JP2718286B2 - 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 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 an indoor unit and heating in the other indoor unit, and particularly to control of a refrigerant flow control device, an on-off valve, and an indoor blower.

[0002]

2. Description of the Related Art The prior art of an air conditioner according to the present invention will be described below with reference to the drawings. FIG. 8 is an overall configuration diagram mainly showing a refrigerant system of an air conditioner showing a conventional technique. 9 to 11 show operating states of the air-conditioning apparatus shown in FIG. 8 during a cooling / heating operation.
Is the operation state diagram of only cooling or heating, FIG. 10 and FIG.
11 shows the operation of simultaneous cooling and heating operation, FIG. 10 shows the main heating (when the heating operation capacity is larger than the cooling operation capacity),
FIG. 11 is an operation state diagram showing the cooling main body (when the cooling operation capacity is larger than the heating operation capacity). Note that, in this description, 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. 8, 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. 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, and 4 is an accumulator, which is connected to the compressor 1 via the four-way valve 2. I have. 5 is an indoor heat exchanger provided in three indoor units B, C and D, and 6 is a heat source unit A
A thick first connection pipe for connecting the four-way valve 2 and the repeater E,
6b, 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; It is a second connection pipe that is thinner than the first connection pipe that connects the heat source unit side heat exchanger 3 of the heat source unit A and the relay unit E. 7b, 7c and 7d connect the indoor side heat exchangers 5 of the indoor units B, C and D and the repeater E via the first flow control device 9, respectively.
Is a second connection pipe on the indoor unit side corresponding to FIG. Reference numeral 21 denotes a first connection pipe 6b, 6c, 6d on the indoor unit side and a first connection pipe 6
A first on-off valve 22 for connecting the first connection pipes 6b, 6c, 6d on the indoor unit side and a second connection pipe 7 for connecting the second connection pipe 7;
It is an on-off valve.

Reference numeral 9 denotes a first flow rate control device which is connected in proximity to the indoor heat exchanger 5 and which is controlled by a superheat amount during cooling and a subcool amount during heating at the outlet side of the indoor heat exchanger 5. Are connected to the second connection pipes 7b, 7c, 7d on the indoor unit side. 10 is the first connection pipe 6b, 6c, 6d on the indoor unit side
And a first branch portion provided with a first on-off valve 21 and a second on-off valve 22 that are switchably connected to the first connection pipe 6 or the second connection pipe 7. 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. Reference numeral 12 denotes a gas-liquid separation device provided in the middle of the second connection pipe 7. The gas layer portion is connected to the second on-off valve 22 of the first branch portion 10, and the liquid layer portion is connected to the second opening / closing valve 22. Are connected to the branch portion 11. 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.

[0005] Reference numeral 14 denotes a bypass pipe connecting the second branch portion 11 and the first connection pipe 6, and reference numeral 15 denotes a third flow control device (here, an electric expansion valve) provided in the middle of the bypass pipe 14. , 16a are provided downstream of a third flow control device 15 provided in the middle of the bypass pipe 14, and are associated with the second connection pipes 7b, 7c, 7d on the indoor unit side in the second branch section 11. And a second heat exchange section for performing heat exchange between the first heat exchanger and the second heat exchanger. 16
b, 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 exchanging section for exchanging heat with 7d.

Reference numeral 19 is provided on the bypass pipe 14 downstream of the third flow control device 15 and downstream of the second heat exchange section 16a, and connects the gas-liquid separation device 12 to the second flow control device 13. The first heat exchange section that exchanges heat with the piping, 17 is the second heat exchange section
Openable and closable fourth flow control device (here, an electric expansion valve) connected between the branch portion 11 and the first connection pipe 6.
It is. On the other hand, 32 is the heat source unit side heat exchanger 3 and the second
A third check valve provided between the connection pipe 7 and
The refrigerant is allowed to flow only from the heat source unit side heat exchanger 3 to the second connection pipe 7. Reference numeral 33 denotes a fourth check valve provided between the four-way valve 2 of the heat source unit A and the first connection pipe 6, and only a fourth check valve is provided from the first connection pipe 6 to the four-way valve 2. Allow refrigerant flow.

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 extends from the four-way valve 2 to the second connection pipe. Only the refrigerant flow to 7 is allowed. Reference numeral 35 denotes a sixth check valve provided between the heat source unit-side heat exchanger 3 and the first connection pipe 6, and a sixth check valve 35 from the first connection pipe 6 to the heat source unit-side heat exchanger 3. Only the refrigerant flow is allowed. The third, fourth, fifth, and sixth check valves 32, 33, 34, and 35 constitute a flow path switching valve device 40. 50 is a first service port provided in the first connection pipe 6,
Reference numeral 51 denotes a second service port provided in the second connection pipe. 25 is the first branch 10 and the second flow control device
The first pressure detecting means provided between 13 and 26 corresponds to the second pressure detecting means.
This is a second pressure detecting means provided between the flow control device 13 and the fourth flow control device 17.

Next, the operation will be described. First, the case of only the cooling operation will be described with reference to FIG. As shown by the solid arrows in FIG. 2, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2 and exchanges heat with outdoor air in the heat source unit side heat exchanger 3 to be condensed and liquefied. 3 check valve 32, second connection pipe 7, gas-liquid separator 12, second flow controller
13 and the second branch portion 11 and the second unit on the indoor unit side.
And flows into the indoor units B, C and D through the connection pipes 7b, 7c and 7d. 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 superheat amount 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 gaseous refrigerant is supplied to the first connection pipes 6b, 6c, 6d on the indoor unit side, the first on-off valve 21, the first connection pipe 6, the fourth check valve 33, the heat source A circulation cycle is drawn into the compressor 1 through the four-way valve 2 and the accumulator 4 of the compressor, and performs a cooling operation. At this time, the first on-off valve 21 is open, and the second on-off valve 22 is closed. 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.

At the time of 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, 16d between the second connection pipes 7b, 7c, 7d on the indoor unit side of the second branch section 11 and the second heat exchange section.
At 16a, the second connection pipe 7 on each indoor unit side of the second branch portion 11
b, 7c, 7d, the first heat exchange section 19
Then, the refrigerant that has exchanged heat with the refrigerant flowing into the second flow control device 13 and evaporates enters the first connection pipe 6 and the fourth check valve 33, and the four-way valve 2 of the heat source device, It is sucked into the compressor 1 via 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 branching unit 11 is sufficiently subcooled.
Flows into the indoor units B, C, and D to be cooled.

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, the fifth check valve 34, the second connection pipe 7, the gas-liquid separation After passing through the device 12, the second on-off valve 22 and the first connection pipes 6b, 6c, 6d on the indoor unit side flow into the indoor units B, C, D in order, and exchange heat with indoor air to condense. It liquefies and heats the room.

The refrigerant in the liquid state is controlled by the subcooling amount at the outlet of each indoor side heat exchanger 5, passes through the first flow control device 9 which is almost fully opened, and the second connection on the indoor unit side. The pipes 7b, 7c, and 7d flow into the second branch portion 11 and merge there, and further pass through the fourth flow control device 17. Here, the first
The pressure is reduced to the low-pressure gas-liquid two-phase state by either the flow control device 9 or the fourth flow control device 17. The refrigerant decompressed to a low pressure flows into the sixth check valve 35 of the heat source unit A and the heat source unit side heat exchanger 3 via the first connection pipe 6, where it exchanges heat with outdoor air and evaporates. The refrigerant in the gaseous state forms a circulation cycle that is drawn into the compressor 1 via the four-way valve 2 and the accumulator 4 of the heat source unit, and performs a heating operation. At this time, the second on-off valve 22 is open and the first on-off valve 21 is closed. At this time, the refrigerant naturally flows to the fifth check valve 34 and the sixth check valve 35 because the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure.

Next, a description will be given of a case where heating and cooling are mainly performed in the simultaneous cooling and heating operation with reference to FIG. The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 as shown by a dotted arrow in FIG.
It is sent to the repeater E through the four-way valve 2 through the fifth check valve 34 and the second connection pipe 7, passes through the gas-liquid separation device 12, the second on-off valve 22, and the first on the indoor unit side. The air flows into the indoor units B and C to be heated in the order of the connection pipes 6b and 6c, and exchanges heat 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 of the indoor heat exchangers B and C, passes through the first flow control device 9 which is almost fully opened, and is slightly depressurized to the second branch. Flow into 11. A part of the refrigerant passes through the second connection pipe 7d on the indoor unit side, and is cooled by the indoor unit D to be cooled.
And enters the first flow control device 9 controlled by the amount of superheat at the outlet of the indoor heat exchanger D, and after being decompressed, enters the indoor heat exchanger 5 and exchanges heat to evaporate the gas. In this state, the room is cooled, and flows into the first connection pipe 6 via the first connection pipe 6d via the first on-off valve 21.

On the other hand, the other refrigerant is controlled by a fourth flow control device 17 which is controlled so that the pressure difference between the detected pressure of the first pressure detecting means 25 and the detected pressure of the second pressure detecting means 26 falls within a predetermined range.
And flows into the sixth check valve 35 of the heat source unit A and the heat source unit side heat exchanger 3 through the thick first connection pipe 6 through the thick first connection pipe 6 through the indoor unit D to be cooled. Then, it exchanges heat with the outdoor air and evaporates to a gas state.

This refrigerant forms 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 indoor unit D to be cooled
The difference between the evaporation pressure of the indoor heat exchanger 5 and the pressure of the heat source side heat exchanger 3 becomes smaller because the first connection pipe 6 is switched to the thicker one. At this time, the second on-off valves 22 corresponding to the indoor units B and C are open, and the first on-off valve 21 is closed. Further, the first on-off valve 21 corresponding to the indoor unit D is open, and the second on-off valve 22 is closed. At this time, the refrigerant
The connection pipe 6 of low pressure and the second connection pipe 7 of high pressure inevitably flow to the fifth check valve 34 and the sixth check valve 35 because of high pressure.

In 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 15 The pressure is reduced to a low pressure in the third heat exchange sections 16b, 16c and 16d.
Between the second connection pipes 7b, 7c and 7d of the branch unit 11 on the indoor unit side, and the second connection of the second branch unit 11 on the indoor unit side at the second heat exchange unit 16a. Heat is exchanged between the junctions of the pipes 7b and 7c, and the evaporated refrigerant is supplied to the first connection pipe 6, the sixth connection pipe.
, 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 branch portion 11 which exchanges heat in the second and third heat exchange portions 16a, 16b, 16c and 16d, is cooled, and is sufficiently subcooled is provided.
Flows into the indoor unit D to be cooled.

Next, a description will be given of a case where cooling is mainly performed in simultaneous cooling and heating operation with reference to FIG. As shown by solid arrows in FIG. 1, 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 exchanges heat with the outdoor air to form a gas-liquid mixture. A two-phase high-temperature high-pressure state results. Thereafter, the two-phase high-temperature and high-pressure refrigerant is supplied to the third check valve 32,
After passing through the second connection pipe 7, it is sent to the gas-liquid separation device 12 of the repeater E. Here, it is separated into gaseous refrigerant and liquid refrigerant,
The separated gaseous refrigerant flows into the indoor unit D to be heated in the order of the second on-off valve 22 and the first connection pipe 6d on the indoor unit side, and flows into the indoor heat exchanger 5 with indoor air. Heat exchange to condense and liquefy and heat the room. Further, it is controlled by the subcool amount at the outlet of the indoor heat exchanger 5, passes through the first flow control device 9 in a substantially fully opened state, and flows into the second branch portion 11 after being slightly reduced in pressure.

On the other hand, the remaining liquid refrigerant passes through the second flow control device 13 controlled by the detected pressure of the first pressure detecting means 25 and the detected pressure of the second pressure detecting means 26, and passes through the second branch. The refrigerant flows into the unit 11, merges with the refrigerant that has passed through the indoor unit D to be heated, and flows into the indoor units B and C in the order of the second connection pipes 7b and 7c on the indoor unit side. The refrigerant flowing into each of the indoor units B and C is decompressed to a low pressure by the first flow control device 9 controlled by the amount of superheat at the outlet of the indoor heat exchangers B and C, and exchanges heat with the indoor air. It evaporates, gasifies, and cools the room. Further, the refrigerant in this gas state passes through the first connection pipes 6b and 6c on the indoor unit side and the first opening / closing valve 21, and passes through the first connection pipe 6 and 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 the cooling-main operation is performed.

The first on-off valves 21 corresponding to the indoor units B and C are open, and the second on-off valves 22 are closed. Furthermore,
The second on-off valve 22 corresponding to the indoor unit D is open, and the first on-off valve 21 is closed. 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 liquid refrigerant enters the bypass pipe 14 from the junction of the second connection pipes 7b, 7c, 7d on the indoor unit side of the second branch section 11, and enters the third flow control device 15 The pressure is reduced to a low pressure in the second heat exchangers 16b, 16c, and 16d, and between the second connection pipes 7b, 7c, and 7d on the indoor unit side of the second branch unit 11 and the second heat exchangers 16b, 16c, and 7d.
The second heat exchanger 16a at the side of each indoor unit of the second branch 11
The first heat exchange unit 19 performs heat exchange with the refrigerant flowing into the second flow control device 13 between the junctions of the connection pipes 7b, 7c, and 7d. 1 connection piping 6,
The heat enters the fourth check valve 33 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 first, second, third
The second branch portion 11 which has been cooled by heat exchange in the heat exchange portions 19, 16a, 16b, 16c, and 16d, and has a sufficient subcool.
Flows into the indoor units B and C to be cooled.

[0021]

Since the conventional multi-chamber and heat pump type air conditioners are constructed as described above, when the indoor unit starts the cooling operation, the first on-off valve is opened and the air conditioner is opened simultaneously. Then, the first flow control device has started the flow control of the refrigerant according to the cooling load. However, if the indoor unit is operated by heating before stopping, the high-pressure gas remains in the first connection pipe on the indoor unit side and the indoor heat exchanger, so that the next cooling operation is performed. During operation, there is a problem in that high-pressure gas is introduced into the low-pressure section and decompresses and expands to generate noise. As an approximation technique, Japanese Patent Application Laid-Open No.
No. 72 publication.

The present invention has been made in order to solve the above-mentioned problems. A plurality of indoor units are connected to one heat source unit, and cooling and heating are selectively performed for each indoor unit. In a multi-room heat pump type air conditioner capable of simultaneously performing cooling in one indoor unit and heating in the other indoor unit, refrigerant noise generated in the first branch of the repeater at the start of cooling operation of the indoor unit The object is to obtain an air conditioner excellent in silence.

[0023]

An air conditioner according to the present invention is an air conditioner for an indoor unit of an indoor unit in a refrigeration cycle.
A first switching valve that is a cooling switching switching valve connected to the
A second on-off valve that is a heating-switching on-off valve and the indoor heat
A first flow control device connected to the other end of the exchanger;
Flow capacity of this first on-off valve bypassing the first on-off valve
A third opening / closing valve having a smaller capacity, wherein when the indoor unit starts the cooling operation, the third opening / closing valve is opened and the indoor blower is started, and the opening time of the third opening / closing valve is set to After a lapse of a predetermined time, the first on-off valve is opened and the first
Is controlled to a flow rate according to the cooling load to perform the cooling operation.

[0024]

According to the air conditioner of the present invention, when the indoor unit starts the cooling operation, the third opening / closing valve having a smaller capacity than the flow capacity of the first opening / closing valve is opened, and the room is stopped during the heating operation.
High-pressure refrigerant filled in the inner connection pipe escapes to the low-pressure side
Together to a high pressure cold holding start the indoor blower predetermined time
Since the medium is condensed and reduced in pressure , the first on-off valve is opened and the first flow control device is controlled to flow in accordance with the cooling load, thereby suppressing the generation of refrigerant noise at the start of cooling operation. it can.

[0025]

[Embodiment 1] Hereinafter, embodiments of the present invention will be described. FIG. 1 is an overall configuration diagram mainly showing a refrigerant of an air conditioner according to an embodiment of the present invention. FIGS. 2 to 4 show an operation state during the cooling / heating operation in the embodiment shown in FIG. 1. FIG. 2 is an operation state diagram of only the cooling or heating operation, and FIGS. FIG. 3 is an operation state diagram showing the main heating operation (when the heating operation capacity is larger than the cooling operation capacity), and FIG. 4 is an operation operation state diagram mainly showing the cooling operation (when the cooling operation capacity is larger than the heating operation capacity). In this embodiment, 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 denotes a first branch 10, a second flow controller 13, a second branch 11, a gas-liquid separator 12, a heat exchanger 16a, 16b, 16c, 16d, 19, a third Is a repeater incorporating the fourth flow control device 17 and the fourth flow control device 17. Further, 1 is a compressor, 2 is a four-way switching valve for switching the refrigerant flow direction of the heat source machine, 3 is a heat source side heat exchanger, and 4 is an accumulator, which is connected to the compressor 1 via the four-way switching valve 2. I have. These constitute the heat source device A. Reference numeral 5 denotes an indoor heat exchanger provided in the three indoor units B, C, and D, reference numeral 80 denotes an indoor blower, and reference numeral 6 denotes a four-way switching valve 2 of the heat source unit A and a fourth unit to be described later. Thick first connecting pipe connected through check valve 33, 6b, 6c, 6d
Are connected to the indoor heat exchangers 5 of the indoor units B, C, and D and the relay unit E, respectively, and are connected to the first connection pipe 6 on the indoor unit side, and 7 is a heat source of the heat source unit A. A second connection pipe, which is thinner than the first connection pipe, connects the machine-side heat exchanger 3 and the relay machine E via a third check valve 32 described later.

Also, 7b, 7c, 7d are indoor units B,
A second connection pipe on the indoor unit side corresponding to the second connection pipe 7, wherein the indoor heat exchangers 5 of C and D and the repeater E are connected via the first flow control device 9. 21 is a first opening / closing valve connecting the first connection pipes 6b, 6c, 6d on the indoor unit side to the first connection pipe 6, and 22 is the first connection pipes 6b, 6c on the indoor unit side.
A second on-off valve for connecting the second connection pipe 7 to the second on-off valve 6d, 23
Is a first on-off valve that bypasses the entrance of the first on-off valve 21
This is a third on-off valve having a smaller flow capacity than 21. 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 machine side. Reference numeral 10 denotes a first on-off valve 21 and a second on-off valve which switchably connect the first connection pipes 6b, 6c, 6d on the indoor unit side to the first connection pipe 6 or the second connection pipe 7. 22, a first branching portion provided with a third on-off valve 23 that further bypasses the entrance and exit of the first on-off valve 21. 11 is a second connection pipe 7b, 7c, 7d on the indoor unit side,
This is a second branch portion including the second connection pipe 7. Reference numeral 12 denotes a gas-liquid separation device provided in the middle of the second connection pipe 7. The gas phase portion is connected to the second on-off valve 22 of the first branch portion 10, and the liquid phase portion is connected to the second It is connected to the branch unit 11. 13
Is 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
It is.

Reference numeral 14 denotes a bypass pipe connecting the second branch portion 11 and the first connection pipe 6, and reference numeral 15 denotes a third flow control device (here, an electric expansion valve) provided in the middle of the bypass pipe 14. , 16a are provided downstream of a third flow control device 15 provided in the middle of the bypass pipe 14, and are associated with the second connection pipes 7b, 7c, 7d on the indoor unit side in the second branch section 11. And a second heat exchange section for performing heat exchange between the first heat exchanger and the second heat exchanger. 16
b, 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 exchanging section for exchanging heat with 7d. Reference numeral 19 denotes a pipe provided between the bypass pipe 14 downstream of the third flow control device 15 and downstream of the second heat exchange unit 16a, and connecting the gas-liquid separation device 12 and the second flow control device 13. 1st heat exchange section which exchanges heat between, 17 is the 2nd branch section
A fourth flow control device (here, an electric expansion valve) that can be opened and closed is connected between the first connection pipe 6 and the first connection pipe 6.

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. 2 connection piping 7
Only the refrigerant flow is allowed. Reference numeral 33 denotes a fourth valve provided between the four-way switching valve 2 of the heat source unit A and the first connection pipe 6.
And allows the refrigerant to flow only from the first connection pipe 6 to the four-way switching valve 2. Reference numeral 34 denotes a fifth check valve provided between the four-way switching valve 2 of the heat source unit A and the second connection pipe 7.
Is allowed to flow only to the connection pipe 7. Reference numeral 35 denotes a sixth check valve provided between the heat source unit-side heat exchanger 3 and the first connection pipe 6, and a sixth check valve 35 from the first connection pipe 6 to the heat source unit-side heat exchanger 3. Only the refrigerant flow is allowed. The third, fourth, fifth, and sixth check valves 32, 33, 34, and 35 constitute a flow path switching valve device 40.

Reference numeral 25 denotes a first pressure detecting means provided between the first branch section 10 and the second flow control device 13, and reference numeral 26 denotes a second flow control device 13 and a fourth flow control device. This is second pressure detection means provided between the apparatus and the apparatus 17.

Next, the operation 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 switching valve 2, exchanges heat with air in the heat source unit side heat exchanger 3, and is condensed. The check valve 32, the second connection pipe 7, the gas-liquid separation device 12, and the second flow control device 13 follow in this order, and further the second branch portion 11, the second connection pipe 7b, 7c on the indoor unit side, The air flows into each of the indoor units B, C, and D through 7d. 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 superheat amount 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 the gaseous state is supplied to the first connection pipes 6b, 6c, 6d, the first on-off valve 21, the third on-off valve 23, the first connection pipe 6, and the fourth connection pipe 6b, 6c, 6d on the indoor unit side. Check valve 33, heat source unit A
A circulation cycle is drawn into the compressor 1 through the four-way switching valve 2 and the accumulator 4 to perform the cooling operation. At this time, the first on-off valve 21 and the third on-off valve 23 are open, and the second on-off valve 22 is closed. 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. At the time of 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 units 16b, 16c,
16d, the second connection pipe 7 on each indoor unit side of the second branch portion 11
b, 7c, 7d, and the second heat exchange section 16a.
Between the second connecting pipes 7b, 7c, 7d on the indoor unit side of the branch section 11 and the refrigerant flowing into the second flow control device 13 in the first heat exchange section 19 The refrigerant that has undergone heat exchange and evaporates enters the first connection pipe 6 and the fourth check valve 33,
The heat is sucked into the compressor 1 via the four-way switching valve 2 and the accumulator 4 of the heat source unit A.

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

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 switching valve 2, the fifth check valve 34, the second connection pipe 7,
After passing through the gas-liquid separator 12, the second on-off valve 22, and the first connection pipes 6b, 6c, 6d on the indoor unit side in this order, the indoor units B, C,
It flows into D, exchanges heat with room air, condenses and liquefies, and heats the room.

The refrigerant in the liquid state is controlled by the subcooling amount at the outlet of each indoor heat exchanger 5, passes through the first flow control device 9 which is almost fully opened, and the second connection on the indoor unit side. The pipes flow into the second branch portion 11 from the pipes 7b, 7c, and 7d, join together, and further pass through the fourth flow control device 17. Here, the first flow control device 9 or the third and fourth flow control devices 15 and 17 are used.
The pressure is reduced to a low-pressure gas-liquid two-phase state in one of the two.
The refrigerant decompressed to a low pressure flows into the sixth check valve 35 of the heat source device A and the heat source device side heat exchanger 3 via the first connection pipe 6, and exchanges heat with air to evaporate to a gas state. , Heat source machine A
A circulation cycle is drawn into the compressor 1 via the four-way switching valve 2 and the accumulator 4 to perform a heating operation. At this time, the second on-off valve 22 is open, and the first on-off valve 21 and the third on-off valve 23 are closed. At this time, the refrigerant naturally flows to the fifth check valve 34 and the sixth check valve 35 because the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure. At this time, the second flow control device 13 is usually in a predetermined minimum opening state.

Next, the case of mainly heating in the simultaneous cooling and heating operation will be described with reference to FIG. The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 as shown by a dotted arrow in FIG.
Through the four-way switching valve 2, the fifth check valve 34 and the second connection pipe 7
Through the gas-liquid separator 12, through the second on-off valve 22, the first connection pipes 6b and 6c on the indoor unit side, and to each of the indoor units B and C to be heated. Inflow,
The indoor heat exchanger 5 exchanges heat with indoor air to condense and liquefy, thereby heating the room. The condensed and liquefied refrigerant is controlled by the subcooling amount at the outlet of each indoor heat exchanger 5, passes through the first flow control device 9 which is almost fully opened, and flows into the second branch portion 11 after being slightly reduced in pressure.

A 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 superheat amount at the outlet of the indoor heat exchanger 5. After entering the first flow control device 9 and being depressurized, it enters the indoor heat exchanger 5 and exchanges heat to evaporate to a gaseous state to cool the room and to cool the room through the first connection pipe 6d. On-off valve
21, flows into the first connection pipe 6 via the third on-off valve 23. On the other hand, the other refrigerant passes through a fourth flow control device 17 which is controlled so that the pressure difference between the detected pressure of the first pressure detecting means 25 and the detected pressure of the second pressure detecting means 26 is within a predetermined range. The sixth check valve of the heat source unit A passes through the thick first connection pipe 6 by merging with the refrigerant that has passed through the indoor unit D to be cooled.
35, flows into the heat source unit side heat exchanger 3, exchanges heat with air and evaporates to a gaseous state.

This refrigerant forms a circulation cycle that is drawn into the compressor 1 through the four-way switching valve 2 and the accumulator 4 of the heat source unit A, 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 on-off valve 22 connected to the indoor units B and C is open, and the first on-off valve 21 and the third on-off valve 23 are closed. The first on-off valve 21 and the third on-off valve 23 connected to the indoor unit D are open, and the second on-off valve 22 is closed. At this time, the refrigerant is supplied to the first connection pipe 6
Is low pressure, and the second connection pipe 7 flows through the fifth check valve 34 and the sixth check valve 35 inevitably due to the high pressure.

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 15 The second connection pipes 7b, 7c, 7d on the indoor unit side of the second branching section 11 in the third heat exchange sections 16b, 16c, 16d
And the second heat exchange unit 16a performs heat exchange with the junction of the second connection pipes 7b and 7c on the indoor unit side of the second branch unit 11 in the second heat exchange unit 16a. After passing through the first connection pipe 6 and the sixth check valve 35, the heat enters the heat source unit side heat exchanger 3 and exchanges heat with air to evaporate and naturalize, the four-way switching valve 2 of the heat source unit A,
It is sucked into the compressor 1 via the accumulator 4. on the other hand,
The refrigerant in the second branch portion 11, which has been subjected to heat exchange in the second and third heat exchange portions 16a, 16b, 16c, and 16d, cooled, and sufficiently cooled, flows into the indoor unit D to be cooled. I do. At this time, the second flow control device 13 is usually in a predetermined minimum opening state.

Next, a description will be given of a case where cooling is mainly performed in simultaneous cooling and heating operation 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 flows into the heat source device side heat exchanger 3 via the four-way switching valve 2,
It exchanges heat with air to be in a gas-liquid two-phase high temperature and high pressure state. Thereafter, the two-phase high-temperature and high-pressure refrigerant is supplied to the third check valve 32,
After passing through the second connection pipe 7, it is sent to the gas-liquid separation device 12 of the repeater E. Here, it is separated into gaseous refrigerant and liquid refrigerant,
The separated gaseous refrigerant passes through the second on-off valve 22, the first connection pipe 6d on the indoor unit side in this order, and the indoor unit D to be heated is heated.
And heat exchanges with the indoor air in the indoor heat exchanger 5 to condense and liquefy and heat the room. Further, the pressure 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 controlled by the pressure detected by the first pressure detecting means 25 and the pressure detected by the second pressure detecting means 26, and passes through the second branch. The refrigerant flows into the unit 11 and merges with the refrigerant that has passed through the indoor unit D to be heated. The second branch 11 flows into the indoor units B and C in the order of the second connection pipes 7b and 7c on the indoor unit side. The refrigerant flowing into the indoor units B and C is depressurized 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, and then the refrigerant flows into the indoor side heat exchanger 5. Inflow, heat exchange with indoor air, evaporate and gasify,
Cool the room. Further, the refrigerant in this gas state is
First connection pipes 6b and 6c on the indoor unit side, first on-off valve 21, third on-off valve 23, first connection pipe 6, fourth check valve 33, four-way switching valve 2 of heat source unit A A circulation cycle is drawn into the compressor 1 via the accumulator 4, and the cooling-main operation is performed. At this time, the first on-off valve 21 and the third on-off valve 23 connected to the indoor units B and C are open, and the second on-off valve 22 is closed. The second on-off valve 22 connected to the indoor unit D is open, and the first on-off valve 21 and the third on-off valve 23 are closed. 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 third check valve 32 and the fourth
To the check valve 33.

In this cycle, a part of the liquid refrigerant enters the bypass pipe 14 from the junction of the second connection pipes 7b, 7c, 7d on the indoor unit side of the second branch section 11, and the third flow rate Control device 15
The pressure is reduced to a low pressure in the third heat exchange sections 16b, 16c, 16c.
d, a second connection pipe 7b on each indoor unit side of the second branch portion 11,
7c and 7d, and between the second heat exchanger 16a and the junction of the second connection pipes 7b, 7c and 7d on the indoor unit side of the second branch 11 and The first heat exchange section 19 exchanges heat 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 the heat source device A is sucked into the compressor 1 through the four-way switching valve 2 of A and the accumulator 4. On the other hand, the first, second, and third heat exchange units 19, 16
The refrigerant in the second branch portion 11, which has been cooled by the heat exchange at a, 16b, 16c, and 16d and sufficiently subcooled, flows into the indoor units B and C to be cooled.

Next, control of the first opening / closing valve 21, the third opening / closing valve 23, the first flow control device 9, and the indoor blower 80 when the indoor unit starts the cooling operation will be described. FIG.
The first opening / closing valve 21, the third opening / closing valve 23, the first flow control device 9 and the control mechanism of the indoor blower 80 are shown, 60 is valve control means, 61 is first time measuring means, and 62 is flow control means. , 63 are indoor blower control means, and 64 is second time measuring means. FIG.
5 is a flowchart showing control contents of a valve control means 60, a first time measurement means 61, a flow rate control means 62, an indoor blower control means 63, and a second time measurement means 64. FIG. 7 is a graph showing a pressure change at a connection portion between the first branch portion 10 of the repeater and the first connection pipes 6a, 6b, 6c on the indoor side.

When the indoor unit in this embodiment starts the cooling operation, the third opening / closing valve 23 of the repeater is opened, the indoor blower 80 is started, and the opening / closing state of the third opening / closing valve and the first opening / closing state are set. After a lapse of a predetermined time in the closed state of the flow control device 9, the first opening / closing valve 21 is opened, and the flow control of the first flow control device 9 is performed according to the cooling load. By the above control, for example, when the indoor unit before the operation starts is stopped in the heating operation, the cooling operation is started from the state in which the inside of the first connection pipes 6b, 6c, and 6d on the indoor side is filled with the high-pressure gas. Also, the high pressure gas is bypassed to the low pressure part by the third opening / closing valve 23, and the pressure inside the first connection pipes 6b, 6c, 6d is further reduced by the air from the indoor blower.
A first branch 10 of the repeater and a first connection pipe 6a on the indoor side,
The pressure change at the connection between 6b and 6c is a gentle change as shown in FIG. 7, and no refrigerant noise accompanied by a rapid pressure change is generated.

Finally, the valve control means 6 in this embodiment is
The control contents of the first time measuring means 61, the second time measuring means 64, the flow control device 62 and the indoor blower control means 63 will be described with reference to the flowchart shown in FIG. When the indoor unit starts the cooling operation, in step 70, the third on-off valve 23 is opened, and in step 71, the operation of the blower 80 is started. Also,
In steps 71 and 72, the first timer 61 and the second timer 64 start timing. In step 74, it is determined whether or not the counted time is a predetermined time. If it is determined that the predetermined time has been reached, the flow proceeds to step 75 to start the first on-off valve 21, and in step 76, the first flow control device 9 Is controlled in accordance with the cooling load.

[0046]

As described above, according to the present invention, when the indoor unit starts the cooling operation, the third on-off valve having a smaller flow capacity than the first on-off valve is opened to perform the heating operation. Stop at
The high-pressure refrigerant filled in the connection pipe on the indoor side during
And the indoor blower is started, and the open state of the third on-off valve elapses for a predetermined time , and the high-pressure refrigerant condenses.
After the low pressure of the first on-off valve is open. Thus flow control in accordance with the first flow control device to the cooling load, it is possible to suppress refrigerant noise due to rapid pressure changes, and switching
An air conditioner that allows simultaneous cooling and heating operation that can be changed quickly
There is an effect that the resulting Ru.

[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 explaining an operation state of only cooling or heating of the air-conditioning apparatus according to Embodiment 1 of the present invention.

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

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

FIG. 5 shows the configuration of a valve control means system of first and third opening / closing valves, a flow control means system of a first flow control apparatus, and an indoor blower control means system of the air conditioner according to Embodiment 1 of the present invention. FIG.

FIG. 6 is a flowchart of a valve control means system, a flow rate control means system, and an indoor blower control means system of the air conditioner according to the embodiment of the present invention.

FIG. 7 is a graph showing a pressure change in a connection portion between the first branch portion of the repeater and the first connection pipe on the indoor side in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 8 is an overall configuration diagram mainly showing a refrigerant system of a conventional air conditioner.

9 is an operation state diagram of only cooling or heating of the air-conditioning apparatus shown in FIG.

FIG. 10 is a diagram showing an operation state of the air conditioning apparatus shown in FIG. 8 mainly for heating.

11 is an operation state diagram of the air conditioning apparatus shown in FIG. 8 mainly for cooling.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way switching valve 3 Heat exchanger side heat exchanger 4 Accumulator 5 Indoor heat exchanger 6, 6b, 6c, 6d First connection pipe and indoor first connection pipe 7, 7b, 7c, 7d First 2 connection pipe and indoor side second connection pipe 9 first flow control device 10 first branch portion 11 second branch portion 13 second flow control device 14 bypass pipe 15 third flow control device 19, 16a, 16b, 16c, 16d First, second, and third heat exchange units 17 Fourth flow control device 21 First on-off valve 22 Second on-off valve 23 Third on-off valve 40 Flow switching valve Device 80 Indoor blower A Heat source unit B, C, D Indoor unit E Repeater 60 Valve control means 61 First timekeeping means 62 Flow control device 63 Indoor blower control means 64 Second timekeeping means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomohiko Kasai 6-5-666 Tehira, Wakayama City Mitsubishi Electric Corporation Wakayama Works (72) Inventor Shigeo Takada 6-5-666 Teira Wakayama City Mitsubishi Electric Inside Wakayama Works, Ltd. (72) Inventor Junichi Kameyama 6-66, Tehira, Wakayama City Mitsubishi Electric Wakayama Works, Ltd. (56) References JP-A-3-260561 (JP, A)

Claims (1)

(57) [Claims] 1. A compressor, a switching valve, a heat exchanger on a heat source unit side, etc.
And one indoor heat exchanger.
To a plurality of indoor units through the first and second connection pipes
Connect one of the indoor heat exchangers of the plurality of indoor units
A first switching valve, which is a cooling switching valve, and a heating switching
The first connection through a second on-off valve,
Switchable connection to pipe or second connection pipe
A first branch portion and the other of the plurality of indoor heat exchangers
Each connected via a first flow control device, and
A second branch portion connected to the second connection pipe;
A pipe that branches from the connection pipe 2 and reaches the first branch section
Pipe branching section, and the pipe branching section and the second
It is provided in the middle of the pipeline connecting the branch and controls the refrigerant flow rate.
A second flow control device, the second branch, and the
A fourth flow control device that communicates with the first connection pipe;
The heat source unit is provided between the first and second connection pipes,
By always changing the direction of the refrigerant
The first connection pipe interposed between the heat source unit and the indoor unit
To reduce the pressure of the second connection pipe to high pressure
In simultaneous heating and cooling operation an air conditioner capable of having a conversion device, the third on-off valve of a small capacity than the flow rate capacity of the first on-off valve for bypass on the Symbol first on-off valve is provided, the indoor unit When the cooling operation is started, the third opening / closing valve is opened, the indoor blower is started, and after the opening time of the third opening / closing valve has elapsed for a predetermined time, the first opening / closing valve is opened. An air conditioner wherein the first flow control device starts flow control according to a cooling load.