volume.
The process proceeds to step S6, and if not the minimum air flow, the process proceeds to step S175. In step 175, the amount of air is reduced, and the process returns to step 166. In step 176, it is determined whether the third solenoid on-off valve 45 is open or closed. If it is open, the process proceeds to step 178, and if it is closed, the process proceeds to step 177. In step 177, the third electromagnetic switching valve 45 is opened, and the process returns to step 166. In step 178, it is determined whether the first and second electromagnetic on-off valves 43 and 44 are open or closed. If the valves are open, the process proceeds to step 179.
Return to step 166. In step 179, the first and second
Are closed, and the process returns to step 166.

According to the second embodiment, the first and second solenoid on-off valves 43 and 44 are provided at the refrigerant inlet / outlet of the heat source unit side heat exchanger 3, respectively, and the third solenoid on-off valve 45 is provided. A heat source device-side bypass pipe 42 that bypasses the heat source device-side heat exchanger 3 is provided through one end. By connecting to the pipe portion, a stable saturation temperature can be detected even when the gas refrigerant flows into the take-out pipe 21 while the heat source device side bypass pipe 42 is flowing. Therefore, also in the second embodiment, the same effect as in the first embodiment can be obtained.

Embodiment 3 FIG. 7 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 3 of the present invention. In the figure, reference numeral 36 denotes fourth temperature detecting means attached to a pipe connecting the three-way switching valve 79 and the third check valve 32. Reference numerals 41a, 41b, and 41c denote first, second, and third heat exchange elements constituting the heat source device-side heat exchanger 3, respectively. 75 is the first and second heat exchange elements 41
a, 41b connecting the first and second heat exchange elements 41 and 41b in parallel with each other through a first flow path 75.
The third heat exchange element 41c and the first flow path 75 are connected so that the liquid refrigerants from the liquid refrigerants a and 41b are merged and then heat exchanged again.
Are connected in series to a second connection pipe 7 through a second flow path connecting the two in series.

Reference numeral 77 is connected in parallel with the second flow path 76,
The second heat source device-side bypass pipe has a larger diameter than the second flow path 76, and is connected to the second connection pipe 7 by bypassing the third heat exchange element 41c. 78, 79 is the second
Is a three-way switching valve that can selectively switch between the flow path 76 and the second heat-source-unit-side bypass pipe 77, and these three-way switching valves 78 and 79 constitute a switching device 80.

Here, the operation of the third embodiment will be described. First, the case of only the cooling operation will be described. The high temperature and high pressure refrigerant gas discharged from the compressor 1
After passing through the direction valve 2, the heat is exchanged and condensed in the first and second heat exchange elements 41a and 41b of the heat source device side heat exchanger 3. Thereafter, the heat flows into the third heat exchange element 41c via the three-way switching valve 78, and heat exchange is performed again in the case where there is an imbalance in the heat exchange between the first and second heat exchange elements 41a and 41b. Thereafter, the operation reaches the three-way switching valve 79. Here, the first ports 78a, 79a and the second ports 78b, 79b of the three-way switching valves 78, 79 are open and the third ports 78c, 79c are closed. Other operations are described in the first embodiment.
Works the same as.

Next, the case of only the heating operation will be described. The refrigerant condensed and liquefied by exchanging heat with the indoor air in each of the indoor units B, C, and D passes through the first flow control device 9 and passes through the second connection pipes 7b, 7c, 7d on the indoor unit side to the second connection pipes. After flowing into the branch portion 11 and merging, the fourth flow control device 17
And reduced to a low pressure. Thereafter, the depressurized refrigerant passes through the first connection pipe 6, passes through the sixth check valve 35, the three-way switching valve 79, the second heat source unit-side bypass pipe 77, and the three-way switching valve 78, and passes through the first and the third valves. Second heat exchange elements 41a, 4
1b, heat exchanged, gaseous state, four-way valve 2,
It is sucked into the compressor 1 via the accumulator 4. Here, the first ports 78a, 78a,
79a and the third ports 78c, 79c are open, the second port 78
b and 79b are closed. Other operations are the same as those in the first embodiment.

Next, a description will be given of a case where heating and cooling are mainly performed in the simultaneous cooling and heating operation. Here, indoor units B and C
The case where the table is heating and one of the indoor units D is about to cool will be described. The refrigerant that has cooled and heated the indoor unit passes through the first connection pipe 6 and passes through the sixth check valve 35 and the three-way switching valve 7.
9, through the second heat source unit side bypass pipe 77 and the three-way switching valve 78, flow into the first and second heat exchange elements 41a and 41b to exchange heat. Other operations are the same as those in the first embodiment.

Next, the case of cooling-maintenance in simultaneous cooling and heating operation will be described. Here, indoor units B and C
The case where the stand is for cooling and one of the indoor units D is for heating will be described. The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, and is subjected to an arbitrary amount of heat exchange in the first and second heat exchange elements 41 a and 41 b of the heat source device side heat exchanger 3 to be two-phase High-pressure gas of the three-way switching valve 78,
It bypasses the third heat exchange element 41c and reaches the three-way switching valve 79 via the second heat source unit side bypass pipe 77. further,
The gas is sent from the three-way switching valve 79 to the gas-liquid separator 12 of the repeater E from the third check valve 32 and the second connection pipe 7. Other operations are the same as those in the first embodiment.

The case of the defrosting operation will be described with reference to FIG. Here, the defrosting operation when the three indoor units B, C, and D are about to heat will be described. The defrosting operation is performed only in the above-described heating operation, or in the heating main body, the fact that the heat source unit side heat exchanger 3 is frosted is determined by a decrease in the temperature detected by the fourth temperature detector 36, and the defrosting operation is performed. Move to Thereafter, the completion of defrosting is determined based on the rise in the temperature detected by the fourth temperature detector 36, and the defrosting operation is terminated.
In the defrosting operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is supplied to the four-way valve 2 as shown by the solid arrow in FIG.
And removes frost formed on the first and second heat exchange elements 41a and 41b while exchanging and condensing heat in the first and second heat exchange elements 41a and 41b of the heat source unit side heat exchanger 3. Frost. After passing through the first flow path 75, the three-way switching valve 78, the second
Flow path 76, third heat exchange element 41c, three-way switching valve 79
Through the third check valve 32. Immediately after the start of the defrosting operation, the third heat exchange element 41c located below the first and second heat exchange elements 41a, 41b is connected to the first and second heat exchange elements 41a, 41b located above. The dissolved water flows down to the lower third heat exchange element 41c, and is cooled by the water. The refrigerant passing through the second flow path 76 is supercooled, and the fourth temperature detector 36 Does not rise. First and second due to frost formation imbalance
The first, second, and third heat exchange elements 41a, 41b, even if there is a defrosting imbalance of the heat exchange elements 41a, 41b,
When all of the melted water has been defrosted and the melted water has flowed down to the third heat exchange and melting 41c, the degree of supercooling of the refrigerant passing through the second flow path 76 decreases, and the fourth temperature detector 36 Temperature rises. Here, the first ports 78a, 79a and the second ports 78b, 79b of the three-way switching valves 78, 79, respectively.
Is open, and the third ports 78c and 79c are closed.

From the third check valve 32, through the second connection pipe 7, the gas-liquid separation device 12, and the second flow control device 13, it flows into the second branch portion 11, and the indoor unit side The air flows into the indoor units B, C and D through the second connection pipes 7b, 7c and 7d. Then, the refrigerant is decompressed to a low pressure by the first flow control device 9, exchanges heat with the indoor air in the indoor heat exchanger 5, evaporates and is gasified. The refrigerant in the gas state is supplied to the first connection pipes 6b, 6b on the indoor unit side.
c, 6d, the three-way switching valve 8, the first branch 10, the first connection pipe 6, the fourth check valve 33, the four-way valve 2, and the accumulator 4 connected to the indoor units B, C, D. A circulation cycle is drawn through the compressor 1 through the compressor 1 and a defrosting operation is performed. At this time, the three-way switching valve 8 connected to the indoor units B, C, and D has a first port 8a closed, a second port 8b, and a third port 8 respectively.
c is open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure, the refrigerant necessarily flows to the third check valve 32 and the fourth check valve 33.

As described above, according to the third embodiment,
The heat-source-unit-side heat exchanger 3 includes at least first, second, and third heat exchange elements 41a, 41b, and 41c.
A first flow path that connects the first and second heat exchange elements 41a and 41b in parallel with each other and a second flow path that connects the third heat exchange element 41c in series are connected to the second connection pipe. And a heat source unit side bypass pipe for connecting the first flow path to the second connection pipe by bypassing the third heat exchange element 41c, and providing the first flow path to the third heat exchange element side or A switching device for selectively switching to the heat source unit side bypass pipe is provided. Therefore, cooling and heating can be selectively performed, and cooling can be performed simultaneously in one indoor unit and heating can be performed simultaneously in the other indoor unit. During the cooling operation, the heat source unit side heat exchanger 3
After the heat is exchanged and condensed in the first and second heat exchange elements 41a and 41b, the switching device again causes the third heat exchange element 4
By exchanging heat in 1c, even if there is an imbalance in heat exchange between the first and second heat exchange elements 41a and 41b, it is possible to sufficiently condense the liquid and distribute the liquid before being distributed to the indoor unit. The degree of supercooling of the refrigerant can be sufficiently obtained, and the distribution of the liquid refrigerant can be improved.

In the defrosting operation, heat is exchanged and condensed in the first and second heat exchange elements of the heat source unit side heat exchanger, and then defrosted by the switching device. In the case where the defrosting of the first and second heat exchange elements is unbalanced due to the frost formation imbalance, all of the first to third heat exchange elements are sufficiently defrosted. Since the refrigerant temperature at the outlet of the heat source unit side heat exchanger does not rise until the frost remains, it is possible to prevent the defrosting operation from ending with the frost remaining, which is caused by performing the heating operation with the frost remaining. Heating capacity shortage can be prevented.

Further, during the heating main operation, the switching device bypasses the third heat exchange element of the heat source unit side heat exchanger and passes the first and second heat exchange elements through the heat source unit side bypass pipe. To reduce the pressure loss generated by the low-pressure two-phase refrigerant passing through the heat exchanger on the heat source unit side, suppress the rise in evaporation temperature in the indoor unit that is about to be cooled, and improve the cooling capacity. Can be done. In the cooling-main operation, the first and second heat exchange elements of the heat exchanger on the heat source unit exchange the refrigerant, which has been heat-exchanged by an arbitrary amount to become a high-pressure two-phase, by the switching device for the third heat exchange. By bypassing the element and passing through the second heat source unit side bypass pipe, the pressure loss generated by passing through the heat source unit side heat exchanger is suppressed low, and the condensation temperature in the indoor unit to be heated is reduced. And the heating capacity can be improved.

In the third embodiment, two three-way switching valves 78 and 79 are provided. However, two three-way switching valves 78 and 79 are not necessarily required. Similar effects can be obtained.

Embodiment 4 In the third embodiment, the three-way switching valve 8 is provided to provide the first connection pipes 6b, 6b on the indoor unit side.
Although c and 6d are connected to the first connection pipe 6 or the second connection pipe 7 so as to be switchable, in the fourth embodiment, as shown in FIG. , 31 to provide the first connection pipes 6b, 6 on the indoor unit side.
c and 6d are connected to the first connection pipe 6 or the second connection pipe 7 so as to be switchable, and the same operation and effect can be obtained.

[0059]

Since the present invention is configured as described above, it has the following effects.

[0060]

[0061]

[0062] According to this inventions, the compressor, the plurality having a 4-way valve and one heat source equipment having a heat source unit side heat exchanger, and a and a first flow control device indoor heat exchanger In an air conditioner in which an indoor unit is connected to a pipe and a cooling / heating operation is performed by supplying a refrigerant from the heat source unit to a plurality of indoor units, the heat source unit side heat exchanger includes at least first, second, and third heat exchange units. The first and second heat exchange elements are connected in parallel with each other between the refrigerant inlet of the heat source unit side heat exchanger and the first flow path, and the third heat exchange element is connected to the third heat exchange element. 1st and 2nd
Connected between the second flow path connected to the first flow path so as to be in series with the heat exchange element and the liquid outflow side pipe of the heat source device side heat exchanger. A heat source unit side bypass pipe is provided which connects the flow path of the third heat exchange element to the liquid outlet side pipe of the heat source unit side heat exchanger by bypassing the third heat exchange element, and the first flow path is connected to the third heat exchange element side or Since a switching device for selectively switching to the heat source device side bypass pipe side is provided, during cooling operation, after the heat exchange and condensation in the first and second heat exchange elements of the heat source device side heat exchanger, the switching device is used. By performing heat exchange again in the third heat exchange element, even if there is an imbalance in heat exchange between the first and second heat exchange elements, the heat can be sufficiently condensed and distributed to the indoor unit. The degree of supercooling of the liquid refrigerant can be sufficiently obtained beforehand, improving the distribution of the liquid refrigerant. That. In the defrosting operation, the first and second heat exchange elements of the heat source unit side heat exchanger perform heat exchange and defrost by condensing, and then the switching device performs heat exchange again in the third heat exchange element. As a result, the refrigerant temperature at the outlet of the heat source unit side heat exchanger does not increase until all of the first to third heat exchange elements are sufficiently defrosted due to the frost imbalance, so that the frost remains as it is. Termination of the frost operation can be prevented, and insufficient heating capacity caused by performing the heating operation with frost remaining can be prevented. During the heating main operation, the switching device bypasses the third heat exchange element of the heat source unit side heat exchanger, passes through the heat source unit side bypass pipe, and evaporates in the first and second heat exchange elements. Thus, the pressure loss generated when the low-pressure two-phase refrigerant passes through the heat source device side heat exchanger can be suppressed low, the increase in the evaporation temperature in the indoor unit to be cooled can be suppressed, and the cooling capacity can be improved. At the time of the cooling main operation, the first heat exchange element and the second heat exchange element of the heat source unit-side heat exchanger exchange an arbitrary amount of heat to form a high-pressure two-phase refrigerant, and the switching device switches the third heat exchange element. By bypassing and passing through the heat source unit side bypass pipe, the pressure loss generated by passing through the heat source unit side heat exchanger is suppressed low, the reduction of condensation temperature in the indoor unit to be heated is suppressed, and the heating capacity Can be improved. Thus, an air conditioner capable of simultaneous cooling and heating operation that can selectively perform cooling and heating for each indoor unit, perform cooling in one indoor unit stably, and perform heating in the other indoor unit stably simultaneously.

[0063] Also, the first and second connection pipe connecting the heat source unit and a plurality of indoor units, switchably one of a plurality of indoor units to the first connection pipe or the second connecting pipe A first branch having a valve device to be connected, and a second branch connected to the other of the indoor heat exchangers of the plurality of indoor units via a first flow control device, and via a second flow control device; And a second branch section connected to the second connection pipe, and the liquid outlet pipe of the heat source unit side heat exchanger is connected to the second connection pipe. Can be selectively performed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a refrigerant circuit diagram for describing an operation state of only cooling or heating in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a refrigerant circuit diagram for describing an operating state mainly including heating in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 4 is a refrigerant circuit diagram for illustrating an operation state mainly including cooling in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 5 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a flowchart showing control contents of first to third solenoid on-off valves during a cooling main operation in the air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 7 is an overall configuration diagram centered on a refrigerant system of an air-conditioning apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a refrigerant circuit diagram for illustrating a defrosting operation state in the air-conditioning apparatus according to Embodiment 3 of the present invention.

FIG. 9 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 4 of the present invention.

FIG. 10 is an overall configuration diagram mainly showing a refrigerant system of a conventional air conditioner.

[Explanation of symbols]

A heat source unit, B, C, D indoor unit, E relay unit, 1 compressor, 2 4 way valve, 3 heat source unit side heat exchanger, 5 indoor side heat exchanger, 6 first connection pipe, 7 second Connection piping, 8
Three-way switching valve (valve device), 9 first flow control device, 1
0 first branch, 11 second branch, 12 gas-liquid separator, 13 second flow controller, 14 bypass pipe, 15 third flow controller, 17 fourth flow controller, 19th 1 heat exchange section, 21 extraction pipe, 22
Throttling device, 23 second temperature detecting means (temperature detector), 40 flow path switching device, 41a first heat exchange element, 41b second heat exchange element, 41c third heat exchange element, 42 heat source device side Bypass pipe, 43 first electromagnetic on / off valve, 44 second electromagnetic on / off valve, 45 third electromagnetic on / off valve, 75 first flow path, 76 second flow path, 77 second
Heat source equipment side bypass pipe (heat source equipment side bypass pipe), 80
Switching device.

──────────────────────────────────────────────────続 き Continuation of the front page (31) Priority claim number Japanese Patent Application No. 3-10415 (32) Priority date Hei 3 (1991) January 31 (33) Priority claim country Japan (JP) (31) Priority Claim number Japanese Patent Application No. 3-10710 (32) Priority Date Heisei 3 (1991) January 31 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-10711 (32) Priority Japan Heisei 3 (1991) January 31 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-14031 (32) Priority Japan Heisei 3 (1991) February 5 (33) ) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No.3-14162 (32) Priority date Heisei 3 (1991) February 5 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-14200 (32) Priority Date Heisei 3 (1991) February 5 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-26000 (32) )priority Hei 3 (1991) February 20 (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-26001 (32) Priority date Hei 3 (1991) February 20 (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-64631 (32) Priority date Hei 3 (1991) March 28 (33) Priority claim country Japan (JP) (72) Invention Tomohiko Kasai 6-66, Teira, Wakayama-shi Mitsubishi Electric Corporation Wakayama Works (72) Inventor Shigeo Takada 6-66, Tehira Wakayama-shi Mitsubishi Electric Corporation Wakayama Works (72) Inventor Kameyama Junichi 6-5-66, Teira, Wakayama-shi Mitsubishi Electric Corporation Wakayama Works (56) References JP-A-62-87767 (JP, A) JP-A-61-134545 (JP, A) JP-A-2-2 230070 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F25B 29/00 361 F25B 6/00 F25B 13/00 104 F25B 47/02 550

Claims (2)

(57) [Claims] 1. A piping system comprising one heat source unit having a compressor, a four-way valve and a heat source unit side heat exchanger, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device. In the air conditioner connected and supplied with a refrigerant from the heat source unit to the plurality of indoor units to perform a cooling and heating operation, the heat source unit-side heat exchanger includes at least a first, a second, and a third heat exchange element. Wherein the first and second heat exchange elements are connected in parallel with each other between a refrigerant inlet and a first flow path of the heat source unit side heat exchanger, and the third heat exchange element is Between a second flow path connected to the first flow path so as to be in series with the first and second heat exchange elements, and a liquid outlet side pipe of the heat source unit side heat exchanger; Connected to the first heat path and bypassing the third heat exchange element. The heat source apparatus side bypass pipe provided to be connected to the liquid outlet side pipe of exchanger, the first
An air conditioner comprising a switching device for selectively switching the flow path of the third heat exchange element to the third heat exchange element side or the heat source device side bypass pipe side. 2. A first and a second connection pipe for connecting a heat source unit and a plurality of indoor units, and one of the plurality of indoor units is switched to the first connection pipe or the second connection pipe. A first branch unit having a valve device to be connected to the second indoor unit, and a second flow control unit connected to the other of the indoor heat exchangers of the plurality of indoor units via a first flow control device. A second branch portion connected to the second connection pipe via a device, wherein a liquid outflow side pipe of the heat source unit side heat exchanger is connected to the second connection pipe. The air conditioner according to claim 1, characterized in that: